A new methodology for designing and assessing latent heat thermal energy storage systems

Abstract

This study established a methodology for designing a cascade latent heat thermal energy storage system. The latent heat thermal energy storage has been investigated by numerous researchers as an energy-dense and lower cost alternative to the two-tank molten salt sensible heat thermal energy storage for concentrated solar power plants. However, in order to achieve a high storage efficiency without decreasing the efficiency of the receiver and power block, many design restrictions should be applied in the design, including the total storage capacity, charging/discharging rate, charging/discharging period and the temperature difference of heat transfer fluid between the inlet and outlet of the storage system for both the charging and discharging process. There is no methodology or guideline currently available in the literature to design such a storage system. Therefore, a new methodology has been proposed, and it was successfully demonstrated in a case study. To achieve the final design, three major steps are involved: preliminary design, coarse optimization and fine optimization. Though intensive simulation is needed, the proposed methodology is appropriate to design the cascade latent heat thermal energy storage system.