JP7566155B2 - Heat exchanger and air conditioning device - Google Patents

Description

The present disclosure relates to a heat exchanger having a first heat exchanger and a second heat exchanger, and an air conditioning device equipped with such a heat exchanger.

The 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 exchanges heat between the incoming gas refrigerant and the outside air. The refrigerant that has undergone heat exchange passes through a gas-liquid two-phase state and flows out of the condenser as a liquid refrigerant. In this case, there is a means for improving the heat exchanger performance by providing a group of heat transfer tubes on the windward side and a group of heat transfer tubes on the leeward side, folding back one end of the group of heat transfer tubes, and flowing the refrigerant that has become a gas-liquid two-phase state on the leeward side to the windward side. As a conventional folding back means, there is a method in which the refrigerant is joined at the header at the outlet of the heat transfer tube on the leeward side and the refrigerant is supplied to the header at the inlet of the heat transfer tube on the windward side (see, for example, Patent Document 1).

JP 2019-132537 A

In a conventional refrigerant circuit configuration, when a heat exchanger serving as a condenser is mounted in a top-blowing housing and forms an air velocity distribution, a large amount of liquid phase is generated in the upper heat transfer tubes. However, if the heat transfer tube outlets are connected to each other in the header, the liquid refrigerant that falls from the upper heat transfer tubes in the header cannot be lifted by the refrigerant in the heat transfer tube at the bottom in the direction of gravity alone, and the liquid refrigerant accumulates, resulting in reduced performance, especially at intermediate loads.

The present disclosure has been made in consideration of the above-mentioned situation, and aims to provide a heat exchanger and an air conditioning device having a first heat exchanger and a second heat exchanger that can improve heat exchange performance.

The heat exchanger according to the present disclosure 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 the refrigerant and the air, and a first partition dividing the interior of the first intermediate header into a first space and a second space arranged below the first space, and a second heat exchanger arranged upwind of the first heat exchanger, the 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 the refrigerant and the air, and a second partition dividing the interior of the second intermediate header into a third space and a fourth space arranged below the third space. the first intermediate header constituting the first space is provided with a first outlet through which the refrigerant flows out, and the first intermediate header constituting the second space is provided with a second outlet through which the refrigerant flows out, and 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 second inlet through which the refrigerant flows into the third space from the second outlet.

According to the present disclosure, the second intermediate header is connected to the first intermediate header and has a first inlet through which liquid-based refrigerant flows from the first outlet into the third space, and a second inlet through which gas-based refrigerant flows from the second outlet into the third space. This allows the liquid-based refrigerant and the gas-based refrigerant to mix in the third space, preventing the liquid refrigerant from falling to the bottom of the second intermediate header, thereby improving the heat exchange performance of the cooling system.

1 is a configuration diagram of an air conditioning device according to a first embodiment. 1 is a perspective see-through view of an outdoor heat exchanger according to a first embodiment. FIG. 3 is a vertical cross-sectional view showing the periphery of a first intermediate header and a second intermediate header of the outdoor heat exchanger according to the first embodiment. FIG. 10 is a vertical cross-sectional view showing a refrigerant flow around a first intermediate header and a second intermediate header of a conventional outdoor heat exchanger. FIG. 4 is a vertical cross-sectional view showing a refrigerant flow around a first intermediate header and a second intermediate header of the outdoor heat exchanger according to the first embodiment. FIG. 1 is a conceptual schematic diagram showing a flow rate and wind speed distribution of a refrigerant flowing into a first intermediate header of a conventional outdoor heat exchanger. 5 is a conceptual schematic diagram showing a flow rate and wind speed distribution of a refrigerant flowing into a first intermediate header of the outdoor heat exchanger according to the first embodiment. FIG. 4 is a performance curve versus operating load in the outdoor heat exchanger according to the first embodiment. 2 is a schematic diagram illustrating an example of a refrigerant flow path configuration of an outdoor heat exchanger according to the first embodiment. 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 a second embodiment. 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 a third embodiment. FIG. A top cross-sectional view of a first intermediate header and a second intermediate header according to embodiment 4. 13 is an enlarged cross-sectional view along the line AA in FIG. 12. 13 is an enlarged cross-sectional view taken along the line AA in FIG. 12 , showing a first modified example of the first intermediate header and the second intermediate header according to the fourth embodiment. 13 is an enlarged cross-sectional view taken along the line AA in FIG. 12, showing a second modified example of the first intermediate header and the second intermediate header according to the fourth embodiment.

