Abstract: A refrigerator control method is disclosed which ensures efficient operation of a compressor. To control a refrigerator including a compressor, a first evaporator and a second evaporator connected to the compressor, and a refrigerant control valve that controls introduction of a refrigerant into the first evaporator and the second evaporator, the refrigerator control method includes operating the compressor, and controlling the opening and closing of the refrigerant control valve, to reduce not only consumption of electricity by the compressor, but also a pressure difference between an entrance and an exit of the compressor upon starting of the compressor.

Abstract: In a cooling system, a compressor (1), a heat source (2), a heat exchanger (3), and a buffer tank (4) are connected in that order by piping (5) to constitute a closed circuit. In the closed circuit, nitrogen serving as a refrigerant is circulated without contacting open air. Any gas except for the air may be used as the refrigerant as long as the gas absorbs heat from the heat source (2) and dissipates the heat to the outside in the heat exchanger (3) when the gas is circulated in the closed circuit without being liquefied.

Abstract: A refrigerant leak-detection system is provided to monitor a level of refrigerant/refrigerant by-products in ambient air in a closed/semi-closed ventilated environment enclosing a refrigeration unit. The system comprises a sensor positioned in the ventilated environment to measure a level of refrigerant/refrigerant by-products in the ambient air, and a detection controller to receive signals associated with the level of refrigerant/refrigerant by-products in the ambient air and to perform an action as a function of the signals. The detection controller stops a ventilation unit for given periods of time to allow the sensor to measure the level of refrigerant/refrigerant by-products in the ambient air during the given periods of time. A method for monitoring the level of refrigerant/refrigerant by-products in ambient air in a closed/semi-closed ventilated environment enclosing a refrigeration unit is also provided.

Abstract: Apparatus for detecting the escape of a fluid from a cooling system having a passage (1, 2, 3), comprises: a housing (4, 5) defining a volume abutting one or more portions of said passage; and sensor means (6, 7) adapted to detect the presence of said fluid within said volume; and wherein the housing is adapted to collect the escaped fluid such that the sensor can detect the escaped fluid before the operation of the cooling system is compromised. The passage of the cooling system may be a pipe of a heat exchange circuit, and the fluid may be a heat transfer fluid such as carbon dioxide. The apparatus may be adapted to signal to alarm means or other monitoring systems on detection of escaped fluid.

Abstract: A system and method for monitoring an overheat condition of a compressor is provided. A compressor connected to an evaporator. A suction sensor outputs a suction signal corresponding to a temperature of refrigerant entering the compressor. A control module is connected to the evaporator sensor and the suction sensor and determines an evaporator temperature, calculates a suction superheat temperature based on the evaporator temperature and the suction signal, and monitors an overheat condition of the compressor by comparing the suction superheat with a predetermined suction superheat threshold.

Abstract: A system, compressor, and method that cools an electronics module with a low-pressure refrigerant. The system, compressor, and method utilize a temperature sensor that detects a temperature of the low pressure refrigerant and communicates with the electronics module. Based on the temperature detected by the temperature sensor, the electronics module controls a liquid dry out point of the refrigerant that is used to cool the electronics module.

Abstract: A system includes a compressor temperature sensor that generates a compressor discharge temperature signal corresponding to a compressor of a refrigeration system, a compressor pressure sensor that generates a compressor discharge pressure signal corresponding to the compressor, and a controller processing the signals over a predetermined time period. The processing includes calculating a discharge saturation temperature based on the compressor discharge pressure signal, calculating compressor superheat data based on the compressor discharge temperature signal and the discharge saturation temperature, accumulating the compressor superheat data over the predetermined time period, and comparing the accumulated compressor superheat data to a predetermined threshold. The controller generates an alarm indicating a compressor fault based on the comparing.

Abstract: The present invention discloses an apparatus and method for supercooling which can stably maintain the contents in a supercooled state for an extended period of time by controlling energy. The apparatus for supercooling includes a means for taking energy from the contents, and a means for causing at least one of rotation, vibration and translation to water molecules of the contents, by supplying energy smaller than the taken energy. The contents arc maintained in a liquid state below a phase transition temperature.

Abstract: A beverage cooling element includes a housing having a main body portion and a stem portion, both filled with a freezable material. The stem portion is removably held in a hollow bore of a stem of a drinking vessel, especially a martini glass, containing a liquid beverage, and the main body portion is held in direct contact with the beverage to effect a rapid, direct heat transfer between the frozen material and the beverage to be cooled.

