KR102399237B1 - Air conditioner and the method controlling the same - Google Patents

Abstract

An air conditioner according to an embodiment of the present invention includes a compressor for compressing a refrigerant; a discharge pipe connected to the discharge side of the compressor; a suction pipe connected to the suction side of the compressor; an outdoor heat exchanger provided with the heat transfer unit and the rear heat unit to exchange heat between the refrigerant and outdoor air; and a bypass pipe extending from the discharge pipe to the suction pipe. According to this, since the high-energy refrigerant flows into the outlet side of the evaporator through the bypass pipe to supplement the amount of heat of evaporation required in the defrost operation process of the post-heating unit, the post-heating unit can continuously operate as an evaporator.

Description

Air conditioner and the method controlling the same

The present invention relates to an air conditioner and a method for controlling the same.

An air conditioner is a device for maintaining the air in a predetermined space in the most suitable state according to the use and purpose. In general, the air conditioner includes a compressor, a condenser, an expansion device, and an evaporator, and a refrigerant cycle that performs compression, condensation, expansion and evaporation of the refrigerant is driven to cool or heat the predetermined space. .

The predetermined space may be variously proposed according to a place where the air conditioner is used. For example, when the air conditioner is disposed in a home or office, the predetermined space may be an indoor space of a house or a building.

When the air conditioner performs a cooling operation, the outdoor heat exchanger provided in the outdoor unit functions as a condenser, and the indoor heat exchanger provided in the indoor unit functions as an evaporator.

On the other hand, when the air conditioner performs a heating operation, the indoor heat exchanger functions as a condenser and the outdoor heat exchanger functions as an evaporator. In such a heat exchanger, the flow direction of the refrigerant is reversed during cooling and heating operations.

In the heating operation, since the refrigerant flowing through the outdoor heat exchanger absorbs heat and evaporates, the surface temperature of the outdoor heat exchanger is lowered. Accordingly, frost may form on the surface of the outdoor heat exchanger, which may cause a problem in that heat exchange efficiency is lowered. Accordingly, the air conditioner performs a defrosting operation to remove the frost on the surface of the outdoor heat exchanger in the heating operation.

The conventional defrosting operation removes the frost by reversing the circulation of the refrigerant during the heating operation so that the outdoor heat exchanger performs the condenser function. Consequently, in the conventional defrosting operation, since indoor heating is stopped, there is a problem of lowering the indoor temperature, and there is a problem that it takes a long time to reheat the air for a heating operation again after the defrost operation is finished.

Due to the above-described problems, there is a need for an air conditioner that can continuously perform indoor heating while performing a defrosting operation during a heating operation.

Prior literature information related to this is as follows.

1. Publication number (disclosure date): 10-2013-0039582 (April 22, 2013)

Title of Invention: Air conditioner and defrosting method of air conditioner

In the preceding document, an embodiment of maintaining indoor heating by operating a heat transfer unit of an outdoor heat exchanger as a condenser during a heating operation to perform defrosting and maintaining a rear heat unit of the outdoor heat exchanger as an evaporator is disclosed.

However, the prior literature has the following problems.

There is a disadvantage in that only when the heat transfer part of the outdoor heat exchanger is defrosted (condenser), the rear heat part of the outdoor heat exchanger can be maintained as an evaporator. That is, the defrosting operation for maintaining the heating operation is limited to the case of defrosting the heat transfer unit.

As a result, in order to defrost the post-heating unit, there is a problem in that it is necessary to convert the cooling cycle to operate the entire heat-transducing unit and the post-heating unit as a condenser ('cooling defrost').

Since the cooling defrost for the post-heating unit is substantially converted to a cooling operation, there is a problem in that it is difficult to continuously maintain the heating operation. That is, when the cooling and defrosting is performed, since the entire outdoor heat exchanger operates as a condenser, there is a problem in that the indoor temperature is reduced. As a result, after the cooling and defrosting is finished, it may take a lot of time to heat the indoor air again.

An object of the present invention is to provide an air conditioner capable of performing a heating operation while simultaneously performing a defrosting operation and a control method thereof.

Another object of the present invention is to provide an air conditioner capable of solving a problem in which it is difficult to continuously maintain a heating operation when a defrosting operation is performed and a method for controlling the same.

Another object of the present invention is to provide an air conditioner capable of minimizing a decrease in heating capacity during a defrosting operation and a control method thereof.

Another object of the present invention is to provide an air conditioner capable of solving a problem of consuming a relatively long time to heat indoor air after a defrosting operation is performed and a control method thereof.

Another object of the present invention is to provide an air conditioner capable of realizing optimum performance in consideration of characteristics of a refrigerant passing through a condenser and a characteristic of a refrigerant passing through an evaporator, and a control method thereof.

In order to achieve the above object, an air conditioner according to an embodiment of the present invention includes a compressor for compressing a refrigerant; a discharge pipe connected to the discharge side of the compressor; a suction pipe connected to the suction side of the compressor; an outdoor heat exchanger provided with the heat transfer unit and the rear heat unit to exchange heat between the refrigerant and outdoor air; and a bypass pipe extending from the discharge pipe to the suction pipe. According to this, since the high-energy refrigerant flows into the outlet side of the evaporator through the bypass pipe to supplement the heat of evaporation required in the defrost operation process of the post-heating unit, the post-heating unit can continuously operate as an evaporator.

In addition, the air conditioner according to an embodiment of the present invention includes a temperature sensor for detecting whether the heat transfer unit and the rear heat unit are implanted; and a control unit configured to perform control based on the detection result of the temperature sensor.

In addition, the air conditioner according to an embodiment of the present invention further includes a hot gas valve installed in the bypass pipe, wherein the control unit opens the hot gas valve when the post-heating part is implanted. do it with And, the control unit, characterized in that the increase in the operating frequency of the compressor when the idea of the post-heating unit. According to this, it is possible to supplement the amount of heat of evaporation and refrigerant flow that are insufficient in the defrosting process of the after-heating part.

In addition, the air conditioner according to an embodiment of the present invention may include: a serial pipe connecting an outlet port of the heat transfer unit and an inlet port of the rear heat unit; and a first valve installed in the series pipe, wherein the control unit adjusts the opening degree of the first valve so that the evaporation temperature of the back heat section rises by a set temperature when the post heat section is conceived. . According to this, the evaporation temperature of the post-heating part can be formed higher than the freezing point of the frost, so that the temperature of the surface of the back-heating part can be raised. After all, it is possible to defrost the back heat part.

In addition, the suction pipe, a first suction pipe for guiding the evaporated refrigerant to the accumulator; and a second suction pipe extending from the accumulator to the suction side of the compressor.

In addition, an air conditioner according to an embodiment of the present invention may include: an indoor heat exchanger configured to exchange heat between the refrigerant and indoor air; a connection pipe extending from the indoor heat exchanger to the inlet port of the heat transfer unit; and a branch pipe branching from the connection pipe and extending to the inlet port of the rear heat part.

In addition, the air conditioner according to an embodiment of the present invention, the discharge pipe and the suction pipe are connected, the flow conversion unit for changing the flow direction of the refrigerant; a heat transfer pipe extending from the outlet port of the heat transfer unit to the flow conversion unit; a back heat pipe branching from the heat transfer pipe and extending to an outlet port of the back heat part; and a second valve installed on the heat transfer pipe.

In another aspect, an air conditioner control method according to an embodiment of the present invention includes the steps of: determining whether a heating operation is performed in an air conditioner including a compressor, an outdoor heat exchanger having a heat transfer unit and a rear heat unit, and an expansion valve; determining whether the heat transfer unit is implanted; opening a first valve installed in a series pipe connecting the outlet port of the heat transfer unit and the inlet port of the rear heat unit when the heat transfer unit is conceived; determining whether the rear heating part is implanted; expanding the pressure of the refrigerant passing through the first valve to a preset pressure when the post-heating unit is implanted; and bypassing the compressed refrigerant to the suction side of the compressor by a bypass pipe branched from the discharge side of the compressor, wherein the preset pressure is a pressure that increases the evaporation temperature of the rear heat unit . Accordingly, since the post-heating unit can continuously operate as an evaporator, it is possible to continuously provide heating to the room.

