Outdoor unit and refrigeration cycle device

Abstract

A parallel flow-type heat exchanger (21) comprises a first header (102A), a second header (102B), and a plurality of refrigerant pipes (103). The first header (102A) is provided with a first wall (P1) and a second wall (P2). Refrigerant pipes belonging to a second group (103G2) are disposed further downstream in the refrigerant flow of refrigerant pipes belonging to a first group (103G1). The number of the refrigerant pipes belonging to the second group (103G2) is smaller than the number of the refrigerant pipes belonging to the first group (103G1). An outdoor unit comprises a temperature sensor (98) disposed in a first portion (H1) of the first header (102A).

Description

Outdoor units and refrigeration cycle devices

[0001] The present disclosure relates to an outdoor unit and a refrigeration cycle device.

[0002] In recent years, refrigeration cycle devices equipped with parallel flow condensers (PFCs) that are advantageous for size and weight reduction have become available.

[0003] Japanese Patent Application Laid-Open No. 2015-068622 discloses a refrigeration cycle device equipped with such a PFC.

[0004] Japanese Patent Application Laid-Open No. 2015-068622

[0005] In a refrigeration cycle device equipped with a PFC dedicated to condensation, which has corrugated fins arranged between flat tubes, the refrigerant becomes a supercooled liquid in the latter half of the condensation process, reducing its volume and resulting in a decrease in flow velocity if the parallel flow paths are used as is. For this reason, the number of parallel flow paths of the PFC is reduced in the supercooling section in the latter half of the condensation process, increasing the flow velocity in the latter half and improving heat transfer performance.

[0006] However, when operating conditions such as the outside air temperature change, the amount of refrigerant distributed in the condenser may decrease, making it impossible to ensure supercooling at the inlet of the supercooling section. In this case, gas refrigerant is mixed into part of the supercooling refrigerant section where liquid refrigerant normally flows. In the supercooling section, where the number of parallel flow paths is reduced, the refrigerant becomes a two-phase flow, causing a sudden increase in pressure loss and a drop in saturation temperature. In other words, the refrigerant temperature in the latter half of the PFC drops below the outside air temperature, making heat exchange impossible. Therefore, to maintain the condensation performance of the PFC, it is necessary to avoid two-phase flow in the supercooling section.

[0007] An object of the present invention is to provide an outdoor unit and a refrigeration cycle apparatus that can reliably ensure a degree of subcooling at the outlet of a heat exchanger.

[0008] The present disclosure relates to a condenser for use in a refrigeration cycle apparatus. The condenser is a top-flow type condenser including a fan and a parallel-flow heat exchanger. The heat exchanger includes a first header, a second header, and a plurality of refrigerant pipes connecting the first header and the second header. The first header includes a first wall and a second wall. A first number of refrigerant pipes are connected to a first section of the first header sandwiched between the first wall and the second wall. The second header includes a third wall. The third wall is located at a position that separates the second header into a section of the second header to which a first group of refrigerant pipes of the first number of refrigerant pipes is connected and a section of the second header to which a second group of refrigerant pipes of the first number of refrigerant pipes is connected. The refrigerant pipes belonging to the second group are arranged downstream in the refrigerant flow relative to the refrigerant pipes belonging to the first group. The number of refrigerant pipes belonging to the second group is smaller than the number of refrigerant pipes belonging to the first group. The condenser further includes a temperature sensor arranged in the first section of the first header.

[0009] According to the outdoor unit and refrigeration cycle device of the present disclosure, the degree of subcooling at the outlet of the heat exchanger can be reliably ensured, and therefore the condenser can perform properly even if external conditions, etc., change.

[0010] FIG. 1 is a diagram illustrating the overall configuration of a refrigeration cycle device of the present embodiment. FIG. 2 is a vertical cross-sectional view illustrating the structure of an outdoor unit. FIG. 3 is a horizontal cross-sectional view shown at III-III in FIG. 2. FIG. 4 is a perspective view illustrating the detailed configuration of a heat exchanger 21. FIG. 5 is a simplified diagram illustrating the flow of refrigerant in the heat exchanger 21. FIG. 6 is a flowchart illustrating control when a fan is used. FIG. 7 is a flowchart illustrating control when an expansion valve is used. FIG. 8 is a flowchart illustrating control when both the fan and the expansion valve are adjusted.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. While several embodiments will be described below, it is intended from the beginning of the application that the configurations described in each embodiment may be appropriately combined. Note that identical or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated.

