Optimizing air-layer thickness for enhanced thermal regulation in dynamic PCM wall systems: An experimental study

This study experimentally examines how air‐layer thickness in a dynamic PCM-enhanced wall affects summer thermal performance and identifies the best configuration for regulation. Five configurations were tested, including a static PCM wall and four dynamic PCM systems with different air layer thicknesses (0, 1, 3, 5, and 7 cm). Experimental results indicate that the air layer thickness has a significant impact on temperature amplitude reduction and heat flux variation in the dynamic PCM system. Key performance metrics—interior surface temperature fluctuations, peak temperature delay, heat flux changes, and total heat load—were measured and compared to the static case. The results reveal that the 5 cm air layer provides the greatest benefits: a 62.8% decrease in interior surface temperature swings and a 1.25-hour delay in peak temperature compared to the static PCM; a 53.3% reduction in interior heat flux fluctuations; and the lowest heat gain at 9.95 kJ, which corresponds to a 70.1% decrease in total wall heat load. These findings highlight the critical role of air-layer design in dynamic PCM systems and provide data-driven guidelines for adaptive envelope solutions in warm climates. • An experimental study identifies the optimal air-layer thickness for dynamic PCM-integrated walls under realistic boundary conditions. • A 5 cm air layer achieved the best thermal regulation, reducing interior surface temperature swings by 62.8% and delaying peak temperature by 1.25 h. • Dynamic PCM walls with optimized air layers cut interior heat flux fluctuations by 53.3% and reduce total heat load by up to 70.1%.