Outdoor unit for air conditioner and air conditioner comprising same

Abstract

An outdoor unit for an air conditioner according to the present invention comprises a housing that forms an outer enclosure and a first heat exchanger and a second heat exchanger that are provided in the housing in the right-left direction. The first heat exchanger and the second heat exchanger each comprise a plurality of heat transfer tubes that are arranged at intervals in the right-left direction and extend in the vertical direction, an upper header that is provided above the plurality of heat transfer tubes such that upper ends of the plurality of heat transfer tubes are inserted therein, and a lower header that is provided below the plurality of heat transfer tubes such that lower ends of the plurality of heat transfer tubes are inserted therein.

Description

Outdoor unit for air conditioner and air conditioner equipped with same

[0001] The present disclosure relates to an outdoor unit for an air conditioner and an air conditioner including the same, and more particularly to the configuration of a heat exchanger in the outdoor unit of the air conditioner.

[0002] 2. Description of the Related Art Conventionally, there are air conditioners that are capable of maintaining the heating function of the indoor unit of the air conditioner even during defrosting (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a refrigeration system comprising a main casing, an air intake port at one end of the main casing, an air outlet port at the other end of the main casing, an air passage located between the air intake port and the air outlet port within the main casing, an evaporative heat exchanger located on the air intake side of the air passage, a blower located between the evaporative heat exchanger and the air outlet port, and a compressor that flows refrigerant into a refrigeration circuit including the evaporative heat exchanger. The air conditioner is characterized in that the evaporative heat exchanger is divided into at least two heat exchanger sections based on a refrigerant distribution path, and each section is provided with a bypass circuit that bypasses gas discharged from the compressor and an electromagnetic on-off valve that controls the bypass state of the bypass circuit, so that defrost operation is performed alternately for each of the divided heat exchanger sections without reversing the refrigeration cycle of the refrigeration circuit.

[0004] JP 2009-085484 A

[0005] In Patent Document 1, when the lower heat exchanger, which is an evaporative heat exchanger divided into an upper heat exchanger and a lower heat exchanger, is operating in a frosted state while the upper heat exchanger is defrosting, water melted from the upper heat exchanger flows to the lower heat exchanger and concentrates there, causing frost to form more quickly in the lower heat exchanger and increasing the defrosting capacity required for the lower heat exchanger. As a result, it takes longer to defrost the lower heat exchanger, which increases the time required to complete defrosting, resulting in a problem of reduced heating capacity.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an outdoor unit for an air conditioner that maintains the heating function of the indoor unit of the air conditioner even during defrosting while suppressing a decrease in heating capacity, and an air conditioner equipped with the outdoor unit.

[0007] The outdoor unit of the air conditioner according to the present disclosure comprises a housing that forms an outer shell, and a first heat exchanger and a second heat exchanger that are provided within the housing and arranged in a left-right direction, and the first heat exchanger and the second heat exchanger each comprise a plurality of heat transfer tubes that are arranged at intervals in the left-right direction and extend in a vertical direction, an upper header that is provided above the plurality of heat transfer tubes and into which the upper ends of the plurality of heat transfer tubes are inserted, and a lower header that is provided below the plurality of heat transfer tubes and into which the lower ends of the plurality of heat transfer tubes are inserted.

[0008] An air conditioner according to the present disclosure includes the above-described outdoor unit of the air conditioner and an indoor unit of the air conditioner.

[0009] According to the air conditioner outdoor unit and the air conditioner equipped therewith, the first and second heat exchangers arranged laterally within the housing each include a plurality of heat transfer tubes arranged at intervals in the laterally direction and extending vertically. This ensures that the refrigerant flows uniformly through each heat transfer tube, preventing meltwater from concentrating in any one location and ensuring that the defrosting capacity required for each heat transfer tube is uniform. Furthermore, because the first and second heat exchangers are arranged laterally, meltwater does not concentrate on either side, ensuring that the defrosting capacity required for each heat exchanger is uniform. As a result, the time required to complete defrosting can be reduced, and the heating function of the air conditioner's indoor unit can be maintained even during defrosting while reducing a decrease in heating capacity.

[0010] FIG. 1 is a schematic diagram of an outdoor unit of an air conditioner according to Embodiment 1, as seen from the side. FIG. 2 is a schematic diagram of an outdoor unit of an air conditioner according to Embodiment 1, as seen from the rear side. FIG. 3 is a diagram showing the configuration of an air conditioner including an outdoor unit of an air conditioner according to Embodiment 1. FIG. 4 is a schematic diagram of an outdoor heat exchanger of an outdoor unit of an air conditioner according to Embodiment 1, as seen from the front side. FIG. 5 is a schematic diagram of an outdoor heat exchanger of an outdoor unit of an air conditioner according to Embodiment 2, as seen from the front side. FIG. 6 is a schematic diagram of an outdoor heat exchanger of an outdoor unit of an air conditioner according to Embodiment 3, as seen from the front side. FIG. 7 is a schematic diagram of an outdoor heat exchanger of an outdoor unit of an air conditioner according to Embodiment 4, as seen from the front side. FIG. 8 is a schematic diagram of an outdoor heat exchanger of an outdoor unit of an air conditioner according to Embodiment 5, as seen from the front side. FIG. 9 is a schematic diagram of a heat transfer tube of an outdoor heat exchanger of an outdoor unit of an air conditioner according to Embodiment 6, as seen in plan view.

[0011] Embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. Furthermore, the size relationships between the components in the drawings may differ from those in reality. Furthermore, in the drawings, components with the same reference numerals are identical or equivalent, and this applies throughout the specification. Furthermore, the configurations of the components shown throughout the specification are merely examples and are not limited to these descriptions. Furthermore, for ease of understanding, directional terms (e.g., "up," "down," "right," "left," "front," "rear," etc.) are used as appropriate. However, these notations are used solely for the convenience of explanation and do not limit the arrangement or orientation of the device or parts. In the specification, the positional relationships between the components, the extension directions of the components, and the arrangement directions of the components generally refer to the heat exchanger when installed and ready for use.

