Systems and methods for optimizing thermal efficiency of a compressed air energy storage system

Abstract

Systems, methods and devices for optimizing thermal efficiency within a gas compression system are described herein. In some embodiments, a device can include a first hydraulic cylinder, a second hydraulic cylinder, and a hydraulic actuator. The first hydraulic cylinder has a first working piston disposed therein for reciprocating movement in the first hydraulic cylinder and which divides the first hydraulic cylinder into a first hydraulic chamber and a second hydraulic chamber. The second hydraulic cylinder has a second working piston disposed therein for reciprocating movement in the second hydraulic cylinder and which divides the second hydraulic cylinder into a third hydraulic chamber and a fourth hydraulic chamber. The hydraulic actuator can be coupled to the first or second working piston, and is operable to move the first and second working pistons in a first direction and a second direction such that volume in the hydraulic chambers are reduced accordingly.

1 .- 137 . (canceled) 
     
     
         138 . An apparatus suitable for use in a compressed gas-based energy storage and recovery system, the apparatus comprising:
 a first hydraulic cylinder comprising a first working piston disposed therein for reciprocating movement, the first working piston dividing the first hydraulic cylinder into, and defining therewith, a first hydraulic chamber and a second hydraulic chamber;   a second hydraulic cylinder comprising a second working piston disposed therein for reciprocating movement, the second working piston dividing the second hydraulic cylinder into, and defining therewith, a third hydraulic chamber and a fourth hydraulic chamber; and   an actuator coupled to and configured to move the first working piston and the second working piston:
 a) in a first direction such that liquid contained in the first hydraulic chamber and the third hydraulic chamber is discharged from the first hydraulic chamber and the third hydraulic chamber, and 
 b) in a second direction, opposite the first direction, such that liquid contained in the second hydraulic chamber and the fourth hydraulic chamber is discharged from the second hydraulic chamber and the fourth hydraulic chamber. 
   
     
     
         139 . The apparatus of  claim 138 , wherein a combined volume of the first and second hydraulic chambers is substantially equal to a combined volume of the third and fourth hydraulic chambers. 
     
     
         140 . The apparatus of  claim 138 , wherein a volume of the first hydraulic cylinder is not equal to a volume of the second hydraulic cylinder. 
     
     
         141 . The apparatus of  claim 138 , wherein a volume of the first hydraulic chamber is substantially equal to a volume of the third hydraulic chamber at any given time. 
     
     
         142 . The apparatus of  claim 138 , wherein a volume of the second hydraulic chamber is substantially equal to a volume of the fourth hydraulic chamber at any given time. 
     
     
         143 . The apparatus of  claim 138 , wherein a change in volume of the first hydraulic chamber corresponds to a change in volume of the second hydraulic chamber. 
     
     
         144 . The apparatus of  claim 138 , wherein a change in volume of the first hydraulic chamber corresponds to a change in volume of the third hydraulic chamber. 
     
     
         145 . The apparatus of  claim 138 , wherein the first and second hydraulic cylinders are fluidically coupled to a liquid storage structure. 
     
     
         146 . The apparatus of  claim 145 , wherein the liquid storage structure is at least one of a storage vessel, a pond, a tank, and a pool. 
     
     
         147 . The apparatus of  claim 138 , wherein the first hydraulic cylinder comprises a first fluid port and a second fluid port, the second hydraulic cylinder comprises a third fluid port and fourth fluid port, and
 wherein the actuator moving the first and second working pistons in the first direction causes:
 a) liquid contained within the first hydraulic chamber to be discharged from the first hydraulic chamber via the first fluid port, 
 b) liquid to be drawn into the second hydraulic chamber via the second fluid port, 
 c) liquid contained within the third hydraulic chamber to be discharged from the third hydraulic chamber via the third fluid port, and 
 d) liquid to be drawn into the fourth chamber via the fourth fluid port. 
   
