Abstract: In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.

Abstract: In various embodiments, systems for providing a constant electrical output from a compressed gas energy storage and recovery system include a hydraulic-pneumatic energy storage and recovery system configured to provide a varying pressure profile at least at one outlet, a hydraulic motor-pump in fluid communication with the outlet, and a control system for enabling the constant electrical output by controlling at least one of pressure, piston position, power, flow rate, torque, RPM, current, voltage, frequency, or displacement per revolution.

Abstract: The invention relates to systems and methods including an energy conversion system for storage and recovery of energy using compressed gas, a source of recovered thermal energy, and a heat-exchange subsystem in fluid communication with the energy conversion system and the source of recovered thermal energy.

Abstract: The invention relates to systems and methods for rapidly and isothermally expanding and compressing gas in energy storage and recovery systems that use open-air hydraulic-pneumatic cylinder assemblies, such as an accumulator and an intensifier in communication with a high-pressure gas storage reservoir on a gas-side of the circuits and a combination fluid motor/pump, coupled to a combination electric generator/motor on the fluid side of the circuits. The systems use heat transfer subsystems in communication with at least one of the cylinder assemblies or reservoir to thermally condition the gas being expanded or compressed.

Abstract: The invention relates to methods and systems for the storage and recovery of energy using open-air hydraulic-pneumatic accumulator and intensifier arrangements that combine at least one accumulator and at least one intensifier in communication with a high-pressure gas storage reservoir on a gas-side of the circuits and a combination fluid motor/pump, coupled to a combination electric generator/motor on the fluid side of the circuits.

Abstract: In various embodiments, energy is stored or recovered via super-atmospheric compression and/or expansion of gas in conjunction with substantially adiabatic compression and/or expansion from or to atmospheric pressure.

Abstract: In various embodiments, dead space and associated coupling losses are reduced in energy storage and recovery systems employing compressed air via use of a compressed-gas reservoir for maintaining a connector between cylinder assemblies at an intermediate pressure, thereby reducing the volume of dead space in the connector and increasing efficiency of the energy storage and recovery.

Abstract: In various embodiments, cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the cylinder assemblies during expansion or compression of a gas.

Abstract: In various embodiments, efficiency of energy storage and recovery systems employing compressed air and liquid heat exchange is improved via control of the system operation and/or the properties of the heat-exchange liquid.

Abstract: In various embodiments, compressed-gas energy storage and recovery systems feature one or more valves, which may be disposed within end caps of cylinder assemblies in which gas is expanded and/or compressed, for admitting fluid to and/or exhausting fluid from the cylinder assembly.

Abstract: In various embodiments, energy storage and recovery features energy conversion to and from gravitational potential energy.

Abstract: The invention relates to systems and methods including an energy conversion system for storage and recovery of energy using compressed gas, a source of recovered thermal energy, and a heat-exchange subsystem in fluid communication with the energy conversion system and the source of recovered thermal energy.

Abstract: In various embodiments, a pneumatic cylinder assembly is coupled to a mechanism that converts motion of a piston into electricity, and vice versa, during expansion or compression of a gas in the pneumatic cylinder assembly.

Abstract: In various embodiments, heat is exchanged with a gas being compressed or expanded within an energy storage and recovery system without the use of flexible hoses.

Abstract: In various embodiments, pneumatic cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the pneumatic cylinder assemblies during expansion or compression of a gas.

Abstract: In various embodiments, energy is stored or recovered via super-atmospheric compression and/or expansion of gas in conjunction with substantially adiabatic compression and/or expansion from or to atmospheric pressure.

Abstract: In various embodiments, motor-pump efficiency is increased by limiting the fluid pressure communicated to the motor-pump to a range smaller than that communicated by other components of an energy storage and/or recovery system.

Abstract: In various embodiments, dead space and associated coupling losses are reduced in energy storage and recovery systems employing compressed air.

Abstract: In various embodiments, gas is compressed to store energy and/or expanded to recover energy to or from high pressures, and the gas is exchanges heat with a heat-exchange fluid that is thermally conditioned at low pressures.

Abstract: In various embodiments, efficiency of energy storage and recovery systems compressing and expanding gas is improved via heat exchange between the gas and a heat-transfer fluid.