In each of the following embodiments, an example of a heat exchanger and air conditioning apparatus according to the present disclosure will be described with reference to the drawings. Note that in each of the following drawings, configurations with 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 conditioning apparatus according to the present disclosure are not limited to the configurations described in the following embodiments. Furthermore, combinations of configurations are not limited to only combinations in the same embodiment, but configurations described in different embodiments may be combined. In each of the following drawings, the relationship in size of each component 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-conditioning apparatus 200 according to the first embodiment. The open and closed arrows along the refrigerant pipes 18 in FIG. 1 indicate the flow direction of the refrigerant during cooling operation. The open and closed arrows indicate that the refrigerant is in a gaseous state, and the closed arrows indicate that the refrigerant is in a liquid state. The shaded arrows near the first intermediate header 1 and the second intermediate header 2 typically indicate that the refrigerant is in a gas-liquid two-phase state. The flow of the refrigerant when the outdoor heat exchanger 10 functions as a condenser is shown. In FIG. 1, the direction of AF indicates the air flow direction, and the direction of the arrow 90 indicates the direction of gravity.

The air conditioning device 200 includes a compressor 14 that compresses the refrigerant, an outdoor heat exchanger 10 that functions as a condenser, a throttling device 17 that reduces the pressure of the refrigerant to expand it, and an indoor heat exchanger 16 that functions as an evaporator. The compressor 14, the outdoor heat exchanger 10, the throttling device 17, and the indoor heat exchanger 16 are connected in sequence by refrigerant piping 18 to form a refrigeration cycle circuit.

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

The outdoor heat exchanger 10 has a first heat exchanger 11 and a second heat exchanger 12. The first heat exchanger 11 has 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 the refrigerant and the air. The second heat exchanger 12 is arranged upwind of the first heat exchanger 11 and has a second intermediate header 2 extending in the direction of gravity 90 and a second heat transfer tube 3_2 connected to the second intermediate header 2 and performing heat exchange between the refrigerant and the air.

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

Figure 2 is an oblique perspective view of the outdoor heat exchanger 10 according to embodiment 1. Figure 3 is a vertical cross-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. This Figure 3 is a vertical cross-sectional view parallel to the extension direction of the first heat transfer tube 3_1 and the second heat transfer tube 3_2.

As shown in Figure 2, the outdoor heat exchanger 10 is mounted in an upward-blowing housing 203 of an outdoor unit 201 equipped with a blower 13 that blows air upward. The upward-blowing housing 203 has an outlet at the top through which the air blown out from the blower 13 flows out. As shown in Figure 3, the outdoor heat exchanger 10 has a first heat exchanger 11 and a second heat exchanger 12 that is 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 tubes 3_1 extend horizontally and are arranged at specified intervals in the vertical direction. The second heat exchanger 12 has a plurality of second heat transfer tubes 3_2. The second heat exchanger 12 extends horizontally and is arranged at specified 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 by the outdoor air and condensed. In the first embodiment, as shown in FIG. 3, in order to promote heat exchange between the refrigerant and the outdoor air, a plurality of fins 4 are connected to the plurality of first heat transfer tubes 3_1, and a plurality of fins (not shown) are connected to the plurality of second heat transfer tubes 3_2.

The first heat exchanger 11 provided downstream in the airflow and the second heat exchanger 12 provided upstream in the airflow are connected in sequence via a first intermediate header 1 and a second intermediate header 2. The first intermediate header 1 is configured so that a first heat transfer tube 3_1 is inserted into a piping having a fixed volume. The second intermediate header 2 is configured so that a second heat transfer tube 3_2 is inserted into a piping having a fixed 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 divided 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 of the first heat transfer tubes 3_1 connected to the first intermediate header 1 are connected to the second space 22.

