KR101712213B1 - Multi type air conditiner and method of controlling the same - Google Patents

Abstract

The present invention relates to a multi-type air conditioner and a control method thereof. A multi-type air conditioner according to one aspect includes: a plurality of indoor units each including an indoor heat exchanger; And a plurality of outdoor units connected to the plurality of indoor units and each having an outdoor heat exchanger. When the defrosting operation condition is satisfied during the heating operation, the outdoor units sequentially perform the defrost operation.

Description

[0001] Multi-type air conditioner and control method thereof [0002]

The present invention relates to a multi-type air conditioner and a control method thereof.

Background Art [0002] Generally, an air conditioner is a device for cooling and heating indoor air or purifying air using a refrigerant cycle including a compressor, a condenser, an expansion device, and an evaporator to create a more comfortable indoor environment for a user.

The air conditioner includes an air conditioner in which one indoor unit is connected to one outdoor unit, and a multi-type air conditioner in which a plurality of indoor units are connected to at least one outdoor unit,

In the case of a multi-type air conditioner, a plurality of indoor units may include a plurality of outdoor units. Each of the outdoor units includes an outdoor heat exchanger. Each of the outdoor heat exchangers is divided into an upper heat exchanger and a lower heat exchanger based on the refrigerant flow, so that the refrigerant flows independently to the upper heat exchanger and the lower heat exchanger.

In the conventional multi-type air conditioner, when the heating operation is continued, the defrosting operation is performed by conception on the outdoor heat exchanger. In the defrosting operation, defrosting of the upper heat exchanger is performed first of the plurality of outdoor heat exchangers, and defrosting of the lower heat exchanger is performed when defrosting of the upper heat exchanger is completed. During the defrosting operation, the high-temperature and high-pressure refrigerant discharged from the compression unit is bypassed and flows to the heat exchange unit where the defrosting is performed.

In the conventional multi-type air conditioner, since some of the heat exchanging units (50% of the total outdoor heat exchangers) are defrosted in each of the outdoor heat exchangers of all the outdoor units, some of the remaining heat exchanging units (50% And the heating efficiency is lowered.

Further, since defrosting of the lower heat exchanger is performed after the defrosting of the upper heat exchanger is completed, there is a problem that the defrosting is not smoothly performed at the boundary between the upper heat exchanger and the lower heat exchanger.

In addition, since the refrigerant bypassed in the compression unit during the defrosting operation flows to the outdoor heat exchanger, there is a problem that the amount of the refrigerant flowing to the outdoor heat exchanger is small and the defrosting takes a long time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-type air conditioner and a control method thereof, in which defrosting can be performed while minimizing deterioration of heating performance.

It is also an object of the present invention to provide a multi-type air conditioner capable of quickly defrosting the outdoor heat exchanger and effectively removing the property in the outdoor heat exchanger and a control method thereof.

A multi-type air conditioner according to one aspect includes: a plurality of indoor units each including an indoor heat exchanger; And a plurality of outdoor units connected to the plurality of indoor units and each having an outdoor heat exchanger. When the defrosting operation condition is satisfied during the heating operation, the outdoor units sequentially perform the defrost operation.

A method of controlling a multi-type air conditioner according to another aspect of the present invention includes: controlling a plurality of outdoor units in a heating operation mode of a multi-type air conditioner including a plurality of indoor units and a plurality of outdoor units; Determining whether the defrosting operation condition is satisfied during the heating operation; And when a defrosting operation condition is satisfied, a plurality of outdoor units sequentially perform a defrost operation.

According to the present invention, even when the air conditioner is defrosting operation, the indoor unit performs the heating operation, so that continuous heating of the room can be performed and an indoor comfort can be maintained.

In addition, since defrosting is performed on all of the plurality of heat exchangers of the outdoor heat exchanger, the performance of the outdoor heat exchanger as a whole can be effectively removed.

