Cell Temp versus Ambient temperature in string voltage sizing

[IB31]

I am looking for clarification for the string voltage sizing calculations in PVsyst. The Maximum and Minimum temperature in the project setting window is ambient temeprature value or Module/cell temperature . If it is cell /Module temperature (as per help) then does user need to find the cell/ module temperature using ambient temperature using the IEC 68153 which is bit tricky because it is dependent on Irradiance and coefficients.

PVsyst does calculate the module temperature hourly but can user input the min and max cell temp values in the project setting window without much of calculations.

[IB31]

On 10/10/2023 at 5:28 PM, IB31 said:

I am looking for clarification for the string voltage sizing calculations in PVsyst. The Maximum and Minimum temperature in the project setting window is ambient temeprature value or Module/cell temperature . If it is cell /Module temperature (as per help) then does user need to find the cell/ module temperature using ambient temperature using the IEC 68153 which is bit tricky because it is dependent on Irradiance and coefficients.

PVsyst does calculate the module temperature hourly but can user input the min and max cell temp values in the project setting window without much of calculations.

@Michele Oliosi Looking forward for any response here. Thank you

[Michele Oliosi]

Regarding the “Lower temperature for absolute voltage limit”, since this is a safety condition, we make the hypothesis that the cell temperature is the ambient temperature (which corresponds to the highest possible voltage). It is customary to put the lowest possible ambient temperature over several years.

The other temperatures are usually not very constraining, so it is okay to put a rough estimate there.