EP4685419A1

EP4685419A1 - Refrigeration cycle device

Info

Publication number: EP4685419A1
Application number: EP24774967.4A
Authority: EP
Inventors: Hiroaki Takahashi; Toshihiro Takahashi; Naoki OGATA; Ryo Shibata; Junpei OKEDA
Original assignee: Fujitsu General Ltd
Current assignee: Fujitsu General Ltd
Priority date: 2023-03-23
Filing date: 2024-03-21
Publication date: 2026-01-28
Also published as: CN120883014A; WO2024195833A1; JP2024135774A; AU2024237893A1; JP7652205B2

Abstract

There is provided a refrigeration cycle device having: an aluminum refrigerant pipe (22) formed of aluminum or an aluminum alloy, the aluminum refrigerant pipe (22) being connected to an end part (18a) of a tube provided inside a heat exchanger (11) and protruding outside the heat exchanger; a copper refrigerant pipe (23) formed of copper or a copper alloy, the copper refrigerant pipe (23) being connected to a control component, such as a four-way valve or an expansion valve; and a joint part (24) configured to join the aluminum refrigerant pipe and the copper refrigerant pipe to each other, in which the joint part is arranged along the vertical direction perpendicular to the bottom surface (3) of the heat exchanger and the aluminum refrigerant pipe is arranged above the joint part, and the copper refrigerant pipe arranged below the joint part includes a copper straight part (27) extending linearly downward from the joint part with a length equal to or larger than the outer diameter of the copper refrigerant pipe.

Description

Technical Field

The present invention relates to a refrigeration cycle device.

Background Art

An air conditioner as a refrigeration cycle device has an indoor heat exchanger, an outdoor heat exchanger, a compressor, and a control component (four-way valve, expansion valve, or the like) that are connected to one another by refrigerant piping, in which a refrigerant pipe formed of copper or a copper alloy (hereinafter referred to as a copper refrigerant pipe) is used as a refrigerant pipe. In recent years, due to a demand for reduced cost or weight, it has been proposed to replace a tube provided in the indoor heat exchanger or the outdoor heat exchanger and the refrigerant piping protruding outside the indoor heat exchanger or the outdoor heat exchanger with a refrigerant pipe formed of aluminum or an aluminum alloy (hereinafter referred to as an aluminum refrigerant pipe).
As the refrigerant piping connected to the control component, a refrigerant pipe containing copper having higher malleability than that of aluminum has been commonly used due to reliability or manufacturing problems. Therefore, a joint part has been formed which joints the aluminum refrigerant pipe protruding outside the indoor heat exchanger or the outdoor heat exchanger and the copper refrigerant pipe connected to the control component to each other.
In heating operation of the air conditioner, a lowtemperature refrigerant flows into the refrigerant piping of the outdoor heat exchanger to be used as an evaporator, and therefore water vapor contained in the outdoor air condenses, and dew adheres to the copper refrigerant pipe. When dew adheres to the copper refrigerant pipe, water containing copper ions is generated. The flow of the water containing copper ions into the joint part between the aluminum refrigerant pipe and the copper refrigerant pipe poses a risk of the occurrence of electric corrosion in the aluminum refrigerant pipe of the joint part. Further, when the heating operation is performed under a low outdoor air temperature, water generated in the copper refrigerant pipe freezes, and frost or ice sometimes adheres to the copper refrigerant pipe. When the frost or the ice adhering to the copper refrigerant pipe is melted by defrosting operation, the water containing copper ions is generated. Therefore, the flow of the water into the joint part between the aluminum refrigerant pipe and the copper refrigerant pipe poses a risk of the occurrence of the electric corrosion in the aluminum refrigerant pipe of the joint part.
As a technology of preventing the water containing copper ions from flowing into the joint part between the aluminum refrigerant pipe and the copper refrigerant pipe, a technology is known in which at least one of an inverted U-shaped part in which the aluminum refrigerant pipe is formed into an upward convex shape and a U-shaped part in which the copper refrigerant pipe is formed into a downward convex shape is provided near the joint part (e.g., PTL 1).

