Combined cooling of photovoltaic module integrated with thermoelectric generators, by using earthenware water tank and ultrasonic humidifier: An experimental study

The purpose of the present research is to reduce the temperature of photovoltaic (PV) module using a combined cooling method in order to improve electrical output, having better performance and simultaneous integration of thermoelectric generators (TEG) with it and to generate surplus electricity from the existing temperature difference in the proposed system. An L-shaped earthenware water tank as the passive cooling method and an ultrasonic humidifier inside the tank as the active cooling method formed the combined cooling sections of the proposed system. The ultrasonic humidifier converts the cooled water inside the earthenware tank to cold mist in the enclosed space backside of the PV module by a piezoelectric actuator based on the cavitation phenomenon (reduction of PV module temperature occurs by heat transfer and conductivity). Temperature difference between the surface of the PV module and cold mist on backside of the PV module converts to surplus electricity by TEG. In this study, three cold mist creation capacities of 250, 400 and 550 mL/h were investigated and the greatest improvement in the utilization of solar energy compared to the control PV module was for the cold mist creation capacity of 550 mL/h. Temperature reduction of PV section of about 5.2 °C, PV maximum power improvement of 5.1% and total efficiency improvement of 4.96% were obtained in the proposed system with cold mist creation capacity of 550 mL/h compared to control PV module. It was concluded that unlike cooled PV module, the share of TEG array is very negligible in the total efficiency improvement.