Preparation And Performance Of Form-stable Composite Phase Change Materials Based On Expanded Perlite

Based on the urgent need for energy conservation in buildings in China and the low performance of existing insulation materials.The phase change storage technology is used to transform the traditional building thermal insulation material expanded perlite to prepare new building insulation materials.In this thesis,the physicochemical properties of EP was studied.A capric acid-palmitic acid eutectic mixture PCMs?CA-PA EM PCMs?having a suitable phase temperature and a high energy storage density was prepared,and the thermal performance was characterized.The EP/CA-PA-Al₂O₃ form-stable PCMs?EP/CA-PA-Al₂O₃ FS-PCMs?with high thermal conductivity was prepared by adding the nano-alumina,and the thermal performance of EP/CA-PA-Al₂O₃ FS-PCMs was characterized.The MEP/CA-PA form-stable PCMs?MEP/CA-PA FS-PCMs?with high thermal conductivity was prepared by in situ growth of graphitized carbon material in EP,and the thermal performance of MEP/CA-PA FS-PCMs was characterized.Expanded perlite is an environmentally friendly porous mineral material with rich in cellular structure.The smaller the average particle size of the EP,the higher the water absorption rate.It has good water absorption properties and resistance to hydrochloric acid attack.After treatment at a calcination temperature below 1000°C,EP can still maintain normal pore structure and microstructure.The values for the latent heat and temperature of CA-PA EM PCMs during melting were 174.4 J/g and 23.7°C,respectively,while,these values were 173.2 J/g and 19.2°C during freezing,respectively.The temperature is just within the appropriate temperature range of human life.The CA-PA EM PCMs has good temperature regulation ability in the temperature range of 20³0°C.CA-PA EM PCMs have excellent chemical stability,thermal stability and thermal cycle stability.The values for the latent heat and temperature of EP/CA-PA FS-PCMs during melting were 109.9 J/g and 21.7°C,respectively,while,these values were 108.6 J/g and 18.4°C during freezing,respectively.The adsorption capacity of EP/CA-PA FS-PCMs to CA-PA EM PCMs is 65.87%,no leakage occurs in 100 thermal cycles,and it has good chemical stability and thermal stability.The thermal conductivity of EP/CA-PA FS-PCMs at 25°C is 0.15 Wm^-1k^-1.The CA-PA-Al₂O₃ eutectic mixture PCMs were prepared by ultrasonic-assisted-physical blending process.The EP/CA-PA-Al₂O₃ FS-PCMs was prepared by vacuum impregnation process.The EP/CA-PA-Al₂O₃ 16.67 FS-PCMs have a thermal conductivity of 0.39 Wm^-1k^-1,which is 2.6 times that of EP/CA-PA FS-PCMs.For the first time,graphite in-situ modified EP was prepared by metal catalysis-anaerobic carbonization process.The modified EP/CA-PA form-stable PCMs?MEP/CA-PA FS-PCMs?were prepared by vacuum impregnation process.The thermal conductivity of MEP-3/CA-PA FS-PCMs is 0.51 Wm^-1k^-1,which is 3.4 times that of EP/CA-PA FS-PCMs.MEP/CA-PA FS-PCMs have good chemical stability,thermal stability and thermal cycling stability.