Air Conditioning Equipment

Abstract

The air conditioning apparatus of this embodiment includes an outdoor unit through which a refrigerant circulates; an indoor unit through which water circulates; and a heat exchanger that connects the outdoor unit and the indoor unit and exchanges heat between the refrigerant and the water, the heat exchanger including a first heat exchanger and a second heat exchanger, a first refrigerant piping and a second refrigerant piping connected to the first heat exchanger and the second heat exchanger, respectively, an expansion valve provided in the second refrigerant piping, a bypass piping that connects the second refrigerant piping of the first heat exchanger and the first refrigerant piping of the second heat exchanger, and a bypass valve provided in the bypass piping.

Description

[Technical field]

[0001] [1] This specification relates to an air conditioning apparatus. [Background technology]

[0002] [2] An air conditioner is a device for maintaining the air in a given space at an optimal state depending on the application and purpose. In general, the air conditioner includes a compressor, a condenser, an expansion device, and an evaporator, and operates a refrigeration cycle that performs the processes of compression, condensation, expansion, and evaporation of a refrigerant to cool or heat the given space.

[0003] [3] The predetermined space may be variously proposed depending on the place where the air conditioner is used. For example, the air conditioner may be used in a home or an office.

[0004] [4] When the air conditioner is in cooling operation, the outdoor heat exchanger in the outdoor unit functions as a condenser, and the indoor heat exchanger in the indoor unit functions as an evaporator. On the other hand, when the air conditioner is in heating operation, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator.

[0005] [5] Recently, environmental regulatory policies have led to restrictions on the types of refrigerants that can be used in air conditioning systems, resulting in a trend toward reducing the amount of refrigerant used.

[0006] [6] In order to reduce the amount of refrigerant used, a technique has been proposed for cooling or heating by exchanging heat between a refrigerant and a predetermined fluid. In one example, the predetermined fluid may include water.

[0007] [7] The following prior art documents are disclosed in relation to a system for cooling or heating through heat exchange between a refrigerant and water.

[0008] [8] 1. Publication number (publication date): Korean Patent Publication 10-2013-0127531 (November 22, 2013) [9] 2. Title of invention: Plate heat exchanger and heat pump device

[0009]

[10] According to the above-mentioned prior art, a plate-shaped heat exchanger can generate heat through heat exchange between a refrigerant and water to provide heating and cooling, hot water, or cold water. However, there is a problem in that the refrigerant flow path is formed in the same way regardless of whether the plate-shaped heat exchanger functions as a condenser or an evaporator, resulting in a decrease in heat exchange performance.

[0010]

[11] That is, when the plate-shaped heat exchanger functions as a condenser, it is advantageous to reduce the number of refrigerant paths and make the paths longer in order to improve condensation performance. On the other hand, when the plate-shaped heat exchanger functions as an evaporator, it is advantageous to increase the number of refrigerant paths and make the paths shorter in order to prevent pressure loss, i.e., a drop in evaporation pressure.

[0011]

[12] However, according to the above-mentioned prior art, the configuration of the refrigerant flow path in a plate-type heat exchanger is fixed regardless of whether it functions as a condenser or an evaporator, which results in a problem of reduced heat exchange performance. Summary of the Invention [Problem to be solved by the invention]

[0012]

[13] This embodiment provides an air conditioner capable of improving performance by varying the refrigerant flow path in the heat exchanger during cooling operation or heating operation.

[0013]

[14] In this embodiment, when multiple heat exchangers provided in a heat exchanger device act as evaporators during cooling operation, the refrigerant branches off and flows into the multiple heat exchangers, thereby increasing the number of refrigerant flow paths and shortening their lengths (parallel connection of heat exchangers), thereby providing an air conditioning apparatus that can prevent a drop in evaporation pressure.

[0014]

[15] This embodiment provides an air conditioning apparatus in which, during heating operation, when the multiple heat exchangers function as condensers, the refrigerant passes through the multiple heat exchangers in sequence, thereby increasing the length of the refrigerant flow path and reducing the number of heat exchangers (series connection of the heat exchangers), thereby improving the condensation performance in the heat exchangers. [Means for solving the problem]

[0015]

[16] An air conditioning apparatus according to one embodiment includes an outdoor unit through which a refrigerant circulates; a number of indoor units through which water circulates; and a heat exchange device connecting the outdoor unit and the number of indoor units and performing heat exchange between the refrigerant and the water, wherein the heat exchange device includes a number of heat exchangers each including a refrigerant flow path and a water flow path, and a refrigerant flow path varying means for varying the refrigerant flow path so that the number of heat exchangers operates as either an evaporator or a condenser.

[0016]

[17] The refrigerant flow path varying means of the present embodiment may vary the refrigerant flow path so that the refrigerant flows in parallel through the multiple heat exchangers during cooling operation of the indoor unit.

[0017]

[18] By using the refrigerant flow path varying means of the present embodiment, the flow path of the refrigerant may be varied so that the refrigerant flows sequentially through multiple heat exchangers during heating operation of the indoor unit.

[0018]

[19] The multiple heat exchangers may include a first heat exchanger and a second heat exchanger.

[0019]

[20] The heat exchange device may include a first refrigerant piping and a second refrigerant piping connected to the first heat exchanger and the second heat exchanger, respectively, and an expansion valve provided in the second refrigerant piping.

[0020]

[21] The refrigerant flow path varying means may include a bypass piping connecting a second refrigerant piping of the first heat exchanger and a first refrigerant piping of the second heat exchanger, and a bypass valve provided in the bypass piping.

[0021]

[22] In this embodiment, the bypass piping may be connected to a portion of a second refrigerant piping of the first heat exchanger between the expansion valve and the refrigerant flow path of the first heat exchanger.

[0022]

[23] The refrigerant flow path varying means may further include a check valve that blocks the refrigerant in the first refrigerant piping of the first heat exchanger from flowing to the first refrigerant piping of the second heat exchanger and allows the refrigerant in the first refrigerant piping of the second heat exchanger to flow to the first refrigerant piping of the first heat exchanger.

[0023]

[24] During cooling operation of the indoor unit, the expansion valve of the second refrigerant pipe may be opened and the bypass valve may be closed. In this case, the refrigerant discharged from the outdoor unit may flow to each of the heat exchangers via the second refrigerant pipe of each of the heat exchangers and then discharged to the first refrigerant pipe of each of the heat exchangers.

[0024]

[25] During cooling operation of the indoor unit, in order to use some of the first and second heat exchangers, the expansion valves corresponding to the heat exchangers to be used may be opened, the expansion valves corresponding to the heat exchangers not being used may be closed, and the bypass valve may be closed.

[0025]

[26] During heating operation of the indoor unit, an expansion valve provided in the second refrigerant pipe of the first heat exchanger may be closed, an expansion valve provided in the second refrigerant pipe of the second heat exchanger may be opened, and the bypass valve may be opened. In this case, the refrigerant that has flowed through the first heat exchanger may flow through the second heat exchanger.

