Low-temperature refrigerating system, refrigerating method, defrosting method and low-temperature storage box

Abstract

The invention relates to a low-temperature refrigerating system, a refrigerating method, a defrosting method and a low-temperature storage box. According to the low-temperature refrigerating system, the space temperature gradient of the refrigerating environment can be reduced, the temperature in the refrigerating environment where the low-temperature refrigerating system acts is more uniform and stable, and the use requirement of the refrigerating environment is effectively met.

Description

Technical Field

[0001] The present application relates to the technical field of refrigeration equipment, and in particular to a low-temperature refrigeration system, a refrigeration method, a defrosting method, and a low-temperature storage box. Background Art

[0002] In the prior art, in low-temperature storage boxes, due to improper evaporator layout and airflow design, a significant temperature gradient exists vertically within the box. As the refrigerant flows through the evaporator tubes, the pressure drop and subcooling differences between the inlet and outlet sections lead to uneven heat exchange efficiency, resulting in lower temperatures near the evaporator inlet and higher temperatures near the outlet. Field measurements have shown that the vertical temperature difference within the box can exceed 5°C in some low-temperature storage boxes, seriously affecting the activity and safety of stored items and making it difficult to meet user requirements. Summary of the Invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a low-temperature refrigeration system, a refrigeration method, a defrosting method, and a low-temperature storage box. The low-temperature refrigeration system can reduce the spatial temperature gradient of the refrigeration environment, making the temperature within the refrigeration environment more uniform and stable, effectively meeting the use requirements of the refrigeration environment.

[0004] In a first aspect, the present application provides a low-temperature refrigeration system, comprising:

[0005] a first refrigeration circuit, comprising a compressor, a condenser, a gas-liquid separator, a main throttling device, and a condenser-evaporator connected in sequence, wherein a first outlet of the condenser-evaporator is connected to a refrigerant inlet of the compressor, the gas-liquid separator is used to separate the refrigerant flowing therethrough into liquid refrigerant and gaseous refrigerant, the liquid refrigerant outlet of the gas-liquid separator is connected to the refrigerant inlet of the main throttling device, and the gaseous refrigerant outlet of the gas-liquid separator is connected to the first inlet of the condenser-evaporator;

[0006] a second refrigeration circuit connected between the refrigerant outlet of the main throttle member and the second outlet of the condenser evaporator, the second refrigeration circuit comprising a first refrigeration branch and a second refrigeration branch connected in parallel, the first refrigeration branch comprising a first regulating valve, a first throttle member, and a first evaporator connected in sequence, the second refrigeration branch comprising a second regulating valve, a second throttle member, and a second evaporator connected in sequence, the first evaporator and the second evaporator being respectively located in a first area and a second area of ​​a refrigeration environment, the first area being connected to the second area;

[0007] The controller is configured to control and adjust the openings of the first regulating valve and the second regulating valve according to the temperature difference between the first area and the second area.

[0008] The low-temperature refrigeration system according to the first aspect of the present application has at least the following beneficial effects:

[0009] The low-temperature refrigeration system of the present application is composed of a high-temperature circulating refrigeration circuit through a first refrigeration circuit, and a low-temperature circulating refrigeration circuit is composed of a second refrigeration circuit, a condensing evaporator, a compressor, a condenser and a gas-liquid separator in the first refrigeration circuit. Refrigerants with different boiling points in the refrigerant are used to separate the refrigerant flowing out of the compressor into a liquid-enriched refrigerant and a gas-enriched refrigerant through a gas-liquid separator. The liquid-enriched refrigerant works in the high-temperature circulating refrigeration circuit, and the gas-enriched refrigerant works in the low-temperature circulating refrigeration circuit. The high-temperature circulating refrigeration circuit and the low-temperature circulating refrigeration circuit are coupled through the condensing evaporator. The high-temperature circulating refrigeration circuit is used to pre-cool the condensing evaporator serving as a condenser in the low-temperature circulating refrigeration circuit, thereby reducing the compression power consumption of the low-temperature circulating refrigeration circuit and forming a relatively constant low-temperature or ultra-low-temperature environment in the refrigeration environment with lower energy consumption.

[0010] At the same time, by respectively arranging the first evaporator and the second evaporator in the above-mentioned low-temperature stage circulating refrigeration circuit in the first area and the second area of ​​the refrigeration environment, the first area and the second area are connected, and the controller can control and adjust the opening of the first regulating valve and the second regulating valve according to the temperature difference between the first area and the second area to adjust the refrigerant flow of the first evaporator and the second evaporator, so that the heat exchange between the refrigerant in the first evaporator and the air in the first area and the heat exchange between the refrigerant in the second evaporator and the air in the second area are relatively uniform, thereby reducing the temperature difference between the first area and the second area to an acceptable range, narrowing the spatial temperature gradient of the refrigeration environment, and making the temperature in the refrigeration environment where the low-temperature refrigeration system acts more uniform and stable, effectively meeting the use requirements of the refrigeration environment.

[0011] In some embodiments, the first area and the second area are respectively provided with a first temperature sensor and a second temperature sensor, and both the first temperature sensor and the second temperature sensor are communicatively connected to the controller.

[0012] In some embodiments, a first blower is provided on one side of the first evaporator, and the first blower is used to accelerate the heat exchange between the air in the refrigeration environment and the refrigerant circulating in the first evaporator; a second blower is provided on one side of the second evaporator, and the second blower is used to accelerate the heat exchange between the air in the refrigeration environment and the refrigerant circulating in the second evaporator; the first blower and the second blower are both communicatively connected to the controller.

[0013] In some embodiments, the low-temperature refrigeration system also includes a first defrost branch, which is connected between the refrigerant outlet of the compressor and the refrigerant inlet of the first evaporator. A third regulating valve is provided on the first defrost branch, and the third regulating valve is communicated with the controller.

[0014] In some embodiments, the low-temperature refrigeration system also includes a second defrost branch, which is connected between the refrigerant outlet of the compressor and the refrigerant inlet of the second evaporator. A fourth regulating valve is provided on the second defrost branch, and the fourth regulating valve is communicated with the controller.

[0015] In some embodiments, the first evaporator and the second evaporator both have a refrigeration mode and a defrost mode. When one of the first evaporator and the second evaporator is in the defrost mode, the other is in the refrigeration mode.

[0016] In a second aspect, the present application provides a low-temperature storage box, comprising the low-temperature refrigeration system described above.

[0017] In a third aspect, the present application provides a refrigeration method, which is performed using the low-temperature refrigeration system described above, and comprises the following steps:

[0018] operating the low-temperature refrigeration system;

[0019] detecting a temperature difference between the first region and the second region;

[0020] When the temperature of the first area is greater than the temperature of the second area and the temperature difference between the two is greater than a preset temperature difference value, the opening of the second regulating valve is increased and the opening of the first regulating valve is decreased; when the temperature of the first area is lower than the temperature of the second area and the temperature difference between the two is greater than a preset temperature difference value, the opening of the second regulating valve is decreased and the opening of the first regulating valve is increased.

