熔融盐纳米复合材料混合蓄放热机理及调控机制

蓄能是太阳能高温热发电连续运行及风电、光伏发电规模接入的关键环节，熔融盐作为传热蓄热介质是人们的研究热点。高温熔融盐混合蓄放热机理及其调控机制对于高温单罐蓄热系统设计具有十分重要意义。为了降低蓄热成本，人们向熔融盐中添加纳米粒子，提高熔融盐导热系数和比热容，提高熔融盐传热蓄热特性。但现有的研究多集中在纳米粒子对熔融盐热物性影响研究，对于添加纳米粒子后熔融盐传热蓄热特性，尤其是单罐混合蓄放热机理影响报道较少。本研究以自主研发的低熔点四元混合硝酸盐为基体材料，探求稳定的高性能混合熔融盐纳米复合材料制备方法，探析纳米颗粒对混合熔融盐热物性提升机理，探究混合熔融盐纳米复合材料相变与自然对流传热规律及强化机理，获得混合熔融盐纳米复合材料混合蓄放热机理及调控机制，为熔融盐单罐蓄热系统设计提供理论设计依据及基础数据。

Thermal energy storage is a key process for the continuous operation of high temperature solar thermal power and for the large-scale grid-connection of renewable energy power. Molten salt, as a heat transfer and energy storage media, has become a key research area. Hybrid thermal charging and discharging mechanism and its regulation by high temperature molten salt is very important for the design of single thermal energy storage tank. In order to decrease the cost of thermal energy storage, some researchers added nanoparticles into molten salt to increase its thermal conductivity and specific heat capacity, so that the heat transfer and thermal energy storage performance can be enhanced. However, the most published research mainly focused on thermal properties enhancement of molten salt. Few studies were concentrated on the effect of nanoparticles on the heat transfer and energy storage performance, especially on the hybrid thermal charging and discharging mechanism. In this study, a quaternary nitrated salt with low melting point, developed by our group, has been selected as base materials to prepare molten salt nanocomposites. The study mainly focuses on the optimal preparation method of molten salt nanocomposites, on the thermal properties enhancement mechanism of molten salt nanocomposites, and on the phase change and natural convection heat transfer performance of molten salt nanocomposites. Based on the above researches, the hybrid thermal charging and discharging mechanism and its regulation can be got, which can provide a principle and basis data for the design of single thermal energy storage tank.