[0026]

[27] During heating operation of the indoor unit, in order to use some of the first and second heat exchangers, an expansion valve provided in the second refrigerant piping of the first heat exchanger may be opened, an expansion valve provided in the second refrigerant piping of the second heat exchanger may be closed, and the bypass valve may be closed.

[0027]

[28] The air conditioning apparatus may further include a water flow path varying means for varying the flow path of water flowing to the multiple heat exchangers so that the multiple indoor units operate in either heating operation or cooling operation.

[0028]

[29] The water flow path varying means can vary the water flow path so that water flows to the heat exchanger acting as a condenser when the indoor unit is in heating operation, and so that water flows to the heat exchanger acting as an evaporator when the indoor unit is in cooling operation.

[0029]

[30] An air conditioning apparatus according to another aspect includes an outdoor unit through which a refrigerant circulates; an indoor unit through which water circulates; and a heat exchange device connecting the outdoor unit and the indoor unit and performing heat exchange between the refrigerant and the water, wherein the heat exchange device may include a first heat exchanger and a second heat exchanger, a first refrigerant piping and a second refrigerant piping connected to the first heat exchanger and the second heat exchanger, respectively, an expansion valve provided in the second refrigerant piping, a bypass piping connecting the second refrigerant piping of the first heat exchanger and the first refrigerant piping of the second heat exchanger, and a bypass valve provided in the bypass piping.

[0030]

[31] The first heat exchanger may include a refrigerant flow path through which a refrigerant flows, and the bypass piping may be connected to a portion of a second refrigerant piping of the first heat exchanger between the expansion valve and the refrigerant flow path.

[0031]

[32] The system may further include a check valve provided in a pipe connecting a first refrigerant pipe of the first heat exchanger and a first refrigerant pipe of the second heat exchanger, or in the first refrigerant pipe of the second heat exchanger.

[0032]

[33] The check valve can block refrigerant in a first refrigerant piping of a first heat exchanger from flowing to the first refrigerant piping of the second heat exchanger, and allow refrigerant in the first refrigerant piping of the second heat exchanger to flow to the first refrigerant piping of the first heat exchanger.

[0033]

[34] During cooling operation of the indoor unit, the expansion valve of the second refrigerant piping may be opened and the bypass valve may be closed so that the refrigerant discharged from the outdoor unit flows to each heat exchanger via the second refrigerant piping of each heat exchanger and is then discharged to the first refrigerant piping of each heat exchanger.

[0034]

[35] During cooling operation of the indoor unit, refrigerant that has passed through the second heat exchanger can pass through the check valve.

[0035]

[36] During cooling operation of the indoor unit, in order to use some of the first and second heat exchangers, the expansion valves corresponding to the heat exchangers to be used may be opened, the expansion valves corresponding to the heat exchangers not being used may be closed, and the bypass valve may be closed.

[0036]

[37] When the second heat exchanger is used and the first heat exchanger is not used, the refrigerant that flows through the second heat exchanger can pass through the check valve.

[0037]

[38] During heating operation of the indoor unit, an expansion valve provided in a second refrigerant piping of the first heat exchanger may be closed, an expansion valve provided in a second refrigerant piping of the second heat exchanger may be opened, and the bypass valve may be opened so that the refrigerant that has flowed through the first heat exchanger flows through the second heat exchanger.

[0038]

[39] During heating operation of the indoor unit, in order to use some of the first and second heat exchangers, an expansion valve provided in the second refrigerant piping of the first heat exchanger may be opened, an expansion valve provided in the second refrigerant piping of the second heat exchanger may be closed, and the bypass valve may be closed.

[0039]

[40] Each of the heat exchangers includes a water flow path through which water flows to exchange heat with a refrigerant, and the water that flows through the water flow path can flow to the indoor unit.

[0040]

[41] The air conditioning apparatus may further include a first outdoor unit connecting pipe connected to the outdoor unit and through which a high-pressure gas-phase refrigerant flows, a second outdoor unit connecting pipe connected to the outdoor unit and through which a low-pressure gas-phase refrigerant flows, and a third outdoor unit connecting pipe connected to the outdoor unit and through which a liquid refrigerant flows.

[0041]

[42] The air conditioning apparatus may further include a branch pipe connected to the first outdoor unit connecting pipe, a branch pipe connected to the second outdoor unit connecting pipe, and a common air pipe connecting the branch pipes to each other.

[0042]

[43] The common air duct may be connected to first refrigerant pipes of the first and second heat exchangers. The third outdoor unit connecting pipe may be connected to second refrigerant pipes of the first and second heat exchangers.

[0043]

[44] The system may further include a valve provided in each of the branch pipes.

[0044]

[45] Specific details for one or more embodiments are disclosed in the accompanying drawings and detailed description below. Other features will be apparent from the description, drawings, and claims. Effect of the Invention

[0045]

[46] According to this embodiment, the performance can be improved by varying the refrigerant flow path in the heat exchanger during cooling or heating operation.

[0046]

[47] In particular, during cooling operation, when multiple heat exchangers in a heat exchanger unit function as evaporators, the refrigerant branches off and flows into multiple heat exchangers, increasing the number of refrigerant flow paths. By shortening the length of the flow paths (parallel connection of heat exchangers), a decrease in evaporation pressure can be prevented.

[0047]

[48] ​​On the other hand, during heating operation, when multiple heat exchangers function as condensers, the refrigerant passes through the multiple heat exchangers in sequence, increasing the length of the refrigerant flow path and reducing the number of heat exchangers (series connection), thereby improving the condensation performance of the heat exchangers.

[0048]

[49] In addition, when the outdoor unit and the heat exchanger are connected by three pipes, cooling and heating operations can be performed simultaneously, which has the advantage that some of the indoor units can be operated in heating operation while the other indoor units are operated in cooling operation. [Brief description of the drawings]

[0049] [Figure 1]

[50] Figure 1 is a schematic diagram showing the configuration of an air-conditioning apparatus according to one embodiment of the present invention. [Diagram 2]

[51] Figure 2 is a cycle diagram showing the configuration of an air conditioning apparatus according to one embodiment of the present invention. [Diagram 3]

[52] FIG. 3 is a cycle diagram showing the flow of refrigerant and water in a heat exchanger during cooling operation of an air conditioner according to one embodiment of the present invention. [Figure 4]

[53] FIG. 4 is a cycle diagram showing the flow of refrigerant and water in a heat exchanger during heating operation of an air conditioner according to one embodiment of the present invention. [Diagram 5]

[54] Figure 5 is a cycle diagram showing the flow of refrigerant and water when only a portion of multiple heat exchangers are used during heating operation of an air conditioner according to one embodiment of the present invention. [Figure 6]

[55] FIG. 6 is a cycle diagram showing the flow of refrigerant and water in an air conditioner when some of the indoor units according to one embodiment of the present invention are in heating operation and the other are in cooling operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050]

[56] Some embodiments of the present invention will be described in detail below with reference to the illustrative drawings. In assigning reference numerals to components in each drawing, it should be noted that the same components are assigned the same numerals as much as possible even if they are displayed in different drawings. In addition, when describing the embodiments of the present invention, if it is determined that a detailed description of such well-known configurations or functions would hinder the understanding of the embodiments of the present invention, the detailed description will be omitted.

