WO2018233457A1

WO2018233457A1 - Air conditioner and defrosting method for outdoor unit thereof

Info

Publication number: WO2018233457A1
Application number: PCT/CN2018/088849
Authority: WO
Inventors: 杨中锋; 王彦生; 曾福祥; 刘超超
Original assignee: 青岛海尔空调器有限总公司
Priority date: 2017-06-22
Filing date: 2018-05-29
Publication date: 2018-12-27
Also published as: CN107726536A

Abstract

An air conditioner and a defrosting method for an outdoor unit thereof. After an air conditioner enters an outdoor unit defrosting mode, a throttling device (500) is controlled to reduce the flow rate of a refrigerant at an outlet of an outdoor unit heat exchanger (200), and the heat exchange amount of the outdoor unit is reduced. In this way, the exhaust temperature of a compressor (100) would rise quickly, so that the temperature of the refrigerant reaching a condenser is relatively high. Thus, the defrosting speed and the defrosting effect are improved. In addition, the compressor (100) has a shutdown protection function; when the index temperature is too high, it means that the exhaust temperature of the compressor (100) is too high, and the compressor (100) would be automatically shut down to prevent the air conditioner from failing. Therefore, according to the method of the present invention, when the index temperature is above a first preset temperature, the flow rate at the refrigerant outlet of the outdoor unit heat exchanger (200) would be increased to appropriately reduce the exhaust temperature of the compressor (100), thereby preventing the compressor (100) from being shut down and the defrosting process from being interrupted.

Description

Air conditioner and outdoor unit defrosting method thereof

Technical field

The invention relates to the field of air conditioning, in particular to an air conditioner and a defrosting method thereof.

Background technique

When the air conditioner is heated in winter, the temperature of the condenser is low, and the surface thereof is prone to frost. Therefore, after the air conditioner is heated for a while, the condenser needs to be defrosted. After the air conditioner receives the start of the defrost signal, the four-way valve is reversed, and the refrigerant flows from the compressor to the condenser and then to the evaporator and then returns to the compressor. Similar to the cooling mode, the "high temperature" gas refrigerant discharged by the press is condensed. In order to achieve the purpose of defrosting and defrosting.

However, when the air conditioner is heating in winter, the defrosting may not be complete under the condition that the condenser is operated in an ultra-low temperature environment for a long time. Because in the ultra-low temperature environment (below -7 °C), the temperature of the gaseous refrigerant discharged from the fixed-frequency compressor is not high, and may be only about 30 °C. Therefore, the temperature of the refrigerant may be lower when entering the condenser, even reaching below 0 °C. In this case, the defrost speed is slow and may not be clean. If the frost is not fully condensed, frost accumulation may occur and even the surface of the heat exchanger may freeze, which seriously affects the heat exchange effect of the condenser.

Summary of the invention

In view of the above problems, the present invention has been made in order to provide an air conditioner and an outdoor unit defrosting method thereof that overcome the above problems or at least partially solve the above problems.

An object of the present invention is to improve the defrosting efficiency.

Another object of the invention is to prevent a protective shutdown of the compressor.

Another object of the present invention is to maintain the refrigerant in the outdoor unit heat exchanger within a certain temperature range.

In one aspect, the present invention provides a defrosting method for an outdoor unit of an air conditioner, the air conditioner comprising a refrigerant circulation system formed by sequentially connecting a compressor, an outdoor unit heat exchanger and an indoor unit heat exchanger, the method comprising: receiving a defrosting signal After that, the air conditioner is controlled to enter a cooling state, and the defrosting process is started; the flow rate of the refrigerant outlet of the outdoor heat exchanger is reduced to gradually increase the temperature of the indicator; the temperature of the indicator is detected in real time, and whether the temperature of the indicator is higher than the first preset temperature; if so, Increasing the flow rate of the refrigerant outlet of the outdoor heat exchanger to gradually reduce the index temperature; wherein the index temperature includes: the exhaust temperature of the compressor or the middle portion of the outdoor heat exchanger or the refrigerant outlet temperature of the outdoor heat exchanger.

Optionally, after the step of increasing the flow rate of the refrigerant outlet of the outdoor heat exchanger to gradually reduce the temperature of the indicator, the method further comprises: detecting the temperature of the indicator in real time, and determining whether the temperature of the indicator is lower than the second preset temperature; and the second preset temperature It is smaller than the first preset temperature; if so, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger is reduced again, and the subsequent steps are repeated to keep the control index temperature between the first preset temperature and the second preset temperature.

