The present invention relates to a stacking-type header, a heat exchanger, and an air-conditioning apparatus.

As a related-art heat exchanger, there is known a heat exchanger including a return header including a tube bonding member with which flat tubes and a member are bonded to each other, a tube fixing member configured to position end portions of the flat tubes, a spacer portion, and a back plate, and having a refrigerant joining space formed in the return header so as to move refrigerant in a row direction (see, for example, Patent Literature 1).

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2013-29243 (paragraph [0033], Fig. 6)

In the heat exchanger disclosed in Patent Literature 1, flows of the refrigerant passing through flow passage holes of the tube (flat tube) are joined to each other in the refrigerant joining space defined in the return header to move in a direction orthogonal to the flow passages of the tube. Then, the refrigerant moving through the refrigerant joining space flows into flow passage holes of an other tube.

However, an inertia force acts on the refrigerant flowing through the refrigerant joining space, and hence the refrigerant unevenly flows into the flow passage holes of the tube from the refrigerant joining space, thereby causing a problem in that the refrigerant cannot be distributed evenly.

When refrigerant in a two-phase gas-liquid state flows into the tube of the heat exchanger, it is desired, on the other hand, that the ratio between gas-phase refrigerant and liquid-phase refrigerant flowing into the plurality of flow passages inside the tube (distribution ratio) be adjustable appropriately.

For example, in a heat exchanger configured to exchange heat between air passing through the heat exchanger and refrigerant flowing inside the tube, a heat load (heat exchange amount) on an air upstream side (an upstream side of air) is larger than that on an air downstream side (a downstream side of air). Therefore, it is desired that the distribution ratio be adjusted so as to increase the latent heat amount of the refrigerant flowing through the flow passages on the air upstream side.

The present invention has been made in view of the problems as described above, and therefore has an object to provide a stacking-type header, which is connected to a plurality of tubes so that a fluid flowing into the stacking-type header from one tube is caused to flow into an other tube, and is capable of reducing unevenness of the fluid flowing into the tube.

Further, the present invention has an object to provide a stacking-type header capable of adjusting a distribution ratio of a fluid flowing into a tube from the stacking-type header.

Still further, the present invention has an object to provide a heat exchanger including the stacking-type header as described above.

Still further, the present invention has an object to provide an air-conditioning apparatus including the heat exchanger as described above.

According to one embodiment of the present invention, there is provided a stacking-type header to be connected to a plurality of tubes to allow a fluid flowing into the stacking-type header from one of the plurality of tubes to flow into an other one of the plurality of tubes, the stacking-type header comprising: a first plate-shaped unit having first openings to which the plurality of tubes are connected; a second plate-shaped unit having second openings, and being stacked on the first plate-shaped unit to form flow passages to allow the second openings to communicate with the first openings; and a third plate-shaped unit stacked on the second plate-shaped unit, wherein the third plate-shaped unit includes bridging flow passages each being configured to allow the flow passage corresponding to the tube on one side out of two tubes among the plurality of tubes to communicate with the flow passage corresponding to the tube on an other side out of the two tubes from among the plurality of tubes, and wherein a flow passage area of each of the flow passages of the second openings is smaller than a flow passage area of a corresponding one of the first openings.

According to one embodiment of the present invention, there is provided a heat exchanger, including: the above-mentioned stacking-type header; and a plurality of tubes connected to the stacking-type header, the plurality of tubes each including a plurality of flow passages formed therein.

According to one embodiment of the present invention, there is provided an air-conditioning apparatus, including the above-mentioned heat exchanger.

According to the one embodiment of the present invention, the unevenness of the fluid flowing into the tube can be reduced in the stacking-type header connected to the plurality of tubes so that the fluid flowing into the stacking-type header from one tube is caused to flow into an other tube.

Further, according to the one embodiment of the present invention, the distribution ratio of the fluid flowing into the tube from the stacking-type header can be adjusted relatively easily.

