CN215597815U

CN215597815U - Air conditioner

Info

Publication number: CN215597815U
Application number: CN202121558703.8U
Authority: CN
Inventors: 罗荣邦; 崔俊
Original assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Current assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Priority date: 2021-07-09
Filing date: 2021-07-09
Publication date: 2022-01-21
Anticipated expiration: 2031-07-09

Abstract

The utility model relates to the technical field of air conditioner self-cleaning, in particular to an air conditioner. The oil return method aims at solving the problem that an existing oil return method is poor in oil return effect. Purpose, the air conditioner of this application includes compressor, cross valve, outdoor heat exchanger, throttling arrangement and indoor heat exchanger through refrigerant tube coupling, and the air conditioner still includes the recovery pipeline, and the first end of recovery pipeline sets up on the refrigerant pipe between the export of outdoor heat exchanger and the import of indoor heat exchanger, and the second end of recovery pipeline communicates with the induction port of compressor, is provided with first on-off valve on the recovery pipeline, and first on-off valve is the normally closed valve. Through set up the recovery pipeline in the air conditioner, this application can utilize the recovery pipeline to reduce the flow stroke of high temperature refrigerant, reduce the pressure drop, improve the oil return effect in the oil return process of carrying out indoor heat exchanger and outdoor heat exchanger.

Description

Air conditioner

Technical Field

The utility model relates to the technical field of air conditioner self-cleaning, in particular to an air conditioner.

Background

In the refrigerant circulation process of the air conditioning system, the refrigerating machine oil can participate in circulation along with the refrigerant. Because the hairpin pipes of the indoor heat exchanger and the outdoor heat exchanger are the internal thread copper pipes at present, the flowing of the refrigerating machine oil is influenced, and in addition, the centrifugal force action of the flowing of the refrigerant causes that part of the refrigerating machine oil cannot return to the inside of the compressor in time and stays on the inner wall of the threaded copper pipe, the heat transfer between the refrigerant and the coil pipe is blocked, the heat transfer temperature difference is reduced, and the refrigerating and heating effects of the air conditioner are deteriorated. Meanwhile, the problem that the compressor is not lubricated sufficiently and the like can be caused because part of the refrigerating machine oil does not return to the interior of the compressor in time.

In order to solve the problems, in the prior art, part of manufacturers set an oil return mode in the air conditioner, when the oil return mode operates, the temperature and the flow rate of the refrigerant are increased by increasing the operating frequency of the compressor, reducing the operating speed of the indoor and outdoor fans and the like, and the viscosity of the refrigerating machine oil is reduced by the flowing of the high-temperature refrigerant, and the refrigerating machine oil flows back to the compressor. However, in the circulating flow process of the refrigerant, the refrigerant needs to pass through the coil pipes of the indoor heat exchanger and the outdoor heat exchanger at the same time, the stroke of the refrigerant is long, the pressure drop is large, and the oil return effect is poor.

Accordingly, there is a need in the art for a new air conditioner to solve the above problems.

SUMMERY OF THE UTILITY MODEL

In order to solve at least one problem in the prior art, namely to solve the problem of poor oil return effect existing in the existing oil return method, the air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger which are connected through a refrigerant pipeline, and further comprises a recovery pipeline, wherein a first end of the recovery pipeline is arranged on the refrigerant pipeline between an outlet of the outdoor heat exchanger and an inlet of the indoor heat exchanger, a second end of the recovery pipeline is communicated with an air suction port of the compressor, a first on-off valve is arranged on the recovery pipeline, and the first on-off valve is a normally-closed valve.

In a preferred embodiment of the above air conditioner, the first end of the recovery pipeline is disposed on the refrigerant pipeline between the throttling device and the inlet of the indoor heat exchanger.

In a preferred technical solution of the above air conditioner, the air conditioner further includes a second on-off valve, and the second on-off valve is disposed on the refrigerant pipeline between the first end of the recovery pipeline and the inlet of the indoor heat exchanger.

In a preferred technical solution of the above air conditioner, a high-pressure stop valve is disposed on a refrigerant pipeline between the outdoor heat exchanger and the indoor heat exchanger, and the second stop valve is disposed on the refrigerant pipeline between the first end of the recovery pipeline and the high-pressure stop valve.

