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Infinite Capacity Source/Sink Not Included in EUI

asked 2016-07-20 09:27:12 -0500

Adam Hilton gravatar image

updated 2017-05-17 12:21:42 -0500

I need an infinite capacity object (that won't be factored in to the EUI in the default E+ report) to provide heating and cooling to a WSHP condenser loop. District Heating/Cooling won't work since that's included in the site EUI (which doesn't make any sense by the way since it's source energy, but I digress). I can't get the response I want from GroundHeatExchanger leaving the only other option I've found to be PlantComponent:TemperatureSource. Since this object can't be controlled by a setpoint manger I elected to created a heating and cooling primary loops that service the condenser loop through heat exchangers.

Cooling/Heating Loops (2 Unique Loops; bot with the same arragement)

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Heat Pump Loop

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Heat exchangers are set to ideal and cooling/heating setpoint modulated based on their respective loops. I've ensured all components have sufficiently large hard sized capacities.

I've tried MANY setups/combinations, but I've yet to come up with anything that responds how I'd like. Here is what the current setup yields...

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The loop works great when I a district heating/cooling setup in series. When I replace them with heat exchangers though, it all falls apart. Is there anything wrong with this setup that doesn't make any sense? Is there a better way to approach what I'm trying to do? I feel like this may be do to PlantOperationScheme:Uncontrolled, I feel like with all the explicit setpoint managers though that shouldn't be an issue.

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For one of our GSHP models we used a PlantComponent:TemperatureSource in conjunction with an EMS EnergyPlus measure to alter the schedule associated with the PlantComponent:TemperatureSource. If these is a solution you wan to try I can send some code from the EMS measure.

David Goldwasser gravatar image David Goldwasser  ( 2016-07-20 09:46:21 -0500 )edit

Absolutely, I was just starting to look into that, if you already have something operational or skeletal that would fantastic.

Adam Hilton gravatar image Adam Hilton  ( 2016-07-20 10:01:24 -0500 )edit

Does one of the combinations you tried include putting the heat pump loop heat exchangers in series on the outlet pipe? I am not sure they will get flow located inside the parallel branches with no operation scheme.

Archmage gravatar image Archmage  ( 2016-07-20 12:41:34 -0500 )edit

Ya, I thought the parallel setup would be deficient in that respect. The series setup was was the one I worked the most with. I probably should have posted a screenshot of that.

Adam Hilton gravatar image Adam Hilton  ( 2016-07-20 13:10:25 -0500 )edit

2 Answers

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answered 2016-07-20 14:36:00 -0500

Adam Hilton gravatar image

updated 2016-07-20 15:02:58 -0500

Let me preface this by saying I'm aware this is not the intended use for this object. However, I believe, this is the only option for an infinite capacity plant loop object that's not included in the default EUI reporting.

Loop Setup

  • There can't be a bypass pipe on the supply side.

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Rudimentary EMS Code

  CW_Loop_Outlet_Setpoint,              !- Name
  CW Loop Outlet,                       !- Output:Variable Index Key Name
  System Node Setpoint Temperature;     !- Output:Variable Name

  Temperature_Source_Setpoint,          !- Name
  HP-Loop-Temp-Schedule,                !- Unique Component Name
  Schedule:Year,                        !- Actuated Component Type
  Schedule Value;                       !- Actuated Component Control Type

  TemperatureSourceControl,             !- Name
  SET Temperature_Source_Setpoint = CW_Loop_Outlet_Setpoint;

  TemperatureSourceControlCall,         !- Name
  AfterPredictorAfterHVACManagers,      !- EnergyPlus Model Calling Point
  TemperatureSourceControl;             !- Program Name 1


  • Outlet Temperature = Outlet Setpoint WHEN Outlet Mass Flow > 0
  • Outlet Temperature = Inlet Temperature WHEN Outlet Mass Flow = 0

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answered 2016-07-20 23:57:23 -0500

updated 2016-07-21 06:12:20 -0500

@adhilton, this EMS code isn't too different from yours. The model this was used on has PlantComponent:TemperatureSource object on the supply side, and then cooling and heating water to air heat pumps on the demand side.

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Here is the full run section of the measure that adds EMS. Code wasn't modeling infinite capacity. You could modify this to use the ES code from your answer.

# use the built-in error checking 
if !runner.validateUserArguments(arguments(workspace), user_arguments)
  return false

# reporting initial condition of model
runner.registerInitialCondition("The building started with #{workspace.objects.size} Energy Management  objects.")

# Get the last openstudio model
model = runner.lastOpenStudioModel
if model.empty?
  runner.registerError("Could not load last OpenStudio model, cannot apply measure.")
  return false
model = model.get

plant_component_temperature_source = model.getPlantComponentTemperatureSources.first
inlet_port = plant_component_temperature_source.inletModelObject.get # todo - confirm this exists
schedule = plant_component_temperature_source.sourceTemperatureSchedule.get # todo - confirm this exists

string_objects = []

string_objects << "
  #{},                   !- Key Value
  System Node Temperature,              !- Variable Name
  Hourly;                               !- Reporting Frequency

string_objects << "
  Ground_HX_Inlet_Temp,                   !- Name
  #{},                     !- Output:Variable or Output:Meter Index Key Name
  System Node Temperature;                !- Output:Variable or Output:Meter Name

string_objects << "
  Ground_HX_Schedule_Actuator,            !- Name
  #{},                       !- Actuated Component Unique Name
  Schedule:Constant,                      !- Actuated Component Type
  Schedule Value;                         !- Actuated Component Control Type

string_objects << "
  Ground_HX,                              !- Name
  SET Tin = Ground_HX_Inlet_Temp,         !- Program Line 1
  IF Tin < 15.556,                        !- Program Line 2
  SET Tout = Tin + 5.556,                 !- Program Line 3
  ELSE,                                   !- Program Line 4
  SET Tout = Tin - 5.556,                 !- Program Line 5
  ENDIF,                                  !- Program Line 6
  SET Ground_HX_Schedule_Actuator = Tout; !- Program Line 7

string_objects << "
  Ground HX,                              !- Name
  InsideHVACSystemIterationLoop,          !- EnergyPlus Model Calling Point
  Ground_HX;                              !- Program Name 1

# add all of the strings to workspace
string_objects.each do |string_object|
  idfObject = OpenStudio::IdfObject::load(string_object)
  object = idfObject.get
  wsObject = workspace.addObject(object)

# report final condition of model
runner.registerFinalCondition("The finished started with #{workspace.objects.size} Energy Management objects.")

return true
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Awesome, thanks David. This worked with a bypass pipe too? I wonder why mine behaves strangely.

Adam Hilton gravatar image Adam Hilton  ( 2016-07-21 08:58:01 -0500 )edit

I noticed that David's model has a SPM on the outlet node of the TemperatureSource, which OS translates into a PlantEquipmentOperation:ComponentSetpoint. If you don't have an SPM on the outlet node, OS puts the TemperatureSource on a PlantEquipmentOperation:Uncontrolled. In the E+ example file, the TemperatureSource is on a PlantEquipmentOperation:CoolingLoad. @Kyle Benne maybe we should beef up the translator to put a temp source on a heating or cooling operation instead based on the Source Temperature listed in the object?

aparker gravatar image aparker  ( 2016-07-21 09:55:54 -0500 )edit

@aparker was your comment on the TemperatureSource translation ever implemented? I could not find an issue on the Github repo.

Luis Lara gravatar image Luis Lara  ( 2019-04-19 10:10:49 -0500 )edit

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Asked: 2016-07-20 09:27:12 -0500

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Last updated: Jul 21 '16