Numerical building energy simulation with phase change materials including hysteresis effect for different square building cases in a semi-arid climate

Phase change materials (PCM) have captured the interest of researchers in the building sector. As these PCMs could provide a passive temperature regulation, which will help in reducing the energy consumption of Heating, Ventilation and Air-Conditioning (HVAC) units. The implementation of PCMs in buildings requires an encapsulation to ensure no leakage occurs during phase change. The need to assess the energy savings of the PCMs at different building volumes is necessary, so that we can have an idea about the energy savings, cost and payback period of this passive thermal regulation solution. Hence, this paper will evaluate and compare 4 different building volumes in a semi-arid climate with the use of the EnergyPlus simulation engine for the commercial PCM RT 28. These four different building volumes are the following, a 10 m x 10 m, 9 m x 9 m, 8 m x 8 m and 7 m x 7 m square building with a respectively story height of 3 m, 2.7 m, 2.4 m and 2.1 m. The chosen story heights were carefully selected to maintain a constant length to height ratio throughout the different square building volumes. Thus, the main objective of this study is to assess the indoor air temperature fluctuation reduction, the PCM energy savings and the payback period for these different building volumes. The results reveal a great temperature regulation during the summer periods with a maximum temperature fluctuation reduction of 557.7 °C for the 7 m square building. In addition, the most energy efficient building was found to be the 10 m x 10 m x 3 m square building, which was able to save an annual energy of 1600.44 kWh with a low return payback period of 22.38 years.