An optimization of heat transfer performance in solar air heaters using a novel discrete V rib configuration and gap

A solar air heater is a device that emits irradiation and converts it into thermal energy. Solar radiation is captured using an absorber plate that heats the air flowing over it. Providing artificial roughness is the most efficient method to increase the performance of solar air heaters. The present study introduces a novel discrete V-shaped rib design with gaps to increase SAH efficiency. This design aims to improve heat transfer by disrupting the laminar boundary layer. Key parameters explored include a relative roughness height of 0.043, a relative roughness pitch of 10, an angle of 60 degrees, a gap of 0.5 in the center between adjacent ribs, a variation in the number of gaps from 1 to 4, and a Reynolds number ranging from 3000 to 14,000. This range suggests a shift from transitional to turbulent flow within the SAH. The study reported a significant enhancement in heat transfer efficiency, with the peak Nusselt number increasing to 4.113 and the highest friction factor going up to 3.91 when using a roughness pitch of 10 and a three-gap configuration. The results indicate that the innovative V-rib structure with gaps performs superior to existing rib geometries, representing a significant step forward in SAH design. Such improvements could lead to the developing of highly efficient SAHs, contributing to the wider adoption of renewable energy solutions.