Simulation Analysis of Heat Transfer and Energy Consumption in Phase‐Change Concrete Walls Under Diverse Air‐Conditioning Modes in China's Hot‐Summer and Cold‐Winter Regions

The energy consumption of buildings in China's hot‐summer and cold‐winter regions is high, and building envelope structures urgently require further optimization. Research on optimizing building envelope structures with phase‐change material (PCM) typically assumes a continuous air‐conditioning operation mode, however, in China, air conditioning often operates intermittently. Considering the changes in the specific heat capacity and thermal conductivity during the PCM phase transformation, this study compares the thermal performance and energy consumption of phase‐change concrete wall (PCCW) and ordinary concrete wall (OCW) under different air‐conditioning modes. The findings reveal that, under intermittent air‐conditioning operations 1) PCCW reduces the maximum internal surface temperature by 0.40 °C, delays the peak temperature by 15 min and 2) the indoor temperature distribution in PCCW is more uniform than in OCW, and after turning on the air conditioning, the time required for the indoor temperature to drop to the set temperature decreases by 31.50%. Moreover, buildings with a PCCW as the external wall exhibits an annual energy consumption reduction of 20.32%. This study analyzes the heat‐transfer characteristics of PCCW in hot‐summer and cold‐winter regions and their impact on energy consumption, offering a reference for the promotion and application of phase‐change walls.