A self-cascade refrigeration system and its control method, and a constant temperature and humidity environment chamber.

Abstract

This invention discloses a self-cascade refrigeration system, its control method, and a constant temperature and humidity environment chamber. The self-cascade refrigeration system includes: a compressor, a first heat exchanger, a gas-liquid separator, a second heat exchanger, a first throttling component, a second throttling component, a third throttling component, an evaporator, a first valve, a second valve, an expansion branch, and a control module. The control module is configured to control the system's operating mode by controlling the opening and closing of the first throttling component, the second throttling component, the third throttling component, the first valve, and the second valve. The operating modes include a temperature mode and a humidity mode. During the temperature mode and the switching between temperature and humidity modes, the compressor's discharge temperature and discharge pressure are adjusted by regulating the expansion branch. In the humidity mode, the compressor's discharge temperature and discharge pressure are adjusted by controlling the second throttling component. This system can prevent the compressor from experiencing excessively high discharge pressure and temperature, improving the compressor's reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental test equipment, and in particular to a self cascade refrigeration system, a control method thereof and a constant temperature and humidity environmental chamber. BACKGROUND

[0002] At present, the refrigeration system of the constant temperature and humidity test chamber is mostly a dual cascade refrigeration system. The refrigeration system needs two compressors, the system structure is relatively complex, and the energy consumption is relatively high. In addition, when doing humidity, only one compressor is needed in most cases, which leads to the other compressor being idle, resulting in resource waste and occupying a large test chamber space.

[0003] The self cascade refrigeration system can not only produce a temperature below-70℃, but also has only one compressor, the system structure is simpler, and the cost is lower. Therefore, the system has been used in the fields of low-temperature refrigerators, vacuum coating and liquefied natural gas. Because the system has a high exhaust pressure and a high exhaust temperature in the high temperature zone, which has a great impact on the reliability of the compressor, it has been rarely used in the environmental test chamber. SUMMARY

[0004] The present application provides a self cascade refrigeration system, a control method thereof and a constant temperature and humidity environmental chamber, so as to realize the refrigeration and humidity application of the environmental test chamber, and avoid the high exhaust temperature and pressure of the compressor, and improve the reliability of the compressor.

[0005] According to an aspect of the present application, a self cascade refrigeration system is provided, which comprises a compressor, a first heat exchanger, a gas-liquid separator, a second heat exchanger, a first throttling component, a second throttling component, a third throttling component, an evaporator, a first valve, a second valve, an expansion branch and a control module.

[0006] The compressor is connected with the first heat exchanger, the first heat exchanger is connected with the input end of the gas-liquid separator, the first output end of the gas-liquid separator is connected with the first input end of the second heat exchanger, and the second output end of the gas-liquid separator is connected with the second throttling component and the third throttling component respectively.

[0007] The first output end of the second heat exchanger is connected with the first throttling component, the first input end of the second heat exchanger is connected with the second throttling component, and the second output end of the second heat exchanger is connected with the first valve, the second valve and the compressor respectively.

[0008] The input end of the evaporator is connected with the first throttling component and the third throttling component respectively, and the output end of the evaporator is connected with the first valve and the second valve respectively; the expansion branch is connected with the first output end of the gas-liquid separator and the compressor respectively;

[0009] The control module is electrically connected with at least the first throttling component, the second throttling component, the third throttling component, the first valve, the second valve and the expansion branch;

[0010] The control module is configured to control the working mode of the system by controlling the opening or closing of the first throttling component, the second throttling component, the third throttling component, the first valve and the second valve; wherein the working mode includes a temperature mode and a humidity mode;

[0011] And in the temperature mode and the temperature mode and the humidity mode switching process, the exhaust temperature and the exhaust pressure of the compressor are adjusted by adjusting the expansion branch; in the humidity mode, the exhaust temperature and the exhaust pressure of the compressor are adjusted by controlling the second throttling component.

[0012] Optionally, the control module is further configured to control the system to run in the temperature mode by controlling the first throttling component, the second throttling component and the first valve to be opened, and the third throttling component and the second valve to be closed.

[0013] Optionally, the expansion branch includes a first electromagnetic valve, a first pressure detection unit, a second electromagnetic valve, a second pressure detection unit and an expansion container; wherein the first electromagnetic valve is connected with the first output end of the gas-liquid separator and the expansion container respectively, and the second electromagnetic valve is connected with the expansion container and the compressor respectively; the first pressure detection unit is arranged between the first electromagnetic valve and the gas-liquid separator, and the second pressure detection unit is arranged between the second electromagnetic valve and the compressor;

[0014] The first pressure detection unit is used to detect the pressure on the high-pressure side of the system, and the second pressure detection unit is used to detect the pressure on the low-pressure side of the system;

[0015] The first electromagnetic valve is used to be opened when the pressure on the high-pressure side is greater than a first preset pressure; the second electromagnetic valve is used to be opened when the pressure on the low-pressure side is less than a second preset pressure; and the expansion container is used to store refrigerant.

[0016] Optionally, the control module is further configured to: in the temperature mode, when the pressure on the high-pressure side is greater than the first preset pressure, control the first solenoid valve to open so as to store the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator into the expansion container; and when the pressure on the low-pressure side is less than the second preset pressure, control the second solenoid valve to open so as to release the gaseous low-boiling-point refrigerant stored in the expansion container into the system, so as to adjust the exhaust temperature and exhaust pressure of the compressor.

[0017] Optionally, the control module is further configured to: during the process of switching from the temperature mode to the humidity mode, when the pressure on the high-pressure side is greater than the first preset pressure, control the first solenoid valve to open so as to store the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator into the expansion container, until the pressure on the high-pressure side is less than the first preset pressure, and then control the first solenoid valve to close.

[0018] Optionally, the control module is further configured to: during the process of switching from the humidity mode to the temperature mode, when the pressure on the low-pressure side is less than the second preset pressure, control the second solenoid valve to open so as to release the gaseous low-boiling-point refrigerant stored in the expansion container into the system.

[0019] Optionally, the control module is further configured to control the system to operate in the humidity mode by controlling the third throttling component and the second valve to open, and the first throttling component and the first valve to close.

