KR102399240B1 - Air conditioner and control method thereof - Google Patents

Abstract

An air conditioner according to an embodiment of the present invention includes a compressor for compressing a refrigerant; an indoor unit provided with an indoor heat exchanger; an outdoor heat exchanger in which a plurality of heat exchangers are stacked in multiple stages; a flow pipe extending from the indoor unit to the plurality of heat exchangers; an implantation detection means for detecting whether frost is formed on the plurality of heat exchangers; and a controller for controlling a defrosting operation of each of the plurality of heat exchangers based on the information sensed by the implantation detecting means, wherein the controller includes, when a defrosting operation of any one of the plurality of heat exchangers is performed , It is characterized in that the defrosting operation of the other heat exchanger is sequentially performed toward the lower side of the one heat exchanger.

Description

Air conditioner and control method thereof

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.

Meanwhile, in order to improve heat exchange efficiency, the air conditioner may include a variable flow path in which the refrigerant passing through the outdoor heat exchanger changes a flow path according to a cooling operation or a heating operation. That is, the refrigerant flowing to the outdoor heat exchanger according to the cooling operation or the heating operation may flow through the outdoor heat exchanger in series or in parallel through the variable flow path and pass therethrough.

Prior literature information related to this is as follows.

1. Publication number (disclosure date): 10-2013-0096960 (September 02, 2013)

Title of invention: air conditioner

However, the air conditioner disclosed in the prior literature has the following problems.

First, when the defrosting operation is performed, since the refrigerant circulation direction is switched from the heating cycle to the cooling cycle to perform defrosting of the outdoor heat exchanger, the indoor unit operates as an evaporator to cause a phenomenon in which the indoor temperature drops (cold draft). there is.

Second, in the case of returning to the heating operation, there is a problem in that it is difficult to provide heating to the room to operate in the normal heating operation range, that is, until a high pressure of a certain level is reached. In addition, there is a disadvantage in that power consumption is relatively increased until the high voltage of the predetermined level is reached.

Third, if the outdoor heat exchanger is provided with a plurality of heat exchangers in multiple stages, there is a problem in that the water melted through the defrosting operation flows downward, and the heat exchanger located at the lower part is easily implanted. In addition, there is a problem in that water is accumulated toward the lower part by the water melted from the upper heat exchanger, and the amount of implantation increases as the heat exchanger is positioned at the lower part.

Fourth, if the outdoor heat exchanger is provided with a plurality of heat exchangers in multiple stages, there is a problem in that an implantation occurs between the upper heat exchange unit and the lower heat exchange unit due to the melted water. In detail, since the heat exchanger in which the defrosting is performed operates as a condenser and the other heat exchangers operate as an evaporator, the temperature difference between the heat exchanger in which the defrosting is performed and the other heat exchangers is large. Therefore, there is a problem that a frost band on which water flowing down by defrosting occurs between the heat exchanger and the heat exchanger occurs.

Fifth, if the hot gas discharged from the compressor is bypassed to the outdoor heat exchanger for defrosting, the prior literature to which the variable flow path is applied has a problem in that the hot gas leaks through the variable flow path and prevents the refrigerant distribution of the evaporator. That is, there is a problem that the defrost performance is lowered.

It is an object of the present invention to provide an air conditioner capable of minimizing a decrease in indoor temperature 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 continuously providing heating to a room when a defrosting operation is performed, and rapidly reaching a normal heating operation range when returning to a heating operation, and a method for controlling the same. The purpose.

Another object of the present invention is to provide an air conditioner capable of solving the problem that water flowing down during a defrosting process of an upper heat exchanger in an outdoor heat exchanger having a plurality of heat exchangers in multiple stages is deposited on a lower heat exchanger and a control method thereof aim to do

Another object of the present invention is to solve a problem in that, in an outdoor heat exchanger having a plurality of heat exchangers in multiple stages, water flowing down during the defrosting process of the heat exchanger located at the upper part is accumulated and the amount of implantation of the heat exchanger located at the lower part is relatively increased. An object of the present invention is to provide an air conditioner and a control method therefor.

Another object of the present invention is to provide an air conditioner capable of solving a frost band problem occurring between a heat exchanger and a heat exchanger in an outdoor heat exchanger having a plurality of heat exchangers in multiple stages and a control method thereof.

Another object of the present invention is to provide an air conditioner and a control method thereof for solving a problem of hot gas leaking through a variable flow path.

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; an indoor unit provided with an indoor heat exchanger; an outdoor heat exchanger in which a plurality of heat exchangers are stacked in multiple stages; a flow pipe extending from the indoor unit to the plurality of heat exchangers; an implantation detection means for detecting whether frost is formed on the plurality of heat exchangers; and a controller for controlling a defrosting operation of each of the plurality of heat exchangers based on the information sensed by the implantation detecting means, wherein the controller includes, when a defrosting operation of any one of the plurality of heat exchangers is performed , It is characterized in that the defrosting operation of the other heat exchanger is sequentially performed toward the lower side of the one heat exchanger. According to this, a plurality of heat exchangers stacked in multiple stages are provided, and the heat exchanger performs a sequential defrosting operation downward, thereby minimizing a decrease in heating capacity compared to a normal heating operation. can come back quickly.

In addition, when the plurality of heat exchangers detects an implantation, the controller performs a defrosting operation of the heat exchanger located at the uppermost side among the plurality of heat exchangers. According to this, since the sequential defrosting operation is performed from the upper side to the lower side, the water flowing down from the upper heat exchanger can be transferred to the lower side while continuing to melt according to the defrosting operation of the lower heat exchanger.

In addition, the control unit is characterized in that the more the heat exchanger is located at the lower side, the defrosting operation execution time is increased. According to this, the defrosting time can be differentiated for each heat exchanger, and an appropriate defrosting operation can be performed according to the position of the heat exchanger.

In addition, an air conditioner according to an embodiment of the present invention includes: a discharge pipe provided on a discharge side of the compressor; a hot gas pipe branching from the discharge pipe; a branch pipe extending from the hot gas pipe to the flow pipe; and a hot gas valve installed in the branch pipe, wherein the plurality of heat exchangers are defrosted by the refrigerant flowing through the hot gas pipe.

The method further includes an expansion valve installed on the flow pipe, wherein the branch pipe is connected to the flow pipe between the expansion valve and the outdoor heat exchanger. Accordingly, the compressed refrigerant (hot gas) may be introduced into a heat exchanger requiring defrosting among a plurality of heat exchangers through the hot gas pipe and the hot gas valve.

In addition, an air conditioner according to an embodiment of the present invention includes a header; a variable flow path branching from the flow pipe and extending to the header; and a blocking unit installed in the variable flow path. According to this, efficient cooling and heating operations can be performed by applying the variable flow path.

In addition, the plurality of heat exchangers, the first heat exchanger located at the top; a second heat exchanger located below the first heat exchanger; a third heat exchanger located below the second heat exchanger; and a fourth heat exchanger located at the lowermost end. In addition, the outdoor heat exchanger includes an upper outdoor heat exchanger positioned on a high wind speed side and a lower outdoor heat exchanger positioned on a low wind speed side, wherein the upper outdoor heat exchanger includes the first to third heat exchangers. do. In addition, the variable flow path is characterized in that it is formed by branching from a flow pipe extending to the upper outdoor heat exchanger. According to this, it is possible to prevent leakage of hot gas to the heat exchanger operating as the evaporator along the variable flow path during the defrosting operation.

In addition, the control unit, the one heat exchanger and the heat exchanger located below the one heat exchanger is characterized in that it controls to simultaneously perform a defrosting operation for a preset overlap operation time (Toverlap). Accordingly, it is possible to reduce the temperature difference between the heat exchangers through the overlap operation time in the defrosting operation.

In another aspect, in order to achieve the above object, an air conditioner control method according to an embodiment of the present invention provides an outdoor heat exchanger in which a compressor, an indoor unit, and a plurality of heat exchangers are stacked in multiple stages, and from the indoor unit to the plurality of heat exchangers. In the air conditioner comprising a plurality of flow pipes extending, an expansion valve installed on the flow pipes, and a controller for controlling a defrosting operation of each of the plurality of heat exchangers, the plurality of heat exchanges based on information sensed by an impact detection means determining whether the stage is implanted; starting a defrosting of an n-th heat exchanger in which an implantation has occurred among the plurality of heat exchangers; determining whether a defrosting execution time (t) of the nth heat exchanger elapses a preset defrosting time (Tn); and starting the defrosting of an n+1th heat exchanger located below the nth heat exchanger when the defrosting execution time t elapses the defrosting time Tn. According to this, when the defrosting operation is performed in one heat exchanger, the defrosting of the heat exchanger located at the lower side may be sequentially performed.

In addition, in the air conditioner control method according to the embodiment of the present invention, the defrosting execution time t elapses an operation time (Tn+Toverlap) in which the defrost execution time t is added to the defrost time Tn by a preset overlap operation time (Toverlap). The method further comprises the step of determining whether or not, during the overlap operation time, it is characterized in that the defrosting of the nth heat exchanger and the n+1th heat exchanger is simultaneously performed. In addition, when the defrosting execution time (t) elapses the operation time (Tn+Toverlap), it is characterized in that the defrosting of the nth heat exchanger is terminated. Accordingly, it is possible to reduce the temperature difference between the upper and lower heat exchangers that may occur during the defrosting process.

