Assessment of Building Façade Thermal Performance for the Potential Application of Phase Change Materials (PCMs) in Malaysia, a Case Study

Phase change materials (PCMs) can be applied in buildings to reduce daily temperature fluctuation and shift the peak temperature occurrence, hence, providing more thermally comfortable environments. This approach helps in reducing the energy consumption associated with the use of mechanical systems. The main concept of PCMs is to absorb the extra ambient heat during the day time and reuse or remove it during the night time. Therefore, it is crucial to have an ambient temperature fluctuation in order for PCMs to efficiently work. This paper investigates the potential application of PCMs in building façade within tropical climates to reduce the overheating due to the direct solar radiations received by building façade. A building was selected to conduct measurements on its southern and northern opaque façades during the period in which the sun is facing the southern façade. Measurements included the external surface temperature (T_se), internal surface temperature (T_si) and heat flux of the selected facades, as well as the indoor air temperature (T_ai) and global solar radiation (GSR). It was found that the southern façade was highly influenced by the GSR and reached maximum T_se of 44.81 °C compared to 32.63 °C for the northern façade, which was almost constant through the measurement period regardless of GSR. In addition, the effects of the high T_se on increasing T_si and, then, T_ai was clear. Furthermore, high daily fluctuation of T_se was observed that reached up to 18 °C, which might propose a potential area for the application of PCMs to reduce the overheating caused by the direct solar radiation. Finally, analysing the T_se of the southern facade during the sunniest days indicates that the optimum transition temperatures for the PCMs selected for the application in the investigated conditions could be between the range of 30–36 °C.