WO2021167337A1

WO2021167337A1 - Air conditioner

Info

Publication number: WO2021167337A1
Application number: PCT/KR2021/002003
Authority: WO
Inventors: Hyungyul YUM; Eunjun Cho; Pilhyun Yoon
Original assignee: Lg Electronics Inc.
Priority date: 2020-02-17
Filing date: 2021-02-17
Publication date: 2021-08-26
Also published as: JP2023513827A; JP7460783B2; US20210254880A1; EP4107454A4; KR20210104476A; EP4107454A1; CN113266965A; DE102021201479A1

Abstract

The present disclosure relates to an air conditioner including: a defrosting bypass valve disposed at a defrosting bypass pipe having one end connected to a middle point of the outdoor heat exchanger, and the other end connected to an inlet pipe of a compressor, and a processor configured to open and close the defrosting bypass valve according to temperature of a refrigerant in an outdoor heat exchanger, in which at the beginning of a defrosting operation, the processor opens the defrosting bypass valve to bypass a portion of the refrigerant in the outdoor heat exchanger to the inlet pipe of the compressor, and if the temperature of the refrigerant in the outdoor heat exchanger exceeds a reference temperature, the processor closes the defrosting bypass valve, thereby achieving defrosting performance at the early stage of the defrosting operation.

Description

AIR CONDITIONER

The following description relates to an air conditioner, and more particularly to an air conditioner installed in a cold place.

Generally, an air conditioner is a device for cooling or heating indoor air by using a refrigeration cycle apparatus including a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger.

In the case of cooling the indoor air, the outdoor heat exchanger functions as a condenser, and the indoor heat exchanger functions as an evaporator, in which the refrigerant sequentially circulates through the compressor, the outdoor heat exchanger, the expansion device, the indoor heat exchanger, and the compressor.

In the case of heating the indoor air, the outdoor heat exchanger functions as an evaporator, and the indoor heat exchanger functions as a condenser, in which the refrigerant sequentially circulates through the compressor, the indoor heat exchanger, the expansion device, the outdoor heat exchanger, and the compressor.

In the case of heating the indoor air, a defrosting operation may be performed if necessary. For heating the indoor air, a refrigerant having a lower temperature than the outside air flows through the outdoor heat exchanger, and absorbs heat from the outside air. In this process, moisture contained in the outside air may be formed on the surface of the outdoor heat exchanger, and in a cold place, the moisture may be frozen on the surface of the outdoor heat exchanger. When the surface of the outdoor heat exchanger is frozen, a problem occurs in that heat exchange does not take place properly, thereby reducing heating efficiency. Accordingly, if necessary, it is required to perform a defrosting operation to remove the frozen ice.

Generally, during the defrosting operation, the refrigerant circulates in a reverse direction to a direction of a heating operation, and circulates in a similar direction to a circulation direction of the refrigerant during a cooling operation. However, the temperature of the refrigerant during the defrosting operation is always lower than the temperature of the refrigerant during the cooling operation, and the refrigerant flowing through an inlet pipe of the compressor has a very low temperature and very low pressure. Accordingly, a rotation speed (Hz) of the compressor is inevitably reduced, thereby resulting in poor defrosting performance.

Particularly, in commonly used air conditioners, various components are provided at a refrigerant passage to perform various operation modes. However, such air conditioners have a problem in that pressure loss increases as the refrigerant passes through the components. In addition, a combined cooling/heating air conditioner has a problem in that a refrigerant pipe installed at an outlet end of an outdoor heat exchanger is designed to have a small diameter to secure cooling performance, thereby increasing pressure loss and reducing defrosting performance.

It is an object of the present disclosure to provide an air conditioner, in which defrosting performance may be maintained by increasing pressure of a refrigerant in a compressor inlet pipe at an early stage of a defrosting operation.

It is another object of the present disclosure to provide an air conditioner capable of rapidly defrosting the ice frozen on an outdoor heat exchanger by minimizing pressure loss caused when the refrigerant flows.

The objects of the present disclosure are not limited to the aforementioned objects, and other objects not described herein will be clearly understood by those skilled in the art from the following description.

In accordance with an aspect of the present disclosure, the above and other objects can be accomplished by providing an air conditioner including: a compressor configured to compress a refrigerant; an indoor heat exchanger disposed at a pipe connected to the compressor, and configured to perform heat exchange between the refrigerant and indoor air; an outdoor heat exchanger disposed at a pipe which is connected to the compressor and which is different from the pipe where the indoor heat exchanger is disposed, and configured to perform heat exchange between the refrigerant and outside air; and an expansion device disposed at a pipe connecting the indoor heat exchanger and the outdoor heat exchanger, and configured to expand the refrigerant. The air conditioner also includes: a defrosting bypass pipe having one end connected to a middle point of the outdoor heat exchanger, and the other end connected to an inlet pipe of the compressor; a defrosting bypass valve disposed at the defrosting bypass pipe; and a processor configured to open and close the defrosting bypass valve according to temperature of the refrigerant flowing into the compressor through an inlet pipe of the compressor.

