Exercise 2A. Add Unitary System with DX Cooling and Gas Heating (Furnace) Serving a Single Zone[LINK]
Objective: Learn how to describe a thermostat and unitary equipment using HVACTemplate objects.
- Open Exercise2.idf and save it as Exercise2A.idf. (Exercise2.idf contains the building envelope, internal loads, and some extra schedules to support the HVAC system descriptions which will be added in this Exercise.)
- Add a HVACTemplate:Thermostat object to define the thermostat setpoints for this simulation.
- Choose a name for the thermostat. This name will be referenced in the next step.
- For heating setpoints, use pre-defined schedule named “Office Heating Setpoints”.
- For cooling setpoints, use pre-defined schedule named “Office Cooling Setpoints”.
- Add a HVACTemplate:Zone:Unitary object serving the “NORTH PERIMETER” zone. Choose a name for the air handling system which will be added in Step 4. Use the thermostat name from step 2 for the thermostat field. Retain the defaults for the remaining fields.
- Add a HVACTemplate:System:Unitary object. The name of this system object must be the same name used in the zone object for “Air Handling System Name” field (See Step 3). Retain the defaults for all fields except the following:
- Availability Schedule = Office HVAC (predefined)
- Control Zone Name or Thermostat Location = NORTH PERIMETER
- Supply Fan Operating Mode Schedule Name = Continuous
- Heating Coil Type = Gas
- Minimum Outdoor Air Schedule Name = Office Minimum OA (predefined)
- Add a Sizing:Parameters object and set the sizing factor to 1.2 (for 20% oversizing).
- Edit the SimulationControl object and set the Zone and System sizing flags to “Yes”.
- Run the simulation and review output files, especially:
- err, there will be some warnings about meters that do no exist and the ABUPS report not being a full year. These will go away as more features are added and an annual run is simulated.
- DXF , drawing of building surfaces. (Try selecting the Southwest Isometric named view, then see how each zone is a separate drawing layer. In Voloview open the View Layers dialog. Click on the light bulbs to toggle display of each zone. In TrueView click on the Layer Properties Manager toolbar button. To toggle display of a layer, single-click a layer light bulb, then click apply.)
- SVG, block diagram of the HVAC system components. (HINT: right-click in the drawing and read the Help to learn how to navigate in the SVG viewer.)
- Main Results File (csv) and Meter File (Meter.csv).
- eio, zone and system sizing results
- Add output variables to report operation of the system (furnace) fan, heating coil, and cooling coil. Reference the RDD output file for variable names.
- Re-run the simulation and review results again.
- Note during hour 7 of the summer design day that “NORTH PERIMETER:Zone/Sys Sensible Heating RateW” is nonzero, but the heating coil is off and the DX cooling coil shows a load. Why? This report variable reports the impact of the system on the zone (not the zone’s demand for heating or cooling), averaged over the hour. The system fan is scheduled on at 6 a.m., but the outside air dampers are closed. The zone is not warm enough from the night to require cooling, so the circulating fan heat warms the zone slightly for a portion of the hour until the zone temperature exceeds the cooling setpoint and the DX coil comes on for the remainder of the hour. If the economizer were active, this would not occur.
Exercise 2B. Add VAV System with Reheat Serving Four Zones with Chiller and Boiler Plant[LINK]
Objective: Learn how to describe a VAV system with central plant using HVACTemplate objects.
- Save Exercise2A.idf as Exercise2B.idf.
- Add a HVACTemplate:System:VAV object. Retain the defaults for all fields except the following:
- Air Handling System Name =
- System Availability Schedule = Office HVAC (predefined)
- Cooling Coil Design Setpoint= 13C (55.4F)
- Minimum Outdoor Air Schedule Name = Office Minimum OA (predefined)
- Economizer Type = FixedDryBulb
- Return Plenum Name = PLENUM
- Add four HVACTemplate:Zone:VAV objects serving the four remaining zones (South Perimeter, East Perimeter, West Perimeter, and Core). Retain the defaults for all fields except the following:
- Specify the same air handler name added in Step 2 (use the dropdown list)
- Specify the same thermostat control added in Exercise 2A Step 2 (again, use the dropdown list).
- Supply Air Minimum Flow Fraction = 0.2
- Reheat Coil Type = Hot Water
- Heating Damper Action = Reverse
- HINT: Define one HVACTemplate:Zone:VAV object, make the above changes to defaults, then press “Dup Obj” three times to duplicate the object, then edit the remaining three zone names.
