EXPERIMENTAL INVESTIGATION OF USING GRAPHENE NANOPLATELETS AND HYBRID NANOFLUID AS COOLANT IN PHOTOVOLTAIC THERMAL SYSTEMS

It is a common observation that the photovoltaic (PV) panel shows a compromised performance when its temperature rises. To handle the performance reduction, most PV panels are equipped with a thermal absorber, for removing the solar cells' excessive heal with the help of a heat transfer fluid. The mentioned thermal absorber system is termed as PV thermal or simply PV/T. This study aims to experimentally investigate the effects of agraphene nanoplatelets nanofluid, distilled water, and hybrid nanofluid as transfer fluids in PV/T collectors. A hybrid nanofluid comprises Al2O3 and graphene nanoplatelets. An outdoor experimental setup was installed and tested under the climatic conditions in Karabuk, Turkey, to measure the inlet as well as outlet PV/T fluid temperatures, ambient temperature with solar radiation, and surface temperatures of both PV/T collector and the PV panel. The mass percentage of the coolant fluids was 0.5% (by weight) and their flow rate was 0.5 Lpm. Results show that the graphene nanoplatelets nanofluid is the most effective fluid because it showed superior thermal efficiency among all the tested fluids. Adding a thermal unit to the PV/T unit increased the overall energy efficiency by 48.4%, 52%, and 56.1% using distilled water, hybrid nanofluid, and graphene nanofluid, respectively.