Refrigerant cycle system, cycle method, and air conditioner

Abstract

The application discloses a refrigerant circulation system, a circulation method and an air conditioner. The flash evaporator is connected in parallel to the enthalpy-increasing auxiliary circulation pipeline. When the enthalpy-injection control is started, the main circulation pipeline is not affected. The injection device is arranged between the flash evaporator and the evaporator. The liquid refrigerant in the flash evaporator is injected into the evaporator by the injection device. On one hand, the pressure in the flash evaporator and the amount of liquid refrigerant are reduced. The injection amount of the injection device is controlled, so that the pressure in the flash evaporator is stable, which is beneficial to improving the air supplement stability. On the other hand, the medium-temperature and medium-pressure refrigerant in the flash evaporator is injected into the low-temperature and low-pressure evaporator, which is beneficial to delaying the frosting of the evaporator.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more particularly to a refrigerant circulation system, circulation method, and air conditioner. Background Technology

[0002] Current air conditioning systems all contain compressors, which provide power for the refrigerant circulation.

[0003] However, when the compressor is in a low-temperature environment and used for heating, the specific volume of the refrigerant increases, and the compressor's intake volume decreases sharply, making it difficult to meet the heating requirements.

[0004] In related technologies, an enthalpy-increasing structure is set up to replenish the compressor with gas and increase its enthalpy. However, the current flash tank enthalpy-increasing structure is only connected to the compressor's intermediate pressure chamber and allows it to replenish gas naturally. This will result in very unstable pressure in the enthalpy-increasing structure, which will also lead to unstable gas replenishment to the compressor. At the same time, the current enthalpy-increasing system has a dual throttling valve series structure, which will cause flash loss when the enthalpy-increasing operation is not turned on.

[0005] Therefore, improving the gas replenishment stability of the enthalpy-increasing structure in the circulation system and avoiding flash loss have become urgent problems that need to be addressed in existing technologies. Summary of the Invention

[0006] This application aims to provide an enthalpy-increasing air conditioning system and an enthalpy-increasing method to solve the problem of how to improve the gas replenishment stability of the enthalpy-increasing structure in the circulation system.

[0007] In a first aspect, this application provides a refrigerant circulation system, comprising:

[0008] The main circulation pipeline includes a compressor, a condenser, a main control valve, and an evaporator arranged along a first direction; wherein, the first direction is the flow direction of the refrigerant in the main circulation pipeline when the refrigerant circulation system is in heating mode.

[0009] The auxiliary circulation pipeline includes a flash evaporator, which has a refrigerant inlet, a first refrigerant outlet, and a second refrigerant outlet. The refrigerant inlet is connected to the refrigerant output end of the condenser, the first refrigerant outlet is connected to the enthalpy-increasing port of the compressor, and the second refrigerant outlet is connected to the refrigerant input end of the evaporator.

[0010] An injection device is disposed between the second refrigerant outlet and the refrigerant inlet of the evaporator, and is used to inject refrigerant from the second refrigerant outlet onto the refrigerant inlet of the evaporator.

[0011] In some embodiments of this application, an auxiliary control valve is provided between the refrigerant inlet and the refrigerant output end of the condenser. The auxiliary control valve is configured to close when the injection device injects refrigerant.

[0012] In some embodiments of this application, the main control valve and the auxiliary control valve are connected in parallel.

[0013] In some embodiments of this application, the refrigerant circulation system further includes a temperature sensor for detecting the ambient temperature and a first temperature of the evaporator. When the difference between the ambient temperature and the first temperature is greater than a first preset temperature, the injection device starts injection; when the difference between the ambient temperature and the first temperature is less than a second preset temperature, the injection device stops injection.

[0014] In some embodiments of this application, the flash evaporator is used to form a liquid portion and a gaseous portion of the refrigerant; wherein the gaseous portion can flow out along the first refrigerant outlet, and the liquid portion can flow out along the second refrigerant outlet.

[0015] In some embodiments of this application, a liquid level sensor is provided in the flash evaporator. The liquid level sensor is used to detect the liquid level height of the liquid portion in the flash evaporator, and when the liquid level height is lower than a preset height, the injection device stops injecting refrigerant.

