Preparation And Application Of Mica-based Composite Phase Change Materials For Thermal Energy Storage

Thermal energy storage technology with high energy storage density,cover an area of an area small and conversion efficiency higher advantages,has been used in the fields of solar thermal utilization,industrial waste heat recovery and building energy conservation.As the core of thermal energy storage technology,the high cost of thermal storage materials limits the industrialization promotion and application of thermal energy storage technology.Therefore,it is of great practical and engineering significance to develop low-cost and high-performance composite phase change materials for thermal energy storage.In this paper,mica with low prices and a wide range of sources are selected as the supporting matrix to reduce the production cost from the source.The mica-based composite phase change materials for thermal energy storage were prepared by loading polyethylene glycol.This work explores the mica potential applications in the field of thermal storage material.The application research of mica-based composite phase change materials for thermal energy storage was carried out.(1)The application potential of mica in the field of thermal storage materials was explored.Using five different mesh of mica as the supporting matrix,load polyethylene glycol,preparation a series of mica-based composite phase change materials for thermal energy storage.The microscopic morphology,crystal and chemical structure of the mica-based composite phase change materials for thermal energy storage were investigated,and it was confirmed that polyethylene glycol was successfully loaded into the lamellar structure of mica and showed good chemical compatibility.The thermal conductivity test showed that mica significantly improves the thermal conductivity and temperature change responsiveness of the phase change materials.Leakage tests confirmed that the lamellar structure of mica can effectively prevent the leakage of polyethylene glycol during phase transition.The above results confirm that mica as a support matrix has good application potential in the field of thermal storage materials.(2)The performance regulation mechanism of mica-based composite phase change materials for thermal energy storage was revealed.Decorated mica with silane coupling agent was used to prepare modified mica with larger specific surface area and pore volume,which provided favorable conditions for mica to adsorb more phase change materials.In order to further synergistically improve the thermal conductivity and thermal storage capacity of the mica-based composite phase change materials for thermal energy storage,a certain proportion of expanded graphite was added to the mica matrix to prepare the decorated mica/expanded graphite/polyethylene glycol composite phase change materials for thermal energy storage.The maximum load of mica-based composite phase change materials reaches 76.66%,and the melting latent heat of value reaches 136.3 J·g-1.The thermal conductivity is 0.56 W·m-1·K-1,which is 2.07 times that of pure polyethylene glycol.Through atomic structure simulation,the research on the synergistic improvement of thermal conductivity and thermal storage capacity by modified mica and the introduction of expanded graphite was carried out,and the performance regulation mechanism of mica-based composite phase change materials was revealed.(3)The application research of mica-based composite phase change materials for thermal energy storage has been carried out.The phase change cement mortar with thermal storage function was prepared by mixing the mica-based composite phase change materials for thermal energy storage with cement,and the application performance of the mica-based composite phase change materials in the field of building energy conservation was evaluated.The micabased composite phase change materials for thermal energy storage have great chemical stability with building materials.The chemical structure test showed that the mica-based composite phase change materials have great chemical compatibility with building materials.The application experiment of the building envelope showed that the phase change energy storage cement mortar can effectively slow down the heat loss and alleviate the indoor temperature fluctuation,thereby reducing the power consumption of the cooling and heating equipment in the building and realizing building energy conservation.In this paper,based on the unique morphological structure and thermal storage characteristics of mica,the mica-based composite phase change materials for thermal energy storage were prepared.The application potential of mica as a supporting matrix in the field of thermal storage materials was explored,the performance regulation mechanism of mica-based composite phase change materials was revealed,and the application research of mica-based composite phase change heat storage materials was carried out.It provides a new type of thermal storage material for thermal energy storage technology and enriches the theory of thermal storage.