关键词: 相变材料, 储能技术, 封装技术, 微胶囊, 多孔介质, 复合材料

Abstract:

Phase change materials (PCMs) can release and absorb latent energy through the phase change process, which has many applications in the field of temperature control and heat storage such as building energy conservation, solar energy storage, textile and other daily aspects. Most PCMs have problems of low thermal conductivity and leakage, and thus encapsulation is necessary for shape-stable and heat transfer enhancement. At present, microencapsulation and porous encapsulation are commonly used due to microencapsulation can build a relatively isolated system to prevent leakage and has a large specific surface area. And encapsulation by porous support has high energy storage density and utilization efficiency. This paper reviewed the structural characteristics and applicable types of the two methods, introduced the specific preparation methods and research progress of the encapsulation technologies such as spray drying, in-situ polymerization, complex coacervation, sol-gel, direct impregnation, vacuum adsorption and in-situ assembly. Besides, the paper briefly described the characteristics and progress of nanofiber encapsulation and solid-solid PCMs encapsulation. Finally, the evaluation contents and methods of shape stabilized phase change energy storage materials (SSPCMs) were summarized. Different methods had advantages and disadvantages in reducing leakage rate, increasing stability and improving thermal conductivity and storage efficiency. The shape-stable improvement and enhanced heat transfer are still the development focus of future PCMs encapsulation. The cost economy, simple process, high energy storage density, suitable phase change temperature and environmentally friendly PCMs would have greater application prospects.

Key words: phase change materials, energy storage technology, encapsulation technology, microencapsulation, porous support, composites