Patent ID: 9109512
Filing Date: 2015-08-18
Classification: F02C,H02J,Y02E

Abstract:
1. A compressed gas-based energy storage and recovery system, comprising: a pneumatic cylinder having a working piston disposed therein for reciprocating movement in the pneumatic cylinder, the working piston dividing the pneumatic cylinder into, and defining therewith, a first pneumatic chamber and a second pneumatic chamber, the first pneumatic chamber having a first fluid port and a second fluid port, the first fluid port fluidically coupleable to a gas source, the second pneumatic chamber having a first fluid port and a second fluid port, the first fluid port fluidically coupleable to the gas source; a hydraulic actuator coupled to the working piston; a hydraulic controller fluidically coupleable to the hydraulic actuator, the hydraulic controller operable in a compression mode in which the hydraulic actuator causes gas to be discharged from the pneumatic cylinder at a higher pressure than it enters the pneumatic cylinder from the gas source, and an expansion mode in which gas in the pneumatic cylinder does work on the hydraulic actuator and is discharged from the pneumatic cylinder to the gas source at a lower pressure than it enters the pneumatic cylinder; and a compressed gas storage chamber including a first storage chamber and a second storage chamber, the first storage chamber fluidically coupleable to the second fluid port of the first pneumatic chamber and the second fluid port of the second pneumatic chamber, the first storage chamber comprising a subterranean storage chamber disposed at a first elevation and configured to contain a liquid and a gas in direct contact, the second storage chamber fluidically coupleable to the first storage chamber, the second storage chamber disposed at a second elevation greater than the first elevation, and configured to contain a volume of liquid, wherein operation of the hydraulic controller in the compression mode produces a first hydraulic actuator force on the working piston sufficient to move the working piston in a first direction such that a first mass of gas contained in the first pneumatic chamber is discharged from the first pneumatic chamber into the first storage chamber at a first pressure such that a first volume of liquid is displaced from the first storage chamber to the second storage chamber, and a second hydraulic actuator force on the working piston sufficient to move the working piston in a second direction, opposite the first direction, such that a second mass of gas contained in the second pneumatic chamber is discharged from the second pneumatic chamber into the first storage chamber at a second pressure greater than the first pressure such that a second volume of liquid is displaced from the first storage chamber to the second storage chamber, and wherein, when receiving gas in the first or second pneumatic chamber from the first storage chamber, a flow of liquid from the second storage chamber to the first storage chamber maintains gas in the first storage chamber at a pressure that is at least one of relatively constant and within a predetermined range.