Numerical Simulation of a Single-Pass Parallel Flow Solar Air Heater with Circular Fins Using S2S Radiation Model

Solar air heater (SAH) is a heat exchanger device that converts solar radiation into thermal energy, using solar thermal technology (energy from the sun is trapped and absorbed to heat the air). The conventional SAH is inefficient due to poor heat transfer characteristics from the absorber. In this present study, a parallel flow SAH consisting of circular fins attached to the absorber is designed to enhance the heat transfer rate. Computational fluid dynamics (CFD)-based numerical simulation is carried out in ANSYS Fluent using the k–ɛ turbulence model with enhanced wall treatment for different mass flow rates and different solar radiation intensities. The simulation output is validated using experimental results which are available in the literature. The heat transfer characteristics, absorber, and outlet air temperature are shown using contours. The mean deviation in the outlet air temperature predicted by the simulation is found to be ~7%. The simulation and experimental results conclude that surface-to-surface radiation model can accurately predict the fluid flow behavior inside the SAH.