Experimental study of the effect of simultaneous application of the air- and water-cooled flow on efficiency in a Photovoltaic thermal solar collector with porous plates

This paper examines the effect of simultaneous use of air-and water-cooled flow on the efficiency of a solar photovoltaic thermal (PVT) panel. A copper pipe system is used for water cooling and some fans are used under the PVT for air cooling. Also, some porous plates are used at the bottom of the solar panel. By changing the volumetric flow rate (VFR) of water in the range of 0.5 to 2.5 L/min with 1, 2, or 3 fans under the PVT, the values of electrical efficiency (ELE), thermal efficiency (THE), total efficiency (TOE), the amount of electricity generated by PVT and the heat transfer (HT) takes place in PVT are estimated. This experimental research is conducted in the summer from 10:00 to 16:00. Each test is performed in one day and the output power of PVT and a similar PV, water temperature in the inlet and outlet of PVT and the amount of solar heat flux are recorded. The results show that an increment in the VFR of water enhances the amount of ELE of PVT. Increasing the number of fans reduces the efficiency so that the maximum value of ELE of PVT for water VFR of 2.5 L/min without using the fans, which is equal to 11.99 %. Enhancing the number of fans and VFR increases THE and TOE of PVT. The maximum values of THE and TOE of PVT are 70.59 % and 81.61 %, respectively. In the best case, using a water VFR of 2.5 L/min and three fans, the power generation is enhanced by 22.56 W by the panel. The value of ELE can be improved by 5.62 % by cooling with a VFR of 1.5 L/min in the absence of fans.