Numerical analysis and RSM modeling of the effect of using a V-cut twisted tape turbulator in the absorber tube of a photovoltaic/thermal system on the energy and exergy performances of the system

The application of V-cut twisted tape turbulator inserted in the absorber tube of a photovoltaic thermal (PVT) system was investigated through a 3-D numerical analysis. The objective was to determine the effect of turbulator pitch distance (50 mm, 77 mm, and 100 mm) and Re number (500, 1000, 1500, and 2000) on the PVT energy and exergy performances. The results were compared with those obtained for the absorber tube without turbulator. Our findings demonstrated that the pressure drop and PV temperature, respectively, escalates and diminishes by 78–84% and 5.69–6.68% for the case with turbulator (pitch of 100 mm) as Re increases from 500 to 2000. In consequence, the overall energy efficiency and overall exergy efficiency improve by 15.76–14.27% and 12.01–8.68%, respectively, for the increase in Re within the studied range. In addition, the application of turbulator with a pitch of 100 mm improves the overall energy and exergy efficiencies of the PVT system by 3.04–7.70% and 4.03–13.08% at the Re range of 500–2000 as compared to the without turbulator case. Moreover, the greatest useful thermal and electrical efficiencies were obtained for the PVT with turbulator pitch of 100 mm and at Re=2000, which yields the highest overall thermal and exergy efficiencies of 75.46% and 16.34%, respectively. Furthermore, RSM technique is utilized to obtain a model for the overall energy and exergy efficiencies versus Re and P.