A thermal storage subsystem may include at least a first storage reservoir configured to contain a thermal storage liquid at a storage pressure that is greater than atmospheric pressure. A liquid passage may have an inlet connectable to a thermal storage liquid source and configured to convey the thermal storage liquid to the liquid reservoir. A first heat exchanger may be provided in the liquid inlet passage and may be in fluid communication between the first compression stage and the accumulator, whereby thermal energy can be transferred from a compressed gas stream exiting a gas compressor/expander subsystem to the thermal storage liquid.

A thermal storage subsystem may include at least a first storage reservoir configured to contain a thermal storage liquid at a storage pressure that is greater than atmospheric pressure. A liquid passage may have an inlet connectable to a thermal storage liquid source and configured to convey the thermal storage liquid to the liquid reservoir. A first heat exchanger may be provided in the liquid inlet passage and may be in fluid communication between the first compression stage and the accumulator, whereby thermal energy can be transferred from a compressed gas stream exiting a gas compressor/expander subsystem to the thermal storage liquid.

An end cap holder may include a base block and a holding block. The base block may be configured to provide an end cap, which may be at a nozzle of the gas cylinder, with a torque for combining/separating the end cap with/from the nozzle. An angle correction groove may be formed at a first surface of the base block oriented toward the end cap. The holding block may be rotatably receivable in the angle correction groove to hold the end cap. The holding block may selectively make point contact with the base block to transmit the torque of the base block to the end cap. Thus, the holding block may accurately hold the end cap tilted to a vertical axis or a horizontal axis.

An end cap holder may include a base block and a holding block. The base block may be configured to provide an end cap, which may be at a nozzle of the gas cylinder, with a torque for combining/separating the end cap with/from the nozzle. An angle correction groove may be formed at a first surface of the base block oriented toward the end cap. The holding block may be rotatably receivable in the angle correction groove to hold the end cap. The holding block may selectively make point contact with the base block to transmit the torque of the base block to the end cap. Thus, the holding block may accurately hold the end cap tilted to a vertical axis or a horizontal axis.

An apparatus in the form of a subterranean storage container configured to store a volume of a small molecular gas, such as hydrogen or methane. In some embodiments, a casing is arranged to extend into a subterranean formation. A top end of the casing is connected to a top cap structure. The top cap structure includes an adapter flange connected to an inner liner which extends within the casing and is separated therefrom by a circumferentially extending annulus. The annulus is configured to be filled with a fluid at a predetermined pressure. The fluid may be an uncompressible liquid such as propylene glycol. The small molecular gas is stored within an interior of the inner liner at a selected pressure, such as above 1000 pounds per square inch (psi).

An apparatus in the form of a subterranean storage container configured to store a volume of a small molecular gas, such as hydrogen or methane. In some embodiments, a casing is arranged to extend into a subterranean formation. A top end of the casing is connected to a top cap structure. The top cap structure includes an adapter flange connected to an inner liner which extends within the casing and is separated therefrom by a circumferentially extending annulus. The annulus is configured to be filled with a fluid at a predetermined pressure. The fluid may be an uncompressible liquid such as propylene glycol. The small molecular gas is stored within an interior of the inner liner at a selected pressure, such as above 1000 pounds per square inch (psi).

An apparatus for fabricating an internally finned pressure vessel includes a plurality of positioning discs, each of the positioning discs defining a plurality of circumferentially spaced slots extending radially into the positioning disc from a perimeter thereof, and one or more rods extending through the plurality of positioning discs, the plurality of positioning discs being held in axial alignment by the one or more rods. A method of fabricating the internally finned pressure vessel includes providing the apparatus, loading a plurality of fins into the slots of the positioning discs, inserting the apparatus containing the plurality of fins into a pressure vessel, attaching the plurality of fins to the pressure vessel by a brazing process, and removing the apparatus from the pressure vessel.

An apparatus for fabricating an internally finned pressure vessel includes a plurality of positioning discs, each of the positioning discs defining a plurality of circumferentially spaced slots extending radially into the positioning disc from a perimeter thereof, and one or more rods extending through the plurality of positioning discs, the plurality of positioning discs being held in axial alignment by the one or more rods. A method of fabricating the internally finned pressure vessel includes providing the apparatus, loading a plurality of fins into the slots of the positioning discs, inserting the apparatus containing the plurality of fins into a pressure vessel, attaching the plurality of fins to the pressure vessel by a brazing process, and removing the apparatus from the pressure vessel.

An apparatus is provided for the storage and dispensing of a sorbable gas. The apparatus includes a storage and dispensing vessel constructed and arranged for containing a solid-phase physical sorbent medium having a sorbable gas adsorbed by said sorbent medium. The dispensing vessel includes a top head having a dispensing valve coupled to the vessel for discharging the sorbable gas therefrom. The dispensing valve is in fluid flow communication with a wick that extends below the upper third of the vessel top head. The wick collects the sorbable gas for discharge of the gas through the dispensing valve.

An apparatus is provided for the storage and dispensing of a sorbable gas. The apparatus includes a storage and dispensing vessel constructed and arranged for containing a solid-phase physical sorbent medium having a sorbable gas adsorbed by said sorbent medium. The dispensing vessel includes a top head having a dispensing valve coupled to the vessel for discharging the sorbable gas therefrom. The dispensing valve is in fluid flow communication with a wick that extends below the upper third of the vessel top head. The wick collects the sorbable gas for discharge of the gas through the dispensing valve.