Optionally, one end of the refrigerant outlet of the outdoor unit heat exchanger is provided with a shut-off valve, wherein the step of reducing the flow rate of the refrigerant outlet of the outdoor unit heat exchanger comprises: reducing the opening degree of the shut-off valve to reduce the flow rate of the refrigerant; and increasing the heat exchange of the outdoor unit The step of the flow of the refrigerant outlet includes increasing the degree of opening of the shutoff valve to increase the flow rate of the refrigerant.

Optionally, the defrosting method further includes: after the defrosting process ends, restoring the opening degree of the shut-off valve in the normal heating state of the air conditioner; stopping the compressor and stopping the air-conditioning cooling.

Optionally, the step of stopping the compressor and stopping the air conditioning and cooling further comprises: after waiting for the preset time, the compressor is restarted to enter the air conditioning heating state.

In another aspect, the present invention also provides an air conditioner comprising: a refrigerant circulation system formed by sequentially connecting a compressor, an outdoor unit heat exchanger and an indoor unit heat exchanger; and a throttle device for use in the defrosting process, The flow rate of the refrigerant outlet of the outdoor heat exchanger is controlled; the temperature detecting device is used for detecting the temperature of the indicator, and the temperature of the indicator includes: the exhaust temperature of the compressor or the intermediate part of the heat exchanger of the outdoor unit or the outlet temperature of the refrigerant of the outdoor unit heat exchanger And the main control device configured to receive the defrosting signal, control the air conditioner to enter the cooling state, and start the defrosting process; wherein the throttling device is further configured to reduce the flow rate of the refrigerant outlet of the outdoor heat exchanger to gradually increase the index temperature When the index temperature is higher than the first preset temperature, increase the flow rate of the refrigerant outlet of the outdoor unit heat exchanger to gradually lower the index temperature.

Optionally, the throttling device is further configured to: when the indicator temperature is lower than the second preset temperature, reduce the flow rate of the refrigerant outlet of the outdoor heat exchanger again, to control the indicator temperature to remain at the first preset temperature and Between two preset temperatures.

Optionally, the throttling device comprises: a shut-off valve disposed at one end of the refrigerant outlet of the outdoor heat exchanger, configured to reduce or increase the flow of the refrigerant by adjusting the degree of opening thereof.

Optionally, the throttling device is further configured to restore the opening degree of the shut-off valve in the normal heating state of the air conditioner after the defrosting process ends; the main control device is further configured to control the compressor to stop and stop the air conditioning and cooling.

Optionally, the master device is further configured to wait for a preset time to control the compressor to re-enter the air conditioning heating state.

In the method of the present invention, after the air conditioner enters the defrosting mode of the outdoor unit, the throttle device is controlled to reduce the flow rate of the refrigerant at the outlet of the outdoor heat exchanger, and the heat exchange amount of the outdoor unit is reduced. In this way, the exhaust temperature of the compressor rises rapidly, so that the temperature of the refrigerant reaching the condenser is relatively high, which improves the defrosting effect of the defrosting speed. In addition, the compressor generally has a shutdown protection function, specifically when the indicator temperature is too high, which means that the exhaust temperature of the compressor is too high, the compressor will automatically stop, to avoid malfunction of the air conditioner. Therefore, when the index temperature exceeds the first preset temperature, the method of the present invention increases the flow rate of the refrigerant outlet of the outdoor heat exchanger to appropriately reduce the exhaust temperature of the compressor to avoid excessive exhaust gas temperature and compressor shutdown. Causes the defrosting process to be interrupted.

Further, the method of the present invention further includes: if the index temperature is lower than the second preset temperature, reducing the flow rate of the refrigerant outlet of the outdoor unit heat exchanger again to increase the index temperature. The method of the invention stabilizes the temperature of the indicator between the first preset temperature and the second preset temperature by repeatedly adjusting the throttle device, so that the refrigerant flowing through the heat exchanger of the outdoor unit is maintained in a relatively high temperature range, thereby It is easier to melt the frost on the surface of the heat exchanger. At the same time, during the defrosting process, the exhaust temperature of the compressor is more stable, preventing the exhaust gas temperature or the temperature fluctuation of the refrigerant inside the heat exchanger from being severe, which affects the normal operation of the air conditioner.

