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.

A system for natural gas cooling using nitrogen. The system can include a nitrogen liquefier and a natural gas cooler. The nitrogen liquefier can provide liquid nitrogen to the natural gas cooler. One or more heat exchangers of the natural gas cooler can include a gaseous nitrogen output that is in fluid communication with the nitrogen liquefier. In response to receiving gaseous nitrogen at the nitrogen liquefier, from the one or more heat exchangers, a production rate of the the nitrogen liquefier is adjusted.

The present invention relates to cryogenic energy storage systems for storing using high-grade heat-of-compression. The system includes a liquefaction sub-system (100) and thermal energy storage device (300). The liquefaction sub-system (100) includes a first compressor (102), a first, second and third heat exchanger (104, 116, 112) and second compressor (114). The first and second heat exchangers (104, 116) are configured to transfer the high-grade heat of compression from the first and second compressors (102, 114) respectively to the thermal energy storage device (300). The third heat exchanger (112) is configured to recuperate the low-grade heat of compression from the second compressor (114) back into the second compressor (114) enabling the second compressor (114) to generate high-grade heat of compression. Further systems use compressors (124) and expanders (122). Further systems include power recovery sub-systems (400). The present disclosure also relates to methods of heat-of-compression storage in cryogenic energy storage systems.

A method for separating nitrogen from an inlet gas having less than 25 mole % nitrogen includes supplying the inlet gas having less than 25 mole % nitrogen to a nitrogen separation system configured with cryogenic refrigeration.

A system and method for the production and supply of a densified, liquid oxidant to a space vehicle launch facility is provided. A stream of liquid oxygen taken from a co-located, liquid producing air separation unit is densified in a two refrigeration stage, integrated densification system. The first refrigeration stage is a nitrogen based reverse Brayton cycle refrigeration cycle that provides refrigeration to the second refrigeration stage. The second refrigeration stage is a helium and/or neon comprising refrigerant loop that densifies the liquid oxygen to a temperature between about 70 Kelvin and 57 Kelvin. The integrated densification system may also be configured to densify liquid methane or other propellants used in space vehicle launches.

Cryogenic refrigeration device comprising a working circuit intended to cool a working fluid circulating in the said circuit, the working circuit comprising, arranged in series in a loop: a compression portion, a cooling portion, a portion with valve(s), an expansion portion and a reheating portion, in order to subject the working fluid to a recuperative working cycle comprising compression, then cooling, then expansion and then reheating to prepare for a new cycle, wherein the compression portion comprises at least one compressor having a linear piston driven by a linear motor, the expansion proportion comprises at least one expander with a linear piston, the portion with valve(s) comprises at least one regulating valve linearly actuated by a linear motor and controlled in order to supply or extract the working fluid from the at least one expansion piston.

An arrangement comprising at least one liquefaction plant for liquefying a gaseous medium to produce a liquefied medium; and at least one storage tank for storing the liquefied medium. A first transfer line is provided which is connected between the liquefaction plant and the storage tank, for transferring liquefied medium from the liquefaction plant into the storage tank. A second transfer line is connected between the liquefaction plant and the storage tank, for transferring gaseous medium from the storage tank into the liquefaction plant. The second transfer line, which used for transferring medium from the storage tank into the liquefaction plant, is arranged so that it is routed at least partially through the area of the storage tank in which the liquefied medium is stored in use.

An arrangement comprising at least one liquefaction plant for liquefying a gaseous medium to produce a liquefied medium; and at least one storage tank for storing the liquefied medium. At least one first transfer line is connected between the liquefaction plant and the storage tank, for transferring liquefied medium from the liquefaction plant into the storage tank. At least one second transfer line is connected between the liquefaction plant and the storage tank, for transferring gaseous medium from the storage tank into the liquefaction plant. At least one shut-off valve is provided in each transfer line. The apparatus further includes a bypass line

A heat exchanger 1 comprises a shell 2 which has in an interior thereof a heat exchange chamber 20 in which a gas to be cooled or an intermediate medium is filled, and performs heat exchange directly or indirectly between liquid hydrogen and the gas to be cooled, in the interior of the heat exchange chamber 20; a tray 23 which is provided in the interior of the heat exchange chamber 20 and receives a liquefied gas and a deposited substance F which are generated by the heat exchange in the interior of the heat exchange chamber 20; and a liquid discharge mechanism (flashboard 22, drain port 25, and drain pipe 26) which discharges the liquefied gas from the tray 23 in a state in which the deposited substance F is left in the tray 23.

A method for producing liquefied natural gas and a stream of liquid nitrogen including step a): producing gaseous nitrogen in an air separation unit; step b): liquefying a stream of natural gas in a natural gas liquefaction unit including a main heat exchanger and a system for producing cold; step c): liquefying the nitrogen stream resulting from step a) in the main exchanger of the natural gas liquefaction unit in parallel with the liquefied natural gas in step b); wherein all the cold necessary for liquefying the stream of nitrogen and for liquefying the natural gas is supplied by the system for producing cold of the natural gas liquefaction unit.