Abstract: A display case for storing food and beverage products that evenly distributes chilled air within the display case that includes a cassette unit and a chassis that has an interior volume that is encapsulated by a front section, a rear section, a base portion and a top portion and two side portions. The chassis has one or more shelves and one or more goal posts mounted therein. The goal posts deliver chilled air to the shelves. The shelves have a bottom surface that has a plurality of impingement holes disposed therein that disperse the chilled air into the interior volume so that the chilled air blankets the top of the food and beverage products on the shelves below. The shelves may incorporate a groove in the bottom surface. Low power consumption LED lighting may be incorporated in the grove to illuminate the product on the shelf below.

Abstract: Refrigeration circuit comprising a compressor, a heat-rejecting heat exchanger an expansion valve, a receiver (3), and a further expansion valve/evaporator to provide cooling. A second heat exchanger (24) is arranged in an upper gas portion of the receiver and/or a third heat exchanger (34) is arranged in a lower liquid portion of the receiver. A better liquid/vapour separation of the refrigerant and/or sub-cooling of the liquid refrigerant are achieved.

Abstract: The present invention provides an air conditioner for a vehicle that includes a closed refrigeration loop. The closed refrigeration loop includes a compressor, a refrigerant-to-coolant heat exchanger, a coolant-to-refrigerant heat exchanger and a refrigerant dryer in series fluid connection with one another. An engine coolant outlet connector is connected to the coolant-to-refrigerant exchanger. A compartment inlet connector connected to the coolant-to-refrigerant heat exchanger. A compartment outlet connector connected to the refrigerant-to-coolant heat exchanger. An engine coolant inlet connector connected to the refrigerant-to-coolant heat exchanger.

Abstract: A scroll compressor system having a variable speed drive is utilized. By providing the economizer and/or bypass functions along with the variable speed drive, precise capacity adjustment between the discrete steps is achieved to exactly match load demands at a wide spectrum of operating conditions.

Abstract: The invention relates to a refrigeration circuit having a mono- or multi-component refrigerant circulating therein, said refrigeration circuit comprising at least one expansion device. According to the invention, the expansion device is provided in the form of at least two valves (a, b, c, d) connected in parallel. Furthermore, the invention relates to a method of operating such a refrigeration circuit. Said method is characterized in that, in case of a defect of one of the valves (a, b, c, d) connected in parallel, said defective valve is taken out of operation and the or at least one of the additional valves ensures the control operation of the refrigeration circuit.

Abstract: The present invention relates to a refrigerant circuit (1), in particular for use in a liquefaction plant, the refrigerant circuit (1) at least comprising: —a refrigerator (2) having an inlet (21) for refrigerant (10) at a refrigeration pressure, and at least five outlets (22, 23, 24, 25, 26, . . . ) for evaporated refrigerant (20, 30, 40, 50, 60, . . . ) evaporated at different pressure levels, the at least five outlets (22, 23, 24, 25, 26, . . . ) being preferably intended for refrigerants evaporated at increasing pressures from the first outlet (22) to the fifth (26) and optional higher outlets; —a first compressor (3) having one or more inlets for receiving evaporated refrigerant from the refrigerator and an outlet (34) that can be connected to the inlet (21) of the refrigerator (2); and—a second compressor (4) having one or more inlets for receiving evaporated refrigerant from the refrigerator and an outlet (44) that can be connected to the inlet (21) of the refrigerator (2).

Abstract: An ice making, and delivery apparatus for making and delivering ice to different ones of a plurality of receptacle units is provided, in which ice delivered via a conduit to a diverter valve mechanism, is diverted from alignment with one ice discharge line to another, depending upon sensors in ice receptacles recognizing a level of build-up of ice in any given receptacle, for computer control of a gearmotor for moving the diverter valve from one position to another. Various controls are provided for preventing ice build-up, and for operating the diverter valve during a “dwell” period of ice movement in the conduit, as distinguished from a “push” period of ice movement in the conduit to the diverter valve. A force multiplication technique is employed for moving the diverter valve notwithstanding the presence of ice therein.