[0016] In some embodiments of this application, the second refrigerant outlet is located at the bottom of the flash evaporator.

[0017] Secondly, this application also provides a refrigerant circulation method, which is applied to the aforementioned refrigerant circulation system, and the refrigerant circulation method is as follows:

[0018] Obtain the first liquid level of the refrigerant in the flash evaporator;

[0019] Compare the first liquid level with the first preset height. When the first liquid level is greater than the first preset height, the injection device starts to inject refrigerant.

[0020] Comparing the first liquid level with the second preset height, when the first liquid level is less than the second preset height, the spraying device stops spraying refrigerant;

[0021] The second preset height is smaller than the first preset height.

[0022] In some embodiments of this application, the refrigerant circulation method further includes:

[0023] Obtain the first difference between the ambient temperature and the first temperature of the evaporator;

[0024] The first difference is compared with the first preset temperature; when the first difference is greater than the first preset temperature, the injection device starts to inject refrigerant.

[0025] The first difference and the second preset temperature are compared; when the first difference is less than the second preset temperature, the injection device stops injecting refrigerant.

[0026] The second preset temperature is lower than the first preset temperature.

[0027] In some embodiments of this application, the refrigerant circulation method further includes:

[0028] Obtain the first duration for which the injection device starts injecting refrigerant;

[0029] The first duration is compared with the preset duration. If the first duration is longer than the preset duration, the injection device stops injecting refrigerant.

[0030] Thirdly, this application also provides an air conditioner including the aforementioned refrigerant circulation system.

[0031] This application provides a refrigerant circulation system, circulation method, and air conditioner. In this refrigerant circulation system, a flash evaporator is installed on the auxiliary circulation pipeline, so that adjusting the internal pressure of the flash evaporator will not affect the main circulation pipeline. By installing an injection device between the flash evaporator and the evaporator, the refrigerant in the flash evaporator can be injected onto the evaporator. On the one hand, this can reduce the internal pressure of the flash evaporator, and by controlling the injection amount of the injection device, the internal pressure of the flash evaporator can be stabilized, which is beneficial to improving the stability of gas injection. On the other hand, injecting the medium-temperature, medium-pressure refrigerant in the flash evaporator into the low-temperature, low-pressure evaporator helps to delay the frosting of the evaporator. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a structural block diagram of a refrigerant circulation system provided in one embodiment of the present invention;

[0034] Figure 2 This is a structural block diagram of a refrigerant circulation system provided in another embodiment of the present invention;

[0035] Figure 3 This is a piping structure diagram of a refrigerant circulation system provided in one embodiment of the present invention;

[0036] Figure 4 This is a flowchart illustrating the steps of a refrigerant circulation method provided in one embodiment of the present invention.

[0037] Explanation of main element symbols:

[0038] 1-Compressor, 2-Four-way valve, 3-Condenser, 4-Main control valve, 5-Evaporator, 6-Gas-liquid separator, 7-Auxiliary control valve, 8-Flash evaporator, 9-Enthalpy control valve, 10-Injection device, 11-Ambient temperature sensor, 12-Defrosting temperature sensor, 13-Liquid level sensor, a-First direction. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention. In the description of the present invention, the meaning of "multiple" includes two or more, unless otherwise explicitly specified.

[0040] In this application, the term "exemplary" is used to mean "serving as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other embodiments, known structures and processes are not described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles disclosed in this application.

[0041] It should be noted that most flash evaporators are currently installed on the main circulation line, and the flash evaporator outlet is connected to the compressor to form an auxiliary circulation line, through which gas is supplied to the flash evaporator. Because the flash evaporator is located on the main circulation line, the refrigerant flow rate within the flash evaporator cannot be controlled, resulting in a highly unstable gas supply process; furthermore, current technology does not consider the issue of evaporator frosting easily in low-temperature environments.

[0042] Therefore, this application improves upon the traditional refrigerant circulation system.

[0043] Please combine Figure 1 , Figure 1A structural block diagram of the refrigerant circulation system in this embodiment is shown; this embodiment is a refrigerant circulation system, which includes a main circulation pipeline, an auxiliary circulation pipeline and an injection device 10.

