Thermal Performance Analysis of a Double-Pass Solar Air Heater with Discontinuous W-Shaped Ribs

Experiments were done on a two-pass solar air heater (SAH) to see the consequence of discontinuous w-shaped ribs on the Thermal characteristics. The absorber plate has discontinuous w-shaped ribs on both sides, with the upper portion painted black to absorb more radiation. Dittus-Boelter and Modified Blasius equations are used to create a rectangular duct and confirm its validity. In this paper, the variation of Thermal and Thermohydraulic/effective efficiency is shown against Reynolds Number. For the analysis, the relative roughness pitch (p/e) ranges from 5 to 20 The relative gap width is taken as 0.5. The angle of attack (α) is taken as 45° and 75°. The Reynolds Number for the experiment was taken from 4900 to 12,000. It has been observed from the experiments that the maximum efficiencies were found out at a relative roughness pitch of 10 with their values a bit higher in the case of 75° than in the case of 45° due to change in its turbulency.