Experimental evaluation of photovoltaic thermal (PVT) system using a modular heat collector with flat back shape fins, pipe, nanofluids and phase change material

In recent years, the study of decreasing photovoltaic (PV) units cell temperature increase caused by solar excess energy, which is converted into heat rather than electrical energy, resulting in voltage output reduction and thereby lowering overall efficiency, has been the trending subject of much researches. In this study, a novel heat collector, which is an assembly of a series of flat heat sinks and serpentine copper tubes in an enclosed sealed container filled with paraffin wax is proposed. This assembly as an individual set is clamped and attached by screws to the rear side of the photovoltaic panel. The proposed system was experimentally investigated outdoors by utilizing SiC/water and Graphene/water nanofluids and water as cooling mediums with volume fractions 0.2 % and 0.4 % at 0.5LPM and 1LPM flow rates and this system was compared with a photovoltaic panel with no cooling. The achieved results showed that both nanofluids caused temperature drop compared to using water as coolant and the system with no cooling. Also, experimental results showed that the Graphene nanofluid caused more temperature reduction and accordingly resulted in higher power and efficiencies. Moreover, increasing volume concentration and flow rate of the working fluid led to have better performance in all the tests. Also, increasing volume concentration of nanofluid and flow rate caused to have more temperature reduction and as a result, more enhancement in electrical and thermal efficiencies.