Refrigerant recovery system, air conditioner, and control method thereof

Abstract

The application provides a refrigerant recovery system, an air conditioner and a control method thereof, wherein the refrigerant recovery system comprises a four-way valve; the four-way valve comprises a first outlet, a second outlet, a third outlet and a fourth outlet; the first outlet is communicated with an outlet of a compressor through a fourth branch; the second outlet is communicated with an inlet of a heat exchanger through a third branch; the third outlet is communicated with an inlet of a gas-liquid separator through a sixth branch; an outlet of the gas-liquid separator is communicated with an inlet of the compressor through a seventh branch; an outlet of the heat exchanger and the fourth outlet are communicated with an indoor unit; the refrigerant recovery system further comprises a second branch; one end of the second branch is communicated with the sixth branch; the other end of the second branch is communicated with the fourth branch; a second valve body is arranged on the second branch; and a first valve body is arranged on the third branch. According to the application, the technical problem that all components of the outdoor unit of the air conditioner contain refrigerant after refrigerant recovery of the air conditioner in the prior art can be solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of air conditioners, and particularly relates to a refrigerant recovery system, an air conditioner and a control method thereof. BACKGROUND

[0002] In actual use, air conditioning systems often have various problems that require refrigerant recovery, such as replacement of indoor and outdoor units or repair and replacement of damaged valve bodies and other system components. At this time, the usual practice is to manually control the stop valves on the gas pipe and liquid pipe of the outdoor unit to achieve refrigerant recovery. The operation method is to switch the unit to refrigeration mode and run, first close the liquid pipe stop valve, and immediately close the gas pipe stop valve after the unit protection stops. Some technologies support automatic recovery by adding electric ball valves and other valves at the outdoor unit gas pipe and liquid pipe stop valves. The operation is similar to manual operation, first close the valve on the liquid pipe, and then close the gas pipe stop valve after protection or after running for a period of time. However, both of these recovery methods have obvious drawbacks. The refrigerant is recovered to the outdoor unit part, but the refrigerant is distributed in the outdoor heat exchanger, vapor-liquid separator, liquid accumulator (if configured) and outdoor unit pipeline. Such recovery effect can only meet the maintenance and replacement of non-outdoor unit parts. When the outdoor unit valve body and compressor are replaced, the refrigerant inside cannot support hot work and welding.

[0003] Therefore, there is an urgent need for a new technology that can recover refrigerant to the smallest location range during refrigerant recovery. The vapor-liquid separator has a large volume and is the main storage site. If most of the refrigerant is recovered to the vapor-liquid separator, the operator will not face the problem of operating with refrigerant when most of the outdoor unit components are replaced.

[0004] Because the refrigerant recovered by the air conditioner in the prior art is distributed in most of the pipelines inside the outdoor unit, the refrigerant remains in the main components of the outdoor unit after the recovery is completed, resulting in technical problems such as inconvenience in maintenance of the outdoor unit. Therefore, the present application provides a refrigerant recovery system, an air conditioner and a control method thereof. SUMMARY

[0005] Therefore, the present application provides a refrigerant recovery system, an air conditioner and a control method thereof, which can solve the technical problem of refrigerant remaining in all components of the outdoor unit of the air conditioner after refrigerant recovery in the prior art.

[0006] To solve the above problems, the present application provides a refrigerant recovery system, comprising: an indoor unit and an outdoor unit,

[0007] The outdoor unit comprises a vapor-liquid separator, a compressor, a four-way valve and a heat exchanger connected in sequence.

[0008] The four-way valve comprises a first outlet, a second outlet, a third outlet and a fourth outlet, the first outlet is communicated with the outlet of the compressor through a fourth branch, the second outlet is communicated with the inlet of the heat exchanger through a third branch, the third outlet is communicated with the inlet of the gas-liquid separator through a sixth branch, the outlet of the gas-liquid separator is communicated with the inlet of the compressor through a seventh branch, the outlet of the heat exchanger, the fourth outlet and the indoor unit are communicated.

[0009] The refrigerant recovery system further comprises a second branch, one end of the second branch is communicated with the sixth branch, the other end of the second branch is communicated with the fourth branch, a second valve body is arranged on the second branch, and a first valve body is arranged on the third branch.