The above as well as other objects, advantages and features of the present invention will become apparent to those skilled in the <

DRAWINGS

Some specific embodiments of the present invention will be described in detail, by way of example, and not limitation, The same reference numbers in the drawings identify the same or similar parts. Those skilled in the art should understand that the drawings are not necessarily drawn to scale. In the figure:

1 is a schematic view of a refrigerant flow path of an air conditioner according to an embodiment of the present invention;

2 is a schematic block diagram of an air conditioner in accordance with one embodiment of the present invention;

3 is a schematic diagram of a defrosting method of an outdoor unit of an air conditioner according to an embodiment of the present invention;

4 is a flow chart of a defrosting method of an outdoor unit of an air conditioner according to an embodiment of the present invention;

Fig. 5 is a flow chart showing a defrosting method of an outdoor unit of an air conditioner according to another embodiment of the present invention.

Detailed ways

The embodiment of the present invention first provides an air conditioner indoor unit, including: a compressor 100, an outdoor unit heat exchanger 200, an indoor unit heat exchanger 300, a throttle device 500, a temperature detecting device 110, and a main control device 400.

The compressor 100, the outdoor unit heat exchanger 200, and the indoor unit heat exchanger 300 are sequentially connected to form a refrigerant circulation system. Refrigeration cycle systems for air conditioners are known to those skilled in the art and will not be described in detail herein.

The throttle device 500 is for controlling the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 during the defrosting process. In this embodiment, the throttling device 500 may be a shut-off valve 500 disposed at one end of the refrigerant outlet of the outdoor unit heat exchanger 200 (the above-mentioned refrigerant outlet refers to heat exchange in the outdoor unit defrosting process, or indoor unit heat exchange) The device 300 is in a cooling state, and is a refrigerant outlet of the outdoor unit heat exchanger 200. The shutoff valve 500 has a passage for the refrigerant to flow inside and a spool for at least partially closing the passage. In the defrosting state, the air conditioner can change the opening and closing degree of the passage of the shut-off valve 500 by adjusting the position of the spool, thereby adjusting the flow rate of the refrigerant outlet of the outdoor heat exchanger 200, and in the case of general cooling or heating, the shut-off valve The 500 refrigerant passage is kept fully open. In still other embodiments of the present invention, the outdoor unit heat exchanger 200 includes a supercooling tube, and the throttling device 500 may be an expansion valve disposed on the supercooling tube, and the outdoor unit heat exchanger 200 is indirectly reduced by adjusting the expansion valve opening degree. Refrigerant flow at the outlet of the refrigerant.

The temperature detecting device 110 is disposed at an exhaust port of the compressor 100 for detecting an index temperature. The above index temperature includes the exhaust temperature of the compressor 100 or the intermediate portion temperature of the outdoor unit heat exchanger 200 or the refrigerant outlet temperature of the outdoor unit heat exchanger 200. In the present embodiment, the index temperature is the exhaust temperature of the compressor 100, and the temperature detecting device 110 may include a temperature sensor disposed at the exhaust port of the compressor 100 for detecting the exhaust temperature of the compressor 100. In some alternative embodiments, the indicator temperature may also be the temperature of the intermediate portion of the coil of the outdoor unit heat exchanger 200 or the temperature of the refrigerant outlet. It will be understood by those skilled in the art that the exhaust temperature of the compressor 100 is related to the temperature of the refrigerant in the outdoor unit heat exchanger 200. Generally, the higher the exhaust temperature of the compressor 100, the inside of the outdoor unit heat exchanger 200 The temperature of the refrigerant is higher. Therefore, the temperature of the intermediate portion of the outdoor unit heat exchanger 200 or the temperature of the refrigerant outlet can be used as an index temperature instead of the temperature of the refrigerant outlet.

The throttling device 500 is configured to reduce the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 during the defrosting process to gradually increase the index temperature; and to increase the outdoor unit exchange when the exhaust index temperature is higher than the first preset temperature The flow rate of the refrigerant outlet of the heat exchanger 200 is gradually lowered to the index temperature. In the present embodiment, the throttle device 500 is a shutoff valve 500, and the index temperature is the exhaust temperature of the compressor 100, and the first preset temperature may be 75 °C. In still other embodiments of the present invention, the index temperature may also be the intermediate portion temperature or the refrigerant outlet temperature of the outdoor unit heat exchanger 200, in which case the corresponding first predetermined temperature should be less than 75 °C.

