Modeling a Combined Photovoltaic-Thermal Solar Panel

Ab stract: The electrical efficiency of a photovoltaic (PV) cell decreases as its temperature increases. Since PV cells must be arranged in direct sunlight to produce electricity, heating is inevitable. A heat exchanger can be adapted to a PV cell to extract heat and hence increase the conversion efficiency while using heat absorbed from the cells for secondary applications. The thermal system consists of a rectangular aluminum reservoir that is mounted to the backside of PV panels, through which water flows. Analysis of the proposed photovoltaic-thermal (PV/T) solar panel design was performed using COMSOL Multiphysics software. Combinations of water flow rates and reservoir thicknesses were analyzed to determine which produced optimal PV/T total efficiencies. Higher total panel efficiencies (additive efficiency of thermal and electrical efficiencies) were achieved in configurations utilizing the highest flow rates and largest reservoir thickness. However, elevated flow rates translated to minimal net temperature differences between the PV/T panel inlet and outlet.