Factors affect irradiance loss

[uncleaux]

 

Hi, why do solar panels mounted at different building heights produce varying outputs, even if the number of panels is the same? From my observations, it seems to be due to irradiance loss. What factors contribute to this?

10 Storeys

30 Storeys

[uncleaux]

Additionally, when I used a fixed-tilt setup instead of a two-axis tracking frame (E-W with 90° min and max tilt and 0° min and max Phi), the output was significantly lower. What are the reasons for this?

[Michele Oliosi]

EW trackers here can follow the sun closely in the morning and evening. Instead, fixed tilt does not have a good orientation in the morning and evening.

[Michele Oliosi]

In your top question, the shadings are not exactly the same. Are you using the fast (relying on interpolations, which are sensitive to tiny rounding differences) or slow method ?

[uncleaux]

Hi Michele,

I used the slow method in the simulation, and I think I've found the problem. The dual-axis frame, which is supposed to be fixed, rotates on its own after I updated from version 7.4.0 to 7.4.7.

By the way, what could cause the global incident value in the collection plan to be negative? Also, why might the output from the tracking vertical or tracking sun shield have a lower value than a fixed tilted plane? Even if I fixed the tracking vertical, the value is also lower than the fixed tilted plane. The plane tilt for the tracking vertical and fixed tilted plane is set at 90°. 

[Michele Oliosi]

The Global incident will be negative if the orientation is worse than the horizontal fixed plane. I am not sure why, just from your text. Indeed, in principle, trackers should have a better transposition than a fixed plane.
It is difficult to answer just from the loss diagram and 3D screenshots. Could you export your project and send it to support@pvsyst.com ?

[uncleaux]

Alright, thank you, Michele.