In addition, the evaporation temperature of the post-heat part is characterized in that it is higher than the freezing point of the frost.

In addition, the method for controlling an air conditioner according to an embodiment of the present invention further includes the step of increasing the operating frequency of the compressor when the rear heat part is implanted.

In addition, the method for controlling an air conditioner according to an embodiment of the present invention includes the steps of: determining whether defrosting of a rear heating unit is completed; and returning to the heating operation when the defrosting of the heat transfer unit and the rear heat unit is completed, wherein the returning to the heating operation includes closing the first valve and the hot gas valve installed in the bypass pipe; , characterized in that the second valve installed on the outlet side of the heat transfer unit is opened. Accordingly, the refrigerant passing through the outdoor heat exchanger may pass through the heat transfer unit and the rear heat unit in parallel in the heating operation, and may pass through the heat transfer unit and the post heat unit in series in the defrost operation and the cooling operation.

According to the present invention, there is an advantage in that the heating operation can be continuously performed even during the defrosting operation because the entire heat transfer unit and the rear heat unit operate as a condenser and thus do not perform a defrosting operation. Accordingly, it is possible to continuously provide warm air to the room.

According to the present invention, there is an advantage in that it is possible to minimize the decrease in heating capacity due to the defrosting operation.

According to the present invention, since indoor heating can be continuously maintained, it is possible to shorten the consumption time for reheating the indoor air after the defrosting operation is performed.

According to the present invention, since it is possible to vary the flow path of the refrigerant passing through the outdoor heat exchanger according to the cooling and heating operation, it is possible to improve the efficiency according to the operation of the condenser or the evaporator. That is, it is possible to improve the performance of the air conditioner.

According to the present invention, warm air generated by passing through one heat exchange unit (heat front unit) performing a condensation function during the defrosting operation is provided to another heat exchange unit (rear heat unit) performing an evaporation function and converted into heat energy. There are advantages to using it. According to this, it is possible to reduce the amount of implantation in the heat exchanger performing the evaporation function.

According to the present invention, it is possible to improve the heat exchange efficiency of the outdoor heat exchanger through the defrosting operation.

1 is a view schematically showing the configuration of an air conditioner according to an embodiment of the present invention;
2 is a block diagram illustrating a control unit of an air conditioner according to an embodiment of the present invention;
3 is a view showing a cooling operation of the air conditioner according to an embodiment of the present invention;
4 is a view showing a heating operation of the air conditioner according to an embodiment of the present invention;
5 is a view showing a defrosting operation of the air conditioner according to an embodiment of the present invention;
6 is a view showing a PH diagram of an air conditioner according to an embodiment of the present invention;
7 is a flowchart illustrating a control method for a defrosting operation of an air conditioner according to an embodiment of the present invention;

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, the spirit of the present invention is not limited to the embodiments presented below, and those skilled in the art who understand the spirit of the present invention may change other embodiments included within the scope of the same spirit by adding, changing, deleting, and adding components. It will be easy to implement, but this will also be included within the scope of the present invention.

In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the embodiment of the present invention, if it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When it is described that a component is "connected", "coupled" or "connected" to another component, the component may be directly connected or connected to the other component, but another component is between each component. It will be understood that may also be "connected", "coupled" or "connected".

1 is a diagram schematically showing the configuration of an air conditioner according to an embodiment of the present invention, and is a block diagram showing a control unit of the air conditioner according to a first embodiment of the present invention.

1 and 2 , the air conditioner according to the first embodiment of the present invention may include an outdoor unit 10 disposed outdoors and an indoor unit 20 disposed indoors. In addition, the air conditioner may further include a controller 30 for controlling the outdoor unit 10 and the indoor unit 20 to perform a cooling operation, a heating operation, a defrosting operation, and the like.

The indoor unit 20 includes an indoor heat exchanger (not shown) in which incoming indoor air and refrigerant exchange heat, and a first indoor pipe 21 and a second indoor pipe 22 connected to inlet and outlet sides to guide the refrigerant. may include

The indoor unit 20 may be connected to the outdoor unit 10 by the first indoor pipe 21 and the second indoor pipe 22 . In detail, the first indoor pipe 21 may extend from the indoor unit 20 to the first indoor connection part 23 provided in the outdoor unit 10 . In addition, the second indoor pipe 22 may extend from the indoor unit 20 to the second indoor connection part 24 provided in the outdoor unit 10 .

That is, the first indoor connection part 23 and the second indoor connection part 24 can be understood as entrances and exits through which the refrigerant flows into the outdoor unit 10 or the refrigerant flows out from the outdoor unit 10 .

The first indoor connection part 23 may be provided such that a first connection pipe 111 to be described later and the first indoor pipe 21 are connected to each other, and the second indoor connection part 24 is a second connection pipe to be described later. (112) and the second indoor pipe (22) may be provided to be connected. In addition, the first indoor connection part 23 and the second indoor connection part 24 may include a valve for controlling the flow of refrigerant.

Meanwhile, the first indoor pipe 21 may be integrally formed with the first connecting pipe 111 , and the second indoor pipe 22 may be integrally formed with the second connecting pipe 112 .

The outdoor unit 10 includes a compressor 100 for compressing a refrigerant, a flow conversion unit 110 for changing a flow direction of the refrigerant, an outdoor heat exchanger 120 for exchanging heat between the refrigerant and outdoor air, and the outdoor heat exchanger 120 . ) may include an outdoor fan 130 that provides a flow force so that the outdoor air flows in one direction.

An outlet side of the compressor 100 may include a discharge pipe 101 . The discharge pipe 101 may guide the high-temperature, high-pressure refrigerant discharged from the compressor 100 through a compression process to the flow conversion unit 110 . In addition, the discharge pipe 101 may extend from the outlet side of the compressor 100 to the flow conversion unit 110 .

Meanwhile, the discharge pipe 101 may include a discharge branch 105 for branching the refrigerant discharged from the compressor 100 to the bypass pipe 180 . A detailed description related thereto will be provided later.

The suction side of the compressor 100 may include suction pipes 141 and 142 . The suction pipes 141 and 142 may guide the refrigerant evaporated through heat exchange to the compressor 100 . In addition, the suction pipes 141 and 142 may extend from the inlet side of the compressor 100 to the flow conversion unit 110 .

The suction pipes 141 and 142 may include a suction branch 187 . A bypass pipe 180 to be described later is connected to the suction branch 187 . In addition, the suction branch 187 may guide the refrigerant discharged from the compressor 100 to be bypassed by the bypass pipe 180 and introduced into the suction pipes 141 and 142 .

Meanwhile, the outdoor unit 10 may further include the compressor 100 and an accumulator 140 disposed on the suction side. The accumulator 140 may perform a function of introducing a refrigerant that has passed through an evaporator (an outdoor heat exchanger or an indoor heat exchanger) and separating the refrigerant into a gaseous phase and a liquid phase. In addition, the accumulator 140 may provide a gaseous refrigerant to the compressor 100 .

In this case, the suction pipes 141 and 142 are connected to the first suction pipe 141 extending from the flow conversion unit 110 to the accumulator 140 and from the accumulator 140 to the compressor 100 . It may include a second suction pipe 142 that extends.

Meanwhile, a sensor (not shown) for detecting the temperature of the compressed refrigerant may be installed in the compressor 100 .

The flow conversion unit 110 may include a four way valve. In addition, the flow conversion unit 110 may change the flow direction of the refrigerant toward the outdoor heat exchanger 120 or the indoor unit 20 . For example, the control unit 30 may determine whether a heating operation or a cooling operation is performed and control the flow conversion unit 110 to determine the flow direction of the refrigerant.

