Hi everybody, I’m analyzing the illuminance level of a simple rectangular space covered with horizontal louvered panels. The panels can be rotated for 90 degrees in order to adjust the amount of interior light during the day. I tried to optimize the amount of interior Lux (specifically between 50 to 300 lux, in my case) by finding the optimum angle of the panels. At the end of optimization I draw the graph of the results in excel but the outcome was very strange.

The graph shows the illuminance level inside the building for the entire day (the panels are constant). If you have a look at it, the result changes suddenly at 2pm which is not logical for me at all.

I would be so pleased if anyone could possibly help me with this issue??