adrie

The above statement is found in the optimizer documentation. I there any documentation of this model? How are the values of the model parameters determined?

It is healthier to take a break from PVsyst once in a while. :)

It goes to DEMO mode. :cry:

What happens after you dismiss the warnings?

Ok, so PVsyst keeps the three copies of the SIT contents in sync with each other. I guess ultimately I wanted to understand the reason for storing these SIT details three times. If they are simply always kept in sync, then it doesn't seem be done to address a user need. Perhaps it just made life easier for the program/programmer to do it this way? :)

Thanks for responding! Let's talk about the SIT file first, since that is what I was originally asking about. The other day I deleted one, and my simulation still ran. Is it right to conclude that it is no longer required? This seems to contradict your observations though...

This question has been unanswered for almost two years, but actually it would still be useful to have an answer...

No, still waiting.

The help file states: What is the reason this file (or a copy of it) cannot be reused? What is so special about it?

I'm not sure I fully understand what you mean by "associated". Does PVsyst detect when the information in the SIT and/or MET file is different from the PRJ file? Or do the SIT and MET file contents always get copied to the PRJ whenever the PRJ is opened? Is the PRJ information copy perhaps more of a back-up in case the SIT or MET file get lost? And if the variant is simulated again, will it use the data from the VCi file or from the changed SIT and MET?

A copy of the SIT file contents appears to be stored in the PRJ file and in each VC# file. Is the information in the PRJ file and/or the VC# files updated when the SIT file changes?

This is normal. Months with higher yield influence the annual PR more strongly. If you want to check, just calculate a weighted average values of the monthly PR (weighted by kWh).

Good question/suggestion. Any news?

One way could be to plot the Sandia model over the temperature range of interest and do a regression fit with the PVsyst model. For the purpose of the simualtion, Tcell is the unknown and all the others are given or estimated. The U in the above equation is one of the given or estimated parameters. You could try a few different values to see how the simulation is affected by this uncertainty. I hope it helped!