Refrigeration system and method

Abstract

The present application relates to the technical field of refrigeration and low temperature engineering, and provides a kind of refrigeration system and method, by the connection of precooling stage refrigerator and adsorption refrigerator is improved, first cold output thermal bridge is connected between cold head and condensing evaporation end, second cold output thermal bridge is connected between cold accumulator and adsorption pump.In condensing phase, the cold of precooling stage refrigerator cold head is guided to the condensing evaporation end of adsorption refrigerator through first cold output thermal bridge, so as to effectively reduce the temperature of condensing evaporation end, improve condensing effect;In evaporation phase, the cold of precooling stage refrigerator cold accumulator is guided to the adsorption pump of adsorption refrigerator through second cold output thermal bridge, so as to provide sufficient cold for adsorption pump.The whole process can significantly reduce the cold demand of adsorption refrigerator on the cold head of precooling stage refrigerator, and then improve the refrigeration efficiency, achieve the purpose of cryogenic refrigeration.

Description

Technical Field

[0001] This invention relates to the field of refrigeration and cryogenic engineering technology, and in particular to a refrigeration system and method. Background Technology

[0002] Helium adsorption cryostats are one of the important refrigeration technologies for obtaining mK temperatures. They typically require liquid helium or GM-type cryogenic cryostats to provide pre-cooling temperatures below 4K. Traditional cryogenic cryostats have significant shortcomings in terms of lifespan, weight, and power consumption, which limits their application in some ground-based cryogenic experiments, especially in space applications where weight and power consumption requirements are stringent.

[0003] Replacing the aforementioned precooling method with a lightweight 4K refrigerator is an important development direction for adsorption refrigerators. The "multi-stage Stirling refrigerator / high-frequency pulse tube refrigerator + stoichiometric refrigerator" composite refrigeration system and the high-frequency pulse tube refrigerator are important lightweight refrigeration methods capable of achieving temperatures below 4K, but currently their cooling capacity is very small (especially the high-frequency pulse tube refrigerator, whose 4K cooling capacity is only a few milliwatts). In existing technologies, the entire adsorption refrigerator is directly coupled to a liquid helium Dewar or the 4K cold head of the precooling stage refrigerator. When the refrigerator is used as the precooling stage, and the precooling capacity of the precooling stage is insufficient, the cooling temperature of the precooling stage is difficult to reach the liquid helium temperature range required by the low-temperature adsorption refrigerator, thus making it difficult or impossible for the low-temperature adsorption refrigerator to reach the set temperature; or when the cooling capacity is greater than the system's heat loss, even if the refrigeration system can reach the set temperature, its cooling rate is extremely slow. Summary of the Invention

[0004] This invention provides a refrigeration system and method to solve the defects in the prior art where the precooling capacity is insufficient when using lightweight refrigerators such as high-frequency pulse tubes as the precooling stage of mK adsorption refrigerators, resulting in the refrigeration system being unable or even unable to reach the set temperature or cooling down extremely slowly. This invention reduces the cooling capacity requirement of the adsorption refrigerator on the 4K cold head and improves the cooling effect.

[0005] This invention provides a refrigeration system, comprising:

[0006] A pre-cooling stage refrigerator has a hot end and a cold head, and a cold accumulator connecting the hot end and the cold end;

[0007] An adsorption refrigeration unit has an adsorption pump and a condenser-evaporator end, as well as a pump pipe connecting the adsorption pump and the condenser-evaporator end;

[0008] The first cooling output thermal bridge is connected at one end to the cold head and at the other end to the condenser-evaporator end.

[0009] The second cold output thermal bridge is connected at one end to the cold accumulator and at the other end to the adsorption pump.

[0010] According to one embodiment of the present invention, the connection position of the second cold output thermal bridge on the cold accumulator is adjustable relative to the hot end.

[0011] According to one embodiment of the present invention, it further includes:

[0012] The third cold output thermal bridge is connected at one end to the cold accumulator and at the other end to the pump pipe.

[0013] The connection point of the third cold output thermal bridge on the cold storage unit is located between the connection point of the second cold output thermal bridge on the cold storage unit and the hot end.

