PR corrected calculation (no PVSYST software related)

[vincenzo_diana]

Hi everybody,

I need to calculate the PR corrected for a PV plant ground installed and connected to the grid.

I have just T back (temperature measured at the back of the module) as input data.

My question is: do I need any other data to calculate the corrected PR? wind or Tamb?

Using the formula of NREL in order to obtain the PR corrected, if I consider the day as time frame, G at plan of array is given by the monitoring system,

Tcell typ-Tcell,i should be the difference between 25° and the daily average Tback.

The daily average Tback is a simple average or is it weighted on the irradiation?

Thank you very much

[André Mermoud]

For the calculation of the weather corrected PR, you need indeed the array temperature, but in hourly values.

The expression proposed by the NREL supposes an accumulation/calculation with hourly values.

NB: This calculation is done in PVsyst. You can get it under the variable named "Weather corrected PR", i.e. PRTemp.

You can show it on the report, by using in the Report's dialog menu: "Settings > General Options > Monthly values table". Here you can choose "Weather corrected PR".