A regenerative refrigerator system and method for remote cooling using a cold end DC

Abstract

The application discloses a regenerative refrigerator system and method for realizing remote cooling by leading out cold-end direct current, which comprises a regenerative refrigeration module, a remote throttling refrigeration module and a direct current loop module; the regenerative refrigeration module comprises a refrigerator compression device, a cold finger and a radiation screen which are connected in sequence; the remote throttling refrigeration module comprises a remote pipeline and a throttling heat exchanger; high-pressure direct current gas led out from a cold-end heat exchanger flows to a throttling element in the throttling heat exchanger through the remote pipeline, and directly contacts with a cooling object to exchange heat; the direct current loop module comprises a direct current pipeline, a part of the direct current pipeline directly contacts with the radiation screen and the cold finger, coldness of the direct current is utilized to cool the radiation screen and the cold finger, a flow rate is controlled through a direct current control assembly, and finally the direct current directly returns to a high-pressure pipeline of the refrigerator compression device to complete external circulation. The application can realize remote cooling by leading out a direct current from a cold end without reducing original refrigeration performance of a refrigerator.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration technology, in particular to a regenerative refrigerator system and method for realizing remote cooling supply by leading out cold-end direct current. BACKGROUND

[0002] Regenerative cryogenic refrigerators, such as pulse tube refrigerators, Stirling refrigerators, GM refrigerators, etc., have a wide range of applications in low-temperature superconducting and natural gas liquefaction due to their simple structure, high reliability, flexibility and other advantages.

[0003] Many occasions currently require remote cooling to reduce the interference of the refrigerator system on the cooled object, such as precision superconducting devices, infrared imaging devices, satellite communication stations of military bases, and image diagnosis centers of medical centers. However, the traditional regenerative refrigerator cannot directly provide remote cooling, and usually requires an intermediate circulating refrigerant to realize the transmission of cold energy from the cold end of the refrigerator to the cooled object, such as low-temperature helium circulation or heat pipe circulation. However, both of these methods have certain disadvantages, such as helium circulation, which requires an additional low-temperature helium pump to achieve helium flow, increasing the complexity of the system and energy consumption. At the same time, in terms of heat transfer, the circulating helium first exchanges heat with the refrigerator and then transfers the cold energy to the cooled object, which increases the overall heat transfer thermal resistance. Although heat pipes can help reduce the thermal resistance of long-distance heat transfer, their design and manufacture are complex, and their heat transfer temperature is limited by the phase change temperature of the working medium, making it difficult to achieve the transmission of cold energy at different temperatures. Therefore, it is of great application value to optimize and modify the existing regenerative refrigerator to realize its remote direct cooling.

[0004] In traditional regenerative refrigerators, there is only alternating flow and no direct flow. In early research, direct current was considered to be the cause of deteriorating the performance of the refrigerator, so researchers made many efforts to suppress it. With further research, it was found that allowing a certain amount of direct current flow within a certain size or direction can improve the performance of the regenerative refrigerator in the liquid helium temperature range.

[0005] A high-efficiency regenerative refrigerator system is disclosed in Chinese patent document CN118089263A, which uses cold-end direct current technology. The direct current fluid drawn from the cold-end heat exchanger of the regenerator of the cold finger is throttled and heat-exchanged in the throttling cold-end heat exchanger, and then enters the direct current pipeline. The direct current pipeline is in contact with the copper sleeve heat exchanger fixed on the cold finger, and the cold energy generated by the direct current is used to cool the cold finger. However, this patent does not realize remote cooling function, and the low-temperature pump installed on the direct current circuit increases the energy consumption of the overall system.

[0006] In addition, most of the current patents, such as patents with publication numbers CN118623553A and CN114791203A, use cold-end direct current for refrigeration or gas liquefaction, and do not realize remote cooling function. The way of extracting refrigeration capacity belongs to indirect refrigeration, the heat transfer resistance is large, the cold energy loss is large, and the helium flow is realized by using an additional low-temperature helium pump in the direct current loop, which increases the complexity of the system and increases the energy consumption. SUMMARY

[0007] The application provides a regenerative refrigerator system and method for realizing remote cooling by leading out cold-end direct current, which can realize remote cooling by leading out a direct current from the cold end without reducing the original refrigeration performance of the refrigerator.

[0008] A regenerative refrigerator system for realizing remote cooling by leading out cold-end direct current, comprising a regenerative refrigeration module, a remote throttling refrigeration module and a direct current loop module.

