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How to use the temperature difference between outdoor and indoor air to reset Ideal Loads Setpoints in Energyplus

asked 2015-12-09 10:41:05 -0500

Jevin gravatar image

updated 2015-12-09 12:27:53 -0500

Using Energyplus for modelling a residential house.

My aim is to reduce energy consumption by varying various parameters of the building. My comfort model is a new relation between outdoor and indoor temperature. I have set up my Airflow network for modelling natural ventilation. Since I am only concerned with the energy use for cooling and heating I'm using Ideal Loads to provide cooling and heating.

Now I would like to set-up my cooling and heating set points to be modified according to the temperature differences.

Any recommendations?

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answered 2015-12-10 16:07:21 -0500

updated 2015-12-10 16:08:53 -0500

Use a simple EnergyPlus EMS Program

You'll need:

  1. A sensor that reads the outdoor air temperature
  2. A sensor that reads the zone mean air temperature
  3. An actuator that controls the cooling temperature setpoint schedule
  4. An actuator that controls the heating temperature setpoint schedule
  5. A program control object, probably set to run
  6. A program object that reads the two sensors and modifies the setpoint schedule via actuator

```

EnergyManagementSystem:Sensor,
  OutdoorTempC,                      !- Name
  Site,          !- Output:Variable or Output:Meter Index Key Name
  Site Outdoor Air Drybulb Temperature;  !- Output:Variable or Output:Meter Name    

EnergyManagementSystem:Sensor,
  ZoneTempC,                      !- Name
  My_Zone_Name,          !- Output:Variable or Output:Meter Index Key Name
  Zone Mean Air Temperature;  !- Output:Variable or Output:Meter Name

EnergyManagementSystem:Actuator,
  HtgSetPtSchAct,           !- Name
  Heating_Schedule_Name,             !- Actuated Component Unique Name
  Schedule:Compact,       !- Actuated Component Type
  Schedule Value;          !- Actuated Component Control Type

EnergyManagementSystem:Actuator,
  ClgSetPtSchAct,           !- Name
  Cooling_Schedule_Name,             !- Actuated Component Unique Name
  Schedule:Compact,       !- Actuated Component Type
  Schedule Value;          !- Actuated Component Control Type

EnergyManagementSystem:ProgramCallingManager,
  ChangeSetpointsProgramManager,  !- Name
  BeginTimestepBeforePredictor,  !- EnergyPlus Model Calling Point
  ChangeSetpointsProgram;  !- Program Name 1

EnergyManagementSystem:Program,
  ChangeSetpointsProgram,  !- Name
  ...Logic goes here...
  SET HtgSetPtSchAct = whatever,
  SET ClgSetPtSchAct = whatever;
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answered 2015-12-13 04:46:54 -0500

Jevin gravatar image

updated 2015-12-14 07:11:15 -0500

@aparker, Thank you very much. Thanks exactly what i did but somehow there seems to be a problem with the model.

The Schedule Compact changes hourly.

When i set my timestep to 1 per hour it works fine with the set points changing accordingly but when i increase the time steps it seems that the program doesnt know what to do during the intervals.

any advice?

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Asked: 2015-12-09 10:41:05 -0500

Seen: 847 times

Last updated: Dec 14 '15