Comprehensive assessment and optimization of a hybrid cogeneration system based on compressed air energy storage with high-temperature thermal energy storage

Abstract

Compressed air energy storage (CAES) is an effective technology for mitigating the fluctuations associated with renewable energy sources. In this work, a hybrid cogeneration energy system that integrates CAES with high-temperature thermal energy storage and a supercritical CO₂ Brayton cycle is proposed for enhancing the overall system performance. This proposal emphasizes system cost-effectiveness, eco-friendliness, and adaptability. Comprehensive analyses, including thermodynamic, exergoeconomic, economic, and sensitivity evaluations, are conducted to assess the viability of the system. The findings indicate that, under design conditions, the system achieves an energy storage density, a round-trip efficiency, an exergy efficiency, a unit product cost, and a dynamic payback period of 5.49 kWh/m³, 58.39%, 61.85%, 0.1421 $/kWh, and 4.81 years, respectively. The high-temperature thermal energy storage unit, intercoolers, and aftercooler show potential for optimization due to their suboptimal exergoeconomic performance. Sensitivity evaluation indicates that the operational effectiveness of the system is highly sensitive to the maximum and minimum air storage pressures, the outlet temperature of the high-temperature thermal energy storage unit, and the isentropic efficiencies of both compressors and turbines. Ultimately, the system is optimized for maximum exergy efficiency and minimum dynamic payback period. These findings demonstrate the significant potential of this system and provide valuable insights for its design and optimization.