[0012] Embodiment 1. Fig. 1 is a schematic diagram of an outdoor unit 10 of an air conditioner according to Embodiment 1, as viewed from the side. Fig. 2 is a schematic diagram of the outdoor unit 10 of an air conditioner according to Embodiment 1, as viewed from the rear. As shown in Figs. 1 and 2 , the outdoor unit 10 of the air conditioner according to Embodiment 1 (hereinafter also simply referred to as the outdoor unit 10) includes a substantially rectangular parallelepiped housing 19 that forms an outer shell. A blower chamber 19a and a machine chamber 19b are formed inside the housing 19. The blower chamber 19a houses an outdoor blower 15 and an outdoor heat exchanger 30, while the machine chamber 19b houses a compressor 11, a flow path switching device 12, throttle devices 14 (14a, 14b), flow control devices 16 (16a, 16b), and bypass flow control devices 17 (17a, 17b), which will be described later. When the outdoor unit 10 is viewed from the front or rear, the outdoor heat exchanger 30 is made up of a first heat exchanger 30a and a second heat exchanger 30b arranged in the left-right direction.

[0013] FIG. 3 is a diagram showing the configuration of an air conditioner 100 including an outdoor unit 10 of the air conditioner according to the first embodiment. As shown in FIG. 3 , the air conditioner 100 includes an outdoor unit 10 and an indoor unit 20 (hereinafter simply referred to as the indoor unit 20). The outdoor unit 10 includes a compressor 11, a flow switching device 12, an outdoor heat exchanger 30 (first heat exchanger 30a, second heat exchanger 30b), an accumulator 13, a throttling device 14 (14a, 14b), an outdoor blower 15, flow control devices 16 (16a, 16b), and a bypass circuit 2 (2a, 2b). The indoor unit 20 includes an indoor heat exchanger 21 and an indoor blower 22. While the first embodiment illustrates an air conditioner 100 including one outdoor unit 10 and one indoor unit 20, the air conditioner 100 may include two or more outdoor units 10 and two or more indoor units 20. Furthermore, in embodiment 1, an outdoor unit 10 is exemplified in which one outdoor heat exchanger 30 is arranged within the housing 19, i.e., one first heat exchanger 30a and one second heat exchanger 30b are arranged, but the outdoor unit 10 may also be one in which multiple outdoor heat exchangers 30 are arranged within the housing 19, i.e., multiple first heat exchangers 30a and multiple second heat exchangers 30b are arranged.

[0014] The compressor 11, flow switching device 12, indoor heat exchanger 21, throttling devices 14 (14a, 14b), outdoor heat exchanger 30 (first heat exchanger 30a, second heat exchanger 30b), flow control devices 16 (16a, 16b), and accumulator 13 are connected by a main pipe 41 and branch pipes 42 (42a, 42b) to form a main circuit 1 through which the refrigerant circulates. In the main circuit 1, the flow control device 16a, the first heat exchanger 30a, and the throttling device 14a are connected in series by the branch pipe 42a, and the flow control device 16b, the second heat exchanger 30b, and the throttling device 14b are connected in series by the branch pipe 42b, and these are connected in parallel with each other. The refrigerant circuit of the air conditioner 100 is composed of this main circuit 1 and bypass circuits 2 (2a, 2b), which will be described later.

[0015] The compressor 11 draws in a low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges a high-temperature, high-pressure refrigerant. The compressor 11 is, for example, an inverter compressor whose capacity, which is the amount of refrigeration per unit time, is controlled by changing the operating frequency.

[0016] The flow path switching device 12 is, for example, a four-way valve that switches the direction of the refrigerant flow to switch between cooling operation and heating operation. Note that the flow path switching device 12 may be a combination of a two-way valve and a three-way valve instead of a four-way valve.

[0017] The outdoor heat exchanger 30 is composed of a first heat exchanger 30a and a second heat exchanger 30b that operate independently of each other. The first heat exchanger 30a and the second heat exchanger 30b exchange heat between the refrigerant and, for example, outdoor air, and act as a condenser during cooling operation and as an evaporator during heating operation.

[0018] The outdoor blower 15 is provided near the outdoor heat exchanger 30 and sends outdoor air to the outdoor heat exchanger 30 .

[0019] The expansion devices 14 (14a, 14b) reduce the pressure of the refrigerant to expand it. The expansion devices 14 (14a, 14b) are, for example, electronic expansion valves that can adjust the aperture of the aperture, and by adjusting the aperture, the pressure of the refrigerant flowing into the indoor heat exchanger 21 is controlled during cooling operation, and the pressure of the refrigerant flowing into the outdoor heat exchanger 30 is controlled during heating operation.

[0020] The accumulator 13 is provided on the intake side of the compressor 11 and serves to store excess refrigerant that occurs due to differences in operating conditions between cooling and heating, or excess refrigerant that occurs due to transient changes in operation.

[0021] The flow rate control device 16a is provided in the branch pipe 42a and adjusts the amount of refrigerant flowing through the branch pipe 42a. The flow rate control device 16b is provided in the branch pipe 42b and adjusts the amount of refrigerant flowing through the branch pipe 42b. The flow rate control devices 16 (16a, 16b) may be any device that can at least open and close a flow path, and may be, for example, a solenoid valve or a two-way valve.

[0022] The bypass circuit 2 (2a, 2b) includes a bypass pipe 43 (43a, 43b) and a bypass flow control device 17 (17a, 17b). The bypass circuit 2a is a circuit that allows a portion of the refrigerant discharged from the compressor 11 to flow from the main pipe 41 between the compressor 11 and the flow switching device 12 to a branch pipe 42a between the first heat exchanger 30a and the flow control device 16a. The bypass circuit 2b is a circuit that allows a portion of the refrigerant discharged from the compressor 11 to flow from the main pipe 41 between the compressor 11 and the flow switching device 12 to a branch pipe 42b between the second heat exchanger 30b and the flow control device 16b.

[0023] The bypass pipe 43a is a pipe that bypasses the main pipe 41 between the compressor 11 and the flow path switching device 12 to the branch pipe 42a between the first heat exchanger 30a and the flow control device 16a. The bypass pipe 43b is a pipe that bypasses the main pipe 41 between the compressor 11 and the flow path switching device 12 to the branch pipe 42b between the second heat exchanger 30b and the flow control device 16b.

