摘要： One of the main problems that limit the extensive use of photovoltaic (PV) systems is the increase in the temperature of PV panels. Overheating of a PV module decreases the performance of the output power by 0.4% to 0.5% per 1°C over its rated temperature that in most cases is 25°C. An effective way of improving electrical performance (power output and efficiency) and reducing the rate of thermal degradation of a PV module is to reduce the operating temperature of the PV surface by a cooling medium. To achieve this, nanofluids can be considered as a potentially effective solution for cooling. In this study, two types of nanofluids, namely Al2O3 and TiO2 water‐based mixture of different volume flow rates and concentrations (0.01%, 0.05%, and 0.1%) by weight, were used. Also, three PV panels were cooled simultaneously using nanofluids, water, and natural air, respectively. Results showed that nanofluids for cooling enhanced heat transfer rate much better than water and natural air. Best results were achieved for TiO2 nanofluids at the considered concentration (0.1 wt%). Nanofluid cooling of turbulent flows for such an application has not been investigated before. These results represent the first application of nanofluid cooling in the turbulent flow regimes and in outdoor conditions including real solar irradiation.