Experimental Investigation of Thermal Performance Enhancement in Vertical Absorber Solar Air Heaters Using Fins

Objectives: To compare the thermal performance of vertical absorber solar air heaters (SAHs) designed with and without finned extensions for different air flow rates (AFRs). Methods: Experimental studies were conducted between 09:00 and 16:00 in October 2024 in the Vile Parle, Mumbai, Maharashtra (19.0968°N, 72.8517°E) with four AFRs (0.0383-0.06 kg/s). Change in the temperatures, thermal efficiency and useful energy gain were measured during the experimentation. Findings: Vertical absorber with fins consistently outperformed unfinned design. Finned solar air heater achieved peak thermal efficiency of 62 % at 0.045-0.05 kg/s as compared to 50 % for unfinned SAH at 0.06 kg/s. The daily average useful power was raised to 154‛ W/unit of unfinned to 222 W/unit of finned. Finned designs provided high peak efficiencies throughout the midday and also provided high performance well in the late afternoon, especially in high flow rate. These results support the hypothesis that the geometry of absorbers has a significant impact on the heat transfer performance and energy gained. The findings are in line with literature available and shed light on the best adjustments in the flow rate and efficiency of vertical absorber systems. Novelty: The introduction of vertical absorber along with reflective glazing shows that it is possible to improve the efficiency of solar air heaters and increase the amount of energy gained by the thermal system that operate on a sustainable basis with the help of pragmatic use of fins. Keywords: Vertical absorber solar air heater, thermal enhancement, renewable energy, heat transfer enhancement