Group – HVAC Templates[LINK]
This group of objects allows for the specification of
simple zone thermostats and HVAC systems with automatically
generated node names. The combinations of HVACTemplate objects
are shown below.
The only other HVAC related objects besides the
HVACTemplate objects that need to be specified related to HVAC
systems are:
- Schedule:Year or
Schedule:Compact
- SizingPeriod objects (one for heating and one for cooling)
Note: all SizingPeriod objects can be used but for simplicity
in the following descriptions, we will only reference
SizingPeriod:DesignDay
- SimulationControl
- Sizing:Parameters
This makes the input requirements much smaller but
sacrifices some of the flexibility normally found in
EnergyPlus.
HVACTemplate:Thermostat[LINK]
Each type of HVAC template zone object may reference one of
these HVAC template thermostat objects. Multiple HVAC template
zones can reference the same HVAC template thermostat object.
The object allows the setpoints to be specified either as a
constant for the entire simulation or as schedules. Referenced
schedules must be defined elsewhere in the idf. Thermostat
control type is dual setpoint with deadband. This object may
be omitted and the user may define zone thermostat controls
directly using standard EnergyPlus objects ([ZoneControl:Thermostat](../input-output-reference/page-037.html#zonecontrolthermostat)
and related objects).
A name used to reference this object. This name is
referenced by HVACTemplate:Zone objects: i.e., HVACTemplate:Zone:IdealLoadsAirSystem,
HVACTemplate:Zone:FanCoil,
HVACTemplate:Zone:Unitary,
HVACTemplate:Zone:VAV
or HVACTemplate:Zone:VAV:FanPowered
objects.
Field: Heating
Setpoint Schedule Name[LINK]
Enter the name of a heating setpoint schedule that has
values that change at different times of the day or year. If a
constant set point is needed simply leave this field blank and
use the next field. The values in the schedule are in degrees
C.
Field: Constant
Heating Setpoint[LINK]
Enter the heating setpoint temperature in degrees C if
constant throughout the year. If the previous field is used
this field should be left blank and will be ignored.
Field: Cooling
Setpoint Schedule Name[LINK]
Enter the name of a cooling setpoint schedule that has
values that change at different times of the day or year. If a
constant set point is needed simply leave this field blank and
use the next field. The values in the schedule are in degrees
C.
Field: Constant
Cooling Setpoint[LINK]
Enter the cooling setpoint temperature in degrees C if
constant throughout the year. If the previous field is used
this field should be left blank and will be ignored.
As shown in an IDF:
HVACTemplate:Thermostat,
Office Thermostat, !- Thermostat Name
Htg-SetP-Sch, !- Heating Setpoint Schedule
, !- Constant Heating Setpoint {C}
Clg-SetP-Sch, !- Cooling Setpoint Schedule
; !- Constant Cooling Setpoint {C}
HVACTemplate:Zone:IdealLoadsAirSystem[LINK]
This object provides an ideal system to supply conditioned
air to the zone that meets all the load requirements and
consumes no energy. It is often used for load calculations, an
evaluation where the load components of the building are all
that is being investigated, or as the first step to a more
realistic model of a building.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:IdealLoadsAirSystem
objects can reference the same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
As shown in an IDF:
HVACTemplate:Zone:IdealLoadsAirSystem,
RESISTIVE ZONE, !- Zone Name
All Zones; !- Thermostat Name
HVACTemplate:Zone:FanCoil[LINK]
This object simulates a 4 pipe fan coil unit with hot water
heating coil, chilled water cooling coil, and an outdoor air
mixer. The coils are served directly by HVACTemplate:Plant:ChilledWaterLoop
and HVACTemplate:Plant:HotWaterLoop
objects. No HVACTemplate:System object is required. Reference
[ZoneHVAC:FourPipeFanCoil](../input-output-reference/page-032.html#zonehvacfourpipefancoil)
for more details about the fan coil model.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:* objects can reference the
same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
Field: Supply Air
Maximum Flow Rate[LINK]
By entering Autosize, the maximum supply air flow rate is
automatically determined for the zone based on the loads
experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday)
and cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
Note that the zone must have a thermostat specified in order
to autosize the flow rate. If a value is entered it is used as
the maximum supply air flow rate into the zone. It will be
multiplied by the Supply Air Sizing Factor and by zone
multipliers. The units are in m3/s.
Field: Zone Heating
Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone
design heating air flow rate and load will be multiplied by
the number input in this field when Supply Air Maximum Flow
Rate is autosized. If this field is left blank, the Heating
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone Cooling
Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone
design cooling air flow rate and load will be multiplied by
the number input in this field when Supply Air Maximum Flow
Rate is autosized. If this field is left blank, the Cooling
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Outdoor Air
Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone),
**or Flow/Person, Flow/Area, Sum,
Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow as the zone design outdoor air flow
rate. Flow/Person means the program will use the
input from the field Outdoor Air Flow per Person and
the maximum occupancy to calculate a zone design outdoor air
flow rate. Flow/Area means the program will use the
input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area to calculated a zone design outdoor air flow
rate. Sum means that the flows calculated from the
fields Outdoor Air Flow per Person, Outdoor Air
Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be added to obtain the zone design outdoor air flow rate.
Maximum means that the maximum flow derived from
Outdoor Air Flow per Person, Outdoor Air Flow per
Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be used for the zone design outdoor air flow rate. The
default is Flow/Person.
DetailedSpecification means that the outdoor air
specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object. These objects are referenced in the Design
Specification Outdoor Air Object Name and Design Specification
[Zone](../input-output-reference/page-011.html#zone)
Air Distribution Object Name fields below.
Field: Outdoor
Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone
in cubic meters per second. The default is 0.00944 (20 cfm per
person). An outdoor air flow rate is calculated based on the
total number of people for all [People](../input-output-reference/page-015.html#people)
statements assigned to the zone. Occupancy schedule values are
not applied. This input is used if Outdoor Air Method
is one of Outdoor Air Flow per Person, Sum,
or Maximum.
Field:
Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square
meter of floor area (units are m3/s-m2).
This input is multiplied by the zone area to obtain a flow
rate. This input is used if Outdoor Air Method is
Flow/Area, Sum or Maximum.
Field: Outdoor
Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic
meters per second. This input field is used if Outdoor Air
Method is Flow/Zone, Sum or
Maximum.
Field: System
Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. Fan coil systems
are modeled with continuous fan operation, so this is also the
supply fan operating schedule. If this field is blank, the
schedule has values of 1 for all time periods.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20oC
at sea level, 101325 Pa.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater than 0 and less
than or equal to 1.
Field:
Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the
air stream. A value of 0 means that the motor is completely
outside the air stream. A value of 1 means that all of the
motor heat will go into the air stream and act to cause a
temperature rise. Must be between 0 and 1.
Field: Cooling Coil Type[LINK]
There are two coil types available:
- ChilledWater
- ChilledWaterDetailedFlatModel
Chilled Water uses theCoil:Cooling:Water object
with the DetailedAnalysis option. This is the preferred coil
model for most applications.
ChilledWaterDetailedFlatModel uses the [Coil:Cooling:Water:DetailedGeometry](../input-output-reference/page-042.html#coilcoolingwaterdetailedgeometry)
object. This option is available for special applications. The
default is ChilledWater.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when cooling is only available seasonally. A
schedule value of one indicates that the cooling coil can be
on during a given time period. A value of zero denotes that
the cooling coil cannot be used during that time period.
Field: Cooling
Coil Design Setpoint[LINK]
This is the design supply air temperature in C used to size
the cooling supply air flow and the cooling coil. This field
is used only when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
14oC.
Field: Heating Coil Type[LINK]
Only one possible value may be entered here:
Future versions may have additional heating coil types.
Field:
Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when heating is only available seasonally. The
schedule values denote whether the heating coil can run during
a given time period. A schedule value of one indicates that
the heating coil can be on during a given time period. A value
of zero denotes that the heating coil cannot be used during
that time period
Field: Heating
Coil Design Setpoint[LINK]
This is the design supply air temperature in C used to size
the heating supply air flow and the heating coil. This field
is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
50oC.
Field:
Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir
object if this zone is served by a dedicated outdoor air
system (DOAS). When a Dedicated Outdoor Air System Name is
entered, the outdoor air flow rate for this zone equipment
object will be set to zero and the DOAS will provide the
ventilation air to the zone based on the outdoor air
specifications in this object. For this fancoil system (ref.
ZoneHVAC:FourPipeFanCoil):, the “Capacity Control Method” will
be set to CyclingFan if a DOAS system is specified. If this
field is blank, then the zone served by this fancoil system
will not be served by a DOAS, and the fancoil Capacity Control
Method will be ConstantFanVariableFlow.
This field selects the method for specifying the
cooling design supply air temperature.
SupplyAirTemperature means that the field Cooling
Coil Design Setpoint will be used for sizing the zone cooling
design air flow rate and the cooling coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design
supply air temperature and the zone air temperature in degrees
Celsius for the zone cooling design air flow rate calculation
and cooling coil sizing. The absolute value is used, so the
sign may be positive or negative. This field is used only when
[Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 11.11
deltaC.
This field selects the method for specifying the
heating design supply air temperature.
SupplyAirTemperature means that the field Heating
Coil Design Setpoint will be used for sizing the zone heating
design air flow rate and the heating coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and zone air temperature in degrees Celsius
for the zone heating design air flow rate calculation and
heating coil sizing. The absolute value is used, so the sign
may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 30 deltaC.
Field:
Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object which specifies the design outdoor air flow rate for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
Field:
Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object which specifies the air distribution effectiveness for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:FanCoil,
SPACE1-1, !- Zone Name
All Zones, !- Template Thermostat Name
autosize, !- Supply Air Maximum Flow Rate {m3/s}
, !- Zone Heating Sizing Factor
, !- Zone Cooling Sizing Factor
flow/person, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow Rate per Person {m3/s}
0.0, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
0.0, !- Outdoor Air Flow Rate per Zone {m3/s}
FanAvailSched, !- System Availability Schedule Name
0.7, !- Supply Fan Total Efficiency
75, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
ChilledWater, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule Name
12.5, !- Cooling Coil Design Setpoint {C}
HotWater, !- Heating Coil Type
, !- Heating Coil Availability Schedule Name
50, !- Heating Coil Design Setpoint {C}
, !- Dedicated Outdoor Air System Name
SupplyAirTemperature, !- Zone Cooling Design Supply Air Temperature Input Method
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC]
SupplyAirTemperature, !- Zone Heating Design Supply Air Temperature Input Method
, !- Zone Heating Design Supply Air Temperature Difference {deltaC]
, !- Design Specification Outdoor Air Object Name
; !- Design Specification Zone Air Distribution Object Name
HVACTemplate:Zone:PTAC[LINK]
This object simulates a packaged terminal air conditioner
(PTAC) with a DX cooling coil, a heating coil (electric, gas,
or hot water), and an outdoor air mixer. The optional hot
water heating coil is served directly by HVACTemplate:Plant:HotWaterLoop
and HVACTemplate:Plant:Boiler
objects. No HVACTemplate:System object is required. Reference
[ZoneHVAC:PackagedTerminalAirConditioner](../input-output-reference/page-032.html#zonehvacpackagedterminalairconditioner)
for more details about the PTAC model.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:* objects can reference the
same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
Field: Cooling
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the DX
cooling coil is operating. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered, it will be multiplied by the Supply Air
Sizing Factor and by zone multipliers. The units are in m3/s.
The default is autosize.
Field: Heating
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the
heating coil is operating. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered, it will be multiplied by the Supply Air
Sizing Factor and by zone multipliers. The units are in m3/s.
The default is autosize.
Field: No Load
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither
cooling nor heating is required (i.e., DX coil and heater are
off but the supply air fan operates). This field is only used
when the supply air fan operating mode schedule specifies
continuous fan operation. Values must be greater than or equal
to zero, or this field is autosizable. If the air
conditioner’s supply air fan operating mode schedule specifies
continuous fan operation and this value is set to zero or this
field is left blank, then the model assumes that the supply
air flow rate when no cooling/heating is needed is equal to
the supply air flow rate when the cooling or heating coil was
last operating (for cooling operation or heating operation).
By entering Autosize, the supply air flow rate will be sized
to match the smaller of the Cooling and Heating flow rates. A
value entered in this field will not be multiplied by
the sizing factor or by zone multipliers. It is best to
autosize or leave blank when using zone multipliers.The units
are in m3/s. The default is autosize.
Field: Zone
Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone
design heating air flow rate and load will be multiplied by
the number input in this field when Heating Supply Air Flow
Rate is autosized. If this field is left blank, the Heating
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone
Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone
design cooling air flow rate and load will be multiplied by
the number input in this field when Cooling Supply Air Flow
Rate is autosized. If this field is left blank, the Cooling
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Outdoor Air
Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone),
**or Flow/Person, Flow/Area, Sum,
Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow as the zone design outdoor air flow
rate. Flow/Person means the program will use the
input from the field Outdoor Air Flow per Person and
the maximum occupancy to calculate a zone design outdoor air
flow rate. Flow/Area means the program will use the
input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area to calculated a zone design outdoor air flow
rate. Sum means that the flows calculated from the
fields Outdoor Air Flow per Person, Outdoor Air
Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be added to obtain the zone design outdoor air flow rate.
Maximum means that the maximum flow derived from
Outdoor Air Flow per Person, Outdoor Air Flow per
Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be used for the zone design outdoor air flow rate. The
default is Flow/Person.
DetailedSpecification means that the outdoor air
specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object. These objects are referenced in the Design
Specification Outdoor Air Object Name and Design Specification
[Zone](../input-output-reference/page-011.html#zone)
Air Distribution Object Name fields below.
Field:
Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone
in cubic meters per second. The default is 0.00944 (20 cfm per
person). An outdoor air flow rate is calculated based on the
total number of people for all [People](../input-output-reference/page-015.html#people)
statements assigned to the zone. Occupancy schedule values are
not applied. This input is used if Outdoor Air Method
is one of Outdoor Air Flow per Person, Sum,
or Maximum.
Field:
Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square
meter of floor area (units are m3/s-m2).
This input is multiplied by the zone area to obtain a flow
rate. This input is used if Outdoor Air Method is
Flow/Area, Sum or Maximum.
Field: Outdoor
Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic
meters per second. This input field is used if Outdoor Air
Method is Flow/Zone, Sum or
Maximum.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. When the fan
operating mode schedule indicates continuous fan operation,
the fan will operate whenever this schedule is 1.0. If the fan
operating schedule indicates cycling fan operation, then fan
will only cycle on as needed to meet a load.
Field:
Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan
operating mode schedule. The supply air fan operating mode may
vary during the simulation based on time-of-day or with a
change of season. Schedule values of 0 denote that the supply
air fan and the heating or cooling coil cycle on and off
together to meet the heating or cooling load (a.k.a. AUTO
fan). Schedule values other than 0 denote that the supply fan
runs continuously while the heating or cooling coil cycles to
meet the load. The keywords Cycling or
Continuous may also be used to specify a single mode
of operation for the entire simulation. The default is
Cycling.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the cooling and heating coils. BlowThrough
models a system where the supply air fan is before the cooling
and heating coils. The default is DrawThrough.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1. The
default is 0.7.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20oC
at sea level, 101325 Pa. The default is 75.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater than 0 and less
than or equal to 1. The default is 0.9.
Field: Cooling Coil
Type[LINK]
Enter the type of cooling coil. There is currently only one
choices for this field, SingleSpeedDX.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when cooling is only available seasonally. A
schedule value of 1.0 indicates that the cooling coil can be
on during a given time period. A value of zero denotes that
the cooling coil cannot be used during that time period.
Field: Cooling Coil
Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm
determine the cooling coil capacity based on the maximum
cooling loads during the cooling design day. If a value is
entered, it represents the full load cooling capacity,
including both sensible and latent capacity, in watts of the
DX coil unit at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Capacity should be the “gross”
capacity where the impact of supply air fan heat is NOT
included. The units are in W. The default is autosize.
Field:
Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine
the sensible heat ratio based on the rated capacity and air
flow rate. Otherwise, enter the value of the ratio of the
sensible capacity divided by total cooling capacity of the DX
cooling coil at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Both the sensible and total
cooling capacities used to define the Rated Sensible Heat
Ratio (SHR) should be “gross” capacity where the impact of
supply air fan heat is NOT included. The default is
autosize.
Field: Cooling Coil
Rated COP[LINK]
Enter the coefficient of performance defined as the gross
cooling coil capacity in watts divided by electrical power
input in watts of the DX cooling coil unit at rated
conditions. Rated conditions are air entering the cooling coil
at the maximum supply air flow rate at 26.7°C drybulb/19.4°C
wetbulb with air entering the outdoor condenser coil at 35°C
drybulb. The input power includes electric power for the
compressor and condenser fan but does not include the power
consumption of the supply air fan. The default is 3.0.
Field: Heating Coil
Type[LINK]
Enter the type of heating coil. The choices for this field
are
If HotWater is specified, then a HVACTemplate:Plant:HotWaterLoop
and a HVACTemplate:Plant:Boiler
must be included in the input file to serve this hot water
coil. The default is Electric.
Field:
Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when heating is only available seasonally. The
schedule values denote whether the heating coil can run during
a given time period. A schedule value of 1.0 indicates that
the heating coil can be on during a given time period. A value
of zero denotes that the heating coil cannot be used during
that time period
Field: Heating Coil
Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the coil can deliver in Watts.
The default is autosize.
Field: Gas Heating
Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent.
A burner that is 80% efficient would have an entry of 0.8
here, which is the default. This field applies only if the
heating coil type is gas.
Field:
Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
heating coil operation, such as a combustion fan. The units
are in W. This field applies only if the heating coil type is
gas.
Field:
Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir
object if this zone is served by a dedicated outdoor air
system (DOAS). When a Dedicated Outdoor Air System Name is
entered, the outdoor air flow rate for this zone equipment
object (ref. ZoneHVAC: PackagedTerminalAirConditioner) will be
set to zero and the DOAS will provide the ventilation air to
the zone based on the outdoor air specifications in this
object. If this field is blank, then the zone served by this
PTAC system will not be served by a DOAS.
This field selects the method for specifying the
cooling design supply air temperature.
SupplyAirTemperature means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature will be used for sizing
the zone cooling design air flow rate and the cooling coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
cooling design air flow rate calculation and cooling coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
14oC.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design
supply air temperature and the zone air temperature in degrees
Celsius for the zone cooling design air flow rate calculation
and cooling coil sizing. The absolute value is used, so the
sign may be positive or negative. This field is used only when
[Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 11.11
deltaC.
This field selects the method for specifying the
heating design supply air temperature.
SupplyAirTemperature means that the field Heating
Coil Design Setpoint will be used for sizing the zone heating
design air flow rate and the heating coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
heating design air flow rate calculation and heating coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
50oC.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and zone air temperature in degrees Celsius
for the zone heating design air flow rate calculation and
heating coil sizing. The absolute value is used, so the sign
may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 30 deltaC.
Field:
Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object which specifies the design outdoor air flow rate for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
Field:
Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object which specifies the air distribution effectiveness for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:PTAC,
SPACE1-1, !- Zone Name
All Zones, !- Template Thermostat Name
autosize, !- Cooling Supply Air Flow Rate {m3/s}
autosize, !- Heating Supply Air Flow Rate {m3/s}
, !- No Load Supply Air Flow Rate {m3/s}
, !- Zone Heating Sizing Factor
, !- Zone Cooling Sizing Factor
flow/person, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow Rate per Person {m3/s}
, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
, !- Outdoor Air Flow Rate per Zone {m3/s}
, !- System Availability Schedule Name
Cycling, !- Supply Fan Operating Mode Schedule Name
DrawThrough, !- Supply Fan Placement
0.7, !- Supply Fan Total Efficiency
75, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
SingleSpeedDX, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule Name
autosize, !- Cooling Coil Rated Capacity {W}
autosize, !- Cooling Coil Rated Sensible Heat Ratio
3, !- Cooling Coil Rated COP
Electric, !- Heating Coil Type
, !- Heating Coil Availability Schedule Name
autosize, !- Heating Coil Capacity {W}
0.8, !- Gas Heating Coil Efficiency
, !- Gas Heating Coil Parasitic Electric Load {W}
, !- Dedicated Outdoor Air System Name
SupplyAirTemperature, !- Zone Cooling Design Supply Air Temperature Input Method
14.0, !- Zone Cooling Design Supply Air Temperature {C]
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC]
SupplyAirTemperature, !- Zone Heating Design Supply Air Temperature Input Method
50.0, !- Zone Heating Design Supply Air Temperature {C]
, !- Zone Heating Design Supply Air Temperature Difference {deltaC]
, !- Design Specification Outdoor Air Object Name
; !- Design Specification Zone Air Distribution Object Name
HVACTemplate:Zone:PTHP[LINK]
This object simulates a packaged terminal air-to-air heat
pump (PTHP) with a DX cooling coil, a DX air-to-air heat pump
heating coil, a supplemental heating coil (electric or gas),
and an outdoor air mixer. No HVACTemplate:System object is
required. Reference [ZoneHVAC:PackagedTerminalHeatPump](../input-output-reference/page-032.html#zonehvacpackagedterminalheatpump)
for more details about the PTHP model.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:* objects can reference the
same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
Field: Cooling
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the DX
cooling coil is operating. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered, it will be multiplied by the Supply Air
Sizing Factor and by zone multipliers. The units are in m3/s.
The default is autosize.
Field: Heating
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the
heating coil is operating. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered, it will be multiplied by the Supply Air
Sizing Factor and by zone multipliers. The units are in m3/s.
The default is autosize.
Field: No Load
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither
cooling nor heating is required (i.e., DX coil and heater are
off but the supply air fan operates). This field is only used
when the supply air fan operating mode schedule specifies
continuous fan operation. Values must be greater than or equal
to zero, or this field is autosizable. If the air
conditioner’s supply air fan operating mode schedule specifies
continuous fan operation and this value is set to zero or this
field is left blank, then the model assumes that the supply
air flow rate when no cooling/heating is needed is equal to
the supply air flow rate when the cooling or heating coil was
last operating (for cooling operation or heating operation).
By entering Autosize, the supply air flow rate will be sized
to match the smaller of the Cooling and Heating flow rates. A
value entered in this field will not be multiplied by
the sizing factor or by zone multipliers. It is best to
autosize or leave blank when using zone multipliers. The units
are in m3/s. The default is autosize.
Field: Zone
Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone
design heating air flow rate and load will be multiplied by
the number input in this field when Heating Supply Air Flow
Rate is autosized. If this field is left blank, the Heating
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone
Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone
design cooling air flow rate and load will be multiplied by
the number input in this field when Cooling Supply Air Flow
Rate is autosized. If this field is left blank, the Cooling
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Outdoor Air
Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone),
**or Flow/Person, Flow/Area, Sum,
Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow as the zone design outdoor air flow
rate. Flow/Person means the program will use the
input from the field Outdoor Air Flow per Person and
the maximum occupancy to calculate a zone design outdoor air
flow rate. Flow/Area means the program will use the
input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area to calculated a zone design outdoor air flow
rate. Sum means that the flows calculated from the
fields Outdoor Air Flow per Person, Outdoor Air
Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be added to obtain the zone design outdoor air flow rate.
Maximum means that the maximum flow derived from
Outdoor Air Flow per Person, Outdoor Air Flow per
Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be used for the zone design outdoor air flow rate. The
default is Flow/Person.
DetailedSpecification means that the outdoor air
specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object. These objects are referenced in the Design
Specification Outdoor Air Object Name and Design Specification
[Zone](../input-output-reference/page-011.html#zone)
Air Distribution Object Name fields below.
Field:
Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone
in cubic meters per second. The default is 0.00944 (20 cfm per
person). An outdoor air flow rate is calculated based on the
total number of people for all [People](../input-output-reference/page-015.html#people)
statements assigned to the zone. Occupancy schedule values are
not applied. This input is used if Outdoor Air Method
is one of Outdoor Air Flow per Person, Sum,
or Maximum.
Field:
Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square
meter of floor area (units are m3/s-m2).
This input is multiplied by the zone area to obtain a flow
rate. This input is used if Outdoor Air Method is
Flow/Area, Sum or Maximum.
Field: Outdoor
Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic
meters per second. This input field is used if Outdoor Air
Method is Flow/Zone, Sum or
Maximum.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. When the fan
operating mode schedule indicates continuous fan operation,
the fan will operate whenever this schedule is 1.0. If the fan
operating schedule indicates cycling fan operation, then fan
will only cycle on as needed to meet a load.
Field:
Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan
operating mode schedule. The supply air fan operating mode may
vary during the simulation based on time-of-day or with a
change of season. Schedule values of 0 denote that the supply
air fan and the heating or cooling coil cycle on and off
together to meet the heating or cooling load (a.k.a. AUTO
fan). Schedule values other than 0 denote that the supply fan
runs continuously while the heating or cooling coil cycles to
meet the load. The keywords Cycling or
Continuous may also be used to specify a single mode
of operation for the entire simulation. The default is
Cycling.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the cooling and heating coils. BlowThrough
models a system where the supply air fan is before the cooling
and heating coils. The default is DrawThrough.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1. The
default is 0.7.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20oC
at sea level, 101325 Pa. The default is 75.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater than 0 and less
than or equal to 1. The default is 0.9.
Field: Cooling Coil
Type[LINK]
Enter the type of cooling coil. There is currently only one
choices for this field, SingleSspeedDX.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when cooling is only available seasonally. A
schedule value of 1.0 indicates that the cooling coil can be
on during a given time period. A value of zero denotes that
the cooling coil cannot be used during that time period.
Field: Cooling
Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm
determine the cooling coil capacity based on the maximum
cooling loads during the cooling design day. If a value is
entered, it represents the full load cooling capacity,
including both sensible and latent capacity, in watts of the
DX coil unit at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Capacity should be the “gross”
capacity where the impact of supply air fan heat is NOT
included. The units are in W. The default is autosize.
Field:
Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine
the sensible heat ratio based on the rated capacity and air
flow rate. Otherwise, enter the value of the ratio of the
sensible capacity divided by total cooling capacity of the DX
cooling coil at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Both the sensible and total
cooling capacities used to define the Rated Sensible Heat
Ratio (SHR) should be “gross” capacity where the impact of
supply air fan heat is NOT included. The default is
autosize.
Field: Cooling Coil
Rated COP[LINK]
Enter the coefficient of performance defined as the gross
cooling coil capacity in watts divided by electrical power
input in watts of the DX cooling coil unit at rated
conditions. Rated conditions are air entering the cooling coil
at the maximum supply air flow rate at 26.7°C drybulb/19.4°C
wetbulb with air entering the outdoor condenser coil at 35°C
drybulb. The input power includes electric power for the
compressor and condenser fan but does not include the power
consumption of the supply air fan. The default is 3.0.
Field: Heat Pump
Heating Coil Type[LINK]
Enter the type of heat pump heating coil. There is
currently only one choices for this field,
SingleSpeedDXHeatPump.
Field:
Heat Pump Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heat pump heating
coil to be available anytime the system is operating. If a
schedule name is specified, it defines when the coil is
available. This is most often used when heating is only
available seasonally. A schedule value of 1.0 indicates that
the heat pump heating coil can be on during a given time
period. A value of zero denotes that the heat pump heating
coil cannot be used during that time period.
Field:
Heat Pump Heating Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm
determine the heat pump heating coil capacity based on the
maximum heating loads during the heating design day. If a
value is entered, it represents the full load heating
capacity, in watts of the DX heat pump unit at rated
conditions. Rated conditions are air entering the heat pump
heating coil at the heating supply air flow rate at 21.11°C
drybulb/15.55°C wetbulb with air entering the outdoor coil at
8.33°C drybulb/6.11C wetbulb. Capacity should be the “gross”
capacity where the impact of supply air fan heat is NOT
included. The units are in W. The default is autosize.
Field: Heat
Pump Heating Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross
heating coil capacity in watts divided by electrical power
input in watts of the DX heating coil unit at rated
conditions. Rated conditions are air entering the heat pump
heating coil at the heating supply air flow rate at 21.11°C
drybulb/15.55°C wetbulb with air entering the outdoor coil at
8.33°C drybulb/6.11C wetbulb. The input power includes
electric power for the compressor and condenser fan but does
not include the power consumption of the supply air fan. The
default is 2.75.
Field:
Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the minimum outdoor dry-bulb
temperature in degrees Celsius for PTHP compressor operation.
The compressor will not operate (for DX heating or DX cooling)
when outdoor dry-bulb temperatures fall below this value. The
minimum value must be greater than or equal to -20 °C. The
default value is -8°C.
Field:
Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the outdoor air dry-bulb
temperature above which outdoor coil defrosting is disabled.
The temperature for this input field must be greater than or
equal to 0 C and less than or equal to 7.22 C. If this input
field is left blank, the default value is 5 C.
Field: Heat Pump
Defrost Strategy[LINK]
This alpha field has two choices: ReverseCycle or
Resistive. If the ReverseCycle strategy is
selected, the heating cycle is reversed periodically to
provide heat to melt frost accumulated on the outdoor coil. If
a Resistive defrost strategy is selected, the frost
is melted using an electric resistance heater. If this input
field is left blank, the default defrost strategy is
ReverseCycle.
Field: Heat Pump
Defrost Control[LINK]
This alpha field has two choices: Timed or
OnDemand. If Timed control is selected, the
defrost time period is calculated based on a fixed value or
compressor runtime whether or not frost has actually
accumulated. For Timed defrost control, the
fractional amount of time the unit is in defrost is entered in
the input field “Defrost Time Period Fraction” described
below. If OnDemand defrost control is selected, the
defrost time period is calculated based on outdoor weather
(humidity ratio) conditions. Regardless of which defrost
control is selected, defrost does not occur above the user
specified outdoor temperature entered in the input field “Heat
Pump Defrost Maximum Outdoor Dry-Bulb Temperature” described
above. If this input field is left blank, the default defrost
control is Timed.
Field:
Heat Pump Defrost Time Period Fraction[LINK]
This numeric field defines the fraction of compressor
runtime when the defrost cycle is active, and only applies to
“timed” defrost (see Heat Pump Defrost Control input field
above). For example, if the defrost cycle is active for 3.5
minutes for every 60 minutes of compressor runtime, then the
user should enter 3.5/60 = 0.058333. The value for this input
field must be greater than or equal to 0. If this input field
is left blank, the default value is 0.058333.
Field:
Supplemental Heating Coil Type[LINK]
Enter the type of supplemental heating coil. The choices
for this field are
The default is Electric.
Field:
Supplemental Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the supplemental heating
coil to be available anytime the system is operating. If a
schedule name is specified, it defines when the coil is
available. This is most often used when supplemental heating
is only available seasonally. The schedule values denote
whether the supplemental heating coil can run during a given
time period. A schedule value of 1.0 indicates that the
supplemental heating coil can be on during a given time
period. A value of zero denotes that the supplemental heating
coil cannot be used during that time period
Field:
Supplemental Heating Coil Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the supplemental heating coil
can deliver in Watts. The default is autosize.
Field:
Supplemental Heating Coil Maximum Outdoor Dry-Bulb
Temperature[LINK]
This numeric field defines the outdoor air dry-bulb
temperature above which the supplemental heating coil is
disabled. The temperature for this input field must be less
than or equal to 21 C. If this input field is left blank, the
default value is 21 C.
Field:
Supplemental Gas Heating Coil Efficiency[LINK]
Enter supplemental heating coil gas burner efficiency as a
decimal, not as a percent. A burner that is 80% efficient
would have an entry of 0.8 here, which is the default. This
field applies only if the supplemental heating coil type is
gas.
Field:
Supplemental Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
supplemental heating coil operation, such as a combustion fan.
The units are in W. The default is 0.0. This field applies
only if the supplemental heating coil type is gas.
Field:
Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir
object if this zone is served by a dedicated outdoor air
system (DOAS). When a Dedicated Outdoor Air System Name is
entered, the outdoor air flow rate for this zone equipment
object (ref. [ZoneHVAC:PackagedTerminalHeatPump](../input-output-reference/page-032.html#zonehvacpackagedterminalheatpump))
will be set to zero and the DOAS will provide the ventilation
air to the zone based on the outdoor air specifications in
this object. If this field is blank, then the zone served by
this PTHP system will not be served by a DOAS.
This field selects the method for specifying the
cooling design supply air temperature.
SupplyAirTemperature means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature will be used for sizing
the zone cooling design air flow rate and the cooling coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
cooling design air flow rate calculation and cooling coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
14oC.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design
supply air temperature and the zone air temperature in degrees
Celsius for the zone cooling design air flow rate calculation
and cooling coil sizing. The absolute value is used, so the
sign may be positive or negative. This field is used only when
[Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 11.11
deltaC.
This field selects the method for specifying the
heating design supply air temperature.
SupplyAirTemperature means that the field Heating
Coil Design Setpoint will be used for sizing the zone heating
design air flow rate and the heating coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
heating design air flow rate calculation and heating coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
50oC.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and zone air temperature in degrees Celsius
for the zone heating design air flow rate calculation and
heating coil sizing. The absolute value is used, so the sign
may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 30 deltaC.
Field:
Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object which specifies the design outdoor air flow rate for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
Field:
Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object which specifies the air distribution effectiveness for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:PTHP,
SPACE1-1, !- Zone Name
All Zones, !- Template Thermostat Name
autosize, !- Cooling Supply Air Flow Rate {m3/s}
autosize, !- Heating Supply Air Flow Rate {m3/s}
, !- No Load Supply Air Flow Rate {m3/s}
, !- Zone Heating Sizing Factor
, !- Zone Cooling Sizing Factor
flow/person, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow Rate per Person {m3/s}
, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
, !- Outdoor Air Flow Rate per Zone {m3/s}
, !- System Availability Schedule Name
Cycling, !- Supply Fan Operating Mode Schedule Name
DrawThrough, !- Supply Fan Placement
0.7, !- Supply Fan Total Efficiency
75, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
SingleSpeedDX, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule Name
autosize, !- Cooling Coil Rated Capacity {W}
autosize, !- Cooling Coil Rated Sensible Heat Ratio
3, !- Cooling Coil Rated COP
SingleSpeedDXHeatPump, !- Heat Pump Heating Coil Type
, !- Heat Pump Heating Coil Availability Schedule Name
autosize, !- Heat Pump Heating Coil Rated Capacity {W}
2.75, !- Heat Pump Heating Coil Rated COP
-8, !- Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature {C}
5, !- Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature {C}
ReverseCycle, !- Heat Pump Defrost Strategy
Timed, !- Heat Pump Defrost Control
0.058333, !- Heat Pump Defrost Time Period Fraction
Electric, !- Supplemental Heating Coil Type
, !- Supplemental Heating Coil Availability Schedule Name
autosize, !- Supplemental Heating Coil Capacity {W}
21, !- Supplemental Heating Coil Max Outdoor Dry-Bulb Temperature {C}
0.8, !- Supplemental Gas Heating Coil Efficiency
, !- Supplemental Gas Heating Coil Parasitic Electric Load {W}
, !- Dedicated Outdoor Air System Name
SupplyAirTemperature, !- Zone Cooling Design Supply Air Temperature Input Method
14.0, !- Zone Cooling Design Supply Air Temperature {C]
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC]
SupplyAirTemperature, !- Zone Heating Design Supply Air Temperature Input Method
50.0, !- Zone Heating Design Supply Air Temperature {C]
, !- Zone Heating Design Supply Air Temperature Difference {deltaC]
, !- Design Specification Outdoor Air Object Name
; !- Design Specification Zone Air Distribution Object Name
HVACTemplate:Zone:Unitary[LINK]
This object simulates the zone portion of a constant volume
direct-expansion based HVAC configuration with several
different heating options. Often a single HVACTemplate:Zone:Unitary
object will be used with a single HVACTemplate:System:Unitary
object to simulate single zone direct-expansion based air
conditioning systems. In addition, multiple HVACTemplate:Zone:Unitary
objects may appear that all reference the same HVACTemplate:System:Unitary
object in a multiple zone version. For a multizone system,
only one zone is specified as the control zone (see HVACTemplate:System:Unitary
for more information). Direct expansion includes single
packaged rooftop systems commonly seen in commercial
applications and split systems commonly seen in residential
applications.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template
Unitary System Name[LINK]
Enter the name of the HVACTemplate:System:Unitary
object serving this zone.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:* objects can reference the
same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
Field: Supply
Air Maximum Flow Rate[LINK]
By entering Autosize, the maximum supply air flow rate is
automatically determined for the zone based on the loads
experienced by the zone during the specified heating
SizingPeriod:DesignDay](page-008.html#sizingperioddesignday)
and cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
Note that the zone must have a thermostat specified in order
to autosize the flow rate, even if it is not the control zone
in a multiple zone unitary system. If a value is entered it is
used as the maximum supply air flow rate into the zone. It
will be multiplied by the Supply Air Sizing Factor and by zone
multipliers. The [HVACTemplate:System:Unitary object that is
referenced also allows the specification of supply air flow.
If the value is specified at the system level it will scale
the zone values to match. The units are in m3/s.
Field: Zone
Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone
design heating air flow rate and load will be multiplied by
the number input in this field when Supply Air Maximum Flow
Rate is autosized. If this field is left blank, the Heating
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone
Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone
design cooling air flow rate and load will be multiplied by
the number input in this field when Supply Air Maximum Flow
Rate is autosized. If this field is left blank, the Cooling
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Outdoor Air
Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone),
**or Flow/Person, Flow/Area, Sum,
Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow as the zone design outdoor air flow
rate. Flow/Person means the program will use the
input from the field Outdoor Air Flow per Person and
the maximum occupancy to calculate a zone design outdoor air
flow rate. Flow/Area means the program will use the
input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area to calculated a zone design outdoor air flow
rate. Sum means that the flows calculated from the
fields Outdoor Air Flow per Person, Outdoor Air
Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be added to obtain the zone design outdoor air flow rate.
Maximum means that the maximum flow derived from
Outdoor Air Flow per Person, Outdoor Air Flow per
Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be used for the zone design outdoor air flow rate. The
default is Flow/Person.
DetailedSpecification means that the outdoor air
specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object. These objects are referenced in the Design
Specification Outdoor Air Object Name and Design Specification
[Zone](../input-output-reference/page-011.html#zone)
Air Distribution Object Name fields below.
If the air handler serving this zone serves more than one
zone, the total outdoor air flow for the system is the sum of
the zone outdoor air flows if the system outdoor air flow is
autosized. Since the zones share a single outdoor air source,
the amount of outdoor air actually delivered to the zone is
based on the fraction of supply air delivered to the zone to
the total supply air from the system.
Field:
Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone
in cubic meters per second. The default is 0.00944 (20 cfm per
person). An outdoor air flow rate is calculated based on the
total number of people for all [People](../input-output-reference/page-015.html#people)
statements assigned to the zone. Occupancy schedule values are
not applied. This input is used if Outdoor Air Method
is one of Outdoor Air Flow per Person, Sum,
or Maximum.
Field:
Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square
meter of floor area (units are m3/s-m2).
This input is multiplied by the zone area to obtain a flow
rate. This input is used if Outdoor Air Method is
Flow/Area, Sum or Maximum.
Field: Outdoor
Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic
meters per second. This input field is used if Outdoor Air
Method is Flow/Zone, Sum or
Maximum.
Field: Supply Plenum
Name[LINK]
This field allows the user to specify a supply plenum which
serves only this zone. The plenum zone is added to the supply
air path after the system splitter or system-level supply
plenum and before the zone terminal unit. Set to blank if no
[AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
is to be modeled. If a [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
is modeled, it must be modeled as a zone with surfaces, and
the name of the plenum zone should be entered here.
Field: Return Plenum
Name[LINK]
This field allows the user to specify a return plenum which
serves only this zone. The plenum zone is added to the return
air path immediately after the zone and before the system
mixer or system-level return plenum. Set to blank if no zone
return plenum is to be modeled. If a zone return plenum is
modeled, it must be modeled as a zone with surfaces, and the
name of the plenum zone should be entered here.
Field: Baseboard Heating
Type[LINK]
This field specifies the availability of thermostatically
controlled baseboard heat in this zone. The choices are:
The default choice is None.
Field:
Baseboard Heating Availability Schedule Name[LINK]
Leave this field blank if you want the baseboard heating to
be available for the entire year to perform heating if called
for by the thermostat. If a schedule name is specified, those
times that the baseboard heating is available should be
specified as 1.0. Those times that the basebaord heating is
not available should have a zero value in the schedule. Please
note that this is not a schedule of when the baseboard is
providing heat but a schedule of when it can provide heat.
Field: Baseboard
Heating Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the baseboard heating can
deliver in Watts. Note that EnergyPlus autosizing will
autosize the baseboard heating to meet the full heating load
of the zone, regardless of the heating capability of the
unitary air handling system. The baseboard heating will be set
to heating priority 2, which means it will meet any remaining
heating load not met by the unitary system. Prior to v7.1, the
capacity was only applied to electric baseboard. Starting with
v7.1, the capacity will be used for both hot water and
electric baseboard.
This field selects the method for specifying the
cooling design supply air temperature.
SupplyAirTemperature means that the field
Zone](page-011.html#zone) Cooling Design Supply Air
Temperature will be used for sizing the zone cooling design
air flow rate and the cooling coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used.
SystemSupplyAirTemperature means that the Cooling
Design Supply Air Temperature from the template unitary system
serving this zone will be used (Ref.
[HVACTemplate:System:Unitary or
HVACTemplate:System:UnitaryHeatPump:AirToAir). The default is
SystemSupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
cooling design air flow rate calculation and cooling coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is 12.8°C.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design
supply air temperature and the zone air temperature in degrees
Celsius for the zone cooling design air flow rate calculation
and cooling coil sizing. The absolute value is used, so the
sign may be positive or negative. This field is used only when
[Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 11.11
deltaC.
This field selects the method for specifying the
heating design supply air temperature.
SupplyAirTemperature means that the field Heating
Coil Design Setpoint will be used for sizing the zone heating
design air flow rate and the heating coil.
TemperatureDifference means that the field
Zone](page-011.html#zone) Heating Design Supply Air
Temperature Difference will be used.
SystemSupplyAirTemperature means that the Heating
Design Supply Air Temperature from the template unitary system
serving this zone will be used (Ref.
[HVACTemplate:System:Unitary or
HVACTemplate:System:UnitaryHeatPump:AirToAir). The default is
SystemSupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
heating design air flow rate calculation and heating coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is 50°C.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and zone air temperature in degrees Celsius
for the zone heating design air flow rate calculation and
heating coil sizing. The absolute value is used, so the sign
may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 30 deltaC.
Field:
Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object which specifies the design outdoor air flow rate for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
Field:
Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object which specifies the air distribution effectiveness for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:Unitary,
SPACE1-1, !- Zone Name
Furnace DX 1-1, !- Template Unitary System Name
All Zones, !- Template Thermostat Name
autosize, !- Supply Air Maximum Flow Rate {m3/s}
, !- Zone Heating Sizing Factor
, !- Zone Cooling Sizing Factor
flow/person, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow Rate per Person {m3/s}
0.0, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
0.0, !- Outdoor Air Flow Rate per Zone {m3/s}
, !- Supply Plenum Name
, !- Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule Name
Autosize, !- Baseboard Heating Capacity {W}
SystemSupplyAirTemperature, !- Zone Cooling Design Supply Air . . . Input Method
, !- Zone Cooling Design Supply Air Temperature {C]
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC]
SystemSupplyAirTemperature, !- Zone Heating Design Supply Air . . . Input Method
, !- Zone Heating Design Supply Air Temperature {C]
, !- Zone Heating Design Supply Air Temperature Difference {deltaC]
, !- Design Specification Outdoor Air Object Name
; !- Design Specification Zone Air Distribution Object Name
HVACTemplate:Zone:VAV[LINK]
This object simulates the zone portion of a variable air
volume HVAC configuration with several different heating
options. Multiple HVACTemplate:Zone:VAV
or HVACTemplate:Zone:VAV:FanPowered
objects are usually specified for each HVACTemplate:System:VAV
object. Reheat is specified at the zone level. Reference [AirTerminal:SingleDuct:VAV:Reheat](../input-output-reference/page-031.html#airterminalsingleductvavreheat)
and [AirTerminal:SingleDuct:VAV:NoReheat](../input-output-reference/page-031.html#airterminalsingleductvavnoreheat)
for more details about VAV terminal units.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template VAV
System Name[LINK]
Enter the name of the HVACTemplate:System:VAV
object serving this zone.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:* objects can reference the
same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
Field: Supply
Air Maximum Flow Rate[LINK]
By entering Autosize, the maximum supply air flow rate is
automatically determined for the zone based on the loads
experienced by the zone during the specified heating
SizingPeriod:DesignDay](page-008.html#sizingperioddesignday)
and cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered it is used as the maximum supply air
flow rate into the zone. It will be multiplied by the Supply
Air Sizing Factor and by zone multipliers. The
[HVACTemplate:System:VAV object that is referenced also allows
the specification of supply air flow. If the value is
specified at the system level it will scale the zone values to
match. The units are in m3/s.
Field: Zone
Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone
design heating air flow rate and load will be multiplied by
the number input in this field when Supply Air Maximum Flow
Rate is autosized. If this field is left blank, the Heating
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone
Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone
design cooling air flow rate and load will be multiplied by
the number input in this field when Supply Air Maximum Flow
Rate is autosized. If this field is left blank, the Cooling
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone
Minimum Air Flow Method[LINK]
This field is used to select how the program will determine
the minimum flow rate to the zone while the system is
operating. There are three choices for selecting how the
minimum flow rate is specified: Constant, FixedFlowRate, and
Scheduled. If Constant is entered, then the program will use
the value for the constant minimum air flow fraction entered
in the following field. If FixedFlowRate is entered, then the
program will use the value entered in the field below called
Fixed Minimum Air Flow Rate. If Scheduled is entered, then the
program will obtain the value for minimum flow fraction from
the schedule named in the field below called Minimum Air Flow
Fraction Schedule Name.
Field:
Constant Minimum Air Flow Fraction[LINK]
The minimum flow rate to the zone while the system is
operating, specified as a fraction of the maximum air flow
rate. The minimum zone fraction is normally specified to meet
the minimum ventilation requirement for the occupants. The
reheat coil operates only when the damper is at this minimum
flow rate when Damper Heating Action is set to Normal (the
default). This field is used if the previous field is set to
Constant. If the previous field is set to Scheduled (and the
field Maximum Hot Water or Steam Flow Rate is set to
autosize), then this field is optional and can be used to
separately control the air flow rate used for sizing
normal-action reheat coils. If this field and the following
field have values, the greater of the two is used for
sizing.
Field: Fixed
Minimum Air Flow Rate[LINK]
The minimum flow rate to the zone while the system is
operating, specified as a fixed minimum air flow rate in
meters cubed per second. The minimum air flow rate is normally
specified to meet the minimum ventilation requirement for the
occupants. The reheat coil operates only when the damper is at
this minimum flow rate when Damper Heating Action is set to
Normal (the default). This field is used if the [Zone](../input-output-reference/page-011.html#zone)
Minimum Air Flow Method field is set to FixedFlowRate. If the
[Zone](../input-output-reference/page-011.html#zone)
Minimum Air Flow Method field is set to Scheduled (and the
field Maximum Hot Water or Steam Flow Rate is set to
autosize), then this field is optional and can be used to
separately control the air flow rate used for sizing
normal-action reheat coils. Only one of these two minimum air
flow fields (i.e., this field and the previous field) should
be used at any time. If this field and the previous field have
values, the greater of the two is used for sizing.
Field:
Minimum Air Flow Fraction Schedule Name[LINK]
The name of a schedule that determines the value of the
minimum air flow fraction. The schedule should contain
fractions from 0.0 to 1.0. These values will define the
minimum flow rate to the zone while the system is operating,
specified as a fraction of the maximum air flow rate. The
reheat coil operates only when the damper is at this minimum
flow rate when Damper Heating Action is set to Normal (the
default). This field is used if the previous field is set to
Scheduled. If the previous field is left blank (and the field
Maximum Hot Water or Steam Flow Rate is set to autosize), then
the air flow rate used for sizing normal-action reheat coils
is the average of the minimum and maximum values in this
schedule. The air flow rate used for reheat coil sizing is
reported with other component sizing information as “Reheat
Coil Sizing Air Volume Flow Rate.”
Field: Outdoor Air
Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone),
**or Flow/Person, Flow/Area, Sum,
Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow as the zone design outdoor air flow
rate. Flow/Person means the program will use the
input from the field Outdoor Air Flow per Person and
the maximum occupancy to calculate a zone design outdoor air
flow rate. Flow/Area means the program will use the
input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area to calculated a zone design outdoor air flow
rate. Sum means that the flows calculated from the
fields Outdoor Air Flow per Person, Outdoor Air
Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be added to obtain the zone design outdoor air flow rate.
Maximum means that the maximum flow derived from
Outdoor Air Flow per Person, Outdoor Air Flow per
Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be used for the zone design outdoor air flow rate. The
default is Flow/Person.
DetailedSpecification means that the outdoor air
specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object. These objects are referenced in the Design
Specification Outdoor Air Object Name for Sizing and Design
Specification [Zone](../input-output-reference/page-011.html#zone)
Air Distribution Object Name fields below.
If the air handler serving this zone serves more than one
zone, the total outdoor air flow for the system is the sum of
the zone outdoor air flows if the system outdoor air flow is
autosized. Since the zones share a single outdoor air source,
the amount of outdoor air actually delivered to the zone is
based on the fraction of supply air delivered to the zone to
the total supply air from the system.
Field:
Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone
in cubic meters per second. The default is 0.00944 (20 cfm per
person). An outdoor air flow rate is calculated based on the
total number of people for all [People](../input-output-reference/page-015.html#people)
statements assigned to the zone. Occupancy schedule values are
not applied. This input is used if Outdoor Air Method
is one of Outdoor Air Flow per Person, Sum,
or Maximum.
Field:
Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square
meter of floor area (units are m3/s-m2).
This input is multiplied by the zone area to obtain a flow
rate. This input is used if Outdoor Air Method is
Flow/Area, Sum or Maximum.
Field: Outdoor
Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic
meters per second. This input field is used if Outdoor Air
Method is Flow/Zone, Sum or
Maximum.
Field: Reheat Coil Type[LINK]
A reheat coil may be added to the VAV box with this field.
The choices are:
The default choice is None.
Field:
Reheat Coil Availability Schedule Name[LINK]
Leave this field blank if you want the reheat coil to be
available for the entire year to perform heating if called for
by the thermostat. If a schedule name is specified, those
times that the coil is available should be specified as 1.0.
Those times that the coil is not available should have a zero
value in the schedule specified. Please note that this is not
a schedule of when the coil is providing heat but a schedule
of when it can provide heat.
Field: Damper Heating
Action[LINK]
The VAV box flow rate can be controlled in one of two ways
during heating operation:
Under “Normal” operation, the supply air flow into the zone
is the minimum air flow rate of the VAV system during heating,
essentially acting like a constant volume system during
heating. Under “Reverse” the air flow rate through the VAV box
may increase above the minimum air flow when the heating
demand cannot be satisfied unless greater air flow is
provided. The default value is Normal. Reverse action only
applies when Reheat Coil Type is HotWater. For electric reheat
coils, Normal and Reverse behave the same. For more details,
please see the section for [AirTerminal:SingleDuct:VAV:Reheat](../input-output-reference/page-031.html#airterminalsingleductvavreheat).
Control
Fields for Maximum Flow During Reheat:[LINK]
The following two fields are used only when Reheat Coil
Object Type = [Coil:Heating:Water](../input-output-reference/page-042.html#coilheatingwater)
and Damper Heating Action = Reverse. Maximum Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area During Reheat and Maximum Flow Fraction During
Reheat are two optional methods to calculate the maximum
allowable air flow rate during reheat operation. If both are
entered, the greater resulting flow rate is used. If Design
Specification Outdoor Air Object Name is also specified, it
may increase this limit to meet the outdoor air flow rate
requirement. At no time will the maximum flow rate calculated
here exceed the value for Maximum Air Flow Rate. This limit is
active only when the zone thermostat requests heating and the
VAV box damper is reverse acting.
Field:
Maximum Flow per Zone Floor Area During Reheat[LINK]
This factor (m3/s-m2) is multiplied
by the zone area, to determine the maximum volume flow rate
(m3/s) allowed during reheat operation (see
detailed explanation above). This field is autocalculatable.
