The effect of the properties of porous fillers on the performance of a PCM-based photovoltaic thermal system: A CFD study

In thermal systems, combination of PCMs with porous fillers with high thermal conductivity is a proper method to improve their performance. In photovoltaic thermal (PVT) systems, as porous fillers are introduced to the collector tube and PCM bulk, the thermal efficiency increases. Moreover, since the temperature of the PV unit has dropped, the electrical efficiency has improved too. However, the properties of the porous insertion, i.e., permeability and porosity, might affect the pumping work, and consequently, electrical efficiency. In the present study, the effect of metal foam insertions on thermal and electrical performances is analyzed using a computational fluid dynamics (CFD) method. The results show that installing metal foams with porosities of 0.70–0.94 inside the collector and PCM container of a PVT system improves the thermal efficiency without any considerable decrement in electrical efficiency. When copper foam with a porosity of 0.705 is installed within the collector and PCM tank, the highest thermal efficiency of 66.70% is achieved; while, when copper foam with a porosity of 0.94 is used, the maximum electrical efficiency of 13.24% is resulted.