Citation List

Patent Literature

PTL 1: JP 2014-159952 A

Summary of Invention

Technical Problem

According to the technology of PTL 1, when the joint part between the aluminum refrigerant pipe protruding outside the outdoor heat exchanger and the copper refrigerant pipe is horizontally arranged, the water containing copper ions is prevented from flowing into the joint part. However, a case where the joint part is arranged to be inclined with respect to the horizontal direction, and, for example, the joint part is positioned below the U-shaped part containing the copper refrigerant pipe poses a risk that the water containing copper ions generated in the U-shaped part flows to the side of the joint part, causing the electric corrosion in the aluminum refrigerant pipe of the joint part.
Thus, the present invention has been made to solve such a problem. It is an object of the present invention to provide a refrigeration cycle device capable of preventing the electric corrosion caused by the presence the water containing copper ions even when the joint part between the aluminum refrigerant pipe and the copper refrigerant pipe is arranged to be inclined with respect to the horizontal direction.

Solution to Problem

One aspect of the invention is a refrigeration cycle device having: an aluminum refrigerant pipe formed of aluminum or an aluminum alloy, the aluminum refrigerant pipe being connected to an end part of a tube provided inside a heat exchanger and protruding outside the heat exchanger; a copper refrigerant pipe formed of copper or a copper alloy, the copper refrigerant pipe being connected to a control component, such as a four-way valve or an expansion valve; and a joint part configured to join the aluminum refrigerant pipe and the copper refrigerant pipe to each other, in which the joint part is arranged along the vertical direction perpendicular to the bottom surface of the heat exchanger and the aluminum refrigerant pipe is arranged above the joint part, and the copper refrigerant pipe arranged below the joint part includes a copper straight part extending linearly downward from the joint part with a length equal to or larger than the outer diameter of the copper refrigerant pipe.

Advantageous Effects of Invention

The refrigeration cycle device of the present invention can prevent the electric corrosion caused by the presence of the water containing copper ions in the joint part between the aluminum refrigerant pipe and the copper refrigerant pipe even when the joint part is arranged to be inclined with respect to the horizontal direction.

Brief Description of Drawings

FIG. 1 is a view illustrating the appearance of an outdoor unit constituting a refrigeration cycle device according to the present invention;
FIG. 2 is a view illustrating the internal structure of the outdoor unit;
FIG. 3 is a view illustrating a heat exchanger arranged inside the outdoor unit;
FIG. 4 is a view illustrating the specific arrangement of a first refrigerant pipe containing an aluminum refrigerant pipe connected to a tube of a heat exchanger and a copper refrigerant pipe;
FIG. 5 is a view illustrating the arrangement of the first refrigerant pipe when the heat exchanger is arranged to be inclined;
FIG. 6 is a view illustrating a joint part of a second embodiment between the aluminum refrigerant pipe and the copper refrigerant pipe; and
FIG. 7 is a view illustrating a joint part of a third embodiment between the aluminum refrigerant pipe and the copper refrigerant pipe.

Description of Embodiments

Next, embodiments according to the present invention are described with reference to the drawings. The embodiments described below exemplify devices or methods for embodying the technical idea of the present invention. The technical idea of the present invention does not specify the materials, shapes, structures, arrangement, and the like of constituent components to the materials, shapes, structures, arrangement, and the like described below. The technical idea of the present invention can be variously altered in the technical scope defined by claims.

[Outdoor unit of First embodiment]

