An experimental study on optimization of coolant mass flow rate in a photovoltaic/thermal system

Abstract

Steady, continuous, and homogeneous cooling of photovoltaic panels that consume less energy for circulation of coolant is extremely important for preventing higher energy loses especially in hotter conditions. In this study, a novel steady continuous active cooling application with water, as the coolant, was applied in a compact photovoltaic/thermal hybrid system in order to find out the effects of coolant mass flow rate and to optimize the required amount of cooling for maximizing electrical efficiency by measuring the real load voltage and current values formed on the resistive load designed for the selected photovoltaic module. It is found that the reduction in panel temperature for the cooled panel can be accepted to be enough, especially for 31.38 kg/h coolant mass flow rate, since the operating temperatures of the cooled panel reached quite near to the ambient temperature. The means of the temperature reduction for cooled panels were between 13.06°C and 13.74°C as compared with the referent panel. The increase rate of average power for the cooled operations were in between 6-8%, while the instantaneous power increase, especially in midday periods, were reached to its highest values between 13% and 15% in comparison to the referent panel. The highest percent increase in power output was derived as 7.62% for the ṁ = 31.38 kg/h coolant mass flow rate at 12:30 pm. The highest daily cumulative electrical energy production was observed for the coolant mass flow rate of 39.66 kg/h, with 6.3% of increase.