Experimental study on a low-concentration thermal/photovoltaic system and its transient behavior in a hot and dry climate

Thermal/photovoltaic (PV/T) modules have attracted significant attention from researchers due to their ability to simultaneously generate thermal and electrical energy. In this study, a periodic evaluation was conducted on a low-concentration PV/T system. The primary objective was to assess the system's performance from both energy and economic perspectives. This innovative system integrates nanoparticle coatings on the absorber and flat concentrators to enhance solar energy absorption efficiency. Furthermore, periodic evaluations were carried out using regression analysis to analyze energy and economic performance. Experiments were conducted under steady flow conditions. Given the high cost of Fresnel lenses and the risk of solar panel degradation due to excessive solar radiation, the importance of protecting equipment against environmental conditions is highlighted. Flat mirrors were employed as concentrators to optimize solar radiation absorption. Additionally, a graphene oxide black nanomaterial coating strategy was applied to enhance thermal efficiency. The system also utilized a harp tube network and liquid distribution behind the PV panel to extract generated heat, thereby reducing the panel surface temperature and facilitating electrical energy production. Experimental results showed that the system could absorb up to 1251.40 W m-2 of solar energy daily. With the nanoparticle coating's high solar absorption capacity, the system achieved a daily thermal efficiency of up to 46.95%. Electrical energy production was maintained at 15.20% efficiency. A daily reduction of 10-15 degrees C in the collector surface temperature increased electrical efficiency by 2-4%. Regression analysis revealed a 92% similarity between predicted and experimental results. The thermal and electrical energy payback periods were approximately 1.23 and 3.21 years, respectively. Additionally, economic analysis indicated that thermal energy profitability was 70.25% higher than that of electrical energy.