Optimizing double-pass solar air collector efficiency: Impact of a perforated discrete V-angled fins

The current study evaluates the impact of newly designed perforated discrete V- angled fins on the thermal efficiency of double pass solar air collectors (DPSACs). While previous studies have examined various fin shapes for heat transfer enhancement, no research has focused on discrete V- angled fins specifically within DPSACs. Addressing this gap, the objective of this study is to assess the effectiveness of three unique configurations of the V- angled fin design: Type I (aligned parallel to airflow), Type II (angled at 45˚ to airflow), and Type III (perpendicular to airflow). Experiments compared a finned collector against a standard smooth model at airflow rates of 0.00932 kg/s, 0.01143 kg/s, and 0.01311 kg/s to determine the influence of fin presence and orientation on DPSAC performance. The results demonstrated the finned collector consistently outperformed the smooth collector, achieving relative daily efficiency improvements ranging from 4.1 % to 9.1 %. Specifically, Type I improved between 4.1 % and 5.1 %, Type II showed gains between 5.9 % and 9.1 %, and Type III achieved relative improvements between 4.3 % and 6.1 %. These findings highlight the critical role of fin orientation, with Type II demonstrating the greatest potential for optimizing heat transfer and overall efficiency. This study provides foundational insights for DPSAC design, confirming that perforated discrete V-angled fins significantly enhance collector performance and offering new directions for solar thermal collector innovation.