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Equest - Deleting Plenum Thermal Zones

asked 2020-05-04 11:13:51 -0500

Tanvi gravatar image

updated 2020-05-04 17:37:39 -0500


I am using equest for the first time, working on a eight storey Library Building with approximately 750 zones (including plenums) and different HVAC systems. The model has multiple plenum spaces and zones allotted to each space. I started deleting few of the thermal plenum zones (for unconditioned utility areas) and the spaces started disappearing, in all the previous versions as well. Eventually, the spaces deleted from all the previous versions as well. Height of the wall is whole floor to floor height, editing that is not fixing the problem.

Please let me know how do I fix this. Thank you.


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answered 2020-05-05 08:43:24 -0500


Not sure I fully follow the question, but the main issue appears to be when deleting a thermal zone the space disappears, yes? A key understanding within eQuest/DOE is that thermal zones __are__ spaces; this is different than OpenStudio where there can be multiple spaces assigned to a thermal zone. While they are defined separately in the input; zones & spaces have a 1-to-1 relationship within eQuest.

Backing up, I would question first if these zones actually need to be deleted. If their 'unconditioned' then set them to 'unconditioned' and move them to a nearby HVAC system. They wont receive any conditioning (being unconditioned), but the thermal zone will still transfer heat to/from adjacent zones. Any concerns about extra/fake/non-existent plenums may be overblown. If its an unconditioned zone with an unconditioned plenum, set them to unconditioned & be done with it. Can change the ceiling construction to 'air wall' if concerned about any temperature delta between the two or other adjacent zones.

Extensive geometry modifications post-wizard is not for the faint of heart; polygon modifications are hard & I advocate avoid if at all possible. It's tedious and can corrupt a model if done wrong. This is not wall height or floor-to-floor, thats straightforward enough.

Let us know if this is/was the right understanding of the question.

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Thank you for the solution. I considered the ceiling as air wall, but It had an error "ceiling has no heat capacity". As the airwall has no certain property the U-Value is zero and thus cannot simulate further.

Tanvi gravatar imageTanvi ( 2020-05-11 04:56:16 -0500 )edit

@Tanvi are you saying the model crashes/simulation wont complete or concerned about a warning in the SIM file output? Are you using the 'default air wall' from the library? It should have a U-value of 2.7 btu/h-ft2-F; not 0. Verify library construction is used. Not sure what you mean by 'no certain property'; can you further define that? I've used this air floor/air ceiling method many times with no crashing of the simulation. A common issue i have seen with this method is that the adjacency must be set properly (the 'Next to:" property). Otherwise the wall will be adiabatic.

dradair gravatar imagedradair ( 2020-05-11 08:19:26 -0500 )edit

Yes, Sorry issue resolved. The construction was layered, so it had an issue. Thank you.

Can you please solve one more query?

I am trying to add window to the interior wall, as its a office glass partition. But it is giving me error as "structure cannot be in interior window" ...I created a child component (window) in internal wall, or should it be door?

Tanvi gravatar imageTanvi ( 2020-05-12 02:08:10 -0500 )edit

Saw this was a separate, but deleted question. Moderators may close & ask you to make separate question

depends on the goal of what you're trying to accomplish.

If the goal is to reflect the thermodynamics of having a glazed interior wall; that is possible. Have to create in 'interior glazing' Material from 'Spandrel glazing' library object, create layers & construction. But possible. (New material, as was getting error that default 1/4" was to light to sim).

If the goal is to have daylight pass thru a zone to another, that isn't possible i believe.

dradair gravatar imagedradair ( 2020-05-12 10:24:38 -0500 )edit

Yes, I was trying with sun-space and interior window method. Although its getting complicated as well. My goal is to reflect the thermodynamic difference caused by the solar gains. I will try with spandrel glazing material. Thank you.

Tanvi gravatar imageTanvi ( 2020-05-12 10:30:36 -0500 )edit

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Asked: 2020-05-04 11:13:51 -0500

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Last updated: May 05