[0009] The regenerative refrigeration module comprises a refrigerator compression device, a cold finger and a radiation screen connected in sequence, and the refrigerator compression device is provided with a low-pressure gas inlet, a high-pressure gas inlet and a gas supplement inlet, which are respectively connected with a low-pressure pipeline, a high-pressure pipeline and a helium pipeline; a low-pressure gas distribution valve and a high-pressure gas distribution valve are respectively arranged in the low-pressure pipeline and the high-pressure pipeline, and the two pipelines are connected with the cold finger through a transmission pipeline after being merged;

[0010] The remote throttling refrigeration module comprises a remote pipeline and a throttling heat exchanger, and the two ends of the remote pipeline are respectively connected with a cold-end heat exchanger of the cold finger and a throttling element in the throttling heat exchanger; the high-pressure direct current gas led out from the cold-end heat exchanger flows to the throttling element in the throttling heat exchanger through the remote pipeline to perform throttling refrigeration, and at the same time, directly contacts with the object to be cooled to perform heat exchange, thereby realizing remote throttling refrigeration.

[0011] The direct current loop module comprises a direct current pipeline and a direct current control assembly, and the two ends of the direct current pipeline are respectively connected with the throttling element in the throttling heat exchanger and the high-pressure pipeline of the refrigerator compression device; a part of the direct current pipeline directly contacts with the radiation screen and the cold finger, and the cold energy of the direct current is used to cool the radiation screen and the cold finger, the flow is controlled through the direct current control assembly, and finally the direct current directly returns to the high-pressure pipeline of the refrigerator compression device to complete external circulation.

[0012] Further, the direct current control assembly comprises a butterfly valve arranged on the remote pipeline, and a first needle valve and a first pressure sensor arranged on the direct current pipeline.

[0013] Further, a part of the direct current pipeline is wound around the outer wall of the radiation screen and the outer wall of the first-stage cold end of the cold finger.

[0014] Optionally, the regenerative refrigeration module is one of a GM refrigerator, a GM pulse tube refrigerator, a Stirling refrigerator, a Stirling pulse tube refrigerator, and a VM refrigerator.

[0015] Optionally, the regenerative refrigeration module has a coaxial type, a U type, or a straight line type, and has a single stage, two stages, or multiple stages, and has a thermal coupling or a gas coupling.

[0016] Optionally, the throttling element in the throttling heat exchanger has a capillary tube or a throttling hole, and has one or more.

[0017] Further, the compressor of the refrigerator is provided with a low-pressure inlet pressure gauge, a high-pressure outlet pressure gauge, a display screen, and a control panel.

[0018] Further, the gas supplementing port is connected with a helium tank through a helium pipeline, and the helium pipeline is provided with a second needle valve, a second pressure sensor, and a pressure reducing valve.

[0019] A remote throttling refrigeration method is provided, which uses the high-efficiency regenerative refrigerator system, and the specific process is as follows:

[0020] The gas working substance with working pressure is filled into the regenerative refrigeration module, the internal pressure is ensured to be in the range of 0.3-2.5 MPa, the frequency of the compressor of the refrigerator is adjusted, and the compressor of the refrigerator is started to start cooling.

[0021] When the temperature of the cold end heat exchanger of the cold finger is stabilized at 3-10 K, the butterfly valve and the first needle valve in the direct current control assembly are opened in sequence to start the direct current circulation, and when the temperature of the throttling heat exchanger is stabilized, the corresponding refrigeration temperature and refrigeration capacity are obtained at the throttling heat exchanger.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] 1. Compared with the traditional regenerative refrigerator system, the cold quantity extracted by the cooled object must be exchanged through the refrigerant heat exchanger, which belongs to indirect heat exchange, and the thermal resistance is large. The throttling heat exchanger is used to extract the cold quantity of the refrigerator through direct contact, reduce the heat exchange thermal resistance, reduce the loss, and improve the refrigeration performance.

[0024] 2. The direct current is throttled and exchanged at the remote heat exchanger, remote refrigeration is realized, and the application scene and range of the refrigerator are widened.

[0025] 3. The cold end direct current is introduced into the compressor after being cooled by the regenerator through the radiation screen outer wall heat exchange assembly and the cylinder outer wall heat exchange assembly, the heat exchange is strengthened, the total heat loss of the regenerator is reduced by using the direct current cold quantity, and the performance of the refrigerator is further improved.

[0026] 4. Compared with the existing regenerative refrigerator system using cold-end direct current, the application does not use a cryogenic pump, directly uses a direct current through a regenerative refrigerator high-pressure pipeline, saves energy consumption and reduces cost. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Fig. 4 is a 4.2K refrigeration performance and direct current flow curve when different direct current pipes are used.

