Group – Design Objects[LINK]
In order for EnergyPlus to successfully calculate zone
design heating and cooling loads and air flow rates and for
the program to use these results to automatically size the
HVAC components a number of input objects must be present and
certain object input fields must be entered.
The input file should contain a SimulationControl
object. The 1st field Do [Zone](../input-output-reference/page-011.html#zone)
Sizing Calculation should be entered as Yes.
This will cause a zone sizing simulation to be done using all
the sizing periods in the input file as weather. If there are
no air or water loops in the HVAC input fields 2 and 3 can be
set to No. If there are one or more air loops (i.e.,
there is at least one [AirLoopHVAC](../input-output-reference/page-028.html#airloophvac)
object in the input file) then the 2nd field Do
System Sizing Calculation should be entered as
Yes. If there are one or more water loops (Plant Loop
objects) then the 3rd field Do Plant Sizing
Calculation should be set to Yes. Finally either
the 4th field (Run Simulation for Sizing
Periods) or the 5th field (Run Simulation
for Weather File Run Periods) should be set to
Yes in order to autosize the components and do a real
simulation using the autosized components. The component
autosizing calculations are done on the first pass through the
HVAC system in the real simulation.
There must be at least 2 (up to any number)
SizingPeriod objects present. Normally one will be for summer
conditions and one for winter. The summer day should normally
have the field Day Type set to
SummerDesignDay. The winter design day should
normally have Day Type set to
WinterDesignDay.
To apply a global sizing factor include the Sizing:Parameters
object.
For each controlled zone in the input file there
should be a corresponding
Sizing:Zone](page-011.html#zone) object. Similarly for each [AirLoopHVAC](../input-output-reference/page-028.html#airloophvac)
there should be a [Sizing:System object. And for each Plant or
Condenser Loop there should be a Sizing:Plant
object. Note however that if a controlled zone has no
corresponding [Zone](../input-output-reference/page-011.html#zone)
Sizing object the data from the first [Zone](../input-output-reference/page-011.html#zone)
Sizing object will be used. Thus if all the zone sizing
information is the same only one [Zone](../input-output-reference/page-011.html#zone)
Sizing object need be entered.
Only controlled zones are included in the zone and
system sizing calculations. Thus for a design air flow rate to
be calculated for a zone, it must contain a thermostat
even though it might not need or have a thermostat in the
full simulation. An illustration would be a three zone
building with a packaged single zone system and a thermostat
in one of the zones. In order for the two slave zones to be
included in the design air flow calculations they must be
treated as if they have a thermostat: there must be a [ZoneControl:Thermostat](../input-output-reference/page-037.html#zonecontrolthermostat)
for each of the slave zones.
Some attention should be paid to schedules. In a weekly
schedule object the 9th and 10th day
schedules are for summer and winter design days respectively.
This means that if a SizingPeriod object has field Day
Type set to SummerDesignDay the day schedule for
summer sizing periods will be in effect. Similarly if a
SizingPeriod object has field Day Type set to
WinterDesignDay the day schedule for winter sizing
periods will be in effect. Some possible applications of this
capability are:
internal loads (lights, equipment, occupancy) to maximum all day for cooling and to zero all day for heating;
#. setting heating and cooling thermostat set points to constant values (no set up or set back);
#. setting heating and cooling equipment to be always on.
None of these applications are necessarily recommended but
these and other uses of the special summer/winter design day
schedules may prove useful for specific situations.
- Other than zone thermostat setpoints, the sizing
calculations generally know nothing about the system control
inputs such as setpoints and availability schedules. The user
must coordinate sizing inputs with the actual simulation
control inputs.
- The sizing calculations only recognize the presence of
central heating and cooling coils, preheat and precool coils
and reheat coils. These are assumed to deliver the various
supply temperatures specified in the Sizing:System and
Sizing:Zone objects. The impact of ther components such as
heat recovery, dehumidifiers, fans, and pumps are not
accounted for in the sizing calculations.
Component Autosizing[LINK]
For autosizing to occur at the component level the user
must enter the special value autosize in the numeric
fields for which autosizing is available. Those fields can be
found by looking at the Energy+.idd data dictionary file or
under individual object details in this document. Fields that
can be autosized are denoted with the comment
\autosizable. The components and fields that are
autosizable are listed in the following table. Note that
spaces may be inserted in object names to facilitate
readability.
Table: Details of Autosizable Objects/Fields
Component / Object Name|Autosizable Fields ———————–|——————
AirConditioner:VariableRefrigerantFlow
|Gross Rated Total Cooling Capacity |Gross Rated Heating
Capacity |Resistive Defrost Heater Capacity |Water Condenser
Volume Flow Rate |Evaporative Condenser Air Flow Rate
|Evaporative Condenser Pump Rated Power Consumption AirLoopHVAC
|Design Supply Air Flow Rate AirLoopHVAC:Unitary:Furnace:HeatCool
|Maximum Supply Air Temperature |Supply Air Flow Rate During
Cooling Operation |Supply Air Flow Rate During Heating
Operation |Supply Air Flow Rate When No Cooling or Heating is
Needed AirLoopHVAC:Unitary:Furnace:HeatOnly
|Maximum Supply Air Temperature |Supply Air Flow Rate
AirLoopHVAC:UnitaryHeatCool
|Maximum Supply Air Temperature |Supply Air Flow Rate During
Cooling Operation |Supply Air Flow Rate During Heating
Operation |Supply Air Flow Rate When No Cooling or Heating is
Needed AirLoopHVAC:UnitaryHeatCool:VAVChangeoverBypass
|System Air Flow Rate During Cooling Operation |System Air
Flow Rate During Heating Operation |System Air Flow Rate When
No Cooling or Heating is Needed |Outdoor Air Flow Rate During
Cooling Operation |Outdoor Air Flow Rate During Heating
Operation |Outdoor Air Flow Rate When No Cooling or Heating is
Needed AirLoopHVAC:UnitaryHeatOnly
|Maximum Supply Air Temperature |Supply Air Flow Rate
AirLoopHVAC:UnitaryHeatPump:AirToAir
|Supply Air Flow Rate During Cooling Operation |Supply Air
Flow Rate During Heating Operation |Supply Air Flow Rate When
No Cooling or Heating is Needed |Maximum Supply Air
Temperature from Supplemental Heater AirLoopHVAC:UnitaryHeatPump:AirToAir:MultiSpeed
|Maximum Supply Air Temperature from Supplemental Heater
|Supply Air Flow Rate When No Cooling or Heating is Needed
|Speed 1 Supply Air Flow Rate During Heating Operation |Speed
2 Supply Air Flow Rate During Heating Operation |Speed 3
Supply Air Flow Rate During Heating Operation |Speed 4 Supply
Air Flow Rate During Heating Operation |Speed 1 Supply Air
Flow Rate During Cooling Operation |Speed 2 Supply Air Flow
Rate During Cooling Operation |Speed 3 Supply Air Flow Rate
During Cooling Operation |Speed 4 Supply Air Flow Rate During
Cooling Operation AirLoopHVAC:UnitaryHeatPump:WaterToAir
|Supply Air Flow Rate |Maximum Supply Air Temperature from
Supplemental Heater AirLoopHVAC:UnitarySystem
|Supply Air Flow Rate During Cooling Operation |Supply Air
Flow Rate During Heating Operation |Supply Air Flow Rate When
No Cooling or Heating is Required |Maximum Supply Air
Temperature AirTerminal:DualDuct:ConstantVolume
|Maximum Air Flow Rate AirTerminal:DualDuct:VAV
|Maximum Damper Air Flow Rate AirTerminal:DualDuct:VAV:OutdoorAir
|Maximum Terminal Air Flow Rate AirTerminal:SingleDuct:ConstantVolume:CooledBeam
|Supply Air Volumetric Flow Rate |Maximum Total Chilled Water
Volumetric Flow Rate |Number of Beams |Beam Length AirTerminal:SingleDuct:ConstantVolume:FourPipeInduction
|Maximum Total Air Flow Rate |Maximum Hot Water Flow Rate
|Maximum Cold Water Flow Rate AirTerminal:SingleDuct:ConstantVolume:Reheat
|Maximum Air Flow Rate |Maximum Hot Water or Steam Flow Rate
AirTerminal:SingleDuct:ParallelPIU:Reheat
|Maximum Primary Air Flow Rate |Maximum Secondary Air Flow
Rate |Minimum Primary Air Flow Fraction |Fan On Flow Fraction
|Maximum Hot Water or Steam Flow Rate AirTerminal:SingleDuct:SeriesPIU:Reheat
|Maximum Air Flow Rate |Maximum Primary Air Flow Rate |Minimum
Primary Air Flow Fraction |Maximum Hot Water or Steam Flow
Rate AirTerminal:SingleDuct:Uncontrolled
|Maximum Air Flow Rate AirTerminal:SingleDuct:VAV:HeatAndCool:NoReheat
|Maximum Air Flow Rate AirTerminal:SingleDuct:VAV:HeatAndCool:Reheat
|Maximum Air Flow Rate |Maximum Hot Water or Steam Flow Rate
AirTerminal:SingleDuct:VAV:NoReheat
|Maximum Air Flow Rate AirTerminal:SingleDuct:VAV:Reheat
|Maximum Air Flow Rate |Maximum Hot Water or Steam Flow Rate
AirTerminal:SingleDuct:VAV:Reheat:VariableSpeedFan
|Maximum Cooling Air Flow Rate |Maximum Heating Air Flow Rate
|Maximum Hot Water or Steam Flow Rate Boiler:HotWater
|Nominal Capacity |Design Water Flow Rate Boiler:Steam
|Nominal Capacity Branch
|Maximum Flow Rate Chiller:Absorption
|Nominal Capacity |Nominal Pumping Power |Design Chilled Water
Flow Rate |Design Condenser Water Flow Rate |Design Generator
Fluid Flow Rate Chiller:Absorption:Indirect
|Nominal Capacity |Nominal Pumping Power |Design Chilled Water
Flow Rate |Design Condenser Water Flow Rate |Design Generator
Fluid Flow Rate Chiller:CombustionTurbine
|Nominal Capacity |Design Chilled Water Flow Rate |Design
Condenser Water Flow Rate |Gas Turbine Engine Capacity
Chiller:ConstantCOP
|Nominal Capacity |Design Chilled Water Flow Rate |Design
Condenser Water Flow Rate Chiller:Electric
|Nominal Capacity |Design Chilled Water Flow Rate |Design
Condenser Fluid Flow Rate |Design Heat Recovery Water Flow
Rate Chiller:Electric:EIR
|Reference Capacity |Reference Chilled Water Flow Rate
|Reference Condenser Fluid Flow Rate |Design Heat Recovery
Water Flow Rate Chiller:Electric:ReformulatedEIR
|Reference Capacity |Reference Chilled Water Flow Rate
|Reference Condenser Water Flow Rate |Design Heat Recovery
Water Flow Rate Chiller:EngineDriven
|Nominal Capacity |Design Chilled Water Flow Rate |Design
Condenser Water Flow Rate ChillerHeater:Absorption:DirectFired
|Nominal Cooling Capacity |Design Chilled Water Flow Rate
|Design Condenser Water Flow Rate |Design Hot Water Flow Rate
ChillerHeater:Absorption:DoubleEffect
|Nominal Cooling Capacity |Design Chilled Water Flow Rate
|Design Condenser Water Flow Rate |Design Hot Water Flow Rate
ChillerHeaterPerformance:Electric:EIR
|Reference Cooling Mode Evaporator Capacity |Design Chilled
Water Flow Rate |Design Condenser Water Flow Rate Coil:Cooling:DX:MultiSpeed
|Speed 1 Gross Rated Total Cooling Capacity |Speed 1 Gross
Rated Sensible Heat Ratio |Speed 1 Rated Air Flow Rate |Speed
1 Evaporative Condenser Air Flow Rate |Speed 1 Rated
Evaporative Condenser Pump Power Consumption |Speed 2 Gross
Rated Total Cooling Capacity |Speed 2 Gross Rated Sensible
Heat Ratio |Speed 2 Rated Air Flow Rate |Speed 2 Evaporative
Condenser Air Flow Rate |Speed 2 Rated Evaporative Condenser
Pump Power Consumption |Speed 3 Gross Rated Total Cooling
Capacity |Speed 3 Gross Rated Sensible Heat Ratio |Speed 3
Rated Air Flow Rate |Speed 3 Evaporative Condenser Air Flow
Rate |Speed 3 Rated Evaporative Condenser Pump Power
Consumption |Speed 4 Gross Rated Total Cooling Capacity |Speed
4 Gross Rated Sensible Heat Ratio |Speed 4 Rated Air Flow Rate
|Speed 4 Evaporative Condenser Air Flow Rate |Speed 4 Rated
Evaporative Condenser Pump Power Consumption Coil:Cooling:DX:SingleSpeed
|Gross Rated Total Cooling Capacity |Gross Rated Sensible Heat
Ratio |Rated Air Flow Rate |Evaporative Condenser Air Flow
Rate |Evaporative Condenser Pump Rated Power Consumption
Coil:Cooling:DX:SingleSpeed:ThermalStorage
|Rated Evaporator Air Flow Rate |Cooling Only Mode Rated Total
Evaporator Cooling Capacity |Evaporative Condenser Pump Rated
Power Consumption Coil:Cooling:DX:TwoSpeed
|High Speed Gross Rated Total Cooling Capacity |High Speed
Rated Sensible Heat Ratio |High Speed Rated Air Flow Rate |Low
Speed Gross Rated Total Cooling Capacity |Low Speed Gross
Rated Sensible Heat Ratio |Low Speed Rated Air Flow Rate |High
Speed Evaporative Condenser Air Flow Rate |High Speed
Evaporative Condenser Pump Rated Power Consumption |Low Speed
Evaporative Condenser Air Flow Rate |Low Speed Evaporative
Condenser Pump Rated Power Consumption Coil:Cooling:DX:VariableRefrigerantFlow
|Gross Rated Total Cooling Capacity |Gross Rated Sensible Heat
Ratio |Rated Air Flow Rate Coil:Cooling:DX:VariableSpeed
|Gross Rated Total Cooling Capacity At Selected Nominal Speed
Level |Rated Air Flow Rate At Selected Nominal Speed Level
|Evaporative Condenser Pump Rated Power Consumption Coil:Cooling:Water
|Design Water Flow Rate |Design Air Flow Rate |Design Inlet
Water Temperature |Design Inlet Air Temperature |Design Outlet
Air Temperature |Design Inlet Air Humidity Ratio |Design
Outlet Air Humidity Ratio Coil:Cooling:Water:DetailedGeometry
|Maximum Water Flow Rate |Tube Outside Surface Area |Total
Tube Inside Area |Fin Surface Area |Minimum Airflow Area |Coil
Depth |Fin Diameter |Number of Tubes per Row Coil:Cooling:WaterToAirHeatPump:EquationFit
|Rated Air Flow Rate |Rated Water Flow Rate |Gross Rated Total
Cooling Capacity |Gross Rated Sensible Cooling Capacity
Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit
|Gross Rated Total Cooling Capacity At Selected Nominal Speed
Level |Rated Air Flow Rate At Selected Nominal Speed Level
|Rated Water Flow Rate At Selected Nominal Speed Level
Coil:Heating:DX:MultiSpeed
|Resistive Defrost Heater Capacity |Speed 1 Gross Rated
Heating Capacity |Speed 1 Rated Air Flow Rate |Speed 2 Gross
Rated Heating Capacity |Speed 2 Rated Air Flow Rate |Speed 3
Gross Rated Heating Capacity |Speed 3 Rated Air Flow Rate
|Speed 4 Gross Rated Heating Capacity |Speed 4 Rated Air Flow
Rate Coil:Heating:DX:SingleSpeed
|Gross Rated Heating Capacity |Rated Air Flow Rate |Resistive
Defrost Heater Capacity Coil:Heating:DX:VariableRefrigerantFlow
|Gross Rated Heating Capacity |Rated Air Flow Rate Coil:Heating:DX:VariableSpeed
|Rated Heating Capacity At Selected Nominal Speed Level |Rated
Air Flow Rate At Selected Nominal Speed Level |Resistive
Defrost Heater Capacity Coil:Heating:Electric
|Nominal Capacity Coil:Heating:Electric:MultiStage
|Stage 1 Nominal Capacity |Stage 2 Nominal Capacity |Stage 3
Nominal Capacity |Stage 4 Nominal Capacity Coil:Heating:Gas
|Nominal Capacity Coil:Heating:Gas:MultiStage
|Stage 1 Nominal Capacity |Stage 2 Nominal Capacity |Stage 3
Nominal Capacity |Stage 4 Nominal Capacity Coil:Heating:Steam
|Maximum Steam Flow Rate Coil:Heating:Water
|U-Factor Times Area Value |Maximum Water Flow Rate |Rated
Capacity Coil:Heating:WaterToAirHeatPump:EquationFit
|Rated Air Flow Rate |Rated Water Flow Rate |Gross Rated
Heating Capacity Coil:Heating:WaterToAirHeatPump:VariableSpeedEquationFit
|Rated Heating Capacity At Selected Nominal Speed Level |Rated
Air Flow Rate At Selected Nominal Speed Level |Rated Water
Flow Rate At Selected Nominal Speed Level CoilPerformance:DX:Cooling
|Gross Rated Total Cooling Capacity |Gross Rated Sensible Heat
Ratio |Rated Air Flow Rate |Evaporative Condenser Air Flow
Rate |Evaporative Condenser Pump Rated Power Consumption
CondenserLoop
|Maximum Loop Flow Rate Controller:OutdoorAir
|Minimum Outdoor Air Flow Rate |Maximum Outdoor Air Flow Rate
Controller:WaterCoil
|Controller Convergence Tolerance |Maximum Actuated Flow
