KR20190000584A - Air conditioner - Google Patents

Abstract

According to an embodiment of the present invention, an air conditioner comprises: a cooling cycle having a compressor, an outdoor heat exchanger, an expansion apparatus, and an indoor heat exchanger; an outdoor unit in which the compressor, the outdoor heat exchanger, and the expansion apparatus are arranged, and a high pressure service valve and a low pressure service valve are provided; an indoor unit in which the indoor heat exchanger is arranged; a high pressure opening and closing valve arranged between the outdoor heat exchanger and the high pressure service valve of the cooling cycle; a low pressure opening and closing valve arranged between the low pressure service valve and the compressor of the cooling cycle; a pressure sensor installed in the cooling cycle, and measuring pressure of refrigerant; and a controller receiving the measured pressure of the pressure sensor, and controlling the compressor, the high pressure opening and closing valve, and the low pressure opening and closing valve.

Description

AIR CONDITIONER

The present invention relates to an air conditioner, and more particularly, to an air conditioner capable of pump down.

Generally, an air conditioner is disposed in a room such as a room, a living room, an office or a business store, and adjusts the temperature, humidity, cleanliness and airflow of the air to maintain a comfortable indoor environment.

The air conditioner can perform the air conditioning function by circulating the refrigerant according to a cooling cycle including a compressor, a condenser, an expansion valve, and an evaporator. That is, there is a refrigerant in the inside of the air conditioner, and there is a low possibility that the refrigerant will leak normally.

However, since the outdoor unit and the indoor unit of the air conditioner are separated from each other during the previous installation of the air conditioner, the refrigerant in the air conditioner may leak. To prevent this refrigerant leakage, a refrigerant pump down is performed.

The pump-down of the refrigerant means the operation of collecting the refrigerant in the outdoor unit, the indoor unit, and the piping in the outdoor unit or the indoor unit when the air conditioner is previously installed. In the case of a home air conditioner, it is common to collect the refrigerant toward the outdoor unit.

In the case of conventional air conditioners, in order to pump down the refrigerant, the user had to connect the pressure gauge to the service valve of the outdoor unit prior to the refrigerant pump down. More specifically, the user had to unload the high-pressure cap and the low-pressure cap, lock the low-pressure service valve, connect the pressure gauge to the low-pressure service valve, and perform the refrigerant pump down after opening the low-pressure service valve again.

Further, since the service valve must be manually opened and closed at the start and completion of the refrigerant pump-down, it is troublesome and the user may confuse the high-pressure service valve and the low-pressure service valve.

An object of the present invention is to provide an air conditioner in which a refrigerant pump-down can be automatically performed.

An air conditioner according to an embodiment of the present invention includes: a cooling cycle including a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger; An outdoor unit in which the compressor, the outdoor heat exchanger, and the expansion mechanism are disposed and includes a high-pressure service valve and a low-pressure service valve; An indoor unit in which the indoor heat exchanger is disposed; A high-pressure opening / closing valve disposed between the outdoor heat exchanger and the high-pressure service valve during the cooling cycle; A low pressure opening / closing valve disposed between the low pressure service valve and the compressor during the cooling cycle; A pressure sensor installed in the cooling cycle and measuring the pressure of the refrigerant; And a controller that receives the measured pressure of the pressure sensor and controls the compressor, the high-pressure on-off valve, and the low-pressure on-off valve.

The controller may close the high-pressure on-off valve and turn on the compressor in a pump-down mode.

The controller may close the low-pressure on-off valve and turn off the compressor when the pressure measured by the pressure sensor reaches a set pressure after the compressor is turned on in the pump-down mode.

The controller can operate the compressor at a maximum operating frequency in a pump down mode.

The high pressure opening / closing valve may be disposed between the expansion mechanism and the high pressure service valve during the cooling cycle.

The refrigeration cycle may further include an accumulator for preventing the liquid refrigerant from being sucked into the compressor, and the low pressure opening / closing valve may be disposed between the low pressure service valve and the accumulator during the cooling cycle.

According to a preferred embodiment of the present invention, refrigerant pump-down can be automatically performed by the high-pressure opening / closing valve and the low-pressure opening / closing valve, thereby improving convenience for the user.

In addition, there is no need for the user to lock the service valve directly, and there is an advantage that a malfunction due to the operation error of the user can be prevented.

