基于水合盐的低温热化学储能研究进展

The hydrated salt-based low temperature thermochemical energy storage has the advantages of high energy storage density and low heat loss in long-term storage. It has good application prospects in the fields of renewable energy utilization, low-grade waste heat recovery and equipment thermal management. In this paper, the research on hydrated salt-based thermochemical energy storage was reviewed from two aspects, including system level and material level. At the system level, the characteristics of open and closed reaction systems were compared. The advantages and disadvantages of common reactors and the optimization design were classified and discussed. The effects of material pile arrangement types on the heat storage process were discussed. In terms of material level, the thermochemical properties of materials such as single hydrated salts, mixed hydrated salts and porous support complex hydrated salts were evaluated. The macroscopic reaction kinetics and microscopic molecular dynamics models in the study of the thermochemical behavior of hydrated salts was introduced. The results show that mass transfer is the main factor limiting the reaction in an open system, and doubling the bed permeability can reduce the reaction time by about 50%. In a closed system, the main limitation of reaction is heat transfer, and doubling the thermal conductivity can reduce the reaction time by about 14%. Designing separated/ multi-module reactors, moving bed reactors and adopting the cascade layout of different thermochemical materials, the cascade layout of thermochemical materials and phase change materials, and the material bionic arrangement can effectively improve the uneven reaction of packed bed reactor. The mixed hydrated salts and porous support complex hydrated salts can solve the poor circulation stability of single hydrated salts. In the future, the study of reaction kinetic model and micro molecular dynamics are important research directions to understand the gas-solid reaction mechanism of hydrate salt.