In addition, the air conditioner control method according to an embodiment of the present invention further comprises the step of determining whether the n-th heat exchanger corresponds to the lowest heat exchanger when the defrosting time Tn has elapsed, wherein the control unit comprises: When the n-th heat exchanger corresponds to the lowest heat exchanger, the defrosting of the n-th heat exchanger is terminated.

In addition, the control unit, it characterized in that the control so that the defrost operation time of the n+1th heat exchanger is longer than the defrost operation time of the nth heat exchanger. According to this, since the defrosting operation execution time increases as the outdoor heat exchanger is located at the lower part, the optimized defrosting operation can be performed on the lower side heat exchanger in which the amount of implantation by the flowed water is relatively increased.

According to the present invention, it is possible to minimize the phenomenon that the indoor temperature falls during the defrost operation, and accordingly, when returning to the heating operation, it quickly returns to the normal range of the heating cycle, thereby minimizing power consumption and user inconvenience and performing effective indoor heating. There are advantages to doing. For example, when the outdoor heat exchanger is divided into four heat exchangers, there is an advantage in that the heating capacity can be continuously maintained by 75% or more even in the case of a defrosting operation.

According to the present invention, as the number of outdoor heat exchangers increases, there is an advantage in that it is possible to minimize a decrease in heating capacity due to a defrosting operation.

According to the present invention, the water flowing down during the defrosting operation of the upper heat exchanger through the sequential defrosting operation continues to flow downward, so that the water can be completely removed from the outdoor heat exchanger. Accordingly, there is an advantage in that the total defrosting operation time of the outdoor heat exchanger can be shortened. In addition, since the defrosting operation time for each heat exchanger is differentiated according to the location, there is an advantage in that frost can be efficiently defrosted due to the effect of water accumulating in the lower part.

According to the present invention, it is possible to prevent the occurrence of a frost band through a decrease in the temperature difference between the heat exchangers, so that it is possible to improve the defrosting performance.

According to the present invention, there is an advantage that a selective defrosting operation can be performed for each heat exchanger by adjusting the hot gas valve. That is, there is an advantage in that heating can be continuously provided to the room.

According to the present invention, since a variable flow path is applied, it is efficiently cooled. Heating may be provided to the room. In addition, when the defrosting operation is performed, it is possible to prevent the hot gas from flowing into the evaporator due to the variable flow path, so that the defrosting is easily performed. In addition, since the performance of the heat exchanger operating as an evaporator is maintained, it is possible to minimize the decrease in heating capacity due to the defrosting operation.

1 is a schematic overall configuration diagram 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;
5A is a view showing a first defrosting operation of the air conditioner according to an embodiment of the present invention;
5B is a view showing a second defrosting operation of the air conditioner according to an embodiment of the present invention;
5C is a view showing a third defrosting operation of the air conditioner according to an embodiment of the present invention;
5D is a view showing a fourth defrosting operation of the air conditioner according to an embodiment of the present invention;
6 is a flowchart illustrating a control method for a defrosting operation of an air conditioner according to an embodiment of the present invention;
7 is a graph showing an opening/closing operation of a hot gas valve and an implantation amount of a heat exchanger over time 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 schematic overall configuration diagram of an air conditioner according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a control unit of the air conditioner according to an embodiment of the present invention.

1 and 2, the air conditioner according to an embodiment of the present invention includes a compressor 10 for compressing a refrigerant, an oil separator 11 for separating oil of the refrigerant discharged from the compressor 10, and evaporation It may include an accumulator 13 for separating the liquid phase and the gas phase of the refrigerant.

The oil separator 110 may be connected to a discharge side of the compressor 10 . For example, the pipe extending from the discharge side of the compressor 10 may be connected by the suction side of the oil separator 110 . Accordingly, the compressed refrigerant compressed at high temperature and high pressure in the compressor 10 may flow into the oil separator 110 to separate oil.

The oil separator 110 may include an oil return pipe 12 for recovering the separated oil to the compressor 10 . The oil return pipe 12 may be connected to the suction side of the compressor 10 . Accordingly, the oil separated by the oil separator 110 may be recovered to the suction side of the compressor 10 by the oil return pipe 12 .

The accumulator 13 may be connected to the suction side of the compressor 10 . In detail, a suction pipe 14 for guiding the separated gaseous refrigerant to the compressor 10 may be provided on the discharge side of the accumulator 13 . The suction pipe 14 may extend from the accumulator 13 and be connected to a point of the oil return pipe 12 . Accordingly, the gaseous refrigerant separated from the accumulator 13 may be introduced into the compressor 10 along the suction pipe 14 .

Meanwhile, an accumulator pipe 22 may be provided on the suction side of the accumulator 13 . The accumulator pipe 22 may guide the evaporated refrigerant to flow into the accumulator 13 . For example, the accumulator pipe 22 may extend from the flow conversion unit 20 and be connected to the suction side of the accumulator 13 .

In addition, the air conditioner includes the flow conversion unit 20 for changing the flow direction of the refrigerant, the outdoor heat exchangers 60 and 64 for exchanging heat with outdoor air, the indoor unit 30 for providing cooling or heating to the room, and the outdoor heat exchange Expansion valves 51 , 52 , 53 , and 54 for expanding the refrigerant between the units 60 and 64 and the indoor unit 30 may be further included.

The flow conversion unit 20 may include a four-way valve for switching the flow direction of the refrigerant.

The indoor unit 30 may include an indoor heat exchanger performing heat exchange between indoor air and a refrigerant and a plurality of valves. The indoor unit 30 may operate as an evaporator or a condenser to provide cooling or heating to the room.

The expansion valves 51 , 52 , 53 , and 54 may include an electronic expansion valve (EEV).

The outdoor heat exchangers 60 and 64 may include a plurality of heat exchangers 61, 62, 63, and 64 stacked in multiple stages.

And outdoor heat exchangers (60, 64) provided in multiple stages. Due to the relatively easy contact with the air and the upper outdoor heat exchanger 60 located at the upper portion of the high wind speed side of the air flow and the surrounding components, the lower outdoor portion is located in the lower part with relatively little contact with air and the wind speed is relatively slow. It can be divided into a heat exchanger (64).

The outdoor heat exchangers 60 and 64 may include a first heat exchanger 61 , a second heat exchanger 62 , a third heat exchanger 63 , and a fourth heat exchanger 64 .

The first to fourth heat exchangers 61 , 62 , 63 , and 64 may be stacked in multiple stages. For example, the first heat exchanger 61 is located at the uppermost portion, the second heat exchanger 62 is located below the first heat exchanger 61 , and the second heat exchanger 62 is located below the second heat exchanger 62 . The third heat exchanger 63 is positioned in the , and the fourth heat exchanger 64 is positioned below the third heat exchanger 63 .

Here, the first heat exchanger 61 , the second heat exchanger 62 , and the third heat exchanger 63 may be located at an upper portion where contact with outdoor air is relatively easy. That is, the upper outdoor heat exchanger 60 may include the first heat exchanger 61 , the second heat exchanger 62 , and the third heat exchanger 62 .

In addition, the fourth heat exchanger 64 may be located at a lower portion where it is relatively difficult to contact outdoor air. That is, the lower outdoor heat exchanger 64 may include the fourth heat exchanger 64 .

The first to fourth heat exchangers 61 , 62 , 63 , and 64 may be stacked to have the same width in both directions and different lengths in the vertical direction. For example, the length of the fourth heat exchanger 64 that is relatively difficult to contact with outdoor air may be formed to be longer than the length of the first to third heat exchangers 61 , 62 , and 63 . In addition, the length of the third heat exchanger 63 may be formed to be longer than the length of the first to second heat exchangers 61 and 62, and the length of the second heat exchanger 62 is the length of the first heat exchanger ( 61) may be formed longer than the length. Accordingly, it is possible to minimize the difference in heat exchange efficiency due to the air flow rate that is different for each length in the vertical direction, ie, height.

Meanwhile, the upper outdoor heat exchanger 60 and the lower outdoor heat exchanger 64 are connected in parallel during a heating operation, and are connected in series during a cooling operation by variable flow paths 101 , 102 , 103 , and 105 to be described later. At this time, even when the cooling operation is performed, the first to third heat exchangers 61 , 62 , 63 constituting the upper outdoor heat exchanger 60 may maintain parallel connection. Accordingly, it is possible to maximize the efficiency of the refrigerant performing heat exchange with the outdoor air in the outdoor heat exchangers 60 and 64 .

The outdoor heat exchangers 60 and 64 in the embodiment of the present invention will be described on the basis that four heat exchangers 61, 62, 63, and 64 are stacked in multiple stages. However, the number of the heat exchangers is not limited thereto, but in order to provide a certain level (75% or more) of heating ability while performing a defrosting operation, it will be preferable to provide four or more heat exchangers.

