Patent ID: 8037678

Claim:
A system for energy storage and recovery via expansion and compression of a gas, and that is suitable for the efficient use and conservation of energy resources, the system comprising: a first pneumatic cylinder assembly comprising (i) a first compartment, (ii) a second compartment, (iii) a piston, slidably disposed within the cylinder assembly, separating the compartments, and (iv) a piston rod coupled to the piston and extending outside the first compartment; a second pneumatic cylinder assembly comprising (i) a first compartment, (ii) a second compartment, (iii) a piston, slidably disposed within the cylinder assembly, separating the compartments, and (iv) a piston rod coupled to the piston and extending outside the first compartment; and a heat-transfer subsystem in fluid communication with at least one of the pneumatic cylinder assemblies, wherein (i) the piston rods of the first and second pneumatic cylinder assemblies are mechanically coupled, (ii) the first and second pneumatic cylinder assemblies are coupled in series pneumatically, thereby reducing a force range produced during expansion or compression of a gas within the first and second pneumatic cylinder assemblies, and (iii) the heat-transfer subsystem comprises a circulation apparatus for circulating a heat-transfer fluid through at least one compartment of at least one of the pneumatic cylinder assemblies.