WO2023281731A1

WO2023281731A1 - Heat exchanger and air conditioner

Info

Publication number: WO2023281731A1
Application number: PCT/JP2021/025912
Authority: WO
Inventors: 皓亮宮脇; 和久岩▲崎▼; 侑哉森下; 康平名島
Original assignee: 三菱電機株式会社
Priority date: 2021-07-09
Filing date: 2021-07-09
Publication date: 2023-01-12
Also published as: JPWO2023281731A1; JP7566155B2

Abstract

This heat exchanger includes: a first heat exchanger having a first intermediate header extending in the direction of gravity, a first heat transfer tube connected to the first intermediate header and performing heat exchange between a refrigerant and air, and a first partition partitioning the inside of the first intermediate header into a first space and a second space disposed below the first space; and a second heat exchanger provided side-by-side with and upwind of the first heat exchanger and having a second intermediate header extending in the direction of gravity, a second heat transfer tube connected to the second intermediate header and performing heat exchange between a refrigerant and air, and a second partition partitioning the inside of the second intermediate header into a third space and a fourth space disposed below the third space. The first heat transfer tube is provided in a plurality, and the plurality of first heat transfer tubes include a first heat transfer tube connecting to the first space, and a first heat transfer tube connecting to the second space. The first intermediate header constituting the first space is provided with a first outflow port from which the refrigerant flows out, and the first intermediate header constituting the second space is provided with a second outflow port from which the refrigerant flows out. The second intermediate header connects to the first intermediate header and includes a first inflow port through which the refrigerant flows into the third space from the first outflow port, and a second inflow port through which the refrigerant flows into the third space from the second outflow port.

Description

heat exchangers and air conditioners

The present disclosure relates to a heat exchanger having a first heat exchanger and a second heat exchanger and an air conditioner having such a heat exchanger.

An air conditioner is equipped with a heat exchanger that functions as a condenser as one of the components of the refrigeration cycle circuit. The condenser heat-exchanges the incoming gaseous refrigerant with the outside air. The refrigerant that has undergone heat exchange flows out of the condenser as a liquid refrigerant through a gas-liquid two-phase state. At this time, a heat transfer tube group is provided on the windward side and the leeward side as a condenser, and one end of the heat transfer tube group is folded back, and the refrigerant in the gas-liquid two-phase state on the leeward side is flowed to the windward side for heat exchange. There are ways to improve device performance. As a conventional folding means, there is a method of merging the refrigerant at the header of the heat transfer tube outlet on the leeward side and supplying the refrigerant to the header of the heat transfer tube inlet on the windward side (see, for example, Patent Document 1).

JP 2019-132537 A

In the conventional refrigerant circuit configuration, the heat exchanger, which is the condenser, generates a lot of liquid phase in the upper heat transfer tube when the wind speed distribution is formed while it is mounted in the top-blown housing. However, if the heat transfer tube outlets are in communication with each other in the header, the liquid refrigerant that has fallen from the upper heat transfer tube in the header cannot be lifted by only the refrigerant in the lowermost heat transfer tube in the gravity direction, and the liquid refrigerant stays, especially in the middle. Performance degrades under load.

The present disclosure has been made in view of the above circumstances, and aims to provide a heat exchanger and an air conditioner having a first heat exchanger and a second heat exchanger capable of improving heat exchange performance.

A heat exchanger according to the present disclosure includes a first intermediate header extending in the direction of gravity, a first heat transfer tube connected to the first intermediate header and performing heat exchange between refrigerant and air, and the first intermediate header. A first heat exchanger having a first partition that divides the interior into a first space and a second space arranged below the first space; and arranged side by side on the windward side of the first heat exchanger. a second intermediate header extending in the gravitational direction; a second heat transfer tube connected to the second intermediate header for exchanging heat between the refrigerant and the air; A second heat exchanger having a second partition that partitions into three spaces and a fourth space arranged below the third space, wherein the first heat transfer tubes are a plurality, and the plurality of The first heat transfer tube has the first heat transfer tube connected to the first space and the first heat transfer tube connected to the second space, and the first heat transfer tube constituting the first space The intermediate header is provided with a first outlet through which the refrigerant flows out, the first intermediate header forming the second space is provided with a second outlet through which the refrigerant flows out, and the second intermediate header is provided with a second outlet through which the refrigerant flows out. The header is connected to the first intermediate header, and has a first inlet through which the refrigerant flows into the third space through the first outlet, and a second outlet through which the refrigerant flows into the third space. and a second inlet.

According to the present disclosure, the second intermediate header is connected to the first intermediate header, the first inlet through which the liquid-based refrigerant flows into the third space from the first outlet, and the gas-based refrigerant from the second outlet. and a second inlet through which the coolant flows into the third space. As a result, the liquid-based refrigerant and the gas-based refrigerant are mixed in the third space, and it is possible to suppress the liquid refrigerant from falling to the bottom of the second intermediate header. can be improved.

