Experimental study of the effect of sheet-and-sinusoidal tube collector on the energetic and exergetic performance of a photovoltaic-thermal unit filled with biologically synthesized water/glycerol-silver nanofluid

The focus of this experimental work is on assessing the energetic and exergetic performance of a photovoltaicthermal unit equipped with a sheet-and-sinusoidal tube collector (PVTW). The performance metrics of the unit are compared with those of the PV panel without cooling and a photovoltaic-thermal unit equipped with a sheet-and-plain tube collector (PVTP). The considered heat transfer fluid is the biologically prepared water/glycerol-silver nanofluid. The experiments are carried out for different mass flow rates of nanofluid (20, 40, 60 and 80 kg/h) and volume concentrations of silver nanoadditives (0, 0.50 and 1%). Both the PVTW and PVTP units showed better energetic and exergetic performances at higher mass flow rates (m. nf) and nanoadditive concentrations (f). Moreover, for all the examined cases, it was found that the performance metrics of the PVTW unit is superior to those of the PVTP unit. The overall energy and exergy efficiencies of the PVTW unit were respectively in the range of 67.86-80.57% and 13.8-14.49%, while these intervals for the PVTP unit were 61.34-70.85% and 13.63-14.16%. Therefore, it was found that the overall energy and exergy efficiencies of the PVTW unit is 9.11-15.51% and 1.12-2.59% higher than those of the PVTP unit.