Parametric analysis for optimizing performance of solar air heating systems with innovative rib configurations

Solar air heating systems remain expensive, prompting a parametric analysis to enhance their efficiency. This study explores an innovative solar air heating system configuration incorporating fins with and without perforations. The fin spacing (b) was varied at intervals of 0.5, 0.3, 0.25, 0.2, 0.15, and 0.1 m for Model (1), adjusting the number of plain fins on the absorber. Subsequently, five models of perforated fins were compared for optimal spacing (b). Calculations focused on parameters such as Nu, friction factor, Colburn factor (j), Poiseuille number, thermal performance factor, and axial velocity. The results reveal that the fin distribution (Model (1)) with a spacing of 0.1 m (Case F) is the most efficient configuration for heat transfer. For Re = 4000, Case (F) shows a Nu/Nus ratio of 5.82 and an f/fs ratio of approximately 4.18. In terms of thermal performance, Model (1) for Case (F) achieves a thermal performance factor of about eta = 3.841. The analysis of thermo-hydraulic parameters underscores the complexity of relationships between these parameters and the absorber configuration, highlighting the importance of non-perforated fins in optimizing thermal efficiency. Evaluation of various models for Case (F) demonstrated significant improvement in thermo-hydraulic performance, with Models (5) and (2) showing the best thermal performance factors, eta = 5.04 and eta = 5.13 for Re = 4000, respectively. These results highlight the effectiveness of Models (2) and (5), which have the potential to substantially enhance heat transfer within the absorber, thereby increasing the energy conversion efficiency of solar air heaters.