CoolingTower:SingleSpeed
|Design Water Flow Rate |Design Air Flow Rate |Design Fan
Power |Design U-Factor Times Area Value CoolingTower:TwoSpeed
|Design Water Flow Rate |High Fan Speed Air Flow Rate |High
Fan Speed Fan Power |High Fan Speed U-Factor Times Area Value
CoolingTower:VariableSpeed
|Design Water Flow Rate |Design Air Flow Rate |Design Fan
Power CoolingTower:VariableSpeed:Merkel
|Nominal Capacity |Design Water Flow Rate |Design Air Flow
Rate U-Factor Times Area Value EvaporativeCooler:Indirect:ResearchSpecial
|Secondary Fan Flow Rate EvaporativeFluidCooler:SingleSpeed
|Design Air Flow Rate |Design Air Flow Rate Fan Power |Design
Air Flow Rate U-factor Times Area Value |Design Water Flow
Rate EvaporativeFluidCooler:TwoSpeed
|High Fan Speed Air Flow Rate |High Fan Speed Fan Power |High
Fan Speed U-factor Times Area Value |Design Water Flow Rate
Fan:ComponentModel
|Maximum Flow Rate |Minimum Flow Rate |Motor Fan Pulley Ratio
|Belt Maximum Torque |Maximum Motor Output Power |Maximum VFD
Output Power Fan:ConstantVolume
|Maximum Flow Rate Fan:OnOff
|Maximum Flow Rate FanPerformance:NightVentilation
|Maximum Flow Rate Fan:VariableVolume
|Maximum Flow Rate FluidCooler:SingleSpeed
|Design Air Flow Rate U-factor Times Area Value |Design Water
Flow Rate |Design Air Flow Rate |Design Air Flow Rate Fan
Power FluidCooler:TwoSpeed
|High Fan Speed U-factor Times Area Value |Design Water Flow
Rate |High Fan Speed Air Flow Rate |High Fan Speed Fan Power
HeaderedPumps:ConstantSpeed
|Total Rated Flow Rate |Rated Power Consumption HeaderedPumps:VariableSpeed
|Total Rated Flow Rate |Rated Power Consumption HeatExchanger:AirToAir:SensibleAndLatent
|Nominal Supply Air Flow Rate HeatExchanger:FluidToFluid
|Loop Demand Side Design Flow Rate |Loop Supply Side Design
Flow Rate |Heat Exchanger U-Factor Times Area Value Humidifier:Steam:Electric
|Rated Power HVACTemplate:Plant:Boiler
|Capacity HVACTemplate:Plant:Chiller
|Capacity HVACTemplate:Plant:Tower
|High Speed Nominal Capacity |High Speed Fan Power |Low Speed
Nominal Capacity |Low Speed Fan Power |Free Convection
Capacity HVACTemplate:System:ConstantVolume
|Supply Fan Maximum Flow Rate |Heating Coil Capacity |Maximum
Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate
|Humidifier Rated Electric Power HVACTemplate:System:DedicatedOutdoorAir
|Supply Fan Flow Rate |DX Cooling Coil Gross Rated Total
Capacity |DX Cooling Coil Gross Rated Sensible Heat Ratio
|Humidifier Rated Electric Power HVACTemplate:System:DualDuct
|Main Supply Fan Maximum Flow Rate |Cold [Duct](../input-output-reference/page-021.html#duct)
Supply Fan Maximum Flow Rate |Hot [Duct](../input-output-reference/page-021.html#duct)
Supply Fan Maximum Flow Rate |Heating Coil Capacity |Maximum
Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate
|Humidifier Rated Electric Power HVACTemplate:System:PackagedVAV
|Supply Fan Maximum Flow Rate |Supply Fan Minimum Flow Rate
|Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross
Rated Sensible Heat Ratio |Heating Coil Capacity |Maximum
Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate
|Humidifier Rated Electric Power HVACTemplate:System:Unitary
|Supply Fan Maximum Flow Rate |Cooling Coil Gross Rated Total
Capacity |Cooling Coil Gross Rated Sensible Heat Ratio
|Heating Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum
Outdoor Air Flow Rate |Humidifier Rated Electric Power
HVACTemplate:System:UnitaryHeatPump:AirToAir
|Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate
|No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total
Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heat
Pump Heating Coil Gross Rated Capacity |Supplemental Heating
Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum Outdoor
Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:UnitarySystem
|Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate
|No Load Supply Air Flow Rate |DX Cooling Coil Gross Rated
Total Capacity |DX Cooling Coil Gross Rated Sensible Heat
Ratio |Heating Coil Gross Rated Capacity |Supplemental Heating
or Reheat Coil Capacity |Maximum Outdoor Air Flow Rate
|Minimum Outdoor Air Flow Rate |Humidifier Rated Electric
Power HVACTemplate:System:VAV
|Supply Fan Maximum Flow Rate |Supply Fan Minimum Flow Rate
|Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate
|Humidifier Rated Electric Power HVACTemplate:System:VRF
|Gross Rated Total Cooling Capacity |Gross Rated Heating
Capacity |Resistive Defrost Heater Capacity |Water Condenser
Volume Flow Rate |Evaporative Condenser Air Flow Rate
|Evaporative Condenser Pump Rated Power Consumption HVACTemplate:Zone:BaseboardHeat
|Baseboard Heating Capacity HVACTemplate:Zone:ConstantVolume
|Supply Air Maximum Flow Rate |Baseboard Heating Capacity
HVACTemplate:Zone:DualDuct
|Supply Air Maximum Flow Rate |Baseboard Heating Capacity
HVACTemplate:Zone:FanCoil
|Supply Air Maximum Flow Rate |Baseboard Heating Capacity
HVACTemplate:Zone:IdealLoadsAirSystem
|Maximum Heating Air Flow Rate |Maximum Sensible Heating
Capacity |Maximum Cooling Air Flow Rate |Maximum Total Cooling
Capacity HVACTemplate:Zone:PTAC
|Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate
|No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total
Capacity |Cooling Coil Gross Rated Sensible Heat Ratio
|Heating Coil Capacity |Baseboard Heating Capacity HVACTemplate:Zone:PTHP
|Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate
|No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total
Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heat
Pump Heating Coil Gross Rated Capacity |Supplemental Heating
Coil Capacity |Baseboard Heating Capacity HVACTemplate:Zone:Unitary
|Supply Air Maximum Flow Rate |Baseboard Heating Capacity
HVACTemplate:Zone:VAV
|Supply Air Maximum Flow Rate |Baseboard Heating Capacity
HVACTemplate:Zone:VAV:FanPowered
|Primary Supply Air Maximum Flow Rate |Primary Supply Air
Minimum Flow Fraction |Secondary Supply Air Maximum Flow Rate
|Parallel Fan On Flow Fraction |Baseboard Heating Capacity
HVACTemplate:Zone:VAV:HeatAndCool
|Supply Air Maximum Flow Rate |Baseboard Heating Capacity
HVACTemplate:Zone:VRF
|Supply Air Flow Rate During Cooling Operation |Supply Air
Flow Rate When No Cooling is Needed |Supply Air Flow Rate
During Heating Operation |Supply Air Flow Rate When No Heating
is Needed |Outdoor Air Flow Rate During Cooling Operation
|Outdoor Air Flow Rate During Heating Operation |Outdoor Air
Flow Rate When No Cooling or Heating is Needed |Cooling Coil
Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible
Heat Ratio |Heat Pump Heating Coil Gross Rated Capacity
|Baseboard Heating Capacity HVACTemplate:Zone:WaterToAirHeatPump
|Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate
|No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total
Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heat
Pump Heating Coil Gross Rated Capacity |Supplemental Heating
Coil Capacity |Baseboard Heating Capacity PlantComponent:TemperatureSource
|Design Volume Flow Rate PlantEquipmentOperation:ComponentSetpoint
|Component 1 Flow Rate |Component 2 Flow Rate |Component 3
Flow Rate |Component 4 Flow Rate |Component 5 Flow Rate
|Component 6 Flow Rate |Component 7 Flow Rate |Component 8
Flow Rate |Component 9 Flow Rate |Component 10 Flow Rate
PlantLoop
|Maximum Loop Flow Rate Pump:ConstantSpeed
|Rated Flow Rate |Rated Power Consumption Pump:VariableSpeed
|Rated Flow Rate |Rated Power Consumption Pump:VariableSpeed:Condensate
|Rated Flow Rate |Rated Power Consumption Sizing:System
|Design Outdoor Air Flow Rate SolarCollector:FlatPlate:PhotovoltaicThermal
|Design Flow Rate ThermalStorage:ChilledWater:Mixed
|Use Side Design Flow Rate |Source Side Design Flow Rate
ThermalStorage:ChilledWater:Stratified
|Use Side Design Flow Rate |Source Side Design Flow Rate
UnitarySystemPerformance:HeatPump:Multispeed
|Speed 1 Supply Air Flow Ratio During Heating Operation |Speed
1 Supply Air Flow Ratio During Cooling Operation |Speed 2
Supply Air Flow Ratio During Heating Operation |Speed 2 Supply
Air Flow Ratio During Cooling Operation |Speed 3 Supply Air
Flow Ratio During Heating Operation |Speed 3 Supply Air Flow
Ratio During Cooling Operation |Speed 4 Supply Air Flow Ratio
During Heating Operation |Speed 4 Supply Air Flow Ratio During
Cooling Operation WaterHeater:Mixed
|Tank Volume |Heater Maximum Capacity |Use Side Design Flow
Rate |Source Side Design Flow Rate WaterHeater:Stratified
|Tank Volume |Tank Height |Heater 1 Capacity |Use Side Design
Flow Rate |Source Side Design Flow Rate ZoneHVAC:Baseboard:Convective:Electric
|Nominal Capacity ZoneHVAC:Baseboard:Convective:Water
|U-Factor Times Area Value |Maximum Water Flow Rate ZoneHVAC:Baseboard:RadiantConvective:Electric
|Nominal Capacity ZoneHVAC:Baseboard:RadiantConvective:Steam
|Maximum Steam Flow Rate ZoneHVAC:Baseboard:RadiantConvective:Water
|Rated Capacity |Maximum Water Flow Rate ZoneHVAC:EnergyRecoveryVentilator
|Supply Air Flow Rate |Exhaust Air Flow Rate ZoneHVAC:EvaporativeCoolerUnit
|Design Supply Air Flow Rate ZoneHVAC:FourPipeFanCoil
|Maximum Supply Air Flow Rate |Maximum Outdoor Air Flow Rate
|Maximum Cold Water Flow Rate |Maximum Hot Water Flow Rate
ZoneHVAC:HighTemperatureRadiant
|Maximum Power Input ZoneHVAC:IdealLoadsAirSystem
|Maximum Heating Air Flow Rate |Maximum Sensible Heating
Capacity |Maximum Cooling Air Flow Rate |Maximum Total Cooling
Capacity ZoneHVAC:LowTemperatureRadiant:Electric
|Maximum Electrical Power to Panel ZoneHVAC:LowTemperatureRadiant:VariableFlow
|Hydronic Tubing Length |Maximum Hot Water Flow |Maximum Cold
Water Flow ZoneHVAC:OutdoorAirUnit
|Outdoor Air Flow Rate |Exhaust Air Flow Rate ZoneHVAC:PackagedTerminalAirConditioner
|Supply Air Flow Rate During Cooling Operation |Supply Air
Flow Rate During Heating Operation |Supply Air Flow Rate When
No Cooling or Heating is Needed |Outdoor Air Flow Rate During
Cooling Operation |Outdoor Air Flow Rate During Heating
Operation |Outdoor Air Flow Rate When No Cooling or Heating is
Needed ZoneHVAC:PackagedTerminalHeatPump
|Supply Air Flow Rate During Cooling Operation |Supply Air
Flow Rate During Heating Operation |Supply Air Flow Rate When
No Cooling or Heating is Needed |Outdoor Air Flow Rate During
Cooling Operation |Outdoor Air Flow Rate During Heating
Operation |Outdoor Air Flow Rate When No Cooling or Heating is
Needed |Maximum Supply Air Temperature from Supplemental
Heater ZoneHVAC:TerminalUnit:VariableRefrigerantFlow
|Supply Air Flow Rate During Cooling Operation |Supply Air
Flow Rate When No Cooling is Needed |Supply Air Flow Rate
During Heating Operation |Supply Air Flow Rate When No Heating
is Needed |Outdoor Air Flow Rate During Cooling Operation
|Outdoor Air Flow Rate During Heating Operation |Outdoor Air
Flow Rate When No Cooling or Heating is Needed ZoneHVAC:UnitHeater
|Maximum Supply Air Flow Rate |Maximum Hot Water or Steam Flow
Rate ZoneHVAC:UnitVentilator
|Maximum Supply Air Flow Rate |Minimum Outdoor Air Flow Rate
|Maximum Outdoor Air Flow Rate ZoneHVAC:VentilatedSlab
|Maximum Air Flow Rate |Minimum Outdoor Air Flow Rate |Maximum
Outdoor Air Flow Rate ZoneHVAC:WaterToAirHeatPump
|Supply Air Flow Rate During Cooling Operation |Supply Air
Flow Rate During Heating Operation |Supply Air Flow Rate When
No Cooling or Heating is Needed |Outdoor Air Flow Rate During
Cooling Operation |Outdoor Air Flow Rate During Heating
Operation |Outdoor Air Flow Rate When No Cooling or Heating is
Needed |Maximum Supply Air Temperature from Supplemental
Heater ZoneHVAC:WindowAirConditioner
|Maximum Supply Air Flow Rate |Maximum Outdoor Air Flow
Rate
There are 3 places in the input where the user can impose
sizing factors.
In Sizing Parameters (object: Sizing:Parameters), the user
can specify an over-all sizing factor. This factor is applied
to all the zone design loads and air flow rates resulting from
the zone sizing calculations.
In [Zone](../input-output-reference/page-011.html#zone)
Sizing (object: Sizing:[Zone](../input-output-reference/page-011.html#zone)),
the user can specify a sizing factor for a specific zone. The
factor is applied to the calculated zone design loads and air
flow rates for the zone named in the Sizing:[Zone](../input-output-reference/page-011.html#zone)
object. This sizing factor overrides the global sizing factor.
That is, a zone sizing factor, if specified, replaces the
global sizing factor for the named zone.
For some plant components (basically all central chillers,
boilers and cooling towers) the user can specify a sizing
factor that modifies the autosized component capacity and flow
rates. These factors are applied after the application of
global or zone sizing factors. They are primarily used to
split the design load between multiple components. These
sizing factors can change the autosizing of the associated
loops and pumps. The following rules are followed the effect
of plant component sizing factors on loops and pumps.
For supply side branches, the sizing factors of all
components in series on the branch are summed and the result
becomes the branch sizing factor. If there is a branch pump
its autosized design flow rate is multiplied by the branch
sizing factor.
For each loop, if the average of the branch sizing factors
is less than 1, the loop sizing factor is set equal to the sum
of the branch sizing factors. If the average is greater than
1, the loop sizing factor is set equal to the maximum of the
branch sizing factors. The loop sizing factor is applied to
the loop design flow rate (if autosized) and to the loop pump
flow rate (if autosized).
Mixed user-specified and autosized inputs can be
successfully used if the following points and suggestions are
followed.
Each component is autosized independently. Thus user input
for a flow rate in one component will have no effect on other
components’ autosized flow rates. For instance, specifying the
chilled water loop pump’s rated flow rate will have no effect
on the autosizing of the chiller’s design evaporator flow rate
or on the plant loop’s autosized maximum loop flow rate.
Within a component it is best to autosize all inputs are
enter specified values for all inputs. For example, in a
chiller, if only the nominal capaciity is user-specified, the
autosized chilled water flow rate may not be consistent with
the specified capacity.
Sizing information flows only from the sizing objects to
the components. The sizing calculations have no knowledge of
user-specified values in a component. The only exception to
this rule is that plant loop sizing will collect all component
design water flow rates whether autosized or
user-specified.
If the user wants to specify a zone or system air flow rate
it should be done using the Sizing:Zone
and Sizing:System
objects rather than done in the individual components.
The plant loop flow rates are sized from the total design
demand of the components connected to each loop. The
components demanding water need not be autosized for the plant
loop autosizing to work successfully. So the user could
specify all the air side components and autosize all the plant
loops and plant components. Or specify the chilled water loop
flow rate, chilled water pump inputs and chiller inputs and
let the condenser loop and tower autosize.
Component Sizing Output[LINK]
The results of the component autosizing calculations are
reported on the eplusout.eio file. For each component
field that has been autosized the object type, object name,
field description with unit, and value are printed out as
comma separated data on a line beginning with Component
Sizing. Examples of this are shown in the Output Details
and Examples document.
The complete list of objects that have autosized fields is
shown in the following table. Note that spaces may be inserted
in object names to facilitate readability.