[0024] The bypass flow rate control device 17a is provided in the bypass pipe 43a and controls the amount of refrigerant flowing through the bypass pipe 43a. The bypass flow rate control device 17b is provided in the bypass pipe 43b and controls the amount of refrigerant flowing through the bypass pipe 43b. The bypass flow rate control devices 17 (17a, 17b) may be any device that can at least open and close a flow path, and may be, for example, a solenoid valve or a two-way valve.

[0025] The indoor heat exchanger 21 exchanges heat between the indoor air in the space to be air-conditioned and the refrigerant, for example, and acts as an evaporator during cooling operation and as a condenser during heating operation.

[0026] The indoor blower 22 is provided near the indoor heat exchanger 21 and sends indoor air to the indoor heat exchanger 21 .

[0027] Here, examples of the refrigerant that can be used to circulate through the refrigerant circuit include fluorocarbon refrigerants, HFO refrigerants, etc. Examples of fluorocarbon refrigerants include HFC refrigerants such as R32 refrigerant, R125, and R134a. Examples of mixed refrigerants of HFC refrigerants include R410A, R407c, and R404A. Examples of HFO refrigerants include HFO-1234yf, HFO-1234ze(E), and HFO-1234ze(Z). Other refrigerants include CO ２ The refrigerant may be a mixture of the above refrigerants, such as a refrigerant, an HC refrigerant, an ammonia refrigerant, or a mixture of R32 and HFO-1234yf, or a refrigerant used in a vapor compression heat pump circuit. Examples of the HC refrigerant include propane and isobutane.

[0028] The air conditioner 100 has three operating modes: a cooling operation mode, a normal heating operation mode, and a heating / defrosting operation mode. The cooling operation mode is a mode in which the indoor unit 20 performs cooling operation, with the outdoor heat exchanger 30 functioning as a condenser and the indoor unit 20 cooling the room. The normal heating operation mode is a mode in which the indoor unit 20 performs heating operation, with the outdoor heat exchanger 30 functioning as an evaporator and the indoor unit 20 heating the room. The heating / defrosting operation mode is a mode in which the indoor unit 20 performs heating operation, with a portion of the outdoor heat exchanger 30 being the defrosting target; that is, one of the first heat exchanger 30a and the second heat exchanger 30b is the defrosting target and the other functions as an evaporator and the indoor unit 20 heating the room. In this way, the heating defrost operation mode is an operation mode in which heating operation is maintained while defrosting by having one of the first heat exchanger 30a and the second heat exchanger 30b act as an evaporator while the other is defrosting.

[0029] In the heating / defrosting operation mode, the first heat exchanger 30a and the second heat exchanger 30b are alternately defrosted. For example, in the heating / defrosting operation mode, one of the first heat exchanger 30a and the second heat exchanger 30b functions as an evaporator to perform heating operation while the other heat exchanger is defrosted. Then, in the heating / defrosting operation mode, when defrosting of the other heat exchanger is completed, the other heat exchanger functions as an evaporator to perform heating operation while defrosting of the other heat exchanger is performed. The heating / defrosting operation mode is performed when frost forms on the first heat exchanger 30a and the second heat exchanger 30b during normal heating operation. The heating / defrosting mode may also be switched to when the drive frequency of the compressor 11 becomes lower than a frequency threshold.

[0030] The control device 50 controls the cooling operation and heating operation of the indoor unit 20, changes to the set room temperature, the throttling device 14, the flow rate control device 16, and the bypass flow rate control device 17. The control device 50 according to the first embodiment is configured with, for example, a microcomputer having a control arithmetic processing device such as a CPU (Central Processing Unit). The control device 50 also has a storage device (not shown) that stores data in the form of a program that contains processing procedures related to control, etc. The control arithmetic processing device then executes processing based on the program data to achieve control.

[0031] <Cooling Operation Mode> Next, the flow of refrigerant in the air conditioner 100 in cooling operation mode will be described. In cooling operation mode, the flow path switching device 12 is switched as shown by the dashed lines in Fig. 3, so that the discharge side of the compressor 11 is connected to the first heat exchanger 30a and the second heat exchanger 30b, and the suction side of the compressor 11 is connected to the indoor heat exchanger 21. In addition, the flow control devices 16a and 16b are open, and the bypass flow control devices 17a and 17b are closed.

[0032] The compressor 11 compresses the refrigerant it draws in and discharges the refrigerant in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 passes through the flow switching device 12, branches, and then passes through the flow control devices 16a and 16b, respectively, before flowing into the first heat exchanger 30a and the second heat exchanger 30b, which function as condensers. In the first heat exchanger 30a and the second heat exchanger 30b, the refrigerant exchanges heat with outdoor air sent by the outdoor blower 15, condenses, and liquefies, becoming a medium-temperature, high-pressure liquid refrigerant. The condensed medium-temperature, high-pressure liquid refrigerant flows into the throttling devices 14a and 14b, respectively. The medium-temperature, high-pressure liquid refrigerant that flows into the throttling devices 14a and 14b expands and decompresses in the throttling devices 14a and 14b, becoming a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The gas-liquid two-phase refrigerant merges and flows into the indoor heat exchanger 21, which functions as an evaporator. In the indoor heat exchanger 21, the refrigerant exchanges heat with the indoor air sent by the indoor blower 22, evaporating and gasifying. At this time, the indoor air is cooled, and the room is cooled. The evaporated low-temperature, low-pressure gas refrigerant passes through the flow switching device 12 and the accumulator 13 and is drawn into the compressor 11.

[0033] <Normal heating operation mode> Next, the flow of refrigerant in the air conditioner 100 in heating operation mode will be described. In heating operation mode, the flow path switching device 12 is switched as shown by the solid line in Fig. 3, the discharge side of the compressor 11 is connected to the indoor heat exchanger 21, and the suction side of the compressor 11 is connected to the first heat exchanger 30a and the second heat exchanger 30b. In addition, the flow rate control devices 16a and 16b are open, and the bypass flow rate control devices 17a and 17b are closed.