• [Fig. 1] Fig. 1 is a side view for illustrating a schematic configuration of a heat exchanger 1 according to Embodiment 1.
• [Fig. 2] Fig. 2 is a top view for illustrating the schematic configuration of the heat exchanger 1 according to Embodiment 1.
• [Fig. 3] Fig. 3 is a schematic configuration view for illustrating a cross section of each of a first heat transfer tube 4 and a second heat transfer tube 7 of the heat exchanger 1 according to Embodiment 1.
• [Fig. 4] Fig. 4 is a perspective view for illustrating a stacking-type header 2 of the heat exchanger 1 according to Embodiment 1 under a state in which the stacking-type header 2 is disassembled.
• [Fig. 5] Fig. 5 is a schematic sectional view for illustrating the stacking-type header 2 of the heat exchanger 1 according to Embodiment 1.
• [Fig. 6] Fig. 6 is a schematic sectional view for illustrating a flow of refrigerant in the stacking-type header 2 of the heat exchanger 1 according to Embodiment 1.
• [Fig. 7] Fig. 7 is a sectional view taken along the line I-I of Fig. 6.
• [Fig. 8] Fig. 8 is a sectional view taken along the line II-II of Fig. 6.
• [Fig. 9] Fig. 9 is a sectional view taken along the line III-III of Fig. 6.
• [Fig. 10] Fig. 10 is a schematic sectional view for illustrating a stacking-type header 2 of a heat exchanger 1 according to Embodiment 2.
• [Fig. 11] Fig. 11 is a schematic sectional view for illustrating a flow of refrigerant in the stacking-type header 2 of the heat exchanger 1 according to Embodiment 2.
• [Fig. 12] Fig. 12 is a sectional view taken along the line I-I of Fig. 11.
• [Fig. 13] Fig. 13 is a sectional view taken along the line II-II of Fig. 11.
• [Fig. 14] Fig. 14 is a sectional view taken along the line III-III of Fig. 11.
• [Fig. 15] Fig. 15 is a diagram for illustrating a configuration of an air-conditioning apparatus to which the heat exchanger 1 according to Embodiment 2 is applied.
• [Fig. 16] Fig. 16 is a view for illustrating a liquid amount distribution of the refrigerant flowing into the second heat transfer tube 7 when the heat exchanger 1 according to Embodiment 2 serves as an evaporator.
• [Fig. 17] Fig. 17 is a graph for showing the liquid amount distribution of the refrigerant flowing into the second heat transfer tube 7 when the heat exchanger 1 according to Embodiment 2 serves as the evaporator.
• [Fig. 18] Fig. 18 is a graph for showing temperature changes of air and the refrigerant when the heat exchanger 1 according to Embodiment 2 serves as the evaporator.
• [Fig. 19] Fig. 19 is a view for illustrating a gas amount distribution of the refrigerant flowing into the first heat transfer tube 4 when the heat exchanger 1 according to Embodiment 2 serves as a condenser.
• [Fig. 20] Fig. 20 is a graph for showing the gas amount distribution of the refrigerant flowing into the first heat transfer tube 4 when the heat exchanger 1 according to Embodiment 2 serves as the condenser.
• [Fig. 21] Fig. 21 is a graph for showing temperature changes of the air and the refrigerant when the heat exchanger 1 according to Embodiment 2 serves as the condenser.
• [Fig. 22] Fig. 22 is a view for illustrating a turn-back flow passage of a related-art stacking-type header.

A stacking-type header according to the present invention is described with reference to the drawings.

Note that, in the following, there is described a case where the stacking-type header according to the present invention distributes refrigerant flowing into a flat tube being a heat transfer tube of a heat exchanger, but the stacking-type header according to the present invention may distribute refrigerant flowing into other devices. Further, the configuration, operation, and other matters described below are merely examples, and the description is not intended to limit such configuration, operation, and other matters. Further, in the drawings, the same or similar components are denoted by the same reference symbols, or the reference symbols therefor are omitted. Further, the illustration of details in the structure is appropriately simplified or omitted. Further, overlapping description or similar description is appropriately simplified or omitted.

Now, the configuration of a heat exchanger 1 according to Embodiment 1 is described.

Fig. 1 is a side view for illustrating the schematic configuration of the heat exchanger 1 according to Embodiment 1.

Fig. 2 is a top view for illustrating the schematic configuration of the heat exchanger 1 according to Embodiment 1.

As illustrated in Fig. 1 and Fig. 2, the heat exchanger 1 includes a stacking-type header 2, a plurality of first heat transfer tubes 4, a retaining member 5, a plurality of fins 6, and a plurality of second heat transfer tubes 7.

The stacking-type header 2 includes at least one first inlet flow passage 2A, a plurality of first outlet flow passages 2B, a plurality of second inlet flow passages 2C, a second outlet flow passage 2D, and turn-back flow passages 2E for turning back flows of refrigerant, which pass through the first heat transfer tubes 4, to the second heat transfer tubes 7.

Refrigerant tubes are connected to the first inlet flow passage 2A and the second outlet flow passage 2D of the stacking-type header 2, respectively.

The plurality of first heat transfer tubes 4 are connected between the plurality of first outlet flow passages 2B and the turn-back flow passages 2E of the stacking-type header 2, whereas the plurality of second heat transfer tubes 7 are connected between the turn-back flow passages 2E and the plurality of second inlet flow passages 2C of the stacking-type header 2.

The fin 6 has, for example, a plate-shaped shape. The plurality of fins 6 are stacked at predetermined intervals so that a heat medium (for example, air) flows therebetween. The fin 6 is made of a metal material such as aluminum or copper. The fin 6 is made of, for example, aluminum.

Each of the first heat transfer tube 4 and the second heat transfer tube 7 is, for example, a flat tube subjected to hair-pin bending at an end portion side of the heat exchanger 1 that is opposite to the stacking-type header 2.

Each of the first heat transfer tube 4 and the second heat transfer tube 7 is made of a metal material such as aluminum or copper.

End portions of each of the first heat transfer tube 4 and the second heat transfer tube 7 on the stacking-type header 2 side are retained by the plate-shaped retaining member 5 and connected to the plurality of first outlet flow passages 2B of the stacking-type header 2.

The first heat transfer tubes 4 and the second heat transfer tubes 7 are arranged in a plurality of stages in a stacking direction intersecting with an air flow direction. The first heat transfer tubes 4 and the second heat transfer tubes 7 are arranged in rows in a row direction along the air flow direction.

The plurality of first heat transfer tubes 4 and the plurality of second heat transfer tubes 7 are arranged at intervals secured in a direction of the minor axis of the flat shape (stacking direction) while the major axis of the flat shape is oriented in the air flow direction (row direction). Note that, the first heat transfer tubes 4 are, for example, arrayed in the stacking direction alternately with the second heat transfer tubes 7 in an adjacent row (staggered array). In the example illustrated in Fig. 1 and Fig. 2, two rows including the first heat transfer tubes 4 and the second heat transfer tubes 7 are arranged.

