How to model window/opening for natural ventilation

asked 2018-04-18 19:15:04 -0600

Ery Djunaedy
355 ●2 ●7

updated 2018-04-19 10:17:49 -0600

I am trying model various window/opening for natural ventilation as commonly used in the tropics. Below as some examples on the openings I am trying to model.

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In EnergyPlus, various openings are represented as opening factor and a discharge coefficient. What I want to come up with is a list of openings commonly used in the tropics and provide a way to model it (i.e. what is the opening factor and what is the discharge coefficient).

My questions:

Anybody knows if such a list exists? I have come up with a few openings myself and would like something as a comparison.
How to validate this kind of model? The models that I have defined seems to give a high flowrate. I would like to have some kind of validation for this. Anybody knows if such a validation study have been performed before? Or is there any other measurement data that I can use?

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answered 2018-04-19 11:55:49 -0600

Jason DeGraw

2208 ●6 ●10 https://github.com/jasondegraw

There are a few lists out there, including in old ASHRAE handbooks, but those can be hard to find. The best resource that I know of is for NIST's CONTAM software here. Some caveats, though: most of that data is going to be for closed doors and windows and it's in the form needed for use with CONTAM. Some work will be needed to use the data in EnergyPlus. There are references to source data at the NIST link, so you can dig in deeper and get more information.

Validation is pretty difficult. You can use CFD or do measurements, but neither of those is necessarily very easy to do. Studies have been done, but the problem is likely to be that unless you're lucky enough to find work that uses exactly your window type(s) it won't be directly applicable. Searching via Google for "natural ventilation rate window" turned up a large number of results, I'd expect similar results in any of the literature search engines. Even if you can't find exactly what you want, you should be able to find similar enough windows that it'll give you an idea of what reasonable values are.