The air conditioner includes a discharge pipe 21 extending from the oil separator 11 to the flow conversion unit 20 , and an indoor connecting pipe 24 extending from the flow conversion unit 20 to the indoor unit 30 . and an outdoor connecting pipe 23 extending from the flow conversion unit 20 toward the outdoor heat exchangers 60 and 64 .

The discharge pipe 21 may connect the discharge side of the oil separator 11 and the flow conversion unit 20 . In addition, the discharge pipe 31 may guide the refrigerant that has passed through the oil separator 11 , that is, the high-temperature and high-pressure compressed refrigerant discharged from the compressor 10 to the flow conversion unit 20 .

The outdoor connection pipe 23 may guide the refrigerant between the flow conversion unit 20 and the outdoor heat exchangers 60 and 64 . For example, when a scattering operation is performed, the refrigerant that has passed through the outdoor heat exchangers 60 and 64 flows to the flow conversion unit 20 along the outdoor connection pipe 23 and flows to the aquarium pipe 22 . is brought in And when the cooling operation is performed, the compressed refrigerant introduced into the flow conversion unit 20 may flow toward the outdoor heat exchangers 60 and 64 along the outdoor connection pipe 23 .

The indoor connection pipe 24 may guide the refrigerant between the flow conversion unit 20 and the indoor unit 30 . For example, when a heating operation is performed, the compressed refrigerant flowing into the flow conversion unit 20 may be introduced into the indoor unit 30 along the indoor connection pipe 24 . In addition, when the cooling operation is performed, the refrigerant that has passed through the indoor unit 30 flows to the flow conversion unit 20 along the indoor connection pipe 24 and flows into the air conditioning pipe 22 .

The air conditioner may further include a refrigerant passage 35 for guiding the refrigerant between the indoor unit 30 and the expansion valves 51 , 52 , 53 and 54 .

The refrigerant passage 35 may be connected to one side of the indoor unit 30 . In this case, the indoor connector 24 may be connected to the other side of the indoor unit 30 .

Based on the heating operation, the refrigerant flow path 35 is provided on the discharge side of the indoor unit 30 to guide the condensed refrigerant passing through the indoor unit 30 toward the expansion valves 51 , 52 , 53 and 54 . can

The air conditioner may further include flow pipes 41 , 42 , 43 , 44 extending from the refrigerant passage 35 to the outdoor heat exchangers 60 and 64 .

The flow pipes 41 , 42 , 43 , and 44 may extend to a plurality of heat exchangers 61 , 62 , 63 , and 64 so that the refrigerant is branched from the refrigerant passage 35 . That is, the flow pipes 41 , 42 , 43 , and 44 may branch and extend from the refrigerant passage 35 to correspond to the number of heat exchangers 61 , 62 , 63 and 64 .

Of course, the refrigerant passage 25 and the flow pipes 41, 42, 43, 44 may be integrally formed. That is, the flow pipes 41 , 42 , 43 , and 44 may extend from one side of the indoor unit 30 to the heat exchangers 61 , 62 , 63 and 64 .

The flow pipes 41 , 42 , 43 , and 44 may include a first flow pipe 41 , a second flow pipe 42 , a third flow pipe 43 , and a fourth flow pipe 44 .

The first flow pipe 41 may branch off at any one point of the refrigerant passage 35 and extend to the first heat exchanger 61 . At this time, a point at which the first flow pipe 41 is branched from the refrigerant passage 35 may be referred to as a first branch point.

The second flow pipe 42 may be branched from another point of the refrigerant passage 35 and extend to the second heat exchanger 62 . In this case, another point at which the second flow pipe 42 is branched from the refrigerant passage 35 may be referred to as a second branch point.

The third flow pipe 43 may be branched from another point of the refrigerant passage 35 and extend to the third heat exchanger 63 . In this case, another point at which the third flow pipe 43 is branched from the refrigerant passage 35 may be referred to as a third branch point.

The fourth flow pipe 44 may be branched from another point of the refrigerant passage 35 and extend to the fourth heat exchanger 64 . At this time, another point at which the fourth flow pipe 44 is branched from the refrigerant passage 35 may be referred to as a fourth branch point.

The expansion valves 51 , 52 , 53 and 54 may be installed in the flow pipes 41 , 42 , 43 and 44 . In detail, the expansion valves (51, 52, 53, 54) include a first expansion valve (51) installed in the first flow pipe (41), a second expansion valve (52) installed in the second flow pipe (42), and a second expansion valve (52) installed in the second flow pipe (42). It may include a third expansion valve 53 installed in the third flow pipe 43 and a fourth expansion valve 54 installed in the fourth flow pipe 44 .

In addition, distributors 46 , 47 , 48 , 49 may be installed in the flow pipes 41 , 42 , 43 , and 44 . In this case, one side of the distributor (46,47,48,49) is connected to the flow pipe (41,42,43,44), and the other side of the distributor (46,47,48,49) is a plurality of narrow tubes. can be connected to And the narrow tube may be connected to the heat exchangers (61, 62, 63, 64).

Based on the heating operation, the distributors 46 , 47 , 48 and 49 may be located downstream of the expansion valves 51 , 52 , 53 and 54 . Accordingly, the refrigerant expanded through the expansion valves 51, 52, 53, 54 can flow to the plurality of heat exchangers 61, 62, 63, and 64 through the distributors 46, 47, 48, and 49. there is.

The distributors 46 , 47 , 48 and 49 include a first distributor 46 installed in the first flow pipe 41 , a second distributor 47 installed in the second flow pipe 42 , and the third It may include a third distributor 68 installed in the flow pipe 43 and a fourth distributor 49 installed in the fourth flow pipe 44 .

Based on the heating operation, the refrigerant flowing through the flow pipes 41 , 42 , 43 , 44 flows into the distributors 46 , 47 , 48 , 49 and then branches through the plurality of narrow tubes to generate a heat exchanger 61 ,62,63,64).

The air conditioner is located between the outdoor heat exchangers 60 and 64 and the flow conversion unit 20 to guide the refrigerant from the header 80 and the outdoor heat exchangers 60 and 64 to the header 80. It may further include a header connector extending (71, 72, 73, 74).

The outdoor connector 23 may extend from the flow diverter 20 and be connected to the header 80 .

Based on the heating operation, the flow pipes 41, 42, 43, 44 are connected to the inlet side of the outdoor heat exchangers 60 and 64, and the outlet side of the outdoor heat exchangers 60 and 64 are connected to the header connection pipe ( 71,72,73,74) are connected. In addition, the refrigerant introduced into the header connection pipes 71 , 72 , 73 , and 74 through the outdoor heat exchangers 60 and 64 may be combined in the header 80 .

That is, the header 80 guides the refrigerant to branch and flow to the header connection pipes 71, 72, 73, and 74, or the refrigerant introduced from the header connection pipes 71, 72, 73, and 74 It can be guided to be laminated. For example, refrigerant flowing through each header connection pipe 71 , 72 , 73 , 74 during heating operation may be combined in the header 80 to flow, and refrigerant flowing through the header 80 during cooling operation may be branched to the header connection pipe (71, 72, 73, 74) and flow.

The header connector pipe (71, 72, 73, 74) connects the first header connector pipe (71), the second header connector pipe (72), the third header connector pipe (73), and the fourth header connector pipe (74) to each other. may include

The first header connection pipe 71 may extend from the first heat exchanger 61 to any one point of the header 80 . In this case, one point of the header 80 to which the first header connector 71 is connected may be called a first junction point.

The second header heat coupling pipe 72 may extend from the second heat exchanger 62 to another point of the header 80 . In this case, another point of the header 80 to which the second header connector 72 is connected may be called a second junction point. The second junction point may be located below the first junction point.

The third header connection pipe 73 may extend from the third heat exchanger 63 to another point of the header 80 . In this case, another point of the header 80 to which the third header connector 73 is connected may be called a third joint point. The third junction may be located below the second junction.

The fourth header connection pipe 74 may extend from the fourth heat exchanger 64 to another point of the header 80 . In this case, another point of the header 80 to which the fourth header connector 74 is connected may be referred to as a fourth joint point. The fourth junction may be located below the third junction.

That is, based on the heating operation, the refrigerant condensed through the indoor unit 30 branches at the first to fourth branch points and flows into each of the flow pipes 41 , 42 , 43 and 44 , and then each It can expand while passing through the expansion valves (51, 52, 53, 54) installed in the flow pipe. In addition, the expanded refrigerant may evaporate while passing through the first to fourth heat exchangers 61 , 62 , 63 and 64 . The refrigerant evaporated through the first to fourth heat exchangers 61 , 62 , 63 and 64 may be combined and flowed while flowing into the header 80 through the first to fourth junctions.

A check valve 81 for guiding the flow of the refrigerant in one direction may be installed in the header 80 . In detail, the check valve 81 may be installed between the third junction and the fourth junction.