Note that, in Fig. 1, there is illustrated a case where eight first heat transfer tubes 4 and eight second heat transfer tubes 7 are provided, but the present invention is not limited to such a case. For example, two first heat transfer tubes 4 and two second heat transfer tubes 7 may be provided.

Fig. 3 is a schematic configuration view for illustrating a cross section of each of the first heat transfer tube 4 and the second heat transfer tube 7 of the heat exchanger 1 according to Embodiment 1.

As illustrated in Fig. 3, inside each of the first heat transfer tube 4 and the second heat transfer tube 7, at least one partition is provided to form a plurality of flow passages 30.

Note that, each of the first heat transfer tube 4 and the second heat transfer tube 7 corresponds to a "tube" of the present invention.

Note that, in Embodiment 1, there is described a case where the flat tube is used, but the present invention is not limited thereto, and a tube having an arbitrary shape, such as a circular tube or a rectangular tube, may be used instead.

The flow of the refrigerant in the heat exchanger 1 according to the embodiment of the present invention is described.

The refrigerant flowing through the refrigerant tube passes through the first inlet flow passage 2A to flow into the stacking-type header 2 to be distributed, and then passes through the plurality of first outlet flow passages 2B to flow out toward the plurality of first heat transfer tubes 4.

The refrigerant passing through the plurality of first heat transfer tubes 4 flows into the plurality of turn-back flow passages 2E of the stacking-type header 2 to be turned back, and flows out therefrom toward the plurality of second heat transfer tubes 7. The flows of the refrigerant passing through the plurality of first heat transfer tubes 4 pass through the second inlet flow passages 2C to flow into the stacking-type header 2 again to be joined, and the joined refrigerant passes through the second outlet flow passage 2D to flow out therefrom toward the refrigerant tube.

In the plurality of first heat transfer tubes 4 and the plurality of second heat transfer tubes 7, the refrigerant exchanges heat with, for example, air supplied by a fan. The refrigerant may reversely flow.

The configuration of the stacking-type header 2 of the heat exchanger 1 according to Embodiment 1 is described.

Fig. 4 is a perspective view for illustrating the stacking-type header 2 of the heat exchanger 1 according to Embodiment 1 under a state in which the stacking-type header 2 is disassembled.

As illustrated in Fig. 4, the stacking-type header 2 includes a first plate-shaped unit 11, a second plate-shaped unit 12, a third plate-shaped unit 13, a fourth plate-shaped unit 14, and a fifth plate-shaped unit 15.

The first plate-shaped unit 11 includes the retaining member 5, a cladding member 26_1, and a first plate-shaped member 21.

The second plate-shaped unit 12 includes a cladding member 26_2.

The third plate-shaped unit 13 includes a third plate-shaped member 23 and a cladding member 26_3.

The fourth plate-shaped unit 14 includes a plurality of fourth plate-shaped members 24_1 to 24_3 and a plurality of cladding members 26_4 and 26_5.

The fifth plate-shaped unit 15 includes a fifth plate-shaped member 25 and a cladding member 26_6.

A brazing material is applied to one or both surfaces of each of the cladding members 26_1 to 26_6.

The first plate-shaped member 21 is stacked on the retaining member 5 through intermediation of the cladding member 26_1.

The third plate-shaped member 23 is stacked on the first plate-shaped member 21 through intermediation of the cladding member 26_2.

The plurality of fourth plate-shaped members 24_1 to 24_3 are stacked on the third plate-shaped member 23 through intermediation of the cladding members 26_3 to 26_5, respectively.

The fifth plate-shaped member 25 is stacked on the fourth plate-shaped member 24_3 through intermediation of the cladding member 26_6.

For example, each of the first plate-shaped member 21, the third plate-shaped member 23, the plurality of fourth plate-shaped members 24_1 to 24_3, and the fifth plate-shaped member 25 has a thickness of from about 1 mm to about 10 mm, and is made of aluminum.

Note that, in some cases, the fourth plate-shaped members 24_1 to 24_3 are collectively referred to as the fourth plate-shaped member 24. Further, in some cases, the cladding members 26_1 to 26_6 are collectively referred to as the cladding member 26.

The plurality of first outlet flow passages 2B of Fig. 1 are formed by flow passages 21 B formed in the first plate-shaped member 21 and flow passages 26B formed in the cladding member 26_1. Each of the flow passages 21 B and the flow passages 26B is a through hole having an inner peripheral surface shaped conforming to an outer peripheral surface of the first heat transfer tube 4.

The end portions of the first heat transfer tubes 4 are joined to the retaining member 5 by brazing to be retained. When the retaining member 5, the cladding member 26_1 and the first plate-shaped member 21 are joined to each other, the end portions of the first heat transfer tubes 4 and the first outlet flow passages 2B are connected to each other.

Note that, the first outlet flow passages 2B and the first heat transfer tubes 4 may be joined to each other without providing the retaining member 5. In such a case, the component cost and the like are reduced.

The plurality of turn-back flow passages 2E of Fig. 1 are formed by flow passages 21E_1 and 21E_2 formed in the first plate-shaped member 21, flow passages 26E_1 and 26E_2 formed in the cladding member 26_2, flow passages 23E formed in the third plate-shaped member 23, and a side surface of the cladding member 26_3.

The end portions of the first heat transfer tubes 4 and the second heat transfer tubes 7 to be connected to the turn-back flow passages 2E are joined to the retaining member 5 by brazing to be retained. When the first heat transfer tubes 4 and the second heat transfer tubes 7 are joined to the retaining member 5, the end portions of the first heat transfer tubes 4 and the second heat transfer tubes 7 are connected to the turn-back flow passages 2E.

