Efficiency Improvement of Solar Photovoltaic Thermal Systems by Experimental and Numerical Analysis

The power output of solar panels shows an inverse relation with increasing its operating temperature and that affects largely for countries like Sri Lanka, which are situated near the equator. Possible cooling techniques, which are aligned with the Sri Lankan context, were studied by referring to past research and available systems. Rear side forced water-cooling with a thermal collector which is known as the hybrid system was identified as the most feasible technique by considering economic and environmental factors. The theoretical model was developed to estimate the design parameters of the thermal collector and cooling performance. The number of ten thermal collector design configurations were modeled and analyzed the cooling performance using ANSYS fluent simulations. The best design configuration was identified based on heat transfer and manufacturing capability. A prototype of the selected design was manufactured to investigate the cooling performance experimentally. The experimental setup was developed using two 100 Watts solar panels and a small scale cooling tower. Both power and panel temperature variation were analyzed both numerically and experimentally. The numerical model was validated using experimental results and design parameters were optimized as it gives a better cooling performance. Both numerical and experimental analysis shows that integrating a rear side cooling system would increase both electrical and thermal efficiency by 65%. The electrical efficiency improvement is 2.5 % and electrical power generation is increased by 28% compared to the panel without cooling. Considering the cost benefits and the environmental conditions of Sri Lanka, using a solar PV hybrid system is a feasible option to enhance both electrical and thermal gains.