Further, in accordance with another aspect of the present disclosure, the above and other objects can be accomplished by providing an air conditioner including: a compressor configured to compress a refrigerant; an indoor heat exchanger disposed at a pipe connected to the compressor, and configured to perform heat exchange between the refrigerant and indoor air; an outdoor heat exchanger disposed at a pipe which is connected to the compressor and which is different from the pipe where the indoor heat exchanger is disposed, and configured to perform heat exchange between the refrigerant and outside air; an expansion device disposed at a pipe connecting the indoor heat exchanger and the outdoor heat exchanger, and configured to expand the refrigerant. The air conditioner also includes: a defrosting bypass pipe having one end connected to a middle point of the outdoor heat exchanger, and the other end connected to an inlet pipe of the compressor; and a defrosting bypass valve disposed at the defrosting bypass pipe.

The outdoor heat exchanger may include: a first row in which a tube connected to the pipe connected to the compressor is disposed; a third row in which a tube connected to a pipe connected to the expansion device is disposed; and a second row, which is disposed between the first row and the third row and in which a tube connecting the tube in the first row and the tube in the third row is disposed, wherein the defrosting bypass pipe may be connected to the tube disposed in the second row.

In the outdoor heat exchanger, a flow direction of the refrigerant in the first row may be opposite to a flow direction of the refrigerant in the second row.

In the outdoor heat exchanger, a lower end of the second row may communicate with the first row, and an upper end of the second row may communicate with the third row.

In response to temperature of the refrigerant in the outdoor heat exchanger being lower than a predetermined temperature, the processor may open the defrosting bypass valve, and in response to temperature of the refrigerant in the outdoor heat exchanger being higher than or equal to the predetermined temperature, the processor may close the defrosting bypass valve.

The air conditioner may further include an accumulator disposed between the indoor heat exchanger and the compressor. In this case, the defrosting bypass pipe may include: a common bypass pipe connected to the outdoor heat exchanger; a first bypass pipe branched from the common bypass pipe and connected to the inlet pipe of the compressor; and a second bypass pipe branched from the common bypass pipe and connected to an inlet pipe of the accumulator.

The defrosting bypass valve may include: a first bypass valve disposed on the first bypass pipe; and a second bypass valve disposed on the second bypass pipe.

According to the temperature of the refrigerant in the outdoor heat exchanger, the processor may selectively open and close the first bypass valve or the second bypass valve.

In response to the temperature of the refrigerant in the outdoor heat exchanger being lower than the predetermined reference temperature, the processor may open the second bypass valve, and in response to the temperature of the refrigerant in the outdoor heat exchanger being higher than or equal to the predetermined reference temperature, the processor may close the second bypass valve.

In accordance with yet another aspect of the present disclosure, the above and other objects can be accomplished by providing a method of controlling an air conditioner including a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger, the method including: performing a high-speed defrosting operation of opening a defrosting bypass valve disposed at a defrosting bypass pipe having one end connected to a middle point of the outdoor heat exchanger, and the other end connected to an inlet pipe of the compressor; and in response to temperature of a refrigerant in the outdoor heat exchanger being higher than or equal to a reference temperature, performing a normal defrosting operation of closing the defrosting bypass valve.

The defrosting bypass pipe may include: a common bypass pipe connected to the outdoor heat exchanger; a first bypass pipe branched from the common bypass pipe and connected to the inlet pipe of the compressor; and a second bypass pipe branched from the common bypass pipe and connected to an inlet pipe of the accumulator, wherein the performing of the high-speed defrosting operation may include selectively opening and closing the first bypass valve disposed on the first bypass pipe or the second bypass valve disposed on the second bypass pipe according to the temperature of the refrigerant in the outdoor heat exchanger.

The performing of the high-speed defrosting operation may include, in response to the temperature of the refrigerant in the outdoor heat exchanger being lower than the predetermined reference temperature, opening the second bypass valve, and in response to the temperature of the refrigerant in the outdoor heat exchanger being higher than or equal to the predetermined reference temperature, closing the second bypass valve.

Other detailed matters of the exemplary embodiments are included in the detailed description and the drawings.

The air conditioner according to the present disclosure has one or more of the following effects.

First, a portion of the refrigerant is branched from the middle of the outdoor heat exchanger at an early stage of the defrosting operation and is bypassed to the compressor inlet pipe, such that pressure of the refrigerant flowing into the compressor through the compressor inlet pipe at the early stage of the defrosting operation may be secured, thereby maintaining defrosting performance.

Second, a portion of the refrigerant is branched from the middle of the outdoor heat exchanger, and is bypassed directly to the compressor inlet pipe without passing through other components, such that pressure loss of the refrigerant may be minimized.

Third, according to a second embodiment, a portion of the refrigerant, branched from a common bypass valve, is bypassed to an inlet pipe of an accumulator, so that a condensed refrigerant, present in the branched portion of the refrigerant, may be separated at the accumulator, and only a vaporized refrigerant may be guided to the compressor, thereby achieving defrosting performance.

The effects of the present disclosure are not limited to the aforesaid, and other effects not described herein will be clearly understood by those skilled in the art from the following description of the appended claims.

Figure 1 is a diagram illustrating an air conditioner during a heating operation according to a first embodiment of the present disclosure;

Figure 2 is a diagram illustrating the air conditioner of Figure 1 during a cooling operation;

Figure 3 is a diagram illustrating the air conditioner of Figure 1 during a defrosting operation;

Figure 4 is a control block diagram illustrating the air conditioner of Figure 1;

Figure 5 is a diagram illustrating an air conditioner during a defrosting operation according to a second embodiment of the present disclosure; and

Figure 6 is a control block diagram illustrating the air conditioner of Figure 5.

