daniel.luzzi

Greetings, By analyzing the documentation provided in Performance Ratio PR - PVsyst documentation, it says that the Weather-corrected Performance Ratio uses the following equation: PR (corr) = E_Grid / ( PNomPV * Σ hours ( GlobInc / GRef * (1 - muPmpp * (Tarray - TArrayWeighted)) Where the TArrayWeighted is described as "Array temperature average on the whole year, weighted by the GlobInc value. This is named TArrWtd in the program." When analyzing the monthly PRTemp in the simulation report, I need to be sure that for the monthly result it is used the weighted average annual temperature and not the monthly temperature.

Greetings, When I read the information provided in Project design > Results > Performance Ratio PR, it is clear that the PR is calculated considering the STC values (25°C, 1000 W/m²) of the system, as cited below: "The Performance Ratio is the ratio of the energy effectively produced (used), with respect to the energy which would be produced if the system was continuously working at its nominal STC efficiency. The PR is defined in the norm IEC EN 61724." So, if I'm calculating the PR from a solar plant and comparing with the simulation, during a year long basis, should I consider the Module Reference Temperature equals to 25°C? For me it is not clear if PVsyst uses the monthly average array temperature for calculating the PR as the reference or the 25ºC. One of the main reasons to question it is because of the following text: "Mathematically, if the TArrayAver is calculated with the same data, the yearly PR(corr) value should be equal to the yearly PR. " In my opinion, I can't understand how is it possible if we are comparing different TArray.