If autocalculate is selected, the value is set to 0.002032
m3/s-m2 (0.4 cfm/ft2). If
this field and the following field are entered, the greater of
the two inputs is used. If this field and the following field
are left blank, the maximum flow will not be limited.
Field:
Maximum Flow Fraction During Reheat[LINK]
This fraction is multiplied by the Maximum Air Flow Rate to
determine the maximum volume flow rate (m3/s)
allowed during reheat operation (see detailed explanation
above). This field is autocalculatable. If autocalculate is
selected, the value is set to 0.002032
m3/s-m2 (0.4 cfm/ft2)
multiplied by the zone floor area divided by the Maximum Air
Flow Rate. If this field and the previous field are entered,
the greater of the two inputs is used. If this field and the
previous field are left blank, the maximum flow will not be
limited.
Field: Maximum
Reheat Air Temperature[LINK]
This field specifies the maximum allowable supply air
temperature (°C) leaving the reheat coil in a VAV terminal
unit during heating operation. If left blank, there is no
limit, and the supply air temperature to the space may become
unrealistically high during heating operation. If unknown, a
value of 35C (95F) is recommended. There is no default in
order to maintain consistency with prior results.
Field:
Design Specification Outdoor Air Object Name for Control[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object. When this field is used, the terminal unit will
increase flow as needed to meet this outdoor air requirement.
If Outdoor Air Flow per Person is non-zero, then the outdoor
air requirement will be computed based on the current number
of occupants in the zone. At no time will the supply air flow
rate exceed the value for Maximum Air Flow Rate. If this field
is blank, then the terminal unit will not be controlled for
outdoor air flow. See documentation for the zone HVAC outdoor
air object for further information (Ref [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object).
Note that this field is used only for specifying the design
outdoor air flow rate used for controlling the terminal unit
air flow rate. The field Design Specification Outdoor Air
Object Name for Sizing (see below) is used to specify the
design outdoor air flow rate.
Field: Supply Plenum
Name[LINK]
This field allows the user to specify a supply plenum which
serves only this zone. The plenum zone is added to the supply
air path after the system splitter or system-level supply
plenum and before the zone terminal unit. Set to blank if no
[AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
is to be modeled. If a [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
is modeled, it must be modeled as a zone with surfaces, and
the name of the plenum zone should be entered here.
Field: Return Plenum
Name[LINK]
This field allows the user to specify a return plenum which
serves only this zone. The plenum zone is added to the return
air path immediately after the zone and before the system
mixer or system-level return plenum. Set to blank if no zone
return plenum is to be modeled. If a zone return plenum is
modeled, it must be modeled as a zone with surfaces, and the
name of the plenum zone should be entered here.
Field: Baseboard
Heating Type[LINK]
This field specifies the availability of thermostatically
controlled baseboard heat in this zone. The choices are:
The default choice is None.
Field:
Baseboard Heating Availability Schedule Name[LINK]
Leave this field blank if you want the baseboard heating to
be available for the entire year to perform heating if called
for by the thermostat. If a schedule name is specified, those
times that the baseboard heating is available should be
specified as 1.0. Those times that the basebaord heating is
not available should have a zero value in the schedule. Please
note that this is not a schedule of when the baseboard is
providing heat but a schedule of when it can provide heat.
Field: Baseboard
Heating Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the baseboard heating can
deliver in Watts. Note that EnergyPlus autosizing will
autosize the baseboard heating to meet the full heating load
of the zone, regardless of the heating capability of the VAV
air handling system. The baseboard heating will be set to
heating priority 2, which means it will meet any remaining
heating load not met by the VAV system. Prior to v7.1, the
capacity was only applied to electric baseboard. Starting with
v7.1, the capacity will be used for both hot water and
electric baseboard.
This field selects the method for specifying the
cooling design supply air temperature.
SupplyAirTemperature means that the field
Zone](page-011.html#zone) Cooling Design Supply Air
Temperature will be used for sizing the zone cooling design
air flow rate and the cooling coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used.
SystemSupplyAirTemperature means that the Cooling
Design Supply Air Temperature from the template VAV system
serving this zone will be used (Ref. [HVACTemplate:System:VAV
or HVACTemplate:System:PackagedVAV). The default is
SystemSupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
cooling design air flow rate calculation and cooling coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is 12.8°C.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design
supply air temperature and the zone air temperature in degrees
Celsius for the zone cooling design air flow rate calculation
and cooling coil sizing. The absolute value is used, so the
sign may be positive or negative. This field is used only when
[Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 11.11
deltaC.
This field selects the method for specifying the
heating design supply air temperature.
SupplyAirTemperature means that the field Heating
Coil Design Setpoint will be used for sizing the zone heating
design air flow rate and the heating coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
heating design air flow rate calculation and heating coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
50oC.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and zone air temperature in degrees Celsius
for the zone heating design air flow rate calculation and
heating coil sizing. The absolute value is used, so the sign
may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 30 deltaC.
Field:
Design Specification Outdoor Air Object Name for Sizing[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object which specifies the design outdoor air flow rate for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification. Note that this field is used
only for specifying the design outdoor air flow rate used for
sizing. The field Design Specification Outdoor Air Object
Name for Sizing (see above) is used to actively control
the VAV terminal air flow rate.
Field:
Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object which specifies the air distribution effectiveness for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:VAV,
SPACE1-1, !- Zone Name
VAV Sys 1, !- Template VAV System Name
All Zones, !- Template Thermostat Name
autosize, !- Supply Air Maximum Flow Rate {m3/s}
, !- Zone Heating Sizing Factor
, !- Zone Cooling Sizing Factor
Constant, !- Zone Minimum Air Flow Input Method
0.3, !- Constant Minimum Air Flow Fraction
, !- Fixed Minimum Air Flow Rate {m3/s}
, !- Minimum Air Flow Fraction Schedule Name
flow/person, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow Rate per Person {m3/s}
0.0, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
0.0, !- Outdoor Air Flow Rate per Zone {m3/s}
HotWater, !- Reheat Coil Type
, !- Reheat Coil Availability Schedule Name
Reverse, !- Heating Damper Action
, !- Maximum Flow per Zone Floor Area During Reheat {m3/s-m2}
, !- Maximum Flow Fraction During Reheat
, !- Maximum Reheat Air Temperature
, !- Design Specification Outdoor Air Object Name for Control
, !- Supply Plenum Name
, !- Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule Name
autosize; !- Baseboard Heating Capacity {W}
SystemSupplyAirTemperature, !- Zone Cooling Design Supply Air . . . Input Method
, !- Zone Cooling Design Supply Air Temperature {C]
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC]
SupplyAirTemperature, !- Zone Heating Design Supply Air Temperature Input Method
50.0, !- Zone Heating Design Supply Air Temperature {C]
, !- Zone Heating Design Supply Air Temperature Difference {deltaC]
, !- Design Specification Outdoor Air Object Name for Sizing
; !- Design Specification Zone Air Distribution Object Name
HVACTemplate:Zone:VAV:FanPowered[LINK]
This object simulates the zone portion of a variable air
volume HVAC configuration with a series or parallel fan
powered terminal unit (also know as a powered induction unit
or PIU) and several different heating options. Multiple HVACTemplate:Zone:VAV
or HVACTemplate:Zone:VAV:FanPowered
objects are usually specified for each HVACTemplate:System:VAV
object. Reheat is specified at the zone level.
The series powered induction unit is an air system terminal
unit that mixes varying amounts of secondary (recirculated)
air and primary (conditioned supply) air to produce a fixed
flow of air to a zone. The unit contains a small fan that acts
to induce the secondary air and a heating coil for heating the
mixed secondary and primary air. The fan runs at a constant
volume flow rate whenever the unit is on (and the fan’s
availability schedule is on or it is activated by an
availability manager). With HVACTemplate:Zone:VAV:FanPowered,
the secondary fan will operate according to the Availability
Schedule and Night Cycle Control specified in the HVACTemplate:System:VAV
it is served by.) The fan is downstream of the primary and
secondary air inlets. The variable mixing is accomplished by a
damper in the unit’s primary air supply inlet duct. This
damper can move from fully open (100% primary air. 0%
secondary air) to a minimum stop that is specified in the
input description. At full cooling the damper will be fully
open. At minimum cooling and for heating the damper will be at
the minimum stop and the secondary air flow will be at its
maximum. Reference object [AirTerminal:SingleDuct:SeriesPIU:Reheat](../input-output-reference/page-031.html#airterminalsingleductseriespiureheat)
for more details.
The parallel powered induction unit is an air system
terminal unit that mixes varying amounts of secondary
(recirculated) air and primary (conditioned supply) air to
produce a variable total flow of air to a zone. The unit
contains a small fan that acts to induce the secondary air and
a heating coil for heating the mixed secondary and primary
air. The secondary and primary air streams enter the unit in
parallel. The fan sits in the secondary air stream and runs
only when the primary air flow is below the Parallel Fan On
Flow Fraction and the fan’s availability schedule is on or it
is activated by an availability manager. With HVACTemplate:Zone:VAV:FanPowered,
the secondary fan will operate according to the Availability
Schedule and Night Cycle Control specified in the HVACTemplate:System:VAV
it is served by.). The primary air inlet contains a damper
that can move from fully open (maximum primary air) to a
minimum stop (minimum primary air). At full cooling load the
primary air damper is fully open and the fan is off. The
primary air flow is at maximum and there is little or no
secondary air flow. As the cooling load decreases, the primary
air damper gradually closes and the secondary air flow remains
close to zero. At some point, usually when the primary air
flow has reached the minimum, the fan switches on and
secondary air is induced. The heating coil will switch on as
needed to meet any heating demand. Reference object [AirTerminal:SingleDuct:ParallelPIU:Reheat](../input-output-reference/page-031.html#airterminalsingleductparallelpiureheat)
for more details.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template VAV
System Name[LINK]
Enter the name of the HVACTemplate:System:VAV
object serving this zone.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:* objects can reference the
same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
Field:
Primary Supply Air Maximum Flow Rate[LINK]
In a fan powered VAV terminal unit, the primary air flow is
the air supplied by the central air handler. By entering
Autosize, the maximum primary supply air flow rate is
automatically determined for the zone based on the loads
experienced by the zone during the specified and cooling
SizingPeriod:DesignDay](page-008.html#sizingperioddesignday).
If a value is entered it is used as the maximum supply air
flow rate into the zone. It will be multiplied by the Supply
Air Sizing Factor and by zone multipliers. The
[HVACTemplate:System:VAV object that is referenced also allows
the specification of supply air flow. If the value is
specified at the system level it will scale the zone values to
match. The units are in m3/s.
Field: Zone
Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone
design heating air flow rate and load will be multiplied by
the number input in this field when Primary Supply Air Maximum
Flow Rate is autosized. If this field is left blank, the
Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone
Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone
design cooling air flow rate and load will be multiplied by
the number input in this field when Primary Supply Air Maximum
Flow Rate is autosized. If this field is left blank, the
Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field:
Primary Supply Air Minimum Flow Fraction[LINK]
Enter the fraction that the VAV box can reduce to based on
the primary supply air maximum flow rate. This field may be
sized automatically by entering Autosize.
Field:
Secondary Supply Air Maximum Flow Rate[LINK]
In a fan powered VAV terminal unit, the secondary air flow
is the air taken from the zone by the terminal unit fan. By
entering Autosize, the maximum secondary supply air flow rate
is automatically determined for the zone based on the loads
experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered, it will be multiplied by the Supply Air
Sizing Factor and by zone multipliers. The units are in
m3/s.
Field: Flow Type[LINK]
This field specifies the type of fan powered unit (PIU).
The choices for this field are:
See descriptions of these configurations in the general
description for this object, above. For both types, the
secondary fan will run according to the System Availability
Schedule and Night Cycle Control specified in the HVACTemplate:System:VAV
which serves this terminal unit (see Template VAV System
above). For Parallel PIU, there is an additional secondary fan
control based on the primary air flow fraction (see Parallel
Fan On Flow Fraction below).
Field: Parallel
Fan On Flow Fraction[LINK]
For parallel PIUs, this field specifies the fraction of the
primary air flow at which fan turns on. In the parallel PIU
the fan operation is intermittent. If the primary air flow is
above this fraction of the maximum, the fan is off. Otherwise
the secondary fan will run according to the System
Availability Schedule and Night Cycle Control specified in the
HVACTemplate:System:VAV
which serves this terminal unit. This field does not apply to
series PIUs.
Field: Outdoor Air
Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone),
**or Flow/Person, Flow/Area, Sum,
Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow as the zone design outdoor air flow
rate. Flow/Person means the program will use the
input from the field Outdoor Air Flow per Person and
the maximum occupancy to calculate a zone design outdoor air
flow rate. Flow/Area means the program will use the
input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area to calculated a zone design outdoor air flow
rate. Sum means that the flows calculated from the
fields Outdoor Air Flow per Person, Outdoor Air
Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be added to obtain the zone design outdoor air flow rate.
Maximum means that the maximum flow derived from
Outdoor Air Flow per Person, Outdoor Air Flow per
Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be used for the zone design outdoor air flow rate. The
default is Flow/Person.
DetailedSpecification means that the outdoor air
specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object. These objects are referenced in the Design
Specification Outdoor Air Object Name and Design Specification
[Zone](../input-output-reference/page-011.html#zone)
Air Distribution Object Name fields below.
If the air handler serving this zone serves more than one
zone, the total outdoor air flow for the system is the sum of
the zone outdoor air flows if the system outdoor air flow is
autosized. Since the zones share a single outdoor air source,
the amount of outdoor air actually delivered to the zone is
based on the fraction of supply air delivered to the zone to
the total supply air from the system.
Field:
Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone
in cubic meters per second. The default is 0.00944 (20 cfm per
person). An outdoor air flow rate is calculated based on the
total number of people for all [People](../input-output-reference/page-015.html#people)
statements assigned to the zone. Occupancy schedule values are
not applied. This input is used if Outdoor Air Method
is one of Outdoor Air Flow per Person, Sum,
or Maximum.
Field:
Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square
meter of floor area (units are m3/s-m2).
This input is multiplied by the zone area to obtain a flow
rate. This input is used if Outdoor Air Method is
Flow/Area, Sum or Maximum.
Field: Outdoor
Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic
meters per second. This input field is used if Outdoor Air
Method is Flow/Zone, Sum or
Maximum.
Field: Reheat Coil Type[LINK]
A reheat coil may be added to the VAV box with this field.
The choices are:
The default choice is Electric.
Field:
Reheat Coil Availability Schedule Name[LINK]
Leave this field blank if you want the reheat coil to be
available for the entire year to perform heating if called for
by the thermostat. If a schedule name is specified, those
times that the coil is available should be specified as 1.0.
Those times that the coil is not available should have a zero
value in the schedule specified. Please note that this is not
a schedule of when the coil is providing heat but a schedule
of when it can provide heat.
Field: Fan Total
Efficiency[LINK]
Enter the total efficiency of the zone induction fan. This
is the ratio of the power delivered to the air to the
electrical input power at maximum flow. This is also the
product of the fan motor efficiency and fan (impeller)
efficiency. The motor efficiency is the power delivered to the
shaft divided by the electrical power input to the motor. The
fan efficiency is the power delivered to the air divided by
the shaft power. The power delivered to the fluid is the mass
flow rate of the air multiplied by the pressure rise divided
by the air density. Must be greater than 0 and less than or
equal to 1.
Field: Fan Delta
Pressure[LINK]
Enter the pressure rise of the zone induction fan in Pa at
full flow and standard conditions. Standard conditions are
considered 20oC at sea level, 101325 Pa.
Field: Fan Motor
Efficiency[LINK]
Enter the shaft power of the zone induction fan divided by
the electrical power consumed. Must be greater than 0 and less
than or equal to 1. Note that the zone fan motor is assumed to
be 100% in the air stream.
Field: Supply Plenum
Name[LINK]
This field allows the user to specify a supply plenum which
serves only this zone. The plenum zone is added to the supply
air path after the system splitter or system-level supply
plenum and before the zone terminal unit. Set to blank if no
[AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
is to be modeled. If a [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
is modeled, it must be modeled as a zone with surfaces, and
the name of the plenum zone should be entered here.
Field: Return Plenum
Name[LINK]
This field allows the user to specify a return plenum which
serves only this zone. The plenum zone is added to the return
air path immediately after the zone and before the system
mixer or system-level return plenum. Set to blank if no zone
return plenum is to be modeled. If a zone return plenum is
modeled, it must be modeled as a zone with surfaces, and the
name of the plenum zone should be entered here.
Field: Baseboard
Heating Type[LINK]
This field specifies the availability of thermostatically
controlled baseboard heat in this zone. The choices are:
The default choice is None.
Field:
Baseboard Heating Availability Schedule Name[LINK]
Leave this field blank if you want the baseboard heating to
be available for the entire year to perform heating if called
for by the thermostat. If a schedule name is specified, those
times that the baseboard heating is available should be
specified as 1.0. Those times that the basebaord heating is
not available should have a zero value in the schedule. Please
note that this is not a schedule of when the baseboard is
providing heat but a schedule of when it can provide heat.
Field: Baseboard
Heating Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the baseboard heating can
deliver in Watts. Note that EnergyPlus autosizing will
autosize the baseboard heating to meet the full heating load
of the zone, regardless of the heating capability of the VAV
air handling system. The baseboard heating will be set to
heating priority 2, which means it will meet any remaining
heating load not met by the VAV system. Prior to v7.1, the
capacity was only applied to electric baseboard. Starting with
v7.1, the capacity will be used for both hot water and
electric baseboard.
This field selects the method for specifying the
cooling design supply air temperature.
SupplyAirTemperature means that the field
Zone](page-011.html#zone) Cooling Design Supply Air
Temperature will be used for sizing the zone cooling design
air flow rate and the cooling coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used.
SystemSupplyAirTemperature means that the Cooling
Design Supply Air Temperature from the template VAV system
serving this zone will be used (Ref. [HVACTemplate:System:VAV
or HVACTemplate:System:PackagedVAV). The default is
SystemSupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
cooling design air flow rate calculation and cooling coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is 12.8°C.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design
supply air temperature and the zone air temperature in degrees
Celsius for the zone cooling design air flow rate calculation
and cooling coil sizing. The absolute value is used, so the
sign may be positive or negative. This field is used only when
[Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 11.11
deltaC.
This field selects the method for specifying the
heating design supply air temperature.
SupplyAirTemperature means that the field Heating
Coil Design Setpoint will be used for sizing the zone heating
design air flow rate and the heating coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
heating design air flow rate calculation and heating coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
50oC.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and zone air temperature in degrees Celsius
for the zone heating design air flow rate calculation and
heating coil sizing. The absolute value is used, so the sign
may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 30 deltaC.
Field: Zone PIU Fan
Schedule Name[LINK]
This is the operating schedule for the zone PIU fan. For a
parallel PIU, the zone fan operates only when the primary air
flow is below the Parallel Fan On Flow Fraction and the [Zone](../input-output-reference/page-011.html#zone)
PIU Fan Schedule is on, or when it is activated by an
availability manager. For a series PIU, the zone fan operates
whenever the [Zone](../input-output-reference/page-011.html#zone)
PIU Fan Schedule is on, or it is activated by an availability
manager. If this field is left blank, the System Availability
Schedule for the HVACTemplate:System serving this zone will be
used.
Field:
Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object which specifies the design outdoor air flow rate for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
Field:
Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object which specifies the air distribution effectiveness for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:VAV:FanPowered,
SPACE1-1, !- Zone Name
VAV Sys 1, !- Template VAV System Name
All Zones, !- Template Thermostat Name
autosize, !- Primary Supply Air Maximum Flow Rate {m3/s}
, !- Zone Heating Sizing Factor
, !- Zone Cooling Sizing Factor
autosize, !- Primary Supply Air Minimum Flow Fraction
autosize, !- Secondary Supply Air Maximum Flow Rate {m3/s}
Series, !- Flow Type
autosize, !- Parallel Fan On Flow Fraction
flow/person, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow Rate per Person {m3/s}
0.0, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
0.0, !- Outdoor Air Flow Rate per Zone {m3/s}
HotWater, !- Reheat Coil Type
, !- Reheat Coil Availability Schedule Name
0.7, !- Fan Total Efficiency
1000, !- Fan Delta Pressure {Pa}
0.9, !- Fan Motor Efficiency
, !- Supply Plenum Name
, !- Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule Name
autosize; !- Baseboard Heating Capacity {W}
SystemSupplyAirTemperature, !- Zone Cooling Design Supply Air . . . Input Method
, !- Zone Cooling Design Supply Air Temperature {C]
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC]
SupplyAirTemperature, !- Zone Heating Design Supply Air Temperature Input Method
50.0, !- Zone Heating Design Supply Air Temperature {C]
, !- Zone Heating Design Supply Air Temperature Difference {deltaC]
, !- Zone PIU Fan Schedule Name
, !- Design Specification Outdoor Air Object Name
; !- Design Specification Zone Air Distribution Object Name
HVACTemplate:Zone:WaterToAirHeatPump[LINK]
This object simulates the zone portion of a water source
heat pump system. Often many HVACTemplate:Zone:WaterToAirHeatPump
objects will be used in a building along with a single HVACTemplate:Plant:MixedWaterLoop
that contains a cooling tower and boiler.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building
zone name used in the ZONE object.
Field: Template
Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat
object. Multiple HVACTemplate:Zone:* objects can reference the
same HVACTemplate:Thermostat
object which makes it easier to revise the thermostat controls
for portions of a building.
When this field is blank, it has a special meaning. A blank
entry means that traditional thermostat objects referencing
the same zone name are used instead of HVACTemplate:Thermostat.
Field: Cooling
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the unit
is operating in cooling mode. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered, it will be multiplied by the Supply Air
Sizing Factor and by zone multipliers. The units are in m3/s.
The default is autosize.
Field: Heating
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the unit
is operating in heating mode. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
If a value is entered, it will be multiplied by the Supply Air
Sizing Factor and by zone multipliers. The units are in m3/s.
The default is autosize.
Field: No Load
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither
cooling nor heating is required (i.e., the coil is off but the
supply air fan operates). This field is only used when the
supply air fan operating mode schedule specifies continuous
fan operation. Values must be greater than or equal to zero,
or this field is autosizable. If the supply air fan operating
mode schedule specifies continuous fan operation and this
value is set to zero or this field is left blank, then the
model assumes that the supply air flow rate when no
cooling/heating is needed is equal to the supply air flow rate
when the cooling or heating coil was last operating (for
cooling operation or heating operation). . By entering
Autosize, the supply air flow rate will be sized to match the
smaller of the Cooling and Heating flow rates. A value entered
in this field will not be multiplied by the sizing
factor or by zone multipliers. It is best to autosize or leave
blank when using zone multipliers. The units are in m3/s. The
default is autosize.
Field: Zone
Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone
design heating air flow rate and load will be multiplied by
the number input in this field when Heating Supply Air Flow
Rate is autosized. If this field is left blank, the Heating
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Zone
Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone
design cooling air flow rate and load will be multiplied by
the number input in this field when Cooling Supply Air Flow
Rate is autosized. If this field is left blank, the Cooling
Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters)
will be used.
Field: Outdoor Air
Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone),
**or Flow/Person, Flow/Area, Sum,
Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow as the zone design outdoor air flow
rate. Flow/Person means the program will use the
input from the field Outdoor Air Flow per Person and
the maximum occupancy to calculate a zone design outdoor air
flow rate. Flow/Area means the program will use the
input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area to calculated a zone design outdoor air flow
rate. Sum means that the flows calculated from the
fields Outdoor Air Flow per Person, Outdoor Air
Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be added to obtain the zone design outdoor air flow rate.
Maximum means that the maximum flow derived from
Outdoor Air Flow per Person, Outdoor Air Flow per
Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
will be used for the zone design outdoor air flow rate. The
default is Flow/Person.
DetailedSpecification means that the outdoor air
specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object. These objects are referenced in the Design
Specification Outdoor Air Object Name and Design Specification
[Zone](../input-output-reference/page-011.html#zone)
Air Distribution Object Name fields below.
Field:
Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone
in cubic meters per second. The default is 0.00944 (20 cfm per
person). An outdoor air flow rate is calculated based on the
total number of people for all [People](../input-output-reference/page-015.html#people)
statements assigned to the zone. Occupancy schedule values are
not applied. This input is used if Outdoor Air Method
is one of Outdoor Air Flow per Person, Sum,
or Maximum.
Field:
Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square
meter of floor area (units are m3/s-m2).
This input is multiplied by the zone area to obtain a flow
rate. This input is used if Outdoor Air Method is
Flow/Area, Sum or Maximum.
Field: Outdoor
Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic
meters per second. This input field is used if Outdoor Air
Method is Flow/Zone, Sum or
Maximum.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. When the fan
operating mode schedule indicates continuous fan operation,
the fan will operate whenever this schedule is 1.0. If the fan
operating schedule indicates cycling fan operation, then fan
will only cycle on as needed to meet a load.
Field:
Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan
operating mode schedule. The supply air fan operating mode may
vary during the simulation based on time-of-day or with a
change of season. Schedule values of 0 denote that the supply
air fan and the heating or cooling coil cycle on and off
together to meet the heating or cooling load (a.k.a. AUTO
fan). Schedule values other than 0 denote that the supply fan
runs continuously while the heating or cooling coil cycles to
meet the load. The keywords Cycling or
Continuous may also be used to specify a single mode
of operation for the entire simulation. The default is
Cycling.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the cooling and heating coils. BlowThrough
models a system where the supply air fan is before the cooling
and heating coils. The default is DrawThrough.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1. The
default is 0.7.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20oC
at sea level, 101325 Pa. The default is 75.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater than 0 and less
than or equal to 1. The default is 0.9.
Field: Cooling Coil
Type[LINK]
Enter the type of cooling coil. There is currently only one
choices for this field, [Coil:Cooling:WaterToAirHeatPump:EquationFit](../input-output-reference/page-042.html#coilcoolingwatertoairheatpumpequationfit).
Field: Cooling
Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm
determine the cooling coil capacity based on the maximum
cooling loads during the cooling design day. If a value is
entered, it represents the full load total cooling capacity,
including both sensible and latent capacity, in watts of the
DX coil unit at rated conditions (26.7C (80F) entering air
dry-bulb temperature, 19.4C (67F) entering air wet-bulb
temperature, and 29.4C (85F) entering water temperature).
Capacity should be the “gross” capacity where the impact of
supply air fan heat is NOT included. The units are in W. The
default is autosize. If a value is specified for this field,
it is recommended that the Cooling Coil Rated Sensible Heat
Ratio also be specified (see below for more details).
Field:
Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine
the sensible heat ratio based on the rated capacity and air
flow rate. Otherwise, enter the value of the ratio of the
sensible capacity divided by total cooling capacity of the DX
cooling coil at rated conditions (26.7C (80F) entering air
dry-bulb temperature, 19.4C (67F) entering air wet-bulb
temperature, and 29.4C (85F) entering water temperature). Both
the sensible and total cooling capacities used to define the
Rated Sensible Heat Ratio (SHR) should be “gross” capacity
where the impact of supply air fan heat is NOT included. The
default is autosize. If the Cooling Coil Rated Capacity is
autosized, this field should also be autosized (any value
specified for Cooling Coil Rate Sensibe Heat Ratio will be
ignored). If the Cooling Coil Rated Capacity has a specified
value, then this field should also have a specified value.
This is because the [Coil:Cooling:WaterToAirHeatPump:EquationFit](../input-output-reference/page-042.html#coilcoolingwatertoairheatpumpequationfit)
object has fields for Rated Total Cooling Capacity and Rated
Sensible Cooling Capacity. If this field is autosized, a
specified value for Cooling Coil Rated Capacity will not be
used when the coil object sensible capacity is autosized.
Field: Cooling Coil
Rated COP[LINK]
Enter the coefficient of performance defined as the gross
cooling coil capacity in watts divided by electrical power
input in watts of the DX cooling coil unit at rated conditions
(26.7C (80F) entering air dry-bulb temperature, 19.4C (67F)
entering air wet-bulb temperature, and 29.4C (85F) entering
water temperature). The input power includes electric power
for the compressor and condenser fan but does not include the
power consumption of the supply air fan. The default is
3.5.
Field: Heat Pump
Heating Coil Type[LINK]
Enter the type of heat pump heating coil. There is
currently only one choices for this field, [Coil:Heating:WaterToAirHeatPump:EquationFit](../input-output-reference/page-042.html#coilheatingwatertoairheatpumpequationfit).
Field:
Heat Pump Heating Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm
determine the heat pump heating coil capacity based on the
maximum heating loads during the heating design day. If a
value is entered, it represents the full load heating
capacity, in watts of the DX heat pump unit at rated
conditions (21.11C (70F) entering air dry-bulb temperature and
21.11C (70F) entering water temperature). Capacity should be
the “gross” capacity where the impact of supply air fan heat
is NOT included. The units are in W. The default is
autosize.
Field: Heat
Pump Heating Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross
heating coil capacity in watts divided by electrical power
input in watts of the DX heating coil unit at rated conditions
(21.11C (70F) entering air dry-bulb temperature and 21.11C
(70F) entering water temperature). The input power includes
electric power for the compressor and condenser fan but does
not include the power consumption of the supply air fan. The
default is 4.2.
Field:
Supplemental Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when supplemental heating is only available
seasonally. The schedule values denote whether the
supplemental heating coil can run during a given time period.
A schedule value of 1.0 indicates that the supplemental
heating coil can be on during a given time period. A value of
zero denotes that the supplemental heating coil cannot be used
during that time period
Field:
Supplemental Heating Coil Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the supplemental heating coil
can deliver in Watts. The default is autosize.
Field: Maximum Cycling
Rate[LINK]
This numeric field contains the maximum on-off cycling rate
for the compressor, which occurs at 50% run time fraction.
Suggested values are shown below (Henderson et al. 1999):
Field: Heat Pump Time
Constant[LINK]
This numeric field contains the time constant for the
cooling coil’s capacity to reach steady state after startup.
Suggested values are shown below (Henderson et al. 1999):
Field: Fraction
of On-Cycle Power Use[LINK]
This numeric field contains the fraction of on-cycle power
use to adjust the part load fraction based on the off-cycle
power consumption due to crankcase heaters, controls, fans,
and etc. Suggested value values are below (Henderson et
al. 1999):
Field: Heat Pump Fan
Delay Time[LINK]
This numeric field contains the time delay in seconds for
the heat pump supply air fan to shut off after compressor
cycle off. This value can be obtained from the manufacturer or
the heat pump catalog. Suggested value is 60 seconds. This
value is disregared at times when the WaterToAirHeatPump’s fan
operating mode schedule value is greater than 0 (i.e.,
continuous fan mode).
Field:
Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir
object if this zone is served by a dedicated outdoor air
system (DOAS). When a Dedicated Outdoor Air System Name is
entered, the outdoor air flow rate for this zone equipment
object (ref. [ZoneHVAC:WaterToAirHeatPump](../input-output-reference/page-032.html#zonehvacwatertoairheatpump))
will be set to zero and the DOAS will provide the ventilation
air to the zone based on the outdoor air specifications in
this object. If this field is blank, then the zone served by
this water-to-air heat pump system will not be served by a
DOAS.
Field:
Supplemental Heating Coil Type[LINK]
Enter the type of supplemental heating coil. The choices
for this field are
The default is Electric.
This field selects the method for specifying the
cooling design supply air temperature.
SupplyAirTemperature means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature will be used for sizing
the zone cooling design air flow rate and the cooling coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
cooling design air flow rate calculation and cooling coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
14oC.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design
supply air temperature and the zone air temperature in degrees
Celsius for the zone cooling design air flow rate calculation
and cooling coil sizing. The absolute value is used, so the
sign may be positive or negative. This field is used only when
[Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 11.11
deltaC.
This field selects the method for specifying the
heating design supply air temperature.
SupplyAirTemperature means that the field Heating
Coil Design Setpoint will be used for sizing the zone heating
design air flow rate and the heating coil.
TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Difference will be used.
The default is SupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
heating design air flow rate calculation and heating coil
sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
SupplyAirTemperature. The default is
50oC.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and zone air temperature in degrees Celsius
for the zone heating design air flow rate calculation and
heating coil sizing. The absolute value is used, so the sign
may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method is
TemperatureDifference. The default is 30 deltaC.
Field: Heat Pump
Coil Water Flow Mode[LINK]
This field specifies the way in which water flow through
the heat pump coils will be modeled. For this template,
WatertoAirHeatPump:EquationFit coil objects are generated and,
therefore, there are three options:
- Cycling
- Constant
- CyclingOnDemand
Cycling varies water flow through the coil
based on the heat pump Part Load Ratio. This control method is
appropriate for modeling heat pumps that are outfitted with a
soleniod valve which allows water to flow through the coil
only when the compressor is active. This is the
default for EnergyPlus V8 and later.
Constant provides a constant water flow
regardless of heat pump operation. Remember that EnergyPlus
has two coils (a heating coil and a cooling coil) to
approximate the operation of one coil that can operate in
either heating mode or cooling mode. Therefore, when the water
flow mode is constant, there will be full flow through either
the heating coil or the cooling coil, but not both at the same
time.
ConstantOnDemand provides full flow
through the coil whenever there is a load. When there is no
load, there is zero flow through the coil. This control
strategy represents the way EnergyPlus modeled heat pump water
flow prior to [Version](../input-output-reference/page-006.html#version)
8.
Field:
Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair)
object which specifies the design outdoor air flow rate for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
Field:
Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution)
object which specifies the air distribution effectiveness for
the zone. This field is used only when Outdoor Air Method
= DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:WaterToAirHeatPump,
SPACE1-1, !- Zone Name
All Zones, !- Template Thermostat Name
autosize, !- Cooling Supply Air Flow Rate {m3/s}
autosize, !- Heating Supply Air Flow Rate {m3/s}
, !- No Load Supply Air Flow Rate {m3/s}
, !- Zone Heating Sizing Factor
, !- Zone Cooling Sizing Factor
Flow/Person, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow Rate per Person {m3/s}
, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2}
, !- Outdoor Air Flow Rate per Zone {m3/s}
, !- System Availability Schedule Name
Cycling, !- Supply Fan Operating Mode Schedule Name
DrawThrough, !- Supply Fan Placement
0.7, !- Supply Fan Total Efficiency
75, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
Coil:Cooling:WaterToAirHeatPump:EquationFit, !- Cooling Coil Type
autosize, !- Cooling Coil Rated Capacity {W}
autosize, !- Cooling Coil Rated Sensible Heat Ratio
3, !- Cooling Coil Rated COP
Coil:Heating:WaterToAirHeatPump:EquationFit, !- HPump Heating Coil Type
autosize, !- Heat Pump Heating Coil Rated Capacity {W}
2.75, !- Heat Pump Heating Coil Rated COP
, !- Supplemental Heating Coil Availability Schedule Name
autosize, !- Supplemental Heating Coil Capacity {W}
2.5, !- Maximum Cycling Rate {cycles/hr}
60, !- Heat Pump Time Constant {s}
0.01, !- Fraction of On-Cycle Power Use
60, !- Heat Pump Fan Delay Time {s}
, !- Dedicated Outdoor Air System Name
Electric, !- Supplemental Heating Coil Type
SupplyAirTemperature, !- Zone Cooling Design Supply Air Temperature Input Method
14.0, !- Zone Cooling Design Supply Air Temperature {C]
, !- Zone Cooling Design Supply Air Temperature Difference {deltaC]
SupplyAirTemperature, !- Zone Heating Design Supply Air Temperature Input Method
50.0, !- Zone Heating Design Supply Air Temperature {C]
, !- Zone Heating Design Supply Air Temperature Difference {deltaC]
, !- Design Specification Outdoor Air Object Name
!- Design Specification Zone Air Distribution Object Name
HVACTemplate:System:Unitary[LINK]
This object simulates the system portion of a constant
volume direct-expansion based HVAC configuration with several
different heating options. Often a single HVACTemplate:Zone:Unitary
object will be used with a single HVACTemplate:System:Unitary
object to simulate single zone direct-expansion based air
conditioning systems. In addition, multiple HVACTemplate:Zone:Unitary
objects may appear that all reference the same HVACTemplate:System:Unitary
object in a multiple zone version. For a multizone system,
only one zone is specified as the control zone. Direct
expansion includes single packaged rooftop systems commonly
seen in commercial buildings and split systems commonly seen
in residential buildings.
Enter a name for the HVACTemplate:System:Unitary
object. This name is used in the HVACTemplate:Zone:Unitary
object to reference this system.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. If the “Supply
Fan Operating Mode” (see below) is set to Cycling, then this
is the supply fan operating schedule. If the fan mode is
Cycling this is not a schedule of when the system is providing
heating, cooling or air flow but a schedule of when it can
provide either heating, cooling, or air flow.
Field:
Control Zone or Thermostat Location Name[LINK]
Enter the name of the HVACTemplate:Zone:Unitary
object that contains the thermostat. While multiple HVACTemplate:Zone:Unitary
objects can be part of a HVACTemplate:System:Unitary
system, only one of the zones contains a thermostat that
controls heating and cooling operation. For a single zone
system, this field should contain the name of that zone.
Field: Supply Fan
Maximum Flow Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to
the sum of the zone air flow rates. If a value is entered here
for the maximum air-flow rate, it is the upper limit on system
flow, even if the zone level air flow inputs sum to a greater
value. This flow rate will not be multiplied by a
sizing factor or by zone multipliers. If using zone
multipliers a value entered here must be large enough to serve
the multiplied zones. The units are m3/s.
Field:
Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan
operating mode schedule. The supply air fan operating mode may
vary during the simulation based on time-of-day or with a
change of season. Schedule values of 0 denote that the supply
air fan and the heating or cooling coil cycle on and off
together to meet the heating or cooling load (a.k.a. AUTO
fan). Schedule values other than 0 denote that the supply fan
runs continuously while the heating or cooling coil cycles to
meet the load. The keywords Cycling or
Continuous may also be used to, specify a single mode
of operation for the entire simulation. The default is
Cycling.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20oC
at sea level, 101325 Pa.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater than 0 and less
than or equal to 1.
Field:
Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the
air stream. A value of 0 means that the motor is completely
outside the air stream. A value of 1 means that all of the
motor heat will go into the air stream and act to cause a
temperature rise. Must be between 0 and 1.
Field: Cooling Coil
Type[LINK]
Enter the type of cooling coil. The choices for this field
are:
Set this value to “SingleSpeedDX” if you want to simulate a
system that provides cooling. You may set this value to “None”
if no cooling is desired. The default value is SingleSpeedDX.
Future versions may have additional cooling coil types.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when cooling is only available seasonally. A
schedule value of 1.0 indicates that the cooling coil can be
on during a given time period. A value of zero denotes that
the cooling coil cannot be used during that time period.
Field:
Cooling Design Supply Air Temperature[LINK]
Enter the cooling supply air temperature in °C to be used
for sizing the cooling coil and zone supply air flow rates.
The default is 12.8°C.
Field: Cooling Coil
Capacity[LINK]
Enter autosize to let the automatic sizing algorithm
determine the cooling coil capacity based on the maximum
cooling loads during the cooling design day. If a value is
entered, it represents the full load cooling capacity,
including both sensible and latent capacity, in watts of the
DX coil unit at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Capacity should be the “gross”
capacity where the impact of supply air fan heat is NOT
included. The units are in W.
Field:
Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine
the sensible heat ratio based on the rated capacity and air
flow rate. Otherwise, enter the value of the ratio of the
sensible capacity divided by total cooling capacity of the DX
cooling coil at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Both the sensible and total
cooling capacities used to define the Rated Sensible Heat
Ratio (SHR) should be “gross” capacity where the impact of
supply air fan heat is NOT included.
Field: Cooling Coil
Rated COP[LINK]
Enter the coefficient of performance defined as the gross
cooling coil capacity in watts divided by electrical power
input in watts of the DX cooling coil unit at rated
conditions. Rated conditions are air entering the cooling coil
at the maximum supply air flow rate at 26.7°C drybulb/19.4°C
wetbulb with air entering the outdoor condenser coil at 35°C
drybulb. The input power includes electric power for the
compressor and condenser fan but does not include the power
consumption of the supply air fan.
Field: Heating Coil
Type[LINK]
Enter the type of heating used in the unitary system. The
choices for this field are
Field:
Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when heating is only available seasonally. The
schedule values denote whether the heating coil can run during
a given time period. A schedule value of 1.0 indicates that
the heating coil can be on during a given time period. A value
of zero denotes that the heating coil cannot be used during
that time period
Field:
Heating Design Supply Air Temperature[LINK]
Enter the heating supply air temperature in °C to be used
for sizing the heating coil and zone supply air flow rates.
The default is 50°C.
Field: Heating Coil
Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the coil can deliver in
Watts.
Field: Gas
Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent.
A burner that is 80% efficient would have an entry of 0.8
here, which is the default
Field:
Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
heating coil operation, such as a combustion fan. The units
are in W.
Field: Maximum
Outdoor Air Flow Rate[LINK]
Enter autosize or a value for the maximum amount of outdoor
air flow into the unit when the economizer is operating.
Autosize means that 100% of the full supply flow may be taken
from outdoor air. If a value is entered, it is used instead of
the autosize value. The units are in m3/s. That is, the
entered value is used to define the Maximum Outdoor Air Flow
Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template.
Field: Minimum
Outdoor Air Flow Rate[LINK]
Enter autosize or the value for the minimum amount of
outdoor air that can enter the unit and be distributed to the
zones. Usually this is set to autosize and the value is
calculated by the outdoor air requirements of each zone. If a
value is entered it overrides the outdoor air specification
from the zone level. The units are in m3/s. Note if heat
recovery is specified (see Heat Recovery Type below), then a
value must be entered in this field, because heat recovery
equipment is not yet autosizable. That is, the entered value
is used to define the Minimum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template.
Field:
Minimum Outdoor Air Schedule Name[LINK]
Leave this field blank if you want the minimum outdoor air
to be the same for all hours in the entire year. If a schedule
name is specified, values are decimal fractions (0.0 – 1.0)
that multiply the minimum outdoor air flow rate. This schedule
is useful for reducing the outdoor air flow rate to zero
during unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
- ‘FixedDryBulb’
- ‘DifferentialDryBulb’
- ‘FixedEnthalpy’
- ‘DifferentialEnthalpy’
- ‘ElectronicEnthalpy’ (i.e., humidity ratio curve
strategy)
- ‘FixedDewPointAndDryBulb’
- ‘DifferentialDryBulbAndEnthalpy’
- ‘NoEconomizer’
Choosing NoEconomizer means the economizer
will not operate and the outdoor airflow rate will be at the
minimum for the entire simulation.
Choosing FixedDryBulb means the economizer
will set the outdoor airflow rate at minimum if the outdoor
air temperature is higher than a specified dry-bulb
temperature limit.
Choosing DifferentialDryBulb will trigger
the outdoor airflow to minimum when the dry-bulb temperature
of outdoor air is higher than the dry-bulb temperature of the
return air.
FixedEnthalpy checks the upper limit of
the enthalpy given as a field input against the enthalpy
content of outdoor air and will set the outdoor airflow rate
to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing
but compares the return air enthalpy with the enthalpy of
outdoor air. When the enthalpy of outdoor air is greater than
the enthalpy of the return air, the outdoor air flow rate is
set to minimum.
Choosing ElectronicEnthalpy enables the
simulation to calculate the humidity ratio limit of outdoor
air based on the dry-bulb temperature of outdoor air and a
quadratic/cubic curve, and compare it to the actual outdoor
air humidity ratio. If the actual outdoor humidity ratio is
greater than the calculated humidity ratio limit, then the
outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares
both the outdoor dewpoint temperature and the outdoor dry-bulb
temperature to their specified high limit values. If either
outdoor temperature exceeds the high limit value, the outdoor
airflow rate is set to minimum.
Another option
DifferentialDryBulbAndEnthalpy enables the
control strategy to be based on both the
DifferentialDryBulb and
DifferentialEnthalpy economizer control
strategies.
In addition to all economizer control types listed above,
each control type checks for user-entered values for the upper
limit of dry-bulb temperature, enthalpy limit, humidity ratio
limit and dewpoint limit. The outdoor air flow rate is set to
minimum if any of these entered limits are exceeded.
The default for this field is
NoEconomizer.
Field: Economizer
Lockout[LINK]
Enter one of the following choices for this field:
- NoLockout
- LockoutWithHeating
- LockoutWithCompressor
The default value is NoLockout. The
LockoutWithHeating means that if the packaged
unit is in heating mode, the economizer is locked out – i.e.,
the economizer dampers are closed and there is minimum outdoor
air flow. LockoutWithCompressor means that in
addition to locking out the economizer when the unit is in
heating mode the economizer is locked out when the DX unit
compressor is on. In other words, when the DX coil is off, the
economizer must meet the entire cooling load – it isn’t
allowed to operate in conjunction with the DX cooling coil.
Similarly, when the DX coil is operating, the economizer is
not allowed to operate. The
LockoutWithCompressor option is sometimes
called a “nonintegrated” economizer.
Field:
Economizer Upper Temperature Limit[LINK]
Enter the outdoor air temperature high limit
(oC) for economizer operation. If the outdoor air
temperature is above this limit, the outdoor air flow rate
will be set to the minimum and heat recovery will be enabled
if available. No input or zero in this field means that there
is no outdoor air temperature high limit control.
Field:
Economizer Lower Temperature Limit[LINK]
Enter the outdoor air temperature low limit (oC)
for economizer operation. If the outdoor air temperature is
below this limit, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
temperature low limit control.
Field:
Economizer Upper Enthalpy Limit[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for
economizer operation. If the outdoor air enthalpy is above
this value, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
enthalpy limit control.
Field:
Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC)
for economizer operation. If the outdoor air dewpoint
temperature is above this value, the outdoor airflow rate will
be set to the minimum. This field is required if the
Economizer Control Type ‘FixedDewPointAndDryBulb’ has been
specified. No input (blank) in this field means that there is
no outdoor air dewpoint limit control.
Field: Supply Plenum
Name[LINK]
Set to blank if no supply plenum is to be modeled. If a
supply plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This supply plenum serves all zones on this system. If
any AirLoopHVAC:SupplyPlenums have been specified, the outlet
from the system supply plenum will flow through the [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
to the zone terminal unit.
Field: Return Plenum
Name[LINK]
Set to blank if no return plenum is to be modeled. If a
return plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This return plenum serves all zones on this system. If
any zone return plenums have been specified, the return air
from the zone will flow through the zone return plenum and
then into the system return plenum.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the cooling and heating coils. BlowThrough
models a system where the supply air fan is before the cooling
and heating coils. The default is BlowThrough.
Field: Night Cycle
Control[LINK]
Enter the system behavior during times when the System
Availability Schedule is zero (off). The possible inputs are
StayOff, CycleOnAny, or CycleOnControl[Zone](../input-output-reference/page-011.html#zone).
StayOff means the system will remain off, no matter
how hot or cold the zones may be. CycleOnAny means
that if any zone served by this system has an air temperature
outside the cooling or heating set points the central fan will
turn on even though the System Availability Schedule indicates
the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone)
means the same thing except the availability manager looks at
the temperature in only the zone specified in Night Cycle
Control [Zone](../input-output-reference/page-011.html#zone)
Name. The default is StayOff.
Field: Night
Cycle Control Zone Name[LINK]
For the Night Cycle Control option
CycleOnControlZone enter the name of the control
zone. For other Night Cycle Control options, this field is
ignored.
Field: Heat Recovery
Type[LINK]
Enter the type of air-to-air heat recovery which is
available between the relief air stream and the outdoor air
inlet stream. The choices are:
The default is None. If heat
recovery is specified (i.e., Sensible or
Enthalpy), then a value must be entered in
the Minimum Outdoor Air Flow Rate field, because heat recovery
equipment is not yet autosizable. The entered Minimum Outdoor
Air Flow Rate is used to define the Nominal Supply Air Flow
Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent)
object generated by this template.
Field:
Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is
applied as a constant effectiveness at all conditions. The
valid range is from 0.0 to 1.0, and the default is 0.70.
Field:
Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat
Recovery Type is Enthalpy. This is applied as a
constant effectiveness at all conditions. The valid range is
from 0.0 to 1.0, and the default is 0.65.
Field:
Dehumidification Control Type[LINK]
There are three dehumidification control type options
available:
- None
- CoolReheatHeatingCoil
- CoolReheatDesuperheater
The CoolReheatHeatingCoil option cools beyond the
dry-bulb setpoint as required to meet the humidity setpoint if
the system is capable of doing so. Reheat is provided as
required by the heating coil. In the simulation, two instances
of the heating coil are modeled, one for heating, and one for
reheat. The two coil objects represent the same physical coil
and never operate simultaneously.
The CollReheatDesuperheater option cools beyond
the dry-bulb setpoint as required to meet the humidity
setpoint if the system is capable of doing so. Reheat is
provided by a desuperheater coil (see object [Coil:Heating:Desuperheater](../input-output-reference/page-042.html#coilheatingdesuperheater)).
The default is None which meets the sensible
cooling load only. The humidistat is located in the same zone
that is specified above as the Control [Zone](../input-output-reference/page-011.html#zone)
or Thermostat Location Name.
Field:
Dehumidification Control Zone Name[LINK]
This field is deprecated and will be removed. The
humidistat is located in the same zone that is specified above
as the Control [Zone](../input-output-reference/page-011.html#zone)
or Thermostat Location Name.
Field:
Dehumidification Setpoint[LINK]
This field specifies the zone humidistat setpoint for
dehumidification in percent (0 to 100). The default is
60%.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric)
object. The default is None.
Field:
Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the
system is operating. If a schedule name is specified, it
defines when the humidifier is available. The schedule values
denote whether the humidifier can run during a given time
period. A schedule value of 1.0 indicates that the humidifier
can be on during a given time period. A value of zero denotes
that the humidifier cannot be used during that time period
Field: Humidifier
Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The
humidifier does not currently autosize, so the default is very
large to allow for adequate capacity. The default is 0.000001
m3/s.
Field:
Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity
moisture output. This field can be autosized. When it is
autosized, it is calculated from the rated capacity in kg/s
and the enthalpy rise in J/kg of the feed water from a
reference temperature of liquid water at 20°C to saturated
steam at 100°C.
Field: Humidifier
Control Zone Name[LINK]
This field specifies the zone name where the humidistat is
located for controlling humidification.
Field: Humidifier
Setpoint[LINK]
This field specifies the zone humidistat setpoint for
humidification in percent (0 to 100). The default is 30%.
As shown in an IDF:
HVACTemplate:System:Unitary,
AHU 1, !- Air Handling System Name
FanAndCoilAvailSched, !- System Availability Schedule
EAST ZONE, !- Control Zone Name or Thermostat Location
autosize, !- Supply Fan Max Flow Rate {m3/s}
Fan Mode Schedule, !- Supply Fan Operating Mode Schedule
.7, !- Supply Fan Total Efficiency
600, !- Supply Fan Delta Pressure {Pa}
.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
SingleSspeedDX, !- Cooling Coil Type
FanAndCoilAvailSched, !- Cooling Coil Availability Schedule
14.0, !- Cooling Design Supply Air Temperature {C}
autosize, !- Cooling Coil Capacity {W}
autosize, !- Cooling Coil Rated SHR
3, !- Cooling Coil Rated COP
Gas, !- Heating Coil Type
FanAndCoilAvailSched, !- Heating Coil Availability Schedule
50.0, !- Heating Design Supply Air Temperature {C}
autosize, !- Heating Coil Capacity {W}
.8, !- Gas Heating Coil Efficiency
0, !- Gas Heating Coil Parasitic Electric Load {W}
autosize, !- Maximum Outdoor air Flow Rate {m3/s}
autosize, !- Minimum Outdoor air Flow Rate {m3/s}
, !- Minimum Outdoor air Schedule Name
NoEconomizer, !- Economizer Type
NoLockout, !- Economizer Lockout
, !- Economizer Upper Temperature Limit {C}
, !- Economizer Lower Temperature Limit {C}
, !- Economizer Upper Enthalpy Limit {J/kg}
, !- Economizer Maximum Limit Dewpoint Temperature {C}
, !- Supply Plenum Name
, !- Return Plenum Name
BlowThrough, !- Supply Fan Placement
CycleOnAny, !- Night Cycle Control
, !- Night Cycle Control Zone Name
None, !- Heat Recovery Type
, !- Sensible Heat Recovery Effectiveness
, !- Latent Heat Recovery Effectiveness
None, !- Dehumidification Control Type
, !- Dehumidification Control Zone Name
60, !- Dehumidification Setpoint {percent}
ElectricSteam, !- Humidifier Type
, !- Humidifier Availability Schedule
0.000001, !- Humidifier Rated Capacity {m3/s}
2690, !- Humidifier Rated Electric Power {W}
EAST ZONE, !- Humidifier Control Zone Name
30; !- Humidifier Setpoint {percent}
HVACTemplate:System:UnitaryHeatPump:AirToAir[LINK]
This object simulates the system portion of an air to air
direct-expansion unitary heat pump. Often a single HVACTemplate:Zone:Unitary
object will be used with a single HVACTemplate:System:UnitaryHeatPump:AirToAir
object to simulate single zone direct-expansion based heat
pump systems. In addition, multiple HVACTemplate:Zone:Unitary
objects may appear that all reference the same HVACTemplate:System:UnitaryHeatPump:AirToAir
object in a multiple zone version. For a multizone system,
only one zone is specified as the control zone. The model can
simulate heat pumps seen in commercial buildings and split
systems commonly seen in residential buildings.