1 is a configuration diagram of a multi-type air conditioner according to an embodiment of the present invention;
2 is a view showing a refrigerant cycle of the multi-type air conditioner.
FIG. 3 is a view showing a refrigerant flow during a cooling operation of the multi-type air conditioner according to the present invention. FIG.
4 is a view for explaining a control method of the multi-type air conditioner of the present invention.
5 to 8 are schematic views showing that a plurality of outdoor units are sequentially defrosted.
9 and 10 are views showing a refrigerant flow when a specific outdoor unit is defrosted. FIG. 9 shows a refrigerant flow when the fourth indoor unit is defrosted, and FIG. 10 shows a case where the first indoor unit is defrosted Lt; / RTI > is shown.

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

FIG. 1 is a configuration diagram of a multi-type air conditioner according to an embodiment of the present invention, and FIG. 2 is a configuration diagram showing a refrigerant cycle of the multi-type air conditioner. FIG. 2 shows a refrigerant flow when the multi-type air conditioner is operated in a heating mode.

1 and 2, a multi-type air conditioner according to an embodiment of the present invention includes an outdoor unit unit 1, an indoor unit unit 2 connected to the outdoor unit unit 1 by a distributor 3, . The outdoor unit unit (1) includes a plurality of outdoor units (11, 12, 13, 14). The indoor unit (2) includes a plurality of indoor units (21, 22, 23, 24). In this specification, four indoor units are connected to four outdoor units for convenience of explanation, but the number of indoor units and the number of outdoor units are not limited in the present specification. That is, two or more indoor units may be connected to two or more outdoor units. At this time, the number of the indoor units may be larger than the number of the outdoor units.

The outdoor unit unit (1) includes a first outdoor unit (11), a second outdoor unit (12), a third indoor unit, and a fourth indoor unit (14). Since the first outdoor unit 11 and the second outdoor unit 15 have the same configuration, only the configuration of the first outdoor unit 11 will be described below. The same reference numerals used in the description of the first outdoor unit 11 will be applied to the configurations of the second outdoor unit to the fourth outdoor unit.

Each of the outdoor units 11, 12, 13 and 14 includes a compression unit 110 for compressing refrigerant and outdoor heat exchangers 130, 200, 210 and 220 for exchanging heat between outdoor air and refrigerant. The compression unit 110 may include a plurality of compressors 111, 112, and 113. Some of the compressors 111, 112 and 113 are inverter compressors 111 whose capacity is variable and others may be constant speed compressors 112 and 113. The plurality of compressors 111, 112, and 113 may be arranged in parallel. Some or all of the plurality of compressors may be operated depending on the capacity of the indoor unit. Alternatively, each of the outdoor units 11, 12, 13, and 14 may include a single compressor.

The discharge side piping of each of the compressors 111, 112, and 113 includes an individual piping 118 and a joint piping 119. That is, the individual piping 118 of each of the compressors 111, 112, and 113 is connected to the joint piping 119. Each of the individual pipes 118 is provided with oil separators 114, 115 and 116 for separating oil from the refrigerant, a temperature sensor 126 for sensing the temperature of the compressed refrigerant, A pressure sensor 127 may be provided.

The joint pipe 119 is connected to a plurality of four-way valves 121 and 122 for switching the refrigerant flow path. The plurality of four-way valves 121 and 122 include a first four-way valve 121 and a second four-way valve 122. The first four-way valve 121 and the second four-way valve 122 are arranged in parallel.

The four-way valves 121 and 122 are connected to the outdoor heat exchanger 130 by first connection pipes 123 and 124, respectively. The first connection pipe includes a first heat exchange unit connection pipe 123 and a second heat exchange unit connection pipe 124.