[0020] Optionally, the control module is further configured to: in the humidity mode, when the temperature and humidity of the system meet preset conditions, control the second throttling component to open, so that the liquid high-boiling-point refrigerant output from the first output end of the gas-liquid separator mixes with the high-temperature gaseous high-boiling-point refrigerant output from the evaporator, so as to adjust the exhaust temperature and exhaust pressure of the compressor.

[0021] According to another aspect of the present invention, a control method for a self-cascaded cooling system as described in the first aspect is provided, the method comprising:

[0022] The operating mode of the system is controlled by opening or closing the first throttling component, the second throttling component, the third throttling component, the first valve, and the second valve; wherein the operating mode includes a temperature mode and a humidity mode;

[0023] During the temperature mode and the switching between the temperature mode and the humidity mode, the exhaust temperature and exhaust of the compressor are adjusted by adjusting the expansion branch; in the humidity mode, the exhaust temperature and exhaust pressure of the compressor are adjusted by controlling the second throttling component.

[0024] According to another aspect of the present invention, a constant temperature and humidity environment chamber is provided, which includes a self-cascading refrigeration system as described in the first aspect.

[0025] The technical solution of this invention provides a self-cascade refrigeration system and its control method, as well as a constant temperature and humidity environment chamber. The self-cascade refrigeration system includes: a compressor, a first heat exchanger, a gas-liquid separator, a second heat exchanger, a first throttling component, a second throttling component, a third throttling component, an evaporator, a first valve, a second valve, an expansion branch, and a control module. The compressor is connected to the first heat exchanger, and the first heat exchanger is connected to the input end of the gas-liquid separator. The first output end of the gas-liquid separator is connected to the first input end of the second heat exchanger, and the second output end of the gas-liquid separator is connected to the second throttling component and the third throttling component, respectively. The first output end of the second heat exchanger is connected to the first throttling component, the first input end of the second heat exchanger is connected to the second throttling component, and the second output end of the second heat exchanger is connected to the first valve, the second valve, and the compressor, respectively. The input terminals of the evaporator are connected to the first and third throttling components, respectively, and the output terminals of the evaporator are connected to the first and second valves, respectively. The expansion branch is connected to the first output terminal of the gas-liquid separator and the compressor, respectively. The control module is electrically connected to at least the first, second, and third throttling components, the first and second valves, and the expansion branch. The control module is configured to control the system's operating mode by controlling the opening and closing of the first, second, and third throttling components, the first valve, and the second valve. The operating modes include a temperature mode and a humidity mode. During the temperature mode and the switching between temperature and humidity modes, the compressor's discharge temperature and pressure are adjusted by regulating the expansion branch. In the humidity mode, the compressor's discharge temperature and pressure are adjusted by controlling the second throttling component. Therefore, by setting the first, second, and third throttling components, the first and second valves, and the expansion branch, the temperature and humidity modes of the refrigeration system can be controlled, enabling the self-cascade refrigeration system to be applied in the refrigeration system and dehumidification of environmental test chambers. Furthermore, during the switching between temperature mode and temperature and humidity modes, the compressor's discharge temperature and pressure are adjusted by regulating the expansion branch. In humidity mode, the compressor's discharge temperature and pressure are adjusted by controlling the second throttling component. This avoids excessively high discharge pressure and temperature, preventing damage to the compressor, improving compressor reliability, and ensuring the safe, efficient, and reliable operation of the system. As a result, the self-cascade refrigeration system can not only avoid high discharge pressure and temperature in the high-temperature zone of the environmental chamber, but also control humidity, thereby reducing the complexity of the refrigeration system and requiring less space.

[0026] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a self-cascade refrigeration system provided in an embodiment of the present invention;

[0029] Figure 2 This is a circuit structure block diagram of a self-cascading system provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of another self-cascade refrigeration system provided in an embodiment of the present invention;

[0031] Figure 4 This is a circuit structure block diagram of a self-cascading system provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of refrigerant flow under temperature mode provided in the embodiments of the present invention;

[0033] Figure 6 This is a schematic diagram of refrigerant flow under humidity mode provided in the embodiments of the present invention;

[0034] Figure 7 This is a flowchart of a control method for a self-cascaded refrigeration system provided in an embodiment of the present invention. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] Figure 1 This is a schematic diagram of a self-cascade refrigeration system provided in an embodiment of the present invention. Figure 2 This is a circuit structure block diagram of a self-cascading system provided in an embodiment of the present invention. (Reference) Figure 1 and Figure 2 The self-cascade refrigeration system includes: a compressor 1, a first heat exchanger 3, a gas-liquid separator 4, a second heat exchanger 5, a first throttling assembly 6, a second throttling assembly 7, a third throttling assembly 8, an evaporator 9, a first valve 10, a second valve 11, an expansion branch 20, and a control module 30. The compressor 1 is connected to the first heat exchanger 3, and the first heat exchanger 3 is connected to the input end of the gas-liquid separator 4. The first output end of the gas-liquid separator 4 is connected to the first input end of the second heat exchanger 5, and the second output end of the gas-liquid separator 4 is connected to the second throttling assembly 7 and the third throttling assembly 8, respectively. The first output end of the second heat exchanger 5 is connected to the first throttling assembly 6, the first input end of the second heat exchanger 5 is connected to the second throttling assembly 7, and the second output end of the second heat exchanger 5 is connected to the first valve 10, the second valve 11, and the compressor 1, respectively. The input end of the evaporator 9 is connected to the first throttling assembly 6 and the third throttling assembly 8, respectively. The throttling assembly 8 is connected, and the output end of the evaporator 9 is connected to the first valve 10 and the second valve 11 respectively; the expansion branch 20 is connected to the first output end of the gas-liquid separator 4 and the compressor 1 respectively; wherein, the control module 30 is electrically connected to at least the first throttling assembly 6, the second throttling assembly 7, the third throttling assembly 8, the first valve 10, the second valve 11 and the expansion branch 20; the control module 30 is configured to control the system's operating mode by controlling the opening or closing of the first throttling assembly 6, the second throttling assembly 7, the third throttling assembly 8, the first valve 10 and the second valve 11; wherein, the operating mode includes a temperature mode and a humidity mode; and during the temperature mode and the switching between the temperature mode and the humidity mode, the exhaust temperature and exhaust pressure of the compressor 1 are adjusted by adjusting the expansion branch 20; in the humidity mode, the exhaust temperature and exhaust pressure of the compressor 1 are adjusted by controlling the second throttling assembly 7.

