Research On Preparation Of Shape-stabilized Phase Change Energy Storage Gypsum And HeatTransfer Performance Of Wall

As a big energy consuming country,china needs about 2 billion square meters of total building area every year,accounting for half of the global total building volume.In addition,china's total energy consumption is gradually increasing,accounting for about 1/3 of the total social energy consumption.and with the continuous improvement of people's living standards,china's building energy consumption will always maintain the growth trend.In this case,building energy saving becomes more and more important.In this paper,organic acids are used as phase change materials to prepare binary composite phase change materials.binary composite phase change materials are made into shaped phase change materials by matrix adsorption,and then shaped phase change materials are mixed with desulfurization gypsum to make shaped phase change energy storage gypsum,which is applied in building wall insulation,on the basis of realizing solid waste utilization To further achieve the effect of energy saving.on the basis of the current research status at home and abroad,this study mainly focuses on the problems of phase change energy storage materials in the actual building application,and makes in-depth research on the proportion of phase change raw materials,the preparation of shaped phase change materials,the preparation of shaped phase change energy storage gypsum and its application in building structure(1)Firstly,different ratios of decanoic acid palmitic acid binary composite phase change materials were set by"step cooling curve method"and"differential scanning calorimetry",and then their thermophysical properties were analyzed,and the best ratio of decanoic acid palmitic acid binary composite phase change materials was selected.when the mass ratio of decanoic acid and palmitic acid was 7:3,they formed a low eutectic system,and the low eutectic system was formed The temperature corresponding to the lowest point of melting system temperature is 26?.(2)By testing adsorption rate and mass loss rate,according to the results,we can know which adsorption material and packaging material are the best.the adsorption capacity of expanded perlite is incomparable to that of ceramsite.the encapsulation effect of styrene acrylic emulsion was superior to that of EVA emulsion,and the decanoic acid palmitic acid stabilized phase change material was prepared.(3)Taking desulfurized gypsum as cementitious material and mixing with shaped phase change material according to different proportions,shaped phase change energy storage gypsum was prepared.the specific heat capacity,thermal conductivity and compressive strength of the gypsum were tested respectively.the specific heat capacity of phase change energy storage gypsum was about twice that of ordinary gypsum,and the heat storage performance was relatively better.With the addition of shaped phase change materials,shaped phase change energy storage gypsum shows its own advantages.without affecting the mechanical properties,the thermal conductivity decreases and the heat storage effect increases.(4)The fixed phase change energy storage gypsum was applied to the internal insulation of building wall,and its heat storage effect was tested.then the actual house model was established by using the finite element software ANSYS to explore the influence of phase change material on indoor temperature fluctuation.The results showed that the heat flow rate decreased from 61.2w/m~2 to below 40W/m~2 after passing through the fixed phase change energy storage gypsum,which indicated that the fixed phase change energy storage gypsum board absorbed heat A large amount of heat is converted into phase change latent heat,which can realize heat storage effect.(5)Based on this theory,the phase change energy storage wall model is designed,and the heat transfer model of the wall is established by the finite element analysis software ANSYS.the temperature distribution and temperature change of the wall structure layer are deeply analyzed in the stage of heat storage and release.at the end of heat storage,the phase change material is completely melted,and the temperature of the phase change material layer on the wall surface remains at 25.82?,which means that the heat storage effect of the shaped phase change material is achieved,and the peak temperature of the inner surface of the wall is about 2 hours later than that of the outer surface of the wall,which again shows that the addition of shaped phase change energy storage gypsum can improve the energy saving of the building and the comfort of living.