Fig. 5 is a schematic sectional view for illustrating the stacking-type header 2 of the heat exchanger 1 according to Embodiment 1. Note that, in Fig. 5, a cross section of a principal part of the stacking-type header 2 is illustrated in an enlarged manner.

As illustrated in Fig. 5, the cladding member 26_2 is stacked on the first plate-shaped member 21, and the flow passages 26E_1 and 26E_2 of the cladding member 26_2 and the flow passages 21E_1 and 21E_2 of the first plate-shaped member 21 are communicated with each other, respectively. The end portions of the first heat transfer tube 4 and the second heat transfer tube 7 are arranged at a distance from the cladding member 26_2, and the flow passages 21E_1 and 21E_2 of the first plate-shaped member 21 define open spaces.

The flow passage 23E formed in the third plate-shaped member 23 is defined by a single opening having a size larger than the two flow passages 26E_1 and 26E_2 formed in the cladding member 26_2. The cladding member 26_3 does not have an opening at a part facing the flow passage 23E. The third plate-shaped member 23 and the cladding member 26_3 are stacked on the cladding member 26_2 to form a lateral bridging flow passage configured to communicate the two flow passages 26E_1 and 26E_2 formed in the cladding member 26_2.

The flow passage area (opening sectional area) of the flow passage 26E_1 formed in the cladding member 26_2 is set smaller than the flow passage area of the flow passage 21 E_1 formed in the first plate-shaped member 21. Further, the flow passage area (opening sectional area) of the flow passage 26E_2 formed in the cladding member 26_2 is smaller than the flow passage area of the flow passage 21E_2 formed in the first plate-shaped member 21.

In addition, the flow passage area of the flow passage 26E_1 formed in the cladding member 26_2 is smaller than the flow passage area of the first heat transfer tube 4. Further, the flow passage area of the flow passage 26E_2 formed in the cladding member 26_2 is set smaller than the flow passage area of the second heat transfer tube 7.

A flow passage cross section V1 of the flow passage 26E_1 formed in the cladding member 26_2 is orthogonal to a center axis C1 of the first heat transfer tube 4. That is, the flow passage cross section V1 of the flow passage 26E_1 is in parallel to a flow passage cross section of the first heat transfer tube 4.

In addition, a flow passage cross section V2 of the flow passage 26E_2 formed in the cladding member 26_2 is orthogonal to a center axis C2 of the first heat transfer tube 4. That is, the flow passage cross section V2 of the flow passage 26E_2 is set in parallel to a flow passage cross section of the second heat transfer tube 7.

Each of the flow passages 26E_1 and 26E_2 formed in the cladding member 26_2 has, for example, a circular shape.

Note that, the shape of each of the flow passages 26E_1 and 26E_2 is not limited to the circular shape, but may be any shape. For example, each of the flow passages 26E_1 and 26E_2 may have a flat shape in which the major axis direction thereof coincides with those of the first heat transfer tube 4 and the second heat transfer tube 7. In this case, the width of each of the flow passages 26E_1 and 26E_2 in the major axis direction is smaller than the width of each of the first heat transfer tube 4 and the second heat transfer tube 7 in the major axis direction.

The shape of the flow passage 21E_1 formed in the first plate-shaped member 21 may be any shape as long as the shape encloses a contour of the first heat transfer tube 4 in sectional view. In addition, the shape of the flow passage 21E_2 may be any shape as long as the shape encloses a contour of the second heat transfer tube 7 in sectional view.

For example, each of the flow passages 21 E_1 and 21E_2 is formed into a flat shape, and at least one of the width in the major axis direction or the width in the minor axis direction is set larger than those of the first heat transfer tube 4 and the second heat transfer tube 7.

Note that, the first plate-shaped member 21, the cladding member 26_1, and the retaining member 5 correspond to a "first plate-shaped unit" of the present invention.

Further, the cladding member 26_2 corresponds to a "second plate-shaped unit" of the present invention.

Still further, the third plate-shaped member 23 and the cladding member 26_3 correspond to a "third plate-shaped unit" of the present invention.

Still further, the flow passages 21 E_1 and 21E_2 formed in the first plate-shaped member 21 correspond to a "first opening" of the present invention.

Still further, the flow passages 26E_1 and 26E_2 formed in the cladding member 26_2 corresponds to a "second opening" of the present invention.

Still further, the flow passage 23E formed in the third plate-shaped member 23 corresponds to a "bridging flow passage" of the present invention.

Reference is made to Fig. 4 again.

A branching flow passage is formed by flow passages 24A formed in the fourth plate-shaped members 24. The flow passage 24A is a linear through groove. The branching flow passage has a structure to branch the refrigerant flowing thereinto from the first inlet flow passage 2A into two flows. The structure is multiply provided. Thereby, the refrigerant is distributed to the plurality of first outlet flow passages 2B.

In addition, a joining flow passage is formed by flow passages 24C formed in the fourth plate-shaped members 24. The flow passage 24C is a rectangular through groove. The joining flow passage is configured to join the flows of the refrigerant flowing thereinto from the second inlet flow passages 2C, to thereby cause the refrigerant to flow out toward the second outlet flow passage 2D.

The first inlet flow passage 2A of Fig. 1 is formed by a flow passage 25A formed in the fifth plate-shaped member 25 and a flow passage 25A formed in the cladding member 26_6. The first inlet flow passage 2A is, for example, a circular through hole.