[0038] refer to Figure 1 The self-cascade refrigeration system also includes an oil separator 2. The input end of the oil separator 2 is connected to the compressor 1, and the first output end of the oil separator 2 is connected to the first heat exchanger 3. The oil separator 2 is connected to the compressor 1 through an oil return line, so that the refrigeration oil separated by it can return to the compressor 1 through the oil return line.

[0039] The refrigerant used in this self-cascade refrigeration system is a mixed refrigerant. This mixed refrigerant is composed of one or more high-boiling-point refrigerants and one or more low-boiling-point refrigerants. The high-boiling-point refrigerant condenses more easily into a liquid state in the first heat exchanger 3, while the low-boiling-point refrigerant is difficult to condense into a liquid state in the first heat exchanger 3. Therefore, the refrigerant flowing in the first heat exchanger 3 is a gas-liquid two-phase mixed refrigerant.

[0040] The control module 30 is electrically connected to the first throttling component 6, the second throttling component 7, the third throttling component 8, the first valve 10, the second valve 11, and the expansion branch 20. The control module 30 can control the opening or closing of the first throttling component 6, the second throttling component 7, the third throttling component 8, the first valve 10, and the second valve 11. The control module 30 can be a PLC or other controller; its specific configuration can be determined based on actual conditions and is not limited here.

[0041] The compressor 1 is used to compress the mixed refrigerant into a high-temperature, high-pressure gaseous mixed refrigerant, which is then output to the oil separator 2.

[0042] The oil separator 2 is used to separate the refrigeration oil carried in the high-temperature and high-pressure gaseous mixed refrigerant output by the compressor 1, and then return it to the compressor 1 through the oil return pipeline of the oil separator 2, so as to ensure that the compressor can work for a long time without lack of lubricating oil.

[0043] The first heat exchanger 3 is used to exchange heat with the high-temperature, high-pressure gaseous refrigerant mixture output from the oil separator 2. The high-boiling-point refrigerant condenses into a liquid state after passing through the first heat exchanger 3. Since the low-boiling-point refrigerant is difficult to condense in the first heat exchanger 3, it remains a gaseous refrigerant. Therefore, the refrigerant in the first heat exchanger 3 is a gas-liquid two-phase mixture.

[0044] The gas-liquid separator 4 separates the gas-liquid two-phase refrigerant mixture output from the first heat exchanger 3, separating the liquid high-boiling-point refrigerant from the gaseous low-boiling-point refrigerant. The liquid high-boiling-point refrigerant is separated at the bottom of the gas-liquid separator 4 and flows out from the bottom pipe (i.e., the second output end of the gas-liquid separator 4). When the second throttling component 7 is open, it can enter the second heat exchanger 5 through the second throttling component 7, where it evaporates and absorbs heat on its low-temperature side, becoming a gaseous high-boiling-point refrigerant. The gaseous low-boiling-point refrigerant is separated by the gas-liquid separator 4 and flows out from the top of the gas-liquid separator 4 (i.e., the first output end of the gas-liquid separator 4) into the second heat exchanger 5. It undergoes heat exchange on the high-temperature side of the second heat exchanger 5, releasing heat and condensing into a liquid low-boiling-point refrigerant. When the first throttling component 6 is open, the liquid low-boiling-point refrigerant can enter the evaporator 9 through the first throttling component 6.

[0045] In temperature mode, the evaporator 9 is used to exchange heat with the liquid low-boiling-point refrigerant entering the evaporator 9 to generate cooling capacity, thereby converting it into gaseous low-boiling-point refrigerant. In humidity mode, the liquid high-boiling-point refrigerant is dehumidified to obtain gaseous high-boiling-point refrigerant.

[0046] The first valve 10 is installed on the connecting pipe between the output end of the evaporator 9 and the compressor 1, and is used to control the opening and closing of the connecting pipe. The second valve 11 is installed on the connecting pipe between the output end of the evaporator 9 and the compressor 1, and is used to control the opening and closing of the connecting pipe and to regulate the pressure inside the evaporator 9.

[0047] The temperature and humidity mode switching process includes switching from temperature mode to humidity mode and switching from humidity mode to temperature mode.

[0048] In the technical solution of this embodiment, the implementation process of the self-cascade cooling system is as follows: (Refer to...) Figure 1 and Figure 2The self-cascade refrigeration system includes: a compressor 1, a first heat exchanger 3, a gas-liquid separator 4, a second heat exchanger 5, a first throttling component 6, a second throttling component 7, a third throttling component 8, an evaporator 9, a first valve 10, a second valve 11, an expansion branch 20, and a control module 30. The control module 30 controls the opening and closing of the first throttling component 6, the second throttling component 7, the third throttling component 8, the first valve 10, and the second valve 11, selecting the system's operating mode. In temperature mode, when repeated high-temperature cooling and low-temperature heating are required, the pressure and temperature of the system are adjusted by regulating the expansion branch 20, thereby regulating the discharge pressure and temperature of the compressor 1. This prevents the compressor 1 from experiencing high discharge pressure and high discharge temperature in the high-temperature zone, improving the reliability of the compressor 1, preventing compressor damage, ensuring the safe and efficient operation of the refrigeration system, and enabling the system to be better applied in refrigeration. In switching between temperature and humidity modes, when the system pressure is too high or too low, the system pressure and temperature can be adjusted by regulating the expansion branch 20, thereby regulating the discharge pressure and temperature of compressor 1. This prevents compressor 1 from experiencing high discharge pressure and temperature in the high-temperature zone, thus improving the reliability of compressor 1, preventing compressor damage, and ensuring the safe and efficient operation of the refrigeration system. In humidity mode, when the relative humidity is high and the humidity is also high (i.e., high temperature and high humidity), the system pressure and temperature can be adjusted by regulating the second throttling component 7, thereby regulating the discharge pressure and temperature of compressor 1. This prevents compressor 1 from experiencing high discharge pressure and temperature in the high-temperature zone, thus improving the reliability of compressor 1, preventing compressor damage, ensuring the safe and efficient operation of the refrigeration system, and allowing the system to be better applied to humidity regulation. Therefore, by setting the first throttling component 6, the second throttling component 7, the third throttling component 8, the first valve 10, the second valve 11, and the expansion branch 20, the selection and control of the system's operating mode can be achieved, allowing the self-cascade refrigeration system to be applied to both refrigeration and dehumidification. Furthermore, during the switching between temperature mode and temperature / humidity mode, the discharge temperature and pressure of compressor 1 are adjusted by regulating the expansion branch 20. In humidity mode, the discharge temperature and pressure of compressor 1 are adjusted by controlling the second throttling component 7. This prevents excessively high discharge pressure and temperature in compressor 1, avoiding damage and improving its reliability. It ensures the safe, efficient, and reliable operation of the system, allowing this self-cascade refrigeration system to be used not only in high-temperature areas without excessive discharge pressure and temperature, but also in humidity applications, solving the problems of existing bipolar cascade refrigeration systems. In addition, it simplifies the structure of the refrigeration system, saves equipment space, reduces energy consumption and costs, and avoids resource waste.