[0012] Fig. 1 is a diagram showing the overall configuration of a refrigeration cycle apparatus according to the present embodiment. The refrigeration cycle apparatus 1 shown in Fig. 1 includes an outdoor unit 2, an indoor unit 3, and extension pipes 82 and 86. In the refrigeration cycle apparatus 1, the outdoor unit 2 is a heat source device, and the indoor unit 3 is a load device.

[0013] The outdoor unit 2 is configured to be connected to the indoor unit 3 by extension pipes 82 and 86. The outdoor unit 2 includes a compressor 10, a parallel-flow heat exchanger 21, a fan 22, and pipes 80, 81, and 87. In the refrigeration cycle apparatus 1, the heat exchanger 21 is a condenser.

[0014] The flow path from the compressor 10 through the heat exchanger 21 to the connection port to the indoor unit 3 is configured to form, together with the indoor unit 3, a circulation flow path through which the refrigerant circulates.

[0015] The indoor unit 3 includes an expansion valve 50, an evaporator 60, a fan 62, and pipes 83, 84, and 85. The expansion valve 50 is, for example, an electronic expansion valve (LEV) whose opening degree is controlled.

[0016] The compressor 10 compresses the refrigerant drawn in from the pipe 87 and discharges it to the pipe 80. The compressor 10 is configured to adjust its operating frequency in accordance with a control signal from the control device 91. By adjusting the operating frequency of the compressor 10, the amount of refrigerant circulating is adjusted, and the refrigeration capacity of the refrigeration cycle device can be adjusted. Various types of compressors 10 can be used, such as a scroll type, a rotary type, a screw type, etc.

[0017] The heat exchanger 21 condenses the refrigerant discharged from the compressor 10 to the pipe 80 and flows it to the pipe 81. The heat exchanger 21 is configured so that the high-temperature, high-pressure gas refrigerant discharged from the compressor 10 exchanges heat with outside air. Through this heat exchange, the refrigerant that has released heat condenses and changes to a liquid phase. The fan 22 supplies outside air to the heat exchanger 21, with which the refrigerant exchanges heat in the heat exchanger 21. The refrigerant pressure on the discharge side of the compressor 10 can be adjusted by adjusting the rotation speed of the fan 22.

[0018] The outdoor unit 2 further includes pressure sensors 96, 97 and a control device 91. The pressure sensor 96 detects the pressure PH of the refrigerant discharged from the compressor 10 and outputs the detected value to the control device 91. The pressure sensor 97 detects the pressure PL of the refrigerant drawn into the compressor 10 and outputs the detected value to the control device 91.

[0019] The control device 91 is configured to include a CPU (Central Processing Unit) 92, a memory 94 (ROM (Read Only Memory) and RAM (Random Access Memory)), etc. The CPU 92 deploys a program stored in the ROM into the RAM, etc., and executes it. The program stored in the ROM is a program in which the processing procedures of the control device 91 are written. The control device 91 controls each device in the refrigeration cycle device 1 in accordance with these programs. This control is not limited to processing by software, but can also be processed by dedicated hardware (electronic circuits).

[0020] The indoor unit 3 is installed in a space to be cooled, such as a living room, a cooling room in a refrigerated warehouse, or a showcase.

[0021] Fig. 2 is a vertical cross-sectional view for explaining the structure of the outdoor unit, and Fig. 3 is a horizontal cross-sectional view taken along line III-III in Fig. 2.

[0022] 2, a heat exchanger 21 and a fan 22 are housed in a housing 23 of the outdoor unit 2. The outdoor unit 2 is a top-flow type including the fan 22 and the heat exchanger 21 of a parallel flow type.

[0023] The fan 22 is disposed at the top of the outdoor unit 2 and is configured to generate an airflow that enters the outdoor unit 2 from the side thereof, passes through the heat exchanger 21, and is discharged from above the outdoor unit 2.