1 is a configuration diagram of an air conditioner according to Embodiment 1. FIG. 1 is a perspective perspective view of an outdoor heat exchanger according to Embodiment 1. FIG. 3 is a vertical cross-sectional view showing the periphery of the first intermediate header and the second intermediate header of the outdoor heat exchanger according to Embodiment 1. FIG. FIG. 4 is a vertical cross-sectional view showing refrigerant flows around a first intermediate header and a second intermediate header of a conventional outdoor heat exchanger. 4 is a longitudinal sectional view showing refrigerant flows around the first intermediate header and the second intermediate header of the outdoor heat exchanger according to Embodiment 1. FIG. It is a conceptual schematic diagram which shows the refrigerant|coolant flow volume which flows into the 1st intermediate header of the conventional outdoor heat exchanger, and wind speed distribution. FIG. 4 is a conceptual schematic diagram showing the flow rate of refrigerant flowing into the first intermediate header and the wind speed distribution of the outdoor heat exchanger according to Embodiment 1; 4 is a performance curve with respect to operating load in the outdoor heat exchanger according to Embodiment 1. FIG. FIG. 2 is a schematic diagram showing an example of a refrigerant channel configuration of the outdoor heat exchanger according to Embodiment 1; FIG. 8 is a vertical cross-sectional view showing a first intermediate header and a second intermediate header of an outdoor heat exchanger according to Embodiment 2; FIG. 11 is a vertical cross-sectional view showing a first intermediate header and a second intermediate header of an outdoor heat exchanger according to Embodiment 3; FIG. 11 is a cross-sectional top view of a first intermediate header and a second intermediate header according to Embodiment 4; 13 is an enlarged cross-sectional view taken along line AA of FIG. 12; FIG. FIG. 13 is an enlarged cross-sectional view taken along the line AA of FIG. 12, showing a first modified example of the first intermediate header and the second intermediate header according to Embodiment 4; 13 is an enlarged cross-sectional view taken along the line AA of FIG. 12, showing a second modification of the first intermediate header and the second intermediate header according to the fourth embodiment; FIG.

An example of a heat exchanger and an air conditioner according to the present disclosure will be described in the following embodiments with reference to the drawings and the like. In addition, in each drawing below, the configurations denoted by the same reference numerals are the same or equivalent configurations. The form of each configuration described in the following embodiments is merely an example. The heat exchanger and air conditioner according to the present disclosure are not limited to each configuration described in the following embodiments. Moreover, the combination of configurations is not limited to the combination in the same embodiment, and the configurations described in different embodiments may be combined. In each of the drawings below, the size relationship of each constituent member may differ from the actual product in which the present disclosure is implemented.

Embodiment 1.
<Configuration>
FIG. 1 is a configuration diagram of an air conditioner 200 according to Embodiment 1. FIG. The white arrows and black arrows along the refrigerant pipe 18 in FIG. 1 indicate the flow direction of the refrigerant during the cooling operation. A white arrow indicates that the refrigerant is in a gaseous state, and a black arrow indicates that the refrigerant is in a liquid state. Further, hatched arrows attached near the first intermediate header 1 and the second intermediate header 2 schematically indicate a gas-liquid two-phase state. The refrigerant flows when the outdoor heat exchanger 10 functions as a condenser. In FIG. 1, the AF direction indicates the direction of air flow, and the direction of the arrow 90 indicates the direction of gravity.

The air conditioner 200 includes a compressor 14 that compresses the refrigerant, an outdoor heat exchanger 10 that functions as a condenser, an expansion device 17 that decompresses and expands the refrigerant, and an indoor heat exchanger 16 that functions as an evaporator. ing. A compressor 14, an outdoor heat exchanger 10, an expansion device 17, and an indoor heat exchanger 16 are sequentially connected by refrigerant pipes 18 to form a refrigeration cycle circuit.

The compressor 14 and the outdoor heat exchanger 10 are housed in the outdoor unit 201. The housing of the outdoor unit 201 is a top-blowing housing provided with a blower 13 that supplies outdoor air to the outdoor heat exchanger 10 and blows the air upward. Also, the indoor heat exchanger 16 and the expansion device 17 are housed in the indoor unit 202 . The indoor unit 202 also accommodates an indoor fan (not shown) that supplies the indoor heat exchanger 16 with indoor air, which is the air in the space to be air-conditioned.

The outdoor heat exchanger 10 has a first heat exchanger 11 and a second heat exchanger 12. The first heat exchanger 11 includes a first intermediate header 1 extending in the direction of gravity 90, and a first heat transfer tube 3_1 (see FIG. 3) connected to the first intermediate header 1 and performing heat exchange between refrigerant and air. have The second heat exchanger 12 is arranged in parallel on the windward side of the first heat exchanger 11 and is connected to the second intermediate header 2 extending in the direction of gravity 90 and the second intermediate header 2 to heat the refrigerant and the air. It has a second heat transfer tube 3_2 to be exchanged.

Next, the detailed configuration of the outdoor heat exchanger 10 will be described.

FIG. 2 is a perspective perspective view of the outdoor heat exchanger 10 according to Embodiment 1. FIG. FIG. 3 is a longitudinal sectional view showing the periphery of the first intermediate header 1 and the second intermediate header 2 of the outdoor heat exchanger 10 according to Embodiment 1. As shown in FIG. This FIG. 3 is a longitudinal sectional view parallel to the extending direction of the first heat transfer tube 3_1 and the second heat transfer tube 3_2.

As shown in FIG. 2, the outdoor heat exchanger 10 is mounted in a top-blowing housing 203 of an outdoor unit 201 having a blower 13 that blows air upward. The top-blowing housing 203 has an air outlet at the top through which the air sent from the blower 13 is discharged. As shown in FIG. 3, the outdoor heat exchanger 10 has a first heat exchanger 11 and a second heat exchanger 12 provided upstream of the first heat exchanger 11 in the air flow direction AF. . The outdoor heat exchanger 10 is composed of at least two rows of first heat exchangers 11 and second heat exchangers 12 .