[0010] In some embodiments, a first branch is communicated with the third branch, one end of the first branch is communicated with the third branch, the other end of the first branch is communicated with the sixth branch, one end of the first branch is located between the first valve body and the heat exchanger, the other end of the first branch is located between the third outlet and the second branch, and a third valve body is arranged on the first branch.

[0011] In some embodiments, the refrigerant recovery system further comprises an oil-gas separator, the oil-gas separator has a first inlet, a second inlet and a fifth outlet, the first inlet is communicated with the outlet of the compressor through a fifth branch, the second inlet is communicated with the seventh branch through the fourth branch, the fifth outlet is communicated with the fourth branch, a sixth valve body is arranged on the fourth branch, and the sixth valve body is located between the fourth branch and the gas-liquid separator.

[0012] In some embodiments, a fourth valve body is arranged on the sixth branch, and the fourth valve body is located between the second branch and the gas-liquid separator.

[0013] In some embodiments, the outlet of the heat exchanger is communicated with the indoor unit through an eighth branch, the fourth outlet is communicated with the indoor unit through a ninth branch, and a fifth valve body is arranged on the eighth branch and the ninth branch.

[0014] The application further provides an air conditioner comprising the above refrigerant recovery system.

[0015] The application further provides a control method of the above air conditioner, which comprises the following steps:

[0016] When the air conditioner needs to start a refrigerant recovery mode;

[0017] A judging step of judging whether the air conditioner is in a refrigeration mode;

[0018] The control step: when the air conditioner is in the refrigeration mode, control the air conditioner to start the refrigerant recovery mode; when the air conditioner is not in the refrigeration mode, control the air conditioner to switch to the refrigeration mode, and then control the air conditioner to start the refrigerant recovery mode.

[0019] In some embodiments, the control of the air conditioner to start the refrigerant recovery mode further comprises the following steps:

[0020] The judgment step: judging whether the air conditioner unit has a sensor fault;

[0021] The control step: when the air conditioner unit does not have a sensor fault, control the air conditioner to start the normal refrigerant recovery mode; when the air conditioner unit has a sensor fault, control the air conditioner to start the sensor fault refrigerant recovery mode.

[0022] In some embodiments, when the third branch is connected with the first branch and the third valve is arranged on the first branch; the control of the air conditioner to start the normal refrigerant recovery mode comprises the following steps: control the compressor to run at the maximum frequency, control the second valve to open, control the third valve to open, and control the first valve to close.

[0023] In some embodiments, the control of the compressor to run at the maximum frequency is implemented according to the following steps: during the frequency increase or running of the compressor, if the high pressure protection value Pb-the air conditioner unit high pressure value Pd≤3℃, the compressor is periodically reduced in frequency until the high pressure protection value Pb-the air conditioner unit high pressure value Pd>4℃; if the compressor has been reduced to the minimum frequency and maintained for a first preset time, or the air conditioner has an air conditioner unit protection, a stop refrigerant recovery instruction is issued.

[0024] In some embodiments, when the third branch is connected with the first branch and the third valve is arranged on the first branch; the control of the air conditioner to start the sensor fault refrigerant recovery mode comprises the following steps: control the air conditioner to shield the sensor fault, forcibly run the refrigerant recovery mode, control the compressor to run at the minimum frequency, control the second valve to open, control the third valve to open, and control the first valve to close.

[0025] In some embodiments, the control of the compressor to run at the minimum frequency is implemented according to the following steps: after the compressor is started, it is first increased to medium frequency running, and then runs at the minimum frequency; if the compressor runs at the minimum frequency and maintains for a second preset time, or the air conditioner has an air conditioner unit protection, a stop refrigerant recovery instruction is issued.

[0026] The refrigerant recovery system, the air conditioner and the control method thereof provided by the application have the following beneficial effects:

[0027] By setting the second valve body on the second branch, and the first valve body on the third branch, when the air conditioner unit needs to carry out refrigerant recovery, the first valve body is closed, and the second valve body is opened, so that the refrigerant discharged by the compressor is recovered into the gas-liquid separator, and under the action of the compressor, the refrigerant in each part of the air conditioner flows into the gas-liquid separator, and the other parts of the outdoor unit no longer face the problem of being unable to be replaced and maintained due to the presence of refrigerant, most of the refrigerant in the air conditioner is recovered, the discharge of refrigerant is greatly reduced, and the recovered refrigerant can be reused, which is environmentally friendly and energy-saving, and reduces maintenance costs. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. The drawings in the following description are only exemplary, and those skilled in the art can also obtain other implementation drawings according to the provided drawings without creative labor.