Advantages and features of the present disclosure and methods for accomplishing the same will be more clearly understood from exemplary embodiments described below with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiments but may be implemented in various different forms. The embodiments are provided only to complete disclosure of the present disclosure and to fully provide a person having ordinary skill in the art to which the present disclosure pertains with the category of the present disclosure, and the present disclosure will be defined by the scope of the appended claims. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings to explain an air conditioner.

Figure 1 is a diagram illustrating an air conditioner according to an embodiment of the present disclosure.

Referring to Figure 1, the air conditioner according to an embodiment of the present disclosure may include a compressor 1, an outdoor heat exchanger 2, an expansion device 3, and an indoor heat exchanger 4.

The compressor 1, the outdoor heat exchanger 2, the expansion device 3, and the indoor heat exchanger 4 may be connected by refrigerant pipes.

The compressor 1, the outdoor heat exchanger 2, and the expansion device 3 may form an outdoor unit. The outdoor unit may include an outdoor blower (not shown) for blowing air to the outdoor heat exchanger 2. By rotation of the outdoor blower, outside air may be introduced into the outdoor unit, to be heat exchanged with the outdoor heat exchanger 2 and then to be discharged to the outside.

The indoor heat exchanger 4 may be included in an indoor unit. The indoor unit may further an indoor blower (not shown) for blowing air to the indoor heat exchanger 4. By rotation of the indoor blower, indoor air may be introduced into the indoor unit, to be heat exchanged with the indoor heat exchanger 4 and then to be discharged indoors.

During a cooling operation of the air conditioner, the outdoor heat exchanger 2 may function as a condenser, and the indoor heat exchanger 4 may function as an evaporator. During the cooling operation of the air conditioner, the refrigerant may sequentially circulate through the compressor 1, the outdoor heat exchanger 2, the expansion device 3, the indoor heat exchanger 4, and the compressor 1.

During a heating operation of the air conditioner, the outdoor heat exchanger 2 may function as an evaporator, and the indoor heat exchanger 4 may function as a condenser. During the heating operation of the air conditioner, the refrigerant may sequentially circulate through the compressor 1, the indoor heat exchanger 4, the expansion device 3, the outdoor heat exchanger 2, and the compressor 1.

The compressor 1 may compress the refrigerant. The condenser may condense the refrigerant having passed through the compressor 1. The expansion device 3 may expand the refrigerant having passed through the condenser. The evaporator may evaporate the refrigerant having passed through the expansion device 3.

The air conditioner may be an air conditioner capable of both the cooling operation and the heating operation. However, the air conditioner may also be provided as an air conditioner capable of only the heating operation.

The following description will be given using an example in which the air conditioner is capable of both the cooling operation and the heating operation.

The air conditioner according to an embodiment of the present disclosure may further include a cooling/heating switching valve 7. The cooling/heating switching valve 7 may be included in the outdoor unit. The cooling/heating switching valve 7 may switch a flow direction of the refrigerant, discharged from the compressor 1, to either the outdoor heat exchanger 2 or the indoor heat exchanger 4.

Compressor intake passages

81, 8, and 85 may connect an outlet of the outdoor heat exchanger 2 during the heating operation and an inlet of the compressor 1. The

compressor intake passages

81, 8, and 85 may include: an accumulator 8 separating liquid refrigerant from gaseous refrigerant; a first refrigerant pipe 81 connecting an outlet of the outdoor heat exchanger 2 during the heating operation and an inlet of the accumulator 8; and a compressor inlet pipe 85 connecting an outlet of the accumulator 8 and the inlet of the compressor 1.

During the heating operation of the air conditioner, the liquid refrigerant and the gaseous refrigerant may flow to the accumulator 8 from the outdoor heat exchanger 2 through the first refrigerant pipe 81; and the refrigerant, flowing to the accumulator 8, may be separated into the liquid refrigerant and the gaseous refrigerant.

The liquid refrigerant, separated at the accumulator 8, may be accommodated in a lower part of the accumulator 8, and the gaseous refrigerant separated at the accumulator 8 may be placed above the separated liquid refrigerant.

The gaseous refrigerant, separated at the accumulator 8, may flow into the compressor 1 through the compressor inlet pipe 85, and the liquid refrigerant separated at the accumulator 8, may remain as it is in the accumulator 8.

A second refrigerant pipe 82 may connect an outlet of the indoor heat exchanger 82 during the heating operation and an inlet of the expansion device 3 during the heating operation.

A third refrigerant pipe 83 may connect an outlet of the expansion device 3 during the heating operation and the inlet of the outdoor heat exchanger 2 during the heating operation.

A fourth refrigerant pipe 84 may connect the outlet of the compressor 1 and the inlet of the indoor heat exchanger 4 during the heating operation.

The cooling/heating switching valve 7 may be installed at the first refrigerant pipe 81 and the fourth refrigerant pipe 84.

The outdoor heat exchanger 2 may be a fin-tube type heat exchanger. The outdoor heat exchanger 2 is formed with a plurality of fins being arranged one above the other, and tubes passing through the fins several times. A refrigerant passage, through which the refrigerant circulates, may be formed in the tubes.