Based on the heating operation, the check valve 81 may allow the refrigerant introduced into the header 80 through the fourth header connection pipe 74 to flow into the outdoor connection pipe 23 . In addition, the check valve 81 may prevent the refrigerant flowing into the header 80 through the third header connection pipe 73 from flowing backward in the direction of the fourth header connection pipe 84 .

The air conditioner includes variable flow paths 101 , 102 , 103 , 105 extending from the flow pipes 41 , 42 , 43 connected to the upper outdoor heat exchanger 60 to the header 80 , and a blocking unit installed in the variable flow path 105 . (110) may be further included.

Here, a point where the variable flow paths 101 , 102 , 103 , and 105 are connected in the header 80 may be referred to as a variable point.

The variable point may be located between the check valve 81 and the fourth junction.

The variable flow paths 101 , 102 , 103 , and 105 may be formed to branch from the flow pipes 41 , 42 , 43 extending to the upper outdoor heat exchanger 60 .

In more detail, the variable flow path 101, 102, 103, 105 includes a combined passage 105 connected to the header 80, a first variable passage 101 extending from the first flow pipe 41 to the combined passage 105, A second variable passage 102 extending from the second flow pipe 42 to the combined passage 105 and a third variable passage 103 extending from the third flow tube 43 to the combined passage 105 were formed. may include

The paper passage 105 may connect the first to third variable passages 101 , 102 , 103 on one side, and may be connected with the header 80 on the other side. That is, the paper passage 105 extends from the first to third variable passages 101 , 102 , and 103 to the header 80 . Accordingly, the combined flow path 105 may guide the refrigerant flowing through the first to third variable flow paths 101 , 102 , and 103 to be laminated and flow to the header 80 .

The first variable flow path 101 may be branched at a point between the first expansion valve 51 and the first distributor 46 to extend to the paper flow path 105 .

The second variable flow path 102 may be branched at a point between the second expansion valve 52 and the second distributor 47 to extend to the paper flow path 105 .

The third variable flow path 103 may be branched at a point between the third expansion valve 53 and the third distributor 48 to extend to the paper flow path 105 .

Variable valves 106 , 107 , and 108 for controlling the flow of the refrigerant may be installed in the first to third variable passages 101 , 102 , and 103 .

The variable valves 106 , 107 , and 108 may include check valves. For example, the variable valves 106 , 107 , and 108 include a first variable valve 106 installed in the first variable passage 101 , a second variable valve 107 installed in the second variable passage 102 , and a third variable passage It may include a third variable valve 108 installed in the (103).

The variable valves 106 , 107 , and 108 may allow the refrigerant to flow from the first to third variable flow paths 101 , 102 , 103 toward the combined flow path 105 . And, the refrigerant flow in the reverse direction can be prevented.

According to this, when the compressed refrigerant (hot gas) flows into any one of the first to third flow pipes 41, 42, and 43 in a defrosting operation to be described later, the compressed refrigerant (hot gas) flows into the variable flow passages 101, 102, 103. There is an advantage in that it can be prevented from flowing into a flow pipe connected to a heat exchanger that does not defrost through the evaporator, that is, a heat exchanger that operates as an evaporator.

The blocking unit 110 may be installed in the paper passage 115 . And the blocking unit 110 may guide the flow direction of the refrigerant through an opening/closing operation according to a cooling or heating operation.

In addition, the blocking unit 110 may perform a function of adjusting the flow rate or pressure of the refrigerant flowing through the variable flow paths 101 , 102 , 103 , and 105 .

The shut-off unit 110 may include a shut-off valve 115 for controlling the flow of the refrigerant and a capillary 116 for adjusting the pressure of the refrigerant. The shut-off valve 115 may include a solenoid valve and an electronic expansion valve (EEV).

The air conditioner includes a hot gas pipe 90 branching from the discharge pipe 21 , and branch pipes 91 , 92 , 93 extending from the hot gas pipe 90 to a plurality of flow pipes 41 , 42 , 43 , 44 . , 94) and may further include hot gas valves 96, 97, 98, and 99 installed in the branch pipes 91, 92, 93, and 943.

The hot gas pipe 90 may branch off at one point of the discharge pipe 21 and extend to the flow pipes 41 , 42 , 43 , and 44 .

The compressed refrigerant (hot gas) flowing through the discharge pipe 21 may be branched by the hot gas pipe 90 . In addition, the branched compressed refrigerant (hot gas) may be introduced into the hot gas pipe 90 and bypassed to the flow pipes 41 , 42 , 43 , 44 .

The compressed refrigerant (hot gas) introduced into the hot gas pipe 90 may be provided to the heat exchangers 61 , 62 , 63 , 64 requiring defrosting among the plurality of heat exchangers 61 , 62 , 63 , 64 . there is.

In more detail, the compressed refrigerant (hot gas) flows from the hot gas pipe 90 to the flow pipes 41, 42, 43, 44 extending from the hot gas pipe 90 to the heat exchangers 61, 62, 63, 65 that require defrosting. 91,92,93,94). That is, the branch pipes 91 , 92 , 93 , and 94 may guide the refrigerant flowing through the hot gas pipe 90 to flow into the flow pipes 41 , 42 , 43 , and 44 .

Points at which the branch pipes 91, 92, 93, and 94 extend and are connected to the flow pipes 41, 42, 43, 44 are the expansion valves 51, 52, 53, 54 and the distributors 46, 47, 48, 49).

The branch pipes 91 , 92 , 93 , and 94 are a first branch pipe 91 , a second branch pipe 92 , a third branch pipe 94 and a fourth branch pipe branching from the hot gas pipe 90 , respectively. It may include a branch tube 94 .

The first branch pipe 91 may branch at any one point of the hot gas pipe 90 and extend to the first flow pipe 41 . The second branch pipe 92 may be branched from another point of the hot gas pipe 90 to extend to the second flow pipe 42 . The third branch pipe 93 may branch at another point of the hot gas pipe 90 and extend to the third flow pipe 43 . The fourth branch pipe 94 may be branched from another point of the hot gas pipe 90 to extend to the fourth flow pipe 44 .

Of course, the fourth branch pipe 64 may be integrally formed with the hot gas pipe 90 . In this case, the hot gas pipe 90 may directly extend to the fourth flow pipe 44 .

The hot gas valves 96 , 97 , 98 , and 99 may allow or block the inflow of refrigerant from the hot gas pipe 90 to the branch pipes 91 , 92 , 93 , and 94 . That is, the hot gas valves 96 , 97 , 98 , and 99 may control the refrigerant flow in the branch pipes 91 , 92 , 93 , and 94 through an opening and closing operation. Accordingly, the hot gas valves 96, 97, 98, and 99 may open and close so that the compressed refrigerant (hot gas) is provided to the heat exchangers 61, 62, 63, and 64 requiring defrosting.

The hot gas valves 96, 97, 98, and 99 may include a solenoid valve (SV), an electronic expansion valve (EEV), and the like.

In addition, the hot gas valves 96 , 97 , 98 , 99 include a first hot gas valve 96 installed in the first branch pipe 91 and a second hot gas valve 96 installed in the second branch pipe 92 . It may include a hot gas valve 97, a third hot gas valve 98 installed in the third branch pipe 93, and a fourth hot gas valve 99 installed in the fourth branch pipe 94. there is.

On the other hand, the air conditioner can control the operation of the air conditioner based on an implantation detection means capable of detecting whether frost has formed on the outdoor heat exchangers 60 and 64 and the information sensed by the impaction detection means. The control unit 200 may further include.

The controller 200 may control each component of the air conditioner to perform a cooling operation, a heating operation, a defrosting operation, and the like. For example, the control unit 200 may determine the flow direction of the refrigerant by controlling the flow conversion unit 20 and the blocking unit 110 for a cooling operation or a heating operation.

In addition, the control unit 200 controls the expansion valves 51, 52, 53, 54 and the hot gas valves 96, 97, 98, and 99 to perform a defrosting operation to provide continuous heating to the room. can (See Fig. 2)

The implantation detection means may include an outdoor temperature sensor (not shown) and temperature sensors 76, 77, 78, and 79 provided in the plurality of heat exchangers 61, 62, 63, and 64. For example, the temperature sensors 76 , 77 , 78 , and 79 may be installed on one side of the plurality of heat exchangers 61 , 62 , 63 and 64 . In detail, the first temperature sensor 76 may be installed in the first heat exchanger 61 , the second temperature sensor 77 may be installed in the second heat exchanger 62 , and the third temperature sensor 78 . ) may be installed in the third heat exchanger 63 , and the fourth temperature sensor 79 may be installed in the fourth heat exchanger 64 .

The control unit 200 may determine whether the heat exchangers 61, 62, 63, and 64 are implanted during the heating operation through the outdoor temperature sensor and the first to fourth temperature sensors 76, 77, 78, 79. there is. For example, when the outdoor temperature is 0 °C or higher, when the temperature measured by at least one of the plurality of temperature sensors 61, 62, 63, 64 is less than -7 °C, defrosting the heat exchanger can drive.

The controller 200 may control whether or not the expansion valves 51, 52, 53, 54 and the hot gas valves 96, 97, 98, and 99 are opened or closed when a defrosting operation is performed.