[0029] Figure 1 is a structural schematic diagram of the refrigerant recovery system of the present application;

[0030] Figure 2 is a refrigerant flow diagram of the refrigerant recovery system of the present application in the refrigeration mode;

[0031] Figure 3 is a refrigerant flow diagram of the refrigerant recovery system of the present application in the recovery mode;

[0032] Figure 4 is a flow chart of the control method of the air conditioner of another embodiment of the present application;

[0033] Figure 5 is a flow chart of the control method of the air conditioner of another embodiment of the present application in the case of no sensor fault;

[0034] Figure 6 is a flow chart of the control method of the air conditioner of another embodiment of the present application in the case of sensor fault.

[0035] The reference signs are:

[0036] 1, compressor; 2, heat exchanger; 3, gas-liquid separator; 4, oil-gas separator; 5, four-way valve; 6, first valve body; 7, first branch; 8, third valve body; 9, third branch; 10, fourth branch; 11, fourth branch; 12, fifth branch; 13, throttling element; 14, second valve body; 15, second branch; 16, sixth branch; 17, fourth valve body; 18, seventh branch; 19, eighth branch; 20, ninth branch; 21, fifth valve body; 22, sixth valve body. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative work belong to the scope of protection of the present application.

[0038] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0039] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper" and the like can be used herein to describe the spatial position relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawings is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0040] In addition, it should be noted that the use of the terms "first", "second" and the like are used to distinguish between components only for the convenience of the corresponding components, and the above terms have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present application.

[0041] In combination with reference to Figures 1-6 As shown, according to the embodiment of the present application, a refrigerant recovery system is provided, comprising: an indoor unit and an outdoor unit, the outdoor unit comprising a gas-liquid separator 3, a compressor 1, a four-way valve 5, a heat exchanger 2 connected in sequence; the four-way valve 5 comprises a first outlet, a second outlet, a third outlet and a fourth outlet, the first outlet is communicated with the outlet of the compressor 1 through a fourth branch 10, the second outlet is communicated with the inlet of the heat exchanger 2 through a third branch 9, the third outlet is communicated with the inlet of the gas-liquid separator 3 through a sixth branch 16, the outlet of the gas-liquid separator 3 is communicated with the inlet of the compressor 1 through a seventh branch 18, the outlet of the heat exchanger 2, the fourth outlet and the indoor unit are communicated;

[0042] The refrigerant recovery system further comprises a second branch 15, one end of the second branch 15 is communicated with the sixth branch 16, the other end of the second branch 15 is communicated with the fourth branch 10, a second valve body 14 is arranged on the second branch 15, and a first valve body 6 is arranged on the third branch 9. In this technical solution, the second valve body 14 is arranged on the second branch 15, and the first valve body 6 is arranged on the third branch 9. When the air conditioner unit needs to recover refrigerant, the first valve body 6 is closed and the second valve body 14 is opened, so that the refrigerant discharged by the compressor 1 is recovered into the gas-liquid separator 3, and under the action of the compressor 1, all the refrigerant in the air conditioner is flowed into the gas-liquid separator 3, and the other parts of the outdoor unit no longer face the problem of being unable to be replaced and maintained due to the accumulation of refrigerant. The recovery of most of the refrigerant in the air conditioner greatly reduces the discharge of refrigerant, and the recovered refrigerant can be used again, which is environmentally friendly and energy-saving, and reduces the maintenance cost.

[0043] In some embodiments, the third branch 9 is communicated with a first branch 7, one end of the first branch 7 is communicated with the third branch 9, the other end of the first branch 7 is communicated with the sixth branch 16, one end of the first branch 7 is located between the first valve body 6 and the heat exchanger 2, and the other end of the first branch 7 is located between the third outlet and the second branch 15, and a third valve body 8 is arranged on the first branch 7. In this technical solution, through the third valve body 8, if the air conditioner is in heating mode before recovery, the third valve body 8 is opened to quickly and effectively recover a large amount of low-temperature refrigerant stored in the outdoor heat exchanger 2 to the gas-liquid separator 3, and if the air conditioner is in cooling mode before recovery, the third valve body 8 does not need to be opened.