[0049] The technical solution of this embodiment provides a self-cascade refrigeration system, which includes: a compressor, a first heat exchanger, a gas-liquid separator, a second heat exchanger, a first throttling component, a second throttling component, a third throttling component, an evaporator, a first valve, a second valve, an expansion branch, and a control module; wherein, the compressor is connected to the first heat exchanger, and the first heat exchanger is connected to the input end of the gas-liquid separator; the first output end of the gas-liquid separator is connected to the first input end of the second heat exchanger, and the second output end of the gas-liquid separator is connected to the second throttling component and the third throttling component respectively; the first output end of the second heat exchanger is connected to the first throttling component, the first input end of the second heat exchanger is connected to the second throttling component, and the second output end of the second heat exchanger is connected to the first valve, the second valve, and the compressor respectively; the input end of the evaporator is connected to the first valve, the second valve, and the compressor respectively; the first output end of the second heat exchanger is connected to the first valve, the second valve, and the compressor respectively; the first output ... The evaporator's output is connected to the first and third throttling components, respectively, and the expansion branch is connected to the first output of the gas-liquid separator and the compressor. The control module is electrically connected to at least the first, second, and third throttling components, the first and second valves, and the expansion branch. The control module is configured to control the system's operating mode by controlling the opening and closing of the first, second, and third throttling components, the first valve, and the second valve. The operating modes include a temperature mode and a humidity mode. During the temperature mode and the switching between temperature and humidity modes, the compressor's discharge temperature and pressure are adjusted by regulating the expansion branch. In the humidity mode, the compressor's discharge temperature and pressure are adjusted by controlling the second throttling component. Therefore, by setting the first, second, and third throttling components, the first and second valves, and the expansion branch, the temperature and humidity modes of the refrigeration system can be controlled, enabling the self-cascade refrigeration system to be applied in the refrigeration system and dehumidification of environmental test chambers. Furthermore, during the switching between temperature mode and temperature and humidity modes, the compressor's discharge temperature and pressure are adjusted by regulating the expansion branch. In humidity mode, the compressor's discharge temperature and pressure are adjusted by controlling the second throttling component. This avoids excessively high discharge pressure and temperature, preventing damage to the compressor, improving compressor reliability, and ensuring the safe, efficient, and reliable operation of the system. As a result, the self-cascade refrigeration system can not only avoid high discharge pressure and temperature in the high-temperature zone of the environmental chamber, but also control humidity, thereby reducing the complexity of the refrigeration system and requiring less space.

[0050] Based on the above embodiments, optionally, the structures of the first throttling component 6, the second throttling component 7, and the third throttling component 8 may be the same or different. The throttling component may include: a capillary tube and a quick-opening solenoid valve connected in series; or a solenoid valve and an electronic expansion valve connected in series; or a thermostatic expansion valve and a solenoid valve connected in series.

[0051] It should be noted that the specific structural composition of the first throttling component 6, the second throttling component 7, and the third throttling component 8 can be set according to the actual situation, and no specific limitation is made here.

[0052] Optionally, the first valve 10 is a bypass solenoid valve, and the second valve 11 is an evaporation pressure regulating valve.

[0053] Optionally, the first heat exchanger 3 is a condenser, and the second heat exchanger 5 is an evaporator-condenser.

[0054] Optionally, the control module is also configured to control the system to operate in temperature mode by controlling the first throttling component 6, the second throttling component 7 and the first valve 10 to open, and the third throttling component 8 and the second valve 11 to close.

[0055] When temperature mode is required, the control module 30 controls the opening of the first throttling component 6, the second throttling component 7, and the first valve 10, while closing the third throttling component 8 and the second valve 11, to control the system to operate in temperature mode. In temperature mode, because the first throttling component 6 is open, the refrigerant that exchanges heat and releases heat on the high-temperature side of the second heat exchanger 5, condensing into a liquid low-boiling-point refrigerant, can enter the evaporator 9 through the first throttling component 6 to exchange heat and generate cooling capacity, becoming a gaseous low-boiling-point refrigerant. Because the second throttling component 7 is open and the third throttling component 8 is closed, the liquid high-boiling-point refrigerant flows out from the bottom of the gas-liquid separator 4, enters the second heat exchanger 5 through the second throttling component 7, evaporates and absorbs heat on the low-temperature side of the second heat exchanger 5, becoming a gaseous high-boiling-point refrigerant, which flows out from the second output end of the second heat exchanger 5. In temperature mode, the first valve 10 is open, and the gaseous low-boiling-point refrigerant from the evaporator 9 flows through the first valve 10 and mixes with the gaseous high-boiling-point refrigerant from the second output end of the second heat exchanger 5 before returning to the suction port of the compressor 1, thus completing the refrigeration cycle.

