Study On Moisture-proof Technology Of Phase Change Thermal Storage Materials

Since the Industrial Revolution,the human population and living standards have been greatly improved,followed by a large increase in energy consumption.However,the total amount of fossil energy on the earth is limited.For the future of mankind,it is necessary to improve the utilization of energy,and thermal storage technology can solve this problem very well.Thermal storage materials are divided into sensible heat storage materials,latent heat storage materials,thermochemical reaction heat storage materials and composite phase change heat storage materials.Among them,composite phase change thermal storage materials have been extensively studied due to their advantages of a variety of materials.However,the inorganic salt in the composites generally have strong hygroscopicity.The inorganic salt will precipitate on the surface of the samples after long-term contact with the moisture in the air.This will make the materials loose,granulated,less density and less mechanical properties,which seriously affect the service life of the materials.In order to improve the moisture resistance of composite phase change heat storage materials,magnesium oxide was used as ceramic matrix,and inorganic salts such as Na2CO3,K2CO3,Li2CO3 and potassium sodium carbonate were used as phase change materials to prepare composite phase change heat storage materials.Through different humidity experiments,the effects of the kinds of inorganic salts and the content of inorganic salts on the hygroscopicity of composite phase change heat storage materials were studied.The experimental environment refers to the average humidity in summer in most cities of China.Subsequently,the thermal physical properties and morphology of the composite heat storage material after humidity experiment were studied by DSC,SEM and thermal conductivity analysis.After studying and discussing the experimental results,the following conclusions are drawn:the hygroscopicity of inorganic salt ceramics-based composite phase change materials is mainly affected by the kinds of inorganic salts;reducing the composition of inorganic salts in composite phase change materials has little effect on the improvement of moisture resistance.In addition,the experimental results also show that the high humidity environment has little effect on the latent heat and thermal conductivity of phase change composite materials,the material can still maintain its good thermophysical properties.The final experimental results show that the main way to improve the moisture resistance of composite phase change heat storage materials at this stage is to change the types of inorganic salts.