Thermal Efficiency Enhancement of Solar Air Collector Integrated with an Electric Heater Using Experimental and Numerical Approaches

Although numerous studies have investigated individual methods to improve the performance of solar air heaters (SAHs), such as flow obstruction barriers, porous media, nanofluids, and thermal energy storage units, the overall integration of these reinforcement strategies into a unified, sustainable system remains to be defined. The current study presents a hybrid solar air heating configuration that combines a solar air collector (SAC) with an electric air heater (EAH) powered by photovoltaic (PV) panels, aiming to stabilize outlet air temperature and enhance overall thermal efficiency. Experimental and numerical approaches were employed to evaluate the influence of barrier geometry (flat, trapezoidal, and V-groove) and airflow rate (53, 158, and 317 L/min) on system performance using three SAC models. Experimental results revealed that lower airflow rate promotes greater temperature rise (ΔT) due to longer air–surface contact, while V-groove barriers achieved the highest ΔT and collector efficiency among all configurations. At higher airflow rates, the absorbed energy factor F c ( τ α ) increased to approximately 0.73, whereas the heat loss factor F c U decreased, indicating reduced thermal losses and improved energy transfer. Model III demonstrated the most effective heat absorption, confirming its superior thermal design. The integrated SAC–EAH system exhibited improved overall efficiency, with the SAC functioning effectively as a preheating unit and the EAH sustaining thermal stability during variable solar conditions. Numerical results showed that the highest temperature difference occurs at the V-groove barriers at an air flow rate of 53 L/min. In contrast, the difference between inlet and outlet temperatures decreases across the remaining models, with reduced percentages of 11.8% and 12.7% for Model II and Model I, respectively. Numerical simulations ensured the experimental outcomes, showing close agreement with the temperature variation trends and validating the system’s enhanced thermal performance.