Enhancing solar air heater performance using corrugated plates and perforated baffles.

Improving the thermal performance of solar air heaters (SAHs) is essential for maximizing solar energy utilization in sustainable heating systems. This study investigates the influence of corrugated absorber plates combined with perforated baffles on the heat transfer and flow behavior of SAHs. Using three-dimensional computational fluid dynamics (CFD) simulations, various baffle layouts and pitch distances are analyzed under different Reynolds numbers to evaluate their effects on thermal efficiency, pressure drop, and overall performance. Grid independence and model validation against experimental data ensure the reliability of the numerical results. The findings demonstrate that incorporating perforated baffles significantly enhances convective heat transfer by promoting turbulence, vortex generation, and flow separation, resulting in higher Nusselt numbers and heat transfer coefficients. However, these improvements are accompanied by an increased pressure drop, requiring optimization between heat transfer enhancement and flow resistance. At Re = 5,000, Case A exhibits a 27% higher thermal performance than Case D, while the 80 mm (PF) configuration outperforms the 120 mm (PF) and 120 mm (CF) cases by 10-22%. The results provide quantitative insights into the geometric optimization of SAHs, offering a practical guideline for improving their thermal-hydraulic efficiency in renewable energy applications.