Further, since the refrigerant pump-down is performed automatically, the refrigerant recovery amount can be constant. Thereby, it is possible to calculate the amount of refrigerant to be additionally enclosed, which is advantageous in that system damage, performance deterioration and cost increase due to lack of refrigerant, charging, etc. can be prevented.

1 is a schematic view of an air conditioner according to an embodiment of the present invention.
2 is a configuration diagram of an air conditioner according to an embodiment of the present invention.
FIG. 3 is a view showing the flow of the refrigerant in the pump down mode of the air conditioner shown in FIG. 2. FIG.
4 is a control block diagram of an air conditioner according to an embodiment of the present invention.
5 is a flowchart showing an example of a control method in the pump down mode of the air conditioner according to the embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

1 is a schematic view of an air conditioner according to an embodiment of the present invention.

Referring to FIG. 1, an air conditioner according to an embodiment of the present invention may include an outdoor unit O and an indoor unit I.

<Outdoor unit and indoor unit>

The types of the outdoor unit (O) and the indoor unit (I) are not limited. For example, the indoor unit I may be a wall-mounted type as shown in Fig. The indoor unit I may be a stand-alone type or a stand-type type which is provided on the floor surface.

The outdoor unit (O) can be disposed outdoors, and the indoor unit (I) can be disposed indoors.

The indoor unit I can perform indoor cooling or heating and the outdoor unit O can perform heat exchange with the outdoor air to satisfy the cooling / heating load due to the cooling or heating of the indoor unit I.

The housing 2 of the outdoor unit O may be provided with an air inlet 4 and an air outlet (not shown). The air inlet 4 may be formed on the front surface of the housing 2 and the air outlet may be formed on the rear surface of the housing 2.

The refrigerant can reciprocate between the outdoor unit (O) and the indoor unit (I). For this purpose, the outdoor unit (O) and the indoor unit (I) may be connected by a first connection passage (26) and a second connection passage (27). The directions of the refrigerant flowing into the first connection passage 26 and the second connection passage 27 may be opposite to each other.

The compressor 10, the outdoor heat exchanger 30 and the expansion mechanism 40, which will be described later, may be disposed in the outdoor unit (O). The indoor unit I may be provided with an indoor heat exchanger 50 to be described later.

<Service valve>

The outdoor unit (O) may be provided with service valves (60) and (70). More specifically, the outdoor unit O may be provided with a high-pressure service valve 60 to which the first connection passage 26 is connected and a low-pressure service valve 70 to which the second connection passage 27 is connected.

Each of the service valves 60 and 70 can be disposed so as to be accessible from the outside of the housing 2. More specifically, each service valve 60 (70) may be provided on the outer surface of the housing 2, or may be located on the incision 3 where a part of the housing 2 is cut. Thereby, the user can open or lock the respective service valve (60) (70) without detaching the housing (2).

Each service valve 60 (70) may be provided with a cap. The user can open or close the service valves 60 and 70 using a tool such as a wrench.

2 is a configuration diagram of an air conditioner according to an embodiment of the present invention.

Hereinafter, the configuration of the air conditioner according to one embodiment of the present invention will be described in detail with reference to FIG.

The air conditioner according to an embodiment of the present invention may include a cooling cycle 1 in which a refrigerant circulates, a high-pressure on-off valve 13, a low-pressure on-off valve 14 and a pressure sensor 16.

<Cooling Cycle>

The cooling cycle 1 may include a compressor 10, an outdoor heat exchanger 30, an expansion mechanism 40, and an indoor heat exchanger 50. The cooling cycle 1 may further include a four-way valve (20) and an accumulator (15).

The compressor 10, the four-way valve 20, the outdoor heat exchanger 30, the accumulator 15 and the expansion mechanism 40 may be disposed in the outdoor unit O. [ The indoor heat exchanger (50) may be disposed in the indoor unit (I).

&Lt; Connection relation between each configuration included in the cooling cycle >

The compressor 10 can be connected to the four-way valve 20 through the suction flow path 12 and the discharge flow path 11. [ The four-way valve 20 may be connected to the outdoor heat exchanger 30 through the first flow path 21. The outdoor heat exchanger (30) can be connected to the expansion mechanism (40) by the second flow path (22). The expansion mechanism (40) can be connected to the third heat exchanger (50) through the third flow path (23). The indoor heat exchanger (50) may be connected to the four-way valve (20) through a fourth flow path (24).