[0044] A compressor 1, a condenser 3, a main control valve 4, and an evaporator 5 are installed along the main circulation pipeline in the first direction a. The first direction a refers to the flow direction of the refrigerant in the main circulation pipeline when the refrigerant circulation system is in heating mode.

[0045] In other words, compressor 1, condenser 3 and evaporator 5 are connected by pipes, and refrigerant is transferred through the pipes, so that the refrigerant flows between compressor 1, condenser 3 and evaporator 5 to realize the heating or cooling function of the main circulation system.

[0046] The auxiliary circulation pipeline includes a flash evaporator 8. The flash evaporator 8 has a refrigerant inlet, a first refrigerant outlet, and a second refrigerant outlet. The refrigerant inlet is connected to the refrigerant output terminal of the condenser 3, the first refrigerant outlet is connected to the enthalpy-increasing port of the compressor 1, and the second refrigerant outlet is connected to the refrigerant input terminal of the evaporator 5.

[0047] An injection device 10 is disposed between the second refrigerant outlet and the refrigerant inlet of the evaporator 5. The injection device 10 is used to inject refrigerant from the second refrigerant outlet onto the refrigerant inlet of the evaporator 5.

[0048] In the prior art, since the flash evaporator 8 is directly connected to the main circulation pipeline, two of its three ports are connected to the main circulation pipeline, and the remaining port is connected to the compressor 1. Therefore, the pressure inside the flash evaporator 8 depends on the refrigerant flow rate of the main circulation pipeline; the flash evaporator 8 cannot self-regulate its internal pressure, resulting in an unstable enthalpy-increasing medium flow rate output by the flash evaporator 8.

[0049] In the embodiments of this application, the flash evaporator 8 is installed on the auxiliary circulation pipeline. The pressure of the flash evaporator 8 can be controlled by the flow rate on the auxiliary circulation pipeline, and adjusting the pressure of the flash evaporator 8 will not affect the main circulation pipeline. At the same time, an injection device 10 is provided between the flash evaporator 8 and the evaporator 5. The injection device 10 can spray the refrigerant in the flash evaporator 8 onto the evaporator 5. On the one hand, this can reduce the internal pressure of the flash evaporator 8, and by controlling the injection amount of the injection device 10, the internal pressure of the flash evaporator 8 can be stabilized, which is beneficial to improving the stability of enthalpy increase and gas replenishment. On the other hand, spraying the medium-temperature and medium-pressure refrigerant in the flash evaporator 8 into the low-temperature and low-pressure evaporator 5 helps to delay the frosting of the evaporator 5.

[0050] Please refer to the following: Figure 2 , Figure 2The diagram shows a structural block diagram of the refrigerant circulation system in this embodiment. In some embodiments of this application, an auxiliary control valve 7 is provided between the refrigerant inlet and the refrigerant outlet of the condenser 3. The auxiliary control valve 7 can regulate the flow rate of refrigerant into the flash evaporator 8.

[0051] More specifically, the auxiliary control valve 7 is configured to close when the injection device 10 injects refrigerant. At this time, since the auxiliary control valve 7 is closed, the auxiliary circulation pipeline and the main circulation pipeline are disconnected, which helps to solve the problem of liquid return on the enthalpy-increasing side of the auxiliary circulation pipeline.

[0052] In some embodiments, the auxiliary control valve 7 is one of an electronic expansion valve, a capillary valve, or a thermostatic expansion valve.

[0053] In some embodiments of this application, the main control valve 4 is disposed between the condenser 3 and the evaporator 5, and is connected in parallel with the auxiliary control valve 7.

[0054] In the prior art, the flash evaporator 8 is set on the main circulation pipeline. Therefore, the main control valve 4 on the main circulation pipeline and the auxiliary control valve 7 on the auxiliary circulation pipeline are in series. Under the condition of not increasing enthalpy (such as general refrigeration condition and high temperature heating condition), since the main control valve 4 and the auxiliary control valve 7 are mostly electronic expansion valves, they may flash before throttling, resulting in an unavoidable capacity reduction problem.

[0055] In the embodiments of this application, the main control valve 4 and the auxiliary control valve 7 are connected in parallel. On the one hand, the auxiliary circulation pipeline gas supply can be controlled independently, and on the other hand, the problem of refrigerant capacity reduction caused by the two electronic expansion valves being connected in series can be solved.

