Provided is a helium recondensation apparatus for a cryostat, which can stably recondense vapor of helium in the cryostat while preventing a pipeline for the recondensation from being clogged. A recondensation apparatus includes a freezer, a first heat exchanger, a first recondensing chamber, and a first connection part. The first heat exchanger stores heat-exchanging helium in a helium tank included in an NMR apparatus, and permits the heat-exchanging helium to evaporate owing to heat of vaporization taken from vapor of coolant helium in the helium tank, thereby permitting the coolant helium to recondense through heat exchange with the heat-exchanging helium. The first connection part is separated from the coolant helium in the helium tank and permits the heat-exchanging helium to flow between the first heat exchanger and the first recondensing chamber therethrough.

Provided is a helium recondensation apparatus for a cryostat, which can stably recondense vapor of helium in the cryostat while preventing a pipeline for the recondensation from being clogged. A recondensation apparatus includes a freezer, a first heat exchanger, a first recondensing chamber, and a first connection part. The first heat exchanger stores heat-exchanging helium in a helium tank included in an NMR apparatus, and permits the heat-exchanging helium to evaporate owing to heat of vaporization taken from vapor of coolant helium in the helium tank, thereby permitting the coolant helium to recondense through heat exchange with the heat-exchanging helium. The first connection part is separated from the coolant helium in the helium tank and permits the heat-exchanging helium to flow between the first heat exchanger and the first recondensing chamber therethrough.

An aircraft air conditioning system comprising an ambient air line, for ambient air to flow through, connected to supply ambient air to a mixer of the aircraft air conditioning system. An ambient air compressor is arranged in the ambient air line for compressing the ambient air flowing there through. A refrigerating apparatus comprises a refrigerant circuit for a refrigerant to flow through, including a refrigerant compressor arranged in the refrigerant circuit. The refrigerant circuit is coupled thermally to the ambient air line to transfer heat from the ambient air to the refrigerant before the ambient air is supplied to the mixer. A cabin exhaust air turbine is connected to a cabin exhaust air line, is coupled to the ambient air compressor arranged in the ambient air line, and is configured to expand the cabin exhaust air flowing through the cabin exhaust air line and to drive the ambient air compressor.

An aircraft air conditioning system comprising an ambient air line, for ambient air to flow through, connected to supply ambient air to a mixer of the aircraft air conditioning system. An ambient air compressor is arranged in the ambient air line for compressing the ambient air flowing there through. A refrigerating apparatus comprises a refrigerant circuit for a refrigerant to flow through, including a refrigerant compressor arranged in the refrigerant circuit. The refrigerant circuit is coupled thermally to the ambient air line to transfer heat from the ambient air to the refrigerant before the ambient air is supplied to the mixer. A cabin exhaust air turbine is connected to a cabin exhaust air line, is coupled to the ambient air compressor arranged in the ambient air line, and is configured to expand the cabin exhaust air flowing through the cabin exhaust air line and to drive the ambient air compressor.

A hydrogen cooling apparatus according to an embodiment includes: a binary refrigeration unit including a high-temperature-side refrigerator and a low-temperature-side refrigerator; and a hydrogen-cooling-fluid circulation unit. The binary refrigeration unit cools a hydrogen cooling fluid circulated by the hydrogen-cooling-fluid circulation unit by means of a low-temperature-side evaporator of the low-temperature-side refrigerator. The high-temperature-side refrigerator includes: a high-temperature-side refrigeration circuit; and a high-temperature-side bypass circuit including: a high-temperature-side bypass flow path that extends from a part, which is downstream of a high-temperature-side compressor and upstream of a high-temperature-side condenser in the high-temperature-side refrigeration circuit, to a part, which is downstream of a high-temperature-side expansion valve and upstream of a high-temperature-side evaporator in the high-temperature-side refrigeration circuit; and a high-temperature-side opening and closing valve provided on the high-temperature-side bypass flow path. The high-temperature-side refrigerator opens the high-temperature-side opening and closing valve when a high-temperature-side refrigerant has an abnormal pressure.

