Regenerative refrigerator system and method for leading out cold end direct current to achieve remote cooling

Abstract

The invention discloses a regenerative refrigerating machine system and method for achieving remote cooling by leading out cold end direct current. The regenerative refrigerating machine system comprises a regenerative refrigerating module, a remote throttling refrigerating 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, and high-voltage direct-current gas led out of the cold-end heat exchanger flows to a throttling element in the throttling heat exchanger through the remote pipeline and is in direct contact with an object to be cooled for heat exchange; the direct-current loop module comprises a direct-current pipeline, a part of the direct-current pipeline is in direct contact with the radiation screen and the cold finger, the radiation screen and the cold finger are cooled back through direct-current cooling capacity, the flow is controlled through the direct-current control assembly, and finally direct current directly returns to a high-pressure pipeline of the refrigerating machine compression device to complete external circulation. On the basis that the original refrigerating performance of the refrigerating machine is not reduced, the direct current is led out from the cold end, and remote cooling is achieved.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and in particular to a regenerative refrigerator system and method for extracting cold-end direct current to realize remote cooling. Background Art

[0002] Regenerative cryogenic refrigerators, such as pulse tube refrigerators, Stirling refrigerators, and GM refrigerators, are widely used in cryogenic technology fields such as low-temperature superconductivity and natural gas liquefaction due to their simple structure, high reliability, and high flexibility.

[0003] Currently, many occasions 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 at military bases, and imaging diagnosis centers at medical centers. However, the traditional regenerative refrigerator cannot directly provide remote cooling. Usually, an intermediate circulating refrigerant is required to transfer the cold from the cold end of the refrigerator to the cooled object, such as low-temperature helium circulation or heat pipe circulation. Both methods have certain shortcomings. For example, in the case of helium circulation, an additional low-temperature helium pump is required to realize the flow of helium, which increases 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 to the cooled object. This indirect method also increases the overall heat transfer resistance. Although heat pipes are beneficial to reducing the long-distance heat transfer resistance, their design and manufacturing are complex, and their heat transfer temperature is limited by the phase change temperature of the working fluid, making it difficult to achieve cold transfer at different temperatures. Therefore, how to optimize and transform the existing regenerative refrigerator to achieve its remote direct cooling has important application value.

[0004] In traditional regenerative refrigerators, there is only alternating current and no direct current flow. In early studies, direct current has always been considered to be the reason for deteriorating refrigerator performance, so researchers have made many efforts to suppress direct current. As the research deepens, experiments have found that within a certain size or direction, a certain amount of direct current flow is allowed inside the regenerative refrigerator, and direct current flow can also improve the performance of the refrigerator in the liquid helium temperature range.

[0005] For example, a Chinese patent document with publication number CN118089263A discloses a high-efficiency regenerative refrigeration system, which adopts cold-end direct current technology. The direct current fluid drawn from the regenerative cold-end heat exchanger of the cold finger will be throttled and heat-exchanged in the throttling cold-end heat exchanger, and then enter the direct current pipeline. The direct current pipeline contacts the copper ferrule heat exchanger fixed on the cold finger, and the cold energy generated by the direct current is used to recool the cold finger. However, this patent does not realize the remote cooling function, and the cryogenic pump installed on its direct current loop increases the energy consumption of the overall system.

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

[0007] The present invention provides a regenerative refrigerator system and method for extracting cold-end direct current to realize remote cooling, which can realize remote cooling by extracting a direct current from the cold end without reducing the original cooling performance of the refrigerator.

[0008] A regenerative refrigeration system for extracting cold-end direct current to realize remote cooling, 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, wherein the refrigerator compression device is provided with a low-pressure air inlet, a high-pressure air inlet and an air supply port, which are respectively connected to 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 provided in the low-pressure pipeline and the high-pressure pipeline, and the two pipelines are connected to the cold finger through a transmission pipeline after merging;

[0010] The remote throttling refrigeration module comprises a remote pipeline and a throttling heat exchanger, wherein the two ends of the remote pipeline are respectively connected to the cold end heat exchanger of the cold finger and the throttling element in the throttling heat exchanger; the high-pressure direct current gas drawn 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 for heat exchange, thereby realizing remote throttling refrigeration;

[0011] The DC loop module includes a DC pipeline and a DC control component. The two ends of the DC pipeline are respectively connected to the throttling element in the throttling heat exchanger and the high-pressure pipeline of the refrigerator compression device; a part of the DC pipeline directly contacts the radiation screen and the cold finger, and the cooling capacity of the DC is used to cool the radiation screen and the cold finger. The flow is controlled by the DC control component, and finally the DC directly returns to the high-pressure pipeline of the refrigerator compression device to complete the external circulation.

