Thermal performance and properties analysis of a building envelope integrated with phase change material for energy conservation in a tropical climate region

The household sector consumes the largest amount of energy compared to other sectors in Indonesia. The most consuming instrument is the air conditioning (AC) system, as the tropical climate of Indonesia yields outdoor temperature that is higher than the standardized temperature for thermal comfort. Phase change material (PCM) possesses the potential to reduce the employment of energy for the AC system by reducing the total envelope heat transfer rate incorporated into a building through the walls. However, the selection of PCM and its integration configuration with the building materials are subjected to the climate environment. This study examined the thermal performance of some PCMs that are integrated with lightweight concrete through numerical simulation using EnergyPlus software. The integration of lightweight concrete with a PCM titled RT 35 manufactured by Rubitherm Technologies GmbH company yields the highest envelope heat gain transfer rate reduction. Meanwhile, the middle-layer placement of the PCM performs better than the configurations that placed the PCM on the wall's outer and inner surface. This is due to the PCM being imposed on a smaller temperature difference with its surroundings. Analysis of the thermal properties of the 20 mm thick PCM RT 35 placed on the middle layer of the walls yields the thermal resistance value of 0.141 m2-K/W.