Table: Complete list of Objects with autosized Fields
Object Name|Object Name ———–|———–
AirConditioner:VariableRefrigerantFlow|AirLoopHVAC
AirLoopHVAC:Unitary:Furnace:HeatCool|AirLoopHVAC:Unitary:Furnace:HeatOnly
AirLoopHVAC:UnitaryHeatCool|AirLoopHVAC:UnitaryHeatCool:VAVChangeoverBypass
AirLoopHVAC:UnitaryHeatOnly|AirLoopHVAC:UnitaryHeatPump:AirToAir
AirLoopHVAC:UnitaryHeatPump:AirToAir:MultiSpeed|AirLoopHVAC:UnitaryHeatPump:WaterToAir
AirLoopHVAC:UnitarySystem|AirTerminal:DualDuct:ConstantVolume
AirTerminal:DualDuct:VAV|AirTerminal:DualDuct:VAV:OutdoorAir
AirTerminal:SingleDuct:ConstantVolume:CooledBeam|AirTerminal:SingleDuct:ConstantVolume:FourPipeInduction
AirTerminal:SingleDuct:ConstantVolume:Reheat|AirTerminal:SingleDuct:ParallelPIU:Reheat
AirTerminal:SingleDuct:SeriesPIU:Reheat|AirTerminal:SingleDuct:Uncontrolled
AirTerminal:SingleDuct:VAV:HeatAndCool:NoReheat|AirTerminal:SingleDuct:VAV:HeatAndCool:Reheat
AirTerminal:SingleDuct:VAV:NoReheat|AirTerminal:SingleDuct:VAV:Reheat
AirTerminal:SingleDuct:VAV:Reheat:VariableSpeedFan|Boiler:HotWater
Boiler:Steam|Branch
Chiller:Absorption|Chiller:Absorption:Indirect
Chiller:CombustionTurbine|Chiller:ConstantCOP
Chiller:Electric|Chiller:Electric:EIR
Chiller:Electric:ReformulatedEIR|Chiller:EngineDriven
ChillerHeater:Absorption:DirectFired|ChillerHeater:Absorption:DoubleEffect
ChillerHeaterPerformance:Electric:EIR|Coil:Cooling:DX:MultiSpeed
Coil:Cooling:DX:SingleSpeed|Coil:Cooling:DX:SingleSpeed:ThermalStorage
Coil:Cooling:DX:TwoSpeed|Coil:Cooling:DX:VariableRefrigerantFlow
Coil:Cooling:DX:VariableSpeed|Coil:Cooling:Water
Coil:Cooling:Water:DetailedGeometry|Coil:Cooling:WaterToAirHeatPump:EquationFit
Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit|Coil:Heating:DX:MultiSpeed
Coil:Heating:DX:SingleSpeed|Coil:Heating:DX:VariableRefrigerantFlow
Coil:Heating:DX:VariableSpeed|Coil:Heating:Electric
Coil:Heating:Electric:MultiStage|Coil:Heating:Gas
Coil:Heating:Gas:MultiStage|Coil:Heating:Steam
Coil:Heating:Water|Coil:Heating:WaterToAirHeatPump:EquationFit
Coil:Heating:WaterToAirHeatPump:VariableSpeedEquationFit|CoilPerformance:DX:Cooling
CondenserLoop|Controller:OutdoorAir
Controller:WaterCoil|CoolingTower:SingleSpeed
CoolingTower:TwoSpeed|CoolingTower:VariableSpeed
CoolingTower:VariableSpeed:Merkel|EvaporativeCooler:Indirect:ResearchSpecial
EvaporativeFluidCooler:SingleSpeed|EvaporativeFluidCooler:TwoSpeed
Fan:ComponentModel|Fan:ConstantVolume
Fan:OnOff|FanPerformance:NightVentilation
Fan:VariableVolume|FluidCooler:SingleSpeed
FluidCooler:TwoSpeed|HeaderedPumps:ConstantSpeed
HeaderedPumps:VariableSpeed|HeatExchanger:AirToAir:SensibleAndLatent
HeatExchanger:FluidToFluid|Humidifier:Steam:Electric
HVACTemplate:Plant:Boiler|HVACTemplate:Plant:Chiller
HVACTemplate:Plant:Tower|HVACTemplate:System:ConstantVolume
HVACTemplate:System:DedicatedOutdoorAir|HVACTemplate:System:DualDuct
HVACTemplate:System:PackagedVAV|HVACTemplate:System:Unitary
HVACTemplate:System:UnitaryHeatPump:AirToAir|HVACTemplate:System:UnitarySystem
HVACTemplate:System:VAV|HVACTemplate:System:VRF
HVACTemplate:Zone:BaseboardHeat|HVACTemplate:Zone:ConstantVolume
HVACTemplate:Zone:DualDuct|HVACTemplate:Zone:FanCoil
HVACTemplate:Zone:IdealLoadsAirSystem|HVACTemplate:Zone:PTAC
HVACTemplate:Zone:PTHP|HVACTemplate:Zone:Unitary
HVACTemplate:Zone:VAV|HVACTemplate:Zone:VAV:FanPowered
HVACTemplate:Zone:VAV:HeatAndCool|HVACTemplate:Zone:VRF
HVACTemplate:Zone:WaterToAirHeatPump|PlantComponent:TemperatureSource
PlantEquipmentOperation:ComponentSetpoint|PlantLoop
Pump:ConstantSpeed|Pump:VariableSpeed
Pump:VariableSpeed:Condensate|Sizing:System
SolarCollector:FlatPlate:PhotovoltaicThermal|ThermalStorage:ChilledWater:Mixed
ThermalStorage:ChilledWater:Stratified|UnitarySystemPerformance:HeatPump:Multispeed
WaterHeater:Mixed|WaterHeater:Stratified
ZoneHVAC:Baseboard:Convective:Electric|ZoneHVAC:Baseboard:Convective:Water
ZoneHVAC:Baseboard:RadiantConvective:Electric|ZoneHVAC:Baseboard:RadiantConvective:Steam
ZoneHVAC:Baseboard:RadiantConvective:Water|ZoneHVAC:EnergyRecoveryVentilator
ZoneHVAC:EvaporativeCoolerUnit|ZoneHVAC:FourPipeFanCoil
ZoneHVAC:HighTemperatureRadiant|ZoneHVAC:IdealLoadsAirSystem
ZoneHVAC:LowTemperatureRadiant:Electric|ZoneHVAC:LowTemperatureRadiant:VariableFlow
ZoneHVAC:OutdoorAirUnit|ZoneHVAC:PackagedTerminalAirConditioner
ZoneHVAC:PackagedTerminalHeatPump|ZoneHVAC:TerminalUnit:VariableRefrigerantFlow
ZoneHVAC:UnitHeater|ZoneHVAC:UnitVentilator
ZoneHVAC:VentilatedSlab|ZoneHVAC:WaterToAirHeatPump [ZoneHVAC:WindowAirConditioner](../input-output-reference/page-032.html#zonehvacwindowairconditioner)|
In EnergyPlus the autosizing calculations start with a
calculation of the zone design air flow rates using zone by
zone design day simulations. The resulting zone design air
flow rates and daily air flow sequences are used in the
subsequent HVAC and central plant air and fluid flow design
calculations and in the component autosizing calculations. The
user can override or change the calculated zone design air
flow rates in several ways.
- The user can enter a value for Sizing Factor in
the Sizing:Parameters object (see description
below).
- The user can specify a zone level Zone Sizing
Factor in each Sizing:Zone object.
- For each zone the user can input a Cooling Design Air
Flow Rate and/or a Heating Design Air Flow Rate
(and specify Cooling Design Air Flow Method =
Flow/Zone and Heating Design Air Flow Method =
Flow/Zone). These user inputs override the calculated
values. The program divides the user input cooling or heating
design air flow rate by the calculated values and uses the
result as a zone sizing factor to multiply all the elements in
the design heating and cooling air flow and load sequences.
From this point the design calculations proceed as usual.
Using the results of the zone design air flow rate
calculation (including any user input or altered flow rates)
EnergyPlus proceeds to calculate central air system flow rates
and cooling and heating loads. The results of this calculation
can be overridden in the following way.
For each system (AirLoopHVAC](page-028.html#airloophvac)),
in the corresponding [Sizing:System object, specify
Cooling Design Air Flow Method to be
Flow/System and input a value for Cooling Design
Air Flow Rate. **Similarly for heating specify
Heating Design Air Flow Method to be
Flow/System and input a value for Heating Design
Air Flow Rate.
DesignSpecification:OutdoorAir[LINK]
This object allows for the outdoor air requirements to be
defined in a common location for use by other objects. This
object may be referenced by name from other objects (e.g., VAV
terminal units) as required to identify an outdoor air
quantity for use by that object. Note that a zone name Is not
included as an input to this zone outdoor air definition and
the number of people in a zone, zone floor area, and zone
volume can only be determined after this object has been
referenced by another. A single zone outdoor air definition
may be referenced by multiple objects to specify that the same
outdoor air requirements are used by those objects or
multiple zone outdoor air objects may be defined and
referenced by other objects as needed. If multiple zone
outdoor air definitions are used, each outdoor air definition
must have a unique name.
Unique identifying name. Any reference to this name by
other objects will denote that the following outdoor air
requirements will be used.
Field: Outdoor Air
Method[LINK]
The input must be either Flow/Person,
Flow/Area, Flow/[Zone](../input-output-reference/page-011.html#zone),
AirChanges/Hour, Sum, or Maximum.
Flow/Person means the program will use the input from
the field Outdoor Air Flow per Person and the actual
zone occupancy to calculate a zone outdoor air flow rate.
Flow/Area means that the program will use the input
from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area and the actual zone floor area as the zone
outdoor air flow rate. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone)
as the zone outdoor air flow rate. AirChanges/Hour
means that the program will use the input from the field
Air Changes per Hour and the actual zone volume
(divided by 3600 seconds per hour) as the zone outdoor air
flow rate. Sum means that the flows calculated from
the fields Outdoor Air Flow per Person, Outdoor
Air Flow per Area, Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone),
and Air Changes per Hour (using the associated
conversions to m3/s for each field) will be added
to obtain the zone outdoor air flow rate. Maximum
means that the maximum flow derived from Outdoor Air Flow
per Person, Outdoor Air Flow per Area, Outdoor Air
Flow per [Zone](../input-output-reference/page-011.html#zone),
and Air Changes per Hour (using the associated
conversions to m3/s for each field) will be used as
the zone outdoor air flow rate. The default is
Flow/Person.
Field: Outdoor Air
Flow per Person[LINK]
The design outdoor air volume flow rate per person for this
zone in cubic meters per second per person. 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 during sizing calculations and
are applied during the remainder of the simulation.
This input is used if Outdoor Air Method is one of
Outdoor Air Flow per Person, Sum, or
Maximum.
Field:
Outdoor Air Flow per Zone Floor Area[LINK]
The design outdoor air volume flow rate per square meter of
floor area (units are m3/s-m2). This
input is used if Outdoor Air Method is Flow/Area,
Sum or Maximum. The default value for this field
is 0.
Field: Outdoor Air
Flow 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.
The default value for this field is 0.
Field:
Outdoor Air Flow Changes per Hour[LINK]
The design outdoor air volume flow rate in air changes per
hour. This factor is used along with the [Zone](../input-output-reference/page-011.html#zone)
Volume and converted to cubic meters per second. This input
field is used if Outdoor Air Method is
AirChanges/Hour, Sum or Maximum. The default
value for this field is 0.
Field:
Outdoor Air Flow Rate Fraction Schedule Name[LINK]
This field is the name of schedule that defines how outdoor
air requirements change over time. The field is optional. If
used, then the schedule values are multiplied by the outdoor
air flow rate defined by the previous fields. The schedule
values must be between 0 and 1, inclusive.
An IDF example:
DesignSpecification:OutdoorAir
ZoneOAData, !- Name
Sum, !- Outdoor Air Method
0.00944, !- Outdoor Air Flow per Person {m3/s}
0.00305, !- Outdoor Air Flow per Zone Floor Area {m3/s-m2}
, !- Outdoor Air Flow per Zone {m3/s}
, !- Outdoor Air Flow Air Changes per Hour
OARequirements Sched; !- Outdoor Air Flow Rate Fraction Schedule Name
Schedule:Compact,
OARequirements Sched, !- Name
Any Number, !- Schedule Type Limits Name
Through: 12/31, !- Field 1
For: Weekdays SummerDesignDay WinterDesignDay, !- Field 2
Until: 24:00, 1.0, !- Field 4
For: AllOtherDays, !- Field 5
Until: 24:00, 0.5; !- Field 7
DesignSpecification:ZoneAirDistribution[LINK]
This object is used to describe the air distribution
effectiveness and fraction of secondary recirculation air
(return air not directly mixed with outdoor air) of a zone. It
is referenced by the Sizing:Zone
and [Controller:MechanicalVentilation](../input-output-reference/page-051.html#controllermechanicalventilation)
objects.
The unique user assigned name for an instance of this
object. Any other object referencing this object will use this
name.
Field:
Zone Air Distribution Effectiveness in Cooling Mode[LINK]
The positive numeric input for this field is the zone air
distribution effectiveness when the zone is in cooling mode.
Default value of this field is 1.0. ASHRAE Standard 62.1-2010
provides typical values.
Field:
Zone Air Distribution Effectiveness in Heating Mode[LINK]
The positive numeric input for this field is the zone air
distribution effectiveness when the zone is in heating mode.
Default value of this field is 1.0. ASHRAE Standard 62.1-2010
provides typical values as follows:
Field:
Zone Air Distribution Effectiveness Schedule Name[LINK]
This optional field input points to a schedule with values
of zone air distribution effectiveness. It provides a more
flexible way of specifying zone air distribution effectiveness
if it changes with time and/or system operating status and
controls. If the schedule is specified, the zone air
distribution effectiveness in cooling mode and heating mode
will be ignored.
Field:
Zone Secondary Recirculation Fraction[LINK]
The non-negative numeric input for this field is the
fraction of a zone’s recirculation air that does not directly
mix with the outdoor air. The zone secondary recirculation
fraction Er is determined by the designer based on system
configuration. For plenum return systems with secondary
recirculation (e.g., fan-powered VAV with plenum return) Er is
usually less than 1.0, although values may range from 0.1 to
1.2 depending upon the location of the ventilation zone
relative to other zones and the air handler. For ducted return
systems with secondary recirculation (e.g., fan-powered VAV
with ducted return), Er is typically 0.0, while for those with
system-level recirculation (e.g, dual-fan dual-duct systems
with ducted return) Er is typically 1.0. For other system
types, Er is typically 0.75. Minimum is 0.0, and default is
0.0 for single-path systems (also to maintain backward
compatibility). For parallel fan-powered VAV systems, the
secondary ventilation path only functions (Er > 0.0) when
the fans in the VAV boxes operate, which is during heating.
The local ventilation path and the benefits of secondary
recirculation disappear during cooling, when the local
parallel fans are off (Er = 0.0).
An example of this in an IDF context is shown:
DesignSpecification:ZoneAirDistribution,
CM DSZAD ZN_1_FLR_1_SEC_1, !- Name
1, !- Zone Air Distribution Effectiveness in Cooling Mode {dimensionless}
1, !- Zone Air Distribution Effectiveness in Heating Mode {dimensionless}
; !- Zone Air Distribution Effectiveness Schedule Name
Sizing:Parameters[LINK]
This object allows the user to specify global heating and
cooling sizing ratios. These ratios will be applied at the
zone level to all of the zone heating and cooling loads and
air flow rates. These new loads and air flow rates are then
used to calculate the system level flow rates and capacities
and are used in all component sizing calculations.
The user can also specify the width (in load timesteps) of
a moving average window which can be used to smooth the
calculated zone design flow sequences. The use of this
parameter is described below.
Field: Heating Sizing
Factor[LINK]
The global heating sizing ratio applied to all of the zone
design heating loads and air flow rates.
Field: Cooling Sizing
Factor[LINK]
The global cooling sizing ratio applied to all of the zone
design cooling loads and air flow rates
Field: Timesteps
in Averaging Window[LINK]
The number of load timesteps in the zone design flow
sequence averaging window. The default is 1, in which case the
calculated zone design flow rates are averaged over the load
timestep.
The zone design air flow rate calculation is performed
assuming a potentially infinite supply of heating or cooling
air at a fixed temperature. Thus the calculated design air
flow rate will always be able to meet any load or change in
load no matter how large or abrupt. In reality air flow rates
are limited by duct sizes and fan capacities. The idealized
zone design flow calculation may result in unrealistically
large flow rates, especially if the user is performing the
sizing calculations using thermostat schedules with night
setup or setback. The calculated zone design flow rates are
always averaged over the load timestep. The user may want to
perform a broader average to mitigate the effect of thermostat
setup and setback and prevent the warm up or cool down flow
rates from dominating the design flow rate calculation..
Specifying the width of the averaging window allows the user
to do this.
For example, if the load calculation timestep is 15 minutes
and the user specifies the Timesteps in Averaging [Window](../input-output-reference/page-011.html#window)
to be 4, the zone design air flows will be averaged over a
time period of 1 hour. Specifying 8 would result in averaging
over a 2 hour period.
Sizing Parameters
Outputs[LINK]
The sizing factors and the averaging window size are
reported out on the eplusout.eio file. An example
is:
! <Load Timesteps in Zone Design Calculation Averaging Window>, Value
Timesteps in Averaging Window, 1
! <Heating Sizing Factor Information>, Sizing Factor ID, Value
Heating Sizing Factor, Global, 1.3000
Heating Sizing Factor, Zone SPACE1-1, 1.3000
Heating Sizing Factor, Zone SPACE2-1, 1.3000
Heating Sizing Factor, Zone SPACE3-1, 1.3000
Heating Sizing Factor, Zone SPACE4-1, 1.3000
Heating Sizing Factor, Zone SPACE5-1, 1.3000
! <Cooling Sizing Factor Information>, Sizing Factor ID, Value
Cooling Sizing Factor, Global, 1.3000
Cooling Sizing Factor, Zone SPACE1-1, 1.3000
Cooling Sizing Factor, Zone SPACE2-1, 1.3000
Cooling Sizing Factor, Zone SPACE3-1, 1.3000
Cooling Sizing Factor, Zone SPACE4-1, 1.3000
Cooling Sizing Factor, Zone SPACE5-1, 1.3000
OutputControl:Sizing:Style[LINK]
As described early in the document (see: EnergyPlus Output
Processing), the user may select the “style” for the sizing
result files (epluszsz., eplusssz.). This object applies to
all sizing output files.
OutputControl:Sizing:Style,
\memo default style for the Sizing output files is comma -- this works well for
\memo importing into spreadsheet programs such as Excel(tm) but not so well for word
\memo processing progams -- there tab may be a better choice. fixed puts spaces between
\memo the "columns"
\unique-object
A1; \field Column Separator
\required-field
\type choice
\key Comma
\key Tab
\key Fixed
Field: Column Separator[LINK]
For this field, the desired separator for columns is
entered. “Comma” creates comma separated fields/columns in the
outputs (eplus.csv files are created). “Tab” creates tab
separated fields/columns in the outputs (eplus.tab files are
created). “Fixed” creates space separated fields/columns in
the outputs (eplus.txt files are created) but these are not
necessarily lined up for easy printing.
Note that both tab and comma separated files easily import
into Excel™ or other spreadsheet programs. The tab delimited
files can also be viewed by text editors, word processing
programs and easily converted to “tables” within those
programs.
The Sizing:Zone
object provides the data needed to perform a zone design air
flow calculation for a single zone. This calculation assumes a
variable amount of supply air at a fixed temperature and
humidity. The information needed consists of the zone inlet
supply air conditions: temperature and humidity ratio for
heating and cooling. The calculation is done for every design
day included in the input. The maximum cooling load and air
flow and the maximum heating load and air flow are then saved
for the system level design calculations and for the component
automatic sizing calculations.
The Sizing:Zone
object is also the place where the user can specify the design
outdoor air flow rate by referencing the name of a design
specification outdoor air object. This can be specified in a
number of ways (ref. DesignSpecification:OutdoorAir).This data
is saved for use in the system sizing calculation or for
sizing zone components that use outdoor air.