[0012] Furthermore, the DC control component includes a butterfly valve arranged on the remote pipeline and a No. 1 needle valve and a No. 1 pressure sensor arranged on the DC pipeline.

[0013] Furthermore, a portion of the DC pipeline is wound around the outer wall of the radiation screen and the outer wall of the primary 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 structure of the regenerative refrigeration module is coaxial, U-shaped or linear, the number of refrigeration stages is single-stage, two-stage or multi-stage, and the coupling structure is thermal coupling or gas coupling.

[0016] Optionally, the throttling element inside the throttling heat exchanger is in the form of a capillary tube or a throttling hole, and the number of the capillary tube or the throttling hole is one or more.

[0017] Furthermore, the refrigeration machine compression device is also provided with a low-pressure intake pressure gauge, a high-pressure exhaust pressure gauge, a compression device display screen and a compression device control panel.

[0018] Furthermore, the gas replenishing port is connected to the helium tank through a helium pipeline, and a No. 2 needle valve, a No. 2 pressure sensor and a pressure reducing valve are arranged on the helium pipeline.

[0019] A remote throttling refrigeration method adopts the above-mentioned high-efficiency heat recovery refrigerator system, and the specific process is as follows:

[0020] Fill the regenerative refrigeration module with gaseous working medium at working pressure to ensure that the internal pressure is within the range of 0.3-2.5 MPa, adjust the frequency of the compressor of the refrigerator, and start the compressor of the refrigerator to start cooling;

[0021] When the temperature of the cold end heat exchanger of the cold finger is stable at 3-10K, open the butterfly valve and No. 1 needle valve in the DC control component in sequence to start the DC cycle. When the temperature of the throttling heat exchanger is stable, the corresponding cooling temperature and cooling capacity are obtained at the throttling heat exchanger.

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

[0023] 1. Compared with the traditional heat recovery refrigerator system, the object to be cooled must extract cold through refrigerant heat exchange, which is indirect heat exchange and has a large thermal resistance. The present invention uses a throttling heat exchanger to enable the object to be cooled to extract cold from the refrigerator by direct contact, thereby reducing heat exchange thermal resistance and loss, which is beneficial to improving refrigeration performance.

[0024] 2. The present invention achieves remote refrigeration by throttling the derived direct current at a remote heat exchanger, thereby broadening the application scenarios and scope of the refrigerator.

[0025] 3. The present invention transfers the cold end direct current through the radiation screen outer wall heat exchange component and the cylinder outer wall heat exchange component to the regenerator for cooling and then passes it into the compressor, thereby strengthening the heat exchange, reducing the total heat loss of the regenerator by utilizing the direct current cooling capacity, and further improving the performance of the refrigerator.

[0026] 4. Compared with the existing heat recovery refrigerator system using cold-end direct current, the present invention does not use a cryogenic pump and directly passes the direct current back to the refrigerator high-pressure pipeline, saving energy and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The curves showing the change of 4.2K refrigeration performance and DC flow rate when using different DC tubes.

[0028] Figure 2 The present invention is a schematic diagram of the structure of a regenerative refrigerator system that extracts cold-end direct current to realize remote cooling.

[0029] Figure 3 Schematic diagram of the throttling heat exchanger structure used.

[0030] Figure 4 It is a schematic diagram of the structure of the radiation screen outer wall heat exchange component and the first-level cold end outer wall heat exchange component.

[0031] In the figure: 1-refrigeration machine compression device; 2-low-pressure air inlet; 3-high-pressure air inlet; 4-cold finger; 5-cold end heat exchanger; 6-radiation screen; 7-butterfly valve; 8-remote pipeline; 9-throttling heat exchanger; 10-object to be cooled; 11-No. 1 needle valve; 12-No. 1 pressure sensor; 13-radiation screen outer wall heat exchange component; 14-first-stage cold end outer wall heat exchange component; 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 supply port; 23-low-pressure inlet pressure gauge; 24-high-pressure exhaust pressure gauge; 25; compression device display screen; 26-compression device control panel. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0033] Theoretically, 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] in, is the pressure enthalpy flow caused by the real gas effect, is the heat enthalpy flow caused by irreversible heat exchange, is the heat conduction term of the regenerator.

[0036] Ignoring the shuttle loss and the heat conduction loss of the cylinder wall and the ejector wall, the cooling capacity of the cold end can be expressed as:

[0037]

[0038] in, is the acoustic power at the cold end.

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

[0040]

[0041] in, is the enthalpy flow induced by direct current.

