Predicting Patch-based diffuse Irradiance values

Dear All,

I wanted to ask a question related to the prediction of the diffuse horizontal (or vertical contribution) of a particular patch of the sky ( with a specific patch altitude, solid angle, patch azimuth).

I am developing a patch-based Irradiance model and I wanted to compare with other models in Radiance , e.g.Perez Model. I know How to calculate the diffuse horizontal, or any titled surface of the whole sky, but in my case I wanted to compare in a patch-based mode. So I need to simulate a patch-based contribution of diffuse component in horizontal or any titled surface.

I thank you in advance,

Regards,

Sokol

Dr. techn. Sokol Dervishi

Department of Building Physics and Building Ecology
Technische Universit├Ąt Wien
Karlsplatz 13, A-1040 Wien