A hydrogen cooling apparatus according to an embodiment includes: a binary refrigeration unit including a high-temperature-side refrigerator and a low-temperature-side refrigerator; and a hydrogen-cooling-fluid circulation unit. The binary refrigeration unit cools a hydrogen cooling fluid circulated by the hydrogen-cooling-fluid circulation unit by means of a low-temperature-side evaporator of the low-temperature-side refrigerator. The high-temperature-side refrigerator includes: a high-temperature-side refrigeration circuit; and a high-temperature-side bypass circuit including: a high-temperature-side bypass flow path that extends from a part, which is downstream of a high-temperature-side compressor and upstream of a high-temperature-side condenser in the high-temperature-side refrigeration circuit, to a part, which is downstream of a high-temperature-side expansion valve and upstream of a high-temperature-side evaporator in the high-temperature-side refrigeration circuit; and a high-temperature-side opening and closing valve provided on the high-temperature-side bypass flow path. The high-temperature-side refrigerator opens the high-temperature-side opening and closing valve when a high-temperature-side refrigerant has an abnormal pressure.

A method for liquefying a feed gas stream. A compressed first refrigerant stream is cooled and expanded to produce an expanded first refrigerant stream. The feed gas stream is cooled to within a first temperature range by exchanging heat only with the expanded first refrigerant stream to form a liquefied feed gas stream and a warmed first refrigerant stream. A compressed second refrigerant stream is provided is cooled to produce a cooled second refrigerant stream. At least a portion of the cooled second refrigerant stream is further cooled by exchanging heat with the expanded first refrigerant stream, and then is expanded to form an expanded second refrigerant stream. The liquefied feed gas stream is cooled to within a second temperature range by exchanging heat with the expanded second refrigerant stream to form a sub-cooled LNG stream and a first warmed, second refrigerant stream.

A method for liquefying a feed gas stream. A compressed first refrigerant stream is cooled and expanded to produce an expanded first refrigerant stream. The feed gas stream is cooled to within a first temperature range by exchanging heat only with the expanded first refrigerant stream to form a liquefied feed gas stream and a warmed first refrigerant stream. A compressed second refrigerant stream is provided is cooled to produce a cooled second refrigerant stream. At least a portion of the cooled second refrigerant stream is further cooled by exchanging heat with the expanded first refrigerant stream, and then is expanded to form an expanded second refrigerant stream. The liquefied feed gas stream is cooled to within a second temperature range by exchanging heat with the expanded second refrigerant stream to form a sub-cooled LNG stream and a first warmed, second refrigerant stream.

A pulse tube cryocooler includes a pulse tube that includes a tube inner space, and an integral flow straightener that includes a flow straightening layer disposed to face the tube inner space so as to straighten a refrigerant gas flow from the tube inner space or into the tube inner space and a heat exchange layer formed integrally with the flow straightening layer outside the flow straightening layer with respect to the tube inner space so as to exchange heat with the refrigerant gas flow by contact with the refrigerant gas flow and is disposed at a low-temperature end and/or a high-temperature end of the pulse tube. The flow straightening layer includes a plurality of protrusions that protrude from the heat exchange layer toward the tube inner space.

A pulse tube cryocooler includes a pulse tube that includes a tube inner space, and an integral flow straightener that includes a flow straightening layer disposed to face the tube inner space so as to straighten a refrigerant gas flow from the tube inner space or into the tube inner space and a heat exchange layer formed integrally with the flow straightening layer outside the flow straightening layer with respect to the tube inner space so as to exchange heat with the refrigerant gas flow by contact with the refrigerant gas flow and is disposed at a low-temperature end and/or a high-temperature end of the pulse tube. The flow straightening layer includes a plurality of protrusions that protrude from the heat exchange layer toward the tube inner space.