[0044] In some embodiments, the refrigerant recovery system further comprises an oil-gas separator 4, the oil-gas separator 4 has a first inlet, a second inlet and a fifth outlet, the first inlet is communicated with the outlet of the compressor 1 through a fifth branch 12, the second inlet is communicated with the seventh branch 18 through the fourth branch 11, the fifth outlet is communicated with the fourth branch 10, the fourth branch 11 is provided with a sixth valve body 22, the sixth valve body 22 is located between the fourth branch 11 and the gas-liquid separator 3. In this technical scheme, through the sixth valve body 22, it is convenient to control that all the refrigerators are recovered to the gas-liquid separator 3, and the refrigerant storage in the compressor is effectively reduced. Compared with the traditional air conditioning system, the refrigerant recovery system of the application increases the sixth valve body 22 and the third valve body 8, and can realize high-precision automatic refrigerant recovery.

[0045] In some embodiments, the sixth branch 16 is provided with a fourth valve body 17, and the fourth valve body 17 is located between the second branch 15 and the gas-liquid separator 3. In this technical scheme, through the fourth valve body 17, the gaseous refrigerant in the gas-liquid separator 3 is prevented from flowing back to the unit after the recovery is completed, and the refrigerant recovery efficiency is improved.

[0046] In some embodiments, the outlet of the heat exchanger 2 is communicated with the indoor unit through an eighth branch 19, the fourth outlet is communicated with the indoor unit through a ninth branch 20, and the eighth branch 19 and the ninth branch 20 are both provided with a fifth valve body 21. In this technical scheme, further, the sixth branch 16 is provided with a low-pressure sensor and a steam inlet pipe temperature sensor, the low-pressure sensor and the steam inlet pipe temperature sensor are both located between the second branch 15 and the first branch 7, the seventh branch 18 is provided with a steam outlet pipe temperature sensor, the fifth branch 12 is provided with a high-pressure switch and an exhaust temperature sensor, the fourth branch 10 is provided with a high-pressure temperature sensor, the eighth branch 19 is provided with a defrosting temperature sensor and a heating EEV, the defrosting temperature sensor and the heating EEV are sequentially arranged on the eighth branch 19 along the flow direction of the indoor medium of the eighth branch 19, the first branch 7 and the second branch 15 are both provided with a throttling part 13, the throttling part 13 on the first branch 7 is located between the third valve body 8 and the heat exchanger 2, and the throttling part 13 on the second branch 15 is located between the second valve body 14 and the first outlet. Since the compressor 1 discharges high-temperature and high-pressure refrigerant, through the throttling part 13, the refrigerant can be effectively throttled and decompressed during recovery, and the recovery efficiency is improved.

[0047] The refrigerant recovery system of the present application solves the problems of the prior art, such as the need for manual operation, the distribution of the recovered refrigerant in most of the pipelines inside the outdoor unit, the presence of refrigerant in the main components of the outdoor unit after the recovery is completed, the inaccuracy of automatic refrigerant recovery control, the inability to maximize the recovery of refrigerant, and the inability to perform recovery after the failure of the high-pressure sensor and the low-pressure sensor. The refrigerant recovery system of the present application can maximize the recovery of refrigerant, and does not have the problems of low recovery efficiency and low recovery amount as in the prior art. Recovery can still be performed after a failure, which improves the applicable scenarios and brings greater convenience.

[0048] The refrigerant flow direction in the refrigerant recovery system of the present application is as follows:

[0049] In the normal refrigeration mode: the compressor works, the refrigerant is discharged from the discharge port of the compressor 1 and flows into the oil-gas separator 4, then flows into the outdoor heat exchanger 2 through the four-way valve 5, at this time the first valve body 6 is in an open state, the condensed refrigerant flows into the indoor liquid pipe and the indoor heat exchanger through the heating EXV-outdoor liquid pipe, then flows out through the indoor gas pipe, and then flows into the outdoor gas pipe, the refrigerant flows into the four-way valve 5 through the outdoor gas pipe and then flows into the gas-liquid separator 3, flows into the suction pipe of the compressor 1 through the outlet pipe of the gas-liquid separator 3, and then the compressor is compressed again, and the cycle is repeated.

