Performance Evaluation of a Triangular-Finned Absorber Plate Solar Air Heater: A Theoretical and Experimental Study

The thermo-fluid performance of triangular finned absorber plate solar air heater (SAH) can be enhanced using numerous favorable and effective techniques. These methods improve the heat transfer coefficient (HTC) at interface of the circulating fluid (fresh ambient air) and solar air collector or absorber plate. Fixing small, novel fins to the absorber plate enhances thermal performance by improving the airflow path of ambient air across the plate. Novel absorber plate design, optimized flow sections, and added turbulence via fins, ribs, or baffles enhance the performance of SAH. This investigation examines theoretical and experimental analyses on enhancing the thermo-fluid performance of a SAH by attaching a novel triangular-shaped fin design to the absorber plate and arranging the fins in an innovative pattern. The assessment of this work focused on enhancing heat transfer while minimizing the pressure drop. The system operates on solar thermal technology, utilizing heat derived from solar energy. Solar irradiance encroaches on glazing, where it's partly absorbed by the black absorber plate and fins, and partly heats the air circulating between the transparent glazing and triangular finned absorber plate. Based on this setup, various performance-related equations were derived under several simplifying assumptions. The analysis was conducted at mass flow rates (MFR) ranging from 0.010 to 0.015 kg/s, with results showing an enhanced thermo-fluid performance of the rectangular duct SAH. The maximum inlet air temperature reached 59 ºC at the lowest mass flow rate MFR of 0.010 kg/s across whole day, with the peak temperature occurring at a solar flux of 846 W/m². The heat transfer coefficient increased from 3.20 W/m²K to 13.84 W/m²K with variability in MFR and solar flux during the whole day. The assessment of this study reveals a 6.25% variation between theoretical and experimental pressure drop at the lowest MFR of 0.010 kg/s.