[0014] According to one embodiment of the present invention, the connection position of the third cold output thermal bridge on the cold storage device is adjustable relative to the hot end.

[0015] According to one embodiment of the present invention, the third cooling output heat bridge includes a third heat bridge body and a third thermal switch, wherein the third thermal switch is connected between the third heat bridge body and the pump tube.

[0016] According to one embodiment of the present invention, the first cooling output heat bridge includes a first heat bridge body and a first heat switch, wherein the first heat switch is connected between the first heat bridge body and the condensation and evaporation end;

[0017] The second cooling output heat bridge includes a second heat bridge body and a second thermal switch, with the second thermal switch connected between the second heat bridge body and the adsorption pump.

[0018] According to one embodiment of the present invention, the second cooling output thermal bridge further includes a fourth thermal switch, which is connected between the second thermal bridge body and the pump tube.

[0019] According to one embodiment of the present invention, the connection between the first cold output thermal bridge and the cold head, and the connection between the second cold output thermal bridge and the cold accumulator, are made by screws, welding, bonding, or integral molding.

[0020] According to one embodiment of the present invention, the adsorption refrigeration machine further includes an adsorption pump heater, which is disposed on the adsorption pump.

[0021] The present invention also provides a refrigeration method, comprising:

[0022] During the condensation stage, the cooling capacity of the cold head of the precooling stage refrigerator is directed to the condensation and evaporation end of the adsorption refrigerator through a thermal bridge;

[0023] During the evaporation stage, the cooling capacity of the precooling stage refrigerator's accumulator is directed to the adsorption pump of the adsorption refrigerator via a thermal bridge.

[0024] The refrigeration system and method provided by this invention uses a lightweight refrigerator, such as a high-frequency pulse tube, as the pre-cooling stage refrigerator of an mK adsorption refrigerator. The pre-cooling stage refrigerator has a hot end, a cold head, and a cold accumulator connecting the hot end and the cold end. The adsorption refrigerator has an adsorption pump, a condenser-evaporator end, and a pump pipe connecting the adsorption pump and the condenser-evaporator end. By improving the connection between the pre-cooling stage refrigerator and the adsorption refrigerator, a first cold output heat bridge is connected between the cold head and the condenser-evaporator end, and a second cold output heat bridge is connected between the cold accumulator and the adsorption pump. In the condensation stage, the cold energy from the cold head of the pre-cooling stage refrigerator is directed to the condenser-evaporator end of the adsorption refrigerator through the first cold output heat bridge, thereby effectively reducing the temperature of the condenser-evaporator end and improving the condensation effect. In the evaporation stage, the cold energy from the cold accumulator of the pre-cooling stage refrigerator is directed to the adsorption pump of the adsorption refrigerator through the second cold output heat bridge, thereby providing sufficient cold energy for the adsorption pump. The entire process can significantly reduce the cold energy requirement of the adsorption refrigerator on the cold head of the pre-cooling stage refrigerator, thereby improving the refrigeration efficiency and achieving the purpose of extremely low temperature refrigeration.

[0025] This invention effectively solves the problem that when the precooling capacity of the precooling stage is insufficient, the refrigeration temperature of the precooling stage is difficult to reach the liquid helium temperature range required by the low-temperature adsorption refrigeration finger, thus making it difficult or even impossible for the temperature of the low-temperature adsorption refrigeration machine to reach the set temperature. By directing the cooling capacity of different locations in the precooling stage refrigeration machine to different areas of the adsorption refrigeration machine that need to be cooled, the cooling capacity is effectively utilized, the cooling capacity requirement of the adsorption pump of the adsorption refrigeration machine on the cold head of the precooling stage refrigeration machine is reduced, thereby improving the refrigeration efficiency of the system and realizing lightweight ultra-low temperature refrigeration. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the first embodiment of the refrigeration system provided by the present invention;

[0028] Figure 2 This is a schematic diagram of the second embodiment of the refrigeration system provided by the present invention;

[0029] Figure 3 This is a schematic diagram of the third embodiment of the refrigeration system provided by the present invention;

[0030] Figure 4This is a flowchart of the refrigeration method steps provided by the present invention.

