Enhancing thermal performance: The evolution and future of solar air heaters with baffles

Solar air heaters (SAHs) play a vital role in solar thermal utilization, yet their efficiency is limited by the low thermal conductivity and density of air. The present study aims to clarify how structural modifications, particularly the use of baffles, can enhance the thermal performance of SAHs. A comprehensive literature review was conducted to trace the development, classification, and structural evolution of baffle-equipped SAHs. The analysis reveals that incorporating baffles can effectively increase turbulence, reduce thermal boundary layer thickness, and thereby improve heat transfer efficiency. However, challenges remain regarding optimal baffle geometry, pressure drop, and cost-effectiveness. Overall, this study highlights the progress made in baffled SAH research and identifies future directions for designing high-performance and energy-efficient systems.