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Plenums and ceiling heights

asked 2015-03-18 11:29:35 -0500

Carlos Vazquez gravatar image

updated 2015-07-10 21:22:35 -0500

There is one video showing how to model plenums in openstudio. However, is there a way to just specify ceiling heights in openstudio?

I was looking at the idf editor in energy plus and is possible to specify a ceiling height per zone. Also the manual says that ceiling height can be "heuristically calculated" in energyplus. Can somebody give me a hint or clarify for me how this works?

Thank you.

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answered 2015-03-18 23:10:31 -0500

updated 2015-03-19 08:23:01 -0500

The OpenStudio GUI doesn't expose the manual fields for a thermal zone like height, area, or volume. We typically rely on EnergyPlus to autocalculate it. These fields are exposed in the API as shown here, but you would have to use a measure. You would also have to be careful if space loads were per area or related to volume like airflow, that the space still had accurate geometry to calculate the correct internal loads.

If you are making a new model you can set the desired height by using the spaces from diagram tool in the SketchUp plugin or use a measure like the Bar Aspect Ratio measure.

If you're model already exists and you want to edit it by editing the space geometry , some possible solutions (measure based and plugin based) are described on this thread.

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Thank you for your help David! I am making some test models to develop a workflow for my cases. I found that the inspector tool in openstudio has a ceiling height field when thermal zones are created from one or more spaces. Would this be a more straight forward way to specify ceiling heights?

Carlos Vazquez gravatar image Carlos Vazquez  ( 2015-03-31 00:59:55 -0500 )edit

If you change the height field, looking at the EnergyPlus documentation it might change how EnergyPlus calculates the zone volume, however you will get a warning that it isn't close the the auto-calculated height. This is a valid warning because the exterior exposed geometry for the model won't reflect what you would have with the increased ceiling height.

David Goldwasser gravatar image David Goldwasser  ( 2015-03-31 10:31:00 -0500 )edit

if we have the warning and the exposed geometry for the model won't reflect the change, while other internal loads are area based calculated, so if I change the plenum/height; the load calculation won't be changed? Thank you David

Brianna gravatar image Brianna  ( 2021-04-14 20:11:50 -0500 )edit

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Asked: 2015-03-18 11:29:35 -0500

Seen: 344 times

Last updated: Mar 19 '15