Air conditioner and control method thereof

Abstract

The present application relates to air conditioning technical field, specifically provide a kind of air conditioner and its control method, it aims at certain degree to solve the problem that existing air conditioner is started compressor when refrigerant is recycled to outdoor heat exchanger, compressor cannot make air conditioner normal operation.The air conditioner of the present application includes the first branch that is connected with refrigerant container and gas-liquid separator entrance and the first on-off valve arranged on it, and its control method includes: in the case where refrigerant has been recycled to outdoor heat exchanger and refrigerant container, selectively make the first on-off valve intermittently in open state;Make control valve in the state that allows refrigerant to flow through.This can discharge the refrigerant in outdoor heat exchanger, so that outdoor heat exchanger has some space to receive gaseous refrigerant from compressor outlet after starting compressor and make most of it into normal temperature high pressure liquid refrigerant, avoid air conditioner cannot normal operation due to outdoor heat exchanger cannot normally function.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, specifically providing an air conditioner and its control method. Background Technology

[0002] During the use of an air conditioner, refrigerant leakage in the indoor unit (i.e., the indoor side of the air conditioner) can endanger the health of occupants and may also pose an explosion risk due to increased refrigerant concentration. To address this, those skilled in the art have designed air conditioners to recover refrigerant from the indoor unit to the outdoor unit, preventing further leakage. Specifically, see [link to relevant documentation]. Figure 1 Air conditioner 1 includes an indoor expansion valve 11, an indoor heat exchanger 12, a gas-liquid separator 13, a compressor 14, an outdoor heat exchanger 15, an outdoor expansion valve 16, and a four-way reversing valve 17. Furthermore, an on / off valve 18 is provided between the indoor expansion valve 11 and the outdoor expansion valve 16. Taking heating mode as an example, if refrigerant leakage occurs on the indoor side of air conditioner 1 while it is in heating mode, the state of the four-way reversing valve 17 is switched to allow air conditioner 1 to enter cooling mode (in cooling mode, the refrigerant flow direction is as follows...). Figure 1 As indicated by the middle arrow, and in Figure 1 The dashed lines inside the four-way reversing valve 17 indicate a closed circuit, and the solid lines indicate a closed circuit. When the on / off valve 18 is closed, the compressor 14 continues to operate. In this way, the refrigerant on the indoor side continuously flows into the outdoor heat exchanger 15 under the action of the compressor 14 and is liquefied. Because the on / off valve 18 is closed, and the highest point of the pipe between the inlet of the outdoor heat exchanger 15 and the outlet of the compressor 14 in cooling mode is higher than the liquid level inside the outdoor heat exchanger 15 after refrigerant recovery, the refrigerant cannot flow back into the indoor side. Therefore, the refrigerant is stored in the outdoor heat exchanger 15 after flowing in. After all the refrigerant in the indoor side, the gas-liquid separator 13, and the compressor 14 has entered the outdoor heat exchanger 15, the compressor 14 is turned off, completing the refrigerant recovery. Although this method avoids more refrigerant leakage indoors, after the leak is repaired, when the compressor is started, the refrigerant often has difficulty circulating normally in the refrigerant circulation loop, and the air conditioner cannot operate normally.

[0003] Therefore, there is a need in the field for a new air conditioner and its control method to solve the above problems. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned technical problems, namely, to a certain extent, the problem that the compressor cannot make the air conditioner operate normally when the compressor is started after the refrigerant is recovered to the outdoor heat exchanger.

[0005] In a first aspect, the present invention provides a control method for an air conditioner, the air conditioner comprising an indoor heat exchanger, a gas-liquid separator, a compressor, an outdoor heat exchanger, and a refrigerant container connected by pipes; the air conditioner further comprises a control valve disposed between the outdoor heat exchanger and the refrigerant container, and located at the end of the outdoor heat exchanger away from the compressor, the control valve being used to control the refrigerant flow rate therethrough, wherein when the control valve is in a state allowing the refrigerant to flow through, the refrigerant in the outdoor heat exchanger can flow into the refrigerant container; the air conditioner further comprises a first branch and a... A first on / off valve is provided on the first branch, the first end of the first branch is connected to the refrigerant container, and the second end of the first branch is connected to the inlet of the gas-liquid separator. When the first on / off valve is in the open state, the refrigerant in the refrigerant container can flow into the gas-liquid separator. The control method includes: when the refrigerant has been recovered to the outdoor heat exchanger and the refrigerant container, selectively and intermittently opening the first on / off valve so that the refrigerant in the refrigerant container flows into the gas-liquid separator; and setting the control valve to allow the refrigerant to flow through.

[0006] With the above technical solution, the refrigerant in the refrigerant container first flows into the gas-liquid separator, leaving space in the refrigerant container to receive refrigerant from the outdoor heat exchanger. After the refrigerant flows out of the outdoor heat exchanger, some space is freed up in the outdoor heat exchanger. In this way, after the compressor is started, the gaseous refrigerant discharged from the compressor outlet can enter the outdoor heat exchanger, so that the outdoor heat exchanger can convert most of it into room temperature high-pressure liquid refrigerant. In other words, the outdoor heat exchanger can function normally at this time, avoiding the air conditioner from failing to operate properly due to the outdoor heat exchanger's inability to function properly.

