Comparison between AnnualRadRecipe and AnnualDLRecipe


I am doing a radiation study in order to check the potential gain of using bifacial PV panels. I started with a very basic case with 3 rows of PV panels in front of a facade. I used 1 test point in the center of the middle PV panel and I did radiation simulations for the front and back side of the PV panel.

I was trying out AnnualRadRecipe and AnnualDLRecipe (with analysis type set to radiation). For the front side of the PV panel, I got similar results using both components. For the back side though, the results are very different. I made some annual charts to compare the simulation results.

What do you think about the results? The results of the back side from AnnualDLRecipe seems more logical to me. Did I make a mistake in my grasshopper file? What is the exact difference between using AnnualRadRecipe and AnnualDLRecipe?

Thanks a lot!

bifacial (627.8 KB)