The first heat exchanger 11 has a plurality of first heat transfer tubes 3_1. The first heat transfer pipes 3_1 extend in the horizontal direction and are arranged at regular intervals in the vertical direction. The second heat exchanger 12 has a plurality of second heat transfer tubes 3_2. The second heat exchangers 12 extend horizontally and are arranged at regular intervals in the vertical direction.

When the outdoor heat exchanger 10 functions as a condenser, the refrigerant flowing through the first heat transfer tube 3_1 and the second heat transfer tube 3_2 is cooled and condensed by the outdoor air. In Embodiment 1, as shown in FIG. 3 , a plurality of fins 4 are connected to a plurality of first heat transfer tubes 3_1 and a plurality of fins 4 are connected to a plurality of second heat transfer tubes 3_2 in order to promote heat exchange between the refrigerant and the outdoor air. A plurality of fins (not shown) are connected.

The first heat exchanger 11 provided downstream of the airflow and the second heat exchanger 12 provided upstream of the airflow are sequentially connected via the first intermediate header 1 and the second intermediate header 2 . The first intermediate header 1 has a structure in which the first heat transfer pipe 3_1 is inserted into a pipe having a constant volume. The second intermediate header 2 is configured such that a second heat transfer tube 3_2 is inserted into a pipe having a constant volume. The first intermediate header 1 is a header that connects at least two of the first heat transfer tubes 3_1 in the same row in the same space. The second intermediate header 2 is a header that connects at least two of the second heat transfer tubes 3_2 in the same row in the same space.

The first intermediate header 1 is partitioned by a first partition 35 into a first space 21 provided on the upper side and a second space 22 provided on the lower side. At least one of the first heat transfer tubes 3_1 connected to the first intermediate header 1 is connected to the first space 21 . At least two first heat transfer tubes 3_1 among the first heat transfer tubes 3_1 connected to the first intermediate header 1 are connected to the second space 22 .

A pipe wall of the first intermediate header 1 that defines the first space 21 is provided with a first outflow port 31_1 through which the refrigerant flows out. A pipe wall of the first intermediate header 1 that defines the second space 22 is provided with a second outlet 32_1 through which the refrigerant flows.

The second intermediate header 2 is partitioned by a second partition 36 into a third space 23 provided on the upper side and a fourth space 24 provided on the lower side. At least one second heat transfer tube 3_2 is connected to the third space 23 . The tube wall of the second intermediate header 2 forming the third space 23 has a first inlet 33_1 and a second inlet 34_1 into which the refrigerant flows.

The first connection pipe 31 connects the first outlet 31_1 to the first inlet 33_1 and communicates the first space 21 with the third space 23 . The second connection pipe 32 connects the second outlet 32_1 to the second inlet 34_1 and communicates the second space 22 with the third space 23 . The second outflow port 32_1 is provided above the second partition 36 .

Note that the first outlet 31_1 and the first inlet 33_1 may be directly connected without using the first connection pipe 31. Also, the second outlet 32_1 and the second inlet 34_1 may be directly connected without using the second connecting pipe 32 .

Further, the sum of the number of first heat transfer tubes 3_1 connected to the first space 21 and the number of the first heat transfer tubes 3_1 connected to the second space is greater than the number of second heat transfer tubes 3_2. .

<Action>
Next, the operation of the air conditioner 200 will be described.
<Heating operation>
First, the operation of the air conditioner 200 during heating operation will be described. The high-temperature and high-pressure gas refrigerant compressed by the compressor 14 passes through a four-way valve (not shown) and flows into the indoor heat exchanger 16 functioning as a condenser.

The high-temperature, high-pressure gas refrigerant that has flowed into the indoor heat exchanger 16 is cooled while supplying heat to the indoor air, and flows out of the indoor heat exchanger 16 as a low-temperature liquid refrigerant. The liquid refrigerant flowing out of the indoor heat exchanger 16 is decompressed by the expansion device 17 to become a low-temperature, low-pressure gas-liquid two-phase refrigerant, and flows into a distributor (not shown) of the outdoor heat exchanger 10 functioning as an evaporator.

The low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed into the distributor of the outdoor heat exchanger 10 is distributed to the second heat transfer tubes 3_2. The refrigerant flowing through the second heat transfer pipe 3_2 is heated by the outdoor air to evaporate, and flows through the first connection pipe 31 and the second connection pipe 32 through the first heat transfer pipe 3_1. The refrigerant flowing through the first heat transfer tube 3_1 is heated by the outdoor air, evaporates, becomes a low-pressure gas refrigerant, and flows out from the first heat transfer tube 3_1. The low-pressure gas refrigerant that has flowed out of the first heat transfer pipe 3_1 flows out of the outdoor heat exchanger 10 after being merged in a union pipe (not shown). The low-pressure gas refrigerant that has flowed out of the outdoor heat exchanger 10 is sucked into the compressor 14 after passing through a four-way valve (not shown). The low-pressure gas refrigerant sucked into the compressor 14 is again compressed by the compressor 14 into high-temperature and high-pressure gas refrigerant.