[0031] Figure label:

[0032] 10: Pre-cooling stage refrigerator; 11: Hot end; 12: Cold accumulator; 13: Cold head; 20: First heat bridge body; 30: Adsorption refrigerator; 31: Adsorption pump; 32: Pump pipe; 33: Condensation and evaporation end; 34: Adsorption pump heater; 40: First thermal switch; 41: Cold end of first thermal switch; 42: Connector of first thermal switch; 43: Hot end of first thermal switch; 50: Second thermal switch; 51: Hot end of second thermal switch; 52: Connector of second thermal switch; 53: Cold end of second thermal switch; 60: Second heat bridge body; 70: Third thermal switch; 71: Hot end of third thermal switch; 72: Connector of third thermal switch; 73: Cold end of third thermal switch; 80: Third heat bridge body; 90: Fourth thermal switch; 91: Hot end of fourth thermal switch; 92: Connector of fourth thermal switch; 93: Cold end of fourth thermal switch. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0036] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] Please see Figures 1-3 This invention provides a refrigeration system that uses a lightweight refrigerator such as a high-frequency pulse tube as a pre-cooling stage of an mK adsorption refrigerator. The pre-cooling stage refrigerator provides sufficient cooling capacity to the adsorption refrigerator, thereby effectively obtaining the specified mK temperature and achieving lightweight 4K refrigeration.

[0039] like Figure 1-3 As shown, the embodiments of the present invention mainly include a pre-cooling stage refrigerator 10 and an adsorption refrigerator 30.

[0040] The precooling stage refrigerator 10 has a precooling stage refrigerator hot end 11, a precooling stage refrigerator cold head 13 and a precooling stage refrigerator cold accumulator 12, wherein the precooling stage refrigerator cold accumulator 12 connects the precooling stage refrigerator hot end 11 and the precooling stage refrigerator cold head 13, and the temperature of the precooling stage refrigerator cold accumulator 12 gradually decreases from the precooling stage refrigerator hot end 11 to the precooling stage refrigerator cold head 13.

[0041] The adsorption refrigeration unit 30 has an adsorption pump 31, a condenser-evaporator end 33 and a pump pipe 32. The adsorption pump 31 is connected to the condenser-evaporator end 33 through the pump pipe 32. The condenser-evaporator end 33 is the condenser-evaporator chamber. The pump pipe 32 is connected to the condenser-evaporator chamber and is used to transport refrigerant.

[0042] In some embodiments, the adsorption refrigerator 30 is a helium adsorption refrigerator to meet the cooling requirements of the 4K refrigerator. The precooling stage refrigerator 10 is a high-frequency pulse tube refrigerator so that the precooling stage refrigerator cold head 13 meets the requirements of the 4K cold head.

[0043] In this embodiment, a first cooling capacity output heat bridge and a second cooling capacity output heat bridge are also provided. One end of the first cooling capacity output heat bridge is connected to the cold head 13 of the pre-cooling stage refrigerator, and the other end is connected to the condenser-evaporator end 33. The first cooling capacity output heat bridge can direct the cooling capacity of the cold head 13 of the pre-cooling stage refrigerator to the condenser-evaporator end 33 of the adsorption refrigerator 30, thereby improving the condensation efficiency. One end of the second cooling capacity output heat bridge is connected to the cold storage accumulator 12 of the pre-cooling stage refrigerator, and the other end is connected to the adsorption pump 31 of the adsorption refrigerator 30. The second cooling capacity output heat bridge can direct the cooling capacity of the cold storage accumulator 12 of the pre-cooling stage refrigerator to the adsorption pump 31, thereby improving the evaporation efficiency, and thus continuously reducing the temperature of the condenser-evaporator end 33.