[0056] Figure 3 This is a schematic diagram of another self-cascade refrigeration system provided in an embodiment of the present invention. Figure 4 This is a circuit structure block diagram of a self-cascading system provided in an embodiment of the present invention. Optionally, based on the above embodiment, refer to... Figure 3The expansion branch includes: a first solenoid valve 12, a first pressure detection unit 13, a second solenoid valve 14, a second pressure detection unit 15, and an expansion container 16; wherein, the first solenoid valve 12 is connected to the first output end of the gas-liquid separator 4 and the expansion container 16 respectively, and the second solenoid valve 14 is connected to the expansion container 16 and the compressor 1 respectively; the first pressure detection unit 13 is disposed between the first solenoid valve 12 and the gas-liquid separator 4, and the second pressure detection unit 15 is disposed between the second solenoid valve 14 and the compressor 1; wherein, the first pressure detection unit 13 is used to detect the pressure on the high-pressure side of the system, and the second pressure detection unit 15 is used to detect the pressure on the low-pressure side of the system; wherein, the first solenoid valve 12 is used to open when the pressure on the high-pressure side is greater than a first preset pressure; the second solenoid valve 14 is used to open when the pressure on the low-pressure side is less than a second preset pressure; the expansion container 16 is used to store refrigerant.

[0057] The first solenoid valve 12 and the first pressure detection unit 13 are located on the high-pressure side, while the second solenoid valve 14 and the second pressure detection unit 15 are located on the low-pressure side. The first pressure detection unit 13 detects the pressure on the high-pressure side of the system and sends the data to the control module 30, while the second pressure detection unit 15 detects the pressure on the low-pressure side of the system and sends the data to the control module 30.

[0058] The specific values ​​of the first preset pressure and the second preset pressure can be set according to the actual situation, and no specific limitation is made here.

[0059] The first pressure detection unit 13 and the second pressure detection unit 15 can be pressure sensors.

[0060] Optionally, the control module is also configured to: in temperature mode, when the pressure on the high-pressure side is greater than the first preset pressure, control the first solenoid valve to open so as to store the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator into the expansion container; and when the pressure on the low-pressure side is less than the second preset pressure, control the second solenoid valve to open so as to release the gaseous low-boiling-point refrigerant stored in the expansion container into the system so as to regulate the exhaust temperature and exhaust pressure of the compressor.

[0061] For constant temperature and humidity chambers, when repeated high-temperature cooling and low-temperature heating are required, the compressor discharge pressure becomes high during cooling, resulting in a high compressor discharge temperature. This situation severely affects the compressor's reliability. Therefore, by setting up and controlling an expansion branch, the system pressure and temperature can be regulated to prevent excessively high compressor discharge pressure and temperature from affecting compressor reliability. Specifically, in temperature mode, when the first pressure detection unit 13 detects that the pressure on the high-temperature side of the system exceeds a first preset pressure, the control module 30 controls the first solenoid valve to open, causing a portion of the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator 4 to be stored in the expansion container 16. This reduces the amount of low-boiling-point refrigerant in the refrigeration cycle system, thereby lowering the pressure on the high-pressure side of the system and preventing high discharge temperature and pressure of the compressor 1 due to high pressure on the high-pressure side. When the second pressure detection unit detects that the pressure on the low-temperature side of the system is less than the second preset pressure, it indicates that the temperature in the system has dropped to a low temperature. At this time, the control module 30 controls the second solenoid valve 14 to open, so that the low-boiling-point refrigerant stored in the expansion container 16 flows out into the circulation system through the second solenoid valve 14, thereby condensing in the second heat exchanger 5, and then entering the evaporator 9 for cooling after being throttled by the first throttling component 6.

[0062] Optionally, the control module is also configured to: during the process of switching from temperature mode to humidity mode, when the pressure on the high-pressure side is greater than the first preset pressure, control the first solenoid valve to open so as to store the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator into the expansion container, until the pressure on the high-pressure side is less than the first preset pressure, and then control the first solenoid valve to close.

[0063] During the switch from temperature mode to humidity mode, specifically at the beginning of humidity adjustment, the system is already in humidity mode. In humidity mode, the first throttling component 6 is closed, and the first output of the second heat exchanger 5 cannot flow. Therefore, the gaseous low-boiling-point refrigerant separated in the gas-liquid separator 4 cannot enter the second heat exchanger 5 for condensation and heat exchange, leading to a sharp increase in the system's high-pressure side pressure. Therefore, this invention can regulate the system's high-pressure side pressure by setting an expansion branch, thereby preventing excessively high compressor discharge pressure and temperature. Specifically, when the first pressure detection unit 13 detects that the high-pressure side pressure is greater than the first preset pressure, the control module controls the first solenoid valve 12 to open, allowing the gaseous low-boiling-point refrigerant output from the first output of the gas-liquid separator 4 to be stored in the expansion container 16 through the first solenoid valve 12, thereby reducing the system's high-pressure side pressure. The control module 30 then controls the first solenoid valve 12 to close when the high-pressure side pressure is less than the first preset pressure. Therefore, when switching from temperature mode to humidity mode, the pressure of the system can be adjusted by regulating the expansion branch, thereby regulating the compressor's discharge pressure and temperature. This prevents the compressor's discharge pressure and temperature from becoming too high, which could affect the compressor's reliability and ensure the safe and reliable operation of the system.

[0064] Optionally, the control module is also configured to: during the process of switching from humidity mode to temperature mode, when the pressure on the low-pressure side is less than the second preset pressure, control the second solenoid valve to open so as to release the gaseous low-boiling-point refrigerant stored in the expansion container into the system.

