Process and plant for the production of liquid hydrogen with a liquefier that has a variable cooling power dependent on the electrical power consumed. The liquefier is supplied with electricity by a first source of electricity at least one additional source of electricity that provides an intermittent or variable amount of electricity over time. Liquid hydrogen is produced at first thermodynamic conditions when the liquefier is supplied with a predetermined nominal electrical energy level and produced at subcooled conditions, with respect to the first thermodynamic conditions, when electricity supplied to the liquefier exceeds the nominal level.

Disclosed is a low-temperature refrigeration device comprising a working circuit that forms a loop and contains a working fluid, the device further comprising a cooling exchanger for extracting heat from at least one member by exchanging heat with the working fluid, the working circuit forming a cycle comprising, connected in series: a compression mechanism, a cooling mechanism, an expansion mechanism and a heating mechanism, wherein the mechanism for cooling the working fluid and the heating mechanism comprise a common heat exchanger in which the working fluid flows in opposite directions in two separate transit portions of the circuit according to whether it is cooled or heated, the device being designed to ensure equal mass flow rates in the two transit portions in the common heat exchanger, the device also comprising a bypass for bypassing one of the two transit portions, said bypass comprising a bypass valve which, in the open state, changes the mass flow rate in one of the two transit portions.

The invention relates to a method for adjusting a cryogenic refrigeration apparatus including a plurality of liquefiers/refrigerators arranged in parallel in order to cool a single device. The method includes a step of calculating in real time the dynamic mean value of at least one operating parameter for all the liquefiers/refrigerators. The apparatus controlling in real time the at least one valve for controlling the stream of working gas of at least one liquefier/refrigerator in accordance with the difference between the instantaneous values of the parameter relative to said dynamic converge toward said dynamic mean value.

An installation for refrigerating a same application by means of a single refrigerator/liquefier or several refrigerators/liquefiers arranged in parallel, the refrigerator(s)/liquefier(s) using a working gas of the same type having a low molar mass, each refrigerator/liquefier comprising a compression station to compress the working gas, a cold box intended for cooling the working gas at the outlet of the compression station, the compression station comprising only compression machines of the lubricated screw type and systems for removing the oil from the working fluid at the outlet of the compression machines, and the compression station comprises a plurality of compression machines defining several levels of pressure for the working fluid, the compression station comprising at least two compression machines defining at least two levels of pressure increasing above the level of pressure of the fluid at the inlet of the compression station, two main compression machines being arranged in series and defining, at their respective fluid outlet, levels of pressure respectively called “low” and “high”, another secondary compression machine being supplied at the inlet with a fluid coming from the cold boxes at an intermediate level of pressure called “medium” between the low and high levels, this secondary compression machine also defining, at its fluid outlet, a “high” level of pressure.

The present invention relates to a refrigerant composition. According to the invention it is envisioned that the composition comprises comprising an inert gas selected from nitrogen, argon, neon and a mixture thereof, and a mixture of at least two C.sub.1-C.sub.5 hydrocarbons. The present invention further relates to the use of the refrigerant composition in a method for liquefying a gaseous substance, particularly hydrogen or helium.

Certain embodiments of the invention relate to a facility for refrigerating a fluid to a cryogenic temperature, comprising a circuit for the fluid to be refrigerated, comprising an upstream end connected to a source and a downstream end connected to a refrigerated and/or liquefied fluid collection member, the facility comprising at least one exchanger for precooling the fluid leaving the upstream end, the precooling exchanger exchanging heat with a precooling circuit composed of a flow of vaporization gas from a user, the facility further comprising a heat exchanger assembly for cooling by heat exchange with the circuit of fluid to be cooled downstream of the precooling exchanger, the facility comprising a device for cooling by heat exchange with at least a part of the cooling heat exchanger assembly, said cooling device comprising a first refrigerator with a refrigeration cycle of a cycle gas in a working circuit, the cycle gas preferably comprising hydrogen and/or helium, the working circuit of the first refrigerator comprising a member for compressing the cycle gas, a member for cooling the cycle gas, a member for expanding the cycle gas and a member for heating the cycle gas, the precooling exchanger being composed of at least one of the following materials: stainless steel or grades of stainless steel, Inconel, nickel, titanium or plastic material compatible with use at cryogenic temperatures.

A cryogenic refrigeration system and a corresponding method for increasing the cooling efficiency of the system, preferably the cooling of a thermally coupled load. Accordingly, the system comprises a supply means for providing a supply flow of a cryogenic refrigerant, a compressor fluidly coupled to said supply means and configured to compress the supplied cryogenic refrigerant, and a cold box fluidly coupled to the compressor, said cold box comprising a first expansion device and a first heat exchanger, wherein the first expansion device is configured to receive the compressed cryogenic refrigerant from the compressor and expand it and provide the expanded refrigerant to the first heat exchanger, and wherein the first heat exchanger is configured to be thermally coupled to a load. The system furthermore comprises a second heat exchanger arranged in the cold box comprising at least a first and second heat exchanging section.

A process for liquefying hydrogen gas including the following is disclosed: cooling the hydrogen gas to an intermediate temperature by heat exchange with a refrigerant circulating in a refrigeration loop provided with a higher temperature expander and a lower temperature expander, wherein the outlet stream from the lower temperature expander contains some condensed refrigerant; a means is provided of separating the condensate from the circulating refrigerant; and further cooling of the hydrogen gas by heat exchange with evaporation and reheating of the said condensate.

The fluid in the refrigeration loop is typically methane (such as natural gas after removal of carbon dioxide, water vapor and other impurities), or nitrogen, or a mixture thereof.

A raw material gas liquefying device includes a feed line which feeds a raw material gas, a refrigerant circulation line which circulates a refrigerant, the refrigerant circulation line including an expansion unit of a turbine type which expands the refrigerant to generate cryogenic energy, and an expansion unit entrance valve provided at an entrance side of the expansion unit, a heat exchanger which exchanges heat between the raw material gas and the refrigerant, a cooler which performs initial cooling of the raw material gas and the refrigerant by heat exchange with liquid nitrogen, and a controller which manipulates the opening rate of the expansion unit entrance value and performs a feedback control so that the rotation speed of the expansion unit reaches a predetermined target value, and outputs the opening rate command to the expansion unit entrance valve, at start-up and stop of the expansion unit.

Low-temperature refrigeration device arranged in a frame and comprising a working circuit forming a loop and containing a working fluid, the working circuit forming a cycle comprising in series: a compression mechanism, a cooling mechanism, an expansion mechanism and a heating mechanism, the device comprising a refrigeration heat exchanger intended to extract heat from at least one member by exchanging heat with the working fluid, the mechanisms for cooling and reheating the working fluid comprising a common heat exchanger in which the working fluid transits in counter-flow in two separate transit portions of the working circuit, the compression mechanism comprising at least two compressors and at least one motor for driving the compressors, the working fluid expansion mechanism comprising at least one rotary turbine, the device comprising at least one drive motor comprising a drive shaft, one end of which drives a compressor and the other end of which is coupled to a turbine, the motor being attached to the frame at at least one fixed point, the common heat exchanger being attached to the frame at at least one fixed point, the two counter-flow transit portions of the common heat exchanger being orientated in a longitudinal direction of the frame, the drive shaft of the drive motor being orientated in a direction parallel or substantially parallel to the longitudinal direction and the turbine and the compressor being arranged relatively longitudinally such that the turbine is located longitudinally on the side corresponding to the relatively cold end of the common heat exchanger when the device is being operated and the compressor is located longitudinally on the side corresponding to the relatively hot end of the common heat exchanger when the device is being operated.