Delete plenum from existing model

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Hi Users

I am facing a challenge in deleting the plenum from each floor of the
building. Initially, I have created a building with Flr to Ceil height of
9ft and Ceil to Flr height 4ft. Know I have to delete the plenum from each
floor, in this process I have increased the Flr to Ceil height to 13ft,
then tried to delete the plenum walls for each zone. After that, I am
trying to delete the plenum space but the "Next to the surface" of the
ceiling is which is selected as plenum are creating an error.

Please let me know the way to delete the plenum in detailed mode.

Thank you
Regards

Shashank Mishra's picture
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Joined: 2019-12-11
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Hi Shashank,
You can make the INT-WALL-TYPE of the ceiling surfaces ADIABATIC (no heat transfer across the surface) which eliminates the requirement for the NEXT-TO keyword.
A second option that may be easier is to copy your model and make the change in the Wizard mode. Once you take the revised model into DD Edit mode, you can open the input files of each model and copy the entire spaces section of the revised model into the other model. There?s more work to it though if you have already made many changes to loads in the spaces, as those changes are lost when you revert to Wizard mode and you?ll have to reenter them or copy them from the earlier model.
Regards,
~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer

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Bill Bishop's picture
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Great advice from Bill, per usual.

I?ll add an ?ugly? option that could be the most time-efficient if care more about simulation accuracy than aesthetics:

In the case of plenums, you could consider the end game of just leaving them in the model. It might make your 3D views look a little funny, but if you?ve already fixed your actual space volumes by adjusting their height, the remaining tweak is to either mindfully switch those spaces? ceiling NEXT-TO relationships up so that heat is transferred between floor spaces (or just switch to adiabatic if you can assert such heat transfer is acceptable to not simulate, which is a fair assertion if the spaces above/below do not normally feature a substantial delta-T and you?re happy with the idea of well-mixed volumes). Swap any air-side return air path inputs from plenum to ?direct? if that?s the case, and I think you?re done.

The only other thing I can think of to look out for is to ensure no (subsequently modified) windows end up with geometries inadvertently shaded by overlapping exterior surfaces remaining from the plenums. If that?s a likely outcome I?d probably take Bill?s advice and proceed with something that would just delete the plenums from my model to simplify things.

~Nick
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