[0044] In this embodiment of the invention, a first thermal bridge for cold energy output is established between the cold head 13 of the pre-cooling stage refrigerator 10 and the condensing-evaporating end 33 of the adsorption refrigerator 30. During the condensation stage, this first thermal bridge directs the cold energy from the cold head 13 of the pre-cooling stage refrigerator 10 to the condensing-evaporating end 33 of the adsorption refrigerator 30, thereby effectively reducing the temperature of the condensing-evaporating end 33, improving the condensation effect, and achieving effective cooling. A second thermal bridge for cold energy output is established between the cold accumulator 12 of the pre-cooling stage refrigerator 10 and the adsorption pump 31 of the adsorption refrigerator 30. During the evaporation stage, this second thermal bridge directs the cold energy from the cold accumulator 12 of the pre-cooling stage refrigerator to the adsorption pump 31 of the adsorption refrigerator 30, thereby providing sufficient cold energy to the adsorption pump. The temperature of the adsorption pump 31 decreases, and it begins to continuously adsorb helium from the evaporating-condensing end 33. At this time, the gas phase pressure of liquid helium inside the condensing-evaporating end 33 gradually decreases, leading to a continuous decrease in temperature, thus achieving ultra-low temperature refrigeration. The entire process can significantly reduce the cooling capacity requirement of the adsorption refrigeration unit 30 on the pre-cooling stage refrigeration unit cold head 13, thereby improving the refrigeration efficiency and achieving the purpose of extremely low temperature refrigeration.

[0045] This system effectively solves the problem that when the precooling capacity of the precooling stage is insufficient, the refrigeration temperature of the precooling stage is difficult to reach the liquid helium temperature range required by the low-temperature adsorption refrigeration index, which in turn makes it difficult or even impossible for the low-temperature adsorption refrigeration machine to reach the set temperature. It also effectively improves the cooling speed and refrigeration efficiency.

[0046] like Figure 1 As shown, the present invention provides a first embodiment, wherein the first cold output heat bridge includes a first heat bridge body 20 and a first heat switch 40. The first heat switch 40 is connected between the first heat bridge body 20 and the condensation and evaporation end 33, and the first heat switch 40 is used to realize the switching of the cold output of the first cold output heat bridge.

[0047] Specifically, the first thermal switch 40 also includes a first thermal switch connector 42, a first thermal switch cold end 41, and a first thermal switch hot end 43. The first thermal switch cold end 41 is connected between the first thermal bridge body 20 and the first thermal switch connector 42, and the first thermal switch hot end 43 is connected between the condensation and evaporation end 33 and the first thermal switch connector 42.

[0048] The second cold output thermal bridge includes a second thermal bridge body 60 and a second thermal switch 50. The second thermal switch 50 is connected between the second thermal bridge body 60 and the adsorption pump 31. The second thermal switch 50 is used to switch the cold output of the second cold output thermal bridge.

[0049] Specifically, the second thermal switch 50 includes a second thermal switch connector 52, a second thermal switch cold end 53, and a second thermal switch hot end 51. The second thermal switch cold end 53 is connected between the second thermal bridge body 60 and the second thermal switch connector 52, and the second thermal switch hot end 51 is connected between the adsorption pump 31 and the second thermal switch connector 52.

[0050] In one embodiment, the first thermal switch 40 and the second thermal switch 50 can be thermal resistance switches. When the thermal resistance is high, the switch is in the closed state; when the thermal resistance is low, the switch is in the open state.

[0051] In this embodiment, the adsorption refrigeration unit 30 further includes an adsorption pump heater 34, which is disposed on the adsorption pump 31 and is used to heat the adsorption pump 31.

[0052] The working principle of the first embodiment provided by the present invention is as follows:

[0053] Condensation Stage: The pre-cooling stage refrigerator 10 is in the start-up state, the second thermal switch 50 is in the closed state (thermal resistance is at a high value), and the first thermal switch 40 is in the open state (thermal resistance is at a low value). The adsorption pump heater 34 is started, and the temperature of the adsorption pump 31 rises. The first cooling output thermal bridge continuously directs the cooling capacity of the cold head 13 of the pre-cooling stage refrigerator 10 to the evaporation-condensation end 33 of the adsorption refrigerator 30. The temperature of the evaporation-condensation end 33 decreases, and the adsorption pump 31 begins to continuously release the helium adsorbed in the previous stage. As the temperature of the evaporation-condensation end 33 continues to decrease, the helium released from the adsorption pump 31 continuously condenses into liquid inside the evaporation-condensation end 33. This process continues until the helium inside the adsorption refrigerator 30 can no longer be condensed.