Enter a name for the HVACTemplate:System:UnitaryHeatPump:AirToAir
object. This name is used in the HVACTemplate:Zone:Unitary
object to reference this system.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. During times when
the system is available, the supply fan operating mode
controls fan operation. (See “Supply Fan Operating Mode
Schedule Name” below)
Field:
Control Zone or Thermostat Location Name[LINK]
Enter the name of the HVACTemplate:Zone:Unitary
object that contains the thermostat. While multiple HVACTemplate:Zone:Unitary
objects can be part of a HVACTemplate:System:UnitaryHeatPump:AirToAir
system, only one of the zones contains a thermostat that
controls heating and cooling operation. For a single zone
system, this field should contain the name of that zone.
Field: Cooling
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the DX
cooling coil is operating. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
This flow rate will not be multiplied by a sizing
factor or by zone multipliers. If using zone multipliers a
value entered here must be large enough to serve the
multiplied zones. The units are in m3/s. The default is
Autosize.
Field: Heating
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the
heating coil is operating. By entering Autosize, the supply
air flow rate is automatically determined based on the loads
experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday).
This flow rate will not be multiplied by a sizing
factor or by zone multipliers. If using zone multipliers a
value entered here must be large enough to serve the
multiplied zones. The units are in m3/s. The default is
Autosize.
Field: No Load
Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither
cooling nor heating is required (i.e., DX coil and heater are
off but the supply air fan operates). This field is only used
when the supply air fan operating mode schedule specifies
continuous fan operation. Values must be greater than or equal
to zero, or this field is autosizable. If the air
conditioner’s supply air fan operating mode schedule specifies
continuous fan operation and this value is set to zero or this
field is left blank, then the model assumes that the supply
air flow rate when no cooling/heating is needed is equal to
the supply air flow rate when the cooling or heating coil was
last operating (for cooling operation or heating operation).
By entering Autosize, the supply air flow rate will be sized
to match the smaller of the Cooling and Heating flow rates. A
value entered in this field will not be multiplied by
the sizing factor or by zone multipliers. It is best to
autosize or leave blank when using zone multipliers. The units
are in m3/s. The default is Autosize.
Field:
Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan
operating mode schedule. The supply air fan operating mode may
vary during the simulation based on time-of-day or with a
change of season. Schedule values of 0 denote that the supply
air fan and the heating or cooling coil cycle on and off
together to meet the heating or cooling load (a.k.a. AUTO
fan). Schedule values other than 0 denote that the supply fan
runs continuously while the heating or cooling coil cycles to
meet the load. The keywords Cycling or Continuous may also be
used to, specify a single mode of operation for the entire
simulation. The default is Cycling.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the dx cooling/heating coil and before the
supplemental heating coil. BlowThrough models a
system where the supply air fan is before the dx
cooling/heating coil and the supplemental heating coil. The
default is BlowThrough.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1. The
default is 0.7.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20 C at sea
level, 101325 Pa. The default is 600 Pa.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater or equal to the
Supply Fan Total Efficiency and less than or equal to 1. The
default is 0.9.
Field:
Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the
air stream. A value of 0 means that the motor is completely
outside the air stream. A value of 1 means that all of the
motor heat will go into the air stream and act to cause a
temperature rise. Must be between 0 and 1. The default is
1.0.
Field: Cooling Coil
Type[LINK]
Enter the type of cooling coil. There is currently only one
choices for this field,
SingleSpeedDX. Future versions may have additional cooling
coil types.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when cooling is only available seasonally. A
schedule value of 1.0 indicates that the cooling coil can be
on during a given time period. A value of zero denotes that
the cooling coil cannot be used during that time period.
Field:
Cooling Design Supply Air Temperature[LINK]
Enter the cooling supply air temperature in °C to be used
for sizing the cooling coil and zone supply air flow rates.
The default is 12.8°C.
Field: Cooling Coil
Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm
determine the cooling coil capacity based on the maximum
cooling loads during the cooling design day. If a value is
entered, it represents the full load cooling capacity,
including both sensible and latent capacity, in watts of the
DX coil unit at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Capacity should be the “gross”
capacity where the impact of supply air fan heat is NOT
included. The units are in W. The default is Autosize.
Field:
Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine
the sensible heat ratio based on the rated capacity and air
flow rate. Otherwise, enter the value of the ratio of the
sensible capacity divided by total cooling capacity of the DX
cooling coil at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Both the sensible and total
cooling capacities used to define the Rated Sensible Heat
Ratio (SHR) should be “gross” capacity where the impact of
supply air fan heat is NOT included. The default is
Autosize.
Field: Cooling Coil
Rated COP[LINK]
Enter the coefficient of performance defined as the gross
cooling coil capacity in watts divided by electrical power
input in watts of the DX cooling coil unit at rated
conditions. Rated conditions are air entering the cooling coil
at the maximum supply air flow rate at 26.7°C drybulb/19.4°C
wetbulb with air entering the outdoor condenser coil at 35°C
drybulb. The input power includes electric power for the
compressor and condenser fan but does not include the power
consumption of the supply air fan. The default is 3.0.
Field: Heat Pump
Heating Coil Type[LINK]
Enter the type of heat pump heating coil. There is
currently only one choice for this field,
SingleSpeedDXHeatPump.
Field:
Heating Design Supply Air Temperature[LINK]
Enter the heating supply air temperature in °C to be used
for sizing the heating coil and zone supply air flow rates.
The default is 50°C.
Field:
Heat Pump Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heat pump heating
coil to be available anytime the system is operating. If a
schedule name is specified, it defines when the coil is
available. This is most often used when heating is only
available seasonally. A schedule value of 1.0 indicates that
the heat pump heating coil can be on during a given time
period. A value of zero denotes that the heat pump heating
coil cannot be used during that time period.
Field:
Heat Pump Heating Coil Rated Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm
determine the heat pump heating coil capacity based on the
maximum heating loads during the heating design day. If a
value is entered, it represents the full load heating
capacity, in watts of the DX heat pump unit at rated
conditions. Rated conditions are air entering the heat pump
heating coil at the heating supply air flow rate at 21.11°C
drybulb/15.55°C wetbulb with air entering the outdoor coil at
8.33°C drybulb/6.11C wetbulb. Capacity should be the “gross”
capacity where the impact of supply air fan heat is NOT
included. The units are in W. The default is Autosize.
Field: Heat
Pump Heating Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross
heating coil capacity in watts divided by electrical power
input in watts of the DX heating coil unit at rated
conditions. Rated conditions are air entering the heat pump
heating coil at the heating supply air flow rate at 21.11°C
drybulb/15.55°C wetbulb with air entering the outdoor coil at
8.33°C drybulb/6.11C wetbulb. The input power includes
electric power for the compressor and condenser fan but does
not include the power consumption of the supply air fan. The
default is 2.75.
Field:
Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the minimum outdoor dry-bulb
temperature in degrees Celsius for compressor operation. The
compressor will not operate (for DX heating or DX cooling)
when outdoor dry-bulb temperatures fall below this value. The
minimum value must be greater than or equal to -20 °C. The
default value is -8°C.
Field:
Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the outdoor air dry-bulb
temperature above which outdoor coil defrosting is disabled.
The temperature for this input field must be greater than or
equal to 0 C and less than or equal to 7.22 C. If this input
field is left blank, the default value is 5 C.
Field: Heat Pump
Defrost Strategy[LINK]
This alpha field has two choices: ReverseCycle or
Resistive. If the ReverseCycle strategy is
selected, the heating cycle is reversed periodically to
provide heat to melt frost accumulated on the outdoor coil. If
a Resistive defrost strategy is selected, the frost
is melted using an electric resistance heater. If this input
field is left blank, the default defrost strategy is
ReverseCycle.
Field: Heat Pump
Defrost Control[LINK]
This alpha field has two choices: Timed or
OnDemand. If Timed control is selected, the
defrost time period is calculated based on a fixed value or
compressor runtime whether or not frost has actually
accumulated. For Timed defrost control, the
fractional amount of time the unit is in defrost is entered in
the input field “Defrost Time Period Fraction” described
below. If OnDemand defrost control is selected, the
defrost time period is calculated based on outdoor weather
(humidity ratio) conditions. Regardless of which defrost
control is selected, defrost does not occur above the user
specified outdoor temperature entered in the input field “Heat
Pump Defrost Maximum Outdoor Dry-Bulb Temperature” described
above. If this input field is left blank, the default defrost
control is Timed.
Field:
Heat Pump Defrost Time Period Fraction[LINK]
This numeric field defines the fraction of compressor
runtime when the defrost cycle is active, and only applies to
“timed” defrost (see Heat Pump Defrost Control input field
above). For example, if the defrost cycle is active for 3.5
minutes for every 60 minutes of compressor runtime, then the
user should enter 3.5/60 = 0.058333. The value for this input
field must be greater than or equal to 0. If this input field
is left blank, the default value is 0.058333.
Field:
Supplemental Heating Coil Type[LINK]
Enter the type of supplemental heating coil. The choices
for this field are
The default is Electric.
Field:
Supplemental Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the supplemental heating
coil to be available anytime the system is operating. If a
schedule name is specified, it defines when the coil is
available. This is most often used when supplemental heating
is only available seasonally. The schedule values denote
whether the supplemental heating coil can run during a given
time period. A schedule value of 1.0 indicates that the
supplemental heating coil can be on during a given time
period. A value of zero denotes that the supplemental heating
coil cannot be used during that time period
Field:
Supplemental Heating Coil Capacity[LINK]
Enter Autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the supplemental heating coil
can deliver in Watts. The default is Autosize.
Field:
Supplemental Heating Coil Maximum Outdoor Dry-Bulb
Temperature[LINK]
This numeric field defines the outdoor air dry-bulb
temperature above which the supplemental heating coil is
disabled. The temperature for this input field must be less
than or equal to 21 C. If this input field is left blank, the
default value is 21 C.
Field:
Supplemental Gas Heating Coil Efficiency[LINK]
Enter supplemental heating coil gas burner efficiency as a
decimal, not as a percent. A burner that is 80% efficient
would have an entry of 0.8 here, which is the default. This
field applies only if the supplemental heating coil type is
gas.
Field:
Supplemental Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
supplemental heating coil operation, such as a combustion fan.
The units are in W. The default is 0.0. This field applies
only if the supplemental heating coil type is gas.
Field: Maximum
Outdoor Air Flow Rate[LINK]
Enter Autosize or a value for the maximum amount of outdoor
air flow into the unit when the economizer is operating.
Autosize means that 100% of the full supply flow may be taken
from outdoor air. The units are in m3/s. That is, the entered
value is used to define the Maximum Outdoor Air Flow Rate for
the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template.
Field: Minimum
Outdoor Air Flow Rate[LINK]
Enter Autosize or the value for the minimum amount of
outdoor air that can enter the unit and be distributed to the
zones. Usually this is set to autosize and the value is
calculated by the outdoor air requirements of each zone. If a
value is entered it overrides the outdoor air specification
from the zone level. The units are in m3/s. The default is
Autosize. Note if heat recovery is specified (see Heat
Recovery Type below), then a value must be entered in this
field, because heat recovery equipment is not yet autosizable.
That is, the entered value is used to define the Minimum
Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template.
Field:
Minimum Outdoor Air Schedule Name[LINK]
Leave this field blank if you want the minimum outdoor air
to be the same for all hours in the entire year. If a schedule
name is specified, values are decimal fractions (0.0 – 1.0)
that multiply the minimum outdoor air flow rate. This schedule
is useful for reducing the outdoor air flow rate during
unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
- ‘FixedDryBulb’
- ‘DifferentialDryBulb’
- ‘FixedEnthalpy’
- ‘DifferentialEnthalpy’
- ‘ElectronicEnthalpy’ (i.e., humidity ratio curve
strategy)
- ‘FixedDewPointAndDryBulb’
- ‘DifferentialDryBulbAndEnthalpy’
- ‘NoEconomizer’
Choosing NoEconomizer means the economizer
will not operate and the outdoor airflow rate will be at the
minimum for the entire simulation.
Choosing FixedDryBulb means the economizer
will set the outdoor airflow rate at minimum if the outdoor
air temperature is higher than a specified dry-bulb
temperature limit.
Choosing DifferentialDryBulb will trigger
the outdoor airflow to minimum when the dry-bulb temperature
of outdoor air is higher than the dry-bulb temperature of the
return air.
FixedEnthalpy checks the upper limit of
the enthalpy given as a field input against the enthalpy
content of outdoor air and will set the outdoor airflow rate
to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing
but compares the return air enthalpy with the enthalpy of
outdoor air. When the enthalpy of outdoor air is greater than
the enthalpy of the return air, the outdoor air flow rate is
set to minimum.
Choosing ElectronicEnthalpy enables the
simulation to calculate the humidity ratio limit of outdoor
air based on the dry-bulb temperature of outdoor air and a
quadratic/cubic curve, and compare it to the actual outdoor
air humidity ratio. If the actual outdoor humidity ratio is
greater than the calculated humidity ratio limit, then the
outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares
both the outdoor dewpoint temperature and the outdoor dry-bulb
temperature to their specified high limit values. If either
outdoor temperature exceeds the high limit value, the outdoor
airflow rate is set to minimum.
Another option
DifferentialDryBulbAndEnthalpy enables the
control strategy to be based on both the
DifferentialDryBulb and
DifferentialEnthalpy economizer control
strategies.
In addition to all economizer control types listed above,
each control type checks for user-entered values for the upper
limit of dry-bulb temperature, enthalpy limit, humidity ratio
limit and dewpoint limit. The outdoor air flow rate is set to
minimum if any of these entered limits are exceeded.
The default for this field is
NoEconomizer
Field: Economizer
Lockout[LINK]
Enter one of the following choices for this field:
- NoLockout
- LockoutWithHeating
- LockoutWithCompressor
The default value is NoLockout. The
LockoutWithHeating means that if the packaged
unit is in heating mode, the economizer is locked out – i.e.,
the economizer dampers are closed and there is minimum outdoor
air flow. LockoutWithCompressor means that in
addition to locking out the economizer when the unit is in
heating mode the economizer is locked out when the DX unit
compressor is on. In other words, when the DX coil is off, the
economizer must meet the entire cooling load – it isn’t
allowed to operate in conjunction with the DX cooling coil.
Similarly, when the DX coil is operating, the economizer is
not allowed to operate. The
LockoutWithCompressor option is sometimes
called a “nonintegrated” economizer.
Field:
Economizer Maximum Limit Dry-Bulb Temperature[LINK]
Input for this field is the outdoor air temperature high
limit (ºC) for economizer operation. If the outdoor air
temperature is above this limit, the outdoor airflow rate will
be set to the minimum. This field is required if Economizer
Control Type ‘FixedDryBulb’ or ‘FixedDewPointAndDryBulb’ has
been specified. No input (blank) in this field means that
there is no outdoor air temperature high limit control.
Field:
Economizer Maximum Limit Enthalpy[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for
economizer operation. If the outdoor air enthalpy is above
this value, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
enthalpy limit control.
Field:
Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC)
for economizer operation. If the outdoor air dewpoint
temperature is above this value, the outdoor airflow rate will
be set to the minimum. This field is required if the
Economizer Control Type ‘FixedDewPointAndDryBulb’ has been
specified. No input (blank) in this field means that there is
no outdoor air dewpoint limit control.
Field:
Economizer Minimum Limit Dry-Bulb Temperature[LINK]
Enter the outdoor air temperature low limit (C) for
economizer operation. If the outdoor air temperature is below
this limit, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
temperature low limit control.
Field: Supply Plenum
Name[LINK]
Set to blank if no supply plenum is to be modeled. If a
supply plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This supply plenum serves all zones on this system. If
any zone supply plenums have been specified, the outlet from
the system supply plenum will flow through the zone supply
plenum to the zone terminal unit.
Field: Return Plenum
Name[LINK]
Set to blank if no return plenum is to be modeled. If a
return plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This return plenum serves all zones on this system. If
any zone return plenums have been specified, the return air
from the zone will flow through the zone return plenum and
then into the system return plenum.
Field: Night Cycle
Control[LINK]
Enter the system behavior during times when the System
Availability Schedule is zero (off). The possible inputs are
StayOff, CycleOnAny, or CycleOnControl[Zone](../input-output-reference/page-011.html#zone).
StayOff means the system will remain off, no matter
how hot or cold the zones may be. CycleOnAny means
that if any zone served by this system has an air temperature
outside the cooling or heating set points the central fan will
turn on even though the System Availability Schedule indicates
the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone)
means the same thing except the availability manager looks at
the temperature in only the zone specified in Night Cycle
Control [Zone](../input-output-reference/page-011.html#zone)
Name. The default is StayOff.
Field: Night
Cycle Control Zone Name[LINK]
For the Night Cycle Control option
CycleOnControlZone enter the name of the control
zone. For other Night Cycle Control options, this field is
ignored.
Field: Heat Recovery
Type[LINK]
Enter the type of air-to-air heat recovery which is
available between the relief air stream and the outdoor air
inlet stream. The choices are:
The default is None. If heat
recovery is specified (i.e., Sensible or
Enthalpy), then a value must be entered in
the Minimum Outdoor Air Flow Rate field, because heat recovery
equipment is not yet autosizable. The entered Minimum Outdoor
Air Flow Rate is used to define the Nominal Supply Air Flow
Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent)
object generated by this template.
Field:
Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is
applied as a constant effectiveness at all conditions. The
valid range is from 0.0 to 1.0, and the default is 0.70.
Field:
Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat
Recovery Type is Enthalpy. This is applied as a
constant effectiveness at all conditions. The valid range is
from 0.0 to 1.0, and the default is 0.65.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric)
object. The default is None.
Field:
Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the
system is operating. If a schedule name is specified, it
defines when the humidifier is available. The schedule values
denote whether the humidifier can run during a given time
period. A schedule value of 1.0 indicates that the humidifier
can be on during a given time period. A value of zero denotes
that the humidifier cannot be used during that time period
Field: Humidifier
Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The
humidifier does not currently autosize, so the default is very
large to allow for adequate capacity. The default is 0.000001
m3/s.
Field:
Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity
moisture output. This field can be autosized. When it is
autosized, it is calculated from the rated capacity in kg/s
and the enthalpy rise in J/kg of the feed water from a
reference temperature of liquid water at 20°C to saturated
steam at 100°C.
Field:
Humidifier Control Zone Name[LINK]
This field specifies the zone name where the humidistat is
located for controlling humidification.
Field: Humidifier
Setpoint[LINK]
This field specifies the zone humidistat setpoint for
humidification in percent (0 to 100). The default is 30%.
As shown in an IDF:
HVACTemplate:System:UnitaryHeatPump:AirToAir,
Heat Pump 1, !- Name
FanAvailSched, !- System Availability Schedule Name
SPACE1-1, !- Control Zone or Thermostat Location Name
autosize, !- Cooling Supply Air Flow Rate {m3/s}
autosize, !- Heating Supply Air Flow Rate {m3/s}
autosize, !- No Load Supply Air Flow Rate {m3/s}
Cycling, !- Supply Fan Operating Mode Schedule Name
BlowThrough, !- Supply Fan Placement
0.7, !- Supply Fan Total Efficiency
600, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
SingleSpeedDX, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule Name
14, !- Cooling Design Supply Air Temperature {C}
autosize, !- Cooling Coil Capacity {W}
autosize, !- Cooling Coil Rated Sensible Heat Ratio
3, !- Cooling Coil Rated COP
SingleSpeedDXHeatPump, !- Heat Pump Heating Coil Type
, !- Heat Pump Heating Coil Availability Schedule Name
50.0, !- Heating Design Supply Air Temperature {C}
autosize, !- Heat Pump Heating Coil Rated Capacity {W}
2.75, !- Heat Pump Heating Coil Rated COP
-8, !- Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature {C}
5, !- Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature {C}
ReverseCycle, !- Heat Pump Defrost Strategy
Timed, !- Heat Pump Defrost Control
0.058333, !- Heat Pump Defrost Time Period Fraction
Electric, !- Supplemental Heating Coil Type
, !- Supplemental Heating Coil Availability Schedule Name
autosize, !- Supplemental Heating Coil Capacity {W}
21, !- Supplemental Heating Coil Max Outdoor Dry-Bulb Temperature {C}
0.8, !- Supplemental Gas Heating Coil Efficiency
, !- Supplemental Gas Heating Coil Parasitic Electric Load {W}
autosize, !- Maximum Outdoor Air Flow Rate {m3/s}
autosize, !- Minimum Outdoor Air Flow Rate {m3/s}
Min OA Sched, !- Minimum Outdoor Air Schedule Name
DifferentialDryBulb, !- Economizer Type
NoLockout, !- Economizer Lockout
19, !- Economizer Maximum Limit Dry-Bulb Temperature {C}
, !- Economizer Maximum Limit Enthalpy {J/kg}
, !- Economizer Maximum Limit Dewpoint Temperature {C}
4, !- Economizer Minimum Limit Dry-Bulb Temperature {C}
, !- Supply Plenum Name
, !- Return Plenum Name
CycleOnAny, !- Night Cycle Control
, !- Night Cycle Control Zone Name
None, !- Heat Recovery Type
0.7, !- Sensible Heat Recovery Effectiveness
0.65, !- Latent Heat Recovery Effectiveness
None, !- Humidifier Type
, !- Humidifier Availability Schedule Name
0.000001, !- Humidifier Rated Capacity {m3/s}
2690, !- Humidifier Rated Electric Power {W}
, !- Humidifier Control Zone Name
30; !- Humidifier Setpoint {percent}
HVACTemplate:System:VAV[LINK]
This object simulates the system portion of a variable air
volume HVAC configuration with several different heating
options. Multiple HVACTemplate:Zone:VAV
objects are usually specified for each HVACTemplate:System:VAV
object.
Enter a name for the HVACTemplate:System:VAV
object. This name is used in the HVACTemplate:Zone:VAV
object to reference this system.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. Please note that
for this system type, this is a schedule of when the system is
providing air flow.
Field: Supply
Fan Maximum Flow Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to
the sum of the zone air flow rates. If a value is entered here
for the maximum air-flow rate, it is the upper limit on system
flow, even if the zone level air flow inputs sum to a greater
value. This flow rate will not be multiplied by a
sizing factor or by zone multipliers. If using zone
multipliers a value entered here must be large enough to serve
the multiplied zones. The units are m3/s.
Field: Supply Fan
Minimum Flow Rate[LINK]
Enter the minimum supply air volume that may be provided.
This field may be set to autosize. The units are in
m3/s.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20oC
at sea level, 101325 Pa.
Field: Supply Fan
Motor efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater than 0 and less
than or equal to 1.
Field:
Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the
air stream. A value of 0 means that the motor is completely
outside the air stream. A value of 1 means that all of the
motor heat will go into the air stream and act to cause a
temperature rise. Must be between 0 and 1.
Field: Cooling Coil
Type[LINK]
There are two coil types available:
- ChilledWater
- ChilledWaterDetailedFlatModel
ChilledWater uses the COIL:Cooling:Water object
with the DetailedAnalysis option. This is the preferred coil
model for most applications.
ChilledWaterDetailedFlatModel uses the [Coil:Cooling:Water:DetailedGeometry](../input-output-reference/page-042.html#coilcoolingwaterdetailedgeometry)
object. This option is available for special applications. The
default is ChilledWater.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when cooling is only available seasonally. A
schedule value of one indicates that the cooling coil can be
on during a given time period. A value of zero denotes that
the cooling coil cannot be used during that time period.
Field:
Cooling Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the cooling coil is to be
specified, leave this field blank, and the Cooling Coil Design
Setpoint value will be used at all times. If a set point
schedule is to be used for the cooling coil specify the
schedule name here. The schedule should control the supply air
temperature delivered to the zones. For Blow Through fan
placement, this is the leaving air temperature from the
cooling coil. For Draw Through fan placement, this is the
leaving air temperature after the supply fan. The values in
the schedule are in degrees C. This field is ignored if the
Cooling Coil Setpoint Reset Type is something other than None
(see below).
Field: Cooling
Coil Design Setpoint[LINK]
Enter the cooling supply air temperature in C to be used
for sizing the cooling coil and zone supply air flow rates.
The default is 12.8C. If no Cooling Coil Setpoint Schedule or
Cooling Coil Setpoint Reset Type is specified, this value is
used as a constant cooling supply air setpoint
temperature.
Field: Heating Coil
Type[LINK]
The heating coil is located in the supply air stream,
upstream of the cooling coil and after the outdoor air mixing
box. If no central heating coil is used in the VAV system,
then the option “none” should be specified here. Otherwise
this indicates the type of heating coil. It is unlikely that
both a heating coil and a preheat coil would be used at the
same time. The choices for this field are
- HotWater
- Electric
- Gas
- None
The default value is None. Note that the configuration of
HVACTemplate:System:VAV
assumes that there will be reheat coils or baseboard heating
to provide heating control at the zone level. If a heating
coil is specified, the heating and cooling coil setpoint
controls and availability schedules must coordinate to prevent
the coils from opposing each other.
Field:
Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when heating is only available seasonally. The
schedule values denote whether the heating coil can run during
a given time period. A schedule value of one indicates that
the heating coil can be on during a given time period. A value
of zero denotes that the heating coil cannot be used during
that time period
Field:
Heating Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the heating coil is to be
specified, leave this field blank, and the Heating Coil Design
Setpoint value will be used at all times. If a set point
schedule is to be used for the heating coil specify the
schedule name here. The schedule should control the supply air
temperature delivered to the zones. For Blow Through fan
placement, this is the leaving air temperature from the
heating coil. For Draw Through fan placement, this is the
leaving air temperature after the supply fan. The values in
the schedule are in degrees C. This field is ignored if the
Heating Coil Setpoint Reset Type is something other than None
(see below).
Field: Heating
Coil Design Setpoint[LINK]
Enter the heating supply air temperature in C to be used
for sizing the heating coil and zone supply air flow rates. If
no Heating Coil Setpoint Schedule or Heating Coil Setpoint
Reset Type is specified, this value is used as a constant
heating supply air setpoint temperature. The default is
10.0C.
Field: Gas
Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent.
A burner that is 80% efficient would have an entry of 0.8
here, which is the default
Field:
Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
heating operation, such as a combustion fan. The units are in
W.
Field: Preheat Coil Type[LINK]
The preheat coil is located in the outdoor air stream,
upstream of the outdoor air mixing box and tempers the outdoor
air. If no preheat coil is used in the VAV system, then the
option “none” should be specified here. Otherwise this
indicates the type of preheat coil. It is unlikely that both a
heating coil and a preheat coil would be used at the same
time. The choices for this field are
The default value is None. If a preheat coil is specified,
the preheat and cooling coil setpoint controls and
availability schedules must coordinate to prevent the coils
from opposing each other.
Field:
Preheat Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the preheat coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the preheat coil is available.
This is most often used when preheat is only available
seasonally. The schedule values denote whether the preheat
coil can run during a given time period. A schedule value of
1.0 indicates that the preheat coil can be on during a given
time period. A value of zero denotes that the preheat coil
cannot be used during that time period
Field:
Preheat Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the preheat coil is to be
specified, leave this field blank, and the Preheat Coil Design
Setpoint value will be used at all times. If a set point
schedule is to be used for the preheat coil specify the
schedule name here. The schedule should control the leaving
air temperature from the preheat coil. The values in the
schedule are in degrees C.
Field: Preheat
Coil Design Setpoint[LINK]
Enter the preheat supply air temperature in C to be used
for sizing the preheat coil. If no Preheat Coil Setpoint
Schedule is specified, this value is used as a constant
preheat supply air setpoint temperature. The default is
7.2C.
Field: Gas Preheat
Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent.
A burner that is 80% efficient would have an entry of 0.8
here, which is the default
Field:
Gas Preheat Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
heating operation, such as an combustion fan. The units are in
W.
Field: Maximum
Outdoor Air Flow Rate[LINK]
Enter autosize or a value for the maximum amount of outdoor
air flow into the unit when the economizer is operating.
Autosize means that 100% of the full supply flow may be taken
from outdoor air. If a value is entered, it is used instead of
the autosize value. The units are in m3/s. That is, the
entered value is used to define the Maximum Outdoor Air Flow
Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template.
Field: Minimum
Outdoor Air Flow Rate[LINK]
Enter autosize or the value for the minimum amount of
outdoor air that can enter the unit and be distributed to the
zones. Usually this is set to autosize and the value is
calculated by the outdoor air requirements of each zone. If a
value is entered it overrides the outdoor air specification
from the zone level. The units are in m3/s. Note if heat
recovery is specified (see Heat Recovery Type below), then a
value must be entered in this field, because heat recovery
equipment is not yet autosizable. That is, the entered value
is used to define the Minimum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template.
Field: Minimum
Outdoor Air Control Type[LINK]
Choices for this field are FixedMinimum or
ProportionalMinimum. FixedMinimum means that
the minimum outdoor air flow rate is fixed no matter what the
actual system flow rate is. ProportionalMinimum means the
minimum outdoor air flow rate varies in proportion to the
total system air flow rate. The default is
ProportionalMinimum.
Field:
Minimum Outdoor Air Schedule Name Name[LINK]
Leave this field blank if you want the minimum outdoor air
to be the same for all hours in the entire year. If a schedule
name is specified, values are decimal fractions (0.0 – 1.0)
that multiply the minimum outdoor air flow rate. This schedule
is useful for reducing the outdoor air flow rate to zero
during unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
- ‘FixedDryBulb’
- ‘DifferentialDryBulb’
- ‘FixedEnthalpy’
- ‘DifferentialEnthalpy’
- ‘ElectronicEnthalpy’ (i.e., humidity ratio curve
strategy)
- ‘FixedDewPointAndDryBulb’
- ‘DifferentialDryBulbAndEnthalpy’
- ‘NoEconomizer’
Choosing NoEconomizer means the economizer
will not operate and the outdoor airflow rate will be at the
minimum for the entire simulation.
Choosing FixedDryBulb means the economizer
will set the outdoor airflow rate at minimum if the outdoor
air temperature is higher than a specified dry-bulb
temperature limit.
Choosing DifferentialDryBulb will trigger
the outdoor airflow to minimum when the dry-bulb temperature
of outdoor air is higher than the dry-bulb temperature of the
return air.
FixedEnthalpy checks the upper limit of
the enthalpy given as a field input against the enthalpy
content of outdoor air and will set the outdoor airflow rate
to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing
but compares the return air enthalpy with the enthalpy of
outdoor air. When the enthalpy of outdoor air is greater than
the enthalpy of the return air, the outdoor air flow rate is
set to minimum.
Choosing ElectronicEnthalpy enables the
simulation to calculate the humidity ratio limit of outdoor
air based on the dry-bulb temperature of outdoor air and a
quadratic/cubic curve, and compare it to the actual outdoor
air humidity ratio. If the actual outdoor humidity ratio is
greater than the calculated humidity ratio limit, then the
outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares
both the outdoor dewpoint temperature and the outdoor dry-bulb
temperature to their specified high limit values. If either
outdoor temperature exceeds the high limit value, the outdoor
airflow rate is set to minimum.
Another option
DifferentialDryBulbAndEnthalpy enables the
control strategy to be based on both the
DifferentialDryBulb and
DifferentialEnthalpy economizer control
strategies.
In addition to all economizer control types listed above,
each control type checks for user-entered values for the upper
limit of dry-bulb temperature, enthalpy limit, humidity ratio
limit and dewpoint limit. The outdoor air flow rate is set to
minimum if any of these entered limits are exceeded.
The default for this field is
NoEconomizer.
Field: Economizer
Lockout[LINK]
The only choice for this field is
The default value is NoLockout. Future versions may have
additional options.
Field:
Economizer Upper Temperature Limit[LINK]
Enter the outdoor air temperature high limit
(oC) for economizer operation. If the outdoor air
temperature is above this limit, the outdoor air flow rate
will be set to the minimum and heat recovery will be enabled
if available. No input or zero in this field means that there
is no outdoor air temperature high limit control.
Field:
Economizer Lower Temperature Limit[LINK]
Enter the outdoor air temperature low limit (oC)
for economizer operation. If the outdoor air temperature is
below this limit, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
temperature low limit control.
Field:
Economizer Upper Enthalpy Limit[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for
economizer operation. If the outdoor air enthalpy is above
this value, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
enthalpy limit control.
Field:
Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC)
for economizer operation. If the outdoor air dewpoint
temperature is above this value, the outdoor airflow rate will
be set to the minimum. This field is required if the
Economizer Control Type ‘FixedDewPointAndDryBulb’ has been
specified. No input (blank) in this field means that there is
no outdoor air dewpoint limit control.
Field: Supply Plenum
Name[LINK]
Set to blank if no supply plenum is to be modeled. If a
supply plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This supply plenum serves all zones on this system. If
any AirLoopHVAC:SupplyPlenums have been specified, the outlet
from the system supply plenum will flow through the [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum)
to the zone terminal unit.
Field: Return Plenum
Name[LINK]
Set to blank if no return plenum is to be modeled. If a
return plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This return plenum serves all zones on this system. If
any zone return plenums have been specified, the return air
from the zone will flow through the zone return plenum and
then into the system return plenum.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the cooling and heating coils. BlowThrough
models a system where the supply air fan is before the cooling
and heating coils. The default is Draw Through.
Field:
Supply Fan Part-Load Power Coefficients[LINK]
Select the set of generic pre-defined coefficients to use
for the supply fan part-load power consumption. This alpha
field has the following choices:
- InletVaneDampers
- OutletDampers
- VariableSpeedMotor
- ASHRAE90.1-2004Appendix G
- VariableSpeedMotorPressureReset
The default is InletVaneDampers. The resulting
power curves are shown in Figure 146. VAV Supply Fan Part-Load
Power Coefficient Options below. The ASHRAE 90.1-2004 Appendix
G coefficients are from TABLE G3.1.3.15, Method 2. The other
sets of coefficients are from the EnergyPlus Input Output
Reference, Fan Coefficient Values table. The
VariableSpeedMotorPressureReset option is based on
Good Static Pressure Reset VSD Fan from Energy Design
Resources’: Design Guidelines: Advanced Variable Air
Volume (VAV) Systems (EDR_DesignGuidelines_VAV.pdf).
Field: Night Cycle
Control[LINK]
Enter the system behavior during times when the System
Availability Schedule is zero (off). The possible inputs are
StayOff, CycleOnAny, CycleOnControl
Zone](page-011.html#zone) or CycleOnAnyZoneFansOnly.
StayOff means the system will remain off, no matter
how hot or cold the zones may be. CycleOnAny means
that if any zone served by this system has an air temperature
outside the cooling or heating set points the central fan will
turn on even though the System Availability Schedule indicates
the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone)
means the same thing except the availability manager looks at
the temperature in only the zone specified in Night Cycle
Control [Zone](../input-output-reference/page-011.html#zone)
Name. CycleOnAnyZoneFansOnly is the same as
CycleOnAny except that only the zone fans are cycled
on and the central air handler fan is left off (applicable
only if using [HVACTemplate:Zone:VAV:FanPowered in one or more
zones). The default is StayOff.
Field: Night
Cycle Control Zone Name[LINK]
For the Night Cycle Control option Cycle On Control Zone
enter the name of the control zone. For other Night Cycle
Control options, this field is ignored.
Field: Heat Recovery
Type[LINK]
Enter the type of air-to-air heat recovery which is
available between the relief air stream and the outdoor air
inlet stream. The choices are:
The default is None. If heat
recovery is specified (i.e., Sensible or
Enthalpy), then a value must be entered in
the Minimum Outdoor Air Flow Rate field, because heat recovery
equipment is not yet autosizable. The entered Minimum Outdoor
Air Flow Rate is used to define the Nominal Supply Air Flow
Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent)
object generated by this template.
Field:
Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is
applied as a constant effectiveness at all conditions. The
valid range is from 0.0 to 1.0, and the default is 0.70.
Field:
Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat
Recovery Type is Enthalpy. This is applied as a
constant effectiveness at all conditions. The valid range is
from 0.0 to 1.0, and the default is 0.65.
Field: Cooling
Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the cooling
supply air temperature. The choices are:
- None – no reset, use the Cooling Coil Setpoint
Schedule or Cooling Coil Design Setpoint.
- Warmest – reset the cooling supply air
temperature to the highest supply air temperature that will
meet the cooling requirements of all the zones. The minimum
setpoint allowed is the Cooling Coil Design Setpoint. The
maximum setpoint allowed is defaulted to 18C. (Reference SetpointManager:Warmest)
- OutdoorAirTemperatureReset – reset the cooling
supply air temperature based on the following default rules.
When the outdoor dry-bulb temperature (ODB) is at or below
15.6C the setpoint is 18.0C. When the ODB is at or above 26.7C
the setpoint is the Cooling Coil Design Setpoint. In between,
the setpoint is varied linearly. (Reference SetpointManager:OutdoorAirReset)
The default is None.
Field: Heating
Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the central
heating supply air temperature. The choices are:
- None – no reset, use the Heating Coil Setpoint
Schedule or Heating Coil Design Setpoint.
- OutdoorAirTemperatureReset – reset the heating
supply air temperature based on the following default rules.
When the outdoor dry-bulb temperature (ODB) is at or below
–6.7C the setpoint is the Heating Coil Design Setpoint. When
the ODB is at or above 10.0C the setpoint is 20.0C. In
between, the setpoint is varied linearly. (Reference SetpointManager:OutdoorAirReset).
The default is None.
Field:
Dehumidification Control Type[LINK]
There are two dehumidification control type options
available:
The CoolReheat option cools beyond the dry-bulb
setpoint as required to meet the humidity setpoint if the
system is capable of doing so. Reheat is provided as required
by the terminal unit reheat coils if available.
The default is None which meets the sensible
cooling setpoint only.
Field:
Dehumidification Control Zone Name[LINK]
This field specifies the zone name where the humidistat is
located for controlling dehumidification.
Field:
Dehumidification Setpoint[LINK]
This field specifies the zone humidistat setpoint for
dehumidification in percent (0 to 100). The default is
60%.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric)
object. The default is None.
Field:
Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the
system is operating. If a schedule name is specified, it
defines when the humidifier is available. The schedule values
denote whether the humidifier can run during a given time
period. A schedule value of 1.0 indicates that the humidifier
can be on during a given time period. A value of zero denotes
that the humidifier cannot be used during that time period
Field: Humidifier
Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The
humidifier does not currently autosize, so the default is very
large to allow for adequate capacity. The default is 0.000001
m3/s.
Field:
Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity
moisture output. This field can be autosized. When it is
autosized, it is calculated from the rated capacity in kg/s
and the enthalpy rise in J/kg of the feed water from a
reference temperature of liquid water at 20°C to saturated
steam at 100°C.
Field:
Humidifier Control Zone Name[LINK]
This field specifies the zone name where the humidistat is
located for controlling humidification.
Field: Humidifier
Setpoint[LINK]
This field specifies the zone humidistat setpoint for
humidification in percent (0 to 100). The default is 30%.
Field: Sizing Option[LINK]
This field specifies the sizing method for the system
supply air flow rate. Coincident sizes on the sum of
the coincident zone supply air flow rates.
NonCoincident sizes on sum of the noncoincident zone
design supply air flow rates. The default is
NonCoincident.
As shown in an IDF:
HVACTemplate:System:VAV,
VAV Sys 1, !- Name
FanAvailSched, !- System Availability Schedule Name
autosize, !- Supply Fan Maximum Flow Rate {m3/s}
autosize, !- Supply Fan Minimum Flow Rate {m3/s}
0.7, !- Supply Fan Total Efficiency
600, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
ChilledWater, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule Name
, !- Cooling Coil Setpoint Schedule Name
12.8, !- Cooling Coil Design Setpoint {C}
HotWater, !- Heating Coil Type
, !- Heating Coil Availability Schedule Name
, !- Heating Coil Setpoint Schedule Name
10.0, !- Heating Coil Design Setpoint {C}
0.8, !- Gas Heating Coil Efficiency
0.0, !- Gas Heating Coil Parasitic Electric Load {W}
None, !- Preheat Coil Type
, !- Preheat Coil Availability Schedule Name
, !- Preheat Coil Setpoint Schedule Name
, !- Preheat Coil Design Setpoint {C}
0.8, !- Gas Preheat Coil Efficiency
0.0, !- Gas Preheat Coil Parasitic Electric Load {W}
autosize, !- Maximum Outdoor Air Flow Rate {m3/s}
autosize, !- Minimum Outdoor Air Flow Rate {m3/s}
FixedMinimum, !- Minimum Outdoor Air Control Type
Min OA Sched, !- Minimum Outdoor Air Schedule Name
DifferentialDryBulb, !- Economizer Type
NoLockout, !- Economizer Lockout
19, !- Economizer Upper Temperature Limit {C}
4, !- Economizer Lower Temperature Limit {C}
, !- Economizer Upper Enthalpy Limit {J/kg}
, !- Economizer Maximum Limit Dewpoint Temperature {C}
, !- Supply Plenum Name
PLENUM-1, !- Return Plenum Name
DrawThrough, !- Supply Fan Placement
InletVaneDampers, !- Supply Fan Part-Load Power Coefficients
CycleOnAnyZoneFansOnly, !- Night Cycle Control
, !- Night Cycle Control Zone Name
None, !- Heat Recovery Type
0.70, !- Sensible Heat Recovery Effectiveness
0.65, !- Latent Heat Recovery Effectiveness
None, !- Cooling Coil Setpoint Reset Type
None, !- Heating Coil Setpoint Reset Type
None, !- Dehumidification Control Type
, !- Dehumidification Control Zone Name
60.0, !- Dehumidification Setpoint {percent}
None, !- Humidifier Type
, !- Humidifier Availability Schedule Name
0.000001, !- Humidifier Rated Capacity {m3/s}
2690.0, !- Humidifier Rated Electric Power {W}
, !- Humidifier Control Zone Name
30.0, !- Humidifier Setpoint {percent}
NonCoincident; !- Sizing Option
HVACTemplate:System:PackagedVAV[LINK]
This object simulates the system portion of a packaged
direct-expansion based variable air volume HVAC configuration
with several different heating options. Multiple HVACTemplate:Zone:VAV
objects are usually specified for each HVACTemplate:System:PackagedVAV
object.
Enter a name for the HVACTemplate:System:PackagedVAV
object. This name is used in the HVACTemplate:Zone:VAV
object to reference this system.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be
available for the entire year to perform heating or cooling if
called for by the thermostat. If a schedule name is specified,
those times that the system is available should be specified
as 1.0. Those times that the system is not available should
have a zero value in the schedule specified. Please note that
for this system type, this is a schedule of when the system is
providing air flow.
Field: Supply
Fan Maximum Flow Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to
the sum of the zone air flow rates. If a value is entered here
for the maximum air-flow rate, it is the upper limit on system
flow, even if the zone level air flow inputs sum to a greater
value. This flow rate will not be multiplied by a
sizing factor or by zone multipliers. If using zone
multipliers a value entered here must be large enough to serve
the multiplied zones. The units are m3/s. The
default is Autosize.
Field: Supply
Fan Minimum Flow Rate[LINK]
Enter the minimum supply air volume that may be provided.
This field may be set to autosize. The units are in
m3/s.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the cooling and heating coils. BlowThrough
models a system where the supply air fan is before the cooling
and heating coils. The default is DrawThrough.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1. The
default is 0.7.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered 20oC
at sea level, 101325 Pa. The default is 1000 Pa.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater or equal to the
Supply Fan Total Efficiency and less than or equal to 1. The
default is 0.9.
Field:
Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the
air stream. A value of 0 means that the motor is completely
outside the air stream. A value of 1 means that all of the
motor heat will go into the air stream and act to cause a
temperature rise. Must be between 0 and 1. The default is
1.0.
Field: Cooling Coil
Type[LINK]
The coil types available:
- TwoSpeedDX
- TwoSpeedHumidControlDX
TwoSpeedDX uses the [Coil:Cooling:DX:TwoSpeed](../input-output-reference/page-042.html#coilcoolingdxtwospeed)
object. This is the preferred coil model for most
applications. The TwoSpeedHumidControlDX option uses
the [Coil:Cooling:DX:TwoStageWithHumidityControlMode](../input-output-reference/page-042.html#coilcoolingdxtwostagewithhumiditycontrolmode)
object.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when cooling is only available seasonally. A
schedule value of one indicates that the cooling coil can be
on during a given time period. A value of zero denotes that
the cooling coil cannot be used during that time period.
Field:
Cooling Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the cooling coil is to be
specified, leave this field blank, and the Cooling Coil Design
Setpoint value will be used at all times. If a set point
schedule is to be used for the cooling coil specify the
schedule name here. The schedule should control the supply air
temperature delivered to the zones. For Blow Through fan
placement, this is the leaving air temperature from the
cooling coil. For Draw Through fan placement, this is the
leaving air temperature after the supply fan. The values in
the schedule are in degrees C. This field is ignored if the
Cooling Coil Setpoint Reset Type is something other than None
(see below). The default is None.
Field: Cooling
Coil Design Setpoint[LINK]
Enter the cooling supply air temperature in degrees C to be
used for sizing the cooling coil and zone supply air flow
rates. The default is 12.8C. If no Cooling Coil Setpoint
Schedule or Cooling Coil Setpoint Reset Type is specified,
this value is used as a constant cooling supply air setpoint
temperature.
Field: Cooling Coil
Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm
determine the cooling coil capacity based on the maximum
cooling loads during the cooling design day. If a value is
entered, it represents the full load cooling capacity,
including both sensible and latent capacity, in watts of the
DX coil unit at rated conditions. For Cooling Coil Type =
TwoSpeedDX, the low-speed capacity is assumed to be 0.33 times
this value. For Cooling Coil Type = TwoSpeedHumidControlDX,
the stage 1 capacity is assumed to be 0.5 times this value.
Rated conditions are air entering the cooling coil at the
maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb
with air entering the outdoor condenser coil at 35°C drybulb.
Capacity should be the “gross” capacity where the impact of
supply air fan heat is NOT included. The units are in W. The
default is Autosize.
Field:
Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine
the sensible heat ratio based on the rated capacity and air
flow rate. Otherwise, enter the value of the ratio of the
sensible capacity divided by total cooling capacity of the DX
cooling coil at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
condenser coil at 35°C drybulb. Both the sensible and total
cooling capacities used to define the Rated Sensible Heat
Ratio (SHR) should be “gross” capacity where the impact of
supply air fan heat is NOT included. The default is
Autosize.
Field: Cooling Coil
Rated COP[LINK]
Enter the coefficient of performance defined as the gross
cooling coil capacity in watts divided by electrical power
input in watts of the DX cooling coil unit at rated
conditions. Rated conditions are air entering the cooling coil
at the maximum supply air flow rate at 26.7°C drybulb/19.4°C
wetbulb with air entering the outdoor condenser coil at 35°C
drybulb. The input power includes electric power for the
compressor and condenser fan but does not include the power
consumption of the supply air fan. The default is 3.0.
Field: Heating Coil
Type[LINK]
Enter the type of heating used in the unitary system. The
choices for this field are
Field:
Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be
available anytime the system is operating. If a schedule name
is specified, it defines when the coil is available. This is
most often used when heating is only available seasonally. The
schedule values denote whether the heating coil can run during
a given time period. A schedule value of 1.0 indicates that
the heating coil can be on during a given time period. A value
of zero denotes that the heating coil cannot be used during
that time period
Field:
Heating Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the heating coil is to be
specified, leave this field blank, and the Heating Coil Design
Setpoint value will be used at all times. If a set point
schedule is to be used for the heating coil specify the
schedule name here. The schedule should control the supply air
temperature delivered to the zones. For Blow Through fan
placement, this is the leaving air temperature from the
heating coil. For Draw Through fan placement, this is the
leaving air temperature after the supply fan. The values in
the schedule are in degrees C. This field is ignored if the
Heating Coil Setpoint Reset Type is something other than None
(see below).
Field: Heating
Coil Design Setpoint[LINK]
Enter the heating supply air temperature in degrees C to be
used for sizing the heating coil and zone supply air flow
rates. If no Heating Coil Setpoint Schedule or Heating Coil
Setpoint Reset Type is specified, this value is used as a
constant heating supply air setpoint temperature. The default
is 10.0C.
Field: Heating Coil
Capacity[LINK]
Enter Autosize to allow the sizing algorithm to determine
the proper capacity required based on the loads experienced
during the heating design day. If a value is specified, it is
the maximum amount of heat that the coil can deliver in
Watts.
Field: Gas
Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent.
A burner that is 80% efficient would have an entry of 0.8
here, which is the default
Field:
Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
heating coil operation, such as a combustion fan. The units
are in W. The default is 0.0 W.
Field: Maximum
Outdoor Air Flow Rate[LINK]
Enter Autosize or a value for the maximum amount of outdoor
air flow into the unit when the economizer is operating.
Autosize means that 100% of the full supply flow may be taken
from outdoor air. If a value is entered, it is used instead of
the autosize value. The units are in m3/s. That is, the
entered value is used to define the Maximum Outdoor Air Flow
Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template. The default is
Autosize.
Field: Minimum
Outdoor Air Flow Rate[LINK]
Enter Autosize or the value for the minimum amount of
outdoor air that can enter the unit and be distributed to the
zones. Usually this is set to autosize and the value is
calculated by the outdoor air requirements of each zone. If a
value is entered it overrides the outdoor air specification
from the zone level. The units are in m3/s. The default is
Autosize. Note if heat recovery is specified (see Heat
Recovery Type below), then a value must be entered in this
field, because heat recovery equipment is not yet autosizable.
That is, the entered value is used to define the Minimum
Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair)
object that will be generated by this template.
Field:
Minimum Outdoor Air Control Type[LINK]
Choices for this field are FixedMinimum or
ProportionalMinimum. FixedMinimum means that
the minimum outdoor air flow rate is fixed no matter what the
actual system flow rate is. ProportionalMinimum means the
minimum outdoor air flow rate varies in proportion to the
total system air flow rate. The default is
ProportionalMinimum.
Field:
Minimum Outdoor Air Schedule Name[LINK]
Leave this field blank if you want the minimum outdoor air
to be the same for all hours in the entire year. If a schedule
name is specified, values are decimal fractions (0.0 – 1.0)
that multiply the minimum outdoor air flow rate. This schedule
is useful for reducing the outdoor air flow rate to zero
during unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
- ‘FixedDryBulb’
- ‘DifferentialDryBulb’
- ‘FixedEnthalpy’
- ‘DifferentialEnthalpy’
- ‘ElectronicEnthalpy’ (i.e., humidity ratio curve
strategy)
- ‘FixedDewPointAndDryBulb’
- ‘DifferentialDryBulbAndEnthalpy’
- ‘NoEconomizer’
Choosing NoEconomizer means the economizer
will not operate and the outdoor airflow rate will be at the
minimum for the entire simulation.
Choosing FixedDryBulb means the economizer
will set the outdoor airflow rate at minimum if the outdoor
air temperature is higher than a specified dry-bulb
temperature limit.
Choosing DifferentialDryBulb will trigger
the outdoor airflow to minimum when the dry-bulb temperature
of outdoor air is higher than the dry-bulb temperature of the
return air.
