Techno-economic analysis on the design of sensible and latent heat thermal energy storage systems for concentrated solar power plants

One feasible solution to reduce the cost of concentrated solar power is to employ a higher temperature and efficiency supercritical carbon dioxide Brayton power cycle. An alternative heat transfer medium and thermal energy storage (TES) system therefore needs to be explored. This work considered a variety of phase change materials (PCMs) and graphite as the storage media in four indirect shell-and-tube storage configurations, including a 3-PCM and 5-PCM cascade storage, a PCM-graphite-PCM hybrid storage and a single graphite storage. The sizing and design of the TES systems were performed by using a dynamic cycling methodology based on a transient 2D numerical model. The cost of those designs were then determined by using an economic model developed inhouse. This work also investigates the impact of some geometric parameters and cost assumptions on the techno-economic performance of the TES system. The analysis suggests a scenario exists whereby a low thermal efficiency storage system which therefore utilises less tube or storage material could be more cost-effective. Overall, the cost of hybrid TES is the lowest among all studied systems, at $26.96/kWh(t) and $21.49/kWh(t) for charging temperature of 720 degrees C and 750 degrees C, respectively, followed by the 5-PCM storage at $28.06/kWh(t) and $21.82/kWh(t), respectively. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study explored the design of thermal energy storage systems using various phase change materials and graphite as storage media, comparing their cost-effectiveness through an economic model. The analysis revealed that the hybrid TES system had the lowest cost among all systems studied.