The third flow path 23 may include a first connection flow path 26 and a first internal flow path 25 and the fourth flow path 24 may include a second connection flow path 27 and a second internal flow path 28, . &Lt; / RTI &gt;

The first internal flow passage 25 may be a portion of the third flow passage 23 disposed inside the outdoor unit O. The first internal flow path 25 can connect the expansion mechanism 40 and the high-pressure service valve 60.

The first connection passage 26 may refer to a portion of the third flow passage 23 disposed outside the outdoor unit O. [ The first connection passage 26 can connect the high-pressure service valve 60 to the indoor heat exchanger 50. Therefore, a part of the first connection passage 26 can be disposed inside the indoor unit I.

And the second connection passage 27 may refer to a portion of the fourth flow path 24 disposed outside the outdoor unit O. [ The second connection passage 27 can connect the low-pressure service valve 70 and the indoor heat exchanger 50. Therefore, a part of the second connection passage 27 can be disposed inside the indoor unit I.

And the second internal flow passage 28 may refer to a portion of the fourth flow passage 24 disposed inside the outdoor unit O. [ The second internal flow passage 28 can connect the four-way valve 20 and the low-pressure service valve 70.

<Compressor>

The compressor (10) can compress the refrigerant. The compressor 10 is preferably an inverter compressor whose drive frequency is controlled.

The compressor (10) may be connected to the discharge passage (11) and the suction passage (12), respectively. The compressor 10 can suck and compress the refrigerant flowing into the suction passage 12 and can discharge the compressed refrigerant into the discharge passage 11. [

<Four-way valve>

The four-way valve 20 may be connected to the discharge passage 11 and the suction passage 12, respectively.

Further, the four-way valve 20 may be connected to the first flow path 21 and the fourth flow path 24, respectively. In more detail, the four-way valve 20 may be connected to the first flow path 21 and the second internal flow path 28, respectively.

In the cooling mode, the four-way valve 20 allows the discharge passage 11 to communicate with the outdoor heat exchanger 30, and allows the suction passage 12 and the indoor heat exchanger 50 to communicate with each other. More specifically, in the cooling mode, the four-way valve 20 can communicate the discharge passage 11 and the first passage 21, and can communicate the suction passage 12 and the fourth passage 24 with each other.

In the heating mode, the four-way valve 20 allows the discharge passage 11 and the indoor heat exchanger 50 to communicate with each other, and allows the suction passage 12 and the outdoor heat exchanger 30 to communicate with each other. More specifically, in the heating mode, the four-way valve 20 allows the discharge passage 11 and the fourth passage 24 to communicate with each other and allows the suction passage 12 and the first passage 21 to communicate with each other.

<Outdoor Heat Exchanger>

The outdoor heat exchanger (30) is capable of exchanging heat between the refrigerant and the outside air. More specifically, the outdoor heat exchanger (30) can exchange heat between the air blown by the outdoor fan (31) and the refrigerant passing through the outdoor heat exchanger (30). Accordingly, as the rotational speed of the outdoor fan 31 is increased, the heat exchange between the air and the refrigerant can be enhanced.

The outdoor fan (31) can be arranged to face the outdoor heat exchanger (30).

In the cooling mode, the outdoor heat exchanger 30 can act as a condenser. That is, the outdoor heat exchanger (30) can condense the refrigerant by heat exchange with the outside air. The faster the rotational speed of the outdoor fan 31, the more the condensation of the refrigerant can be activated.

In the heating mode, the outdoor heat exchanger 30 can function as an evaporator. That is, the outdoor heat exchanger 30 can evaporate the refrigerant by exchanging heat with the outside air. The faster the rotational speed of the outdoor fan 31, the more the evaporation of the refrigerant can be activated.

One side of the outdoor heat exchanger 30 may be connected to the four-way valve 20 through the first flow path 21 and the other side may be connected to the expansion mechanism 40 through the second flow path 22.

<Expansion mechanism>

The expansion mechanism (40) can expand the refrigerant passing through the expansion mechanism (40).

The expansion mechanism 40 is preferably an electric expansion valve (EEV), but is not limited thereto. The electronic expansion valve (EEV) is a kind of expansion valve whose opening can be adjusted.