FixedEnthalpy checks the upper limit of
the enthalpy given as a field input against the enthalpy
content of outdoor air and will set the outdoor airflow rate
to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing
but compares the return air enthalpy with the enthalpy of
outdoor air. When the enthalpy of outdoor air is greater than
the enthalpy of the return air, the outdoor air flow rate is
set to minimum.
Choosing ElectronicEnthalpy enables the
simulation to calculate the humidity ratio limit of outdoor
air based on the dry-bulb temperature of outdoor air and a
quadratic/cubic curve, and compare it to the actual outdoor
air humidity ratio. If the actual outdoor humidity ratio is
greater than the calculated humidity ratio limit, then the
outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares
both the outdoor dewpoint temperature and the outdoor dry-bulb
temperature to their specified high limit values. If either
outdoor temperature exceeds the high limit value, the outdoor
airflow rate is set to minimum.
Another option
DifferentialDryBulbAndEnthalpy enables the
control strategy to be based on both the
DifferentialDryBulb and
DifferentialEnthalpy economizer control
strategies.
In addition to all economizer control types listed above,
each control type checks for user-entered values for the upper
limit of dry-bulb temperature, enthalpy limit, humidity ratio
limit and dewpoint limit. The outdoor air flow rate is set to
minimum if any of these entered limits are exceeded.
The default for this field is
NoEconomizer.
Field: Economizer
Lockout[LINK]
Enter one of the following choices for this field:
- NoLockout
- LockoutWithHeating
- LockoutWithCompressor
The default value is NoLockout. The
LockoutWithHeating means that if the packaged
unit is in heating mode, the economizer is locked out – i.e.,
the economizer dampers are closed and there is minimum outdoor
air flow. LockoutWithCompressor means that in
addition to locking out the economizer when the unit is in
heating mode the economizer is locked out when the DX unit
compressor is on. In other words, when the DX coil is off, the
economizer must meet the entire cooling load – it isn’t
allowed to operate in conjunction with the DX cooling coil.
Similarly, when the DX coil is operating, the economizer is
not allowed to operate. The
LockoutWithCompressor option is sometimes
called a “nonintegrated” economizer.
Field:
Economizer Maximum Limit Dry-Bulb Temperature[LINK]
Input for this field is the outdoor air temperature high
limit (ºC) for economizer operation. If the outdoor air
temperature is above this limit, the outdoor airflow rate will
be set to the minimum. This field is required if Economizer
Control Type ‘FixedDryBulb’ or ‘FixedDewPointAndDryBulb’ has
been specified. No input (blank) in this field means that
there is no outdoor air temperature high limit control.
Field:
Economizer Maximum Limit Enthalpy[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for
economizer operation. If the outdoor air enthalpy is above
this value, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
enthalpy limit control.
Field:
Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC)
for economizer operation. If the outdoor air dewpoint
temperature is above this value, the outdoor airflow rate will
be set to the minimum. This field is required if the
Economizer Control Type ‘FixedDewPointAndDryBulb’ has been
specified. No input (blank) in this field means that there is
no outdoor air dewpoint limit control.
Field:
Economizer Minimum Limit Dry-Bulb Temperature[LINK]
Enter the outdoor air temperature low limit (C) for
economizer operation. If the outdoor air temperature is below
this limit, the outdoor air flow rate will be set to the
minimum and heat recovery will be enabled if available. No
input or zero in this field means that there is no outdoor air
temperature low limit control.
Field: Supply Plenum
Name[LINK]
Set to blank if no supply plenum is to be modeled. If a
supply plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This supply plenum serves all zones on this system. If
any zone supply plenums have been specified, the outlet from
the system supply plenum will flow through the zone supply
plenum to the zone terminal unit.
Field: Return Plenum
Name[LINK]
Set to blank if no return plenum is to be modeled. If a
return plenum is modeled, it must be modeled as a zone with
surfaces, and the name of the plenum zone should be entered
here. This return plenum serves all zones on this system. If
any zone return plenums have been specified, the return air
from the zone will flow through the zone return plenum and
then into the system return plenum.
Field:
Supply Fan Part-Load Power Coefficients[LINK]
Select the set of generic pre-defined coefficients to use
for the supply fan part-load power consumption. This alpha
field has the following choices:
- InletVaneDampers
- OutletDampers
- VariableSpeedMotor
- ASHRAE90.1-2004Appendix G
- VariableSpeedMotorPressureReset
The default is InletVaneDampers. The resulting
power curves are shown in Figure 147 below. The ASHRAE
90.1-2004 Appendix G coefficients are from TABLE G3.1.3.15,
Method 2. The other sets of coefficients are from the
EnergyPlus Input Output Reference, Fan Coefficient Values
table. The VariableSpeedMotorPressureReset option is
based on Good Static Pressure Reset VSD Fan from Energy Design
Resources’: Design Guidelines: Advanced Variable Air
Volume (VAV) Systems (EDR_DesignGuidelines_VAV.pdf).
Field: Night Cycle
Control[LINK]
Enter the system behavior during times when the System
Availability Schedule is zero (off). The possible inputs are
StayOff, CycleOnAny, CycleOnControl
Zone](page-011.html#zone) or CycleOnAnyZoneFansOnly.
StayOff means the system will remain off, no matter
how hot or cold the zones may be. CycleOnAny means
that if any zone served by this system has an air temperature
outside the cooling or heating set points the central fan will
turn on even though the System Availability Schedule indicates
the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone)
means the same thing except the availability manager looks at
the temperature in only the zone specified in Night Cycle
Control [Zone](../input-output-reference/page-011.html#zone)
Name. CycleOnAnyZoneFansOnly is the same as
CycleOnAny except that only the zone fans are cycled
on and the central air handler fan is left off (applicable
only if using [HVACTemplate:Zone:VAV:FanPowered in one or more
zones). The default is StayOff.
Field: Night
Cycle Control Zone Name[LINK]
For the Night Cycle Control option Cycle On Control Zone
enter the name of the control zone. For other Night Cycle
Control options, this field is ignored.
Field: Heat Recovery
Type[LINK]
Enter the type of air-to-air heat recovery which is
available between the relief air stream and the outdoor air
inlet stream. The choices are:
The default is None. If heat
recovery is specified (i.e., Sensible or
Enthalpy), then a value must be entered in
the Minimum Outdoor Air Flow Rate field, because heat recovery
equipment is not yet autosizable. The entered Minimum Outdoor
Air Flow Rate is used to define the Nominal Supply Air Flow
Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent)
object generated by this template.
Field:
Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is
applied as a constant effectiveness at all conditions. The
valid range is from 0.0 to 1.0, and the default is 0.70.
Field:
Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat
Recovery Type is Enthalpy. This is applied as a
constant effectiveness at all conditions. The valid range is
from 0.0 to 1.0, and the default is 0.65.
Field:
Cooling Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the cooling
supply air temperature. The choices are:
- None – no reset, use the Cooling Coil Setpoint
Schedule or Cooling Coil Design Setpoint.
- Warmest – reset the cooling supply air
temperature to the highest supply air temperature that will
meet the cooling requirements of all the zones. The minimum
setpoint allowed is the Cooling Coil Design Setpoint. The
maximum setpoint allowed is defaulted to 18C. (Reference SetpointManager:Warmest)
- OutdoorAirTemperatureReset – reset the cooling
supply air temperature based on the following default rules.
When the outdoor dry-bulb temperature (ODB) is at or below
15.6C the setpoint is 18.0C. When the ODB is at or above 26.7C
the setpoint is the Cooling Coil Design Setpoint. In between,
the setpoint is varied linearly. (Reference SetpointManager:OutdoorAirReset)
The default is None.
Field:
Heating Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the central
heating supply air temperature. The choices are:
- None – no reset, use the Heating Coil Setpoint
Schedule or Heating Coil Design Setpoint.
- OutdoorAirTemperatureReset – reset the heating
supply air temperature based on the following default rules.
When the outdoor dry-bulb temperature (ODB) is at or below
–6.7C the setpoint is the Heating Coil Design Setpoint. When
the ODB is at or above 10.0C the setpoint is 20.0C. In
between, the setpoint is varied linearly. (Reference SetpointManager:OutdoorAirReset).
The default is None.
Field:
Dehumidification Control Type[LINK]
There are two dehumidification control type options
available:
The CoolReheat option cools beyond the dry-bulb
setpoint as required to meet the humidity setpoint if the
system is capable of doing so. Reheat is provided as required
by the terminal unit reheat coils if available.
The default is None which meets the sensible
cooling setpoint only.
Field:
Dehumidification Control Zone Name[LINK]
This field specifies the zone name where the humidistat is
located for controlling dehumidification.
Field:
Dehumidification Setpoint[LINK]
This field specifies the zone humidistat setpoint for
dehumidification in percent (0 to 100). The default is
60%.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric)
object. The default is None.
Field:
Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the
system is operating. If a schedule name is specified, it
defines when the humidifier is available. The schedule values
denote whether the humidifier can run during a given time
period. A schedule value of 1.0 indicates that the humidifier
can be on during a given time period. A value of zero denotes
that the humidifier cannot be used during that time period
Field: Humidifier
Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The
humidifier does not currently autosize, so the default is very
large to allow for adequate capacity. The default is 0.000001
m3/s.
Field:
Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity
moisture output. This field can be autosized. When it is
autosized, it is calculated from the rated capacity in kg/s
and the enthalpy rise in J/kg of the feed water from a
reference temperature of liquid water at 20°C to saturated
steam at 100°C.
Field:
Humidifier Control Zone Name[LINK]
This field specifies the zone name where the humidistat is
located for controlling humidification.
Field: Humidifier
Setpoint[LINK]
This field specifies the zone humidistat setpoint for
humidification in percent (0 to 100). The default is 30%.
Field: Sizing Option[LINK]
This field specifies the sizing method for the system
supply air flow rate. Coincident sizes on the sum of
the coincident zone supply air flow rates.
NonCoincident sizes on sum of the noncoincident zone
design supply air flow rates. The default is
NonCoincident.
As shown in an IDF:
HVACTemplate:System:PackagedVAV,
DXVAV Sys 1, !- Name
FanAvailSched, !- System Availability Schedule Name
autosize, !- Supply Fan Maximum Flow Rate {m3/s}
autosize, !- Supply Fan Minimum Flow Rate {m3/s}
DrawThrough, !- Supply Fan Placement
0.7, !- Supply Fan Total Efficiency
1000, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
TwoSpeedDX, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule Name
, !- Cooling Coil Setpoint Schedule Name
12.8, !- Cooling Coil Design Setpoint {C}
autosize, !- Cooling Coil Capacity {W}
autosize, !- Cooling Coil Rated Sensible Heat Ratio
3, !- Cooling Coil Rated COP
Gas, !- Heating Coil Type
, !- Heating Coil Availability Schedule Name
, !- Heating Coil Setpoint Schedule Name
10, !- Heating Coil Design Setpoint {C}
autosize, !- Heating Coil Capacity {W}
0.8, !- Gas Heating Coil Efficiency
, !- Gas Heating Coil Parasitic Electric Load {W}
autosize, !- Maximum Outdoor Air Flow Rate {m3/s}
autosize, !- Minimum Outdoor Air Flow Rate {m3/s}
ProportionalMinimum, !- Minimum Outdoor Air Control Type
Min OA Sched, !- Minimum Outdoor Air Schedule Name
DifferentialDryBulb, !- Economizer Type
NoLockout, !- Economizer Lockout
19, !- Economizer Maximum Limit Dry-Bulb Temperature {C}
, !- Economizer Maximum Limit Enthalpy {J/kg}
, !- Economizer Maximum Limit Dewpoint Temperature {C}
4, !- Economizer Minimum Limit Dry-Bulb Temperature {C}
, !- Supply Plenum Name
PLENUM-1, !- Return Plenum Name
InletVaneDampers, !- Supply Fan Part-Load Power Coefficients
CycleOnAny, !- Night Cycle Control
, !- Night Cycle Control Zone Name
None, !- Heat Recovery Type
0.7, !- Sensible Heat Recovery Effectiveness
0.65, !- Latent Heat Recovery Effectiveness
None, !- Cooling Coil Setpoint Reset Type
None, !- Heating Coil Setpoint Reset Type
None, !- Dehumidification Control Type
, !- Dehumidification Control Zone Name
60, !- Dehumidification Setpoint {percent}
None, !- Humidifier Type
, !- Humidifier Availability Schedule Name
0.000001, !- Humidifier Rated Capacity {m3/s}
2690, !- Humidifier Rated Electric Power {W}
, !- Humidifier Control Zone Name
30, !- Humidifier Setpoint {percent}
NonCoincident; !- Sizing Option
HVACTemplate:System:DedicatedOutdoorAir[LINK]
The HVACTemplate:System:DedicatedOutdoorAir
creates a dedicated outdoor air system which must be used in
conjunction with one or more of the following objects:
HVACTemplate:Zone:FanCoil
HVACTemplate:Zone:PTAC
HVACTemplate:Zone:PTHP
HVACTemplate:Zone:WaterToAirHeatPump
It is a constant volume dedicated outdoor air system which
can serve multiple zones. It may have any combination of
heating coil, cooling coil, and heat recovery. It may have
dehumidification and humidification controls as well as
several supply temperature control types. It supplies 100%
outdoor air when the system is available, and assumes an equal
volume of return air is available for heat recovery. If the
system to be modeled does not have actual return ducts, but
collects flow from exhaust fans to a central heat recovery
point, then this approach should be equivalent. If the system
does not have heat recovery and the air is exhausted or leaves
by exfiltration, then the return path of this system will
simply be a path to dump the flow as relief air with no impact
on energy use.
There may be more than one HVACTemplate:System:DedicatedOutdoorAir
object in an idf file. If a zone is to be served by one of
these systems, this is specified in the HVACTemplate:Zone:*
object using the field “Dedicated Outdoor Air System Name”.
For zones which are served by one of these DOAS systems, the
outdoor air flow rate in the zone equipment (fan coil, PTAC,
etc.) will be set to zero.
This field is a unique name which the user assigns to this
system. This name can then be referred to in an
HVACTemplate:Zone:* object to specify that this system
provides outdoor air to that zone.
Field:
System Availability Schedule Name[LINK]
Leave this field blank if you want the system to operate at
all times. If a schedule name is specified, those times that
the system is operating should be specified as 1.0. Those
times that the system is not operating should have a zero
value in the schedule specified. Please note that for this
system type, this is a schedule of when the system is
providing air flow.
Field: Air Outlet Type[LINK]
This field indicates if the air is delivered directly into
the zone(s) or into the other system(s) that serve the zone(s)
(e.g. fan coil system). For now, only one option is available
for this field: DirectIntoZone.
Field: Supply Fan Flow
Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to
the sum of the zone air flow rates. If a value is entered here
for the maximum air-flow rate, it is the upper limit on system
flow, even if the zone air flow inputs sum to a greater value.
The units are m3/s.
Field: Supply Fan
Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the
ratio of the power delivered to the air to the electrical
input power at maximum flow. This is also the product of the
fan motor efficiency and fan (impeller) efficiency. The motor
efficiency is the power delivered to the shaft divided by the
electrical power input to the motor. The fan efficiency is the
power delivered to the air divided by the shaft power. The
power delivered to the fluid is the mass flow rate of the air
multiplied by the pressure rise divided by the air density.
Must be greater than 0 and less than or equal to 1.
Field: Supply Fan
Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard
conditions. Standard conditions are considered to be
20oC at sea level, 101325 Pa.
Field: Supply Fan
Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the
electrical power consumed. Must be greater than 0 and less
than or equal to 1.
Field:
Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the
air stream. A value of 0 means that the motor is completely
outside the air stream. A value of 1 means that all of the
motor heat will go into the air stream and act to cause a
temperature rise. Must be between 0 and 1.
Field: Supply Fan
Placement[LINK]
Enter the supply fan placement type. This alpha field has
two choices, DrawThrough or BlowThrough.
DrawThrough models a system where the supply air fan
is after the cooling and heating coils. BlowThrough
models a system where the supply air fan is before the cooling
and heating coils. The default is DrawThrough.
Field: Cooling Coil
Type[LINK]
There are seven coil types available:
- ChilledWater
- ChilledWaterDetailedFlatModel
- TwoSpeedDX
- TwoStageDX
- TwoStageHumidityControlDX
- HeatExchangerAssistedChilledWater
- HeatExchangerAssistedDX
- None
ChilledWater uses the [Coil:Cooling:Water](../input-output-reference/page-042.html#coilcoolingwater)
object with the DetailedAnalysis option. This is the preferred
coil model for most chilled water applications.
ChilledWaterDetailedFlatModel uses the [Coil:Cooling:Water:DetailedGeometry](../input-output-reference/page-042.html#coilcoolingwaterdetailedgeometry)
object. This option is available for special applications.
TwoSpeedDX uses the [Coil:Cooling:DX:TwoSpeed](../input-output-reference/page-042.html#coilcoolingdxtwospeed)
object.
TwoStageDX and TwoStageHumidityControlDX
use the [Coil:Cooling:DX:TwoStageWithHumidityControlMode](../input-output-reference/page-042.html#coilcoolingdxtwostagewithhumiditycontrolmode)
object.
HeatExchangerAssistedChilledWater uses the [CoilSystem:Cooling:Water:HeatExchangerAssisted](../input-output-reference/page-042.html#coilsystemcoolingwaterheatexchangerassisted),
[HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent),
and [Coil:Cooling:Water](../input-output-reference/page-042.html#coilcoolingwater)
objects.
HeatExchangerAssistedDX uses the [CoilSystem:Cooling:DX:HeatExchangerAssisted](../input-output-reference/page-042.html#coilsystemcoolingdxheatexchangerassisted),
[HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent),
and [Coil:Cooling:DX:SingleSpeed](../input-output-reference/page-042.html#coilcoolingdxsinglespeed)
objects.
The default type is ChilledWater.
Field:
Cooling Coil Availability Schedule Name[LINK]
Usually left blank, which allows the cooling coil to be
available as needed anytime the system is operating. If a
schedule name is specified, it defines when the cooling coil
is available. This is most often used when cooling is only
available seasonally. A schedule value of one indicates that
the cooling coil can be on during a given time period. A value
of zero denotes that the cooling coil cannot be used during
that time period.
Field:
Cooling Coil Setpoint Control Type[LINK]
Specifies the cooling coil setpoint control type:
- FixedSetpoint
- Scheduled
- OutdoorAirTemperatureReset
FixedSetpoint uses the Cooling Coil Design Setpoint as the
supply air setpoint. Scheduled uses the Cooling Coil Setpoint
Schedule to set the supply air setpoint.
OutdoorAirTemperatureReset varies the supply air setpoint
based on the values entered for Cooling Coil Setpoint at
Outdoor Dry-Bulb Low, Cooling Coil Reset Outdoor Dry-Bulb Low,
Cooling Coil Setpoint at Outdoor Dry-Bulb High, and Cooling
Coil Reset Outdoor Dry-Bulb High. The default is
FixedSetpoint.
NOTE: The user must ensure that the cooling coil and
heating coil setpoints do not overlap to avoid unwanted
simultaneous heating and cooling. The simulation will not
check this automatically. It is recommended that the cooling
setpoint always be at least 0.1C higher than the heating coil
setpoint.
Field: Cooling
Coil Design Setpoint[LINK]
Enter the cooling supply air temperature in C to be used
for sizing the cooling coil and zone supply air flow rates.
The default is 12.8C. If Cooling Coil Setpoint Control Type =
FixedSetpoint, then this value is also used as the constant
cooling supply air setpoint temperature.
Field:
Cooling Coil Setpoint Schedule Name[LINK]
This field is used when Cooling Coil Setpoint Control Type
= Scheduled. The schedule should control the supply air
temperature delivered to the zones. For Blow Through fan
placement, this is the leaving air temperature from the
cooling coil. For Draw Through fan placement, this is the
leaving air temperature after the supply fan. The values in
the schedule are in degrees C. This field is ignored if the
Cooling Coil Setpoint Reset Type is something other than
Scheduled (see above).
Field:
Cooling Coil Setpoint at Outdoor Dry-Bulb Low[LINK]
The cooling coil supply air setpoint temperature in C when
the outdoor dry-bulb temperature is at or below the low limit
(Cooling Coil Reset Outdoor Dry-Bulb Low). Used only when
Cooling Coil Setpoint Control Type =
OutdoorAirTemperatureReset. The default is 15.6C.
Field:
Cooling Coil Reset Outdoor Dry-Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
below this temperature, the setpoint is the value of Cooling
Coil Setpoint at Outdoor Dry-Bulb Low. Used only when Cooling
Coil Setpoint Control Type = OutdoorAirTemperatureReset. The
default is 15.6C.
Field:
Cooling Coil Setpoint at Outdoor Dry-Bulb High[LINK]
The cooling coil supply air setpoint temperature in C when
the outdoor dry-bulb temperature is at or above the high limit
(Cooling Coil Reset Outdoor Dry-Bulb High). Used only when
Cooling Coil Setpoint Control Type =
OutdoorAirTemperatureReset. The default is 12.8C.
Field:
Cooling Coil Reset Outdoor Dry-Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
above this temperature, the setpoint is the value of Cooling
Coil Setpoint at Outdoor Dry-Bulb High. Used only when Cooling
Coil Setpoint Control Type = OutdoorAirTemperatureReset. The
default is 23.3C.
Field: DX Cooling Coil
Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm
determine the cooling coil capacity based on the maximum
cooling loads during the cooling design day. If a value is
entered, it represents the full load cooling capacity,
including both sensible and latent capacity, in watts of the
DX coil unit at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
air-cooled condenser coil at 35°C drybulb. Capacity should be
the “gross” capacity where the impact of supply air fan heat
is NOT included. The units are in W. The default is Autosize.
This field is only used when the cooling coil type is set to
one of the DX options. For two-speed DX coils, the low-speed
capacity is assumed to be 0.33 times this value. For two-stage
DX coils, the stage 1 capacity is assumed to be 0.5 times this
value.
Field: DX
Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine
the sensible heat ratio based on the rated capacity and air
flow rate. Otherwise, enter the value of the ratio of the
sensible capacity divided by total cooling capacity of the DX
cooling coil at rated conditions. Rated conditions are air
entering the cooling coil at the maximum supply air flow rate
at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor
air-cooled condenser coil at 35°C drybulb. Both the sensible
and total cooling capacities used to define the Rated Sensible
Heat Ratio (SHR) should be “gross” capacity where the impact
of supply air fan heat is NOT included. The default is
Autosize. This field is only used when the cooling coil type
is set to one of the DX options. For two-speed DX coils, the
low-speed SHR is assumed to be equal to this value. For
two-stage DX coils, the stage 1 SHR is assumed to be equal to
this value. For two-stage DX coil with humidity control, the
humidity control mode SHR is assumed to be 0.9 times this
value (for both stage 1 and stage 2).
Field: DX Cooling
Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross
cooling coil capacity in watts divided by electrical power
input in watts of the DX cooling coil unit at rated
conditions. Rated conditions are air entering the cooling coil
at the maximum supply air flow rate at 26.7°C drybulb/19.4°C
wetbulb with air entering the outdoor air-cooled condenser
coil at 35°C drybulb. The input power includes electric power
for the compressor and condenser fan but does not include the
power consumption of the supply air fan. The default is 3.0.
This field is only used when the cooling coil type is set to
one of the DX options. For two-speed DX coils, the low-speed
COP is assumed to be 1.5 times this value. For two-stage DX
coils, the stage 1 COP is assumed to be this this value. For
two-stage DX coil with humidity control, the humidity control
mode COP is assumed to be 0.9 times this value (for both stage
1 and stage 2).
Field: Heating Coil
Type[LINK]
The heating coil is located in the supply air stream,
downstream of the cooling coil. If no central heating coil is
used in the dedicated outdoor air system, then the option
“none” should be specified here. Otherwise this indicates the
type of heating coil. The choices for this field are
- HotWater
- Electric
- Gas
- None
The default value is HotWater. If a heating coil is
specified, the heating and cooling coil setpoint controls and
availability schedules must coordinate to prevent the coils
from opposing each other. When the dehumidification control
type is set to CoolReheatHeatingCoil, the heating
coil is used for reheat.
Field:
Heating Coil Availability Schedule Name[LINK]
Usually left blank, which allows the heating coil to be
available as needed anytime the system is operating. If a
schedule name is specified, it defines when the heating coil
is available. This is most often used when heating is only
available seasonally. The schedule values denote whether the
heating coil can run during a given time period. A schedule
value of one indicates that the heating coil can be on during
a given time period. A value of zero denotes that the heating
coil cannot be used during that time period.
Field:
Heating Coil Setpoint Control Type[LINK]
Specifies the cooling coil setpoint control type:
- FixedSetpoint
- Scheduled
- OutdoorAirTemperatureReset
FixedSetpoint uses the Heating Coil Design Setpoint as the
supply air setpoint. Scheduled uses the Heating Coil Setpoint
Schedule to set the supply air setpoint.
OutdoorAirTemperatureReset varies the supply air setpoint
based on the values entered for Heating Coil Setpoint at
Outdoor Dry-Bulb Low, Heating Coil Reset Outdoor Dry-Bulb Low,
Heating Coil Setpoint at Outdoor Dry-Bulb High, and Heating
Coil Reset Outdoor Dry-Bulb High. The default is
FixedSetpoint.
NOTE: The user must ensure that the cooling coil and
heating coil setpoints do not overlap to avoid unwanted
simultaneous heating and cooling. The simulation will not
check this automatically. It is recommended that the cooling
setpoint always be at least 0.1C higher than the heating coil
setpoint.
Field: Heating
Coil Design Setpoint[LINK]
Enter the heating supply air temperature in C to be used
for sizing the heating coil and zone supply air flow rates. If
Heating Coil Setpoint Control Type = FixedSetpoint, then this
value is also used as the constant heating supply air setpoint
temperature. The default is 12.2C.
Field:
Heating Coil Setpoint Schedule Name[LINK]
This field is used when Heating Coil Setpoint Control Type
= Scheduled. The schedule should control the supply air
temperature delivered to the zones. For Blow Through fan
placement, this is the leaving air temperature from the
heating coil. For Draw Through fan placement, this is the
leaving air temperature after the supply fan. The values in
the schedule are in degrees C.
Field:
Heating Coil Setpoint at Outdoor Dry-Bulb Low[LINK]
The heating coil supply air setpoint temperature in C when
the outdoor dry-bulb temperature is at or below the low limit
(Heating Coil Reset Outdoor Dry-Bulb Low). Used only when
Heating Coil Setpoint Control Type =
OutdoorAirTemperatureReset. The default is 15.0C.
Field:
Heating Coil Reset Outdoor Dry-Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
below this temperature, the setpoint is the value of Heating
Coil Setpoint at Outdoor Dry-Bulb Low. Used only when Heating
Coil Setpoint Control Type = OutdoorAirTemperatureReset. The
default is 7.8C.
Field:
Heating Coil Setpoint at Outdoor Dry-Bulb High[LINK]
The heating coil supply air setpoint temperature in C when
the outdoor dry-bulb temperature is at or above the high limit
(Heating Coil Reset Outdoor Dry-Bulb High). Used only when
Heating Coil Setpoint Control Type =
OutdoorAirTemperatureReset. The default is 12.2C.
Field:
Heating Coil Reset Outdoor Dry-Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
above this temperature, the setpoint is the value of Heating
Coil Setpoint at Outdoor Dry-Bulb High. Used only when Heating
Coil Setpoint Control Type = OutdoorAirTemperatureReset. The
default is 12.2C.
Field: Gas
Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent.
A burner that is 80% efficient would have an entry of 0.8
here, which is the default. This field is only used when the
heating coil type is set to gas.
Field:
Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas
heating coil operation, such as a combustion fan. The units
are in W. This field is only used when the heating coil type
is set to gas.
Field: Heat Recovery
Type[LINK]
Enter the type of air-to-air heat recovery which is
available between the relief air stream and the outdoor air
inlet stream. The choices are:
The default is None.
Field:
Heat Recovery Sensible Effectiveness [][LINK]
Enter the sensible heat recovery effectiveness. This is
applied as a constant effectiveness at all conditions. The
valid range is from 0.0 to 1.0, and the default is 0.70.
Field: Heat
Recovery Latent Effectiveness [][LINK]
Enter the latent heat recovery effectiveness if Heat
Recovery Type is Enthalpy. This is applied as a
constant effectiveness at all conditions. The valid range is
from 0.0 to 1.0, and the default is 0.65.
Field: Heat
Recovery Heat Exchanger Type[LINK]
This alpha field denotes the type of heat exchanger being
modeled: Plate (e.g., fixed plate) or Rotary (e.g., rotating
cylinder or wheel). The default choice for this field is
“Plate”. The heat exchanger type affects the modeling of frost
control options and supply air outlet temperature control. For
rotary heat exchangers, rotational speed is varied to control
frost formation or the supply air outlet temperature. For
plate exchangers, air bypass around the heat exchanger is used
to obtain the desired effect.
Field: Heat
Recovery Frost Control Type[LINK]
This alpha field has four choices: None,
ExhaustAirRecirculation, ExhaustOnly and
MinimumExhaustTemperature. If this field is left blank, the
default frost control type is “None”. For modeling preheat
frost control, specify “None” for this input field and insert
a separate heating coil object in the supply inlet air stream
to keep the air temperature above the desired frost threshold
temperature.
ExhaustAirRecirculation: dampers are used to
direct exhaust air back into the zone through the supply side
of the heat exchanger when the supply (outdoor) air inlet
temperature falls below a threshold temperature. The fraction
of time that exhaust air is circulated through the supply side
of the heat exchanger is dependent on the supply (outdoor) air
inlet temperature with respect to the threshold temperature,
the initial defrost time fraction, and the rate of change of
defrost time. When exhaust air is being recirculated, no
supply (outdoor ventilation) air is being provided through the
heat exchanger unit (which may or may not be acceptable
regarding ventilation for occupants).
ExhaustOnly (supply air bypass): this control
cycles off the supply air flow through the heat exchanger for
a certain period of time while the exhaust air continues to
flow through the exhaust side of the heat exchanger. The
fraction of time that the supply flow through the heat
exchanger is cycled off is dependent on the supply (outdoor)
air inlet temperature with respect to the threshold
temperature, the initial defrost time fraction, and the rate
of change of defrost time. When implemented in real
applications, provisions are usually made to avoid building
depressurization when this frost control is operating
(automatic or pressure-operated dampers, or a bypass air
damper around the supply side of the heat exchanger). For this
frost control type, it is assumed that the supply air is
bypassed around the heat exchanger during frost control
operation (i.e., the total supply flow is not reduced during
defrost, but merely bypassed around the heat exchanger).
MinimumExhaustTemperature: the temperature of the
exhaust air leaving the heat exchanger is monitored and the
heat exchanger effectiveness is decreased (by slowing heat
exchanger rotation or bypassing supply air around the plate
exchanger) to keep the exhaust air from falling below the
threshold temperature.
Field:
Dehumidification Control Type[LINK]
There are three dehumidification control type options
available:
- None
- CoolReheatHeatingCoil
- CoolReheatDesuperheater
- Multimode
The CoolReheatHeatingCoil option cools beyond the
dry-bulb setpoint as required to meet the humidity setpoint if
the system is capable of doing so. Reheat is provided as
required by the heating coil, if available.
The CollReheatDesuperheater option cools beyond
the dry-bulb setpoint as required to meet the humidity
setpoint if the system is capable of doing so. Reheat is
provided by a desuperheater coil (Ref. object [Coil:Heating:Desuperheater](../input-output-reference/page-042.html#coilheatingdesuperheater)).
The desuperheater coil setpoint is set to the cooling setpoint
and the desuperheater Heat Reclaim Recovery Efficiency is set
to 0.3. CollReheatDesuperheater is only applicable
for Cooling Coil Type TwoSpeedDX, TwoStageDX,
TwoStageHumidityControlDX, or
HeatExchangerAssistedDX.
Multimode is only applicable for cooling coil type
TwoStageHumidityControlDX. In this case, the enhanced
dehumidification mode is activated as needed, but the system
operates to meet the sensible dry-bulb temperature cooling
setpoint.
The default is None which meets the sensible
dry-bulb temperature cooling setpoint only.
Field:
Dehumidification Setpoint[LINK]
This field specifies the supply air humidity ratio setpoint
for dehumidification. The default is 0.00924 kgWater/kgDryAir
(12.8C or 55F dewpoint). This value is also used as the
Central Cooling Design Supply Air Humidity Ratio in the [Sizing:System](../input-output-reference/page-019.html#sizingsystem)
object. If a Dehumidification Setpoint Schedule Name is
specified, the schedule will be used for control.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric)
object. The default is None.
Field:
Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the
system is operating. If a schedule name is specified, it
defines when the humidifier is available. The schedule values
denote whether the humidifier can run during a given time
period. A schedule value of 1.0 indicates that the humidifier
can be on during a given time period. A value of zero denotes
that the humidifier cannot be used during that time
period.
Field: Humidifier
Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The
humidifier does not currently autosize, so the default is very
large to allow for adequate capacity. The default is 0.000001
m3/s.
Field:
Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity
moisture output. This field can be autosized. When it is
autosized, it is calculated from the rated capacity in kg/s
and the enthalpy rise in J/kg of the feed water from a
reference temperature of liquid water at 20°C to saturated
steam at 100°C.
Field: Humidifier
Setpoint[LINK]
This field specifies the supply air humidity ratio setpoint
for humidification. The default is 0.003 kgWater/kgDryAir.
This value is also used as the Central Heating Design Supply
Air Humidity Ratio in the [Sizing:System](../input-output-reference/page-019.html#sizingsystem)
object. If a Humidifier Setpoint Schedule Name is specified,
the schedule will be used for control.
Field:
Dehumidification Setpoint Schedule Name[LINK]
Enter the name of the dehumidification setpoint schedule.
If this field is left blank, the setpoint will be constant at
the Dehumidification Setpoint, The values in the schedule are
in units of humidity ratio (kgWater/kgDryAir or
lbWater/lbDryAir).
Field:
Humidifier Setpoint Schedule Name[LINK]
Enter the name of the humidifier setpoint schedule. If this
field is left blank, the setpoint will be constant at the
Humidifier Setpoint, The values in the schedule are in units
of humidity ratio (kgWater/kgDryAir or lbWater/lbDryAir).
As shown in an IDF:
HVACTemplate:System:DedicatedOutdoorAir,
DOAS, !- Name
, !- System Availability Schedule Name
DirectIntoZone, !- Air Outlet Type
autosize, !- Supply Fan Flow Rate {m3/s}
0.7, !- Supply Fan Total Efficiency
1000, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
DrawThrough, !- Supply Fan Placement
ChilledWater, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule Name
FixedSetpoint, !- Cooling Coil Setpoint Control Type
, !- Cooling Coil Setpoint Schedule Name
12.8, !- Cooling Coil Design Setpoint {C}
15.6, !- Cooling Coil Setpoint at Outdoor Dry-Bulb Low {C}
15.6, !- Cooling Coil Reset Outdoor Dry-Bulb Low {C}
12.8, !- Cooling Coil Setpoint at Outdoor Dry-Bulb High {C}
23.3, !- Cooling Coil Reset Outdoor Dry-Bulb High {C}
autosize, !- DX Cooling Coil Capacity {W}
autosize, !- DX Cooling Coil Rated Sensible Heat Ratio
3, !- DX Cooling Coil Rated COP
HotWater, !- Heating Coil Type
, !- Heating Coil Availability Schedule Name
FixedSetpoint, !- Heating Coil Setpoint Control Type
, !- Heating Coil Setpoint Schedule Name
12.2, !- Heating Coil Design Setpoint {C}
15, !- Heating Coil Setpoint at Outdoor Dry-Bulb Low {C}
7.8, !- Heating Coil Reset Outdoor Dry-Bulb Low {C}
12.2, !- Heating Coil Setpoint at Outdoor Dry-Bulb High {C}
12.2, !- Heating Coil Reset Outdoor Dry-Bulb High {C}
0.8, !- Gas Heating Coil Efficiency
, !- Gas Heating Coil Parasitic Electric Load {W}
Enthalpy, !- Heat Recovery Type
0.7, !- Sensible Heat Recovery Effectiveness
0.65, !- Latent Heat Recovery Effectiveness
Plate, !- Heat Exchanger Type
None, !- Frost Control Type
None, !- Dehumidification Control Type
0.00924, !- Dehumidification Setpoint {kgWater/kgDryAir}
None, !- Humidifier Type
, !- Humidifier Availability Schedule Name
0.000001, !- Humidifier Rated Capacity {m3/s}
2690, !- Humidifier Rated Electric Power {W}
0.003, !- Humidifier Setpoint {kgWater/kgDryAir}
, !- Dehumidification Setpoint Schedule Name
; !- Humidifier Setpoint Schedule Name
HVACTemplate:Plant:ChilledWaterLoop[LINK]
The piping systems that connect the chilled water coils in
the HVAC template objects with the chillers and the cooling
towers (if present) are described with this object. The piping
systems are called loops and this object describes the
controls and pumps on the loops. Only one of these objects may
be defined in an input file and all chilled water coils from
HVAC template objects are served with this object.
The name used to designate the HVACTemplate:Plant:ChilledWaterLoop.
Field: Pump Schedule
Name[LINK]
Leave this field blank if the chilled water and condenser
water pumps are always available. If a schedule name is
specified, those times that the pumps are available should be
specified as 1.0. Those times that the pumps are not available
should have a zero value in the schedule specified. Please
note that this is not a schedule of when the system is
providing chilled water to the coils but a schedule of when it
can provide chilled water to the coils.
Field: Pump Control Type[LINK]
Applies to both chilled water and condenser loop pumps. The
choices for this field are:
The default value is Intermittent.
If the pump control type is Continuous,
the pump will run according to the Pump Schedule (see above)
regardless of whether or not there is a load. If the pump
control type is Intermittent, the pump will
run if a load is sensed and will shut off if there is no load
on the loop.
Field:
Chiller Plant Operation Scheme Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all
times operating in order of Priority specified in HVACTemplate:Plant:Chiller
objects. If a different scheme is to be used to sequence the
chillers, then this entry should be set to User Defined. If
the User Defined option is chosen, then additional EnergyPlus
objects must be included and completely defined in the IDF
file such as shown below depending on the type of plant
operation control scheme chosen:
- PlantEquipmentOperationSchemes
- PlantEquipmentOperation:CoolingLoad
- PlantEquipmentList](page-023.html#plantequipmentlist)
(refer to [HVACTemplate:Plant:Chiller object description for
chiller key name required in this object).
The default value is Default.
Field:
Chiller Plant Equipment Operation Schemes Name[LINK]
This field should contain the name of a [PlantEquipmentOperationSchemes](../input-output-reference/page-023.html#plantequipmentoperationschemes)
object only when the previous field is set to UserDefined. It
is ignored if Chiller Plant Operation Scheme Type is
Default.
Field:
Chilled Water Setpoint Schedule Name[LINK]
Enter the name of a chilled water setpoint schedule that
has values that change at different times of the year. If a
constant set point is needed simply leave this field blank and
the value in the next field will be used at all times. The
values in the schedule are in degrees C. This field is ignored
if the Chilled Water Setpoint Reset Type is something other
than None.
Field: Chilled
Water Design Setpoint[LINK]
Enter the chilled water setpoint temperature to be used for
sizing the chilled water loop and associated equipment in
degrees C. If the Chilled Water Setpoint Schedule is blank and
the Chilled Water Setpoint Reset Type is None, then
this value will be used as the setpoint at all times.
Field: Chilled
Water Pump Configuration[LINK]
The choices for this field are
- VariablePrimaryNoSecondary – variable flow to chillers and
coils
- ConstantPrimaryNoSecondary – constant flow to chillers and
coils with bypass
- ConstantPrimaryVariableSecondary – constant flow to
chillers with bypass, variable flow to coils
- VariablePrimaryConstantSecondary – variable flow to
chillers, constant flow to coils with bypass
The default value is ConstantPrimaryNoSecondary.
The operation of a constant speed pump is fairly
straightforward. If the user designates a constant speed pump
that is operating continuously, the pump will run regardless
of whether or not there is a load. This may have the net
effect of adding heat to the loop if no equipment is turned
on. If the pump is constant speed and operates intermittently,
the pump will run at its capacity if a load is sensed and will
shut off if there is no load on the loop.
A variable speed pump is defined with maximum and minimum
flow rates that are the physical limits of the device. If
there is no load on the loop and the pump is operating
intermittently, then the pump can shutdown. For any other
condition such as the loop having a load and the pump is
operating intermittently or the pump is continuously operating
(regardless of the loading condition), the pump will operate
and select a flow somewhere between the minimum and maximum
limits. In these cases where the pump is running, it will try
to meet the flow request made by demand side components.
Field:
Primary Chilled Water Pump Rated Head[LINK]
The rated head of the primary chilled water pump in Pa. The
default value is 179352 Pa which is equivalent to 60 feet
H2O.
Field:
Secondary Chilled Water Pump Rated Head[LINK]
The rated head of the secondary chilled water pump in Pa.
The default value is 179352 Pa which is equivalent to 60 feet
H2O. This field is applicable only if the “Chilled
Water Pump Configuration” is Constant Primary Variable
Secondary or Variable Primary Constant
Secondary.
Field:
Condenser Plant Operation Scheme Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all
times operating in order of Priority specified in HVACTemplate:Plant:Tower
objects. If a different scheme is to be used to sequence the
towers, then this entry should be set to User Defined. May be
left blank if not serving any water cooled chillers.
If User Defined option is chosen, then additional
EnergyPlus objects must be included and completely defined in
the IDF file such as shown below depending on the type of
condenser operation control scheme chosen:
- CondenserEquipmentOperationSchemes
- PlantEquipmentOperation:CoolingLoad
- PlantEquipmentList](page-023.html#plantequipmentlist)
(refer to the [HVACTemplate:Plant:Tower object description for
key name required for this object.
The default value is Default.
Field:
Condenser Equipment Operation Schemes Name[LINK]
This field should contain the name of a [CondenserEquipmentOperationSchemes](../input-output-reference/page-023.html#condenserequipmentoperationschemes)
object only when the previous field is set to UserDefined. It
is ignored if Condenser Plant Operation Scheme Type is
Default. May be left blank if not serving any water cooled
chillers.
Field:
Condenser Water Temperature Control Type[LINK]
If water cooled chillers are present the condenser water
temperature control can be one of the following options:
- OutdoorWetBulbTemperature
- SpecifiedSetpoint
If a specified set point is used then the towers are
operated to deliver that condenser water set point. If outdoor
wet-bulb is used then the condenser water temperature
decreases with decreasing outdoor wet-bulb temperature. May be
left blank if not serving any water cooled chillers.
Field:
Condenser Water Setpoint Schedule Name[LINK]
Used when Condenser Water Temperature Control Type is set
to Specified Setpoint. Ignored if Condenser Water Temperature
Control Type is set to Outdoor Wet-bulb. The field may be left
blank if constant setpoint temperature is used for the
condenser water temperature. If may also be left blank if not
serving any water cooled chillers. If specified, the schedule
should contain the set point temperatures in degrees C for the
condenser water loop.
Field:
Condenser Water Design Setpoint[LINK]
- Enter the condenser water temperature to be used for
sizing the condenser loop and associated equipment. If a
constant setpoint control is used for the condenser water,
this value will be used as the setpoint at all times. May be
left blank if not serving any water cooled chillers. Used when
Condenser Water Temperature Control Type is set to Specified
Setpoint. Ignored if Condenser Water Temperature Control Type
is set to OutdoorWetBulbTemperature. The units are in C.
Field:
Condenser Water Pump Rated Head[LINK]
The rated head of the condenser water pumps in Pa. May be
left blank if not serving any water cooled chillers. The
default value is 179352 Pa which is equivalent to 60 feet
H2O.
Field:
Chilled Water Setpoint Reset Type[LINK]
Select the type of automatic reset control for the chilled
water supply temperature. The choices are:
- None – no reset, use the Chilled Water Setpoint
Schedule or Chilled Water Design Setpoint.
- OutdoorAirTemperatureReset – reset the chilled
water supply temperature based on the following default rules.
The temperature limits and setpoints are specified using the
fields below. If the default values are used, when the outdoor
dry-bulb temperature (ODB) is at or below 15.6C the setpoint
is 12.2C. When the ODB is at or above 26.7C the setpoint is
6.7C. In between, the setpoint is varied linearly. (Reference
SetpointManager:OutdoorAirReset)
The default is None.
Field:
Chilled Water Setpoint at Outdoor Dry-Bulb Low[LINK]
The chilled water setpoint temperature in C when the
outdoor dry-bulb is at or below the low limit (Chilled Water
Reset Outdoor Dry Bulb Low). The default is 12.2C.
Field:
Chilled Water Reset Outdoor Dry-Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
below this temperature, the setpoint is the value of Chilled
Water Setpoint at Outdoor Dry Bulb Low. The default is
15.6C.
Field:
Chilled Water Setpoint at Outdoor Dry-Bulb High[LINK]
The chilled water setpoint temperature in C when the
outdoor dry-bulb is at or above the high limit (Chilled Water
Reset Outdoor Dry Bulb Low). The default is 6.7C.
Field:
Chilled Water Reset Outdoor Dry-Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
above this temperature, the setpoint is the value of Chilled
Water Setpoint at Outdoor Dry Bulb High. The default is
26.7C.
Field: Chilled
Water Primary Pump Type[LINK]
Describes the type of pump configuration used for the
primary portion of the chilled water loop. The options
include:
- SinglePump
- PumpPerChiller
- TwoHeaderedPumps
- ThreeHeaderedPumps
- FourHeaderedPumps
- FiveHeaderedPumps
Field:
Chilled Water Secondary Pump Type[LINK]
Describes the type of pump configuration used for the
secondary portion of the chilled water loop. The options
include:
- SinglePump
- TwoHeaderedPumps
- ThreeHeaderedPumps
- FourHeaderedPumps
- FiveHeaderedPumps
Field: Condenser
Water Pump Type[LINK]
Describes the type of pump configuration used for the
condenser water loop. The options include:
- SinglePump
- PumpPerTower
- TwoHeaderedPumps
- ThreeHeaderedPumps
- FourHeaderedPumps
- FiveHeaderedPumps
Field:
Chilled Water Supply Side Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is
present in the chilled water loop. The choices for this field
are
Field:
Chilled Water Demand Side Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is
present in the chilled water loop. The choices for this field
are
Field:
Condenser Water Supply Side Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is
present in the condenser water loop. The choices for this
field are
Field:
Condenser Water Demand Side Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is
present in the condenser water loop. The choices for this
field are
Field: Fluid Type[LINK]
This field determines the type of fluid used for the boiler
loop. The following options are available:
- Water
- EthyleneGlycol30
- EthyleneGlycol40
- EthyleneGlycol50
- EthyleneGlycol60
- PropyleneGlycol30
- PropyleneGlycol40
- PropyleneGlycol50
- PropyleneGlycol60
Field: Loop
Design Delta Temperature[LINK]
The temperature difference used in sizing the loop flow
rate. The default is 6.67C.
Field:
Minimum Outdoor Dry Bulb Temperature[LINK]
The minimum outdoor dry bulb temperature that the chilled
water loops operate.
Field:
Chilled Water Load Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to
sequence equipment operation in order to meet the plant loop
demand. Currently, three schemes are functional.
Sequential uses each piece of equipment to
its maximum part load ratio and will operate the last required
piece of equipment between its minimum and maximum part load
ratio in order to meet the loop demand.
Optimal operates each piece of equipment at
its optimal part load ratio and will operate the last
component between its minimum and maximum part load ratio in
order to meet the loop demand. Uniform evenly
distributes the loop demand among all available components on
the equipment list for a given load range.
Field:
Condenser Water Load Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to
sequence equipment operation in order to meet the condenser
loop demand. Currently, three schemes are functional.
Sequential uses each piece of equipment to
its maximum part load ratio and will operate the last required
piece of equipment between its minimum and maximum part load
ratio in order to meet the loop demand.
Optimal operates each piece of equipment at
its optimal part load ratio and will operate the last
component between its minimum and maximum part load ratio in
order to meet the loop demand. Uniform evenly
distributes the loop demand among all available components on
the equipment list for a given load range.
As shown in an IDF:
HVACTemplate:Plant:ChilledWaterLoop,
Chilled Water Loop, !- Plant Loop Name
CoolingPumpAvailSched, !- Pump Schedule
Intermittent, !- Pump Control Type
Default, !- Chiller Plant Operation Scheme Type
, !- Chiller Plant Operation Scheme Name
CW Loop Temp Schedule, !- Chilled Water Setpoint Schedule
7.22, !- Chilled Water Design Setpoint {C}
VariableFlowNoSecondary, !- Chilled Water Pump Configuration
179352, !- Primary Chilled Water Pump Rated Head {Pa}
179352, !- Secondary Chilled Water Pump Rated Head {Pa}
Default, !- Condenser Plant Operation Scheme Type
, !- Condenser Plant Operation Scheme List Name
OutdoorWetBulbTemperature, !- Condenser Water Temperature Control Type
, !- Condenser Water Setpoint Schedule
29.4, !- Condenser Water Design Setpoint {C}
179352, !- Condenser Water Pump Rated Head {Pa}
None, !- Chilled Water Setpoint Reset Type
12.2, !- Chilled Water Setpoint at Outdoor Dry Bulb Low {C}
15.6, !- Chilled Water Reset Outdoor Dry Bulb Low {C}
6.7, !- Chilled Water Setpoint at Outdoor Dry Bulb High {C}
26.7, !- Chilled Water Reset Outdoor Dry Bulb High {C}
SinglePump, !- Chilled Water Primary Pump Type
SinglePump, !- Chilled Water Secondary Pump Type
SinglePump, !- Condenser Water Pump Type
Yes, !- Chilled Water Supply Side Bypass Pipe
Yes, !- Chilled Water Demand Side Bypass Pipe
Yes, !- Condenser Water Supply Side Bypass Pipe
Yes, !- Condenser Water Demand Side Bypass Pipe
Water, !- Fluid Type
6.67, !- Loop Design Delta Temperature {deltaC}
, !- Minimum Outdoor Dry Bulb Temperature {C}
Sequential, !- Chilled Water Load Distribution Scheme
Sequential; !- Condenser Water Load Distribution Scheme
HVACTemplate:Plant:Chiller[LINK]
A chiller or purchased cooling source is described with
this object. To define multiple chillers, use multiple HVACTemplate:Plant:Chiller
objects and use the Sizing Factor field to apportion the total
capacity if autosizing.
The name used to reference the HVACTemplate:Plant:Chiller
object.
Field: Chiller Type[LINK]
While EnergyPlus has a variety of chiller options, the only
choices currently for this field are:
- DistrictChilledWater
- ElectricCentrifugalChiller
- ElectricScrewChiller
- ElectricReciprocatingChiller
The EnergyPlus equipment object types which are used are [DistrictCooling](../input-output-reference/page-024.html#districtcooling)
or [Chiller:Electric:EIR](../input-output-reference/page-024.html#chillerelectriceir).
These equipment type keys must be used if setting up a
user-defined chiller plant operation scheme.
Field: Capacity[LINK]
This field may be set to autosize, which means that the
capacity is based on the peak loads during the design days.
This numeric field contains the design cooling capacity of the
chiller. This capacity should be at the design temperatures
and water flow rates. The units are in W.
Field: Nominal COP[LINK]
This numeric field contains the chiller’s coefficient of
performance. This value should not include
energy use due to pumps, evap-cooled or air-cooled condenser
fans, or cooling tower fans. This Nominal COP should be at the
design temperatures and water flow rates. Not applicable if
Chiller Type is DistrictChilledWater.
Field: Condenser Type[LINK]
The choices for this field are
- AirCooled
- WaterCooled
- EvaporativelyCooled
The default value is WaterCooled. If WaterCooled, then at
least one HVACTemplate:Plant:Tower
object should be defined. Not applicable if Chiller Type is
Purchased Chilled Water.
Field: Priority[LINK]
Enter the priority number of the chiller where 1 is the
highest priority, 2 is just lower, 3 is lower than 2, etc.
This is used if Chiller Plant Operation Scheme Type is set to
Default in HVACTemplate:Plant:ChilledWaterLoop.