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

Referring to FIG. 3 , when the cooling operation is performed, the refrigerant discharged from the compressor 10 flows into the outdoor connection pipe 23 through the flow conversion unit 20 . At this time, since the hot gas valves 96 , 97 , 98 , and 99 are all closed in a locked state, the refrigerant flowing through the discharge pipe 21 does not flow into the hot gas pipe 90 and does not flow into the outdoor connection pipe ( 23) will flow.

The refrigerant introduced into the outdoor connection pipe 23 may flow to the upper outdoor heat exchanger 60 through the header 80 . At this time, the refrigerant flowing into the header 80 is restricted from flowing into the lower outdoor heat exchanger 64 by the check valve 81 .

In the cooling operation, the variable valves 106 , 107 , 108 and the shut-off unit 110 are opened. And the first to third expansion valves (51, 52, 53) are closed. Accordingly, the refrigerant that has passed through the upper outdoor heat exchanger 60 may flow to the lower outdoor heat exchanger 64 through the variable flow paths 101 , 102 , 103 , and 105 .

That is, in the cooling operation, the upper outdoor heat exchanger 60 and the lower outdoor heat exchanger 64 are connected in series to perform heat exchange between the refrigerant and outdoor air. As a result, the outdoor heat exchangers 60 and 64 according to the embodiment of the present invention may be provided as variable paths in which the upper and lower portions are connected in series when a cooling operation is performed and are connected in parallel when a heating operation is performed. . According to this, the refrigerant path can be relatively increased (evaporator) or decreased (condenser) according to the function of the outdoor heat exchangers 60 and 64 operating as a condenser or an evaporator depending on the operation mode, so the state of the refrigerant heat exchange suitable for Accordingly, the performance of the outdoor heat exchangers 60 and 64 can be improved.

However, even when the cooling operation is performed, the first heat exchanger 61 , the second heat exchanger 62 , and the third heat exchanger 63 corresponding to the upper outdoor heat exchanger 60 may be connected in parallel. According to this, the pressure loss of the refrigerant can be reduced, and the heat exchange performance can be further improved.

Meanwhile, the refrigerant condensed through the upper outdoor heat exchanger 60 and the lower outdoor heat exchanger 64 may be expanded while passing through the fourth expansion valve 54 . The expanded refrigerant flows into the refrigerant passage 35 , passes through the indoor unit 30 , is evaporated, and is recovered to the compressor 10 .

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

Referring to FIG. 4 , when the heating operation is performed, the first to fourth hot gas valves 96, 97, 98, and 99 are locked (closed), and the first to fourth expansion valves 51 and 52 ,53,54) is an open state. And the blocking unit 110 may be in a locked (closed) state to block the flow of refrigerant into the variable flow paths 101, 102, 103, and 105.

In the heating operation, the compressed refrigerant discharged from the compressor 10 may be introduced into the indoor unit 30 along the indoor connection pipe 24 and condensed. The refrigerant condensed in the indoor unit 30 may be introduced into the first to fourth flow pipes 41 , 42 , 43 and 44 along the refrigerant passage 35 . And it can be expanded by the expansion valves (51, 52, 53, 54) installed in each of the flow pipes (41, 42, 43, 44).

As described above, in the heating operation, since the upper outdoor heat exchanger 60 and the lower outdoor heat exchanger 64 are connected in parallel, the refrigerant expanded by the expansion valves 51, 52, 53, 54 is 41 , 42 , 43 , 44 may flow to the first to fourth heat exchangers 61 , 62 , 63 and 64 . In addition, the refrigerant that has passed through the first to fourth heat exchangers 61 , 62 , 63 , and 64 is evaporated, is combined in the header 80 , and can be recovered back to the compressor 10 .

5A is a view showing a first defrosting operation of the air conditioner according to an embodiment of the present invention, FIG. 5B is a view showing a second defrosting operation of the air conditioner according to an embodiment of the present invention, and FIG. 5C is the present invention It is a view showing a third defrosting operation of the air conditioner according to an embodiment of the present invention, and FIG. 5D is a view showing a fourth defrosting operation of the air conditioner according to an embodiment of the present invention.

The control unit 200 may determine whether frost is formed in the first to fourth heat exchangers 61 , 62 , 63 , 64 based on the result detected by the implantation detecting means in real time while the heating operation is performed. And when it is determined that frost has formed on the first heat exchanger 61, the control unit 200 may perform a first defrost operation.

Since the defrosting operation in which the first to fourth heat exchangers 61, 62, 63, and 64 are defrosted is performed during the heating operation, the blocking unit 110 maintains a blocked (closed) state in the same manner as in the heating operation. can keep

Referring to FIG. 5A , the first defrosting operation may be defined as an operation in which frost is formed on the first heat exchanger 61 to perform defrosting.

In the first defrosting operation, the first hot gas valve 96 is opened and the second to fourth hot gas valves 97, 98, and 99 are blocked (closed). And the first expansion valve 51 is blocked (closed), and the second to fourth expansion valves 52, 53, 54 are opened.

In the first defrosting operation, since the first hot gas valve 96 is opened, the compressed refrigerant (hot gas) flowing through the discharge pipe 21 may flow into the hot gas pipe 90 . In addition, the compressed refrigerant introduced into the hot gas pipe 90 may be introduced into the first flow pipe 41 through the first branch pipe 91 . At this time, since the first expansion valve 51 is in a blocked state, the condensed refrigerant in the refrigerant passage 35 does not flow into the first flow tube 41 .

In addition, the compressed refrigerant (hot gas) introduced into the first flow pipe 41 is a second variable valve 107 installed in the second variable flow path 102 and a third variable valve 107 installed in the third variable flow path 103 . Due to the variable valve 108 , even if a portion flows into the first variable flow path 101 , the second flow pipe 42 or the third flow pipe 43 does not flow backward. Accordingly, all of the compressed refrigerant (hot gas) introduced into the first flow pipe 41 may be introduced into the first heat exchanger 61 .

Since the compressed refrigerant introduced into the first flow pipe 41 is in a high temperature state, the first heat exchanger 61 may have the same environment as operating as a condenser in the first defrosting operation. That is, the frost implanted on the first heat exchanger 61 by the flow of the compressed refrigerant may melt and flow down.

The control unit 200 may perform the first defrost operation for a set predetermined time (T1+Toverlap). Here, the set predetermined time (T1+Toverlap) may be referred to as a first operation time.

In detail, the first operation time is a time during which the first defrost time T1 and the second defrost operation determined by sensing the temperature change of the first heat exchanger 61 through the first temperature sensor 76 are simultaneously performed. It can be defined as the time plus the overlap operation time (Toverlap). That is, the control unit 200 may perform the first defrosting operation until the first operation time (T1+Toverlap) elapses.

The control unit 200 may end the first defrosting operation when the first operation time (T1+Toverlap) has elapsed. At this time, the control unit 200 controls to switch the first hot gas valve 96 to the shut-off (closed) state and to switch the first expansion valve 51 to the open state, so that the first heat exchanger 61 is You can make it work again as an evaporator.

Meanwhile, in the first defrosting operation, the second to fourth expansion valves 52 , 53 and 54 expand the refrigerant in the same manner as in the heating operation, and thus the second to fourth heat exchangers 62 , 63 and 64 . The refrigerant passing through may be introduced into the header 80 in an evaporated state.

Accordingly, when the first defrosting operation is performed, since the second to fourth heat exchangers 62 , 63 , and 64 continuously operate as evaporators, indoor heating can be continuously provided.

In addition, even when a second defrosting operation to be described later is performed, since the first heat exchanger 61 , the third heat exchanger 63 , and the fourth heat exchanger 64 operate as an evaporator, indoor heating may be continuously provided. can

After all, when the defrosting operation according to the embodiment of the present invention is performed, since 75% of the heat exchangers 60 and 64 maintain the evaporator operation, there is an advantage in that it is possible to minimize the decrease in heating capacity due to the defrost operation. That is, it is possible to minimize the phenomenon that the indoor temperature drops during the defrost operation, and accordingly, there is an advantage in that it is possible to quickly return to the normal range of the heating cycle when the heating operation is returned. Accordingly, there is an effect of minimizing power consumption and user inconvenience, and performing effective indoor heating.

Referring to FIG. 5B , the second defrosting operation may be defined as an operation in which frost is formed on the second heat exchanger 62 to perform defrosting.

The control unit 200 performs a second defrost operation when it is determined that the first defrost time T1 has elapsed or it is determined that frost has formed on the second heat exchanger 62 based on the result detected by the implantation detection means. can do.

Here, the first defrost operation and the second defrost operation may be simultaneously performed during the overlap operation time (Toverlap) from the time when the first defrost time T1 has elapsed.

According to this, it is possible to prevent the water formed by melting by the first defrosting operation from re-implanting on the second heat exchanger 62, and there is an advantage in that it can be guided to flow down in sequence.

In addition, according to this, since the temperature difference between the first heat exchanger 61 located at the upper side and the second heat exchanger 62 located at the lower side of the first heat exchanger 61 can be minimized, as described above, the heat exchanger There is an advantage of being able to prevent in advance a frost band that may be formed due to a large temperature difference between them.