The expansion mechanism (40) may be disposed in the outdoor unit (O). That is, the expansion mechanism (40) may be an outdoor expansion mechanism.

The expansion mechanism 40 may be connected to the outdoor heat exchanger 30 through the second flow path 22 and may be connected to the indoor heat exchanger 50 through the third flow path 23.

In the cooling mode, the refrigerant condensed in the outdoor heat exchanger (30) can flow to the expansion mechanism (40) along the second flow path (22). The refrigerant may expand through the expansion mechanism 40 and may flow to the indoor heat exchanger 50 along the third flow path 23.

In the heating mode, the refrigerant condensed in the indoor heat exchanger (50) can flow to the expansion mechanism (40) along the third flow path (23). The refrigerant can be expanded through the expansion mechanism (40) and flow to the outdoor heat exchanger (30) along the second flow path (22).

<High-pressure service valve>

On the other hand, a high-pressure service valve 60 may be installed in the third flow path 23. More specifically, the first internal flow path 25 can connect the high-pressure service valve 60 and the expansion mechanism 40, and the first connection flow path 26 is connected to the high-pressure service valve 60 and the indoor heat exchanger 50, .

The high-pressure service valve 60 can interrupt the flow of the refrigerant in the third flow path 23. The high-pressure service valve 60 may be a liquid-side service valve.

The high pressure service valve 60 is normally opened and the refrigerant can flow through the third flow path. However, when the user locks the high pressure service valve 60, the refrigerant flowing into the first internal flow path 25 flows into the first connection flow path 26).

<High-pressure opening / closing valve>

The high-pressure on-off valve 13 may be disposed between the outdoor heat exchanger 30 and the high-pressure service valve 60 during the cooling cycle 1. That is, the high-pressure on-off valve 13 may be disposed in the second flow path 22 or the first internal flow path 25.

Preferably, the high-pressure on-off valve 13 may be disposed between the expansion mechanism 40 and the high-pressure service valve 60 during the cooling cycle 1. That is, the high-pressure on-off valve 13 may be disposed in the first internal flow passage 25.

Compared to the case where the high-pressure on-off valve 13 is provided in the second flow path 22, the high-pressure on-off valve 13 is provided in the first internal flow path 25, .

<Indoor Heat Exchanger>

On the other hand, the indoor heat exchanger 50 can heat-exchange refrigerant and air. More specifically, the indoor heat exchanger (50) can exchange heat between the air blown by the indoor fan (51) and the refrigerant passing through the indoor heat exchanger (50). Accordingly, as the rotational speed of the indoor fan 51 is increased, the heat exchange between the air and the refrigerant can be enhanced.

In the cooling mode, the indoor heat exchanger 50 may function as an evaporator. That is, the indoor heat exchanger 50 can evaporate the refrigerant by exchanging heat with the outside air. The faster the rotation speed of the indoor fan 51, the more the evaporation of the refrigerant can be activated.

In the heating mode, the indoor heat exchanger 50 can act as a condenser. That is, the indoor heat exchanger (50) can condense the refrigerant by heat exchange with the outside air. The faster the rotational speed of the indoor fan 51, the more condensed the refrigerant can be.

One side of the indoor heat exchanger 50 may be connected to the expansion mechanism 40 through the third flow path 23 and the other side may be connected to the fourth flow path 22 and the four-

<Low pressure service valve>

A low-pressure service valve 70 may be installed in the fourth flow path 24. The second internal flow passage 28 can connect the low pressure service valve 70 and the four-way valve 20 and the second connection flow passage 27 can connect the low-pressure service valve 70 and the indoor heat exchanger 50, .

The low-pressure service valve 70 is capable of interrupting the refrigerant flow of the fourth flow path 24. The low pressure service valve 70 may be an engine side service valve.

The low pressure service valve 70 is opened to allow the refrigerant to flow through the fourth flow path 24, but when the user locks the low pressure service valve 70, the refrigerant flowing into the second connection flow path 27 flows into the second It can not flow into the inner flow path 28.

<Low-pressure opening / closing valve>

The low-pressure on-off valve 14 may be disposed between the low-pressure service valve 70 and the compressor 10 during the cooling cycle 1. That is, the low-pressure on-off valve 14 may be disposed in the second internal flow passage 28 or the suction flow passage 12.

