Thermal and acoustic performance of masonry walls with phase change materials: A comparison of scaled-down houses in tropical climates

This article examines experimentally and numerically the effectiveness of Phase Change Materials (PCMs) and a new type of hybrid sandwich insulated panel (SIP) at improving the thermal comfort of four case study houses built in Thailand. In Phase 1 of the experimental programme, three scaled-down house units were built with either a) traditional brick walls plastered with a cement-based mortar, b) brick walls plastered with a cement-based mortar mixed with a 15% of PCMs, or c) a new SIP panel termed UWall. The results are discussed in terms of temperature, relative humidity (RH), energy consumption and acoustic performance. It was found that the PCM plastering and UWall effectively reduced the temperatures in the unit between 1 C-degrees and up to 5 C-degrees compared to the counterpart unit with brick walls plastered with cement-based mortar. In Phase 2 of the tests, a 10 x 7 m full-scale house was built with one room built with brick walls plastered with the cement-based mortar-PCM mixture, and one room built with the new UWall. Temperature, RH and indoor air movement were recorded for 48 h. Results from a bioclimatic chart indicates that both temperature and RH in the rooms remained within the comfort zone at all times if air movement is considered. The three units and full-scale house were then modelled in ANSYS (R) software to carry out a heat transfer analysis. The modelling approach was successful at predicting the maximum temperatures in the tested case study houses (accuracy <7%). For the case study houses and climate conditions considered in this study, the mortar-PCM plastering proved a practical retrofitting solution to improve the thermal performance, RH, energy efficiency and acoustic resistance of existing brick walls. Similar solutions could be adopted to improve the thermal comfort in masonry walls of existing buildings. This article contributes towards developing more effective solutions to improve the thermal comfort in existing houses and buildings located in tropical regions, which in turn can help reduce energy consumption.