Thermal Parameter Calculation using Meteo Data (Ambient Temperature)

[Hossam]

The meteonorm 8.1 database has hourly values of ambient temperature. 
Does PVsyst calculate the Cell temperature using the ambient temperature value at the specific time during the simulation or it uses the monthly average for all days?
I mean does it calculate the cell temperature only during daylight or it merges all heat transfer throughout the year, day and night.

[Michele Oliosi]

Dear Hossam, the cell temperature is calculated with the ambient temperature at each specific hour.

[Hossam]

Does it include the ambient temperatures at night in the simulation of thermal losses?

[Michele Oliosi]

By thermal losses we only account the losses due to the loss of efficiency when the module heats up during the day.
Unless you are concerned with infinitesimal variations of temperature, since the thermal inertia of modules is about 10 minutes, you don't need to merge the heat transfer throughout the year, day and night to simulate in hourly steps. Considering the heat transfer within the hour is enough.

[Hossam]

This means the losses are only calculated using the hourly temperature values only in the presence of irradiance or throught the day (24 hours)?