solar ray tracing

yosr

hello (very urgent), can you please help me to found a solution for my problem: i've modelled a flat plate solar energy collector, i used DO radiation model as radiation model, and solar ray tracing to calculate the illumination parameters using solar calculator, i specified the north and the east of my grid, but the problem is that i'm having any heat flux on my glass cover (the top of the collector which is oriented to the south in my case to have the best radiatif flux) thanks