<Cooling operation>
Next, the operation of the air conditioner 200 during cooling operation will be described.
The high-temperature, high-pressure gas refrigerant compressed by the compressor 14 passes through a four-way valve (not shown) and flows into a confluence pipe (not shown) of the outdoor heat exchanger 10 that functions as a condenser.

The high-temperature and high-pressure gas refrigerant that has flowed into the junction pipe of the outdoor heat exchanger 10 is distributed to the first heat transfer pipes 3_1 of the outdoor heat exchanger 10. Then, the refrigerant flowing through the first heat transfer pipe 3_1 is cooled by the outdoor air, condensed, becomes a low-temperature liquid refrigerant, and flows through the second heat transfer pipe 3_2 via the first connection pipe 31 and the second connection pipe 32. , flows out from the second heat transfer tube 3_2.

The low-temperature liquid refrigerant that has flowed out of the second heat transfer pipe 3_2 flows out of the outdoor heat exchanger 10 after joining at a distributor (not shown). The liquid refrigerant flowing out of the outdoor heat exchanger 10 is depressurized by the expansion device 17 to become a low-temperature, low-pressure gas-liquid two-phase refrigerant, and flows into the indoor heat exchanger 16 functioning as an evaporator. The low-temperature, low-pressure gas-liquid two-phase refrigerant that has flowed into the indoor heat exchanger 16 evaporates while absorbing heat from the indoor air, and flows out of the indoor heat exchanger 16 as a low-pressure gas refrigerant. The low-pressure gas refrigerant flowing out of the indoor heat exchanger 16 is sucked into the compressor 14 after passing through a four-way valve (not shown), where it is again compressed into a high-temperature and high-pressure gas refrigerant.

In the air conditioner 200 configured in this way, when the outdoor heat exchanger 10 functions as a condenser, the gas refrigerant exchanges heat with the leeward airflow in the first heat exchanger 11, and changes from a gas state to a gas-liquid state. phase changes. The refrigerant changed to the gas-liquid two-phase state flows from the first heat transfer tubes 3_1 of the first heat exchanger 11 into the first space 21 and the second space 22 of the first intermediate header 1 . This gas-liquid two-phase refrigerant is mixed inside the first space 21 and the second space 22, respectively, and then flows from the first space 21 and the second space 22 through the first connecting pipe 31 and the second connecting pipe 32, respectively. It flows into the third space 23 of the second intermediate header 2 of the second heat exchanger 12 . In the third space 23, the gas-liquid two-phase refrigerant flowing from the first connecting pipe 31 and the second connecting pipe 32 is mixed and divided into the heat transfer tubes 3 of the second heat exchanger 12 to exchange heat with the upwind airflow. .

<effect>
Next, effects of the first intermediate header 1 and the second intermediate header 2 of the outdoor heat exchanger 10 according to Embodiment 1 will be described. First, with reference to FIG. 4, a conventional outdoor heat exchanger 10, which is a comparison target of the outdoor heat exchanger 10 according to Embodiment 1, will be described.

FIG. 4 is a longitudinal sectional view showing refrigerant flows around the first intermediate header 1 and the second intermediate header 2 of the conventional outdoor heat exchanger 10. FIG.

In the conventional outdoor heat exchanger 10, the first heat transfer tubes 3_1 of the first heat exchanger 11 on the downstream side of the airflow are arranged with a specified interval in the vertical direction and connected to the first intermediate header 1. The second heat transfer tubes 3_2 of the second heat exchanger 12 on the upstream side of the airflow are arranged at regular intervals in the vertical direction and connected to the second intermediate header 2 . The first intermediate header 1 and the second intermediate header 2 are connected by a first connecting pipe 31 .

The gaseous refrigerant that has flowed into the first heat exchanger 11 exchanges heat with the downstream air stream, enters a two-phase state, and flows into the first intermediate header 1 . At this time, the airflow passing through the first heat exchanger 11 is increased in velocity between the first heat transfer tube 3_1 and the fins 4 provided on the upper side by the blower 13 provided in the top-blowing housing that blows air upward. The velocity of the wind flowing between the first heat transfer tube 3_1 and the fins 4 provided on the lower side becomes smaller. From the outlet of the first heat transfer tube 3_1 on the upper side, the liquid-based refrigerant 102 having a larger mass flow rate ratio of the liquid refrigerant than the outlet on the lower side flows into the inside of the first intermediate header 1 . From the outlet of the first heat transfer tube 3_1 on the lower side, the gas-based refrigerant 103 having a larger mass flow rate ratio of the gas refrigerant than the outlet on the upper side flows into the inside of the first intermediate header 1 .

At this time, since the liquid refrigerant 100 has a higher density than the gas refrigerant 101 , it falls downward inside the first intermediate header 1 . In the lower portion of the first space 21 , the driving force for causing the refrigerant to flow upward is the inertial force of the refrigerant flowing out from the first heat transfer tube 3_1 downstream of the lower portion of the first space 21 and upstream of the refrigerant flow. In the lower portion inside the first intermediate header 1 where the flow rate of the refrigerant is small, the inertial force of the refrigerant is small, and the liquid refrigerant that has fallen is not lifted upward, causing a liquid stagnation 104 . Especially in low-load operation, the flow rate of the refrigerant is small, and the inertial force of the refrigerant in the horizontal direction in the first heat transfer tube 3_1 is small. A liquid backflow 105 occurs.