A first outlet 31_1 through which the refrigerant flows out is provided in the pipe wall of the first intermediate header 1 that constitutes the first space 21. A second outlet 32_1 through which the refrigerant flows out is provided in the pipe wall of the first intermediate header 1 that constitutes the second space 22.

The second intermediate header 2 is divided 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 that constitutes the third space 23 has a first inlet 33_1 and a second inlet 34_1 through 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 outlet 32_1 is provided above the second partition 36.

The first outlet 31_1 and the first inlet 33_1 may be directly connected without using the first connection pipe 31. The second outlet 32_1 and the second inlet 34_1 may be directly connected without using the second connection pipe 32.

In addition, 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 the second heat transfer tubes 3_2.

<Operation>
Next, the operation of the air conditioning device 200 will be described.
<Heating operation>
First, a description will be given of the operation during heating operation of the air conditioner 200. High-temperature, 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, which functions as a condenser.

The high-temperature, high-pressure gas refrigerant that flows into the indoor heat exchanger 16 is cooled while supplying heat to the indoor air, and becomes a low-temperature liquid refrigerant that flows out of the indoor heat exchanger 16. The liquid refrigerant that flows out of the indoor heat exchanger 16 is depressurized by the throttling 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 that functions as an evaporator.

The low-temperature, low-pressure, gas-liquid two-phase refrigerant that flows into the distributor of the outdoor heat exchanger 10 is distributed to the second heat transfer tube 3_2. The refrigerant flowing through the second heat transfer tube 3_2 is heated by the outdoor air and evaporated, and flows through the first heat transfer tube 3_1 via the first connecting pipe 31 and the second connecting pipe 32. The refrigerant flowing through the first heat transfer tube 3_1 is heated by the outdoor air and evaporated, becoming a low-pressure gas refrigerant and flowing out from the first heat transfer tube 3_1. The low-pressure gas refrigerant that flows out from the first heat transfer tube 3_1 flows out from the outdoor heat exchanger 10 after merging with a merging pipe not shown. The low-pressure gas refrigerant that flows out from 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 compressed again into a high-temperature, high-pressure gas refrigerant by the compressor 14.

<Cooling operation>
Next, the operation of the air conditioning device 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 junction pipe (not shown) of the outdoor heat exchanger 10 that functions as a condenser.

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

The low-temperature liquid refrigerant flowing out of the second heat transfer tube 3_2 is merged in a distributor (not shown) and then flows out of the outdoor heat exchanger 10. The liquid refrigerant flowing out of the outdoor heat exchanger 10 is decompressed by the throttling device 17 to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant, and flows into the indoor heat exchanger 16, which functions as an evaporator. The low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows 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 passes through a four-way valve (not shown) and is sucked into the compressor 14, where it is compressed again into a high-temperature, high-pressure gas refrigerant.

In the air conditioning device 200 configured in this manner, when the outdoor heat exchanger 10 functions as a condenser, the gas refrigerant exchanges heat with the downwind airflow in the first heat exchanger 11, changing from a gas state to a gas-liquid two-phase state. The refrigerant that has changed to a gas-liquid two-phase state flows from the first heat transfer tube 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 into the third space 23 of the second intermediate header 2 of the second heat exchanger 12 through the first connection pipe 31 and the second connection pipe 32, respectively. In the third space 23, the gas-liquid two-phase refrigerant that has flowed in from the first connection pipe 31 and the second connection pipe 32 is mixed and diverted to the heat transfer tube 3 of the second heat exchanger 12 to exchange heat with the upwind airflow.

＜Effects＞
Next, a description will be given of the effects of the first intermediate header 1 and the second intermediate header 2 of the outdoor heat exchanger 10 according to embodiment 1. First, a description will be given of a conventional outdoor heat exchanger 10, which is a comparison target for the outdoor heat exchanger 10 according to embodiment 1, with reference to Fig. 4 .

Figure 4 is a vertical cross-sectional view showing the refrigerant flow around the first intermediate header 1 and the second intermediate header 2 of a conventional outdoor heat exchanger 10.