[0007] In the preferred embodiment of the above-mentioned air conditioner control method, the step of "selectively keeping the first on-off valve in an intermittent open state" specifically includes: keeping the first on-off valve in an intermittent open state by alternating opening and closing.

[0008] In the preferred embodiment of the above-mentioned air conditioner control method, the step of "intermittently keeping the first on-off valve in an alternating opening and closing manner" specifically includes: opening the first on-off valve; obtaining the current liquid level of the gas-liquid separator; determining whether the current liquid level has reached a first preset liquid level; closing the first on-off valve whenever the current liquid level reaches the first preset liquid level, and reopening the first on-off valve when the current liquid level is lower than the first preset liquid level; wherein, the first preset liquid level does not exceed the highest liquid level allowed in the gas-liquid separator.

[0009] When the above technical solution is adopted, the first on-off valve can be closed when the current liquid level reaches the first preset liquid level, promptly stopping the injection of refrigerant into the gas-liquid separator. This prevents the refrigerant in the gas-liquid separator from exceeding its maximum allowable liquid level, which could lead to liquid refrigerant entering the compressor and causing liquid slugging. Furthermore, when the current liquid level is lower than the first preset liquid level, the first on-off valve can be reopened, allowing refrigerant from the refrigerant recovery tank to continue being injected into the gas-liquid separator. This makes fuller use of the space in the gas-liquid separator, thereby discharging as much refrigerant as possible from the refrigerant recovery tank, and consequently, discharging as much refrigerant as possible from the outdoor heat exchanger.

[0010] In a preferred embodiment of the above-mentioned air conditioner control method, the control method further includes: after each closure of the first on / off valve, obtaining the duration of the closure of the first on / off valve; determining whether the duration has reached a preset duration; if the duration has reached the preset duration, obtaining the current liquid level of the gas-liquid separator again and determining whether the current liquid level has reached the first preset liquid level.

[0011] By adopting the above technical solution, the number of times the current liquid level of the gas-liquid separator is obtained is reduced, thereby reducing the workload of the controller and enabling the controller to take on more other control operations.

[0012] In the preferred embodiment of the above-mentioned air conditioner control method, the control valve is the outdoor electronic expansion valve of the air conditioner; the step of "putting the control valve in a state that allows the refrigerant to flow" specifically includes: putting the control valve in the state of maximum opening.

[0013] By adopting the above technical solution, the refrigerant can flow out of the outdoor heat exchanger more quickly, thereby enabling the compressor to start earlier and provide air conditioning functions for users.

[0014] In a preferred embodiment of the above-mentioned air conditioner control method, the control method further includes: when the first on / off valve is in the open state, making the control valve in the state of minimum opening.

[0015] By adopting the above technical solution, a large amount of refrigerant can be prevented from rushing from the outdoor heat exchanger into the refrigerant recovery tank. This results in a relatively low refrigerant flow rate from the refrigerant recovery tank into the gas-liquid separator. Consequently, the disturbance to the refrigerant in the gas-liquid separator is minimized, and the obtained liquid level in the gas-liquid separator will not be artificially high. Furthermore, when the first on-off valve is closed whenever the current liquid level reaches the first preset liquid level, the obtained liquid level in the gas-liquid separator will not be artificially high. This avoids closing the first on-off valve when it is not necessary, which would affect the overall efficiency of refrigerant entering the gas-liquid separator.

[0016] In a preferred embodiment of the above-mentioned air conditioner control method, the air conditioner further includes a second branch and a second on / off valve disposed on the second branch. The second branch connects the inlet end of the compressor and the outlet of the refrigerant container that discharges gaseous refrigerant. The control method further includes: during the process of the compressor being in operation to recover refrigerant into the refrigerant container and the outdoor heat exchanger, the second on / off valve is opened to allow gaseous refrigerant to flow from the refrigerant container into the inlet end of the compressor until the liquid level in the refrigerant container reaches a second preset liquid level; wherein the second preset liquid level does not exceed the maximum allowable liquid level in the refrigerant container.

[0017] When the above technical solution is adopted, keeping the second on / off valve in the open state allows the gaseous refrigerant in the refrigerant recovery tank to flow from the refrigerant recovery tank into the compressor inlet. On the one hand, the gaseous refrigerant is discharged from the refrigerant recovery tank, leaving more space for the storage of liquid refrigerant in the refrigerant recovery tank and reducing the pressure inside the refrigerant recovery tank, allowing the refrigerant recovery tank to store more liquid refrigerant. On the other hand, after the gaseous refrigerant flowing out of the refrigerant recovery tank flows into the compressor inlet, it will re-enter the outdoor heat exchanger to be liquefied, and then enter the refrigerant recovery tank again. This is equivalent to turning the gaseous refrigerant in the refrigerant recovery tank into liquid through recirculation, and then storing it in the refrigerant recovery tank again, saving storage space in the refrigerant recovery tank and allowing the refrigerant recovery tank to store more refrigerant.