[0050] In the refrigerant recovery mode: after the recovery instruction is issued, the air conditioner first operates in the refrigeration mode, the compressed refrigerant of the compressor 1 flows out through the oil-gas separator 4, the first valve body 6 is closed and the second valve body 14 is opened, at this time, part of the refrigerant flows into the gas-liquid separator 3 through the immediately opened second valve body 14, the flow of this refrigerant is very small, which is only a simple bypass, the first valve body 6 is closed to keep the refrigerant from flowing out, and most of the refrigerant is left between the compressor 1 and the four-way valve 5, and then flows back to the compressor 1 through the gas-liquid separator 3. Most of the refrigerant is blocked between the compressor 1 and the high-pressure recovery valve 6, and due to the continuous operation of the compressor, the "suction" is provided, so that the refrigerant in the pipeline continues to flow into the gas-liquid separator 3 through the pipeline.

[0051] The present application also provides an air conditioner comprising the above-mentioned refrigerant recovery system.

[0052] The present application also provides a control method for the above-mentioned air conditioner, comprising the following steps:

[0053] When the air conditioner needs to start the refrigerant recovery mode;

[0054] The judgment step: judging whether the air conditioner is in the refrigeration mode;

[0055] The control step: when the air conditioner is in the refrigeration mode, control the air conditioner to start the refrigerant recovery mode; when the air conditioner is not in the refrigeration mode, control the air conditioner to switch to the refrigeration mode, and then control the air conditioner to start the refrigerant recovery mode.

[0056] In some embodiments, the control of the air conditioner to start the refrigerant recovery mode further comprises the following steps:

[0057] The judgment step: judging whether the air conditioner unit has sensor failure;

[0058] The control step: when the air conditioner unit has no sensor failure, control the air conditioner to start the normal refrigerant recovery mode; when the air conditioner unit has sensor failure, control the air conditioner to start the sensor failure refrigerant recovery mode.

[0059] The air conditioner unit is provided with refrigerant high-precision recovery matching hardware and control. If refrigerant recovery is to be started, there are two ways, one is manual operation start, through the outdoor unit main control board button operation, the related program is built-in in the outdoor unit main control board; one is to receive the signal of the refrigerant leakage detection sensor, and then automatically start the recovery after receiving the signal of the refrigerant leakage detection sensor.

[0060] After receiving the refrigerant recovery instruction, the unit will first self-check. If the unit sensor has no failure and can normally participate in judgment, the normal recovery mode is started first. This mode has fast recovery speed and high recovery precision. If the unit sensor has failure, the recovery method in the failure mode is started, the related failure signals are shielded, and effective recovery is carried out.

[0061] In some embodiments, when the third branch 9 is communicated with the first branch 7, and the third valve body 8 is arranged on the first branch 7; the control of the air conditioner to start the normal refrigerant recovery mode comprises the following steps: control the compressor 1 to run at the maximum frequency, control the second valve body 14 to open, control the third valve body 8 to open, and control the first valve body 6 to close.

[0062] Normal refrigerant recovery control method

[0063] When the refrigerant is recovered, the air conditioner is switched to the refrigeration mode first, and the recovery efficiency is high in the refrigeration mode. The four-way valve 5 is in a power-off state in the refrigeration mode. If the air conditioner is in the heating mode, the four-way valve 5 will automatically reset after the outdoor unit is powered off. A first valve body 6 is added to the connecting pipe between the outdoor heat exchanger 2 and the four-way valve 5. If the refrigerant is recovered in the heating mode, the first valve body 6 cannot be closed, the four-way valve 5 is powered off, and then the compressor 1 starts to increase the frequency and reaches the highest target. The higher the frequency of the compressor, the faster and better the recovery effect. After the frequency is increased, the first valve body 6 is closed to prevent the refrigerant from flowing out. At this time, in order to give a certain pressure relief and improve the recovery effect, the second valve body 14 needs to be opened to allow a part of the refrigerant to flow to the low-pressure side. If the air conditioner is in the heating mode before the refrigerant is recovered, the third valve body 8 also needs to be opened. In order to quickly and effectively recover the large amount of low-temperature refrigerant stored in the outdoor heat exchanger 2 to the gas-liquid separator 3, if the refrigerant is recovered before the refrigeration, the third valve body 8 does not need to be opened.

