Influence of submerged impingement jet designs on solar air collector performance

The present study experimentally investigates the solar air heater performance employing submerged impinging jets ( SAHSIJ ) . The submerged jets produce high flow velocities, leading to significant turbulence aided by shear forces at the heated surface, resulting in increased and evenly distributed heat removal rates. The study explores the impact of geometric parameters viz jet spacing ratio (Sj /Dh) from 0.108 to 0.433, jet angles (alpha) from 75 degrees to 90 degrees jet diameter ratio (d /Dh) from 0.043 to 0.076, span-wise pitch ratio (Y /Dh) from 0.43 to 1.08 and stream wise pitch (X /Dh) from 0.43 to 1.73 on the Nusselt number and friction performance to enhance the overall efficacy of the system. To evaluate the effectiveness of the new SAHSIJ design in terms of thermal and thermohydraulic performance, the results are compared with those from a smooth duct solar air heater. The results show that the novel solar air heater with submerged pipe jet significantly outperforms the smooth duct solar air heater in terms of heat removal from the absorber plate. SAHSIJ achieved a thermal efficiency (eta th) of 75.3 % and a thermo-hydraulic efficiency ( eta eff ) of 69.2 %, with a thermo-hydraulic performance parameter (eta) of 3.19.