A modular subsea fluid storage unit comprises a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formations. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

A modular subsea fluid storage unit has a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formation. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

A modular subsea fluid storage unit has a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formations. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

Disclosed is a pneumatic membrane gasometer for the storage of hydrogen gas at low pressure. The gasometer includes: a first bag-shaped membrane delimiting a hydrogen storage chamber; a second membrane partially delimiting a pressurization chamber superimposed, at least in part, on the storage chamber; a third membrane, placed resting on top of the first membrane, fixed in an impermeable manner at least to the second membrane, defining, with the first membrane, a cavity open towards the outside of the gasometer; hydrogen supply and discharge unit associated with the storage chamber; pressurization unit; mechanical anchor to a base surface of the first, second and third membranes; and a natural passive ventilation system to vent any hydrogen losses to the outside, including a duct adapted to connect cavity to the outside environment passing through the pressurization chamber.

A modular subsea fluid storage unit comprises a variable-volume inner tank having a rigid top panel and a peripheral wall that is flexible by virtue of concertina formations. The peripheral wall is extensible and retractable vertically while the horizontal width of the tank remains substantially unchanged. A side wall of a lower housing part surrounds and is spaced horizontally from the peripheral wall of the inner tank to define a floodable gap between the peripheral wall and the side wall that surrounds the tank. An upper housing part extends over and is vertically spaced from the top panel of the inner tank and overlaps the side wall to enclose the inner tank. The floodable gap and the upper housing part enhance thermal insulation and trap any fluids that may leak from the inner tank.

In a cylindrically-formed gasholder sealing member interposed between an inner circumferential surface of a tank constituting a gasholder and an outer edge of a shock-absorbing member that rises and falls within the tank along with a movable piston that rises and falls within the tank at an outer circumferential side of the movable piston, both surfaces of at least a tank-ward end, out of a tank-ward end on a side anchored to the inner circumferential surface of the tank and a shock-absorbing member-ward end on a side anchored to the outer edge of the shock-absorbing member, are covered by ethylene propylene diene rubber, and a portion other than the tank-ward end and the shock-absorbing member-ward end is not covered by ethylene propylene diene rubber.

In a cylindrically-formed gasholder sealing member interposed between an inner circumferential surface of a tank constituting a gasholder and an outer edge of a shock-absorbing member that rises and falls within the tank along with a movable piston that rises and falls within the tank at an outer circumferential side of the movable piston, both surfaces of at least a tank-ward end, out of a tank-ward end on a side anchored to the inner circumferential surface of the tank and a shock-absorbing member-ward end on a side anchored to the outer edge of the shock-absorbing member, are covered by ethylene propylene diene rubber, and a portion other than the tank-ward end and the shock-absorbing member-ward end is not covered by ethylene propylene diene rubber.

In one aspect, a variable volume vessel includes an expandable/contractable bellows along with one or more components and/or features that prevent over-travel of the bellows and/or that prevent binding of the bellow relative to an outer housing of the vessel.

In one aspect, a variable volume vessel includes an expandable/contractable bellows along with one or more components and/or features that prevent over-travel of the bellows and/or that prevent binding of the bellow relative to an outer housing of the vessel.

Systems and techniques for compressed air energy storage and regeneration thereof are described herein. A compressor for compressed air energy storage and regeneration thereof can include a housing, a actuator, and a heat exchanger. The housing can define a volume. The actuator can be operable to expand the volume and compress the volume. The heat exchanger can be located at least partially within the housing. The heat exchanger can be configured to compress when the actuator compresses the volume, expand when the actuator expands the volume, and transfer heat with a working fluid.