[0028] Figure 2 Fig. 5 is a structure schematic diagram of a regenerative refrigerator system of the application for leading out cold-end direct current to realize remote cooling.

[0029] Figure 3 Fig. 6 is a structure schematic diagram of a throttle heat exchanger used.

[0030] Figure 4 Fig. 7 is a structure schematic diagram of a radiation screen outer wall heat exchange assembly and a first-stage cold-end outer wall heat exchange assembly.

[0031] In the figure: 1 - refrigerator compression device; 2 - low-pressure gas inlet; 3 - high-pressure gas inlet; 4 - cold finger; 5 - cold-end heat exchanger; 6 - radiation screen; 7 - butterfly valve; 8 - remote pipeline; 9 - throttle heat exchanger; 10 - to-be-cooled object; 11 - No. 1 needle valve; 12 - No. 1 pressure sensor; 13 - radiation screen outer wall heat exchange assembly; 14 - first-stage cold-end outer wall heat exchange assembly; 15 - No. 2 needle valve; 16 - No. 2 pressure sensor; 17 - pressure reducing valve; 18 - helium tank; 19 - low-pressure gas distribution valve; 20 - high-pressure gas distribution valve; 21 - direct current pipeline; 22 - air supplement inlet; 23 - low-pressure gas inlet pressure gauge; 24 - high-pressure gas outlet pressure gauge; 25 - compression device display screen; 26 - compression device control panel. DETAILED DESCRIPTION

[0032] The application will be further described in detail below in combination with the drawings and examples, and it should be pointed out that the following examples are intended to facilitate the understanding of the application and do not limit the application in any way.

[0033] In theory, for a regenerative refrigerator, according to the first law of thermodynamics, the energy flow in the regenerator at steady state can be expressed as:

[0034]

[0035] wherein, is the pressure-enthalpy flow caused by the actual gas effect, is the heat-enthalpy flow caused by the irreversible heat exchange, is the heat conduction term of the regenerator.

[0036] Ignoring the shuttle loss and the heat loss of the cylinder wall, the discharge device wall, etc., the refrigeration capacity of the cold end can be expressed as:

[0037]

[0038] wherein, is the acoustic power of the cold end.

[0039] For a regenerative refrigerator with a direct current, according to the first law of thermodynamics, the energy flow in the regenerator at steady state can be expressed as:

[0040]

[0041] wherein, is the enthalpy flow caused by the direct current.

[0042] Ignoring the shuttle loss and the heat loss of the cylinder wall, the discharge device wall, etc., the refrigeration capacity of the cold end can be expressed as:

[0043]

[0044] Compared with the case without a direct current, the presence of a direct current in the regenerator changes the internal energy flow, because the enthalpy flow caused by the direct current In order to maintain the balance of energy, the pressure enthalpy flow in the regenerator The heat enthalpy flow caused by irreversible heat exchange is reduced, while the total energy flow changes little. From the theoretical analysis, introducing a direct current into the regenerative refrigerator system will not have a negative impact on the overall refrigeration capacity of the refrigerator. Based on this theoretical derivation, the applicant conducted an experimental verification at a refrigeration temperature of 4.2K, and monitored the corresponding changes in the performance of the refrigerator as the direct current flow changed.

[0045] As Figure 2 shown, a regenerative refrigerator system for drawing a cold end direct current to realize remote cooling, comprising a regenerative refrigeration module, a remote throttling refrigeration module and a direct current loop module.

[0046] The regenerative refrigeration module comprises a refrigerator compression device 1, a low-pressure gas inlet 2, a high-pressure gas inlet 3, a gas supplement inlet 22, a low-pressure gas distribution valve 19, a high-pressure gas distribution valve 20, a low-pressure gas inlet pressure gauge 23, a high-pressure gas outlet pressure gauge 24, a compression device display screen 25, a compression device control panel 26, a cold finger 4, a cold end heat exchanger 5, and a radiation screen 6.

[0047] The low-pressure gas inlet 2, the high-pressure gas inlet 3 and the helium gas inlet gas supplement inlet 22 are respectively connected to the low-pressure pipeline, the high-pressure pipeline and the helium pipeline; the low-pressure pipeline and the high-pressure pipeline are respectively provided with the low-pressure gas distribution valve 19 and the high-pressure gas distribution valve 20, and the two pipelines are connected to the cold finger 4 through the transmission pipeline after being combined.

[0048] The gas supplementing port 22 is connected with the helium tank 18 through a helium pipeline, and the helium pipeline is provided with a second needle valve 15, a second pressure sensor 16 and a pressure reducing valve 17.