- Add a HVACTemplate:Plant:ChilledWaterLoop object and assign a name. Retain the defaults for all fields except the following:
- Condenser Water Temperature Control Type = Specified Setpoint
- Add a HVACTemplate:Plant:Chiller object, type Electric Reciprocating Chiller with a nominal COP of 3.6, water cooled.
- Add a HVACTemplate:Plant:Tower object, type Two Speed.
- Add a HVACTemplate:Plant:HotWaterLoop object and assign a name. Retain the defaults for all fields.
- Add a natural gas fired hot water boiler using HVACTemplate:Plant:Boiler.
- Run the simulation, add desired report variables, and re-run the simulation. Review results and compare with results from Exercise 2A:
- Note how the heating and cooling rates for the NORTH PERIMETER zone are smaller than before. Why?
- Review the SVG drawing to see the components of the VAV system and water loops.
- Browse the expidf file in a text editor (or open in IDF Editor from File, Open, setting file type to expidf) to see the full detailed description of the HVAC systems using native EnergyPlus objects (the expanded result of the HVACTemplate preprocessor).
Exercise 2C. Annual Simulation[LINK]
Objective: Learn how to schedule report variables and create a monthly table report.
- Save Exercise2B.idf as Exercise2C.idf.
- Edit the SimulationControl object to turn off the design day simulations by setting “Run Simulation for Sizing Periods” to No and turn on the weather file (annual) simulation by setting “Run Simulation for Weather File Run Periods” to Yes..
- Edit existing Output:Variable and Output:Meter objects and change the reporting frequency from Hourly to Monthly.
- Locate the Output:Variable object for “Zone/Sys Air Temp” and duplicate it. Edit the new object and add a schedule “Office Occupancy 2”. This object will report zone temperatures averaged only during occupied periods (when “Office Occupancy 2” is greater than zero). The original instance of this report variable will average the zone temperatures over all hours.
- Add a new Output:Table:Monthly object:
- Name = Zone Temperature Report
- Open the rdd output file for Exercise2B in the text editor and find the following report variable names to copy and paste into the fields of the Report:Table:Monthly object in IDF Editor. Variable name and aggregation type are listed in pairs.
-
Zone Mean Air Temperature, SumOrAverage
-
Zone Mean Air Temperature, Maximum
-
Zone Mean Air Temperature, Minimum
-
Zone People Number of Occupants, HoursPositive
-
Zone Mean Air Temperature, SumOrAverageDuringHoursShown
-
Zone Mean Air Temperature, MaximumDuringHoursShown
-
Zone Mean Air Temperature, MinimumDuringHoursShown
- Edit Output:Table:SummaryReports to add the “Equipment Summary” report.
- Select Chicago TMY2 weather file and run the simulation.
- Review outputs. (Note the ABUPS report in the HTML file will now show a full year of results.) Especially review the Zone Temperatures table report in the HTML file. There will be a warning regarding Output:Table:Monthly, because there are no people in the PLENUM zone; this is normal.
Solution: Exercise 2[LINK]
This is a listing of new objects added in this Exercise.
Try not to look at this section until you have completed the Exercise.
Solution: Exercise 2A[LINK]
HVACTemplate:Thermostat,
Office Thermostat, !- Thermostat Name
Office Heating Setpoints,!- Thermostat Heating Setpoint Schedule
, !- Thermostat Constant Heating Setpoint {C}
Office Cooling Setpoints,!- Thermostat Cooling Setpoint Schedule
; !- Thermostat Constant Cooling Setpoint {C}
HVACTemplate:Zone:Unitary,
NORTH PERIMETER, !- Zone Name
North Zone Unitary, !- Air Handling System Name
Office Thermostat, !- Thermostat Name
autosize, !- Zone Supply Air Max Flow Rate {m3/s}
, !- Zone Supply Air Sizing Factor
Flow/Person, !- Zone Outside Air Method
0.00944, !- Zone Outside Air Flow Rate per Person {m3/s}
