Adding crawl space to an OpenStudio model?

asked 2015-04-15 10:34:24 -0500

dhruv
125 ●8 https://www.linkedin.c...

updated 2015-04-15 12:48:40 -0500

__AmirRoth__

4436 ●5 ●17 http://bleedinggreenna...

How do I add a crawl space to a model in OpenStudio?

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answered 2015-04-15 10:47:53 -0500

David Goldwasser

20295 ●94 ●14 http://www.openstudio.net/

updated 2015-04-15 10:48:57 -0500

From a geometry modeling perspective you would treat it like any other building space. You would add insulation to the construction of the floor of the space above and the crawl space ceiling as appropriate, and then leave the crawl space unconditioned and without any internal loads, other than infiltration, which should be included. This is very similar to approach you would take for an attic or an un-conditioned plenum.

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answered 2015-04-16 02:26:25 -0500

Julien Marrec

29087 ●87 ●74 http://www.effibem.com/

updated 2015-04-16 02:28:33 -0500

I would add to David's answer:

For ACH, around 1.0 ACH is what you're looking at¹. Maybe a bit more, but nothing extreme as long as it's passively ventilated. Anyway, it won't have a tremendous effect, as you'll see if you output the crawlspace's temperature. It does have an effect, but it's more on RH conditions in the crawlspace due to the moisture content of the air (more for condensation problems rather than energy) rather than temperature.
As far as internal loads, think about whether you have ducts and/or heating/DHW piping in there, especially if uninsulated.

¹ Joseph Lstiburek, Building Science Corporation, BSI-009: New Light In Crawlspaces