[0024] The fan 22 is a propeller fan with a vertical rotation axis. As shown in FIG. 3 , the heat exchanger 21 includes a plurality of refrigerant pipes 103 connecting the header 102A and the header 102B. Each of the plurality of refrigerant pipes 103 is a flat refrigerant pipe and is arranged so that its flat direction is horizontal. When viewed from above in the vertical direction, each of the plurality of refrigerant pipes 103 of the heat exchanger 21 is bent to surround the lower space of the fan 22. In FIGS. 2 and 3 , the heat exchanger 21 is bent to surround the lower space of the fan 22 on three sides, but it may also surround the lower space on two or four sides. Alternatively, the heat exchanger 21 may be divided so that the lower space is sandwiched between the pipes on two sides.

[0025] Fig. 4 is a perspective view illustrating the detailed configuration of the heat exchanger 21. Fig. 5 is a simplified diagram illustrating the flow of refrigerant in the heat exchanger 21. For ease of explanation, Figs. 4 and 5 show the refrigerant pipe 103, which is bent as in Fig. 3, in a straightened state.

[0026] The heat exchanger 21 includes metal fins 104, a plurality of refrigerant pipes 103, and headers 102A and 102B. The heat exchanger 21 has a PFC type configuration in which a refrigerant flows in parallel through the plurality of refrigerant pipes 103. Specifically, the metal fins 104 are corrugated fins made of aluminum, each refrigerant pipe 103 is a flat pipe as shown in FIG. 4, and the headers 102A and 102B are cylindrical headers. The refrigerant pipes 103 are divided into a plurality of groups 103G1, 103G2, 103G3, and 103G4.

[0027] The header 102A is formed with holes for inserting the refrigerant pipes 103. The headers 102A and 102B are also provided with walls P1, P2, and P3 as partitions for allowing the refrigerant to flow sequentially through groups 103G3, 103G1, 103G2, and 103G4, which are groups of refrigerant pipes 103.

[0028] The first header 102A includes a first wall P1 and a second wall P2. The first wall P1 and the second wall P2 divide the first header 102A into portions H1, H2, and H3. The second header 102B includes a third wall P3. The third wall P3 divides the second header 102B into portions H4 and H5. As shown in FIGS. 4 and 5 , the refrigerant inlet 101 is provided in the portion H2, and the refrigerant outlet 108 is provided in the portion H3.

[0029] A first number of refrigerant tubes (groups 103G1 and 103G2) of the multiple refrigerant tubes are connected to a first portion H1 sandwiched between the first wall P1 and the second wall P2 of the first header 102A. A third wall P3 is provided at a position that separates the second header 102B into a portion H4 of the second header 102B and a portion H5 of the second header 102B. The other ends (upstream) of the refrigerant tubes in the first group 103G1 of the first number of refrigerant tubes are connected to the portion H4 of the second header 102B. The other ends (downstream) of the refrigerant tubes in the second group 103G2 of the first number of refrigerant tubes are connected to the portion H5 of the second header 102B.

[0030] As shown in FIG. 4, each of the plurality of refrigerant pipes 103 is a flat refrigerant pipe, and is arranged so that the flat direction is horizontal.

[0031] In the heat exchanger 21, the first header 102A and the second header 102B are arranged so that their longitudinal directions are aligned vertically, and the plurality of refrigerant pipes 103 are arranged so that their longitudinal directions are aligned horizontally. In the heat exchanger 21, as shown in FIG. 2 , the refrigerant pipes of the first group 103G1 are arranged closer to the fan 22 than the refrigerant pipes of the second group 103G2.

[0032] As shown in FIGS. 4 and 5, the plurality of refrigerant pipes 103 include refrigerant pipes belonging to a third group 103G3 and a fourth group 103G4 in addition to a first group 103G1 and a second group 103G2.

[0033] One end of the refrigerant pipes in the third group 103G3 is connected to the second portion H2 of the first header 102A, which is adjacent to the first portion H1 of the first header 102A with the first wall P1 as the boundary. The other end of the refrigerant pipes in the third group 103G3 is connected to the portion H4 of the second header 102B, which is separated by the third wall P3. The upstream ends of the refrigerant pipes in the first group 103G1 are also connected to the portion H4.

