Performance Evaluation of Phase Change Materials to Reduce the Cooling Load of Buildings in a Tropical Climate

Abstract

Tropical region such as Darwin has similar weather patterns throughout the year, thus creating higher energy demands in residential buildings. Typically, buildings consume about 40 per cent of the total energy consumption for indoor heating and cooling. Therefore, building envelopes are linked with design strategies such as the use of thermal energy storage and phase change materials (PCM) to minimize this energy consumption by storing a large amount of thermal energy. Primarily, PCMs are targeted by researchers for use in different components of buildings for thermal efficiency; thus, this study aimed to provide a suitable PCM to optimize indoor thermal comfort and minimize the cooling loads of residential buildings in tropical climates through simulation of a tropical climate building and provide optimum thickness for the selected material. Microencapsulated PCM mixed with gypsum in wallboards were used to reduce the cooling load of a building located in Darwin. The cooling load of the building was calculated using Revit software. A comparison of the cooling load of the building was carried out using PCM-incorporated wallboards of thicknesses of 0 cm, 1 cm and 2 cm in Energy Plus software. The total cooling load decreased by 1.1% when the 1-centimetre-thickness was applied to the wall, whereas a 1.5% reduction was obtained when a 2-centimetre-thick PCM layer was applied. Furthermore, the reduced cooling loads due to impregnation of the PCM-based gypsum wallboard gave reduced energy consumption. Ultimately, the 2-centimetre-thickness PCM-based gypsum wallboard gave a maximum reduction in cooling load with a 7.6% reduction in total site energy and 4.76% energy saving in USD/m2/year.

Numerical Assessment of Different Phase Change Materials as a Passive Strategy to Reduce Energy Consumption in Buildings under Tropical Climates

“…Neglecting volume distribution, the perimeter of the considered PCM layers is also nearer to the inside surface. This match was mentioned in Jia et al [17], but it is contrary to the conclusions of other authors [18,20,25]. However, also in [18,20], it was established that PCM layer location has very little influence on energy savings, as long as the same PCM is considered.…”

“…This match was mentioned in Jia et al [17], but it is contrary to the conclusions of other authors [18,20,25]. However, also in [18,20], it was established that PCM layer location has very little influence on energy savings, as long as the same PCM is considered. Nonetheless, in reviewed studies, the presence of the PCM layer in the envelope layout is much smaller than that considered in this study.…”

“…However, among the four considered locations, external PCM layers tend to provide better energy savings at higher thicknesses, in contrast to internal layers, which seem to provide more energy savings at smaller thicknesses. Sangwan et al [18] also showed that PCM external-wall side layers provide a lower cooling load. However, the results showed that internal wall-side PCM layers establish a slight extra energy consumption reduction in walls compared to external ones, although external ones provide the lowest net energy consumption.…”

“…This is an open software made by the U.S. Department of Energy (DOE) for building energetic simulations. As an open software, it is accessible for adapting to personalized interfaces or coupling with other softwares: Sarri et al [16] carried out a simulation-based optimization by coupling EnergyPlus and GenOpt tools to determine the optimum melting temperature of PCM when applied to buildings in different Algerian climatic zones; Jia et al [17] used EnergyPlus to study the possibilities of improving the thermal performance of prefabricated buildings in different climates by adding PCMs; Sangwan et al [18] also modeled a tropical building, but using Revit software to calculate cooling load, and EnergyPlus to figure out the optimal PCM thickness for energy savings. DesignBuilder [9] is also a widely used program based on En-ergyPlus but with a more comfortable interface.…”

“…These reduction scenarios correspond to reductions in peak temperature from 7.36% to 9.18%. Bimaganbetova et al [18] simulated a two-floor residential in eight different tropical climates. Applying the PCM layer can reduce peak temperatures up to 3.28 • C. Moreover, temperature fluctuations are reduced from a range between 5.51 • C and 7.34 • C to a range between 2.30 • C and 4.37 • C. This represents that PCM can reduce peaks and fluctuations in buildings.…”