[0034] The compressor 11 compresses the refrigerant it draws in and discharges it in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 11 passes through the flow switching device 12 and flows into the indoor heat exchanger 21, which functions as a condenser. In the indoor heat exchanger 21, the refrigerant exchanges heat with indoor air sent by the indoor blower 22, condensing and liquefying it, becoming a medium-temperature, high-pressure liquid refrigerant. This warms the indoor air, providing heating within the room. The condensed medium-temperature, high-pressure liquid refrigerant branches and flows into the throttling devices 14a and 14b, respectively. The medium-temperature, high-pressure refrigerant that flows into the throttling devices 14a and 14b expands and decompresses, becoming a medium-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the first heat exchanger 30a and the second heat exchanger 30b, which function as evaporators, respectively. The refrigerant evaporates and gasifies in the first heat exchanger 30a and the second heat exchanger 30b through heat exchange with the outdoor air sent by the outdoor blower 15. The evaporated refrigerant in a low-temperature, low-pressure gas state passes through the flow control devices 16a and 16b, respectively, and merges therewith. Then, the refrigerant passes through the flow switching device 12 and the accumulator 13 and is drawn into the compressor 11.

[0035] <Heating / Defrosting Operation Mode> Next, the refrigerant flow in the air conditioner 100 during heating / defrosting operation mode will be described. During heating / defrosting operation, the flow path switching device 12 is switched as shown by the solid lines in FIG. 3 , connecting the discharge side of the compressor 11 to the indoor heat exchanger 21 and the suction side of the compressor 11 to the first heat exchanger 30a and the second heat exchanger 30b. In the heating / defrosting operation mode, one of the first heat exchanger 30a and the second heat exchanger 30b is selected as the defrosting target and defrosts, while the other acts as an evaporator to continue heating operation. The open / closed states of the flow control devices 16a and 16b, and the bypass flow control devices 17a and 17b are alternately switched, so that the defrosting target alternates between the first heat exchanger 30a and the second heat exchanger 30b. The flow of the refrigerant is switched by switching between the first heat exchanger 30a or the second heat exchanger 30b to be defrosted and the first heat exchanger 30a or the second heat exchanger 30b acting as an evaporator.

[0036] First, a case will be described in which the first heat exchanger 30a is selected as the defrosting target, and the second heat exchanger 30b continues heating by functioning as an evaporator. In this case, the flow control device 16b and the bypass flow control device 17a are open, and the flow control device 16a and the bypass flow control device 17b are closed.

[0037] First, the flow of refrigerant related to heating will be described. The compressor 11 compresses the refrigerant it draws in and discharges the refrigerant in a high-temperature, high-pressure gas state. A portion of the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 passes through the flow switching device 12 and flows into the indoor heat exchanger 21, which functions as a condenser. In the indoor heat exchanger 21, the refrigerant exchanges heat with indoor air sent by the indoor blower 22, condenses, and liquefies, becoming a medium-temperature, high-pressure liquid refrigerant. The condensed medium-temperature, high-pressure liquid refrigerant flows into the expansion device 14b. The medium-temperature, high-pressure refrigerant that flows into the expansion device 14b expands and is reduced in pressure, becoming a medium-pressure, gas-liquid two-phase refrigerant. The refrigerant in the gas-liquid two-phase state does not flow into the first heat exchanger 30a, which is the defrosting target, but flows into the second heat exchanger 30b, which functions as an evaporator, where it evaporates and gasifies through heat exchange with outdoor air sent by the outdoor blower 15. The evaporated refrigerant in a low-temperature, low-pressure gas state passes through the flow control device 16b, the flow path switching device 12, and the accumulator 13, and is drawn into the compressor 11.

[0038] Next, the flow of refrigerant during defrosting will be described. A portion of the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 11 flows into the bypass pipe 43a without passing through the flow switching device 12. The refrigerant flowing into the bypass pipe 43a passes through the bypass flow control device 17a and flows into the first heat exchanger 30a, which is the defrosting target. The refrigerant flowing into the first heat exchanger 30a is cooled by heat exchange with frost adhering to the first heat exchanger 30a. In this way, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 11 flows into the first heat exchanger 30a, melting the frost adhering to the first heat exchanger 30a. After defrosting the first heat exchanger 30a, the refrigerant flowing out of the first heat exchanger 30a passes through the expansion device 14a and merges with the medium-temperature, high-pressure liquid refrigerant condensed in the indoor heat exchanger 21.

[0039] Next, a case will be described in which the second heat exchanger 30b is selected as the defrost target, and the first heat exchanger 30a continues heating by functioning as an evaporator. In this case, the flow control device 16a and the bypass flow control device 17b are open, and the flow control device 16b and the bypass flow control device 17a are closed.

[0040] First, the flow of refrigerant related to heating will be described. The compressor 11 compresses the refrigerant it draws in and discharges the refrigerant in a high-temperature, high-pressure gas state. A portion of the high-temperature, high-pressure gas refrigerant discharged from the compressor 11 passes through the flow switching device 12 and flows into the indoor heat exchanger 21, which functions as a condenser. In the indoor heat exchanger 21, the refrigerant exchanges heat with indoor air sent by the indoor blower 22, condenses, and liquefies, becoming a medium-temperature, high-pressure liquid refrigerant. The condensed medium-temperature, high-pressure liquid refrigerant flows into the expansion device 14a. The medium-temperature, high-pressure refrigerant that flows into the expansion device 14a expands and reduces its pressure, becoming a medium-pressure, gas-liquid two-phase refrigerant. The refrigerant in the gas-liquid two-phase state does not flow to the second heat exchanger 30b, which is the defrosting target, but flows into the first heat exchanger 30a, which functions as an evaporator, where it evaporates and gasifies through heat exchange with outdoor air sent by the outdoor blower 15. The evaporated refrigerant in a low-temperature, low-pressure gas state passes through the flow control device 16a, the flow path switching device 12, and the accumulator 13, and is drawn into the compressor 11.