[0051]

[57] In addition, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of the embodiments of the present invention. Such terms are merely used to distinguish the components from other components, and do not limit the nature, order, or sequence of the components. When a component is described as being "coupled," "connected," or "connected" to another component, it should be understood that the component may be directly coupled or connected to the other component, but that other components may also be "coupled," "connected," or "connected" between each component.

[0052]

[58] FIG. 1 is a schematic diagram showing the configuration of an air conditioning apparatus according to one embodiment of the present invention, and FIG. 2 is a cycle diagram showing the configuration of an air conditioning apparatus according to one embodiment of the present invention.

[0053]

[59] Referring to Figures 1 and 2, an air conditioning apparatus 1 according to one embodiment of the present invention may include an outdoor unit 10, an indoor unit 50, and a heat exchange device 100 connected to the outdoor unit 10 and the indoor unit 50.

[0054]

[60] The outdoor unit 10 and the heat exchange device 100 may be fluidly connected by a first fluid. As an example, the first fluid may include a refrigerant.

[0055]

[61] The refrigerant can flow through a refrigerant-side passage of a heat exchanger provided in the heat exchange device 100 and the outdoor unit 10.

[0056]

[62] The outdoor unit 10 may include a compressor 11 and an outdoor heat exchanger 15.

[0057]

[63] An outdoor fan 16 is provided on one side of the outdoor heat exchanger 15 to blow outdoor air into the outdoor heat exchanger 15, and heat exchange may be performed between the outdoor air and the refrigerant in the outdoor heat exchanger 15 by driving the outdoor fan 16. The outdoor unit 10 may further include a main expansion valve 18 (EEV).

[0058]

[64] The air conditioner 1 may further include connection pipes 20, 25, 27 that connect the outdoor unit 10 and the heat exchanger 100.

[0059]

[65] The connecting pipes 20, 25, 27 may include a first outdoor unit connecting pipe 20 as a pipe (high pressure pipe) through which high pressure gas phase refrigerant flows, a second outdoor unit connecting pipe 25 as a pipe (low pressure pipe) through which low pressure gas phase refrigerant flows, and a third outdoor unit connecting pipe 27 as a liquid pipe through which liquid refrigerant flows.

[0060]

[66] That is, the outdoor unit 10 and the heat exchange device 100 have a “three-pipe connection structure”, and the refrigerant can circulate through the outdoor unit 10 and the heat exchange device 100 through three connection pipes 20, 25, and 27.

[0061]

[67] The heat exchange device 100 and the indoor unit 50 may be fluidly connected by a second fluid. As an example, the second fluid may include water.

[0062]

[68] The water can flow through a water-side flow passage of a heat exchanger provided in the heat exchange device 100 and the outdoor unit 10.

[0063]

[69] The heat exchanger device 100 can include multiple heat exchangers 140, 141, 142, 143. The heat exchangers can include, by way of example, plate heat exchangers.

[0064]

[70] The indoor unit 50 may include multiple indoor units 61, 62, 63, and 64. In this embodiment, it is clear that there is no limit to the number of the multiple indoor units 61, 62, 63, and 64. In FIG. 1, as an example, four indoor units 61, 62, 63, and 64 are illustrated as being connected to the heat exchange device 100.

[0065]

[71] The multiple indoor units 61, 62, 63, 64 may include a first indoor unit 61, a second indoor unit 62, a third indoor unit 63 and a second indoor unit 64.

[0066]

[72] The air conditioner 1 may further include pipes 30, 31, 32, and 33 connecting the heat exchanger 100 and the indoor unit 50.

[0067]

[73] The pipes 30, 31, 32, and 33 may include first to fourth indoor unit connecting pipes 30, 31, 32, and 33 that connect the heat exchange device 100 to the indoor units 61, 62, 63, and 64, respectively.

[0068]

[74] Water can circulate between the heat exchange device 100 and the indoor units 50 via the indoor unit connecting pipes 30, 31, 32, and 33. Of course, if the number of indoor units increases, the number of pipes connecting the heat exchange device 100 and the indoor units should increase.

[0069]

[75] With this configuration, the refrigerant circulating through the outdoor unit 10 and the heat exchange device 100 and the water circulating through the heat exchange device 100 and the indoor unit 50 exchange heat via heat exchangers 140, 141, 142, and 143 provided in the heat exchange device 100.

[0070]

[76] The water cooled or heated through the heat exchange can exchange heat with indoor heat exchangers 61a, 62a, 63a, and 64a provided in the indoor unit 50 to cool or heat the indoor space.

[0071]

[77] The number of heat exchangers 140, 141, 142, 143 may be the same as the number of indoor units 61, 62, 63, 64. Alternatively, two or more indoor units may be connected to one heat exchanger.

[0072]

[78] The heat exchange device 100 will now be described in detail.

[0073]

[79] The heat exchange device 100 may include first to fourth heat exchangers 140, 141, 142, and 143 that are fluidly connected to the indoor units 61, 62, 63, and 64, respectively.

[0074]

[80] The first to fourth heat exchangers 140, 141, 142, and 143 may be formed to have the same structure.

[0075]

[81] Each of the heat exchangers 140, 141, 142, and 143 may include, for example, a plate-shaped heat exchanger, and may be configured such that water flow paths and refrigerant flow paths are alternately stacked.

[0076]

[82] Each of the heat exchangers 140, 141, 142, 143 may include a refrigerant flow path 140a and a water flow path 140b.

[0077]

[83] The refrigerant flow path 140a is fluidly connected to the outdoor unit 10, so that refrigerant discharged from the outdoor unit 10 can flow into the refrigerant flow path 140a, and refrigerant that has passed through the refrigerant flow path 140a can flow into the outdoor unit 10.

[0078]

[84] Each water flow path 140b is connected to each indoor unit 61, 62, 63, 64, so that water discharged from each indoor unit 61, 62, 63, 64 flows into the water flow path 140b, and water that passes through the water flow path 140b can flow into each indoor unit 61, 62, 63, 64.

[0079]

[85] The heat exchange device 100 may include a first branch pipe 101a and a second branch pipe 102a branching off from the first outdoor unit connecting pipe 20. The first branch pipe 101a and the second branch pipe 102a may be provided with valves 101 and 102. However, it should be made clear that there is no limit to the number of branch pipes branching off from the first outdoor unit connecting pipe 20.

