熔融盐单罐显热储热基本原理及自然对流传热规律

Sensible heat storage in a single tank using molten salt and associated natural convection heat transfer

熔融盐双罐显热储热技术已较为成熟,但储热成本较高。为了降低储热成本,本文提出在储热罐内布置浸没式换热器实现熔盐单罐储热和释热新方法,分析了熔融盐单罐储热基本原理,在此基础上模拟分析了垂直布置交错排列两根水平圆柱表面熔融盐自然对流传热的规律。研究发现,为了增强管排表面自然对流传热,两根圆柱的垂直间距不宜过小,而水平间距不宜过大,这些研究结果为熔融盐单罐储热设计提供理论基础。

Two-tank sensible heat storage using molten salt is a relatively mature technology. However, the cost for the storage method is high. A new single tank based storage method is proposed by using immersed heat exchangers for charging and discharging processes. Analyses are carried out on the newly proposed system. Further analyses are done on the natural convective heat transfer of molten salt around two vertically aligned horizontal cylinders. The results show that the natural convection heat transfer of molten salt around the array of cylinders can be enhanced if the vertical distance between the cylinders is not too small, whereas the horizontal distance between them is not too big. The results may serve as guidance for the design of single thermal energy storage tanks.