Difference in IAM factor global in different versions

[sarika]

Hello,

I am working on a PVsyst simulation for a on grid PV plant. I have noticed differences across values for the IAM factor global for different versions of PVsyst.

In version 6.4.1, its positive, +2% (a gain). In version 6.4.7, its negative, -2.4% (loss). Cumulatively its an effect of >4%.

All the details of the project are the same. The IAM profile is provided by the manufacturer which is the same in both versions.

Can you explain me what factors are responsible for such a difference?

Which verison is more reliable?

Thanks a lot,

Sarika

[André Mermoud]

There was indeed an error when reading the IAM parameters (when defined as a profile) in the version 6.41.

This has been corrected in the next versions (since 6.42).

[sarika]

Dear André Mermoud,

Thanks for the reply.

Does that mean that we can consider the ASHRAE value for the calculation then? There is no error with that?

We can't update to the new version right now.

Regards,

Sarika

[André Mermoud]

No, there was no problem with the ASHRAE standard.