When the air conditioner performs a cooling operation, the refrigerant discharged from the compressor 100 flows from the flow conversion unit 110 to the outdoor heat exchanger 120 , and an indoor heat exchanger (not shown) of the indoor unit 20 . ), the evaporated refrigerant may be introduced into the accumulator 140 through the flow conversion unit 110 .

On the other hand, when the air conditioner performs a heating operation, the refrigerant discharged from the compressor 100 flows from the flow conversion unit 110 to the indoor heat exchanger of the indoor unit 20 and evaporates in the outdoor heat exchanger 120 . The cooled refrigerant may be introduced into the accumulator 140 through the flow conversion unit 110 .

In the flow conversion part 110 , the discharge pipe 101 , the first suction pipe 141 , the first connection pipe 111 extending to the first indoor connection part 23 , and the outdoor heat exchanger 120 . ) may be connected to the fourth connecting pipe 114 extending to.

The first connecting pipe 111 may extend from the flow conversion unit 110 to the first indoor connecting unit 23 , and may be connected to the first indoor pipe 21 by the first indoor connecting unit 23 . there is.

Meanwhile, the second connecting pipe 112 may be connected to the second indoor pipe 22 by the second indoor connecting part 24 . That is, the second connection pipe 112 extends from the second indoor connection part 24 to the outdoor heat exchanger 120 .

The fourth connection pipe 114 extends from the flow conversion unit 110 to the outdoor heat exchanger 120 . In addition, the fourth connection pipe 114 includes a second branch 154 for branching or laminating the flow of refrigerant, and a heat transfer pipe 160 extending from the second branch 154 to a heat transfer part 121 to be described later. ) and a back heat pipe 153 extending from the second branch part 154 to a back heat part 125 to be described later. A detailed description related thereto will be provided later.

In the outdoor heat exchanger 120 , heat exchange occurs between the outdoor air flowing into the outdoor unit 10 and the refrigerant.

The outdoor heat exchanger 120 may include a heat transfer unit 121 and a rear heat unit 125 . In addition, the heat transfer unit 121 and the rear heat unit 125 are located inside the outdoor heat exchanger 120 and may include a plurality of refrigerant pipes through which the refrigerant flows.

The heat transfer unit 121 and the rear heat unit 125 include two pipes branching from the second connection pipe 112 by the first branch 150 and a fourth connection pipe ( 114) and may be connected in parallel by two pipes branching from each other.

In addition, the heat transfer unit 121 and the rear heat unit 125 may be positioned side by side along the air flow direction by the outdoor fan 130 . That is, the heat transfer unit 121 and the rear heat unit 125 may be disposed to be parallel to each other.

The heat transfer unit 121 may be located on the outside facing the outdoor fan 130 , and the rear heat unit 125 may be located inside the rear of the heat transfer unit 121 . That is, the heat transfer unit 121 is located at a close distance to the outdoor fan 130 , and the rear heat unit 125 is located at a relatively distant distance from the outdoor fan 130 .

Accordingly, when the outdoor fan 130 rotates in a forward direction and the outdoor air flows in a flow direction into the outdoor unit 10 , the outdoor air first contacts the heat transfer unit 121 and then flows to the rear heat unit 125 . A flowing stream can be formed.

The outdoor unit 10 includes an implantation detecting means 122 and 126 for detecting an implantation of the outdoor heat exchanger 120, and an evaporation temperature detecting means for detecting an evaporation temperature of the refrigerant passing through the outdoor heat exchanger 120 ( It may further include an outdoor temperature sensor (not shown) for detecting the outdoor temperature) and the outdoor temperature.

The implantation detecting means (122, 126) includes a first temperature sensor 122 capable of detecting an implantation of the heat transfer unit 121, and a second temperature sensor 126 capable of detecting an implantation of the rear heating unit 125. may include

The control unit 30 controls the heat transfer unit 121 and the rear heat unit 122 based on the information sensed from the first temperature sensor 122, the second temperature sensor 126, and the outdoor temperature sensor (not shown). It can be judged whether or not

The control unit 30 controls the heat transfer unit 121 and the rear heat unit 122 based on the information sensed from the first temperature sensor 122, the second temperature sensor 126, and the outdoor temperature sensor (not shown). It can be judged whether or not For example, when the outdoor temperature is 0 (°C) or higher, the control unit 30 defrosts when the temperature measured by the first temperature sensor 122 or the second temperature sensor 126 is less than -7 (°C) You can control it to start driving.

In addition, the control unit 30 may control the compressor 100, the outdoor fan 130, the expansion valves 131 and 135, the first and second valves 117 and 165, and the hot gas valve 185 according to the result of the determination of whether or not there is an idea. there is.

In addition, the control unit 30 may sense the evaporation temperature of the refrigerant when the outdoor heat exchanger 120 operates as an evaporator by the evaporation temperature detecting means (not shown).

Also, the control unit 30 may detect the evaporation temperature and increase the operating frequency of the compressor 100 according to a preset table. For example, the controller 30 may control the operating frequency of the compressor 100 by sensing the evaporation temperature when an implantation occurs in the post-heating unit 125 .

Meanwhile, the second connection pipe 112 may be connected to the heat transfer unit 121 . In more detail, the second connection pipe 112 may extend from the second indoor connection part 24 to the first port of the heat transfer part 121 to guide the refrigerant.

Also, the fourth connection pipe 114 may be connected to the heat transfer unit 121 . In more detail, the fourth connection pipe 114 may be connected to the heat transfer unit 121 by a heat transfer pipe 160 extending from the second branch 154 to the second port of the heat transfer unit 121 . .

Here, the first port and the second port may be understood as separate entrances through which the refrigerant flows in or out. Therefore, for convenience of explanation, based on the heating operation, the first port is called an inlet port or an inlet port of the heat transfer unit 121 , and the second port is an outlet side or outflow port of the heat transfer unit 121 . Name it as a port.

As described above, the heat transfer unit 121 and the rear heat unit 125 may be connected in parallel. Accordingly, the second connecting pipe 112 and the fourth connecting pipe 114 may include branch portions 150 and 154 for the parallel connection, respectively.

The second connecting pipe 112 may include a first branching part 150 capable of branching or laminating a flow path of a refrigerant to the heat transfer part 121 and the rear heat part 125 . The first branch part 150 may be formed at one point of the second connection pipe 112 . In addition, the first branch unit 150 may branch the refrigerant in the heating operation and perform a function of laminating the refrigerant in the cooling operation.

The first branch part 150 is connected to a branch pipe 151 extending to the rear heat part 125 . In addition, the branch pipe 151 may extend from the first branch part 150 to the first port of the rear heat part 125 .

In addition, the fourth connection pipe 114 may include a second branch part 154 for branching or laminating a flow path of a refrigerant to the heat transfer part 121 and the rear heat part 125 . The second branch 154 may be formed at one point of the fourth connecting pipe 114 . In addition, the second branch unit 154 may perform a function of laminating the refrigerant in the heating operation and branching the refrigerant in the cooling operation.

The second branch 154 may connect the heat transfer pipe 160 extending to the heat transfer unit 121 and the back heat pipe 153 extending to the rear heat unit 125 . In addition, the back heat pipe 153 may extend from the second branch part 154 to the second port of the back heat part 125 .

The first port and the second port of the rear heat unit 125 may be understood as separate entrances through which the refrigerant flows in or out. Therefore, for convenience of explanation, based on the heating operation, the first port is called an inlet port or an inlet port of the back heat unit 121 , and the second port is an outlet side or outflow port of the back heat unit 121 . Name it as a port.

