Comprehensive Modeling and Energy-Exergy Analysis of Compressed Air Energy Storage Systems Based on Standard Thermal Resistance Method

ObjectivesIn order to effectively improve the energy storage characteristics and system efficiency of compressed air energy storage (CAES) systems, the performance of each component and their coupling characteristics are modeled and analyzed.MethodsIn this study, for CAES systems, the standard thermal resistance method is applied to take into account the transfer characteristics of the heat exchange components. Combined with the gas storage device and the work component model, this study establishes a comprehensive thermodynamic model integrating heat transfer, gas storage, and work coupling, along with an energy and exergy analysis model. The influence of the mass flow rate of energy storage and release on the system performance during compression and expansion is evaluated. The pattern of influence of the relationship between the maximum gas storage pressure and volume of the gas storage reservoir on the system energy storage efficiency and energy storage density is revealed.ResultsWith the increase of the mass flow rate of energy storage and release, the total energy consumption of the compressor first decreases and then increases, and the output work of the expander first increases and then decreases. When the mass rates of energy storage and release are 1.2 and 1.3, respectively, the system efficiency reaches the maximum value of 53.65%. In addition, the exergy loss of the first-stage compression and expander in the system is the largest, and the exergy loss of the oil-gas heat exchanger and the compressor accounts for 69% of the total exergy loss of the system.ConclusionsThe established model and the research findings provide important guidance for CAES operational strategy.