The user can also place limits on the heating and design
cooling air flow rates. See Heating Design Air Flow
Method and Cooling Design Air Flow Method below
and the explanations of the various heating and cooling flow
input fields.
Field: Zone Name[LINK]
The name of the [Zone](../input-output-reference/page-011.html#zone)
corresponding to this Sizing:[Zone](../input-output-reference/page-011.html#zone)
object. This is the zone for which the design air flow
calculation will be made using the input data of this
Sizing:[Zone](../input-output-reference/page-011.html#zone)
Object.
The input must be either
SupplyAirTemperature or
TemperatureDifference. SupplyAirTemperature
means that the user inputs from the fields of [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature will be used to
determine the zone cooling design air flow rates.
TemperatureDifference means that the user inputs from
the fields of [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Difference will be used
to determine the zone cooling design air flow rates.
Field:
Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
cooling design air flow rate calculation. Air is supplied to
the zone at this temperature during the cooling design day
simulation, The zone load is met by varying the zone air flow
rate. The maximum zone flow rate is saved as the zone cooling
design air flow rate. This field is only used when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method =
SupplyAirTemperature.
Field:
Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between cooling design supply
air temperature and room air temperature in degrees Celsius
for the zone cooling design air flow rate calculation. Air is
supplied to the zone at this temperature during the cooling
design day simulation. The zone load is met by varying the
zone air flow rate. The maximum zone flow rate is saved as the
zone cooling design air flow rate. This field is only used
when [Zone](../input-output-reference/page-011.html#zone)
Cooling Design Supply Air Temperature Input Method =
TemperatureDifference.
The input must be either
SupplyAirTemperature or
TemperatureDifference. SupplyAirTemperature
means that the user inputs from the fields of [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature will be used to
determine the zone heating design air flow rates.
TemperatureDifference means that the user inputs from
the fields of [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Difference will be used
to determine the zone heating design air flow rates.
Field:
Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone
heating design air flow rate calculation. Air is supplied to
the zone at this temperature during the heating design day
simulation, The zone load is met by varying the zone air flow
rate. The maximum zone flow rate is saved as the zone heating
design air flow rate. This field is only used when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method =
SupplyAirTemperature.
Field:
Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply
air temperature and room air temperature in degrees Celsius
for the zone heating design air flow rate calculation. Air is
supplied to the zone at this temperature during the heating
design day simulation. The zone load is met by varying the
zone air flow rate. The maximum zone flow rate is saved as the
zone heating design air flow rate. This field is only used
when [Zone](../input-output-reference/page-011.html#zone)
Heating Design Supply Air Temperature Input Method =
TemperatureDifference.
Field:
Zone Cooling Design Supply Air Humidity Ratio[LINK]
The humidity ratio in kilograms of water per kilogram of
dry air of the supply air in the zone cooling design air flow
rate calculation.
Field:
Zone Heating Design Supply Air Humidity Ratio[LINK]
The humidity ratio in kilograms of water per kilogram of
dry air of the supply air in the zone heating design air flow
rate calculation.
Field:
Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a DesignSpecification:OutdoorAir
object which specifies the design outdoor air flow rate for
the zone.
Field: Zone Heating
Sizing Factor[LINK]
This input is a zone level heating sizing ratio. The zone
design heating air flow rates and loads will be multiplied by
the number input in this field. This input overrides the
building level sizing factor input in the Sizing:Parameters
object. And, of course, if this field is blank or zero, the
global heating sizing factor from the Sizing:Parameters
object is used.
Field: Zone Cooling
Sizing Factor[LINK]
This input is a zone level cooling sizing ratio. The zone
design cooling air flow rates and loads will be multiplied by
the number input in this field. This input overrides the
building level sizing factor input in the Sizing:Parameters
object. And, of course, if this field is blank or zero, the
global cooling sizing factor from the Sizing:Parameters
object is used.
Field: Cooling
Design Air Flow Method[LINK]
The input must be either
Flow/Zone](page-011.html#zone), DesignDay, or
DesignDayWithLimit. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Cooling Design Air Flow Rate as the zone design
cooling air flow rate. DesignDay means the program
will calculate the zone design cooling air flow rate using the
[Sizing:[Zone](#zone) input data and a design day simulation
without imposing any limits other than those set by the
minimum outside air requirements. DesignDayWithLimit
means that the maximum from Cooling Minimum Air Flow per
[Zone](../input-output-reference/page-011.html#zone)
Floor Area and Cooling Minimum Air Flow will set
a lower limit on the **design maximum cooling air flow rate.
The default method is DesignDay: i.e., the program
uses the calculated design values subject to ventilation
requirements.
Field: Cooling
Design Air Flow Rate[LINK]
The design zone cooling air flow rate in cubic meters per
second. This input is used if Cooling Design Air Flow
Method is specified as Flow/Zone. This value
will be multiplied by the global or zone sizing factor and by
zone multipliers.
Field:
Cooling Minimum Air Flow per Zone Floor Area[LINK]
The minimum zone cooling volumetric flow rate per square
meter (units are m3/s-m2). This field is
used when Cooling Design Air Flow Method is specified
as DesignDayWithLimit. In this case it sets a lower
bound on the zone design cooling air flow rate. In all cases
the maximum flow derived from Cooling Minimum Air Flow per
[Zone](../input-output-reference/page-011.html#zone)
Floor Area, Cooling Minimum Air Flow, and
Cooling Minimum Air Flow Fraction is used to set a
minimum supply air flow rate for the zone for VAV systems. The
default is .000762, corresponding to .15 cfm/ft2.
The applicable sizing factor is not applied to this value.
Field: Cooling Minimum
Air Flow[LINK]
The minimum zone cooling volumetric flow rate in
m3/s. This field is used when Cooling Design
Air Flow Method is specified as
DesignDayWithLimit. In this case it sets a lower
bound on the zone design cooling air flow rate. In all cases
the maximum flow derived from Cooling Minimum Air Flow per
[Zone](../input-output-reference/page-011.html#zone)
Floor Area, Cooling Minimum Air Flow, and
Cooling Minimum Air Flow Fraction is used to set a
minimum supply air flow rate for the zone for VAV systems. The
default is zero. The applicable sizing factor is not applied
to this value.
Field:
Cooling Minimum Air Flow Fraction[LINK]
The minimum zone design cooling volumetric flow rate
expressed as a fraction of the zone design cooling volumetric
flow rate. . In all cases the maximum flow derived from
Cooling Minimum Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area, Cooling Minimum Air Flow, and
Cooling Minimum Air Flow Fraction is used to set a
minimum supply air flow rate for the zone for VAV systems. The
default is zero. This input is currently used in sizing the
fan minimum flow rate. It does not currently affect other
component autosizing.
Field: Heating
Design Air Flow Method[LINK]
The input must be either
Flow/Zone](page-011.html#zone), DesignDay, or
DesignDayWithLimit. Flow/[Zone](../input-output-reference/page-011.html#zone)
means that the program will use the input of the field
Heating Design Air Flow Rate as the zone design
heating air flow rate. DesignDay means the program
will calculate the zone design heating air flow rate using the
[Sizing:[Zone](#zone) input data and a design day simulation
without imposing any limits other than those set by the
minimum outside air requirements. DesignDayWithLimit
means that the maximum from Heating Maximum Air Flow per
[Zone](../input-output-reference/page-011.html#zone)
Floor Area and Heating Maximum Air Flow will set
a lower limit on the **design maximum heating air flow rate.
The default method is DesignDay: i.e., the program
uses the calculated design values subject to ventilation
requirements.
Field: Heating
Design Air Flow Rate[LINK]
The design zone heating air flow rate in cubic meters per
second. This input is used if Heating Design Air Flow
Method is specified as Flow/Zone. This value
will be multiplied by the global or zone sizing factor and by
zone multipliers.
Field:
Heating Maximum Air Flow per Zone Floor Area[LINK]
The maximum zone heating volumetric flow rate per square
meter (units are m3/s-m2). This field is
used when Heating Design Air Flow Method is specified
as DesignDayWithLimit. In this case it sets an upper
bound on the zone design heating air flow rate. For this and
the next two input fields, the maximum flow derived from
Heating Maximum Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area, Heating Maximum Air Flow, and
Heating Maximum Air Flow Fraction is used to set a
maximum heating supply air flow rate for the zone for VAV
systems. The default is .002032, corresponding to .40
cfm/ft2. If the maximum heating design flow rate
calculated using these input fields is greater than the design
heating flow rate calculated during sizing, these input fields
have no impact on sizing. It may be more appropriate to select
only one of these three fields to calculate the maximum
heating design flow rate (i.e., if one ore more of these three
fields is 0, it will not be used in calculating the maximum
heating design flow rate).
Field: Heating Maximum
Air Flow[LINK]
The maximum zone heating volumetric flow rate in
m3/s. This field is used when Heating Design
Air Flow Method is specified as
DesignDayWithLimit. In this case it sets an upper
bound on the zone design heating air flow rate. For this field
and the two input fields just prior to and after this
field,,the maximum flow derived from Heating Maximum Air
Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area, Heating Maximum Air Flow, and
Heating Maximum Air Flow Fraction is used to set a
maximum heating supply air flow rate for the zone for VAV
systems. The default is .1415762, corresponding to 300 cfm. If
the maximum heating design flow rate calculated using these
input fields is greater than the design heating flow rate
calculated during sizing, these input fields have no impact on
sizing. It may be more appropriate to select only one of these
three fields to calculate the maximum heating design flow rate
(i.e., if one ore more of these three fields is 0, it will not
be used in calculating the maximum heating design flow
rate).
Field:
Heating Maximum Air Flow Fraction[LINK]
The maximum zone design heating volumetric flow rate
expressed as a fraction of the zone design cooling volumetric
flow rate. For this and the previous two input fields, the
maximum flow derived from Heating Maximum Air Flow per [Zone](../input-output-reference/page-011.html#zone)
Floor Area, Heating Maximum Air Flow, and
Heating Maximum Air Flow Fraction is used to set a
maximum heating supply air flow rate for the zone for VAV
systems. The default is 0.3. If the maximum heating design
flow rate calculated using these input fields is greater than
the design heating flow rate calculated during sizing, these
input fields have no impact on sizing. It may be more
appropriate to select only one of these three fields to
calculate the maximum heating design flow rate (i.e., if one
ore more of these three fields is 0, it will not be used in
calculating the maximum heating design flow rate).
Field:
Design Specification Zone Air Distribution Object
Name[LINK]
The name of the DesignSpecification:ZoneAirDistribution
object, defining the air distribution effectiveness and
secondary recirculation air fraction, that applies to the zone
or zone list. This object may be used for the same zone in the
Controller:MechanicalVentilation](page-051.html#controllermechanicalventilation)
object if no such [DesignSpecification:ZoneAirDistribution
object is specified.
An IDF example:
Sizing:Zone,
SPACE5-1, !- Name of a zone
14., !- Zone cooling design supply air temperature {C}
50., !- Zone heating design supply air temperature {C}
0.009, !- Zone cooling design supply air humidity ratio {kg-H2O/kg-air}
0.004, !- Zone heating design supply air humidity ratio {kg-H2O/kg-air}
DSOA1, !- Design Specification Outdoor Air Object Name
0.0, !- zone heating sizing factor
0.0, !- zone cooling sizing factor
designdaywithlimit, !- Cooling Design Air Flow Method
, !- cooling design air flow rate {m3/s}
, !- Cooling Minimum Air Flow per zone area {m3/s-m2}
, !- Cooling Minimum Air Flow {m3/s}
, !- fraction of the cooling design air flow rate
designday, !- Heating Design Air Flow Method
, !- heating design air flow rate {m3/s}
, !- heating max air flow per zone area {m3/s-m2}
, !- heating max air flow {m3/s}
, !- fraction of the cooling design air flow rate
DSZADO1; !- Design Specification Zone Air Distribution Object Name
DesignSpecification:OutdoorAir,
DSOA1, !- Name
SUM, !- Outdoor Air Method
0.00236, !- Outdoor Air Flow per Person
0.000305, !- Outdoor Air Flow per Zone Floor Area
0.0, !- Outdoor Air Flow per Zone
0.0, !- Outdoor Air Flow Air Changes per Hour
; !- Outdoor Air Flow Rate Fraction Schedule Name
DesignSpecification:ZoneAirDistribution,
DSZADO1, !- Name
1.0, !- Zone Air Distribution Effectiveness in Cooling Mode
1.0, !- Zone Air Distribution Effectiveness in Heating Mode
, !- Zone Air Distribution Effectiveness Schedule Name
0.3; !- Zone Secondary Recirculation Fraction
Zone Sizing Outputs[LINK]
The zone design air flow rates and loads are output onto
the local file “epluszsz.” where is the extension from the
sizing style object (default is csv – a comma separated file
epluszsz.csv). The columns are clearly labeled. It
will easily import into Excel or other spreadsheet program
that accepts delimited files. All of these values are design
air flow rates and loads calculated by the program.
No sizing factors have been applied.
The calculated zone design air flow rates and the user
input or altered zone design air flow rates are also reported
on the eplusout.eio file. The values are printed out
for each zone as comma separated records beginning with Zone
Sizing. Items output on the eio file are: zone
name, load type (heating or cooling), design load, calculated
design air flow rate, user design air flow rate, design day
name, time of peak, outside temperature at peak, outside
humidity ratio at peak.
Sizing:System[LINK]
The Sizing:System
object contains the input needed to perform a central forced
air system design air flow, heating capacity, and cooling
capacity calculation for a system serving one or more zones.
The information needed consists of the outside environmental
conditions and the design supply air temperatures, outdoor air
flow rate, and minimum system air flow ratio.
The outside conditions come from the design days in the
input. A system sizing calculation is performed for every
design day in the input file and the resulting maximum heating
and cooling air flow rates and capacities are saved for use in
the component sizing calculations.
Supply air conditions are specified by inputting a supply
air temperature for cooling, a supply air temperature for
heating, and a preheat temperature.
The system sizing calculation sums the zone design air flow
rates to obtain a system supply air flow rate. The design
conditions and the outdoor air flow rate are used to calculate
a design mixed air temperature. The temperature plus the
design supply air temperatures allows the calculation of
system design heating and cooling capacities.
Field: AirLoop Name[LINK]
The name of the AirLoopHVAC](page-028.html#airloophvac)
corresponding to this [Sizing:System object. This is the air
system for which the design calculation will be made using the
input data of this Sizing:System
Object.
Field: Type of Load to
Size On[LINK]
The user specified type of load on which to size the
central system. The choices are Sensible,
Latent, Total and
VentilationRequirement. Only Sensible and
VentilationRequirement are operational.
Sensible means that the central system supply air
flow rate will be determined by combining the zone design air
flow rates, which have been calculated to meet the zone
sensible loads from the design days.
VentilationRequirement means that the central system
supply air flow rate will be determined by the system
ventilation requirement.
Field: Design
Outdoor Air Flow Rate[LINK]
The design outdoor air flow rate in cubic meters per
second. Generally this should be the minimum outdoor air flow.
It is used for both heating and cooling design calculations.
The assumption for cooling is that any outdoor air economizer
will be closed. If Autosize is input the outdoor air
flow rate will be taken from the sum of the zone outdoor air
flow rates or calculated based on the System Outdoor Air
Method selection (field below).
Field: Minimum
System Air Flow Ratio[LINK]
The design minimum central air flow ratio. This ratio is
the minimum system air flow rate divided by the maximum system
air flow rate. The value must be between 0 and 1. For constant
volume systems the ratio should be set to 1. Note that this
ratio should be set to reflect what the user expects the
system flow rate to be when maximum heating demand occurs.
This ratio is used in calculating the central system heating
capacity. Thus if the system is VAV with the zone VAV dampers
held at minimum flow when there is a zone heating demand, this
ratio should be set to the minimum flow ratio. If the zone VAV
dampers are reverse action and can open to full flow to meet
heating demand, this ratio should be set to 1.
Field: Preheat
Design Temperature[LINK]
The design air temperature exiting the preheat coil (if
any) in degrees Celsius.
Field: Preheat
Design Humidity Ratio[LINK]
The design humidity ratio exiting the preheat coil (if any)
in kilograms of water per kilogram of dry air.
(kgWater/kgDryAir)
Field: Precool
Design Temperature[LINK]
The design air temperature exiting the precooling coil (if
any) in degrees Celsius.
Field: Precool
Design Humidity Ratio[LINK]
The design humidity ratio exiting the precooling coil (if
any) in kilograms of water per kilogram of dry air.
(kgWater/kgDryAir)
Field:
Central Cooling Design Supply Air Temperature[LINK]
The design supply air temperature for cooling in degrees
Celsius. This should be the temperature of the air exiting the
central cooling coil.
Field:
Central Heating Design Supply Air Temperature[LINK]
The design supply air temperature for heating in degrees
Celsius. This can be either the reset temperature for a single
duct system or the actual hot duct supply air temperature for
dual duct systems. It should be the temperature at the exit of
the main heating coil.
Field: Sizing Option[LINK]
If the input is coincident the central system air
flow rate will be sized on the sum of the coincident zone air
flow rates. If the input is noncoincident the central
system air flow rate will be sized on the sum of the
noncoincident zone air flow rates. The default is
noncoincident.
Field: 100% Outdoor
Air in Cooling[LINK]
Entering Yes means the system will be sized for
cooling using 100% outdoor air. Entering No means the
system will be sized for cooling using minimum outside air
(the default).
Field: 100% Outdoor
Air in Heating[LINK]
Entering Yes means the system will be sized for
heating using 100% outdoor air. Entering No means the
system will be sized for heating using minimum outside air
(the default).
Field:
Central Cooling Design Supply Air Humidity Ratio[LINK]
The design humidity ratio in kilograms of water per
kilogram of dry air at the exit of the central cooling coil.
(kgWater/kgDryAir) The default is .008.
Field:
Central Heating Design Supply Air Humidity Ratio[LINK]
The design humidity ratio in kilograms of water per
kilogram of dry air at the exit of the central heating coil.
(kgWater/kgDryAir) The default is .008.
