An improved multi-layer thermal model for photovoltaic modules

An essential task in devising photovoltaic power plant energy production capacities is based on the evaluation of a PV module thermal behavior from typical meteorological conditions in a given place. Multi-layer models (MLMs) allow to evaluate precisely the PV cell temperatures and to calculate both front and back layer temperatures through at least a 3 temperatures multi-layer models (3T-MLMs). Front and back layer temperatures, especially the back layer temperature, can be measured during the operation of a PV module, so it is likely to tune on-line the thermal model and calculate very precisely the inner temperature. MLMs are based on thermal energy balance equations between the PV module and the surrounding environments. This study introduces an innovative MLM, that allows to evaluate precisely and quickly the front and back cover variations of superficial temperatures with a 1second time step. The predicted thermal behavior of the PV modules is described and checked against measured data. The numerical results put also in evidence the uncertainties introduced by the environmental variables (ambient temperature, irradiance, wind speed) measurements.