[0034] One end of the refrigerant pipes belonging to the fourth group 103G4 is connected to the third portion H3 adjacent to the first portion H2 of the first header 102A with the second wall P2 as the boundary, and the other end of the refrigerant pipes belonging to the fourth group 103G4 is connected to the portion H5 of the second header 102B separated by the third wall P3 and to which the refrigerant pipes belonging to the second group 103G2 are connected.

[0035] As shown by the arrows in Figure 5, the refrigerant flows through groups 103G3, 103G1, 103G2, and 103G4, which are groups of refrigerant pipes 103. That is, the refrigerant pipes belonging to the first group 103G1 are arranged downstream in the refrigerant flow from the refrigerant pipes belonging to the third group 103G3. The refrigerant pipes belonging to the second group 103G2 are arranged downstream in the refrigerant flow from the refrigerant pipes belonging to the first group 103G1. The refrigerant pipes belonging to the fourth group 103G4 are arranged downstream in the refrigerant flow from the refrigerant pipes belonging to the second group 103G2.

[0036] The number of refrigerant pipes decreases from upstream to downstream. That is, in the example of Figure 5, the number of refrigerant pipes belonging to the first group 103G1 (6 pipes) is fewer than the number of refrigerant pipes belonging to the third group 103G3 (7 pipes). The number of refrigerant pipes belonging to the second group 103G2 (3 pipes) is fewer than the number of refrigerant pipes belonging to the first group 103G1 (6 pipes). The number of refrigerant pipes belonging to the fourth group 103G4 (2 pipes) is fewer than the number of refrigerant pipes belonging to the second group 103G2 (3 pipes). However, the specific numbers do not need to be the same as those in Figure 5.

[0037] The outdoor unit 2 further includes a temperature sensor 98 disposed in the first portion H1 of the first header 102A. By disposing the temperature sensor 98 in this position, it becomes easy to control the refrigeration cycle device so that the area downstream of the temperature sensor installation portion becomes a supercooled state, with the area being the boundary.

[0038] Specifically, the control device 91 detects the degree of supercooling in the portion H1 of the header 102A in the supercooling section of the heat exchanger 21 using the temperature sensor 98, and performs control to ensure the degree of supercooling.

[0039] In order to adjust the degree of subcooling of the portion H1 of the header 102A in the subcooling section to a set value (1K to 2K), the control device 91 controls either the opening degree of the expansion valve (LEV) or the fan rotation speed, or both.

[0040] 6 is a flowchart for explaining control when a fan is used. First, in step S1, the control device 91 obtains the saturation temperature from the pressure value detected by the pressure sensor 96. The saturation temperature is obtained by converting the pressure into the saturation temperature using a map stored in advance in a memory or the like.

[0041] Subsequently, in step S2, the control device 91 subtracts the temperature measured by the temperature sensor 98 from the saturation temperature obtained in step S1 to calculate the degree of supercooling SC.

[0042] Then, in step S3, the control device 91 determines whether the degree of supercooling SC is smaller than a lower limit judgment value (for example, 1 (K)). If the degree of supercooling SC is smaller than the lower limit judgment value (YES in S3), the degree of supercooling is insufficient, so the control device 91 increases the rotation speed of the fan 22 in step S4 and proceeds to step S5. On the other hand, if the degree of supercooling SC is equal to or greater than the lower limit judgment value (NO in S3), the control device 91 skips step S4 and proceeds to step S5.

[0043] In step S5, the control device 91 determines whether the degree of supercooling SC is greater than an upper limit judgment value (for example, 5 (K)). If the degree of supercooling SC is greater than the upper limit judgment value (YES in S5), the degree of supercooling is too high, so the control device 91 reduces the rotation speed of the fan 22 in step S6 and exits the processing of this flowchart. On the other hand, if the degree of supercooling SC is equal to or less than the upper limit judgment value (NO in S5), the control device 91 does not perform the processing of step S6 and exits the processing of this flowchart.

[0044] 7 is a flowchart for explaining control when an expansion valve is used. First, in step S11, the control device 91 refers to a map stored in advance in a memory or the like, and obtains a saturation temperature from the pressure value detected by the pressure sensor 96.

[0045] Subsequently, in step S12, the control device 91 subtracts the temperature measured by the temperature sensor 98 from the saturation temperature obtained in step S11 to calculate the degree of supercooling SC.

