A theoretical study on the performance of some PV-thermal system configuration

The paper deals with hybrid Photovoltaic/Thermal (PV/Th) solar collectors with forced air circulation. Eighteen system configurations, each one combining different PV modules “densities” with different air velocities and different thickness of the air gap, are presented and analysed. Electric and thermal performances of the collector are evaluated by means of a simulation model allowing to predict the effective efficiency of the PV cells (as a function of the temperature) together with the amount of heat removed by the air and the temperature of outlet air. An assessment of the overall energy performances has been undertaken, in terms of saved primary energy, by means of a comparison among the hybrid system and the alternative conventional technologies. The analysis of time series of delivered electric and thermal energies, together with the outlet air temperature values, referred to twelve average monthly design days of Rome location, allowed to assess the effectiveness of the system, related to some possible utilisation of the heat, and to select the best configurations according to different demand requirements.