Field: Cooling
Design Air Flow Method[LINK]
The input must be either DesignDay or
Flow/System. DesignDay means the program
will calculate the system design cooling air flow rate using
the System Sizing input data and a design day simulation.
Flow/System means that the program will use the input
of the field Cooling Design Air Flow Rate as the
system design cooling air flow rate. The default method is
DesignDay: i.e., the program uses the calculated
design values.
Field: Cooling
Design Air Flow Rate[LINK]
The design system cooling air flow rate in cubic meters per
second. This input is an alternative to using the program
calculated value. This input is used if Cooling Design Air
Flow Method is Flow/System. This value will not be
multiplied by any sizing factor or by zone multipliers. If
using zone multipliers, this value must be large enough to
serve the multiplied zones.
Field: Heating
Design Air Flow Method[LINK]
The input must be either DesignDay or
Flow/System. DesignDay means the program
will calculate the system design heating air flow rate using
the System Sizing input data and a design day simulation.
Flow/System means that the program will use the input
of the field Heating Design Air Flow Rate as the
system design heating air flow rate. . The default method is
DesignDay: i.e., the program uses the calculated
design values.
Field: Heating
Design Air Flow Rate[LINK]
The design system heating air flow rate in cubic meters per
second. This input is an alternative to using the program
calculated value. This input is used if Heating Design Air
Flow Method is Flow/System. This value will not be
multiplied by any sizing factor or by zone multipliers. If
using zone multipliers, this value must be large enough to
serve the multiplied zones.
Field: System Outdoor
Air Method[LINK]
The method used to calculate the system minimum outdoor air
flow. The two choices are ZoneSum and VentilationRateProcedure
(VRP). ZoneSum sums the outdoor air flows across all zones
served by the system. VRP uses the multi-zone equations
defined in 62.1-2007 to calculate the system outdoor air flow.
VRP considers zone air distribution effectiveness and zone
diversification of outdoor air fractions.
Field: Zone
Maximum Outdoor Air Fraction[LINK]
This positive numeric input is the zone maximum outdoor air
fraction. For an air loop, when a zone requires outdoor air
higher than the user specified [Zone](../input-output-reference/page-011.html#zone)
Maximum Outdoor Air Fraction, the zone supply air flow will be
increased to cap the outdoor air fraction at the maximum
value. This allows the system level outdoor air flow to be
reduced while the total supply air flow increases. Valid
values are from 0 to 1.0. Default is 1.0 which indicates zones
can have 100% outdoor air maintaining backward compatibility.
This inputs work for constant volume air systems, single and
dual duct VAV systems.
An IDF example:
Sizing:System,
VAV Sys 1, !- name of an AirLoopHVAC object
sensible, !- type of load to size on
autosize, !- Design (minimum) outside air volumetric flow rate {m3/s}
0.3, !- minimum system air flow ratio
4.5, !- Preheat design temperature {C}
.008, !- Preheat design humidity ratio {kgWater/kgDryAir}
11.0, !- Precool design temperature {C}
.008, !- Precool design humidity ratio {kgWater/kgDryAir}
12.8, !- Central cooling design supply air temperature {C}
16.7, !- Central heating design supply air temperature {C}
noncoincident, !- Sizing Option
no, !- Cooling 100% Outside Air
no, !- Heating 100% Outside Air
0.008, !- Central cooling design supply air humidity ratio {kgWater/kgDryAir}
0.008, !- Central heating design supply air humidity ratio {kgWater/kgDryAir}
designday, !- Cooling Design Air Flow Method
0, !- cooling design air flow rate {m3/s}
designday, !- Heating Design Air Flow Method
0, !- heating design air flow rate {m3/s}
ZoneSum, !- System Outdoor Air Method
0.5; !- Zone Maximum Outdoor Air Fraction
System Sizing Outputs[LINK]
The system design air flow rates and heating and cooling
capacities are output onto the local file “eplusssz.” where is
the extension from the sizing style object (default is csv – a
comma separated file eplusssz.csv). The columns are
clearly labeled. It will easily import into Excel or other
spreadsheet program that accepts delimited files. The results
are calculated values and do not include any user input system
flow rates.
The calculated system design air flow rates and the user
input system design air flow rates are also reported on the
eplusout.eio file. The values are printed out for
each system as comma separated records beginning with
System Sizing. An example is:
! <System Sizing Information>, System Name, Field Description, Value
System Sizing, VAV SYS 1, Calculated Cooling Design Air Flow Rate [m3/s], 1.3194
System Sizing, VAV SYS 1, User Cooling Design Air Flow Rate [m3/s], 1.5000
System Sizing, VAV SYS 1, Calculated Heating Design Air Flow Rate [m3/s], 0.90363
System Sizing, VAV SYS 1, User Heating Design Air Flow Rate [m3/s], 1.0000
The Sizing:Plant
object contains the input needed for the program to calculate
plant loop flow rates and equipment capacities when
autosizing. This information is initially used by components
that use water for heating or cooling such as hot or chilled
water coils to calculate their maximum water flow rates. These
flow rates are then summed for use in calculating the Plant
Loop flow rates.
The program will size any number of chilled water, hot
water, condenser water and other plant loops. There should be
one Sizing:Plant
object for each plant loop that is to be autosized.
Field: Plant or
Condenser Loop Name[LINK]
The name of a Plant Loop or Condenser Loop object
corresponding to this Sizing:Plant
object. This is the plant loop for which this data will be
used for calculating the loop flow rate.
Field: Loop Type[LINK]
The possible inputs are Heating, Steam, Cooling,
or Condenser.
Field: Design Loop
Exit Temperature[LINK]
The water temperature in degrees Celsius at the exit of the
supply side of the plant loop, Thus this is the temperature of
the water supplied to the inlet of chilled or hot water coils
and other equipment that places loads on a plant loop.
Field: Loop
Design Temperature Difference[LINK]
The design temperature rise (for cooling or condenser
loops) or fall (for heating loops) in degrees Celsius across
the demand side of a plant loop. This temperature difference
is used by component models to determine flow rates required
to meet design capacities. Larger values lead to smaller
design flow rates.
An IDF example:
Sizing:Plant,
Chilled Water Loop, ! name of loop
Cooling, ! type of loop
7.22, ! chilled water supply temperature
6.67; ! chilled water delta T
Plant Sizing Outputs[LINK]
The loop flow rates are reported on the
eplusout.eio file along with the component sizing
results.
Group – Design Objects[LINK]
Input for Design Calculations and Component Autosizing[LINK]
Overview[LINK]
In order for EnergyPlus to successfully calculate zone design heating and cooling loads and air flow rates and for the program to use these results to automatically size the HVAC components a number of input objects must be present and certain object input fields must be entered.
The input file should contain a SimulationControl object. The 1st field Do [Zone](../input-output-reference/page-011.html#zone) Sizing Calculation should be entered as Yes. This will cause a zone sizing simulation to be done using all the sizing periods in the input file as weather. If there are no air or water loops in the HVAC input fields 2 and 3 can be set to No. If there are one or more air loops (i.e., there is at least one [AirLoopHVAC](../input-output-reference/page-028.html#airloophvac) object in the input file) then the 2nd field Do System Sizing Calculation should be entered as Yes. If there are one or more water loops (Plant Loop objects) then the 3rd field Do Plant Sizing Calculation should be set to Yes. Finally either the 4th field (Run Simulation for Sizing Periods) or the 5th field (Run Simulation for Weather File Run Periods) should be set to Yes in order to autosize the components and do a real simulation using the autosized components. The component autosizing calculations are done on the first pass through the HVAC system in the real simulation.
There must be at least 2 (up to any number) SizingPeriod objects present. Normally one will be for summer conditions and one for winter. The summer day should normally have the field Day Type set to SummerDesignDay. The winter design day should normally have Day Type set to WinterDesignDay.
To apply a global sizing factor include the Sizing:Parameters object.
For each controlled zone in the input file there should be a corresponding Sizing:Zone](page-011.html#zone) object. Similarly for each [AirLoopHVAC](../input-output-reference/page-028.html#airloophvac) there should be a [Sizing:System object. And for each Plant or Condenser Loop there should be a Sizing:Plant object. Note however that if a controlled zone has no corresponding [Zone](../input-output-reference/page-011.html#zone) Sizing object the data from the first [Zone](../input-output-reference/page-011.html#zone) Sizing object will be used. Thus if all the zone sizing information is the same only one [Zone](../input-output-reference/page-011.html#zone) Sizing object need be entered.
Only controlled zones are included in the zone and system sizing calculations. Thus for a design air flow rate to be calculated for a zone, it must contain a thermostat even though it might not need or have a thermostat in the full simulation. An illustration would be a three zone building with a packaged single zone system and a thermostat in one of the zones. In order for the two slave zones to be included in the design air flow calculations they must be treated as if they have a thermostat: there must be a [ZoneControl:Thermostat](../input-output-reference/page-037.html#zonecontrolthermostat) for each of the slave zones.
Some attention should be paid to schedules. In a weekly schedule object the 9th and 10th day schedules are for summer and winter design days respectively. This means that if a SizingPeriod object has field Day Type set to SummerDesignDay the day schedule for summer sizing periods will be in effect. Similarly if a SizingPeriod object has field Day Type set to WinterDesignDay the day schedule for winter sizing periods will be in effect. Some possible applications of this capability are:
None of these applications are necessarily recommended but these and other uses of the special summer/winter design day schedules may prove useful for specific situations.
Component Autosizing[LINK]
For autosizing to occur at the component level the user must enter the special value autosize in the numeric fields for which autosizing is available. Those fields can be found by looking at the Energy+.idd data dictionary file or under individual object details in this document. Fields that can be autosized are denoted with the comment \autosizable. The components and fields that are autosizable are listed in the following table. Note that spaces may be inserted in object names to facilitate readability.
Table: Details of Autosizable Objects/Fields
Component / Object Name|Autosizable Fields ———————–|—————— AirConditioner:VariableRefrigerantFlow |Gross Rated Total Cooling Capacity |Gross Rated Heating Capacity |Resistive Defrost Heater Capacity |Water Condenser Volume Flow Rate |Evaporative Condenser Air Flow Rate |Evaporative Condenser Pump Rated Power Consumption AirLoopHVAC |Design Supply Air Flow Rate AirLoopHVAC:Unitary:Furnace:HeatCool |Maximum Supply Air Temperature |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Cooling or Heating is Needed AirLoopHVAC:Unitary:Furnace:HeatOnly |Maximum Supply Air Temperature |Supply Air Flow Rate AirLoopHVAC:UnitaryHeatCool |Maximum Supply Air Temperature |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Cooling or Heating is Needed AirLoopHVAC:UnitaryHeatCool:VAVChangeoverBypass |System Air Flow Rate During Cooling Operation |System Air Flow Rate During Heating Operation |System Air Flow Rate When No Cooling or Heating is Needed |Outdoor Air Flow Rate During Cooling Operation |Outdoor Air Flow Rate During Heating Operation |Outdoor Air Flow Rate When No Cooling or Heating is Needed AirLoopHVAC:UnitaryHeatOnly |Maximum Supply Air Temperature |Supply Air Flow Rate AirLoopHVAC:UnitaryHeatPump:AirToAir |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Cooling or Heating is Needed |Maximum Supply Air Temperature from Supplemental Heater AirLoopHVAC:UnitaryHeatPump:AirToAir:MultiSpeed |Maximum Supply Air Temperature from Supplemental Heater |Supply Air Flow Rate When No Cooling or Heating is Needed |Speed 1 Supply Air Flow Rate During Heating Operation |Speed 2 Supply Air Flow Rate During Heating Operation |Speed 3 Supply Air Flow Rate During Heating Operation |Speed 4 Supply Air Flow Rate During Heating Operation |Speed 1 Supply Air Flow Rate During Cooling Operation |Speed 2 Supply Air Flow Rate During Cooling Operation |Speed 3 Supply Air Flow Rate During Cooling Operation |Speed 4 Supply Air Flow Rate During Cooling Operation AirLoopHVAC:UnitaryHeatPump:WaterToAir |Supply Air Flow Rate |Maximum Supply Air Temperature from Supplemental Heater AirLoopHVAC:UnitarySystem |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Cooling or Heating is Required |Maximum Supply Air Temperature AirTerminal:DualDuct:ConstantVolume |Maximum Air Flow Rate AirTerminal:DualDuct:VAV |Maximum Damper Air Flow Rate AirTerminal:DualDuct:VAV:OutdoorAir |Maximum Terminal Air Flow Rate AirTerminal:SingleDuct:ConstantVolume:CooledBeam |Supply Air Volumetric Flow Rate |Maximum Total Chilled Water Volumetric Flow Rate |Number of Beams |Beam Length AirTerminal:SingleDuct:ConstantVolume:FourPipeInduction |Maximum Total Air Flow Rate |Maximum Hot Water Flow Rate |Maximum Cold Water Flow Rate AirTerminal:SingleDuct:ConstantVolume:Reheat |Maximum Air Flow Rate |Maximum Hot Water or Steam Flow Rate AirTerminal:SingleDuct:ParallelPIU:Reheat |Maximum Primary Air Flow Rate |Maximum Secondary Air Flow Rate |Minimum Primary Air Flow Fraction |Fan On Flow Fraction |Maximum Hot Water or Steam Flow Rate AirTerminal:SingleDuct:SeriesPIU:Reheat |Maximum Air Flow Rate |Maximum Primary Air Flow Rate |Minimum Primary Air Flow Fraction |Maximum Hot Water or Steam Flow Rate AirTerminal:SingleDuct:Uncontrolled |Maximum Air Flow Rate AirTerminal:SingleDuct:VAV:HeatAndCool:NoReheat |Maximum Air Flow Rate AirTerminal:SingleDuct:VAV:HeatAndCool:Reheat |Maximum Air Flow Rate |Maximum Hot Water or Steam Flow Rate AirTerminal:SingleDuct:VAV:NoReheat |Maximum Air Flow Rate AirTerminal:SingleDuct:VAV:Reheat |Maximum Air Flow Rate |Maximum Hot Water or Steam Flow Rate AirTerminal:SingleDuct:VAV:Reheat:VariableSpeedFan |Maximum Cooling Air Flow Rate |Maximum Heating Air Flow Rate |Maximum Hot Water or Steam Flow Rate Boiler:HotWater |Nominal Capacity |Design Water Flow Rate Boiler:Steam |Nominal Capacity Branch |Maximum Flow Rate Chiller:Absorption |Nominal Capacity |Nominal Pumping Power |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate |Design Generator Fluid Flow Rate Chiller:Absorption:Indirect |Nominal Capacity |Nominal Pumping Power |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate |Design Generator Fluid Flow Rate Chiller:CombustionTurbine |Nominal Capacity |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate |Gas Turbine Engine Capacity Chiller:ConstantCOP |Nominal Capacity |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate Chiller:Electric |Nominal Capacity |Design Chilled Water Flow Rate |Design Condenser Fluid Flow Rate |Design Heat Recovery Water Flow Rate Chiller:Electric:EIR |Reference Capacity |Reference Chilled Water Flow Rate |Reference Condenser Fluid Flow Rate |Design Heat Recovery Water Flow Rate Chiller:Electric:ReformulatedEIR |Reference Capacity |Reference Chilled Water Flow Rate |Reference Condenser Water Flow Rate |Design Heat Recovery Water Flow Rate Chiller:EngineDriven |Nominal Capacity |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate ChillerHeater:Absorption:DirectFired |Nominal Cooling Capacity |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate |Design Hot Water Flow Rate ChillerHeater:Absorption:DoubleEffect |Nominal Cooling Capacity |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate |Design Hot Water Flow Rate ChillerHeaterPerformance:Electric:EIR |Reference Cooling Mode Evaporator Capacity |Design Chilled Water Flow Rate |Design Condenser Water Flow Rate Coil:Cooling:DX:MultiSpeed |Speed 1 Gross Rated Total Cooling Capacity |Speed 1 Gross Rated Sensible Heat Ratio |Speed 1 Rated Air Flow Rate |Speed 1 Evaporative Condenser Air Flow Rate |Speed 1 Rated Evaporative Condenser Pump Power Consumption |Speed 2 Gross Rated Total Cooling Capacity |Speed 2 Gross Rated Sensible Heat Ratio |Speed 2 Rated Air Flow Rate |Speed 2 Evaporative Condenser Air Flow Rate |Speed 2 Rated Evaporative Condenser Pump Power Consumption |Speed 3 Gross Rated Total Cooling Capacity |Speed 3 Gross Rated Sensible Heat Ratio |Speed 3 Rated Air Flow Rate |Speed 3 Evaporative Condenser Air Flow Rate |Speed 3 Rated Evaporative Condenser Pump Power Consumption |Speed 4 Gross Rated Total Cooling Capacity |Speed 4 Gross Rated Sensible Heat Ratio |Speed 4 Rated Air Flow Rate |Speed 4 Evaporative Condenser Air Flow Rate |Speed 4 Rated Evaporative Condenser Pump Power Consumption Coil:Cooling:DX:SingleSpeed |Gross Rated Total Cooling Capacity |Gross Rated Sensible Heat Ratio |Rated Air Flow Rate |Evaporative Condenser Air Flow Rate |Evaporative Condenser Pump Rated Power Consumption Coil:Cooling:DX:SingleSpeed:ThermalStorage |Rated Evaporator Air Flow Rate |Cooling Only Mode Rated Total Evaporator Cooling Capacity |Evaporative Condenser Pump Rated Power