Accordingly, in the heating operation, the refrigerant flowing through the second connection pipe 112 may be branched into the heat transfer unit 121 and the rear heat unit 125 by the first branch unit 150 to flow. In addition, the refrigerant that has passed through the heat transfer unit 121 and the rear heat unit 125 is combined in the second branch unit 161 , and the laminated refrigerant flows through the flow conversion unit along the fourth connection pipe 114 . It flows to 110 , flows into the first suction pipe 141 , and can finally be recovered by the compressor 100 .

Meanwhile, the outdoor unit 10 may further include a narrow tube (not shown) capable of branching the refrigerant flowing into the outdoor heat exchanger 120 . In detail, the narrow tube may be respectively located at the first port of the heat transfer unit 121 and the first port of the rear heat unit 125 . For example, the narrow tube (not shown) may be positioned between the first port of the rear heating unit 125 and the rear heating branch unit 152 . In addition, one side of the narrow pipe may be connected to the branch pipe 151 , and the other side may be connected to a plurality of refrigerant pipes forming the first port of the rear heat unit 125 .

The narrow tube branches a plurality of flow paths of the refrigerant flowing into the heat transfer unit 121 and/or the rear heat unit 125 , or the flow of the refrigerant that has passed through the heat transfer unit 121 and/or the rear heat unit 125 . Routes can be merged into one.

In addition, the narrow tube may perform a function of adjusting the pressure of the refrigerant passing therethrough. Accordingly, the pressure of the refrigerant passing through the narrow tube may be increased within a predetermined range according to the specification of the narrow tube installed in the outdoor heat exchanger 120 , thereby increasing the evaporation temperature of the refrigerant.

Meanwhile, the heat transfer unit 121 and the rear heat unit 125 of the outdoor heat exchanger 120 are connected in parallel in the heating operation and in series in the cooling operation.

Hereinafter, a configuration for serial connection of the heat transfer unit 121 and the rear heat unit 125 will be described.

The outdoor unit 10 may further include a third connection pipe 113 connecting the heat transfer unit 121 and the rear heat unit 125 in series.

The third connection pipe 113 extends from the heat transfer pipe 160 to the branch pipe 151 .

The third connection pipe 113 may connect the outlet port of the heat transfer unit 121 and the inlet port of the rear heat unit 125 . That is, based on the heating operation, the third connection pipe 113 may extend from the outlet side of the heat transfer unit 121 to the inlet side of the rear heat unit 125 .

On the other hand, the third connecting pipe 113 may be called a series pipe 113 because it connects the front heat part 121 and the rear heat part 125 in series.

The branch pipe 151 may include a post-heat branch 152 positioned between the first branch 150 and a first port of the back-heat part 125 .

The post heat branch 184 may connect the third connecting pipe 113 . That is, the branch pipe 151 and the third connection pipe 113 may be connected to each other by the post heat branch unit 184 .

The post heat branch unit 184 may guide the refrigerant that has passed through the post heat unit 125 to flow into the third connection pipe 113 when a cooling operation is performed. In addition, the post heat branch unit 184 may guide the refrigerant flowing into the third connection pipe 113 to flow into the branch pipe 151 when a defrosting operation is performed.

The heat transfer pipe 160 may include a heat transfer branch 167 positioned between the second branch 154 and the second port of the heat transfer unit 121 .

The heat transfer branch 167 may connect the third connecting pipe 113 . That is, the heat transfer pipe 160 and the third connection pipe 113 may be connected by the heat transfer branch 167 .

The heat transfer branch unit 167 may guide the refrigerant flowing through the third connection pipe 113 to flow into the heat transfer unit 112 when a cooling operation is performed. In addition, when the defrosting operation is performed, the heat transfer branch unit 167 may guide the refrigerant flowing into the heat transfer pipe 160 through the heat transfer unit 121 to flow into the third connection pipe 113 . .

Accordingly, in the cooling operation, the refrigerant flowing through the fourth connection pipe 114 may be introduced into the back heat unit 125 along the post heat pipe 153 . The refrigerant introduced into the branch pipe 151 through the post heat branch 125 may flow into the third connection pipe 113 through the post heat branch part 152 . The refrigerant introduced into the third connection pipe 113 may flow into the heat transfer pipe 160 through the heat transfer branch 167 and flow to the heat transfer unit 121 . The refrigerant passing through the heat transfer unit may flow to the indoor unit 20 along the second connection pipe 112 .

Meanwhile, the front heat branch unit 167 may be referred to as a third branch unit 167 , and the post heat branch unit 152 may be referred to as a fourth branch unit 152 . That is, the third connecting pipe 113 may connect the third branch 167 and the fourth branch 152 to each other.

The third connection pipe 113 may further include a first valve 117 capable of selectively controlling a flowing refrigerant. For example, the first valve 230 includes a solenoid valve and an electromagnetic expansion valve ( EEV) may be included.

The first valve 117 may be positioned between the front heat branch 167 and the post heat branch 152 . In addition, the first valve 117 may control that the refrigerant flows into the third connection pipe 113 through an opening/closing operation.

The heat transfer pipe 160 may further include a second valve 165 capable of selectively controlling a flowing refrigerant. For example, the second valve 165 may include a solenoid valve and an electronic expansion valve (EEV).

The second valve 165 may be positioned between the second branch 154 and the electrothermal branch 167 . In addition, the second valve 165 may control the refrigerant flowing into the heat transfer pipe 160 through an opening/closing operation.

In the heating mode, depending on whether the first valve 117 and the second valve 165 are open/closed, the refrigerant that has passed through the heat transfer unit 121 is transferred to the rear heat unit 125 . can be selectively introduced.

For example, when the second valve 165 is opened, the refrigerant that has passed through the heat transfer unit 121 flows into the fourth connection pipe 114 through the heat transfer pipe 160 . At this time, the first valve 220 provided to the third connection pipe 113 may be closed.

As another example, when the second valve 165 is closed for a defrost operation, the refrigerant passing through the heat transfer unit 121 passes through the heat transfer pipe 160 and the heat transfer branch unit 167 to the third connection pipe ( 113) is introduced. At this time, the first valve 220 provided to the third connection pipe 113 may be opened.

In addition, in the cooling mode, the second valve 165 may be closed so that the refrigerant flowing through the fourth connection pipe 114 flows into the post heat pipe 153 . In addition, the first valve 117 may be opened to guide the refrigerant that has passed through the rear heat unit 125 to flow into the heat transfer unit 121 .

Meanwhile, the outdoor unit 10 may further include expansion valves 131 and 135 . For example, the expansion valves 131 and 135 may include an electronic expansion valve (EEV) capable of reducing the pressure of the refrigerant.

The expansion valves 131 and 135 may include a first expansion valve 131 installed on the second connection pipe 112 and a second expansion valve 135 installed on the branch pipe 151 . In addition, the first expansion valve 131 and the second expansion valve 135 may be disposed in parallel to correspond to the arrangement of the heat transfer unit 121 and the rear heat unit 125 .

The first expansion valve 131 may be positioned between the first branch 150 and the first port of the heat transfer unit 121 .

In the heating operation, the first expansion valve 131 may expand the condensed refrigerant to provide it to the heat transfer unit 121 .

The second expansion valve 135 may be positioned between the first branch part 150 and the first port of the rear heat part 125 . In detail, it may be positioned between the first branching part 150 and the post-heating branching part 152 .

In the heating operation, the second expansion valve 135 may expand the condensed refrigerant to provide it to the post-heating unit 125 .

Meanwhile, the outdoor unit 10 may further include an orifice (not shown) installed in the branch pipe 151 .

The orifice (not shown) may be positioned between the back heat branch part 152 and the first port of the back heat part 125 .

