Performance Enhancement of a Solar Air Heating Device Featuring Wavy Absorbing Plate with Cylindrical Fins: An Experimental and CFD Study

To augment the performance characteristics of a solar thermal collection device (STCD) for heating air, the present work utilizes the integration of cylindrical pin fins over a wavy absorbing surface. This unique combination has led to a superior heat transfer rate augmentation, while maintaining low levels of associated drop in pressure. With the imposition of a uniform 1 kW/m2 heat flux at the upper portion of the absorbing surface, the important parameters like thermo-hydraulic performance index (THPI), along with Nusselt number and friction factor, are studied thoroughly. The height of the cylindrical fin is taken to be 21 mm. Wavelength and amplitude of the wavy receiver surface are taken to be 137.5 and 17.18 mm, respectively. Reynolds number is altered in the range of 3,500–16,000. A three-dimensional simulation is performed in ANSYS FLUENT 23 using RNG k-ε turbulence model. An experimental set-up is developed to perform the experimentations to validate the solver. The performance of the proposed STCD is compared with other attractive designs recently reported in the literature and found to yield better results. The highest THPI of 2.14 is achieved, which establishes the superiority of the design based on hydraulic and heat-transmission performance.