[0080]

[86] The heat exchanger 100 may include a third branch pipe 103a and a fourth branch pipe 104a branching off from the second outdoor unit connecting pipe 25. The third branch pipe 103a and the fourth branch pipe 104a may be provided with valves 103 and 104. However, it should be made clear that there is no limit to the number of branch pipes branching off from the second outdoor unit connecting pipe 25.

[0081]

[87] The heat exchange device 100 may include a first common air duct 111 to which the first branch pipe 101a and the third branch pipe 103a are connected, and a second common air duct 112 to which the second branch pipe 102a and the fourth branch pipe 104a are connected.

[0082]

[88] The first common trachea 111 and the second common trachea 112 can be in communication with each other.

[0083]

[89] Each of the heat exchangers 140, 141, 142, 143 may include a first refrigerant pipe 111a, 111b, 112a, 112b and a second refrigerant pipe 121, 122, 123, 124 that communicate with the refrigerant flow path 140a.

[0084]

[90] A first refrigerant pipe 111 a of the first heat exchanger 140 and a first refrigerant pipe 111 b of the second heat exchanger 141 may be in communication with the first common air pipe 111 .

[0085]

[91] A first check valve 132 may be provided in the piping connected between the first refrigerant piping 111a of the first heat exchanger 140 and the first refrigerant piping 111b of the second heat exchanger 141 in the first common air pipe 111 or in the first refrigerant piping 111b of the second heat exchanger 141.

[0086]

[92] The first check valve 132 allows the refrigerant in the first refrigerant pipe 111b of the second heat exchanger 141 to flow to the first refrigerant pipe 111a of the first heat exchanger 140. On the other hand, the first check valve 132 blocks the refrigerant in the first refrigerant pipe 111a of the first heat exchanger 140 from flowing to the first refrigerant pipe 111b of the second heat exchanger 141.

[0087]

[93] A first refrigerant pipe 112a of the third heat exchanger 142 and a first refrigerant pipe 112b of the fourth heat exchanger 143 may be in communication with the second common air pipe 112.

[0088]

[94] A second check valve 137 may be provided in the piping connected between the first refrigerant piping 112a of the third heat exchanger 142 and the first refrigerant piping 112b of the fourth heat exchanger 143 in the second common air pipe 112 or in the first refrigerant piping 112b of the fourth heat exchanger 143.

[0089]

[95] The second check valve 137 allows the refrigerant in the first refrigerant pipe 112b of the fourth heat exchanger 143 to flow to the first refrigerant pipe 112a of the third heat exchanger 142. On the other hand, the second check valve 137 blocks the refrigerant in the first refrigerant pipe 112a of the third heat exchanger 140 from flowing to the first refrigerant pipe 112b of the fourth heat exchanger 143.

[0090]

[96] The second refrigerant pipes 121, 122, 123, and 124 may be connected to the third outdoor unit connecting pipe 27.

[0091]

[97] The second refrigerant pipes 121, 122, 123, and 124 of the heat exchangers 140, 141, 142, and 143 may be provided with expansion valves 125, 126, 127, and 128.

[0092]

[98] Each of the expansion valves 125, 126, 127, and 128 may include, for example, an electronic expansion valve (EEV).

[0093]

[99] The electronic expansion valve can reduce the pressure of the refrigerant passing through the expansion valve by adjusting the opening degree. For example, when the expansion valve is fully open (full-open state), the refrigerant can pass through without being decompressed, and when the opening degree of the expansion valve is reduced, the refrigerant can be decompressed. The degree to which the refrigerant is decompressed increases as the opening degree is reduced.

[0094]

[0100] The second refrigerant pipe 121 of the first heat exchanger 140 and the first refrigerant pipe 111 b of the second heat exchanger 141 may be connected by a first bypass pipe 130 .

[0095]

[0101] The first bypass pipe 130 may be connected to a pipe between a first expansion valve 125 and a refrigerant passage 140a of the first heat exchanger 140 in the second refrigerant pipe 121. A first bypass valve 131 may be provided in the first bypass pipe 130.

[0096]

[0102] The second refrigerant pipe 123 of the third heat exchanger 142 and the first refrigerant pipe 112 b of the fourth heat exchanger 143 may be connected by a second bypass pipe 135 .

[0097]

[0103] The second bypass piping 135 may be connected to a piping between a third expansion valve 127 and a refrigerant flow path 140a of the third heat exchanger 142 in the second refrigerant piping 123. The second bypass piping 135 may be provided with a second bypass valve 136.

[0098]

[0104] Meanwhile, the heat exchange device 100 may further include heat exchanger inlet pipes 161a, 161b, 163a, and 163b and heat exchanger outlet pipes 162a, 162b, 164a, and 164b connected to the water flow paths 140b of the heat exchangers 140, 141, 142, and 143.

[0099]

[0105] A first heat exchanger inlet pipe 161a of the first heat exchanger 140 and a second heat exchanger inlet pipe 161b of the second heat exchanger 141 may branch off from a first common inlet pipe 161. A first pump 151 may be provided in the first common inlet pipe 161.

[0100]

[0106] A third heat exchanger inlet pipe 163a of the third heat exchanger 142 and a fourth heat exchanger inlet pipe 163b of the fourth heat exchanger 143 may branch off from a second common inlet pipe 163. A second pump 152 may be provided in the second common inlet pipe 163.

[0101]

[0107] The first heat exchanger discharge pipe 162 a of the first heat exchanger 140 and the second heat exchanger discharge pipe 162 b of the second heat exchanger 141 may be connected to a first common discharge pipe 162 .

[0102]

[0108] The third heat exchanger discharge pipe 164 a of the third heat exchanger 142 and the fourth heat exchanger discharge pipe 164 b of the fourth heat exchanger 143 may be connected to a second common discharge pipe 164 .

[0103]

[0109] A first manifold 181 may be connected to the first common inlet pipe 161. A second manifold 182 may be connected to the second common inlet pipe 163.

[0104]

[0110] A third manifold 183 may be connected to the first common discharge pipe 162. A fourth manifold 184 may be connected to the second common discharge pipe 164.

[0105]

[0111] The first manifold 181 may be connected to a first water discharge pipe 171 through which water discharged from the indoor heat exchangers 61a, 62a, 63a, and 64a flows.

[0106]

[0112] The second manifold 182 may be connected to a second water discharge pipe 172 through which water discharged from each of the indoor heat exchangers 61a, 62a, 63a, and 64a flows.

[0107]

[0113] The first water discharge pipe 171 and the second water discharge pipe 172 are arranged in parallel and may be connected to common water discharge pipes 612, 622, 632, and 642 that communicate with the indoor heat exchangers 61a, 62a, 63a, and 64a.