Therefore, in the conventional outdoor heat exchanger 10, under conditions where the amount of refrigerant circulating in the refrigeration cycle circuit is small, such as during low-capacity operation of the air conditioner 200, the flow of the refrigerant is obstructed, causing the refrigerant to stagnate and flow backward 105. occurs. As a result, the heat exchange area of the first heat exchanger 11 becomes smaller, and the heat exchange performance of the condenser deteriorates.

FIG. 5 is a longitudinal sectional view showing refrigerant flows around the first intermediate header 1 and the second intermediate header of the outdoor heat exchanger 10 according to the first embodiment.

In the outdoor heat exchanger 10 according to Embodiment 1, the first intermediate header 1 is partitioned into the first space 21 and the second space 22 by the first partition 35 . Of the first heat transfer tubes 3_1 connected to the first intermediate header 1, at least one first heat transfer tube 3_1 is connected to the first space 21 from above. At least two or more first heat transfer tubes 3_1 provided on the lower side are connected to the second space 22 .

Therefore, the liquid-based refrigerant 102 flowing out from the upper first heat transfer tubes 3_1 does not enter the second space 22 inside the first intermediate header 1 . The liquid-based refrigerant 102 flows into the third space 23 of the second intermediate header 2 via the first connecting pipe 31 . As a result, the liquid stagnation 104 inside the second space 22 is reduced, a region for heat exchange is secured, and the heat exchange performance of the condenser is improved.

　It is particularly effective in low-load operation where the refrigerant flow rate is small. Note that in Embodiment 1, the flow rate of refrigerant flowing through the second connection pipe 32 is the sum of the flow rates of refrigerant flowing from the plurality of first heat transfer tubes 3_1 connected to the second space 22 . In addition, since the flow path diameter of the second connection pipe 32 can be designed without depending on the flow path diameter of the first heat transfer tube 3_1, backflow 105 of the liquid from the third space 23 to the second space 22 can be suppressed (see FIG. 4).

FIG. 6 is a conceptual schematic diagram showing the flow rate of refrigerant flowing into the first intermediate header 1 of the conventional outdoor heat exchanger 10 and the wind velocity distribution. FIG. 6 is a white bar graph showing the flow rate of the refrigerant flowing through the first heat transfer tube 3_1 connected to the conventional first intermediate header 1 for each height of the heat transfer tube. It is a figure which shows distribution with a solid line.

FIG. 7 is a conceptual schematic diagram showing the flow rate of refrigerant flowing into the first intermediate header 1 and the wind speed distribution of the outdoor heat exchanger 10 according to the first embodiment. FIG. 7 shows the flow rate of the refrigerant flowing through the first heat transfer tube 3_1 connected to the first intermediate header 1 according to Embodiment 1 by a black bar graph for each height of the heat transfer tube. It is a figure which shows the wind speed distribution of a direction with a solid line.

By the way, the gas-liquid two-phase refrigerant has the characteristic that when the gas refrigerant is large, the volume flow rate of the refrigerant is large and the refrigerant pressure loss is large, and when the liquid refrigerant is large, the refrigerant volume flow rate is small and the refrigerant pressure loss is small.

As shown in FIG. 4 , in the conventional outdoor heat exchanger 10 , the refrigerants at the outlets of the first heat transfer tubes 3_1 are mixed at the outlet of the first intermediate header 1 and mixed through the first connecting pipe 31 to the second intermediate header 2 . , the refrigerant flow rate difference between the first heat transfer tubes 3_1 is small as shown in FIG. On the other hand, in the top-blowing housing, the wind speed is high on the upper side where the air flow path length is short, and the wind speed is low on the lower side where the air flow path length is long. As a result, the difference between the wind velocity distribution and the refrigerant flow rate distribution becomes large, which is a factor in the deterioration of performance.

On the other hand, in the outdoor heat exchanger 10 according to Embodiment 1, the first space 21, which is the outlet of the upper first heat transfer tube 3_1, and the second space 22, which is the outlet of the lower first heat transfer tube 3_1, are not communicated with each other. partitioned. Therefore, as shown in FIG. 7, the flow rate of the refrigerant in the first heat transfer tube 3_1 connected to the first space 21 into which the liquid-based refrigerant 102 flows is the first It increases with respect to the refrigerant flow rate of the heat transfer tube 3_1. Therefore, the divergence between the wind speed distribution and the refrigerant flow rate distribution is reduced, and the heat exchange performance is improved.

FIG. 8 is a performance curve for the operating load of the outdoor heat exchanger 10 according to Embodiment 1. FIG. The horizontal axis indicates the ratio of cooling capacity to the maximum cooling capacity, and the vertical axis indicates the ratio of each operating capacity to the theoretical maximum performance of the outdoor heat exchanger 10 . In FIG. 8, the solid line indicates the characteristic curve of the first embodiment, and the dashed line indicates the conventional characteristic curve.

In the conventional configuration, liquid stagnation 104 (see FIG. 4) occurred in the first intermediate header 1, especially during low-load operation, resulting in performance degradation. In the configuration of Embodiment 1, the performance of the outdoor heat exchanger 10 is improved due to the effect of suppressing liquid retention, particularly during low-load operation. Furthermore, by matching the refrigerant distribution of the first heat transfer tube 3_1 with the wind speed distribution of the top-blowing housing, the performance of the outdoor heat exchanger 10 from low load to high load operation is improved, and the energy saving performance of the air conditioner 200 is improved. improves.