In the present embodiment, the opening degree of the shutoff valve 500 is reduced during the defrosting period, the flow rate of the refrigerant is decreased, and the amount of heat exchange is lowered. Thus, the exhaust temperature of the compressor 100 is rapidly increased, so that the temperature of the refrigerant reaching the outdoor unit heat exchanger 200 is relatively high, and the defrosting effect of the defrosting speed is improved.

However, if the exhaust gas temperature of the compressor 100 continues to rise, the compressor 100 may be mechanically shut down, so when the exhaust gas temperature rises to the first preset temperature, it is necessary to appropriately increase the opening degree of the shutoff valve 500.

When the opening degree of the shutoff valve 500 is increased, the exhaust gas temperature of the compressor 100 is lowered, and when the exhaust gas temperature is lower than the second preset temperature, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 is again reduced. The exhaust gas temperature is controlled to be maintained between the first preset temperature and the second preset temperature. By controlling the switching state of the shutoff valve 500, the temperature of the refrigerant flowing through the outdoor unit heat exchanger 200 can be maintained at a relatively high temperature range at all times. The second preset temperature may be 60 °C.

Specifically, after operating for a period of time in the air-conditioning heating state, after the frost on the surface of the outdoor heat exchanger 200 reaches a certain level, the air conditioner stops heating and starts defrosting. When the defrosting signal is received, the compressor 100 and the fan are stopped, the heating is suspended, and the rear four-way valve 600 is reversed to the position of the cooling state, in preparation for starting the defrosting, at which time the shut-off valve 500 is in the fully open state. When the defrosting is started (that is, the indoor unit enters the cooling state), the shut-off valve 500 is first controlled to reduce the opening degree so that the refrigerant flow rate at the outlet of the outdoor unit heat exchanger 200 is lower than that in the normal cooling condition, and the compressor 100 is started after 5 s. run. Due to the significant throttling effect of the shut-off valve 500, the press exhaust temperature will rise rapidly and is significantly higher than the exhaust temperature of the compressor 100 in the normal cooling state of the air conditioner. When the temperature rises to 75 ° C, the control shut-off valve 500 increases the opening degree (if the exhaust gas temperature is too high, the compressor 100 will be protectively stopped, so that the defrosting cannot be continued), the exhaust gas temperature will drop, when it falls to At 60 ° C, the shut-off valve 500 again reduces the opening to increase the exhaust gas temperature, so that the cycle is repeated, so that the exhaust gas temperature is always in the high temperature range of 60-75 ° C, greatly improving the defrosting effect.

The main control device 400 is also configured to control the compressor 100 to stop and stop the air conditioning refrigeration after the defrosting process ends. The throttle device 500 is also configured to restore the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 in the heating state. When the preset defrost time is over, the defrost stops. At this time, regardless of the opening and closing state of the shutoff valve 500, the shutoff valve 500 is first fully opened, and the state of heating is restored to prevent the circulation of the refrigerant from being blocked. The heating is affected and the compressor 100 is then shut down.

The main control device 400 is further configured to wait for a preset time to control the compressor 100 to re-enter into the air conditioning heating state. After waiting for the preset time, the four-way valve 600 is switched to the heating state position, and the compressor 100 starts the fan operation and enters the normal heating mode, and the entire defrost cycle is completed.

3 is a schematic diagram of a defrosting method of an indoor unit of an air conditioner according to an embodiment of the present invention. The control method of this embodiment may generally include the following steps:

Step S302, after receiving the defrosting signal, control the air conditioner to enter a cooling state, and start defrosting. The above air conditioning refrigeration state is basically the same as that of the general air conditioner in the summer, that is, the refrigerant releases heat through the outdoor unit heat exchanger 200, and the cooling capacity is released through the indoor unit heat exchanger 300. However, there are some differences. In the above air conditioning refrigeration state, the indoor unit fan may not be opened to avoid blowing cold air into the room, which may affect the user. The defrost signal can be sent by the internal program of the air conditioner. For example, each time the air conditioner is heated for a certain period of time, the air conditioner sends a defrost command, and the main control panel controls the air conditioner to automatically enter the defrost mode. The defrost signal can also be transmitted by the user via the remote control.

In step S304, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 is reduced to gradually increase the index temperature. The above index temperature may include the exhaust temperature of the compressor 100 or the intermediate portion temperature of the outdoor unit heat exchanger 200 or the outdoor unit heat exchanger 200 refrigerant outlet temperature. The refrigerant flow is reduced, and the heat exchange capacity of the outdoor unit is reduced. Thus, the exhaust temperature of the compressor 100 and the associated index temperature will rise rapidly, so that the temperature of the refrigerant reaching the outdoor unit heat exchanger 200 is relatively increased, so that the high temperature refrigerant is more likely to melt the frost on the surface of the outdoor heat exchanger 200. Increases the defrosting speed and defrosting effect.