[0018] In a preferred embodiment of the above-mentioned air conditioner control method, the air conditioner further includes a third on / off valve disposed between the refrigerant container and the indoor heat exchanger, and the control method further includes: during the process of the compressor being in operation to recover refrigerant into the refrigerant container and the outdoor heat exchanger, the third on / off valve is kept in a closed state.

[0019] When the above technical solution is adopted, the third shut-off valve is in the closed state, so that after the refrigerant enters the refrigerant recovery tank and the outdoor heat exchanger, it cannot flow through the third shut-off valve and thus cannot return to the indoor side of the air conditioner. This allows the refrigerant to be stored in the refrigerant recovery tank and the outdoor heat exchanger, thereby realizing refrigerant recovery.

[0020] In the preferred embodiment of the above-mentioned air conditioner control method, the refrigerant container is the refrigerant recovery tank of the air conditioner.

[0021] In a second aspect, the present invention also provides an air conditioner including a controller configured to perform any of the control methods for an air conditioner as described above. Attached Figure Description

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0023] Figure 1 This is a schematic diagram of the structure of an air conditioner in the prior art;

[0024] Figure 2 This is a schematic diagram of the structure of an embodiment of the air conditioner of the present invention;

[0025] Figure 3 This is a flowchart of the main steps of the air conditioner control method of the present invention;

[0026] Figure 4 This is a flowchart of one embodiment of the air conditioner control method of the present invention.

[0027] Figure label:

[0028] Air conditioner 1;

[0029] Indoor expansion valve 11; Indoor heat exchanger 12; Gas-liquid separator 13; Compressor 14; Outdoor heat exchanger 15; Outdoor expansion valve 16; Four-way reversing valve 17; On / off valve 18;

[0030] Air conditioner 2;

[0031] Indoor expansion valve 201; Indoor heat exchanger 202; Gas-liquid separator 203; Compressor 204; Outdoor heat exchanger 205; Outdoor expansion valve 206; Refrigerant recovery tank 207; Four-way reversing valve 208; First on / off valve 209; Second on / off valve 210; Third on / off valve 211. Detailed Implementation

[0032] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. For example, although this embodiment is described in conjunction with an air conditioner having a four-way reversing valve, this is not intended to limit the scope of protection of this application. Without departing from the principles of this application, those skilled in the art can apply the control method of this application to air conditioners without a four-way reversing valve.

[0033] It should be noted that in the description of this invention, terms such as "top" and "bottom," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. This is merely for ease of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] First, combine Figure 2 The structure of the air conditioner 2 in this invention will be described, such as... Figure 2 As shown, the air conditioner 2 includes an indoor expansion valve 201, an indoor heat exchanger 202, a gas-liquid separator 203, a compressor 204, an outdoor heat exchanger 205, an outdoor expansion valve 206, a refrigerant container, and a four-way reversing valve 208, which are connected by pipes to form a refrigerant circulation main loop. Both the outdoor expansion valve 206 and the indoor expansion valve 201 can control the refrigerant flow rate by changing their opening degree. In this embodiment, the refrigerant container is the refrigerant recovery tank 207 of the air conditioner 2. With the outdoor expansion valve 206 in a state that allows refrigerant flow, the refrigerant in the outdoor heat exchanger 205 can flow into the refrigerant recovery tank 207. Of course, this requires those skilled in the art to reasonably set the height of the outdoor heat exchanger 205, the refrigerant recovery tank 207, and the highest point of the passage between them (including the piping and the flow path in the outdoor expansion valve 206): the height of the outdoor heat exchanger 205 and the refrigerant recovery tank 207 should be set such that the liquid level of the outdoor heat exchanger 205 after refrigerant recovery is completed is higher than the inlet of the refrigerant recovery tank 207, and the highest point of the passage between the outdoor heat exchanger 205 and the refrigerant recovery tank 207 is lower than the liquid level of the outdoor heat exchanger 205 after refrigerant recovery is completed (in...). Figure 2 The air conditioner shown is, according to: Figure 2The outdoor heat exchanger 205 is positioned at the lower open end, i.e., the refrigerant outlet end of the outdoor heat exchanger 205 in cooling mode. The highest point of the passage between the outdoor heat exchanger 205 and the refrigerant recovery tank 207 should be set lower than the liquid level of the outdoor heat exchanger 205 after refrigerant recovery is completed. This ensures that the refrigerant in the outdoor heat exchanger 205 can flow smoothly into the refrigerant recovery tank 207. The gas-liquid separator 203 is equipped with a liquid level detection device (such as a liquid level sensor) for detecting the refrigerant liquid level in the gas-liquid separator 203. The air conditioner 2 also includes a first branch and a first on / off valve 209 installed on the first branch. The first end of the first branch is connected to the refrigerant recovery tank 207, and the second end of the first branch is connected to the inlet of the gas-liquid separator 203. When the first shut-off valve 209 is open, the refrigerant in the refrigerant recovery tank 207 can flow into the gas-liquid separator 203. Of course, this requires those skilled in the art to reasonably set the height of the refrigerant recovery tank 207, the gas-liquid separator 203, and the highest point of the passage between them (including the pipeline and the flow path in the first shut-off valve 209): The height of the refrigerant recovery tank 207 and the gas-liquid separator 203 should be set such that the liquid level of the refrigerant recovery tank 207 after refrigerant recovery is completed is higher than the inlet of the gas-liquid separator 203, and the highest point of the passage between the refrigerant recovery tank 207 and the gas-liquid separator 203 is lower than the liquid level of the refrigerant recovery tank 207 after refrigerant recovery (in...). Figure 2 In the air conditioner shown, the highest point of the first branch and the passage between the inlet of the gas-liquid separator 203 and the second end of the first branch should be set lower than the liquid level of the refrigerant recovery tank 207 after refrigerant recovery. This ensures that when the first shut-off valve 209 is open, the refrigerant in the refrigerant recovery tank 207 can flow smoothly into the gas-liquid separator 203. The air conditioner 2 also includes a second branch and a second shut-off valve 210 installed on the second branch. The first end of the second branch is connected to the inlet of the compressor 204, and the second end of the second branch is connected to an opening formed at the top of the refrigerant recovery tank 207. The air conditioner 2 also includes a third shut-off valve 211 installed between the refrigerant recovery tank 207 and the indoor heat exchanger 202.