Even if the outdoor unit 201 is not a top-blowing housing, by mounting the outdoor heat exchanger 10, the liquid refrigerant falling to the lower part of the second space 22 of the first intermediate header 1 is reduced, so the performance is improved. It works. Furthermore, when the outdoor heat exchanger 10 is mounted in the top-blowing housing, a large amount of liquid refrigerant is formed on the upper side of gravity during cooling operation. For this reason, compared with the conventional configuration, the amount of liquid refrigerant falling into the lower portion of the second space 22 of the first intermediate header 1 is reduced for the same capacity, and the performance improvement effect is large.

The air conditioner 200 described above is an example of the air conditioner 200 according to the first embodiment. For example, the outdoor heat exchanger 10 may be installed in the indoor unit 202 of the air conditioner 200. Also, even if the number of divided spaces in the first intermediate header 1 is three or more, there is no problem with the effect, and it is a design item selected from the improvement effect and the manufacturing cost. In FIG. 3, the first space 21 and the second space 22 are partitioned by the first partition 35, but the effect can be obtained even if the first space 21 and the second space 22 are formed by separate headers. Absent.

Also, for example, the number of outdoor units 201 and indoor units 202 is not limited to one, and a plurality of them may be provided in the air conditioner 200 . Moreover, the type of refrigerant circulating in the refrigeration cycle circuit of the air conditioner 200 is not particularly limited. For example, the refrigerant includes R32, R410A, or at least refrigerants having a lower gas density relative to R32 refrigerants, including olefinic refrigerants, propane, or DME (dimethyl ether). With such a refrigerant, the deviation between the wind speed distribution and the refrigerant distribution due to the pressure loss of the gas refrigerant can be suppressed, so the performance improvement effect is greater.

The first heat transfer tube 3_1 and the second heat transfer tube 3_2 of the outdoor heat exchanger 10 are not limited to circular heat transfer tubes, and the cross section orthogonal to the axial direction of the first heat transfer tube 3_1 and the second heat transfer tube 3_2 Various heat transfer tubes such as a flat heat transfer tube whose long axis is along the air flow direction can be used. In particular, in the configuration in which the flat heat transfer tubes are directly inserted into the first intermediate header 1, the flow path diameter in the vertical direction of the header is larger than the length of the long axis of the flat tubes, so the cross-sectional area of the flow path is increased. As a result, the flow velocity in the second space 22 is reduced, and the amount of liquid refrigerant stagnation 104 is increased.

2, 3, and 5, the sum of the number of first heat transfer tubes 3_1 connected to the first space 21 and the number of first heat transfer tubes 3_1 connected to the second space 22 is the third The number of heat transfer tubes connected to the space may be greater than or equal to that of the heat transfer tubes.

FIG. 9 is a schematic diagram showing an example of the refrigerant channel configuration of the outdoor heat exchanger 10 according to Embodiment 1. FIG. As shown in FIG. 9, the outdoor heat exchanger 10 is composed of a parallel flow condenser in which two or more rows of headers are provided at both ends of heat transfer tubes. The sum of the number of first heat transfer tubes 3_1 connected to the first space 21 and the number of first heat transfer tubes 3_1 connected to the second space 22 is greater than the number of second heat transfer tubes 3_2 connected to the third space 23. . In such a configuration, the liquid refrigerant in the lower portion of the first intermediate header 1 needs to flow upward, so the application of this configuration has a large improvement effect.

Further, as shown in FIGS. 2, 3 and 5, the first connecting pipe 31 connecting the first space 21 and the third space 23 has an average height of the first heat transfer pipe 3_1 connected to the first space 21. It is provided below the height. The average height is the average height of all the first heat transfer tubes 3_1 connected to the first space 21 in the vertical direction. With such a configuration, it is possible to suppress retention of the liquid refrigerant inside the first space 21, so that the performance improvement effect is large.

However, even if the first connection pipe 31 is arranged higher than the average height of the first heat transfer pipe 3_1, if the lower part of the first space 21 is provided above the lower part of the third space 23, the liquid refrigerant can be flows out from the first space 21, there is no problem in improving the performance.

Therefore, according to the outdoor heat exchanger 10 of Embodiment 1, it is possible to suppress liquid retention under the gravity of the first heat exchanger 11 and the first intermediate header 1 . In a configuration where the first intermediate header 1 does not have the first partition 35, as in the conventional art, the liquid refrigerant that has fallen from the upper side of the first intermediate header 1 due to gravity cannot be lifted up only by the refrigerant in the lowermost heat transfer tube in the direction of gravity. Liquid stays, especially at intermediate loads. In the configuration of the outdoor heat exchanger 10 of Embodiment 1, the first intermediate header 1 is provided with the first partition 35 . The liquid-based refrigerant in the first space 21 and the gas-based refrigerant in the second space 22 are joined in the third space 23 of the second intermediate header 2 by the first connection pipe 31 and the second connection pipe 32, respectively. As a result, it is possible to suppress liquid from falling in the third space 23 with the refrigerant for the plurality of second heat transfer tubes 3_2. Therefore, it is possible to mix the gas-liquid refrigerant in the third space 23 while suppressing the retention of the liquid in the outdoor heat exchanger 10, thereby improving the cooling performance.

Embodiment 2.
In Embodiment 2, items that are not particularly described are the same as those in Embodiment 1, and the same functions and configurations are described using the same reference numerals.