[0054] Evaporation Stage: The precooling stage refrigerator 10 is in the start-up state, the second thermal switch 50 is in the open state (thermal resistance is at a low value), the first thermal switch 40 is in the closed state (thermal resistance is at a high value), and the adsorption pump heater 34 is turned off. Simultaneously, the second cold output thermal bridge continuously directs the cold energy from the cold storage 12 of the precooling stage refrigerator 10 to the adsorption pump 31 of the adsorption refrigerator 30. The temperature of the adsorption pump 31 decreases, and it begins to continuously adsorb helium from the evaporation-condensation end 33. At this time, the gas phase pressure of liquid helium inside the evaporation-condensation end 33 gradually decreases, causing the temperature to continuously decrease, thereby achieving extremely low temperature refrigeration. This process continues until all the liquid helium inside the evaporation-condensation end 33 is adsorbed by the adsorption pump 31.

[0055] like Figure 2 As shown, the present invention provides a second embodiment, which is the same as the first embodiment, but adds a third cold output thermal bridge based on the first embodiment.

[0056] One end of the third cold energy output heat bridge is connected to the cold storage 12, and the other end is connected to the pump tube 32 of the adsorption refrigeration machine 30. The third cold energy output heat bridge guides the cold energy of the cold storage 12 of the precooling stage refrigeration machine 10 to the pump tube 32 of the adsorption refrigeration machine 30, thereby reducing the temperature of the pump tube 32, which is beneficial to the condensation efficiency of the adsorption refrigeration machine 30.

[0057] Specifically, the third cooling output heat bridge includes a third heat bridge body 80 and a third heat switch 70, with the third heat switch 70 connected between the third heat bridge body 80 and the pump pipe 32. The third heat switch 70 also includes a hot end 71, a connector 72, and a cold end 73. The hot end 71 is connected between the connector 72 and the pump pipe 32, and the cold end 73 is connected between the connector 72 and the third heat bridge body 80.

[0058] It is worth mentioning that the connection position of the third cold energy output heat bridge on the cold storage 12 is located between the connection position of the second cold energy output heat bridge on the cold storage 12 and the hot end 11. That is, the connection position of the third cold energy output heat bridge on the cold storage 12 is closer to the hot end 11. This ensures that the quality of the cooling capacity supplied by the third cold energy output heat bridge is lower than that supplied by the second cold energy output heat bridge, which is beneficial to the adsorption operation of the adsorption pump 31, thereby improving the refrigeration performance and efficiency.

[0059] The working principle of the second embodiment provided by the present invention is as follows:

[0060] Condensation Stage: The pre-cooling stage refrigerator 10 is in the start-up state, the second thermal switch 50 is in the closed state (thermal resistance is high), the third thermal switch 70 is in the open state (thermal resistance is low), and the first thermal switch 40 is in the open state (thermal resistance is low). The adsorption pump heater 34 is started, the temperature of the adsorption pump 31 rises, and it begins to continuously release the helium adsorbed in the previous stage. The first cold output thermal bridge continuously directs the cold energy from the cold head 13 of the pre-cooling stage refrigerator 10 to the evaporator-condenser end 33 of the adsorption refrigerator 30, and the third cold output thermal bridge continuously directs the cold energy from the cold accumulator 12 of the pre-cooling stage refrigerator 10 to the pump tube 32 of the adsorption refrigerator 30. The temperature of the evaporator-condenser end 33 continuously decreases, and the helium released from the adsorption pump 31 continuously condenses into liquid inside the evaporator-condenser end 33. This process continues until the helium inside the adsorption refrigerator 30 can no longer be condensed.

