Relation between far shadings and modules tilt angle

[stesigno]

Hi everyone,

I have simulated a 1 MWp PV plant composed by different rows with PVsyst 5.71, after having introduced horizon profile and near shadings.

While it's simple to understand geometrically mutual shadings increasement with higher tilt angles, I can't explain why, increasing the modules tilt angle from 14° to 34°, far shading losses increase from 1,60% to 3,20%.

Thank you, best regards.

Stefano

[André Mermoud]

The far shading losses are indeed depending on plane tilt.

When the modules are at low tilt, the losses arise with a higher incident angle, and the loss applies to a lower beam irradiance amount (due to cosine effect).

With a high tilt, the shades apply with a lower incidence angle, when the sun's rays are more perpendicular.

For understanding this intuitively, you can take the exrtreme cases of an horizontal plane (which "sees" the horizon line quite marginally) and a vertical plane, which will be affected by low sun's height, when it should be very well irradiated.