Referring to Figure 1, the outdoor heat exchanger 2 may include the refrigerant passage divided into a plurality of unit passages. In this embodiment, the refrigerant passage is divided into three unit passages, but the present disclosure is not limited thereto, and may also be divided into four or more or two or less unit passages. In this embodiment, the refrigerant passage of the outdoor heat exchanger 2 is divided into upper, middle, and lower passages.

Referring to Figure 1, the refrigerant passage of the outdoor heat exchanger 2 may be formed of a plurality of rows on the side part thereof. In this embodiment, three rows are formed, but the present disclosure is not limited thereto, and three or more rows may be formed, as is known to those skilled in the art.

The outdoor heat exchanger 2 may include a first row 21 connected to the first refrigerant pipe 81 connected to the compressor 1. The outdoor heat exchanger 2 may include a third row 23 connected to the third refrigerant pipe 83 connected to the expansion device 3. The outdoor heat exchanger 2 may include a second row 22 disposed between the first row 21 and the third row 23.

A tube disposed in the first row 21 has one side connected to the first refrigerant pipe 81 connected to the compressor 1, and the other side connected to a tube disposed in the second row 22. A tube disposed in the second row 22 has one side connected to the tube in the first row 21, and the other side connected to a tube in the third row 23. The tube disposed in the third row 23 has one side connected to the tube in the second row 22, and the other side connected to the second refrigerant pipe 82 connected to the expansion device 3.

The first refrigerant pipe 81 may be connected to the tube disposed at an upper side of the first row 21. In the first row 21, the refrigerant may flow from the upper side to the lower side. The tube in the second row 22 and the tube in the first row 21 may communicate with each other at a lower end. In the second row 22, the refrigerant may flow from the lower side to the upper side. The tube in the third row 23 and the tube in the second row 22 may communicate with each other at an upper end. In the third row 23, the refrigerant may flow from the upper side to the lower side. The third refrigerant pipe 83 may be connected to the tube disposed at a lower side of the third row 23.

A flow direction of the refrigerant in the first row 21 may be opposite to a flow direction of the refrigerant in the second row 22. The flow direction of the refrigerant in the second row 22 may be opposite to a flow direction of the refrigerant in the third row 23. For example, if a flow direction of the refrigerant in the first row 21 is a downward direction, a flow direction of the refrigerant in the second row 22 may be an upward direction, and a flow direction of the refrigerant in the third row 23 may be a downward direction.

At least one or more temperature sensors may be disposed in the outdoor heat exchanger 2. Referring to Figure 1, the outdoor heat exchanger 2 may include a first outdoor heat exchanger temperature sensor 221 and a second outdoor heat exchanger temperature sensor 231. In the present disclosure, temperature T_HEX of the outdoor heat exchanger 2, which is controlled by a processor, may be temperature measured by the first outdoor heat exchanger temperature sensor 221.

The first outdoor heat exchanger temperature sensor 221 may be disposed in the second row 22. The first outdoor heat exchanger temperature sensor 221 may be disposed in the outdoor heat exchanger 2 at a position adjacent to a defrosting bypass pipe 86. According to a second embodiment which will be described later, the first outdoor heat exchanger temperature sensor 221 may be disposed in the outdoor heat exchanger 2 at a position adjacent to a common bypass pipe 86c. The first outdoor heat exchanger temperature sensor 221 may be disposed at a connection point between the common bypass pipe 86c and the outdoor heat exchanger 2.

The first outdoor heat exchanger temperature sensor 221 may measure temperature of the refrigerant bypassed from the outdoor heat exchanger 2 to a bypass pipe 86, and may transmit the measured data to the processor 300.

The second outdoor heat exchanger temperature sensor 231 may be disposed in the third row 23. The second outdoor heat exchanger temperature sensor 231 may be disposed in the outdoor heat exchanger 2 at a position adjacent to the third refrigerant pipe 83. The second outdoor heat exchanger temperature sensor 231 may be disposed at a connection point between the third refrigerant pipe 83 and the outdoor heat exchanger 2.

The second outdoor heat exchanger temperature sensor 231 may measure temperature of the refrigerant discharged from the outdoor heat exchanger 2 to the third refrigerant pipe 83, and may transmit the measured data to the processor 300.

Although not illustrated herein, when the refrigerant passage of the outdoor heat exchanger 2 is divided into upper, middle, and lower passages as illustrated in Figure 1, the first temperature sensor 221 and the second temperature sensor 231 may be disposed at a position corresponding to the middle refrigerant passage and may be disposed at a position corresponding to the lower refrigerant passage.

The defrosting bypass pipe 86 has one end connected to the outdoor heat exchanger 2 and the other end connected to the inlet pipe 85 of the compressor 1. The defrosting bypass pipe 86 is a device for bypassing a portion of the refrigerant, flowing through the outdoor heat exchanger 2, to the compressor 1.

One end of the defrosting bypass pipe 86 is connected to the outdoor heat exchanger 2, and the refrigerant flows therethrough. The defrosting bypass pipe 86 may be connected to the tube in the second row 22 of the outdoor heat exchanger 2. When the refrigerant passage of the outdoor heat exchanger 2 is divided into upper, middle, and lower passages as illustrated in Figure 1, the defrosting bypass pipe 86 may be connected in parallel to each of the upper, middle, and lower tubes.