[0041] Next, the flow of refrigerant during defrosting will be described. A portion of the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 11 flows into the bypass pipe 43b without passing through the flow switching device 12. The refrigerant flowing into the bypass pipe 43b passes through the bypass flow control device 17b and flows into the second heat exchanger 30b, which is the defrosting target. The refrigerant flowing into the second heat exchanger 30b is cooled by heat exchange with frost adhering to the second heat exchanger 30b. In this way, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 11 flows into the second heat exchanger 30b, melting the frost adhering to the second heat exchanger 30b. After defrosting the second heat exchanger 30b, the refrigerant flowing out of the second heat exchanger 30b passes through the expansion device 14b and merges with the medium-temperature, high-pressure liquid refrigerant condensed in the indoor heat exchanger 21.

[0042] Fig. 4 is a schematic diagram of the outdoor heat exchanger 30 of the outdoor unit 10 of the air conditioner according to embodiment 1, as viewed from the front side. As shown in Fig. 4, the first heat exchanger 30a and the second heat exchanger 30b are arranged at intervals in the left-right direction (horizontal direction). The first heat exchanger 30a and the second heat exchanger 30b are fin-tube type heat exchangers, each of which includes a plurality of heat transfer tubes 33 arranged at intervals in the left-right direction (horizontal direction) and extending in the up-down direction (vertical direction), plate-shaped fins 34 provided between adjacent heat transfer tubes 33 and extending in the up-down direction (vertical direction), an upper header 31 provided above the plurality of heat transfer tubes 33 and into which the upper ends of the plurality of heat transfer tubes 33 are inserted, and a lower header 32 provided below the plurality of heat transfer tubes 33 and into which the lower ends of the plurality of heat transfer tubes 33 are inserted.

[0043] The heat transfer tubes 33 are arranged in parallel in the left-right direction (horizontal direction) at intervals so that the air generated by the outdoor blower 15 can flow through them. A refrigerant flows vertically through the tubes extending in the up-down direction (vertical direction). The heat transfer tubes 33 are, for example, flattened tubes having an oval cross section whose width is greater than its length in a cross section perpendicular to the refrigerant flow direction. Fins 34 are connected between adjacent heat transfer tubes 33 and transfer heat to the heat transfer tubes 33. The fins 34 improve the heat exchange efficiency between the air and the refrigerant and may be, for example, corrugated fins, but are not limited thereto. Since heat exchange between the air and the refrigerant occurs on the surfaces of the heat transfer tubes 33, the fins 34 may not be provided. The upper header 31 and the lower header 32 are cylindrical bodies extending in the left-right direction (horizontal direction) and closed at both left and right ends, forming a space within which the refrigerant flows.

[0044] Here, when the heat transfer tubes 33 extend in the left-right direction (horizontal direction), melt water flows from the upper heat transfer tubes 33 and concentrates on the lower heat transfer tubes 33, so the lower heat transfer tubes 33 require a higher defrosting capacity. Furthermore, the lower heat transfer tubes 33 have a low head, making it difficult for the refrigerant to flow, resulting in a small amount of refrigerant flowing through them. On the other hand, melt water does not concentrate on the upper heat transfer tubes 33, so the upper heat transfer tubes 33 require a lower defrosting capacity than the lower heat transfer tubes 33, and the head is high, resulting in a large amount of refrigerant flowing through them. Therefore, the lower heat transfer tubes 33 take longer to defrost than the upper ones, resulting in a longer time required to complete defrosting. Alternatively, when two heat exchangers are arranged one above the other, melt water flows from the upper heat exchanger and concentrates on the lower heat exchanger, resulting in a higher defrosting capacity required for the lower heat exchanger. Therefore, the lower heat exchanger takes longer to defrost than the upper one, resulting in a longer time required to complete defrosting. However, in the first embodiment, because the heat transfer tubes 33 extend in the up-down direction (vertical direction), the refrigerant flows uniformly through each heat transfer tube 33, preventing meltwater from concentrating in any one location. This ensures that the defrosting capacity required for each heat transfer tube 33 is uniform. Furthermore, because the first heat exchanger 30a and the second heat exchanger 30b are arranged in the left-right direction, meltwater does not concentrate on either one. This ensures that the defrosting capacity required for each heat exchanger is uniform, thereby preventing an increase in the time required to complete defrosting. Furthermore, because meltwater generated when melting frost on the surface of one of the first heat exchanger 30a and the second heat exchanger 30b does not flow into the other heat exchanger acting as an evaporator, evaporation operation is not hindered, preventing a decrease in heat exchanger performance and a decrease in heating capacity.

[0045] As described above, the outdoor unit 10 of the air conditioner according to embodiment 1 comprises a housing 19 that forms the outer shell, and a first heat exchanger 30a and a second heat exchanger 30b that are provided within the housing 19 and arranged in the left-right direction. The first heat exchanger 30a and the second heat exchanger 30b are each arranged at intervals in the left-right direction and include a plurality of heat transfer tubes 33 that extend in the up-down direction, an upper header 31 that is provided above the plurality of heat transfer tubes 33 and into which the upper ends of the plurality of heat transfer tubes 33 are inserted, and a lower header 32 that is provided below the plurality of heat transfer tubes 33 and into which the lower ends of the plurality of heat transfer tubes 33 are inserted.

[0046] In the outdoor unit 10 of the air conditioner according to the first embodiment, the first heat exchanger 30a and the second heat exchanger 30b are arranged laterally within the housing 19, and each of them includes a plurality of heat transfer tubes 33 arranged at intervals in the laterally extending direction and extending vertically. This allows the refrigerant to flow uniformly through each heat transfer tube 33, preventing meltwater from concentrating in any one location and ensuring that the defrosting capacity required for each heat transfer tube 33 is uniform. Furthermore, because the first heat exchanger 30a and the second heat exchanger 30b are arranged laterally, meltwater does not concentrate on either one of them, ensuring that the defrosting capacity required for each heat exchanger is uniform. As a result, the time required to complete defrosting can be prevented from becoming longer, and the heating function of the indoor unit 20 of the air conditioner can be maintained even during defrosting while preventing a decrease in heating capacity.

