Numerical investigation on the performance of the solar air collector using jet impingement with W-shaped arrangement

Solar energy is a clean, abundant renewable energy source. Solar air heaters (SAHs) are essential for space heating due to their low cost and simplicity. However, improving their thermal efficiency remains an area of significant interest. The jet impingement method effectively enhances heat transfer from the absorber plate to the working fluid. In this study, the thermal behavior of heat transfer in a SAH with an absorber plate combined with impinging jets is numerically investigated. Thermal performance was evaluated using a three-dimensional CFD simulation with the k-ε turbulence model in ANSYS Fluent 19.2. The arrangement of the impingement jets is W-shaped and accordingly, the study was conducted in two phases. Two aspect ratios were considered, including AR 1 = p/h and AR 2 = h/p, where p and h represent the pitch and vertical distance of the jet arrangement. In the first phase, three aspect ratios of AR 1 = 0.75, 0.83, and 0.92 were analyzed while maintaining a constant vertical distance (h = 120 mm) between the jets. The results showed that AR 1 = 0.75 (p = 90 mm) at Re = 7500 exhibited the highest thermal performance among all examined models and Reynolds numbers. With an 80 % increase in Reynolds number (from Re = 7500 to Re = 13,500), the thermal performance of AR 1 = 0.75 declined by approximately 8.33 %. In the second phase, three aspect ratios of AR 2 = 0.88, 1.11, and 1.33 were analyzed while keeping the horizontal jet distance constant (p = 90 mm). The findings illustrated that AR 2 = 1.33 demonstrated the highest thermal performance among all tested models and Reynolds numbers. As AR 2 decreased by 16.54 % and 33.83 %, the thermal performance dropped by approximately 1.67 % and 4 %, respectively, at Re = 7500. • Thermal behavior of a solar air heater with jet impingement was studied numerically. • Two aspect ratios in W-shaped arrangement were evaluated under different Re values. • At Re = 7,500, AR 1 = 0.75 (p = 90 mm) had the highest thermal efficiency. • AR 2 = 1.33 showed the best thermal performance, decreasing as AR 2 was reduced. • Findings help enhance jet configurations for better heat transfer in SAHs.