Preferably, the low-pressure on-off valve 14 may be disposed between the low-pressure service valve 70 and the accumulator 15 during the cooling cycle 1.

In the pump-down mode, the refrigerant can be recovered into the outdoor unit O by being accommodated between the high-pressure opening / closing valve 13 and the low-pressure opening / closing valve 14 during the cooling cycle. This will be described in detail later.

<Accumulator>

The accumulator 15 may be disposed in the suction passage 12.

The accumulator 15 can prevent the liquid refrigerant from being sucked into the compressor 10. More specifically, the accumulator 15 accommodates the liquid refrigerant in the introduced refrigerant, and can discharge only the gaseous refrigerant. As a result, only the refrigerant in the gaseous state can be sucked into the compressor (10).

<Pressure sensor>

The pressure sensor 16 may be connected to the cooling cycle 1. The position where the pressure sensor 16 is connected during the cooling cycle 1 may be varied as required. The pressure sensor 16 may be connected to a portion of the refrigeration cycle 1 other than the space between the outdoor heat exchanger 30 and the high-pressure on-off valve 13.

For example, the pressure sensor 16 may be installed in the suction passage 16 or may be provided outside the outdoor unit (O).

The pressure sensor 16 may measure the pressure of the refrigerant flowing along the refrigeration cycle 1 and may transmit the measured pressure value to the controller 90 to be described later.

As the pump-down progresses, the pressure of the refrigerant measured by the pressure sensor 16 may be lowered, and the pump-down mode may be terminated when the pressure measured by the pressure sensor 16 reaches the set pressure. This will be described in detail later.

FIG. 3 is a view showing the flow of the refrigerant in the pump down mode of the air conditioner shown in FIG. 2. FIG.

<Pump down mode>

Hereinafter, the operation of the air conditioner in the pump down mode according to the embodiment of the present invention will be described with reference to FIG.

Prior to entering the pump down mode, the refrigerant may be located in the interior of the configurations that make up the cooling cycle and in the interior of the flow paths connecting the respective configurations. The pump-down mode is a mode for collecting the refrigerant into the outdoor unit (O).

The pump-down mode is basically similar to the cooling mode, except that the high-pressure on-off valve 13 and the low-pressure on-off valve 14 are sequentially closed. This will be described in detail below.

In the pump down mode, the compressor 10 can compress the sucked refrigerant in a state in which the high-pressure on-off valve 13 is closed. At this time, the low-pressure on-off valve 14 may be in an open state.

Further, in the pump down mode, the four-way valve 20 can communicate the suction passage 12 and the indoor heat exchanger 50 with each other. Therefore, the refrigerant evaporated in the indoor heat exchanger (50) can be sucked into the compressor (10) through the fourth flow path (24) and the suction flow path (12).

The suction force of the compressor 10 allows the refrigerant between the high-pressure on-off valve 13 and the compressor 10 to flow in the direction of the compressor 10 along the flow direction of the refrigerant. That is, the refrigerant in the suction flow path 12, the fourth flow path 24, the indoor heat exchanger 50, and the third flow path 23 can be sucked into the compressor 10.

The suction force of the compressor 10 may not reach the refrigerant located on the opposite side of the high-pressure on-off valve 13 with respect to the high-pressure service valve 60 because the high-pressure on-off valve 13 is closed.

In the pump down mode, the indoor heat exchanger 50 can act as an evaporator. Therefore, the refrigerant flowing into the indoor heat exchanger (50) can be evaporated through the indoor heat exchanger (50).

In the pump-down mode, the indoor fan 51 can rotate at the maximum speed. Therefore, evaporation of the refrigerant in the indoor heat exchanger (50) can be actively performed.

The refrigerant evaporated in the indoor heat exchanger (50) can flow into the suction flow path (12) through the fourth flow path (24). The refrigerant that has flowed into the suction passage 12 may be introduced into the accumulator 15. The accumulator 15 stores the liquid refrigerant and can take out the gaseous refrigerant. The gaseous refrigerant can be sucked into the compressor 10 and compressed.

Since a certain amount of refrigerant is stored in the accumulator 15, there is an advantage that the amount of recovered refrigerant increases at the time of pump down.