[0064] When the system refrigerant recovery is almost complete, the air conditioner unit appears exhaust, pressure anomaly protection, or maintains the minimum frequency for a long time, which is about 3 minutes. At this time, the sixth valve body 22 of the gas-liquid separator 3 needs to be closed first, and the sixth valve body 22 is closed about 1 minute earlier than the seventh branch 17. The purpose is to maximize the recovery to the gas-liquid separator 3 and reduce the recovery refrigerant amount ratio from the gas-liquid separator 3 to the compressor 1 side. Then, the seventh branch 17 is closed to end the refrigerant recovery.

[0065] In some embodiments, the control of the compressor 1 operating at the maximum frequency is implemented according to the following steps: during the frequency increase or operation of the compressor 1, if the high-pressure protection value Pb minus the air conditioner unit high-pressure value Pd≤3℃, the compressor 1 periodically reduces the frequency until the high-pressure protection value Pb minus the air conditioner unit high-pressure value Pd>4℃. If the compressor 1 has been reduced to the minimum frequency and maintained for a first predetermined time, or the air conditioner appears air conditioner unit protection, the refrigerant recovery stop command is issued.

[0066] The first preset time is 3 minutes, the air conditioner is controlled to start the normal refrigerant recovery mode, the compressor 1 is controlled to run at the maximum frequency, the compressor 1 is raised in frequency or runs, if the module high pressure value is raised to the vicinity of the protection value, that is, the high pressure protection value Pb-module high pressure value Pd≤3℃, the compressor is reduced in frequency by 3HZ speed every 10 seconds of the normal cycle value, the normal cycle value is 10 seconds, and the high pressure protection value Pb-module high pressure value Pd>4℃. If the compressor 1 has been reduced to the minimum frequency and maintained for 3 minutes or more, or the unit protection occurs, a stop refrigerant recovery instruction is sent out, the related valves are linked, the control of each valve body of the air conditioner is started in the normal refrigerant recovery mode, the second valve body 14 is immediately opened until the recovery is ended and the normal control is restored; before the third valve body 8 receives the recovery instruction, if the air conditioner unit is in the refrigeration mode, the third valve body 8 is kept closed. If the air conditioner unit is in the heating mode before the recovery, the third valve body 8 is immediately opened and maintained until the sixth valve body 22 is closed 1 minute before the third valve body 8 is closed; the first valve body 6 is closed after the compressor 1 is raised to the highest frequency or the first valve body 6 is closed when the high pressure is reduced in frequency during the process that the compressor 1 is raised in frequency; the fourth valve body 17 is closed immediately after receiving the stop recovery instruction, or the compressor 1 is reduced to the minimum frequency and maintained for 3 minutes, or the unit protection is stopped; the sixth valve body 22 is closed immediately 1 minute before receiving the stop recovery instruction, or the compressor 1 is reduced to the minimum frequency and maintained for 2 minutes, or the unit protection is stopped. The sixth valve body 22 is normally open; the four-way valve 5 is kept or switched to the power-off state, that is, switched to the refrigeration mode.

[0067] In some embodiments, when the third branch 9 is communicated with the first branch 7, and the third valve body 8 is arranged on the first branch 7; the control method of the air conditioner starting the sensor fault refrigerant recovery mode comprises the following steps: the air conditioner is controlled to shield the sensor fault, and the refrigerant recovery mode is forced to run, the compressor 1 is controlled to run at the minimum frequency, the second valve body 14 is controlled to be opened, the third valve body 8 is controlled to be opened, and the first valve body 6 is controlled to be closed.

