How does a compressed air energy storage system work?

The performance of compressed air energy storage systems is centred round the efficiency of the compressors and expanders. It is also important to determine the losses in the system as energy transfer occurs on these components. There are several compression and expansion stages: from the charging, to the discharging phases of the storage system.

Why is water injected into compressed air energy storage systems?

The presence of water in compressed air energy storage systems improves the efficiency of the system, hence the reason for water vapour being injected into the system [, ]. This water vapour undergoes condensation during cooling in the heat exchangers or the thermal energy system [, ].

What is compressed air energy storage (CAES)?

S. Hari Charan Cherukuri, in Journal of Energy Storage, 2021 Compressed Air Energy Storage (CAES) is an option in which the pressure energy is stored by compressing a gas, generally air, into a high pressure reservoir. The compressed air is expanded into a turbine to derive mechanical energy and hence run an electrical generator.

How is compressed air stored?

The compressed air is then stored in a dedicated pressurized reservoir, which can be either an underground cavern or an aboveground tank, typically maintained at a pressure of 40-80 bar. During the discharge phase, the elastic potential energy stored in the compressed air is harnessed.

What determines the design of a compressed air energy storage system?

The reverse operation of both components to each other determines their design when integrated on a compressed air energy storage system. The screw and scroll are two examples of expanders, classified under reciprocating and rotary types.

How electrical energy can be stored as exergy of compressed air?

(1) explains how electrical energy can be stored as exergy of compressed air in an idealized reversed process. The Adiabatic method achieves a much higher efficiency level of up to 70%. In the adiabatic storage method, the heat, which is produced by compression, is kept and returned into the air, as it is expanded to generate power.