[0021] In some embodiments, the refrigeration method further comprises the following steps:

[0022] When the temperature of the first area is greater than the temperature of the second area and the temperature difference between the two areas is greater than a preset temperature difference value, increasing the air flow rate in the second area and reducing the air flow rate in the first area;

[0023] When the temperature of the first area is lower than the temperature of the second area and the temperature difference between the two areas is greater than a preset temperature difference value, the air flow rate in the second area is reduced, and the air flow rate in the first area is increased.

[0024] In a fourth aspect, the present application provides a defrosting method, which is performed using the above-mentioned low-temperature refrigeration system, and includes the following steps:

[0025] operating the low-temperature refrigeration system;

[0026] determining whether the first evaporator and the second evaporator meet defrosting conditions;

[0027] When the first evaporator meets the defrosting condition, the first regulating valve is closed, part of the refrigerant flowing out of the compressor is introduced into the first evaporator, and the opening of the second regulating valve is increased;

[0028] When the second evaporator meets the defrosting condition, the second regulating valve is closed, part of the refrigerant flowing out of the compressor is introduced into the second evaporator, and the opening of the first regulating valve is increased.

[0029] In some embodiments, the defrosting method further comprises the following steps:

[0030] When the first evaporator meets the defrosting condition, the first evaporator is air-dried; when the second evaporator meets the defrosting condition, the second evaporator is air-dried.

[0031] In some embodiments, the defrosting method further comprises the following steps:

[0032] After the first evaporator is defrosted, the first evaporator is continued to be air-dried until the evaporation rate of water on the first evaporator is greater than or equal to 95%;

[0033] After the second evaporator is defrosted, the second evaporator is continued to be air-dried until the evaporation rate of water on the second evaporator is greater than or equal to 95%.

[0034] In some embodiments, the defrosting method further comprises the following steps:

[0035] During the defrosting process of the first evaporator, detecting a first humidity at an outlet of a drain pipe of the first evaporator, and if the first humidity is greater than a first preset humidity value, continuing to air-dry the first evaporator until the first humidity is less than or equal to the first preset humidity value;

[0036] During the defrosting process of the second evaporator, the second humidity at the drain pipe outlet of the second evaporator is detected. If the second humidity is greater than a second preset humidity value, the second evaporator is continued to be air-dried until the second humidity is less than or equal to the second preset humidity value.

[0037] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0039] Figure 1 Schematic diagram of the low temperature refrigeration system of the embodiment of the present application Figure 1 .

[0040] Figure 2 Schematic diagram of the low temperature refrigeration system of the embodiment of the present application Figure 2 .

[0041] Figure 3 Schematic diagram of the low temperature refrigeration system of the embodiment of the present application Figure 3 .

[0042] Figure 4 Schematic diagram of the low temperature refrigeration system of the embodiment of the present application Figure 4 .

[0043] Explanation of the reference numerals: first refrigeration circuit R1; compressor 11; condenser 12; third blower 121; water collecting pan 122; gas-liquid separator 13; gas refrigerant outlet 131; liquid refrigerant outlet 132; main throttling device 14; condenser evaporator 15; first outlet 151; second outlet 152; first inlet 153; second inlet 154; filter 16; second refrigeration circuit R2; first refrigeration branch R21; first regulating valve 211; first throttling device 212; first evaporator 213; second refrigeration branch R22; second regulating valve 221; second throttling device 222; second evaporator 223; condensation pan 2231; first defrost branch R3; third regulating valve 31; second defrost branch R4; fourth regulating valve 41. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0046] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0047] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0048] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0049] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0050] A cryogenic storage box is a specialized device that maintains a constant low temperature through a mechanical refrigeration system. It is widely used in applications requiring long-term cryogenic storage of biological samples, pharmaceutical reagents, vaccines, and other products. The core principle of a cryogenic storage box is driven by a refrigeration cycle consisting of a compressor, condenser, evaporator, and throttling device. This system uses a refrigerant phase change to achieve directional heat transfer, creating a uniform and stable low-temperature environment within the box. Depending on the temperature range, cryogenic storage boxes are typically categorized into ultra-low temperature storage boxes, such as -40°C and -86°C.

[0051] In the prior art, in low-temperature storage boxes, due to improper evaporator layout and airflow design, a significant temperature gradient exists vertically within the box. As the refrigerant flows through the evaporator tubes, the pressure drop and subcooling differences between the inlet and outlet sections lead to uneven heat exchange efficiency, resulting in lower temperatures near the evaporator inlet and higher temperatures near the outlet. Field measurements have shown that the vertical temperature difference within the box can exceed 5°C in some low-temperature storage boxes, seriously affecting the activity and safety of stored items and making it difficult to meet user requirements.

[0052] Based on this, one or more embodiments of the present application provide a low-temperature refrigeration system, in which a high-temperature circulating refrigeration circuit is formed by a first refrigeration circuit, and a low-temperature circulating refrigeration circuit is formed by a second refrigeration circuit, a condensing evaporator in the first refrigeration circuit, a compressor, a condenser and a gas-liquid separator. Relying on the refrigerants with different boiling points in the refrigerant, the refrigerant flowing out of the compressor is separated into a liquid-enriched refrigerant and a gas-enriched refrigerant through a gas-liquid separator. The liquid-enriched refrigerant works in the high-temperature circulating refrigeration circuit, and the gas-enriched refrigerant works in the low-temperature circulating refrigeration circuit. The high-temperature circulating refrigeration circuit and the low-temperature circulating refrigeration circuit are coupled through the condensing evaporator, and the high-temperature circulating refrigeration circuit is used to pre-cool the condensing evaporator serving as a condenser in the low-temperature circulating refrigeration circuit, thereby reducing the compression power consumption of the low-temperature circulating refrigeration circuit and forming a relatively constant low-temperature or ultra-low-temperature environment with lower energy consumption.

[0053] At the same time, by respectively arranging the first evaporator and the second evaporator in the above-mentioned low-temperature circulating refrigeration circuit in the first area and the second area of ​​the refrigeration environment, the first area and the second area are connected, and the controller can control and adjust the opening of the first regulating valve and the second regulating valve according to the temperature difference between the first area and the second area to adjust the refrigerant flow of the first evaporator and the second evaporator, so that the heat exchange between the refrigerant in the first evaporator and the air in the first area and the heat exchange between the refrigerant in the second evaporator and the air in the second area are relatively uniform, thereby reducing the temperature difference between the first area and the second area to an acceptable range, narrowing the spatial temperature gradient of the refrigeration environment, and making the temperature in the refrigeration environment where the low-temperature refrigeration system acts more uniform and stable, effectively meeting the use requirements of the refrigeration environment.

