Objective Addressing the challenges of integrating a high proportion of renewable energy and supporting the "dual carbon" goals necessitates the development of efficient, large-scale, long-duration energy storage technologies. To address the issues of limited heat generation and underutilized heating potential in artificial cavern-based adiabatic compressed air energy storage (CAES) systems, this study proposes a multi-heat-source utilization method, aiming to optimize the heat source, enhance system performance, and provide theoretical support for engineering applications.

Method A technical approach involving heat source screening, system modeling, and characteristic analysis was adopted. Potential multiple heat sources were evaluated based on heat source quality, geographical adaptability, and synergistic potential. Solar thermal energy was identified as the optimal choice. Consequently, a thermodynamic model for a solar thermal-coupled CAES system was established. The influence of key parameters was investigated through parametric sensitivity analysis.

Result The results show that when the molten salt temperature increases from 300 ℃ to 600 ℃, the system round-trip efficiency rises from 54.70% to 69.79%, and the annual carbon emission reduction benefit increases from 3.76 million CNY to 9.16 million CNY. When the compressor efficiency is improved from 80% to 90%, the round-trip efficiency increases from 63.52% to 68.05%, while when the turbine efficiency is increased from 80% to 94%, it increases from 59.10% to 67.92%. An increase in the heat exchanger terminal temperature difference during discharge from 10 ℃ to 100 ℃ leads to a 4 percentage point decrease in round-trip efficiency, and raising the heat exchanger pressure loss from 0 to 0.1 MPa results in a 5 percentage point drop. The system levelized cost of electricity ranges from 0.45 to 0.54 CNY/kWh, demonstrating certain techno-economic advantages.

Conclusion System performance is highly sensitive to key parameters such as molten salt temperature, compressor and turbine efficiencies, and heat exchanger characteristics. This study reveals the influence patterns of core parameters on system performance, provides an important theoretical basis for the engineering application of this system, and contributes to the advancement of large-scale long-duration energy storage technologies.