Improving the Heat Transfer Performance of a Solar Air Heating Duct with Semicircular Grooves on a Wavy Absorber Plate

Solar air heater (SAH) is a simple device for harnessing the solar power for heating air. The introduction of various fins, grooves, etc. on the absorbing plate increases the effectiveness of the SAH. The numerical analysis for achieving the effective performance of a SAH is studied in the current work. Semicircular grooves of 30 mm diameter are introduced in the wavy absorber plate of the SAH. The amplitude and wavelength of the wavy-shaped absorber plate are 17.19 mm and 137.5 mm, respectively. Along with the thermo-hydraulic characteristics of the SAH, the temperature and the velocity variation have been analyzed for varying Re between 3500 and 16,000. For the steady state 2-D flow study, a continuous heat flux of 1000 W/m2 is provided to the upper portion of the absorber plate, and the analysis is carried out in ANSYS FLUENT 23.0. The highest THPF is obtained to be 1.87 when the Re is 16,000. The introduction of semicircular grooves on the wavy absorber plate leads to better performance than the conventional SAH.