Performance enhancement of a double-pass solar air heater with a shot-blasted absorber plate and winglets

A double-pass solar air heater (DPSAH) with shot blasting and winglets in the air passage is a recommended cost-effective design development to enhance thermal performance. Three different absorber plate configurations for DPSAHs were experimentally tested: (a) V-corrugation with shot blasting, (b) V-corrugation with shot blasting and a 4-3 winglet pattern, and (c) V-corrugation with shot blasting with a 3-2 winglet pattern. Furthermore, aluminum winglets were welded to the DPSAH absorber plate to increase the channel turbulence to enhance the heat transfer performance. The pressure drop and thermal performance of the DPSAHs with and without winglets were investigated using meteorological parameters such as ambient temperature, wind speed, solar irradiance, and interior temperature at regular time intervals. V-corrugation with 4-3 winglets has a maximum thermal efficiency and pressure drop of 49.5 % and 230 Pa, respectively, at a mass flow rate of 0.02 m/s. Results showed that the thermal efficiency of V-corrugation with 4-3 winglets was improved by a maximum of 7 % compared with the V-corrugation air heater. Finally, increasing the mass flow rate from 0.01 kg/s to 0.02 kg/s increases the pressure drop by 1.22 times for the V-corrugation and 1.3 times for the V-corrugation with 4-3 winglets. Furthermore, a complete economic study of DPSAHs for India is examined in this article.