[0054] See also Figure 1 , Figure 1 Schematic diagram of the low temperature refrigeration system of the embodiment of the present application Figure 1 ,exist Figure 1 In the figure, the dotted hollow arrows represent the direction of the refrigerant. Figures 2 to 4 Similarly, I will not elaborate on it.

[0055] An embodiment of the present application provides a low-temperature refrigeration system, which includes a first refrigeration circuit R1, a second refrigeration circuit R2, and a controller.

[0056] The first refrigeration circuit R1 includes a compressor 11, a condenser 12, a gas-liquid separator 13, a main throttling device 14 and a condensing evaporator 15 which are connected in sequence. The first outlet 151 of the condensing evaporator 15 is connected to the refrigerant inlet of the compressor 11. The gas-liquid separator 13 is used to separate the refrigerant flowing through it into liquid refrigerant and gaseous refrigerant. The liquid refrigerant outlet 132 of the gas-liquid separator 13 is connected to the refrigerant inlet of the main throttling device 14, and the gaseous refrigerant outlet 131 of the gas-liquid separator 13 is connected to the first inlet 153 of the condensing evaporator 15.

[0057] The second refrigeration circuit R2 is connected between the refrigerant outlet of the main throttle member 14 and the second outlet 152 of the condenser evaporator 15. The second refrigeration circuit R2 includes a first refrigeration branch R21 and a second refrigeration branch R22 connected in parallel. The first refrigeration branch R21 includes a first regulating valve 211, a first throttle member 212, and a first evaporator 213 connected in sequence. The second refrigeration branch R22 includes a second regulating valve 221, a second throttle member 222, and a second evaporator 223 connected in sequence. The first evaporator 213 and the second evaporator 223 are respectively located in a first area and a second area of ​​the refrigeration environment, and the first area and the second area are connected.

[0058] The controller (not shown in the figure) is used to control and adjust the opening of the first regulating valve 211 and the second regulating valve 221 according to the temperature difference between the first area and the second area.

[0059] It should be noted that the low-temperature refrigeration system of the present application is suitable for places where long-term low or ultra-low temperatures need to be maintained, such as low-temperature storage boxes for storing medical and biological samples, ultra-low temperature laboratories, food process storage boxes, etc.

[0060] In the present application, the compressor 11 is used to compress the refrigerant, which uses a non-azeotropic mixture, such as a non-azeotropic mixture of R600a (isobutane refrigerant) and R1150 (ethylene refrigerant). High-efficiency cascade refrigeration is achieved by utilizing the difference in boiling points of the refrigerants within the non-azeotropic refrigerant. The second inlet 154 of the condenser evaporator 15 is connected to the refrigerant outlet of the main throttle 14. The first inlet 153 and the second inlet 154 of the condenser evaporator 15 are the same inlet or different inlets spaced apart, and the first outlet 151 and the second outlet 152 of the condenser evaporator 15 are the same inlet or different inlets spaced apart.

[0061] In the first refrigeration circuit R1 of the present application, the compressor 11, the condenser 12, the gas-liquid separator 13, the main throttling device 14 and the condenser evaporator 15 are connected in sequence to form a complete refrigeration cycle circuit. The refrigeration principle of the first refrigeration circuit R1 is as follows: the high-temperature and high-pressure refrigerant flowing out of the compressor 11 enters the condenser 12 for pre-cooling and heat release, and becomes a medium-temperature and high-pressure refrigerant (liquid-gas phase mixture) after cooling. The medium-temperature and high-pressure refrigerant then enters the gas-liquid separator 13 for gas-liquid separation. Since the refrigerant is a non-azeotropic mixed working fluid, the gas-liquid separator 13 can separate the refrigerant into a medium-temperature and high-pressure refrigerant enriched in the liquid phase and a medium-temperature and high-pressure refrigerant enriched in the gas phase. The medium-temperature and high-pressure refrigerant enriched in the liquid phase flowing out of the liquid refrigerant outlet 132 of the gas-liquid separator 13 flows into the main throttling device 14, and becomes a low-temperature and low-pressure refrigerant enriched in the liquid phase after being depressurized by the main throttling device 14. During this process, the medium-temperature, high-pressure refrigerant enriched in the gas phase flowing out of the gas refrigerant outlet 131 of the gas-liquid separator 13 flows into the condenser evaporator 15. The low-temperature, low-pressure refrigerant enriched in the liquid phase flowing out of the main throttle 14 flows into the condenser evaporator 15 again to absorb the condensation heat of the medium-temperature, high-pressure refrigerant enriched in the gas phase in the condenser evaporator 15, and turns into a low-temperature, low-pressure gaseous refrigerant. Finally, the low-temperature, low-pressure gaseous refrigerant returns to the compressor 11 for the next step of compression and refrigeration.

[0062] It can be understood that the first refrigeration circuit R1 is also referred to as a high-temperature cycle refrigeration circuit. In the first refrigeration circuit R1 , the condenser evaporator 15 is used as an evaporator in the refrigeration cycle.

[0063] In the present application, the second refrigeration circuit R2, the condenser evaporator 15, the compressor 11, the condenser 12 and the gas-liquid separator 13 in the first refrigeration circuit R1 constitute a complete refrigeration cycle circuit, which is also called a low-temperature stage cycle refrigeration circuit. The refrigeration principle of the low-temperature cycle refrigeration circuit is as follows: the medium-temperature and high-pressure refrigerant enriched in the gas phase flowing out from the gaseous refrigerant outlet 131 of the gas-liquid separator 13 flows into the condensing evaporator 15, releases heat to the low-temperature and low-pressure refrigerant enriched in the liquid phase in the above-mentioned first refrigeration circuit R1, and becomes a medium-temperature and high-pressure refrigerant (liquid and gas phases are mixed, with more liquid phase), and the medium-temperature and high-pressure refrigerant then flows into the first refrigeration branch R21 and the second refrigeration branch R22 respectively; taking the first refrigeration branch R21 as an example, the medium-temperature and high-pressure refrigerant flows into the first regulating valve 211 and the first throttle member 212 in turn, and after throttling by the first throttle member 212, it becomes a low-temperature and low-pressure refrigerant, and the low-temperature and low-pressure refrigerant then enters the first evaporator 213 and absorbs the heat of the air in the first area where the first evaporator 213 is located, and becomes a low-temperature and low-pressure gaseous refrigerant, and finally the low-temperature and low-pressure gaseous refrigerant returns to the compressor 11 for the next step of compression and refrigeration; the second refrigeration branch R22 is the same and will not be repeated.