[0042] Ignoring the shuttle loss and the heat conduction loss of the cylinder wall and the ejector wall, the cooling capacity of the cold end can be expressed as:

[0043]

[0044] Compared to the case without direct current, the presence of direct current in the regenerator changes the energy flow inside it because the enthalpy flow induced by the direct current is increased. In order to maintain energy balance, the pressure enthalpy flow in the regenerator Thermal enthalpy flow caused by irreversible heat exchange decreases, and the total energy flow The change is small. From a theoretical analysis, introducing a direct current into a regenerative refrigerator system will not have a negative impact on the overall cooling capacity of the refrigerator. Based on this theoretical derivation, the applicant conducted an experimental verification at a refrigeration temperature of 4.2K, led a direct current from the cold end of the regenerator, and monitored the corresponding changes in refrigerator performance as the direct current flow rate changed.

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

[0046] The heat recovery refrigeration module includes a refrigerator compression device 1, a low-pressure air inlet 2, a high-pressure air inlet 3, an air supply port 22, a low-pressure air distribution valve 19, a high-pressure air distribution valve 20, a low-pressure air inlet pressure gauge 23, a high-pressure exhaust 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 air inlet 2, the high-pressure air inlet 3 and the helium air inlet gas supply port 22 are respectively connected to the low-pressure pipeline, the high-pressure pipeline and the helium pipeline; a low-pressure gas distribution valve 19 and a high-pressure gas distribution valve 20 are respectively arranged in the low-pressure pipeline and the high-pressure pipeline, and the two pipelines are connected to the cold finger 4 through the transmission pipeline after merging.

[0048] The gas supply port 22 is connected to the helium tank 18 through a helium pipeline, and a No. 2 needle valve 15, a No. 2 pressure sensor 16 and a pressure reducing valve 17 are arranged on the helium pipeline.

[0049] The remote throttling refrigeration module includes a remote pipeline 8 and a throttling heat exchanger 9. The two ends of the remote pipeline 8 are respectively connected to the cold end heat exchanger 5 of the cold finger 4 and the throttling element in the throttling heat exchanger 9; the high-pressure direct current gas drawn 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 with the object to be cooled 10 for heat exchange, thereby realizing remote throttling refrigeration.

[0050] The DC circuit module includes a DC pipeline 21, a butterfly valve 7, a No. 1 needle valve 11, a No. 1 pressure sensor 12, a radiation screen outer wall heat exchange component 13, and a first-stage cold end outer wall heat exchange component 14. The two ends of the DC pipeline 21 are respectively connected to the throttling element in the throttling heat exchanger 9 and the high-pressure pipeline of the refrigerator compression device 1; the radiation screen outer wall heat exchange component 13 and the first-stage cold end outer wall heat exchange component 14 in the DC pipeline 21 directly contact the radiation screen 6 and the cold finger 4, and use the cold capacity of the DC to return the radiation screen 6 and the cold finger 4 to cool, and control the flow through the DC control component, and finally the DC directly returns to the high-pressure pipeline of the refrigerator compression device 1 to complete the external circulation.

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

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

[0053] However, the existing method of using direct current to improve the performance of the regenerative cryogenic refrigerator system still has shortcomings. The shortcomings 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 resistance is large; it is impossible to achieve long-distance cooling, and the applicable scenarios are limited; the direct current needs to be boosted by a cryogenic pump and then transported back to the pipeline, which increases energy consumption.

[0054] The present invention realizes remote cooling by extracting direct current from the cold end of the regenerator, and supplies cooling by direct contact between the object to be cooled and the throttling heat exchanger. Compared with the traditional cooling method, it reduces the heat exchange resistance and heat exchange loss. By using a throttling heat exchanger at the cold end, the present invention can realize the cooling of the radiation screen and the cold finger without increasing the additional operating cost, and fully utilize the intermediate cooling power of the regenerator. In addition, the direct current extracted from the cold end does not require the operation of an additional cryogenic pump, so that the helium returns to the high-pressure pipeline to complete the external circulation, saving energy consumption, thereby improving the performance of the refrigerator as a whole.

[0055] The working process of this embodiment is:

[0056] The system is installed as per the above process and requirements. After installation, evacuate the system components and pipelines to 10 -1 Then open the pressure reducing valve 17 and the second needle valve 15 to charge the gas working medium, keep it for about 5 minutes and then evacuate to 10 -1 Pa. After repeating this process 3 to 4 times, the gaseous working medium at the working pressure is finally filled into the regenerative refrigerator to ensure that the internal pressure is within the range of 0.3 to 2.5 MPa, thereby ensuring the purity of the working medium in the system. The refrigerator is driven by a compressor motor, and its rotary valve and discharger operate at a certain frequency. When starting, first adjust the compressor frequency through the compression device control panel 26, then turn on the power supply of the refrigerator compression device 1, and the refrigerator begins to cool down. When the temperature of the cold end heat exchanger 5 of the cold finger 4 is stable at 3 to 10K, open the butterfly valve 7 and the No. 1 needle valve 11 in sequence to start the direct current cycle, so that the system works normally until the temperature of the cold end heat exchanger 5 and the throttling heat exchanger 9 of the regenerative refrigerator is stable, and the corresponding refrigeration temperature and refrigeration capacity can be obtained at the cold end heat exchanger 5 and the throttling heat exchanger 9. After the heat exchange is completed, the helium will cool the radiation screen and the outer wall of the first cold end, making full use of its excess cold capacity to further improve the overall performance of the regenerative refrigerator, and finally return to the high-pressure pipeline to complete the external cycle.

