3D scene with bifacial - Azimuth values (0°, 180°) and impact on results

[cecile]

Dear PVsyst team,

While I was simulating a bifacial project with bifacial on a flat field (Chile, south hemisphere), while designing the scene, I changed the azimuth value and I realized that the GPOA rear changed significantly thus the yield results too. I identified the losses in yellow below.

I could not explain this behavior as the project is designed on a flat terrain thus changing the azimuth from 0° to 180° should not have any impact as the project is symmetric.

I suppose the correct simulation is the one with “azimuth 0” but cannot explain why the gain called “beam effective on the rear side” goes from +113.45% from one simulation to 0% for the other simulation. Could you help me to understand this behavior and tell me what gain could be realistic for this simulation?

To what criteria the beam effective on the rear side is sensitive to (design characteristics, irradiation or ground characteristics) ?

Recoleta-SG-TMY-for PVsyst team.zip

PVsyst files

Losses affected by azimuth change

[André Mermoud]

This was indeed a bug, that we have fixed but not yet published.

Please don't use the axis orientation around 180°.