Refrigeration device and method

Abstract

Refrigeration device intended to extract heat from at least one member by heat exchange with a working fluid circulating in the working circuit comprising in series: a fluid compression mechanism a fluid cooling mechanism, preferably isobaric or substantially isobaric, a fluid expansion mechanism, and a fluid heating mechanism, in which device the compression mechanism is of the centrifugal compression type and consists of two compression stages arranged in series in the circuit, the device comprising two respective electric drive motors driving the two compression stages, the expansion mechanism consisting of a turbine coupled to the motor of one of the compression stages, the turbine of the expansion mechanism being coupled to the drive motor of the first compression stage.

1 - 14 . (canceled) 
     
     
         15 . A device for low-temperature refrigeration between −100° C. and −273° C. comprising a working circuit containing a working fluid, the device being intended to extract heat from at least one component by heat exchange with the working fluid circulating in the working circuit, the working circuit comprising in series: a mechanism for compression of the fluid, preferably isentropic or substantially isentropic, a mechanism for cooling the fluid, preferably isobaric or substantially isobaric, a mechanism for expansion of the fluid, preferably isentropic or substantially isentropic and a mechanism for heating the fluid, preferably isobaric or substantially isobaric, in which the compression mechanism is of the type with centrifugal compression and consists of two compression stages, a first compression stage and a second compression stage respectively, arranged in series in the circuit, that is, the device has only two compressors each constituting one of the two compression stages, the device comprising only two electric drive motors of the two compression stages respectively, the expansion mechanism consisting of a turbine coupled to the motor of one of the compression stages, that is, the device has only one turbine constituting the expansion mechanism, characterized in that the turbine of the expansion mechanism is coupled to the drive motor of the first compression stage. 
     
     
         16 . The device of claim  1 , wherein the electric drive motor of the first compression stage comprises an output shaft, one end of which carries the first compression stage and causes it to rotate by direct coupling and the other end of which carries and is caused to rotate by the turbine by direct coupling. 
     
     
         17 . The device of  claim 15 , wherein the two motors are identical or similar. 
     
     
         18 . The device of  claim 15 , wherein the cooling mechanism comprises an intermediate cooling exchanger located between the first compression stage and the second compression stage, for cooling the fluid leaving the first compression stage before it enters the second compression stage. 
     
     
         19 . The device of  claim 15 , wherein the motors are high-speed motors, i.e. motors for which the product of the power P in kW times the speed N in revolutions per minute squared (P·N 2 ) is between 5.10 10  and 5.10 12 . 
     
     
         20 . The device of  claim 15 , wherein the rotary speed of the two motors is identical. 
     
     
         21 . The device of  claim 15 , wherein the mechanical power of the two motors is identical. 
     
     
         22 . The device of  claim 15 , wherein the drive motor of the second compression stage also mechanically drives a circulating pump or additional compressor configured for circulating a cooling fluid of the motor or motors. 
     
     
         23 . The device of  claim 15 , wherein the two compression stages each consist of a centrifugal compressor possessing an optimum specific speed determined by maximizing the energy efficiency of the compressor and in that the device is configured to maintain the specific speed of the compressors between 70% and 130% and preferably between 80% and 120% of the optimum specific speed and even more preferably between 90% and 110% of the optimum specific speed. 
     
     
         24 . The device of  claim 15 , wherein it comprises an electronic control unit of the device and comprises a unit for data storage and processing, the electronic control unit being configured notably for controlling at least one of the motors. 
     
     
         25 . The method of refrigeration of a cold source using a refrigerating device of  claim 15 , in which heat exchange takes place between the working fluid cooled after it leaves the expansion mechanism and the component to be cooled. 
     
     
         26 . The method of refrigeration of  claim 25 , wherein the specific speed of the compressors is maintained between 70% and 130% and preferably between 80% and 120% and even more preferably between 90% and 110% of their optimum specific speeds.