[0036] Although the above description uses the refrigerant recovery tank 207, which is already present in the main refrigerant circulation loop of air conditioner 2, as an example, the refrigerant container is not limited to the refrigerant recovery tank 207 already present in air conditioner 2; a flash tank, etc., can also be used. Furthermore, the refrigerant container is not limited to being located on the main refrigerant circulation loop; it can also be located on a branch line, for example, in... Figure 2 Based on this, the refrigerant recovery tank 207 is removed, and the outdoor expansion valve 206 and the third on / off valve 211 are directly connected through a pipeline. Both ends of the refrigerant container can be connected to this pipeline, that is, connected in parallel with this pipeline.

[0037] Although the above description uses the example of the opening on the refrigerant recovery tank 207 for connecting with the second branch being located at the top of the refrigerant recovery tank 207, the location of the opening on the refrigerant recovery tank 207 is not limited to the top. In some alternative embodiments, the opening may also be located at the bottom of the refrigerant recovery tank 207, and the second branch extends upward from the opening to a higher position in the refrigerant recovery tank 207 so as to connect with the gaseous refrigerant in the refrigerant recovery tank 207.

[0038] Although the outdoor expansion valve 206 is used as an example of the control valve in the claims above, it is not mandatory to use the outdoor expansion valve 206 as the control valve. In some alternative embodiments, a separate valve may be provided between the outdoor heat exchanger 205 and the refrigerant container, located at the end of the outdoor heat exchanger 205 away from the compressor 204. In this case, the outdoor expansion valve 206 can be retained, and the separate valve and the outdoor expansion valve 206 can be used together as the control valve. Alternatively, the outdoor expansion valve 206 may be omitted, in which case the separate valve can be used as the control valve. Regarding the structure of the control valve, it is not limited to using a valve that cannot be completely shut off, such as an expansion valve; an on / off valve may also be used.

[0039] As described in the background section, when the air conditioner 2 restarts the compressor 204 after recovering the refrigerant to the outdoor heat exchanger 205, the compressor 204 fails to enable the air conditioner 2 to operate normally. To solve this problem, this application proposes a control method for the air conditioner 2, such as... Figure 3 As shown, the control method includes:

[0040] S1. When the refrigerant has been recovered into the outdoor heat exchanger 205 and the refrigerant recovery tank 207, the first on / off valve 209 is selectively kept intermittently open.

[0041] S2. Set the outdoor expansion valve 206 to a state that allows refrigerant to flow.

[0042] In step S1, the first on-off valve 209 is selectively kept in the open state intermittently. Specifically, the first on-off valve 209 may be kept open for a period of time and then closed. Then, the first on-off valve 209 is not opened again before the compressor 204 is started. Alternatively, the first on-off valve 209 may be kept in the open state intermittently by alternating opening and closing.

[0043] In step S2, the valve is placed in a state that allows refrigerant flow. That is, if the valve was previously in a state that prohibited refrigerant flow, then in step S2, the valve is opened; if the valve was already in a state that allowed refrigerant flow, then in step S2, the valve remains in that state. In this embodiment, since the outdoor expansion valve 206 cannot be completely closed, its opening degree can only be adjusted. Therefore, in step S2, placing the outdoor expansion valve 206 in a state that allows refrigerant flow specifically means keeping the outdoor expansion valve 206 in a state that allows refrigerant flow. Of course, keeping it in a state that allows refrigerant flow can be done with a larger or smaller opening degree or the same as before. It should be noted that for other steps of the control method of the present invention, if the description is "to put a certain component in a certain state", it is similar to the explanation of "to put the valve in a state that allows refrigerant to flow". That is, if the component was previously in a state different from "a certain state", then in this step the component is switched to "a certain state"; if the component was already in "a certain state" before, then in this step the component can continue to maintain that state. This will not be elaborated further below.