In the second defrosting operation, the second hot gas valve 97 is opened, and the first hot gas valve 96, the third hot gas valve 98 and the fourth hot gas valve 99 are blocked (closed). do. Then, the second expansion valve 52 is blocked (closed), and the first expansion valve 51, the third expansion valve 53, and the fourth expansion valve 54 are opened.

In the second defrosting operation, since the second hot gas valve 97 is opened, the compressed refrigerant (hot gas) flowing along the hot gas pipe 90 passes through the second branch pipe 92 through the second flow pipe. (42) can be introduced. At this time, since the second expansion valve 52 is in a closed state, the condensed refrigerant in the refrigerant passage 35 does not flow into the second flow tube 42 .

In addition, the compressed refrigerant (hot gas) introduced into the second flow pipe 42 is supplied with a first variable valve 106 installed in the first variable flow passage 101 and a third variable valve 106 installed in the third variable flow passage 103 . Due to the variable valve 108 , even if a portion flows into the second variable flow path 102 , no backflow into the first flow pipe 41 or the third flow pipe 43 is performed.

Therefore, all of the compressed refrigerant (hot gas) introduced into the second flow pipe 42 may be introduced into the second heat exchanger 62, and as described above, the second heat exchanger 62 through the high-temperature compressed refrigerant. of defrost can be performed.

The controller 200 may perform the second defrosting operation until a set predetermined time (T2+Toverlap) has elapsed. Here, the set predetermined time (T2+Toverlap) may be referred to as a second driving time. Specifically, the second defrost operation may be performed for a time obtained by subtracting the first defrost time T1 from a second operation time (T2+Toverlap).

In detail, the second operation time (T2+Toverlap) is a second defrost time (T2) determined by detecting a temperature change of the second heat exchanger (62) through the second temperature sensor (77) and the overlap operation time ( Toverlap) can be defined as the added time (T2+Toverlap).

That is, the control unit 200 may perform the second defrosting operation until the second operation time (T2+Toverlap) elapses.

Meanwhile, the second defrosting operation may be performed for a longer time than the first defrosting operation. That is, since the overlap operation time (Toverlap) is set to be the same, the difference between the second defrost time T2 and the first defrost time T1 may be set to be greater than the first defrost time T1. According to this, there is an advantage in that it is possible to effectively remove the frost formation that may occur as the water generated during the defrosting process of the heat exchanger located on the upper side flows down and accumulates.

When the second operation time (T2+Toverlap) has elapsed, the control unit 200 may end the second defrosting operation. At this time, the control unit 200 controls the second hot gas valve 97 to be switched to a blocked (closed) state and the second expansion valve 52 to be switched to an open state, whereby the second heat exchanger 62 is can again act as an evaporator.

Meanwhile, in the second defrosting operation, the first expansion valve 51 , the third expansion valve 53 , and the fourth expansion valve 54 expand the refrigerant in the same manner as in the heating operation, so that the first heat exchanger ( 61), the refrigerant that has passed through the third heat exchanger 63 and the fourth heat exchanger 64 may be introduced into the header 80 in an evaporated state. Accordingly, even when the second defrosting operation is performed, indoor heating can be continuously provided and, as described above, 75% of the heat exchangers 60 and 64 can maintain the operation of the evaporator.

Referring to FIG. 5C , the third defrosting operation may be defined as an operation in which frost is formed on the third heat exchanger 63 to perform defrosting.

The control unit 200 performs a third defrost operation when it is determined that the second defrost time T2 has elapsed or it is determined that frost has formed on the third heat exchanger 63 based on the result detected by the implantation detection means. can do.

Here, the second defrost operation and the third defrost operation may be simultaneously performed during the overlap operation time (Toverlap) after the second defrost time T2 has elapsed. According to this, as described above, it is possible to prevent the melt flowing water from forming in the lower heat exchanger during the defrosting process, and in addition, there is an advantage that can prevent the formation of a frost band.

In the third defrosting operation, the third hot gas valve 98 is opened, and the first hot gas valve 96, the second hot gas valve 97, and the fourth hot gas valve 99 are blocked (closed). do. And the third expansion valve 53 is blocked (closed), and the first expansion valve 51, the second expansion valve 52, and the fourth expansion valve 54 are opened.

In the third defrosting operation, since the third hot gas valve 98 is opened, the compressed refrigerant (hot gas) flowing along the hot gas pipe 90 flows through the third branch pipe 93 through the third flow pipe. (43) can be introduced. At this time, since the third expansion valve 53 is in a closed state, the condensed refrigerant in the refrigerant passage 35 does not flow into the third flow tube 43 .

In addition, the compressed refrigerant (hot gas) introduced into the third flow pipe 43 is a first variable valve 106 installed in the first variable flow path 101 and a second variable valve 106 installed in the second variable flow path 102 . Due to the variable valve 107 , even if a portion flows into the third variable flow path 103 , no backflow into the first flow pipe 41 or the second flow pipe 42 is performed.

Therefore, all of the compressed refrigerant (hot gas) introduced into the third flow pipe 43 may be introduced into the third heat exchanger 63, and as described above, the third heat exchanger 63 through the high-temperature compressed refrigerant. of defrost can be performed.

The controller 200 may perform the third defrosting operation until a set predetermined time (T3+Toverlap) has elapsed. Here, the set predetermined time (T3+Toverlap) may be referred to as a third driving time. Specifically, the third defrost operation may be performed for a time obtained by subtracting the second defrost time T2 from the third operation time (T3+Toverlap).

In detail, the third operation time (T3+Toverlap) is a third defrost time (T3) determined by detecting a temperature change of the third heat exchanger 63 through the third temperature sensor 78 and the overlap operation time ( Toverlap) can be defined as the added time (T3+Toverlap).

That is, the control unit 200 may perform the third defrosting operation until the third operation time (T3+Toverlap) elapses.

Meanwhile, the third defrost operation may be performed for a longer time than the second defrost operation. That is, since the overlap operation time Toverlap is set to be the same, the difference between the third defrost time T3 and the second defrost time T2 may be set to be greater than the second defrost time T2. According to this, there is an advantage in that it is possible to effectively remove the frost formation that may occur as the water generated during the defrosting process of the heat exchanger located on the upper side flows down and accumulates.

When the third operation time (T3+Toverlap) has elapsed, the control unit 200 may end the third defrosting operation. At this time, the control unit 200 controls the third hot gas valve 98 to be switched to a blocked (closed) state and to switch the third expansion valve 53 to an open state, whereby the third heat exchanger 63 is can again act as an evaporator.

Meanwhile, in the third defrosting operation, the first expansion valve 51 , the second expansion valve 52 and the fourth expansion valve 54 expand the refrigerant in the same manner as in the heating operation, so that the first heat exchanger ( 61), the refrigerant that has passed through the second heat exchanger 62 and the fourth heat exchanger 64 may be introduced into the header 80 in an evaporated state. Accordingly, even when the third defrosting operation is performed, indoor heating can be continuously provided and, as described above, 75% of the heat exchangers 60 and 64 can maintain the operation of the evaporator.

Referring to FIG. 5D , the fourth defrosting operation may be defined as an operation in which frost is formed on the fourth heat exchanger 64 to perform defrosting.

The control unit 200 performs a fourth defrost operation when it is determined that the third defrost time T3 has elapsed or it is determined that frost has formed on the fourth heat exchanger 64 based on the result detected by the implantation detection means. can do.

Here, after the third defrost time T3 has elapsed, the third defrost operation and the fourth operation may be simultaneously performed during the overlap operation time (Toverlap). According to this, as described above, it is possible to prevent the melted flowing water from being implanted in the lower heat exchanger, and in addition, there is an advantage that can prevent the formation of a frost band.

In the fourth defrosting operation, the fourth hot gas valve 99 is opened, and the first hot gas valve 96, the second hot gas valve 97, and the third hot gas valve 98 are blocked (closed). do. And the fourth expansion valve 54 is blocked (closed), and the first expansion valve 51, the second expansion valve 52, and the third expansion valve 53 are opened.

In the fourth defrosting operation, since the fourth hot gas valve 99 is opened, the compressed refrigerant (hot gas) flowing along the hot gas pipe 90 flows through the fourth branch pipe 94 through the fourth flow pipe. (44) can be introduced. At this time, since the fourth expansion valve 54 is in a closed state, the condensed refrigerant in the refrigerant passage 35 does not flow into the fourth flow tube 44 . In addition, defrosting of the fourth heat exchanger 64 through the high-temperature compressed refrigerant may be performed.

The control unit 200 may perform a fourth defrosting operation until a set predetermined time T4 has elapsed. Here, the set predetermined time T4 may be referred to as a fourth driving time. Specifically, the fourth defrost operation may be performed for a time obtained by subtracting the third defrost time T3 from the fourth operation time T4.