[0047] The air conditioner 100 according to the first embodiment includes the above-described air conditioner outdoor unit 10 and air conditioner indoor unit 20.

[0048] According to the air conditioner 100 of the first embodiment, it is possible to obtain the same effects as those of the outdoor unit 10 of the air conditioner described above.

[0049] Second Embodiment A second embodiment will be described below, but explanations of parts that overlap with those of the first embodiment will be omitted, and parts that are the same as or equivalent to those of the first embodiment will be given the same reference numerals.

[0050] 5 is a schematic diagram of the outdoor heat exchanger 30 of the outdoor unit 10 of the air conditioner according to Embodiment 2, viewed from the front. As shown in FIG. 5, the first heat exchanger 30a and the second heat exchanger 30b are arranged in the left-right direction (horizontal direction), but their headers are in thermal contact with each other. That is, the end of the upper header 31 of the first heat exchanger 30a facing the second heat exchanger 30b is in thermal contact with the end of the upper header 31 of the second heat exchanger 30b facing the first heat exchanger 30a, and the end of the lower header 32 of the first heat exchanger 30a facing the second heat exchanger 30b is in thermal contact with the end of the lower header 32 of the second heat exchanger 30b facing the first heat exchanger 30a.

[0051] The upper header 31 of the first heat exchanger 30a and the upper header 31 of the second heat exchanger 30b are integrally formed, and a partition plate 35 made of a heat conductive material such as metal is provided between them. Similarly, the lower header 32 of the first heat exchanger 30a and the lower header 32 of the second heat exchanger 30b are integrally formed, and a partition plate 35 made of a heat conductive material such as metal is provided between them. However, this is not limited thereto, and the end of the upper header 31 of the first heat exchanger 30a facing the second heat exchanger 30b may be joined to the end of the upper header 31 of the second heat exchanger 30b facing the first heat exchanger 30a, and the end of the lower header 32 of the first heat exchanger 30a facing the second heat exchanger 30b may be joined to the end of the lower header 32 of the second heat exchanger 30b facing the first heat exchanger 30a.

[0052] In this way, by bringing the headers of the first heat exchanger 30a and the second heat exchanger 30b into thermal contact with each other, heat exchange occurs between the high-temperature refrigerant that flows through one of the first heat exchanger 30a and the second heat exchanger 30b when defrosting and the refrigerant that flows through the other heat exchanger that acts as an evaporator.This makes it easier for the refrigerant that flows through the heat exchanger that acts as an evaporator and is then sucked into the compressor 11 to gasify, thereby preventing failure of the compressor 11 due to liquid backflow.

[0053] As described above, in the outdoor unit 10 of the air conditioner according to embodiment 2, the upper header 31 of the first heat exchanger 30a and the upper header 31 of the second heat exchanger 30b are in thermal contact, and the lower header 32 of the first heat exchanger 30a and the lower header 32 of the second heat exchanger 30b are in thermal contact.

[0054] According to the outdoor unit 10 of the air conditioner of embodiment 2, by bringing the headers of the first heat exchanger 30a and the second heat exchanger 30b into thermal contact with each other, heat exchange is carried out between the high-temperature refrigerant that flows when defrosting one of the first heat exchanger 30a and the second heat exchanger 30b and the refrigerant that flows through the other heat exchanger that acts as an evaporator.As a result, the refrigerant that is drawn into the compressor 11 after flowing through the heat exchanger that acts as an evaporator is more likely to gasify, thereby preventing failure of the compressor 11 due to liquid backflow.

[0055] Third Embodiment Hereinafter, a third embodiment will be described, but explanations of parts that overlap with those of the first and second embodiments will be omitted, and parts that are the same as or equivalent to those of the first and second embodiments will be denoted by the same reference numerals.

[0056] Fig. 6 is a schematic diagram of the outdoor heat exchanger 30 of the outdoor unit 10 of the air conditioner according to Embodiment 3, viewed from the front side. As shown in Fig. 6, the first heat exchanger 30a and the second heat exchanger 30b each include a first inlet / outlet pipe 36 and a second inlet / outlet pipe 37. The first inlet / outlet pipe 36 is provided in the upper header 31, and the second inlet / outlet pipe 37 is provided in the lower header 32. Hereinafter, the first inlet / outlet pipe 36 of the first heat exchanger 30a will also be referred to as the first piping, and the first inlet / outlet pipe 36 of the second heat exchanger 30b will also be referred to as the second piping.

[0057] The first inlet / outlet pipe 36 of the first heat exchanger 30a serves as a refrigerant inlet when the first heat exchanger 30a functions as a condenser and as a refrigerant outlet when the first heat exchanger 30a functions as an evaporator. The first inlet / outlet pipe 36 of the second heat exchanger 30b serves as a refrigerant inlet when the second heat exchanger 30b functions as a condenser and as a refrigerant outlet when the second heat exchanger 30b functions as an evaporator. The second inlet / outlet pipe 37 of the first heat exchanger 30a serves as a refrigerant outlet when the first heat exchanger 30a functions as a condenser and as a refrigerant inlet when the first heat exchanger 30a functions as an evaporator. The second inlet / outlet pipe 37 of the second heat exchanger 30b serves as a refrigerant outlet when the second heat exchanger 30b functions as a condenser and as a refrigerant inlet when the second heat exchanger 30b functions as an evaporator.

[0058] The first inlet / outlet pipe 36 of the first heat exchanger 30a is positioned closer to the second heat exchanger 30b than the left-right center of the upper header 31 (dashed line X1 in Figure 6), and the first inlet / outlet pipe 36 of the second heat exchanger 30b is positioned closer to the first heat exchanger 30a than the left-right center of the upper header 31 (dashed line X2 in Figure 6).