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

The gas refrigerant that flows into the first heat exchanger 11 exchanges heat with the downstream airflow, and flows into the first intermediate header 1 in a two-phase state. At this time, the airflow passing through the first heat exchanger 11 increases in speed between the first heat transfer tube 3_1 and the fins 4 provided on the upper side due to the blower 13 provided in the up-blowing housing that blows air upward. The airflow speed between the first heat transfer tube 3_1 and the fins 4 provided on the lower side decreases. From the outlet of the upper first heat transfer tube 3_1, liquid-based refrigerant 102, which has a larger mass flow ratio of liquid refrigerant than the outlet on the lower side, flows into the first intermediate header 1. From the outlet of the lower first heat transfer tube 3_1, gas-based refrigerant 103, which has a larger mass flow ratio of gas refrigerant than the outlet on the upper side, flows into the first intermediate header 1.

At this time, the liquid refrigerant 100 has a higher density than the gas refrigerant 101, so it falls downward inside the first intermediate header 1. In the lower part of the first space 21, the driving force that flows the refrigerant upward is the inertial force of the refrigerant flowing out from the first heat transfer tube 3_1 upstream of the refrigerant flow, below the lower part of the first space 21. In the lower part of the first intermediate header 1, where the refrigerant flow rate is small, the inertial force of the refrigerant is small, and the liquid refrigerant that falls does not rise upward, causing liquid stagnation 104. In particular, during low-load operation, the refrigerant flow rate is small and the inertial force of the refrigerant in the horizontal direction inside the first heat transfer tube 3_1 is small, so the liquid refrigerant enters the lower part of the first space 21 into the lower first heat transfer tube 3_1, causing a liquid backflow 105.

For this reason, in the conventional outdoor heat exchanger 10, under conditions where the amount of refrigerant circulating in the refrigeration cycle circuit is small, such as when the air conditioning device 200 is operating at low capacity, the flow of the refrigerant is impeded, causing refrigerant stagnation and backflow 105. As a result, the heat exchange area of the first heat exchanger 11 becomes smaller, and the heat exchange performance of the condenser decreases.

Figure 5 is a vertical cross-sectional view showing the refrigerant flow around the first intermediate header 1 and the second intermediate header of the outdoor heat exchanger 10 in embodiment 1.

In the outdoor heat exchanger 10 according to the first embodiment, the first intermediate header 1 is partitioned into a first space 21 and a second space 22 by a first partition 35. At least one first heat transfer tube 3_1 is connected from the upper side to the first space 21 among the first heat transfer tubes 3_1 connected to the first intermediate header 1. 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 tube 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. This reduces the amount of liquid stagnation 104 inside the second space 22, ensures an area for heat exchange, and improves the heat exchange performance of the condenser.

The effect is particularly great in low-load operation where the refrigerant flow rate is small. In embodiment 1, the refrigerant flow rate flowing through the second connecting pipe 32 is the sum of the refrigerant flow rates flowing from the multiple first heat transfer tubes 3_1 connected to the second space 22. In addition, since the flow path diameter of the second connecting pipe 32 can be designed independently of the flow path diameter of the first heat transfer tube 3_1, backflow 105 of liquid from the third space 23 to the second space 22 can be suppressed (see FIG. 4).

Figure 6 is a conceptual schematic diagram showing the refrigerant flow rate and wind speed distribution flowing into the first intermediate header 1 of a conventional outdoor heat exchanger 10. Figure 6 shows the flow rate of refrigerant flowing into the first heat transfer tube 3_1 connected to the conventional first intermediate header 1 with a white bar graph for each height of the heat transfer tube, and the wind speed distribution in the height direction of the top-blowing housing with a solid line.

Figure 7 is a conceptual schematic diagram showing the refrigerant flow rate and wind speed distribution flowing into the first intermediate header 1 of the outdoor heat exchanger 10 according to embodiment 1. Figure 7 shows the flow rate of refrigerant flowing into the first heat transfer tube 3_1 connected to the first intermediate header 1 according to embodiment 1 for each height of the heat transfer tube as a black bar graph, and the wind speed distribution in the height direction of the top-blowing housing as a solid line.