[0108]

[0114] The first water discharge pipe 171, the second water discharge pipe 172 and the common water discharge pipes 612, 622, 632, and 642 may be connected by a three-way valve 173, for example.

[0109]

[0115] Therefore, the three-way valve 173 allows the water in the common water discharge pipes 612 , 622 , 632 , and 642 to flow through either the first water discharge pipe 171 or the second water discharge pipe 172 .

[0110]

[0116] The common water discharge pipes 612, 622, 632, and 642 may be connected to the discharge pipes of the indoor heat exchangers 61a, 62a, 63a, and 64a.

[0111]

[0117] The third branch pipe 183 may be connected to first water inflow pipes 165a, 165b, 165c, and 165d through which water flows into the indoor heat exchangers 61a, 62a, 63a, and 64a.

[0112]

[0118] The fourth branch pipe 184 may be connected to a second water inflow pipe 167d through which water flows into each of the indoor heat exchangers 61a, 62a, 63a, and 64a.

[0113]

[0119] The first water inlet pipes 165a, 165b, 165c, and 165d and the second water inlet pipe 167d are arranged in parallel and may be connected to common inlet pipes 611, 621, 631, and 641 that communicate with the indoor heat exchangers 61a, 62a, 63a, and 64a.

[0114]

[0120] A first valve 166 may be provided in each of the first water inlet pipes 165a, 165b, 165c, and 165d, and a second valve 167 may be provided in each of the second water inlet pipes 167d.

[0115]

[0121] FIG. 3 is a cycle diagram showing the flow of refrigerant and water in a heat exchanger during cooling operation of an air conditioner according to an embodiment of the present invention.

[0116]

[0122] 2 and 3, when the air conditioner 1 is in cooling operation (when a large number of indoor units are in cooling operation), high-pressure liquid refrigerant condensed in the outdoor heat exchanger 15 of the outdoor unit 10 flows through the third outdoor unit connecting pipe 27 and then can be distributed to the second refrigerant pipes 121, 122, 123, and 124.

[0117]

[0123] At this time, the expansion valves 125, 126, 127, and 128 provided in the second refrigerant pipes 121, 122, 123, and 124 are opened to a predetermined degree, so that the refrigerant can be reduced in pressure to a low pressure refrigerant while passing through the expansion valves 125, 126, 127, and 128.

[0118]

[0124] The decompressed refrigerant flows along the refrigerant flow passages 140a of the heat exchangers 140, 141, 142, and 143 and can evaporate through heat exchange with water.

[0119]

[0125] While the air conditioner 1 is in cooling operation, the bypass valves 131, 136 are in a closed state.

[0120]

[0126] Therefore, the refrigerant that has been heat exchanged while passing through the refrigerant passage 140a of the second heat exchanger 141 can be prevented from flowing to the second refrigerant pipe 121 of the first heat exchanger 141 through the first bypass pipe 130. In addition, the refrigerant that has been heat exchanged while passing through the refrigerant passage 140a of the fourth heat exchanger 143 can be prevented from flowing to the second refrigerant pipe 123 of the third heat exchanger 142 through the second bypass pipe 135.

[0121]

[0127] The refrigerant flowing through the refrigerant passages 140a of the first and second heat exchangers 140 and 141 may pass through the first and second refrigerant pipes 111a and 111b and then flow into the first common air duct 111. The refrigerant flowing into the first common air duct 111 flows into the second outdoor unit connecting pipe 25 through the third branch pipe 103a.

[0122]

[0128] The refrigerant flowing through the refrigerant flow paths 140a of the third and fourth heat exchangers 142, 143 may pass through the first and second refrigerant pipes 112a, 112b and then flow into the second common air duct 112. The refrigerant flowing into the second common air duct 112 flows into the second outdoor unit connecting pipe 25 through the fourth branch pipe 104a.

[0123]

[0129] While the air conditioner 1 is in cooling operation, the valves 101, 102 of the first branch pipe 101a and the second branch pipe 102a are closed, and the valves 103, 104 of the third branch pipe 103a and the fourth branch pipe 104a are opened.

[0124]

[0130] The refrigerant discharged to the second outdoor unit connecting pipe 25 flows into the outdoor unit 10 and can be sucked into the compressor 11. The high-pressure refrigerant compressed in the compressor 11 is condensed in the outdoor heat exchanger 15, and the condensed liquid refrigerant can flow along the third outdoor unit connecting pipe 27 again.

[0125]

[0131] In summary, during cooling operation of the air conditioner 1, the heat exchangers 140, 141, 142, and 143 function as "evaporators" that evaporate the refrigerant in an abnormal low-pressure state.

[0126]

[0132] Since the heat exchangers 140, 141, 142, and 143 are connected in parallel, the length of the evaporating refrigerant path is short and the number of refrigerant paths can be increased, thereby preventing a drop in evaporation pressure and improving the performance of the refrigerant cycle.

[0127]

[0133] Meanwhile, the water flowing through the water flow path 140b of each of the heat exchangers 140, 141, 142, and 143 is cooled by heat exchange with the refrigerant, and the cooled water is supplied to each of the indoor heat exchangers 61a, 62a, 63a, and 64a to perform cooling.

[0128]

[0134] In this embodiment, the water discharged to the first common discharge pipe 162 may flow to the first indoor heat exchanger 61a and the second indoor heat exchanger 62a. Conversely, the water discharged to the second common discharge pipe 164 may flow to the third indoor heat exchanger 63a and the second indoor heat exchanger 64a.

[0129]

[0135] For example, the water discharged to the first common discharge pipe 162 may flow to the first indoor heat exchanger 61a and the second indoor heat exchanger 62a through the first water inlet pipes 165a and 165b.

[0130]

[0136] On the other hand, the water discharged to the second common discharge pipe 164 may flow to the third indoor heat exchanger 63a and the fourth indoor heat exchanger 64a through the second water inlet pipe 167d.

[0131]

[0137] The water flowing through each of the indoor heat exchangers 61a, 62a, 63a, and 64a can exchange heat with indoor air sent to the indoor heat exchangers.

[0132]

[0138] The water that has exchanged heat with the refrigerant in each of the heat exchangers 140, 141, 142, and 143 is in a low temperature state, so when the water exchanges heat with the indoor air while flowing through the indoor heat exchangers 61a, 62a, 63a, and 64a, the indoor air is cooled, thereby enabling the room to be cooled.

[0133]

[0139] In this embodiment, the water that has flowed through the first and second indoor heat exchangers 61a and 62a can flow to the first common inflow pipe 161 side.

[0134]

[0140] For example, the water flowing through the first and second indoor heat exchangers 61 a and 62 a may flow along the first water discharge pipe 171 and then flow into the first common inlet pipe 161 .

[0135]

[0141] On the other hand, the water that has flowed through the third and fourth indoor heat exchangers 63a and 64a can flow to the second common inflow pipe 163 side.