[0044] In the control method of the present invention, in step S1, the purpose of opening the first on / off valve 209 is to open the first branch, creating conditions for the refrigerant in the refrigerant recovery tank 207 to enter the gas-liquid separator 203. In step S2, the outdoor expansion valve 206 is in a state that allows the refrigerant to flow through, thus creating conditions for the refrigerant in the outdoor heat exchanger 205 to flow into the refrigerant recovery tank 207. The refrigerant in the refrigerant recovery tank 207 enters the gas-liquid separator 203, leaving space in the refrigerant recovery tank 207 to receive refrigerant from the outdoor heat exchanger 205. After the refrigerant in the outdoor heat exchanger 205 flows into the refrigerant recovery tank 207, some space is freed up in the outdoor heat exchanger 205. In this way, after the compressor 204 is started, the gaseous refrigerant discharged from the outlet of the compressor 204 can enter the outdoor heat exchanger 205, so that the outdoor heat exchanger 205 can convert most of it into room temperature high-pressure liquid refrigerant. In other words, the outdoor heat exchanger 205 can function normally at this time, and the air conditioner will not fail to operate normally due to the outdoor heat exchanger 205 failing to function properly. Conversely, if the refrigerant does not flow out of the outdoor heat exchanger 205, then the outdoor heat exchanger 205 will be filled with the recovered refrigerant. The outdoor heat exchanger 205 will not have enough space to allow more refrigerant to enter. Therefore, when the compressor 204 starts, the gaseous refrigerant discharged from the outlet of the compressor 204 cannot enter the outdoor heat exchanger 205. Naturally, the outdoor heat exchanger 205 will not be able to function with the gaseous refrigerant (the outdoor heat exchanger 205 can only function with the refrigerant if it enters the outdoor heat exchanger 205), thus causing the air conditioner to malfunction.

[0045] It should be noted that the control method of the present invention includes the steps of "selectively keeping the first on / off valve 209 intermittently open" and "keeping the outdoor expansion valve 206 in a state that allows refrigerant flow." Although the above description uses the former followed by the latter as an example, the order of execution can be adjusted. For example, the step of "keeping the outdoor expansion valve 206 in a state that allows refrigerant flow" can be executed first, followed by the step of "selectively keeping the first on / off valve 209 intermittently open." Alternatively, both steps can be executed simultaneously. Furthermore, after repairing the refrigerant leak, when it is necessary to start the compressor, the compressor can be started during or after the execution of the control method of the present invention. Of course, the compressor can also be started first, followed by the execution of the control method of the present invention.

[0046] Preferably, in step S2, the outdoor expansion valve 206 is set to its maximum opening, allowing the refrigerant to flow out of the outdoor heat exchanger 205 more quickly, thus enabling the compressor 204 to start earlier and provide air conditioning to the user. Of course, in step S2, the opening of the outdoor expansion valve 206 can also be at its minimum or a medium opening, and it does not have to be set to its maximum opening.

[0047] Preferably, the step of "intermittently keeping the first on / off valve 209 in the open state by alternating opening and closing" specifically includes:

[0048] Open the first on / off valve 209;

[0049] Obtain the current liquid level of the gas-liquid separator 203;

[0050] Determine whether the current liquid level has reached the first preset liquid level;

[0051] The first on / off valve 209 is closed whenever the current liquid level reaches the first preset liquid level, and the first on / off valve 209 is reopened whenever the current liquid level is lower than the first preset liquid level.

[0052] The first preset liquid level does not exceed the highest allowable liquid level within the gas-liquid separator 203.

[0053] Whenever the liquid level reaches the first preset liquid level, the first on / off valve 209 is closed, which can stop the injection of refrigerant into the gas-liquid separator 203 in time, and prevent the refrigerant in the gas-liquid separator 203 from exceeding its maximum allowable liquid level, thereby causing liquid refrigerant to enter the compressor 204 and cause liquid slugging. The refrigerant entering the gas-liquid separator 203 from the refrigerant recovery tank 207 is in a gas-liquid mixed state. Therefore, the detected liquid level in the gas-liquid separator 203 will be relatively high. As time goes by, the gaseous refrigerant in the gas-liquid mixed state in the gas-liquid separator 203 rises due to its lower density, while the liquid refrigerant settles due to its higher density. This results in a state where the refrigerant is separated into gas and liquid, with the gaseous refrigerant on top and the liquid refrigerant at the bottom. At this time, the detected liquid level will be lower than the first preset liquid level. At this point, reopening the first on / off valve 209 can continue to inject the refrigerant from the refrigerant recovery tank 207 into the gas-liquid separator 203, making fuller use of the space in the gas-liquid separator 203, thereby discharging as much refrigerant as possible from the refrigerant recovery tank 207, and thus allowing the refrigerant in the outdoor heat exchanger 205 to also be discharged as much as possible.

[0054] In some alternative implementations, the number of times the first on / off valve is opened and closed, as well as the duration of each opening and closing, can be preset to keep the first on / off valve intermittently open. Of course, the specific number of times and duration need to be determined through prior testing to ensure that the settings of these times and durations can help the compressor 204 start smoothly.