In a preferred technical solution of the above air conditioner, the air conditioner further includes a third shutoff valve, and the third shutoff valve is disposed on the refrigerant pipeline between the outlet of the indoor heat exchanger and the four-way valve.

In a preferred technical scheme of the air conditioner, a low-pressure stop valve is arranged on a refrigerant pipeline between the indoor heat exchanger and the four-way valve, and the third stop valve is arranged on the refrigerant pipeline between the low-pressure stop valve and the four-way valve.

In a preferred technical solution of the above air conditioner, the first on-off valve, the second on-off valve and the third on-off valve are all solenoid valves.

In the preferable technical scheme of the air conditioner, the compressor is provided with a liquid storage device, a filter screen is arranged in the liquid storage device, the second end of the recovery pipeline is communicated with an inlet of the liquid storage device, and an outlet of the liquid storage device is communicated with an air suction port of the compressor.

In a preferred embodiment of the above air conditioner, the first end of the recovery pipeline is disposed on the refrigerant pipeline between the outlet of the outdoor heat exchanger and the throttling device.

In a preferred embodiment of the air conditioner, the throttle device is an electronic expansion valve.

It should be noted that, in the preferred technical scheme of this application, the air conditioner includes compressor, cross valve, outdoor heat exchanger, throttling arrangement and indoor heat exchanger through refrigerant tube coupling, and the air conditioner still includes the recovery pipeline, and the first end of recovery pipeline sets up on the refrigerant tube between the export of outdoor heat exchanger and the import of indoor heat exchanger, and the second end of recovery pipeline communicates with the induction port of compressor, is provided with first on-off valve on the recovery pipeline, and first on-off valve is the normally closed valve.

Through set up the recovery pipeline in the air conditioner, this application can utilize the recovery pipeline to reduce the flow stroke of high temperature refrigerant, reduce the pressure drop, improve the oil return effect in the oil return process of carrying out indoor heat exchanger and outdoor heat exchanger.

Drawings

The air conditioner of the present application is described below with reference to the accompanying drawings. In the drawings:

fig. 1 is a diagram of a refrigeration system of a first embodiment of an air conditioner of the present application;

fig. 2 is a diagram of a heating system of a first embodiment of an air conditioner according to the present application;

FIG. 3 is a diagram of a refrigeration system of a second embodiment of the air conditioner of the present application;

fig. 4 is a diagram of a refrigeration system of a third embodiment of the air conditioner of the present application;

fig. 5 is a diagram of a heating system of a third embodiment of the air conditioner of the present application;

fig. 6 is a diagram of a refrigeration system of a fourth embodiment of the air conditioner of the present application.

List of reference numerals

1. A compressor; 2. a four-way valve; 3. an outdoor heat exchanger; 4. a throttling device; 5. an indoor heat exchanger; 6. a refrigerant pipeline; 7. a recovery pipeline; 8. a first on-off valve; 9. a second on-off valve; 10. a third shutoff valve; 11. a high pressure stop valve; 12. a low pressure stop valve; 13. a reservoir.

Detailed Description

Preferred embodiments of the present application are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principles of the present application, and are not intended to limit the scope of protection of the present application.

It should be noted that the terms "first," "second," and "third" in the description of the present application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

It should also be noted that, in the description of the present application, unless explicitly stated or limited otherwise, the term "connected" is to be understood broadly, for example, it may be a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those skilled in the art as the case may be.

Example 1

First, referring to fig. 1 and 2, a first embodiment of an air conditioner of the present application will be briefly described. Fig. 1 is a diagram of a refrigeration system of a first embodiment of an air conditioner of the present application;

fig. 2 is a diagram of a heating system of a first embodiment of an air conditioner according to the present application.

As shown in fig. 1, in order to solve the problem of poor oil return effect of the existing oil return method, the air conditioner of the present application includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a throttling device 4 and an indoor heat exchanger 5, which are connected by a refrigerant pipeline 6. It should be noted that the specific connection mode and operation principle of the air conditioner through the refrigerant pipeline 6 belong to the common general knowledge in the art, and are not described in detail in this application.