Equipment is operated in order of the priority number. This
allows multiple chillers to be sequenced.
Field: Sizing Factor[LINK]
This optional numeric field allows the user to specify a
sizing factor for this component. The sizing factor is used
when the component design inputs are autosized: the autosizing
calculations are performed as usual and the results are
multiplied by the sizing factor. For this component the
chiller object inputs that would be altered by the sizing
factor are: Reference Capacity, Reference Chilled Water Flow
Rate and Reference Condenser Water Flow Rate. Sizing Factor
allows the user to size a component to meet part of the design
load while continuing to use the autosizing feature.
Field: Minimum Part
Load Ratio[LINK]
This numeric field contains the chiller’s minimum part-load
ratio. The expected range is between 0 and 1. Below this
part-load ratio, the compressor cycles on and off to meet the
cooling load. The Minimum Part Load Ratio must be less than or
equal to the Maximum Part Load Ratio. The default value is
0.0.
Field: Maximum Part
Load Ratio[LINK]
This numeric field contains the chiller’s maximum part-load
ratio. This value may exceed 1, but the normal range is
between 0.0 and 1.0. The Maximum Part Load Ratio must be
greater than or equal to the Minimum Part Load Ratio. The
default value is 1.0.
Field: Optimum Part
Load Ratio[LINK]
This numeric field contains the chiller’s optimum part-load
ratio. This is the part-load ratio at which the chiller
performs at its maximum COP. The optimum part-load ratio must
be greater than or equal to the Minimum Part Load Ratio, and
less than or equal to the Maximum Part Load Ratio. The default
value is 1.0.
Field: Minimum
Unloading Ratio[LINK]
This numeric field contains the chiller’s minimum unloading
ratio. The expected range is between 0 and 1. The minimum
unloading ratio is where the chiller capacity can no longer be
reduced by unloading and must be false loaded to meet smaller
cooling loads. A typical false loading strategy is hot-gas
bypass. The minimum unloading ratio must be greater than or
equal to the Minimum Part Load Ratio, and less than or equal
to the Maximum Part Load Ratio. The default value is 0.25.
Field:
Leaving Chilled Water Lower Temperature Limit[LINK]
This numeric field contains the lower limit for the leaving
chilled water temperature in Celsius. This temperature acts as
a cut off for heat transfer in the evaporator, so that the
fluid doesn’t get too cold. The default value is 5˚C.
As shown in an IDF:
HVACTemplate:Plant:Chiller,
District Cooling, !- Chiller Name
ElectricCentrifugalChiller, !- Chiller Type
autosize, !- Capacity {W}
3.2, !- COP
WaterCooled, !- Condenser Type
1, !- Priority
1, !- Sizing Factor
0.1, !- Minimum Part Load Ratio
1.1, !- Maximum Part Load Ratio
0.9, !- Optimum Part Load Ratio
0.2, !- Minimum Unloading Ratio
2; !- Leaving Chilled Water Lower Temperature Limit {C}
HVACTemplate:Plant:Chiller:ObjectReference[LINK]
The name of this object.
Field: Chiller Object
Type[LINK]
The object type of the referenced chiller. Select from one
of the following supported chiller object types:
- Chiller:Electric:EIR
- Chiller:Electric:ReformulatedEIR
Field: Chiller Name[LINK]
The object name of the referenced chiller.
Field: Priority[LINK]
Enter the priority number of the chiller where 1 is the
highest priority, 2 is just lower, 3 is lower than 2, etc.
This is used if Chiller Plant Operation Scheme Type is set to
Default in HVACTemplate:Plant:ChilledWaterLoop.
Equipment is operated in order of the priority number. This
allows multiple chillers to be sequenced.
An example in an IDF:
HVACTemplate:Plant:Chiller:ObjectReference,
Main Chiller Connection, !- Name
Chiller:Electric:EIR, !- Chiller Object Type
Main Chiller, !- Chiller Name
1; !- Priority
HVACTemplate:Plant:Tower[LINK]
A cooling tower is described with this object. To define
multiple cooling towers, use multiple HVACTemplate:Plant:Tower
objects and use the Sizing Factor field to apportion the total
capacity if autosizing.
The name used to reference the HVACTemplate:Plant:Tower
object.
Field: Tower Type[LINK]
The choices for this field are
The EnergyPlus equipment object types which are used are [CoolingTower:SingleSpeed](../input-output-reference/page-026.html#coolingtowersinglespeed)
or [CoolingTower:TwoSpeed](../input-output-reference/page-026.html#coolingtowertwospeed).
These equipment type keys must be used if setting up a
user-defined condenser plant operation scheme.
Field: High-Speed
Nominal Capacity[LINK]
Applicable for Tower Type Single Speed and Two Speed. This
field may be set to autosize. If this field is set to
autosize, then the Low-Speed Nominal Capacity and the Free
Convection Capacity must also be autosized. The units are W.
This numeric input field contains the “nominal” heat rejection
capacity of the cooling tower in watts under high-speed fan
operation, with entering water at 35C (95F), leaving water at
29.4C (85F), entering air at 25.6C (78F) wetbulb and 35C (95F)
drybulb temperatures. The design water flow rate is assumed to
be 5.382E-8 m3/s per watt of high-speed nominal
capacity (3 gpm/ton). 125% of this nominal tower capacity
gives the actual tower heat rejection at these operating
conditions (based on historical assumption that the tower must
dissipate 0.25W of compressor heat for every watt of heat
removed by the evaporator).
Field: High-Speed Fan
Power[LINK]
The tower fan electric consumption when at high speed.
Applicable for Tower Type Single Speed and Two Speed. This
field may be set to autosize. The units are W.
Field: Low-Speed
Nominal Capacity[LINK]
Applicable only for Tower Type Two Speed. This field may be
set to autosize. If this field is set to autosize, then the
High-Speed Nominal Capacity and the Free Convection Capacity
must also be autosized. The units are W. This numeric input
field contains the “nominal” heat rejection capacity of the
cooling tower in watts under low-speed fan operation, with
entering water at 35C (95F), leaving water at 29.4C (85F),
entering air at 25.6C (78F) wetbulb and 35C (95F) drybulb
temperatures. The design water flow rate is assumed to be
5.382E-8 m3/s per watt of high-speed nominal tower
capacity (input field above). 125% of this nominal tower
capacity gives the actual tower heat rejection at these
operating conditions (based on historical assumption that the
tower must dissipate 0.25W of compressor heat for every watt
of heat removed by the evaporator). The value specified for
this field must be greater than zero but less than the value
specified for the field “Tower High-Speed Nominal
Capacity”.
Field: Low-Speed Fan
Power[LINK]
The tower fan electric consumption when at low speed.
Applicable only for Tower Type Two Speed. This field may be
set to autosize. The units are W.
Field: Free Convection
Capacity[LINK]
Applicable for Tower Type Single Speed and Two Speed. This
field may be set to autosize. If this field is set to
autosize, then the High-Speed Nominal Capacity and the
Low-Speed Nominal Capacity must also be autosized. The units
are W. This numeric input field contains the “nominal” heat
rejection capacity of the cooling tower in watts when the
tower is in the “free convection” regime (water flow exists
but tower fan is turned off), with entering water at 35C
(95F), leaving water at 29.4C (85F), entering air at 25.6C
(78F) wetbulb and 35C (95F) drybulb temperatures. The design
water flow rate is assumed to be 5.382E-8 m3/s per
watt of high-speed nominal tower capacity (input field above).
125% of this free convection tower capacity gives the actual
tower heat rejection at these operating conditions (based on
historical assumption that the tower must dissipate 0.25W of
compressor heat for every watt of heat removed by the
evaporator). If the user does not wish to model “free
convection”, then this field should be set to 0.0.
Field: Priority[LINK]
Enter the priority number of the tower where 1 is the
highest priority, 2 is just lower, 3 is lower than 2, etc.
This is used if Condenser Plant Operation Scheme Type is set
to Default in HVACTemplate:Plant:ChilledWaterLoop.
Equipment is operated in order of the priority number. This
allows multiple towers to be sequenced.
Field: Sizing Factor
This optional numeric field allows the user to specify a
sizing factor for this component. The sizing factor is used
when the component design inputs are autosized: the autosizing
calculations are performed as usual and the results are
multiplied by the sizing factor. Sizing factor allows the user
to size a component to meet part of the design load while
continuing to use the autosizing feature.For this component
the tower object inputs that would be altered by the sizing
factor are:
Design Water Flow Rate;
Air Flow Rate at High Fan Speed;
Fan Power at High Fan Speed;
U-Factor Times Area Value at High Fan Speed;
Air Flow Rate at Low Fan Speed (for two-speed tower);
Fan Power at Low Fan Speed (for two-speed tower);
U-Factor Times Area Value at Low Fan Speed (for two-speed
tower);
Air Flow Rate in Free Convection Regime;
U-Factor Times Area Value at Free Convection Air Flow
Rate.
Note that the U-Factor Times Area Value at High Fan Speed
is not multiplied by the Sizing Factor. Instead the
design tower load is multiplied by the sizing factor and the
design UA then calculated as usual. The U-Factor Times Area
Value at Low Fan Speed is set to 60% of the full load design
UA. The U-Factor Times Area Value at Free Convection Air Flow
Rate is set to 10% of the design Tower UA.
An example in an IDF:
HVACTemplate:Plant:Tower,
Main Tower, !- Name
SingleSpeed, !- Tower Type
autosize, !- High Speed Nominal Capacity {W}
autosize, !- High Speed Fan Power {W}
autosize, !- Low Speed Nominal Capacity {W}
autosize, !- Low Speed Fan Power {W}
autosize, !- Free Convection Capacity {W}
1, !- Priority
; !- Sizing Factor
HVACTemplate:Plant:Tower:ObjectReference[LINK]
The name of this object.
Field: Cooling Tower
Object Type[LINK]
The object type of the referenced tower. Select from one of
the following supported tower object types:
- CoolingTower:SingleSpeed
- CoolingTower:TwoSpeed
- CoolingTower:VariableSpeed
Field: Cooling Tower
Name[LINK]
The object name of the referenced tower.
Field: Priority[LINK]
Enter the priority number of the tower where 1 is the
highest priority, 2 is just lower, 3 is lower than 2, etc.
This is used if Condenser Plant Operation Scheme Type is set
to Default in HVACTemplate:Plant:ChilledWaterLoop
or MixedWaterLoop. Equipment is operated in order of the
priority number. This allows multiple towers to be
sequenced.
An example in an IDF:
HVACTemplate:Plant:Tower:ObjectReference,
Main Tower Connection, !- Name
CoolingTower:TwoSpeed, !- Cooling Tower Object Type
Main Tower, !- Cooling Tower Name
1; !- Priority
HVACTemplate:Plant:HotWaterLoop[LINK]
The piping systems that connect the hot water coils in the
HVAC template objects with the boilers are described with this
object. The piping systems are called loops and this object
describes the controls and pumps on the loops. Only one of
these objects should be defined in an input file and all hot
water coils from HVAC template objects are served with this
object.
The name used to designate the HVACTemplate:Plant:HotWaterLoop.
Field: Pump Schedule
Name[LINK]
Leave this field blank if the hot water pump is always
available. If a schedule name is specified, those times that
the pump is available should be specified as 1.0. Those times
that the pump is not available should have a zero value in the
schedule specified. Please note that this is not a schedule of
when the system is providing hot water to the coils but a
schedule of when it can provide hot water to the coils.
Field: Pump Control
Type[LINK]
The choices for this field are
The default value is Intermittent.
If the pump control type is Continuous,
the pump will run according to the Pump Schedule (see above)
regardless of whether or not there is a load. If the pump
control type is Intermittent, the pump will
run if a load is sensed and will shut off if there is no load
on the loop.
Field:
Hot Water Plant Operation Scheme Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all
times operating in order of Priority specified in HVACTemplate:Plant:Boiler
objects. If a different scheme is to be used to sequence the
boilers, then this entry should be set to User Defined.
If User Defined option is chosen, then additional
EnergyPlus objects must be defined in the IDF file such as
shown below depending on the type of plant operation control
scheme chosen:
- PlantEquipmentOperationSchemes
- PlantEquipmentOperation:HeatingLoad
- PlantEquipmentList](page-023.html#plantequipmentlist)
(refer to [HVACTemplate:Plant:Boiler object description for
key name required in this object)
The default value is Default.
Field:
Hot Water Plant Equipment Operation Schemes Name[LINK]
This field should contain the name of a [PlantEquipmentOperationSchemes](../input-output-reference/page-023.html#plantequipmentoperationschemes)
object only when the previous field is set to User Defined. It
is ignored if Hot Water Plant Operation Scheme Type is
Default.
Field: Hot
Water Setpoint Schedule Name[LINK]
Enter the name of a hot water setpoint schedule that has
values that change at different times of the year. If a
constant set point is needed simply leave this field blank and
the value in the next field will be used at all times. The
values in the schedule are in degrees C. This field is ignored
if the Hot Water Setpoint Reset Type is something other than
None.
Field: Hot Water
Design Setpoint[LINK]
Enter the hot water setpoint temperature to be used for
sizing the hot water loop and associated equipment in degrees
C. If the Hot Water Setpoint Schedule is blank and the Hot
Water Setpoint Reset Type is None, then this value
will be used as the setpoint at all times.
Field: Hot Water
Pump Configuration[LINK]
The choices for this field are
- VariableFlow
- ConstantFlow
The default value is ConstantFlow. The variable flow option
simulates a pump with variable flow to boilers and coils,
excess bypassed. The constant flow option simulates constant
flow to boilers and coils, excess bypassed.
The operation of a constant speed pump is fairly
straightforward. If the user designates a constant speed pump
that is operating continuously, the pump will run regardless
of whether or not there is a load. This may have the net
effect of adding heat to the loop if no equipment is turned
on. If the pump is constant speed and operates intermittently,
the pump will run at its capacity if a load is sensed and will
shut off if there is no load on the loop.
A variable speed pump is defined with maximum and minimum
flow rates that are the physical limits of the device. If
there is no load on the loop and the pump is operating
intermittently, then the pump can shutdown. For any other
condition such as the loop having a load and the pump is
operating intermittently or the pump is continuously operating
(regardless of the loading condition), the pump will operate
and select a flow somewhere between the minimum and maximum
limits. In these cases where the pump is running, it will try
to meet the flow request made by demand side components.
Field: Hot Water Pump
Rated Head[LINK]
The rated head of the hot water pump in Pa. The default
value is 179352 Pa which is equivalent to 60 feet H2O.
Field: Hot Water
Setpoint Reset Type[LINK]
Select the type of automatic reset control for the Hot
Water supply temperature. The choices are:
- None – no reset, use the Hot Water Setpoint
Schedule or Hot Water Design Setpoint.
- OutdoorAirTemperatureReset – reset the Hot Water
supply temperature based on the following default rules. The
temperature limits and setpoints are specified using the
fields below. If the default values are used, when the outdoor
dry-bulb temperature (ODB) is at or below –6.7C the setpoint
is 82.2C. When the ODB is at or above 10.0C the setpoint is
65.6C. In between, the setpoint is varied linearly. (Reference
SetpointManager:OutdoorAirReset)
The default is None.
Field:
Hot Water Setpoint at Outdoor Dry Bulb Low[LINK]
The Hot Water setpoint temperature in C when the outdoor
dry-bulb is at or below the low limit (Hot Water Reset Outdoor
Dry Bulb Low). The default is –6.7C.
Field: Hot
Water Reset Outdoor Dry Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
below this temperature, the setpoint is the value of Hot Water
Setpoint at Outdoor Dry Bulb Low. The default is 82.2C.
Field:
Hot Water Setpoint at Outdoor Dry Bulb High[LINK]
The Hot Water setpoint temperature in C when the outdoor
dry-bulb is at or above the high limit (Hot Water Reset
Outdoor Dry Bulb Low). The default is 10.0C.
Field:
Hot Water Reset Outdoor Dry Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for
outdoor air reset control. When the outdoor dry-bulb is at or
above this temperature, the setpoint is the value of Hot Water
Setpoint at Outdoor Dry Bulb High. The default is 65.6C.
Field: Hot Water Pump
Type[LINK]
Describes the type of pump configuration used for the hot
water loop. The options include:
- SinglePump
- PumpPerBoiler
- TwoHeaderedPumps
- ThreeHeaderedPumps
- FourHeaderedPumps
- FiveHeaderedPumps
Field: Supply Side
Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is
present in the hot water loop. The choices for this field
are
Field: Demand Side
Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is
present in the hot water loop. The choices for this field
are
Field: Fluid Type[LINK]
This field determines the type of fluid used for the
chilled water loop. The following options are available:
- Water
- EthyleneGlycol30
- EthyleneGlycol40
- EthyleneGlycol50
- EthyleneGlycol60
- PropyleneGlycol30
- PropyleneGlycol40
- PropyleneGlycol50
- PropyleneGlycol60
Field: Loop
Design Delta Temperature[LINK]
The temperature difference used in sizing the loop flow
rate. The default is 11C.
Field:
Maximum Outdoor Dry Bulb Temperature[LINK]
The maximum outdoor dry bulb temperature that the hot water
loops operate.
Field: Load
Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to
sequence equipment operation in order to meet the plant loop
demand. Currently, three schemes are functional.
Sequential uses each piece of equipment to
its maximum part load ratio and will operate the last required
piece of equipment between its minimum and maximum part load
ratio in order to meet the loop demand.
Optimal operates each piece of equipment at
its optimal part load ratio and will operate the last
component between its minimum and maximum part load ratio in
order to meet the loop demand. Uniform evenly
distributes the loop demand among all available components on
the equipment list for a given load range.
As shown in an IDF:
HVACTemplate:Plant:HotWaterLoop,
Hot Water Loop, !- Plant Loop Name
, !- Pump Schedule
Intermittent, !- Pump Control Type
Default, !- Hot Water Plant Operation Scheme Type
, !- Hot Water Plant Operation Scheme List Name
HW Loop Temp Schedule, !- Hot Water Setpoint Schedule
82, !- Hot Water Design Setpoint {C}
VariableFlow, !- Hot Water Pump Configuration
179352, !- Hot Water Pump Rated Head {Pa}
None, !- Hot Water Setpoint Reset Type
82.2, !- Hot Water Setpoint at Outdoor Dry Bulb Low {C}
-6.7, !- Hot Water Reset Outdoor Dry Bulb Low {C}
65.6, !- Hot Water Setpoint at Outdoor Dry Bulb High {C}
10, !- Hot Water Reset Outdoor Dry Bulb High {C}
SinglePump, !- Hot Water Pump Type
Yes, !- Supply Side Bypass Pipe
Yes, !- Demand Side Bypass Pipe
Water, !- Fluid Type
11, !- Loop Design Delta Temperature {deltaC}
, !- Maximum Outdoor Dry Bulb Temperature {C}
Sequential; !- Load Distribution Scheme
HVACTemplate:Plant:Boiler[LINK]
A boiler or purchased heating source is described with this
object. To define multiple boilers, use multiple HVACTemplate:Plant:Boiler
objects and use the Sizing Factor field to apportion the total
capacity if autosizing.
The name used to reference the HVACTemplate:Plant:Boiler
object.
Field: Boiler Type[LINK]
While EnergyPlus has a variety of boiler options, the only
choices currently for this field are:
- DistrictHotWater
- HotWaterBoiler
The EnergyPlus equipment object types which are used are [DistrictHeating](../input-output-reference/page-024.html#districtheating)
or [Boiler:HotWater](../input-output-reference/page-024.html#boilerhotwater).
These equipment type keys must be used if setting up a
user-defined chiller plant operation scheme.
Field: Capacity[LINK]
This field may be set to autosize, which means that the
capacity is based on the peak loads during the design days.
This numeric field contains the design heating capacity of the
boiler. This capacity should be at the design water flow
rates. The units are in W.
Field: Efficiency[LINK]
This numeric field contains the heating efficiency (as a
fraction between 0 and 1) of the boiler’s burner. Not
applicable if Boiler Type is DistrictHotWater.
Field: Fuel Type[LINK]
The choices for this field are
- Electricity
- NaturalGas
- PropaneGas
- FuelOil#1
- FuelOil#2
- Coal
- Diesel
- Gasoline
- OtherFuel1
- OtherFuel2
Not applicable if Boiler Type is DistrictHotWater
Field: Priority[LINK]
Enter the priority number of the boiler where 1 is the
highest priority, 2 is just lower, 3 is lower than 2, etc.
This is used if Boiler Plant Operation Scheme Type is set to
Default in HVACTemplate:Plant:HotWaterLoop.
Equipment is operated in order of the priority number. This
allows multiple boilers to be sequenced.
Field: Sizing Factor[LINK]
This optional numeric field allows the user to specify a
sizing factor for this component. The sizing factor is used
when the component design inputs are autosized: the autosizing
calculations are performed as usual and the results are
multiplied by the sizing factor. For this component the boiler
object inputs that would be altered by the sizing factor are:
Nominal Capacity and Design Water Flow Rate. Sizing factor
allows the user to size a component to meet part of the design
load while continuing to use the autosizing feature.
Field: Minimum Part
Load Ratio[LINK]
This numeric field contains the minimum part load ratio. If
the ratio of demand to boiler nominal capacity is less than
the minimum part load ratio, then the Min PLR will determine
the operating PLR. The expected range is between 0 and 1. If
this field is left blank, the default value is 0.0.
Field: Maximum Part
Load Ratio[LINK]
This numeric field contains the maximum part load ratio. If
the ratio of demand to boiler nominal capacity is greater than
the maximum part load ratio, then the Max PLR will determine
the operating PLR. This value may exceed 1, but the normal
range is between 0 and 1.1. If this field is left blank, the
default value is 1.1.
Field: Optimum Part
Load Ratio[LINK]
This numeric field contains the optimum part load ratio.
This is the part load ratio at which the boiler performs at
its maximum efficiency. If this field is left blank, the
default value is 1.0.
Field:
Water Outlet Upper Temperature Limit[LINK]
This numeric field contains the outlet temperature upper
limit. If this field is left blank, the default value is
100.0ºC.
An example in an IDF:
HVACTemplate:Plant:Boiler,
Main Boiler, !- Name
HotWaterBoiler, !- Boiler Type
autosize, !- Capacity {W}
0.8, !- Efficiency
NaturalGas, !- Fuel Type
1, !- Priority
1, !- Sizing Factor
0.1, !- Minimum Part Load Ratio
1.1, !- Maximum Part Load Ratio
0.9, !- Optimum Part Load Ratio
99.9; !- Water Outlet Upper Temperature Limit {C}
HVACTemplate:Plant:Boiler:ObjectReference[LINK]
The name of this object.
Field: Boiler Object
Type[LINK]
The object type of the referenced boiler. Select from one
of the following supported boiler object types:
Field: Boiler Name[LINK]
The object name of the referenced boiler.
Field: Priority[LINK]
Enter the priority number of the boiler where 1 is the
highest priority, 2 is just lower, 3 is lower than 2, etc.
This is used if Hot Water Plant Operation Scheme Type is set
to Default in HVACTemplate:Plant:ChilledWaterLoop
or MixedWaterLoop. Equipment is operated in order of the
priority number. This allows multiple boioilers to be
sequenced.
An example in an IDF:
HVACTemplate:Plant:Boiler:ObjectReference,
Main Boiler Connection, !- Name
Boiler:HotWater, !- Boiler Object Type
Main Boiler, !- Boiler Name
1; !- Priority
HVACTemplate:Plant:MixedWaterLoop[LINK]
This object simulates the central plant loop portion of a
water source heat pump system. Often many HVACTemplate:Zone:WaterToAirHeatPump
objects will be used in a building along with a single HVACTemplate:Plant:MixedWaterLoop
that contains one or more cooling towers and boilers. The
piping systems are called loops and this object describes the
controls and pumps on the loops. Only one of these objects
should be defined in an input file.
The name used to designate the HVACTemplate:Plant:MixedWaterLoop.
Field: Pump Schedule
Name[LINK]
Leave this field blank if the water pump is always
available. If a schedule name is specified, those times that
the pump is available should be specified as 1.0. Those times
that the pump is not available should have a zero value in the
schedule specified. Please note that this is not a schedule of
when the system is providing water to the water-to-air heat
pumps but a schedule of when it can provide water to the
water-to-air heat pumps.
Field: Pump Control
Type[LINK]
The choices for this field are
The default value is Intermittent.
If the pump control type is Continuous,
the pump will run according to the Pump Schedule (see above)
regardless of whether or not there is a load. If the pump
control type is Intermittent, the pump will
run if a load is sensed and will shut off if there is no load
on the loop.
Field: Operation Scheme
Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all
times operating in order of Priority specified in HVACTemplate:Plant:Boiler
objects. If a different scheme is to be used to sequence the
boilers, then this entry should be set to User Defined.
If User Defined option is chosen, then additional
EnergyPlus objects must be defined in the IDF file such as
shown below depending on the type of plant operation control
scheme chosen:
- PlantEquipmentOperationSchemes
- PlantEquipmentOperation:CoolingLoad
- PlantEquipmentOperation:HeatingLoad
- PlantEquipmentList](page-023.html#plantequipmentlist)
(refer to [HVACTemplate:Plant:Boiler object description for
key name required in this object)
The default value is Default.
Field:
Equipment Operation Schemes Name[LINK]
This field should contain the name of a [PlantEquipmentOperationSchemes](../input-output-reference/page-023.html#plantequipmentoperationschemes)
object only when the previous field is set to User Defined. It
is ignored if Hot Water Plant Operation Scheme Type is
Default.
Field:
High Temperature Setpoint Schedule Name[LINK]
Enter the name of a high temperature setpoint schedule that
has values that change at different times of the year. If a
constant set point is needed simply leave this field blank and
the value in the next field will be used at all times. The
values in the schedule are in degrees C.
Field: High
Temperature Design Setpoint[LINK]
Enter the high temperature setpoint temperature to be used
for sizing the water loop and associated equipment in degrees
C. If the High Temperature Setpoint Schedule is blank, then
this value will be used as the setpoint at all times. The
default is 33C.
Field:
Low Temperature Setpoint Schedule Name[LINK]
Enter the name of a low temperature setpoint schedule that
has values that change at different times of the year. If a
constant set point is needed simply leave this field blank and
the value in the next field will be used at all times. The
values in the schedule are in degrees C.
Field: Low
Temperature Design Setpoint[LINK]
Enter the low temperature setpoint temperature to be used
for sizing the water loop and associated equipment in degrees
C. If the Low Temperature Setpoint Schedule is blank, then
this value will be used as the setpoint at all times. The
default is 20C.
Field: Water Pump
Configuration[LINK]
The choices for this field are
- VariableFlow
- ConstantFlow
The default value is ConstantFlow. The variable flow option
simulates a pump with variable flow to boilers, cooling
towers, and water to air heat pump, excess bypassed. The
constant flow option simulates constant flow to boilers,
cooling towers, and water to air heat pumps, excess
bypassed.
The operation of a constant speed pump is fairly
straightforward. If the user designates a constant speed pump
that is operating continuously, the pump will run regardless
of whether or not there is a load. This may have the net
effect of adding heat to the loop if no equipment is turned
on. If the pump is constant speed and operates intermittently,
the pump will run at its capacity if a load is sensed and will
shut off if there is no load on the loop.
A variable speed pump is defined with maximum and minimum
flow rates that are the physical limits of the device. If
there is no load on the loop and the pump is operating
intermittently, then the pump can shutdown. For any other
condition such as the loop having a load and the pump is
operating intermittently or the pump is continuously operating
(regardless of the loading condition), the pump will operate
and select a flow somewhere between the minimum and maximum
limits. In these cases where the pump is running, it will try
to meet the flow request made by demand side components.
Field: Water Pump Rated
Head[LINK]
The rated head of the hot water pump in Pa. The default
value is 179352 Pa which is equivalent to 60 feet H2O.
Field: Water Pump Type[LINK]
Describes the type of pump configuration used for mixed
water loop. The options include:
- SinglePump
- PumpPerTowerOrBoiler
- TwoHeaderedPumps
- ThreeHeaderedPumps
- FourHeaderedPumps
- FiveHeaderedPumps
Field: Supply Side
Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is
present in the mixed water loop. The choices for this field
are
Field: Demand Side
Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is
present in the mixed water loop. The choices for this field
are
Field: Fluid Type[LINK]
This field determines the type of fluid used for the mixed
water loop. The following options are available:
- Water
- EthyleneGlycol30
- EthyleneGlycol40
- EthyleneGlycol50
- EthyleneGlycol60
- PropyleneGlycol30
- PropyleneGlycol40
- PropyleneGlycol50
- PropyleneGlycol60
Field: Loop
Design Delta Temperature[LINK]
The temperature difference used in sizing the loop flow
rate. The default is 5.6C.
Field: Load
Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to
sequence equipment operation in order to meet the plant loop
demand. Currently, three schemes are functional.
Sequential uses each piece of equipment to
its maximum part load ratio and will operate the last required
piece of equipment between its minimum and maximum part load
ratio in order to meet the loop demand.
Optimal operates each piece of equipment at
its optimal part load ratio and will operate the last
component between its minimum and maximum part load ratio in
order to meet the loop demand. Uniform evenly
distributes the loop demand among all available components on
the equipment list for a given load range.
As shown in an IDF:
HVACTemplate:Plant:MixedWaterLoop,
Only Water Loop, !- Name
, !- Pump Schedule Name
Intermittent, !- Pump Control Type
Default, !- Operation Scheme Type
, !- Equipment Operation Schemes Name
, !- High Temperature Setpoint Schedule Name
34, !- High Temperature Design Setpoint {C}
, !- Low Temperature Setpoint Schedule Name
20, !- Low Temperature Design Setpoint {C}
ConstantFlow, !- Water Pump Configuration
179352, !- Water Pump Rated Head {Pa}
SinglePump, !- Water Pump Type
Yes, !- Supply Side Bypass Pipe
Yes, !- Demand Side Bypass Pipe
Water, !- Fluid Type
6, !- Loop Design Delta Temperature {deltaC}
Sequential; !- Load Distribution Scheme
Group – HVAC Templates[LINK]
This group of objects allows for the specification of simple zone thermostats and HVAC systems with automatically generated node names. The combinations of HVACTemplate objects are shown below.
For a simple ideal loads system to use for sizing and loads oriented simulations:
HVACTemplate:Thermostat
HVACTemplate:Zone:IdealLoadsAirSystem
For packaged terminal air conditioner (PTAC) systems with optional hot water boiler:
HVACTemplate:Thermostat
HVACTemplate:Zone:PTAC
HVACTemplate:Plant:HotWaterLoop (optional)
HVACTemplate:Plant:Boiler (optional)
For packaged terminal air-to-air heat pump (PTHP) systems:
HVACTemplate:Thermostat
HVACTemplate:Zone:PTHP
For direct-expansion cooling, packaged and split system simulations:
HVACTemplate:Thermostat
HVACTemplate:Zone:Unitary
HVACTemplate:System:Unitary
For direct-expansion heat pump systems:
HVACTemplate:Thermostat
HVACTemplate:Zone:Unitary
HVACTemplate:System:UnitaryHeatPump:AirToAir
For packaged variable air volume systems using direct-expansion cooling:
HVACTemplate:Thermostat
HVACTemplate:Zone:VAV or
HVACTemplate:Zone:VAV:FanPowered
HVACTemplate:System:PackagedVAV
HVACTemplate:Plant:HotWaterLoop
HVACTemplate:Plant:Boiler
For variable air volume systems with boilers and air-cooled chillers:
HVACTemplate:Thermostat
HVACTemplate:Zone:VAV or
HVACTemplate:Zone:VAV:FanPowered
HVACTemplate:System:VAV
HVACTemplate:Plant:ChilledWaterLoop
HVACTemplate:Plant:HotWaterLoop
HVACTemplate:Plant:Chiller
HVACTemplate:Plant:Boiler
For variable air volume systems with boilers and water-cooled chillers, an object related to towers is added:
HVACTemplate:Thermostat
HVACTemplate:Zone:VAV
HVACTemplate:System:VAV or
HVACTemplate:Zone:VAV:FanPowered
HVACTemplate:Plant:ChilledWaterLoop
HVACTemplate:Plant:HotWaterLoop
HVACTemplate:Plant:Chiller
HVACTemplate:Plant:Boiler
HVACTemplate:Plant:Tower
For fan coil systems with boilers and chillers:
HVACTemplate:Thermostat
HVACTemplate:Zone:FanCoil
HVACTemplate:Plant:ChilledWaterLoop
HVACTemplate:Plant:HotWaterLoop
HVACTemplate:Plant:Chiller
HVACTemplate:Plant:Boiler
HVACTemplate:Plant:Tower
For water to air heat pumps with boilers and cooling tower:
HVACTemplate:Thermostat
HVACTemplate:Zone:WaterToAirHeatPump
HVACTemplate:Plant:MixedWaterLoop
HVACTemplate:Plant:Boiler
HVACTemplate:Plant:Tower
For dedicated outdoor air systems (DOAS) combined with a zonal template system:
HVACTemplate:System:DedicatedOutdoorAir
HVACTemplate:Thermostat
One of the following for each zone served by the (DOAS) –
HVACTemplate:Zone:PTAC
HVACTemplate:Zone:PTHP
HVACTemplate:Zone:FanCoil
HVACTemplate:Zone:WaterToAirHeatPump
HVACTemplate:Plant:* objects as needed (depending on the type of zonal system and the type of coils specified in the DOAS system:WaterToAirHeatPump).
The only other HVAC related objects besides the HVACTemplate objects that need to be specified related to HVAC systems are:
This makes the input requirements much smaller but sacrifices some of the flexibility normally found in EnergyPlus.
HVACTemplate:Thermostat[LINK]
Each type of HVAC template zone object may reference one of these HVAC template thermostat objects. Multiple HVAC template zones can reference the same HVAC template thermostat object. The object allows the setpoints to be specified either as a constant for the entire simulation or as schedules. Referenced schedules must be defined elsewhere in the idf. Thermostat control type is dual setpoint with deadband. This object may be omitted and the user may define zone thermostat controls directly using standard EnergyPlus objects ([ZoneControl:Thermostat](../input-output-reference/page-037.html#zonecontrolthermostat) and related objects).
Field: Name[LINK]
A name used to reference this object. This name is referenced by HVACTemplate:Zone objects: i.e., HVACTemplate:Zone:IdealLoadsAirSystem, HVACTemplate:Zone:FanCoil, HVACTemplate:Zone:Unitary, HVACTemplate:Zone:VAV or HVACTemplate:Zone:VAV:FanPowered objects.
Field: Heating Setpoint Schedule Name[LINK]
Enter the name of a heating setpoint schedule that has values that change at different times of the day or year. If a constant set point is needed simply leave this field blank and use the next field. The values in the schedule are in degrees C.
Field: Constant Heating Setpoint[LINK]
Enter the heating setpoint temperature in degrees C if constant throughout the year. If the previous field is used this field should be left blank and will be ignored.
Field: Cooling Setpoint Schedule Name[LINK]
Enter the name of a cooling setpoint schedule that has values that change at different times of the day or year. If a constant set point is needed simply leave this field blank and use the next field. The values in the schedule are in degrees C.
Field: Constant Cooling Setpoint[LINK]
Enter the cooling setpoint temperature in degrees C if constant throughout the year. If the previous field is used this field should be left blank and will be ignored.
As shown in an IDF:
HVACTemplate:Zone:IdealLoadsAirSystem[LINK]
This object provides an ideal system to supply conditioned air to the zone that meets all the load requirements and consumes no energy. It is often used for load calculations, an evaluation where the load components of the building are all that is being investigated, or as the first step to a more realistic model of a building.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:IdealLoadsAirSystem objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
As shown in an IDF:
HVACTemplate:Zone:FanCoil[LINK]
This object simulates a 4 pipe fan coil unit with hot water heating coil, chilled water cooling coil, and an outdoor air mixer. The coils are served directly by HVACTemplate:Plant:ChilledWaterLoop and HVACTemplate:Plant:HotWaterLoop objects. No HVACTemplate:System object is required. Reference [ZoneHVAC:FourPipeFanCoil](../input-output-reference/page-032.html#zonehvacfourpipefancoil) for more details about the fan coil model.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:* objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
Field: Supply Air Maximum Flow Rate[LINK]
By entering Autosize, the maximum supply air flow rate is automatically determined for the zone based on the loads experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday) and cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). Note that the zone must have a thermostat specified in order to autosize the flow rate. If a value is entered it is used as the maximum supply air flow rate into the zone. It will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s.
Field: Zone Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone design heating air flow rate and load will be multiplied by the number input in this field when Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone design cooling air flow rate and load will be multiplied by the number input in this field when Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Outdoor Air Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone), **or Flow/Person, Flow/Area, Sum, Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow as the zone design outdoor air flow rate. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the maximum occupancy to calculate a zone design outdoor air flow rate. Flow/Area means the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area to calculated a zone design outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be added to obtain the zone design outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be used for the zone design outdoor air flow rate. The default is Flow/Person.
DetailedSpecification means that the outdoor air specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object. These objects are referenced in the Design Specification Outdoor Air Object Name and Design Specification [Zone](../input-output-reference/page-011.html#zone) Air Distribution Object Name fields below.
Field: Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone in cubic meters per second. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all [People](../input-output-reference/page-015.html#people) statements assigned to the zone. Occupancy schedule values are not applied. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square meter of floor area (units are m3/s-m2). This input is multiplied by the zone area to obtain a flow rate. This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum.
Field: Outdoor Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic meters per second. This input field is used if Outdoor Air Method is Flow/Zone, Sum or Maximum.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. Fan coil systems are modeled with continuous fan operation, so this is also the supply fan operating schedule. If this field is blank, the schedule has values of 1 for all time periods.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat will go into the air stream and act to cause a temperature rise. Must be between 0 and 1.
Field: Cooling Coil Type[LINK]
There are two coil types available:
Chilled Water uses theCoil:Cooling:Water object with the DetailedAnalysis option. This is the preferred coil model for most applications. ChilledWaterDetailedFlatModel uses the [Coil:Cooling:Water:DetailedGeometry](../input-output-reference/page-042.html#coilcoolingwaterdetailedgeometry) object. This option is available for special applications. The default is ChilledWater.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when cooling is only available seasonally. A schedule value of one indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Coil Design Setpoint[LINK]
This is the design supply air temperature in C used to size the cooling supply air flow and the cooling coil. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 14oC.
Field: Heating Coil Type[LINK]
Only one possible value may be entered here:
Future versions may have additional heating coil types.
Field: Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when heating is only available seasonally. The schedule values denote whether the heating coil can run during a given time period. A schedule value of one indicates that the heating coil can be on during a given time period. A value of zero denotes that the heating coil cannot be used during that time period
Field: Heating Coil Design Setpoint[LINK]
This is the design supply air temperature in C used to size the heating supply air flow and the heating coil. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 50oC.
Field: Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir object if this zone is served by a dedicated outdoor air system (DOAS). When a Dedicated Outdoor Air System Name is entered, the outdoor air flow rate for this zone equipment object will be set to zero and the DOAS will provide the ventilation air to the zone based on the outdoor air specifications in this object. For this fancoil system (ref. ZoneHVAC:FourPipeFanCoil):, the “Capacity Control Method” will be set to CyclingFan if a DOAS system is specified. If this field is blank, then the zone served by this fancoil system will not be served by a DOAS, and the fancoil Capacity Control Method will be ConstantFanVariableFlow.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the cooling design supply air temperature. SupplyAirTemperature means that the field Cooling Coil Design Setpoint will be used for sizing the zone cooling design air flow rate and the cooling coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design supply air temperature and the zone air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is TemperatureDifference. The default is 11.11 deltaC.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the heating design supply air temperature. SupplyAirTemperature means that the field Heating Coil Design Setpoint will be used for sizing the zone heating design air flow rate and the heating coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and zone air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is TemperatureDifference. The default is 30 deltaC.
Field: Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object which specifies the design outdoor air flow rate for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
Field: Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object which specifies the air distribution effectiveness for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:PTAC[LINK]
This object simulates a packaged terminal air conditioner (PTAC) with a DX cooling coil, a heating coil (electric, gas, or hot water), and an outdoor air mixer. The optional hot water heating coil is served directly by HVACTemplate:Plant:HotWaterLoop and HVACTemplate:Plant:Boiler objects. No HVACTemplate:System object is required. Reference [ZoneHVAC:PackagedTerminalAirConditioner](../input-output-reference/page-032.html#zonehvacpackagedterminalairconditioner) for more details about the PTAC model.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:* objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
Field: Cooling Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the DX cooling coil is operating. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered, it will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s. The default is autosize.
Field: Heating Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the heating coil is operating. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered, it will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s. The default is autosize.
Field: No Load Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither cooling nor heating is required (i.e., DX coil and heater are off but the supply air fan operates). This field is only used when the supply air fan operating mode schedule specifies continuous fan operation. Values must be greater than or equal to zero, or this field is autosizable. If the air conditioner’s supply air fan operating mode schedule specifies continuous fan operation and this value is set to zero or this field is left blank, then the model assumes that the supply air flow rate when no cooling/heating is needed is equal to the supply air flow rate when the cooling or heating coil was last operating (for cooling operation or heating operation). By entering Autosize, the supply air flow rate will be sized to match the smaller of the Cooling and Heating flow rates. A value entered in this field will not be multiplied by the sizing factor or by zone multipliers. It is best to autosize or leave blank when using zone multipliers.The units are in m3/s. The default is autosize.
Field: Zone Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone design heating air flow rate and load will be multiplied by the number input in this field when Heating Supply Air Flow Rate is autosized. If this field is left blank, the Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone design cooling air flow rate and load will be multiplied by the number input in this field when Cooling Supply Air Flow Rate is autosized. If this field is left blank, the Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Outdoor Air Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone), **or Flow/Person, Flow/Area, Sum, Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow as the zone design outdoor air flow rate. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the maximum occupancy to calculate a zone design outdoor air flow rate. Flow/Area means the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area to calculated a zone design outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be added to obtain the zone design outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be used for the zone design outdoor air flow rate. The default is Flow/Person.
DetailedSpecification means that the outdoor air specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object. These objects are referenced in the Design Specification Outdoor Air Object Name and Design Specification [Zone](../input-output-reference/page-011.html#zone) Air Distribution Object Name fields below.
Field: Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone in cubic meters per second. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all [People](../input-output-reference/page-015.html#people) statements assigned to the zone. Occupancy schedule values are not applied. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square meter of floor area (units are m3/s-m2). This input is multiplied by the zone area to obtain a flow rate. This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum.
Field: Outdoor Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic meters per second. This input field is used if Outdoor Air Method is Flow/Zone, Sum or Maximum.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. When the fan operating mode schedule indicates continuous fan operation, the fan will operate whenever this schedule is 1.0. If the fan operating schedule indicates cycling fan operation, then fan will only cycle on as needed to meet a load.
Field: Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan operating mode schedule. The supply air fan operating mode may vary during the simulation based on time-of-day or with a change of season. Schedule values of 0 denote that the supply air fan and the heating or cooling coil cycle on and off together to meet the heating or cooling load (a.k.a. AUTO fan). Schedule values other than 0 denote that the supply fan runs continuously while the heating or cooling coil cycles to meet the load. The keywords Cycling or Continuous may also be used to specify a single mode of operation for the entire simulation. The default is Cycling.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the cooling and heating coils. BlowThrough models a system where the supply air fan is before the cooling and heating coils. The default is DrawThrough.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1. The default is 0.7.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa. The default is 75.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1. The default is 0.9.
Field: Cooling Coil Type[LINK]
Enter the type of cooling coil. There is currently only one choices for this field, SingleSpeedDX.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when cooling is only available seasonally. A schedule value of 1.0 indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm determine the cooling coil capacity based on the maximum cooling loads during the cooling design day. If a value is entered, it represents the full load cooling capacity, including both sensible and latent capacity, in watts of the DX coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is autosize.
Field: Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine the sensible heat ratio based on the rated capacity and air flow rate. Otherwise, enter the value of the ratio of the sensible capacity divided by total cooling capacity of the DX cooling coil at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Both the sensible and total cooling capacities used to define the Rated Sensible Heat Ratio (SHR) should be “gross” capacity where the impact of supply air fan heat is NOT included. The default is autosize.
Field: Cooling Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross cooling coil capacity in watts divided by electrical power input in watts of the DX cooling coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 3.0.
Field: Heating Coil Type[LINK]
Enter the type of heating coil. The choices for this field are
If HotWater is specified, then a HVACTemplate:Plant:HotWaterLoop and a HVACTemplate:Plant:Boiler must be included in the input file to serve this hot water coil. The default is Electric.
Field: Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when heating is only available seasonally. The schedule values denote whether the heating coil can run during a given time period. A schedule value of 1.0 indicates that the heating coil can be on during a given time period. A value of zero denotes that the heating coil cannot be used during that time period
Field: Heating Coil Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the coil can deliver in Watts. The default is autosize.
Field: Gas Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default. This field applies only if the heating coil type is gas.
Field: Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas heating coil operation, such as a combustion fan. The units are in W. This field applies only if the heating coil type is gas.
Field: Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir object if this zone is served by a dedicated outdoor air system (DOAS). When a Dedicated Outdoor Air System Name is entered, the outdoor air flow rate for this zone equipment object (ref. ZoneHVAC: PackagedTerminalAirConditioner) will be set to zero and the DOAS will provide the ventilation air to the zone based on the outdoor air specifications in this object. If this field is blank, then the zone served by this PTAC system will not be served by a DOAS.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the cooling design supply air temperature. SupplyAirTemperature means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature will be used for sizing the zone cooling design air flow rate and the cooling coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 14oC.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design supply air temperature and the zone air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is TemperatureDifference. The default is 11.11 deltaC.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the heating design supply air temperature. SupplyAirTemperature means that the field Heating Coil Design Setpoint will be used for sizing the zone heating design air flow rate and the heating coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 50oC.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and zone air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is TemperatureDifference. The default is 30 deltaC.
Field: Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object which specifies the design outdoor air flow rate for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
Field: Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object which specifies the air distribution effectiveness for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:PTHP[LINK]
This object simulates a packaged terminal air-to-air heat pump (PTHP) with a DX cooling coil, a DX air-to-air heat pump heating coil, a supplemental heating coil (electric or gas), and an outdoor air mixer. No HVACTemplate:System object is required. Reference [ZoneHVAC:PackagedTerminalHeatPump](../input-output-reference/page-032.html#zonehvacpackagedterminalheatpump) for more details about the PTHP model.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:* objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
Field: Cooling Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the DX cooling coil is operating. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered, it will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s. The default is autosize.
Field: Heating Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the heating coil is operating. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered, it will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s. The default is autosize.
Field: No Load Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither cooling nor heating is required (i.e., DX coil and heater are off but the supply air fan operates). This field is only used when the supply air fan operating mode schedule specifies continuous fan operation. Values must be greater than or equal to zero, or this field is autosizable. If the air conditioner’s supply air fan operating mode schedule specifies continuous fan operation and this value is set to zero or this field is left blank, then the model assumes that the supply air flow rate when no cooling/heating is needed is equal to the supply air flow rate when the cooling or heating coil was last operating (for cooling operation or heating operation). By entering Autosize, the supply air flow rate will be sized to match the smaller of the Cooling and Heating flow rates. A value entered in this field will not be multiplied by the sizing factor or by zone multipliers. It is best to autosize or leave blank when using zone multipliers. The units are in m3/s. The default is autosize.
Field: Zone Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone design heating air flow rate and load will be multiplied by the number input in this field when Heating Supply Air Flow Rate is autosized. If this field is left blank, the Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone design cooling air flow rate and load will be multiplied by the number input in this field when Cooling Supply Air Flow Rate is autosized. If this field is left blank, the Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Outdoor Air Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone), **or Flow/Person, Flow/Area, Sum, Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow as the zone design outdoor air flow rate. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the maximum occupancy to calculate a zone design outdoor air flow rate. Flow/Area means the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area to calculated a zone design outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be added to obtain the zone design outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be used for the zone design outdoor air flow rate. The default is Flow/Person.
DetailedSpecification means that the outdoor air specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object. These objects are referenced in the Design Specification Outdoor Air Object Name and Design Specification [Zone](../input-output-reference/page-011.html#zone) Air Distribution Object Name fields below.
Field: Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone in cubic meters per second. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all [People](../input-output-reference/page-015.html#people) statements assigned to the zone. Occupancy schedule values are not applied. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square meter of floor area (units are m3/s-m2). This input is multiplied by the zone area to obtain a flow rate. This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum.
Field: Outdoor Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic meters per second. This input field is used if Outdoor Air Method is Flow/Zone, Sum or Maximum.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. When the fan operating mode schedule indicates continuous fan operation, the fan will operate whenever this schedule is 1.0. If the fan operating schedule indicates cycling fan operation, then fan will only cycle on as needed to meet a load.
Field: Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan operating mode schedule. The supply air fan operating mode may vary during the simulation based on time-of-day or with a change of season. Schedule values of 0 denote that the supply air fan and the heating or cooling coil cycle on and off together to meet the heating or cooling load (a.k.a. AUTO fan). Schedule values other than 0 denote that the supply fan runs continuously while the heating or cooling coil cycles to meet the load. The keywords Cycling or Continuous may also be used to specify a single mode of operation for the entire simulation. The default is Cycling.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the cooling and heating coils. BlowThrough models a system where the supply air fan is before the cooling and heating coils. The default is DrawThrough.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1. The default is 0.7.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa. The default is 75.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1. The default is 0.9.
Field: Cooling Coil Type[LINK]
Enter the type of cooling coil. There is currently only one choices for this field, SingleSspeedDX.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when cooling is only available seasonally. A schedule value of 1.0 indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm determine the cooling coil capacity based on the maximum cooling loads during the cooling design day. If a value is entered, it represents the full load cooling capacity, including both sensible and latent capacity, in watts of the DX coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is autosize.
Field: Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine the sensible heat ratio based on the rated capacity and air flow rate. Otherwise, enter the value of the ratio of the sensible capacity divided by total cooling capacity of the DX cooling coil at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Both the sensible and total cooling capacities used to define the Rated Sensible Heat Ratio (SHR) should be “gross” capacity where the impact of supply air fan heat is NOT included. The default is autosize.
Field: Cooling Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross cooling coil capacity in watts divided by electrical power input in watts of the DX cooling coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 3.0.
Field: Heat Pump Heating Coil Type[LINK]
Enter the type of heat pump heating coil. There is currently only one choices for this field, SingleSpeedDXHeatPump.
Field: Heat Pump Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heat pump heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when heating is only available seasonally. A schedule value of 1.0 indicates that the heat pump heating coil can be on during a given time period. A value of zero denotes that the heat pump heating coil cannot be used during that time period.
Field: Heat Pump Heating Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm determine the heat pump heating coil capacity based on the maximum heating loads during the heating design day. If a value is entered, it represents the full load heating capacity, in watts of the DX heat pump unit at rated conditions. Rated conditions are air entering the heat pump heating coil at the heating supply air flow rate at 21.11°C drybulb/15.55°C wetbulb with air entering the outdoor coil at 8.33°C drybulb/6.11C wetbulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is autosize.
Field: Heat Pump Heating Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross heating coil capacity in watts divided by electrical power input in watts of the DX heating coil unit at rated conditions. Rated conditions are air entering the heat pump heating coil at the heating supply air flow rate at 21.11°C drybulb/15.55°C wetbulb with air entering the outdoor coil at 8.33°C drybulb/6.11C wetbulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 2.75.
Field: Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the minimum outdoor dry-bulb temperature in degrees Celsius for PTHP compressor operation. The compressor will not operate (for DX heating or DX cooling) when outdoor dry-bulb temperatures fall below this value. The minimum value must be greater than or equal to -20 °C. The default value is -8°C.
Field: Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the outdoor air dry-bulb temperature above which outdoor coil defrosting is disabled. The temperature for this input field must be greater than or equal to 0 C and less than or equal to 7.22 C. If this input field is left blank, the default value is 5 C.
Field: Heat Pump Defrost Strategy[LINK]
This alpha field has two choices: ReverseCycle or Resistive. If the ReverseCycle strategy is selected, the heating cycle is reversed periodically to provide heat to melt frost accumulated on the outdoor coil. If a Resistive defrost strategy is selected, the frost is melted using an electric resistance heater. If this input field is left blank, the default defrost strategy is ReverseCycle.