[0056] In some embodiments, the main control valve 4 is one of an electronic expansion valve, a capillary valve, or a thermostatic expansion valve.

[0057] In some embodiments of this application, the refrigerant circulation system further includes a temperature sensor, which is used to detect the ambient temperature and the first temperature of the evaporator 5. When the difference between the ambient temperature and the first temperature is greater than a first preset temperature, the injection device 10 starts injection; when the difference between the ambient temperature and the second temperature is less than a second preset temperature, the injection device 10 stops injection.

[0058] It is beneficial to heat the evaporator 5 through the refrigerant in the flash evaporator 8 in a low-temperature environment, thereby increasing the temperature of the evaporator 5 and delaying the frosting of the evaporator 5.

[0059] In some embodiments of this application, the flash evaporator 8 is used to form a liquid portion and a gaseous portion of the refrigerant. The gaseous portion flows out along a first refrigerant outlet, and the liquid portion flows out along a second refrigerant outlet.

[0060] The flash evaporator 8 can convert a portion of high-pressure saturated water into saturated water vapor. In this embodiment, the flash evaporator 8 can separate the refrigerant into a two-phase gas-liquid state. The liquid portion in the flash evaporator 8 can be discharged to the evaporator 5 for pressure regulation; the gaseous portion can be discharged to the compressor 1 for enthalpy enhancement.

[0061] In some embodiments, the flash evaporator 8 is a flash tank.

[0062] In some embodiments, an enthalpy-increasing control valve 9 is provided between the flash evaporator 8 and the compressor 1. The enthalpy-increasing control valve 9 can be opened or closed according to the actual operating conditions to select whether to supply gas to the compressor 1 to increase enthalpy.

[0063] In some embodiments of this application, a liquid level sensor 13 is provided in the flash evaporator 8. The liquid level sensor 13 is used to detect the liquid level height in the liquid portion of the flash evaporator 8, and when the liquid level height is lower than a preset height, the injection device 10 stops injecting refrigerant. The amount of refrigerant in the flash evaporator 8 can be controlled by the liquid level sensor 13, thereby controlling the enthalpy increase flow rate.

[0064] In some embodiments, the bottom wall of the flash evaporator 8 can be used as the reference 0 scale, the top wall as the 1 scale, and a percentage value can be displayed between the 0 scale and the 1 scale.

[0065] In some embodiments, the liquid level sensor 13 is a capacitive liquid level sensor 13, which is beneficial to improving the accuracy of liquid level detection.

[0066] In some embodiments of this application, the second refrigerant outlet is located at the bottom of the flash evaporator 8. This prevents the second refrigerant outlet from venting the gaseous portion of the flash evaporator 8.

[0067] Another embodiment of this application also provides a refrigerant circulation system; please refer to the relevant documentation. Figure 3 , Figure 3 The diagram shows the piping structure of the refrigerant circulation system in this embodiment; it includes a compressor 1, a four-way valve 2, a water-side heat exchanger (corresponding to a condenser 3), a main electronic expansion valve (corresponding to a main control valve 4), a finned tube heat exchanger (corresponding to an evaporator 5), a gas-liquid separator 6, an auxiliary electronic expansion valve (corresponding to an auxiliary control valve 7), a flash tank (corresponding to a flash evaporator 8), a solenoid valve (corresponding to an enthalpy increase control valve 9), an injection device 10, an ambient temperature sensor 11, a defrost temperature sensor 12, and a liquid level sensor 13.

[0068] The refrigerant circulation system of this embodiment can be applied to both heating and cooling conditions; specifically:

[0069] When the ambient temperature is higher than the preset value, compressor 1 does not need to increase enthalpy and replenish gas, and the solenoid valve is closed.

[0070] The refrigerant flow direction in its refrigeration mode is: compressor 1 → four-way valve 2 → finned tube heat exchanger → main electronic expansion valve → water-side heat exchanger → four-way valve 2 → gas-liquid separator 6 → compressor 1.

