Bifacial Gain dependency on bifaciality factor SAM 2020.11.29

Hello,

I just started simulating bifacial systems with the latest version of SAM (2020.11.29). Before I was working with an older version (2018.11.11).
At first I wanted to compare both and for that I simulated the same PV array in both versions. I got different values for the POA bifacial irradiance, higher values for the new version, which makes sense to me. But then, I started to change some parameters to better understand the program and realized that the value of the bifacial gain is modified, as expected, when I vary values like GCR, module height, albedo, but strangely it remains constant when varying the bifaciality factor in the module datasheet. It is important to note that this did not happen in the previous version.
Do you know what can happen? As I understand the bifaciality is an important data to estimate the bifacial gain.
Thanks in advance for your support and sorry for the basic question.

Regards

Hi Franco,

The bifaciality input determines the efficiency of the photovoltaic cells on the rear side of the module: The cells on the rear side of a bifacial module are usually not as efficient as the cells on the front side of the module. The bifaciality does not affect the amount of solar energy that reaches the back of the module, so it does not affect the rear-side bifacial gain. It does, however affect the amount of electricity generated by the array as you can see in the parametric results below from SAM 2020.11.29.



Best regards,
Paul.