Preparation and properties of expanded graphite based phase change energy storage materials
The expanded graphite-paraffin composite phase change energy storage material was prepared by vac-uum impregnation method,with expanded graphite as the main thermal material and paraffin as the phase change heat storage material.The effect of paraffin mass fraction on the microstructure,phase structure,and thermal performance of composite phase change energy storage materials were studied.The results indicate that the composite phase change energy storage material generated by the reaction of expanded graphite and paraffin mainly relies on physical adsorption and binding,and paraffin evenly covers the surface and pores of expanded graphite.When the mass fraction of paraffin is 91%,the sealing and structural density of the composite phase change energy storage material are the best,with almost no leakage.As the mass fraction of paraffin increases,the melting point of composite phase change energy storage materials gradually increases,and the thermal de-composition temperature gradually increases.The thermal decomposition temperature of composite phase change energy storage materials with 91%paraffin mass fraction is about 15℃higher than that of phase change materials with 85%paraffin mass fraction.As the mass fraction of paraffin increases,the thermal conductivity and thermal diffusion coefficient of composite phase change energy storage materials continue to decrease,the density first decreases and then increases,and the specific heat continues to increase.When the mass fraction of paraffin is 91%,the density of the composite phase change energy storage material is the minimum value of 0.794 g/cm3,corresponding to a specific heat of 5.462 J/(g·K).Analysis shows that the composite phase change energy storage material with a paraffin mass fraction of 91%has the best comprehensive performance.
expanded graphiteparaffinphase change energy storage materialsphysical adsorptionthermal per-formance
万方数据
维普
