Abstract: 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.

Key words: molten salt, sensible heat, heat storage, natural convection