In detail, the fourth operating time T4 may be defined as a fourth defrosting time T4 determined by detecting a temperature change of the fourth heat exchanger 64 through the fourth temperature sensor 79 . In this embodiment, since the fourth heat exchanger 64 is a heat exchanger provided at the lowermost stage, it will be apparent that overlap operation time (Toverlap) is unnecessary. Therefore, it can be understood that the operation time T4 for the lowest heat exchanger 64 is the same as the defrost time T4.

That is, the controller 200 may perform the fourth defrosting operation until the fourth operation time T4 elapses.

Meanwhile, the fourth defrosting operation may be performed for a longer time than the third defrosting operation. That is, since the overlap operation time (Toverlap) is set to be the same, the difference between the fourth defrost time T4 and the third defrost time T3 may be set to be greater than the third defrost time T3. According to this, there is an advantage in that it is possible to effectively remove the frost formation that may occur as the water generated during the defrosting process of the heat exchanger located on the upper side flows down and accumulates.

That is, the control unit 200 may increase the defrosting operation execution time as the heat exchanger located at the lower side increases.

The controller 200 may end the fourth defrosting operation when the fourth operation time T4 has elapsed. At this time, the control unit 200 controls the fourth hot gas valve 99 to be switched to a blocked (closed) state and the fourth expansion valve 54 to an open state, whereby the fourth heat exchanger 64 is can again act as an evaporator.

When the fourth heat exchanger 64 operates as an evaporator again, it can be understood that the defrosting operation returns to the normal heating operation.

Meanwhile, in the fourth defrosting operation, the first expansion valve 51, the second expansion valve 52 and the third expansion valve 53 expand the refrigerant in the same manner as in the heating operation, so that the first heat exchanger ( 61), the refrigerant that has passed through the second heat exchanger 62 and the third heat exchanger 63 may be introduced into the header 80 in an evaporated state. Accordingly, even when the fourth defrosting operation is performed, indoor heating can be continuously provided and, as described above, 75% of the heat exchangers 60 and 64 can maintain the operation of the evaporator.

According to an embodiment of the present invention, in order to solve the problem that water flowing in the defrosting process of the heat exchanger located at the upper side is implanted in the heat exchanger located at the lower side and the problem that a frost band is formed between the heat exchangers, the control unit 200 may cause the defrosting operation of the heat exchanger located on the lower side to be sequentially performed when the defrosting operation of the upper side heat exchanger is performed. And, when the defrosting operation of the heat exchanger located at the lowermost stage is finished, the water accumulated in the lower part of the outdoor heat exchanger is finally drained, so that it can be completely removed from the outdoor heat exchangers 60 and 64 .

In addition, in order to solve the problem that water flowing in the defrosting process of the heat exchanger located at the upper side is implanted in the heat exchanger located at the lower side and the problem that a frost band is formed between the heat exchangers, the control unit 200 is configured to defrost the upper heat exchanger. The operation and the defrosting operation of the lower side heat exchanger can be performed simultaneously for a certain period of time.

Here, the predetermined time may be understood as the overlap operation time (Toverlap). For example, the overlap operation time (Toverlap) may be set to 30 seconds.

In summary, when the defrosting operation for the nth heat exchanger is performed, the control unit 200 controls the n+1th heat exchanger located below the nth heat exchanger according to the lapse of a predetermined time (T1, T2, T3). It is possible to control the defrosting operation to be sequentially performed.

In addition, the control unit 200 terminates the defrosting operation of the n-th heat exchanger when the time in which the overlap operation time (Toverlap) is added to the predetermined time (T1, T2, T3) elapses and returns to the heating operation. can be controlled However, the defrosting operation of the lower heat exchanger 64 located at the lowermost end of the outdoor heat exchangers 60 and 64 may be immediately terminated when a predetermined time T4 has elapsed and return to the heating operation.

Here, n means a natural number equal to or less than the total number of heat exchangers (A) provided in the outdoor heat exchangers 60 and 64 .

A detailed description related thereto will be described through the description of the control method for the defrosting operation of the air conditioner according to the embodiment of the present invention with reference to FIGS. 6 and 7 .

6 is a flowchart illustrating a control method for a defrosting operation of an air conditioner according to an embodiment of the present invention, and FIG. 7 is a hot gas over time for a defrosting operation of the air conditioner according to an embodiment of the present invention. It is a graph showing the opening/closing operation of the valve and the amount of implantation of the heat exchanger.

As described above, when the heating operation is performed, since the outdoor heat exchangers 60 and 64 operate as evaporators, frost may occur.

6 and 7 , the controller 200 may determine whether the current operation of the air conditioner is a heating operation. (S1)

And when it is determined that the heating operation is performed, the control unit 200 may determine whether the outdoor heat exchangers 60 and 64 are implanted based on the information sensed by the implantation detecting means. (S2)

In more detail, the control unit 200 may determine whether the outdoor heat exchangers 60 and 64 are implanted based on the detection information of the outdoor temperature sensor and the first to fourth temperature sensors 76, 77, 78, and 79. there is. For example, if the temperature detected by the outdoor temperature sensor and the third temperature sensor 78 corresponds to a temperature at which it can be determined that frost has occurred by the table stored in advance, the control unit 200 may control the third heat exchanger. It can be judged that frost was implanted in (63).

If it is determined that an implantation has occurred in any one of the plurality of heat exchangers 61, 62, 63, and 64 stacked in multiple stages, the control unit 200 performs a defrosting operation of the n-th heat exchanger in which the implantation occurred. It can be done. (S3)

Here, n may be defined as any one of natural numbers having a value equal to or less than the total number of heat exchangers (A).

For example, if it is determined that the first heat exchanger 61 has an implantation, the control unit 200 may perform the above-described first defrosting operation. Similarly, if it is determined that the second heat exchanger 62 has an implantation, the control unit 200 may perform the above-described second defrosting operation.

In the plurality of heat exchangers stacked in multiple stages, the uppermost heat exchanger is defined as the first heat exchanger 61, and the number of the heat exchangers may be defined such that the number is sequentially increased toward the lower side. For example, the second heat exchanger 62 , the third heat exchanger 63 , and the fourth heat exchanger 64 may be sequentially positioned downward from the first heat exchanger 61 .

On the other hand, when it is determined that an implantation occurs in a plurality of heat exchangers among the heat exchangers 61, 62, 63, and 64, the control unit 200 performs a defrosting operation of the heat exchanger located at the uppermost position among the heat exchangers in which the implantation has occurred. can be controlled to be performed.

The control unit 200 may open an nth hot gas valve for the defrosting operation of the nth heat exchanger in which the conception has occurred, and block (close) the nth expansion valve. (S4)

For example, when an implantation occurs in the second heat exchanger 62 and the second defrosting operation is performed, the control unit 200 opens the second hot gas valve 97 and closes the second expansion valve 52 . can be blocked Accordingly, the compressed refrigerant 90 introduced into the hot gas pipe 90 may flow to the second heat exchanger 62 along the second branch pipe 92 to perform defrosting.

The control unit 200 may detect a defrosting operation execution time t of the nth heat exchanger. And the control unit 200 may determine whether the execution time (t) has elapsed a preset defrost time (Tn). (S5)

Here, the preset defrost time Tn may be understood as any one of the first to fourth defrost times T1, T2, T3, and T4.

If it is determined that the execution time t has elapsed the defrost time Tn, the control unit 200 may determine whether the heat exchanger in which the current defrosting operation is performed corresponds to the lowest heat exchanger (S6).

That is, if the value of n is equal to the value (A) of the total number of heat exchangers in the n-th heat exchanger in which the defrosting operation is performed, the heat exchanger in which the current defrosting operation is performed is a heat exchanger located at the bottom of the outdoor heat exchangers 60 and 64. can be judged as

If the heat exchanger on which the defrosting operation is currently performed is not a heat exchanger located at the lowermost stage, the control unit 200 may perform a defrosting operation of the n+1th heat exchanger located below the nth heat exchanger (S7).

For example, when the current defrosting operation of the second heat exchanger 62 is performed, the control unit 200 controls the third heat exchanger 63 when the execution time t elapses the second defrosting time T2. ) can start the defrost operation. That is, the third defrost operation can be started.

When the defrosting operation of the n+1 heat exchanger is performed, the control unit 200 may open the n+1th hot gas valve and block (close) the n+1th expansion valve (S8).

For example, when the defrosting operation of the third heat exchanger 63 starts, the controller 200 may open the third hot gas valve 98 and block the third expansion valve 53 .

In addition, the control unit 200 may simultaneously perform the defrosting operation of the nth heat exchanger and the defrosting operation of the n+1th heat exchanger during the overlap operation time (Toverlap).

That is, the control unit 200 can determine whether the execution time (t) has elapsed from the defrost time (Tn) to the operation time (Tn+Toverlap) plus the overlap operation time (Toverlap). (S9)

For example, when the defrosting operation of the third heat exchanger 63 is performed, the control unit 200 may determine whether the execution time t has elapsed the second operation time T2 + Tovelap. there is.

When the execution time (t) elapses the operation time (Tn+Toverlap), the control unit 200 may end the defrosting operation of the n-th heat exchanger and return to operate as an evaporator (S10).