Each of the outdoor heat exchangers 130, 200, 210 and 220 includes a first heat exchanger 131 and a second heat exchanger 132. The first heat exchanging unit 131 and the second heat exchanging unit 132 may be separate heat exchangers or heat exchangers that are classified based on the refrigerant flow in a single outdoor heat exchanger. The first four-way valve 121 is connected to the first heat exchange unit 131 by the first heat exchange unit connection pipe 123 and the second four-way valve 122 is connected to the second heat exchange unit connection pipe 124 to the second heat exchanging part 132. [ The first heat exchanging part 131 and the second heat exchanging part 132 are arranged in parallel. For example, the first heat exchanging unit 131 and the second heat exchanging unit 132 may be disposed horizontally or vertically. Accordingly, the refrigerant can flow independently to the first heat exchanging part 131 and the second heat exchanging part 132. [ The refrigerant may flow to each of the first heat exchanging unit 131 and the second heat exchanging unit 132, or may flow to any heat exchanger. The flow direction of the refrigerant in the first heat exchanging part 131 and the second heat exchanging part 132 may be the same or opposite. That is, the first heat exchanging unit 131 and the second heat exchanging unit 132 can operate independently. That is, each of the heat exchangers may independently function as a condenser or an evaporator.

In this embodiment, the outdoor heat exchanger is divided into a plurality of heat exchangers and a plurality of four-way valves are provided. Alternatively, a single outdoor heat exchanger may be provided and a single four-way valve may be connected to the outdoor heat exchanger .

The refrigerant of the outdoor heat exchanger may be heat-exchanged with outdoor air blown by the outdoor fan motor assembly (including the outdoor fan and the fan motor) (140). One or more outdoor fan motor assemblies may be provided. In FIG. 1, for example, two outdoor fan motor assemblies are shown.

The four-way valves 121 and 122 may be connected to the accumulator 135 by a second connection pipe 134. The four-way valves 121 and 122 may be connected to the closing pipes 121a and 122a.

The outdoor units (11, 12, 13, 14) further include an outdoor expansion mechanism (150). When the refrigerant passing through the outdoor heat exchanger (130, 200, 210, 220) passes, the outdoor expansion mechanism (150) expands the outdoor heat exchanger (130, 200, 210, 220) When the refrigerant passes through it, it expands the refrigerant.

The outdoor expansion mechanism 150 includes a first outdoor expansion valve 151 corresponding to the first heat exchange unit 131 and a second outdoor expansion valve 152 corresponding to the second heat exchange unit 132 do. The first outdoor expansion valve (151) and the second outdoor expansion valve (152) are arranged in parallel. That is, the refrigerant expanded by the first outdoor expansion valve 151 flows to the first heat exchange unit 131, and the refrigerant expanded by the second outdoor expansion valve 152 flows into the second heat exchange unit 132 < / RTI >

Each of the outdoor expansion valves 151 and 152 may be an electronic expansion valve (EEV), for example.

The outdoor units 11, 12, 13 and 14 are connected to the distributor 3 by a low-pressure pipe 311 and a low-pressure pipe 312. The outdoor units 11, 12, 13 and 14 are connected to the distributor 3 by a high-pressure pipe 321 and a high-pressure connecting pipe 322. The outdoor units 11, 12, 13 and 14 are connected to the distributor 3 by a liquid pipe 331 and a liquid pipe 332.

The low pressure orifices 311 of the outdoor units 11, 12, 13 and 14 are connected to the second connection pipe 134 and the low pressure connection pipe 312. The high-pressure orifices 321 of the outdoor units 11 and 15 are connected to the joint pipe 119 and the high-pressure connection pipe 322, which are upstream of the four-way valves 121 and 122. The liquid pipe 331 of each of the outdoor units 11, 12, 13 and 14 is connected to the outdoor expansion mechanism 150 and the liquid connection pipe 332.

The distributor 3 is connected to the plurality of indoor units 21, 22, 23, and 24 and the outdoor unit 1 to control the refrigerant flow. The distributor 3 is connected to each of the indoor units 21, 22, 23, and 24 by an indoor unit 313 and an indoor unit 333.