FIG. 1 is a view illustrating the appearance of an outdoor unit 1 of an air conditioner that is a type of refrigeration cycle device. FIG. 2 is a view illustrating the internal structure of the outdoor unit 1.
As illustrated in FIG. 1, the outdoor unit 1 has a box-like casing 2. The casing 2 has a base 3 (see FIG. 2) forming the bottom surface of the casing 2, a front panel 4 forming the front surface of the casing 2, a right-side panel 5 and a left-side panel 6 forming the side surfaces of the casing 2, and a top plate 7 forming the upper surface of the casing 2. The front panel 4 is provided with an outlet, and a fan guard 8 is attached to the outlet. The base 3 corresponds to the bottom surface of the present invention.
As illustrated in FIG. 2, the casing 2 houses a compressor 10, a heat exchanger (outdoor heat exchanger) 11, an expansion valve 12, a blowing fan 13, an electrical unit 14, and the like thereinside.
The internal space of the casing 2 is divided by a partition plate 15 into a machine chamber 16 where the compressor 10, the expansion valve 12, the electrical unit 14, and the like are arranged and a heat exchange chamber 17 where the blowing fan 13 and the heat exchanger 11 are arranged.
As illustrated in FIG. 2, the heat exchanger 11 is provided in an L-shape along the side surface on the left side from the back surface of the casing 2 and has a tube 18 formed in a serpentine shape and a plurality of fins 19 formed of thin metal plates. The plurality of fins 19 extends in the vertical direction, arranged at equal intervals in the horizontal direction, and provided in an L-shape. The tube 18 is a refrigerant pipe formed of aluminum or an aluminum alloy, is inserted in a direction orthogonal to the plurality of fins 19 arranged in an L-shape, and arranged to be returned to be aligned in parallel to each other in the vertical direction.
As illustrated in FIG. 3, the tube 18 has one end protruding outward from the lower side of a right-side part of the heat exchanger 11, and the tube 18 has one end 18a (see FIG. 4) to which one end of the first refrigerant pipe 20 is joined. The expansion valve 12 is connected to the other end of the first refrigerant pipe 20. The tube 18 has the other end 18b protruding outward from the upper side of the right-side part of the heat exchanger 11, and, to the other end 18b of the tube 18, one end of a second refrigerant pipe 21 is joined. The compressor 10 is connected to the other end of the second refrigerant pipe 21.
In heating operation of the air conditioner, the heat exchanger 11 is used as an evaporator, and a lowtemperature refrigerant that has been reduced in pressure by the expansion valve 12 flows in the order of the first refrigerant pipe 20, the tube 18 of the heat exchanger 11, the second refrigerant pipe 21, and the compressor 10.
The first refrigerant pipe 20 has an aluminum refrigerant pipe 22 formed of aluminum or an aluminum alloy to be joined to the one end 18a of the tube 18 and a copper refrigerant pipe 23 formed of copper or a copper alloy to be joined to the expansion valve 12.
The aluminum refrigerant pipe 22 and the copper refrigerant pipe 23 are straight pipe members having the outer diameter dimensions identical to each other, and joined to each other at end parts, forming a joint part 24.
The joint part 24, the outer periphery of the end part of the aluminum refrigerant pipe 22, and the outer periphery of the end part of the copper refrigerant pipe 24 are mounted with a cylindrical waterproof coating material 31 formed of an insulating material. The waterproof coating material 31 is a heat-shrinkable tube closely adhering to the joint part 24, and the outer peripheries of end parts of a second straight part 26b and a copper straight part 27.
The straight pipe-shaped aluminum refrigerant pipe 22 is bent to have an aluminum straight part 25 and an aluminum U-shaped part 26 having a U-shape formed continuously from an end part of the aluminum straight part 25. The aluminum U-shaped part 26 has a first straight part 26a bent in a direction orthogonal to the aluminum straight part 25, the second straight part 26b extending in parallel to the first straight part 26a, longer than the first straight part 26a, and formed with the joint part 24 on the end part side, and a semicircular arc part 26c coupling one end of the first straight part 26a and one end of the second straight part 26b to each other.
The straight pipe-shaped copper refrigerant pipe 23 is bent to have the copper straight part 27 formed with the joint part 24 on the end part side and a copper U-shaped part 28 having a U-shape formed continuously from the end part of the copper straight part 27. A length L of the copper straight part 27 is set to a dimension equal to or larger than the outer diameter φ of the copper refrigerant pipe 23.
The aluminum refrigerant pipe 22 is arranged such that the aluminum U-shaped part 26 has an upward convex shape, and the end part of the aluminum straight part 25 is joined to the one end 18a of the tube 18 such that the aluminum straight part 25 extends in parallel to the base 3. Thus, the second straight part 26b of the aluminum U-shaped part 26 is arranged along the vertical direction perpendicular to the base. The joining position of the aluminum straight part 25 and the one end 18a of the tube 18 is referred to as a heat exchanger-side joint part 29. The aluminum U-shaped part 26 arranged to have an upward convex shape corresponds to the inverted U-shaped part of the aluminum refrigerant pipe in the present invention. The length L of the copper straight part 27 corresponds to the length equal to or larger than the outer diameter of the copper refrigerant pipe extending linearly downward from the joint part of the copper straight part in the present invention.
The joint part 24 between the aluminum refrigerant pipe 22 and the copper refrigerant pipe 23 is formed by joining an upper end part of the copper straight part 27 of the copper refrigerant pipe 23 and a lower end part of the second straight part 26b of the aluminum refrigerant pipe 22 to each other by butt-welding. The joint part 24 is arranged along the vertical direction perpendicular to the base 3.
