Research On Preparation And Thermal Performance Of Shape-stabilized Phase Change Concrete

As a new building material,shaped-stabilized phase change concrete has the advantages of good heat storage function,good thermal insulation performance and light weight.Applying Shape-stabilized phase change concrete to building envelope can absorb and release the heat in the environment in the form of phase change,so as to reduce building energy consumption and improve the comfort of indoor environment.In this thesis,phase change materials,adsorption carriers and packaging materials suitable for shaped-stabilized phase change concrete envelope are selected.From the point of view of test,the preparation method of shaped-stabilized phase change concrete is optimized.The effects of the content and gradation of shaped-stabilized phase change particles on the properties of shaped-stabilized phase change concrete are studied.The effect of the gradation of shaped-stabilized phase change particles on the thermal conductivity of shaped-stabilized phase change concrete is emphatically analyzed.Finally,using De ST-h building energy consumption software,the building energy consumption of finalized phase change concrete envelope residence and traditional structure residence is compared and analyzed.Through experimental research,theoretical analysis and software simulation,the following conclusions are obtained in this thesis:(1)When the mass ratio of capric acid to myristic acid is 6:4,the thermal performance of the composite phase change material formed by heating and melting of the two is the best,the phase change temperature is 26℃,and the phase change enthalpy is 131.82J/g.For expanded perlite,the reasonable vacuum adsorption time is 4 min and the adsorption rate is about 600%.The shaped-stabilized phase change particles encapsulated with cement paste have no agglomeration,and the mass loss rate after 50 phase change cycles is 1.2%,which is suitable for encapsulating shaped-stabilized phase change particles.(2)In terms of performance,the compressive strength and flexural strength of shaped-stabilized phase change concrete did not decrease significantly,the thermal conductivity decreased to a certain extent,and the specific heat capacity increased to a certain extent.In the shaped-stabilized phase change concrete with sand replacement rate of 30%,the compressive strength and flexural strength of and shaped-stabilized phase change concrete decreased the most.The maximum amount of compressive strength and flexural strength is shaped-stabilized phase change concrete which the particle grading of 2～3mm,3～4mm,4～5mm,5～6mm,6～7mm,7～8mm and 8～10mm is account for 12%,14%,15%,16%,19%,20%,4%.Large sized shaped-stabilized phase change particles have a positive effect on reducing thermal conductivity,and the degree of influence increases with the increase of sand replacement rate of shaped-stabilized phase change particles.The shaped-stabilized phase change particles with medium particle size are most conducive to improve the specific heat capacity of shaped-stabilized phase change concrete.(3)The shape transformation particle gradation has good self similarity in statistical sense.The fractal dimension of 7 groups of grading is between 0.4924 and 1.6812.The larger the fractal dimension is,the denser the particles are.The grey correlation theory can better analyze the effect of particle size matching of shaped-stabilized phase change on the thermal conductivity of shaped-stabilized phase change concrete.The increase of fractal dimension of shaped-stabilized phase change particles can enhance the thermal conductivity of shaped-stabilized phase change concrete.2～3mm,3～4mm,6～7mm and 7～8mm shaped-stabilized phase change particles can enhance the thermal conductivity of shaped-stabilized phase change concrete.4～5mm,5～6mm and 8～10mm shaped-stabilized phase change particles can inhibit the thermal conductivity of shaped-stabilized phase change concrete.(4)The performance parameters of shaped-stabilized phase change concrete prepared in this thesis are used to analyze the building energy consumption.Compared with the ordinary concrete envelope,the annual cumulative heat load of the residential model using the shaped-stabilized phase change concrete envelope is reduced by 1.5%,and the annual cumulative cooling load is reduced by 1.6%.shaped-stabilized phase change concrete can play a good energy-saving effect.