Field: Heat Pump Defrost Control[LINK]
This alpha field has two choices: Timed or OnDemand. If Timed control is selected, the defrost time period is calculated based on a fixed value or compressor runtime whether or not frost has actually accumulated. For Timed defrost control, the fractional amount of time the unit is in defrost is entered in the input field “Defrost Time Period Fraction” described below. If OnDemand defrost control is selected, the defrost time period is calculated based on outdoor weather (humidity ratio) conditions. Regardless of which defrost control is selected, defrost does not occur above the user specified outdoor temperature entered in the input field “Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature” described above. If this input field is left blank, the default defrost control is Timed.
Field: Heat Pump Defrost Time Period Fraction[LINK]
This numeric field defines the fraction of compressor runtime when the defrost cycle is active, and only applies to “timed” defrost (see Heat Pump Defrost Control input field above). For example, if the defrost cycle is active for 3.5 minutes for every 60 minutes of compressor runtime, then the user should enter 3.5/60 = 0.058333. The value for this input field must be greater than or equal to 0. If this input field is left blank, the default value is 0.058333.
Field: Supplemental Heating Coil Type[LINK]
Enter the type of supplemental heating coil. The choices for this field are
The default is Electric.
Field: Supplemental Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the supplemental heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when supplemental heating is only available seasonally. The schedule values denote whether the supplemental heating coil can run during a given time period. A schedule value of 1.0 indicates that the supplemental heating coil can be on during a given time period. A value of zero denotes that the supplemental heating coil cannot be used during that time period
Field: Supplemental Heating Coil Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the supplemental heating coil can deliver in Watts. The default is autosize.
Field: Supplemental Heating Coil Maximum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the outdoor air dry-bulb temperature above which the supplemental heating coil is disabled. The temperature for this input field must be less than or equal to 21 C. If this input field is left blank, the default value is 21 C.
Field: Supplemental Gas Heating Coil Efficiency[LINK]
Enter supplemental heating coil gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default. This field applies only if the supplemental heating coil type is gas.
Field: Supplemental Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas supplemental heating coil operation, such as a combustion fan. The units are in W. The default is 0.0. This field applies only if the supplemental heating coil type is gas.
Field: Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir object if this zone is served by a dedicated outdoor air system (DOAS). When a Dedicated Outdoor Air System Name is entered, the outdoor air flow rate for this zone equipment object (ref. [ZoneHVAC:PackagedTerminalHeatPump](../input-output-reference/page-032.html#zonehvacpackagedterminalheatpump)) will be set to zero and the DOAS will provide the ventilation air to the zone based on the outdoor air specifications in this object. If this field is blank, then the zone served by this PTHP system will not be served by a DOAS.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the cooling design supply air temperature. SupplyAirTemperature means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature will be used for sizing the zone cooling design air flow rate and the cooling coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 14oC.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design supply air temperature and the zone air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is TemperatureDifference. The default is 11.11 deltaC.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the heating design supply air temperature. SupplyAirTemperature means that the field Heating Coil Design Setpoint will be used for sizing the zone heating design air flow rate and the heating coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 50oC.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and zone air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is TemperatureDifference. The default is 30 deltaC.
Field: Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object which specifies the design outdoor air flow rate for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
Field: Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object which specifies the air distribution effectiveness for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:Unitary[LINK]
This object simulates the zone portion of a constant volume direct-expansion based HVAC configuration with several different heating options. Often a single HVACTemplate:Zone:Unitary object will be used with a single HVACTemplate:System:Unitary object to simulate single zone direct-expansion based air conditioning systems. In addition, multiple HVACTemplate:Zone:Unitary objects may appear that all reference the same HVACTemplate:System:Unitary object in a multiple zone version. For a multizone system, only one zone is specified as the control zone (see HVACTemplate:System:Unitary for more information). Direct expansion includes single packaged rooftop systems commonly seen in commercial applications and split systems commonly seen in residential applications.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template Unitary System Name[LINK]
Enter the name of the HVACTemplate:System:Unitary object serving this zone.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:* objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
Field: Supply Air Maximum Flow Rate[LINK]
By entering Autosize, the maximum supply air flow rate is automatically determined for the zone based on the loads experienced by the zone during the specified heating SizingPeriod:DesignDay](page-008.html#sizingperioddesignday) and cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). Note that the zone must have a thermostat specified in order to autosize the flow rate, even if it is not the control zone in a multiple zone unitary system. If a value is entered it is used as the maximum supply air flow rate into the zone. It will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The [HVACTemplate:System:Unitary object that is referenced also allows the specification of supply air flow. If the value is specified at the system level it will scale the zone values to match. The units are in m3/s.
Field: Zone Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone design heating air flow rate and load will be multiplied by the number input in this field when Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone design cooling air flow rate and load will be multiplied by the number input in this field when Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Outdoor Air Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone), **or Flow/Person, Flow/Area, Sum, Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow as the zone design outdoor air flow rate. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the maximum occupancy to calculate a zone design outdoor air flow rate. Flow/Area means the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area to calculated a zone design outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be added to obtain the zone design outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be used for the zone design outdoor air flow rate. The default is Flow/Person.
DetailedSpecification means that the outdoor air specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object. These objects are referenced in the Design Specification Outdoor Air Object Name and Design Specification [Zone](../input-output-reference/page-011.html#zone) Air Distribution Object Name fields below.
If the air handler serving this zone serves more than one zone, the total outdoor air flow for the system is the sum of the zone outdoor air flows if the system outdoor air flow is autosized. Since the zones share a single outdoor air source, the amount of outdoor air actually delivered to the zone is based on the fraction of supply air delivered to the zone to the total supply air from the system.
Field: Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone in cubic meters per second. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all [People](../input-output-reference/page-015.html#people) statements assigned to the zone. Occupancy schedule values are not applied. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square meter of floor area (units are m3/s-m2). This input is multiplied by the zone area to obtain a flow rate. This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum.
Field: Outdoor Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic meters per second. This input field is used if Outdoor Air Method is Flow/Zone, Sum or Maximum.
Field: Supply Plenum Name[LINK]
This field allows the user to specify a supply plenum which serves only this zone. The plenum zone is added to the supply air path after the system splitter or system-level supply plenum and before the zone terminal unit. Set to blank if no [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) is to be modeled. If a [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here.
Field: Return Plenum Name[LINK]
This field allows the user to specify a return plenum which serves only this zone. The plenum zone is added to the return air path immediately after the zone and before the system mixer or system-level return plenum. Set to blank if no zone return plenum is to be modeled. If a zone return plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here.
Field: Baseboard Heating Type[LINK]
This field specifies the availability of thermostatically controlled baseboard heat in this zone. The choices are:
The default choice is None.
Field: Baseboard Heating Availability Schedule Name[LINK]
Leave this field blank if you want the baseboard heating to be available for the entire year to perform heating if called for by the thermostat. If a schedule name is specified, those times that the baseboard heating is available should be specified as 1.0. Those times that the basebaord heating is not available should have a zero value in the schedule. Please note that this is not a schedule of when the baseboard is providing heat but a schedule of when it can provide heat.
Field: Baseboard Heating Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the baseboard heating can deliver in Watts. Note that EnergyPlus autosizing will autosize the baseboard heating to meet the full heating load of the zone, regardless of the heating capability of the unitary air handling system. The baseboard heating will be set to heating priority 2, which means it will meet any remaining heating load not met by the unitary system. Prior to v7.1, the capacity was only applied to electric baseboard. Starting with v7.1, the capacity will be used for both hot water and electric baseboard.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the cooling design supply air temperature. SupplyAirTemperature means that the field Zone](page-011.html#zone) Cooling Design Supply Air Temperature will be used for sizing the zone cooling design air flow rate and the cooling coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used. SystemSupplyAirTemperature means that the Cooling Design Supply Air Temperature from the template unitary system serving this zone will be used (Ref. [HVACTemplate:System:Unitary or HVACTemplate:System:UnitaryHeatPump:AirToAir). The default is SystemSupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 12.8°C.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design supply air temperature and the zone air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is TemperatureDifference. The default is 11.11 deltaC.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the heating design supply air temperature. SupplyAirTemperature means that the field Heating Coil Design Setpoint will be used for sizing the zone heating design air flow rate and the heating coil. TemperatureDifference means that the field Zone](page-011.html#zone) Heating Design Supply Air Temperature Difference will be used. SystemSupplyAirTemperature means that the Heating Design Supply Air Temperature from the template unitary system serving this zone will be used (Ref. [HVACTemplate:System:Unitary or HVACTemplate:System:UnitaryHeatPump:AirToAir). The default is SystemSupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 50°C.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and zone air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is TemperatureDifference. The default is 30 deltaC.
Field: Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object which specifies the design outdoor air flow rate for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
Field: Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object which specifies the air distribution effectiveness for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:VAV[LINK]
This object simulates the zone portion of a variable air volume HVAC configuration with several different heating options. Multiple HVACTemplate:Zone:VAV or HVACTemplate:Zone:VAV:FanPowered objects are usually specified for each HVACTemplate:System:VAV object. Reheat is specified at the zone level. Reference [AirTerminal:SingleDuct:VAV:Reheat](../input-output-reference/page-031.html#airterminalsingleductvavreheat) and [AirTerminal:SingleDuct:VAV:NoReheat](../input-output-reference/page-031.html#airterminalsingleductvavnoreheat) for more details about VAV terminal units.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template VAV System Name[LINK]
Enter the name of the HVACTemplate:System:VAV object serving this zone.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:* objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
Field: Supply Air Maximum Flow Rate[LINK]
By entering Autosize, the maximum supply air flow rate is automatically determined for the zone based on the loads experienced by the zone during the specified heating SizingPeriod:DesignDay](page-008.html#sizingperioddesignday) and cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered it is used as the maximum supply air flow rate into the zone. It will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The [HVACTemplate:System:VAV object that is referenced also allows the specification of supply air flow. If the value is specified at the system level it will scale the zone values to match. The units are in m3/s.
Field: Zone Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone design heating air flow rate and load will be multiplied by the number input in this field when Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone design cooling air flow rate and load will be multiplied by the number input in this field when Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Minimum Air Flow Method[LINK]
This field is used to select how the program will determine the minimum flow rate to the zone while the system is operating. There are three choices for selecting how the minimum flow rate is specified: Constant, FixedFlowRate, and Scheduled. If Constant is entered, then the program will use the value for the constant minimum air flow fraction entered in the following field. If FixedFlowRate is entered, then the program will use the value entered in the field below called Fixed Minimum Air Flow Rate. If Scheduled is entered, then the program will obtain the value for minimum flow fraction from the schedule named in the field below called Minimum Air Flow Fraction Schedule Name.
Field: Constant Minimum Air Flow Fraction[LINK]
The minimum flow rate to the zone while the system is operating, specified as a fraction of the maximum air flow rate. The minimum zone fraction is normally specified to meet the minimum ventilation requirement for the occupants. The reheat coil operates only when the damper is at this minimum flow rate when Damper Heating Action is set to Normal (the default). This field is used if the previous field is set to Constant. If the previous field is set to Scheduled (and the field Maximum Hot Water or Steam Flow Rate is set to autosize), then this field is optional and can be used to separately control the air flow rate used for sizing normal-action reheat coils. If this field and the following field have values, the greater of the two is used for sizing.
Field: Fixed Minimum Air Flow Rate[LINK]
The minimum flow rate to the zone while the system is operating, specified as a fixed minimum air flow rate in meters cubed per second. The minimum air flow rate is normally specified to meet the minimum ventilation requirement for the occupants. The reheat coil operates only when the damper is at this minimum flow rate when Damper Heating Action is set to Normal (the default). This field is used if the [Zone](../input-output-reference/page-011.html#zone) Minimum Air Flow Method field is set to FixedFlowRate. If the [Zone](../input-output-reference/page-011.html#zone) Minimum Air Flow Method field is set to Scheduled (and the field Maximum Hot Water or Steam Flow Rate is set to autosize), then this field is optional and can be used to separately control the air flow rate used for sizing normal-action reheat coils. Only one of these two minimum air flow fields (i.e., this field and the previous field) should be used at any time. If this field and the previous field have values, the greater of the two is used for sizing.
Field: Minimum Air Flow Fraction Schedule Name[LINK]
The name of a schedule that determines the value of the minimum air flow fraction. The schedule should contain fractions from 0.0 to 1.0. These values will define the minimum flow rate to the zone while the system is operating, specified as a fraction of the maximum air flow rate. The reheat coil operates only when the damper is at this minimum flow rate when Damper Heating Action is set to Normal (the default). This field is used if the previous field is set to Scheduled. If the previous field is left blank (and the field Maximum Hot Water or Steam Flow Rate is set to autosize), then the air flow rate used for sizing normal-action reheat coils is the average of the minimum and maximum values in this schedule. The air flow rate used for reheat coil sizing is reported with other component sizing information as “Reheat Coil Sizing Air Volume Flow Rate.”
Field: Outdoor Air Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone), **or Flow/Person, Flow/Area, Sum, Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow as the zone design outdoor air flow rate. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the maximum occupancy to calculate a zone design outdoor air flow rate. Flow/Area means the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area to calculated a zone design outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be added to obtain the zone design outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be used for the zone design outdoor air flow rate. The default is Flow/Person.
DetailedSpecification means that the outdoor air specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object. These objects are referenced in the Design Specification Outdoor Air Object Name for Sizing and Design Specification [Zone](../input-output-reference/page-011.html#zone) Air Distribution Object Name fields below.
If the air handler serving this zone serves more than one zone, the total outdoor air flow for the system is the sum of the zone outdoor air flows if the system outdoor air flow is autosized. Since the zones share a single outdoor air source, the amount of outdoor air actually delivered to the zone is based on the fraction of supply air delivered to the zone to the total supply air from the system.
Field: Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone in cubic meters per second. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all [People](../input-output-reference/page-015.html#people) statements assigned to the zone. Occupancy schedule values are not applied. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square meter of floor area (units are m3/s-m2). This input is multiplied by the zone area to obtain a flow rate. This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum.
Field: Outdoor Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic meters per second. This input field is used if Outdoor Air Method is Flow/Zone, Sum or Maximum.
Field: Reheat Coil Type[LINK]
A reheat coil may be added to the VAV box with this field. The choices are:
The default choice is None.
Field: Reheat Coil Availability Schedule Name[LINK]
Leave this field blank if you want the reheat coil to be available for the entire year to perform heating if called for by the thermostat. If a schedule name is specified, those times that the coil is available should be specified as 1.0. Those times that the coil is not available should have a zero value in the schedule specified. Please note that this is not a schedule of when the coil is providing heat but a schedule of when it can provide heat.
Field: Damper Heating Action[LINK]
The VAV box flow rate can be controlled in one of two ways during heating operation:
Under “Normal” operation, the supply air flow into the zone is the minimum air flow rate of the VAV system during heating, essentially acting like a constant volume system during heating. Under “Reverse” the air flow rate through the VAV box may increase above the minimum air flow when the heating demand cannot be satisfied unless greater air flow is provided. The default value is Normal. Reverse action only applies when Reheat Coil Type is HotWater. For electric reheat coils, Normal and Reverse behave the same. For more details, please see the section for [AirTerminal:SingleDuct:VAV:Reheat](../input-output-reference/page-031.html#airterminalsingleductvavreheat).
Control Fields for Maximum Flow During Reheat:[LINK]
The following two fields are used only when Reheat Coil Object Type = [Coil:Heating:Water](../input-output-reference/page-042.html#coilheatingwater) and Damper Heating Action = Reverse. Maximum Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area During Reheat and Maximum Flow Fraction During Reheat are two optional methods to calculate the maximum allowable air flow rate during reheat operation. If both are entered, the greater resulting flow rate is used. If Design Specification Outdoor Air Object Name is also specified, it may increase this limit to meet the outdoor air flow rate requirement. At no time will the maximum flow rate calculated here exceed the value for Maximum Air Flow Rate. This limit is active only when the zone thermostat requests heating and the VAV box damper is reverse acting.
Field: Maximum Flow per Zone Floor Area During Reheat[LINK]
This factor (m3/s-m2) is multiplied by the zone area, to determine the maximum volume flow rate (m3/s) allowed during reheat operation (see detailed explanation above). This field is autocalculatable. If autocalculate is selected, the value is set to 0.002032 m3/s-m2 (0.4 cfm/ft2). If this field and the following field are entered, the greater of the two inputs is used. If this field and the following field are left blank, the maximum flow will not be limited.
Field: Maximum Flow Fraction During Reheat[LINK]
This fraction is multiplied by the Maximum Air Flow Rate to determine the maximum volume flow rate (m3/s) allowed during reheat operation (see detailed explanation above). This field is autocalculatable. If autocalculate is selected, the value is set to 0.002032 m3/s-m2 (0.4 cfm/ft2) multiplied by the zone floor area divided by the Maximum Air Flow Rate. If this field and the previous field are entered, the greater of the two inputs is used. If this field and the previous field are left blank, the maximum flow will not be limited.
Field: Maximum Reheat Air Temperature[LINK]
This field specifies the maximum allowable supply air temperature (°C) leaving the reheat coil in a VAV terminal unit during heating operation. If left blank, there is no limit, and the supply air temperature to the space may become unrealistically high during heating operation. If unknown, a value of 35C (95F) is recommended. There is no default in order to maintain consistency with prior results.
Field: Design Specification Outdoor Air Object Name for Control[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object. When this field is used, the terminal unit will increase flow as needed to meet this outdoor air requirement. If Outdoor Air Flow per Person is non-zero, then the outdoor air requirement will be computed based on the current number of occupants in the zone. At no time will the supply air flow rate exceed the value for Maximum Air Flow Rate. If this field is blank, then the terminal unit will not be controlled for outdoor air flow. See documentation for the zone HVAC outdoor air object for further information (Ref [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object).
Note that this field is used only for specifying the design outdoor air flow rate used for controlling the terminal unit air flow rate. The field Design Specification Outdoor Air Object Name for Sizing (see below) is used to specify the design outdoor air flow rate.
Field: Supply Plenum Name[LINK]
This field allows the user to specify a supply plenum which serves only this zone. The plenum zone is added to the supply air path after the system splitter or system-level supply plenum and before the zone terminal unit. Set to blank if no [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) is to be modeled. If a [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here.
Field: Return Plenum Name[LINK]
This field allows the user to specify a return plenum which serves only this zone. The plenum zone is added to the return air path immediately after the zone and before the system mixer or system-level return plenum. Set to blank if no zone return plenum is to be modeled. If a zone return plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here.
Field: Baseboard Heating Type[LINK]
This field specifies the availability of thermostatically controlled baseboard heat in this zone. The choices are:
The default choice is None.
Field: Baseboard Heating Availability Schedule Name[LINK]
Leave this field blank if you want the baseboard heating to be available for the entire year to perform heating if called for by the thermostat. If a schedule name is specified, those times that the baseboard heating is available should be specified as 1.0. Those times that the basebaord heating is not available should have a zero value in the schedule. Please note that this is not a schedule of when the baseboard is providing heat but a schedule of when it can provide heat.
Field: Baseboard Heating Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the baseboard heating can deliver in Watts. Note that EnergyPlus autosizing will autosize the baseboard heating to meet the full heating load of the zone, regardless of the heating capability of the VAV air handling system. The baseboard heating will be set to heating priority 2, which means it will meet any remaining heating load not met by the VAV system. Prior to v7.1, the capacity was only applied to electric baseboard. Starting with v7.1, the capacity will be used for both hot water and electric baseboard.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the cooling design supply air temperature. SupplyAirTemperature means that the field Zone](page-011.html#zone) Cooling Design Supply Air Temperature will be used for sizing the zone cooling design air flow rate and the cooling coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used. SystemSupplyAirTemperature means that the Cooling Design Supply Air Temperature from the template VAV system serving this zone will be used (Ref. [HVACTemplate:System:VAV or HVACTemplate:System:PackagedVAV). The default is SystemSupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 12.8°C.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design supply air temperature and the zone air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is TemperatureDifference. The default is 11.11 deltaC.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the heating design supply air temperature. SupplyAirTemperature means that the field Heating Coil Design Setpoint will be used for sizing the zone heating design air flow rate and the heating coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 50oC.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and zone air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is TemperatureDifference. The default is 30 deltaC.
Field: Design Specification Outdoor Air Object Name for Sizing[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object which specifies the design outdoor air flow rate for the zone. This field is used only when Outdoor Air Method = DetailedSpecification. Note that this field is used only for specifying the design outdoor air flow rate used for sizing. The field Design Specification Outdoor Air Object Name for Sizing (see above) is used to actively control the VAV terminal air flow rate.
Field: Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object which specifies the air distribution effectiveness for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:VAV:FanPowered[LINK]
This object simulates the zone portion of a variable air volume HVAC configuration with a series or parallel fan powered terminal unit (also know as a powered induction unit or PIU) and several different heating options. Multiple HVACTemplate:Zone:VAV or HVACTemplate:Zone:VAV:FanPowered objects are usually specified for each HVACTemplate:System:VAV object. Reheat is specified at the zone level.
The series powered induction unit is an air system terminal unit that mixes varying amounts of secondary (recirculated) air and primary (conditioned supply) air to produce a fixed flow of air to a zone. The unit contains a small fan that acts to induce the secondary air and a heating coil for heating the mixed secondary and primary air. The fan runs at a constant volume flow rate whenever the unit is on (and the fan’s availability schedule is on or it is activated by an availability manager). With HVACTemplate:Zone:VAV:FanPowered, the secondary fan will operate according to the Availability Schedule and Night Cycle Control specified in the HVACTemplate:System:VAV it is served by.) The fan is downstream of the primary and secondary air inlets. The variable mixing is accomplished by a damper in the unit’s primary air supply inlet duct. This damper can move from fully open (100% primary air. 0% secondary air) to a minimum stop that is specified in the input description. At full cooling the damper will be fully open. At minimum cooling and for heating the damper will be at the minimum stop and the secondary air flow will be at its maximum. Reference object [AirTerminal:SingleDuct:SeriesPIU:Reheat](../input-output-reference/page-031.html#airterminalsingleductseriespiureheat) for more details.
The parallel powered induction unit is an air system terminal unit that mixes varying amounts of secondary (recirculated) air and primary (conditioned supply) air to produce a variable total flow of air to a zone. The unit contains a small fan that acts to induce the secondary air and a heating coil for heating the mixed secondary and primary air. The secondary and primary air streams enter the unit in parallel. The fan sits in the secondary air stream and runs only when the primary air flow is below the Parallel Fan On Flow Fraction and the fan’s availability schedule is on or it is activated by an availability manager. With HVACTemplate:Zone:VAV:FanPowered, the secondary fan will operate according to the Availability Schedule and Night Cycle Control specified in the HVACTemplate:System:VAV it is served by.). The primary air inlet contains a damper that can move from fully open (maximum primary air) to a minimum stop (minimum primary air). At full cooling load the primary air damper is fully open and the fan is off. The primary air flow is at maximum and there is little or no secondary air flow. As the cooling load decreases, the primary air damper gradually closes and the secondary air flow remains close to zero. At some point, usually when the primary air flow has reached the minimum, the fan switches on and secondary air is induced. The heating coil will switch on as needed to meet any heating demand. Reference object [AirTerminal:SingleDuct:ParallelPIU:Reheat](../input-output-reference/page-031.html#airterminalsingleductparallelpiureheat) for more details.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template VAV System Name[LINK]
Enter the name of the HVACTemplate:System:VAV object serving this zone.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:* objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
Field: Primary Supply Air Maximum Flow Rate[LINK]
In a fan powered VAV terminal unit, the primary air flow is the air supplied by the central air handler. By entering Autosize, the maximum primary supply air flow rate is automatically determined for the zone based on the loads experienced by the zone during the specified and cooling SizingPeriod:DesignDay](page-008.html#sizingperioddesignday). If a value is entered it is used as the maximum supply air flow rate into the zone. It will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The [HVACTemplate:System:VAV object that is referenced also allows the specification of supply air flow. If the value is specified at the system level it will scale the zone values to match. The units are in m3/s.
Field: Zone Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone design heating air flow rate and load will be multiplied by the number input in this field when Primary Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone design cooling air flow rate and load will be multiplied by the number input in this field when Primary Supply Air Maximum Flow Rate is autosized. If this field is left blank, the Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Primary Supply Air Minimum Flow Fraction[LINK]
Enter the fraction that the VAV box can reduce to based on the primary supply air maximum flow rate. This field may be sized automatically by entering Autosize.
Field: Secondary Supply Air Maximum Flow Rate[LINK]
In a fan powered VAV terminal unit, the secondary air flow is the air taken from the zone by the terminal unit fan. By entering Autosize, the maximum secondary supply air flow rate is automatically determined for the zone based on the loads experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered, it will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s.
Field: Flow Type[LINK]
This field specifies the type of fan powered unit (PIU). The choices for this field are:
See descriptions of these configurations in the general description for this object, above. For both types, the secondary fan will run according to the System Availability Schedule and Night Cycle Control specified in the HVACTemplate:System:VAV which serves this terminal unit (see Template VAV System above). For Parallel PIU, there is an additional secondary fan control based on the primary air flow fraction (see Parallel Fan On Flow Fraction below).
Field: Parallel Fan On Flow Fraction[LINK]
For parallel PIUs, this field specifies the fraction of the primary air flow at which fan turns on. In the parallel PIU the fan operation is intermittent. If the primary air flow is above this fraction of the maximum, the fan is off. Otherwise the secondary fan will run according to the System Availability Schedule and Night Cycle Control specified in the HVACTemplate:System:VAV which serves this terminal unit. This field does not apply to series PIUs.
Field: Outdoor Air Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone), **or Flow/Person, Flow/Area, Sum, Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow as the zone design outdoor air flow rate. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the maximum occupancy to calculate a zone design outdoor air flow rate. Flow/Area means the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area to calculated a zone design outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be added to obtain the zone design outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be used for the zone design outdoor air flow rate. The default is Flow/Person.
DetailedSpecification means that the outdoor air specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object. These objects are referenced in the Design Specification Outdoor Air Object Name and Design Specification [Zone](../input-output-reference/page-011.html#zone) Air Distribution Object Name fields below.
If the air handler serving this zone serves more than one zone, the total outdoor air flow for the system is the sum of the zone outdoor air flows if the system outdoor air flow is autosized. Since the zones share a single outdoor air source, the amount of outdoor air actually delivered to the zone is based on the fraction of supply air delivered to the zone to the total supply air from the system.
Field: Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone in cubic meters per second. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all [People](../input-output-reference/page-015.html#people) statements assigned to the zone. Occupancy schedule values are not applied. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square meter of floor area (units are m3/s-m2). This input is multiplied by the zone area to obtain a flow rate. This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum.
Field: Outdoor Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic meters per second. This input field is used if Outdoor Air Method is Flow/Zone, Sum or Maximum.
Field: Reheat Coil Type[LINK]
A reheat coil may be added to the VAV box with this field. The choices are:
The default choice is Electric.
Field: Reheat Coil Availability Schedule Name[LINK]
Leave this field blank if you want the reheat coil to be available for the entire year to perform heating if called for by the thermostat. If a schedule name is specified, those times that the coil is available should be specified as 1.0. Those times that the coil is not available should have a zero value in the schedule specified. Please note that this is not a schedule of when the coil is providing heat but a schedule of when it can provide heat.
Field: Fan Total Efficiency[LINK]
Enter the total efficiency of the zone induction fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1.
Field: Fan Delta Pressure[LINK]
Enter the pressure rise of the zone induction fan in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa.
Field: Fan Motor Efficiency[LINK]
Enter the shaft power of the zone induction fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1. Note that the zone fan motor is assumed to be 100% in the air stream.
Field: Supply Plenum Name[LINK]
This field allows the user to specify a supply plenum which serves only this zone. The plenum zone is added to the supply air path after the system splitter or system-level supply plenum and before the zone terminal unit. Set to blank if no [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) is to be modeled. If a [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here.
Field: Return Plenum Name[LINK]
This field allows the user to specify a return plenum which serves only this zone. The plenum zone is added to the return air path immediately after the zone and before the system mixer or system-level return plenum. Set to blank if no zone return plenum is to be modeled. If a zone return plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here.
Field: Baseboard Heating Type[LINK]
This field specifies the availability of thermostatically controlled baseboard heat in this zone. The choices are:
The default choice is None.
Field: Baseboard Heating Availability Schedule Name[LINK]
Leave this field blank if you want the baseboard heating to be available for the entire year to perform heating if called for by the thermostat. If a schedule name is specified, those times that the baseboard heating is available should be specified as 1.0. Those times that the basebaord heating is not available should have a zero value in the schedule. Please note that this is not a schedule of when the baseboard is providing heat but a schedule of when it can provide heat.
Field: Baseboard Heating Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the baseboard heating can deliver in Watts. Note that EnergyPlus autosizing will autosize the baseboard heating to meet the full heating load of the zone, regardless of the heating capability of the VAV air handling system. The baseboard heating will be set to heating priority 2, which means it will meet any remaining heating load not met by the VAV system. Prior to v7.1, the capacity was only applied to electric baseboard. Starting with v7.1, the capacity will be used for both hot water and electric baseboard.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the cooling design supply air temperature. SupplyAirTemperature means that the field Zone](page-011.html#zone) Cooling Design Supply Air Temperature will be used for sizing the zone cooling design air flow rate and the cooling coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used. SystemSupplyAirTemperature means that the Cooling Design Supply Air Temperature from the template VAV system serving this zone will be used (Ref. [HVACTemplate:System:VAV or HVACTemplate:System:PackagedVAV). The default is SystemSupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 12.8°C.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design supply air temperature and the zone air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is TemperatureDifference. The default is 11.11 deltaC.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the heating design supply air temperature. SupplyAirTemperature means that the field Heating Coil Design Setpoint will be used for sizing the zone heating design air flow rate and the heating coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 50oC.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and zone air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is TemperatureDifference. The default is 30 deltaC.
Field: Zone PIU Fan Schedule Name[LINK]
This is the operating schedule for the zone PIU fan. For a parallel PIU, the zone fan operates only when the primary air flow is below the Parallel Fan On Flow Fraction and the [Zone](../input-output-reference/page-011.html#zone) PIU Fan Schedule is on, or when it is activated by an availability manager. For a series PIU, the zone fan operates whenever the [Zone](../input-output-reference/page-011.html#zone) PIU Fan Schedule is on, or it is activated by an availability manager. If this field is left blank, the System Availability Schedule for the HVACTemplate:System serving this zone will be used.
Field: Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object which specifies the design outdoor air flow rate for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
Field: Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object which specifies the air distribution effectiveness for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
As shown in an IDF:
HVACTemplate:Zone:WaterToAirHeatPump[LINK]
This object simulates the zone portion of a water source heat pump system. Often many HVACTemplate:Zone:WaterToAirHeatPump objects will be used in a building along with a single HVACTemplate:Plant:MixedWaterLoop that contains a cooling tower and boiler.
Field: Zone Name[LINK]
Enter the name of the zone. The name must match a building zone name used in the ZONE object.
Field: Template Thermostat Name[LINK]
Enter the name of a HVACTemplate:Thermostat object. Multiple HVACTemplate:Zone:* objects can reference the same HVACTemplate:Thermostat object which makes it easier to revise the thermostat controls for portions of a building.
When this field is blank, it has a special meaning. A blank entry means that traditional thermostat objects referencing the same zone name are used instead of HVACTemplate:Thermostat.
Field: Cooling Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the unit is operating in cooling mode. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered, it will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s. The default is autosize.
Field: Heating Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the unit is operating in heating mode. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). If a value is entered, it will be multiplied by the Supply Air Sizing Factor and by zone multipliers. The units are in m3/s. The default is autosize.
Field: No Load Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither cooling nor heating is required (i.e., the coil is off but the supply air fan operates). This field is only used when the supply air fan operating mode schedule specifies continuous fan operation. Values must be greater than or equal to zero, or this field is autosizable. If the supply air fan operating mode schedule specifies continuous fan operation and this value is set to zero or this field is left blank, then the model assumes that the supply air flow rate when no cooling/heating is needed is equal to the supply air flow rate when the cooling or heating coil was last operating (for cooling operation or heating operation). . By entering Autosize, the supply air flow rate will be sized to match the smaller of the Cooling and Heating flow rates. A value entered in this field will not be multiplied by the sizing factor or by zone multipliers. It is best to autosize or leave blank when using zone multipliers. The units are in m3/s. The default is autosize.
Field: Zone Heating Sizing Factor[LINK]
This input is the zone level heating sizing ratio. The zone design heating air flow rate and load will be multiplied by the number input in this field when Heating Supply Air Flow Rate is autosized. If this field is left blank, the Heating Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Zone Cooling Sizing Factor[LINK]
This input is the zone level cooling sizing ratio. The zone design cooling air flow rate and load will be multiplied by the number input in this field when Cooling Supply Air Flow Rate is autosized. If this field is left blank, the Cooling Sizing Factor from [Sizing:Parameters](../input-output-reference/page-019.html#sizingparameters) will be used.
Field: Outdoor Air Method[LINK]
The input must be either Flow/[Zone](../input-output-reference/page-011.html#zone), **or Flow/Person, Flow/Area, Sum, Maximum or DetailedSpecification. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow as the zone design outdoor air flow rate. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the maximum occupancy to calculate a zone design outdoor air flow rate. Flow/Area means the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area to calculated a zone design outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be added to obtain the zone design outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area and Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) will be used for the zone design outdoor air flow rate. The default is Flow/Person.
DetailedSpecification means that the outdoor air specifications will be taken from a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object and optional [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object. These objects are referenced in the Design Specification Outdoor Air Object Name and Design Specification [Zone](../input-output-reference/page-011.html#zone) Air Distribution Object Name fields below.
Field: Outdoor Air Flow Rate per Person[LINK]
The design outdoor air flow rate per person for this zone in cubic meters per second. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all [People](../input-output-reference/page-015.html#people) statements assigned to the zone. Occupancy schedule values are not applied. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow Rate per Zone Floor Area[LINK]
The design outdoor air volumetric flow rate per square meter of floor area (units are m3/s-m2). This input is multiplied by the zone area to obtain a flow rate. This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum.
Field: Outdoor Air Flow Rate per Zone[LINK]
The design outdoor air flow rate for this zone in cubic meters per second. This input field is used if Outdoor Air Method is Flow/Zone, Sum or Maximum.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. When the fan operating mode schedule indicates continuous fan operation, the fan will operate whenever this schedule is 1.0. If the fan operating schedule indicates cycling fan operation, then fan will only cycle on as needed to meet a load.
Field: Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan operating mode schedule. The supply air fan operating mode may vary during the simulation based on time-of-day or with a change of season. Schedule values of 0 denote that the supply air fan and the heating or cooling coil cycle on and off together to meet the heating or cooling load (a.k.a. AUTO fan). Schedule values other than 0 denote that the supply fan runs continuously while the heating or cooling coil cycles to meet the load. The keywords Cycling or Continuous may also be used to specify a single mode of operation for the entire simulation. The default is Cycling.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the cooling and heating coils. BlowThrough models a system where the supply air fan is before the cooling and heating coils. The default is DrawThrough.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1. The default is 0.7.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa. The default is 75.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1. The default is 0.9.
Field: Cooling Coil Type[LINK]
Enter the type of cooling coil. There is currently only one choices for this field, [Coil:Cooling:WaterToAirHeatPump:EquationFit](../input-output-reference/page-042.html#coilcoolingwatertoairheatpumpequationfit).
Field: Cooling Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm determine the cooling coil capacity based on the maximum cooling loads during the cooling design day. If a value is entered, it represents the full load total cooling capacity, including both sensible and latent capacity, in watts of the DX coil unit at rated conditions (26.7C (80F) entering air dry-bulb temperature, 19.4C (67F) entering air wet-bulb temperature, and 29.4C (85F) entering water temperature). Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is autosize. If a value is specified for this field, it is recommended that the Cooling Coil Rated Sensible Heat Ratio also be specified (see below for more details).
Field: Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine the sensible heat ratio based on the rated capacity and air flow rate. Otherwise, enter the value of the ratio of the sensible capacity divided by total cooling capacity of the DX cooling coil at rated conditions (26.7C (80F) entering air dry-bulb temperature, 19.4C (67F) entering air wet-bulb temperature, and 29.4C (85F) entering water temperature). Both the sensible and total cooling capacities used to define the Rated Sensible Heat Ratio (SHR) should be “gross” capacity where the impact of supply air fan heat is NOT included. The default is autosize. If the Cooling Coil Rated Capacity is autosized, this field should also be autosized (any value specified for Cooling Coil Rate Sensibe Heat Ratio will be ignored). If the Cooling Coil Rated Capacity has a specified value, then this field should also have a specified value. This is because the [Coil:Cooling:WaterToAirHeatPump:EquationFit](../input-output-reference/page-042.html#coilcoolingwatertoairheatpumpequationfit) object has fields for Rated Total Cooling Capacity and Rated Sensible Cooling Capacity. If this field is autosized, a specified value for Cooling Coil Rated Capacity will not be used when the coil object sensible capacity is autosized.
Field: Cooling Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross cooling coil capacity in watts divided by electrical power input in watts of the DX cooling coil unit at rated conditions (26.7C (80F) entering air dry-bulb temperature, 19.4C (67F) entering air wet-bulb temperature, and 29.4C (85F) entering water temperature). The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 3.5.
Field: Heat Pump Heating Coil Type[LINK]
Enter the type of heat pump heating coil. There is currently only one choices for this field, [Coil:Heating:WaterToAirHeatPump:EquationFit](../input-output-reference/page-042.html#coilheatingwatertoairheatpumpequationfit).
Field: Heat Pump Heating Coil Rated Capacity[LINK]
Enter autosize to let the automatic sizing algorithm determine the heat pump heating coil capacity based on the maximum heating loads during the heating design day. If a value is entered, it represents the full load heating capacity, in watts of the DX heat pump unit at rated conditions (21.11C (70F) entering air dry-bulb temperature and 21.11C (70F) entering water temperature). Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is autosize.
Field: Heat Pump Heating Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross heating coil capacity in watts divided by electrical power input in watts of the DX heating coil unit at rated conditions (21.11C (70F) entering air dry-bulb temperature and 21.11C (70F) entering water temperature). The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 4.2.
Field: Supplemental Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when supplemental heating is only available seasonally. The schedule values denote whether the supplemental heating coil can run during a given time period. A schedule value of 1.0 indicates that the supplemental heating coil can be on during a given time period. A value of zero denotes that the supplemental heating coil cannot be used during that time period
Field: Supplemental Heating Coil Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the supplemental heating coil can deliver in Watts. The default is autosize.
Field: Maximum Cycling Rate[LINK]
This numeric field contains the maximum on-off cycling rate for the compressor, which occurs at 50% run time fraction. Suggested values are shown below (Henderson et al. 1999):
Field: Heat Pump Time Constant[LINK]
This numeric field contains the time constant for the cooling coil’s capacity to reach steady state after startup. Suggested values are shown below (Henderson et al. 1999):
Field: Fraction of On-Cycle Power Use[LINK]
This numeric field contains the fraction of on-cycle power use to adjust the part load fraction based on the off-cycle power consumption due to crankcase heaters, controls, fans, and etc. Suggested value values are below (Henderson et al. 1999):
Field: Heat Pump Fan Delay Time[LINK]
This numeric field contains the time delay in seconds for the heat pump supply air fan to shut off after compressor cycle off. This value can be obtained from the manufacturer or the heat pump catalog. Suggested value is 60 seconds. This value is disregared at times when the WaterToAirHeatPump’s fan operating mode schedule value is greater than 0 (i.e., continuous fan mode).
Field: Dedicated Outdoor Air System Name[LINK]
Enter the name of an HVACTemplate:System:DedicatedOutdoorAir object if this zone is served by a dedicated outdoor air system (DOAS). When a Dedicated Outdoor Air System Name is entered, the outdoor air flow rate for this zone equipment object (ref. [ZoneHVAC:WaterToAirHeatPump](../input-output-reference/page-032.html#zonehvacwatertoairheatpump)) will be set to zero and the DOAS will provide the ventilation air to the zone based on the outdoor air specifications in this object. If this field is blank, then the zone served by this water-to-air heat pump system will not be served by a DOAS.
Field: Supplemental Heating Coil Type[LINK]
Enter the type of supplemental heating coil. The choices for this field are
The default is Electric.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the cooling design supply air temperature. SupplyAirTemperature means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature will be used for sizing the zone cooling design air flow rate and the cooling coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 14oC.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between the cooling design supply air temperature and the zone air temperature in degrees Celsius for the zone cooling design air flow rate calculation and cooling coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method is TemperatureDifference. The default is 11.11 deltaC.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
This field selects the method for specifying the heating design supply air temperature. SupplyAirTemperature means that the field Heating Coil Design Setpoint will be used for sizing the zone heating design air flow rate and the heating coil. TemperatureDifference means that the field [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Difference will be used. The default is SupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is SupplyAirTemperature. The default is 50oC.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and zone air temperature in degrees Celsius for the zone heating design air flow rate calculation and heating coil sizing. The absolute value is used, so the sign may be positive or negative. This field is used only when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method is TemperatureDifference. The default is 30 deltaC.
Field: Heat Pump Coil Water Flow Mode[LINK]
This field specifies the way in which water flow through the heat pump coils will be modeled. For this template, WatertoAirHeatPump:EquationFit coil objects are generated and, therefore, there are three options:
Cycling varies water flow through the coil based on the heat pump Part Load Ratio. This control method is appropriate for modeling heat pumps that are outfitted with a soleniod valve which allows water to flow through the coil only when the compressor is active. This is the default for EnergyPlus V8 and later.
Constant provides a constant water flow regardless of heat pump operation. Remember that EnergyPlus has two coils (a heating coil and a cooling coil) to approximate the operation of one coil that can operate in either heating mode or cooling mode. Therefore, when the water flow mode is constant, there will be full flow through either the heating coil or the cooling coil, but not both at the same time.
ConstantOnDemand provides full flow through the coil whenever there is a load. When there is no load, there is zero flow through the coil. This control strategy represents the way EnergyPlus modeled heat pump water flow prior to [Version](../input-output-reference/page-006.html#version) 8.
Field: Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:OutdoorAir](../input-output-reference/page-019.html#designspecificationoutdoorair) object which specifies the design outdoor air flow rate for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
Field: Design Specification Zone Air Distribution Object Name[LINK]
This alpha field specifies the name of a [DesignSpecification:ZoneAirDistribution](../input-output-reference/page-019.html#designspecificationzoneairdistribution) object which specifies the air distribution effectiveness for the zone. This field is used only when Outdoor Air Method = DetailedSpecification.
As shown in an IDF:
HVACTemplate:System:Unitary[LINK]
This object simulates the system portion of a constant volume direct-expansion based HVAC configuration with several different heating options. Often a single HVACTemplate:Zone:Unitary object will be used with a single HVACTemplate:System:Unitary object to simulate single zone direct-expansion based air conditioning systems. In addition, multiple HVACTemplate:Zone:Unitary objects may appear that all reference the same HVACTemplate:System:Unitary object in a multiple zone version. For a multizone system, only one zone is specified as the control zone. Direct expansion includes single packaged rooftop systems commonly seen in commercial buildings and split systems commonly seen in residential buildings.
Field: Name[LINK]
Enter a name for the HVACTemplate:System:Unitary object. This name is used in the HVACTemplate:Zone:Unitary object to reference this system.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. If the “Supply Fan Operating Mode” (see below) is set to Cycling, then this is the supply fan operating schedule. If the fan mode is Cycling this is not a schedule of when the system is providing heating, cooling or air flow but a schedule of when it can provide either heating, cooling, or air flow.
Field: Control Zone or Thermostat Location Name[LINK]
Enter the name of the HVACTemplate:Zone:Unitary object that contains the thermostat. While multiple HVACTemplate:Zone:Unitary objects can be part of a HVACTemplate:System:Unitary system, only one of the zones contains a thermostat that controls heating and cooling operation. For a single zone system, this field should contain the name of that zone.
Field: Supply Fan Maximum Flow Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to the sum of the zone air flow rates. If a value is entered here for the maximum air-flow rate, it is the upper limit on system flow, even if the zone level air flow inputs sum to a greater value. This flow rate will not be multiplied by a sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones. The units are m3/s.
Field: Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan operating mode schedule. The supply air fan operating mode may vary during the simulation based on time-of-day or with a change of season. Schedule values of 0 denote that the supply air fan and the heating or cooling coil cycle on and off together to meet the heating or cooling load (a.k.a. AUTO fan). Schedule values other than 0 denote that the supply fan runs continuously while the heating or cooling coil cycles to meet the load. The keywords Cycling or Continuous may also be used to, specify a single mode of operation for the entire simulation. The default is Cycling.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat will go into the air stream and act to cause a temperature rise. Must be between 0 and 1.
Field: Cooling Coil Type[LINK]
Enter the type of cooling coil. The choices for this field are:
Set this value to “SingleSpeedDX” if you want to simulate a system that provides cooling. You may set this value to “None” if no cooling is desired. The default value is SingleSpeedDX. Future versions may have additional cooling coil types.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when cooling is only available seasonally. A schedule value of 1.0 indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Design Supply Air Temperature[LINK]
Enter the cooling supply air temperature in °C to be used for sizing the cooling coil and zone supply air flow rates. The default is 12.8°C.
Field: Cooling Coil Capacity[LINK]
Enter autosize to let the automatic sizing algorithm determine the cooling coil capacity based on the maximum cooling loads during the cooling design day. If a value is entered, it represents the full load cooling capacity, including both sensible and latent capacity, in watts of the DX coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W.
Field: Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine the sensible heat ratio based on the rated capacity and air flow rate. Otherwise, enter the value of the ratio of the sensible capacity divided by total cooling capacity of the DX cooling coil at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Both the sensible and total cooling capacities used to define the Rated Sensible Heat Ratio (SHR) should be “gross” capacity where the impact of supply air fan heat is NOT included.
Field: Cooling Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross cooling coil capacity in watts divided by electrical power input in watts of the DX cooling coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan.
Field: Heating Coil Type[LINK]
Enter the type of heating used in the unitary system. The choices for this field are
Field: Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when heating is only available seasonally. The schedule values denote whether the heating coil can run during a given time period. A schedule value of 1.0 indicates that the heating coil can be on during a given time period. A value of zero denotes that the heating coil cannot be used during that time period
Field: Heating Design Supply Air Temperature[LINK]
Enter the heating supply air temperature in °C to be used for sizing the heating coil and zone supply air flow rates. The default is 50°C.
Field: Heating Coil Capacity[LINK]
Enter autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the coil can deliver in Watts.
Field: Gas Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default
Field: Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas heating coil operation, such as a combustion fan. The units are in W.
Field: Maximum Outdoor Air Flow Rate[LINK]
Enter autosize or a value for the maximum amount of outdoor air flow into the unit when the economizer is operating. Autosize means that 100% of the full supply flow may be taken from outdoor air. If a value is entered, it is used instead of the autosize value. The units are in m3/s. That is, the entered value is used to define the Maximum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template.
Field: Minimum Outdoor Air Flow Rate[LINK]
Enter autosize or the value for the minimum amount of outdoor air that can enter the unit and be distributed to the zones. Usually this is set to autosize and the value is calculated by the outdoor air requirements of each zone. If a value is entered it overrides the outdoor air specification from the zone level. The units are in m3/s. Note if heat recovery is specified (see Heat Recovery Type below), then a value must be entered in this field, because heat recovery equipment is not yet autosizable. That is, the entered value is used to define the Minimum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template.
Field: Minimum Outdoor Air Schedule Name[LINK]
Leave this field blank if you want the minimum outdoor air to be the same for all hours in the entire year. If a schedule name is specified, values are decimal fractions (0.0 – 1.0) that multiply the minimum outdoor air flow rate. This schedule is useful for reducing the outdoor air flow rate to zero during unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
Choosing NoEconomizer means the economizer will not operate and the outdoor airflow rate will be at the minimum for the entire simulation.
Choosing FixedDryBulb means the economizer will set the outdoor airflow rate at minimum if the outdoor air temperature is higher than a specified dry-bulb temperature limit.
Choosing DifferentialDryBulb will trigger the outdoor airflow to minimum when the dry-bulb temperature of outdoor air is higher than the dry-bulb temperature of the return air.
FixedEnthalpy checks the upper limit of the enthalpy given as a field input against the enthalpy content of outdoor air and will set the outdoor airflow rate to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing but compares the return air enthalpy with the enthalpy of outdoor air. When the enthalpy of outdoor air is greater than the enthalpy of the return air, the outdoor air flow rate is set to minimum.
Choosing ElectronicEnthalpy enables the simulation to calculate the humidity ratio limit of outdoor air based on the dry-bulb temperature of outdoor air and a quadratic/cubic curve, and compare it to the actual outdoor air humidity ratio. If the actual outdoor humidity ratio is greater than the calculated humidity ratio limit, then the outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares both the outdoor dewpoint temperature and the outdoor dry-bulb temperature to their specified high limit values. If either outdoor temperature exceeds the high limit value, the outdoor airflow rate is set to minimum.
Another option DifferentialDryBulbAndEnthalpy enables the control strategy to be based on both the DifferentialDryBulb and DifferentialEnthalpy economizer control strategies.
In addition to all economizer control types listed above, each control type checks for user-entered values for the upper limit of dry-bulb temperature, enthalpy limit, humidity ratio limit and dewpoint limit. The outdoor air flow rate is set to minimum if any of these entered limits are exceeded.
The default for this field is NoEconomizer.
Field: Economizer Lockout[LINK]
Enter one of the following choices for this field:
The default value is NoLockout. The LockoutWithHeating means that if the packaged unit is in heating mode, the economizer is locked out – i.e., the economizer dampers are closed and there is minimum outdoor air flow. LockoutWithCompressor means that in addition to locking out the economizer when the unit is in heating mode the economizer is locked out when the DX unit compressor is on. In other words, when the DX coil is off, the economizer must meet the entire cooling load – it isn’t allowed to operate in conjunction with the DX cooling coil. Similarly, when the DX coil is operating, the economizer is not allowed to operate. The LockoutWithCompressor option is sometimes called a “nonintegrated” economizer.
Field: Economizer Upper Temperature Limit[LINK]
Enter the outdoor air temperature high limit (oC) for economizer operation. If the outdoor air temperature is above this limit, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air temperature high limit control.
Field: Economizer Lower Temperature Limit[LINK]
Enter the outdoor air temperature low limit (oC) for economizer operation. If the outdoor air temperature is below this limit, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air temperature low limit control.
Field: Economizer Upper Enthalpy Limit[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for economizer operation. If the outdoor air enthalpy is above this value, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air enthalpy limit control.
Field: Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC) for economizer operation. If the outdoor air dewpoint temperature is above this value, the outdoor airflow rate will be set to the minimum. This field is required if the Economizer Control Type ‘FixedDewPointAndDryBulb’ has been specified. No input (blank) in this field means that there is no outdoor air dewpoint limit control.
Field: Supply Plenum Name[LINK]
Set to blank if no supply plenum is to be modeled. If a supply plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This supply plenum serves all zones on this system. If any AirLoopHVAC:SupplyPlenums have been specified, the outlet from the system supply plenum will flow through the [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) to the zone terminal unit.
Field: Return Plenum Name[LINK]
Set to blank if no return plenum is to be modeled. If a return plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This return plenum serves all zones on this system. If any zone return plenums have been specified, the return air from the zone will flow through the zone return plenum and then into the system return plenum.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the cooling and heating coils. BlowThrough models a system where the supply air fan is before the cooling and heating coils. The default is BlowThrough.
Field: Night Cycle Control[LINK]
Enter the system behavior during times when the System Availability Schedule is zero (off). The possible inputs are StayOff, CycleOnAny, or CycleOnControl[Zone](../input-output-reference/page-011.html#zone). StayOff means the system will remain off, no matter how hot or cold the zones may be. CycleOnAny means that if any zone served by this system has an air temperature outside the cooling or heating set points the central fan will turn on even though the System Availability Schedule indicates the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone) means the same thing except the availability manager looks at the temperature in only the zone specified in Night Cycle Control [Zone](../input-output-reference/page-011.html#zone) Name. The default is StayOff.