The copper U-shaped part 28 of the copper refrigerant pipe 23 is arranged to have a downward convex shape and the heat exchanger-side joint part 29 between the aluminum straight part 25 and the one end 18a of the tube 18 is arranged at a position above the joint part 24 and the copper U-shaped part 28 of the copper refrigerant pipe 23. The copper U-shaped part 28 arranged to have a downward convex shape corresponds to the U-shaped part of copper refrigerant piping in the present invention. Herein, another copper refrigerant pipe 30 is joined to the other end of the copper U-shaped part 28 by wielding, and this copper refrigerant pipe 30 corresponds to the second copper refrigerant pipe in the present invention and is connected to the expansion valve 12.
The waterproof coating material 31 closely adheres to the outer peripheries of the joint part 24, the lower end part of the second straight part 26b, and the upper end part of the copper straight part 27, thereby ensuring water tightness to the joint part 24 and the copper straight part 27 and preventing the generation of the water containing copper ions in the joint part 24 or the copper straight part 27 close to the aluminum refrigerant pipe 22. Therefore, the waterproof coating material 31 can prevent the water containing copper ions generated in the copper refrigerant pipe 23 from flowing into the aluminum refrigerant pipe 22. More specifically, the waterproof coating material 31 is required be mounted on at least the joint part 24 and the copper straight part 27. The waterproof coating material 31 ensures the water tightness also by using a water repellent coating, butyl rubber, or the like without being limited to the heat-shrinkable tube.
Herein, the joint part between the copper U-shaped part 28 and the copper refrigerant pipe 30 described above may be arranged at a distance such that, when the copper U-shaped part 28 and the copper refrigerant pipe 30 are joined to each other by welding, the flame of a welding burner does not directly touch the waterproof coating material 31 and the aluminum refrigerant pipe 22 and the heat of the welding burner does not deform the shape of the waterproof coating material 31, impairing the covering effect. More specifically, this distance corresponds to the distance where the waterproof coating material and the joint part are not affected by a thermal effect caused by the welding.
Next, the action of the heat exchanger 11 having the first refrigerant pipe 20 is described with reference to FIGS. 4 and 5. FIG. 4 illustrates a state in which the base 3 of the casing 2 is installed on the horizontal installation surface. FIG. 5 illustrates a state in which the base 3 of the casing 2 is installed on an installation surface inclined at θ = 5°, which is the maximum inclination angle at which the heat exchanger 11 can be installed. Hereinafter, FIG. 4 is referred to as the horizontal installation state and FIG. 5 is referred to as the inclined installation state.
When the heating operation of the air conditioner is performed under a low outdoor air temperature, a low temperature refrigerant flows into the first refrigerant pipe 20 of the heat exchanger 11 to be used as an evaporator. Therefore, water vapor contained in the outdoor air condenses, and frost or ice adheres to the copper refrigerant pipe 23. When the frost or the ice adhering to the copper refrigerant pipe 23 is melted by defrosting operation, the water containing copper ions is sometimes generated and accumulates in the copper U-shaped part 28.
The joint part 24 of the first refrigerant pipe 20 is arranged along the vertical direction, whether in the horizontal installation state in FIG. 4 or in the inclined installation state in FIG. 5, the second straight part 26b of the aluminum refrigerant pipe 22 is arranged above the joint part 24, and the copper straight part 27 of the copper refrigerant pipe 23 is arranged below the joint part 24, and therefore the water containing copper ions accumulating in the copper U-shaped part 28 does not flow into the joint part 24.
Further, the length L of the copper straight part 27 is set to a dimension equal to or larger than the outer diameter of the copper straight part 27, and the distance between the copper U-shaped part 28 and the joint part 24 can be ensured to be a distance larger than the size of water droplets generated by condensation. Therefore, even when the frost or the ice generated in the copper U-shaped part 28 grows, the frost or the ice is less likely to reach the joint part 24. Therefore, even when the defrosting operation melts the frost or the ice generated in the copper U-shaped part 28, the water containing copper ions can be prevented from generating in the joint part 24 and reaching the aluminum refrigerant pipe 22.
Further, the aluminum refrigerant pipe 22 is provided with the aluminum straight part 25 extending in parallel to the base 3 at a position above the joint part 24 and the aluminum U-shaped part 26 arranged to have an upward convex shape between the aluminum straight part 25 and the joint part 24, and therefore vibration caused by the compressor can be suppressed from transmitting to the heat exchanger-side joint part 29 via the copper refrigerant pipe 23.
The heat exchanger-side joint part 29 between the aluminum straight part 25 and the one end 18a of the tube 18 is arranged at a position above the joint part 24 and the copper U-shaped part 28 of the copper refrigerant pipe 23. Therefore, even in the inclined installation state illustrated in FIG. 5, the water containing copper ions accumulating in the copper U-shaped part 28 is reliably prevented from flowing into the aluminum straight part 25 and the heat exchanger 11.
The waterproof coating material 31 is mounted on the outer periphery of the joint part 24, so that watertightness is ensured. Therefore, the water containing copper ions is reliably prevented from flowing into the joint part 24.
Thus, even when the heat exchanger 11 is installed on an inclined surface, the joint part 24 of the first refrigerant pipe 20 is arranged along the vertical direction. Therefore, the water containing copper ions does not flow into the joint part 24 between the copper refrigerant pipe 23 (copper straight part 27) and the aluminum refrigerant pipe 22 (second straight part 26b), and the electric corrosion of the aluminum refrigerant pipe 22 (second straight part 26b) can be reliably prevented.
Further, a joint part between the copper U-shaped part 28 and the copper refrigerant pipe 30 is arranged at such a distance that, when the end surfaces are joined to each other by welding, the flame of a welding burner does not directly touch the waterproof coating material 31 and the aluminum refrigerant pipe 22. Therefore, welding work of the copper U-shaped part 28 and the copper refrigerant pipe 30 can be carried out easily and accurately.

