Improvement in efficiency of solar photovoltaic power system through heat extraction

Abstract

Solar photovoltaic cell’s efficiency is negatively affected with increase in its temperature. It is necessary to take measure to increase PV cell efficiency and decrease accelerated wear by controlling the operating temperature of PV cell. While PV panels absorb solar radiation and generate electricity its inherent temperature increases and to control this increased inherent temperature, a coolant system of circulating water has been developed. This cooling unit is mounted to back surface of the commercial panel and consists of rectangular reservoir. Modified panel has been tested for several water flow rates and optimized for minimum operating temperature of panel and thus results higher PV panel efficiency. Electrical and thermal performance of modified panel has also been analyzed in comparison with reference one and modeled in MATLAB. It was found that the water flow rate of 0.01 kg/sec could maintain nominal module operating temperature 30.6 ˚C at 800 W/m2, 20 ˚C ambient temperatures and 1 m/s wind speed at installed condition while the nominal module operating temperature of standard module was 50 ˚C under similar operating conditions. It was found that at subjected temperature, PV module electrical conversion efficiency is 5.3% higher than a standard PV module conversion efficiency at an average radiation of 637 W/m2 with passive cooling system and overall efficiency was more than one order magnitude of conversion PV module efficiency. Further, reservoir construction material and its wall thickness have been analyzed on the basis of performance optimization and developed system has been scaled up to 1MW and cost benefit has been analyzed on annually basis and found economically feasible.