[0064] It is easy to understand that in the above-mentioned low-temperature stage cycle refrigeration circuit, the condenser evaporator 15 is used as a condenser in the refrigeration cycle.

[0065] In addition, see Figure 1 A third blower 121 and a water receiving tray 122 are set on one side of the condenser 12. The third blower 121 is used to blow air to cool the condenser 12, accelerate the heat release and pre-cooling of the refrigerant in the condenser 12, and the water receiving tray 122 is used to receive condensed water falling from the outer wall of the coil of the condenser 12.

[0066] In the above-mentioned low-temperature refrigeration system, the high-temperature circulating refrigeration circuit constituted by the first refrigeration circuit R1, the second refrigeration circuit R2, the condenser evaporator 15 in the first refrigeration circuit R1, the compressor 11, the condenser 12 and the gas-liquid separator 13 constitute the low-temperature circulating refrigeration circuit. Relying on the refrigerants with different boiling points in the refrigerant, the refrigerant flowing out of the compressor 11 is separated into a refrigerant enriched in liquid phase and a refrigerant enriched in gas phase through the gas-liquid separator 13. The refrigerant enriched in liquid phase works in the high-temperature circulating refrigeration circuit, and the refrigerant enriched in gas phase works in the low-temperature circulating refrigeration circuit. The high-temperature circulating refrigeration circuit and the low-temperature circulating refrigeration circuit are coupled through the condenser evaporator 15. The high-temperature circulating refrigeration circuit is used to pre-cool the condenser evaporator 15 serving as a condenser in the low-temperature circulating refrigeration circuit, thereby reducing the compression power consumption of the low-temperature circulating refrigeration circuit and forming a relatively constant low-temperature or ultra-low-temperature environment with lower energy consumption.

[0067] In addition, it should be noted that in the present application, by respectively arranging the first evaporator 213 and the second evaporator 223 in the above-mentioned low-temperature circulating refrigeration circuit in the first area and the second area of ​​the refrigeration environment, the first area and the second area are connected, and the controller can control and adjust the opening of the first regulating valve 211 and the second regulating valve 221 according to the temperature difference between the first area and the second area to adjust the refrigerant flow of the first evaporator 213 and the second evaporator 223, so that the refrigerant in the first evaporator 213 and the air in the first area exchange heat relatively evenly, and the refrigerant in the second evaporator 223 and the air in the second area exchange heat relatively evenly, thereby reducing the temperature difference between the first area and the second area to an acceptable range, reducing the spatial temperature gradient of the refrigeration environment, and making the temperature in the refrigeration environment where the low-temperature refrigeration system acts more uniform and stable, effectively meeting the use requirements of the refrigeration environment.

[0068] For example, the refrigerated environment described above can be the internal storage space of a low-temperature storage box, which is used to store items such as pharmaceuticals and biological samples. The low-temperature refrigeration system acts on this refrigerated environment to make the temperature within the refrigerated environment more uniform and stable, thereby improving the activity and safety of pharmaceuticals and biological samples. Of course, the refrigerated environment described above can also be an ultra-low temperature laboratory, a food processing storage box, etc.

[0069] In some embodiments of the present application, the first area and the second area are respectively provided with a first temperature sensor (not shown in the figure) and a second temperature sensor (not shown in the figure), and the first temperature sensor and the second temperature sensor are both communicatively connected to the controller.

[0070] It is easy to understand that when the low-temperature refrigeration system of the present application is in operation, the first temperature sensor detects the real-time temperature of the first area, which can be understood as the average temperature of the first area, and the second temperature sensor detects the real-time temperature of the second area, which can be understood as the average temperature of the second area. The controller obtains the real-time temperature of the first area detected by the first temperature sensor and the real-time temperature of the second area detected by the second temperature sensor, calculates the temperature difference between the real-time temperatures of the two areas, and when the temperature difference is greater than a preset temperature difference value, the controller controls and adjusts the opening of the first regulating valve 211 and the second regulating valve 221 to make the refrigerant flow distribution of the first evaporator 213 and the second evaporator 223 relatively uniform, so that the refrigerant in the first evaporator 213 exchanges heat with the air in the first area, and the refrigerant in the second evaporator 223 exchanges heat with the air in the second area relatively uniformly, thereby reducing the temperature difference between the first area and the second area to below the preset temperature difference value, reducing the overall spatial temperature gradient of the refrigeration environment, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0071] Furthermore, a first blower (not shown in the figure) is provided on one side of the first evaporator 213, and the first blower is used to accelerate the heat exchange between the air in the refrigeration environment and the refrigerant circulating in the first evaporator 213; a second blower (not shown in the figure) is provided on one side of the second evaporator 223, and the second blower is used to accelerate the heat exchange between the air in the refrigeration environment and the refrigerant circulating in the second evaporator 223; the first blower and the second blower are both communicatively connected to the controller.

[0072] Specifically, the first blower's blowing range covers the length of the first evaporator 213. The first blower's rotation disrupts the airflow within the first region, accelerating heat exchange between the air within the first region and the refrigerant circulating within the first evaporator 213. The first blower may be, but is not limited to, a crossflow blower, an axial flow blower, or the like. The specific structural type of the first blower is compatible with the structural type of the first evaporator 213 and is not limited thereto. For example, if the first evaporator 213 is a finned evaporator and the first blower is a crossflow blower, the higher the rotational speed of the first blower, the higher the heat exchange efficiency between the air within the first region and the refrigerant circulating within the first evaporator 213.

[0073] Similarly, the second blower's blowing range covers the length of the second evaporator 233. The second blower's rotation disrupts the airflow within the second area, accelerating heat exchange between the air within the second area and the refrigerant circulating within the second evaporator 233. The second blower can be, but is not limited to, a crossflow blower, an axial flow blower, or the like. The specific structural type of the second blower is compatible with the structural type of the second evaporator 233 and is not limited thereto. For example, if the second evaporator 233 is a finned evaporator and the second blower is a crossflow blower, the higher the speed of the second blower, the higher the heat exchange efficiency between the air within the second area and the refrigerant circulating within the second evaporator 233.

[0074] It should also be noted that, in the present application, the first evaporator 213 and the second evaporator 233 preferably have the same evaporator structure to reduce the corresponding structural design cost.

[0075] Based on the structure of the above-mentioned low-temperature refrigeration system, an embodiment of the present application further provides a refrigeration method, which is performed using the above-mentioned low-temperature refrigeration system. The refrigeration method includes the following steps:

[0076] Step S11, running the low-temperature refrigeration system;

[0077] Step S12: detecting the temperature difference between the first area and the second area;

[0078] Step S13: When the temperature of the first area is greater than the temperature of the second area and the temperature difference between the two is greater than the preset temperature difference value, increase the opening of the second regulating valve 221 and reduce the opening of the first regulating valve 211; when the temperature of the first area is lower than the temperature of the second area and the temperature difference between the two is greater than the preset temperature difference value, reduce the opening of the second regulating valve 221 and increase the opening of the first regulating valve 211.

