Energy, exergy and economic (3E) analysis and multi-objective optimization of a combined cycle power system integrating compressed air energy storage and high-temperature thermal energy storage

Abstract

Traditional adiabatic compressed air energy storage system has a low turbine efficiency and a low power output due to the low turbine inlet temperature and high turbine outlet temperature without heat recovery. To address these issues, a combined cycle power system integrating compressed air energy storage and high-temperature thermal energy storage is proposed in this paper. The thermodynamic and economic models of the proposed system are developed considering the thermodynamic laws and life cycle assessment, respectively. The energy, exergy, economic (3E) analysis of the system are performed based on the models. The results show that under the design condition, the round-trip efficiency, exergy efficiency, energy storage density, levelized cost of energy and dynamic payback period of the system can reach 59.22 %, 62.12 %, 5.77 kWh/m3, 0.1186 $/kWh and 6.51 years, respectively. The sensitivity analysis shows that the maximum air storage pressure, minimum air storage pressure and outlet temperature of high temperature thermal energy storage system are the critical parameters impacting the system performance. Finally, the multi-objective optimization of the proposed system is carried out. The aforementioned three parameters are selected as the decision variables and the round-trip efficiency and levelized cost of energy are chosen as the objective functions. Compared with the pre-optimization system, the round-trip efficiency, exergy efficiency, and energy storage density of the system increase by 0.47 %, 0.43 %, and 1.33 kWh/m3, respectively, while the levelized cost of energy and dynamic payback period decrease by 0.0051 $/kWh and 1.55 years, respectively.