Abstract: A beverage dispenser provides numerous inventive features in its refrigeration system, diluent delivery system, concentrate delivery system, mixing and dispensing system, and control system. The refrigeration system employs a plate heat exchanger to provide on demand refrigeration of an intermittent water flow. The diluent delivery system includes a flowmeter/solenoid/check-valve assembly. The concentrate delivery system employs a positive displacement pump. The mixing and dispensing system includes a mixing nozzle that has a locking feature such that an elevated blocking surface directly faces the inlet of pressurized diluent to create turbulence. The control system receives package-specific information from a scanner and diluent flow rate information from the flowmeter, and then determines the pump speed in order to set a desired mix ratio.

Abstract: A method for controlling a refrigeration system comprising a variable compressor capacity, and at least two refrigeration entities, e.g. display cases. Suction pressure is controlled by means of permitting/preventing a flow of refrigerant into evaporator of one or more refrigeration entities. Compressor capacity is controlled to match a desired capacity level and based on a signal derived from one or more properties of the one or more refrigeration entities, said signal reflecting a possible difference between the current compressor capacity and a current refrigeration demand of the refrigeration system. Reduces wear on compressors because switching them ON/OFF is avoided to the largest extent possible. Prevents problems relating to conflicting control strategies due to control parameters, e.g. suction pressure, being controlled by means of two or more controllable parts, e.g. compressors and flow of refrigerant into refrigeration entities.

Abstract: A power management system (36) supplies power to a refrigeration unit (20) of a vehicle (22). When a vehicle engine (40) is running, the refrigeration unit receives power from a DC power source (38). When the vehicle engine is not operating, power is supplied through an AC source (46). A converter (42) within the power management system converts the AC power to Dc power and sends the power to the refrigeration unit. If the user attempts to start the vehicle engine when the refrigeration unit is receiving power through the converter, there is conflict in power supply. The power management system will activate an alarm (48) to alert the user to an attempt to power the refrigeration unit with two different power systems.

Abstract: A personal environment appliance is disclosed in which a person in a localized area can individually control the ambient conditions of the person's localized area. The control permits highly localized adjustment to suit individual preferences, thereby, reducing the impact of individual environmental preferences on the individuals. In addition to environment conditions, a variety of accessories may be provided such as beverage heaters and/or coolers.

Abstract: A composition including an effective amount of trans-1,3,3,3-tetrafluoropropene component combined with an effective amount of an alcohol selected from the group of methanol, ethanol, propanol, isopropanol, tert-butanol, isobutanol, 2-ethyl hexanol and any combination thereof, where the composition has azeotropic properties.

Abstract: A multi-circuit refrigerant system incorporates at least one component provided with a pulse width modulation control. This component can be controlled to adjust the capacity provided by the circuit incorporating the component. In this manner, the pulse width modulation component can be controlled to exactly tailor the capacity of that circuit to provide a total desired combined cooling capacity of the multiple circuits within the multi-circuit system configurations. In one embodiment, only one circuit in a multi-circuit refrigerant system incorporates a pulse width modulation controlled component. In another embodiment, a plurality of circuits are provided with pulse width modulation controlled components.

Abstract: A cooling apparatus for objects such as convenience foods and beverages has an enclosure and a vapour cycle refrigeration system. The refrigeration system includes a compressor, a condenser, a metering device and an evaporator, all connected in a circuit. Fans force air across the evaporator coils during operation of the compressor. When the compressor is ‘off’, or dormant, the evaporator fans are operated in a partial or reduced duty cycle in which the overall power draw and average power consumption is less than it would be if the evaporator fans were run continuously.

Abstract: This disclosure discusses the problems associated with the design, layout, and construction of units and equipment in air separation units. The invention of this disclosure provides a process and apparatus using multiple discrete subcoolers. The nitrogen stream exiting the cryogenic distillation columns cools streams in the subcoolers. By having at least two subcoolers, the size of the nitrogen vent (nitrogen waste or product stream) can be reduced. This saves fabrication costs and improves reliability by reducing thermal stresses in the piping and equipment. Subcoolers cool rich liquid, lean liquid, liquid oxygen, and/or liquid air streams coming from the main heat exchanger or a system of separation columns. The disclosure also discusses integration of the subcoolers with the main heat exchangers.

Abstract: A multi-circuit refrigerant system includes a plurality of circuits that are provided with distinct refrigerants. A control selectively matches a sensed environmental space conditioning challenge to selectively engage the plurality of circuits.