Step S306, detecting the indicator temperature in real time, and determining whether the index temperature is higher than the first preset temperature. In the present embodiment, the compressor 100 has a shutdown protection function. When the exhaust temperature of the compressor 100 is too high, the compressor 100 automatically stops to avoid malfunction of the air conditioner. Therefore, when the index temperature exceeds the first preset temperature, it is necessary to appropriately lower the exhaust temperature of the compressor 100 to avoid the compressor 100 from being shut down.

In step S308, if the result of the determination in step S306 is YES, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 is increased to gradually lower the index temperature. When the index temperature exceeds the first preset temperature, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 is increased, and the heat exchange amount of the outdoor unit is increased, so that the exhaust temperature of the compressor 100 and the related index temperature are lowered. If the result of the determination in step S306 is no, the waiting index temperature reaches the first preset temperature.

4 is a flow chart of a defrosting method of an indoor unit of an air conditioner according to an embodiment of the present invention. In the present embodiment, the expansion device 500 may be a shutoff valve 500 provided at one end of the refrigerant outlet of the outdoor unit heat exchanger 200. The shutoff valve 500 has an opening through which the refrigerant flows and a valve body for at least partially closing the opening. In the defrosting state, the air conditioner can change the opening and closing degree of the opening of the shutoff valve 500 by adjusting the position of the spool, thereby adjusting the flow rate of the refrigerant outlet of the outdoor heat exchanger 200, and in the case of general cooling or heating, the shutoff valve The 500 is kept fully open. The index temperature is selected from the exhaust temperature of the compressor 100. The control method performs the following steps in sequence:

Step S402, after receiving the defrosting signal, control the air conditioner to enter a cooling state, and start defrosting.

In step S404, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 is reduced to gradually increase the exhaust temperature of the compressor 100.

In step S406, it is determined whether the exhaust temperature of the compressor 100 is higher than the first preset temperature. The first preset temperature may be 75 °C.

In step S408, if the result of the determination in step S306 is YES, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 is increased to gradually lower the exhaust temperature of the compressor 100. If the result of the determination in the step S306 is NO, the exhaust gas temperature of the compressor 100 is awaited to reach the first preset temperature.

In step S410, it is determined whether the exhaust temperature of the compressor 100 is lower than the second preset temperature. If the result of the determination in step S410 is YES, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 is again reduced to gradually increase the exhaust temperature of the compressor 100. If the result of the determination in step S410 is NO, the compressor 100 is waited for the exhaust gas temperature to drop to the second preset temperature. The second preset temperature may be 60 °C.

In the defrosting method of the outdoor unit of the air conditioner of the present embodiment, the flow rate of the refrigerant at the outlet of the outdoor unit heat exchanger 200 is controlled by adjusting the opening degree of the shutoff valve 500. The exhaust gas temperature of the compressor 100 is always in a high temperature range of 60-75 ° C, so that the refrigerant flowing through the outdoor unit heat exchanger 200 is maintained in a relatively high temperature range, greatly improving the defrosting effect.

FIG. 5 is a flowchart of a defrosting method of an outdoor unit of an air conditioner according to another embodiment of the present invention, and the control method of the embodiment sequentially performs the following steps:

Step S502, after the defrosting process ends, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger 200 in the heating state is restored.

In step S504, the compressor 100 is stopped, and the air conditioning is stopped. When the preset defrost time is over, the defrost stops. At this time, regardless of the opening and closing state of the shutoff valve 500, the shutoff valve 500 is first fully opened, and the state of heating is restored to prevent the circulation of the refrigerant from being blocked. The heating is affected and the compressor 100 is then shut down.

Step S506, waiting for the preset time. Before entering the air conditioning heating state, it is necessary to wait for a preset time, so that the temperature of the outdoor unit heat exchanger 200 drops to a certain extent, and the four-way valve 600 is switched to the heating state again. In order to prevent the outdoor unit heat exchanger 200 from suddenly switching from heating to cooling, the temperature difference is too large to damage the coil.

In step S508, the compressor 100 is turned back on to enter the air conditioning heating state. The press starts the fan and the air conditioner re-enters the heating state.