FIG. 10 is a longitudinal sectional view showing the first intermediate header 1 and the second intermediate header 2 of the outdoor heat exchanger 10 according to Embodiment 2. FIG.

In the outdoor heat exchanger 10 according to Embodiment 2, in Embodiment 1, the third space 23 is located below the third space 23 and connected to at least one second heat transfer tube 3_2 separated from the third space 23. 4 spaces 24 are provided in the second intermediate header 2 . A first partition 35 that partitions the first space 21 and the second space 22 is provided above a second partition 36 that partitions the third space 23 and the fourth space 24 . The first partition 35 and the second partition 36 are plate members.

By configuring the outdoor heat exchanger 10 in this way, the head difference between the first partition 35 and the second partition 36 causes liquid refrigerant to flow from the first space 21 to the third space 23 via the first connection pipe 31 . of the liquid is promoted to suppress the retention of the liquid inside the first space 21 . Thereby, the cooling performance of the air conditioner 200 is improved.

Embodiment 3.
In Embodiment 3, items that are not particularly described are the same as those in

Embodiments

1 and 2, and the same functions and configurations are described using the same reference numerals.

11 is a longitudinal sectional view showing the first intermediate header 1 and the second intermediate header 2 of the outdoor heat exchanger 10 according to Embodiment 3. FIG. Embodiment 3 is different from Embodiment 2 in that the second outlet 32_1 in the second space 22 of the first intermediate header 1 of the second connection pipe 32 is the third space separating the third space 23 and the fourth space 24. It is a configuration provided above the second partition 36 . The second connection pipe 32 connects the second space 22 of the first intermediate header 1 and the third space 23 of the second intermediate header 2 .

In the outdoor heat exchanger 10 configured in this way, the head difference between the second outlet 32_1 in the second space 22 and the second partition 36 causes the liquid refrigerant to flow back 105 (see FIG. 4) into the second space 22. ) is suppressed, and the cooling performance of the air conditioner 200 is improved.

Embodiment 4.
In Embodiment 4, items that are not particularly described are the same as those in Embodiment 3, and the same functions and configurations are described using the same reference numerals.

FIG. 12 is a cross-sectional top view of the first intermediate header 1 and the second intermediate header 2 according to Embodiment 4. FIG. 13 is an enlarged cross-sectional view taken along the line AA of FIG. 12. FIG.

In FIG. 12, 71 indicates the central axis of the first intermediate header 1 in the extending direction, and 72 indicates the central axis of the second intermediate header 2 in the extending direction. 73 indicates the central axis of the connecting pipe. Two dashed lines extending from the central axis 72 of the second intermediate header 2 in the extending direction indicate the range in which the pipe wall 38 of the first intermediate header 1 can be seen. In FIG. 13 , 111 indicates the refrigerant flow from the first space 21 to the

third space

23 and 112 indicates the refrigerant flow from the second space 22 to the third space 23 .

In Embodiment 4, the first outflow port 31_1 is the first outlet in the range in which the first intermediate header 1 can be seen when viewed from the central axis 72 in the extending direction of the first intermediate header and the extending direction of the second intermediate header 2 . It is provided on the tube wall 38 of the intermediate header 1 . That is, the first outflow port 31_1 is provided in the pipe wall 38 of the first intermediate header 1 on the second intermediate header 2 side.

By configuring the first intermediate header 1 as in the fourth embodiment, the path length of the first connecting pipe 31 from the first space 21 to the third space 23 is shortened, and the flow of the refrigerant flow 111 is promoted. Retention of the liquid refrigerant in the first space 21 is suppressed. Further, the route length of the second connection pipe 32 from the second space 22 to the third space 23 is shortened, and the coolant is transported to the third space 23 without greatly reducing the inertia force of the coolant flow 112 . Therefore, a large amount of the gas-based refrigerant is supplied upward due to gravity in the third space 23, and the refrigerant can be distributed according to the wind speed distribution of the top-blowing housing.

FIG. 14 is an enlarged sectional view taken along the line AA of FIG. 12, showing a first modification of the first intermediate header 1 and the second intermediate header 2 according to the fourth embodiment.

In the modification of the fourth embodiment shown in FIG. 14, the height of the first outlet 31_1 to the third space 23 in the first space 21 of the first intermediate header 1 is is the same as or higher than the height position of the first inlet 33_1 from the first space 21 in .

By configuring the first intermediate header 1 as in this modification, the flow of the refrigerant flow 111 is promoted due to the head difference between the height position of the first outlet 31_1 and the first inlet 33_1, and the first space 21 Stagnation of the liquid refrigerant inside is suppressed. Thereby, the performance of the condenser is improved, and the cooling performance of the air conditioner 200 is improved.

14, the height position of the second outflow port 32_1 to the third space 23 in the second space 22 of the first intermediate header 1 is the second It is a higher configuration than the height position of the partition 36 .

As in this modification, by providing the second outlet 32_1 upward in the gravitational direction than the upper portion of the second partition 36, the backflow 105 (see FIG. 4) of the liquid refrigerant from the third space 23 to the second space 22 is prevented. reduced. Thereby, the performance of the condenser is improved, and the cooling performance of the air conditioner 200 is improved. In particular, the improvement effect is large in low-load operation where the refrigerant flow velocity becomes small.

