Thermal response characteristics of composite phase change walls with different sandwich layers of sodium carbonate decahydrate/sodium hydrogen phosphate

In order to explore the improvement of thermal properties of phase change materials on wall, 35% Na2CO3·10H2O/52.5% Na2HPO4·12H2O/5% boron nitride nanoparticles/7.5% expanded graphite composite phase change materials were prepared by eutectual method, which were made into blocks and placed in different positions of gypsum board. A phase change wall which could be used to adjust indoor thermal comfort was constructed. The thermal response characteristics of the wall at different locations or at different temperatures of heat source were experimentally studied, and the reduction of CO2 emission was evaluated. The results show that with the increase of heating distance and the decrease of heat source temperature, the indoor heating rate gradually decreases, and the duartion of thermal comfort duration increases. With the heating distance of 30 cm and heating temperature of 37 ℃, the duration of thermal comfort of sandwiched phase change gypsum boards at interior side reaches 1 980 s, which is 20 s longer than that of sandwiched phase change gypsum boards at exterior side. The CO2 emission can be reduced by 379.36 kg within the recylic time of 2 371 days. Therefore, when the heating distance is longer and the heat source temperature is lower, the sandwiched phase change gypsum boards at interior side is more conducive to delaying the rising rate of the room temperature and reducing CO2 emission.