The orifice (not shown) may perform a function of increasing the pressure and temperature of the refrigerant passing through the branch pipe 151 when a defrosting operation is performed. For example, when an implantation occurs in the rear heat unit 125 , the pressure of the refrigerant introduced into the branch pipe 151 through the third connection pipe 113 may be adjusted while passing through the orifice. Accordingly, the evaporation temperature of the refrigerant in the rear heat unit 125 may increase. As a result, when the evaporation temperature reaches a preset temperature (for example, 0 °C), the defrosting operation in which the evaporation temperature rises while the rear heat unit 125 operates as an evaporator to remove the frost on the surface. can be performed.

Of course, the function of the orifice may be performed by the above-described first valve 117 and a narrow pipe (not shown). For example, the control unit 30 may adjust the opening degree of the first valve 117 so that the evaporation temperature in the rear heat unit 125 rises by a preset temperature using the evaporation temperature sensing means.

Hereinafter, it will be described on the basis that the first valve 117 controls the evaporation pressure and the evaporation temperature of the refrigerant passing through the after-heating unit 125 during the heating operation.

Meanwhile, as described above, the discharge pipe 101 may include a discharge branch unit 105 for branching the refrigerant discharged from the compressor 100 into the bypass pipes 180 and 183 . The discharge branch 105 may be formed at one point of the discharge pipe 101 .

That is, the refrigerant discharged from the compressor 100 flows to the flow conversion unit 110 or to the first suction pipe 141 or the second suction pipe 142 through the bypass pipe 180 . may be bypassed.

The outdoor unit 10 may include a bypass pipe 180 for injecting the refrigerant of the discharge pipe 101 into the first suction pipe 141 or the second suction pipe 142 . .

The bypass pipe 180 is branched from the discharge pipe 101 to bypass the high-temperature compressed refrigerant toward the suction side of the compressor 100 . Accordingly, for the defrosting operation of the post-heating unit 125 , there is an advantage in that the additional heat of evaporation required by increasing the evaporation temperature of the post-heating unit 125 can be provided through the bypass of the compressed refrigerant.

The bypass pipe 180 may extend from the discharge pipe 101 to the suction pipes 141 and 142 to bypass the compressed refrigerant. That is, the bypass pipe 180 may extend from the discharge pipe 101 to the first suction pipe 141 or the second suction pipe 142 .

In more detail, the bypass pipe 180 may extend from the discharge branch 105 to the suction branch 187 . Accordingly, the bypass pipe 180 may allow the refrigerant branched from the discharge pipe 101 to flow into the suction pipes 141 and 142 through the suction branch 187 .

The bypass pipe 180 includes a hot gas valve 185 with an adjustable opening degree to selectively bypass the high-temperature and high-pressure compressed refrigerant discharged from the compressor 100 to the suction pipes 141 and 142 . can do. For example, the hot gas valve 185 may include an Electronic Expansion Valve (EEV) capable of reducing the pressure of the refrigerant.

The hot gas valve 185 may be installed in the bypass pipe 180 . In detail, the hot gas valve 185 may be positioned between the suction branch 187 and the discharge branch 105 .

As described above, the heat transfer unit 121 and the rear heat unit 125 of the outdoor heat exchanger 120 are connected in parallel in the heating operation and in series in the cooling operation. That is, the refrigerant flowing through the outdoor heat exchanger 120 may have a flow path selected by switching operations of the first and second valves 117 and 165 and the first and second expansion valves 131 and 135 .

In other words, the air conditioner according to the embodiment of the present invention may have a variable path so that the refrigerant flowing through the outdoor heat exchanger 120 has a different flow path depending on a cooling operation or a heating operation. can

As described above, the reason for changing the path of the refrigerant passing through the outdoor heat exchanger 120 according to the cooling operation or the heating operation is to secure optimum efficiency in consideration of the characteristics of the refrigerant flowing through the condenser and the evaporator. .

In detail, the refrigerant passing through the condenser is a high-pressure refrigerant and has a relatively small specific volume, and the refrigerant passing through the evaporator is a low-pressure refrigerant and has a relatively large specific volume. Due to this specific volume difference, since the pressure loss of the refrigerant passing through the condenser is relatively small, the more the mass flow rate is increased, the closer to the ideal heat exchange efficiency. On the other hand, since the refrigerant passing through the evaporator has a relatively large pressure loss, as the mass flow rate is reduced, the ideal heat exchange efficiency can be approached. After all, in the air conditioner technology field in which the efficiency of both the condenser and the evaporator must be considered, there is a problem that one cannot follow the optimal efficiency of any one.

In order to solve the above-described problem, according to an embodiment of the present invention, in the case of a cooling operation in which the outdoor heat exchanger 120 operates as a condenser, the heat transfer unit 121 and the rear heat unit 125 are connected in series to each other to obtain a refrigerant. The number of flow paths can be relatively small. In addition, in the case of a heating operation in which the outdoor heat exchanger 120 operates as an evaporator, the number of flow paths of the refrigerant may be relatively increased because the heat transfer unit 121 and the rear heat unit 125 are connected in parallel.

For example, the heat transfer unit 121 and the rear heat unit 125 may include a refrigerant flow path composed of a refrigerant pipe through which the refrigerant flows, respectively, and the number of the refrigerant flow paths is eight paths. can be provided respectively. In this case, eight (8) paths are maintained in the case of a cooling operation in which the front heating unit 121 and the rear heating unit 125 are connected in series, and sixteen (16) paths are maintained in the case of a heating operation connected in parallel. can increase to

Accordingly, when the outdoor heat exchanger 120 operates as an evaporator, the mass flow rate of the refrigerant may be reduced because the number of paths is relatively increased. In addition, when the outdoor heat exchanger 120 operates as a condenser, the mass flow rate of the refrigerant may increase because the number of paths is relatively small. According to this, there is an advantage in that the optimum efficiency of the air conditioner can be realized.

3 is a view showing a cooling operation of the air conditioner according to an embodiment of the present invention, and FIG. 4 is a view showing a heating operation of the air conditioner according to an embodiment of the present invention.

In the air conditioner according to the embodiment of the present invention, when performing a cooling operation, the refrigerant may pass through the heat transfer unit 121 and the rear heat unit 125 in series.

A cooling operation process of the air conditioner according to an embodiment of the present invention will be described with reference to FIG. 3 .

In the cooling operation, the second expansion valve 135 , the hot gas valve 185 , and the second valve 165 are in a closed state, and the first valve 117 is opened. And the first expansion valve 131 may be opened to expand the refrigerant by adjusting the opening degree.

First, since the high-temperature, high-pressure compressed refrigerant discharged from the compressor 100 is in a closed state, the hot gas valve 185 is discharged through the flow conversion unit 110 along the discharge pipe 101 . 4 is introduced into the connection pipe 114 .

And, since the second valve 165 is in a closed state, the compressed refrigerant flows into the post heat pipe 153 through the second branch 154 . The refrigerant introduced into the post heat pipe 153 may flow into the post heat unit 125 to perform heat exchange (condensation).

Since the first valve 117 is opened and the second expansion valve 135 is closed 135, the refrigerant that has passed through the rear heat unit 125 is discharged to the third connection pipe 113. It flows into the heat transfer unit 121 . In addition, the refrigerant introduced into the heat transfer unit 121 may perform heat exchange (condensation). That is, the heat transfer unit 121 and the rear heat unit 125 are connected in series to operate as a condenser for condensing refrigerant through heat exchange with outdoor air.

The refrigerant that has passed through the heat transfer unit 121 flows along the second connection pipe 112 and is expanded by the first expansion valve 131 . And the refrigerant expanded by the first expansion valve 131 passes through the indoor heat exchanger of the indoor unit 20 . At this time, since the refrigerant is evaporated in the indoor heat exchanger, it is possible to provide cooling to the room by absorbing the heat of vaporization.

The refrigerant that has passed through the indoor heat exchanger flows into the first connection pipe 111 and flows to the suction pipes 141 and 142 through the flow conversion unit 110 . And the refrigerant introduced into the suction pipes 141 and 142 is recovered by the compressor 110 .

