Thermal storage materials mainly include phase change heat storage materials, thermal heat storage materials and so on. The latent heat storage technology of storing heat energy by using the solid-liquid or solid-solid phase variable latent heat of phase change materials has become the most practical development potential, the most widely used and the most important heat storage mode because of its advantages of large heat storage density, approximate isothermal heat storage process and easy control of process. Many substances have been studied as potential phase change heat storage materials (PCM), but only some of the substances have been industrially produced, of which the technology and products of refrigeration and low temperature range are relatively mature,
and many have been commercialized. France Cristopia, TEAP, Australia, Mitsubishi Chemistry, Japan (mitsubishichemical), Sweden Climator, Dow Chemical, United States, Rubitherm, Germany The types of PCM products produced by companies such as GmbH and MERCKKGAA are mainly salt solution, hydrated salt, paraffin and fatty acids, the melting point of which is-33~ 110 ℃. Typical organic phase change materials are paraffin, lipid acid, polymer compounds and so on. Thermal energy storage can store heat energy through the temperature change of matter, and the heat storage medium must have a large specific heat capacity. Solid substances that can be used as heat storage media include rocks, sand, metals, cement and bricks, and liquid substances, including water,
heat conduction oil, and melted salt. Compared with liquid heat storage materials, solid state heat storage materials have two characteristics: ① has a larger thermal energy storage temperature range, from room temperature to 1000 ℃ above the high temperature section, ② does not produce media leakage, the container material requirements are low. The main thermal storage materials studied in recent years are two alcohol two stearate (diol-di-stearates), sodium thiosulfate (Na2SO4·10H2O), polyethylene glycol 4, 42 benzyl methane diisocyanate/pentaerythritol copolymer (peg/mdi/pe copolymer), Aluminium magnesium Zinc Alloy (Al-34%Mg-6%Zn), high density polyethylene/paraffin mixture, etc.