Particularly, the air conditioner of this application still includes recovery pipeline 7, and the first end of recovery pipeline 7 sets up on refrigerant pipeline 6 between the export of outdoor heat exchanger 3 and the import of indoor heat exchanger 5, and the second end of recovery pipeline 7 communicates with the induction port of compressor 1, is provided with first on-off valve 8 on the recovery pipeline 7, and first on-off valve 8 is the normally closed valve.

Taking the oil return operation of the outdoor heat exchanger 3 as an example, when the oil return operation is performed, the on-off valve can be opened to enable the air conditioner to operate in the refrigeration mode, and the high-temperature and high-pressure refrigerant discharged by the compressor 1 rapidly flows in the outdoor air-exchange coil pipe, so that the coil pipe of the outdoor heat exchanger 3 is flushed, the engine oil on the inner wall of the coil pipe is flushed down, and directly returns to the inside of the compressor 1 through the recovery pipeline 7 along with the refrigerant, and the engine oil is recovered.

Through set up recovery pipeline 7 in the air conditioner, this application can utilize recovery pipeline 7 to reduce the flow stroke of high temperature refrigerant, reduce the pressure drop, improve the oil return effect at the in-process of returning oil of carrying out indoor heat exchanger 5 and outdoor heat exchanger 3.

Next, with further reference to fig. 1 and 2, a first embodiment of the air conditioner of the present application will be described in detail.

Referring to fig. 1, in a more preferred embodiment, the air conditioner includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a throttle device 4, a high-pressure cutoff valve 11, an indoor heat exchanger 5, a low-pressure cutoff valve 12, and an accumulator 13. The exhaust port of the compressor 1 is communicated with the P interface of the four-way valve 2 through a refrigerant pipeline 6, the C interface of the four-way valve 2 is communicated with the inlet of the outdoor heat exchanger 3 through the refrigerant pipeline 6, the outlet of the outdoor heat exchanger 3 is communicated with one port of the throttling device 4 through the refrigerant pipeline 6, the other port of the throttling device 4 is communicated with one end of the high-pressure stop valve 11 through the refrigerant pipeline 6, the other end of the high-pressure stop valve 11 is communicated with the inlet of the indoor heat exchanger 5 through the refrigerant pipeline 6, the outlet of the indoor heat exchanger 5 is communicated with one end of the low-pressure stop valve 12 through the refrigerant pipeline 6, the other end of the low-pressure stop valve 12 is communicated with the E interface of the four-way valve 2 through the refrigerant pipeline 6, the S interface of the four-way valve 2 is communicated with the inlet of the liquid accumulator 13 through the refrigerant pipeline 6, and the outlet of the liquid accumulator 13 is communicated with the suction port of the compressor 1 through the pipeline. The throttling means 4 is preferably an electronic expansion valve, and the high pressure stop valve 11 and the low pressure stop valve 12 are preferably manual valves, and the high pressure stop valve 11 and the low pressure stop valve 12 are used for sealing the refrigerant in the refrigerant pipeline 6 during installation and maintenance to avoid refrigerant leakage. A filter screen is arranged in the liquid storage device 13, and the liquid storage device 13 can play roles in storing refrigerants, separating refrigerant gas and liquid, filtering oil stains, silencing, buffering the refrigerants and the like.

The air conditioner further comprises a recovery pipeline 7 and a first on-off valve 8, the recovery pipeline 7 is a copper pipe with a smooth inner wall, the first end of the copper pipe is arranged on a refrigerant pipeline 6 between the throttling device 4 and the high-pressure stop valve 11, and the second end of the copper pipe is arranged on the refrigerant pipeline 6 between an S interface of the four-way valve 2 and an inlet of the liquid storage device 13. The first on-off valve 8 is preferably a solenoid valve which is in communication connection with the controller of the air conditioner to receive the opening and closing signal issued by the controller. Of course, the first on-off valve 8 may be an electrically controlled valve such as an electronic expansion valve.

Through set up recovery pipeline 7 in the air conditioner, this application can be in the oil return in-process of carrying out indoor heat exchanger 5 and outdoor heat exchanger 3, utilize recovery pipeline 7 to realize the recovery to refrigerator oil, realize that high temperature high pressure refrigerant is scouring away the back to one in indoor heat exchanger 5 and outdoor heat exchanger 3, need not to pass through another once more, but directly take the greasy dirt back to and retrieve in reservoir 13 and filter, then discharge through compressor 1 compression once more, the flow stroke of high temperature refrigerant has been reduced, reduce the on-the-way pressure drop, improve the oil return effect. Through the setting of reservoir 13, can filter the refrigerator oil of retrieving, avoid the impurity in the refrigerator oil to continue to participate in the refrigerant circulation.