In the air conditioner according to the embodiment of the present invention, when a heating operation is performed, the refrigerant may pass through the heat transfer unit 121 and the rear heat unit 125 in parallel.

A heating operation process of the air conditioner according to the embodiment will be described with reference to FIG. 4 .

In the heating operation, the first valve 117 and the hot gas valve 185 are closed, and the first expansion valve 131 and the second expansion valve 135 are opened to adjust the opening degree of the refrigerant. can be inflated. And the second valve 165 is opened.

Since the compressed refrigerant discharged from the compressor 100 is in a closed state of the hot gas valve 185 , it passes through the flow conversion unit 110 along the discharge pipe 101 and the first connection pipe 111 . ) is introduced into The refrigerant is condensed through the indoor heat exchanger of the indoor unit 20 , and the condensed refrigerant is introduced into the second connection pipe 112 through the second indoor pipe 22 .

In this case, the indoor heat exchanger may heat the room by using the heat of condensation generated while the refrigerant is condensed in the indoor heat exchanger.

The refrigerant introduced into the second connection pipe 112 is branched through the first branch part 150 , and a part passes through the first expansion valve 131 through the second connection pipe 112 , is expanded, and the remaining part is expanded by passing through the second expansion valve 135 through the branch pipe 151 .

That is, the refrigerant is expanded by the first expansion valve 131 and the second expansion valve 135 to lower the pressure and temperature.

The refrigerant that has passed through the first expansion valve 131 flows into the heat transfer unit 121 , and the refrigerant that has passed through the second expansion valve 135 flows into the rear heat unit 125 . At this time, the heat transfer unit 121 and the rear heat unit 125 are connected in parallel to operate as an evaporator for evaporating refrigerant through heat exchange with outdoor air.

The refrigerant flowing into the heat transfer unit 121 and the rear heat unit 125 is heat-exchanged and evaporated. Since the first valve 117 is closed and the second valve 165 is open, the refrigerant evaporated from the heat transfer unit 121 flows into the heat transfer pipe 160 and flows into the second branch unit 154 . ), and the refrigerant evaporated in the post heat unit 125 flows into the post heat pipe 153 and passes through the second branch unit 154 . As a result, the refrigerant evaporated from each of the heat transfer unit 121 and the rear heat unit 125 is combined in the second branch unit 154 , and the combined refrigerant flows through the fourth connection pipe 114 . It flows into the suction pipes 141 and 142 through the part 110 . And the refrigerant introduced into the suction pipe 141 is recovered to the compressor 110 .

On the other hand, when the heating operation is performed for a long time, the surface temperature of the outdoor heat exchanger 120 may be significantly lowered because the refrigerant evaporates in the outdoor heat exchanger 120 . In this case, frost may occur on the surface of the outdoor heat exchanger 120 . In particular, the heat exchange unit (heat transfer unit or rear heat unit) that comes into contact with the outside air first may have a relatively large amount of implantation. Such frost formation causes a problem of lowering heat exchange performance because it exhibits an insulating effect in the outdoor heat exchanger 140 . Accordingly, the air conditioner may perform a defrosting operation by detecting an implantation of the outdoor heat exchanger while performing a heating operation.

5 is a view showing a defrosting operation of the air conditioner according to an embodiment of the present invention.

The defrosting operation may be started when it is determined that the occurrence of implantation is based on the detection result of at least one of the outdoor temperature sensor, the first temperature sensor 122 and the second temperature sensor 126 during the heating operation. For example, when the outdoor temperature is 0°C or higher, the defrost operation may be performed when the temperature sensed by the first temperature sensor 122 or the second temperature sensor 126 is less than -7°C.

Meanwhile, in the defrosting operation, the flow of the refrigerant may be switched by switching the operation of some valves during the heating operation. Therefore, in the following description of the defrosting operation, the refrigerant flow different from the heating operation process will be mainly described, and the same refrigerant flow as the heating operation process will be described above for the heating operation process.

Referring to FIG. 5 , in the defrosting operation, the first valve 117 and the first expansion valve 131 are opened, and the second expansion valve 135 and the second valve 220 are closed.

First, looking at the defrosting operation when an implantation occurs in the heat transfer unit 121 , the compressed refrigerant discharged from the compressor 100 is condensed in the indoor heat exchanger through the first connection pipe 111 . In addition, the refrigerant generates heat in a condensation process, and through this, heating can be provided to the room.

Since the second expansion valve 135 is closed, the condensed refrigerant passing through the indoor heat exchanger may pass through the first expansion valve 131 through the second connection pipe 112 .

At this time, the first expansion valve 131 does not expand the condensed refrigerant to the inlet pressure of the heat transfer unit 121 in the above-described heating operation, but expands to a pressure higher than that to be discharged at a relatively high temperature. can be adjusted.

That is, the first expansion valve 131 may expand the condensed refrigerant only to a state having sufficient temperature and pressure to defrost the frost formed on the heat transfer unit 121 . In addition, the temperature and pressure sufficient to defrost the frost implanted on the heat transfer unit 121 may be preset and stored according to a value sensed by the outdoor temperature sensor.

The high-temperature refrigerant that has passed through the first expansion valve 131 may flow into the heat transfer unit 121 . Accordingly, since a high-temperature refrigerant flows into the heat transfer unit 121 to generate heat through condensation, defrosting to remove the frost can be performed. That is, the heat transfer unit 121 may perform defrosting with heat of condensation.

Since the second valve 165 is closed, the refrigerant that has passed through the heat transfer unit 121 flows into the third connection pipe 113 through the heat transfer branch unit 167 .

In addition, the first valve 117 may expand the refrigerant passing through the third connection pipe 113 to a preset pressure. Accordingly, the refrigerant passing through the first valve 117 may be in a low temperature state.

That is, by adjusting the opening degree of the first valve 117 provided in the third connection pipe 113 , the refrigerant passing through the first valve 117 may be expanded to a low pressure and low temperature. In addition, the expanded refrigerant flows into the branch pipe 151 through the post heat branch 152 , and then flows into the post heat branch 125 .

Here, the preset pressure may vary depending on whether or not an implantation of the rear heat unit 125 occurs.

When the implantation does not occur in the rear heating unit 125 , the preset pressure may be the inlet pressure of the rear heating unit 125 in the heating operation described above. Accordingly, the refrigerant flowing into the post-heating unit 125 may be evaporated in the same manner as in the above-described heating operation.

On the other hand, when the conception occurs in the rear heating unit 125 , the preset pressure may be higher than the inlet pressure of the rear heating unit 125 in the above-described heating operation.

When an implantation occurs in the back heat unit 125 , the control unit 30 controls the opening degree of the first valve 117 so that the temperature of the surface of the back heat unit 125 generates frost (freezing point) In order to achieve the above, the evaporation temperature of the post-heating unit 125 may be increased. In this case, the evaporation temperature of the rear heating unit 125 may be determined by the preset pressure.

The preset pressure may be tabled as a pressure value corresponding to the outdoor temperature and stored in advance in the air conditioner. For example, the controller 30 may determine the expansion pressure of the refrigerant corresponding to the temperature sensed by the outdoor temperature sensor (not shown) when the rear heat unit 125 is conceived. In addition, the control unit 30 may control the opening degree of the first valve 117 to expand the refrigerant to the determined pressure. The refrigerant expanded to the determined pressure may increase the evaporation temperature of the rear heat unit 125 to a predetermined set temperature. Accordingly, the evaporation temperature of the post-heating unit 125 may be increased compared to the case of the above-described heating operation.

In this case, it can be understood that the increased evaporation temperature of the rear heating unit 125 is a set temperature capable of removing the frost formed on the rear heating unit 125 . And the set temperature may be higher than the freezing point (condensation point) of the material that generates the frost. As an example, the set temperature may be set higher than the freezing point of the submersible contained in the air. In addition, the preset pressure may be determined as a pressure capable of raising the evaporation temperature (ie, the set temperature) of the rear heat unit 125 to 0°C.