[0046] Then, in step S13, the control device 91 determines whether the degree of supercooling SC is smaller than a lower limit judgment value (for example, 1 (K)). If the degree of supercooling SC is smaller than the lower limit judgment value (YES in S13), the degree of supercooling is insufficient, so the control device 91 reduces the opening of the expansion valve 50 in step S14 and proceeds to step S15. On the other hand, if the degree of supercooling SC is equal to or greater than the lower limit judgment value (NO in S13), the control device 91 skips step S14 and proceeds to step S15.

[0047] In step S15, the control device 91 determines whether the degree of supercooling SC is greater than an upper limit judgment value (for example, 5 (K)). If the degree of supercooling SC is greater than the upper limit judgment value (YES in S15), the degree of supercooling is too high, so the control device 91 increases the opening of the expansion valve 50 in step S16 and exits the processing of this flowchart. On the other hand, if the degree of supercooling SC is equal to or less than the upper limit judgment value (NO in S15), the control device 91 does not perform the processing of step S16 and exits the processing of this flowchart.

[0048] It is also possible to control both the fan and the expansion valve. In this case, the fan is controlled first. Prioritizing fan control results in smaller changes in power consumption than controlling the expansion valve.

[0049] FIG. 8 is a flowchart for explaining control when adjusting both the fan and the expansion valve.

[0050] First, in step S21, the control device 91 refers to a map stored in advance in a memory or the like, and acquires the saturation temperature from the pressure value detected by the pressure sensor 96.

[0051] Subsequently, in step S22, the control device 91 subtracts the temperature measured by the temperature sensor 98 from the saturation temperature obtained in step S21 to calculate the degree of supercooling SC.

[0052] Then, in step S23, the control device 91 determines whether the degree of supercooling SC is smaller than a lower limit judgment value (for example, 1 (K)). If the degree of supercooling SC is smaller than the lower limit judgment value (YES in S23), the degree of supercooling is insufficient.

[0053] Here, the fan 22 is controlled with priority, but if the rotation speed f (fan) of the fan 22 is at its upper limit, the fan 22 cannot be increased in speed, so in step S24 the control device 91 determines whether the rotation speed f (fan) is less than the upper limit.

[0054] If the rotation speed f(fan) is less than the upper limit (YES in S24), the control device 91 increases the rotation speed of the fan 22 in step S25 and proceeds to step S27. On the other hand, if the rotation speed f(fan) is equal to or greater than the upper limit (NO in S24), the control device 91 decreases the opening of the expansion valve 50 in step S25 and proceeds to step S27.

[0055] If the degree of subcooling SC is equal to or greater than the lower limit judgment value (NO in S23), the control device 91 proceeds to step S27 without performing steps S24-S26.

[0056] In step S27, the control device 91 determines whether the degree of supercooling SC is greater than an upper limit judgment value (for example, 5 (K)). If the degree of supercooling SC is greater than the upper limit judgment value (YES in S27), the degree of supercooling is too high.

[0057] Here, the fan 22 is controlled with priority, but if the rotation speed f (fan) of the fan 22 is at the lower limit, the fan 22 cannot be decelerated. Therefore, in step S28, the control device 91 determines whether the rotation speed f (fan) is greater than the lower limit.

[0058] If the rotation speed f(fan) is greater than the lower limit (YES in S28), the control device 91 reduces the rotation speed of the fan 22 in step S29 and exits the processing of this flowchart. On the other hand, if the rotation speed f(fan) is equal to or less than the lower limit (NO in S28), the control device 91 increases the opening of the expansion valve 50 in step S30 and exits the processing of this flowchart.

[0059] If the degree of supercooling SC is equal to or greater than the lower limit judgment value (NO in S27), the control device 91 does not perform the processes of steps S28-S30 and exits the process of this flowchart.

[0060] In this embodiment, the refrigerant is not particularly specified, but if R32, which has a large latent heat, is used as the refrigerant, the condensation promoting effect is large and it is particularly effective.

[0061] (Summary) The embodiment of the present invention will be summarized below with reference to the drawings again.