     
     
         148 . The apparatus of  claim 138 , wherein the first hydraulic cylinder comprises a first fluid port and a second fluid port, the second hydraulic cylinder comprises a third fluid port and fourth fluid port, and
 wherein the actuator moving the first and second working pistons in the second direction causes:
 a) liquid to be drawn into the first hydraulic chamber via the first fluid port, 
 b) liquid contained within the second hydraulic chamber to be discharged from the second hydraulic chamber via the second fluid port, 
 c) liquid to be drawn into the third chamber via the third fluid port, and 
 d) liquid contained within the fourth hydraulic chamber to be discharged from the fourth hydraulic chamber via the fourth fluid port. 
   
     
     
         149 . The apparatus of  claim 138 , wherein the actuator is operable to move the first working piston in phase with the second working piston. 
     
     
         150 . The apparatus of  claim 138 , wherein the actuator is further configured to move the first and second working pistons:
 a) in the first direction to reduce the volume of the first hydraulic chamber and the third hydraulic chamber, and   b) in the second direction to reduce the volume of the second hydraulic chamber and the fourth hydraulic chamber.   
     
     
         151 . The apparatus of  claim 138 , wherein the actuator is selected from the group consisting of an electric motor and a hydraulic actuator. 
     
     
         152 . The apparatus of  claim 138 , wherein the apparatus comprises at least one additional hydraulic cylinder. 
     
     
         153 . A method of controlling thermal efficiency of a compressed gas-based energy storage and recovery system, the system comprising:
 a first hydraulic cylinder comprising a first working piston disposed therein for reciprocating movement, the first working piston dividing the first hydraulic cylinder into, and defining therewith, a first hydraulic chamber and a second hydraulic chamber;   a second hydraulic cylinder comprising a second working piston disposed therein for reciprocating movement, the second working piston dividing the second hydraulic cylinder into, and defining therewith, a third hydraulic chamber and a fourth hydraulic chamber; and   an actuator coupled to the first working piston and the second working piston, the method comprising:   moving, using the actuator, the first and second working pistons:
 a) in a first direction such that liquid contained in the first hydraulic chamber and the third hydraulic chamber is discharged from the first hydraulic chamber and the third hydraulic chamber, and 
 b) in a second direction, opposite the first direction, such that liquid contained in the second hydraulic chamber and the fourth hydraulic chamber is discharged from the second hydraulic chamber and the fourth hydraulic chamber. 
   
     
     
         154 . The method of  claim 153 , wherein the first hydraulic cylinder comprises a first fluid port and a second fluid port, the second hydraulic cylinder comprises a third fluid port and fourth fluid port, and wherein the method further comprises:
 a) discharging liquid contained within the first hydraulic chamber via the first fluid port,   b) drawing liquid into the second hydraulic chamber via the second fluid port,   c) discharging liquid contained within the third hydraulic chamber via the third fluid port, and   d) drawing liquid into the fourth chamber via the fourth fluid port.   
     
     
         155 . The method of  claim 153 , wherein the first hydraulic cylinder comprises a first fluid port and a second fluid port, the second hydraulic cylinder comprises a third fluid port and fourth fluid port, and wherein the method further comprises:
 a) drawing liquid into the first hydraulic chamber via the first fluid port,   b) discharging liquid contained within the second hydraulic chamber via the second fluid port,   c) drawing liquid into the third chamber via the third fluid port, and   d) discharging liquid contained within the fourth hydraulic chamber via the fourth fluid port.   
     
     
         156 . The method of  claim 153 , further comprising moving, using the actuator, the first working piston in phase with the second working piston. 
     
     
         157 . The apparatus of  claim 153 , further comprising moving, using the actuator, the first and second working pistons:
 a) in the first direction to reduce the volume of the first hydraulic chamber and the third hydraulic chamber, and   b) in the second direction to reduce the volume of the second hydraulic chamber and the fourth hydraulic chamber.   
     
     
         158 . The method of  claim 153 , further comprising fluidically coupling the first and second hydraulic cylinders to a liquid storage structure.