Inconsistent Soiling loss

[MicheleANE]

Hi,

I was doing several simulations of the same project using GHI data measured on site on a monthly base and only changing the soiling setting and I noticed an inconsistency in the resulting loss.

In some months the measured soiling loss was under 0.1% (ex.: 0.06) and without any visible reason the resulting loss becomes 0.1% or 0%.

This doesn't even depend on the input number being over 0.05% or not. I had some months with 0.02% setting giving 0.1% loss in the diagram.

I understand this is a very little difference but I have no explanation to give customers when asked for.

The best solution would actually be to just use the setting number as it is without rounding, both in the settings report and in the loss diagram.

Thanks in advance for your time and best regards.

Michele

[André Mermoud]

This is indeed a rounding effect.

I don't know how you have evaluated your values, but we consider that errors lower than 0.1% on a specific month is completely insignificant.

 

 

[MicheleANE]

Thank you for the prompt response.

I understand that the effect is very low. The problem is the consistency of the rounding. It would be fine if it always rounded to 0% or as normally if >0.05 then 0.1, if<0.05 then 0 or also always to 0.1

Also I don't really see the need of rounding these numbers. Wouldn't be even easier to just keep them as they were input?

Sorry for being pedantic but we were asked this by customers and we are not able to give them an answer.

Best regards