[0055] More preferably, the control method further includes:

[0056] After each closure of the first on / off valve 209, obtain the duration of the closure of the first on / off valve 209 in this instance;

[0057] Determine if the duration has reached the preset duration;

[0058] If the time reaches the preset time, the current liquid level of the gas-liquid separator 203 is obtained again and it is determined whether the current liquid level has reached the first preset liquid level.

[0059] In the preferred embodiment described above, the preset duration can be flexibly set to a specific value by those skilled in the art. If the current liquid level obtained again does not reach the first preset liquid level, it indicates that the gas-liquid separator 203 can still be injected with refrigerant. Therefore, the first on-off valve 209 can be reopened to continue injecting refrigerant into the gas-liquid separator 203. If the first preset liquid level is reached, it indicates that the gas-liquid separator 203 has contained enough refrigerant. Therefore, the first on-off valve 209 is not opened but remains closed. More preferably, if it is determined that the current liquid level has reached the first preset liquid level after the step of obtaining the current liquid level again, in addition to keeping the first on-off valve 209 closed, the compressor 204 can also be started to adjust the air quality for the user in a timely manner.

[0060] The current liquid level of the gas-liquid separator 203 is acquired again only after the first on-off valve 209 has been closed for a certain period of time. The system then determines whether the current liquid level has reached the first preset level, and decides whether the first on-off valve 209 needs to be reopened based on the current liquid level. Each time the first on-off valve 209 is closed, it takes some time for the gaseous and liquid refrigerant in the gas-liquid separator 203 to separate. In other words, the liquid level may drop after a certain period. Therefore, as long as the preset time is set reasonably, acquiring the current liquid level of the gas-liquid separator 203 only after the first on-off valve 209 has been closed for the preset time will not affect the overall efficiency of refrigerant injection into the gas-liquid separator 203. At the same time, this setting reduces the number of times the current liquid level of the gas-liquid separator 203 is acquired, thereby reducing the workload of the controller and enabling it to handle more other control operations.

[0061] In some alternative implementations, after each closure of the first on / off valve, the system may receive a user's instruction to the air conditioner requesting the current liquid level of the gas-liquid separator 203 and determining whether it has reached the preset liquid level. If such an instruction is received, the system may then obtain the current liquid level of the gas-liquid separator 203 and determine whether it has reached the preset liquid level.

[0062] Preferably, when the first on / off valve 209 is in the open state, the outdoor expansion valve 206 is in the state of minimum opening.

[0063] In the preferred embodiment described above, as mentioned earlier, when the first on / off valve 209 is in the open state, the refrigerant in the refrigerant recovery tank 207 can automatically flow into the gas-liquid separator 203. If the outdoor expansion valve 206 is open at this time, a large amount of refrigerant will rush from the outdoor heat exchanger 205 into the refrigerant recovery tank 207, resulting in a large refrigerant flow rate from the refrigerant recovery tank 207 into the gas-liquid separator 203. This causes the refrigerant in the gas-liquid separator 203 to be violently disturbed, and the liquid level obtained in the gas-liquid separator 203 will be relatively high. In fact, the obtained liquid level is falsely high. If the refrigerant in the gas-liquid separator 203 is not violently disturbed, the obtained liquid level will not be so high. In the preferred embodiment described above, when the first shut-off valve 209 is in the open state, the outdoor expansion valve 206 is in the state of minimum opening. This can prevent a large amount of refrigerant from rushing from the outdoor heat exchanger 205 into the refrigerant recovery tank 207, thereby making the refrigerant flow rate from the refrigerant recovery tank 207 into the gas-liquid separator 203 relatively small. In this way, the disturbance to the refrigerant in the gas-liquid separator 203 is small, and the liquid level of the gas-liquid separator 203 will not be falsely high. In addition, when the first shut-off valve 209 is closed whenever the current liquid level reaches the first preset liquid level, the liquid level of the gas-liquid separator 203 will not be falsely high. This avoids closing the first shut-off valve 209 when it is not necessary to close it, which would affect the overall efficiency of refrigerant entering the gas-liquid separator 203.

[0064] Preferably, the control method further includes:

[0065] During the process of compressor 204 being in operation to recover refrigerant to refrigerant recovery tank 207 and outdoor heat exchanger 205, the third shut-off valve 211 is closed.

[0066] If refrigerant needs to be recovered into the refrigerant recovery tank 207 and the outdoor heat exchanger 205, the air conditioner 2 needs to be in cooling mode. For the air conditioner 2 in this preferred embodiment, in addition to the compressor 204 needing to be operational, the four-way reversing valve 208 also needs to be in a state that enables the air conditioner to be in cooling mode. When the air conditioner 2 is in cooling mode, the flow direction of the refrigerant in the main refrigerant circulation loop is as follows: Figure 2 As shown, and in Figure 2The dashed lines inside the four-way reversing valve 208 indicate a closed circuit, and the solid lines indicate a closed circuit. The specific flow direction is as follows: the refrigerant flows sequentially through the indoor expansion valve 201, indoor heat exchanger 202, four-way reversing valve 208, gas-liquid separator 203, compressor 204, four-way reversing valve 208, outdoor heat exchanger 205, outdoor expansion valve 206, refrigerant recovery tank 207, and third shut-off valve 211. After flowing through the third shut-off valve 211, the refrigerant flows back to the indoor expansion valve 201. In the control method of this preferred embodiment, during the process of the compressor 204 being in operation to recover refrigerant into the refrigerant recovery tank 207 and the outdoor heat exchanger 205, the third shut-off valve 211 is closed, so that after the refrigerant enters the refrigerant recovery tank 207 and the outdoor heat exchanger 205, it cannot flow through the third shut-off valve 211 and thus cannot return to the indoor side of the air conditioner 2, so that the refrigerant is stored in the refrigerant recovery tank 207 and the outdoor heat exchanger 205, thereby realizing refrigerant recovery.