However, gas-liquid two-phase refrigerants have the characteristic that when there is a lot of gas refrigerant, the refrigerant volumetric flow rate is large, resulting in large refrigerant pressure loss, and when there is a lot of liquid refrigerant, the refrigerant volumetric flow rate is small, resulting in small refrigerant pressure loss.

As shown in Figure 4, in the conventional outdoor heat exchanger 10, the refrigerant at the outlet of each first heat transfer tube 3_1 is mixed at the outlet of the first intermediate header 1 and flows into the second intermediate header 2 via the first connection pipe 31, so the difference in refrigerant flow rate for each first heat transfer tube 3_1 is small, as shown in Figure 6. On the other hand, in the upward-blowing housing, the wind speed is high on the upper side where the airflow path length is short, and the wind speed is low on the lower side where the airflow path length is long. This results in a large discrepancy between the wind speed distribution and the refrigerant flow rate distribution, which is a cause of performance degradation.

On the other hand, in the outdoor heat exchanger 10 according to the first embodiment, 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 partitioned so as not to communicate with each other. Therefore, as shown in FIG. 7, the refrigerant flow rate of the first heat transfer tube 3_1 connected to the first space 21 into which the liquid-based refrigerant 102 flows is greater than the refrigerant flow rate of the first heat transfer tube 3_1 connected to the second space 22 into which the gas-based refrigerant 103 flows. Therefore, the deviation between the wind speed distribution and the refrigerant flow rate distribution is reduced, improving the heat exchange performance.

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

In the conventional configuration, liquid stagnation 104 (see Figure 4) occurred in the first intermediate header 1, especially during low load operation, resulting in reduced performance. In the configuration of embodiment 1, the performance of the outdoor heat exchanger 10 is improved by suppressing liquid stagnation, especially during low load operation. Furthermore, by matching the refrigerant distribution of the first heat transfer tube 3_1 to the wind speed distribution of the top-blowing housing, the performance of the outdoor heat exchanger 10 is improved from low load to high load operation, and the energy saving properties of the air conditioning device 200 are improved.

Even if the outdoor unit 201 is not a top-blowing housing, by installing the outdoor heat exchanger 10, the amount of liquid refrigerant that falls to the bottom of the second space 22 of the first intermediate header 1 is reduced, resulting in a performance improvement effect. Furthermore, when the outdoor heat exchanger 10 is installed in a top-blowing housing, more liquid refrigerant is formed on the upper side due to gravity during cooling operation. Therefore, compared to the conventional configuration, less liquid refrigerant falls to the bottom of the second space 22 of the first intermediate header 1 per the same capacity, resulting in a large performance improvement effect.

The air conditioning device 200 described above is an example of an air conditioning device 200 according to embodiment 1. For example, the outdoor heat exchanger 10 may be mounted in the indoor unit 202 of the air conditioning device 200. Furthermore, the number of divided spaces in the first intermediate header 1 can be three or more without hindrance to effectiveness, and is a design matter selected based on improvement effects and manufacturing costs. In FIG. 3, the first space 21 and the second space 22 are separated by the first partition 35, but there is no hindrance to effectiveness even if the first space 21 and the second space 22 are configured as separate headers.

In addition, for example, the number of outdoor units 201 and indoor units 202 is not limited to one, and multiple units may be provided in the air conditioning device 200. In addition, the type of refrigerant circulating through the refrigeration cycle circuit of the air conditioning device 200 is not particularly limited. For example, the refrigerant includes R32, R410A, or at least an olefin-based refrigerant, a refrigerant having a lower gas density than the R32 refrigerant including propane or DME (dimethyl ether). With such a refrigerant, the deviation between the air speed distribution and the refrigerant distribution due to the pressure loss of the gas refrigerant can be suppressed, resulting in a greater performance improvement effect.