Consumption Coil:Cooling:DX:TwoSpeed |High Speed Gross Rated Total Cooling Capacity |High Speed Rated Sensible Heat Ratio |High Speed Rated Air Flow Rate |Low Speed Gross Rated Total Cooling Capacity |Low Speed Gross Rated Sensible Heat Ratio |Low Speed Rated Air Flow Rate |High Speed Evaporative Condenser Air Flow Rate |High Speed Evaporative Condenser Pump Rated Power Consumption |Low Speed Evaporative Condenser Air Flow Rate |Low Speed Evaporative Condenser Pump Rated Power Consumption Coil:Cooling:DX:VariableRefrigerantFlow |Gross Rated Total Cooling Capacity |Gross Rated Sensible Heat Ratio |Rated Air Flow Rate Coil:Cooling:DX:VariableSpeed |Gross Rated Total Cooling Capacity At Selected Nominal Speed Level |Rated Air Flow Rate At Selected Nominal Speed Level |Evaporative Condenser Pump Rated Power Consumption Coil:Cooling:Water |Design Water Flow Rate |Design Air Flow Rate |Design Inlet Water Temperature |Design Inlet Air Temperature |Design Outlet Air Temperature |Design Inlet Air Humidity Ratio |Design Outlet Air Humidity Ratio Coil:Cooling:Water:DetailedGeometry |Maximum Water Flow Rate |Tube Outside Surface Area |Total Tube Inside Area |Fin Surface Area |Minimum Airflow Area |Coil Depth |Fin Diameter |Number of Tubes per Row Coil:Cooling:WaterToAirHeatPump:EquationFit |Rated Air Flow Rate |Rated Water Flow Rate |Gross Rated Total Cooling Capacity |Gross Rated Sensible Cooling Capacity Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit |Gross Rated Total Cooling Capacity At Selected Nominal Speed Level |Rated Air Flow Rate At Selected Nominal Speed Level |Rated Water Flow Rate At Selected Nominal Speed Level Coil:Heating:DX:MultiSpeed |Resistive Defrost Heater Capacity |Speed 1 Gross Rated Heating Capacity |Speed 1 Rated Air Flow Rate |Speed 2 Gross Rated Heating Capacity |Speed 2 Rated Air Flow Rate |Speed 3 Gross Rated Heating Capacity |Speed 3 Rated Air Flow Rate |Speed 4 Gross Rated Heating Capacity |Speed 4 Rated Air Flow Rate Coil:Heating:DX:SingleSpeed |Gross Rated Heating Capacity |Rated Air Flow Rate |Resistive Defrost Heater Capacity Coil:Heating:DX:VariableRefrigerantFlow |Gross Rated Heating Capacity |Rated Air Flow Rate Coil:Heating:DX:VariableSpeed |Rated Heating Capacity At Selected Nominal Speed Level |Rated Air Flow Rate At Selected Nominal Speed Level |Resistive Defrost Heater Capacity Coil:Heating:Electric |Nominal Capacity Coil:Heating:Electric:MultiStage |Stage 1 Nominal Capacity |Stage 2 Nominal Capacity |Stage 3 Nominal Capacity |Stage 4 Nominal Capacity Coil:Heating:Gas |Nominal Capacity Coil:Heating:Gas:MultiStage |Stage 1 Nominal Capacity |Stage 2 Nominal Capacity |Stage 3 Nominal Capacity |Stage 4 Nominal Capacity Coil:Heating:Steam |Maximum Steam Flow Rate Coil:Heating:Water |U-Factor Times Area Value |Maximum Water Flow Rate |Rated Capacity Coil:Heating:WaterToAirHeatPump:EquationFit |Rated Air Flow Rate |Rated Water Flow Rate |Gross Rated Heating Capacity Coil:Heating:WaterToAirHeatPump:VariableSpeedEquationFit |Rated Heating Capacity At Selected Nominal Speed Level |Rated Air Flow Rate At Selected Nominal Speed Level |Rated Water Flow Rate At Selected Nominal Speed Level CoilPerformance:DX:Cooling |Gross Rated Total Cooling Capacity |Gross Rated Sensible Heat Ratio |Rated Air Flow Rate |Evaporative Condenser Air Flow Rate |Evaporative Condenser Pump Rated Power Consumption CondenserLoop |Maximum Loop Flow Rate Controller:OutdoorAir |Minimum Outdoor Air Flow Rate |Maximum Outdoor Air Flow Rate Controller:WaterCoil |Controller Convergence Tolerance |Maximum Actuated Flow CoolingTower:SingleSpeed |Design Water Flow Rate |Design Air Flow Rate |Design Fan Power |Design U-Factor Times Area Value CoolingTower:TwoSpeed |Design Water Flow Rate |High Fan Speed Air Flow Rate |High Fan Speed Fan Power |High Fan Speed U-Factor Times Area Value CoolingTower:VariableSpeed |Design Water Flow Rate |Design Air Flow Rate |Design Fan Power CoolingTower:VariableSpeed:Merkel |Nominal Capacity |Design Water Flow Rate |Design Air Flow Rate U-Factor Times Area Value EvaporativeCooler:Indirect:ResearchSpecial |Secondary Fan Flow Rate EvaporativeFluidCooler:SingleSpeed |Design Air Flow Rate |Design Air Flow Rate Fan Power |Design Air Flow Rate U-factor Times Area Value |Design Water Flow Rate EvaporativeFluidCooler:TwoSpeed |High Fan Speed Air Flow Rate |High Fan Speed Fan Power |High Fan Speed U-factor Times Area Value |Design Water Flow Rate Fan:ComponentModel |Maximum Flow Rate |Minimum Flow Rate |Motor Fan Pulley Ratio |Belt Maximum Torque |Maximum Motor Output Power |Maximum VFD Output Power Fan:ConstantVolume |Maximum Flow Rate Fan:OnOff |Maximum Flow Rate FanPerformance:NightVentilation |Maximum Flow Rate Fan:VariableVolume |Maximum Flow Rate FluidCooler:SingleSpeed |Design Air Flow Rate U-factor Times Area Value |Design Water Flow Rate |Design Air Flow Rate |Design Air Flow Rate Fan Power FluidCooler:TwoSpeed |High Fan Speed U-factor Times Area Value |Design Water Flow Rate |High Fan Speed Air Flow Rate |High Fan Speed Fan Power HeaderedPumps:ConstantSpeed |Total Rated Flow Rate |Rated Power Consumption HeaderedPumps:VariableSpeed |Total Rated Flow Rate |Rated Power Consumption HeatExchanger:AirToAir:SensibleAndLatent |Nominal Supply Air Flow Rate HeatExchanger:FluidToFluid |Loop Demand Side Design Flow Rate |Loop Supply Side Design Flow Rate |Heat Exchanger U-Factor Times Area Value Humidifier:Steam:Electric |Rated Power HVACTemplate:Plant:Boiler |Capacity HVACTemplate:Plant:Chiller |Capacity HVACTemplate:Plant:Tower |High Speed Nominal Capacity |High Speed Fan Power |Low Speed Nominal Capacity |Low Speed Fan Power |Free Convection Capacity HVACTemplate:System:ConstantVolume |Supply Fan Maximum Flow Rate |Heating Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:DedicatedOutdoorAir |Supply Fan Flow Rate |DX Cooling Coil Gross Rated Total Capacity |DX Cooling Coil Gross Rated Sensible Heat Ratio |Humidifier Rated Electric Power HVACTemplate:System:DualDuct |Main Supply Fan Maximum Flow Rate |Cold [Duct](../input-output-reference/page-021.html#duct) Supply Fan Maximum Flow Rate |Hot [Duct](../input-output-reference/page-021.html#duct) Supply Fan Maximum Flow Rate |Heating Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:PackagedVAV |Supply Fan Maximum Flow Rate |Supply Fan Minimum Flow Rate |Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heating Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:Unitary |Supply Fan Maximum Flow Rate |Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heating Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:UnitaryHeatPump:AirToAir |Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate |No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heat Pump Heating Coil Gross Rated Capacity |Supplemental Heating Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:UnitarySystem |Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate |No Load Supply Air Flow Rate |DX Cooling Coil Gross Rated Total Capacity |DX Cooling Coil Gross Rated Sensible Heat Ratio |Heating Coil Gross Rated Capacity |Supplemental Heating or Reheat Coil Capacity |Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:VAV |Supply Fan Maximum Flow Rate |Supply Fan Minimum Flow Rate |Maximum Outdoor Air Flow Rate |Minimum Outdoor Air Flow Rate |Humidifier Rated Electric Power HVACTemplate:System:VRF |Gross Rated Total Cooling Capacity |Gross Rated Heating Capacity |Resistive Defrost Heater Capacity |Water Condenser Volume Flow Rate |Evaporative Condenser Air Flow Rate |Evaporative Condenser Pump Rated Power Consumption HVACTemplate:Zone:BaseboardHeat |Baseboard Heating Capacity HVACTemplate:Zone:ConstantVolume |Supply Air Maximum Flow Rate |Baseboard Heating Capacity HVACTemplate:Zone:DualDuct |Supply Air Maximum Flow Rate |Baseboard Heating Capacity HVACTemplate:Zone:FanCoil |Supply Air Maximum Flow Rate |Baseboard Heating Capacity HVACTemplate:Zone:IdealLoadsAirSystem |Maximum Heating Air Flow Rate |Maximum Sensible Heating Capacity |Maximum Cooling Air Flow Rate |Maximum Total Cooling Capacity HVACTemplate:Zone:PTAC |Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate |No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heating Coil Capacity |Baseboard Heating Capacity HVACTemplate:Zone:PTHP |Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate |No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heat Pump Heating Coil Gross Rated Capacity |Supplemental Heating Coil Capacity |Baseboard Heating Capacity HVACTemplate:Zone:Unitary |Supply Air Maximum Flow Rate |Baseboard Heating Capacity HVACTemplate:Zone:VAV |Supply Air Maximum Flow Rate |Baseboard Heating Capacity HVACTemplate:Zone:VAV:FanPowered |Primary Supply Air Maximum Flow Rate |Primary Supply Air Minimum Flow Fraction |Secondary Supply Air Maximum Flow Rate |Parallel Fan On Flow Fraction |Baseboard Heating Capacity HVACTemplate:Zone:VAV:HeatAndCool |Supply Air Maximum Flow Rate |Baseboard Heating Capacity HVACTemplate:Zone:VRF |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate When No Cooling is Needed |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Heating is Needed |Outdoor Air Flow Rate During Cooling Operation |Outdoor Air Flow Rate During Heating Operation |Outdoor Air Flow Rate When No Cooling or Heating is Needed |Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heat Pump Heating Coil Gross Rated Capacity |Baseboard Heating Capacity HVACTemplate:Zone:WaterToAirHeatPump |Cooling Supply Air Flow Rate |Heating Supply Air Flow Rate |No Load Supply Air Flow Rate |Cooling Coil Gross Rated Total Capacity |Cooling Coil Gross Rated Sensible Heat Ratio |Heat Pump Heating Coil Gross Rated Capacity |Supplemental Heating Coil Capacity |Baseboard Heating Capacity PlantComponent:TemperatureSource |Design Volume Flow Rate PlantEquipmentOperation:ComponentSetpoint |Component 1 Flow Rate |Component 2 Flow Rate |Component 3 Flow Rate |Component 4 Flow Rate |Component 5 Flow Rate |Component 6 Flow Rate |Component 7 Flow Rate |Component 8 Flow Rate |Component 9 Flow Rate |Component 10 Flow Rate PlantLoop |Maximum Loop Flow Rate Pump:ConstantSpeed |Rated Flow Rate |Rated Power Consumption Pump:VariableSpeed |Rated Flow Rate |Rated Power Consumption Pump:VariableSpeed:Condensate |Rated Flow Rate |Rated Power Consumption Sizing:System |Design Outdoor Air Flow Rate SolarCollector:FlatPlate:PhotovoltaicThermal |Design Flow Rate ThermalStorage:ChilledWater:Mixed |Use Side Design Flow Rate |Source Side Design Flow Rate ThermalStorage:ChilledWater:Stratified |Use Side Design Flow Rate |Source Side Design Flow Rate UnitarySystemPerformance:HeatPump:Multispeed |Speed 1 Supply Air Flow Ratio During Heating Operation |Speed 1 Supply Air Flow Ratio During Cooling Operation |Speed 2 Supply Air Flow Ratio During Heating Operation |Speed 2 Supply Air Flow Ratio During Cooling Operation |Speed 3 Supply Air Flow Ratio During Heating Operation |Speed 3 Supply Air Flow Ratio During Cooling Operation |Speed 4 Supply Air Flow Ratio During Heating Operation |Speed 4 Supply Air Flow Ratio During Cooling Operation WaterHeater:Mixed |Tank Volume |Heater Maximum Capacity |Use Side Design Flow Rate |Source Side Design Flow Rate WaterHeater:Stratified |Tank Volume |Tank Height |Heater 1 Capacity |Use Side Design Flow Rate |Source Side Design Flow Rate ZoneHVAC:Baseboard:Convective:Electric |Nominal Capacity ZoneHVAC:Baseboard:Convective:Water |U-Factor Times Area Value |Maximum Water Flow Rate ZoneHVAC:Baseboard:RadiantConvective:Electric |Nominal Capacity ZoneHVAC:Baseboard:RadiantConvective:Steam |Maximum Steam Flow Rate ZoneHVAC:Baseboard:RadiantConvective:Water |Rated Capacity |Maximum Water Flow Rate ZoneHVAC:EnergyRecoveryVentilator |Supply Air Flow Rate |Exhaust Air Flow Rate ZoneHVAC:EvaporativeCoolerUnit |Design Supply Air Flow Rate ZoneHVAC:FourPipeFanCoil |Maximum Supply Air Flow Rate |Maximum Outdoor Air Flow Rate |Maximum Cold Water Flow Rate |Maximum Hot Water Flow Rate ZoneHVAC:HighTemperatureRadiant |Maximum Power Input ZoneHVAC:IdealLoadsAirSystem |Maximum Heating Air Flow Rate |Maximum Sensible Heating Capacity |Maximum Cooling Air Flow Rate |Maximum Total Cooling Capacity ZoneHVAC:LowTemperatureRadiant:Electric |Maximum Electrical Power to Panel ZoneHVAC:LowTemperatureRadiant:VariableFlow |Hydronic Tubing Length |Maximum Hot Water Flow |Maximum Cold Water Flow ZoneHVAC:OutdoorAirUnit |Outdoor Air Flow Rate |Exhaust Air Flow Rate ZoneHVAC:PackagedTerminalAirConditioner |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Cooling or Heating is Needed |Outdoor Air Flow Rate During Cooling Operation |Outdoor Air Flow Rate During Heating Operation |Outdoor Air Flow Rate When No Cooling or Heating is Needed ZoneHVAC:PackagedTerminalHeatPump |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Cooling or Heating is Needed |Outdoor Air Flow Rate During Cooling Operation |Outdoor Air Flow Rate During Heating Operation |Outdoor Air Flow Rate When No Cooling or Heating is Needed |Maximum Supply Air Temperature from Supplemental Heater ZoneHVAC:TerminalUnit:VariableRefrigerantFlow |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate When No Cooling is Needed |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Heating is Needed |Outdoor Air Flow Rate During Cooling Operation |Outdoor Air Flow Rate During Heating Operation |Outdoor Air Flow Rate When No Cooling or Heating is Needed ZoneHVAC:UnitHeater |Maximum Supply Air Flow Rate |Maximum Hot Water or Steam Flow Rate ZoneHVAC:UnitVentilator |Maximum Supply Air Flow Rate |Minimum Outdoor Air Flow Rate |Maximum Outdoor Air Flow Rate ZoneHVAC:VentilatedSlab |Maximum Air Flow Rate |Minimum Outdoor Air Flow Rate |Maximum Outdoor Air Flow Rate ZoneHVAC:WaterToAirHeatPump |Supply Air Flow Rate During Cooling Operation |Supply Air Flow Rate During Heating Operation |Supply Air Flow Rate When No Cooling or Heating is Needed |Outdoor Air Flow Rate During Cooling Operation |Outdoor Air Flow Rate During Heating Operation |Outdoor Air Flow Rate When No Cooling or Heating is Needed |Maximum Supply Air Temperature from Supplemental Heater ZoneHVAC:WindowAirConditioner |Maximum Supply Air Flow Rate |Maximum Outdoor Air Flow Rate
There are 3 places in the input where the user can impose sizing factors.
In Sizing Parameters (object: Sizing:Parameters), the user can specify an over-all sizing factor. This factor is applied to all the zone design loads and air flow rates resulting from the zone sizing calculations.
In [Zone](../input-output-reference/page-011.html#zone) Sizing (object: Sizing:[Zone](../input-output-reference/page-011.html#zone)), the user can specify a sizing factor for a specific zone. The factor is applied to the calculated zone design loads and air flow rates for the zone named in the Sizing:[Zone](../input-output-reference/page-011.html#zone) object. This sizing factor overrides the global sizing factor. That is, a zone sizing factor, if specified, replaces the global sizing factor for the named zone.
For some plant components (basically all central chillers, boilers and cooling towers) the user can specify a sizing factor that modifies the autosized component capacity and flow rates. These factors are applied after the application of global or zone sizing factors. They are primarily used to split the design load between multiple components. These sizing factors can change the autosizing of the associated loops and pumps. The following rules are followed the effect of plant component sizing factors on loops and pumps.
For supply side branches, the sizing factors of all components in series on the branch are summed and the result becomes the branch sizing factor. If there is a branch pump its autosized design flow rate is multiplied by the branch sizing factor.
For each loop, if the average of the branch sizing factors is less than 1, the loop sizing factor is set equal to the sum of the branch sizing factors. If the average is greater than 1, the loop sizing factor is set equal to the maximum of the branch sizing factors. The loop sizing factor is applied to the loop design flow rate (if autosized) and to the loop pump flow rate (if autosized).
Mixing User-Specified and Autosized Inputs[LINK]
Mixed user-specified and autosized inputs can be successfully used if the following points and suggestions are followed.
Each component is autosized independently. Thus user input for a flow rate in one component will have no effect on other components’ autosized flow rates. For instance, specifying the chilled water loop pump’s rated flow rate will have no effect on the autosizing of the chiller’s design evaporator flow rate or on the plant loop’s autosized maximum loop flow rate.
Within a component it is best to autosize all inputs are enter specified values for all inputs. For example, in a chiller, if only the nominal capaciity is user-specified, the autosized chilled water flow rate may not be consistent with the specified capacity.
Sizing information flows only from the sizing objects to the components. The sizing calculations have no knowledge of user-specified values in a component. The only exception to this rule is that plant loop sizing will collect all component design water flow rates whether autosized or user-specified.
If the user wants to specify a zone or system air flow rate it should be done using the Sizing:Zone and Sizing:System objects rather than done in the individual components.
The plant loop flow rates are sized from the total design demand of the components connected to each loop. The components demanding water need not be autosized for the plant loop autosizing to work successfully. So the user could specify all the air side components and autosize all the plant loops and plant components. Or specify the chilled water loop flow rate, chilled water pump inputs and chiller inputs and let the condenser loop and tower autosize.