[0065] During the switch from humidity mode to temperature mode, because the first throttling component 6 is closed in the previous humidity mode, the gaseous low-boiling-point refrigerant separated by the gas-liquid separator 4 cannot exchange heat through the second heat exchanger 5 and enter the evaporator 9 through the first throttling component 6. When the pressure on the high-pressure side of the system is higher than the first preset pressure, the gaseous low-boiling-point refrigerant can only be stored in the expansion container through the expansion branch. When switching to temperature mode, the pressure on the low-pressure side of the system decreases because the low-boiling-point refrigerant is stored in the expansion container. At this time, the system pressure can be adjusted by adjusting the expansion branch. Specifically, when the second pressure detection unit detects that the pressure on the low-pressure side of the system is lower than the second preset pressure, the control module controls the second solenoid valve to open, so as to release the gaseous low-boiling-point refrigerant stored in the expansion container into the refrigeration cycle system, thereby increasing the amount of low-boiling-point refrigerant in the second heat exchanger, thereby increasing the amount of low-boiling-point refrigerant entering the evaporator 9 and achieving rapid cooling.

[0066] Figure 5 This is a schematic diagram of refrigerant flow under the temperature mode provided in an embodiment of the present invention. Optionally, refer to... Figure 5In temperature mode, compressor 1 compresses the mixed refrigerant into a high-temperature, high-pressure gaseous mixed refrigerant, which is then output to oil separator 2 to separate the entrained refrigeration oil. The oil then returns to the compressor via the oil separator 2's return oil line. The high-temperature, high-pressure gaseous mixed refrigerant separated from oil separator 2 enters the first heat exchanger 3 for heat exchange. In the first heat exchanger 3, the high-boiling-point refrigerant condenses into a liquid refrigerant after heat exchange, while the low-boiling-point refrigerant is difficult to condense in the first heat exchanger 3 and remains a gaseous refrigerant. Thus, the first heat exchanger 3 outputs a gas-liquid two-phase mixed refrigerant. The gas-liquid two-phase mixed refrigerant from the first heat exchanger 3 enters the gas-liquid separator 4. In the gas-liquid separator 4, the liquid high-boiling-point refrigerant and the gaseous low-boiling-point refrigerant are separated. In this process, the liquid high-boiling-point refrigerant is separated at the bottom of the gas-liquid separator 4 and then flows out from the bottom pipe. It enters the second heat exchanger 5 through the second throttling component 7 (in temperature mode, the third throttling component 8 is closed, and no refrigerant passes through). It evaporates and absorbs heat on the low-temperature side of the second heat exchanger 5, becoming a gaseous high-boiling-point refrigerant that flows out from the second output end of the second heat exchanger 5. The gaseous low-boiling-point refrigerant is separated by the gas-liquid separator 4 and flows out from the top of the gas-liquid separator 4 into the high-temperature side of the second heat exchanger 5 for heat exchange. It releases heat and condenses into a liquid low-boiling-point refrigerant, which then flows out from the second heat exchanger 5. After being throttled by the first throttling component 6, it enters the evaporator 9 for heat exchange to generate cooling capacity, thus becoming a gaseous low-boiling-point refrigerant. In temperature mode, the first valve 10 is open, allowing the gaseous low-boiling-point refrigerant from the evaporator 9 to flow through it and mix with the gaseous high-boiling-point refrigerant output from the second output terminal of the second heat exchanger 5 before returning to the compressor 1 suction port, thus completing the refrigeration cycle. For constant temperature and humidity chambers, when repeated high-temperature cooling and low-temperature heating are required, the compressor discharge pressure and temperature can be high during cooling, severely impacting compressor reliability. Therefore, by setting and controlling an expansion branch, the system pressure and temperature can be regulated to prevent excessively high compressor discharge pressure and temperature from affecting compressor reliability. Specifically, when the first pressure detection unit 13 detects that the pressure on the high-temperature side of the system is greater than the first preset pressure, the control module 30 controls the first solenoid valve 12 to open, so that part of the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator 4 is stored in the expansion container 16. In this way, the low-boiling-point refrigerant in the refrigeration cycle system will be reduced, thereby reducing the pressure on the high-pressure side of the system and avoiding the situation where the discharge temperature and discharge pressure of the compressor 1 are high due to the high pressure on the high-pressure side of the system.When the second pressure detection unit detects that the pressure on the low-temperature side of the system is less than the second preset pressure, it indicates that the system temperature has dropped to a low temperature. At this time, the control module 30 controls the second solenoid valve 14 to open, allowing the low-boiling-point refrigerant stored in the expansion container 16 to flow out into the circulation system through the second solenoid valve 14, where it condenses in the second heat exchanger 5. Then, after being throttled by the first throttling component 6, it enters the evaporator 9 for refrigeration. This enables temperature-mode control to achieve the refrigeration cycle, and in temperature mode, it automatically detects the system pressure. When high temperature and high pressure occur, the system pressure and temperature can be automatically adjusted through the expansion branch, thereby avoiding excessively high exhaust temperature and pressure of the compressor in the high-temperature zone, which would affect the reliability of the compressor and ensure the safe, efficient, and reliable operation of the system.

[0067] Figure 6 This is a schematic diagram of refrigerant flow under humidity mode provided in an embodiment of the present invention. Optionally, based on the above embodiments, refer to... Figure 6 The control module is also configured to control the system to operate in humidity mode by controlling the third throttling component 8 and the second valve 11 to open, and the first throttling component 6 and the first valve 10 to close.

[0068] When humidity mode is required, the control module 30 controls the third throttling component 8 and the second valve 11 to open, while the first throttling component 6 and the first valve 10 are closed, thus controlling the system to operate in humidity mode. In humidity mode, because the third throttling component 8 is open and the second throttling component 7 is closed, the high-boiling-point refrigerant separated in the gas-liquid separator 4 enters the evaporator 9 for dehumidification after being throttled by the third throttling component 8. Because the first valve 10 is closed and the second valve 11 is open, the high-boiling-point refrigerant output from the evaporator 9 can only return to the compressor 1 suction port through the second valve 11. The second valve 11 can adjust the evaporation pressure in the evaporator 9 to a suitable pressure (the specific pressure to be adjusted can be set according to the actual situation, and is not specifically limited here), to prevent the evaporation temperature in the evaporator 9 from being too low, which would cause frost to form on the surface of the evaporator 9.

[0069] Optionally, the control module is also configured to: in humidity mode, when the system temperature and humidity meet preset conditions, control the second throttling component to open, so that the liquid high-boiling-point refrigerant output from the first output end of the gas-liquid separator mixes with the high-temperature gaseous high-boiling-point refrigerant output from the evaporator, so as to regulate the compressor's discharge temperature and discharge pressure.