The distributor 3 includes a low pressure gas pipe 31, a high pressure gas pipe 32, a liquid pipe 33, a low pressure valve 314 and a high pressure valve 324. The low pressure connection pipe 312 and the indoor pipe 313 are connected to the low pressure gas pipe 31 and the liquid pipe 333 and the liquid connection pipe 332 are connected to the liquid pipe 33. The high pressure connection pipe 322 and the branch pipe 323 connected to the indoor liquid pipe 333 are connected to the high pressure gas pipe 32. The first valve 315 and the second valve 316 are provided in the low pressure engine 311 of each of the outdoor units 11, 12, 13 and 14. The second valve 325 and 326 are provided in the high pressure engine 321, The liquid pipe 331 is provided with third valves 335 and 336.

The low pressure valve 314 is provided in the indoor engine 313 and the high pressure valve 324 is connected to the branch pipe 323. In the present invention, the low-pressure valve 314 and the high-pressure valve 324 may be an electronic expansion valve (EEV) whose opening degree is adjusted linearly or stepwise.

The indoor units 21, 22, 23 and 24 are connected to the indoor heat exchangers 211, 221, 231 and 241, the indoor fans 212, 222, 232 and 242, 233 and 243, respectively. The indoor expansion mechanisms 213, 223, 233, and 243 may be, for example, an electronic expansion valve (EEV).

Hereinafter, the operation of the multi-type air conditioner of the present invention will be described.

Referring to FIG. 2, when the multi-type air conditioner is operated in a heating mode, that is, when one or more indoor units are heated (in FIG. 1, four indoor units are heated) 12, 13, and 14 are operated. At this time, the low-pressure valve 314 is closed and the high-pressure valve 324 is opened. The first valves 315 and 316 provided in the low-pressure pipe 311 may be closed.

The high-temperature and high-pressure refrigerant discharged from each compression unit 110 flows to the high-pressure gas pipe 32 along the high-pressure pipe 321 by regulating the flow path of the four-way valves 121 and 122. At this time, since the joint pipe 119 is connected to the closing pipes 121a and 122a by the four-way valves 121 and 122, it can no longer flow at the ends of the closing pipes 121a and 122a, And flows along the engine 321.

The refrigerant flowing into the high pressure gas pipe 32 is sent to the respective indoor heat exchangers 211, 221, 231, and 241 through the respective branch pipes 323 and the indoor engine 313. Next, the refrigerant is condensed in the indoor heat exchangers 211, 221, 231, and 241 and then passes through the indoor expansion mechanisms 213, 223, 233, and 243 without expansion, And flows into the liquid pipe 33. The refrigerant flowing into the liquid pipe 33 flows along the liquid connecting pipe 332 and the liquid pipe 331 and flows into the outdoor heat exchanger 130, 200, 210, 220). Then, the refrigerant is evaporated while passing through the outdoor heat exchangers 130, 200, 210 and 220, and then flows into the accumulator 135 through the four-way valves 121 and 122. The gaseous refrigerant in the refrigerant flowing into the accumulator flows into the compression unit 110.

When the heating operation is continued as described above, defrosting occurs in the outdoor heat exchangers (130, 200, 210, 220), and a defrosting operation for removing the fumes is required. The defrosting operation will be described later.

FIG. 3 is a view showing a refrigerant flow during a cooling operation of the multi-type air conditioner according to the present invention.

Referring to Fig. 3, the cooling operation will be described.

In the case where the multi-type air conditioner is in the cooling mode, that is, when one or more indoor units are in the cooling mode (in the example shown in FIG. 2, four indoor units are cooling- The unit works. At this time, the high-pressure valve 324 is closed and the low-pressure valve 314 is opened. The second valves 325 and 326 provided in the high-pressure pipe 321 may be closed.