[0061] Evaporation Stage: The precooling stage refrigerator 10 is in the start-up state, the second thermal switch 50 is in the open state (thermal resistance is at a low value), the third thermal switch 70 is in the closed state (thermal resistance is at a high or low value), the first thermal switch 40 is in the closed state (thermal resistance is at a high value), the adsorption pump heater 34 is turned off, the temperature of the adsorption pump 31 decreases, and at the same time, the second cold output thermal bridge continuously directs the cold energy from the cold storage 12 of the precooling stage refrigerator 10 to the adsorption pump 31 of the adsorption refrigerator 30. The temperature of the adsorption pump 31 further decreases, and it begins to continuously adsorb helium from the evaporation-condensation end 33. At this time, the gas phase pressure of liquid helium inside the evaporation-condensation end 33 gradually decreases, causing the temperature to continuously decrease, thereby achieving ultra-low temperature refrigeration. This process continues until all the liquid helium inside the evaporation-condensation end 33 is adsorbed by the adsorption pump 31.

[0062] This embodiment, by setting a third cooling output thermal bridge, can further enhance the cooling of the condensing evaporation end 33 during the condensation stage, improve the condensation effect, reduce the cooling demand of the adsorption refrigeration unit 30 on the cold head 13, effectively improve the cooling speed, and improve the refrigeration efficiency.

[0063] like Figure 3 As shown, the present invention provides a third embodiment, which is the same as the first embodiment, but improves the second cold output thermal bridge based on the first embodiment.

[0064] The second heat bridge body 60 of the second cooling output heat bridge is equipped with a second heat switch 50 and a fourth heat switch 90, which is connected between the second heat bridge body 60 and the pump pipe 32. When the fourth heat switch 90 is in the open state, it can provide cooling capacity to the pump pipe 32 of the adsorption refrigeration unit 30 to improve condensation efficiency.

[0065] Specifically, the fourth thermal switch 90 includes a hot end 91, a connector 92, and a cold end 93. The hot end 91 is connected between the pump pipe 32 and the connector 92, and the cold end 93 is connected between the second thermal bridge body 60 and the connector 92.

[0066] The working principle of the third embodiment provided by the present invention is as follows:

[0067] Condensation Stage: The pre-cooling stage refrigerator 10 is in the start-up state, the second thermal switch 50 is in the closed state (thermal resistance is high), the fourth thermal switch 90 is in the open state (thermal resistance is low), and the first thermal switch 40 is in the open state (thermal resistance is low). The adsorption pump heater 34 is started, the temperature of the adsorption pump 31 rises, and it begins to continuously release the helium adsorbed in the previous stage. The first cold output thermal bridge continuously directs the cold energy from the cold head 13 of the pre-cooling stage refrigerator 10 to the evaporator-condenser end 33 of the adsorption refrigerator 30. At the same time, the second cold output thermal bridge continuously directs the cold energy from the cold accumulator 12 of the pre-cooling stage refrigerator 10 to the pump tube 32 of the adsorption refrigerator 30. The temperature of the pump tube 32 and the evaporator-condenser end 33 continuously decreases, and the helium released from the adsorption pump 31 continuously condenses into liquid inside the evaporator-condenser end 33. This process continues until the helium inside the adsorption refrigerator 31 can no longer be condensed.

[0068] Evaporation Stage: The precooling stage refrigerator 10 is in the start-up state, the second thermal switch 50 is in the open state (thermal resistance is at a low value), the fourth thermal switch 90 is in the closed state (thermal resistance is at a high or low value), the first thermal switch 40 is in the closed state (thermal resistance is at a high value), and the adsorption pump heater 34 is turned off. Simultaneously, the second cold output thermal bridge continuously directs the cold energy from the cold storage 12 of the precooling stage refrigerator 10 to the adsorption pump 31 of the adsorption refrigerator 30. The temperature of the adsorption pump 31 decreases, and it begins to continuously adsorb helium from the evaporation-condensation end 33. At this time, the gas phase pressure of liquid helium inside the evaporation-condensation end 33 gradually decreases, causing the temperature to continuously decrease, thereby achieving extremely low temperature refrigeration. This process continues until all the liquid helium inside the evaporation-condensation end 33 is adsorbed by the adsorption pump 31.