Next, referring to fig. 1 and 2, a possible oil return process of the indoor heat exchanger 5 and the outdoor heat exchanger 3 in the present embodiment will be described.

As shown in fig. 1, when the outdoor heat exchanger 3 is returned, the electronic expansion valve is controlled to be opened to the maximum opening degree, the first on-off valve 8 is controlled to be opened, and the air conditioner is controlled to operate in the cooling mode. The flow direction of the refrigerant is shown as an arrow in fig. 1, the high-temperature and high-pressure refrigerant discharged by the compressor 1 enters the coil pipe of the outdoor heat exchanger 3 after passing through the P connector and the C connector of the four-way valve 2, the coil pipe is washed, oil stains on the coil pipe are washed away and discharged out of the outdoor heat exchanger 3 along with the refrigerant, the refrigerant mixed with the oil stains directly returns to the liquid reservoir 13 after passing through the electronic expansion valve and the recovery pipeline 7, the liquid reservoir 13 filters the oil stains, and the filtered refrigerant returns to the inside of the compressor 1 to continue to circulate.

As shown in fig. 2, when the indoor heat exchanger 5 is returned, the electronic expansion valve is controlled to be closed to the minimum opening degree, the first on-off valve 8 is controlled to be opened, and the air conditioner is controlled to operate in the heating mode. The flow direction of the refrigerant is as shown by the arrow in fig. 2, the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the coil pipe of the indoor heat exchanger 5 after passing through the P interface and the E interface of the four-way valve 2, the coil pipe is washed, oil stains on the coil pipe are washed away and discharged out of the indoor heat exchanger 5 along with the refrigerant, the refrigerant mixed with the oil stains directly returns to the liquid reservoir 13 after passing through the recovery pipeline 7, the liquid reservoir 13 filters the oil stains, and the filtered refrigerant returns to the inside of the compressor 1 to continue to circulate.

Example 2

Referring next to fig. 3, a second embodiment of the present application will be described. Fig. 3 is a diagram of a refrigeration system of a second embodiment of the air conditioner of the present application.

As shown in fig. 3, embodiment 2 of the present application differs from embodiment 1 in that a first end of a recovery line 7 is provided in a refrigerant line 6 between an outlet of an outdoor heat exchanger 3 and an expansion device 4, without changing the other installation manner.

Accordingly, the present embodiment 2 is slightly different from the embodiment 1 in the control manner when the oil return operation is performed. Specifically, when the outdoor heat exchanger 3 is subjected to oil return, the electronic expansion valve is controlled to be closed to the minimum opening degree, the first on-off valve 8 is controlled to be opened, and the air conditioner is controlled to operate in a refrigeration mode; when oil is returned to the indoor heat exchanger 5, the electronic expansion valve is controlled to be opened to the maximum opening degree, the first on-off valve 8 is controlled to be opened, and the air conditioner is controlled to operate in a heating mode. In the oil return process, the flow manner of the refrigerant is substantially the same as that in embodiment 1, and is not described herein.

Example 3

Next, a third embodiment of the present application will be described with reference to fig. 4 and 5. Fig. 4 is a diagram of a refrigeration system of a third embodiment of the air conditioner of the present application; fig. 5 is a diagram of a heating system of a third embodiment of the air conditioner of the present application.

As shown in fig. 4 and 5, on the premise that other installation modes are not changed, embodiment 3 of the present application is different from embodiment 1 in that the air conditioner further includes a second on-off valve 9 and a third on-off valve 10, and the second on-off valve 9 and the third on-off valve 10 are normally open valves. The second on-off valve 9 is disposed on the refrigerant pipeline 6 between the first end of the recovery pipeline 7 and the high-pressure stop valve 11, and the third on-off valve 10 is disposed on the refrigerant pipeline 6 between the low-pressure stop valve 12 and the E port of the four-way valve 2. Preferably, the second on-off valve 9 and the third on-off valve 10 are electromagnetic valves, and both of the electromagnetic valves are in communication connection with a controller of the air conditioner to respectively receive opening and closing signals sent by the controller. Of course, one or both of them may be electrically controlled valves such as electronic expansion valves.