The high-temperature and high-pressure refrigerant discharged to each of the compression units 110 is supplied to the outdoor heat exchangers 130, 200, 210 (or 210, 210) along the first connection pipes 123, , 220). The refrigerant then passes through the outdoor heat exchanger (130, 200, 210, 220) and is condensed and then passes through the outdoor expansion device (150) without expansion. The refrigerant passing through the outdoor expansion mechanism (150) flows to the liquid pipe (33) along the liquid pipe (331) and the liquid pipe (332). The refrigerant which has flowed into the liquid pipe 33 flows through the respective indoor liquid pipes 333 and is expanded while flowing through the indoor expansion mechanisms 213, 223, 233 and 243. The expanded refrigerant is evaporated while passing through the respective indoor heat exchangers (211, 221, 231, 241). Then, the evaporated refrigerant flows to the low-pressure gas pipe 31 along the indoor engine 313. The refrigerant flowing into the low pressure gas pipe 31 flows to the second connection pipe 134 along the low pressure connection pipe 312 and the low pressure pipe 311. The refrigerant then flows into the accumulator 135. The gaseous refrigerant in the refrigerant flowing into the accumulator 135 flows into the compression unit 110.

FIG. 4 is a view for explaining a control method of the multi-type air conditioner according to the present invention, FIGS. 5 to 8 are views for explaining how a plurality of outdoor units are sequentially defrosted, FIGS. Fig. 5 is a view showing the flow of refrigerant when the defrosting operation is performed. Fig. 9 shows the refrigerant flow when the fourth indoor unit is defrosted, and Fig. 10 shows the refrigerant flow when the first indoor unit is defrosted.

Referring to FIGS. 4 to 10, the multi-type air conditioner is heated by the heating operation command (S1). During the heating operation of the multi-type air conditioner, a control unit (not shown) determines whether the defrosting operation condition is satisfied (S2).

In this specification, whether or not the defrosting operation condition is satisfied can be determined by comparing the outlet pipe temperature of the outdoor heat exchanger with the outdoor temperature, for example. At this time, since the plurality of outdoor units operate simultaneously, the time when the defrosting operation condition is satisfied in each of the plurality of outdoor units will be similar. However, when the defrosting operation condition of each outdoor unit is satisfied, the defrosting operation condition of all the outdoor units is satisfied, or when the defrosting operation condition of the outdoor unit satisfying the defrosting operation condition is satisfied It may be the case that the number reaches the reference number.

In this specification, the determination as to whether or not the defrosting operation condition is satisfied can be performed by various methods other than the described method, and there is no limitation on the method for determining whether the defrosting operation condition is satisfied.

As a result of the determination in step S2, if the defrosting operation condition is satisfied, the multi-type air conditioner operates in the defrost operation mode. Specifically, the plurality of outdoor units can be defrosted sequentially (S3). That is, any one of the outdoor units performs the defrosting operation and the remaining outdoor units performs the heating operation, and when the defrosting operation of any of the outdoor units is completed, the outdoor units in the next order are defrosted.

In this embodiment, the defrosting operation order can be determined by the capacity (heat exchange capacity) of the outdoor unit. That is, when all or some of the outdoor units have different capacities, the defrost operation is performed from the outdoor unit having a small capacity. If all or some of the outdoor units have the same capacity, the defrosting operation is performed in a predetermined order. That is, when the product is produced, the defrosting order of the outdoor units is set in advance, and when the defrosting operation conditions are satisfied, the outdoor units can be defrosted in the set order.

In this embodiment, it is assumed that the defrosting sequence is performed in the order of the fourth indoor unit, the third indoor unit, the second indoor unit, and the first indoor unit.

5 and 9, when the fourth outdoor unit 14 is defrosted, the outdoor heat exchanger 220 of the fourth outdoor unit 14 is switched by the four-way valve of the fourth outdoor unit 14, Is switched to the condenser state. That is, as shown in FIG. 5, the plurality of heat exchangers of the fourth outdoor unit 14 are switched to the condenser state. Of course, the outdoor heat exchangers 130, 200 and 210 of the first to third indoor units 11, 12 and 13 are maintained in an evaporator state and the indoor heat exchangers 130, The condensers 211, 221, 231, and 241 are maintained in the condenser state.