In addition, the second outlet flow passage 2D of Fig. 1 is formed by a flow passage 25D formed in the fifth plate-shaped member 25 and the flow passage 25D formed in the cladding member 26_6. The second outlet flow passage 2D is, for example, a circular through hole.

Now, the flow of the refrigerant in the stacking-type header 2 of the heat exchanger 1 according to the embodiment of the present invention is described.

The refrigerant flowing into the plurality of first heat transfer tubes 4 from the stacking-type header 2 flows through the first heat transfer tubes 4, and is then turned back at the end portion side of the heat exchanger 1 to flow into the stacking-type header 2 again from the turn-back flow passages 2E. The refrigerant flowing into the turn-back flow passages 2E moves toward the second heat transfer tube 7 side of the turn-back flow passages 2E to flow out therefrom toward the plurality of second heat transfer tubes 7.

The refrigerant flowing into the plurality of second heat transfer tubes 7 from the stacking-type header 2 flows through the second heat transfer tubes 7, and is then turned back at the end portion side of the heat exchanger 1 to flow into the stacking-type header 2 again from the second inlet flow passages 2C. Then, the refrigerant passes through the second outlet flow passage 2D to flow out therefrom toward the refrigerant tube.

In the plurality of first heat transfer tubes 4 and the plurality of second heat transfer tubes 7, the refrigerant exchanges heat with, for example, air supplied by the fan. The refrigerant may reversely flow.

Next, the flow of the refrigerant in the turn-back flow passage 2E of the heat exchanger 1 according to Embodiment 1 is described.

Fig. 6 is a schematic sectional view for illustrating the flow of the refrigerant in the stacking-type header 2 of the heat exchanger 1 according to Embodiment 1. Note that, in Fig. 6, the cross section of the principal part of the stacking-type header 2 is illustrated in an enlarged manner.

Fig. 7 is a sectional view taken along the line I-I of Fig. 6. Fig. 8 is a sectional view taken along the line II-II of Fig. 6. Fig. 9 is a sectional view taken along the line III-III of Fig. 6.

Note that, the arrows illustrated in Fig. 7 to Fig. 9 indicate refrigerant flow directions.

As an example, there is described a case where the refrigerant flows into the stacking-type header 2 from the first heat transfer tube 4, and flows out from the stacking-type header 2 toward the second heat transfer tube 7.

The refrigerant flowing through the first heat transfer tube 4 flows into the flow passage 21E_1 of the first plate-shaped member 21 from the end portion of the first heat transfer tube 4. The refrigerant flowing through the open space of the flow passage 21E_1 is contracted by the flow passage 26E_1 of the cladding member 26_2 to flow out therefrom toward the flow passage 23E formed in the third plate-shaped member 23.

The refrigerant flowing through the flow passage 23E moves toward the second heat transfer tube 7 side, and is contracted by the flow passage 26E_2 of the cladding member 26_2 to flow into the flow passage 21E_2 of the first plate-shaped member 21.

At this time, the refrigerant flowing out from the flow passage 26E_2 of the cladding member 26_2 toward the flow passage 21E_2 of the first plate-shaped member 21 flows through the open space of the flow passage 21E_2 while being expanded therein, and hence the refrigerant is evenly distributed to the plurality of flow passages 30 of the second heat transfer tube 7.

Note that, the refrigerant flow direction is not limited to that described above, but the refrigerant may be caused to flow in a reverse direction.

Fig. 22 is a view for illustrating a turn-back flow passage of a related-art stacking-type header.

The flow passages 21 E_1 and 21E_2 of the first plate-shaped member 21 and the flow passages 26E_1 and 26E_2 of the cladding member 26_2 are not formed in a turn-back flow passage 2E illustrated in Fig. 22.

When the flow passages 26E_1 and 26E_2 of the cladding member 26_2 are not formed as described above, more liquid unevenly flows toward a wall surface in the flow direction due to an inertia force. As a result, the refrigerant to be caused to flow into the plurality of flow passages 30 formed in each of the first heat transfer tube 4 and the second heat transfer tube 7 unevenly flows in the flow direction so that the refrigerant cannot be distributed evenly.

In the stacking-type header 2 of the heat exchanger 1 according to Embodiment 1, on the other hand, the flow passages 21E_1 and 21E_2 of the first plate-shaped member 21 and the flow passages 26E_1 and 26E_2 of the cladding member 26_2 are formed, and the flow passage area (opening sectional area) of each of the flow passages 26E_1 and 26E_2 is smaller than the flow passage area of each of the flow passages 21E_1 and 21E_2.

Therefore, the unevenness of the refrigerant flowing into each of the first heat transfer tube 4 and the second heat transfer tube 7 from the stacking-type header 2 can be suppressed.

Further, for example, when refrigerant in a two-phase gas-liquid flow state flows into the turn-back flow passage 2E, unevenness of liquid-phase refrigerant in each of the flow passages 21E_1 and 21E_2 of the first plate-shaped member 21 can be suppressed, thereby being capable of suppressing unevenness of the distribution ratio in the plurality of flow passages 30 formed in each of the first heat transfer tube 4 and the second heat transfer tube 7.

Further, the flow passage cross section V1 of the flow passage 26E_1 formed in the cladding member 26_2 is orthogonal to the center axis C1 of the first heat transfer tube 4. In addition, the flow passage cross section V2 of the flow passage 26E_2 formed in the cladding member 26_2 is orthogonal to the center axis C2 of the first heat transfer tube 4.