Through the setting of second on-off valve 9 and third on-off valve 10, can further promote the oil return effect of air conditioner. Specifically, by controlling the opening and closing of the second cut-off valve 9 and the third cut-off valve 10, the flow pressure of the refrigerant during the oil return process can be increased, and the oil return effect can be improved. In addition, by controlling the opening and closing of the second on-off valve 9 and the third on-off valve 10, the refrigerant can be recovered first during oil return operation, so that the pressure of the refrigerant is increased, the flow impact force of the refrigerant in the oil return process is increased, and the oil return effect is improved.

Next, referring to fig. 4 and 5, a possible oil return process of the indoor heat exchanger 5 and the outdoor heat exchanger 3 of the present embodiment will be described.

As shown in fig. 4, when the oil return operation is performed on the indoor heat exchanger 5, the air conditioner is controlled to operate the refrigeration mode, the electronic expansion valve is controlled to be opened to the minimum opening degree, the first on-off valve 8 and the second on-off valve 9 are controlled to be closed, and the third on-off valve 10 is controlled to be closed after delaying for 1min, so that the refrigerant is recovered into the outdoor heat exchanger 3; referring to fig. 5, after the refrigerant is recovered, the first on-off valve 8, the second on-off valve 9 and the third on-off valve 10 are opened at the same time, the operation mode of the air conditioner is controlled to be switched to a heating mode, at this time, the flow direction of the refrigerant is as shown by arrows in fig. 5, the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the coil pipe of the indoor heat exchanger 5 after passing through the P interface and the E interface of the four-way valve 2 and the third on-off valve 10, the coil pipe is washed, oil stains on the coil pipe are washed away and discharged out of the indoor heat exchanger 5 along with the refrigerant, the refrigerant mixed with the oil stains directly returns to the liquid reservoir 13 after passing through the second on-off valve 9 and the recovery pipeline 7, the liquid reservoir 13 filters the oil stains, and the filtered refrigerant returns to the inside of the compressor 1 to continue to circulate.

As shown in fig. 5, when the oil return operation is performed on the outdoor heat exchanger 3, the air conditioner is controlled to operate in the heating mode, the electronic expansion valve is controlled to be closed to the minimum opening degree, the first on-off valve 8 is controlled to be opened, the second on-off valve 9 is controlled to be closed, and the third on-off valve 10 is controlled to be closed after delaying for 1min, so that the refrigerant is recovered into the indoor heat exchanger 5; referring to fig. 4, after the refrigerant is recovered, the first on-off valve 8, the second on-off valve 9, the third on-off valve 10 and the electronic expansion valve are opened at the same time, the operation mode of the air conditioner is controlled to be switched to the refrigeration mode, at the moment, the flow direction of the refrigerant is as shown by arrows in fig. 4, the high-temperature and high-pressure refrigerant discharged from the compressor 1 enters the coil pipe of the outdoor heat exchanger 3 after passing through the P interface and the C interface of the four-way valve 2, the coil pipe is washed, oil stains on the coil pipe are washed away and discharged out of the outdoor heat exchanger 3 along with the refrigerant, the refrigerant mixed with the oil stains directly returns to the liquid reservoir 13 after passing through the electronic expansion valve and the recovery pipeline 7, the liquid reservoir 13 filters the oil stains, and the filtered refrigerant returns to the inside of the compressor 1 to continue to circulate.

Example 4

Referring next to fig. 6, a fourth embodiment of the present application will be described. Fig. 6 is a diagram of a refrigeration system of a fourth embodiment of the air conditioner of the present application.

As shown in fig. 6, embodiment 4 of the present application differs from embodiment 3 in that a first end of a recovery pipeline 7 is provided in a refrigerant pipeline 6 between an outlet of an outdoor heat exchanger 3 and an expansion device 4, without changing other installation manners.

