The Effect of the Impinging Angle of Multi-Rectangular Air Jets on the Performance Improvement of Passive Solar Photovoltaic-thermal Systems

This work represents a major effort to increase the energy yield and efficiency of passive PV/T systems by developing a new efficient cooling technology consisting of multiple impingement air jets. The hot back side of PV/T is equipped with multiple rectangular slots for impinging air jets and a main channel along the absorber for crossflow air. This can create vortices between the flow jets and the main flow at the back side of the PV/T, enhancing heat transfer rate and reducing PV/T surface temperatures. Different inclination angles of the impinging air jets ranging from 45 to 90° were tested and optimized to achieve optimum energy production and overall efficiency. A commercial CFD code based on ANSYS Fluent 2024 was used to simulate the proposed PV/T system with multiple impinging air jets under climatic conditions of state of Ghardaïa, Algeria. Results showed that the optimum inclination angle of the impinging air jets was 90°, which achieved the highest energy production. This is due to the increase associated with the generation of air vortices inside the main channel with the main airflow and to the vertical collision with the back surface of the PV/T module. The average daily surface temperature, electrical, and thermal energy outputs of the proposed PV/T system are 1.071–2.82%, 5.00–18.98%, and 20.37–70.79%, respectively, higher than that of traditional PV/T system. The average electrical, thermal, and total efficiencies of the proposed PV/T plant were 5–18.98%, 15.72–46.62%, and 15.64–46.42%, respectively, higher than those of the traditional PV/T system. The study proved that the new cooling technique with multiple air jets can be used to achieve high heat transfer rates and significantly enhance the electrical and thermal energy output of PV/T system.