Experimentally exploring the synergy of rotating twisted tape turbulators and hybrid nanofluids for enhanced photovoltaic thermal system performance

In the present study, it is experimentally investigated how the functionality of a photovoltaic thermal unit is affected by utilizing a rotating turbulator and a hybrid nanofluid at the same time. Twisted tape is used as turbulator and water-TiO2/Co3O4 is considered as nanofluid. Two perspectives of energy and exergy are used to analyze the functionality of the unit. The impacts of mixing ratio of TiO2:Co3O4 nanoparticles (1:0, 0.9:0.1, 0.7:0.3, 0.5:0.5, 0.3:0.7, 0.1:0.9, and 0:1), volume concentration of nanofluid (0 %, 0.1 %, 0.5 %, and 1 %), mass flow rate of nanofluid (20, 40, 60, and 80 kg/h), twist pitch of turbulator (10, 30, and 66 mm), and turbulator rotating speed (0, 100, 200, 300, 400, and 500 rpm) on the system functionality are examined. The highest overall energy efficiency of 73.28 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 500 rpm, and mass flow rate of 80 kg/h. Moreover, the highest overall exergy efficiency of 13.83 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 400 rpm, and mass flow rate of 20 kg/h.