A plant for energy storage, comprises: a basin (2) for a work fluid having a critical temperature (T.sub.c) lower than 0°; a tank (3) configured to store the work fluid in at least partly liquid or super-critical phase with a storage temperature (T.sub.s) close to the critical temperature (T.sub.c); an expander (4); a compressor (5); an operating/drive machine (6) operatively connected to the expander (4) and to the compressor (5); a thermal store (8) operatively interposed between the compressor (5) and the tank (3) and between the tank (3) and the expander (4). The plant (1) is configured for actuating a Cyclic Thermodynamic Transformation (TTC) with the work fluid, first in a storage configuration and then in a discharge configuration. The thermal store (8), in the storage configuration, is configured for absorbing sensible heat and subsequently latent heat from the work fluid and, in the discharge configuration, it is configured for transferring latent heat and subsequently sensible heat to the work fluid.

A method for operating a heat exchanger, in which a first operating mode is carried out in first time periods, and a second operating mode is carried out in second time periods that alternate with the first time periods; in the first operating mode a first fluid flow is formed at a first temperature, is fed into the heat exchanger in a first region at the first temperature, and is partially or completely cooled in the heat exchanger; in the first operating mode a second fluid flow is formed at a second temperature, is fed into the heat exchanger in a second region at the second temperature, and is partially or completely heated in the heat exchanger; and in the second operating mode the feeding of the first fluid flow and of the second fluid flow into the heat exchanger is partially or completely halted.

Disclosed techniques include gas liquefaction using hybrid processing. A gas is compressed adiabatically to produce a compressed gas at a first pressure. The compressing a gas adiabatically is accomplished using one or more compressing stages. Heat is extracted from the compressed gas at a first pressure. The heat that is extracted is collected in a thermal store. The compressed gas at a first pressure is further compressed. The further compressing is accomplished using a first liquid piston compressor. The further compressing produces a compressed gas at a second pressure. The first liquid piston compressor is cooled using a liquid spray. The compressed gas at a second pressure is cooled using a heat exchanger. The cooling accomplishes liquefaction of the compressed gas at a second pressure. The gas that was liquefied is stored for future use. The gas that was liquefied is used to perform work.

A method for operating the liquid air energy storage (LAES) includes production of the storable liquid air through consumption of a low-demand power and recovery the liquid air for co-production of an on-demand power and a high-grade saleable cold thermal energy which may be used, say, for liquefaction of the delivered natural gas; in so doing zero carbon footprint is provided both for fueled augmentation of the LAES power output and for LNG co-production at the LAES facility.

The present invention relates to a process and a system for supplying a backup gas at a higher pressure from a source gas at a lower pressure. The backup gas at the lower pressure is at least partially condensed against a backup liquid at a higher pressure in a reprocessing heat exchanger and as a result, the backup liquid is at least partially vaporized. The backup liquid at the higher pressure is formed from boosting liquefied backup gas at the lower pressure. A backup vaporizer is disposed downstream of the reprocessing heat exchanger to completely vaporize the backup liquid at a higher pressure before it was delivered to the customer. The present invention eliminates the use of costly gas compressor and mitigates associated safety risks, in particular when the backup gas is oxygen.

A novel concept for a high energy and material efficient nitric acid production process and system is provided, wherein the nitric acid production process and system, particularly integrated with an ammonia production process and system, is configured to recover a high amount of energy out of the ammonia that it is consuming, particularly in the form of electricity, while maintaining a high nitric acid recovery in the conversion of ammonia to nitric acid. The energy recovery and electricity generation process comprises pressurizing a liquid gas, such as air, oxygen and/or N.sub.2, subsequently evaporating and heating the pressurized liquid gas, particularly using low grade waste heat generated in the production of nitric acid and/or ammonia, and subsequently expanding the evaporated pressurized liquid gas over a turbine. In particular, the generated electricity is at least partially used to power an electrolyzer to generate the hydrogen needed for the production of ammonia. The novel concepts set out in the present application are particularly useful in the production of nitric acid based on renewable energy sources.

A mobile liquefaction plant (7) for liquefying helium, includes a liquefaction device (8) that liquefies helium, an intermediate storage tank (9) for liquefied helium, a cleaning device (29) which removes non-helium components from the helium and is connected upstream of the liquefaction device, and an additional collecting device (25) that collects gaseous helium which evaporates when an application cryostat (4) is filled with liquid helium and that includes a container (26) with a flexible wall and which stores the collected gaseous helium approximately at atmospheric pressure. The container (26) has an available container volume of at least 5 m.sup.3. Systems provided with such a mobile liquefaction plant exhibit an improved recovery of helium from application cryostats in a simple and cost-effective manner.

Disclosed techniques include controlled liquefaction and energy management. A gas within a first pressure containment vessel is pressurized using a column of liquid. The gas that is being pressurized is cooled using a liquid spray, wherein the liquid spray is introduced into the first pressure containment vessel in a region occupied by the gas. The liquid spray keeps the pressurizing to be isothermal. The gas that was pressurized is metered into a second pressure containment vessel, wherein the metering enables liquefaction of the gas. The gas that was pressurized is stored in a gas capacitor prior to the metering. The gas that was liquefied in the second pressure containment vessel is pushed into a holding tank, wherein the holding tank stores a liquefied state of the gas, and wherein the pushing is accomplished by the pressure of the gas that was metered into the second pressure containment vessel.

A system which integrates a power production system and an energy storage system represented by gas liquefaction systems is provided.

A proposed method provides a fueled power output augmentation of the liquid air energy storage (LAES) with zero carbon emissions of its exhaust. It combines the production of liquid air using a low-demand power from the renewable or/and conventional energy sources and the recovery of stored air for production of on-demand power in the fueled supercharged reciprocating internal combustion engine (RICE) and associated expanders. An integration between the LAES and RICE makes possible to recover the RICE exhaust energy for increase in power produced by the expanders of LAES and to use a cold thermal energy of liquid air being re-gasified at the LAES facility for cryogenic capture of CO.sub.2 emissions from the RICE exhaust.