[0070] The preset condition is a high temperature and high humidity situation, that is, a situation with relatively high temperature and high humidity. The specific temperature and humidity values ​​can be set according to the actual situation, and no specific limit is set here.

[0071] refer toFigure 6 In humidity mode, the first throttling component 6 and the first valve 10 are closed, while the third throttling component 8 and the second valve 11 are open. When humidity is applied, the first throttling component 6 is closed, preventing the gaseous low-boiling-point refrigerant separated in the gas-liquid separator 4 from entering the second heat exchanger for condensation. This causes a sharp increase in pressure on the high-pressure side of the system. When the first pressure detection unit 13 detects that the pressure on the high-pressure side is greater than the first preset pressure, the control module controls the first solenoid valve 12 to open, thereby introducing the non-condensable gaseous low-boiling-point refrigerant into the expansion container 16 until the pressure on the high-pressure side is less than the first preset pressure, at which point the first solenoid valve 12 closes. Because the second throttling component 7 is closed and the third throttling component 8 is open, the liquid high-boiling-point refrigerant separated in the gas-liquid separator 4 will be throttled by the third throttling component 8 and enter the evaporator 9 for dehumidification. Furthermore, because the first valve 10 is closed and the second valve 11 is open, the high-boiling-point refrigerant output from the evaporator 9 can only return to the suction port of the compressor 1 through the second valve 11. When the ambient temperature and humidity are high, the temperature of the gaseous high-boiling-point refrigerant output from evaporator 9 is too high. If it returns directly to the compressor suction port, it can easily lead to excessively high compressor suction temperature, resulting in excessively high compressor discharge temperature and pressure, thus affecting the compressor's reliability. In this case, the control module controls the second throttling component 7 to open. After the second throttling component 7 opens, a portion of the liquid high-boiling-point refrigerant separated from gas-liquid separator 4 flows from the second throttling component 7 into the second heat exchanger 5. It then flows directly out through the second output end of the second heat exchanger 5 and mixes with the gaseous high-boiling-point refrigerant flowing out from the second valve 11. The advantages of this setup are: firstly, the portion of liquid high-boiling-point refrigerant separated from gas-liquid separator 4 flows from the second throttling component 7 into the second heat exchanger 5, reducing the amount of high-boiling-point refrigerant flowing into evaporator 9 from the third throttling component 8, thereby helping to reduce system pressure and temperature, and further reducing the compressor's discharge temperature and pressure. On the other hand, since the first throttling component 6 is closed in humidity mode, the second heat exchanger 5 cannot exchange heat. When the second throttling component 7 is opened, the liquid high-boiling-point refrigerant separated from the gas-liquid separator 4 will flow from the second throttling component 7 into the second heat exchanger 5. The liquid high-boiling-point refrigerant cannot exchange heat in the second heat exchanger 5, but flows directly out from the second output end of the second heat exchanger 5 (at this time, the second heat exchanger 5 is equivalent to providing a pipeline), and mixes with the high-temperature gaseous high-boiling-point refrigerant flowing out from the second valve 11, thereby reducing the temperature of the high-temperature gaseous high-boiling-point refrigerant, thereby reducing the temperature of the refrigerant at the compressor suction port, reducing the compressor discharge temperature and discharge pressure, avoiding the compressor suction overheating from affecting its reliability, and ensuring the safe, efficient and reliable operation of the system.

[0072] Figure 7This is a flowchart illustrating a control method for a self-cascading refrigeration system provided in an embodiment of the present invention. The present invention also provides a control method for a self-cascading refrigeration system, such as... Figure 7 As shown, the method includes the following steps:

[0073] S110, The system operates by controlling the opening or closing of the first throttling assembly, the second throttling assembly, the third throttling assembly, the first valve, and the second valve.

[0074] The operating modes include temperature mode and humidity mode.

[0075] S120. During temperature mode and the switching between temperature mode and humidity mode, the compressor's exhaust temperature and exhaust volume are adjusted by regulating the expansion branch.

[0076] S130. In humidity mode, the compressor's exhaust temperature and exhaust pressure are adjusted by controlling the second throttling component.

[0077] The technical solution of this embodiment provides a control method for a self-cascading refrigeration system. This control method includes: controlling the opening or closing of a first throttling component, a second throttling component, a third throttling component, a first valve, and a second valve to control the system's operating mode; wherein the operating mode includes a temperature mode and a humidity mode; and during the temperature mode and the switching between temperature and humidity modes, adjusting the compressor's discharge temperature and discharge pressure by regulating the expansion branch; in the humidity mode, controlling the compressor's discharge temperature and discharge pressure by controlling the second throttling component. Therefore, by setting the first throttling component, the second throttling component, the third throttling component, the first valve, the second valve, and the expansion branch, the temperature and humidity modes of the refrigeration system can be controlled, enabling the self-cascading refrigeration system to be applied to the refrigeration system and dehumidification of environmental test chambers. Furthermore, during the switching between temperature mode and temperature and humidity modes, the compressor's discharge temperature and pressure are adjusted by regulating the expansion branch. In humidity mode, the compressor's discharge temperature and pressure are adjusted by controlling the second throttling component. This avoids excessively high discharge pressure and temperature, preventing damage to the compressor, improving compressor reliability, and ensuring the safe, efficient, and reliable operation of the system. As a result, the self-cascade refrigeration system can not only avoid high discharge pressure and temperature in the high-temperature zone of the environmental chamber, but also control humidity, thereby reducing the complexity of the refrigeration system and requiring less space.

[0078] The self-cascading refrigeration system provided in the embodiments of the present invention can execute the control method of the self-cascading refrigeration system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0079] This invention also provides a constant temperature and humidity environment chamber, which includes the self-cascade refrigeration system described in any embodiment of this invention.

