Abstract Egypt has high levels of solar radiation throughout the year, making solar air heaters (SAHs) a practical and economical way to support sustainable energy applications and reduce reliance on traditional energy sources. This study experimentally investigates the energy, exergy, environmental, and economic (4E) performance of three SAH configurations under different air mass flow rates. The experiment was conducted at the Faculty of Agriculture, Ain Shams University, Egypt (30°11′ N, 31°24′ E). The tested configurations include an airflow channel above the absorber plate (SAH1), an airflow channel below the absorber plate (SAH2), and a modified design with airflow below the absorber plate integrated with perforated V-shaped fins (SAH3). The experiments were conducted during July 2025, and real-time monitoring of temperatures, solar radiation, and airflow was carried out. At a mass flow rate of 0. 009 kg/s, SAH3 achieved the highest average thermal efficiency of 62%, compared with 53% for SAH2 and 44% for SAH1. Regarding exergy efficiency at 0. 006 kg/s, SAH3 achieved an average of 3. 7%, exceeding those of SAH2 (2. 6%) and SAH1 (1. 8%). At 0. 009 kg/s, the SAH3 achieved the lowest energy cost of 0. 0003 /kWh and mitigated CO 2 emissions by approximately 1. 07 tons annually, resulting in an estimated carbon credit of 53. 43 USD. These results confirm that the proposed design is a promising option for sustainable solar thermal applications.
Shaaban et al. (Mon,) studied this question.