That is, the control unit 200 may block (close) the nth hot gas valve and control the nth expansion valve to be opened. (S11)

For example, when the execution time t elapses the second operation time (T2+Toverlap), the control unit 200 terminates the defrosting operation of the second heat exchanger 62 and returns to the heating operation. can do it In this case, the control unit 200 may change the state of the valve so that the second hot gas valve 97 is shut off, and at the same time change the state of the valve so that the second expansion valve 52 is opened. Accordingly, the defrosting operation of the second heat bridge 62 is terminated, and the heating operation can be performed again by operating as an evaporator.

When the nth heat exchanger returns to the evaporator, the control unit 200 may newly define the value of n as a value of n+1. (S12) And the defrost time Tn for which the execution time t is preset The process may be repeated by returning to step S5 of determining whether or not has elapsed.

More specifically, when the nth heat exchanger returns to the evaporator, the control unit 200 controls the defrost time (t) of the defrost operation of the n+1th heat exchanger located below the nth heat exchanger for a preset defrost time ( It can be determined whether Tn+1) has elapsed. For example, when the second heat exchanger 62 is returned to operate as an evaporator, the control unit 200 determines that the defrost operation execution time t of the third heat exchanger 63 exceeds the third defrost time T3. It can be judged whether Also, as described above, the controller 200 may start a defrosting operation of the fourth heat exchanger 64 if it is not the lowest heat exchanger.

On the other hand, if it is determined that the n-th heat exchanger on which the current defrosting operation is performed corresponds to the lowest heat exchanger, the control unit 200 does not wait for the lapse of the overlap operation time (Toverlap) to immediately terminate the defrosting operation of the n-th heat exchanger. (S13)

Specifically, if the value of n is the same as the value of the total number of heat exchangers (A), the heat exchanger in which the defrosting operation is currently performed may be determined to be the heat exchanger located at the lowermost stage. As described above, the heat exchanger located at the lowermost stage does not require overlap operation time (Toverlap). Accordingly, when the defrost operation execution time t of the n-th heat exchanger elapses a preset defrost time Tn, the control unit 200 may control the defrosting operation to immediately end and return to the evaporator.

When the defrosting operation is terminated as the nth heat exchanger is a heat exchanger located at the lowermost stage, the control unit 200 may switch the nth hot gas valve to a blocked (closed) state and switch the nth expansion valve to an open state. .(S14)

For example, referring to FIG. 5D , the fourth heat exchanger 64 is a heat exchanger located at the lowermost stage. Therefore, when the defrosting operation of the fourth heat exchanger 64 is performed, the control unit 200 ends the defrosting operation of the fourth heat exchanger 64 when the fourth defrosting time T4 has elapsed, and the evaporator can be returned to At this time, the control unit 200 switches the fourth hot gas valve 99 to the shut-off state and switches the fourth expansion valve 54 to the open state so that the fourth heat exchanger 64 operates as an evaporator. can be controlled to do so.

When the defrosting operation of the nth heat exchanger located at the lowermost stage is finished, all the heat exchangers operate as evaporators, so that the air conditioner can completely return to the heating operation again (S15).

As such, the defrosting of the outdoor heat exchangers 60 and 64 according to the embodiment of the present invention may be sequentially defrosted from the heat exchanger located at the upper side to the lower side. Therefore, water that melts and flows in the defrosting process can be directed to the lowermost end of the outdoor heat exchangers 60 and 64 without being deposited on the heat exchanger located at the lower side. And the water can be easily removed from the outdoor heat exchanger through drainage.

In addition, when the outdoor heat exchanger is divided into four heat exchangers, there is an advantage in that the heating capacity can be continuously maintained by 75% or more even in the case of a defrosting operation. Therefore, even when the defrosting operation is performed, it is possible to minimize the phenomenon that the temperature of the room decreases. In addition, there is an advantage of quickly returning to the normal range of the heating cycle when returning to heating operation.

In addition, during the overlap operation time (Toverlap), since the heat exchangers located on the upper side and the lower side perform the defrosting operation at the same time, there is an advantage in that the temperature difference between the heat exchangers is reduced to prevent the formation of a frost band.

In addition, since the defrost operation time is differentiated to increase as the heat exchanger located below it, there is an advantage in that it is possible to easily remove the frost formed due to the water accumulated in the lower side.

10: compressor 30: indoor unit
60: upper outdoor heat exchanger 64: lower outdoor heat exchanger
80: header 90: hot gas pipe

Claims (17)

a compressor that compresses the refrigerant;
an indoor unit provided with an indoor heat exchanger;
an outdoor heat exchanger in which a plurality of heat exchangers are stacked in multiple stages;
a flow pipe extending from the indoor unit to the plurality of heat exchangers;
an implantation detection means for detecting whether frost is formed on the plurality of heat exchangers; and
A control unit for controlling the defrosting operation of each of the plurality of heat exchangers based on the information sensed by the implantation detecting means,
The control unit is
When the defrosting operation of any one of the plurality of heat exchangers is performed, the defrosting operation of the other heat exchangers is sequentially performed downward of the one heat exchanger,
The air conditioner according to claim 1, wherein the defrosting operation execution time is increased so that the heat exchanger is located on the lower side. The method of claim 1,
The control unit is
The air conditioner according to claim 1, wherein a defrosting operation of a heat exchanger located at an uppermost side among the plurality of heat exchangers is performed when an implantation is detected in the plurality of heat exchangers. delete The method of claim 1,
The implantation detection means,
outdoor temperature sensor; and
An air conditioner including a temperature sensor provided in the plurality of heat exchangers. The method of claim 1,
a discharge pipe provided on the discharge side of the compressor;
a hot gas pipe branching from the discharge pipe;
a branch pipe extending from the hot gas pipe to the flow pipe; and
The air conditioner further comprising a hot gas valve installed in the branch pipe. 6. The method of claim 5,
The plurality of heat exchangers are air conditioners, characterized in that the defrosting is made by the refrigerant flowing through the hot gas pipe. 6. The method of claim 5,
Further comprising an expansion valve installed on the flow pipe,
The branch pipe,
The air conditioner according to claim 1, wherein the flow pipe is connected between the expansion valve and the outdoor heat exchanger. The method of claim 1,
header;
a variable flow path branching from the flow pipe and extending to the header; and
The air conditioner further comprising a blocking unit installed in the variable flow path. 9. The method of claim 8,
The plurality of heat exchangers,
a first heat exchanger located at the top;
a second heat exchanger located below the first heat exchanger;
a third heat exchanger located below the second heat exchanger; and
An air conditioner including a fourth heat exchanger located at the bottom. 10. The method of claim 9,
The outdoor heat exchanger is
The upper outdoor heat exchanger located on the high wind speed side and
It includes a lower outdoor heat exchanger located on the low wind speed side,
The upper outdoor heat exchanger,
and the first to third heat exchangers. 11. The method of claim 10,
The variable flow path is
The air conditioner according to claim 1, wherein the air conditioner is branched from a flow pipe extending to the upper outdoor heat exchanger. The method of claim 1,
The control unit is
The air conditioner according to claim 1, wherein the one heat exchanger and the heat exchanger located below the one heat exchanger are controlled to simultaneously perform a defrosting operation for a preset overlap operation time (Toverlap). A compressor, an indoor unit, an outdoor heat exchanger in which a plurality of heat exchangers are stacked in multiple stages, a plurality of flow pipes extending from the indoor unit to the plurality of heat exchangers, an expansion valve installed in the flow pipe, and a defrosting operation of each of the plurality of heat exchangers An air conditioner comprising a control unit, comprising:
judging whether the plurality of heat exchangers are implanted on the basis of the information sensed by the implantation detection means;
starting a defrosting of an n-th heat exchanger in which an implantation has occurred among the plurality of heat exchangers;
determining whether a defrosting execution time (t) of the nth heat exchanger elapses a preset defrosting time (Tn); and
and starting the defrosting of an n+1th heat exchanger located below the nth heat exchanger when the defrosting execution time t elapses the defrosting time Tn. 14. The method of claim 13,
Further comprising the step of determining whether the defrost execution time (t) has elapsed an operation time (Tn + Toverlap) added to the defrost time (Tn) by a preset overlap operation time (Toverlap),
During the overlap operation time, the air conditioner control method, characterized in that the defrosting of the nth heat exchanger and the n+1th heat exchanger is simultaneously performed. 15. The method of claim 14,
The air conditioner control method according to claim 1, wherein the defrosting of the nth heat exchanger is terminated when the defrosting execution time t elapses the operation time (Tn+Toverlap). 14. The method of claim 13,
When the defrost time (Tn) has elapsed, further comprising the step of determining whether the nth heat exchanger corresponds to the lowest heat exchanger,
The control unit is
When the nth heat exchanger corresponds to the lowest heat exchanger, the air conditioner control method characterized in that the defrosting of the nth heat exchanger is terminated. 14. The method of claim 13,
The control unit is
The air conditioner control method according to claim 1, wherein the defrosting operation time of the n+1th heat exchanger is controlled to be longer than the defrosting operation time of the nth heat exchanger.

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