The Research On Preparation And Thermal Performances Of Inorganic Organic Form-stable Phase Change Materials

In this study, we choose calcium chloride hexahydrate CaCl2·6H2O, stearic acid（C18H36O2）and lauryl alcohol（C12H26O）as phase change mareials (PCMs), which possesshigh phase change enthalpy (192J/g for Calcium chloride hexahydrate,199J/g for stearicacid and207.3J/g for lauryl alcohol). Therefore, they have good ability of thermal storageand can be used as a new kind of phase change materials with good application prospect inthermal storage.In order to solve the problem of flowability of phase change material in related phasechange process, we have prepared calcium chloride hexahydrate/multiporous aluminacomposite and stearic acid-lauryl alcohol/expanded graphite composite phase change material.Then their microscopic structure and thermodynamic properties were studied and discussed,and the results are summarized as follows:CaCl26H2O/porous Al2O3composite phase change materials have good thermalperformance, phase change enthalpy of the best ratio of the sample (the ratio of calciumchloride hexahydrate is71.4%) can reach to99.81J/g. Its microstructure tests showed thatthe porous alumina serves as a good supporting, Calcium chloride hexahydrate can beadsorbed by porous alumina and controlled in the pore structure.In order to regulate and control the phase transition temperature into suitable range for humanlife, stearic acid(phase transition temperature is69.4oC) and dodecanol (phase transitiontemperature is23.1oC) were mixed in different proportions, and examined for theirthermodynamic properties. Test results show that the temperature of the phase changecomposite material can be adjusted to24.871oC, and the corresponding phase changeenthalpy to be177.609J/g(the proportion of stearic acid and lauryl alcohol is1:3), and cankeep good thermal performance after several phase transition cycles. The study also foundthat the Initial weight loss temperature of phase change composite material is apparentlygreater than dodecanol. Therefore, the method mixed stearic acid and dodecanol in differentproportions can not only obtain a phase change material with better thermal storageperformance, but also improve the thermodynamically stability performance of a single phasechange material.Preparation of different proportions of stearic acid-dodecanol/expanded graphite phase change composite materials can make use of the physical adsorptioncharacteristics of expanded graphite. the adsorption capacity and the thermodynamicperformance of the composite phase change materials were optimized. The results show thatthe adsorption capacity of expanded graphite can reach90%. Due to nucleation effect, phasechange composite material shows higher latent heat（179.6J/g）.