[0049] The remote throttling refrigeration module comprises a remote pipeline 8 and a throttling heat exchanger 9. Two ends of the remote pipeline 8 are connected with the cold end heat exchanger 5 of the cold finger 4 and the throttling element in the throttling heat exchanger 9 respectively. The high-pressure direct current gas led out from the cold end heat exchanger 5 flows to the throttling element in the throttling heat exchanger 9 through the remote pipeline 8 to perform throttling refrigeration, and at the same time, directly contacts the object to be cooled 10 to perform heat exchange, thereby realizing remote throttling refrigeration.

[0050] The direct current loop module comprises a direct current pipeline 21, a butterfly valve 7, a first needle valve 11, a first pressure sensor 12, a radiation screen outer wall heat exchange assembly 13 and a first cold end outer wall heat exchange assembly 14. Two ends of the direct current pipeline 21 are connected with the throttling element in the throttling heat exchanger 9 and the high-pressure pipeline of the refrigeration compressor device 1 respectively. The radiation screen outer wall heat exchange assembly 13 and the first cold end outer wall heat exchange assembly 14 in the direct current pipeline 21 directly contact the radiation screen 6 and the cold finger 4, and utilize the direct current cold energy to cool the radiation screen 6 and the cold finger 4. The flow is controlled through the direct current control assembly, and finally the direct current directly returns to the high-pressure pipeline of the refrigeration compressor device 1 to complete external circulation.

[0051] As shown in Figure 3 , the throttling heat exchanger 9 is a heat exchanger with a throttling structure arranged inside, such as a capillary tube or a throttling hole. The pipeline at two ends is connected with the cold end heat exchanger of the heat exchanger and the direct current pipeline respectively.

[0052] As shown in Figure 4 , the radiation screen outer wall heat exchange assembly 13 and the first cold end outer wall heat exchange assembly 14 are wound on the outer wall of the radiation screen 6 and the first cold end outer wall of the cold finger 4 by the direct current pipeline layer by layer.

[0053] However, the existing method of using the led-out direct current to improve the performance of the regenerative low-temperature refrigerator system still has some deficiencies. The deficiencies are that the object to be cooled 10 can only exchange heat with the cold end of the refrigerator through the refrigerant, and the heat exchange thermal resistance is large; long-distance refrigeration cannot be realized, and the application scenarios are limited; the led-out direct current needs to be pumped to increase the pressure and then delivered back to the pipeline through the low-temperature pump, thereby increasing the energy consumption.

[0054] The present application realizes remote cooling by leading straight flow from the cold end of the regenerator, and supplies cooling by direct contact of the object to be cooled with the throttling heat exchanger, thereby reducing heat exchange resistance and heat exchange loss compared with the conventional cooling mode. The present application realizes back cooling of the radiation screen and cold finger by using the throttling heat exchanger at the cold end without increasing additional operation cost, and fully utilizes the intermediate refrigeration power of the regenerator. In addition, the straight flow led from the cold end does not need additional low-temperature pump operation, so that helium gas returns to the high-pressure pipeline to complete external circulation, saving energy consumption, thereby improving the performance of the refrigerator as a whole.

[0055] The working process of the embodiment is as follows:

[0056] The system is installed according to the above process and requirements. After installation, the system components and pipelines are vacuumed to 10 -1 Pa or so, and then the pressure relief valve 17 and the second needle valve 15 are opened to charge the gas working medium, and vacuumed to 10 -1 Pa or so after repeating 3-4 times. Finally, the gas working medium at working pressure is charged into the regenerative refrigerator to ensure that the internal pressure is within the range of 0.3-2.5 MPa, which ensures the purity of the working medium in the system. The refrigerator is driven by a compressor motor, and the rotary valve and the discharger operate at a certain frequency. When starting, the compressor frequency is adjusted through the compressor control panel 26, and the power of the refrigerator compression device 1 is turned on, and the refrigerator starts to cool. When the temperature of the cold end heat exchanger 5 of the cold finger 4 is stabilized at 3-10 K, the butterfly valve 7 and the first needle valve 11 are opened in turn to start the straight flow circulation and make the system work normally until the temperature of the cold end heat exchanger 5 and the throttling heat exchanger 9 is stable, that is, the corresponding refrigeration temperature and refrigeration capacity can be obtained at the cold end heat exchanger 5 and the throttling heat exchanger 9. After heat exchange is completed, helium gas will back cool the radiation screen and the outer wall of the primary cold end, fully utilize the excess cold energy to further improve the overall performance of the regenerative refrigerator, and finally return to the high-pressure pipeline to complete external circulation.