[0068] The control method of the refrigerant recovery mode in the sensor fault mode is,

[0069] When the unit appears pressure sensor abnormal, it is impossible to control the precise recovery by judging the pressure parameter, at this time it is necessary to control by "time", according to the experience to confirm the setting recovery for how long can basically complete the refrigerant recovery. Because the pressure can not participate in the judgment, if the unit is high frequency operation, it may appear damage or failure, so the recovery operation frequency should be limited, it can not be too high to let the unit appear damage risk, it can not be too low to make the recovery effect bad. Specifically, first let the compressor 1 run at medium frequency for a period of time, then the compressor 1 runs at medium frequency in order to balance the recovery effect and the safety of the air conditioner unit, and then runs at low frequency. With the decrease of refrigerant, the frequency needs to be reduced to ensure the safety of operation, and the rest of the valve control refers to the control in the normal operation mode.

[0070] In some embodiments, the compressor 1 is controlled to run at the minimum frequency according to the following steps: after the compressor 1 is started, it is first raised to medium frequency operation, and then runs at the minimum frequency. If the compressor 1 runs at the minimum frequency and maintains for a second predetermined time, or the air conditioner appears air conditioner unit protection, a stop refrigerant recovery instruction is issued.

[0071] The second predetermined time is 15 minutes. When the air conditioner starts the sensor fault refrigerant recovery mode, the fault is shielded and forced to run, the compressor 1 is controlled to run at the minimum frequency. After the compressor 1 is started, it is first raised to medium frequency operation for 3 minutes, and then runs at the minimum frequency. The medium frequency is 50%*maximum frequency. If the compressor 1 runs at the minimum frequency and maintains for more than 15 minutes, or the unit protection appears, a stop refrigerant recovery instruction is issued, and the related valves are linked. When the air conditioner starts the sensor fault refrigerant recovery mode, the second valve 14 is immediately opened until the recovery is completed and the normal control is restored. Before the third valve 8 receives the recovery instruction, if the air conditioner unit runs in refrigeration mode, it remains closed. If it runs in heating mode before recovery, it is immediately opened and maintained until the sixth valve 22 is closed 1 minute before it is closed. The third valve 8 is normally closed when the unit is normally running. The first valve 6 is closed after the compressor 1 is raised to the maximum frequency, or it is closed when the compressor 1 triggers high pressure frequency reduction during the frequency raising process. The first valve 6 is normally open when it is normally running. The fourth valve 17 is closed immediately after receiving the stop recovery instruction, or the compressor 1 is reduced to the minimum frequency and maintains for 3 minutes, or the unit protection stops running. The fourth valve 17 is normally open when it is normally running. The sixth valve 22 is closed immediately 1 minute before receiving the stop recovery instruction, or it is closed immediately when the compressor 1 is reduced to the minimum frequency and maintains for 2 minutes, or the unit protection stops running. The sixth valve 22 is normally open when it is normally running. The four-way valve 5 remains or switches to the power-off state, that is, it switches to the refrigeration mode.

[0072] The control method of the air conditioner can improve the rationality and precision of recovery. Two recovery modes are designed, in addition to the traditional parameter judgment, a refrigerant recovery method under a fault mode is also designed to improve the scene applicability.

[0073] Those skilled in the art can easily understand that the advantageous technical features of each mode described above can be freely combined and superimposed without conflict.

[0074] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above only describes the preferred embodiments of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and variations can also be made, which should be considered as the protection scope of the present application.

Claims

1. A refrigerant recovery system characterized by: The system comprises: an indoor unit and an outdoor unit, the outdoor unit comprises, in sequence, a gas-liquid separator (3), a compressor (1), a four-way valve (5), and a heat exchanger (2); the four-way valve (5) comprises a first outlet, a second outlet, a third outlet, and a fourth outlet, the first outlet is connected to the outlet of the compressor (1) through a fourth branch (10), the second outlet is connected to the inlet of the heat exchanger (2) through a third branch (9), the third outlet is connected to the inlet of the gas-liquid separator (3) through a sixth branch (16), the outlet of the gas-liquid separator (3) is connected to the inlet of the compressor (1) through a seventh branch (18), the outlet of the heat exchanger (2) and the fourth outlet are connected to the indoor unit; the refrigerant recovery system further comprises a second branch (15), one end of the second branch (15) is connected to the sixth branch (16), the other end of the second branch (15) is connected to the fourth branch (10), a second valve body (14) is arranged on the second branch (15), a first valve body (6) is arranged on the third branch (9); the third branch (9) is connected to a first branch (7), one end of the first branch (7) is connected to the third branch (9), the other end of the first branch (7) is connected to the sixth branch (16), one end of the first branch (7) is located between the first valve body (6) and the heat exchanger (2), the other end of the first branch (7) is located between the third outlet and the second branch (15), and a third valve body (8) is arranged on the first branch (7).