Field: Night Cycle Control Zone Name[LINK]
For the Night Cycle Control option CycleOnControlZone enter the name of the control zone. For other Night Cycle Control options, this field is ignored.
Field: Heat Recovery Type[LINK]
Enter the type of air-to-air heat recovery which is available between the relief air stream and the outdoor air inlet stream. The choices are:
The default is None. If heat recovery is specified (i.e., Sensible or Enthalpy), then a value must be entered in the Minimum Outdoor Air Flow Rate field, because heat recovery equipment is not yet autosizable. The entered Minimum Outdoor Air Flow Rate is used to define the Nominal Supply Air Flow Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent) object generated by this template.
Field: Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.70.
Field: Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat Recovery Type is Enthalpy. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.65.
Field: Dehumidification Control Type[LINK]
There are three dehumidification control type options available:
The CoolReheatHeatingCoil option cools beyond the dry-bulb setpoint as required to meet the humidity setpoint if the system is capable of doing so. Reheat is provided as required by the heating coil. In the simulation, two instances of the heating coil are modeled, one for heating, and one for reheat. The two coil objects represent the same physical coil and never operate simultaneously.
The CollReheatDesuperheater option cools beyond the dry-bulb setpoint as required to meet the humidity setpoint if the system is capable of doing so. Reheat is provided by a desuperheater coil (see object [Coil:Heating:Desuperheater](../input-output-reference/page-042.html#coilheatingdesuperheater)).
The default is None which meets the sensible cooling load only. The humidistat is located in the same zone that is specified above as the Control [Zone](../input-output-reference/page-011.html#zone) or Thermostat Location Name.
Field: Dehumidification Control Zone Name[LINK]
This field is deprecated and will be removed. The humidistat is located in the same zone that is specified above as the Control [Zone](../input-output-reference/page-011.html#zone) or Thermostat Location Name.
Field: Dehumidification Setpoint[LINK]
This field specifies the zone humidistat setpoint for dehumidification in percent (0 to 100). The default is 60%.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric) object. The default is None.
Field: Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the system is operating. If a schedule name is specified, it defines when the humidifier is available. The schedule values denote whether the humidifier can run during a given time period. A schedule value of 1.0 indicates that the humidifier can be on during a given time period. A value of zero denotes that the humidifier cannot be used during that time period
Field: Humidifier Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The humidifier does not currently autosize, so the default is very large to allow for adequate capacity. The default is 0.000001 m3/s.
Field: Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity moisture output. This field can be autosized. When it is autosized, it is calculated from the rated capacity in kg/s and the enthalpy rise in J/kg of the feed water from a reference temperature of liquid water at 20°C to saturated steam at 100°C.
Field: Humidifier Control Zone Name[LINK]
This field specifies the zone name where the humidistat is located for controlling humidification.
Field: Humidifier Setpoint[LINK]
This field specifies the zone humidistat setpoint for humidification in percent (0 to 100). The default is 30%.
As shown in an IDF:
HVACTemplate:System:UnitaryHeatPump:AirToAir[LINK]
This object simulates the system portion of an air to air direct-expansion unitary heat pump. Often a single HVACTemplate:Zone:Unitary object will be used with a single HVACTemplate:System:UnitaryHeatPump:AirToAir object to simulate single zone direct-expansion based heat pump systems. In addition, multiple HVACTemplate:Zone:Unitary objects may appear that all reference the same HVACTemplate:System:UnitaryHeatPump:AirToAir object in a multiple zone version. For a multizone system, only one zone is specified as the control zone. The model can simulate heat pumps seen in commercial buildings and split systems commonly seen in residential buildings.
Field: Name[LINK]
Enter a name for the HVACTemplate:System:UnitaryHeatPump:AirToAir object. This name is used in the HVACTemplate:Zone:Unitary object to reference this system.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. During times when the system is available, the supply fan operating mode controls fan operation. (See “Supply Fan Operating Mode Schedule Name” below)
Field: Control Zone or Thermostat Location Name[LINK]
Enter the name of the HVACTemplate:Zone:Unitary object that contains the thermostat. While multiple HVACTemplate:Zone:Unitary objects can be part of a HVACTemplate:System:UnitaryHeatPump:AirToAir system, only one of the zones contains a thermostat that controls heating and cooling operation. For a single zone system, this field should contain the name of that zone.
Field: Cooling Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the DX cooling coil is operating. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified cooling [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). This flow rate will not be multiplied by a sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones. The units are in m3/s. The default is Autosize.
Field: Heating Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when the heating coil is operating. By entering Autosize, the supply air flow rate is automatically determined based on the loads experienced by the zone during the specified heating [SizingPeriod:DesignDay](../input-output-reference/page-008.html#sizingperioddesignday). This flow rate will not be multiplied by a sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones. The units are in m3/s. The default is Autosize.
Field: No Load Supply Air Flow Rate[LINK]
This field specifies the supply air flow rate when neither cooling nor heating is required (i.e., DX coil and heater are off but the supply air fan operates). This field is only used when the supply air fan operating mode schedule specifies continuous fan operation. Values must be greater than or equal to zero, or this field is autosizable. If the air conditioner’s supply air fan operating mode schedule specifies continuous fan operation and this value is set to zero or this field is left blank, then the model assumes that the supply air flow rate when no cooling/heating is needed is equal to the supply air flow rate when the cooling or heating coil was last operating (for cooling operation or heating operation). By entering Autosize, the supply air flow rate will be sized to match the smaller of the Cooling and Heating flow rates. A value entered in this field will not be multiplied by the sizing factor or by zone multipliers. It is best to autosize or leave blank when using zone multipliers. The units are in m3/s. The default is Autosize.
Field: Supply Fan Operating Mode Schedule Name[LINK]
This field specifies the name of the supply air fan operating mode schedule. The supply air fan operating mode may vary during the simulation based on time-of-day or with a change of season. Schedule values of 0 denote that the supply air fan and the heating or cooling coil cycle on and off together to meet the heating or cooling load (a.k.a. AUTO fan). Schedule values other than 0 denote that the supply fan runs continuously while the heating or cooling coil cycles to meet the load. The keywords Cycling or Continuous may also be used to, specify a single mode of operation for the entire simulation. The default is Cycling.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the dx cooling/heating coil and before the supplemental heating coil. BlowThrough models a system where the supply air fan is before the dx cooling/heating coil and the supplemental heating coil. The default is BlowThrough.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1. The default is 0.7.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20 C at sea level, 101325 Pa. The default is 600 Pa.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater or equal to the Supply Fan Total Efficiency and less than or equal to 1. The default is 0.9.
Field: Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat will go into the air stream and act to cause a temperature rise. Must be between 0 and 1. The default is 1.0.
Field: Cooling Coil Type[LINK]
Enter the type of cooling coil. There is currently only one choices for this field,
SingleSpeedDX. Future versions may have additional cooling coil types.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when cooling is only available seasonally. A schedule value of 1.0 indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Design Supply Air Temperature[LINK]
Enter the cooling supply air temperature in °C to be used for sizing the cooling coil and zone supply air flow rates. The default is 12.8°C.
Field: Cooling Coil Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm determine the cooling coil capacity based on the maximum cooling loads during the cooling design day. If a value is entered, it represents the full load cooling capacity, including both sensible and latent capacity, in watts of the DX coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is Autosize.
Field: Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine the sensible heat ratio based on the rated capacity and air flow rate. Otherwise, enter the value of the ratio of the sensible capacity divided by total cooling capacity of the DX cooling coil at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Both the sensible and total cooling capacities used to define the Rated Sensible Heat Ratio (SHR) should be “gross” capacity where the impact of supply air fan heat is NOT included. The default is Autosize.
Field: Cooling Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross cooling coil capacity in watts divided by electrical power input in watts of the DX cooling coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 3.0.
Field: Heat Pump Heating Coil Type[LINK]
Enter the type of heat pump heating coil. There is currently only one choice for this field, SingleSpeedDXHeatPump.
Field: Heating Design Supply Air Temperature[LINK]
Enter the heating supply air temperature in °C to be used for sizing the heating coil and zone supply air flow rates. The default is 50°C.
Field: Heat Pump Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heat pump heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when heating is only available seasonally. A schedule value of 1.0 indicates that the heat pump heating coil can be on during a given time period. A value of zero denotes that the heat pump heating coil cannot be used during that time period.
Field: Heat Pump Heating Coil Rated Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm determine the heat pump heating coil capacity based on the maximum heating loads during the heating design day. If a value is entered, it represents the full load heating capacity, in watts of the DX heat pump unit at rated conditions. Rated conditions are air entering the heat pump heating coil at the heating supply air flow rate at 21.11°C drybulb/15.55°C wetbulb with air entering the outdoor coil at 8.33°C drybulb/6.11C wetbulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is Autosize.
Field: Heat Pump Heating Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross heating coil capacity in watts divided by electrical power input in watts of the DX heating coil unit at rated conditions. Rated conditions are air entering the heat pump heating coil at the heating supply air flow rate at 21.11°C drybulb/15.55°C wetbulb with air entering the outdoor coil at 8.33°C drybulb/6.11C wetbulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 2.75.
Field: Heat Pump Heating Minimum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the minimum outdoor dry-bulb temperature in degrees Celsius for compressor operation. The compressor will not operate (for DX heating or DX cooling) when outdoor dry-bulb temperatures fall below this value. The minimum value must be greater than or equal to -20 °C. The default value is -8°C.
Field: Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the outdoor air dry-bulb temperature above which outdoor coil defrosting is disabled. The temperature for this input field must be greater than or equal to 0 C and less than or equal to 7.22 C. If this input field is left blank, the default value is 5 C.
Field: Heat Pump Defrost Strategy[LINK]
This alpha field has two choices: ReverseCycle or Resistive. If the ReverseCycle strategy is selected, the heating cycle is reversed periodically to provide heat to melt frost accumulated on the outdoor coil. If a Resistive defrost strategy is selected, the frost is melted using an electric resistance heater. If this input field is left blank, the default defrost strategy is ReverseCycle.
Field: Heat Pump Defrost Control[LINK]
This alpha field has two choices: Timed or OnDemand. If Timed control is selected, the defrost time period is calculated based on a fixed value or compressor runtime whether or not frost has actually accumulated. For Timed defrost control, the fractional amount of time the unit is in defrost is entered in the input field “Defrost Time Period Fraction” described below. If OnDemand defrost control is selected, the defrost time period is calculated based on outdoor weather (humidity ratio) conditions. Regardless of which defrost control is selected, defrost does not occur above the user specified outdoor temperature entered in the input field “Heat Pump Defrost Maximum Outdoor Dry-Bulb Temperature” described above. If this input field is left blank, the default defrost control is Timed.
Field: Heat Pump Defrost Time Period Fraction[LINK]
This numeric field defines the fraction of compressor runtime when the defrost cycle is active, and only applies to “timed” defrost (see Heat Pump Defrost Control input field above). For example, if the defrost cycle is active for 3.5 minutes for every 60 minutes of compressor runtime, then the user should enter 3.5/60 = 0.058333. The value for this input field must be greater than or equal to 0. If this input field is left blank, the default value is 0.058333.
Field: Supplemental Heating Coil Type[LINK]
Enter the type of supplemental heating coil. The choices for this field are
The default is Electric.
Field: Supplemental Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the supplemental heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when supplemental heating is only available seasonally. The schedule values denote whether the supplemental heating coil can run during a given time period. A schedule value of 1.0 indicates that the supplemental heating coil can be on during a given time period. A value of zero denotes that the supplemental heating coil cannot be used during that time period
Field: Supplemental Heating Coil Capacity[LINK]
Enter Autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the supplemental heating coil can deliver in Watts. The default is Autosize.
Field: Supplemental Heating Coil Maximum Outdoor Dry-Bulb Temperature[LINK]
This numeric field defines the outdoor air dry-bulb temperature above which the supplemental heating coil is disabled. The temperature for this input field must be less than or equal to 21 C. If this input field is left blank, the default value is 21 C.
Field: Supplemental Gas Heating Coil Efficiency[LINK]
Enter supplemental heating coil gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default. This field applies only if the supplemental heating coil type is gas.
Field: Supplemental Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas supplemental heating coil operation, such as a combustion fan. The units are in W. The default is 0.0. This field applies only if the supplemental heating coil type is gas.
Field: Maximum Outdoor Air Flow Rate[LINK]
Enter Autosize or a value for the maximum amount of outdoor air flow into the unit when the economizer is operating. Autosize means that 100% of the full supply flow may be taken from outdoor air. The units are in m3/s. That is, the entered value is used to define the Maximum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template.
Field: Minimum Outdoor Air Flow Rate[LINK]
Enter Autosize or the value for the minimum amount of outdoor air that can enter the unit and be distributed to the zones. Usually this is set to autosize and the value is calculated by the outdoor air requirements of each zone. If a value is entered it overrides the outdoor air specification from the zone level. The units are in m3/s. The default is Autosize. Note if heat recovery is specified (see Heat Recovery Type below), then a value must be entered in this field, because heat recovery equipment is not yet autosizable. That is, the entered value is used to define the Minimum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template.
Field: Minimum Outdoor Air Schedule Name[LINK]
Leave this field blank if you want the minimum outdoor air to be the same for all hours in the entire year. If a schedule name is specified, values are decimal fractions (0.0 – 1.0) that multiply the minimum outdoor air flow rate. This schedule is useful for reducing the outdoor air flow rate during unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
Choosing NoEconomizer means the economizer will not operate and the outdoor airflow rate will be at the minimum for the entire simulation.
Choosing FixedDryBulb means the economizer will set the outdoor airflow rate at minimum if the outdoor air temperature is higher than a specified dry-bulb temperature limit.
Choosing DifferentialDryBulb will trigger the outdoor airflow to minimum when the dry-bulb temperature of outdoor air is higher than the dry-bulb temperature of the return air.
FixedEnthalpy checks the upper limit of the enthalpy given as a field input against the enthalpy content of outdoor air and will set the outdoor airflow rate to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing but compares the return air enthalpy with the enthalpy of outdoor air. When the enthalpy of outdoor air is greater than the enthalpy of the return air, the outdoor air flow rate is set to minimum.
Choosing ElectronicEnthalpy enables the simulation to calculate the humidity ratio limit of outdoor air based on the dry-bulb temperature of outdoor air and a quadratic/cubic curve, and compare it to the actual outdoor air humidity ratio. If the actual outdoor humidity ratio is greater than the calculated humidity ratio limit, then the outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares both the outdoor dewpoint temperature and the outdoor dry-bulb temperature to their specified high limit values. If either outdoor temperature exceeds the high limit value, the outdoor airflow rate is set to minimum.
Another option DifferentialDryBulbAndEnthalpy enables the control strategy to be based on both the DifferentialDryBulb and DifferentialEnthalpy economizer control strategies.
In addition to all economizer control types listed above, each control type checks for user-entered values for the upper limit of dry-bulb temperature, enthalpy limit, humidity ratio limit and dewpoint limit. The outdoor air flow rate is set to minimum if any of these entered limits are exceeded.
The default for this field is NoEconomizer
Field: Economizer Lockout[LINK]
Enter one of the following choices for this field:
The default value is NoLockout. The LockoutWithHeating means that if the packaged unit is in heating mode, the economizer is locked out – i.e., the economizer dampers are closed and there is minimum outdoor air flow. LockoutWithCompressor means that in addition to locking out the economizer when the unit is in heating mode the economizer is locked out when the DX unit compressor is on. In other words, when the DX coil is off, the economizer must meet the entire cooling load – it isn’t allowed to operate in conjunction with the DX cooling coil. Similarly, when the DX coil is operating, the economizer is not allowed to operate. The LockoutWithCompressor option is sometimes called a “nonintegrated” economizer.
Field: Economizer Maximum Limit Dry-Bulb Temperature[LINK]
Input for this field is the outdoor air temperature high limit (ºC) for economizer operation. If the outdoor air temperature is above this limit, the outdoor airflow rate will be set to the minimum. This field is required if Economizer Control Type ‘FixedDryBulb’ or ‘FixedDewPointAndDryBulb’ has been specified. No input (blank) in this field means that there is no outdoor air temperature high limit control.
Field: Economizer Maximum Limit Enthalpy[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for economizer operation. If the outdoor air enthalpy is above this value, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air enthalpy limit control.
Field: Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC) for economizer operation. If the outdoor air dewpoint temperature is above this value, the outdoor airflow rate will be set to the minimum. This field is required if the Economizer Control Type ‘FixedDewPointAndDryBulb’ has been specified. No input (blank) in this field means that there is no outdoor air dewpoint limit control.
Field: Economizer Minimum Limit Dry-Bulb Temperature[LINK]
Enter the outdoor air temperature low limit (C) for economizer operation. If the outdoor air temperature is below this limit, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air temperature low limit control.
Field: Supply Plenum Name[LINK]
Set to blank if no supply plenum is to be modeled. If a supply plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This supply plenum serves all zones on this system. If any zone supply plenums have been specified, the outlet from the system supply plenum will flow through the zone supply plenum to the zone terminal unit.
Field: Return Plenum Name[LINK]
Set to blank if no return plenum is to be modeled. If a return plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This return plenum serves all zones on this system. If any zone return plenums have been specified, the return air from the zone will flow through the zone return plenum and then into the system return plenum.
Field: Night Cycle Control[LINK]
Enter the system behavior during times when the System Availability Schedule is zero (off). The possible inputs are StayOff, CycleOnAny, or CycleOnControl[Zone](../input-output-reference/page-011.html#zone). StayOff means the system will remain off, no matter how hot or cold the zones may be. CycleOnAny means that if any zone served by this system has an air temperature outside the cooling or heating set points the central fan will turn on even though the System Availability Schedule indicates the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone) means the same thing except the availability manager looks at the temperature in only the zone specified in Night Cycle Control [Zone](../input-output-reference/page-011.html#zone) Name. The default is StayOff.
Field: Night Cycle Control Zone Name[LINK]
For the Night Cycle Control option CycleOnControlZone enter the name of the control zone. For other Night Cycle Control options, this field is ignored.
Field: Heat Recovery Type[LINK]
Enter the type of air-to-air heat recovery which is available between the relief air stream and the outdoor air inlet stream. The choices are:
The default is None. If heat recovery is specified (i.e., Sensible or Enthalpy), then a value must be entered in the Minimum Outdoor Air Flow Rate field, because heat recovery equipment is not yet autosizable. The entered Minimum Outdoor Air Flow Rate is used to define the Nominal Supply Air Flow Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent) object generated by this template.
Field: Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.70.
Field: Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat Recovery Type is Enthalpy. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.65.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric) object. The default is None.
Field: Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the system is operating. If a schedule name is specified, it defines when the humidifier is available. The schedule values denote whether the humidifier can run during a given time period. A schedule value of 1.0 indicates that the humidifier can be on during a given time period. A value of zero denotes that the humidifier cannot be used during that time period
Field: Humidifier Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The humidifier does not currently autosize, so the default is very large to allow for adequate capacity. The default is 0.000001 m3/s.
Field: Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity moisture output. This field can be autosized. When it is autosized, it is calculated from the rated capacity in kg/s and the enthalpy rise in J/kg of the feed water from a reference temperature of liquid water at 20°C to saturated steam at 100°C.
Field: Humidifier Control Zone Name[LINK]
This field specifies the zone name where the humidistat is located for controlling humidification.
Field: Humidifier Setpoint[LINK]
This field specifies the zone humidistat setpoint for humidification in percent (0 to 100). The default is 30%.
As shown in an IDF:
HVACTemplate:System:VAV[LINK]
This object simulates the system portion of a variable air volume HVAC configuration with several different heating options. Multiple HVACTemplate:Zone:VAV objects are usually specified for each HVACTemplate:System:VAV object.
Field: Name[LINK]
Enter a name for the HVACTemplate:System:VAV object. This name is used in the HVACTemplate:Zone:VAV object to reference this system.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. Please note that for this system type, this is a schedule of when the system is providing air flow.
Field: Supply Fan Maximum Flow Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to the sum of the zone air flow rates. If a value is entered here for the maximum air-flow rate, it is the upper limit on system flow, even if the zone level air flow inputs sum to a greater value. This flow rate will not be multiplied by a sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones. The units are m3/s.
Field: Supply Fan Minimum Flow Rate[LINK]
Enter the minimum supply air volume that may be provided. This field may be set to autosize. The units are in m3/s.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa.
Field: Supply Fan Motor efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat will go into the air stream and act to cause a temperature rise. Must be between 0 and 1.
Field: Cooling Coil Type[LINK]
There are two coil types available:
ChilledWater uses the COIL:Cooling:Water object with the DetailedAnalysis option. This is the preferred coil model for most applications. ChilledWaterDetailedFlatModel uses the [Coil:Cooling:Water:DetailedGeometry](../input-output-reference/page-042.html#coilcoolingwaterdetailedgeometry) object. This option is available for special applications. The default is ChilledWater.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when cooling is only available seasonally. A schedule value of one indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the cooling coil is to be specified, leave this field blank, and the Cooling Coil Design Setpoint value will be used at all times. If a set point schedule is to be used for the cooling coil specify the schedule name here. The schedule should control the supply air temperature delivered to the zones. For Blow Through fan placement, this is the leaving air temperature from the cooling coil. For Draw Through fan placement, this is the leaving air temperature after the supply fan. The values in the schedule are in degrees C. This field is ignored if the Cooling Coil Setpoint Reset Type is something other than None (see below).
Field: Cooling Coil Design Setpoint[LINK]
Enter the cooling supply air temperature in C to be used for sizing the cooling coil and zone supply air flow rates. The default is 12.8C. If no Cooling Coil Setpoint Schedule or Cooling Coil Setpoint Reset Type is specified, this value is used as a constant cooling supply air setpoint temperature.
Field: Heating Coil Type[LINK]
The heating coil is located in the supply air stream, upstream of the cooling coil and after the outdoor air mixing box. If no central heating coil is used in the VAV system, then the option “none” should be specified here. Otherwise this indicates the type of heating coil. It is unlikely that both a heating coil and a preheat coil would be used at the same time. The choices for this field are
The default value is None. Note that the configuration of HVACTemplate:System:VAV assumes that there will be reheat coils or baseboard heating to provide heating control at the zone level. If a heating coil is specified, the heating and cooling coil setpoint controls and availability schedules must coordinate to prevent the coils from opposing each other.
Field: Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when heating is only available seasonally. The schedule values denote whether the heating coil can run during a given time period. A schedule value of one indicates that the heating coil can be on during a given time period. A value of zero denotes that the heating coil cannot be used during that time period
Field: Heating Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the heating coil is to be specified, leave this field blank, and the Heating Coil Design Setpoint value will be used at all times. If a set point schedule is to be used for the heating coil specify the schedule name here. The schedule should control the supply air temperature delivered to the zones. For Blow Through fan placement, this is the leaving air temperature from the heating coil. For Draw Through fan placement, this is the leaving air temperature after the supply fan. The values in the schedule are in degrees C. This field is ignored if the Heating Coil Setpoint Reset Type is something other than None (see below).
Field: Heating Coil Design Setpoint[LINK]
Enter the heating supply air temperature in C to be used for sizing the heating coil and zone supply air flow rates. If no Heating Coil Setpoint Schedule or Heating Coil Setpoint Reset Type is specified, this value is used as a constant heating supply air setpoint temperature. The default is 10.0C.
Field: Gas Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default
Field: Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas heating operation, such as a combustion fan. The units are in W.
Field: Preheat Coil Type[LINK]
The preheat coil is located in the outdoor air stream, upstream of the outdoor air mixing box and tempers the outdoor air. If no preheat coil is used in the VAV system, then the option “none” should be specified here. Otherwise this indicates the type of preheat coil. It is unlikely that both a heating coil and a preheat coil would be used at the same time. The choices for this field are
The default value is None. If a preheat coil is specified, the preheat and cooling coil setpoint controls and availability schedules must coordinate to prevent the coils from opposing each other.
Field: Preheat Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the preheat coil to be available anytime the system is operating. If a schedule name is specified, it defines when the preheat coil is available. This is most often used when preheat is only available seasonally. The schedule values denote whether the preheat coil can run during a given time period. A schedule value of 1.0 indicates that the preheat coil can be on during a given time period. A value of zero denotes that the preheat coil cannot be used during that time period
Field: Preheat Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the preheat coil is to be specified, leave this field blank, and the Preheat Coil Design Setpoint value will be used at all times. If a set point schedule is to be used for the preheat coil specify the schedule name here. The schedule should control the leaving air temperature from the preheat coil. The values in the schedule are in degrees C.
Field: Preheat Coil Design Setpoint[LINK]
Enter the preheat supply air temperature in C to be used for sizing the preheat coil. If no Preheat Coil Setpoint Schedule is specified, this value is used as a constant preheat supply air setpoint temperature. The default is 7.2C.
Field: Gas Preheat Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default
Field: Gas Preheat Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas heating operation, such as an combustion fan. The units are in W.
Field: Maximum Outdoor Air Flow Rate[LINK]
Enter autosize or a value for the maximum amount of outdoor air flow into the unit when the economizer is operating. Autosize means that 100% of the full supply flow may be taken from outdoor air. If a value is entered, it is used instead of the autosize value. The units are in m3/s. That is, the entered value is used to define the Maximum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template.
Field: Minimum Outdoor Air Flow Rate[LINK]
Enter autosize or the value for the minimum amount of outdoor air that can enter the unit and be distributed to the zones. Usually this is set to autosize and the value is calculated by the outdoor air requirements of each zone. If a value is entered it overrides the outdoor air specification from the zone level. The units are in m3/s. Note if heat recovery is specified (see Heat Recovery Type below), then a value must be entered in this field, because heat recovery equipment is not yet autosizable. That is, the entered value is used to define the Minimum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template.
Field: Minimum Outdoor Air Control Type[LINK]
Choices for this field are FixedMinimum or ProportionalMinimum. FixedMinimum means that the minimum outdoor air flow rate is fixed no matter what the actual system flow rate is. ProportionalMinimum means the minimum outdoor air flow rate varies in proportion to the total system air flow rate. The default is ProportionalMinimum.
Field: Minimum Outdoor Air Schedule Name Name[LINK]
Leave this field blank if you want the minimum outdoor air to be the same for all hours in the entire year. If a schedule name is specified, values are decimal fractions (0.0 – 1.0) that multiply the minimum outdoor air flow rate. This schedule is useful for reducing the outdoor air flow rate to zero during unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
Choosing NoEconomizer means the economizer will not operate and the outdoor airflow rate will be at the minimum for the entire simulation.
Choosing FixedDryBulb means the economizer will set the outdoor airflow rate at minimum if the outdoor air temperature is higher than a specified dry-bulb temperature limit.
Choosing DifferentialDryBulb will trigger the outdoor airflow to minimum when the dry-bulb temperature of outdoor air is higher than the dry-bulb temperature of the return air.
FixedEnthalpy checks the upper limit of the enthalpy given as a field input against the enthalpy content of outdoor air and will set the outdoor airflow rate to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing but compares the return air enthalpy with the enthalpy of outdoor air. When the enthalpy of outdoor air is greater than the enthalpy of the return air, the outdoor air flow rate is set to minimum.
Choosing ElectronicEnthalpy enables the simulation to calculate the humidity ratio limit of outdoor air based on the dry-bulb temperature of outdoor air and a quadratic/cubic curve, and compare it to the actual outdoor air humidity ratio. If the actual outdoor humidity ratio is greater than the calculated humidity ratio limit, then the outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares both the outdoor dewpoint temperature and the outdoor dry-bulb temperature to their specified high limit values. If either outdoor temperature exceeds the high limit value, the outdoor airflow rate is set to minimum.
Another option DifferentialDryBulbAndEnthalpy enables the control strategy to be based on both the DifferentialDryBulb and DifferentialEnthalpy economizer control strategies.
In addition to all economizer control types listed above, each control type checks for user-entered values for the upper limit of dry-bulb temperature, enthalpy limit, humidity ratio limit and dewpoint limit. The outdoor air flow rate is set to minimum if any of these entered limits are exceeded.
The default for this field is NoEconomizer.
Field: Economizer Lockout[LINK]
The only choice for this field is
The default value is NoLockout. Future versions may have additional options.
Field: Economizer Upper Temperature Limit[LINK]
Enter the outdoor air temperature high limit (oC) for economizer operation. If the outdoor air temperature is above this limit, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air temperature high limit control.
Field: Economizer Lower Temperature Limit[LINK]
Enter the outdoor air temperature low limit (oC) for economizer operation. If the outdoor air temperature is below this limit, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air temperature low limit control.
Field: Economizer Upper Enthalpy Limit[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for economizer operation. If the outdoor air enthalpy is above this value, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air enthalpy limit control.
Field: Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC) for economizer operation. If the outdoor air dewpoint temperature is above this value, the outdoor airflow rate will be set to the minimum. This field is required if the Economizer Control Type ‘FixedDewPointAndDryBulb’ has been specified. No input (blank) in this field means that there is no outdoor air dewpoint limit control.
Field: Supply Plenum Name[LINK]
Set to blank if no supply plenum is to be modeled. If a supply plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This supply plenum serves all zones on this system. If any AirLoopHVAC:SupplyPlenums have been specified, the outlet from the system supply plenum will flow through the [AirLoopHVAC:SupplyPlenum](../input-output-reference/page-038.html#airloophvacsupplyplenum) to the zone terminal unit.
Field: Return Plenum Name[LINK]
Set to blank if no return plenum is to be modeled. If a return plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This return plenum serves all zones on this system. If any zone return plenums have been specified, the return air from the zone will flow through the zone return plenum and then into the system return plenum.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the cooling and heating coils. BlowThrough models a system where the supply air fan is before the cooling and heating coils. The default is Draw Through.
Field: Supply Fan Part-Load Power Coefficients[LINK]
Select the set of generic pre-defined coefficients to use for the supply fan part-load power consumption. This alpha field has the following choices:
The default is InletVaneDampers. The resulting power curves are shown in Figure 146. VAV Supply Fan Part-Load Power Coefficient Options below. The ASHRAE 90.1-2004 Appendix G coefficients are from TABLE G3.1.3.15, Method 2. The other sets of coefficients are from the EnergyPlus Input Output Reference, Fan Coefficient Values table. The VariableSpeedMotorPressureReset option is based on Good Static Pressure Reset VSD Fan from Energy Design Resources’: Design Guidelines: Advanced Variable Air Volume (VAV) Systems (EDR_DesignGuidelines_VAV.pdf).
Field: Night Cycle Control[LINK]
Enter the system behavior during times when the System Availability Schedule is zero (off). The possible inputs are StayOff, CycleOnAny, CycleOnControl Zone](page-011.html#zone) or CycleOnAnyZoneFansOnly. StayOff means the system will remain off, no matter how hot or cold the zones may be. CycleOnAny means that if any zone served by this system has an air temperature outside the cooling or heating set points the central fan will turn on even though the System Availability Schedule indicates the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone) means the same thing except the availability manager looks at the temperature in only the zone specified in Night Cycle Control [Zone](../input-output-reference/page-011.html#zone) Name. CycleOnAnyZoneFansOnly is the same as CycleOnAny except that only the zone fans are cycled on and the central air handler fan is left off (applicable only if using [HVACTemplate:Zone:VAV:FanPowered in one or more zones). The default is StayOff.
Field: Night Cycle Control Zone Name[LINK]
For the Night Cycle Control option Cycle On Control Zone enter the name of the control zone. For other Night Cycle Control options, this field is ignored.
Field: Heat Recovery Type[LINK]
Enter the type of air-to-air heat recovery which is available between the relief air stream and the outdoor air inlet stream. The choices are:
The default is None. If heat recovery is specified (i.e., Sensible or Enthalpy), then a value must be entered in the Minimum Outdoor Air Flow Rate field, because heat recovery equipment is not yet autosizable. The entered Minimum Outdoor Air Flow Rate is used to define the Nominal Supply Air Flow Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent) object generated by this template.
Field: Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.70.
Field: Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat Recovery Type is Enthalpy. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.65.
Field: Cooling Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the cooling supply air temperature. The choices are:
The default is None.
Field: Heating Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the central heating supply air temperature. The choices are:
The default is None.
Field: Dehumidification Control Type[LINK]
There are two dehumidification control type options available:
The CoolReheat option cools beyond the dry-bulb setpoint as required to meet the humidity setpoint if the system is capable of doing so. Reheat is provided as required by the terminal unit reheat coils if available.
The default is None which meets the sensible cooling setpoint only.
Field: Dehumidification Control Zone Name[LINK]
This field specifies the zone name where the humidistat is located for controlling dehumidification.
Field: Dehumidification Setpoint[LINK]
This field specifies the zone humidistat setpoint for dehumidification in percent (0 to 100). The default is 60%.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric) object. The default is None.
Field: Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the system is operating. If a schedule name is specified, it defines when the humidifier is available. The schedule values denote whether the humidifier can run during a given time period. A schedule value of 1.0 indicates that the humidifier can be on during a given time period. A value of zero denotes that the humidifier cannot be used during that time period
Field: Humidifier Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The humidifier does not currently autosize, so the default is very large to allow for adequate capacity. The default is 0.000001 m3/s.
Field: Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity moisture output. This field can be autosized. When it is autosized, it is calculated from the rated capacity in kg/s and the enthalpy rise in J/kg of the feed water from a reference temperature of liquid water at 20°C to saturated steam at 100°C.
Field: Humidifier Control Zone Name[LINK]
This field specifies the zone name where the humidistat is located for controlling humidification.
Field: Humidifier Setpoint[LINK]
This field specifies the zone humidistat setpoint for humidification in percent (0 to 100). The default is 30%.
Field: Sizing Option[LINK]
This field specifies the sizing method for the system supply air flow rate. Coincident sizes on the sum of the coincident zone supply air flow rates. NonCoincident sizes on sum of the noncoincident zone design supply air flow rates. The default is NonCoincident.
As shown in an IDF:
HVACTemplate:System:PackagedVAV[LINK]
This object simulates the system portion of a packaged direct-expansion based variable air volume HVAC configuration with several different heating options. Multiple HVACTemplate:Zone:VAV objects are usually specified for each HVACTemplate:System:PackagedVAV object.
Field: Name[LINK]
Enter a name for the HVACTemplate:System:PackagedVAV object. This name is used in the HVACTemplate:Zone:VAV object to reference this system.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to be available for the entire year to perform heating or cooling if called for by the thermostat. If a schedule name is specified, those times that the system is available should be specified as 1.0. Those times that the system is not available should have a zero value in the schedule specified. Please note that for this system type, this is a schedule of when the system is providing air flow.
Field: Supply Fan Maximum Flow Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to the sum of the zone air flow rates. If a value is entered here for the maximum air-flow rate, it is the upper limit on system flow, even if the zone level air flow inputs sum to a greater value. This flow rate will not be multiplied by a sizing factor or by zone multipliers. If using zone multipliers a value entered here must be large enough to serve the multiplied zones. The units are m3/s. The default is Autosize.
Field: Supply Fan Minimum Flow Rate[LINK]
Enter the minimum supply air volume that may be provided. This field may be set to autosize. The units are in m3/s.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the cooling and heating coils. BlowThrough models a system where the supply air fan is before the cooling and heating coils. The default is DrawThrough.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1. The default is 0.7.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered 20oC at sea level, 101325 Pa. The default is 1000 Pa.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater or equal to the Supply Fan Total Efficiency and less than or equal to 1. The default is 0.9.
Field: Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat will go into the air stream and act to cause a temperature rise. Must be between 0 and 1. The default is 1.0.
Field: Cooling Coil Type[LINK]
The coil types available:
TwoSpeedDX uses the [Coil:Cooling:DX:TwoSpeed](../input-output-reference/page-042.html#coilcoolingdxtwospeed) object. This is the preferred coil model for most applications. The TwoSpeedHumidControlDX option uses the [Coil:Cooling:DX:TwoStageWithHumidityControlMode](../input-output-reference/page-042.html#coilcoolingdxtwostagewithhumiditycontrolmode) object.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the cooling coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when cooling is only available seasonally. A schedule value of one indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the cooling coil is to be specified, leave this field blank, and the Cooling Coil Design Setpoint value will be used at all times. If a set point schedule is to be used for the cooling coil specify the schedule name here. The schedule should control the supply air temperature delivered to the zones. For Blow Through fan placement, this is the leaving air temperature from the cooling coil. For Draw Through fan placement, this is the leaving air temperature after the supply fan. The values in the schedule are in degrees C. This field is ignored if the Cooling Coil Setpoint Reset Type is something other than None (see below). The default is None.
Field: Cooling Coil Design Setpoint[LINK]
Enter the cooling supply air temperature in degrees C to be used for sizing the cooling coil and zone supply air flow rates. The default is 12.8C. If no Cooling Coil Setpoint Schedule or Cooling Coil Setpoint Reset Type is specified, this value is used as a constant cooling supply air setpoint temperature.
Field: Cooling Coil Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm determine the cooling coil capacity based on the maximum cooling loads during the cooling design day. If a value is entered, it represents the full load cooling capacity, including both sensible and latent capacity, in watts of the DX coil unit at rated conditions. For Cooling Coil Type = TwoSpeedDX, the low-speed capacity is assumed to be 0.33 times this value. For Cooling Coil Type = TwoSpeedHumidControlDX, the stage 1 capacity is assumed to be 0.5 times this value. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is Autosize.
Field: Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine the sensible heat ratio based on the rated capacity and air flow rate. Otherwise, enter the value of the ratio of the sensible capacity divided by total cooling capacity of the DX cooling coil at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. Both the sensible and total cooling capacities used to define the Rated Sensible Heat Ratio (SHR) should be “gross” capacity where the impact of supply air fan heat is NOT included. The default is Autosize.
Field: Cooling Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross cooling coil capacity in watts divided by electrical power input in watts of the DX cooling coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor condenser coil at 35°C drybulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 3.0.
Field: Heating Coil Type[LINK]
Enter the type of heating used in the unitary system. The choices for this field are
Field: Heating Coil Availability Schedule Name[LINK]
Usually set to blank, which allows the heating coil to be available anytime the system is operating. If a schedule name is specified, it defines when the coil is available. This is most often used when heating is only available seasonally. The schedule values denote whether the heating coil can run during a given time period. A schedule value of 1.0 indicates that the heating coil can be on during a given time period. A value of zero denotes that the heating coil cannot be used during that time period
Field: Heating Coil Setpoint Schedule Name[LINK]
If a constant setpoint for the heating coil is to be specified, leave this field blank, and the Heating Coil Design Setpoint value will be used at all times. If a set point schedule is to be used for the heating coil specify the schedule name here. The schedule should control the supply air temperature delivered to the zones. For Blow Through fan placement, this is the leaving air temperature from the heating coil. For Draw Through fan placement, this is the leaving air temperature after the supply fan. The values in the schedule are in degrees C. This field is ignored if the Heating Coil Setpoint Reset Type is something other than None (see below).
Field: Heating Coil Design Setpoint[LINK]
Enter the heating supply air temperature in degrees C to be used for sizing the heating coil and zone supply air flow rates. If no Heating Coil Setpoint Schedule or Heating Coil Setpoint Reset Type is specified, this value is used as a constant heating supply air setpoint temperature. The default is 10.0C.
Field: Heating Coil Capacity[LINK]
Enter Autosize to allow the sizing algorithm to determine the proper capacity required based on the loads experienced during the heating design day. If a value is specified, it is the maximum amount of heat that the coil can deliver in Watts.
Field: Gas Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default
Field: Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas heating coil operation, such as a combustion fan. The units are in W. The default is 0.0 W.
Field: Maximum Outdoor Air Flow Rate[LINK]
Enter Autosize or a value for the maximum amount of outdoor air flow into the unit when the economizer is operating. Autosize means that 100% of the full supply flow may be taken from outdoor air. If a value is entered, it is used instead of the autosize value. The units are in m3/s. That is, the entered value is used to define the Maximum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template. The default is Autosize.
Field: Minimum Outdoor Air Flow Rate[LINK]
Enter Autosize or the value for the minimum amount of outdoor air that can enter the unit and be distributed to the zones. Usually this is set to autosize and the value is calculated by the outdoor air requirements of each zone. If a value is entered it overrides the outdoor air specification from the zone level. The units are in m3/s. The default is Autosize. Note if heat recovery is specified (see Heat Recovery Type below), then a value must be entered in this field, because heat recovery equipment is not yet autosizable. That is, the entered value is used to define the Minimum Outdoor Air Flow Rate for the [Controller:OutdoorAir](../input-output-reference/page-051.html#controlleroutdoorair) object that will be generated by this template.
Field: Minimum Outdoor Air Control Type[LINK]
Choices for this field are FixedMinimum or ProportionalMinimum. FixedMinimum means that the minimum outdoor air flow rate is fixed no matter what the actual system flow rate is. ProportionalMinimum means the minimum outdoor air flow rate varies in proportion to the total system air flow rate. The default is ProportionalMinimum.
Field: Minimum Outdoor Air Schedule Name[LINK]
Leave this field blank if you want the minimum outdoor air to be the same for all hours in the entire year. If a schedule name is specified, values are decimal fractions (0.0 – 1.0) that multiply the minimum outdoor air flow rate. This schedule is useful for reducing the outdoor air flow rate to zero during unoccupied or start up hours.
Field: Economizer Type[LINK]
The options for this field are
Choosing NoEconomizer means the economizer will not operate and the outdoor airflow rate will be at the minimum for the entire simulation.
Choosing FixedDryBulb means the economizer will set the outdoor airflow rate at minimum if the outdoor air temperature is higher than a specified dry-bulb temperature limit.
Choosing DifferentialDryBulb will trigger the outdoor airflow to minimum when the dry-bulb temperature of outdoor air is higher than the dry-bulb temperature of the return air.
FixedEnthalpy checks the upper limit of the enthalpy given as a field input against the enthalpy content of outdoor air and will set the outdoor airflow rate to minimum if the latter is greater than the former.
DifferentialEnthalpy does the same thing but compares the return air enthalpy with the enthalpy of outdoor air. When the enthalpy of outdoor air is greater than the enthalpy of the return air, the outdoor air flow rate is set to minimum.
Choosing ElectronicEnthalpy enables the simulation to calculate the humidity ratio limit of outdoor air based on the dry-bulb temperature of outdoor air and a quadratic/cubic curve, and compare it to the actual outdoor air humidity ratio. If the actual outdoor humidity ratio is greater than the calculated humidity ratio limit, then the outdoor airflow rate is set to minimum.
Choosing FixedDewPointAndDryBulb compares both the outdoor dewpoint temperature and the outdoor dry-bulb temperature to their specified high limit values. If either outdoor temperature exceeds the high limit value, the outdoor airflow rate is set to minimum.
Another option DifferentialDryBulbAndEnthalpy enables the control strategy to be based on both the DifferentialDryBulb and DifferentialEnthalpy economizer control strategies.
In addition to all economizer control types listed above, each control type checks for user-entered values for the upper limit of dry-bulb temperature, enthalpy limit, humidity ratio limit and dewpoint limit. The outdoor air flow rate is set to minimum if any of these entered limits are exceeded.
The default for this field is NoEconomizer.
Field: Economizer Lockout[LINK]
Enter one of the following choices for this field:
The default value is NoLockout. The LockoutWithHeating means that if the packaged unit is in heating mode, the economizer is locked out – i.e., the economizer dampers are closed and there is minimum outdoor air flow. LockoutWithCompressor means that in addition to locking out the economizer when the unit is in heating mode the economizer is locked out when the DX unit compressor is on. In other words, when the DX coil is off, the economizer must meet the entire cooling load – it isn’t allowed to operate in conjunction with the DX cooling coil. Similarly, when the DX coil is operating, the economizer is not allowed to operate. The LockoutWithCompressor option is sometimes called a “nonintegrated” economizer.
Field: Economizer Maximum Limit Dry-Bulb Temperature[LINK]
Input for this field is the outdoor air temperature high limit (ºC) for economizer operation. If the outdoor air temperature is above this limit, the outdoor airflow rate will be set to the minimum. This field is required if Economizer Control Type ‘FixedDryBulb’ or ‘FixedDewPointAndDryBulb’ has been specified. No input (blank) in this field means that there is no outdoor air temperature high limit control.
Field: Economizer Maximum Limit Enthalpy[LINK]
Enter the outdoor air upper enthalpy limit (in J/kg) for economizer operation. If the outdoor air enthalpy is above this value, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air enthalpy limit control.
Field: Economizer Maximum Limit Dewpoint Temperature[LINK]
Input for this field is the outdoor air dewpoint limit (ºC) for economizer operation. If the outdoor air dewpoint temperature is above this value, the outdoor airflow rate will be set to the minimum. This field is required if the Economizer Control Type ‘FixedDewPointAndDryBulb’ has been specified. No input (blank) in this field means that there is no outdoor air dewpoint limit control.
Field: Economizer Minimum Limit Dry-Bulb Temperature[LINK]
Enter the outdoor air temperature low limit (C) for economizer operation. If the outdoor air temperature is below this limit, the outdoor air flow rate will be set to the minimum and heat recovery will be enabled if available. No input or zero in this field means that there is no outdoor air temperature low limit control.
Field: Supply Plenum Name[LINK]
Set to blank if no supply plenum is to be modeled. If a supply plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This supply plenum serves all zones on this system. If any zone supply plenums have been specified, the outlet from the system supply plenum will flow through the zone supply plenum to the zone terminal unit.
Field: Return Plenum Name[LINK]
Set to blank if no return plenum is to be modeled. If a return plenum is modeled, it must be modeled as a zone with surfaces, and the name of the plenum zone should be entered here. This return plenum serves all zones on this system. If any zone return plenums have been specified, the return air from the zone will flow through the zone return plenum and then into the system return plenum.
Field: Supply Fan Part-Load Power Coefficients[LINK]
Select the set of generic pre-defined coefficients to use for the supply fan part-load power consumption. This alpha field has the following choices:
The default is InletVaneDampers. The resulting power curves are shown in Figure 147 below. The ASHRAE 90.1-2004 Appendix G coefficients are from TABLE G3.1.3.15, Method 2. The other sets of coefficients are from the EnergyPlus Input Output Reference, Fan Coefficient Values table. The VariableSpeedMotorPressureReset option is based on Good Static Pressure Reset VSD Fan from Energy Design Resources’: Design Guidelines: Advanced Variable Air Volume (VAV) Systems (EDR_DesignGuidelines_VAV.pdf).
Field: Night Cycle Control[LINK]
Enter the system behavior during times when the System Availability Schedule is zero (off). The possible inputs are StayOff, CycleOnAny, CycleOnControl Zone](page-011.html#zone) or CycleOnAnyZoneFansOnly. StayOff means the system will remain off, no matter how hot or cold the zones may be. CycleOnAny means that if any zone served by this system has an air temperature outside the cooling or heating set points the central fan will turn on even though the System Availability Schedule indicates the fan is off. CycleOnControl[Zone](../input-output-reference/page-011.html#zone) means the same thing except the availability manager looks at the temperature in only the zone specified in Night Cycle Control [Zone](../input-output-reference/page-011.html#zone) Name. CycleOnAnyZoneFansOnly is the same as CycleOnAny except that only the zone fans are cycled on and the central air handler fan is left off (applicable only if using [HVACTemplate:Zone:VAV:FanPowered in one or more zones). The default is StayOff.
Field: Night Cycle Control Zone Name[LINK]
For the Night Cycle Control option Cycle On Control Zone enter the name of the control zone. For other Night Cycle Control options, this field is ignored.
Field: Heat Recovery Type[LINK]
Enter the type of air-to-air heat recovery which is available between the relief air stream and the outdoor air inlet stream. The choices are:
The default is None. If heat recovery is specified (i.e., Sensible or Enthalpy), then a value must be entered in the Minimum Outdoor Air Flow Rate field, because heat recovery equipment is not yet autosizable. The entered Minimum Outdoor Air Flow Rate is used to define the Nominal Supply Air Flow Rate for the [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent) object generated by this template.
Field: Sensible Heat Recovery Effectiveness[LINK]
Enter the sensible heat recovery effectiveness. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.70.
Field: Latent Heat Recovery Effectiveness[LINK]
Enter the latent heat recovery effectiveness if Heat Recovery Type is Enthalpy. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.65.
Field: Cooling Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the cooling supply air temperature. The choices are:
The default is None.
Field: Heating Coil Setpoint Reset Type[LINK]
Select the type of automatic reset control for the central heating supply air temperature. The choices are:
The default is None.
Field: Dehumidification Control Type[LINK]
There are two dehumidification control type options available:
The CoolReheat option cools beyond the dry-bulb setpoint as required to meet the humidity setpoint if the system is capable of doing so. Reheat is provided as required by the terminal unit reheat coils if available.
The default is None which meets the sensible cooling setpoint only.
Field: Dehumidification Control Zone Name[LINK]
This field specifies the zone name where the humidistat is located for controlling dehumidification.
Field: Dehumidification Setpoint[LINK]
This field specifies the zone humidistat setpoint for dehumidification in percent (0 to 100). The default is 60%.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric) object. The default is None.
Field: Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the system is operating. If a schedule name is specified, it defines when the humidifier is available. The schedule values denote whether the humidifier can run during a given time period. A schedule value of 1.0 indicates that the humidifier can be on during a given time period. A value of zero denotes that the humidifier cannot be used during that time period
Field: Humidifier Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The humidifier does not currently autosize, so the default is very large to allow for adequate capacity. The default is 0.000001 m3/s.
Field: Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity moisture output. This field can be autosized. When it is autosized, it is calculated from the rated capacity in kg/s and the enthalpy rise in J/kg of the feed water from a reference temperature of liquid water at 20°C to saturated steam at 100°C.
Field: Humidifier Control Zone Name[LINK]
This field specifies the zone name where the humidistat is located for controlling humidification.
Field: Humidifier Setpoint[LINK]
This field specifies the zone humidistat setpoint for humidification in percent (0 to 100). The default is 30%.
Field: Sizing Option[LINK]
This field specifies the sizing method for the system supply air flow rate. Coincident sizes on the sum of the coincident zone supply air flow rates. NonCoincident sizes on sum of the noncoincident zone design supply air flow rates. The default is NonCoincident.
As shown in an IDF:
HVACTemplate:System:DedicatedOutdoorAir[LINK]
The HVACTemplate:System:DedicatedOutdoorAir creates a dedicated outdoor air system which must be used in conjunction with one or more of the following objects:
HVACTemplate:Zone:FanCoil
HVACTemplate:Zone:PTAC
HVACTemplate:Zone:PTHP
HVACTemplate:Zone:WaterToAirHeatPump
It is a constant volume dedicated outdoor air system which can serve multiple zones. It may have any combination of heating coil, cooling coil, and heat recovery. It may have dehumidification and humidification controls as well as several supply temperature control types. It supplies 100% outdoor air when the system is available, and assumes an equal volume of return air is available for heat recovery. If the system to be modeled does not have actual return ducts, but collects flow from exhaust fans to a central heat recovery point, then this approach should be equivalent. If the system does not have heat recovery and the air is exhausted or leaves by exfiltration, then the return path of this system will simply be a path to dump the flow as relief air with no impact on energy use.
There may be more than one HVACTemplate:System:DedicatedOutdoorAir object in an idf file. If a zone is to be served by one of these systems, this is specified in the HVACTemplate:Zone:* object using the field “Dedicated Outdoor Air System Name”. For zones which are served by one of these DOAS systems, the outdoor air flow rate in the zone equipment (fan coil, PTAC, etc.) will be set to zero.
Field: Name[LINK]
This field is a unique name which the user assigns to this system. This name can then be referred to in an HVACTemplate:Zone:* object to specify that this system provides outdoor air to that zone.
Field: System Availability Schedule Name[LINK]
Leave this field blank if you want the system to operate at all times. If a schedule name is specified, those times that the system is operating should be specified as 1.0. Those times that the system is not operating should have a zero value in the schedule specified. Please note that for this system type, this is a schedule of when the system is providing air flow.
Field: Air Outlet Type[LINK]
This field indicates if the air is delivered directly into the zone(s) or into the other system(s) that serve the zone(s) (e.g. fan coil system). For now, only one option is available for this field: DirectIntoZone.
Field: Supply Fan Flow Rate[LINK]
Enter Autosize to set the system maximum air-flow rate to the sum of the zone air flow rates. If a value is entered here for the maximum air-flow rate, it is the upper limit on system flow, even if the zone air flow inputs sum to a greater value. The units are m3/s.