[0067] In some alternative implementations, refrigerant recovery can be achieved without compressor 204. For example, an opening can be provided on the refrigerant pipeline on the outdoor side of the air conditioner. This opening can be normally sealed with a plug or the like. When refrigerant leakage occurs on the indoor side of the air conditioner 2, the plug is removed, and a suction pump is connected to the opening. The refrigerant is then extracted by the suction pump and compressed into liquid and injected into the refrigerant recovery tank 207 and the outdoor heat exchanger 205. Of course, during the refrigerant injection process, the third shut-off valve 211 must be closed to prevent the refrigerant from flowing back to the indoor side of the air conditioner 2.

[0068] Preferably, the control method further includes:

[0069] During the process of compressor 204 being in operation to recover refrigerant to refrigerant recovery tank 207 and outdoor heat exchanger 205, the second on / off valve 210 is opened so that gaseous refrigerant flows from refrigerant recovery tank 207 into the inlet of compressor 204 until the liquid level in refrigerant recovery tank 207 reaches the second preset liquid level.

[0070] The second preset liquid level shall not exceed the highest allowable liquid level in the refrigerant recovery tank 207.

[0071] In the preferred embodiment described above, the air conditioner 2 is in cooling mode during the refrigerant recovery process, and in cooling mode, the outdoor heat exchanger 205 is used as a condenser. Although the condenser has the function of liquefying the refrigerant, in reality, most of the refrigerant is liquefied, and a small amount of refrigerant remains in a gaseous state. Therefore, the refrigerant flowing out of the outdoor heat exchanger 205 is in a gas-liquid mixed state, which makes the refrigerant in the refrigerant recovery tank 207 also in a gas-liquid mixed state. In the gas-liquid mixed refrigerant, the gaseous refrigerant rises due to its lower density, while the liquid refrigerant settles due to its higher density. Therefore, as long as the second branch is connected to the upper part of the refrigerant recovery tank 207, it can be connected to the gaseous refrigerant in the refrigerant recovery tank 207. In this way, when the second shut-off valve 210 is in the open state, the gaseous refrigerant in the refrigerant recovery tank 207 will flow from the refrigerant recovery tank 207 into the inlet of the compressor 204. On the one hand, the gaseous refrigerant is discharged from the refrigerant recovery tank 207, leaving more space for the storage of liquid refrigerant in the refrigerant recovery tank 207, and also reducing the pressure in the refrigerant recovery tank 207, so that the refrigerant recovery tank 207 can store more liquid refrigerant. On the other hand, after the gaseous refrigerant flowing out of the refrigerant recovery tank 207 flows into the inlet of the compressor 204, it will re-enter the outdoor heat exchanger 205 to be liquefied, and then enter the refrigerant recovery tank 207. This is equivalent to turning the gaseous refrigerant in the refrigerant recovery tank 207 into liquid by circulating it again in the refrigerant main circuit, and then storing it in the refrigerant recovery tank 207 again, saving storage space in the refrigerant recovery tank 207, so that the refrigerant recovery tank 207 can store more refrigerant.

[0072] In some alternative implementations, the second on / off valve 210 may be closed while the compressor 204 is in operation to recover refrigerant to the refrigerant recovery tank 207 and the outdoor heat exchanger 205.

[0073] The technical solution of the present invention will now be illustrated with a specific embodiment, still using air conditioner 2. Figure 2 Taking the structure shown as an example, the control method of air conditioner 2 is as follows: Figure 4 As shown, the control method includes:

[0074] S101. In the event of refrigerant leakage on the indoor side of air conditioner 2, the air conditioner 2 shall be put into cooling mode, the second on / off valve 210 shall be opened and the third on / off valve 211 shall be closed.

[0075] S102. After all the refrigerant has entered the refrigerant receiver tank and outdoor heat exchanger 205, shut down the compressor 204.

[0076] S103, to bring the outdoor expansion valve 206 to its minimum opening degree;

[0077] S104. Open the first shut-off valve 209;

[0078] S105. Obtain the current liquid level of the gas-liquid separator 203;

[0079] S106. Determine whether the current liquid level has reached the first preset liquid level. If it has, proceed to step S107. If it has not, proceed to step S105.

[0080] S107. Close the first on / off valve 209;

[0081] S108. Obtain the duration of the closure of the first on / off valve 209 this time;

[0082] S109. Determine whether the time has reached the preset time. If it has, proceed to step S110. If it has not, proceed to step S108.

