Study of the performance of a solar air collector with different geometrical shapes of baffles

Abstract

In this work, an experimental and numerical study was presented on a solar air collector (SAC) in order to improve the thermo-hydraulic performance through rectangular baffles perpendicular to the air inside the channel (duct). In the experimental study, many cases were studied using different formations of baffles, after that, a numerical model was designed using Computational Fluid Dynamic CFD (Ansys Fluent 18.1) in the Reynolds range from Re = 5038 to Re = 10635, which was validated based on the experimental results. The turbulence model RNG k-ε was chosen because it gave closer results to the standard correlations of Dittus-Boelter and Modified Blasius, compared to the rest of the models. The results showed that the baffles play a major role in improving the heat transfer of these collectors, the effect of baffles on the heat transfer from the absorber plate to the air was understood through the local heat transfer coefficient along the channel and the velocity fields and their rays, as choosing the appropriate coordination of shape, angle of inclination, number and positioning play an effective role in improving the thermo-hydraulic performances