To depict the impact of the irradiance on the efficiency of the PV generator, an efficiency curve of a multicrystalline
PV module was used. The increase of the PV generator temperature above the ambient temperature is
assumed to be 29 °C for an irradiance of 1000 W/m², which is appropriate for rooftop systems with good ventilation.
The thermal inertia of the PV generator was depicted with a PT1 element and a thermal time constant of 10 minutes
[5]. The decrease of the PV power output due to increasing temperatures of the PV generator compared to the
temperature of 25 °C is set to -0.4%/°C. Further PV generator losses of 8% are considered with empirical factors