[0083] S110. Obtain the current liquid level of the gas-liquid separator 203;

[0084] S111. Determine whether the current liquid level has reached the first preset liquid level. If it has, proceed to step S112. If it has not, proceed to step S110.

[0085] S112. Keep the first on / off valve 209 closed, open the third on / off valve 211 and start the compressor 204.

[0086] Although the above is a combination Figure 2 The control method of the present invention is illustrated by the air conditioner shown in the figure. The air conditioner includes a second branch, a second on / off valve, a liquid level detection device, etc. However, it should be noted that those skilled in the art can select or omit the components in the air conditioner according to the specific circumstances of the steps included in the control method. For example, when the air conditioner control method does not involve steps related to the second branch, the second on / off valve, and the liquid level detection device, those skilled in the art can omit these components.

[0087] On the other hand, this application also proposes an air conditioner whose controller is configured to perform any of the control methods of an air conditioner as described above.

[0088] Of course, the alternative implementation methods described above, as well as the alternative implementation methods and preferred implementation methods, can be used in combination to create new implementation methods that are suitable for more specific application scenarios.

[0089] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims of this invention, any of the claimed embodiments can be used in any combination.

[0090] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method for an air conditioner, characterized in that, The air conditioner includes an indoor heat exchanger, a gas-liquid separator, a compressor, an outdoor heat exchanger, and a refrigerant container, all connected by pipes. The air conditioner also includes a control valve, which is disposed between the outdoor heat exchanger and the refrigerant container and located at the end of the outdoor heat exchanger away from the compressor. The control valve is used to control the flow rate of the refrigerant flowing through it. When the control valve is in a state that allows the refrigerant to flow through, the refrigerant in the outdoor heat exchanger can flow into the refrigerant container. The air conditioner also includes a first branch and a first on / off valve disposed on the first branch. The first end of the first branch is connected to the refrigerant container, and the second end of the first branch is connected to the inlet of the gas-liquid separator. When the first on / off valve is in the open state, the refrigerant in the refrigerant container can flow into the gas-liquid separator. The control method includes: When the refrigerant has been recovered into the outdoor heat exchanger and the refrigerant container, the first on / off valve is selectively and intermittently opened so that the refrigerant in the refrigerant container flows into the gas-liquid separator. The control valve is positioned to allow the refrigerant to flow through it; The air conditioner also includes a second branch and a second on / off valve disposed on the second branch. The second branch connects the inlet end of the compressor and the outlet of the refrigerant container that can discharge gaseous refrigerant. The control method further includes: During the process of the compressor being in operation to recover refrigerant into the refrigerant container and the outdoor heat exchanger, the second on / off valve is opened so that gaseous refrigerant flows from the refrigerant container into the inlet of the compressor until the liquid level in the refrigerant container reaches the second preset liquid level. Wherein, the second preset liquid level does not exceed the highest allowable liquid level in the refrigerant container.

2. The control method for an air conditioner according to claim 1, characterized in that, The step of "selectively keeping the first on / off valve intermittently open" specifically includes: The first on / off valve is intermittently kept in the open state by alternating opening and closing.

3. The control method for an air conditioner according to claim 2, characterized in that, The step of "intermittently keeping the first on-off valve in the open state by alternating opening and closing" specifically includes: Open the first on / off valve; Obtain the current liquid level of the gas-liquid separator; Determine whether the current liquid level has reached the first preset liquid level; The first on / off valve is closed whenever the current liquid level reaches the first preset liquid level, and the first on / off valve is reopened when the current liquid level is lower than the first preset liquid level. Wherein, the first preset liquid level does not exceed the highest liquid level allowed in the gas-liquid separator.

4. The control method for an air conditioner according to claim 3, characterized in that, The control method further includes: After each time the first on / off valve is closed, the duration of the closure of the first on / off valve is obtained; Determine whether the duration has reached the preset duration; If the duration reaches the preset duration, the current liquid level of the gas-liquid separator is obtained again, and it is determined whether the current liquid level has reached the first preset liquid level.

5. The control method for an air conditioner according to any one of claims 1 to 4, characterized in that, The control valve is the outdoor electronic expansion valve of the air conditioner; The step of "putting the control valve in a state that allows the refrigerant to flow" specifically includes: This puts the control valve in its maximum opening state.

6. The control method for an air conditioner according to claim 5, characterized in that, The control method further includes: When the first on / off valve is in the open state, the control valve is made to be in the state of minimum opening.

7. The control method for an air conditioner according to claim 1, characterized in that, The air conditioner also includes a third on / off valve disposed between the refrigerant container and the indoor heat exchanger. The control method further includes: During the operation of the compressor to recover refrigerant into the refrigerant container and the outdoor heat exchanger, the third on / off valve is kept closed.

8. The control method for an air conditioner according to any one of claims 1 to 4, characterized in that, The refrigerant container is the refrigerant recovery tank of the air conditioner.

9. An air conditioner, comprising a controller, characterized in that, The controller is configured to perform the control method of the air conditioner according to any one of claims 1 to 8.

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