Analysis of a latent thermocline storage system with encapsulated phase change materials for concentrating solar power

Storing sun’s energy in the form of latent thermal energy of a phase change material (PCM) offers high volumetric energy storage density resulting in low capital cost. The objective of this paper is to analyze the dynamic behavior of a packed bed thermal energy storage system with encapsulated PCMs, subjected to partial charging and discharging cycles, and constraints on charge and discharge temperatures as encountered in a concentrating solar power (CSP) plant operation. A transient, numerical analysis of a molten salt, single tank latent thermocline energy storage system (LTES) is performed for repeated charging and discharging cycles to investigate its dynamic response. The influence of the design configuration and operating parameters on the dynamic storage and delivery performance of the system is studied to identify configurations that maximize utilization of the storage system. Based on the parametric studies, guidelines are derived for designing a packed bed PCM based storage system for CSP plant operating conditions.