[0062] (Item 1) The present disclosure relates to an outdoor unit 2 used in a refrigeration cycle apparatus 1. The outdoor unit 2 is a top-flow type including a fan 22 and a parallel-flow heat exchanger 21. The heat exchanger includes a first header 102A, a second header 102B, and a plurality of refrigerant pipes 103 connecting the first header 102A and the second header 102B. The first header 102A includes a first wall P1 and a second wall P2. A first number of refrigerant pipes (103G1+103G2) of the plurality of refrigerant pipes are connected to a first portion H1 of the first header 102A sandwiched between the first wall P1 and the second wall P2. The second header 102B includes a third wall P3. The third wall P3 is provided at a position that separates the second header 102B into a portion H4 of the second header 102B to which the refrigerant pipes of the first group 103G1 of the first number of refrigerant pipes are connected, and a portion H5 of the second header 102B to which the refrigerant pipes of the second group 103G2 of the first number of refrigerant pipes are connected. The refrigerant pipes belonging to the second group 103G2 are arranged downstream in the refrigerant flow relative to the refrigerant pipes belonging to the first group 103G1. The number of refrigerant pipes belonging to the second group 103G2 is smaller than the number of refrigerant pipes belonging to the first group 103G1. The outdoor unit 2 further includes a temperature sensor 98 arranged in the first portion H1 of the first header 102A.

[0063] (Clause 2) In the outdoor unit described in clause 1, as shown in Figures 2, 4 and 5, the fan 22 is disposed at the top of the outdoor unit 2 and is configured to generate an airflow that enters the outdoor unit 2 from the side thereof, passes through the heat exchanger 21, and is discharged from above the outdoor unit 2. The heat exchanger 21 is disposed so that the first header 102A and the second header 102B are positioned along the vertical direction and the multiple refrigerant pipes 103 are positioned along the horizontal direction, and as shown in Figure 2, the refrigerant pipes of the first group 103G1 are positioned closer to the fan 22 than the refrigerant pipes of the second group 103G2.

[0064] (Item 3) In the outdoor unit described in item 2, as shown in Fig. 4, each of the plurality of refrigerant pipes 103 is a flat refrigerant pipe and is arranged so that its flatness is horizontal. The fan 22 is a propeller fan with a vertical rotation axis. As shown in Fig. 3, each of the plurality of refrigerant pipes 103 is bent so as to surround the space below the fan 22 when viewed vertically from above.

[0065] (Item 4) In the outdoor unit described in item 1, as shown in Figures 4 and 5, the multiple refrigerant pipes 103 include refrigerant pipes belonging to a third group 103G3 and a fourth group 103G4 in addition to the first group 103G1 and the second group 103G2. One end of the refrigerant pipes belonging to the third group 103G3 is connected to the second portion H2 of the first header 102A, which is adjacent to the first portion H1 with the first wall P1 as the boundary. The other end of the refrigerant pipes belonging to the third group 103G3 is connected to the portion H4 of the second header 102B, which is separated by the third wall P3 and to which the refrigerant pipes belonging to the first group 103G1 are connected. One end of the refrigerant pipes belonging to the fourth group 103G4 is connected to the third portion H3 of the first header 102A, which is adjacent to the first portion H2 with the second wall P2 as the boundary. The other ends of the refrigerant pipes belonging to the fourth group 103G4 are connected to a portion H5 of the second header 102B separated by the third wall P3, to which the refrigerant pipes belonging to the second group 103G2 are connected.

[0066] (Section 5) In another aspect, the present disclosure relates to a refrigeration cycle apparatus 1. The refrigeration cycle apparatus 1 includes the outdoor unit 2 described in Section 1, an indoor unit 3 including an evaporator, a compressor 10 and an expansion valve 50 mounted in the outdoor unit 2 or the indoor unit 3, and a control device 91 configured to perform control to ensure the degree of subcooling of the refrigerant pipes belonging to the second group 103G2 in accordance with the output of a temperature sensor 98.

[0067] (Item 6) In the refrigeration cycle device 1 described in item 5, as shown in Figures 6 to 8, the control device 91 is configured to control either or both of the fan 22 and the expansion valve 50 based on the output of the temperature sensor 98 so as to ensure the degree of subcooling of the refrigerant pipes belonging to the second group 103G2.

