TMY vs Synthetic meteo files

[ASBRIC]

Hello, everyone:

I would like to ask something about the meteo files. I'm studying some locations using NREL / NSRDB TMY, importing the information directly from PVsyst. After creating the .sit files the software also creates an "...NREL_TMY.MET" file. But after that I can also create a synthetic meteo file for that site.

My question is whether it's convenient or not to create that syntehtic file, because it always results in a higher yield than the TMY file. I wonder if that's the right procedure or if I get fake results by doing it.

Thanks in advance!

[Emanuel Rodriguez]

Hi ASBRIC,

I think you are doing it right. When you create a .SIT file you are just setting the place downloading just monthly meteo data, see image 1. So you get GHI, DHI, Tamb, Wind velocity and RHumidity.

So PVsyst generates a synthetic meteo file hour by hour in order to calculate the simulation. See image below

I do not know how can Pvsyst simulate the system (mainly losses) if no hourly calculations are performed. How did you get results without creating a .SIT file? 

As far as I know, the TMY is supposed to provide the "same data" (different format) as the .MET file. So the creation of a .MET form a TMY is just fomat conversion.

To sum up, if you have a TMY file you should import it,  create the .SIT and the .MET files after that you should run the simulation selecting the meteo data from .MET. 

BR,

 

Emanuel

 

 

 

 

[Arati]

But when we select metro file from geographic sites it does not show . Met file. Only sit is shown. How can we select . Met for simulations