The defrosting bypass pipe 86 may be connected to the middle of the tube in the second row 22 of the outdoor heat exchanger 2. The defrosting bypass pipe 86 is desirably connected at the center of the tube of the second row 22, but as illustrated in Figure 1, the defrosting bypass pipe 86 may be connected at a position as close to the center of the tube of the second row 22 as possible.

The other end of the defrosting bypass pipe 86 is connected to the inlet pipe 85 of the compressor 1. The defrosting bypass pipe 86 is connected to the inlet pipe 85 of the compressor 1 to allow the bypassed refrigerant to flow into the compressor 1.

The defrosting bypass pipe 86 has effects in that by bypassing a portion of the refrigerant to the compressor 1, it is possible to prevent pressure of the refrigerant flowing into the compressor 1 from dropping to a level lower than a threshold, and by increasing temperature of the refrigerant falling into the compressor 1 to a sufficient level, defrosting performance may be improved.

A defrosting bypass valve 87 is disposed at the defrosting bypass pipe 86 and is a device for opening and closing the defrosting bypass pipe 86. The defrosting bypass valve 87 may open the defrosting bypass pipe 86 during the heating operation of the air conditioner, and may close the defrosting bypass pipe 86 during the cooling operation hereof. The defrosting bypass valve 87 may be an opening/closing valve, and may control an amount of the refrigerant flowing through the defrosting bypass pipe 86.

The processor 300 is a device for controlling the operation of the air conditioner. The processor 300 may be disposed in the air conditioner.

The processor 300 may perform controlling operations, such as controlling the operation of the compressor 1, controlling the opening and closing of the expansion device 3, controlling opening and closing an air outlet of the air conditioner or changing a discharge angle thereof, and the like. Further, in addition to the controlling operations, the processor 300 may perform a control method which can be easily adopted by those skilled in the art.

The processor 300 may control the defrosting bypass valve 87. By opening or closing the defrosting bypass valve 87 disposed at the defrosting bypass pipe 86, the processor 300 may bypass the refrigerant to the inlet pipe 85 of the compressor 1. By opening the defrosting bypass valve 87 for a predetermined period of time, the processor 300 may bypass the refrigerant to the inlet pipe 85 of the compressor 1; and after the predetermined period of time elapses, the processor 300 may close the defrosting bypass valve 87 so as not to bypass the refrigerant.

The predetermined period of time is a time corresponding to pressure of the refrigerant introduced into the compressor 1, at which the refrigerant is sufficient to maintain defrosting performance. During the predetermined period of time, the processor 300 may open the defrosting bypass valve 87 and bypass the refrigerant to compensate for the pressure of the refrigerant introduced into the compressor 1. After the predetermined period of time elapses, the processor 300 may close the defrosting bypass valve 87 so as not to bypass the refrigerant. The processor 300 may calculate the predetermined period of time according to temperature of the outdoor heat exchanger 2.

If temperature of the refrigerant in the outdoor heat exchanger 2 is less than a predetermined reference temperature, the processor 300 may open the defrosting bypass valve 87; and if temperature of the refrigerant in the outdoor heat exchanger 2 is higher than or equal to the predetermined reference temperature, the processor 30 may close the defrosting bypass valve 87. The reference temperature is already stored in the processor 300, and may be determined through experiments. The reference temperature is a temperature of the refrigerant in the outdoor heat exchanger 2, which corresponds to the pressure of the refrigerant at which the refrigerant introduced into the compressor 1 is sufficient to achieve defrosting performance although the refrigerant is not bypassed. That is, if temperature of the refrigerant passing through the outdoor heat exchanger 2, is higher than or equal to the reference temperature, even when the refrigerant is not bypassed to the inlet pipe 85 of the compressor 1, the refrigerant introduced into the compressor 1 has a sufficiently high pressure to achieve required defrosting performance.

For example, upon starting a high-speed defrosting operation, the processor 300 may close the defrosting bypass valve 87 when temperature of the refrigerant, bypassed from the outdoor heat exchanger 2, reaches 12Е. When the temperature of the refrigerant is 12Е, pressure of the refrigerant introduced into the compressor 1 is sufficient to achieve defrosting performance even when the refrigerant is not bypassed.

The following description will be given of a flow of the refrigerant during the heating operation of the air conditioner. The refrigerant, compressed by the compressor 1, flows to the cooling/heating switching valve 7 through a front portion of the fourth refrigerant pipe 84. The refrigerant, flowing to the cooling/heating switching valve 7, flows to the indoor heat exchanger 4 through a rear portion of the fourth refrigerant pipe 84. After flowing to the indoor heat exchanger 4, the refrigerant flows to the expansion device 3 through the second refrigerant pipe 82. The refrigerant flowing to the expansion device 3 flows to the outdoor heat exchanger 2 through the third refrigerant pipe 83. After flowing to the outdoor heat exchanger 2, the refrigerant flows to the cooling/heating switching valve 7 through a front portion of the first refrigerant pipe 81. After flowing to the cooling/heating switching valve 7, the refrigerant flows to the accumulator 8 through a rear portion of the first refrigerant pipe 81. After flowing to the accumulator 8, the refrigerant flows to the compressor 1 through the compressor inlet pipe 85. During the heating operation of the air conditioner, the flow of the refrigerant is repeated in this manner.