[0057] The above embodiment describes the technical solutions and advantages of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the present application. Any modification, supplement and equivalent replacement within the principle range of the present application should be included in the protection range of the present application.

Claims

1. A regenerative refrigerator system for remote cooling by drawing off a cold end direct current, characterized by, The application relates to a heat regenerative refrigeration module, a remote throttling refrigeration module and a direct current loop module. The heat regenerative refrigeration module comprises a refrigeration compressor device (1), a cold finger (4) and a radiation screen (6) which are sequentially connected; the refrigeration compressor device (1) is provided with a low-pressure gas inlet (2), a high-pressure gas inlet (3) and a gas supplement inlet (22) which are respectively connected with a low-pressure pipeline, a high-pressure pipeline and a helium pipeline; a low-pressure gas distribution valve (19) and a high-pressure gas distribution valve (20) are arranged in the low-pressure pipeline and the high-pressure pipeline respectively; and the two pipelines are connected with the cold finger (4) through a transmission pipeline after being combined. The remote throttling refrigeration module comprises a remote pipeline (8) and a throttling heat exchanger (9); the two ends of the remote pipeline (8) are respectively connected with a cold end heat exchanger (5) of the cold finger (4) and a throttling element in the throttling heat exchanger (9); high-pressure direct current gas led out from the cold end heat exchanger (5) flows to the throttling element in the throttling heat exchanger (9) through the remote pipeline (8) to realize throttling refrigeration and directly contact with an object (10) to be cooled to realize heat exchange, so that remote throttling refrigeration is realized. The direct current loop module comprises a direct current pipeline (21) and a direct current control assembly; the two ends of the direct current pipeline (21) are respectively connected with the throttling element in the throttling heat exchanger (9) and the high-pressure pipeline of the refrigeration compressor device (1); a part of the direct current pipeline (21) directly contacts the radiation screen (6) and the cold finger (4) to realize heat back cooling of the radiation screen (6) and the cold finger (4) by using direct current; the flow is controlled through the direct current control assembly; and finally the direct current directly returns to the high-pressure pipeline of the refrigeration compressor device (1) to complete external circulation.

2. The regenerative refrigerator system according to claim 1, wherein, The direct current control assembly comprises a butterfly valve (7) arranged on the remote pipeline (8) and a first needle valve (11) and a first pressure sensor (12) arranged on the direct current pipeline (21).

3. The regenerative refrigerator system of claim 1, wherein, A part of the direct current pipeline (21) is wound on the outer wall of the radiation screen (6) and the first-stage cold end outer wall of the cold finger (4).

4. The regenerative refrigerator system of claim 1, wherein, The heat regenerative refrigeration module is one of a GM refrigeration machine, a GM type pulse tube refrigeration machine, a Stirling refrigeration machine, a Stirling type pulse tube refrigeration machine and a VM refrigeration machine.

5. The regenerative refrigerator system of claim 4, wherein, The heat regenerative refrigeration module is coaxial type, U type or linear type, has single-stage, two-stage or multi-stage refrigeration stages and has a thermal coupling structure or a gas coupling structure.

6. The regenerative refrigerator system of claim 1, wherein, The throttling element in the throttling heat exchanger (9) is in the form of a capillary tube or a throttling hole and has one or more than one.

7. The regenerative refrigerator system of claim 1, wherein, The refrigeration compressor device (1) is further provided with a low-pressure gas inlet pressure gauge (23), a high-pressure gas outlet pressure gauge (24), a compressor display screen (25) and a compressor control panel (26).

8. The regenerative refrigerator system of claim 1, wherein, The gas supplement inlet (22) is connected with a helium tank (18) through a helium pipeline; and the helium pipeline is provided with a second needle valve (15), a second pressure sensor (16) and a pressure reducing valve (17).

9. A remote throttling refrigeration method characterized by, The heat regenerative refrigeration machine system is used to perform the following specific process: Gaseous working medium with working pressure is filled into the heat regenerative refrigeration module to ensure that the internal pressure is 0.3-2.5 MPa; the frequency of the refrigeration compressor device (1) is adjusted; and the refrigeration compressor device (1) is started to start cooling. When the cold end heat exchanger (5) of the cold finger (4) is stabilized at 3-10K, the butterfly valve (7) and the first needle valve (11) in the direct current control assembly are opened in sequence, so that the direct current circulation starts to work, and when the temperature of the throttling heat exchanger (9) is stable, the corresponding refrigeration temperature and refrigeration capacity are obtained at the throttling heat exchanger (9).

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