On the other hand, the compressor 10 can compress the sucked refrigerant and discharge it into the discharge passage 11. [

In the pump down mode, the four-way valve 20 can communicate the discharge passage 11 and the outdoor heat exchanger 30. Therefore, the refrigerant discharged to the discharge flow path 11 can flow to the outdoor heat exchanger 30 along the first flow path 21.

In the pump down mode, the outdoor heat exchanger 30 can act as a condenser. Therefore, the refrigerant passes through the outdoor heat exchanger 30 and can be condensed.

In the pump-down mode, the outdoor fan 31 can rotate at the maximum speed. Therefore, the condensation of the refrigerant in the outdoor heat exchanger (30) can be actively performed.

When the high-pressure on-off valve 13 is installed in the first internal flow passage 25, the refrigerant condensed in the outdoor heat exchanger 30 can flow through the expansion mechanism 40 to the high-pressure on-off valve 13. At this time, since the high-pressure on-off valve 13 is in a closed state, the refrigerant may not pass through the high-pressure on-off valve 13. When the high-pressure on-off valve 13 is installed in the second flow path 22, the refrigerant condensed in the outdoor heat exchanger 30 may be blocked by the high-pressure on-off valve 13 and may not reach the expansion mechanism 40.

The refrigerant can not circulate along the cooling cycle 1 and can be collected in a previous portion of the high pressure opening and closing valve 13 along the flow direction of the refrigerant.

Since most of the refrigerant is collected in the first flow path 21, the outdoor heat exchanger 30 and the second flow path 22, the refrigerant in the other part can be reduced, and accordingly, the pressure value measured by the pressure sensor 16 Can be lowered. When the measured pressure of the pressure sensor 16 becomes sufficiently low and reaches the set pressure, the low-pressure on-off valve 14 is closed and the compressor 10 can be turned off.

When the compressor 10 is turned off, the suction force of the compressor 10 is not applied, so that the refrigerant located in the suction passage 12 can flow backward. At this time, since the low-pressure on-off valve 14 is in the closed state, the reverse flow of the refrigerant can be prevented.

Consequently, depending on the pump-down mode, the refrigerant that has been spread throughout the cooling cycle may collect in the outdoor unit O and be recovered. More specifically, when the pump-down mode is completed, the recovered refrigerant can be trapped between the high-pressure on-off valve 13 and the low-pressure on-off valve 14.

Thereby, even if the user does not operate the service valves 60 and 70 separately, the pump down can be performed automatically, and there is an advantage that the amount of the refrigerant can always be recovered to a certain level or more.

The user can then lock each service valve 60 (70) in turn. At this time, the order of locking the high-pressure service valve 60 and the low-pressure service valve 70 is irrelevant. Therefore, confusion of the user can be prevented. Further, even if the user can not distinguish between the high-pressure service valve 60 and the low-pressure service valve 70, there is no malfunction and the pump-down can be performed stably.

Thereafter, the user can slightly loosen the piping connection flare to purge and separate the residual refrigerant. Thereby, the refrigerant can be stably recovered and the air conditioner can be transferred.

4 is a control block diagram of an air conditioner according to an embodiment of the present invention.

Referring to FIG. 4, an air conditioner according to an embodiment of the present invention may include a controller 90.

<Controller>

The controller 90 may be provided in the indoor unit I and / or the outdoor unit O. [

The controller 90 may include an input unit provided with a user interface. The user can directly input a command to the user interface or input a command to the input unit through a remote controller or the like.

The operation mode of the air conditioner can be determined by the user's command. For example, the user can select one of a heating mode, a cooling mode, and a pump-down mode. Also, the user can input desired temperature, air volume, wind direction, and the like.

The controller 90 may include a communication unit. The communication unit may be capable of wired / wireless communication with a separate terminal or a central controller.

The controller 90 can receive the measured pressure from the pressure sensor 14.

The controller 90 can control the compressor 10, the high-pressure on-off valve 13, and the low-pressure on-off valve 14. In addition, the controller 90 can control the outdoor fan 31 and the indoor fan 51, and the controller 90 can be configured to further control the additional configuration as needed.

The controller 90 can turn the compressor 10 on and off and control the operation frequency of the compressor 10. [

The controller 90 can turn on and off the outdoor fan 31 and the indoor fan 51, respectively. In addition, the controller 90 can control the rotational speeds of the outdoor fan 31 and the indoor fan 51. [

The controller 90 can control the high-pressure on-off valve 13 and the low-pressure on-off valve 14 on and off.