The following description will be given of a flow of a refrigerant during a cooling operation of the air conditioner. The refrigerant, compressed by the compressor 1, flows to the cooling/heating switching valve 7 through a front portion of the fourth refrigerant pipe 84. After flowing to the cooling/heating switching valve 7, the refrigerant flows to the outdoor heat exchanger 2 through the front portion of the first refrigerant pipe 81. After flowing the outdoor heat exchanger 2, the refrigerant flows to the expansion device 3 through the second refrigerant pipe 82. After flowing to the expansion device 3, the refrigerant flows to the indoor heat exchanger 4 through the second refrigerant pipe 82. After flowing to the indoor heat exchanger 4, the refrigerant flows to the cooling/heating switching valve 7 through a rear portion of the fourth refrigerant pipe 84. After flowing to the cooling/heating switching valve 7, the refrigerant flows to the accumulator 8 through the rear portion of the first refrigerant pipe 81. After flowing to the accumulator 8, the refrigerant flows to the compressor 1 through the compressor inlet pipe 85. During the cooling operation of the air conditioner, the flow of refrigerant is repeated in this manner.

The following description will be given of a flow of a refrigerant during a normal defrosting operation of the air conditioner. The refrigerant, compressed by the compressor 1, flows to the cooling/heating switching valve 7 through the front portion of the fourth refrigerant pipe 84. After flowing to the cooling/heating switching valve 7, the refrigerant flows to the outdoor heat exchanger 2 through the front portion of the first refrigerant pipe 81, and removes moisture or ice formed on the outdoor heat exchanger 2. After flowing to the outdoor heat exchanger 2, the refrigerant flows to the expansion device 3 through the second refrigerant pipe 82. After flowing to the expansion device 3, the refrigerant flows to the indoor heat exchanger 4 through the second refrigerant pipe 82. After flowing to the indoor heat exchanger 4, the refrigerant flows to the cooling/heating switching valve 7 through a rear portion of the fourth refrigerant pipe 84. After flowing to the cooling/heating switching valve 7, the refrigerant flows to the accumulator 8 through the rear portion of the first refrigerant pipe 81. After flowing to the accumulator 8, the refrigerant flows to the compressor 1 through the compressor inlet pipe 85. During the normal defrosting operation of the air conditioner, the flow of refrigerant is repeated in this manner.

In the normal defrosting operation of the air conditioner, a high-speed defrosting operation may be partially included. A time for the high-speed defrosting operation is controlled by the processor 300. When starting the normal defrosting operation, the processor 300 may include some of the high-speed defrosting operation. Upon starting the normal defrosting operation, the processor 300 starts the high-speed defrosting operation, and after a lapse of a predetermined period of time, the processor 300 may terminate the high-speed defrosting operation and may start the normal defrosting operation.

The following description will be given of a flow of the refrigerant during the high-speed defrosting operation of the air conditioner. The refrigerant, compressed by the compressor 1, flows to the cooling/heating switching valve 7 through the front portion of the fourth refrigerant pipe 84. After flowing to the cooling/heating switching valve 7, the refrigerant flows to the outdoor heat exchanger 2 through the front portion of the first refrigerant pipe 81. A portion of the refrigerant flowing to the outdoor heat exchanger 2 flows through the bypass pipe 86 connected to the second row 22, and the remaining refrigerant passes through the third row 23 to flow through the second refrigerant pipe 82.

The portion of the refrigerant flowing through the bypass pipe 86 is joined with the remaining refrigerant at the inlet pipe 85 of the compressor 1 to flow into the compressor 1. The remaining refrigerant flows into the compressor 1 by passing through the expansion device and the like in the same manner as the normal defrosting operation, and is joined with the portion of the refrigerant at the inlet pipe 85 of the compressor 1. During the high-speed defrosting operation of the air conditioner, the flow of the refrigerant is repeated in this manner.

In the high-speed defrosting operation, a portion of the refrigerant is branched while flowing through the outdoor heat exchanger 2, to be bypassed to the inlet pipe 85 of the compressor 1. Pressure of the remaining refrigerant drops while the refrigerant passes through the expansion device 3, and while the refrigerant passes through other components, pressure loss increases such that the pressure of the refrigerant flowing into the compressor 1 further drops. Accordingly, the pressure of the refrigerant at the inlet pipe 85 of the compressor 1 is too low to provide defrosting performance properly. In this case, the bypassed portion of the refrigerant is joined to compensate for the pressure drop, thereby producing an effect of providing defrosting performance of the air conditioner.

Furthermore, in order to achieve defrosting performance, the third refrigerant pipe 83, connected to an outlet end of the outdoor heat exchanger 2, is required to have a sufficiently large diameter, but if the third refrigerant pipe 83 is large, there is a problem in that cooling performance is greatly reduced. Accordingly, by performing the high-speed defrosting operation before the normal defrosting operation, defrosting performance may be provided at an early stage of the defrosting operation even when the third refrigerant pipe 83 has a sufficiently small diameter, and the cooling performance may also be maintained.

In this case, however, only a portion of the refrigerant flows in the outdoor heat exchanger 2 but the remaining refrigerant does not flow therein, such that a problem occurs in that normal operation performance is reduced. Further, in the outdoor heat exchanger 2, a portion of the refrigerant does not flow through the tube of the third row 23 and a portion of the tube of the second row 22, such that defrosting may not be performed properly. Accordingly, by terminating the high-speed defrosting operation at a proper time and switching the defrosting operation to the normal defrosting operation, the processor 300 may provide general defrosting operation performance. Here, the proper time may be a time when temperature of the heat exchanger is higher than or equal to a reference temperature, and may be a time when the pressure of the refrigerant at the inlet pipe 85 of the compressor 1 is sufficient to properly provide defrosting performance.

