How is near shading irradience losses caclulated?

[Lima]

why is the near shadings for a tracker system with 13 degrees and a minimum above ground of 2.1m has 0.3%  near shadings and that of 60 degrees and 0.5m above ground has almost around 3%? How does pvsyst calculate this?

[Michele Oliosi]

The minimum height above ground is not very relevant to the near shadings.

If your trackers go to 60° rotation angles:
- it means they will follow the sun much lower than the 13° ones, inducing more mutual shadings if backtracking is not active
- the diffuse component is also subject to more mutual shadings

 

 

[Lima]

What is then difference between near shadings and electrical string shadings?

[Michele Oliosi]

near shadings : irradiance loss

electrical shadings : electrical mismatch loss caused by partial shadings