6E analysis and particle swarm optimization of a novel ultra-high temperature solar cogeneration system fusing thermochemical energy storage and multistage direct heat transfer

• Direct-coupled solar cogeneration system without intermediate exchanger is proposed. • Carriers are simultaneously used for storage, power generation, and refrigeration. • 6E advanced analysis and particle swarm optimization of subsystems and subcomponents. • Seasonal economic benefits and regional operating characteristics are assessed. • Energy efficiency is increased by 1.31–8.2 % compared to similar solar cogeneration. The reshaping of the energy development model depends on the penetration of renewable energy on the input side and the substitution of electrical energy on the supply side. Therefore, this research proposes a novel solar cogeneration system in which the Brayton cycle possesses triple pressure and can be flexibly coupled directly to each subsystem under supercriticality without intermediate exchangers. Firstly, a series of research tasks are executed sequentially, including model establishment, cycle potential comparison, operating parameter analysis, and multi-objective particle swarm optimization. Secondly, the exergy flow rate, consumption rate, and 6E (energy, exergy, exergoeconomic, exergoenvironmental, emergoeconomic, and emergoenvironmental) performances of each subsystem and subcomponent are thoroughly discussed. Lastly, the operating performance, economic benefits, and regional characteristics of each subsystem and the cogeneration system are explored. After optimization, the exergy efficiency, average advanced exergy-emergy factor, and advanced exergy-emergy impact difference of the system are 22.72 %, 56.17 %, and 23.97 %. Compared with similar research, the energy efficiency of the system is improved by 8.2 %, which can repay the capital cost in 8.83 years, and the economic benefit reaches $5,503,086 for the entire service year. The system embodies excellent 6E performance, aligns with the goals of reshaping the energy development model, and provides guidelines for the development of ultra-high temperature solar cogeneration.