Then, the high-temperature, high-pressure refrigerant discharged from the compression unit of the fourth outdoor unit (14) flows to the outdoor heat exchanger through the four-way valve. The defrosting of the outdoor heat exchanger is performed during the passage of the high-temperature and high-pressure refrigerant through the outdoor heat exchanger.

The refrigerant that has passed through the outdoor heat exchanger of the fourth outdoor unit 14 flows along the liquid pipe of the fourth outdoor unit 14 and then flows into the liquid pipe of the first outdoor unit 11 together with the refrigerant discharged from the liquid pipe 33, Respectively. During the defrosting operation of the fourth outdoor unit 14, the second valve 326 provided in the high-pressure unit of the fourth outdoor unit 14 may be closed. During the defrosting operation of the fourth outdoor unit 14, the outdoor fan motor assembly (outdoor fan and fan motor) provided in the fourth outdoor unit 14 stops. The opening degree of the outdoor expansion mechanism of the fourth outdoor unit (14) may be larger than the opening degree of the previous state (the opening degree when the outdoor heat exchanger of the second outdoor unit is the evaporator).

A part of the refrigerant evaporated while passing through the outdoor heat exchanger in the first to third outdoor units 11, 12 and 13 is supplied to the accumulators 135 of the first to third outdoor units 11, 12, And the other part flows to the accumulator of the fourth outdoor unit 14 along each of the low-pressure orifices.

On the other hand, when the defrosting operation of the fourth outdoor unit 14 is completed, the outdoor heat exchanger 220 of the fourth outdoor unit 14 is switched to the evaporator state by the flow control of the four-way valve.

Then, the defrosting operation of the third outdoor unit 13 is started as shown in Fig. When the defrosting operation of the third outdoor unit 13 is performed, the outdoor heat exchanger 210 of the third outdoor unit 13 acts as a condenser and the outdoor heat exchanger of the remaining outdoor unit acts as an evaporator. When the defrosting operation of the third outdoor unit 13 is completed, the defrosting operation of the second outdoor unit 12 is started as shown in FIG. When the defrosting operation of the second outdoor unit 12 is performed, the outdoor heat exchanger 210 of the second outdoor unit 12 acts as a condenser and the outdoor heat exchanger of the remaining outdoor unit acts as an evaporator. When the defrosting operation of the second outdoor unit is completed, the defrosting operation of the first outdoor unit 11 is finally started.

Referring to FIG. 10, when the first outdoor unit 11 is defrosted, the outdoor heat exchanger 130 of the first outdoor unit 11 is switched to the condenser state . Of course, the outdoor heat exchangers of the second to fourth outdoor units 12, 13 and 14 are maintained in the evaporator state and the indoor heat exchangers 211, 221, 231 and 241 of the indoor units 21, 22, ) Is maintained in the condenser state.

Then, the high-temperature, high-pressure refrigerant discharged from the compression unit of the first outdoor unit (11) flows to the outdoor heat exchanger (130) through the four-way valve. The defrosting of the outdoor heat exchanger (130) is performed during the passage of the high temperature and high pressure refrigerant through the outdoor heat exchanger (130).

The refrigerant that has passed through the outdoor heat exchanger 130 of the first outdoor unit 11 flows along the liquid pipe of the first outdoor unit 11 and then the refrigerant discharged from the liquid pipe 33, And flows into the liquid pipes of the four outdoor units (12, 13, 14). During the defrosting operation of the first outdoor unit 11, the second valve 325 provided in the high-pressure unit of the first outdoor unit 11 may be closed. During the defrosting operation of the first outdoor unit (11), the outdoor fan motor assembly provided in the first outdoor unit (11) stops. The opening degree of the outdoor expansion mechanism of the first outdoor unit (11) may be larger than the opening degree of the previous state (the opening degree when the outdoor heat exchanger of the first outdoor unit is the evaporator).

