Investigation of the thermal performance enhancement of a photovoltaic thermal (PV/T) collector with periodically grooved channels

Abstract

To avoid overheating, thermal failure and even fire in photovoltaic modules (PVMs), the excellent thermal performance of photovoltaic thermal (PV/T) collectors is required. To improve the cooling capacity and required pump power of parallel cooling channels (PCCs), the heat transfer in parallel cooling channels with periodically expanded grooves (PEGs) is studied in this paper. The presence of PEGs leads to vortexes in the grooves and more pressure loss of the PCCs. The heat transfer of the PCCs is enhanced by the redevelopment of thermal boundary layers and the vortexes in the grooves enhance. The mean temperature of the PVMs with PEGs is about 4 K lower than that with smooth channel. The pressure drop is the highest with a rectangular column groove compared with those of semicylinder and triangular column-shaped grooves. Increasing the groove length enhances the convective heat transfer but leads to a larger flow resistance of the PCCs. Although decreasing the groove space leads to enhanced heat transfer, the figure of merit of the PCCs is nearly the same for different groove spaces.