[0136]

[0142] For example, the water flowing through the third and fourth indoor heat exchangers 63 a and 64 a may flow along the second water discharge pipe 172 and then flow into the second common inlet pipe 163 .

[0137]

[0143] FIG. 4 is a cycle diagram showing the flow of refrigerant and water in a heat exchanger during heating operation of an air conditioner according to an embodiment of the present invention.

[0138]

[0144] 2 and 4, when the air conditioner 1 is in heating operation (when multiple indoor units are in heating operation), high-pressure gas-phase refrigerant compressed in the compressor 11 of the outdoor unit 10 flows through the first outdoor unit connecting pipe 20 and then branches into the first branch pipe 101a and the second branch pipe 101b.

[0139]

[0145] During heating operation of the air conditioner 1, the valves 101, 102 of the first and second branch pipes 101a, 101b are opened, and the valves 103, 104 of the third and fourth branch pipes 103a, 104a are closed.

[0140]

[0146] The refrigerant branched to the first branch pipe 101 a flows along the first common air duct 111 and then flows into the first refrigerant pipe 111 a of the first heat exchanger 140 .

[0141]

[0147] In addition, the refrigerant branched to the second branch pipe 101b flows along the second common air duct 112 and then flows into the first refrigerant pipe 112a of the third heat exchanger 142.

[0142]

[0148] During heating operation of the air conditioner 1, the first expansion valve 125 and the third expansion valve 127 may be closed, and the second expansion valve 126 and the fourth expansion valve 128 may be opened to a predetermined opening degree.

[0143]

[0149] Furthermore, when the air conditioner 1 is in heating operation, the bypass valves 131, 132 can be opened.

[0144]

[0150] Therefore, the refrigerant flowing into the first refrigerant pipe 111 a of the first heat exchanger 140 is discharged to the second refrigerant pipe 121 after exchanging heat with water while passing through the first heat exchanger 140 .

[0145]

[0151] Since the first expansion valve 125 is closed and the first bypass valve 131 is open, the refrigerant discharged to the second refrigerant pipe 121 flows to the first refrigerant pipe 111b of the second heat exchanger 141 via the first bypass pipe 130.

[0146]

[0152] The refrigerant that has flowed into the first refrigerant pipe 111 b of the second heat exchanger 141 is discharged to the second refrigerant pipe 122 after exchanging heat with water while passing through the second heat exchanger 141 .

[0147]

[0153] The refrigerant discharged to the second refrigerant pipe 122 passes through the second expansion valve 126 and then flows into the third outdoor unit connecting pipe 27 .

[0148]

[0154] In addition, the refrigerant that has flowed into the first refrigerant pipe 112 a of the third heat exchanger 142 is discharged to the second refrigerant pipe 123 after exchanging heat with water while passing through the third heat exchanger 142 .

[0149]

[0155] Since the third expansion valve 127 is closed and the second bypass valve 136 is open, the refrigerant discharged to the second refrigerant pipe 123 flows to the first refrigerant pipe 112b of the fourth heat exchanger 143 via the second bypass pipe 135.

[0150]

[0156] The refrigerant that has flowed into the first refrigerant pipe 112b of the fourth heat exchanger 143 is heat exchanged with water while passing through the fourth heat exchanger 143, and then is discharged into the second refrigerant pipe .

[0151]

[0157] The refrigerant discharged to the second refrigerant pipe 124 passes through the fourth expansion valve 128 and then flows into the third outdoor unit connecting pipe 27.

[0152]

[0158] Meanwhile, the flow of water during heating operation of the air conditioner 1 can be the same as the flow of water during cooling operation, so a detailed description will be omitted.

[0153]

[0159] In summary, during heating operation of the air conditioner 1, the heat exchangers 140, 141, 142, and 143 function as "condensers" that condense high-pressure gas-phase refrigerant.

[0154]

[0160] Since the first and second heat exchangers 140 and 141 are connected in series, the refrigerant can be condensed sequentially while passing through the first heat exchanger 140 and the second heat exchanger 141. Therefore, the condensation heat amount of the refrigerant is increased, thereby improving the condensation performance.

[0155]

[0161] In addition, since the third and fourth heat exchangers 142, 143 are connected in series, the refrigerant can be condensed sequentially while passing through the third heat exchanger 142 and the fourth heat exchanger 143. Therefore, the condensation heat amount of the refrigerant is increased, and the condensation performance can be improved.

[0156]

[0162] FIG. 5 is a cycle diagram showing the flow of refrigerant and water in the case where only some of a large number of heat exchangers are used during heating operation of an air conditioner according to an embodiment of the present invention.

[0157]

[0163] 2 and 5, when the number of indoor units operating in heating mode is small or the heating load of the indoor units is small, only some of the heat exchangers may be used as condensers.

[0158]

[0164] In FIG. 5, the first heat exchanger 140 and the third heat exchanger 142 are shown as being used as condensers.

[0159]

[0165] When the air conditioner 1 is in heating operation, the high-pressure gas-phase refrigerant compressed by the compressor 11 of the outdoor unit 10 flows through the first outdoor unit connecting pipe 20 and then branches into the first branch pipe 101a and the second branch pipe 101b.

[0160]

[0166] During heating operation of the air conditioner 1, the valves 101, 102 of the first and second branch pipes 101a, 101b are opened, and the valves 103, 104 of the third and fourth branch pipes 103a, 104a are closed.

[0161]

[0167] The refrigerant branched to the first branch pipe 101 a flows along the first common air duct 111 and then flows into the first refrigerant pipe 111 a of the first heat exchanger 140 .

[0162]

[0168] In addition, the refrigerant branched to the second branch pipe 101b flows along the second common air duct 112 and then flows into the first refrigerant pipe 112a of the third heat exchanger 142.

[0163]

[0169] When the air conditioning device 1 is in heating operation, if only one of the first and second heat exchangers 140, 141 is used, the first expansion valve 125 is opened, the second expansion valve 126 is closed, and the first bypass valve 131 is closed.

[0164]

[0170] In this embodiment, a check valve 132 is provided at the connection between the first refrigerant pipe 111a of the first heat exchanger 140 and the first refrigerant pipe 111b of the second heat exchanger 141. Therefore, when it is desired to use only some of the heat exchangers during heating operation, only the first heat exchanger 141 of the first and second heat exchangers 140 and 141 can be used.

[0165]

[0171] Furthermore, when the air conditioning device 1 is in heating operation, if only one of the third and fourth heat exchangers 142, 143 is used, the third expansion valve 127 is opened, the fourth expansion valve 128 is closed, and the second bypass valve 136 is closed.

[0166]

[0172] In this embodiment, a check valve 137 is provided at a portion connected between the first refrigerant pipe 112a of the third heat exchanger 142 and the first refrigerant pipe 112b of the fourth heat exchanger 143. Therefore, when it is desired to use only some of the heat exchangers during heating operation, only the third heat exchanger 142 of the third and fourth heat exchangers 142, 143 can be used.

