The Preparation And Characterization Of Thermal Conductivity Enhanced Expanded Perlite/PEG Phase Change Materials And Its Application In Fly Ash Thermal Storage Brick

Building energy-saving occupies important position in people's awareness of energy conservation and environmental protection,and the construction of energysaving buildings has been paid more attention.As one of the largest industrial solid wastes in China,fly ash has played an indispensable role in the field of building materials.The combination of phase change materials and fly ash can not only solve the environmental pollution caused by fly ash,but also endow novel wall materials with high thermal storage performance,thus achieving dual benefits of environmental protection and energy saving and emission reduction.In this paper,the preparation process parameters of composite phase change materials based on expanded perlite was explored,the preparation and performance of Cu nanoparticles and graphite powder heat conductive reinforced composite phase change materials,and the preparation and performance of thermal storage bricks made of composite phase change materials doped with fly ash were characterized.The load of PEG in the PEG/EP PCMs prepared by vacuum impregnation reach 72.61%,which is 1.22 times higher than that of the sample prepared by non-vacuum impregnation,and the latent heats reaches 142.8 J/g,which increased 19.60% than that of the samples prepared by non-vacuum impregnation.The samples obtained by vacuum impregnation can load more PEG,have higher enthalpy of phase change,and can also store more latent heats.Cu nanoparticles were used as thermal conductive filler to prepare PEG-Cu composite by ultrasonic dispersion in melted PEG,and then PEG-Cu/EP PCMs was prepared by vacuum impregnation.The latent heats of PEG-Cu/EP PCMs prepared by adding 3.47 wt% Cu is 148.5 J/g,which is 3.37 times higher than that of PEG/EP PCMs,reaching 0.463 W/(mK).Graphite was added to prepare EG-GP/EP PCMs in order to enhance the thermal conductivity by the same preparation process.The thermal conductivity of PEG-GP/EP PCMs with 1 wt% graphite addition reach 0.386 W/(mK),which is 3.15 times higher than that of PEG/EP PCMs.The compressive strength of fly ash thermal storage bricks reach the national standard MU15 while the PEG/EP doping content is less than 30 wt%.The compressive strength of the composite phase change material doped fly ash thermal storage bricks prepared by adding 30 wt% PEG-GP/EP PCMs meets the MU15 strength requirement after 28 days of curing,and the latent heats of the prepared fly ash thermal storage bricks reach 44.54 J/g,which indicate the thermal storage bricks have good thermal storage performance.