Figure 5 is a diagram illustrating an air conditioner according to a second embodiment of the present disclosure. Here, in the second embodiment, the same parts as those of the first embodiment will be denoted by the same reference numerals and a detailed description thereof will be omitted, and the following description will be focused on different points.

Referring to Figure 5, the defrosting bypass pipe 86 may be connected to the middle of the outdoor heat exchanger 2. More specifically, the common bypass pipe 86c of the defrosting bypass pipe 86 may be connected to the middle of the outdoor heat exchanger 2. One end of the common bypass pipe 86c may be branched into at least two pipes and the branched pipes may be referred to as a first bypass pipe 86a and a second bypass pipe 86b.

The first bypass pipe 86a is branched from the common bypass pipe 86c, and may be connected to the inlet pipe 85 of the compressor 1. That is, the first bypass pipe 86a may be connected to the inlet pipe 85 of the compressor 1 as in the first embodiment. A first bypass valve 87a may be disposed on the first bypass pipe 86a.

The second bypass pipe 86b is branched from the common bypass pipe 86c, and may be connected to an inlet pipe of the accumulator 8. A portion of the refrigerant branched from the common bypass pipe 86c may pass through the second bypass pipe 86b to flow into the inlet pipe of the accumulator 8.

After passing through the second bypass pipe 86b, the portion of the refrigerant flows into the accumulator 8 to be separated into a liquid refrigerant and a gaseous refrigerant. The gaseous refrigerant separated at the accumulator 8 flows into the compressor 1 through the inlet pipe of the compressor 1; and the liquid refrigerant separated at the accumulator 8 may remain as it is in the accumulator 8.

During the normal defrosting operation of the air conditioner, the processor 300 may perform a portion of the high-speed defrosting operation, which is similar to the control method of the first embodiment.

However, unlike the first embodiment, the processor 300 may selectively open and close the first bypass valve 87a and the second bypass valve 87b.

More specifically, in the second embodiment, unlike the first embodiment, if the temperature of the refrigerant in the outdoor heat exchanger 2 is lower than a predetermined reference temperature, the processor 300 may open the second bypass valve 87b, and if the temperature of the refrigerant is higher than or equal to the predetermined reference temperature, the processor 300 may close the second bypass valve 87b.

By opening the second bypass valve 87b, the processor 300 may guide the bypassed refrigerant to the inlet pipe of the accumulator 8. The refrigerant bypassed to the inlet pipe of the accumulator 8 may be mixed with the refrigerant having passed through the indoor heat exchanger 4, and may flow into the accumulator 8. The refrigerant flowing into the accumulator 8 may be separated into a liquid refrigerant and a gaseous refrigerant. The gaseous refrigerant separated at the accumulator 8 may pass through the compressor inlet pipe to flow into the compressor 1, and the liquid refrigerant separated at the accumulator 8 may remain as it is in the accumulator 8.

As described above, the air conditioner according to the embodiments of the present disclosure have an effect of maintaining defrosting performance by preventing abnormal pressure drop occurring at the inlet pipe 85 of the compressor 1 at the early stage of the defrosting operation when the refrigerant, branched from the middle of the outdoor heat exchanger 2, is bypassed to the inlet pipe 85 of the compressor 1. In addition, as a portion of the refrigerant is bypassed directly to the compressor 1 without circulating through other components of the air conditioner, the air conditioner also has an effect of improving defrosting performance at the early stage of the defrosting operation. Furthermore, in the air conditioner, by further reducing pressure loss of the refrigerant flowing to a rear end of the outdoor heat exchanger 2, the third refrigerant pipe 83 having a relatively small diameter may be designed to have a much smaller diameter, thereby producing an effect of improving cooling performance.

While the present disclosure has been shown and described with reference to the preferred embodiments thereof, it should be understood that the present disclosure is not limited to the aforementioned specific embodiments, and various modifications and variations may be made by those skilled in the art without departing from the scope and spirit of the invention as defined by the appended claims, and the modified implementations should not be construed independently of the technical idea or prospect of the present disclosure.

Claims

An air conditioner comprising:

a compressor configured to compress a refrigerant;

an indoor heat exchanger disposed at a pipe connected to the compressor, and configured to perform heat exchange between the refrigerant and indoor air;

an outdoor heat exchanger disposed at a pipe which is connected to the compressor and at which the indoor heat exchanger is not disposed, and configured to perform heat exchange between the refrigerant and outside air;

an expansion device disposed at a pipe connecting the indoor heat exchanger and the outdoor heat exchanger, and configured to expand the refrigerant;

a defrosting bypass pipe having one end connected to a middle point of the outdoor heat exchanger, and the other end connected to an inlet pipe of the compressor;

a defrosting bypass valve disposed at the defrosting bypass pipe; and

a processor configured to open and close the defrosting bypass valve according to temperature of the refrigerant in the outdoor heat exchanger.
The air conditioner of claim 1, wherein the outdoor heat exchanger comprises:

a first row in which a tube connected to the pipe connected to the compressor is disposed;

