Thermal performance and energy saving using phase change materials (PCM) integrated in building walls

Abstract

One of the new strategies lately used in energy efficient building (EEB) is the integration of phase change materials (PCM) into the building structure. This study examines the long-term thermal behavior of a building wall that contains different types and thicknesses of PCM in the hot summer season according to the climate of Aswan in Egypt. The building wall is studied with and without the PCM layer under different exterior weather conditions. ANSYS 2020 R1 is used to design and simulate a 2D simplified thermal model. The influences of PCM types (RT-27, RT-31, RT-42, RT-35HC, RT-44HC, and lauric acid), thickness (1, 2, 3, 4, 6, and 8 cm), and location inside the wall (outer side, inner side, and the middle), as well as different cities on the inner wall temperature are studied. The results show that, using PCM in the wall structure reduces the indoor heat flux and reaches the temperature of internal walls closer to the desired levels. Additionally, RT-35HC has the highest thermal performance and the optimal place of the PCM location is 1.5 cm from the inside and outside of the wall. The average expected indoor wall temperature reached 31.1 °C, and 27.7 °C for the wall without and with PCM, respectively, based on three-month model simulations. The use of 1.5 cm inner and outer of RT35HC-PCM in the wall structure results in a 66 % reduction in the overall energy gain throughout the summer.