Abstract: Systems, methods and devices for optimizing heat transfer within a device or system used to compress and/or expand a gas, such as air, are described herein. For example, systems, methods and devices for optimizing the heat transfer within an air compression and expansion energy storage system are described herein. A compressor and/or expander device can include one or more of various embodiments of a heat transfer element that can be disposed within an interior of a cylinder or pressure vessel used in the compression and/or expansion of a gas, such as air. Such devices can include hydraulic and/or pneumatic actuators to move a fluid (e.g., liquid or gas) within the cylinder or pressure vessel. The heat transfer element can be used to remove heat energy generated during a compression and/or expansion process.

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.