The schematic diagram of control circuit for cooling and cleaning system is shown in Fig. 4. By comparing the measured values of temperature at the rear face of PV module (T_rc) and the ambient temperature (T_amb) through a comparator, the output of comparator is high if T_rc≥ T_amb+ 2 and low if〖 T〗_rc≤ T_amb+ 2. This condition control of the temperature of the module being dependent on the rear face temperature of the module and the ambient temperature to keep the module temperature near the ambient temperature.