Ah, modeling trees in building energy simulations.
What I've done (with DOE-2, but it's equally doable in EnergyPlus) is to model them as five BUILDING-SHADES making up a box, and give the shades a transmittance schedule depending on when the leaves fall. The second slide in the attached PPT is from an ASHRAE presentation I gave in Dallas two weeks ago that happened to have some trees modeled around a house. The only thing to watch out for, in my case at least, was to set the transmissivity at the square root of the intended value, since the solar radiation always passed through two building shades. If building-shades in EnergyPlus are one-way, then I guess even this detail is unnecessary.
If you're not satisfied with how clunky a square tree looks, you can also input polygons to make a sphere. About ten years ago, I wrote some awk scripts to do that for modeling building domes in Egypt, that I reported in DOE-2 User News Sept-Oct 2002 (see second slide attached). Of course the script just does the top hemisphere, but extending it below shouldn't be a problem. The article is available at www.whiteboxtechnologies.com/downloads/02_09_Usr_News_YJH_modeling_domes.pdf , which contains the awk script. If anyone tries to modify it, like putting it in another language, outputting the vertices in E+ IDF format, doing the lower hemisphere, etc., let me know how it turns out.
Joe Huang White Box Technologies, Inc. 346 Rheem Blvd., Suite 108D Moraga CA 94556 yjhuang@xxxxxxxxxxxxxxxxxxxxxxxx www.whiteboxtechnologies.com (o) (925)388-0265 (c) (510)928-2683 "building energy simulations at your fingertips"
On 2/14/2013 2:51 AM, Fabiano Domingues Ferreira wrote:
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