Abstract
Solar air collectors have been widely used in industries and agriculture because of their structural simplicity and economic feasibility. Still, their thermal performance characteristics are constrained by insufficient convective thermal exchange between the absorbing surface and the airflow. In this study, a numerical investigation and optimization of the thermal performance characteristics of the double-pass counter-flow flat-plate solar air collector are carried out using the CFD–Taguchi method. The heat and airflow under forced convection conditions have been modeled in ANSYS using a three-dimensional steady-state (CFD) model. Key factors such as mass flow rate (0.01–0.07–0.15 kg/s), channel height configurations, and material properties (copper, aluminum, and steel) have been studied. Using Taguchi analysis and ANOVA technique, an optimal combination of the parameters to enhance the thermal characteristics has been obtained. The simulation results reveal that the maximum efficiency attained is 0.531, where mass flow rate was found to be the predominant parameter accounting for 99.46% of total effects. Higher efficiency can be achieved with increased flow rate as a result of higher convection process; however, an increase in the mass flow rate decreases air outlet temperature because of a shorter exposure period. The effect of channel height and material was very small (less than 0.2%). The theoretical model has been checked using literature data; the largest error was 6.65%. From this study, it can be noticed that focusing on proper airflow management is more important than proper material selection.