[0079] Specifically, in the above step S12, the real-time temperature of the first area is detected by the first temperature sensor, and the real-time temperature of the second area is detected by the second temperature sensor. The controller calculates the temperature difference between the first area and the second area based on the detection signals of the first temperature sensor and the second sensor.

[0080] In the above step S13, when the temperature of the first area is greater than the temperature of the second area and the temperature difference between the two is greater than the preset temperature difference value, it means that the cooling effect of the first evaporator 213 on the first area is better than the cooling effect of the second evaporator 233 on the second area. At this time, the controller increases the opening of the second regulating valve 221 and reduces the opening of the first regulating valve 211 according to the temperature difference between the first area and the second area, so as to increase the refrigerant flow rate circulating in the second evaporator 233 and reduce the refrigerant flow rate circulating in the first evaporator 213, and accordingly increase the cooling capacity of the second evaporator 233 in the second area and reduce the cooling capacity of the first evaporator 213 in the first area, thereby reducing the temperature difference between the first area and the second area to below the preset temperature difference value, reducing the overall spatial temperature gradient of the refrigeration environment, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0081] Similarly, in the above step S13, when the temperature of the first area is lower than the temperature of the second area and the temperature difference between the two is greater than the preset temperature difference value, it means that the cooling effect of the first evaporator 213 on the first area is worse than the cooling effect of the second evaporator 233 on the second area. At this time, the controller reduces the opening of the second regulating valve 221 and increases the opening of the first regulating valve 211 according to the temperature difference between the first area and the second area, so as to reduce the refrigerant flow rate circulating in the second evaporator 233 and increase the refrigerant flow rate circulating in the first evaporator 213, and accordingly reduce the cooling capacity of the second evaporator 233 in the second area and increase the cooling capacity of the first evaporator 213 in the first area, thereby reducing the temperature difference between the first area and the second area to below the preset temperature difference value, reducing the overall spatial temperature gradient of the refrigeration environment, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0082] Furthermore, the refrigeration method further comprises the following steps:

[0083] Step S14: When the temperature of the first area is greater than the temperature of the second area and the temperature difference between the two is greater than a preset temperature difference value, increase the air flow rate in the second area and reduce the air flow rate in the first area; when the temperature of the first area is lower than the temperature of the second area and the temperature difference between the two is greater than a preset temperature difference value, reduce the air flow rate in the second area and increase the air flow rate in the first area.

[0084] It should be noted that, in the refrigeration method of the present application, there is no strict order between the above-mentioned step S13 and step S14, and the two can also be performed simultaneously.

[0085] Specifically, when the temperature of the first area is greater than that of the second area and the temperature difference between the two areas is greater than a preset temperature difference value, the refrigerant flow rate flowing through the second evaporator 233 is increased while the rotation speed of the second blower is increased to accelerate the heat exchange between the air in the second area and the refrigerant flowing through the second evaporator 233. The refrigerant flow rate flowing through the first evaporator 213 is reduced while the rotation speed of the first blower is reduced to slow down the heat exchange between the air in the first area and the refrigerant flowing through the first evaporator 213. In this way, the cooling capacity of the second evaporator 233 in the second area is rapidly increased while the cooling capacity of the first evaporator 213 in the first area is rapidly reduced, thereby reducing the temperature difference between the first area and the second area to below the preset temperature difference value, reducing the overall spatial temperature gradient of the refrigeration environment, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0086] Similarly, when the temperature of the first area is lower than that of the second area and the temperature difference between the two areas is greater than a preset temperature difference value, the refrigerant flow rate flowing through the second evaporator 233 is reduced while the rotation speed of the second blower is reduced to slow down the heat exchange between the air in the second area and the refrigerant flowing through the second evaporator 233. The refrigerant flow rate flowing through the first evaporator 213 is increased while the rotation speed of the first blower is increased to accelerate the heat exchange between the air in the first area and the refrigerant flowing through the first evaporator 213. In this way, the cooling capacity of the second evaporator 233 in the second area is rapidly reduced while the cooling capacity of the first evaporator 213 in the first area is rapidly increased, thereby reducing the temperature difference between the first area and the second area to below the preset temperature difference value, reducing the overall spatial temperature gradient of the refrigeration environment, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0087] In some embodiments of this application, see Figure 2 and Figure 4 The low-temperature refrigeration system also includes a first defrost branch R3, which is connected between the refrigerant outlet of the compressor 11 and the refrigerant inlet of the first evaporator 213. A third regulating valve 31 is provided on the first defrost branch R3, and the third regulating valve 31 is communicated with the controller.

[0088] See also Figure 3 and Figure 4 The low-temperature refrigeration system also includes a second defrost branch R4, which is connected between the refrigerant outlet of the compressor 11 and the refrigerant inlet of the second evaporator 223. A fourth regulating valve 41 is provided on the second defrost branch R4, and the fourth regulating valve 41 is communicated with the controller.

[0089] It should be noted that the low-temperature refrigeration system of the present application is used to create a low-temperature or ultra-low-temperature refrigeration environment. The first evaporator 213 and the second evaporator 223 will be at risk of frosting after long-term operation, which will correspondingly reduce the cooling effect of the first evaporator 213 and the second evaporator 223 on the environment.

[0090] Based on this, through the above-mentioned structural setting, when the amount of frost on the first evaporator 213 reaches a critical value, it indicates that the first evaporator 213 meets the defrost conditions and needs to enter the defrost mode to perform the defrost process. At this time, the controller can close the first regulating valve 211 and no longer supply the first evaporator 213 with a lower temperature refrigerant. At this time, the first evaporator 213 can be understood as being in a shut-down state, and the copper tube inside it can circulate refrigerant normally. At the same time, the controller opens the third regulating valve 31 and directs part of the high-temperature and high-pressure refrigerant flowing out of the compressor 11 into the first evaporator 213 through the first defrost branch R3, defrosting the first evaporator 213 with the high-temperature and high-pressure refrigerant. The condensed water formed by the frost blocks melting under heat can be collected into the condensate tray of the first evaporator 213 through the guide groove on the first evaporator 213, and then discharged through the drain pipe.

[0091] In the above process, the controller also increases the opening of the second regulating valve 221 accordingly, such as directly making the opening of the second regulating valve 221 100%, providing the maximum refrigerant flow supply to the second evaporator 223, increasing the cooling capacity of the second evaporator 223, compensating for the cooling capacity lost by the first evaporator 213 due to being in the defrost mode, reducing the probability of an increase in the temperature difference between the first area and the second area, and controlling the temperature difference between the first area and the second area to be below the preset temperature difference value. It can also reduce the overall spatial temperature gradient of the refrigeration environment, make the temperature of the refrigeration environment more uniform and stable, and effectively meet the use requirements of the refrigeration environment.

