Heat Transfer Enhancement of Solar Air Heater using Circular Rib

The term solar air heating refers to a technology in which the radiant energy emitted by the sun is captured in an absorber and used for space heating. Needless to say, it is a renewable and pollution-free method to produce space heating, and when used in commercial buildings or industries, it could be very cost-effective. Conventional solar air heaters have low thermal efficiency because of the low heat transfer coefficient between the absorber plate and air, leading to a higher absorber temperature and hence higher thermal losses. Attempts have been made to increase heat transfer to air flowing through the solar air heater duct using finned absorbers, packed bed absorbers, corrugated absorbers, two-pass air flow, overlapped glass plates, artificially rib-roughened absorbers, etc. In conclusion, the experimental investigation carried out to collect extensive data on artificially roughened solar air heater ducts has revealed that by roughening the underside of the absorber plate of the solar air heater duct with a circular transverse rib, the thermal performance is enhanced.