0.0, !- Zone Outside Air Flow per Zone Area {m3/s-m2}
0.0, !- Zone Outside Air Flow per Zone {m3/s}
, !- Zone Supply Plenum Name
, !- Zone Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule
autosize; !- Baseboard Heating Capacity {W}
HVACTemplate:System:Unitary,
North Zone Unitary, !- Air Handling System Name
Office HVAC, !- System Availability Schedule
NORTH PERIMETER, !- Control Zone Name or Thermostat Location
autosize, !- Supply Fan Max Flow Rate {m3/s}
Continuous, !- Supply Fan Operating Mode Schedule Name
0.7, !- Supply Fan Total Efficiency
600, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
Single-speed DX, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule
autosize, !- Cooling Coil Capacity {W}
autosize, !- Cooling Coil Rated SHR
3, !- Cooling Coil Rated COP
Gas, !- Heating Coil Type
, !- Heating Coil Availability Schedule
autosize, !- Heating Coil Capacity {W}
0.8, !- Gas Heating Coil Efficiency
, !- Gas Heating Coil Parasitic Electric Load {W}
autosize, !- Maximum Outside Air Flow Rate {m3/s}
autosize, !- Minimum Outside Air Flow Rate {m3/s}
Office Minimum OA, !- Minimum Outside Air Schedule Name
NoEconomizer, !- Economizer Type
NoLockout, !- Economizer Lockout
, !- Economizer Upper Temperature Limit {C}
, !- Economizer Lower Temperature Limit {C}
, !- Economizer Upper Enthalpy Limit {J/kg}
, !- Supply Plenum Name
, !- Return Plenum Name
BlowThrough, !- Supply Fan Placement
StayOff, !- Night Cycle Control
, !- Night Cycle Control Zone Name
None, !- Heat Recovery Type
0.7, !- Sensible Heat Recovery Effectiveness
0.65, !- Latent Heat Recovery Effectiveness
, !- Dehumidification Control Type
, !- Dehumidification Control Zone Name
, !- Dehumidification Setpoint {percent}
, !- Humidifier Type
, !- Humidifier Availability Schedule
, !- Humidifier Rated Capacity {m3/s}
, !- Humidifier Rated Electric Power {W}
, !- Humidifier Control Zone Name
; !- Humidifier Setpoint {percent}
Sizing:Parameters,
1.2; !- sizing factor
Output:Variable,*,Furnace Fan Part-Load Ratio,hourly;
Output:Variable,*,DX Cooling Coil Runtime Fraction,hourly;
Output:Variable,*,Heating Coil Runtime Fraction,hourly;
Solution: Exercise 2B[LINK]
HVACTemplate:System:VAV,
VAV with Reheat, !- Air Handling System Name
Office HVAC, !- System Availability Schedule
autosize, !- Supply Fan Max Flow Rate {m3/s}
autosize, !- Supply Fan Min Flow Rate {m3/s}
0.7, !- Supply Fan Total Efficiency
1000, !- Supply Fan Delta Pressure {Pa}
0.9, !- Supply Fan Motor Efficiency
1, !- Supply Fan Motor in Air Stream Fraction
ChilledWater, !- Cooling Coil Type
, !- Cooling Coil Availability Schedule
, !- Cooling Coil Setpoint Schedule
13, !- Cooling Coil Design Setpoint {C}
None, !- Heating Coil Type
, !- Heating Coil Availability Schedule
, !- Heating Coil Setpoint Schedule
10.0, !- Heating Coil Design Setpoint {C}
0.8, !- Gas Heating Coil Efficiency
, !- Gas Heating Coil Parasitic Electric Load {W}
None, !- Preheat Coil Type
, !- Preheat Coil Availability Schedule
, !- Preheat Coil Setpoint Schedule
7.2, !- Preheat Coil Design Setpoint {C}
0.8, !- Gas Preheat Coil Efficiency
, !- Gas Preheat Coil Parasitic Electric Load {W}
autosize, !- Maximum Outside Air Flow Rate {m3/s}
autosize, !- Minimum Outside Air Flow Rate {m3/s}
ProportionalMinimum, !- Minimum Outside Air Control Type
Office Minimum OA, !- Minimum Outside Air Schedule Name
FixedDryBulb, !- Economizer Type
NoLockout, !- Economizer Lockout
, !- Economizer Upper Temperature Limit {C}
, !- Economizer Lower Temperature Limit {C}
, !- Economizer Upper Enthalpy Limit {J/kg}
, !- Supply Plenum Name
PLENUM, !- Return Plenum Name
DrawThrough, !- Supply Fan Placement
InletVaneDampers, !- Supply Fan Part-Load Power Coefficients
StayOff, !- Night Cycle Control
, !- Night Cycle Control Zone Name
None, !- Heat Recovery Type
0.7, !- Sensible Heat Recovery Effectiveness
