Jump to content

Simulation with vertical panels (tilt 90º)


Recommended Posts

Hi, I’m working in a project with vertical panels (tilt = 90º) and an orientation E-W (-90º). I realized some problems when working with that configuration in PVsyst:

- The performance ratio is over 100 % : I find performance ratios around 120-145 % which should be impossible as the theorical maximum performance ratio of a panel is 100 %.

- I run a test with a near shading scene where I have only one tree and only one table of panels. If I put my table at the west of the tree, I have near shading losses of around 30 %, but if I put it at the same distance but at the east I have only 2 % of irradiance losses, which doesn’t make any sense. I think that the losses should be quite similar in both cases. My system is a bifacial one, so the panel is supposed to produce electricity from both sides, and I think that PVsyst is only considering the irradiance arriving on one side.

Thank you for your answer.



Link to comment
Share on other sites


The bifacial model only considers mutual shadings due to the geometric arrangement of the PV tables, and not the shadings extracted from the 3D scene. The 3D scene only affects the front side. This is due to the analytic nature of the bifacial model, that works under the assumption of regular rows of tables or trackers.

The performance ratio used by PVsyst is the standard one, i.e. normalized to the frontside POA irradiance, please see https://www.pvsyst.com/help/performance_ratio.htm for its definition. This is why it can be above 100% for bifacial systems.

Link to comment
Share on other sites

Correct me if I am wrong, but you can manually calculate the correct PR by including the rear-side irradiance. For a vertical system, this is necessary since the rear-irradiance contribution is significant, and you will likely have irradiance instrumentation on both sides of the module in a constructed facility.
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...