Therefore, when the refrigerant flows into each of the flow passages 26E_1 and 26E_2, the refrigerant flow direction is changed by 90 degrees, thereby increasing the effect of suppressing the unevenness of the liquid-phase refrigerant that may be caused by the inertia force.

Now, a stacking-type header 2 of a heat exchanger 1 according to Embodiment 2 is described focusing on differences from Embodiment 1.

Note that, the same components as those of Embodiment 1 are denoted by the same reference symbols.

Fig. 10 is a schematic sectional view for illustrating the stacking-type header 2 of the heat exchanger 1 according to Embodiment 2. Note that, in Fig. 10, a cross section of a main part of the stacking-type header 2 is illustrated in an enlarged manner.

As illustrated in Fig. 10, in the stacking-type header 2 according to Embodiment 2, a center axis of the flow passage 21 E_1 of the first plate-shaped member 21 and a center axis of the flow passage 26E_1 of the cladding member 26_2 are offset from each other. In addition, a center axis of the flow passage 21E_2 of the first plate-shaped member 21 and a center axis of the flow passage 26E_2 of the cladding member 26_2 are offset from each other.

Specifically, the center axis of the flow passage 26E_1 corresponding to the first heat transfer tube 4 is offset from the center axis of the flow passage 21E_1 toward the second heat transfer tube 7 side, whereas the center axis of the flow passage 26E_2 corresponding to the second heat transfer tube 7 is offset from the center axis of the flow passage 21E_2 toward the first heat transfer tube 4 side.

An offset amount Z of the center axes satisfies a relationship of 0<Z<W3/2, where W3 represents an outer diameter of each of the first heat transfer tube 4 and the second heat transfer tube 7 in the major axis direction.

Further, the center axes are offset so that a distance between the center axis of the flow passage 26E_2 corresponding to the first heat transfer tube 4 and the center axis of the first heat transfer tube 4 is shorter than a distance between the center axis of the second heat transfer tube 7 and the center axis of the flow passage 26E_1 corresponding to the first heat transfer tube 4.

In addition, the center axes are offset so that a distance between the center axis of the flow passage 26E_2 corresponding to the second heat transfer tube 7 and the center axis of the second heat transfer tube 7 is shorter than a distance between the center axis of the first heat transfer tube 4 and the center axis of the flow passage 26E_1 corresponding to the second heat transfer tube 7.

Next, the flow of the refrigerant in the turn-back flow passage 2E of the heat exchanger 1 according to Embodiment 2 is described.

Fig. 11 is a schematic sectional view for illustrating the flow of the refrigerant in the stacking-type header 2 of the heat exchanger 1 according to Embodiment 2. Note that, in Fig. 11, the cross section of the main part of the stacking-type header 2 is illustrated in an enlarged manner.

Fig. 12 is a sectional view taken along the line I-I of Fig. 11. Fig. 13 is a sectional view taken along the line II-II of Fig. 11. Fig. 14 is a sectional view taken along the line III-III of Fig. 11.

Note that, the arrows illustrated in Fig. 11 to Fig. 14 indicate refrigerant flow directions.

As an example, there is described a case where the refrigerant in a two-phase gas-liquid state flows into the stacking-type header 2 from the first heat transfer tube 4, and flows out from the stacking-type header 2 toward the second heat transfer tube 7.

The refrigerant flowing through the first heat transfer tube 4 flows into the flow passage 21E_1 of the first plate-shaped member 21 from the end portion of the first heat transfer tube 4. The refrigerant flowing through the open space of the flow passage 21E_1 is contracted by the flow passage 26E_1 offset toward the second heat transfer tube 7 side to flow out therefrom toward the flow passage 23E formed in the third plate-shaped member 23.

The refrigerant in the two-phase gas-liquid state passing through the flow passage 23E is affected by the inertia force so that refrigerant having high density flows on the outer side and refrigerant having low density flows on the inner side.

The refrigerant flowing through the flow passage 23E moves toward the second heat transfer tube 7 side, and is contracted by the flow passage 26E_2 of the cladding member 26_2 to flow into the flow passage 21E_2 from the flow passage 26E_2 offset toward the first heat transfer tube 4 side.

At this time, the liquid refrigerant flowing out from the flow passage 26E_2 of the cladding member 26_2 toward the flow passage 21E_2 of the first plate-shaped member 21 flows more through the first heat transfer tube 4 side of the open space of the flow passage 21E_2 to which the end portion of the second heat transfer tube 7 is connected. Therefore, the liquid refrigerant flowing into the plurality of flow passages 30 inside the second heat transfer tube 7 from the flow passage 21E_2 of the first plate-shaped member 21 flows more into the flow passages on the first heat transfer tube 4 side.

That is, the ratio between the gas-phase refrigerant and the liquid-phase refrigerant flowing into the plurality of flow passages 30 inside the second heat transfer tube 7 (distribution ratio) can be appropriately adjusted through adjustment of the offset amount Z.

Note that, the refrigerant flow direction is not limited to that described above, but the refrigerant may be caused to flow in a reverse direction. When the refrigerant is caused to flow in the reverse direction to that described above, the ratio between the gas-phase refrigerant and the liquid-phase refrigerant flowing into the plurality of flow passages 30 inside the first heat transfer tube 4 (distribution ratio) can be appropriately adjusted through the adjustment of the offset amount Z.

Now, an example of a usage mode of the heat exchanger 1 according to Embodiment 2 is described.