0.65, !- Latent Heat Recovery Effectiveness
None, !- Cooling Coil Setpoint Reset Type
None, !- Heating Coil Setpoint Reset Type
, !- Dehumidification Control Type
, !- Dehumidification Control Zone Name
, !- Dehumidification Setpoint {percent}
, !- Humidifier Type
, !- Humidifier Availability Schedule
, !- Humidifier Rated Capacity {m3/s}
, !- Humidifier Rated Electric Power {W}
, !- Humidifier Control Zone Name
; !- Humidifier Setpoint {percent}
HVACTemplate:Zone:VAV,
SOUTH PERIMETER, !- Zone Name
VAV with Reheat, !- Air Handling System Name
Office Thermostat, !- Thermostat Name
autosize, !- Zone Supply Air Max Flow Rate {m3/s}
, !- Zone Supply Air Sizing Factor
0.2, !- Zone Supply Air Min Flow Fraction
Flow/Person, !- Zone Outside Air Method
0.00944, !- Zone Outside Air Flow Rate per Person {m3/s}
0.0, !- Zone Outside Air Flow per Zone Area {m3/s-m2}
0.0, !- Zone Outside Air Flow per Zone {m3/s}
HotWater, !- Reheat Coil Type
, !- Reheat Coil Availability Schedule
Reverse, !- Zone Damper Heating Action
, !- Zone Supply Plenum Name
, !- Zone Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule
autosize; !- Baseboard Heating Capacity {W}
HVACTemplate:Zone:VAV,
EAST PERIMETER, !- Zone Name
VAV with Reheat, !- Air Handling System Name
Office Thermostat, !- Thermostat Name
autosize, !- Zone Supply Air Max Flow Rate {m3/s}
, !- Zone Supply Air Sizing Factor
0.2, !- Zone Supply Air Min Flow Fraction
Flow/Person, !- Zone Outside Air Method
0.00944, !- Zone Outside Air Flow Rate per Person {m3/s}
0.0, !- Zone Outside Air Flow per Zone Area {m3/s-m2}
0.0, !- Zone Outside Air Flow per Zone {m3/s}
HotWater, !- Reheat Coil Type
, !- Reheat Coil Availability Schedule
Reverse, !- Zone Damper Heating Action
, !- Zone Supply Plenum Name
, !- Zone Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule
autosize; !- Baseboard Heating Capacity {W}
HVACTemplate:Zone:VAV,
WEST PERIMETER, !- Zone Name
VAV with Reheat, !- Air Handling System Name
Office Thermostat, !- Thermostat Name
autosize, !- Zone Supply Air Max Flow Rate {m3/s}
, !- Zone Supply Air Sizing Factor
0.2, !- Zone Supply Air Min Flow Fraction
Flow/Person, !- Zone Outside Air Method
0.00944, !- Zone Outside Air Flow Rate per Person {m3/s}
0.0, !- Zone Outside Air Flow per Zone Area {m3/s-m2}
0.0, !- Zone Outside Air Flow per Zone {m3/s}
HotWater, !- Reheat Coil Type
, !- Reheat Coil Availability Schedule
Reverse, !- Zone Damper Heating Action
, !- Zone Supply Plenum Name
, !- Zone Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule
autosize; !- Baseboard Heating Capacity {W}
HVACTemplate:Zone:VAV,
CORE, !- Zone Name
VAV with Reheat, !- Air Handling System Name
Office Thermostat, !- Thermostat Name
autosize, !- Zone Supply Air Max Flow Rate {m3/s}
, !- Zone Supply Air Sizing Factor
0.2, !- Zone Supply Air Min Flow Fraction
Flow/Person, !- Zone Outside Air Method
0.00944, !- Zone Outside Air Flow Rate per Person {m3/s}
0.0, !- Zone Outside Air Flow per Zone Area {m3/s-m2}
0.0, !- Zone Outside Air Flow per Zone {m3/s}
HotWater, !- Reheat Coil Type
, !- Reheat Coil Availability Schedule
Reverse, !- Zone Damper Heating Action
, !- Zone Supply Plenum Name
, !- Zone Return Plenum Name
None, !- Baseboard Heating Type
, !- Baseboard Heating Availability Schedule
autosize; !- Baseboard Heating Capacity {W}
HVACTemplate:Plant:ChilledWaterLoop,
Chilled Water Plant, !- Plant Loop Name
, !- Pump Schedule
Intermittent, !- Pump Control Type
Default, !- Chiller Plant Operation Scheme Type
, !- Chiller Plant Operation Scheme Name
, !- Chilled Water Setpoint Schedule
7.22, !- Chilled Water Design Setpoint {C}
ConstantPrimaryNoSecondary, !- Chilled Water Pump Configuration
179352, !- Primary Chilled Water Pump Rated Head {Pa}
179352, !- Secondary Chilled Water Pump Rated Head {Pa}
Default, !- Condenser Plant Operation Scheme Type
, !- Condenser Plant Operation Scheme List Name