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 various heat transfer tubes can be used, such as flat heat transfer tubes whose major axis of the cross section perpendicular to the axial direction of the first heat transfer tube 3_1 and the second heat transfer tube 3_2 is along the airflow direction. In particular, in a configuration in which the flat heat transfer tube is directly inserted into the first intermediate header 1, the flow path diameter in the vertical direction of the header is larger than the major axis length of the flat tube, so the flow path cross-sectional area is large. As a result, the flow velocity in the second space 22 decreases, and the liquid refrigerant retention 104 increases, resulting in a large improvement effect due to this configuration.

Also, as shown in Figures 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 may be greater than or the same as the number of heat transfer tubes connected to the third space.

Figure 9 is a schematic diagram showing an example of the refrigerant flow path configuration of the outdoor heat exchanger 10 according to embodiment 1. As shown in Figure 9, the outdoor heat exchanger 10 is configured as a parallel flow condenser in which two or more rows of headers are provided at both ends of the 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 part of the first intermediate header 1 needs to flow upward, so the improvement effect of applying this configuration is significant.

2, 3 and 5, the first connection pipe 31 connecting the first space 21 and the third space 23 is provided below the average height of the first heat transfer tubes 3_1 connected to the first space 21. The average height is the average of the vertical heights of all the first heat transfer tubes 3_1 connected to the first space 21. This configuration can suppress the stagnation of liquid refrigerant inside the first space 21, resulting in a significant performance improvement effect.

However, even if the first connecting pipe 31 is positioned higher than the average height of the first heat transfer pipe 3_1, as long as the lower part of the first space 21 is located higher than the lower part of the third space 23, the liquid refrigerant will flow out of the first space 21 due to the siphon principle, and the performance improvement effect will not be impeded.

Therefore, according to the outdoor heat exchanger 10 of the first embodiment, it is possible to suppress liquid retention on the gravity side of the first heat exchanger 11 and the first intermediate header 1. In a conventional configuration in which the first intermediate header 1 does not have the first partition 35, the liquid refrigerant that falls from the gravity side in the first intermediate header 1 cannot be lifted only by the refrigerant in the heat transfer tube at the bottom in the gravity direction, and the liquid stagnates, especially at intermediate loads. In the configuration of the outdoor heat exchanger 10 of the first embodiment, the first partition 35 is provided in the first intermediate header 1. Then, the liquid-based refrigerant in the first space 21 is joined by the first connecting pipe 31, and the gas-based refrigerant in the second space 22 is joined by the second connecting pipe 32 in the third space 23 of the second intermediate header 2. As a result, the liquid can be suppressed from falling in the third space 23 by the refrigerant of the second heat transfer tubes 3_2. Therefore, it becomes possible to mix the gas and liquid refrigerant in the third space 23 while suppressing liquid stagnation in the outdoor heat exchanger 10, thereby improving cooling performance.

Embodiment 2.
In the second embodiment, items not specifically described are the same as those in the first embodiment, and the same functions and configurations are described using the same reference numerals.

Figure 10 is a longitudinal cross-sectional view showing the first intermediate header 1 and the second intermediate header 2 of the outdoor heat exchanger 10 of embodiment 2.

In the outdoor heat exchanger 10 according to the second embodiment, a fourth space 24 is provided in the second intermediate header 2 below the third space 23 in the first embodiment, and the fourth space 24 is connected to at least one second heat transfer tube 3_2 separated from the third space 23. The first partition 35 separating the first space 21 and the second space 22 is provided above the second partition 36 separating the third space 23 and the fourth space 24. The first partition 35 and the second partition 36 are plate-shaped members.

By configuring the outdoor heat exchanger 10 in this manner, the head difference between the first partition 35 and the second partition 36 promotes the flow of liquid refrigerant from the first space 21 to the third space 23 via the first connecting pipe 31, thereby suppressing the accumulation of liquid inside the first space 21. This improves the cooling performance of the air conditioning device 200.

Embodiment 3.
In the third embodiment, items not specifically described are the same as those in either the first or second embodiment, and the same functions and configurations are described using the same reference numerals.