[0167]

[0173] The refrigerant that has flowed through the first heat exchanger 140 and the third heat exchanger 142 flows through the first expansion valve 125 and the third expansion valve 127, and then flows to the outdoor unit 10 via the third outdoor unit connecting pipe 27.

[0168]

[0174] Meanwhile, during cooling operation of the air conditioner, it is also possible to use only a portion of the multiple heat exchangers.

[0169]

[0175] In this case, the expansion valve corresponding to the heat exchanger to be used is opened, and the expansion valve corresponding to the remaining unused heat exchanger is closed. Regardless of which heat exchanger is used, the bypass valves 131 and 136 can be kept closed.

[0170]

[0176] During cooling operation, for example, even if the first heat exchanger 140 is not used and the second heat exchanger 141 is used, the first check valve 132 allows the flow of refrigerant in the first refrigerant piping of the second heat exchanger, so that the refrigerant that has flowed through the second heat exchanger 141 can flow into the first common air pipe 111.

[0171]

[0177] FIG. 6 is a cycle diagram showing the flow of refrigerant and water in an air conditioner when some of the indoor units according to one embodiment of the present invention are in heating operation and the other parts are in cooling operation.

[0172]

[0178] 2 and 6, in this embodiment, some of the indoor units may operate in heating mode and the other may operate in cooling mode. In this case, some of the heat exchangers may function as evaporators and the other may function as condensers.

[0173]

[0179] In the following, an example will be described in which the first to third indoor units 61, 62, 63 are in heating operation and the fourth indoor unit 64 is in cooling operation.

[0174]

[0180] Since the first to third indoor units 61, 62, and 63 are operated in heating mode and the fourth indoor unit 64 is operated in cooling mode, for example, the first and second heat exchangers 140 and 141 can function as condensers and the third and fourth heat exchangers 142 and 143 can function as evaporators.

[0175]

[0181] A high-pressure gas-phase refrigerant compressed by the compressor 11 of the outdoor unit 10 flows through the first outdoor-unit connecting pipe 20 and then branches into the first branch pipe 101a.

[0176]

[0182] In order for the first and second heat exchangers 140 and 141 to function as condensers, the valve 101 of the first branch pipe 101a may be opened and the valve 103 of the third branch pipe 103a may be closed. The first expansion valve 125 may be closed and the second expansion valve 126 may be opened to a predetermined degree. The first bypass valve 131 may be opened.

[0177]

[0183] Then, the refrigerant in the first branch pipe 101 a flows along the first common air duct 111 and then flows into the first refrigerant pipe 111 a of the first heat exchanger 140 .

[0178]

[0184] The refrigerant flowing into the first refrigerant pipe 111 a of the first heat exchanger 140 exchanges heat with water while passing through the first heat exchanger 140 , and then is discharged into the second refrigerant pipe 121 .

[0179]

[0185] The refrigerant discharged to the second refrigerant pipe 121 flows into the first refrigerant pipe 111 b of the second heat exchanger 141 through the first bypass pipe 130 .

[0180]

[0186] The refrigerant that has flowed into the first refrigerant pipe 111 b of the second heat exchanger 141 is discharged to the second refrigerant pipe 122 after exchanging heat with water while passing through the second heat exchanger 141 .

[0181]

[0187] The refrigerant discharged to the second refrigerant pipe 122 passes through the second expansion valve 126 and is then combined with the liquid refrigerant that has flowed into the third outdoor unit connecting pipe 27 .

[0182]

[0188] On the other hand, the high-pressure liquid refrigerant condensed in the outdoor heat exchanger 15 of the outdoor unit 10 may flow through the third outdoor unit connecting pipe 27 and then be distributed to the second refrigerant pipes 123 and 124 .

[0183]

[0189] In order for the third and fourth heat exchangers 142, 143 to function as evaporators, the third expansion valve 127 and the fourth expansion valve 128 are opened to a predetermined opening degree, and the second bypass valve 136 is closed.

[0184]

[0190] Therefore, the refrigerant can be decompressed to a low pressure refrigerant while passing through the third and fourth expansion valves 127 and 128.

[0185]

[0191] The decompressed refrigerant flows along the refrigerant flow paths of the third and fourth heat exchangers 142 and 143 and can evaporate through heat exchange with water.

[0186]

[0192] The refrigerant flowing through the refrigerant passages of the third and fourth heat exchangers 142 and 143 may pass through the first and second refrigerant pipes 112a and 112b and then flow to the second common air duct 112. The refrigerant flowing to the second common air duct 112 flows to the second outdoor unit connecting pipe 25 through the fourth branch pipe 104a.

[0187]

[0193] The refrigerant discharged to the second outdoor unit connecting pipe 25 flows into the outdoor unit 10 and may be sucked into the compressor 11. The high-pressure refrigerant compressed in the compressor 11 is condensed in the outdoor heat exchanger 15, and the condensed liquid refrigerant may flow along the third outdoor unit connecting pipe 27 again.

[0188]

[0194] Meanwhile, the water flowing through the water flow paths of the first and second heat exchangers 140, 141 is heated by heat exchange with the refrigerant, and the water flowing through the water flow paths of the third and fourth heat exchangers 142, 143 is cooled by heat exchange with the refrigerant.

[0189]

[0195] Since the first to third indoor units 61, 62, and 63 are in heating operation, the water discharged to the first common discharge pipe 162 can flow to the first to third indoor heat exchangers 61a, 62a, and 63a.

[0190]

[0196] On the other hand, since the fourth indoor unit 64 is in cooling operation, the water discharged to the second common discharge pipe 164 may flow to the fourth indoor heat exchanger 64a.

[0191]

[0197] For example, the water discharged to the first common discharge pipe 162 may flow to the first indoor heat exchanger, the second indoor heat exchanger, and the third indoor heat exchanger through the first water inlet pipes 165a, 165b, and 165c.

[0192]

[0198] On the other hand, the water discharged to the second common discharge pipe 164 may flow into the fourth indoor heat exchanger 64a through the second water inlet pipe 167d.

[0193]

[0199] The water flowing through each of the indoor heat exchangers 61a, 62a, 63a, and 64a can exchange heat with indoor air sent to the indoor heat exchangers.

[0194]

[0200] The water that has exchanged heat with the refrigerant in the first and second heat exchangers 140, 141 is at a high temperature, so when the water exchanges heat with the indoor air while flowing through the first to third indoor heat exchangers 61a, 62a, 63a, the indoor air is heated, making it possible to heat the room.

[0195]

[0201] On the other hand, since the water that has exchanged heat with the refrigerant in the fourth heat exchanger 143 is in a low temperature state, when the water exchanges heat with the indoor air while flowing through the fourth indoor heat exchanger 64a, the indoor air is cooled, thereby enabling cooling of the room.

