Low pressure, modular compressed air energy storage (CAES) system for wind energy storage applications

The construction and testing of a modular, low pressure compressed air energy storage (CAES) system is presented. The low pressure assumption (5 bar max) facilitates the use of isentropic relations to describe the system behavior, and practically eliminates the need for heat removal considerations necessary in higher pressure systems to offset the temperature rise. The maximum overall system efficiency is around 97.6%, while the system physical footprint is less than 0.6 m3 (small storage room). This provides a great option for storage in remote locations that operate on wind energy to benefit from a nonconventional storage system. The overall size and capacity of the system can be changed by changing the number of active cylinders, which in this case are off-the-shelf, small pressure vessels used for fire protection. Moreover, the system operation is automated and capable of addressing both high energy and high power density applications with an infinite number of charge-discharge cycles by augmenting the capacity with the required number of storage cylinders. The system is eco-friendly and has low maintenance costs compared to chemical storage.