A simulation-based evaluation of using PCMs in buildings for energy efficiency under different climate conditions

Today, majority of energy consumed in buildings is used to provide thermal comfort conditions. Reducing heating and cooling loads to provide comfort conditions in buildings is possible by taking the right passive design decisions concerning the variables that affect these loads. The building envelope which seperates indoor environment from the outdoor environment and affects the development of indoor thermal comfort conditions is the most important determining factor for energy loads in buildings. In this study, after applying PCM on the building envelope and inner walls and inner floors annual heating, cooling and total energy consumptions and indoor environment comfort conditions in the zones were evaluated. The study was done for Istanbul representing temperate humid climatic zone and for Diyarbakir representing hot-dry climatic zone in the same degreeday region according to the TS825 standards. The residential building simulated for calculations is a 3 storey building with a rectangle floor plan and flat roof and the dimensions of these buildings are 10 m x 30 m x 9 m. The building comprises 9 zones and the building coverage is 300 m2. In order to reduce the difference in energy consumption and thermal comfort conditions among the zones due to their different locations, PCM was applied on inner walls and inner floors in addition to the building envelope to develop a range of alternatives. Annual energy performance evaluation and calculation of daily operative temperature values for January 21 which represents the heating period and July 21 which represents the cooling period were done by the EnergyPlus simulation tool. According to the calculations, the total energy load of the building in the A4.2 alternative where PCM was applied on the building envelope and on inner walls and inner floors was reduced by 11.96 % and 9.69 % in Istanbul and Diyarbakir respectively. With the alternatives, differences in energy consumption among the zones were reduced but not eliminated. Operative temperature values in the zones changed by 1.04 degrees C - 3.32 degrees C in Istanbul and by 0.87 degrees C - 1.16 degrees C in Diyarbakir with the PCM application contributing to the improvement of indoor comfort conditions.