Modeling of a PV system by a back-mounted spray cooling section for performance improvement

•A PV system by a back-mounted spray cooling section for performance improvement is proposed.•The effects of geometric dimensions, nozzle arrangements and ambient conditions on the PV performance are simulated.•The optimal configuration of the proposed PV cooling system is obtained.•The proposed system reduces the average cell temperature by 16.90 °C and obtains an increment in the conversion efficiency of 1.52%. The cell temperature is an important factor affecting the operation performance of a photovoltaic (PV) module. In this work, efforts are made to study the possibility of a PV system with spray cooling section formed by different lengths of guide and support plates at the rear surface of the PV module. A 3-D model of heat and mass transfer that integrates photoelectric conversion efficiency varying with the cell temperature under different spray cases was established. The effects of different parameters like nozzle height, the lengths of guide plate and support plate, nozzle installation angle, spray water pressure and ambient conditions on the PV performance were simulated in both spray and non-spray cases. Results show that the optimal configuration of the proposed PV cooling system is obtained at the nozzle height of the bottom scheme where the length of guide plate is 588.9 mm, the length of support plate is 680 mm and the nozzle installation angle is horizontal. Moreover, the average cell temperature and average conversion efficiency at the spray water pressure of 3 bar are 51.90 °C and 17.58%, respectively in the spray case while they are 68.80 °C and 16.06%, respectively in the non-spray case (the solar radiation is kept at 800 W/m2 and the ambient temperature is 35 °C). The PV cooling system leads to an average reduction in the cell temperature of 12.31 °C and an average increment in the conversion efficiency of 1.10% when compared with the non-spray case within the ambient temperature of 31–41 °C at the relative humidity of 45%. There is a slight rise in the average cell temperature as the relative humidity increases in the spray case while the average cell temperature changes a little in the non-spray case within the relative humidity of 15–90% at the ambient temperature of 35 °C. This study proves that the proposed PV cooling system is an effective way to improve the performance of PV module during hot periods.