| The phase change materials use the latent heat to achieve the aim of controlling the temperature.By applying phase change materials to building envelopes,the phase change material can absorb or release a large amount of heat during the phase change period and can maintain the room temperature as well as the stability of the building environment,in addition,reduce the indoor temperature fluctuations,and thereby improve the living comfort.By mixing suitable amount of microencapsulated phase change material into high-strength cement,the phase change mortar board with higher strength and higher heat capacity can be produced.Experiments show that by adding appropriate amount of phase change material,the mechanical strength of the phase change mortar board can fully meet the requirements of the envelope structure,and has high thermal performance,which can perfectly and efficiently realize the energy saving purpose of the external construction maintenance structure.The building envelopes should firstly meet the mechanical property.Investigating the influence of phase change materials with different mass fractions on the mechanical properties of phase change components,it shows that with the increase of phase change material incorporation,the compressive strength and flexural strength increase first and then decrease.The strength reaches its maximum when the amount of incorporation reaches 5%.The compressive and flexural strengths is 71.5Mpa and 15.4Mpa,respectively,8.12% and 32.76% higher than those of ordinary concrete.The more the amount of phase change materials added into the cement,the lower the hydration heat of the phase change mortar and the less the temperature cracks show up.But at the same time,the incorporation of phase change materials also brings a large number of defects,resulting in a decrease in the strength of phase change mortars.Choosing reasonable of phase change material incorporation has important effect on the thermal and mechanical properties of phase change mortar and selecting the appropriate mix ratio is very necessary in engineering applications.According to the mechanical test of phase change wallboard,three different mass fractions of phase-change materials were selected to perform the house model thermal storage experiment.Sixteen kinds of walls were designed and then investigated the effect of different combinations of phase change mortar boards on the temperature in the house.Studies have shown that when the phase change mortar board is placed in the middle of the wall,the phase change efficiency is the highest,and the PCM5,PCM15,and PCM25 efficiency are 20%,45%,and 55%,respectively.The corresponding room temperature drops by 4.5°C,5.5°C and 6.9°C,respectively.Based on the Solidworks Flow Simulation finite element analysis software,simulated the process of five kind of phase change wallboards,The results are similar to the experimental trends.The accuracy of mutualtesting and simulation shows that phase-change materials have advantages in controlling room temperature and improving the thermal environment of buildings.Analyzing the climate in Shenzhen,establishing a full-scale phase change experimental room and ordinary concrete room,monitoring the indoor temperature curve and power consumption of the two experimental rooms.In the summer and autumn seasons,phase change materials can effectively reduce the indoor temperature and reduce temperature fluctuations.Room temperature in phase change rooms in summer,spring and fall can be reduced by 5°C and 2°C,with temperature fluctuations of 2°C and 1°C.In the winter,the phase change material has little effect.Phase change materials can effectively reduce the use of electricity during the summer months and can save electricity up to 10 kwh in nine days.Electricity consumption in the spring and autumn seasons is similar to that of ordinary rooms.The Shenzhen area has only a short winter period,and the control of room temperature during the other seasons makes it suitable for phase change materials to be used in Shenzhen. |
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