Cooling of photovoltaic (PV) panels was investigated experimentally outdoors using two nanofluids and water as a cooling medium for volume flow rate ranging from 500 to 5000 mL/min at concentrations (0.01 wt.%, 0.05 wt. %, and 0.1 wt.%) under different radiation intensity. Two types of nanofluids were used, namely Al2O3 in water- polyethylene glycol mixture at pH 5.7, and TiO2 in water- cetyltrimethylammonium bromide mixture at pH 9.7, respectively. The cooling of PV panel required incorporating a heat exchanger of aluminium rectangular cross section at its back surface to accommodate different volume flow rate of the cooling medium aforementioned. The system was tested under climate conditions of Jerash-Jordan, Determination of flow characteristics; friction factor,/and product of friction factor Reynolds number, of TiO2, Al2O3 nanofluids and water as a cooling medium were investigated. Also, a fRe comparison of the temperature between the cooled PV cell and without cooling for volume flow rate ranging from 500 to 5000 mL/min was presented. Results showed that the nanofluid cooled PV cell in both types caused higher decrease in the average PV cell temperature compared with the cooled cell with water and without cooling. In addition, Al2O3 nanofluid showed better performance than TiO2 nanofluid. Furthermore, experimental results showed that higher concentration of nanofluid produces a better cooling effect of the PV cell for all the studied range of volume flow rate. Also, electrical analysis of power and efficiency showed that TiO2 nanofluid gives better perfomance for the studied range of volume flow rate and concentrations compared with water cooling and without cooling.