[0092] In the above process, a first ice thickness sensor (not shown in the figure) can be set on the first evaporator 213. The first ice thickness sensor is used to detect the frost thickness of the first evaporator 213 to determine whether the frost amount of the first evaporator 213 reaches a critical value, or to determine whether the first evaporator 213 needs to enter the defrost mode.

[0093] In addition, during the defrosting process of the first evaporator 213, the rotation speed of the first blower can be increased to dry the first evaporator 213, accelerate the air circulation in the area where the first evaporator 213 is located, and improve the defrosting efficiency of the first evaporator 213. Moreover, by increasing the rotation speed of the first blower during the defrosting process of the first evaporator 213, more airflow in the second area can be allowed to enter the first area, accelerating the mixing of airflows in the two areas, and similarly reducing the probability of an increase in the temperature difference between the first area and the second area, controlling the temperature difference between the first area and the second area to below a preset temperature difference value, and similarly reducing the overall spatial temperature gradient of the refrigeration environment. At the same time, the temperatures of the first area and the second area can be maintained at a relatively low level, making the temperature of the refrigeration environment more uniform and stable, effectively meeting the use requirements of the refrigeration environment.

[0094] Similarly, when the amount of frost on the second evaporator 223 reaches a critical value, it indicates that the second evaporator 223 meets the defrosting conditions and needs to enter the defrosting mode for defrosting. At this time, the controller can close the second regulating valve 221 and no longer supply the second evaporator 223 with a lower temperature refrigerant. At this time, the second evaporator 223 can be understood as being in a shutdown state, and the copper tube inside it can circulate refrigerant normally. At the same time, the controller opens the fourth regulating valve 41, and introduces part of the high-temperature and high-pressure refrigerant flowing out of the compressor 11 into the first evaporator 213 through the second defrost branch R4, and defrosts the second evaporator 223 with the high-temperature and high-pressure refrigerant. The condensed water formed by the melting of the frost blocks by heat can be collected into the condensate tray 2231 of the second evaporator 223 through the guide groove on the second evaporator 223, and then discharged through the drain pipe.

[0095] During the above process, the controller also increases the opening of the first regulating valve 211 accordingly, such as directly making the opening of the first regulating valve 211 100%, providing the maximum refrigerant flow supply to the first evaporator 213, increasing the cooling capacity of the first evaporator 213, compensating for the cooling capacity lost by the second evaporator 223 due to being in the defrost mode, reducing the probability of an increase in the temperature difference between the first area and the second area, and controlling the temperature difference between the first area and the second area to be below the preset temperature difference value. It can also reduce the overall spatial temperature gradient of the refrigeration environment, make the temperature of the refrigeration environment more uniform and stable, and effectively meet the use requirements of the refrigeration environment.

[0096] In the above process, a second ice thickness sensor (not shown in the figure) can be set on the second evaporator 223. The second ice thickness sensor is used to detect the frost thickness of the second evaporator 223 to determine whether the frost amount of the second evaporator 223 reaches a critical value, or to determine whether the second evaporator 223 needs to enter the defrost mode.

[0097] In addition, during the defrosting process of the second evaporator 223, the rotation speed of the second blower can be increased to dry the second evaporator 223, accelerate the air circulation in the area where the second evaporator 223 is located, and improve the defrosting efficiency of the second evaporator 223. Moreover, by increasing the rotation speed of the second blower during the defrosting process of the second evaporator 223, more airflow in the first area can be allowed to enter the second area, accelerating the mixing of airflows in the two areas. This can also reduce the probability of an increase in the temperature difference between the first area and the second area, and control the temperature difference between the first area and the second area to be below a preset temperature difference value. This can also reduce the overall spatial temperature gradient of the refrigeration environment, while maintaining the temperatures of both the first area and the second area at a lower state, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0098] In some embodiments of the present application, the first evaporator 213 and the second evaporator 223 both have a cooling mode and a defrosting mode. When one of the first evaporator 213 and the second evaporator 223 is in the defrosting mode, the other is in the cooling mode.

[0099] With this arrangement, the cooling capacity generated by the evaporator in refrigeration mode is used to compensate for the cooling capacity lost by the evaporator in defrost mode due to defrost shutdown, thereby reducing the probability of an increase in the temperature difference between the first area and the second area, and controlling the temperature difference between the first area and the second area to be below the preset temperature difference value. This can also reduce the overall spatial temperature gradient of the refrigeration environment, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0100] It should be additionally explained that when either the first evaporator 213 or the second evaporator 223 is in the defrost mode, all functional components on the first refrigeration circuit R1 are in operation, that is, the first refrigeration circuit R1 operates normally.

[0101] Based on the structure of the above-mentioned low-temperature refrigeration system, an embodiment of the present application further provides a defrosting method. The defrosting method is performed using the above-mentioned low-temperature refrigeration system. The defrosting method includes the following steps:

[0102] Step S21, running the low-temperature refrigeration system;

[0103] Step S22, determining whether the first evaporator 213 and the second evaporator 223 meet the defrosting conditions;

[0104] Step S23: When the first evaporator 213 meets the defrosting condition, the first regulating valve 211 is closed, part of the refrigerant flowing out of the compressor 11 is introduced into the first evaporator 213, and the opening of the second regulating valve 221 is increased;

[0105] Step S24 : When the second evaporator 223 meets the defrosting condition, the second regulating valve 221 is closed, part of the refrigerant flowing out of the compressor 11 is introduced into the second evaporator 223 , and the opening of the first regulating valve 211 is increased.

[0106] Specifically, in step S22, a first ice thickness sensor (not shown) may be provided on the first evaporator 213 to detect the thickness of frost on the first evaporator 213, thereby determining whether the amount of frost on the first evaporator 213 has reached a critical value. If the amount of frost on the first evaporator 213 has reached the critical value, the defrosting condition is satisfied. Similarly, a second ice thickness sensor (not shown) may be provided on the second evaporator 223 to detect the thickness of frost on the second evaporator 223, thereby determining whether the amount of frost on the second evaporator 223 has reached a critical value. If the amount of frost on the second evaporator 223 has reached the critical value, the defrosting condition is satisfied.

