Novel design optimization of concentrated solar power plant with S-CO2 Brayton cycle based on annual off-design performance

Abstract

• A novel design method of SPT plant with S-CO 2 Brayton cycle is proposed. • Design parameters of solar field, TES, and power cycle are optimized simultaneously. • Fluctuating weather conditions and power demands are introduced in real conditions. • Novel design method can improve the maximum load cover factor and reduce LCOE. • Two ways are found to improve load cover factor economically by adjusting parameters. This study proposes a novel design optimization method for the solar power tower (SPT) system with a supercritical CO 2 (S-CO 2 ) Brayton cycle. The design conditions are determined based on annual off-design performance. The fluctuating solar irradiation and ambient temperature in different locations, and various power demand scenarios, including stable, light industry, and hybrid PV + CSP system types, are considered. The parameters of solar multiple (SM), thermal energy storage (TES) capacity, and designed compressor inlet temperature are simultaneously optimized by the multi-objective optimization algorithm. Results show that compared with the conventional design method, the novel design method can improve the maximum load cover factor by 6.38% under stable power demand and reduce the levelized cost of energy by 5.62% with a load cover factor of 0.9 under light industry power demand in Daggett. The optimal design conditions and actual operating performance are significantly affected by the weather conditions, power demand scenarios, and optimization objectives. For most cases to increase load cover factor in the most economical way, increasing SM and TES capacity coordinately is preferred to be implemented first, followed by increasing designed compressor inlet temperature. Whereas, for cases with a high frequency of simultaneous high ambient temperature and high power demand, increasing designed compressor inlet temperature will be advanced to the same priority as increasing SM and TES capacity.