Comparative study of multiple low-concentrating PV/T systems using the multiphysics method for process heat applications

A multiphysics performance assessment was conducted to identify the optimal concentrator and coolant that delivers superior performance. The investigation was conducted on a 2.5X concentrator truncated to a 2.0X compound parabolic concentrator (CPC, parabolic-type), extended compound parabolic concentrator (ECPC, combined parabolic and flat-type), and V-trough concentrator (VTC, flat-type) photovoltaic thermal (PV/T) systems using water, Al 2 O 3 /water, and ZnO/water nanofluids, Cu-Al 2 O 3 /water, and Ag-ZnO/water hybrid nanofluids throughout the day. The maximum difference in optical efficiency between VTC and CPC was 5.36%, whereas the difference between VTC and ECPC was 12.80%. The outlet temperatures obtained in VTC-PV/T, CPC-PV/T, and ECPC-PV/T were 69.15 °C, 68.92 °C, and 68.67 °C at noon, respectively. Apart from noon, VTC-PV/T outperformed CPC-PV/T and ECPC-PV/T. The VTC-PV/T provides 3.41% higher thermal efficiency than CPC-PV/T and 9.16% higher than ECPC-PV/T. The peak difference in electrical power between VTC-PV/T and CPC-PV/T was 5.38%, and between VTC-PV/T and ECPC-PV/T was 17.39%. The VTC-PV/T system outperformed the CPC-PV/T and ECPC-PV/T systems across all multiphysics metrics (optical, thermal, and electrical). In VTC-PV/T, Ag-ZnO/water, ZnO/water, and water achieved maximum outlet temperatures of 74.09 °C, 71.16 °C, and 69.15 °C, respectively. The water, ZnO/water, and Ag-ZnO/water achieved maximum thermal efficiency of 57.99%, 53.47%, and 45.99%, respectively. The Ag-ZnO/water hybrid nanofluids demonstrated the highest outlet temperature, whereas water yielded the highest thermal efficiency. All three LC-PV/T systems produce similar output at noon because the rays were not intercepted by the reflector. The VTC-PV/T system with Ag-ZnO/water can be used for low to medium temperature process heat applications.