Abstract: A temperature controlled case is provided that includes an enclosure defining an airspace for receiving products therein, a refrigeration system configured to circulate a refrigerant through an expansion device and at least one cooling element to cool the airspace and a control module having a first predetermined setpoint corresponding to a first cooling mode and a second predetermined setpoint corresponding to a second cooling mode. The control module is configured to determine which one of the first cooling mode and the second cooling mode the refrigeration system is to operate within and to apply the corresponding predetermined setpoint for reference in modulating a position of the expansion device.

Abstract: Disclosed is a container warmer that utilizes the same compartment for heating and cooling. In optional embodiments, the unit may include a programmable timer operably connected to the heating and cooling units such that the timer may regulate activity of the units. In other embodiments, the invention may include a baby bottle warmer in which the baby bottle is placed in a water bath in a compartment, the water bath being heated or cooled by heating or cooling units, and optionally operably connected to a programmable timer.

Abstract: The invention relates to a refrigerator unit and/or a freezer unit having a space for the reception of the refrigerated goods or frozen goods, having a fan which removes air from the space, blows air into the space or circulates the air in the space and having a control unit connected to the fan which controls the fan for the purpose of influencing the temperature distribution such that it is operated in one rotary direction in a first operating state and in the other rotary direction in a second operating state. The invention further relates to a method of operating a refrigerator unit and/or a freezer unit.

Abstract: A package for housing a semiconductor chip is described. In one embodiment, the package comprises an insulation body encasing the semiconductor chip, wherein the insulation body is in direct contact with the front surface of the semiconductor chip. A refrigeration device is connected with the back surface of the semiconductor chip and is for removing substantially more heat from said semiconductor chip than the heat removed from the semiconductor chip by the insulation body. In another embodiment, a method for operating a semiconductor chip comprises cooling the semiconductor chip to a first less-than-ambient temperature by activating a refrigeration device of a package that houses the semiconductor chip. Subsequently, power is provided to the semiconductor chip, heating the semiconductor chip to a second less-than-ambient temperature.

Abstract: A refrigeration system includes a compressor for driving a refrigerant along a flow path in at least a first mode of system operation; a first heat exchanger along the flow path downstream of the compressor in the first mode; a second heat exchanger along the flow path upstream of the compressor in the first mode; and a pressure regulator or expansion device in the flow path downstream of the first heat exchanger and upstream of the second heat exchanger in the first mode, wherein the first heat exchanger is positioned within a housing which defines a flow path for heat exchange fluid and the housing defines a zone of reduced flow area along the flow path, and wherein the first heat exchanger is positioned in the zone of reduced flow area.

Abstract: The present invention comprises a gear motor assembly and control system for use with ice crushers and the other similar devices. The assembly utilizes a novel reversing circuit which allows the use of a bidirectional DC powered gear motor in existing refrigerator and freezer configurations, which heretofore used AC powered gear motors, to power ice crushing and dispensing apparatus.

Abstract: An improved concentrate/extract cartridge is provided for dispensing a liquid in an accurate and repeatable manner. The cartridge includes an electromagnetically actuated piston connected to a valve. The piston includes an exterior ring supported by a hollow interior web that is configured to permit a flow of fluid into the dispensing tube when the valve body is in contact with the valve seat. A membrane is located below the web and is in sealing contact with the internal ring when the piston is activated. This allows a precise and repeatable amount of the liquid to be dispensed with each stroke. Dispensers for dispensing the liquid from the cartridge for a number of applications are also provided. The dispensers each include an actuating coil into which the dispensing tube is inserted. A controller is connected to the coil for controlling the actuation of the piston/valve assembly for dispensing the fluid in the cartridge as required for the particular application.

Abstract: Devices designed to aid the cooling of liquids in a flexible fluid container such as a bag being dispensed over time, generally through use of a dispenser which penetrates the membrane of the bag with at least one spike. The devices are cooling packs, adapted and sized to allow interaction with the fluid in the bag, while generally inhibiting damage to the pack from the spike. The devices are designed especially to cool liquid beverages such as water, without need to include an electromechanical cooling system in the dispensing device.

Abstract: A refrigerator includes a dispenser including a moving chute configured to move from a stored position in which an outlet of the moving chute is positioned in a space defined in a refrigerator door to an operable position in which the outlet of the moving chute is positioned outside of the refrigerator door.