[0107] In step S23, when the first evaporator 213 meets the defrosting conditions, the first regulating valve 211 is closed, and the lower-temperature refrigerant is no longer supplied to the first evaporator 213. At this point, the first evaporator 213 can be considered to be in a shut-down state, and the copper pipes within it can normally circulate refrigerant. The third regulating valve 31 is opened, and a portion of the high-temperature, high-pressure refrigerant flowing out of the compressor 11 is directed into the first evaporator 213 through the first defrost branch R3. The high-temperature, high-pressure refrigerant defrosts the first evaporator 213. Condensed water formed by the melting of frost blocks by heat can flow through the guide grooves on the first evaporator 213 into the condensate pan of the first evaporator 213 and then be discharged through the drain pipe.

[0108] At the same time, the controller also increases the opening of the second regulating valve 221 accordingly, such as directly making the opening of the second regulating valve 221 100%, providing the maximum refrigerant flow supply to the second evaporator 223, increasing the cooling capacity of the second evaporator 223, compensating for the cooling capacity lost by the first evaporator 213 due to being in the defrost mode, reducing the probability of an increase in the temperature difference between the first area and the second area, and controlling the temperature difference between the first area and the second area to be below the preset temperature difference value. It can also reduce the overall spatial temperature gradient of the refrigeration environment, make the temperature of the refrigeration environment more uniform and stable, and effectively meet the use requirements of the refrigeration environment.

[0109] The same applies to step S24, which will not be described in detail.

[0110] It should be noted that the above steps S23 and S24 are performed simultaneously.

[0111] In combination with the above content, it is not difficult to understand that the defrosting method of the present application can effectively reduce the probability of an increase in the temperature difference between the first area and the second area, and control the temperature difference between the first area and the second area to below the preset temperature difference value. It can also reduce the overall spatial temperature gradient of the refrigeration environment. At the same time, it can also maintain the temperature of the first area and the second area at a lower state, making the temperature of the refrigeration environment more uniform and stable, effectively meeting the use requirements of the refrigeration environment.

[0112] In some embodiments of the present application, the defrosting method further includes the following steps:

[0113] Step S25: When the first evaporator 213 meets the defrosting condition, the first evaporator 213 is air-dried;

[0114] Step S26: When the second evaporator 223 meets the defrosting condition, the second evaporator 223 is air-dried.

[0115] Specifically, step S25 and step S26 are performed simultaneously.

[0116] In step S25, the rotation speed of the first blower can be increased to dry the first evaporator 213, accelerate the air circulation in the area where the first evaporator 213 is located, and improve the defrosting efficiency of the first evaporator 213. Moreover, by increasing the rotation speed of the first blower during the defrosting process of the first evaporator 213, more airflow in the second area can be allowed to enter the first area, accelerating the mixing of airflows in the two areas, and similarly reducing the probability of an increase in the temperature difference between the first area and the second area, controlling the temperature difference between the first area and the second area to be below a preset temperature difference value, and similarly reducing the overall spatial temperature gradient of the refrigeration environment. At the same time, the temperatures of the first area and the second area can be maintained at a relatively low level, making the temperature of the refrigeration environment more uniform and stable, and effectively meeting the use requirements of the refrigeration environment.

[0117] The same applies to step S26, which will not be described in detail.

[0118] The above-mentioned setting can quickly defrost the first evaporator 213 or the second evaporator 223, and at the same time, can reduce the probability of an increase in the temperature difference between the first area and the second area, and control the temperature difference between the first area and the second area to be below the preset temperature difference value. It can also reduce the overall spatial temperature gradient of the refrigeration environment, and at the same time, it can maintain the temperature of the first area and the second area at a lower state, making the temperature of the refrigeration environment more uniform and stable, effectively meeting the use requirements of the refrigeration environment.

[0119] In some embodiments of the present application, the defrosting method further includes the following steps:

[0120] Step S27 : After the defrosting of the first evaporator 213 is completed, the first evaporator 213 is continued to be air-dried until the evaporation rate of the water on the first evaporator 213 is greater than or equal to 95%.

[0121] Step S28 : After the defrosting of the second evaporator 223 is completed, the second evaporator 223 is continued to be air-dried until the evaporation rate of the water on the second evaporator 223 is greater than or equal to 95%.

[0122] Specifically, in step S27, the first ice thickness sensor can be used to detect whether the frost thickness of the first evaporator 213 is less than a preset frost layer thickness, thereby determining whether the first evaporator 213 has been defrosted. In addition, the first blower can be operated for 10-15 minutes after the first evaporator 213 has been defrosted, until the water evaporation rate on the first evaporator 213 is greater than or equal to 95%, to prevent the first evaporator 213 from frosting again.

[0123] Similarly, in step S28, the second ice thickness sensor can detect whether the frost thickness on the second evaporator 223 is less than a preset frost layer thickness, thereby determining whether defrosting of the second evaporator 223 is complete. Furthermore, the second blower can be operated for 10-15 minutes after defrosting of the second evaporator 223 is complete, until the water evaporation rate on the second evaporator 223 is greater than or equal to 95%, thereby preventing secondary frost on the second evaporator 223.

[0124] The above-mentioned defrosting method can effectively prevent the first evaporator 213 or the second evaporator 223 from frosting again in a short time after defrosting is completed.

[0125] In some embodiments of the present application, the defrosting method further includes the following steps:

[0126] Step S29: During the defrosting process of the first evaporator 213, a first humidity at the outlet of the drain pipe of the first evaporator 213 is detected. If the first humidity is greater than a first preset humidity value, the first evaporator 213 is continuously air-dried until the first humidity is less than or equal to the first preset humidity value.

[0127] In step S30, during the defrosting process of the second evaporator 223, the second humidity at the drain pipe outlet of the second evaporator 223 is detected. If the second humidity is greater than the second preset humidity value, the second evaporator 223 is continued to be air-dried until the second humidity is less than or equal to the second preset humidity value.

[0128] Specifically, in step S29, a first humidity sensor can be set at the drain pipe outlet of the first evaporator 213, and the first humidity at the drain pipe outlet of the first evaporator 213 can be detected by the first humidity sensor. Before the first humidity is less than or equal to the first preset humidity value, the first blower is continuously operated until the first humidity is less than or equal to the first preset humidity value, and then the first blower is shut down.

[0129] Similarly, in step S30, a second humidity sensor can be set at the drain pipe outlet of the second evaporator 223, and the second humidity at the drain pipe outlet of the second evaporator 223 can be detected by the second humidity sensor. Before the second humidity is less than or equal to the second preset humidity value, the second blower is continuously operated until the second humidity is less than or equal to the second preset humidity value, and then the second blower is shut down.

[0130] The first preset humidity value and the second preset humidity value can be selectively set according to the actual cooling demand of the cooling environment.

[0131] The above-mentioned defrosting method can effectively prevent the first evaporator 213 or the second evaporator 223 from frosting again in a short period of time after defrosting is completed due to high ambient humidity.

