Study On The Influence Of Phase Change Materials On The Performance Of Lightweight Enclosure Structures

With the vigorous development of China’s construction industry,the energy consumption of residential and commercial buildings is increasing day by day.The problem of high energy consumption and high carbon emissions in China’s buildings needs to be solved urgently.BNEF(Bloomberg NEF)researches shows that China’s residential and commercial building air-conditioning power consumption of 657 trillion watts in 2018,accounting for 34%of the world’s air-conditioning power consumption,reducing air-conditioning power consumption is the key to reducing building energy consumption.As a new type of clean energy storage material,phase change material can absorb or release a large amount of heat during the phase change process,which can adjust the thermal environment inside the building to reduce the electric load of building air conditioner and save building energy.Therefore,phase change materials have very good research and application prospects in building energy conservation.This paper selects a light envelope structure in Changsha as the research object,and tests the thermal performance of the building using phase change materials.The experimental results show that the phase change material installed inside the outer wall of the building increased the indoor air peak temperature of the building and the indoor average temperature at night from 26.6℃ and 8.7℃ to 27.6℃ and 9.5℃,respectively.Installed the phase change material on the outside of the outer wall,the indoor air peak temperature is 0.5℃ lower than the reference building.Installed the phase change material on the inside or outside of the outer wall increased the fluctuation of the heat flow inside the inner wall of the building.In addition,thermal performance and energy simulations were performed on the test building by using EnergyPlus.The results show that the average room air temperature of the building with the phase change material installed outside the outer wall is reduced by 0.81℃during the office hours in summer.In the winter,the phase change material is installed inside the outer wall of the building reduced the average indoor air temperature by about 0.3℃,installed the phase change material on the outside of the outer wall reduced the average indoor temperature during the daytime office hours by 0.6℃,and the building using pure XPS insulation board has better insulation performance in winter.Considering the influence of the position of the phase change material in the outer wall,the building orientation,the outdoor air relative humidity,the outdoor wind direction and the wind speed,the EUI(Energy Use Intensity)of the building with the phase change material concentrated on the inner side of the south outer wall is the lowest,and the energy saving rate is 2.8%.For the whole year condition,the outdoor relative humidity is higher,the lower the EUI of the building is;when the outdoor wind is set to be south wind with 6 m/s wind speed,buildings have the lowest EUI throughout the year.Finally,this paper conducts an economic analysis of the various application methods of phase change materials studied in buildings.The best application method in this study is to centrally arrange phase change materials on the inside of the west wall of the building.This solution can save 3.8 yuan/square meter per year building operation costs,and the investment recovery period is 8.2 years.