[Joint parts of Second and Third embodiments]

Next, FIGS. 6 and 7 illustrate joint parts of second and third embodiments having structures different from that of the joint part 24 of the first embodiment between the aluminum refrigerant pipe 22 (second straight part 26b) and the copper refrigerant pipe 23 (copper straight part 27) illustrated in FIG. 4.
FIG. 6 illustrates the joint part of the second embodiment, in which a joint part 33 is formed by arranging a stainless steel pipe 32 between the upper end part of the copper straight part 27 and the lower end part of the second straight part 26b, joining the upper end part of the copper straight part 27 and one end of the stainless steel pipe 32 to each other by welding, and joining the lower end part of the second straight part 26b and the other end of the stainless steel pipe 32 to each other by welding. The waterproof coating material 31 is mounted on the outer peripheries of the joint part 33, the second straight part 26b, and the copper straight part 27.
In the second embodiment, the joint part 33 between the copper refrigerant pipe 23 (copper straight part 27) and the aluminum refrigerant pipe 22 (second straight part 26b) is arranged along the vertical direction. Therefore, even when the heat exchanger 11 is installed on an inclined surface, the water containing copper ions does not flow into the joint part 33, and the electric corrosion of the aluminum refrigerant pipe 22 (second straight part 26b) can be reliably prevented.
FIG. 7 illustrates a joint part of the second embodiment, in which a joint part 35 is formed by making the upper end part of the copper straight part 27 and the lower end part of the second straight part 26b abut on each other and joining the copper straight part 27 and the second straight part 26b to each other by a fitting member 34 mounted on the outer peripheries of the copper straight part 27 and the second straight part 26b. The waterproof coating material 31 is mounted on the outer peripheries of the joint part 35, the second straight part 26b, and the copper straight part 27.
In the third embodiment, the joint part 35 between the copper refrigerant pipe 23 (copper straight part 27) and the aluminum refrigerant pipe 22 (second straight part 26b) is arranged along the vertical direction. Therefore, even when the heat exchanger 11 is installed on an inclined surface, the water containing copper ions does not flow into the joint part 35, and the electric corrosion of the aluminum refrigerant pipe 22 (second straight part 26b) can be reliably prevented.