[0132] In addition, an embodiment of the present application further provides a low-temperature storage box, which includes the low-temperature refrigeration system of any of the above embodiments.

[0133] Low-temperature storage boxes include, but are not limited to, low-temperature storage boxes for storing medical and biological samples, ultra-low-temperature laboratories, and food processing storage boxes. The first evaporator 213 and the second evaporator 223 of the low-temperature refrigeration system can be respectively arranged in the longitudinal space within the low-temperature storage box, occupying at least 70% of the longitudinal space within the low-temperature storage box.

[0134] Obviously, the low-temperature storage box of the embodiment of the present application, since it is equipped with the above-mentioned low-temperature refrigeration system, also has the same technical effect brought by the low-temperature refrigeration system, that is, it can control the temperature difference of each area in the low-temperature storage box within an acceptable range, reduce the spatial temperature gradient in the low-temperature storage box, make the temperature in the low-temperature storage box more uniform and stable, and effectively meet the low-temperature storage needs.

[0135] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A low-temperature refrigeration system, characterized in that: include: a first refrigeration circuit, comprising a compressor, a condenser, a gas-liquid separator, a main throttling device, and a condenser-evaporator connected in sequence, wherein a first outlet of the condenser-evaporator is connected to a refrigerant inlet of the compressor, the gas-liquid separator is used to separate the refrigerant flowing therethrough into liquid refrigerant and gaseous refrigerant, the liquid refrigerant outlet of the gas-liquid separator is connected to the refrigerant inlet of the main throttling device, and the gaseous refrigerant outlet of the gas-liquid separator is connected to the first inlet of the condenser-evaporator; a second refrigeration circuit connected between the refrigerant outlet of the main throttle member and the second outlet of the condenser evaporator, the second refrigeration circuit comprising a first refrigeration branch and a second refrigeration branch connected in parallel, the first refrigeration branch comprising a first regulating valve, a first throttle member, and a first evaporator connected in sequence, the second refrigeration branch comprising a second regulating valve, a second throttle member, and a second evaporator connected in sequence, the first evaporator and the second evaporator being respectively located in a first area and a second area of ​​a refrigeration environment, the first area being connected to the second area; The controller is configured to control and adjust the openings of the first regulating valve and the second regulating valve according to the temperature difference between the first area and the second area.

2. The low-temperature refrigeration system according to claim 1, characterized in that: The first area and the second area are respectively provided with a first temperature sensor and a second temperature sensor, and the first temperature sensor and the second temperature sensor are both communicatively connected to the controller.

3. The low-temperature refrigeration system according to claim 2, characterized in that: A first blower is provided on one side of the first evaporator, and the first blower is used to accelerate heat exchange between the air in the refrigeration environment and the refrigerant circulating in the first evaporator; A second blower is provided on one side of the second evaporator, and the second blower is used to accelerate heat exchange between the air in the refrigeration environment and the refrigerant circulating in the second evaporator; The first blower and the second blower are both in communication connection with the controller.

4. The low-temperature refrigeration system according to claim 1, characterized in that The low-temperature refrigeration system also includes a first defrost branch, which is connected between the refrigerant outlet of the compressor and the refrigerant inlet of the first evaporator. A third regulating valve is provided on the first defrost branch, and the third regulating valve is communicatively connected to the controller.

5. The low-temperature refrigeration system according to claim 4, characterized in that: The low-temperature refrigeration system also includes a second defrost branch, which is connected between the refrigerant outlet of the compressor and the refrigerant inlet of the second evaporator. A fourth regulating valve is provided on the second defrost branch, and the fourth regulating valve is communicatively connected to the controller.

6. The low-temperature refrigeration system according to any one of claims 1 to 5, characterized in that: The first evaporator and the second evaporator both have a cooling mode and a defrosting mode. When one of the first evaporator and the second evaporator is in the defrosting mode, the other is in the cooling mode.

7. A low temperature storage box, characterized in that: Comprising the low-temperature refrigeration system according to any one of claims 1 to 6.

8. A refrigeration method, characterized in that: The refrigeration method is performed using the low-temperature refrigeration system according to any one of claims 1 to 6, and comprises the following steps: operating the low-temperature refrigeration system; detecting a temperature difference between the first region and the second region; When the temperature of the first area is greater than the temperature of the second area and the temperature difference between the two is greater than a preset temperature difference value, the opening of the second regulating valve is increased and the opening of the first regulating valve is decreased; when the temperature of the first area is lower than the temperature of the second area and the temperature difference between the two is greater than a preset temperature difference value, the opening of the second regulating valve is decreased and the opening of the first regulating valve is increased.

9. The refrigeration method according to claim 8, characterized in that: The following steps are also included: When the temperature of the first area is greater than the temperature of the second area and the temperature difference between the two areas is greater than a preset temperature difference value, increasing the air flow rate in the second area and reducing the air flow rate in the first area; When the temperature of the first area is lower than the temperature of the second area and the temperature difference between the two areas is greater than a preset temperature difference value, the air flow rate in the second area is reduced, and the air flow rate in the first area is increased.

10. A defrosting method, characterized in that: The defrosting method is performed using the low-temperature refrigeration system according to any one of claims 1 to 6, and comprises the following steps: operating the low-temperature refrigeration system; determining whether the first evaporator and the second evaporator meet defrosting conditions; When the first evaporator meets the defrosting condition, the first regulating valve is closed, part of the refrigerant flowing out of the compressor is introduced into the first evaporator, and the opening of the second regulating valve is increased; When the second evaporator meets the defrosting condition, the second regulating valve is closed, part of the refrigerant flowing out of the compressor is introduced into the second evaporator, and the opening of the first regulating valve is increased.

11. The defrosting method according to claim 10, characterized in that: The following steps are also included: When the first evaporator meets the defrosting condition, the first evaporator is air-dried; when the second evaporator meets the defrosting condition, the second evaporator is air-dried.

12. The defrosting method according to claim 10, characterized in that: The following steps are also included: After the first evaporator is defrosted, the first evaporator is continued to be air-dried until the evaporation rate of water on the first evaporator is greater than or equal to 95%; After the second evaporator is defrosted, the second evaporator is continued to be air-dried until the evaporation rate of water on the second evaporator is greater than or equal to 95%.

13. The defrosting method according to claim 10, characterized in that: The following steps are also included: During the defrosting process of the first evaporator, detecting a first humidity at an outlet of a drain pipe of the first evaporator, and if the first humidity is greater than a first preset humidity value, continuing to air-dry the first evaporator until the first humidity is less than or equal to the first preset humidity value; During the defrosting process of the second evaporator, the second humidity at the drain pipe outlet of the second evaporator is detected. If the second humidity is greater than a second preset humidity value, the second evaporator is continued to be air-dried until the second humidity is less than or equal to the second preset humidity value.

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