Accordingly, the control manner of the present embodiment 4 is slightly different from that of the embodiment 3 when the oil return operation is performed. Specifically, when oil is returned to the indoor heat exchanger 5, firstly, the air conditioner is controlled to operate in a refrigeration mode, the electronic expansion valve is controlled to be closed to the minimum opening degree, the first on-off valve 8 and the second on-off valve 9 are controlled to be closed, and the third on-off valve 10 is delayed for 1min to be closed, so that the refrigerant is recovered to the outdoor heat exchanger 3; after the refrigerant is recovered, the first on-off valve 8, the second on-off valve 9, the third on-off valve 10 and the electronic expansion valve are opened simultaneously, and the operation mode of the air conditioner is controlled to be switched to the heating mode. When oil return is carried out on the outdoor heat exchanger 3, firstly, the air conditioner is controlled to operate in a heating mode, the electronic expansion valve is controlled to be closed to the minimum opening degree, the first on-off valve 8 is controlled to be opened, the second on-off valve 9 is controlled to be closed, and the third on-off valve 10 is delayed for 1min to be closed, so that the refrigerant is recovered into the indoor heat exchanger 5; after the refrigerant is recovered, the first on-off valve 8, the second on-off valve 9 and the third on-off valve 10 are opened simultaneously, and the operation mode of the air conditioner is controlled to be switched to the refrigeration mode. In the oil return process, the flow manner of the refrigerant is substantially the same as that in embodiment 3, and is not described herein.

It should be noted that, although the present application is described above with reference to four examples, the above-mentioned embodiments are only used for illustrating the principle of the present application and are not intended to limit the protection scope of the present application. Without departing from the principles of the present application, those skilled in the art can adjust the setting manner, so that the present application can be applied to more specific application scenarios.

For example, in an alternative embodiment, the presence or absence of the second on-off valve 9 and the third on-off valve 10 can be selected by a person skilled in the art according to a specific application scenario, for example, only one of the second on-off valve 9 and the third on-off valve 10 may be provided, and the like, on the premise that the first on-off valve 8 is ensured to be provided.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims of the present application, any of the claimed embodiments may be used in any combination.

So far, the technical solutions of the present application have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present application is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the present application, and the technical scheme after the changes or substitutions will fall into the protection scope of the present application.

Claims

1. An air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger which are connected through refrigerant pipelines,

the air conditioner further comprises a recovery pipeline, wherein the first end of the recovery pipeline is arranged on the refrigerant pipeline between the outlet of the outdoor heat exchanger and the inlet of the indoor heat exchanger, the second end of the recovery pipeline is communicated with the air suction port of the compressor, a first on-off valve is arranged on the recovery pipeline, and the first on-off valve is a normally-closed valve.

2. The air conditioner according to claim 1, wherein a first end of the recovery pipeline is disposed on the refrigerant pipeline between the throttling device and the inlet of the indoor heat exchanger.

3. The air conditioner as claimed in claim 2, further comprising a second on-off valve disposed on the refrigerant pipe between the first end of the recovery pipe and the inlet of the indoor heat exchanger.

4. The air conditioner according to claim 3, wherein a high pressure stop valve is provided on a refrigerant pipe between the outdoor heat exchanger and the indoor heat exchanger, and the second shut-off valve is provided on the refrigerant pipe between the first end of the recovery pipe and the high pressure stop valve.

5. The air conditioner according to claim 3, further comprising a third shut-off valve disposed on the refrigerant pipeline between the outlet of the indoor heat exchanger and the four-way valve.

6. The air conditioner according to claim 5, wherein a low pressure stop valve is provided on a refrigerant pipe between the indoor heat exchanger and the four-way valve, and the third stop valve is provided on the refrigerant pipe between the low pressure stop valve and the four-way valve.

7. The air conditioner according to claim 6, wherein the first on-off valve, the second on-off valve and the third on-off valve are all solenoid valves.

8. The air conditioner according to claim 1, wherein the compressor is provided with a reservoir, a filter screen is arranged in the reservoir, a second end of the recovery pipeline is communicated with an inlet of the reservoir, and an outlet of the reservoir is communicated with a suction port of the compressor.

9. The air conditioner according to claim 1, wherein a first end of the recovery pipe is disposed on the refrigerant pipe between the outlet of the outdoor heat exchanger and the throttling device.

10. The air conditioner of claim 1, wherein the throttling device is an electronic expansion valve.