[0069] In this embodiment, during the condensation stage, the first cold output thermal bridge directs the cold energy of the cold head 13 to the evaporation-condensation end 33, while the second cold output thermal bridge directs the cold energy of the cold storage unit 12 to the pump tube. This can reduce the temperature of the evaporation-condensation end 33 more quickly, accelerate helium condensation, improve condensation efficiency, and increase the cold energy of the evaporation-condensation end 33. Consequently, the demand of the adsorption refrigerator 30 on the cold head 13 is reduced, which is beneficial for ultra-low temperature refrigeration.

[0070] It is worth mentioning that, in this embodiment, since the second cold output heat bridge is connected to the cold storage 12, the cold output quality of the second cold output heat bridge is lower than that of the first cold output heat bridge. Therefore, the other end of the second cold output heat bridge is connected to the pump pipe 32, thereby making the temperature of the pump pipe 32 higher than that of the evaporation and condensation end 33, thus ensuring the condensation effect of the adsorption refrigeration unit 30.

[0071] Based on the above three embodiments, the second or third cold output heat bridge is connected to the cold storage 12. As a further improvement, in some embodiments, the connection position of the second or third cold output heat bridge on the cold storage 12 can be adjusted. That is, the connection position of the heat bridge on the cold storage 12 can be adjusted between the hot end 11 and the cold head 13. The cold storage 12 has different cold capacity depending on the distance from the hot end 11 or the cold head 13. Therefore, by adjusting the connection position of the heat bridge on the cold storage 12, the corresponding cold capacity of the heat bridge can be controlled, thereby providing appropriate cold capacity for the adsorption refrigeration machine 30, which helps to improve the working efficiency of the adsorption refrigeration machine 30 and enhance the refrigeration performance of the adsorption refrigeration machine 30.

[0072] In one embodiment, the connection between the first cold output heat bridge and the cold head 13, and between the second or third cold output heat bridge and the cold storage 12, can be achieved by screw connection, welding, or bonding. Of course, when their positions do not need to be adjusted, they can be integrally formed.

[0073] In one embodiment, the first, second, and third cold output heat bridges are made of a material with high thermal conductivity, such as copper strips.

[0074] like Figure 4 As shown, this embodiment of the invention also provides a refrigeration method, which includes the following steps:

[0075] Step 1: In the condensation stage, the cooling capacity of the cold head 13 of the pre-cooling stage refrigerator 10 is guided to the condensing and evaporating end 33 of the adsorption refrigerator 30 through the thermal bridge.

[0076] Specifically, a cooling output heat bridge can be established between the cold head 13 of the pre-cooling stage refrigerator 10 and the condenser-evaporator end 33 of the adsorption refrigerator 30. The heat bridge can be made of materials such as copper strips. This heat bridge continuously lowers the temperature of the evaporator-condenser end 33, causing the helium gas released from the adsorption pump 31 to continuously condense into liquid inside the evaporator-condenser end 33. During the condensation process, the evaporator-condenser end 33 absorbs the cooling capacity of the cold head 13, thereby reducing the cooling capacity requirement of the adsorption refrigerator 30 on the cold head 13 and improving the cooling effect.

[0077] Step 2: During the evaporation stage, the cooling capacity of the cold storage 12 of the precooling stage refrigerator 10 is directed to the adsorption pump 31 of the adsorption refrigerator 30 via a thermal bridge.

[0078] Specifically, a cooling output thermal bridge can be established between the cold storage accumulator 12 of the precooling stage refrigerator 10 and the adsorption pump 31 of the adsorption refrigerator 30. The thermal bridge causes the temperature of the adsorption pump 31 to continuously decrease, and it begins to continuously adsorb helium from the evaporation-condensation end 33. At this time, the gas phase pressure of liquid helium inside the condensation-evaporation end 33 gradually decreases, resulting in a continuous decrease in temperature, thereby achieving ultra-low temperature refrigeration.