Note that, in the following, there is described a case where the heat exchanger 1 according to Embodiment 2 is used for an air-conditioning apparatus, but the present invention is not limited to such a case, and for example, the heat exchanger 1 according to Embodiment 2 may be used for other refrigeration cycle apparatus including a refrigerant circuit. Further, there is described a case where the air-conditioning apparatus switches between a cooling operation and a heating operation, but the present invention is not limited to such a case, and the air-conditioning apparatus may perform only the cooling operation or the heating operation.

Fig. 15 is a diagram for illustrating the configuration of the air-conditioning apparatus to which the heat exchanger 1 according to Embodiment 2 is applied. Note that, in Fig. 15, the flow of the refrigerant during the cooling operation is indicated by the solid arrow, while the flow of the refrigerant during the heating operation is indicated by the dotted arrow.

As illustrated in Fig. 15, the air-conditioning apparatus includes a compressor 71, a four-way valve 72, an outdoor heat exchanger (heat source-side heat exchanger) 73, an expansion device 74, an indoor heat exchanger (load-side heat exchanger) 75, an outdoor fan (heat source-side fan) 76, and an indoor fan (load-side fan) 77. The compressor 71, the four-way valve 72, the outdoor heat exchanger 73, the expansion device 74, and the indoor heat exchanger 75 are connected by refrigerant tubes to form a refrigerant circuit. The flow passage of the four-way valve 72 is switched to switch between the cooling operation and the heating operation.

The flow of the refrigerant during the cooling operation is described.

The refrigerant in a high-pressure and high-temperature gas state discharged from the compressor 71 passes through the four-way valve 72 to flow into the outdoor heat exchanger 73, and is condensed through heat exchange with air supplied by the outdoor fan 76. The condensed refrigerant is brought into a high-pressure liquid state to flow out from the outdoor heat exchanger 73. The refrigerant is then brought into a low-pressure two-phase gas-liquid state by the expansion device 74. The refrigerant in the low-pressure two-phase gas-liquid state flows into the indoor heat exchanger 75, and is evaporated through heat exchange with air supplied by the indoor fan 77, to thereby cool the inside of a room. The evaporated refrigerant is brought into a low-pressure gas state to flow out from the indoor heat exchanger 75. The refrigerant then passes through the four-way valve 72 to be sucked into the compressor 71.

The flow of the refrigerant during the heating operation is described.

The refrigerant in a high-pressure and high-temperature gas state discharged from the compressor 71 passes through the four-way valve 72 to flow into the indoor heat exchanger 75, and is condensed through heat exchange with air supplied by the indoor fan 77, to thereby heat the inside of the room. The condensed refrigerant is brought into a high-pressure liquid state to flow out from the indoor heat exchanger 75. The refrigerant then turns into refrigerant in a low-pressure two-phase gas-liquid state by the expansion device 74. The refrigerant in the low-pressure two-phase gas-liquid state flows into the outdoor heat exchanger 73, and is evaporated through heat exchange with air supplied by the outdoor fan 76. The evaporated refrigerant is brought into a low-pressure gas state to flow out from the outdoor heat exchanger 73. The refrigerant then passes through the four-way valve 72 to be sucked into the compressor 71.

The heat exchanger 1 is used for at least one of the outdoor heat exchanger 73 or the indoor heat exchanger 75. When the heat exchanger 1 serves as the evaporator, the heat exchanger 1 is connected so that the refrigerant flows in from the first inlet flow passage 2A of the stacking-type header 2 and the refrigerant flows out from the second outlet flow passage 2D. In other words, when the heat exchanger 1 serves as the evaporator, the refrigerant in the two-phase gas-liquid state passes through the refrigerant tube to flow into the stacking-type header 2. Further, when the heat exchanger 1 serves as the condenser, the refrigerant reversely flows through the stacking-type header 2.

Further, when the heat exchanger 1 serves as the evaporator, the refrigerant passes through the first heat transfer tube 4 arranged in a row on an air upstream side, and then passes through the turn-back flow passage 2E of the stacking-type header 2 to flow into the second heat transfer tube 7 arranged in a row on an air downstream side.

In addition, when the heat exchanger 1 serves as the condenser, the refrigerant passes through the second heat transfer tube 7 arranged in the row on the air downstream side, and then passes through the turn-back flow passage 2E of the stacking-type header 2 to flow into the first heat transfer tube 4 arranged in the row on the air upstream side.

Now, actions of the heat exchanger 1 according to Embodiment 2 are described.

Fig. 16 and Fig. 17 are diagrams for illustrating a liquid amount distribution of the refrigerant flowing into the second heat transfer tube 7 when the heat exchanger 1 according to Embodiment 2 of the present invention serves as the evaporator.

Fig. 18 is a graph for showing temperature changes of air and the refrigerant when the heat exchanger 1 according to Embodiment 2 serves as the evaporator.

As illustrated in Fig. 16, when the heat exchanger 1 serves as the evaporator, the refrigerant flows in a direction along that of the air flow generated through the drive of the outdoor fan 76. Specifically, the refrigerant flows into the flow passage 26E_1 from the first heat transfer tube 4, and then flows into the flow passage 26E_2 from the flow passage 23E in the two-phase gas-liquid state. The refrigerant in the two-phase gas-liquid state passing through the flow passage 23E is affected by the inertia force so that refrigerant having high density flows on the outer side and refrigerant having low density flows on the inner side.

