Near shading loss without 3D shading scene

[ClaireWest]

Why is there a near shading loss for a single-axis tracking system with backtracking, when there is no 3D shading scene? The backtracking should prevent any self-shading and there are no objects or terrain modelled to cause other near shadings. 

TIA

Edited November 27 by ClaireWest

[Robin Vincent]

The backtracking strategy avoids direct mutual shadings, but not the other irradiance components.

If you extract the simulation results with all the near shadings variables, you should be able to see that the Beam loss due to near shadings (ShdBLss) are equal to 0, but not the diffuse (ShdDLss) and albedo (ShdALss) components.

[ClaireWest]

Thanks. What simulation parameters influence these losses? e.g. diffuse irradiance (total amount or fraction), GCR, albedo, etc?

[Robin Vincent]

With unlimited sheds, pretty much all the parameters you mentioned will impact the near shadings losses.

 

You may be able to find more detailed information in the help page for diffuse losses with tracking systems :

https://www.pvsyst.com/help/project-design/shadings/calculation-and-model/diffuse-losses-with-tracking-systems.html#tracker-diffuse-shading-definition-window-from-version-730