Figure 11 is a vertical cross-sectional view showing the first intermediate header 1 and the second intermediate header 2 of the outdoor heat exchanger 10 according to embodiment 3. Unlike embodiment 2, embodiment 3 is configured such that the second outlet 32_1 in the second space 22 of the first intermediate header 1 of the second connection pipe 32 is provided above the second partition 36 that separates the third space 23 and the fourth space 24. 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 manner, the head difference between the second outlet 32_1 in the second space 22 and the second partition 36 suppresses the backflow 105 (see FIG. 4) of the liquid refrigerant into the second space 22, improving the cooling performance of the air conditioning device 200.

Embodiment 4.
In the fourth embodiment, items not specifically described are the same as those in the third embodiment, and the same functions and configurations are described using the same reference numerals.

Figure 12 is a top cross-sectional view of the first intermediate header 1 and the second intermediate header 2 relating to embodiment 4. Figure 13 is an enlarged cross-sectional view in the A-A direction of Figure 12.

In Figure 12, 71 indicates the central axis of the first intermediate header 1 in the extension direction, and 72 indicates the central axis of the second intermediate header 2 in the extension direction. 73 indicates the central axis of the connecting piping. Two dashed lines extending from the central axis 72 in the extension direction of the second intermediate header 2 indicate the range in which the pipe wall 38 of the first intermediate header 1 is visible. In Figure 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 the fourth embodiment, the first outlet 31_1 is provided in the pipe wall 38 of the first intermediate header 1 in a range where the first intermediate header 1 is visible when viewed from the central axis 72 in the extension direction of the first intermediate header and the extension direction of the second intermediate header 2. In other words, the first outlet 31_1 is provided in the pipe wall 38 on the second intermediate header 2 side of the first intermediate header 1.

By configuring the first intermediate header 1 as in embodiment 4, the path length of the first connection pipe 31 from the first space 21 to the third space 23 is shortened, the flow of the refrigerant flow 111 is promoted, and the retention of liquid refrigerant in the first space 21 is suppressed. In addition, the path length of the second connection pipe 32 from the second space 22 to the third space 23 is shortened, and the refrigerant is transported to the third space 23 without significantly reducing the inertial force of the refrigerant flow 112. Therefore, a large amount of 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.

Figure 14 is an enlarged cross-sectional view along the A-A direction in Figure 12, showing a first modified example of the first intermediate header 1 and the second intermediate header 2 relating to embodiment 4.

In a modified example of this embodiment 4 shown in Figure 14, the height of the first flow outlet 31_1 into the third space 23 in the first space 21 of the first intermediate header 1 is the same as or higher than the height position of the first flow inlet 33_1 from the first space 21 in the third space 23 of the second intermediate header 2.

By configuring the first intermediate header 1 as in this modified example, the flow of the refrigerant flow 111 is promoted by the head difference between the height position of the first outlet 31_1 and the first inlet 33_1, and the retention of liquid refrigerant in the first space 21 is suppressed. This improves the condenser performance and improves the cooling performance of the air conditioning device 200.

In addition, the modified example of embodiment 4 shown in Figure 14 is configured such that the height position of the second outlet 32_1 to the third space 23 in the second space 22 of the first intermediate header 1 is higher than the height position of the second partition 36 of the second intermediate header 2.

In this modified example, by providing the second outlet 32_1 facing upward in the direction of gravity from the top of the second partition 36, the backflow 105 (see FIG. 4) of liquid refrigerant from the third space 23 to the second space 22 is reduced. This improves the condenser performance and improves the cooling performance of the air conditioning device 200. The improvement is particularly significant during low-load operation where the refrigerant flow velocity is slow.

Figure 15 is an enlarged cross-sectional view in the A-A direction of Figure 12, showing a second modified example of the first intermediate header 1 and the second intermediate header 2 according to embodiment 4. As shown in Figure 15, in the second modified example of embodiment 4, the first outlet 31_1 and the second outlet 32_1 are separated by a first partition 35. That is, the first partition 35 is provided within the range of the height of one opening provided in the pipe 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, and the lower side is the second outlet 32_1.