a third row in which a tube connected to a pipe connected to the expansion device is disposed; and

a second row, which is disposed between the first row and the third row and in which a tube connecting the tube in the first row and the tube in the third row is disposed,

wherein the defrosting bypass pipe is connected to the tube disposed in the second row.
The air conditioner of claim 2, wherein in the outdoor heat exchanger, a flow direction of the refrigerant in the first row is opposite to a flow direction of the refrigerant in the second row.
The air conditioner of claim 2, wherein in the outdoor heat exchanger, a lower end of the second row communicates with the first row, and an upper end of the second row communicates with the third row.
The air conditioner of claim 1, wherein in response to temperature of the refrigerant in the outdoor heat exchanger being lower than a predetermined temperature, the processor opens the defrosting bypass valve, and in response to temperature of the refrigerant in the outdoor heat exchanger being higher than or equal to the predetermined temperature, the processor closes the defrosting bypass valve.
The air conditioner of claim 1, further comprising an accumulator disposed between the indoor heat exchanger and the compressor,

wherein the defrosting bypass pipe comprises:

a common bypass pipe connected to the outdoor heat exchanger;

a first bypass pipe branched from the common bypass pipe and connected to the inlet pipe of the compressor; and

a second bypass pipe branched from the common bypass pipe and connected to an inlet pipe of the accumulator.
The air conditioner of claim 6, wherein the defrosting bypass valve comprises:

a first bypass valve disposed on the first bypass pipe; and

a second bypass valve disposed on the second bypass pipe.
The air conditioner of claim 7, wherein according to the temperature of the refrigerant in the outdoor heat exchanger, the processor selectively opens and closes the first bypass valve or the second bypass valve.
The air conditioner of claim 7, wherein in response to the temperature of the refrigerant in the outdoor heat exchanger being lower than a predetermined reference temperature, the processor opens the second bypass valve, and in response to the temperature of the refrigerant in the outdoor heat exchanger being higher than or equal to the predetermined reference temperature, the processor closes the second bypass valve.
A method of controlling an air conditioner comprising a compressor, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger, the method comprising:

performing a high-speed defrosting operation of opening a defrosting bypass valve disposed at a defrosting bypass pipe having one end connected to a middle point of the outdoor heat exchanger, and the other end connected to an inlet pipe of the compressor; and

in response to temperature of a refrigerant in the outdoor heat exchanger being higher than or equal to a reference temperature, performing a normal defrosting operation of closing the defrosting bypass valve.
The method of claim 10, wherein the defrosting bypass pipe comprises:

a common bypass pipe connected to the outdoor heat exchanger;

a first bypass pipe branched from the common bypass pipe and connected to the inlet pipe of the compressor; and

a second bypass pipe branched from the common bypass pipe and connected to an inlet pipe of the accumulator,

wherein the performing of the high-speed defrosting operation comprises selectively opening and closing the first bypass valve or the second bypass valve according to the temperature of the refrigerant in the outdoor heat exchanger.
The method of claim 11, wherein the performing of the high-speed defrosting operation comprises, in response to the temperature of the refrigerant in the outdoor heat exchanger being lower than the predetermined reference temperature, opening the second bypass valve, and in response to the temperature of the refrigerant in the outdoor heat exchanger being higher than or equal to the predetermined reference temperature, closing the second bypass valve.
An air conditioner comprising:

a compressor configured to compress a refrigerant;

an indoor heat exchanger disposed at a pipe connected to the compressor, and configured to perform heat exchange between the refrigerant and indoor air;

an outdoor heat exchanger disposed at a pipe which is connected to the compressor and at which the indoor heat exchanger is not disposed, and configured to perform heat exchange between the refrigerant and outside air;

an expansion device disposed at a pipe connecting the indoor heat exchanger and the outdoor heat exchanger, and configured to expand the refrigerant;

a defrosting bypass pipe having one end connected to a middle point of the outdoor heat exchanger, and the other end connected to an inlet pipe of the compressor; and

a defrosting bypass valve disposed at the defrosting bypass pipe.
The air conditioner of claim 13, wherein the outdoor heat exchanger comprises:

a first row in which a tube connected to the pipe connected to the compressor is disposed;

a third row in which a tube connected to a pipe connected to the expansion device is disposed; and

a second row, which is disposed between the first row and the third row and in which a tube connecting the tube in the first row and the tube in the third row is disposed,

wherein the defrosting bypass pipe is connected to the tube disposed in the second row.
The air conditioner of claim 14, wherein in the outdoor heat exchanger, a flow direction of the refrigerant in the first row is opposite to a flow direction of the refrigerant in the second row.
The air conditioner of claim 14, wherein in the outdoor heat exchanger, a lower end of the second row communicates with the first row, and an upper end of the second row communicates with the third row.
The air conditioner of claim 13, further comprising an accumulator disposed between the indoor heat exchanger and the compressor,

wherein the defrosting bypass pipe comprises:

a common bypass pipe connected to the outdoor heat exchanger;

a first bypass pipe branched from the common bypass pipe and connected to the inlet pipe of the compressor; and

a second bypass pipe branched from the common bypass pipe and connected to an inlet pipe of the accumulator.
The air conditioner of claim 17, wherein the defrosting bypass valve comprises:

a first bypass valve disposed on the first bypass pipe; and

a second bypass valve disposed on the second bypass pipe.