FIG. 5 is a flowchart illustrating an example of a control method in a pump-down mode of an air conditioner according to an embodiment of the present invention.

<Detailed control in pump-down mode>

The controller 90 can start the pump-down mode of the air conditioner according to a user's input or the like.

In the pump down mode, the controller 90 controls the four-way valve 20 to communicate the discharge passage 11 of the compressor 10 with the outdoor heat exchanger 30 (S1). The controller 90 may turn on the compressor 10 and close the high-pressure on-off valve 13 after controlling the four-way valve 20 (S2). Further, the controller 90 can keep the low-pressure on-off valve 14 open.

At this time, the controller 90 can operate the compressor 10 at the maximum operating frequency. This has the advantage that the flow rate of the refrigerant is increased and the pump down can be performed quickly.

The refrigerant discharged from the compressor 10 flows to the high pressure opening / closing valve 13 and does not pass through the high pressure opening / closing valve 13, so that the refrigerant can be collected before the high pressure opening / closing valve 13 with respect to the flow direction of the refrigerant. Further, the refrigerant located after the high-pressure on-off valve 13 with respect to the flow direction of the refrigerant can be sucked into the compressor through the suction flow path 12 of the compressor 10. Thereby, the refrigerant in the indoor unit (I) can be recovered into the outdoor unit (O).

The controller 90 may determine whether the measured pressure of the pressure sensor 16 has reached a predetermined set pressure (S3).

For example, when the pressure sensor 16 is connected to the suction passage 12, the refrigerant sucked into the compressor 1 through the suction passage 12 may gradually decrease as the pump down proceeds, and the pressure sensor 16 ) Can be gradually lowered. The set pressure may be zero, which means that all of the refrigerant is recovered and the pressure in the suction passage 12 is equal to the atmospheric pressure.

The controller 90 closes the low-pressure on-off valve 14 and turns off the compressor 10 because the refrigerant has sufficiently been recovered when the pressure value measured by the pressure sensor 16 reaches the set pressure (S4) . Thereby, the pump-down mode of the air conditioner can be ended.

As described above, even if the compressor 10 is turned off, the recovered refrigerant may be trapped between the high-pressure on-off valve 13 and the low-pressure on-off valve 14 and may not leak. Thereby, the pump-down can be completed.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments.

The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

10: compressor 13: high-pressure opening / closing valve
14: Low-pressure opening / closing valve 15: Accumulator
16: Pressure sensor 20: Four-way valve
30: outdoor heat exchanger 40: expansion device
50: indoor heat exchanger 60: high-pressure service valve
70: Low pressure service valve 90: Controller
I: Indoor unit O: Outdoor unit

Claims (6)

A cooling cycle including a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger;
An outdoor unit in which the compressor, the outdoor heat exchanger, and the expansion mechanism are disposed and includes a high-pressure service valve and a low-pressure service valve;
An indoor unit in which the indoor heat exchanger is disposed;
A high-pressure opening / closing valve disposed between the outdoor heat exchanger and the high-pressure service valve during the cooling cycle;
A low pressure opening / closing valve disposed between the low pressure service valve and the compressor during the cooling cycle;
A pressure sensor installed in the cooling cycle and measuring the pressure of the refrigerant; And
And a controller that receives the measured pressure of the pressure sensor and controls the compressor, the high-pressure on-off valve, and the low-pressure on-off valve. The method according to claim 1,
The controller comprising:
And closes the high-pressure on-off valve and turns on the compressor in a pump-down mode. 3. The method of claim 2,
The controller comprising:
And closes the low-pressure on-off valve and turns off the compressor when the pressure measured by the pressure sensor reaches the set pressure after the compressor is turned on in the pump-down mode. The method according to claim 1,
The controller comprising:
Wherein the compressor is operated at a maximum operating frequency in a pump-down mode. The method according to claim 1,
Wherein the high-pressure on-off valve is disposed between the expansion mechanism and the high-pressure service valve during the cooling cycle. The method according to claim 1,
The cooling cycle includes:
Further comprising an accumulator for preventing the liquid refrigerant from being sucked into the compressor,
And the low-pressure on-off valve is disposed between the low-pressure service valve and the accumulator during the cooling cycle.

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