As long as the first outlet 31_1 and the second outlet 32_1 form different outlets as in this modified example, the first connection pipe 31 and the second connection pipe 32 may be integrated into one pipe. In this modified example, there is no need to raise the liquid refrigerant above the first partition 35 to the upper side before supplying the refrigerant from the first space 21 to the third space 23, so the liquid refrigerant in the first space 21 can be prevented from stagnating. This improves the condenser performance and improves the cooling performance of the air conditioning device 200. The improvement is particularly significant during low-load operation where the refrigerant flow rate is slow.

The embodiments are presented as examples and are not intended to limit the scope of the claims. The embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the embodiments. These embodiments and their variations are included within the scope and spirit of the embodiments.

1 First intermediate header, 2 Second intermediate header, 3_1 First heat transfer tube, 3_2 Second heat transfer tube, 4 Fin, 10 Outdoor heat exchanger, 11 First heat exchanger, 12 Second heat exchanger, 13 Blower, 14 Compressor, 16 Indoor heat exchanger, 17 Throttle device, 18 Refrigerant piping, 21 First space, 22 Second space, 23 Third space, 24 Fourth space, 31 First connecting pipe, 31_1 First outlet, 32 Second connecting pipe, 32_1 Second outlet, 33_1 First inlet, 34_1 Second inlet, 35 First partition, 36 Second partition, 38 Pipe wall, 71 Central axis of first intermediate header 1 in the extension direction, 72 Central axis of second intermediate header 2 in the extension direction, 73 Central axis of connecting pipe, 90 Gravity direction, 100 Liquid refrigerant, 101 Gas refrigerant, 102 liquid-mainly refrigerant, 103 gas-mainly refrigerant, 104 liquid refrigerant stagnation, 105 liquid refrigerant backflow, 111 refrigerant flow from first space to third space, 112 refrigerant flow from second space to third space, 200 air conditioning device, 201 outdoor unit, 202 indoor unit, 203 up-blowing housing, 300 air speed distribution, AF air flow direction.

Claims (12)

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;
a first heat exchanger having a first partition that divides an interior of the first intermediate header into a first space and a second space disposed below the first space;
a second intermediate header disposed in parallel with 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 an interior of the second intermediate header into a third space and a fourth space disposed below the third space,
the first heat transfer tube is a plurality of tubes, and the plurality of first heat transfer tubes include the first heat transfer tube connected to the first space and the first heat transfer tube connected to the second space,
The first intermediate header constituting the first space is provided with a first outlet through which the refrigerant flows out,
The first intermediate header that constitutes the second space is provided with a second outlet through which the refrigerant flows out,
The second intermediate header is connected to the first intermediate header and includes a first inlet through which the refrigerant flows from the first outlet into the third space, and a second inlet through which the refrigerant flows from the second outlet into the third space. 2. The heat exchanger according to claim 1, wherein the first heat transfer tube and the second heat transfer tube are flattened heat transfer tubes whose major axes in cross sections perpendicular to the axial direction of the first heat transfer tube and the second heat transfer tube are aligned along the airflow direction. The second heat transfer tube is connected to the third space,
3. The heat exchanger according to claim 1, wherein a sum of the number of the first heat transfer tubes connected to the first space and the number of the first heat transfer tubes connected to the second space is greater than a number of the second heat transfer tubes. a first connection pipe that connects the first outlet and the first inlet,
4. The heat exchanger according to claim 1, wherein the first connection pipe is provided below an average height of the first heat transfer pipe 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. The heat exchanger according to claim 4 , further comprising a second connection pipe connecting the second outlet and the second inlet. A heat exchanger as described in any one of claims 1 to 7, wherein the first outlet is provided in the pipe wall of the first intermediate header in a range in which the first intermediate header is visible from the central axis of the second intermediate header when viewed in the extension direction of the first intermediate header. The heat exchanger according to any one of claims 1 to 8, wherein the first outlet is provided at a higher position than the first inlet. The refrigerant includes R32, R410A, or at least an olefin-based refrigerant, a refrigerant having a smaller gas density than the R32 refrigerant including propane and DME.
A heat exchanger according to any one of claims 1 to 9. An air conditioner equipped with a heat exchanger according to any one of claims 1 to 10. The air conditioning device includes:
A blower that blows air upward;
an upper blowing housing having an air 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.

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