In summary, the first valve 117 may expand the refrigerant passing through it to a preset pressure. In addition, the refrigerant expanded to the preset pressure may increase the evaporation temperature of the rear heat unit 125 . At this time, since the increased evaporation temperature is set to a temperature above the freezing point of the surface of the rear heating unit 125 , the frost implanted on the rear heating unit 125 is melted and defrosted.

In addition, the evaporation temperature of the refrigerant passing through the post-heating unit 125 may be monitored by an evaporation temperature sensing means. That is, the control unit 30 may control the opening degree of the first valve 117 based on the result sensed by the evaporation temperature sensing means. Accordingly, the first valve 117 may expand the refrigerant so that the evaporation temperature of the rear heat unit 125 can accurately satisfy a predetermined temperature. For example, the control unit 30 may expand the refrigerant so that the evaporation temperature of the rear heat unit 125 satisfies 0°C by adjusting the opening degree of the first valve 117 .

The evaporation temperature of the back heat part 125, which is increased based on the outdoor temperature, may make the temperature of the surface of the back heat part 125 to be greater than or equal to a temperature (freezing point) that generates frost. Accordingly, the frost formed on the rear heating unit 125 may be removed. In this case, the post-heating unit 125 may operate as an evaporator while defrosting is performed.

Of course, when the idea is generated in the rear heat unit 125, the pressure of the refrigerant may be adjusted through an orifice or a narrow tube instead of the first valve 117 as described above. Even in this case, the refrigerant may be expanded so that the evaporation temperature of the refrigerant flowing into the rear heating unit 125 makes the outdoor temperature higher than the freezing point.

As a result, the post-heating unit 125 may continue to operate as an evaporator in the defrosting operation. Accordingly, even when the heat transfer unit 121 is defrosted through condensation, since the rear heat unit 125 continuously operates as an evaporator, heating can be continuously provided to the room.

The refrigerant evaporated through the post-heating unit 125 may flow into the fourth connecting pipe 114 through the post-heating pipe 153 , and may be recovered back to the compressor 100 along the suction pipes 141 and 142 .

On the other hand, when the evaporation temperature and the evaporation pressure of the back heat unit 125 are set to a temperature above the freezing point for defrosting the rear heat unit 125 , that is, the evaporation temperature and the evaporation pressure of the back heat unit 125 are the above-described heating If it rises from the case of operation, an additional heat of evaporation proportional to this is required.

To solve this, when an implantation occurs in the rear heat unit 125 , the hot gas valve 185 may be opened.

When the hot gas valve 185 is opened, the compressed refrigerant flowing through the discharge pipe 101 may be introduced into the bypass pipe 180 to be bypassed into the suction pipes 141 and 142 . Accordingly, the high-temperature, high-pressure refrigerant discharged from the compressor 100 may flow into the discharge side of the evaporator, that is, the suction side of the compressor 100 . (see arrow)

The compressed refrigerant has a relatively high enthalpy and high energy. Therefore, by bypassing the compressed refrigerant to the outlet side of the evaporator, there is an advantage in that it is possible to provide an additional amount of heat of evaporation by the evaporation temperature and evaporation pressure of the elevated back heat unit 125 .

That is, the additional heat of evaporation required for defrosting the post-heating unit 125 may be supplemented through the compressed refrigerant (high-temperature gas) introduced through the bypass pipe 180 .

On the other hand, in general, in a heating operation or a cooling operation, the operation of the compressor 100 may be driven by about 60% of the maximum operation capability. In general cooling and heating operation, when the compressor 100 operates at its maximum operating capacity, power consumption rises and the evaporation temperature decreases relatively rapidly due to excessive flow rate, so the amount of implantation of the evaporator rapidly increases. am. Accordingly, since it is difficult to perform defrosting as the amount of implantation increases, the operation capability of the compressor 100 is intentionally lowered from the maximum operation capability.

However, according to the embodiment of the present invention, the evaporation temperature of the back heat section 125 is raised to defrost the post heat section 125 and the insufficient amount of heat of evaporation is transferred to the outlet side of the evaporator. Compensate by bypassing.

In other words, since a part of the compressed refrigerant discharged from the compressor 100 is bypassed to the suction side of the compressor 100 as it is, it is a refrigerant that cannot perform a series of cycle cycles such as compression, condensation, expansion, and evaporation at all. consumed This may reduce the performance of the air conditioner due to a decrease in the flow rate of the refrigerant circulating in the cycle.

Accordingly, when an idea is generated in the rear heat unit 125 , the operating frequency of the compressor 100 may be increased in stages. Accordingly, it is possible to supplement the refrigerant flow rate bypassed by opening the hot gas valve 185, and to increase the refrigerant flow rate circulating the cycle, there is an advantage in that the performance of the air conditioner can be relatively improved.

6 is a diagram showing a P-H diagram of an air conditioner according to an embodiment of the present invention.

Referring to FIG. 6 , the cycle diagram (thin solid line) in the heating operation and the cycle diagram in the defrosting operation (thin one-dot chain line) may be compared.

Looking at the cycle diagram in the defrosting operation, it can be seen that the temperature and pressure for defrosting the heat transfer unit 121 are expanded by the first expansion device 131 . In addition, since the heat transfer unit 121 operates as a condenser to perform defrosting, it can be confirmed that the refrigerant is condensed.

In addition, the refrigerant expanded by the first valve 117 for defrosting the post-heating unit 125 may have an evaporation pressure and an evaporation temperature higher than those of the heating operation. Referring to the cycle diagram in the defrosting operation, it can be confirmed that the temperature of the surface of the after-heating part 125 is higher than the freezing point, and the evaporation pressure and the evaporation temperature are higher than those of the heating operation.

At this time, compared with the cycle diagram of the heating operation, it can be intuitively confirmed that an additional amount of heat of evaporation is required in the evaporation process.

In addition to this, the required amount of heat of evaporation may be supplemented by bypassing the compressed refrigerant discharged from the compressor 100 through the opening of the hot gas valve 185 to the outlet side of the evaporator as described above.

7 is a flowchart illustrating a control method for a defrosting operation of an air conditioner according to an embodiment of the present invention. Parts overlapping with the previously described parts will be omitted or briefly mentioned.

Referring to FIG. 7 , first, the controller 30 may determine whether a heating operation is performed. In the heating operation, the first expansion valve 131 and the second expansion valve 135 are in an open state to control the opening degree for the expansion of the refrigerant, and the hot gas valve 185 is in a closed state. (S1)

When it is determined that the heating operation is performed, the control unit 30 may determine whether the heat transfer unit 121 is implanted. For example, the control unit 30 may determine whether frost is formed on the heat transfer unit 121 based on the values detected by the outdoor temperature sensor and the first temperature sensor 122 during the heating operation (S2).

When frost is formed on the heat transfer unit 121 , the control unit 30 may enter a defrosting operation. In addition, if the implantation does not occur in the heat transfer unit 121 , the control unit 30 may determine whether the rear heat unit 125 is implanted ( S6 ).

When the heat transfer unit 121 is conceived, the second valve 165 and the second expansion valve 135 are closed, and the first valve 117 is opened. Accordingly, the refrigerant flowing into the heat transfer unit 121 may pass through the rear heat unit 125 in series. (S3)

In addition, the first expansion valve 131 can expand the condensed refrigerant only to a state of sufficient temperature and pressure to defrost the frost on the heat transfer unit 121 (refer to FIG. 6 ). The first expansion The refrigerant passing through the valve 131 may flow into the heat transfer unit 121 and defrost the heat transfer unit 121 through condensation. (S4)

In addition, the first valve 117 may expand the refrigerant that has passed through the heat transfer unit 121 to the inlet pressure of the rear heat unit 125 in the previous heating operation. That is, the refrigerant that has passed through the first valve 117 may be expanded to a low pressure and low temperature. Accordingly, the refrigerant flowing into the post-heating unit 125 may be evaporated in the same manner as in the above-described heating operation. This may be called the first valve 117 first adjustment step. (S5)

Thereafter, the control unit 30 may determine whether the rear heat unit 125 is implanted. For example, the control unit 30 may determine whether frost is formed in the rear heat unit 125 based on the detected values of the outdoor temperature sensor and the second temperature sensor 126 (S6).

