How to decide optimum tilt angle?

[atu]

I am working on a simulation model for a fixed tilt Solar PV system in East Europe.

The Solar PV rack configuration is 4x13 and the height of the lower edge of the PV rack from the ground is 800mm. Furthermore, the row distance is 7500mm.

In PVsyst, I defined all system parameters and the 3D layout model in Near Shadings part.

Finally, I simulated my model by changing only the tilt angles starting from 20 to 30 degree. According to the results, I have the highest energy yield at 21 degree tilt angle.

So the question; is my optimum tilt angle 21? Or should I perform further investigations? I am asking because, PVsyst optimization part says, my collector plane receives the highest irradiation at 30 degree but at the same time the shading losses increase. On the other hand for 21 degree tilt angle my irradiation on collector plane is less in parallel with the shading losses.

When I review loss diagram, the major difference is at "Shadings: Electrical losses according to the strings" parameter.

I would appreciate, if one can explain, how to choose the right tilt angle.

Will be waiting for your kind support.

Thanks,

Alper

[dtarin]

That is generally true during optimizations. Higher tilt will result in higher shading losses. The other factor to take into account is snow losses if your site experiences snow, as a higher tilt will result in lower snow losses.

But in general, yes, you will see shading losses outweigh the irradiance gain from increasing the tilt, although I wouldnt rely on the PVsyst optimization, and actually run the simulation at the different tilts to find exact result. The optimizations can be a good starting point for analysis.