Abstract: A local air conditioning system for a vehicle includes a local air conditioning unit for performing one of a cooling operation and a heating operation for a predetermined portion of a seat of the vehicle. In the local air conditioning system, information regarding a user is acquired, and a current scene is identified based on the acquired information. The local air conditioning unit is controlled to perform one of the cooling operation and the heating operation for the predetermined portion of the seat on condition that the current scene is identified as a getting-in-vehicle scene in which the user gets in the vehicle and sits on the seat. For example, the predetermined portion of the seat is a portion corresponding to a high body temperature portion of a user, such as a nape of a neck and backs of knees.

Abstract: A soft freeze assembly for a refrigerator including a freezer storage compartment having a first temperature includes a second storage compartment positioned within the freezer storage compartment. A heat source is positioned with respect to the second storage compartment and configured to heat air within the second storage compartment to a second temperature greater than the first temperature within the freezer storage compartment. A controller is in operational control communication with the heat source and configured to operate the heat source.

Abstract: A multi-purpose cargo hold, carrier vessel, and shipping methods for circulating conditioned air through multiple levels and types of cargo situated therein. Disclosed are apparatus and methods for shipping and conditioning air surrounding cargo on a carrier vessel comprising the steps of loading cargo onto a loading means; forming a plurality of air gaps throughout the cargo in the cargo hold; placing supply and return air plenums in fluid communication with one another; and delivering and circulating conditioned air to cargo via an air conditioning means.

Abstract: A fluid transfer device and a method for conveying a fluid from a fluid transfer device to a rotating member are provided. The fluid transfer device includes a housing disposed around a first rotating member extending along an axis. The housing has a first plurality of apertures extending therethrough that communicate with the fluid source. The first rotating member has a second plurality of passageways extending from a first exterior surface of the first rotating member to a third passageway extending generally axially within the first rotating member. Further, at least a portion of the second plurality of passageways communicate with at least a portion of the first plurality of apertures, wherein the fluid flows through the first plurality of apertures and the second plurality of passageways to the third passageway in the first rotating member.

Abstract: A gas compression system includes a flow of compressed gas, a separator positioned to receive the flow of compressed gas and discharge a second flow of compressed gas and a flow of condensate, and a flow of compressed refrigerant. A heat exchanger is positioned to receive the flow of condensate and the flow of compressed refrigerant. The heat exchanger is arranged such that the flow of condensate cools the flow of refrigerant.

Abstract: The invention pertains to heat transfer compositions, particularly to automobile refrigerants comprising a hydrofluoroalkene, an iodocarbon, a polyol ester and at least one compound comprising trifluoromethane, methyl iodide, heptafluorobutane or propene.

Abstract: A method of providing variable cooling includes operating a cooling element to cool an air flow by a first cooling capacity, operating a heating element to heat the air flow by a first heating capacity that adjusts the first cooling capacity towards a first desired total cooling capacity, determining a second desired total cooling capacity, controlling the cooling element to cool the air flow by a second cooling capacity that is greater than the second desired total cooling capacity, and controlling the heating element to heat the air flow by a second heating capacity that adjusts the second cooling capacity towards the second desired total cooling capacity. Further embodiments and cooling systems are also disclosed.

Abstract: A refrigerator and a safety control method thereof, which is capable of ensuring protection from a high voltage applied to a shelf on which food is placed in order to improve food preservation. The safety control method of a refrigerator having a storage chamber which stores food, the method includes sensing a chamber temperature of the storage chamber, comparing the sensed chamber temperature with a predetermined setting temperature and generating a high voltage when the chamber temperature is less than the predetermined setting temperature, supplying the generated high voltage to the inside of the storage chamber to preserve the food, determining whether a high voltage cutoff condition occurs while the high voltage is supplied to the inside of the storage chamber, and cutting off the high voltage supplied to the inside of the storage chamber when the high voltage cutoff condition occurs.

Abstract: A freeze plate is provided. The freeze plate includes a freeze plate surface, a sealed chamber adjacent the freeze plate surface, one or more refrigerant lines in said sealed chamber, and a fluid in said sealed chamber in thermal contact with the freeze plate surface and the one or more refrigerant lines.

