Underwater compressed air energy (UW-CAES) systems own plentiful merits of high system efficiency, high energy density and stable operation. In terms of research gap of its coupling properties of thermodynamics and economics, along with research lack focusing on detailed design parameters, the comprehensive thermodynamic and economic coupling model of UW-CAES systems are developed in this paper, specifically including more details of heat exchanger structure, thermal storage medium and an improved energy density. In addition, the discharging power capacity is maintained constant in the analysis for practical design. Then, the effect of key parameters on the whole system's thermodynamic and economic performance is deeply investigated in which the coupling characteristics among parameters are focused on. Results show that the studied UW-CAES system has a good thermodynamic performance with a high system efficiency of 0.7074 and an enhanced high energy density of 26.07 MJ/ m³ considering thermal storage tanks. The system investment can be achieved as low as $3.983 million when water is thermal storage medium. Sensitive analysis shows that it is beneficial to improve the whole system performance with larger underwater pipe diameter, and the discharging pressure should not be lower than 30 bar to avoid efficiency and economic deteriorating. The growing discharging power will increase system investment, while decreasing levelized cost of electricity (LCOE) significantly. Generally, the economy of UW-CAES systems with thermal oil is much worse than counterparts with water. As the thermal storage medium is water, there exist optimum economic ranges of discharging pressure, NTU, length-width ratio and part number.

水下压缩空气能（UW-CAES）系统具有系统效率高、能量密度高、运行稳定等诸多优点。针对UW-CAES系统热力学和经济耦合特性的研究空白，缺乏对详细设计参数的研究，本文建立了UW-CAES系统的综合热力学和经济耦合模型，具体包括更多的换热器结构细节。 、蓄热介质和改进的能量密度。此外，在实际设计的分析中，放电功率容量保持恒定。然后，深入研究了关键参数对整个系统热力学和经济性能的影响，重点研究了参数之间的耦合特性。³考虑储热罐。当水为蓄热介质时，系统投资可低至398.3万美元。敏感分析表明，水下管径较大有利于提高整个系统性能，排放压力不应低于30 bar，以免降低效率和经济性。不断增长的放电功率将增加系统投资，同时显着降低电力平准化成本（LCOE）。通常，使用导热油的 UW-CAES 系统的经济性比使用水的系统差得多。由于蓄热介质为水，因此排放压力、NTU、长宽比和零件数存在最佳经济范围。