[0059] In this way, by positioning the first inlet / outlet pipe 36 of the first heat exchanger 30a closer to the second heat exchanger 30b than the left-right center of the upper header 31, and by positioning the first inlet / outlet pipe 36 of the second heat exchanger 30b closer to the first heat exchanger 30a than the left-right center of the upper header 31, heat exchange occurs between the high-temperature refrigerant that flows when defrosting one of the first heat exchangers 30a and the second heat exchanger 30b and the refrigerant that flows through the other heat exchanger that functions as an evaporator.This makes it easier for the refrigerant that is sucked into the compressor 11 after flowing through the heat exchanger that functions as an evaporator to gasify, thereby preventing failure of the compressor 11 due to liquid backflow.

[0060] As described above, in the outdoor unit 10 of the air conditioner according to embodiment 3, the upper header 31 of the first heat exchanger 30a is provided with a first pipe which serves as an inlet for the refrigerant when the first heat exchanger 30a functions as a condenser, and the upper header 31 of the second heat exchanger 30b is provided with a second pipe which serves as an outlet for the refrigerant when the second heat exchanger 30b functions as an evaporator, with the first pipe being positioned closer to the second heat exchanger 30b than the left-right center of the upper header 31, and the second pipe being positioned closer to the first heat exchanger 30a than the left-right center of the upper header 31.

[0061] According to the outdoor unit 10 of the air conditioner of embodiment 3, the first pipe is arranged closer to the second heat exchanger 30b than the left-right center of the upper header 31 of the first heat exchanger 30a, and the second pipe is arranged closer to the first heat exchanger 30a than the left-right center of the upper header 31 of the second heat exchanger 30b. This allows heat exchange between the high-temperature refrigerant that flows when defrosting one of the first heat exchangers 30a and the second heat exchanger 30b and the refrigerant that flows through the other heat exchanger that acts as an evaporator, so that the refrigerant that is drawn into the compressor 11 after flowing through the heat exchanger that acts as an evaporator is more likely to gasify, thereby preventing failure of the compressor 11 due to liquid backflow.

[0062] Fourth Embodiment A fourth embodiment will be described below, but explanations of parts that overlap with those of the first to third embodiments will be omitted, and parts that are the same as or equivalent to those of the first to third embodiments will be given the same reference numerals.

[0063] Fig. 7 is a schematic diagram of the outdoor heat exchanger 30 of the outdoor unit 10 of the air conditioner according to Embodiment 4, viewed from the front side. As shown in Fig. 7, fins 34 are provided between the heat transfer tube 33 of the first heat exchanger 30a that is arranged closest to the second heat exchanger 30b and the heat transfer tube 33 of the second heat exchanger 30b that is arranged closest to the first heat exchanger 30a (see the Y arrow in Fig. 7), so that the heat transfer tube 33 of the first heat exchanger 30a and the heat transfer tube 33 of the second heat exchanger 30b are in thermal contact with each other.

[0064] In this way, the heat transfer tubes 33 of the first heat exchanger 30a and the heat transfer tubes 33 of the second heat exchanger 30b are in thermal contact via the fins 34, so that when all of the outdoor heat exchangers 30 (i.e., both the first heat exchanger 30a and the second heat exchanger 30b) are used as evaporators or condensers, the heat transfer area of ​​the fins 34 increases, thereby improving heat exchanger performance.

[0065] As described above, the outdoor unit 10 of the air conditioner according to embodiment 4 has fins 34 provided between the heat transfer tube 33 arranged closest to the second heat exchanger 30b of the first heat exchanger 30a and the heat transfer tube 33 arranged closest to the first heat exchanger 30a of the second heat exchanger 30b.

[0066] According to the outdoor unit 10 of the air conditioner of embodiment 4, the heat transfer tubes 33 of the first heat exchanger 30a and the heat transfer tubes 33 of the second heat exchanger 30b are in thermal contact via the fins 34. Therefore, when all of the outdoor heat exchangers 30 (i.e., both the first heat exchanger 30a and the second heat exchanger 30b) are used as evaporators or condensers, the heat transfer area of ​​the fins 34 increases, thereby improving heat exchanger performance.

[0067] Fifth Embodiment Hereinafter, a fifth embodiment will be described, but explanations of parts that overlap with those of the first to fourth embodiments will be omitted, and parts that are the same as or equivalent to those of the first to fourth embodiments will be given the same reference numerals.

[0068] Fig. 8 is a schematic diagram of the outdoor heat exchanger 30 of the outdoor unit 10 of the air conditioner according to Embodiment 5, viewed from the front side. As shown in Fig. 8, no fins 34 are provided between the heat transfer tube 33 of the first heat exchanger 30a that is arranged closest to the second heat exchanger 30b and the heat transfer tube 33 of the second heat exchanger 30b that is arranged closest to the first heat exchanger 30a (see the portion indicated by the arrow Z in Fig. 8), and the heat transfer tube 33 of the first heat exchanger 30a and the heat transfer tube 33 of the second heat exchanger 30b are thermally insulated from each other.

[0069] In this way, by thermally insulating the heat transfer tubes 33 of the first heat exchanger 30a and the heat transfer tubes 33 of the second heat exchanger 30b, heat exchange is no longer performed between the high-temperature refrigerant that flows when defrosting one of the first heat exchanger 30a and the second heat exchanger 30b and the refrigerant that flows through the other heat exchanger that acts as an evaporator.As a result, the heat used to defrost the refrigerant flowing through one heat exchanger is not transferred via the fins 34 to the refrigerant flowing through the other heat exchanger, thereby suppressing a decrease in defrosting performance.

[0070] As described above, the outdoor unit 10 of the air conditioner according to embodiment 5 does not have fins 34 between the heat transfer tube 33 located closest to the second heat exchanger 30b of the first heat exchanger 30a and the heat transfer tube 33 located closest to the first heat exchanger 30a of the second heat exchanger 30b.

[0071] According to the outdoor unit 10 of the air conditioner of embodiment 5, the heat transfer tubes 33 of the first heat exchanger 30a and the heat transfer tubes 33 of the second heat exchanger 30b are thermally insulated from each other, so that there is no heat exchange between the high-temperature refrigerant that flows when defrosting one of the first heat exchanger 30a and the second heat exchanger 30b and the refrigerant that flows through the other heat exchanger that acts as an evaporator. As a result, the heat used to defrost the refrigerant flowing through one heat exchanger is not transferred via the fins 34 to the refrigerant flowing through the other heat exchanger, thereby suppressing a decrease in defrosting performance.