[0079] The refrigeration system and method provided in this invention effectively solve the problem that when the precooling capacity of the precooling stage is insufficient, the refrigeration temperature of the precooling stage is difficult to reach the liquid helium temperature range required by the low-temperature adsorption refrigeration index, which in turn makes it difficult or even impossible for the temperature of the low-temperature adsorption refrigeration machine to reach the set temperature. By directing the cooling capacity of the precooling stage refrigeration machine 10 to different areas of the adsorption refrigeration machine 30 that need to be cooled, the cooling capacity is effectively utilized, the cooling capacity requirement of the adsorption pump 31 of the adsorption refrigeration machine 30 on the cold head 13 of the precooling stage refrigeration machine 10 is reduced, thereby improving the refrigeration efficiency of the system and realizing lightweight ultra-low temperature refrigeration.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A refrigeration system, characterized in that, include: The precooling stage refrigerator (10) has a hot end (11) and a cold head (13), and a cold accumulator (12) connecting the hot end (11) and the cold head (13). The adsorption chiller (30) has an adsorption pump (31) and a condenser-evaporator (33), and a pump pipe (32) connecting the adsorption pump (31) and the condenser-evaporator (33). The first cold output thermal bridge is connected at one end to the cold head (13) and at the other end to the condenser-evaporator end (33). The second cold output heat bridge is connected to the cold storage (12) at one end and to the adsorption pump (31) at the other end. The first cold output thermal bridge includes: a first thermal bridge body (20) and a first thermal switch (40); One end of the first thermal bridge body (20) is connected to the cold head (13), and the other end of the first thermal bridge body (20) extends toward the side facing the condensation and evaporation end (33); One end of the first thermal switch (40) is connected to the first thermal bridge body (20), and the other end of the first thermal switch (40) is connected to the condensation and evaporation end (33); The second cooling output heat bridge includes: a second heat bridge body (60) and a second thermal switch (50); One end of the second thermal bridge body (60) is connected to the cold storage (12), and the other end of the second thermal bridge body (60) extends toward the side facing the condensation and evaporation end (33); One end of the second thermal switch (50) is connected to the second thermal bridge body (60), and the other end of the second thermal switch (50) is connected to the adsorption pump (31); The connection between the first cold output heat bridge and the cold head (13), and the connection between the second cold output heat bridge and the cold accumulator (12) are made by screws, welding, bonding or integral molding; The adsorption refrigeration unit (30) further includes an adsorption pump heater (34), which is disposed on the adsorption pump (31).

2. The refrigeration system according to claim 1, characterized in that, The connection position of the second cold output thermal bridge on the cold storage unit (12) is adjustable relative to the hot end (11).

3. The refrigeration system according to claim 1, characterized in that, Also includes: The third cold output heat bridge is connected to the cold accumulator (12) at one end and to the pump pipe (32) at the other end. The connection position of the third cold output thermal bridge on the cold storage unit (12) is located between the connection position of the second cold output thermal bridge on the cold storage unit (12) and the hot end (11).

4. The refrigeration system according to claim 3, characterized in that, The connection position of the third cold output thermal bridge on the cold storage unit (12) is adjustable relative to the hot end (11).

5. The refrigeration system according to claim 3, characterized in that, The third cooling output thermal bridge includes: a third thermal bridge body (80) and a third thermal switch (70). One end of the third thermal bridge body (80) is connected to the cold storage unit (12), and the other end of the third thermal bridge body (80) extends toward the condenser-evaporator end (33). One end of the third thermal switch (70) is connected to the third thermal bridge body (80), and the other end of the third thermal switch (70) is connected to the pump pipe (32).

6. The refrigeration system according to claim 1, characterized in that, The second cooling output thermal bridge also includes: a fourth thermal switch (90); One end of the fourth thermal switch (90) is connected to the second thermal bridge body (60), and the other end of the fourth thermal switch (90) is connected to the pump pipe (32).

7. A refrigeration method for the refrigeration system according to any one of claims 1 to 6, characterized in that, include: During the condensation stage, the cooling capacity of the cold head (13) of the precooling stage refrigerator (10) is directed to the condensation and evaporation end (33) of the adsorption refrigerator (30) through a thermal bridge. During the evaporation stage, the cold energy of the cold storage unit (12) of the precooling stage refrigerator (10) is directed to the adsorption pump (31) of the adsorption refrigerator (30) through a thermal bridge.

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