2. The refrigerant recovery system of claim 1, wherein: The refrigerant recovery system further comprises an oil-gas separator (4), the oil-gas separator (4) has a first inlet, a second inlet, and a fifth outlet, the first inlet is connected to the outlet of the compressor (1) through a fifth branch (12), the second inlet is connected to the seventh branch (18) through a tenth branch (11), and the fifth outlet is connected to the fourth branch (10), a sixth valve body (22) is arranged on the tenth branch (11), and the sixth valve body (22) is located between the tenth branch (11) and the gas-liquid separator (3).

3. The refrigerant recovery system of claim 1, wherein: A fourth valve body (17) is arranged on the sixth branch (16), and the fourth valve body (17) is located between the second branch (15) and the gas-liquid separator (3).

4. The refrigerant recovery system of claim 1, wherein: The outlet of the heat exchanger (2) is connected to the indoor unit through an eighth branch (19), the fourth outlet is connected to the indoor unit through a ninth branch (20), and a fifth valve body (21) is arranged on the eighth branch (19) and the ninth branch (20).

5. An air conditioner characterized by comprising: The system comprises the refrigerant recovery system according to any one of claims 1 to 4.

6. The control method of the air conditioner according to claim 5, wherein The system comprises the following steps: when the air conditioner needs to start the refrigerant recovery mode; a judgment step of judging whether the air conditioner is in a cooling mode; a control step of controlling the air conditioner to start the refrigerant recovery mode when the air conditioner is in the cooling mode; When the air conditioner is not in the refrigeration mode, the air conditioner is controlled to switch to the refrigeration mode, and then the air conditioner is controlled to start the refrigerant recovery mode.

7. The control method of the air conditioner according to claim 6, wherein The step of controlling the air conditioner to start the refrigerant recovery mode further comprises the following steps: A judgment step of judging whether the air conditioner unit has a sensor fault; A control step of controlling the air conditioner to start a normal refrigerant recovery mode when the air conditioner unit has no sensor fault, and controlling the air conditioner to start a sensor fault refrigerant recovery mode when the air conditioner unit has a sensor fault.

8. The control method of the air conditioner according to claim 7, characterized by, When the third branch (9) is connected with the first branch (7) and the third valve (8) is arranged on the first branch (7), the step of controlling the air conditioner to start the normal refrigerant recovery mode comprises the following steps: controlling the compressor (1) to operate at the maximum frequency, controlling the second valve (14) to open, controlling the third valve (8) to open, and controlling the first valve (6) to close.

9. The control method of the air conditioner according to claim 8, characterized by, The step of controlling the compressor (1) to operate at the maximum frequency is implemented in the following manner: during the frequency increase or operation of the compressor (1), if the high-pressure protection value Pb minus the high-pressure value Pd of the air conditioner unit is less than or equal to 3℃, the compressor (1) is periodically decreased in frequency until the high-pressure protection value Pb minus the high-pressure value Pd of the air conditioner unit is greater than 4℃; if the compressor (1) has been decreased to the minimum frequency for a first preset time, or the air conditioner has an air conditioner unit protection, a stop refrigerant recovery instruction is issued.

10. The control method of the air conditioner according to claim 7, wherein When the third branch (9) is connected with the first branch (7) and the third valve (8) is arranged on the first branch (7), the step of controlling the air conditioner to start the sensor fault refrigerant recovery mode comprises the following steps: the sensor fault is shielded, the refrigerant recovery mode is forced to operate, the compressor (1) operates at the minimum frequency, the second valve (14) is controlled to open, the third valve (8) is controlled to open, and the first valve (6) is controlled to close.

11. The control method of an air conditioner according to claim 10, wherein The step of controlling the compressor (1) to operate at the minimum frequency is implemented in the following manner: after the compressor (1) is started, it is first increased to the medium frequency operation, and then operates at the minimum frequency; if the compressor (1) operates at the minimum frequency for a second preset time, or the air conditioner has an air conditioner unit protection, a stop refrigerant recovery instruction is issued.

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