The temperature of Photovoltaic (PV) module rises by absorbed incident solar radiation and causes subsequent drop off in electrical efficiency. To overcome this ill effect, an appropriate material must be used to absorb the heat and maintain the temperature of PV module. The purpose of present study is to review and understand various cooling techniques used to enhance cooling and electrical performance. The emphasis was placed on design and operating parameters like absorber configuration, flow pattern, flow rates, climatic conditions, radiation intensity, wind speed, thermal conductivity, glazing, concentration on the electrical and thermal characteristics. The reviewed papers include theoretical analysis, computer simulation, solar simulator and on-field experiments. The study states that the proper selection and utilization of cooling technology, design and process parameters are the key elements in the solar photovoltaic (PV) system to achieve optimum performance.

In this paper, a novel thermal absorber based photovoltaic thermal system is presented. The thermal absorber is attached at the rear surface of photovoltaic, and water is re-circulated to extract heat. The outdoor experimentations are performed at Pune, India (18.7611?N, 73.5572?) on clear sky day, and water temperatures, surface temperature, radiation and flow rate are measured to analyze techno-economical performance at different operating conditions. The surface temperature of the photovoltaic module plummeted from 54.65?C to 47.9?C with the incorporation of a thermal absorber with flipside water cooling at a ranging flow rate of 0.03 to 0.06 kg/sec. The result shows an average enhancement of 4.2 % in the electrical power output of the photovoltaic thermal system. The maximum thermal and electrical efficiencies were 47.82 % and 9.88 %, respectively, at 0.06 kg/sec. The exergy efficiency was found in the range of 9.85-14.30%. Based on the experimental evaluation, uncertainty analysis was performed. The results revealed that the annual CO2 mitigation for photovoltaic and photovoltaic thermal system was 225.46 kg/annum and 464.8 kg/annum, while simple payback periods were 4.53 years 3.03 years, respectively. The analysis offers an efficient estimate of experimental features of photovoltaic and photovoltaic thermal systems from an energy-exergy, environmental and cost-benefit standpoint.