Field: Supply Fan Total Efficiency[LINK]
Enter the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Delta Pressure[LINK]
Enter the pressure rise in Pa at full flow and standard conditions. Standard conditions are considered to be 20oC at sea level, 101325 Pa.
Field: Supply Fan Motor Efficiency[LINK]
Enter the shaft power of the supply fan divided by the electrical power consumed. Must be greater than 0 and less than or equal to 1.
Field: Supply Fan Motor in Air Stream Fraction[LINK]
Enter the fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat will go into the air stream and act to cause a temperature rise. Must be between 0 and 1.
Field: Supply Fan Placement[LINK]
Enter the supply fan placement type. This alpha field has two choices, DrawThrough or BlowThrough. DrawThrough models a system where the supply air fan is after the cooling and heating coils. BlowThrough models a system where the supply air fan is before the cooling and heating coils. The default is DrawThrough.
Field: Cooling Coil Type[LINK]
There are seven coil types available:
ChilledWater uses the [Coil:Cooling:Water](../input-output-reference/page-042.html#coilcoolingwater) object with the DetailedAnalysis option. This is the preferred coil model for most chilled water applications.
ChilledWaterDetailedFlatModel uses the [Coil:Cooling:Water:DetailedGeometry](../input-output-reference/page-042.html#coilcoolingwaterdetailedgeometry) object. This option is available for special applications.
TwoSpeedDX uses the [Coil:Cooling:DX:TwoSpeed](../input-output-reference/page-042.html#coilcoolingdxtwospeed) object.
TwoStageDX and TwoStageHumidityControlDX use the [Coil:Cooling:DX:TwoStageWithHumidityControlMode](../input-output-reference/page-042.html#coilcoolingdxtwostagewithhumiditycontrolmode) object.
HeatExchangerAssistedChilledWater uses the [CoilSystem:Cooling:Water:HeatExchangerAssisted](../input-output-reference/page-042.html#coilsystemcoolingwaterheatexchangerassisted), [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent), and [Coil:Cooling:Water](../input-output-reference/page-042.html#coilcoolingwater) objects.
HeatExchangerAssistedDX uses the [CoilSystem:Cooling:DX:HeatExchangerAssisted](../input-output-reference/page-042.html#coilsystemcoolingdxheatexchangerassisted), [HeatExchanger:AirToAir:SensibleAndLatent](../input-output-reference/page-053.html#heatexchangerairtoairsensibleandlatent), and [Coil:Cooling:DX:SingleSpeed](../input-output-reference/page-042.html#coilcoolingdxsinglespeed) objects.
The default type is ChilledWater.
Field: Cooling Coil Availability Schedule Name[LINK]
Usually left blank, which allows the cooling coil to be available as needed anytime the system is operating. If a schedule name is specified, it defines when the cooling coil is available. This is most often used when cooling is only available seasonally. A schedule value of one indicates that the cooling coil can be on during a given time period. A value of zero denotes that the cooling coil cannot be used during that time period.
Field: Cooling Coil Setpoint Control Type[LINK]
Specifies the cooling coil setpoint control type:
FixedSetpoint uses the Cooling Coil Design Setpoint as the supply air setpoint. Scheduled uses the Cooling Coil Setpoint Schedule to set the supply air setpoint. OutdoorAirTemperatureReset varies the supply air setpoint based on the values entered for Cooling Coil Setpoint at Outdoor Dry-Bulb Low, Cooling Coil Reset Outdoor Dry-Bulb Low, Cooling Coil Setpoint at Outdoor Dry-Bulb High, and Cooling Coil Reset Outdoor Dry-Bulb High. The default is FixedSetpoint.
Field: Cooling Coil Design Setpoint[LINK]
Enter the cooling supply air temperature in C to be used for sizing the cooling coil and zone supply air flow rates. The default is 12.8C. If Cooling Coil Setpoint Control Type = FixedSetpoint, then this value is also used as the constant cooling supply air setpoint temperature.
Field: Cooling Coil Setpoint Schedule Name[LINK]
This field is used when Cooling Coil Setpoint Control Type = Scheduled. The schedule should control the supply air temperature delivered to the zones. For Blow Through fan placement, this is the leaving air temperature from the cooling coil. For Draw Through fan placement, this is the leaving air temperature after the supply fan. The values in the schedule are in degrees C. This field is ignored if the Cooling Coil Setpoint Reset Type is something other than Scheduled (see above).
Field: Cooling Coil Setpoint at Outdoor Dry-Bulb Low[LINK]
The cooling coil supply air setpoint temperature in C when the outdoor dry-bulb temperature is at or below the low limit (Cooling Coil Reset Outdoor Dry-Bulb Low). Used only when Cooling Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 15.6C.
Field: Cooling Coil Reset Outdoor Dry-Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or below this temperature, the setpoint is the value of Cooling Coil Setpoint at Outdoor Dry-Bulb Low. Used only when Cooling Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 15.6C.
Field: Cooling Coil Setpoint at Outdoor Dry-Bulb High[LINK]
The cooling coil supply air setpoint temperature in C when the outdoor dry-bulb temperature is at or above the high limit (Cooling Coil Reset Outdoor Dry-Bulb High). Used only when Cooling Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 12.8C.
Field: Cooling Coil Reset Outdoor Dry-Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or above this temperature, the setpoint is the value of Cooling Coil Setpoint at Outdoor Dry-Bulb High. Used only when Cooling Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 23.3C.
Field: DX Cooling Coil Capacity[LINK]
Enter Autosize to let the automatic sizing algorithm determine the cooling coil capacity based on the maximum cooling loads during the cooling design day. If a value is entered, it represents the full load cooling capacity, including both sensible and latent capacity, in watts of the DX coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor air-cooled condenser coil at 35°C drybulb. Capacity should be the “gross” capacity where the impact of supply air fan heat is NOT included. The units are in W. The default is Autosize. This field is only used when the cooling coil type is set to one of the DX options. For two-speed DX coils, the low-speed capacity is assumed to be 0.33 times this value. For two-stage DX coils, the stage 1 capacity is assumed to be 0.5 times this value.
Field: DX Cooling Coil Rated Sensible Heat Ratio[LINK]
Enter Autosize to allow the sizing algorithm to determine the sensible heat ratio based on the rated capacity and air flow rate. Otherwise, enter the value of the ratio of the sensible capacity divided by total cooling capacity of the DX cooling coil at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor air-cooled condenser coil at 35°C drybulb. Both the sensible and total cooling capacities used to define the Rated Sensible Heat Ratio (SHR) should be “gross” capacity where the impact of supply air fan heat is NOT included. The default is Autosize. This field is only used when the cooling coil type is set to one of the DX options. For two-speed DX coils, the low-speed SHR is assumed to be equal to this value. For two-stage DX coils, the stage 1 SHR is assumed to be equal to this value. For two-stage DX coil with humidity control, the humidity control mode SHR is assumed to be 0.9 times this value (for both stage 1 and stage 2).
Field: DX Cooling Coil Rated COP[LINK]
Enter the coefficient of performance defined as the gross cooling coil capacity in watts divided by electrical power input in watts of the DX cooling coil unit at rated conditions. Rated conditions are air entering the cooling coil at the maximum supply air flow rate at 26.7°C drybulb/19.4°C wetbulb with air entering the outdoor air-cooled condenser coil at 35°C drybulb. The input power includes electric power for the compressor and condenser fan but does not include the power consumption of the supply air fan. The default is 3.0. This field is only used when the cooling coil type is set to one of the DX options. For two-speed DX coils, the low-speed COP is assumed to be 1.5 times this value. For two-stage DX coils, the stage 1 COP is assumed to be this this value. For two-stage DX coil with humidity control, the humidity control mode COP is assumed to be 0.9 times this value (for both stage 1 and stage 2).
Field: Heating Coil Type[LINK]
The heating coil is located in the supply air stream, downstream of the cooling coil. If no central heating coil is used in the dedicated outdoor air system, then the option “none” should be specified here. Otherwise this indicates the type of heating coil. The choices for this field are
The default value is HotWater. If a heating coil is specified, the heating and cooling coil setpoint controls and availability schedules must coordinate to prevent the coils from opposing each other. When the dehumidification control type is set to CoolReheatHeatingCoil, the heating coil is used for reheat.
Field: Heating Coil Availability Schedule Name[LINK]
Usually left blank, which allows the heating coil to be available as needed anytime the system is operating. If a schedule name is specified, it defines when the heating coil is available. This is most often used when heating is only available seasonally. The schedule values denote whether the heating coil can run during a given time period. A schedule value of one indicates that the heating coil can be on during a given time period. A value of zero denotes that the heating coil cannot be used during that time period.
Field: Heating Coil Setpoint Control Type[LINK]
Specifies the cooling coil setpoint control type:
FixedSetpoint uses the Heating Coil Design Setpoint as the supply air setpoint. Scheduled uses the Heating Coil Setpoint Schedule to set the supply air setpoint. OutdoorAirTemperatureReset varies the supply air setpoint based on the values entered for Heating Coil Setpoint at Outdoor Dry-Bulb Low, Heating Coil Reset Outdoor Dry-Bulb Low, Heating Coil Setpoint at Outdoor Dry-Bulb High, and Heating Coil Reset Outdoor Dry-Bulb High. The default is FixedSetpoint.
Field: Heating Coil Design Setpoint[LINK]
Enter the heating supply air temperature in C to be used for sizing the heating coil and zone supply air flow rates. If Heating Coil Setpoint Control Type = FixedSetpoint, then this value is also used as the constant heating supply air setpoint temperature. The default is 12.2C.
Field: Heating Coil Setpoint Schedule Name[LINK]
This field is used when Heating Coil Setpoint Control Type = Scheduled. The schedule should control the supply air temperature delivered to the zones. For Blow Through fan placement, this is the leaving air temperature from the heating coil. For Draw Through fan placement, this is the leaving air temperature after the supply fan. The values in the schedule are in degrees C.
Field: Heating Coil Setpoint at Outdoor Dry-Bulb Low[LINK]
The heating coil supply air setpoint temperature in C when the outdoor dry-bulb temperature is at or below the low limit (Heating Coil Reset Outdoor Dry-Bulb Low). Used only when Heating Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 15.0C.
Field: Heating Coil Reset Outdoor Dry-Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or below this temperature, the setpoint is the value of Heating Coil Setpoint at Outdoor Dry-Bulb Low. Used only when Heating Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 7.8C.
Field: Heating Coil Setpoint at Outdoor Dry-Bulb High[LINK]
The heating coil supply air setpoint temperature in C when the outdoor dry-bulb temperature is at or above the high limit (Heating Coil Reset Outdoor Dry-Bulb High). Used only when Heating Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 12.2C.
Field: Heating Coil Reset Outdoor Dry-Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or above this temperature, the setpoint is the value of Heating Coil Setpoint at Outdoor Dry-Bulb High. Used only when Heating Coil Setpoint Control Type = OutdoorAirTemperatureReset. The default is 12.2C.
Field: Gas Heating Coil Efficiency[LINK]
Enter gas burner efficiency as a decimal, not as a percent. A burner that is 80% efficient would have an entry of 0.8 here, which is the default. This field is only used when the heating coil type is set to gas.
Field: Gas Heating Coil Parasitic Electric Load[LINK]
Enter the parasitic electric load associated with the gas heating coil operation, such as a combustion fan. The units are in W. This field is only used when the heating coil type is set to gas.
Field: Heat Recovery Type[LINK]
Enter the type of air-to-air heat recovery which is available between the relief air stream and the outdoor air inlet stream. The choices are:
The default is None.
Field: Heat Recovery Sensible Effectiveness [][LINK]
Enter the sensible heat recovery effectiveness. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.70.
Field: Heat Recovery Latent Effectiveness [][LINK]
Enter the latent heat recovery effectiveness if Heat Recovery Type is Enthalpy. This is applied as a constant effectiveness at all conditions. The valid range is from 0.0 to 1.0, and the default is 0.65.
Field: Heat Recovery Heat Exchanger Type[LINK]
This alpha field denotes the type of heat exchanger being modeled: Plate (e.g., fixed plate) or Rotary (e.g., rotating cylinder or wheel). The default choice for this field is “Plate”. The heat exchanger type affects the modeling of frost control options and supply air outlet temperature control. For rotary heat exchangers, rotational speed is varied to control frost formation or the supply air outlet temperature. For plate exchangers, air bypass around the heat exchanger is used to obtain the desired effect.
Field: Heat Recovery Frost Control Type[LINK]
This alpha field has four choices: None, ExhaustAirRecirculation, ExhaustOnly and MinimumExhaustTemperature. If this field is left blank, the default frost control type is “None”. For modeling preheat frost control, specify “None” for this input field and insert a separate heating coil object in the supply inlet air stream to keep the air temperature above the desired frost threshold temperature.
ExhaustAirRecirculation: dampers are used to direct exhaust air back into the zone through the supply side of the heat exchanger when the supply (outdoor) air inlet temperature falls below a threshold temperature. The fraction of time that exhaust air is circulated through the supply side of the heat exchanger is dependent on the supply (outdoor) air inlet temperature with respect to the threshold temperature, the initial defrost time fraction, and the rate of change of defrost time. When exhaust air is being recirculated, no supply (outdoor ventilation) air is being provided through the heat exchanger unit (which may or may not be acceptable regarding ventilation for occupants).
ExhaustOnly (supply air bypass): this control cycles off the supply air flow through the heat exchanger for a certain period of time while the exhaust air continues to flow through the exhaust side of the heat exchanger. The fraction of time that the supply flow through the heat exchanger is cycled off is dependent on the supply (outdoor) air inlet temperature with respect to the threshold temperature, the initial defrost time fraction, and the rate of change of defrost time. When implemented in real applications, provisions are usually made to avoid building depressurization when this frost control is operating (automatic or pressure-operated dampers, or a bypass air damper around the supply side of the heat exchanger). For this frost control type, it is assumed that the supply air is bypassed around the heat exchanger during frost control operation (i.e., the total supply flow is not reduced during defrost, but merely bypassed around the heat exchanger).
MinimumExhaustTemperature: the temperature of the exhaust air leaving the heat exchanger is monitored and the heat exchanger effectiveness is decreased (by slowing heat exchanger rotation or bypassing supply air around the plate exchanger) to keep the exhaust air from falling below the threshold temperature.
Field: Dehumidification Control Type[LINK]
There are three dehumidification control type options available:
The CoolReheatHeatingCoil option cools beyond the dry-bulb setpoint as required to meet the humidity setpoint if the system is capable of doing so. Reheat is provided as required by the heating coil, if available.
The CollReheatDesuperheater option cools beyond the dry-bulb setpoint as required to meet the humidity setpoint if the system is capable of doing so. Reheat is provided by a desuperheater coil (Ref. object [Coil:Heating:Desuperheater](../input-output-reference/page-042.html#coilheatingdesuperheater)). The desuperheater coil setpoint is set to the cooling setpoint and the desuperheater Heat Reclaim Recovery Efficiency is set to 0.3. CollReheatDesuperheater is only applicable for Cooling Coil Type TwoSpeedDX, TwoStageDX, TwoStageHumidityControlDX, or HeatExchangerAssistedDX.
Multimode is only applicable for cooling coil type TwoStageHumidityControlDX. In this case, the enhanced dehumidification mode is activated as needed, but the system operates to meet the sensible dry-bulb temperature cooling setpoint.
The default is None which meets the sensible dry-bulb temperature cooling setpoint only.
Field: Dehumidification Setpoint[LINK]
This field specifies the supply air humidity ratio setpoint for dehumidification. The default is 0.00924 kgWater/kgDryAir (12.8C or 55F dewpoint). This value is also used as the Central Cooling Design Supply Air Humidity Ratio in the [Sizing:System](../input-output-reference/page-019.html#sizingsystem) object. If a Dehumidification Setpoint Schedule Name is specified, the schedule will be used for control.
Field: Humidifier Type[LINK]
There are two humidifier type options available:
The ElectricSteam humidifier option uses the [Humidifier:Steam:Electric](../input-output-reference/page-044.html#humidifiersteamelectric) object. The default is None.
Field: Humidifier Availability Schedule Name[LINK]
If left blank, the humidifier will be available anytime the system is operating. If a schedule name is specified, it defines when the humidifier is available. The schedule values denote whether the humidifier can run during a given time period. A schedule value of 1.0 indicates that the humidifier can be on during a given time period. A value of zero denotes that the humidifier cannot be used during that time period.
Field: Humidifier Rated Capacity[LINK]
Enter the rated moisture output rate in m3/s. The humidifier does not currently autosize, so the default is very large to allow for adequate capacity. The default is 0.000001 m3/s.
Field: Humidifier Rated Electric Power[LINK]
Enter the electric power input at the rated capacity moisture output. This field can be autosized. When it is autosized, it is calculated from the rated capacity in kg/s and the enthalpy rise in J/kg of the feed water from a reference temperature of liquid water at 20°C to saturated steam at 100°C.
Field: Humidifier Setpoint[LINK]
This field specifies the supply air humidity ratio setpoint for humidification. The default is 0.003 kgWater/kgDryAir. This value is also used as the Central Heating Design Supply Air Humidity Ratio in the [Sizing:System](../input-output-reference/page-019.html#sizingsystem) object. If a Humidifier Setpoint Schedule Name is specified, the schedule will be used for control.
Field: Dehumidification Setpoint Schedule Name[LINK]
Enter the name of the dehumidification setpoint schedule. If this field is left blank, the setpoint will be constant at the Dehumidification Setpoint, The values in the schedule are in units of humidity ratio (kgWater/kgDryAir or lbWater/lbDryAir).
Field: Humidifier Setpoint Schedule Name[LINK]
Enter the name of the humidifier setpoint schedule. If this field is left blank, the setpoint will be constant at the Humidifier Setpoint, The values in the schedule are in units of humidity ratio (kgWater/kgDryAir or lbWater/lbDryAir).
As shown in an IDF:
HVACTemplate:Plant:ChilledWaterLoop[LINK]
The piping systems that connect the chilled water coils in the HVAC template objects with the chillers and the cooling towers (if present) are described with this object. The piping systems are called loops and this object describes the controls and pumps on the loops. Only one of these objects may be defined in an input file and all chilled water coils from HVAC template objects are served with this object.
Field: Name[LINK]
The name used to designate the HVACTemplate:Plant:ChilledWaterLoop.
Field: Pump Schedule Name[LINK]
Leave this field blank if the chilled water and condenser water pumps are always available. If a schedule name is specified, those times that the pumps are available should be specified as 1.0. Those times that the pumps are not available should have a zero value in the schedule specified. Please note that this is not a schedule of when the system is providing chilled water to the coils but a schedule of when it can provide chilled water to the coils.
Field: Pump Control Type[LINK]
Applies to both chilled water and condenser loop pumps. The choices for this field are:
The default value is Intermittent.
If the pump control type is Continuous, the pump will run according to the Pump Schedule (see above) regardless of whether or not there is a load. If the pump control type is Intermittent, the pump will run if a load is sensed and will shut off if there is no load on the loop.
Field: Chiller Plant Operation Scheme Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all times operating in order of Priority specified in HVACTemplate:Plant:Chiller objects. If a different scheme is to be used to sequence the chillers, then this entry should be set to User Defined. If the User Defined option is chosen, then additional EnergyPlus objects must be included and completely defined in the IDF file such as shown below depending on the type of plant operation control scheme chosen:
The default value is Default.
Field: Chiller Plant Equipment Operation Schemes Name[LINK]
This field should contain the name of a [PlantEquipmentOperationSchemes](../input-output-reference/page-023.html#plantequipmentoperationschemes) object only when the previous field is set to UserDefined. It is ignored if Chiller Plant Operation Scheme Type is Default.
Field: Chilled Water Setpoint Schedule Name[LINK]
Enter the name of a chilled water setpoint schedule that has values that change at different times of the year. If a constant set point is needed simply leave this field blank and the value in the next field will be used at all times. The values in the schedule are in degrees C. This field is ignored if the Chilled Water Setpoint Reset Type is something other than None.
Field: Chilled Water Design Setpoint[LINK]
Enter the chilled water setpoint temperature to be used for sizing the chilled water loop and associated equipment in degrees C. If the Chilled Water Setpoint Schedule is blank and the Chilled Water Setpoint Reset Type is None, then this value will be used as the setpoint at all times.
Field: Chilled Water Pump Configuration[LINK]
The choices for this field are
The default value is ConstantPrimaryNoSecondary.
The operation of a constant speed pump is fairly straightforward. If the user designates a constant speed pump that is operating continuously, the pump will run regardless of whether or not there is a load. This may have the net effect of adding heat to the loop if no equipment is turned on. If the pump is constant speed and operates intermittently, the pump will run at its capacity if a load is sensed and will shut off if there is no load on the loop.
A variable speed pump is defined with maximum and minimum flow rates that are the physical limits of the device. If there is no load on the loop and the pump is operating intermittently, then the pump can shutdown. For any other condition such as the loop having a load and the pump is operating intermittently or the pump is continuously operating (regardless of the loading condition), the pump will operate and select a flow somewhere between the minimum and maximum limits. In these cases where the pump is running, it will try to meet the flow request made by demand side components.
Field: Primary Chilled Water Pump Rated Head[LINK]
The rated head of the primary chilled water pump in Pa. The default value is 179352 Pa which is equivalent to 60 feet H2O.
Field: Secondary Chilled Water Pump Rated Head[LINK]
The rated head of the secondary chilled water pump in Pa. The default value is 179352 Pa which is equivalent to 60 feet H2O. This field is applicable only if the “Chilled Water Pump Configuration” is Constant Primary Variable Secondary or Variable Primary Constant Secondary.
Field: Condenser Plant Operation Scheme Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all times operating in order of Priority specified in HVACTemplate:Plant:Tower objects. If a different scheme is to be used to sequence the towers, then this entry should be set to User Defined. May be left blank if not serving any water cooled chillers.
If User Defined option is chosen, then additional EnergyPlus objects must be included and completely defined in the IDF file such as shown below depending on the type of condenser operation control scheme chosen:
The default value is Default.
Field: Condenser Equipment Operation Schemes Name[LINK]
This field should contain the name of a [CondenserEquipmentOperationSchemes](../input-output-reference/page-023.html#condenserequipmentoperationschemes) object only when the previous field is set to UserDefined. It is ignored if Condenser Plant Operation Scheme Type is Default. May be left blank if not serving any water cooled chillers.
Field: Condenser Water Temperature Control Type[LINK]
If water cooled chillers are present the condenser water temperature control can be one of the following options:
If a specified set point is used then the towers are operated to deliver that condenser water set point. If outdoor wet-bulb is used then the condenser water temperature decreases with decreasing outdoor wet-bulb temperature. May be left blank if not serving any water cooled chillers.
Field: Condenser Water Setpoint Schedule Name[LINK]
Used when Condenser Water Temperature Control Type is set to Specified Setpoint. Ignored if Condenser Water Temperature Control Type is set to Outdoor Wet-bulb. The field may be left blank if constant setpoint temperature is used for the condenser water temperature. If may also be left blank if not serving any water cooled chillers. If specified, the schedule should contain the set point temperatures in degrees C for the condenser water loop.
Field: Condenser Water Design Setpoint[LINK]
Field: Condenser Water Pump Rated Head[LINK]
The rated head of the condenser water pumps in Pa. May be left blank if not serving any water cooled chillers. The default value is 179352 Pa which is equivalent to 60 feet H2O.
Field: Chilled Water Setpoint Reset Type[LINK]
Select the type of automatic reset control for the chilled water supply temperature. The choices are:
The default is None.
Field: Chilled Water Setpoint at Outdoor Dry-Bulb Low[LINK]
The chilled water setpoint temperature in C when the outdoor dry-bulb is at or below the low limit (Chilled Water Reset Outdoor Dry Bulb Low). The default is 12.2C.
Field: Chilled Water Reset Outdoor Dry-Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or below this temperature, the setpoint is the value of Chilled Water Setpoint at Outdoor Dry Bulb Low. The default is 15.6C.
Field: Chilled Water Setpoint at Outdoor Dry-Bulb High[LINK]
The chilled water setpoint temperature in C when the outdoor dry-bulb is at or above the high limit (Chilled Water Reset Outdoor Dry Bulb Low). The default is 6.7C.
Field: Chilled Water Reset Outdoor Dry-Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or above this temperature, the setpoint is the value of Chilled Water Setpoint at Outdoor Dry Bulb High. The default is 26.7C.
Field: Chilled Water Primary Pump Type[LINK]
Describes the type of pump configuration used for the primary portion of the chilled water loop. The options include:
Field: Chilled Water Secondary Pump Type[LINK]
Describes the type of pump configuration used for the secondary portion of the chilled water loop. The options include:
Field: Condenser Water Pump Type[LINK]
Describes the type of pump configuration used for the condenser water loop. The options include:
Field: Chilled Water Supply Side Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is present in the chilled water loop. The choices for this field are
Field: Chilled Water Demand Side Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is present in the chilled water loop. The choices for this field are
Field: Condenser Water Supply Side Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is present in the condenser water loop. The choices for this field are
Field: Condenser Water Demand Side Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is present in the condenser water loop. The choices for this field are
Field: Fluid Type[LINK]
This field determines the type of fluid used for the boiler loop. The following options are available:
Field: Loop Design Delta Temperature[LINK]
The temperature difference used in sizing the loop flow rate. The default is 6.67C.
Field: Minimum Outdoor Dry Bulb Temperature[LINK]
The minimum outdoor dry bulb temperature that the chilled water loops operate.
Field: Chilled Water Load Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to sequence equipment operation in order to meet the plant loop demand. Currently, three schemes are functional. Sequential uses each piece of equipment to its maximum part load ratio and will operate the last required piece of equipment between its minimum and maximum part load ratio in order to meet the loop demand. Optimal operates each piece of equipment at its optimal part load ratio and will operate the last component between its minimum and maximum part load ratio in order to meet the loop demand. Uniform evenly distributes the loop demand among all available components on the equipment list for a given load range.
Field: Condenser Water Load Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to sequence equipment operation in order to meet the condenser loop demand. Currently, three schemes are functional. Sequential uses each piece of equipment to its maximum part load ratio and will operate the last required piece of equipment between its minimum and maximum part load ratio in order to meet the loop demand. Optimal operates each piece of equipment at its optimal part load ratio and will operate the last component between its minimum and maximum part load ratio in order to meet the loop demand. Uniform evenly distributes the loop demand among all available components on the equipment list for a given load range.
As shown in an IDF:
HVACTemplate:Plant:Chiller[LINK]
A chiller or purchased cooling source is described with this object. To define multiple chillers, use multiple HVACTemplate:Plant:Chiller objects and use the Sizing Factor field to apportion the total capacity if autosizing.
Field: Name[LINK]
The name used to reference the HVACTemplate:Plant:Chiller object.
Field: Chiller Type[LINK]
While EnergyPlus has a variety of chiller options, the only choices currently for this field are:
The EnergyPlus equipment object types which are used are [DistrictCooling](../input-output-reference/page-024.html#districtcooling) or [Chiller:Electric:EIR](../input-output-reference/page-024.html#chillerelectriceir). These equipment type keys must be used if setting up a user-defined chiller plant operation scheme.
Field: Capacity[LINK]
This field may be set to autosize, which means that the capacity is based on the peak loads during the design days. This numeric field contains the design cooling capacity of the chiller. This capacity should be at the design temperatures and water flow rates. The units are in W.
Field: Nominal COP[LINK]
This numeric field contains the chiller’s coefficient of performance. This value should not include energy use due to pumps, evap-cooled or air-cooled condenser fans, or cooling tower fans. This Nominal COP should be at the design temperatures and water flow rates. Not applicable if Chiller Type is DistrictChilledWater.
Field: Condenser Type[LINK]
The choices for this field are
The default value is WaterCooled. If WaterCooled, then at least one HVACTemplate:Plant:Tower object should be defined. Not applicable if Chiller Type is Purchased Chilled Water.
Field: Priority[LINK]
Enter the priority number of the chiller where 1 is the highest priority, 2 is just lower, 3 is lower than 2, etc. This is used if Chiller Plant Operation Scheme Type is set to Default in HVACTemplate:Plant:ChilledWaterLoop. Equipment is operated in order of the priority number. This allows multiple chillers to be sequenced.
Field: Sizing Factor[LINK]
This optional numeric field allows the user to specify a sizing factor for this component. The sizing factor is used when the component design inputs are autosized: the autosizing calculations are performed as usual and the results are multiplied by the sizing factor. For this component the chiller object inputs that would be altered by the sizing factor are: Reference Capacity, Reference Chilled Water Flow Rate and Reference Condenser Water Flow Rate. Sizing Factor allows the user to size a component to meet part of the design load while continuing to use the autosizing feature.
Field: Minimum Part Load Ratio[LINK]
This numeric field contains the chiller’s minimum part-load ratio. The expected range is between 0 and 1. Below this part-load ratio, the compressor cycles on and off to meet the cooling load. The Minimum Part Load Ratio must be less than or equal to the Maximum Part Load Ratio. The default value is 0.0.
Field: Maximum Part Load Ratio[LINK]
This numeric field contains the chiller’s maximum part-load ratio. This value may exceed 1, but the normal range is between 0.0 and 1.0. The Maximum Part Load Ratio must be greater than or equal to the Minimum Part Load Ratio. The default value is 1.0.
Field: Optimum Part Load Ratio[LINK]
This numeric field contains the chiller’s optimum part-load ratio. This is the part-load ratio at which the chiller performs at its maximum COP. The optimum part-load ratio must be greater than or equal to the Minimum Part Load Ratio, and less than or equal to the Maximum Part Load Ratio. The default value is 1.0.
Field: Minimum Unloading Ratio[LINK]
This numeric field contains the chiller’s minimum unloading ratio. The expected range is between 0 and 1. The minimum unloading ratio is where the chiller capacity can no longer be reduced by unloading and must be false loaded to meet smaller cooling loads. A typical false loading strategy is hot-gas bypass. The minimum unloading ratio must be greater than or equal to the Minimum Part Load Ratio, and less than or equal to the Maximum Part Load Ratio. The default value is 0.25.
Field: Leaving Chilled Water Lower Temperature Limit[LINK]
This numeric field contains the lower limit for the leaving chilled water temperature in Celsius. This temperature acts as a cut off for heat transfer in the evaporator, so that the fluid doesn’t get too cold. The default value is 5˚C.
As shown in an IDF:
HVACTemplate:Plant:Chiller:ObjectReference[LINK]
This object references a detailed chiller object and adds it to an HVACTemplate:Plant:ChilledWaterLoop. The user must create a complete detailed chiller object with all required curve or performance objects. The detailed chiller object is referenced by object type and name and the chiller will be automatically to the chilled water loop branches and equipment list.[LINK]
Field: Name[LINK]
The name of this object.
Field: Chiller Object Type[LINK]
The object type of the referenced chiller. Select from one of the following supported chiller object types:
Field: Chiller Name[LINK]
The object name of the referenced chiller.
Field: Priority[LINK]
Enter the priority number of the chiller where 1 is the highest priority, 2 is just lower, 3 is lower than 2, etc. This is used if Chiller Plant Operation Scheme Type is set to Default in HVACTemplate:Plant:ChilledWaterLoop. Equipment is operated in order of the priority number. This allows multiple chillers to be sequenced.
An example in an IDF:
HVACTemplate:Plant:Tower[LINK]
A cooling tower is described with this object. To define multiple cooling towers, use multiple HVACTemplate:Plant:Tower objects and use the Sizing Factor field to apportion the total capacity if autosizing.
Field: Name[LINK]
The name used to reference the HVACTemplate:Plant:Tower object.
Field: Tower Type[LINK]
The choices for this field are
The EnergyPlus equipment object types which are used are [CoolingTower:SingleSpeed](../input-output-reference/page-026.html#coolingtowersinglespeed) or [CoolingTower:TwoSpeed](../input-output-reference/page-026.html#coolingtowertwospeed). These equipment type keys must be used if setting up a user-defined condenser plant operation scheme.
Field: High-Speed Nominal Capacity[LINK]
Applicable for Tower Type Single Speed and Two Speed. This field may be set to autosize. If this field is set to autosize, then the Low-Speed Nominal Capacity and the Free Convection Capacity must also be autosized. The units are W. This numeric input field contains the “nominal” heat rejection capacity of the cooling tower in watts under high-speed fan operation, with entering water at 35C (95F), leaving water at 29.4C (85F), entering air at 25.6C (78F) wetbulb and 35C (95F) drybulb temperatures. The design water flow rate is assumed to be 5.382E-8 m3/s per watt of high-speed nominal capacity (3 gpm/ton). 125% of this nominal tower capacity gives the actual tower heat rejection at these operating conditions (based on historical assumption that the tower must dissipate 0.25W of compressor heat for every watt of heat removed by the evaporator).
Field: High-Speed Fan Power[LINK]
The tower fan electric consumption when at high speed. Applicable for Tower Type Single Speed and Two Speed. This field may be set to autosize. The units are W.
Field: Low-Speed Nominal Capacity[LINK]
Applicable only for Tower Type Two Speed. This field may be set to autosize. If this field is set to autosize, then the High-Speed Nominal Capacity and the Free Convection Capacity must also be autosized. The units are W. This numeric input field contains the “nominal” heat rejection capacity of the cooling tower in watts under low-speed fan operation, with entering water at 35C (95F), leaving water at 29.4C (85F), entering air at 25.6C (78F) wetbulb and 35C (95F) drybulb temperatures. The design water flow rate is assumed to be 5.382E-8 m3/s per watt of high-speed nominal tower capacity (input field above). 125% of this nominal tower capacity gives the actual tower heat rejection at these operating conditions (based on historical assumption that the tower must dissipate 0.25W of compressor heat for every watt of heat removed by the evaporator). The value specified for this field must be greater than zero but less than the value specified for the field “Tower High-Speed Nominal Capacity”.
Field: Low-Speed Fan Power[LINK]
The tower fan electric consumption when at low speed. Applicable only for Tower Type Two Speed. This field may be set to autosize. The units are W.
Field: Free Convection Capacity[LINK]
Applicable for Tower Type Single Speed and Two Speed. This field may be set to autosize. If this field is set to autosize, then the High-Speed Nominal Capacity and the Low-Speed Nominal Capacity must also be autosized. The units are W. This numeric input field contains the “nominal” heat rejection capacity of the cooling tower in watts when the tower is in the “free convection” regime (water flow exists but tower fan is turned off), with entering water at 35C (95F), leaving water at 29.4C (85F), entering air at 25.6C (78F) wetbulb and 35C (95F) drybulb temperatures. The design water flow rate is assumed to be 5.382E-8 m3/s per watt of high-speed nominal tower capacity (input field above). 125% of this free convection tower capacity gives the actual tower heat rejection at these operating conditions (based on historical assumption that the tower must dissipate 0.25W of compressor heat for every watt of heat removed by the evaporator). If the user does not wish to model “free convection”, then this field should be set to 0.0.
Field: Priority[LINK]
Enter the priority number of the tower where 1 is the highest priority, 2 is just lower, 3 is lower than 2, etc. This is used if Condenser Plant Operation Scheme Type is set to Default in HVACTemplate:Plant:ChilledWaterLoop. Equipment is operated in order of the priority number. This allows multiple towers to be sequenced.
Field: Sizing Factor
This optional numeric field allows the user to specify a sizing factor for this component. The sizing factor is used when the component design inputs are autosized: the autosizing calculations are performed as usual and the results are multiplied by the sizing factor. Sizing factor allows the user to size a component to meet part of the design load while continuing to use the autosizing feature.For this component the tower object inputs that would be altered by the sizing factor are:
Design Water Flow Rate;
Air Flow Rate at High Fan Speed;
Fan Power at High Fan Speed;
U-Factor Times Area Value at High Fan Speed;
Air Flow Rate at Low Fan Speed (for two-speed tower);
Fan Power at Low Fan Speed (for two-speed tower);
U-Factor Times Area Value at Low Fan Speed (for two-speed tower);
Air Flow Rate in Free Convection Regime;
U-Factor Times Area Value at Free Convection Air Flow Rate.
Note that the U-Factor Times Area Value at High Fan Speed is not multiplied by the Sizing Factor. Instead the design tower load is multiplied by the sizing factor and the design UA then calculated as usual. The U-Factor Times Area Value at Low Fan Speed is set to 60% of the full load design UA. The U-Factor Times Area Value at Free Convection Air Flow Rate is set to 10% of the design Tower UA.
An example in an IDF:
HVACTemplate:Plant:Tower:ObjectReference[LINK]
This object references a detailed cooling tower object and adds it to an HVACTemplate:Plant:ChilledWaterLoop or MixedWaterLoop. The user must create a complete detailed cooling tower object with all required curve or performance objects. The detailed cooling tower object is referenced by object type and name and the tower will be automatically to the chilled water loop or mixed water loop branches and equipment list.[LINK]
Field: Name[LINK]
The name of this object.
Field: Cooling Tower Object Type[LINK]
The object type of the referenced tower. Select from one of the following supported tower object types:
Field: Cooling Tower Name[LINK]
The object name of the referenced tower.
Field: Priority[LINK]
Enter the priority number of the tower where 1 is the highest priority, 2 is just lower, 3 is lower than 2, etc. This is used if Condenser Plant Operation Scheme Type is set to Default in HVACTemplate:Plant:ChilledWaterLoop or MixedWaterLoop. Equipment is operated in order of the priority number. This allows multiple towers to be sequenced.
An example in an IDF:
HVACTemplate:Plant:HotWaterLoop[LINK]
The piping systems that connect the hot water coils in the HVAC template objects with the boilers are described with this object. The piping systems are called loops and this object describes the controls and pumps on the loops. Only one of these objects should be defined in an input file and all hot water coils from HVAC template objects are served with this object.
Field: Name[LINK]
The name used to designate the HVACTemplate:Plant:HotWaterLoop.
Field: Pump Schedule Name[LINK]
Leave this field blank if the hot water pump is always available. If a schedule name is specified, those times that the pump is available should be specified as 1.0. Those times that the pump is not available should have a zero value in the schedule specified. Please note that this is not a schedule of when the system is providing hot water to the coils but a schedule of when it can provide hot water to the coils.
Field: Pump Control Type[LINK]
The choices for this field are
The default value is Intermittent.
If the pump control type is Continuous, the pump will run according to the Pump Schedule (see above) regardless of whether or not there is a load. If the pump control type is Intermittent, the pump will run if a load is sensed and will shut off if there is no load on the loop.
Field: Hot Water Plant Operation Scheme Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all times operating in order of Priority specified in HVACTemplate:Plant:Boiler objects. If a different scheme is to be used to sequence the boilers, then this entry should be set to User Defined.
If User Defined option is chosen, then additional EnergyPlus objects must be defined in the IDF file such as shown below depending on the type of plant operation control scheme chosen:
The default value is Default.
Field: Hot Water Plant Equipment Operation Schemes Name[LINK]
This field should contain the name of a [PlantEquipmentOperationSchemes](../input-output-reference/page-023.html#plantequipmentoperationschemes) object only when the previous field is set to User Defined. It is ignored if Hot Water Plant Operation Scheme Type is Default.
Field: Hot Water Setpoint Schedule Name[LINK]
Enter the name of a hot water setpoint schedule that has values that change at different times of the year. If a constant set point is needed simply leave this field blank and the value in the next field will be used at all times. The values in the schedule are in degrees C. This field is ignored if the Hot Water Setpoint Reset Type is something other than None.
Field: Hot Water Design Setpoint[LINK]
Enter the hot water setpoint temperature to be used for sizing the hot water loop and associated equipment in degrees C. If the Hot Water Setpoint Schedule is blank and the Hot Water Setpoint Reset Type is None, then this value will be used as the setpoint at all times.
Field: Hot Water Pump Configuration[LINK]
The choices for this field are
The default value is ConstantFlow. The variable flow option simulates a pump with variable flow to boilers and coils, excess bypassed. The constant flow option simulates constant flow to boilers and coils, excess bypassed.
The operation of a constant speed pump is fairly straightforward. If the user designates a constant speed pump that is operating continuously, the pump will run regardless of whether or not there is a load. This may have the net effect of adding heat to the loop if no equipment is turned on. If the pump is constant speed and operates intermittently, the pump will run at its capacity if a load is sensed and will shut off if there is no load on the loop.
A variable speed pump is defined with maximum and minimum flow rates that are the physical limits of the device. If there is no load on the loop and the pump is operating intermittently, then the pump can shutdown. For any other condition such as the loop having a load and the pump is operating intermittently or the pump is continuously operating (regardless of the loading condition), the pump will operate and select a flow somewhere between the minimum and maximum limits. In these cases where the pump is running, it will try to meet the flow request made by demand side components.
Field: Hot Water Pump Rated Head[LINK]
The rated head of the hot water pump in Pa. The default value is 179352 Pa which is equivalent to 60 feet H2O.
Field: Hot Water Setpoint Reset Type[LINK]
Select the type of automatic reset control for the Hot Water supply temperature. The choices are:
The default is None.
Field: Hot Water Setpoint at Outdoor Dry Bulb Low[LINK]
The Hot Water setpoint temperature in C when the outdoor dry-bulb is at or below the low limit (Hot Water Reset Outdoor Dry Bulb Low). The default is –6.7C.
Field: Hot Water Reset Outdoor Dry Bulb Low[LINK]
The low limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or below this temperature, the setpoint is the value of Hot Water Setpoint at Outdoor Dry Bulb Low. The default is 82.2C.
Field: Hot Water Setpoint at Outdoor Dry Bulb High[LINK]
The Hot Water setpoint temperature in C when the outdoor dry-bulb is at or above the high limit (Hot Water Reset Outdoor Dry Bulb Low). The default is 10.0C.
Field: Hot Water Reset Outdoor Dry Bulb High[LINK]
The high limit of outdoor dry-bulb temperature in C for outdoor air reset control. When the outdoor dry-bulb is at or above this temperature, the setpoint is the value of Hot Water Setpoint at Outdoor Dry Bulb High. The default is 65.6C.
Field: Hot Water Pump Type[LINK]
Describes the type of pump configuration used for the hot water loop. The options include:
Field: Supply Side Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is present in the hot water loop. The choices for this field are
Field: Demand Side Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is present in the hot water loop. The choices for this field are
Field: Fluid Type[LINK]
This field determines the type of fluid used for the chilled water loop. The following options are available:
Field: Loop Design Delta Temperature[LINK]
The temperature difference used in sizing the loop flow rate. The default is 11C.
Field: Maximum Outdoor Dry Bulb Temperature[LINK]
The maximum outdoor dry bulb temperature that the hot water loops operate.
Field: Load Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to sequence equipment operation in order to meet the plant loop demand. Currently, three schemes are functional. Sequential uses each piece of equipment to its maximum part load ratio and will operate the last required piece of equipment between its minimum and maximum part load ratio in order to meet the loop demand. Optimal operates each piece of equipment at its optimal part load ratio and will operate the last component between its minimum and maximum part load ratio in order to meet the loop demand. Uniform evenly distributes the loop demand among all available components on the equipment list for a given load range.
As shown in an IDF:
HVACTemplate:Plant:Boiler[LINK]
A boiler or purchased heating source is described with this object. To define multiple boilers, use multiple HVACTemplate:Plant:Boiler objects and use the Sizing Factor field to apportion the total capacity if autosizing.
Field: Name[LINK]
The name used to reference the HVACTemplate:Plant:Boiler object.
Field: Boiler Type[LINK]
While EnergyPlus has a variety of boiler options, the only choices currently for this field are:
The EnergyPlus equipment object types which are used are [DistrictHeating](../input-output-reference/page-024.html#districtheating) or [Boiler:HotWater](../input-output-reference/page-024.html#boilerhotwater). These equipment type keys must be used if setting up a user-defined chiller plant operation scheme.
Field: Capacity[LINK]
This field may be set to autosize, which means that the capacity is based on the peak loads during the design days. This numeric field contains the design heating capacity of the boiler. This capacity should be at the design water flow rates. The units are in W.
Field: Efficiency[LINK]
This numeric field contains the heating efficiency (as a fraction between 0 and 1) of the boiler’s burner. Not applicable if Boiler Type is DistrictHotWater.
Field: Fuel Type[LINK]
The choices for this field are
Not applicable if Boiler Type is DistrictHotWater
Field: Priority[LINK]
Enter the priority number of the boiler where 1 is the highest priority, 2 is just lower, 3 is lower than 2, etc. This is used if Boiler Plant Operation Scheme Type is set to Default in HVACTemplate:Plant:HotWaterLoop. Equipment is operated in order of the priority number. This allows multiple boilers to be sequenced.
Field: Sizing Factor[LINK]
This optional numeric field allows the user to specify a sizing factor for this component. The sizing factor is used when the component design inputs are autosized: the autosizing calculations are performed as usual and the results are multiplied by the sizing factor. For this component the boiler object inputs that would be altered by the sizing factor are: Nominal Capacity and Design Water Flow Rate. Sizing factor allows the user to size a component to meet part of the design load while continuing to use the autosizing feature.
Field: Minimum Part Load Ratio[LINK]
This numeric field contains the minimum part load ratio. If the ratio of demand to boiler nominal capacity is less than the minimum part load ratio, then the Min PLR will determine the operating PLR. The expected range is between 0 and 1. If this field is left blank, the default value is 0.0.
Field: Maximum Part Load Ratio[LINK]
This numeric field contains the maximum part load ratio. If the ratio of demand to boiler nominal capacity is greater than the maximum part load ratio, then the Max PLR will determine the operating PLR. This value may exceed 1, but the normal range is between 0 and 1.1. If this field is left blank, the default value is 1.1.
Field: Optimum Part Load Ratio[LINK]
This numeric field contains the optimum part load ratio. This is the part load ratio at which the boiler performs at its maximum efficiency. If this field is left blank, the default value is 1.0.
Field: Water Outlet Upper Temperature Limit[LINK]
This numeric field contains the outlet temperature upper limit. If this field is left blank, the default value is 100.0ºC.
An example in an IDF:
HVACTemplate:Plant:Boiler:ObjectReference[LINK]
This object references a detailed boiler object and adds it to an HVACTemplate:Plant:HotWaterLoop or MixedWaterLoop. The user must create a complete detailed boiler object with all required curve or performance objects. The detailed boiler object is referenced by object type and name and the boiler will be automatically to the hot water or mixed water loop branches and equipment list.[LINK]
Field: Name[LINK]
The name of this object.
Field: Boiler Object Type[LINK]
The object type of the referenced boiler. Select from one of the following supported boiler object types:
Field: Boiler Name[LINK]
The object name of the referenced boiler.
Field: Priority[LINK]
Enter the priority number of the boiler where 1 is the highest priority, 2 is just lower, 3 is lower than 2, etc. This is used if Hot Water Plant Operation Scheme Type is set to Default in HVACTemplate:Plant:ChilledWaterLoop or MixedWaterLoop. Equipment is operated in order of the priority number. This allows multiple boioilers to be sequenced.
An example in an IDF:
HVACTemplate:Plant:MixedWaterLoop[LINK]
This object simulates the central plant loop portion of a water source heat pump system. Often many HVACTemplate:Zone:WaterToAirHeatPump objects will be used in a building along with a single HVACTemplate:Plant:MixedWaterLoop that contains one or more cooling towers and boilers. The piping systems are called loops and this object describes the controls and pumps on the loops. Only one of these objects should be defined in an input file.
Field: Name[LINK]
The name used to designate the HVACTemplate:Plant:MixedWaterLoop.
Field: Pump Schedule Name[LINK]
Leave this field blank if the water pump is always available. If a schedule name is specified, those times that the pump is available should be specified as 1.0. Those times that the pump is not available should have a zero value in the schedule specified. Please note that this is not a schedule of when the system is providing water to the water-to-air heat pumps but a schedule of when it can provide water to the water-to-air heat pumps.
Field: Pump Control Type[LINK]
The choices for this field are
The default value is Intermittent.
If the pump control type is Continuous, the pump will run according to the Pump Schedule (see above) regardless of whether or not there is a load. If the pump control type is Intermittent, the pump will run if a load is sensed and will shut off if there is no load on the loop.
Field: Operation Scheme Type[LINK]
The choices for this field are:
Default operation type makes all equipment available at all times operating in order of Priority specified in HVACTemplate:Plant:Boiler objects. If a different scheme is to be used to sequence the boilers, then this entry should be set to User Defined.
If User Defined option is chosen, then additional EnergyPlus objects must be defined in the IDF file such as shown below depending on the type of plant operation control scheme chosen:
The default value is Default.
Field: Equipment Operation Schemes Name[LINK]
This field should contain the name of a [PlantEquipmentOperationSchemes](../input-output-reference/page-023.html#plantequipmentoperationschemes) object only when the previous field is set to User Defined. It is ignored if Hot Water Plant Operation Scheme Type is Default.
Field: High Temperature Setpoint Schedule Name[LINK]
Enter the name of a high temperature setpoint schedule that has values that change at different times of the year. If a constant set point is needed simply leave this field blank and the value in the next field will be used at all times. The values in the schedule are in degrees C.
Field: High Temperature Design Setpoint[LINK]
Enter the high temperature setpoint temperature to be used for sizing the water loop and associated equipment in degrees C. If the High Temperature Setpoint Schedule is blank, then this value will be used as the setpoint at all times. The default is 33C.
Field: Low Temperature Setpoint Schedule Name[LINK]
Enter the name of a low temperature setpoint schedule that has values that change at different times of the year. If a constant set point is needed simply leave this field blank and the value in the next field will be used at all times. The values in the schedule are in degrees C.
Field: Low Temperature Design Setpoint[LINK]
Enter the low temperature setpoint temperature to be used for sizing the water loop and associated equipment in degrees C. If the Low Temperature Setpoint Schedule is blank, then this value will be used as the setpoint at all times. The default is 20C.
Field: Water Pump Configuration[LINK]
The choices for this field are
The default value is ConstantFlow. The variable flow option simulates a pump with variable flow to boilers, cooling towers, and water to air heat pump, excess bypassed. The constant flow option simulates constant flow to boilers, cooling towers, and water to air heat pumps, excess bypassed.
The operation of a constant speed pump is fairly straightforward. If the user designates a constant speed pump that is operating continuously, the pump will run regardless of whether or not there is a load. This may have the net effect of adding heat to the loop if no equipment is turned on. If the pump is constant speed and operates intermittently, the pump will run at its capacity if a load is sensed and will shut off if there is no load on the loop.
A variable speed pump is defined with maximum and minimum flow rates that are the physical limits of the device. If there is no load on the loop and the pump is operating intermittently, then the pump can shutdown. For any other condition such as the loop having a load and the pump is operating intermittently or the pump is continuously operating (regardless of the loading condition), the pump will operate and select a flow somewhere between the minimum and maximum limits. In these cases where the pump is running, it will try to meet the flow request made by demand side components.
Field: Water Pump Rated Head[LINK]
The rated head of the hot water pump in Pa. The default value is 179352 Pa which is equivalent to 60 feet H2O.
Field: Water Pump Type[LINK]
Describes the type of pump configuration used for mixed water loop. The options include:
Field: Supply Side Bypass Pipe[LINK]
The field determines if a supply side bypass pipe is present in the mixed water loop. The choices for this field are
Field: Demand Side Bypass Pipe[LINK]
The field determines if a demand side bypass pipe is present in the mixed water loop. The choices for this field are
Field: Fluid Type[LINK]
This field determines the type of fluid used for the mixed water loop. The following options are available:
Field: Loop Design Delta Temperature[LINK]
The temperature difference used in sizing the loop flow rate. The default is 5.6C.
Field: Load Distribution Scheme[LINK]
The Load Distribution Scheme selects the algorithm used to sequence equipment operation in order to meet the plant loop demand. Currently, three schemes are functional. Sequential uses each piece of equipment to its maximum part load ratio and will operate the last required piece of equipment between its minimum and maximum part load ratio in order to meet the loop demand. Optimal operates each piece of equipment at its optimal part load ratio and will operate the last component between its minimum and maximum part load ratio in order to meet the loop demand. Uniform evenly distributes the loop demand among all available components on the equipment list for a given load range.
As shown in an IDF:
Documentation content copyright © 1996-2026 The Board of Trustees of the University of Illinois and the Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory. All rights reserved. EnergyPlus is a trademark of the US Department of Energy.
This documentation is made available under the EnergyPlus Open Source License v1.0.