[0057] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A regenerative refrigeration system for extracting cold-end direct current to realize remote cooling, characterized in that: It includes a heat recovery refrigeration module, a remote throttling refrigeration module and a DC loop module; The regenerative refrigeration module comprises a refrigerator compression device (1), a cold finger (4) and a radiation screen (6) which are connected in sequence. The refrigerator compression device (1) is provided with a low-pressure air inlet (2), a high-pressure air inlet (3) and an air supply port (22), which are respectively connected to 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 respectively provided in the low-pressure pipeline and the high-pressure pipeline, and the two pipelines are connected to the cold finger (4) through a transmission pipeline after merging; The remote throttling refrigeration module comprises a remote pipeline (8) and a throttling heat exchanger (9), wherein the two ends of the remote pipeline (8) are respectively connected to the cold end heat exchanger (5) of the cold finger (4) and the throttling element in the throttling heat exchanger (9); the high-pressure direct current gas drawn 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 with the object to be cooled (10) to perform heat exchange, thereby realizing remote throttling refrigeration; The DC loop module comprises a DC pipeline (21) and a DC control component. The two ends of the DC pipeline (21) are respectively connected to the throttling element in the throttling heat exchanger (9) and the high-pressure pipeline of the refrigeration machine compression device (1). A portion of the DC pipeline (21) directly contacts the radiation screen (6) and the cold finger (4). The cooling capacity of the DC is used to return the cooling to the radiation screen (6) and the cold finger (4). The flow rate is controlled by the DC control component. Finally, the DC directly returns to the high-pressure pipeline of the refrigeration machine compression device (1) to complete the external circulation.

2. The regenerative refrigerator system for realizing remote cooling by extracting cold-end direct current according to claim 1 is characterized in that: The direct current control component comprises a butterfly valve (7) arranged on a remote pipeline (8) and a No. 1 needle valve (11) and a No. 1 pressure sensor (12) arranged on a direct current pipeline (21).

3. The regenerative refrigerator system for realizing remote cooling by extracting cold-end direct current according to claim 1 is characterized in that: A portion of the direct current pipeline (21) is wound around the outer wall of the radiation screen (6) and the outer wall of the primary cold end of the cold finger (4).

4. The regenerative refrigeration system for realizing remote cooling by extracting cold-end direct current according to claim 1, characterized in that: 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.

5. The regenerative refrigerator system for realizing remote cooling by extracting cold-end direct current according to claim 4 is characterized in that: The structure of the regenerative refrigeration module is coaxial, U-shaped or linear, the number of refrigeration stages is single-stage, two-stage or multi-stage, and the coupling structure is thermal coupling or gas coupling.

6. The regenerative refrigerator system for realizing remote cooling by extracting cold-end direct current according to claim 1 is characterized in that: The throttling element inside the throttling heat exchanger (9) is in the form of a capillary tube or a throttling hole, and the number of the throttling element is one or more.

7. The regenerative refrigerator system for realizing remote cooling by extracting cold-end direct current according to claim 1, characterized in that: The refrigeration machine compression device (1) is also provided with a low-pressure intake pressure gauge (23), a high-pressure exhaust pressure gauge (24), a compression device display screen (25) and a compression device control panel (26).

8. The regenerative refrigerator system for realizing remote cooling by extracting cold-end direct current according to claim 1, characterized in that: The gas replenishing port (22) is connected to the helium tank (18) via a helium pipeline, and the helium pipeline is provided with a No. 2 needle valve (15), a No. 2 pressure sensor (16) and a pressure reducing valve (17).

9. A remote throttling refrigeration method, characterized in that: The high-efficiency regenerative refrigerator system according to any one of claims 1 to 7 is used, and the specific process is as follows: Filling the regenerative refrigeration module with a gaseous working medium at a working pressure to ensure that the internal pressure is between 0.3 and 2.5 MPa, adjusting the frequency of the refrigeration machine compression device (1), and starting the refrigeration machine compression device (1) to start cooling; When the temperature of the cold end heat exchanger (5) of the cold finger (4) is stabilized at 3 to 10K, the butterfly valve (7) and the No. 1 needle valve (11) in the DC control component are opened in sequence to start the DC cycle. When the temperature of the throttling heat exchanger (9) is stabilized, the corresponding refrigeration temperature and refrigeration capacity are obtained at the throttling heat exchanger (9).

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