A thermal storage subsystem may include at least a first storage reservoir disposed at least partially under ground 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 dispensing assembly for a pressure dispense package includes a connector having separate and distinct liquid and extraction conduits, and having a pressurization gas conduit. A liner fitment adapter may include a longitudinal bore to receive a probe portion of a connector defining a liquid extraction conduit, and may include a lateral bore to enable removal of gas. Insertion of a connector into a dispensing assembly simultaneously makes fluidic connections between (a) a gas extraction conduit and a dispensing volume; (b) a liquid extraction conduit and the dispensing volume, and (c) a pressurization gas conduit and a space to be pressurized within a pressure dispense vessel.

A system for producing and dispensing pressurized hydrogen includes: a hydrogen generator, in particular an electrolyser, a hydraulic drive, two or more hydrogen storage tanks, and a hydrogen dispensing unit, wherein each of the hydrogen storage tanks is capable of discharging hydrogen at a constant pressure by movement of an internal piston, wherein at least one of the hydrogen storage tanks is arranged to act as compressor by actuation of the internal piston by the hydraulic drive, and wherein at least one of the hydrogen storage tanks is arranged to act as a constant pressure tank for storing and discharging hydrogen at a constant pressure.

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 pressure tank includes a metallic vessel, a plastic liner received in the metallic vessel, a flexible diaphragm, two connectors and a nozzle coupled to the nipples respectively. The metallic vessel includes upper and lower shells. The upper shell defines a first planar area on a side thereof and a second planar area on a top thereof. The lower shell defines a third planar area thereunder. The flexible diaphragm divides the metallic vessel into a storage space and a pneumatic room. Each of the connectors includes a nipple and an anti-leak assembly. The nipples of the connectors are mounted on the side and top of the upper shell respectively and are in communication with the storage space. The two anti-leak assemblies provide leakproof connection between the nipples and the plastic liner. Additionally, the nozzle is mounted on the third planar area to be in communication with the pneumatic room.

A pressure vessel balanced refuelling system enables greater volumes of gas to be used as working volumes and increases gas storage efficiency. The system includes a plurality of pressure vessels, each vessel having a liquid transfer opening for the entry and exit of a liquid that is used to displace a gas inside each vessel. A liquid transfer line extends from an outside to an inside of each vessel in the plurality of pressure vessels through the liquid transfer opening, and a liquid balance line inter-connects the liquid transfer opening of each vessel with the liquid transfer opening of each other vessel. Thus a balance liquid transfer path extends from an inside to an outside of one vessel, then from the outside to the inside of each other vessel through the liquid balance line, enabling a liquid level in the one vessel to remain approximately equal to a liquid level in each other vessel.

A container may be supplied with an incompressible fluid. For example, the container may be partially or completely prefilled with the incompressible fluid. The container may be supplied with a flow of compressible gas via a first valve. The first valve may regulate the flow of the compressible gas supplied to the container based on a pressure setting of the first valve. A second valve may release the incompressible fluid from the container as the container is filled with the compressible gas and in response to a pressure of the container being greater than a pressure setting of the second valve. The pressure setting of the first valve may be greater than the pressure setting of the second valve.

A compressed gas energy storage system may include an accumulator for containing a layer of compressed gas atop a layer of liquid. A gas conduit may have an upper end in communication with a gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas into the compressed gas layer of the accumulator when in use. A shaft may have an interior for containing a quantity of a liquid and may be fluidly connectable to a liquid source/sink via a liquid supply conduit. A partition may cover may separate the accumulator interior from the shaft interior. An internal accumulator force may act on the inner surface of the partition and the liquid within the shaft may exert an external counter force on the outer surface of the partition, whereby a net force acting on the partition is less than the accumulator force.

A compressed gas energy storage system may include an accumulator for containing a layer of compressed gas atop a layer of liquid. A gas conduit may have an upper end in communication with a gas compressor/expander subsystem and a lower end in communication with accumulator interior for conveying compressed gas into the compressed gas layer of the accumulator when in use. A shaft may have an interior for containing a quantity of a liquid and may be fluidly connectable to a liquid source/sink via a liquid supply conduit. A partition may cover may separate the accumulator interior from the shaft interior. An internal accumulator force may act on the inner surface of the partition and the liquid within the shaft may exert an external counter force on the outer surface of the partition, whereby a net force acting on the partition is less than the accumulator force.

A system for storing and transporting compressed natural gas includes source and destination facilities and a vehicle, each of which includes pressure vessels. The pressure vessels and gas therein may be maintained in a cold state by a carbon-dioxide-based refrigeration unit. Hydraulic fluid (and/or nitrogen) ballast may be used to fill the pressure vessels as the pressure vessels are emptied so as to maintain the pressure vessels in a substantially isobaric state that reduces vessel fatigue and lengthens vessel life. The pressure vessels may be hybrid vessels with carbon fiber and fiber glass wrappings. Dip tubes may extend into the pressure vessels to selectively expel/inject gas from/into the top of the vessels or hydraulic fluid from/into the bottom of the vessels. Impingement deflectors are disposed adjacent to the dip tubes inside the vessels to discourage fluid-induced erosion of vessel walls.