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Error Warning: "CalculateZoneVolume: 3 zones are not fully enclosed" Does this have a large impact on on space heating and cooling loads? [closed]

asked 2021-07-09 09:39:13 -0500

Ross B. gravatar image

updated 2021-07-09 16:23:24 -0500

Hi All,

Looking at the passive solar heat gain of a structure and just wondering if the warning mentioned above will have a large impact on space heating or cooling.

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Closed for the following reason the question is answered, right answer was accepted by Ross B.
close date 2021-07-12 14:45:06.892886

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It's hard to know, it could be trivial or could be a huge problem. You should certainly look at geometry and identify what causes this and if you can fix it. If you don't fix it you should look at the reported floor area and volume and see if it is what you expect.

David Goldwasser gravatar image David Goldwasser  ( 2021-07-09 11:58:57 -0500 )edit
1

If an envelope element does not exist where it should (i.e., you are missing a wall), lack of thermal mass and radiation/convection provided by that wall element to the zone air would also impact load balance. See @shorowit's reply below: leaving a gap in the enclosure does not result in infiltration. If you are using OpenStudio to generate your IDF you should look in the Geometry tab; I think there is a way to render by constructions, boundary conditions etc. (see https://www.youtube.com/watch?app=des...)

sashadf1 gravatar image sashadf1  ( 2021-07-09 13:46:45 -0500 )edit
1

I suggest an empirical test: Enter very different values for the Zone: Volume field and see how sensitive the results are.

shorowit gravatar image shorowit  ( 2021-07-09 15:44:49 -0500 )edit
1

@sashadf1 That's not how EnergyPlus (nor DOE-2 or many other similar engines) works. A "missing" surface does not mean you have a hole in your building that brings in infiltration. You can absolutely run EnergyPlus without fully enclosed surfaces, we do it all the time.

shorowit gravatar image shorowit  ( 2021-07-09 15:47:32 -0500 )edit

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answered 2021-07-09 15:55:37 -0500

If you add "Output:Diagnostics,DisplayExtrawarnings" to your input file you can usually get enough information to diagnose the problem. Often the problem is just edges of surfaces that are not lined up. Generally, you should confirm if the zone volume being used in the simulation is what you expect. If it is then it is not a problem. The zone volume is only used in a few places related to airflow. Also note, the algorithm that determines if the volume is not enclosed is not full proof and sometimes shows something is wrong when it is not.

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Thanks for the many responses, the program is defaulting to my my entered zone volume rather than calculated. The energy demands make sense given the values I am getting when calculated with other software.

Ross B. gravatar image Ross B.  ( 2021-07-12 08:31:14 -0500 )edit

 

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Asked: 2021-07-09 09:39:13 -0500

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Last updated: Jul 09