Performance analysis of photovoltaic thermal collector with phase change material and copper foam absorber

Abstract

PVT (Photovoltaic Thermal) collectors produce both thermal and electrical energy. Optimizing heat dissipation from the photovoltaic (PV) surface to a designated cooling medium, utilized for thermal energy storage, is imperative in achieving enhanced efficiency within PVT systems. Phase Change Materials (PCM) are promising thermal energy storage because of their significant latent heat during charging and discharging. PCM's low thermal conductivity continues to be a significant disadvantage in preventing efficient dissipation of heat from PV panels. The use of porous metal foams can provide a solution given their excellent thermal conductivity, low density, and lightweight. The incorporation of both materials would result in lower PV temperatures and greater overall efficiency because of the effective dissipation of the heat produced by the PV module. This study aimed to evaluate the performance of a PVT system using PCM with Copper Foam Matrix (CFM) with submerged serpentine copper tubes for fluid flow. Computational fluid dynamics simulations were performed to visualize the system and compare it with conventional designs. A mathematical model based on energy balance was also developed. To fabricate the collector, serpentine tubes were affixed to the rear of the panel using a thermally conductive silicon adhesive. The copper foam was then cut to the exact dimensions of the pipes to provide a direct connection to the panel's back. The PCM was melted and poured into the rear of the panel. Experimental studies using an indoor solar simulator were conducted to test the PVT collector with water as working fluid. The experimental results demonstrate that the PVT collector with PCM and CFM outperforms conventional PVT collectors and achieves maximum thermal and electrical efficiencies. The PVT collector demonstrated thermal and electrical efficiencies of 72% and 10.7%, respectively, under a solar irradiance of 1000 W/m2, an ambient temperature of 20˚C, and a flow rate of 0.04 kg/s. The average photovoltaic temperature recorded under the aforementioned conditions was 49℃. The exergy efficiency of a photovoltaic-thermal (PVT) system that utilizes a porous medium filled with phase change material (PCM) is 14.4%, which is greater than the exergy efficiency of a PVT system that incorporates PCM alone, recording a lower efficiency of 13.4%. The inclusion of the Phase Change Materials (PCMs) and Porous Copper Foam Matrix (CFM) resulted in the enhancement of the thermal and electrical efficiencies of the system. Experimental and numerical results were compared and was in close agreement to validate the efficiency and performance of the PVT. Therefore, this research was a valuable contribution to the PVT industry by providing an innovative solution for significant improvement in the overall efficiency and performance of the PVT collector.