Patent ID: 8240146

Claim:
A method of substantially isothermal expansion and compression of a gas for energy storage and recovery to promote efficient use and conservation of energy resources, the method comprising: at least one of: (i) transferring a gas from a surrounding atmosphere into a pneumatic chamber of a cylinder assembly, the gas comprising atmospheric air, compressing the gas in the pneumatic chamber of the cylinder assembly, during the compression, thermally conditioning the gas by heat exchange with fluid from a heat transfer subsystem in fluid communication with the pneumatic chamber of the cylinder assembly, the heat transfer subsystem comprising a fluid source having a substantially constant temperature, and storing the compressed gas outside of the pneumatic chamber of the cylinder assembly; or (ii) transferring compressed gas from a vessel of compressed gas into the pneumatic chamber of the cylinder assembly, the gas comprising air, expanding the gas in the pneumatic chamber of the cylinder assembly, during the expansion, thermally conditioning the gas by heat exchange with fluid from a heat transfer subsystem in fluid communication with the pneumatic chamber of the cylinder assembly, the heat transfer subsystem comprising a fluid source having a substantially constant temperature, and venting the expanded gas into the surrounding atmosphere.