Research on Operation Strategy of Compressed Air Energy Storage System during Compression Phase

With the increasing proportion of intermittent renewable energy sources such as wind and solar energy in the power grid, the importance of energy storage technology in ensuring stable operation of the grid has become increasingly prominent. Compressed Air Energy Storage (CAES) technology, with its advantages of large scale, long lifespan, and relatively low cost, is considered to be a highly promising large-scale energy storage method. This paper focuses on two typical operation strategies for the compression phase of CAES systems: constant pressure operation and sliding pressure operation. By establishing a system thermodynamic and off-design mathematical model that includes multi-stage compressors, inter-stage coolers, and gas storage devices, the dynamic operation characteristics under the two strategies are simulated and compared in detail. The results show that constant pressure operation enables the compressors at all stages to operate under stable conditions, with simple system control but throttling losses; sliding pressure operation avoids throttling losses, but as the pressure in the gas storage chamber increases, the reduced flow rate, pressure ratio, adiabatic efficiency, output power, and outlet temperature of the compressors at all stages all exhibit significant dynamic evolution processes, with particularly drastic changes in the parameters of the last-stage compressor, ultimately tending towards consistency at the end of the compression phase. This study reveals the inherent mechanisms and performance differences between the two operation strategies, providing a theoretical basis for the optimal design and operation strategy selection of the compression phase of CAES systems.