Patent ID: 8146354

Claim:
A method comprising: introducing a first quantity of air at a first temperature into a first chamber; in a compression cycle, subjecting the first quantity of air to compression by a first moveable element coupled to a mechanical linkage and moveable within the first chamber; injecting a first determined quantity of liquid into the first quantity of air to absorb thermal energy generated by the compression cycle and thereby maintain the first quantity of air in a first temperature range during the compression; transferring at least a portion of the first quantity of air from the first chamber to a first gas-liquid separator; in an expansion cycle, transferring a second quantity of air to the first chamber; allowing the second quantity of air to expand and drive the first moveable element and the mechanical linkage; injecting a second determined quantity of a liquid into the second quantity of air to provide thermal energy absorbed by the expanding air and thereby maintain the second quantity of air in a second temperature range during the expansion, wherein the second determined quantity of liquid is flowed from the first gas-liquid separator; providing a valve allowing selective fluid communication between the first chamber and a next lowest pressure stage or ambient pressure; and controlling a valve timing to transfer a third quantity of air expanded in the first chamber through a second gas-liquid separator to the next lowest pressure stage or to ambient.