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GSHP Unable to provide Heat Rejection enough capacity in E+

asked 2021-06-12 09:30:04 -0600

updated 2021-06-22 10:25:41 -0600


I am trying to model an "Autosize" GSHP model for a group of residential buildings which are in the schematic stage of design. I tried to follow some of the example files and other online resources to set this up. The heating loads and temperatures are working fine but in the cooling mode the demand is meet for few days and rest of the time the outlet temp serving the Low temp Radiant system from the WSHP steadily goes up from the expected 18degC to 30 degC OR WSHP stopped working, Refer attached file C:\fakepath\2021-06-13_10h45_31.png. I also replaced the GHX with a cooling tower and it works fine which gives a hint that the problem could be at the GHX side. Is there any parameter which could affect the cooling capacity/demands directly under GHX objects for an "Autosize" setup?

Thank you,

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@Javed what simulation tool are you using? Please mention the tool in your title, question, or add a tag so that others can provide better solutions.

Aaron Boranian gravatar image Aaron Boranian  ( 2021-06-12 15:08:04 -0600 )edit

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answered 2021-07-07 05:35:53 -0600


I was able to solve the issue with the help of some pointers from simulation experts (Mr. Jim Dirkes specifically). It was a complex mechanical arrangement where a couple of "Heat Exchangers" were modeled to have multiple loops to supply heating/cooling at different temperatures. Since everything was autosize somehow these capacity issues arose as highlighted in my original post. Simplifying the mechanical arrangement in a step-by-step manner leads to fixing the issue. I have never encountered such issues in a "Autosize" model but this time it happened AND I don't know the exact cause of this. However it got resolved by bringing a basic ingredient, "simplicity" in the model.

Hope this will be helpful to others.


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Asked: 2021-06-12 09:30:04 -0600

Seen: 87 times

Last updated: Jul 07 '21