When the defrosting of the first outdoor unit 11 is completed and the defrosting of all the outdoor units is completed (S4), the process returns to step S1 and the outdoor heat exchangers 11, 12, 13 and 14 of the outdoor units 11, , 12, 13, 14) are in the evaporator state.

According to the present invention, even during the defrosting operation of the air conditioner, since the indoor unit performs the heating operation, continuous heating of the room can be performed and the pleasantness of the room can be maintained.

Further, since the outdoor heat exchangers of the outdoor units sequentially operate defrosting without defrosting a part of the outdoor heat exchangers at the same time, there is an advantage that the decrease in the heating performance is minimized.

In addition, since the entire outdoor heat exchanger of each outdoor unit is defrosted, a phenomenon that a part remains in the outdoor unit is prevented.

1: outdoor unit 2: indoor unit
3: Dispenser

Claims (12)

An indoor unit including an indoor heat exchanger;
A plurality of outdoor units connected to the indoor unit and each including an outdoor heat exchanger, a compressor, and a four-way valve;
A high-pressure orifice in which the refrigerant compressed in the compressor flows, and which includes a second valve;
A low pressure engine for supplying refrigerant to the compressor through which the refrigerant evaporated in the indoor heat exchanger or the outdoor heat exchanger flows;
A liquid pipe through which the refrigerant condensed in the indoor heat exchanger or the outdoor heat exchanger flows; And
And a controller for controlling the plurality of outdoor units,
If the defrosting operation condition is satisfied during the heating operation,
The defrosting operation in which the four-way valve is switched and the second valve is closed is sequentially performed in a plurality of outdoor units,
Wherein the outdoor unit, in which the defrosting operation is performed,
And the defrosting operation is performed by compressing the refrigerant in the low-pressure engine in a compressor of an outdoor unit in which the defrosting operation is performed. The method according to claim 1,
Wherein each of the outdoor heat exchangers of the plurality of outdoor units is divided into a plurality of heat exchanging units through which the refrigerant can independently flow,
A multi-type air conditioner in which a plurality of heat exchangers are defrosted when a specific outdoor unit is defrosted. delete The method according to claim 1,
Wherein the defrost operation order of the plurality of outdoor units is determined according to the heat exchange capacity. 5. The method of claim 4,
A multi-type air conditioner in which an outdoor unit having a small capacity performs defrosting operation first. The method according to claim 1,
Wherein the defrosting operation of the plurality of outdoor units is performed according to a preset order. The method according to claim 1,
Wherein the outdoor fan provided in the outdoor unit performing the defrosting operation is stopped when the defrosting operation is performed. Indoor unit; A plurality of outdoor units each including an outdoor heat exchanger, a compressor, and a four-way valve; A high-pressure engine including a second valve; A low pressure engine for supplying the refrigerant to the compressor; A multi-type air conditioner comprising:
The plurality of outdoor units being operated in a heating mode;
Determining whether the defrosting operation condition is satisfied during the heating operation; And
Wherein when the defrost operation condition is satisfied, the plurality of outdoor units sequentially perform the defrost operation,
In the defrosting operation, each of the outdoor units for defrosting operation switches the four-way valve, closes the second valve,
Wherein the outdoor unit performing the defrosting operation compresses the refrigerant of the low-pressure orifice in a compressor of an outdoor unit that performs the defrosting operation to perform the defrosting operation. 9. The method of claim 8,
Wherein each of the outdoor heat exchangers of the plurality of outdoor units is divided into a plurality of heat exchanging units through which the refrigerant can independently flow,
Wherein when the specific outdoor unit is defrosted, all of the plurality of heat exchange units are defrosted. delete 9. The method of claim 8,
Wherein the step of sequentially performing the defrosting operation is such that the defrosting operation of the outdoor unit in the specific order is completed, and the defrosting operation of the outdoor unit in the next step is defrosting operation. 9. The method of claim 8,
And when the defrosting operation of the outdoor unit in a specific order is performed, the outdoor fan of the outdoor unit is stopped.

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