When the back heat part 125 is conceived, the first valve 117 controls the evaporation pressure determined so that the temperature of the surface of the back heat part 125 is formed above the freezing point of the refrigerant passing through the heat transfer part 121 and It can expand to the evaporation temperature. In this case, the determined evaporation pressure and evaporation temperature are higher than the evaporation pressure and evaporation temperature of the rear heating unit 125 in the previous heating operation. This may be called the first valve 117 secondary control step. (S7)

In addition, the control unit 30 may control the hot gas valve 185 to be opened. According to this, since the high-energy compressed refrigerant discharged from the compressor 100 flows into the suction pipes 141 and 142 through the bypass pipe 180, it is possible to compensate for the amount of evaporation heat lacking due to the increase of the evaporation temperature (S8). )

In addition, the control unit 30 may control to increase the operating frequency of the compressor 100 in stages. Accordingly, it is possible to compensate for the insufficient flow rate of the circulating refrigerant due to the bypass of the compressed refrigerant through the bypass pipe 180 (S9).

Meanwhile, the control unit 30 may detect whether the temperature of the surface of the rear heating unit 125 satisfies the evaporation pressure and evaporation temperature set to form a freezing point or higher. For example, the control unit 30 may detect whether the evaporation temperature satisfies a set value (T) by the evaporation temperature sensing means (S10).

Furthermore, the control unit 30 may sense the evaporation temperature of the back heat unit 125 by means of an evaporation temperature sensing means, and may sense the outdoor air temperature around the back heat unit 125 by an outdoor temperature sensor. Accordingly, the control unit 30 may vary the evaporation temperature according to the environment for effective defrosting of the rear heat unit 125 based on the information sensed through the evaporation temperature sensing means and the outdoor temperature sensor.

Thereafter, the control unit 30 may determine whether the defrosting of the rear heating unit 125 has been completed. (S12)

When the defrosting of the heat transfer unit 121 and the rear heat unit 125 is completed, the previously switched valve may be returned to perform a heating operation. For example, the control unit 30 may control the operating frequency of the compressor 100 to return to the normal operating frequency, close the hot gas valve 185 and the first valve 117, and close the second valve ( 165) and the second expansion valve 135 may be controlled to be opened. And the control unit 30 may control the opening degree of the first expansion valve 131 to return to the same as the heating operation. (S13)

Thereafter, the defrosting operation of the outdoor heat exchanger 120 of the air conditioner is terminated, and the conventional heating operation may be continued (S14).

After all, in the defrosting operation, since the post-heating unit 125 can continuously operate as an evaporator, there is an advantage of providing continuous heating to the room. That is, when the conventional defrosting operation is performed, it is possible to solve the problem that the indoor temperature drops and the temperature rise time of the air becomes longer due to reheating.

In addition, during the defrosting process of the post-heating unit 125 described above, the amount of evaporation heat that is insufficient due to the rise of the evaporation pressure and the evaporation temperature can be supplemented through the opening and closing operation of the hot gas valve 185, and thus the decrease in the refrigerant flow rate is Since it can be offset by increasing the operating frequency of the compressor 100 , there is an effect of improving the performance of the air conditioner through defrosting of the outdoor heat exchanger 120 .

10: outdoor unit 20: indoor unit
100: compressor 120: outdoor heat exchanger
130: outdoor fan

Claims (17)

a compressor that compresses the refrigerant;
a discharge pipe connected to the discharge side of the compressor;
a suction pipe connected to the suction side of the compressor;
an outdoor heat exchanger provided with a heat transfer unit and a rear heat unit, the outdoor heat exchanger exchanging heat between the refrigerant and outdoor air;
a bypass pipe extending from the discharge pipe to the suction pipe; and
It includes a hot gas valve installed in the bypass pipe,
The hot gas valve is an air conditioner, characterized in that it is opened when the post-heating part is implanted.

The method of claim 1,
a temperature sensor for detecting whether the heat transfer unit and the rear heat unit are implanted; and
The air conditioner further comprising a control unit for performing control based on the detection result of the temperature sensor.

delete 3. The method of claim 2,
The hot gas valve is an air conditioner controlled by the control unit.

3. The method of claim 2,
The control unit, the air conditioner, characterized in that to increase the operating frequency of the compressor when the after-heating unit is conceived.

3. The method of claim 2,
a serial pipe connecting the outlet port of the heat transfer unit and the inlet port of the rear heat unit; and
The air conditioner further comprising a first valve installed in the series pipe.

7. The method of claim 6,
wherein the control unit adjusts the opening degree of the first valve so that an evaporation temperature of the back heat unit rises by a set temperature when the post heat unit is conceived.

8. The method of claim 7,
The set temperature is an air conditioner, characterized in that higher than the freezing point of the frost implanted.

The method of claim 1,
The suction pipe is
a first suction pipe for guiding the evaporated refrigerant to the accumulator; and
The air conditioner further comprising a second suction pipe extending from the accumulator to the suction side of the compressor.

The method of claim 1,
an indoor heat exchanger for exchanging the refrigerant and indoor air;
a connection pipe extending from the indoor heat exchanger to the inlet port of the heat transfer unit; and
The air conditioner further comprising a branch pipe branched from the connection pipe and extending to the inlet port of the rear heat part.

11. The method of claim 10,
The air conditioner further comprising an orifice installed in the branch pipe and capable of adjusting the evaporation pressure of the post-heating part.


The method of claim 1,
a flow conversion unit to which the discharge pipe and the suction pipe are connected, and to change the flow direction of the refrigerant;
a heat transfer pipe extending from the outlet port of the heat transfer unit to the flow conversion unit;
a back heat pipe branching from the heat transfer pipe and extending to an outlet port of the back heat part; and
The air conditioner further comprising a second valve installed on the heat transfer pipe.

An air conditioner comprising a compressor, an outdoor heat exchanger having a heat transfer unit and a rear heat unit, and an expansion valve, the air conditioner comprising:
determining whether the heat transfer unit is implanted;
opening a first valve installed in a series pipe connecting the outlet port of the heat transfer unit and the inlet port of the rear heat unit when the heat transfer unit is conceived;
determining whether the rear heating part is implanted;
expanding the pressure of the refrigerant passing through the first valve to a preset pressure when the post-heating unit is implanted; and
Comprising the step of bypassing the compressed refrigerant to the suction side of the compressor by a bypass pipe branched from the discharge side of the compressor,
The preset pressure is an air conditioner control method, characterized in that the pressure to increase the evaporation temperature of the after-heat unit.
14. The method of claim 13,
The evaporation temperature of the post-heating part, the air conditioner control method, characterized in that higher than the freezing point of the frost.
14. The method of claim 13,
The method of controlling the air conditioner further comprising the step of increasing the operating frequency of the compressor when the post-heating part is conceived.
14. The method of claim 13,
determining whether the defrosting of the electric heating unit and the rear heating unit has been completed; and
When the defrosting of the heating unit and the rear heating unit is completed, further comprising the step of returning to the heating operation,
The step of returning to the heating operation includes:
closing the hot gas valve installed in the first valve and the bypass pipe;
and opening a second valve installed at the outlet side of the heat transfer unit.
17. The method of claim 16,
In the heating operation, the refrigerant passing through the heat transfer unit and the rear heat unit flows in parallel.

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