[0068] (Item 7) In the refrigeration cycle device 1 described in item 6, as shown in FIG. 8, when controlling both the fan 22 and the expansion valve 50, the control device 91 is configured to prioritize the fan 22 over the expansion valve 50 and control it based on the output of the temperature sensor 98 if the rotation speed of the fan 22 is less than the upper limit speed.

[0069] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0070] 1 Refrigeration cycle device, 2 Outdoor unit, 3 Indoor unit, 10 Compressor, 21 Heat exchanger, 22, 62 Fan, 23 Housing, 50 Expansion valve, 60 Evaporator, 80-87 Piping, 91 Control device, 94 Memory, 96, 97 Pressure sensor, 98 Temperature sensor, 101 Refrigerant inlet, 102A, 102B Header, 103 Refrigerant pipe, 103G1-103G4 Group, 104 Metal fin, 108 Refrigerant outlet, P1-P3 Wall.

Claims

1. An outdoor unit used in a refrigeration cycle device, the outdoor unit being a top flow type including a fan and a parallel flow type heat exchanger, the heat exchanger comprising: a first header; a second header; and a plurality of refrigerant pipes connecting the first header and the second header, the first header comprising a first wall and a second wall, a first number of refrigerant pipes among the plurality of refrigerant pipes being connected to a first portion of the first header sandwiched between the first wall and the second wall, the second header comprising a third wall, the third wall being provided at a position dividing the second header into a portion of the second header to which a first group of refrigerant pipes among the first number of refrigerant pipes are connected and a portion of the second header to which a second group of refrigerant pipes among the first number of refrigerant pipes are connected, the refrigerant pipes belonging to the second group being arranged downstream in the refrigerant flow from the refrigerant pipes belonging to the first group, and the number of refrigerant pipes belonging to the second group being less than the number of refrigerant pipes belonging to the first group, the outdoor unit comprising: The outdoor unit further includes a temperature sensor disposed in the first portion of the first header.

2. The outdoor unit according to claim 1, wherein the fan is arranged above the outdoor unit and is configured to generate an airflow that enters the outdoor unit from the side thereof, passes through the heat exchanger, and is discharged from the top of the outdoor unit; and the heat exchanger is arranged so that the first header and the second header are positioned vertically, the plurality of refrigerant pipes are positioned horizontally, and the first group of refrigerant pipes are positioned closer to the fan than the second group of refrigerant pipes.

3. An outdoor unit as described in claim 2, wherein each of the plurality of refrigerant pipes is a flat refrigerant pipe and is arranged so that its flat direction is horizontal, the fan is a propeller fan with a vertical rotation axis, and each of the plurality of refrigerant pipes is bent so as to surround the lower space of the fan when viewed from above in the vertical direction.

4. The outdoor unit described in claim 1, wherein the plurality of refrigerant pipes include, in addition to the first group and the second group, refrigerant pipes belonging to a third group and refrigerant pipes belonging to a fourth group, one end of the refrigerant pipe belonging to the third group is connected to a second portion of the first header adjacent to the first portion with the first wall as a boundary, the other end of the refrigerant pipe belonging to the third group is connected to a portion of the second header separated by the third wall to which the refrigerant pipes belonging to the first group are connected, one end of the refrigerant pipe belonging to the fourth group is connected to a third portion of the first header adjacent to the first portion with the second wall as a boundary, and the other end of the refrigerant pipe belonging to the fourth group is connected to a portion of the second header separated by the third wall to which the refrigerant pipes belonging to the second group are connected.

5. A refrigeration cycle device comprising: an outdoor unit according to claim 1; an indoor unit equipped with an evaporator; a compressor and an expansion valve mounted in said outdoor unit or said indoor unit; and a control device configured to perform control to ensure the degree of subcooling of the refrigerant pipes belonging to said second group in accordance with the output of said temperature sensor.

6. The refrigeration cycle device according to claim 5, wherein the control device is configured to control either or both of the fan and the expansion valve based on the output of the temperature sensor so as to ensure the degree of subcooling of the refrigerant pipes belonging to the second group.

7. The refrigeration cycle device according to claim 6, wherein the control device is configured to, when controlling both the fan and the expansion valve, prioritize the fan over the expansion valve and control it based on the output of the temperature sensor if the rotation speed of the fan is below an upper limit speed.

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