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Re: [EnergyPlus_Support] sky luminance

Hi  Linda:
Of course, because there are not enough studies to quantify the sky type recognization, it is not easy to convert new models into code now.
if EPlus code changed the model of its reference, its prediction may be unreliable if without prior validation of new models. In that page, EPlus cited the reference where the model appears, it is probably that EPlus follows the approach of its reference. Hope to check it out and make it clear.

On Wed, Feb 3, 2010 at 8:51 AM, Linda Lawrie <linda@xxxxxxxxxxxxxx> wrote:

A new sky luminance model is not in the enhancement list queue. 

If you were a collaborative developer, you could develop one and submit it to the team for potential inclusion.

Many times there will be changes when one takes a reference idea and has to fit it into code.  As code is not provided by references (nor have they stood test of time).

Why would the sky model need to be changed?

At 10:52 PM 2/2/2010, Hu,Jia wrote:
After reading one orginal ref. of Eng. Ref . I feel  some inconsistency maybe exists between Eng.Ref. and original source.
In Page 152 (PDF 191), it interpolates the two sky luminance distributions, but in its reference, Perez (1990)  interpolated the "geometrical factor ", which is the ratio of sky luminance distribution to Zenith luminance. In different sky types, Zenith luminance is different even if sky conditions are the same
I do not know how EPlus actually works in this case. if it follows the Engineering Ref. some errors may occur. But it probably follows the method of the reference.
Many other sky models are developed now.  is it possible to update the sky luminance distribution model in EPlus?


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