Experimental investigation of a hybrid photovoltaic evaporative cooling (PV/EC) system performance under arid conditions

An innovative hybrid photovoltaic evaporative cooling (PV/EC) system has been experimentally investigated in order to improve its efficiency by cooling the PV panel and simultaneously providing cold humid supplied air. PV/EC system integrates a PV panel and a traditional roof-mounted evaporative cooling system. The innovative PV/EC combines a PV panel and the evaporative cooling system beneath the PV panel as one structure. This system eliminates a lot of space that would otherwise be needed by a cooling system driven by PV panels. Also, this new design structure reduces the solar radiation incoming to the building roof in summer. The proposed evaporative system tested a cellulose cooling pad of three thicknesses (50, 100, and 150 mm) with three water flow rates (1, 2, and 3 LPM), while the air velocity ranged between (2-3 m/s). The results, compared to a normal PV panel without cooling, showed an improvement in both the electric and thermal performance of PV/EC systems. The PV panel efficiency improved by 7.4%, 10.5%, and 11.2% for pads #1, #2, and #3 respectively. The average temperature reduction of pad #1 reached (15 degrees C), and was about (20 degrees C) for pads #2 and #3. The supplied air temperature difference was (5.5 degrees C, 9.2 degrees C, and 13.9 degrees C) for three pads respectively. The best supplied air dry-bulb temperature was 24.7 degrees C and 71% relative humidity for pad #3.