[0071] The refrigerant flow direction in its heating mode is: compressor 1 → four-way valve 2 → water-side heat exchanger → main electronic expansion valve → finned tube heat exchanger → four-way valve 2 → gas-liquid separator 6 → compressor 1.

[0072] Without activating the enthalpy-increasing structure, the refrigerant flows through the main electronic expansion valve, but does not need to flow through the flash tank and auxiliary electronic expansion valve. Therefore, there is no issue of two electronic expansion valves connected in series for flash throttling.

[0073] When the ambient temperature is lower than the preset value, if the compressor is in heating mode, compressor 1 needs to increase enthalpy and replenish gas, and the solenoid valve will open.

[0074] The refrigerant flow direction of the main circulation pipeline in heating mode is as follows: compressor 1 → four-way valve 2 → water-side heat exchanger → split into two via a three-way valve → main electronic expansion valve → finned tube heat exchanger → four-way valve 2 → gas-liquid separator 6 → compressor 1.

[0075] The refrigerant flow direction of the auxiliary circulation pipeline is: water-side heat exchanger → through a three-way valve split into two → auxiliary electronic expansion valve → flash tank → solenoid valve → compressor 1.

[0076] In this process, some of the liquid refrigerant in the flash tank can be sprayed onto the finned tube heat exchanger along the spraying device 10.

[0077] An embodiment of this application is a refrigerant circulation method, which is applied to the aforementioned refrigerant circulation system. Please refer to [link / reference]. Figure 4 The refrigerant circulation method is as follows:

[0078] S100: Obtain the first liquid level of the refrigerant in the flash evaporator 8; specifically, the liquid level height of the liquid portion in the flash evaporator 8 can be detected by the liquid level sensor 13.

[0079] S200: Compare the first liquid level with the first preset height. When the first liquid level is greater than the first preset height, the injection device 10 starts injecting refrigerant. Specifically, the first preset height can be set to 75%-95%Htotal, where Htotal is the depth of the inner cavity of the flash evaporator 8.

[0080] S300: Compare the first liquid level and the second preset height. When the first liquid level is less than the second preset height, the injection device 10 stops injecting refrigerant.

[0081] The second preset height is smaller than the first preset height.

[0082] In some embodiments of this application, the refrigerant circulation method further includes:

[0083] S100': Obtain the first difference between the ambient temperature and the first temperature of the evaporator 5; specifically, an ambient temperature sensor 11 can be set to detect the ambient temperature, and a defrosting temperature sensor 12 can be set to detect the first temperature.

[0084] It is understandable that the formula for calculating the first difference, Tc, is: Tc = T 环 -T 化 .

[0085] S200': Compare the first difference with the first preset temperature; when the first difference is greater than the first preset temperature, the injection device 10 starts to inject refrigerant;

[0086] S300': Compare the first difference and the second preset temperature; when the first difference is less than the second preset temperature, the injection device 10 stops injecting refrigerant;

[0087] The second preset temperature is lower than the first preset temperature.

[0088] Specifically, the first preset temperature is T. C0 -1, the second preset temperature is T C0 -3, where T CO This refers to the temperature difference entering the defrost pipe under corresponding operating conditions. The value varies for different ambient temperature ranges. C0 The temperature is usually 4-10℃.

[0089] In some embodiments of this application, the refrigerant circulation method further includes:

[0090] S100”: The first duration of the injection device 10 starting to inject refrigerant;

[0091] S200”: Compare the first duration with the preset duration. If the first duration is longer than the preset duration, the injection device 10 stops injecting refrigerant.

[0092] If any of the conditions in steps S300, S300', or S200 are met, the injection device 10 can stop injecting refrigerant.

[0093] An embodiment of this application also provides an air conditioner, including the refrigerant circulation system described above.

[0094] It should be noted that the refrigerant circulation system in this embodiment is not limited to the structure of an air conditioner, but can also be applied to non-air source heat pump systems, such as water source heat pumps, screw chillers, centrifugal chillers and other refrigeration or heat pump systems.

[0095] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the detailed descriptions of other embodiments above, which will not be repeated here.