[0072] Sixth Embodiment A sixth embodiment will be described below, but explanations of parts that overlap with those of the first to fifth embodiments will be omitted, and parts that are the same as or equivalent to those of the first to fifth embodiments will be given the same reference numerals.

[0073] Fig. 9 is a schematic plan view of a heat transfer tube 33 of an outdoor heat exchanger 30 of an outdoor unit 10 of an air conditioner according to Embodiment 6. As shown in Fig. 9, each heat transfer tube 33 of the outdoor heat exchanger 30 is a flattened multi-hole tube having a flat shape in which the horizontal width is greater than the vertical width in a cross section perpendicular to the flow direction of the refrigerant, and having a plurality of refrigerant flow paths 33a formed at predetermined intervals along the longitudinal direction within the heat transfer tube 33, through which the refrigerant flows.

[0074] In the heating / defrosting operation mode, liquid refrigerant accumulates in the first heat exchanger 30a or the second heat exchanger 30b that is to be defrosted, and the amount of liquid refrigerant in the indoor heat exchanger 21 decreases by the amount corresponding to the increase in liquid refrigerant present in the outdoor heat exchanger 30. If the heat transfer tubes of the outdoor heat exchanger 30 and the indoor heat exchanger 21 are both circular pipes, the indoor heat exchanger 21 will experience a refrigerant shortage during heating, resulting in a decrease in heating capacity. Therefore, by configuring the heat transfer tube 33 of the outdoor heat exchanger 30 as a flattened multi-hole pipe with a smaller flow path cross-sectional area than a circular pipe, even if the heat transfer tube of the indoor heat exchanger 21 is circular, an increase in the amount of liquid refrigerant present in the outdoor heat exchanger 30 will not significantly affect the amount of refrigerant required by the indoor heat exchanger 21, thereby suppressing a decrease in heating capacity.

[0075] As described above, in the outdoor unit 10 of the air conditioner according to embodiment 5, the first heat exchanger 30a and the second heat exchanger 30b are each a flat multi-hole tube in which the heat transfer tube 33 forms a plurality of refrigerant flow paths 33a arranged along the longitudinal direction.

[0076] According to the outdoor unit 10 of the air conditioner of embodiment 6, the heat transfer tubes 33 of the outdoor heat exchanger 30 are made of flat multi-hole tubes. Therefore, if the heat transfer tubes of the indoor heat exchanger 21 are made of circular tubes, even if the amount of liquid refrigerant present in the outdoor heat exchanger 30 increases, it does not have a significant effect on the amount of refrigerant required by the indoor heat exchanger 21, and therefore a decrease in heating capacity can be suppressed.

[0077] 1 Main circuit, 2 Bypass circuit, 2a Bypass circuit, 2b Bypass circuit, 10 Outdoor unit, 11 Compressor, 12 Flow path switching device, 13 Accumulator, 14 Throttle device, 14a Throttle device, 14b Throttle device, 15 Outdoor blower, 16 Flow rate adjustment device, 16a Flow rate adjustment device, 16b Flow rate adjustment device, 17 Bypass flow rate adjustment device, 17a Bypass flow rate adjustment device, 17b Bypass flow rate adjustment device, 19 Housing, 19a Blower room, 19b Machine room, 20 Indoor unit, 21 Indoor heat exchanger, 22 Indoor blower, 30 Outdoor heat exchanger, 30a First heat exchanger, 30b Second heat exchanger, 31 Upper header, 32 Lower header, 33 Heat transfer tube, 33a Refrigerant flow path, 34 Fin, 35 Partition plate, 36 First inlet / outlet pipe, 37 Second inlet / outlet pipe, 41 main pipe, 42 branch pipe, 42a branch pipe, 42b branch pipe, 43 bypass pipe, 43a bypass pipe, 43b bypass pipe, 50 control device, 100 air conditioner.

Claims

1. A housing that forms an outer shell; a first heat exchanger and a second heat exchanger provided in the housing and arranged in the left-right direction, The first heat exchanger and the second heat exchanger each include: a plurality of heat transfer tubes arranged at intervals in the left-right direction and extending in the up-down direction; an upper header provided above the plurality of heat transfer tubes and into which upper ends of the plurality of heat transfer tubes are inserted; a lower header provided at a lower portion of the plurality of heat transfer tubes and into which lower ends of the plurality of heat transfer tubes are inserted, the upper header of the first heat exchanger and the upper header of the second heat exchanger are in thermal contact with each other, the lower header of the first heat exchanger and the lower header of the second heat exchanger are in thermal contact with each other, a first pipe that serves as an inlet for a refrigerant when the first heat exchanger functions as a condenser is provided in the upper header of the first heat exchanger; a second pipe that serves as an outlet for the refrigerant when the second heat exchanger functions as an evaporator is provided in the upper header of the second heat exchanger; the first pipe is disposed closer to the second heat exchanger than the left-right center of the upper header, The second pipe is disposed closer to the first heat exchanger than the left-right center of the upper header. Air conditioner outdoor unit.

2. The first heat exchanger and the second heat exchanger each include: Fins are provided between adjacent heat transfer tubes. The outdoor unit of an air conditioner according to claim 1.

3. A fin is provided between the heat transfer tube arranged in the first heat exchanger closest to the second heat exchanger and the heat transfer tube arranged in the second heat exchanger closest to the first heat exchanger. The outdoor unit of an air conditioner according to claim 2.

4. No fins are provided between the heat transfer tube of the first heat exchanger that is closest to the second heat exchanger and the heat transfer tube of the second heat exchanger that is closest to the first heat exchanger. The outdoor unit of an air conditioner according to claim 2.

5. The first heat exchanger and the second heat exchanger each include: The heat transfer tube is a flat multi-hole tube that forms a plurality of refrigerant flow paths arranged along the longitudinal direction. The outdoor unit of an air conditioner according to any one of claims 1 to 4.

6. An outdoor unit of an air conditioner according to any one of claims 1 to 4; an indoor unit of an air conditioner; Air conditioner.