Experimental and Numerical Investigation of Heat Transfer Characteristics of Double-Layer Phase Change Walls for Enhanced Thermal Regulation in Summer Climates

Abstract

This study employs the effective heat capacity method within the COMSOL simulation framework to analyze the thermal performance of double-layer phase-change walls under typical summer climatic conditions in Zhengzhou, Henan Province. The model considers a wall structure with a total thickness of 100 mm and a height of 300 mm, where the exterior surface represents the outdoor environment, the interior surface represents the indoor environment, and the top and bottom boundaries are assumed to be adiabatic. A highly refined triangular mesh ensures numerical stability and solution accuracy. Special attention is given to the influence of Micro-PCM content on thermal storage characteristics. Simulation results demonstrate that increasing the Micro-PCM content substantially enhances the thermal regulation capacity of the double-layer phase-change walls. At a Micro-PCM volume fraction of 15%, the peak temperature of the double-layer phase-change wall is reduced by 4.33 °C compared to a conventional wall, while the attenuation factor increases to 16.88. Furthermore, the mean thermal delay extends to 440 min, the temperature amplitude decreases to 1.13 °C, and the peak instantaneous heat flux is reduced to 13.24 W/m2. These findings highlight the significant latent heat storage capacity and superior thermal modulation performance of double-layer phase-change walls, offering a valuable technical reference for the design of energy-efficient building envelope systems.