[0196]

[0202] In this embodiment, the water that has flowed through the first to third indoor heat exchangers 61a, 62a, and 63a can flow to the first common inflow pipe 161 side.

[0197]

[0203] For example, the water flowing through the first to third indoor heat exchangers 61a, 62a, and 63a may flow along the first water discharge pipe 171 and then flow into the first common inlet pipe 161.

[0198]

[0204] On the other hand, the water that has flowed through the fourth indoor heat exchanger 64a can flow to the second common inflow pipe 163 side.

[0199]

[0205] For example, the water flowing through the fourth indoor heat exchanger 64 a may flow along the second water discharge pipe 172 and then flow into the second common inlet pipe 163 .

[0200]

[0206] In the above embodiment, the heat exchanger is described as including the first to fourth heat exchangers, but it may include at least the first and second heat exchangers. In this case, the second and fourth branch pipes and the valves provided in the branch pipes may be omitted.

[0201]

[0207] In addition, in this embodiment, the pipes and valves for allowing all of the multiple heat exchangers to function as condensers, all to function as evaporators, or some of the multiple heat exchangers to function as condensers and the other parts to function as evaporators, can be collectively referred to as a refrigerant flow path varying means.

[0202]

[0208] For example, the refrigerant flow path varying means can vary the refrigerant flow path so that the refrigerant flows in parallel through the multiple heat exchangers when the indoor unit is in cooling operation, and can vary the refrigerant flow path so that the refrigerant flows sequentially through the multiple heat exchangers when the indoor unit is in heating operation.

[0203]

[0209] In addition, the piping and valves for changing the water flow path so that all of the multiple indoor units are operated in heating mode, all of the multiple indoor units are operated in cooling mode, or some of the multiple indoor units are operated in heating mode and the other some are operated in cooling mode can be collectively referred to as a water flow path changing means.

[0204]

[0210] For example, the water flow path varying means varies the water flow path so that water flows to the heat exchanger acting as a condenser when the indoor unit is in heating operation, and so that water flows to the heat exchanger acting as an evaporator when the indoor unit is in cooling operation.

[0205]

[0211] The above description is merely illustrative of the technical concept of the present invention, and various modifications and variations may be made by those skilled in the art without departing from the essential characteristics of the present invention. More specifically, various modifications and variations of the changes and / or arrangements of the components may be made within the scope of the specification, drawings and appended claims of the present invention. In addition to the various modifications and variations of the changes and / or arrangements of the components, selective uses will be obvious to those skilled in the art.

Claims

1. An outdoor unit in which a refrigerant circulates; An indoor unit that circulates water; a heat exchange device that connects the outdoor unit and the indoor unit and exchanges heat between the refrigerant and water; a first outdoor unit connecting pipe connected to the outdoor unit and through which a high-pressure gas-phase refrigerant flows; a second outdoor unit connecting pipe connected to the outdoor unit and through which a low-pressure gas-phase refrigerant flows; a third outdoor unit connecting pipe connected to the outdoor unit and through which a liquid refrigerant flows; The heat exchange device includes: a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger; a first refrigerant pipe connected to one side of each of the first heat exchanger, the second heat exchanger, the third heat exchanger, and the fourth heat exchanger; a second refrigerant pipe connected to the other side of each of the first heat exchanger, the second heat exchanger, the third heat exchanger, and the fourth heat exchanger; a first branch pipe and a second branch pipe connected to the first outdoor unit connecting pipe; a third branch pipe and a fourth branch pipe connected to the second outdoor unit connecting pipe; a first common air pipe connecting the first branch pipe and the third branch pipe and connected to first refrigerant pipes of the first and second heat exchangers; a second common air pipe connecting the second branch pipe and the fourth branch pipe and connected to first refrigerant pipes of the third and fourth heat exchangers; an expansion valve provided in the second refrigerant pipe; a bypass pipe connecting a second refrigerant pipe of the first heat exchanger and a first refrigerant pipe of the second heat exchanger; a bypass valve provided in the bypass piping, the third outdoor unit connecting pipe is connected to second refrigerant pipes of the first and second heat exchangers.

2. The first heat exchanger includes a refrigerant flow path through which a refrigerant flows, The air-conditioning apparatus according to claim 1 , wherein the bypass pipe is connected to a portion of the second refrigerant pipe of the first heat exchanger between the expansion valve and the refrigerant flow path.

3. The air conditioner according to claim 2 , further comprising a check valve provided in the first refrigerant pipe of the second heat exchanger.

4. The air conditioning apparatus of claim 3, wherein the check valve blocks refrigerant in a first refrigerant piping of a first heat exchanger from flowing to the first refrigerant piping of the second heat exchanger, and allows refrigerant in the first refrigerant piping of the second heat exchanger to flow to the first refrigerant piping of the first heat exchanger.

5. 4. The air conditioning apparatus of claim 3, wherein during cooling operation of the indoor unit, the expansion valve of the second refrigerant piping is opened and the bypass valve is closed so that the refrigerant discharged from the outdoor unit flows through the second refrigerant piping of each of the heat exchangers to each of the heat exchangers and is then discharged into the first refrigerant piping of each of the heat exchangers.

6. The air conditioner according to claim 5 , wherein during cooling operation of the indoor unit, the refrigerant that has passed through the second heat exchanger passes through the check valve.

7. The air conditioning apparatus of claim 3, wherein during cooling operation of the indoor unit, in order to use some of the first and second heat exchangers, the expansion valves corresponding to the heat exchangers to be used are opened, the expansion valves corresponding to the heat exchangers not being used are closed, and the bypass valve is closed.

8. The air conditioner according to claim 4, wherein when the second heat exchanger is used and the first heat exchanger is not used, the refrigerant that has flowed through the second heat exchanger passes through the check valve.

9. 4. The air conditioning apparatus of claim 3, wherein during heating operation of the indoor unit, an expansion valve provided in a second refrigerant piping of the first heat exchanger is closed, an expansion valve provided in a second refrigerant piping of the second heat exchanger is opened, and the bypass valve is opened so that the refrigerant that has flowed through the first heat exchanger flows through the second heat exchanger.

10. 4. The air conditioning apparatus of claim 3, wherein during heating operation of the indoor unit, in order to use some of the first and second heat exchangers, an expansion valve provided in the second refrigerant piping of the first heat exchanger is opened, an expansion valve provided in the second refrigerant piping of the second heat exchanger is closed, and the bypass valve is closed.

11. The air conditioner according to claim 2 , wherein each of the heat exchangers includes a water flow path through which water flows to exchange heat with the refrigerant, and the water that has flowed through the water flow path flows to the indoor unit.

12. The air conditioner of claim 1 , further comprising valves provided in the first and third branch pipes.

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