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Some beginner's doubts

asked 2023-04-03 04:26:30 -0500

Pablocm's avatar

updated 2023-04-03 09:40:47 -0500

Hello, I am a student of a Spanish university who is doing a TFG on the energy saving by placing a heat pump that takes advantage of geothermal energy. For this analysis I am using Open Studio but I am new with the program and I have some doubts.

The structure, thermal zones and spaces have been made through sketchup and then I exported the file to Open Studio. I have not yet introduced any HVAC system because I had many more errors.
In the errors that I have listed below. I don't know where is in the open studio the section where to place the temperatures of the ground (i know how to do it in energy plus but not in Open studio ).
The failures of ''always off discrete and always on continuous'' I don't know exactly what they are caused by

Sorry for the inconvenience

Best regards, Pablo

Here are the errors:

** Warning ** ProcessScheduleInput: Schedule:Constant="ALWAYS OFF DISCRETE", Blank Schedule Type Limits Name input -- will not be validated.
** Warning ** ProcessScheduleInput: Schedule:Constant="ALWAYS ON CONTINUOUS", Blank Schedule Type Limits Name input -- will not be validated.
** Warning ** GetHTSurfaceData: Surfaces with interface to Ground found but no "Ground Temperatures" were input.

Thank you

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answered 2023-04-03 14:52:13 -0500

The warnings (not errors) you're getting are not unusual. A few basic schedules do get added when OpenStudio forward translates your model to EnergyPlus. You can check for these by comparing in.osm vs in.idf files under the run folder (using a text editor). Slightly annoying (we'd all like to see 0 warnings), yet usually not an issue.

Unless this has changed with the latest release, OpenStudio Application users cannot set ground temperatures (see here). That link provides a few suggestions to counter this limitation (including switching to KIVA), but you may be able to simply copy/paste something like the following directly in your OSM:

OS:Site:GroundTemperature:BuildingSurface,
  {f904478f-7d4c-4665-bc6f-f6798a5ea52f}, !- Handle
  13.02,                                  !- January Ground Temperature {C}
  12.94,                                  !- February Ground Temperature {C}
  12.92,                                  !- March Ground Temperature {C}
  18.03,                                  !- April Ground Temperature {C}
  22.41,                                  !- May Ground Temperature {C}
  26.33,                                  !- June Ground Temperature {C}
  26.64,                                  !- July Ground Temperature {C}
  25.84,                                  !- August Ground Temperature {C}
  23.47,                                  !- September Ground Temperature {C}
  18.98,                                  !- October Ground Temperature {C}
  13.86,                                  !- November Ground Temperature {C}
  13.19;                                  !- December Ground Temperature {C}

Adjust the temperatures based on your EPW.

It's usually discouraged to add OpenStudio objects with unique handles this way, but Site objects are pretty high up the model object hierarchy. Still, maybe safer to first try on a copy of the model.

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Understood, thank you very much for your reply

Best regards, Pablo

Pablocm's avatar Pablocm  ( 2023-04-04 08:53:12 -0500 )edit
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answered 2023-04-05 11:04:24 -0500

I’ve always the same warnings “Always On.. Off..” even if these schedules are not introduced but the models run perfectly without any problem. I’ve written an OS measure to introduce ground temperatures in the idf

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Asked: 2023-04-03 04:26:30 -0500

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Last updated: Apr 17 '23