Thermohydraulic performance of double pass solar thermal collector with inline, staggered and hybrid fin configurations

Abstract

Abstract The present experimental and numerical investigations are aimed to increase the thermal performance of a finned absorber plate solar air heater. A commercial CFD tool is used to perform the numerical investigation and the obtained results are validated with the experimental data. The geometrical parameters such as fin angle (30o ≤ θ ≤ 90o), fin length (0.007 m ≤ L1 ≤ 0.028 m), fin height (0.007 m ≤ L2 ≤ 0.014 m), fin arrangements (inline, staggered, and hybrid), and hydraulic diameter (0.029 m ≤ Dh ≤ 0.057 m) of the heater duct are considered to obtain the optimum values using numerical simulation, while Reynolds number (3000 ≤ Re ≤ 20, 000) as a flow parameter is considered. The obtained CFD results revealed the best thermohydraulic performance for the hybrid staggered fins configuration and found to be about 3.5% and 3.8% in comparison to the staggered and inline fins configuration, respectively. Moreover, CFD investigation revealed the interesting results about the staggered fins configuration, which is the generation of the wavy motion inside the heater duct that confers the significant heat transfer enhancement. Whereas, the experimental thermohydraulic efficiency of the double pass solar air heater design is found to be 79% which is about 13% higher than that of similar design of single air pass.