Electrical and thermal performance comparison between PVT-ST and PV-ST systems

Abstract

Both photovoltaic (PV), and photovoltaic thermal (PVT) are technologies that use solar energy for power output. Combining them with solar thermal (ST) can enable the generation of electricity as well as high-temperature hot water. In this study, The heat transfer model was established to investigate the thermal, electrical and overall performance of the two systems, which one is a separately operating PV and ST system (i.e. PV-ST system) and the other is a PVT and ST system in series (i.e. PVT-ST). By comparing the electrical, thermal and overall performance of the two combinations under different solar radiation, ambient temperature and inlet temperature, the application range, advantages and disadvantages of the two combinations are given, which can provide guidance for the design of higher electrical and thermal output system. The comparative study of the two systems shows that the electrical efficiency, thermal efficiency and primary energy saving efficiency of the PV-ST system are higher than that of the PVT-ST system under the conditions of low ambient temperature and solar radiation. This makes the PV-ST system have a wider application prospect in such low temperature and weak radiation environment conditions. However, under the environmental conditions of higher ambient temperature and stronger solar radiation intensity, the electro-thermal efficiency and primary energy saving efficiency of PVT-ST system will be higher than that of PV-ST system. The PVT-ST system will be widely used in high temperature and strong radiation conditions.