Study on the dynamic characteristics of a concentrated solar power plant with the supercritical CO2 Brayton cycle coupled with different thermal energy storage methods

Abstract

The paper aims to study the impact of Thermal Energy Storage (TES) technology on the dynamic characteristics of Concentrated Solar Power (CSP). An integrated dynamic model of a CSP plant is firstly established, which combines the concentrating system, the TES system, and S–CO2 Brayton power cycle system. Three TES alternatives are considered: two-tank molten salt TES (TT-TES), packed-bed TES with solid fillers (PBS-TES), packed-bed TES with phase change materials (PBP-TES). Using this integrated dynamic model, the thermal performance and economic feasibility of different TES technologies applied to CSP are compared and analyzed. The results indicate that utilization of packed-bed TES primarily impacts the optical efficiency of the heliostat field and the thermal efficiency of the power cycle, while having minimal effect on the receiver's thermal efficiency. Furthermore, during the vernal equinox, the daily average system efficiencies of CSP configurations integrating TT-TES, PBS-TES, PBP-TES technologies are 26.0 %, 25.5 %, and 24.5 %, respectively. Meanwhile, the use of packed-bed TES systems significantly reduces the material cost of the TES. In comparison to the TT-TES, the PBP-TES and the PBS-TES can reduce cost by 21.2 % and 42.3 %, respectively, and decrease TES volume by 83.0 % and 63.8 %, respectively.