SpecifiedSetpoint, !- Condenser Water Temperature Control Type
, !- Condenser Water Setpoint Schedule
29.4, !- Condenser Water Design Setpoint {C}
179352, !- Condenser Water Pump Rated Head {Pa}
None, !- Chilled Water Setpoint Reset Type
12.2, !- Chilled Water Setpoint at Outdoor Dry Bulb Low {C}
15.6, !- Chilled Water Reset Outdoor Dry Bulb Low {C}
6.7, !- Chilled Water Setpoint at Outdoor Dry Bulb High {C}
26.7; !- Chilled Water Reset Outdoor Dry Bulb High {C}
HVACTemplate:Plant:Chiller,
Chiller 1, !- Chiller Name
ElectricReciprocatingChiller, !- Chiller Type
autosize, !- Capacity {W}
3.6, !- COP {W/W}
WaterCooled, !- Condenser Type
; !- Priority
HVACTemplate:Plant:Tower,
Tower 1, !- Tower Name
TwoSpeed, !- Tower Type
autosize, !- High-Speed Nominal Capacity {W}
autosize, !- High-Speed Fan Power {W}
autosize, !- Low-Speed Nominal Capacity {W}
autosize, !- Low-Speed Fan Power {W}
autosize, !- Free Convection Capacity {W}
; !- Priority
HVACTemplate:Plant:HotWaterLoop,
Hot Water Plant, !- Plant Loop Name
, !- Pump Schedule
Intermittent, !- Pump Control Type
Default, !- Hot Water Plant Operation Scheme Type
, !- Hot Water Plant Operation Scheme List Name
, !- Hot Water Setpoint Schedule
82, !- Hot Water Design Setpoint {C}
ConstantFlow, !- Hot Water Pump Configuration
179352, !- Hot Water Pump Rated Head {Pa}
None, !- Hot Water Setpoint Reset Type
82.2, !- Hot Water Setpoint at Outdoor Dry Bulb Low {C}
-6.7, !- Hot Water Reset Outdoor Dry Bulb Low {C}
65.6, !- Hot Water Setpoint at Outdoor Dry Bulb High {C}
10; !- Hot Water Reset Outdoor Dry Bulb High {C}
HVACTemplate:Plant:Boiler,
Boiler 1, !- Boiler Name
HotWaterBoiler, !- Boiler Type
autosize, !- Capacity {W}
0.8, !- Efficiency
NaturalGas, !- Fuel Type
; !- Priority
Output:Variable,*,Damper Position,hourly;
Output:Variable,*,Chiller Evap Heat Trans Rate,hourly;
Output:Variable,*,Chiller COP,hourly;
Output:Variable,*,Boiler Heating Output Rate,hourly;
Output:Variable,*,Tower Heat Transfer,hourly;
Output:Variable,*,Zone/Sys Air Temperature,monthly,Office Occupancy 2;
Output:Table:Monthly,
Zone Temperature Report, !- Name
2, !- DigitsAfterDecimal
Zone Mean Air Temperature, !- VariableOrMeterName01
SumOrAverage, !- AggregationType01
Zone Mean Air Temperature, !- VariableOrMeterName02
Maximum, !- AggregationType02
Zone Mean Air Temperature, !- VariableOrMeterName03
Minimum, !- AggregationType03
Zone People Number of Occupants, !- VariableOrMeterName04
HoursPositive, !- AggregationType04
Zone Mean Air Temperature, !- VariableOrMeterName05
SumOrAverageDuringHoursShown, !- AggregationType05
Zone Mean Air Temperature, !- VariableOrMeterName06
MaximumDuringHoursShown, !- AggregationType06
Zone Mean Air Temperature, !- VariableOrMeterName07
MinimumDuringHoursShown; !- AggregationType07
Instructions[LINK]
Exercise 2A. Add Unitary System with DX Cooling and Gas Heating (Furnace) Serving a Single Zone[LINK]
Objective: Learn how to describe a thermostat and unitary equipment using HVACTemplate objects.
Exercise 2B. Add VAV System with Reheat Serving Four Zones with Chiller and Boiler Plant[LINK]
Objective: Learn how to describe a VAV system with central plant using HVACTemplate objects.
Exercise 2C. Annual Simulation[LINK]
Objective: Learn how to schedule report variables and create a monthly table report.
Solution: Exercise 2[LINK]
This is a listing of new objects added in this Exercise.
Try not to look at this section until you have completed the Exercise.
Solution: Exercise 2A[LINK]
Solution: Exercise 2B[LINK]
Exercise 2C[LINK]
Documentation content copyright © 1996-2015 The Board of Trustees of the University of Illinois and the Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory. All rights reserved. EnergyPlus is a trademark of the US Department of Energy.
This documentation is made available under the EnergyPlus Open Source License v1.0.