Component Sizing Output[LINK]
The results of the component autosizing calculations are reported on the eplusout.eio file. For each component field that has been autosized the object type, object name, field description with unit, and value are printed out as comma separated data on a line beginning with Component Sizing. Examples of this are shown in the Output Details and Examples document.
The complete list of objects that have autosized fields is shown in the following table. Note that spaces may be inserted in object names to facilitate readability.
Table: Complete list of Objects with autosized Fields
Object Name|Object Name ———–|———– AirConditioner:VariableRefrigerantFlow|AirLoopHVAC AirLoopHVAC:Unitary:Furnace:HeatCool|AirLoopHVAC:Unitary:Furnace:HeatOnly AirLoopHVAC:UnitaryHeatCool|AirLoopHVAC:UnitaryHeatCool:VAVChangeoverBypass AirLoopHVAC:UnitaryHeatOnly|AirLoopHVAC:UnitaryHeatPump:AirToAir AirLoopHVAC:UnitaryHeatPump:AirToAir:MultiSpeed|AirLoopHVAC:UnitaryHeatPump:WaterToAir AirLoopHVAC:UnitarySystem|AirTerminal:DualDuct:ConstantVolume AirTerminal:DualDuct:VAV|AirTerminal:DualDuct:VAV:OutdoorAir AirTerminal:SingleDuct:ConstantVolume:CooledBeam|AirTerminal:SingleDuct:ConstantVolume:FourPipeInduction AirTerminal:SingleDuct:ConstantVolume:Reheat|AirTerminal:SingleDuct:ParallelPIU:Reheat AirTerminal:SingleDuct:SeriesPIU:Reheat|AirTerminal:SingleDuct:Uncontrolled AirTerminal:SingleDuct:VAV:HeatAndCool:NoReheat|AirTerminal:SingleDuct:VAV:HeatAndCool:Reheat AirTerminal:SingleDuct:VAV:NoReheat|AirTerminal:SingleDuct:VAV:Reheat AirTerminal:SingleDuct:VAV:Reheat:VariableSpeedFan|Boiler:HotWater Boiler:Steam|Branch Chiller:Absorption|Chiller:Absorption:Indirect Chiller:CombustionTurbine|Chiller:ConstantCOP Chiller:Electric|Chiller:Electric:EIR Chiller:Electric:ReformulatedEIR|Chiller:EngineDriven ChillerHeater:Absorption:DirectFired|ChillerHeater:Absorption:DoubleEffect ChillerHeaterPerformance:Electric:EIR|Coil:Cooling:DX:MultiSpeed Coil:Cooling:DX:SingleSpeed|Coil:Cooling:DX:SingleSpeed:ThermalStorage Coil:Cooling:DX:TwoSpeed|Coil:Cooling:DX:VariableRefrigerantFlow Coil:Cooling:DX:VariableSpeed|Coil:Cooling:Water Coil:Cooling:Water:DetailedGeometry|Coil:Cooling:WaterToAirHeatPump:EquationFit Coil:Cooling:WaterToAirHeatPump:VariableSpeedEquationFit|Coil:Heating:DX:MultiSpeed Coil:Heating:DX:SingleSpeed|Coil:Heating:DX:VariableRefrigerantFlow Coil:Heating:DX:VariableSpeed|Coil:Heating:Electric Coil:Heating:Electric:MultiStage|Coil:Heating:Gas Coil:Heating:Gas:MultiStage|Coil:Heating:Steam Coil:Heating:Water|Coil:Heating:WaterToAirHeatPump:EquationFit Coil:Heating:WaterToAirHeatPump:VariableSpeedEquationFit|CoilPerformance:DX:Cooling CondenserLoop|Controller:OutdoorAir Controller:WaterCoil|CoolingTower:SingleSpeed CoolingTower:TwoSpeed|CoolingTower:VariableSpeed CoolingTower:VariableSpeed:Merkel|EvaporativeCooler:Indirect:ResearchSpecial EvaporativeFluidCooler:SingleSpeed|EvaporativeFluidCooler:TwoSpeed Fan:ComponentModel|Fan:ConstantVolume Fan:OnOff|FanPerformance:NightVentilation Fan:VariableVolume|FluidCooler:SingleSpeed FluidCooler:TwoSpeed|HeaderedPumps:ConstantSpeed HeaderedPumps:VariableSpeed|HeatExchanger:AirToAir:SensibleAndLatent HeatExchanger:FluidToFluid|Humidifier:Steam:Electric HVACTemplate:Plant:Boiler|HVACTemplate:Plant:Chiller HVACTemplate:Plant:Tower|HVACTemplate:System:ConstantVolume HVACTemplate:System:DedicatedOutdoorAir|HVACTemplate:System:DualDuct HVACTemplate:System:PackagedVAV|HVACTemplate:System:Unitary HVACTemplate:System:UnitaryHeatPump:AirToAir|HVACTemplate:System:UnitarySystem HVACTemplate:System:VAV|HVACTemplate:System:VRF HVACTemplate:Zone:BaseboardHeat|HVACTemplate:Zone:ConstantVolume HVACTemplate:Zone:DualDuct|HVACTemplate:Zone:FanCoil HVACTemplate:Zone:IdealLoadsAirSystem|HVACTemplate:Zone:PTAC HVACTemplate:Zone:PTHP|HVACTemplate:Zone:Unitary HVACTemplate:Zone:VAV|HVACTemplate:Zone:VAV:FanPowered HVACTemplate:Zone:VAV:HeatAndCool|HVACTemplate:Zone:VRF HVACTemplate:Zone:WaterToAirHeatPump|PlantComponent:TemperatureSource PlantEquipmentOperation:ComponentSetpoint|PlantLoop Pump:ConstantSpeed|Pump:VariableSpeed Pump:VariableSpeed:Condensate|Sizing:System SolarCollector:FlatPlate:PhotovoltaicThermal|ThermalStorage:ChilledWater:Mixed ThermalStorage:ChilledWater:Stratified|UnitarySystemPerformance:HeatPump:Multispeed WaterHeater:Mixed|WaterHeater:Stratified ZoneHVAC:Baseboard:Convective:Electric|ZoneHVAC:Baseboard:Convective:Water ZoneHVAC:Baseboard:RadiantConvective:Electric|ZoneHVAC:Baseboard:RadiantConvective:Steam ZoneHVAC:Baseboard:RadiantConvective:Water|ZoneHVAC:EnergyRecoveryVentilator ZoneHVAC:EvaporativeCoolerUnit|ZoneHVAC:FourPipeFanCoil ZoneHVAC:HighTemperatureRadiant|ZoneHVAC:IdealLoadsAirSystem ZoneHVAC:LowTemperatureRadiant:Electric|ZoneHVAC:LowTemperatureRadiant:VariableFlow ZoneHVAC:OutdoorAirUnit|ZoneHVAC:PackagedTerminalAirConditioner ZoneHVAC:PackagedTerminalHeatPump|ZoneHVAC:TerminalUnit:VariableRefrigerantFlow ZoneHVAC:UnitHeater|ZoneHVAC:UnitVentilator ZoneHVAC:VentilatedSlab|ZoneHVAC:WaterToAirHeatPump [ZoneHVAC:WindowAirConditioner](../input-output-reference/page-032.html#zonehvacwindowairconditioner)|
User or External Zone Design Flow Rate Inputs[LINK]
In EnergyPlus the autosizing calculations start with a calculation of the zone design air flow rates using zone by zone design day simulations. The resulting zone design air flow rates and daily air flow sequences are used in the subsequent HVAC and central plant air and fluid flow design calculations and in the component autosizing calculations. The user can override or change the calculated zone design air flow rates in several ways.
User or External System Design Flow Rate Inputs[LINK]
Using the results of the zone design air flow rate calculation (including any user input or altered flow rates) EnergyPlus proceeds to calculate central air system flow rates and cooling and heating loads. The results of this calculation can be overridden in the following way.
For each system (AirLoopHVAC](page-028.html#airloophvac)), in the corresponding [Sizing:System object, specify Cooling Design Air Flow Method to be Flow/System and input a value for Cooling Design Air Flow Rate. **Similarly for heating specify Heating Design Air Flow Method to be Flow/System and input a value for Heating Design Air Flow Rate.
DesignSpecification:OutdoorAir[LINK]
This object allows for the outdoor air requirements to be defined in a common location for use by other objects. This object may be referenced by name from other objects (e.g., VAV terminal units) as required to identify an outdoor air quantity for use by that object. Note that a zone name Is not included as an input to this zone outdoor air definition and the number of people in a zone, zone floor area, and zone volume can only be determined after this object has been referenced by another. A single zone outdoor air definition may be referenced by multiple objects to specify that the same outdoor air requirements are used by those objects or multiple zone outdoor air objects may be defined and referenced by other objects as needed. If multiple zone outdoor air definitions are used, each outdoor air definition must have a unique name.
Field: Name[LINK]
Unique identifying name. Any reference to this name by other objects will denote that the following outdoor air requirements will be used.
Field: Outdoor Air Method[LINK]
The input must be either Flow/Person, Flow/Area, Flow/[Zone](../input-output-reference/page-011.html#zone), AirChanges/Hour, Sum, or Maximum. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the actual zone occupancy to calculate a zone outdoor air flow rate. Flow/Area means that the program will use the input from the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area and the actual zone floor area as the zone outdoor air flow rate. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone) as the zone outdoor air flow rate. AirChanges/Hour means that the program will use the input from the field Air Changes per Hour and the actual zone volume (divided by 3600 seconds per hour) as the zone outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area, Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone), and Air Changes per Hour (using the associated conversions to m3/s for each field) will be added to obtain the zone outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area, Outdoor Air Flow per [Zone](../input-output-reference/page-011.html#zone), and Air Changes per Hour (using the associated conversions to m3/s for each field) will be used as the zone outdoor air flow rate. The default is Flow/Person.
Field: Outdoor Air Flow per Person[LINK]
The design outdoor air volume flow rate per person for this zone in cubic meters per second per person. 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 during sizing calculations and are applied during the remainder of the simulation. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
Field: Outdoor Air Flow per Zone Floor Area[LINK]
The design outdoor air volume flow rate per square meter of floor area (units are m3/s-m2). This input is used if Outdoor Air Method is Flow/Area, Sum or Maximum. The default value for this field is 0.
Field: Outdoor Air Flow 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. The default value for this field is 0.
Field: Outdoor Air Flow Changes per Hour[LINK]
The design outdoor air volume flow rate in air changes per hour. This factor is used along with the [Zone](../input-output-reference/page-011.html#zone) Volume and converted to cubic meters per second. This input field is used if Outdoor Air Method is AirChanges/Hour, Sum or Maximum. The default value for this field is 0.
Field: Outdoor Air Flow Rate Fraction Schedule Name[LINK]
This field is the name of schedule that defines how outdoor air requirements change over time. The field is optional. If used, then the schedule values are multiplied by the outdoor air flow rate defined by the previous fields. The schedule values must be between 0 and 1, inclusive.
An IDF example:
DesignSpecification:ZoneAirDistribution[LINK]
This object is used to describe the air distribution effectiveness and fraction of secondary recirculation air (return air not directly mixed with outdoor air) of a zone. It is referenced by the Sizing:Zone and [Controller:MechanicalVentilation](../input-output-reference/page-051.html#controllermechanicalventilation) objects.
Field: Name[LINK]
The unique user assigned name for an instance of this object. Any other object referencing this object will use this name.
Field: Zone Air Distribution Effectiveness in Cooling Mode[LINK]
The positive numeric input for this field is the zone air distribution effectiveness when the zone is in cooling mode. Default value of this field is 1.0. ASHRAE Standard 62.1-2010 provides typical values.
Field: Zone Air Distribution Effectiveness in Heating Mode[LINK]
The positive numeric input for this field is the zone air distribution effectiveness when the zone is in heating mode. Default value of this field is 1.0. ASHRAE Standard 62.1-2010 provides typical values as follows:
Field: Zone Air Distribution Effectiveness Schedule Name[LINK]
This optional field input points to a schedule with values of zone air distribution effectiveness. It provides a more flexible way of specifying zone air distribution effectiveness if it changes with time and/or system operating status and controls. If the schedule is specified, the zone air distribution effectiveness in cooling mode and heating mode will be ignored.
Field: Zone Secondary Recirculation Fraction[LINK]
The non-negative numeric input for this field is the fraction of a zone’s recirculation air that does not directly mix with the outdoor air. The zone secondary recirculation fraction Er is determined by the designer based on system configuration. For plenum return systems with secondary recirculation (e.g., fan-powered VAV with plenum return) Er is usually less than 1.0, although values may range from 0.1 to 1.2 depending upon the location of the ventilation zone relative to other zones and the air handler. For ducted return systems with secondary recirculation (e.g., fan-powered VAV with ducted return), Er is typically 0.0, while for those with system-level recirculation (e.g, dual-fan dual-duct systems with ducted return) Er is typically 1.0. For other system types, Er is typically 0.75. Minimum is 0.0, and default is 0.0 for single-path systems (also to maintain backward compatibility). For parallel fan-powered VAV systems, the secondary ventilation path only functions (Er > 0.0) when the fans in the VAV boxes operate, which is during heating. The local ventilation path and the benefits of secondary recirculation disappear during cooling, when the local parallel fans are off (Er = 0.0).
An example of this in an IDF context is shown:
Sizing:Parameters[LINK]
This object allows the user to specify global heating and cooling sizing ratios. These ratios will be applied at the zone level to all of the zone heating and cooling loads and air flow rates. These new loads and air flow rates are then used to calculate the system level flow rates and capacities and are used in all component sizing calculations.
The user can also specify the width (in load timesteps) of a moving average window which can be used to smooth the calculated zone design flow sequences. The use of this parameter is described below.
Field: Heating Sizing Factor[LINK]
The global heating sizing ratio applied to all of the zone design heating loads and air flow rates.
Field: Cooling Sizing Factor[LINK]
The global cooling sizing ratio applied to all of the zone design cooling loads and air flow rates
Field: Timesteps in Averaging Window[LINK]
The number of load timesteps in the zone design flow sequence averaging window. The default is 1, in which case the calculated zone design flow rates are averaged over the load timestep.
The zone design air flow rate calculation is performed assuming a potentially infinite supply of heating or cooling air at a fixed temperature. Thus the calculated design air flow rate will always be able to meet any load or change in load no matter how large or abrupt. In reality air flow rates are limited by duct sizes and fan capacities. The idealized zone design flow calculation may result in unrealistically large flow rates, especially if the user is performing the sizing calculations using thermostat schedules with night setup or setback. The calculated zone design flow rates are always averaged over the load timestep. The user may want to perform a broader average to mitigate the effect of thermostat setup and setback and prevent the warm up or cool down flow rates from dominating the design flow rate calculation.. Specifying the width of the averaging window allows the user to do this.
For example, if the load calculation timestep is 15 minutes and the user specifies the Timesteps in Averaging [Window](../input-output-reference/page-011.html#window) to be 4, the zone design air flows will be averaged over a time period of 1 hour. Specifying 8 would result in averaging over a 2 hour period.
Sizing Parameters Outputs[LINK]
The sizing factors and the averaging window size are reported out on the eplusout.eio file. An example is:
OutputControl:Sizing:Style[LINK]
As described early in the document (see: EnergyPlus Output Processing), the user may select the “style” for the sizing result files (epluszsz., eplusssz.). This object applies to all sizing output files.
Field: Column Separator[LINK]
For this field, the desired separator for columns is entered. “Comma” creates comma separated fields/columns in the outputs (eplus.csv files are created). “Tab” creates tab separated fields/columns in the outputs (eplus.tab files are created). “Fixed” creates space separated fields/columns in the outputs (eplus.txt files are created) but these are not necessarily lined up for easy printing.
Note that both tab and comma separated files easily import into Excel™ or other spreadsheet programs. The tab delimited files can also be viewed by text editors, word processing programs and easily converted to “tables” within those programs.
Sizing:Zone[LINK]
The Sizing:Zone object provides the data needed to perform a zone design air flow calculation for a single zone. This calculation assumes a variable amount of supply air at a fixed temperature and humidity. The information needed consists of the zone inlet supply air conditions: temperature and humidity ratio for heating and cooling. The calculation is done for every design day included in the input. The maximum cooling load and air flow and the maximum heating load and air flow are then saved for the system level design calculations and for the component automatic sizing calculations.
The Sizing:Zone object is also the place where the user can specify the design outdoor air flow rate by referencing the name of a design specification outdoor air object. This can be specified in a number of ways (ref. DesignSpecification:OutdoorAir).This data is saved for use in the system sizing calculation or for sizing zone components that use outdoor air.
The user can also place limits on the heating and design cooling air flow rates. See Heating Design Air Flow Method and Cooling Design Air Flow Method below and the explanations of the various heating and cooling flow input fields.
Field: Zone Name[LINK]
The name of the [Zone](../input-output-reference/page-011.html#zone) corresponding to this Sizing:[Zone](../input-output-reference/page-011.html#zone) object. This is the zone for which the design air flow calculation will be made using the input data of this Sizing:[Zone](../input-output-reference/page-011.html#zone) Object.
Field: Zone Cooling Design Supply Air Temperature Input Method[LINK]
The input must be either SupplyAirTemperature or TemperatureDifference. SupplyAirTemperature means that the user inputs from the fields of [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature will be used to determine the zone cooling design air flow rates. TemperatureDifference means that the user inputs from the fields of [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Difference will be used to determine the zone cooling design air flow rates.
Field: Zone Cooling Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone cooling design air flow rate calculation. Air is supplied to the zone at this temperature during the cooling design day simulation, The zone load is met by varying the zone air flow rate. The maximum zone flow rate is saved as the zone cooling design air flow rate. This field is only used when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method = SupplyAirTemperature.
Field: Zone Cooling Design Supply Air Temperature Difference[LINK]
The temperature difference between cooling design supply air temperature and room air temperature in degrees Celsius for the zone cooling design air flow rate calculation. Air is supplied to the zone at this temperature during the cooling design day simulation. The zone load is met by varying the zone air flow rate. The maximum zone flow rate is saved as the zone cooling design air flow rate. This field is only used when [Zone](../input-output-reference/page-011.html#zone) Cooling Design Supply Air Temperature Input Method = TemperatureDifference.