Abstract: On cold filling of pressure containers the filling gas is cooled before introduction into the pressure container to be filled. On completion of the filling process the pressure container is sealed in a pressure-tight manner. As the gas warms up the pressure in the pressure container rises rapidly. According to the invention, the pressure container is cooled before the introduction of the filling gas. The filling gas cools rapidly by means of heat transfer to the pressure container, whereby the filling capacity of the pressure container is considerably increased. Said method is particularly suitable for the filling of small tanks, in particular, for gas-driven vehicles and fuel-cell systems.

Abstract: A re-circulating cooling system can be used with a curing system in order to reduce the exhaust requirements for the system. Further, using a cooling fluid such as nitrogen reduces the production of ozone and the sealing requirements for the system. A simple heat exchanger can be used between return and supply reservoirs in order to remove heat added to the re-circulating fluid during circulation past the curing radiation source. The nitrogen can come from a nitrogen source, or from a membrane or other device operable to split feed gas into its molecular components to provide a source of gas rich in nitrogen. An ozone destruction unit can be used with such a cooling system to reduce the amount of ozone to acceptable levels, and to minimize consumption of the nitrogen. A catalyst can be used to deplete the ozone that does not get consumed during the reaction.

Abstract: To provide a cooling method of a superconducting cable line wherein moistures contained in the cable in the superconducting cable line after laid is removed before cooling, so that solidification of the moistures can be prevented from clogging of piping including a coolant flow channel and a return pipe. There is provided an inert gas generating vessel so that before the coolant is flown into the superconducting cable line 15, the inert gas is blown into the cable line from an inflow pipe 23 connected with a supply pipe 19? and is discharged from a discharge pipe 22 together with the gas. The inert gas is preheated by a heater 3 before feeding it into the cable line. The discharge pipe 22 connected with a discharge side B of the return pipe 19 is provided with a moisture measuring instrument 20 to measure a moisture content of the discharged gas.

Abstract: A lighting device for illuminating ice has a sheet of light-transmitting film located below an ice layer and coupled to a light source. The index of refraction of the light-transmitting film is greater than that of the adjoining ice or air so that the light within the film experiences substantial internal reflection. Light is emitted from the film (and the ice surface) at emission regions that disrupt internal reflection.

Abstract: A system for controlling the cooling of small milk quantities in a cooling tank (4). An agitation pipe (2) extended through a regular milk outlet (26) in a first end wall (6) of the tank is provided, having a nozzle end (32) for introducing incoming/re-circulated milk onto a milk cooling surface (14) at a predetermined position (dp). The position (dp) being situated (1) between a first end wall (6) and a central part of the tank (4) and laterally displaced (b) relative to the perpendicular central axis of the tank. The nozzle end (32) is directed towards a second end wall (8) of the tank (4). Agitation is performed by the agitation pipe (2) upon demand or when the milk quantity is insufficient for a regular agitator element (27) to work properly.

Abstract: A chilled item server is disclosed including an outer barrel formed of thermoplastic material that has a generally cylindrical shape, substantially vertical sides, a generally flat, closed bottom, and an open top having an annular ledge. An inner liner fits within the outer barrel and has a generally elongated truncated pyramidal shape, a generally flat bottom, an open top with an extended rim formed to compliment the generally square opening shape of the outer barrel and to rest on the annular ledge. A chamber is located between the inner liner and the outer barrel and is filled with polystyrene foam. At least one freezer panel is formed of appropriate size and shape to fit within the inner liner. The freezer panel is formed of thermoplastic material and arranged in a syncline. The freezer panels have cavities within each freezer panel that is filled with 2% saline solution. Casters are mounted to the generally flat bottom of the outer barrel.

Abstract: A slush hydrogen production device (10) utilizes a hydrogen slushifier magnetic refrigerator (30) having a wheel (50) of material exhibiting the magnetocaloric effect. The wheel is rotated through a magnetic field of varying intensity around the circumference of a wheel housing (36) created by the windings of superconductive magnets (56). The material of the wheel (50) follows a magnetic Carnot cycle as the wheel rotates (36) through regions of low temperature heat transfer and high temperature heat transfer. Liquid hydrogen is supplied to the regions of low and high temperature heat transfer through inlet pipes (39 and 42). Gaseous hydrogen is produced in the high temperature heat transfer region and vented away by an outlet pipe (48). Solid hydrogen is produced in the low temperature heat transfer region by direct solidification upon the magnetic wheel (50); and is removed by scrapers (76) and deposited in a compartment (26) where it mixes with liquid hydrogen to form slush hydrogen.