[0096] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0097] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0098] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0099] Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, the numerical parameters should take into account a specified number of significant digits and employ a general method of digit preservation. Although the numerical ranges and parameters used to confirm their breadth of application in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0100] For each patent, patent application, patent application publication, and other material such as articles, books, specifications, publications, and documents referenced in this application, the entire contents of that patent application are incorporated herein by reference, except for historical application documents that are inconsistent with or conflict with the content of this application, and documents that limit the broadest scope of the claims of this application (currently or subsequently appended to this application). It should be noted that if there are any inconsistencies or conflicts between the descriptions, definitions, and / or terminology used in the supplementary materials of this application and the content of this application, the descriptions, definitions, and / or terminology used in this application shall prevail.

[0101] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A refrigerant circulation system, characterized in that, include: The main circulation pipeline includes a compressor, a condenser, a main control valve, and an evaporator arranged along a first direction; wherein, the first direction is the flow direction of the refrigerant in the main circulation pipeline when the refrigerant circulation system is in heating mode. An auxiliary circulation pipeline includes a flash evaporator, which has a refrigerant inlet, a first refrigerant outlet, and a second refrigerant outlet. The refrigerant inlet is connected to the refrigerant output end of the condenser, the first refrigerant outlet is connected to the enthalpy-increasing port of the compressor, and the second refrigerant outlet is connected to the refrigerant input end of the evaporator. The flash evaporator is used to form a liquid portion of the refrigerant, which can flow out along the second refrigerant outlet. An injection device is disposed between the second refrigerant outlet and the refrigerant inlet of the evaporator, and is used to inject refrigerant from the second refrigerant outlet onto the refrigerant inlet of the evaporator.

2. The refrigerant circulation system according to claim 1, characterized in that, An auxiliary control valve is provided between the refrigerant inlet and the refrigerant outlet of the condenser. The auxiliary control valve is configured to close when the injection device injects refrigerant.

3. The refrigerant circulation system according to claim 2, characterized in that, The main control valve and the auxiliary control valve are connected in parallel.

4. The refrigerant circulation system according to claim 1, characterized in that, The refrigerant circulation system also includes a temperature sensor, which is used to detect the ambient temperature and the first temperature of the evaporator. When the difference between the ambient temperature and the first temperature is greater than a first preset temperature, the injection device starts injection; when the difference between the ambient temperature and the first temperature is less than a second preset temperature, the injection device stops injection.

5. The refrigerant circulation system according to claim 1, characterized in that, The flash evaporator is also used to form a gaseous portion of the refrigerant, which can flow out along the first refrigerant outlet.

6. The refrigerant circulation system according to claim 1, characterized in that, The flash evaporator is equipped with a liquid level sensor, which is used to detect the liquid level height of the liquid portion inside the flash evaporator. When the liquid level height is lower than a preset height, the injection device stops injecting refrigerant.

7. The refrigerant circulation system according to claim 1, characterized in that, The second refrigerant outlet is located at the bottom of the flash evaporator.

8. A refrigerant circulation method, characterized in that, The refrigerant circulation method is applied to the refrigerant circulation system according to any one of claims 1-7, and the refrigerant circulation method is as follows: Obtain the first liquid level of the refrigerant in the flash evaporator; Compare the first liquid level with the first preset height. When the first liquid level is greater than the first preset height, the injection device starts to inject refrigerant. Comparing the first liquid level with the second preset height, when the first liquid level is less than the second preset height, the spraying device stops spraying refrigerant; The second preset height is smaller than the first preset height.

9. The refrigerant circulation method according to claim 8, characterized in that, The refrigerant circulation method further includes: Obtain the first difference between the ambient temperature and the first temperature of the evaporator; The first difference is compared with the first preset temperature; when the first difference is greater than the first preset temperature, the injection device starts to inject refrigerant. The first difference and the second preset temperature are compared; when the first difference is less than the second preset temperature, the injection device stops injecting refrigerant. The second preset temperature is lower than the first preset temperature.

10. The refrigerant circulation method according to claim 9, characterized in that, Refrigerant circulation methods also include: Obtain the first duration for which the injection device starts injecting refrigerant; The first duration is compared with the preset duration. If the first duration is longer than the preset duration, the injection device stops injecting refrigerant.

11. An air conditioner, characterized in that, Includes the refrigerant circulation system according to any one of claims 1-7.

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