Field: Zone Heating Design Supply Air Temperature Input Method[LINK]
The input must be either SupplyAirTemperature or TemperatureDifference. SupplyAirTemperature means that the user inputs from the fields of [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature will be used to determine the zone heating design air flow rates. TemperatureDifference means that the user inputs from the fields of [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Difference will be used to determine the zone heating design air flow rates.
Field: Zone Heating Design Supply Air Temperature[LINK]
The supply air temperature in degrees Celsius for the zone heating design air flow rate calculation. Air is supplied to the zone at this temperature during the heating design day simulation, The zone load is met by varying the zone air flow rate. The maximum zone flow rate is saved as the zone heating design air flow rate. This field is only used when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method = SupplyAirTemperature.
Field: Zone Heating Design Supply Air Temperature Difference[LINK]
The temperature difference between heating design supply air temperature and room air temperature in degrees Celsius for the zone heating design air flow rate calculation. Air is supplied to the zone at this temperature during the heating design day simulation. The zone load is met by varying the zone air flow rate. The maximum zone flow rate is saved as the zone heating design air flow rate. This field is only used when [Zone](../input-output-reference/page-011.html#zone) Heating Design Supply Air Temperature Input Method = TemperatureDifference.
Field: Zone Cooling Design Supply Air Humidity Ratio[LINK]
The humidity ratio in kilograms of water per kilogram of dry air of the supply air in the zone cooling design air flow rate calculation.
Field: Zone Heating Design Supply Air Humidity Ratio[LINK]
The humidity ratio in kilograms of water per kilogram of dry air of the supply air in the zone heating design air flow rate calculation.
Field: Design Specification Outdoor Air Object Name[LINK]
This alpha field specifies the name of a DesignSpecification:OutdoorAir object which specifies the design outdoor air flow rate for the zone.
Field: Zone Heating Sizing Factor[LINK]
This input is a zone level heating sizing ratio. The zone design heating air flow rates and loads will be multiplied by the number input in this field. This input overrides the building level sizing factor input in the Sizing:Parameters object. And, of course, if this field is blank or zero, the global heating sizing factor from the Sizing:Parameters object is used.
Field: Zone Cooling Sizing Factor[LINK]
This input is a zone level cooling sizing ratio. The zone design cooling air flow rates and loads will be multiplied by the number input in this field. This input overrides the building level sizing factor input in the Sizing:Parameters object. And, of course, if this field is blank or zero, the global cooling sizing factor from the Sizing:Parameters object is used.
Field: Cooling Design Air Flow Method[LINK]
The input must be either Flow/Zone](page-011.html#zone), DesignDay, or DesignDayWithLimit. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Cooling Design Air Flow Rate as the zone design cooling air flow rate. DesignDay means the program will calculate the zone design cooling air flow rate using the [Sizing:[Zone](#zone) input data and a design day simulation without imposing any limits other than those set by the minimum outside air requirements. DesignDayWithLimit means that the maximum from Cooling Minimum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area and Cooling Minimum Air Flow will set a lower limit on the **design maximum cooling air flow rate. The default method is DesignDay: i.e., the program uses the calculated design values subject to ventilation requirements.
Field: Cooling Design Air Flow Rate[LINK]
The design zone cooling air flow rate in cubic meters per second. This input is used if Cooling Design Air Flow Method is specified as Flow/Zone. This value will be multiplied by the global or zone sizing factor and by zone multipliers.
Field: Cooling Minimum Air Flow per Zone Floor Area[LINK]
The minimum zone cooling volumetric flow rate per square meter (units are m3/s-m2). This field is used when Cooling Design Air Flow Method is specified as DesignDayWithLimit. In this case it sets a lower bound on the zone design cooling air flow rate. In all cases the maximum flow derived from Cooling Minimum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area, Cooling Minimum Air Flow, and Cooling Minimum Air Flow Fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is .000762, corresponding to .15 cfm/ft2. The applicable sizing factor is not applied to this value.
Field: Cooling Minimum Air Flow[LINK]
The minimum zone cooling volumetric flow rate in m3/s. This field is used when Cooling Design Air Flow Method is specified as DesignDayWithLimit. In this case it sets a lower bound on the zone design cooling air flow rate. In all cases the maximum flow derived from Cooling Minimum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area, Cooling Minimum Air Flow, and Cooling Minimum Air Flow Fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is zero. The applicable sizing factor is not applied to this value.
Field: Cooling Minimum Air Flow Fraction[LINK]
The minimum zone design cooling volumetric flow rate expressed as a fraction of the zone design cooling volumetric flow rate. . In all cases the maximum flow derived from Cooling Minimum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area, Cooling Minimum Air Flow, and Cooling Minimum Air Flow Fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is zero. This input is currently used in sizing the fan minimum flow rate. It does not currently affect other component autosizing.
Field: Heating Design Air Flow Method[LINK]
The input must be either Flow/Zone](page-011.html#zone), DesignDay, or DesignDayWithLimit. Flow/[Zone](../input-output-reference/page-011.html#zone) means that the program will use the input of the field Heating Design Air Flow Rate as the zone design heating air flow rate. DesignDay means the program will calculate the zone design heating air flow rate using the [Sizing:[Zone](#zone) input data and a design day simulation without imposing any limits other than those set by the minimum outside air requirements. DesignDayWithLimit means that the maximum from Heating Maximum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area and Heating Maximum Air Flow will set a lower limit on the **design maximum heating air flow rate. The default method is DesignDay: i.e., the program uses the calculated design values subject to ventilation requirements.
Field: Heating Design Air Flow Rate[LINK]
The design zone heating air flow rate in cubic meters per second. This input is used if Heating Design Air Flow Method is specified as Flow/Zone. This value will be multiplied by the global or zone sizing factor and by zone multipliers.
Field: Heating Maximum Air Flow per Zone Floor Area[LINK]
The maximum zone heating volumetric flow rate per square meter (units are m3/s-m2). This field is used when Heating Design Air Flow Method is specified as DesignDayWithLimit. In this case it sets an upper bound on the zone design heating air flow rate. For this and the next two input fields, the maximum flow derived from Heating Maximum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area, Heating Maximum Air Flow, and Heating Maximum Air Flow Fraction is used to set a maximum heating supply air flow rate for the zone for VAV systems. The default is .002032, corresponding to .40 cfm/ft2. If the maximum heating design flow rate calculated using these input fields is greater than the design heating flow rate calculated during sizing, these input fields have no impact on sizing. It may be more appropriate to select only one of these three fields to calculate the maximum heating design flow rate (i.e., if one ore more of these three fields is 0, it will not be used in calculating the maximum heating design flow rate).
Field: Heating Maximum Air Flow[LINK]
The maximum zone heating volumetric flow rate in m3/s. This field is used when Heating Design Air Flow Method is specified as DesignDayWithLimit. In this case it sets an upper bound on the zone design heating air flow rate. For this field and the two input fields just prior to and after this field,,the maximum flow derived from Heating Maximum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area, Heating Maximum Air Flow, and Heating Maximum Air Flow Fraction is used to set a maximum heating supply air flow rate for the zone for VAV systems. The default is .1415762, corresponding to 300 cfm. If the maximum heating design flow rate calculated using these input fields is greater than the design heating flow rate calculated during sizing, these input fields have no impact on sizing. It may be more appropriate to select only one of these three fields to calculate the maximum heating design flow rate (i.e., if one ore more of these three fields is 0, it will not be used in calculating the maximum heating design flow rate).
Field: Heating Maximum Air Flow Fraction[LINK]
The maximum zone design heating volumetric flow rate expressed as a fraction of the zone design cooling volumetric flow rate. For this and the previous two input fields, the maximum flow derived from Heating Maximum Air Flow per [Zone](../input-output-reference/page-011.html#zone) Floor Area, Heating Maximum Air Flow, and Heating Maximum Air Flow Fraction is used to set a maximum heating supply air flow rate for the zone for VAV systems. The default is 0.3. If the maximum heating design flow rate calculated using these input fields is greater than the design heating flow rate calculated during sizing, these input fields have no impact on sizing. It may be more appropriate to select only one of these three fields to calculate the maximum heating design flow rate (i.e., if one ore more of these three fields is 0, it will not be used in calculating the maximum heating design flow rate).
Field: Design Specification Zone Air Distribution Object Name[LINK]
The name of the DesignSpecification:ZoneAirDistribution object, defining the air distribution effectiveness and secondary recirculation air fraction, that applies to the zone or zone list. This object may be used for the same zone in the Controller:MechanicalVentilation](page-051.html#controllermechanicalventilation) object if no such [DesignSpecification:ZoneAirDistribution object is specified.
An IDF example:
Zone Sizing Outputs[LINK]
The zone design air flow rates and loads are output onto the local file “epluszsz.” where is the extension from the sizing style object (default is csv – a comma separated file epluszsz.csv). The columns are clearly labeled. It will easily import into Excel or other spreadsheet program that accepts delimited files. All of these values are design air flow rates and loads calculated by the program. No sizing factors have been applied.
The calculated zone design air flow rates and the user input or altered zone design air flow rates are also reported on the eplusout.eio file. The values are printed out for each zone as comma separated records beginning with Zone Sizing. Items output on the eio file are: zone name, load type (heating or cooling), design load, calculated design air flow rate, user design air flow rate, design day name, time of peak, outside temperature at peak, outside humidity ratio at peak.
Sizing:System[LINK]
The Sizing:System object contains the input needed to perform a central forced air system design air flow, heating capacity, and cooling capacity calculation for a system serving one or more zones. The information needed consists of the outside environmental conditions and the design supply air temperatures, outdoor air flow rate, and minimum system air flow ratio.
The outside conditions come from the design days in the input. A system sizing calculation is performed for every design day in the input file and the resulting maximum heating and cooling air flow rates and capacities are saved for use in the component sizing calculations.
Supply air conditions are specified by inputting a supply air temperature for cooling, a supply air temperature for heating, and a preheat temperature.
The system sizing calculation sums the zone design air flow rates to obtain a system supply air flow rate. The design conditions and the outdoor air flow rate are used to calculate a design mixed air temperature. The temperature plus the design supply air temperatures allows the calculation of system design heating and cooling capacities.
Field: AirLoop Name[LINK]
The name of the AirLoopHVAC](page-028.html#airloophvac) corresponding to this [Sizing:System object. This is the air system for which the design calculation will be made using the input data of this Sizing:System Object.
Field: Type of Load to Size On[LINK]
The user specified type of load on which to size the central system. The choices are Sensible, Latent, Total and VentilationRequirement. Only Sensible and VentilationRequirement are operational. Sensible means that the central system supply air flow rate will be determined by combining the zone design air flow rates, which have been calculated to meet the zone sensible loads from the design days. VentilationRequirement means that the central system supply air flow rate will be determined by the system ventilation requirement.
Field: Design Outdoor Air Flow Rate[LINK]
The design outdoor air flow rate in cubic meters per second. Generally this should be the minimum outdoor air flow. It is used for both heating and cooling design calculations. The assumption for cooling is that any outdoor air economizer will be closed. If Autosize is input the outdoor air flow rate will be taken from the sum of the zone outdoor air flow rates or calculated based on the System Outdoor Air Method selection (field below).
Field: Minimum System Air Flow Ratio[LINK]
The design minimum central air flow ratio. This ratio is the minimum system air flow rate divided by the maximum system air flow rate. The value must be between 0 and 1. For constant volume systems the ratio should be set to 1. Note that this ratio should be set to reflect what the user expects the system flow rate to be when maximum heating demand occurs. This ratio is used in calculating the central system heating capacity. Thus if the system is VAV with the zone VAV dampers held at minimum flow when there is a zone heating demand, this ratio should be set to the minimum flow ratio. If the zone VAV dampers are reverse action and can open to full flow to meet heating demand, this ratio should be set to 1.
Field: Preheat Design Temperature[LINK]
The design air temperature exiting the preheat coil (if any) in degrees Celsius.
Field: Preheat Design Humidity Ratio[LINK]
The design humidity ratio exiting the preheat coil (if any) in kilograms of water per kilogram of dry air. (kgWater/kgDryAir)
Field: Precool Design Temperature[LINK]
The design air temperature exiting the precooling coil (if any) in degrees Celsius.
Field: Precool Design Humidity Ratio[LINK]
The design humidity ratio exiting the precooling coil (if any) in kilograms of water per kilogram of dry air. (kgWater/kgDryAir)
Field: Central Cooling Design Supply Air Temperature[LINK]
The design supply air temperature for cooling in degrees Celsius. This should be the temperature of the air exiting the central cooling coil.
Field: Central Heating Design Supply Air Temperature[LINK]
The design supply air temperature for heating in degrees Celsius. This can be either the reset temperature for a single duct system or the actual hot duct supply air temperature for dual duct systems. It should be the temperature at the exit of the main heating coil.
Field: Sizing Option[LINK]
If the input is coincident the central system air flow rate will be sized on the sum of the coincident zone air flow rates. If the input is noncoincident the central system air flow rate will be sized on the sum of the noncoincident zone air flow rates. The default is noncoincident.
Field: 100% Outdoor Air in Cooling[LINK]
Entering Yes means the system will be sized for cooling using 100% outdoor air. Entering No means the system will be sized for cooling using minimum outside air (the default).
Field: 100% Outdoor Air in Heating[LINK]
Entering Yes means the system will be sized for heating using 100% outdoor air. Entering No means the system will be sized for heating using minimum outside air (the default).
Field: Central Cooling Design Supply Air Humidity Ratio[LINK]
The design humidity ratio in kilograms of water per kilogram of dry air at the exit of the central cooling coil. (kgWater/kgDryAir) The default is .008.
Field: Central Heating Design Supply Air Humidity Ratio[LINK]
The design humidity ratio in kilograms of water per kilogram of dry air at the exit of the central heating coil. (kgWater/kgDryAir) The default is .008.
Field: Cooling Design Air Flow Method[LINK]
The input must be either DesignDay or Flow/System. DesignDay means the program will calculate the system design cooling air flow rate using the System Sizing input data and a design day simulation. Flow/System means that the program will use the input of the field Cooling Design Air Flow Rate as the system design cooling air flow rate. The default method is DesignDay: i.e., the program uses the calculated design values.
Field: Cooling Design Air Flow Rate[LINK]
The design system cooling air flow rate in cubic meters per second. This input is an alternative to using the program calculated value. This input is used if Cooling Design Air Flow Method is Flow/System. This value will not be multiplied by any sizing factor or by zone multipliers. If using zone multipliers, this value must be large enough to serve the multiplied zones.
Field: Heating Design Air Flow Method[LINK]
The input must be either DesignDay or Flow/System. DesignDay means the program will calculate the system design heating air flow rate using the System Sizing input data and a design day simulation. Flow/System means that the program will use the input of the field Heating Design Air Flow Rate as the system design heating air flow rate. . The default method is DesignDay: i.e., the program uses the calculated design values.
Field: Heating Design Air Flow Rate[LINK]
The design system heating air flow rate in cubic meters per second. This input is an alternative to using the program calculated value. This input is used if Heating Design Air Flow Method is Flow/System. This value will not be multiplied by any sizing factor or by zone multipliers. If using zone multipliers, this value must be large enough to serve the multiplied zones.
Field: System Outdoor Air Method[LINK]
The method used to calculate the system minimum outdoor air flow. The two choices are ZoneSum and VentilationRateProcedure (VRP). ZoneSum sums the outdoor air flows across all zones served by the system. VRP uses the multi-zone equations defined in 62.1-2007 to calculate the system outdoor air flow. VRP considers zone air distribution effectiveness and zone diversification of outdoor air fractions.
Field: Zone Maximum Outdoor Air Fraction[LINK]
This positive numeric input is the zone maximum outdoor air fraction. For an air loop, when a zone requires outdoor air higher than the user specified [Zone](../input-output-reference/page-011.html#zone) Maximum Outdoor Air Fraction, the zone supply air flow will be increased to cap the outdoor air fraction at the maximum value. This allows the system level outdoor air flow to be reduced while the total supply air flow increases. Valid values are from 0 to 1.0. Default is 1.0 which indicates zones can have 100% outdoor air maintaining backward compatibility. This inputs work for constant volume air systems, single and dual duct VAV systems.
An IDF example:
System Sizing Outputs[LINK]
The system design air flow rates and heating and cooling capacities are output onto the local file “eplusssz.” where is the extension from the sizing style object (default is csv – a comma separated file eplusssz.csv). The columns are clearly labeled. It will easily import into Excel or other spreadsheet program that accepts delimited files. The results are calculated values and do not include any user input system flow rates.
The calculated system design air flow rates and the user input system design air flow rates are also reported on the eplusout.eio file. The values are printed out for each system as comma separated records beginning with System Sizing. An example is:
Sizing:Plant[LINK]
The Sizing:Plant object contains the input needed for the program to calculate plant loop flow rates and equipment capacities when autosizing. This information is initially used by components that use water for heating or cooling such as hot or chilled water coils to calculate their maximum water flow rates. These flow rates are then summed for use in calculating the Plant Loop flow rates.
The program will size any number of chilled water, hot water, condenser water and other plant loops. There should be one Sizing:Plant object for each plant loop that is to be autosized.
Field: Plant or Condenser Loop Name[LINK]
The name of a Plant Loop or Condenser Loop object corresponding to this Sizing:Plant object. This is the plant loop for which this data will be used for calculating the loop flow rate.
Field: Loop Type[LINK]
The possible inputs are Heating, Steam, Cooling, or Condenser.
Field: Design Loop Exit Temperature[LINK]
The water temperature in degrees Celsius at the exit of the supply side of the plant loop, Thus this is the temperature of the water supplied to the inlet of chilled or hot water coils and other equipment that places loads on a plant loop.
Field: Loop Design Temperature Difference[LINK]
The design temperature rise (for cooling or condenser loops) or fall (for heating loops) in degrees Celsius across the demand side of a plant loop. This temperature difference is used by component models to determine flow rates required to meet design capacities. Larger values lead to smaller design flow rates.
An IDF example:
Plant Sizing Outputs[LINK]
The loop flow rates are reported on the eplusout.eio file along with the component sizing results.
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