FIG. 15 is an enlarged sectional view taken along line AA of FIG. 12, showing a second modification of the first intermediate header 1 and the second intermediate header 2 according to the fourth embodiment. As shown in FIG. 15, in the second modification of the fourth embodiment, the first outlet 31_1 and the second outlet 32_1 are partitioned by the first partition 35 . That is, the first partition 35 is provided within the height range of one opening provided in the tube wall of the first intermediate header 1, and the upper side of the first partition 35 of this opening is the first outlet 31_1. , the lower side is the second outflow port 32_1.

As long as the first outflow port 31_1 and the second outflow port 32_1 form different outflow ports as in this modification, the first connection pipe 31 and the second connection pipe 32 may be integrally configured with one pipe. good. In this modified example, it is not necessary to raise the liquid refrigerant above the first partition 35 until the refrigerant is supplied from the first space 21 to the third space 23, so the retention of the liquid refrigerant in the first space 21 is suppressed. can. Thereby, the performance of the condenser is improved, and the cooling performance of the air conditioner 200 is improved. In particular, the improvement effect is large in low-load operation where the refrigerant flow velocity becomes small.

The embodiment is presented as an example and is not intended to limit the scope of claims. Embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the gist of the embodiments. These embodiments and modifications thereof are included in the scope and gist of the embodiments.

1 first intermediate header, 2 second intermediate header, 3_1 first heat transfer tube, 3_2 second heat transfer tube, 4 fins, 10 outdoor heat exchanger, 11 first heat exchanger, 12 second heat exchanger, 13 blower, 14 compressor, 16 indoor heat exchanger, 17 expansion device, 18 refrigerant pipe, 21 first space, 22 second space, 23 third space, 24 fourth space, 31 first connection pipe, 31_1 first outlet, 32 second connection pipe, 32_1 second outlet, 33_1 first inlet, 34_1 second inlet, 35 first partition, 36 second partition, 38 pipe wall, 71 center axis of the first intermediate header 1 in the extending direction , 72 Center axis in extension direction of second

intermediate header

2, 73 Center axis of connecting pipe, 90 Gravity direction, 100 Liquid refrigerant, 101 Gas refrigerant, 102 Liquid-based refrigerant, 103 Gas-based refrigerant, 104 Retention of liquid refrigerant, 105 Backflow of liquid refrigerant, 111 refrigerant flow from the first space to the third space, 112 refrigerant flow from the second space to the third space, 200 air conditioner, 201 outdoor unit, 202 indoor unit, 203 upward blowing housing, 300 Wind speed distribution, AF air flow direction.

Claims

a first intermediate header extending in the direction of gravity;
a first heat transfer tube connected to the first intermediate header and performing heat exchange between refrigerant and air;
a first heat exchanger having a first partition that divides the inside of the first intermediate header into a first space and a second space arranged below the first space;
a second intermediate header arranged in parallel on the windward side of the first heat exchanger and extending in the direction of gravity;
a second heat transfer tube connected to the second intermediate header and performing heat exchange between the refrigerant and the air;
a second heat exchanger having a second partition that divides the inside of the second intermediate header into a third space and a fourth space arranged below the third space;
There are a plurality of the first heat transfer tubes, and the plurality of the first heat transfer tubes includes the first heat transfer tube connected to the first space and the first heat transfer tube connected to the second space. have
The first intermediate header forming the first space is provided with a first outlet through which the refrigerant flows,
The first intermediate header forming the second space is provided with a second outlet through which the refrigerant flows,
The second intermediate header is connected to the first intermediate header, and has a first inlet through which the refrigerant flows into the third space from the first outlet, and a first outlet through which the refrigerant flows into the third space from the second outlet. and a second inlet that flows into the space.
2. The first heat transfer tube and the second heat transfer tube according to claim 1, wherein the flat heat transfer tube has a long axis of a cross section orthogonal to an axial direction of the first heat transfer tube and the second heat transfer tube along an airflow direction. Heat exchanger.
The second heat transfer tube is connected to the third space,
2. The sum of the number of said first heat transfer tubes connected to said first space and the number of said first heat transfer tubes connected to said second space is greater than the number of said second heat transfer tubes. Or the heat exchanger according to 2.
A first connection pipe that connects the first outlet and the first inlet,
The heat exchanger according to any one of claims 1 to 3, wherein the first connection pipe is provided below an average height of the first heat transfer pipes connected to the first space.
The heat exchanger according to any one of claims 1 to 4, wherein the first partition is provided above the second partition.
The heat exchanger according to any one of claims 1 to 5, wherein the second outlet is provided above the second partition.
5. The heat exchanger according to claim 4, further comprising a second connecting pipe connecting said second outlet and said second inlet.
3. The first outflow port is provided in the tube wall of the first intermediate header within a range where the first intermediate header can be seen from the central axis of the second intermediate header when viewed in the extending direction of the first intermediate header. The heat exchanger according to any one of 1 to 7.
The heat exchanger according to any one of claims 1 to 8, wherein the first outlet is provided at a position higher than the first inlet.
The refrigerant comprises R32, R410A, or at least a refrigerant having a lower gas density than R32 refrigerants, including olefinic refrigerants, propane, and DME.
A heat exchanger according to any one of claims 1-9.
An air conditioner comprising the heat exchanger according to any one of claims 1 to 10.
The air conditioner is
a blower for blowing air upward;
a top-blowing housing including an outlet for discharging the air blown by the blower,
The air conditioner according to claim 11, wherein the heat exchanger is mounted on the housing.