Exergetic advancement of photovoltaic/thermal systems (PV/T): A review

Photovoltaic/thermal (PV/T) systems are emerging as an important branch of solar technology, which combines photovoltaic panels and solar collectors in a single unit to generate electricity and heat from uninterruptible solar energy. Energy systems are typically examined from two aspects of energy and exergy. The exergy of these systems is of great importance because it focuses on the quality of the energy. Due to the unequal quality of electrical and thermal energy, it is clear that the exergetic performance of these systems gives a clearer view of their efficiency compared to their energetic one. The purpose of this paper is to provide a comprehensive review of the researches conducted in the field of the exergy for various types of PV/T systems in the last decade. According to our study, the largest attention was directed at investigating the exergy of water-based, air-based and nanofluid-based PV/T systems, and the exergy examination of other types, especially thermoelectric-based PV/T systems, was rarely performed. Also, a comparison between different PV/T systems shows that using nanofluids, concentrators and optical filters could improve the exergy efficiency of PV/T systems.