In this regard, it will be appreciated by those skilled in the <RTIgt;the</RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; The content directly determines or derives many other variations or modifications consistent with the principles of the invention. Therefore, the scope of the invention should be understood and construed as covering all such other modifications or modifications.

Claims

A defrosting method for an outdoor unit of an air conditioner, the air conditioner comprising a refrigerant circulation system formed by sequentially connecting a compressor, an outdoor unit heat exchanger and an indoor unit heat exchanger, the method comprising:

After receiving the defrosting signal, controlling the air conditioner to enter a cooling state, and starting a defrosting process;

Reducing the flow rate of the refrigerant outlet of the outdoor heat exchanger to gradually increase the index temperature;

Detecting the temperature of the indicator in real time, and determining whether the temperature of the indicator is higher than the first preset temperature;

If yes, increase the flow rate of the refrigerant outlet of the outdoor unit heat exchanger to gradually reduce the temperature of the indicator;

The indicator temperature includes: an exhaust temperature of the compressor or an intermediate portion temperature of the outdoor unit heat exchanger or an outdoor unit heat exchanger refrigerant outlet temperature.
The defrosting method according to claim 1, further comprising: after increasing the flow rate of the refrigerant outlet of the outdoor unit heat exchanger to gradually lower the temperature of the index;

Detecting the temperature of the indicator in real time, and determining whether the temperature of the indicator is lower than a second preset temperature; the second preset temperature is less than the first preset temperature;

If so, the flow rate of the refrigerant outlet of the outdoor unit heat exchanger is reduced again, and the subsequent steps are repeated to control the index temperature to remain between the first preset temperature and the second preset temperature.
The defrosting method according to claim 2, wherein one end of the refrigerant outlet of the outdoor unit heat exchanger is provided with a shutoff valve, wherein

The steps of reducing the flow rate of the refrigerant outlet of the outdoor unit heat exchanger include:

Reducing the degree of opening of the shut-off valve to reduce the flow rate of the refrigerant;

The step of increasing the flow rate of the refrigerant outlet of the outdoor unit heat exchanger includes:

The degree of opening of the shut-off valve is increased to increase the flow rate of the refrigerant.
The defrosting method according to claim 3, further comprising:

After the defrosting process is finished, restoring the opening degree of the shut-off valve in the normal heating state of the air conditioner;

The compressor stops and the air conditioning is stopped.
The defrosting method according to claim 4, wherein the step of stopping the compressor and stopping the cooling of the air conditioner further comprises:

After waiting for the preset time, the compressor is turned back on and enters the air conditioning heating state.
An air conditioner comprising:

a refrigerant circulation system formed by sequentially connecting a compressor, an outdoor unit heat exchanger and an indoor unit heat exchanger;

a throttling device for controlling a flow rate of the refrigerant outlet of the outdoor heat exchanger during the defrosting process;

a temperature detecting device, configured to detect an indicator temperature, the indicator temperature comprising: an exhaust temperature of the compressor or an intermediate portion temperature of the outdoor unit heat exchanger or an outdoor unit heat exchanger refrigerant outlet temperature;

The main control device is configured to, after receiving the defrosting signal, control the air conditioner to enter a cooling state, and start a defrosting process;

The throttling device is further configured to reduce a flow rate of the refrigerant outlet of the outdoor heat exchanger to gradually increase the temperature of the indicator; and increase the outdoor when the indicator temperature is higher than the first preset temperature The flow rate of the refrigerant outlet of the heat exchanger to gradually reduce the temperature of the indicator.
The air conditioner according to claim 6, wherein said throttle device is further configured to:

When the indicator temperature is lower than the second preset temperature, reducing the flow rate of the outdoor heat exchanger refrigerant outlet to control the indicator temperature to remain at the first preset temperature and the second Preset between temperatures.
The air conditioner according to claim 7, wherein said throttle device comprises:

The shutoff valve is disposed at one end of the refrigerant outlet of the outdoor unit heat exchanger, and is configured to reduce or increase the flow rate of the refrigerant by adjusting the degree of opening of the outdoor unit.
The air conditioner according to claim 8, wherein

The throttling device is further configured to restore the opening degree of the shut-off valve in a normal heating state of the air conditioner after the defrosting process ends;

The main control device is further configured to control the compressor to stop and stop the air conditioning and cooling.
The air conditioner according to claim 9, wherein

The main control device is further configured to wait for a preset time to control the compressor to re-enter into the air conditioning heating state.