Therefore, as shown in Fig. 17, when the offset amount Z of the flow passage 26E_2 is Z=0, the liquid refrigerant flowing into the flow passage 26E_2 flows more into a point L side of the second heat transfer tube 7 than into a point S side thereof.

In contrast, in the heat exchanger 1, the offset amount Z of the flow passage 26E_2 is Z>0, and hence the liquid refrigerant flowing into the flow passage 26E_2 flows more into the point S side of the second heat transfer tube 7.

Further, as shown in Fig. 18, when the heat exchanger 1 serves as the evaporator, a temperature difference between the air and the refrigerant passing through the heat exchanger 1 is more significant on the air upstream side. Specifically, the heat load (heat exchange amount) is larger on the air upstream side of the air flow generated through the drive of the outdoor fan 76. Therefore, the refrigerant is distributed to the flow passages 30 of the second heat transfer tube 7 so that the liquid refrigerant flows more into the point S side of the second heat transfer tube 7, that is, into the flow passages on the air upstream side. Thus, the evaporation of the liquid refrigerant is promoted to enhance the heat exchange efficiency.

Fig. 19 is a view for illustrating a gas amount distribution of the refrigerant flowing into the first heat transfer tube 4 when the heat exchanger 1 according to Embodiment 2 serves as the condenser.

Fig. 20 is a graph for showing the gas amount distribution of the refrigerant flowing into the first heat transfer tube 4 when the heat exchanger 1 according to Embodiment 2 serves as the condenser.

Fig. 21 is a graph for showing temperature changes of the air and the refrigerant when the heat exchanger 1 according to Embodiment 2 serves as the condenser.

As illustrated in Fig. 19, when the heat exchanger 1 serves as the condenser, the refrigerant flows in a reverse direction to that of the air flow generated through the drive of the outdoor fan 76. Specifically, the refrigerant flows into the flow passage 26E_2 from the second heat transfer tube 7, and then flows into the flow passage 26E_1 from the flow passage 23E in the two-phase gas-liquid state. The refrigerant in the two-phase gas-liquid state passing through the flow passage 23E is affected by the inertia force so that refrigerant having high density flows on the outer side and refrigerant having low density flows on the inner side.

Therefore, as shown in Fig. 20, when the offset amount Z of the flow passage 26E_1 is Z=0, the gas refrigerant flowing into the flow passage 26E_1 flows more into a point L side of the first heat transfer tube 4 than into a point S side thereof.

In contrast, in the heat exchanger 1, the offset amount Z of the flow passage 26E_1 is Z>0, and hence the gas refrigerant flowing into the flow passage 26E_1 flows more into the point S side of the first heat transfer tube 4.

Further, as shown in Fig. 21, when the heat exchanger 1 serves as the condenser, the temperature difference between the air and the refrigerant passing through the heat exchanger 1 is more significant on the air upstream side. Specifically, the heat load (heat exchange amount) is larger on the air upstream side of the air flow generated through the drive of the outdoor fan 76. Therefore, the refrigerant is distributed to the plurality of flow passages 30 of the first heat transfer tube 4 so that the gas refrigerant flows more into the point 2 side of the first heat transfer tube 4, that is, into the flow passages on the air upstream side. Thus, the condensation of the gas refrigerant is promoted to enhance the heat exchange efficiency.

Note that, in Embodiment 2, there is described a case where each of the flow passages 26E_1 and 26E_2 is offset in view of the relationship between the flow direction of the refrigerant in the two-phase gas-liquid state and the air flow direction, but the present invention is not limited thereto. The distribution ratio of the fluid flowing into each of the first heat transfer tube 4 and the second heat transfer tube 7 from the stacking-type header 2 can be appropriately adjusted by arbitrarily setting the offset amount and the offset direction.

As described above, the distribution ratio of the refrigerant can be adjusted relatively easily, and hence the stacking-type header 2 can be used under a variety of situations, environments, or other conditions.

Further, the turn-back flow passage 2E is formed by the flow passages 21E_1 and 21E_2 formed in the first plate-shaped member 21, the first outlet flow passages 2B formed in the cladding member 26_2, and the flow passage 23E formed in the third plate-shaped member 23. Thus, the above-mentioned adjustment of the offset amount and the offset direction can be realized without complicating the structure, thereby reducing the component cost, the number of manufacturing steps, and the like.

• 1 heat exchanger2 stacking-type header 2A first inlet flow passage
• 2B first outlet flow passage 2C second inlet flow passage 2D second outlet flow passage 2E turn-back flow passage 4 first heat transfer tube5 retaining member 6 fin 7 second heat transfer tube 11 first plate-shaped unit
• 12 second plate-shaped unit 13 third plate-shaped unit 14 fourth plate-shaped unit 15 fifth plate-shaped unit 21 first plate-shaped member
• 21 B flow passage 21E_1 flow passage 21E_2 flow passage 23 third plate-shaped member 23E flow passage 24 fourth plate-shaped member 24A flow passage 24B flow passage 24_1 fourth plate-shaped member 24_2 fourth plate-shaped member 24_3 fourth plate-shaped member 25 fifth plate-shaped member 25A flow passage 25D flow passage 26 cladding member 26B flow passage 26E_1 flow passage 26E_2 flow passage 26_1 cladding member 26_2 cladding member 26_3 cladding member 26_4 cladding member 26_5 cladding member 26_6 cladding member 30 flow passage 71 compressor 72 four-way valve 73 outdoor heat exchanger 74 expansion device 75 indoor heat exchanger 76 outdoor fan 77 indoor fan