A CFD study of the energy and exergy performance of photovoltaic thermal systems with a porous collector and a PCM-copper foam passive component with different geometries

Passive methods play a great role in enhancing heat transfer and overall efficiencies in photovoltaic thermal (PVT) systems. The integration of phase change materials (PCMs) is explored as a strategy to improve system performance during periods of low solar radiation. However, the inherent limitation of PCMs’ low thermal conductivity in transferring heat from the photovoltaic (PV) unit to the PCM bulk is acknowledged. In response, this study proposes the integration of a PCM-copper foam composite into a PVT system, coupled with the placement of a porous insert in the collector tube to maximize thermal energy harvesting. The main novelty of this research is to improve the geometry of the conventional PVT systems. The research extensively discusses the influence of the geometry of PCM-copper foam containers on the performance of PVT systems. As shown in the results, the geometry of the porous PCM container could significantly affect the latent heat absorption and extraction in the charge-discharge process. Notably, for a water flow rate of 30 kg/h, a porous PCM tank with a semi-circle cross-section proves optimal, providing higher electrical and thermal efficiencies. This configuration yields elevated electrical and thermal exergies throughout the seasons, accompanied by a significant up to 1°C reduction in the temperature. Additionally, for a water flow rate of 10 kg/h, a triangular configuration is identified as offering superior thermal efficiency.