Reference Signs List

1:: outdoor unit
2:: casing
3:: base
4:: front panel
5:: right-side panel
6:: left-side panel
7:: top plate
8:: fan guard
10:: compressor
11:: heat exchanger
12:: expansion valve
13:: blowing fan
14:: electrical unit
15:: partition plate
16:: machine chamber
17:: heat exchange chamber
18:: tube
18a:: one end of tube
18b:: other end of tube
19:: fin
20:: first refrigerant pipe
21:: second refrigerant pipe
22:: aluminum refrigerant pipe
23:: copper refrigerant pipe
24:: joint part
25:: aluminum straight part
26:: aluminum U-shaped part
26a:: first straight part
26b:: second straight part
26c:: semicircular arc part
27:: copper straight part
28:: copper U-shaped part
29:: heat exchanger-side joint part
30:: copper refrigerant pipe
31:: waterproof coating material
32:: stainless steel pipe
33:: joint part
34:: fitting member
35:: joint part

Claims

A refrigeration cycle device comprising:
an aluminum refrigerant pipe formed of aluminum or an aluminum alloy, the aluminum refrigerant pipe being connected to an end part of a tube provided inside a heat exchanger and protruding outside the heat exchanger;

a copper refrigerant pipe formed of copper or a copper alloy, the copper refrigerant pipe being connected to a control component, such as a four-way valve or an expansion valve; and

a joint part configured to join the aluminum refrigerant pipe and the copper refrigerant pipe to each other, wherein

the joint part is arranged along a vertical direction perpendicular to a bottom surface of the heat exchanger and the aluminum refrigerant pipe is arranged above the joint part, and

the copper refrigerant pipe arranged below the joint part includes a copper straight part extending linearly downward from the joint part with a length equal to or larger than an outer diameter of the copper refrigerant pipe.
The refrigeration cycle device according to claim 1, wherein the copper straight part includes a U-shaped part formed into a downward convex shape at a lower end.
The refrigeration cycle device according to claim 1 or 2, wherein the aluminum refrigerant pipe includes:
an aluminum straight part extending in parallel to the bottom surface of the heat exchanger at a position above the joint part; and

an inverted U-shaped part provided between the aluminum straight part and the joint part and formed into an upward convex shape.
The refrigeration cycle device according to claim 1 or 2, wherein a waterproof coating material configured to cover the joint part and the copper straight part is provided.
The refrigeration cycle device according to claim 2, wherein
a waterproof coating material covering the joint part and the copper straight part is provided at one end of the copper refrigerant pipe,

another end of the copper refrigerant pipe is joined to a second copper refrigerant pipe by welding, and a distance between a site where the second copper refrigerant pipe and the U-shaped part are joined to each other and the joint part is set to such a distance that the waterproof coating material and the aluminum refrigerant pipe are not affected by a thermal effect caused by the welding.
The refrigeration cycle device according to claim 1 or 2, wherein a heat exchanger-side joint part configured to join the tube and the aluminum refrigerant pipe to each other is arranged at a position above the joint part.