[0080] The constant temperature and humidity environment chamber includes the self-cascade refrigeration system provided in any embodiment of this invention. This self-cascade refrigeration system, through the configuration of a first throttling component, a second throttling component, a third throttling component, a first valve, a second valve, and an expansion branch, can achieve the selection and control of the system's operating mode, applying the self-cascade refrigeration system to both refrigeration and dehumidification. Furthermore, during the switching between temperature mode and temperature / humidity mode, the discharge temperature and pressure of the compressor are adjusted by regulating the expansion branch. In humidity mode, the discharge temperature and pressure of the compressor are adjusted by controlling the second throttling component. This prevents excessively high discharge pressure and temperature, avoiding damage to the compressor, improving compressor reliability, and ensuring the safe, efficient, and reliable operation of the system. Therefore, the self-cascade refrigeration system can not only be used in high-temperature areas without excessive discharge pressure and temperature, but also for humidity applications. Consequently, the self-cascade refrigeration system can be applied to the constant temperature and humidity environment chamber, replacing the original complex bipolar cascade refrigeration system.

[0081] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0082] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A self-cascade cooling system, characterized in that, include: The compressor, first heat exchanger, gas-liquid separator, second heat exchanger, first throttling assembly, second throttling assembly, third throttling assembly, evaporator, first valve, second valve, expansion branch, and control module; The compressor is connected to the first heat exchanger, and the first heat exchanger is connected to the input end of the gas-liquid separator; the first output end of the gas-liquid separator is connected to the first input end of the second heat exchanger, and the second output end of the gas-liquid separator is connected to the second throttling component and the third throttling component, respectively. The first output terminal of the second heat exchanger is connected to the first throttling component, the first input terminal of the second heat exchanger is connected to the second throttling component, and the second output terminal of the second heat exchanger is connected to the first valve, the second valve, and the compressor, respectively. The input end of the evaporator is connected to the first throttling assembly and the third throttling assembly respectively, and the output end of the evaporator is connected to the first valve and the second valve respectively; the expansion branch is connected to the first output end of the gas-liquid separator and the compressor respectively. The control module is electrically connected to at least the first throttling component, the second throttling component, the third throttling component, the first valve, the second valve, and the expansion branch. The control module is configured to control the operating mode of the system by controlling the opening or closing of the first throttling component, the second throttling component, the third throttling component, the first valve, and the second valve; wherein the operating mode includes a temperature mode and a humidity mode; During the temperature mode and the switching between the temperature mode and the humidity mode, the exhaust temperature and exhaust pressure of the compressor are adjusted by adjusting the expansion branch; in the humidity mode, the exhaust temperature and exhaust pressure of the compressor are adjusted by controlling the second throttling component.

2. The self-cascade cooling system according to claim 1, characterized in that, The control module is further configured to control the system to operate in the temperature mode by controlling the first throttling component, the second throttling component, and the first valve to open, and the third throttling component and the second valve to close.

3. The self-cascade cooling system according to claim 2, characterized in that, The expansion branch includes: a first solenoid valve, a first pressure detection unit, a second solenoid valve, a second pressure detection unit, and an expansion container; wherein, the first solenoid valve is connected to the first output end of the gas-liquid separator and the expansion container respectively, and the second solenoid valve is connected to the expansion container and the compressor respectively; the first pressure detection unit is disposed between the first solenoid valve and the gas-liquid separator, and the second pressure detection unit is disposed between the second solenoid valve and the compressor; The first pressure detection unit is used to detect the pressure on the high-pressure side of the system, and the second pressure detection unit is used to detect the pressure on the low-pressure side of the system. The first solenoid valve is used to open when the pressure on the high-pressure side is greater than a first preset pressure; the second solenoid valve is used to open when the pressure on the low-pressure side is less than a second preset pressure; and the expansion container is used to store refrigerant.

4. The self-cascade cooling system according to claim 3, characterized in that, The control module is further configured to: in the temperature mode, when the pressure on the high-pressure side is greater than the first preset pressure, control the first solenoid valve to open so as to store the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator into the expansion container; and when the pressure on the low-pressure side is less than the second preset pressure, control the second solenoid valve to open so as to release the gaseous low-boiling-point refrigerant stored in the expansion container into the system, thereby adjusting the exhaust temperature and exhaust pressure of the compressor.

5. The self-cascade cooling system according to claim 3, characterized in that, The control module is further configured to: during the process of switching from the temperature mode to the humidity mode, when the pressure on the high-pressure side is greater than the first preset pressure, control the first solenoid valve to open so as to store the gaseous low-boiling-point refrigerant output from the first output end of the gas-liquid separator into the expansion container, until the pressure on the high-pressure side is less than the first preset pressure, and then control the first solenoid valve to close.

6. The self-cascade cooling system according to claim 3, characterized in that, The control module is also configured to: during the process of switching from the humidity mode to the temperature mode, when the pressure on the low-pressure side is less than the second preset pressure, control the second solenoid valve to open so as to release the gaseous low-boiling-point refrigerant stored in the expansion container into the system.

7. The self-cascade cooling system according to claim 1, characterized in that, The control module is further configured to control the system to operate in the humidity mode by controlling the third throttling component and the second valve to open, and the first throttling component and the first valve to close.

8. The self-cascade cooling system according to claim 7, characterized in that, The control module is also configured to: in the humidity mode, when the temperature and humidity of the system meet preset conditions, control the second throttling component to open, so that the liquid high-boiling-point refrigerant output from the first output end of the gas-liquid separator mixes with the high-temperature gaseous high-boiling-point refrigerant output from the evaporator, so as to adjust the exhaust temperature and exhaust pressure of the compressor.

9. A control method applied to the self-cascade refrigeration system as described in any one of claims 1-8, characterized in that, include: The operating mode of the system is controlled by opening or closing the first throttling component, the second throttling component, the third throttling component, the first valve, and the second valve; wherein the operating mode includes a temperature mode and a humidity mode; During the temperature mode and the switching between the temperature mode and the humidity mode, the exhaust temperature and exhaust of the compressor are adjusted by adjusting the expansion branch; in the humidity mode, the exhaust temperature and exhaust pressure of the compressor are adjusted by controlling the second throttling component.

10. A constant temperature and humidity environment chamber, characterized in that, Including the self-cascade cooling system as described in any one of claims 1-8.

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