INDOOR UNIT AND AIR CONDITIONER

Abstract

An indoor unit includes a casing, a heat exchanger accommodated in the casing, and connection pipe, connected to the heat exchanger, through which a refrigerant flows. The connection pipe includes a first refrigerant pipe made of a first metal and a second refrigerant pipe made of a second metal higher in potential than the first metal. One end of the first refrigerant pipe is connected to the heat exchanger, and the other end of the first refrigerant pipe is connected to one end of the second refrigerant pipe in the casing.

Description

BACKGROUND

TECHNICAL FIELD

The present disclosure relates to an indoor unit and an air conditioner.

DISCUSSION OF THE BACKGROUND

Examples of a known indoor unit include an indoor unit in which a connection portion between a first refrigerant pipe formed of aluminum or an aluminum alloy and a second refrigerant pipe formed of copper or a copper alloy is disposed at a falling portion of the first refrigerant pipe, and the first refrigerant pipe is entirely covered with a heat insulating material for corrosion prevention (see, for example, JP 2013-155892 A).

SUMMARY

In one aspect, an indoor unit of the present disclosure includes:

• • a casing;
  • a heat exchanger accommodated in the casing; and
  • a connection pipe that is connected to the heat exchanger and through which a refrigerant flows,
  • in which
  • the connection pipe includes:
  • a first refrigerant pipe having one end connected to the heat exchanger, the first refrigerant pipe being formed of a first metal; and
  • a second refrigerant pipe formed of a second metal having a smaller ionization tendency than an ionization tendency of the first metal of the first refrigerant pipe, and
  • the second refrigerant pipe has one end connected to the other end of the first refrigerant pipe in the casing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a refrigerant circuit diagram of an air conditioner including an indoor unit of a first example of the present disclosure.

FIG. 2 is a perspective view of an indoor unit of the air conditioner of the first example.

FIG. 3 is a front view of the indoor unit of the air conditioner of the first example.

FIG. 4 is a rear perspective view of the indoor unit of the air conditioner of the first example.

FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3.

FIG. 6 is a front view of an indoor heat exchanger, a liquid-refrigerant connection pipe, and a gas-refrigerant connection pipe of the indoor unit of the first example.

FIG. 7 is a schematic front view of a main portion of the indoor heat exchanger of the indoor unit of the first example.

FIG. 8 is a schematic front view of the main portion of the indoor heat exchanger of the indoor unit of the first example.

FIG. 9 is a right-side view of the indoor heat exchanger, the liquid-refrigerant connection pipe, and the gas-refrigerant connection pipe of the indoor unit of the first example.

FIG. 10 is a schematic front view of a main portion of an indoor unit of a second example of the present disclosure.

FIG. 11 is a schematic front view of a main portion of an indoor unit of a third example of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

An indoor unit and an air conditioner of the present disclosure will be described in detail below with reference to embodiments illustrated in the drawings. Note that the same parts in the drawings are denoted by the same reference numerals to avoid the description from being redundant. Upper, lower, left, and right in the description correspond to upper, lower, left, and right in a state where an indoor unit is installed in a room.

FIRST EXAMPLE

FIG. 1 is a diagram illustrating a refrigerant circuit RC provided in an air conditioner including an indoor unit 1 of a first example of the present disclosure. The air conditioner of the first example includes the indoor unit 1 and an outdoor unit 2 connected to the indoor unit 1 via the refrigerant circuit RC. The air conditioner is of a type in which the outdoor unit 2 is paired one-to-one with the indoor unit 1.

The refrigerant circuit RC includes a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, an electric expansion valve 14, an indoor heat exchanger 15, and an accumulator 16. As the compressor 11 is driven, a refrigerant (for example, an HFC refrigerant such as R410A or R32) circulates in the refrigerant circuit RC. The indoor heat exchanger 15 is an example of a heat exchanger.

More specifically, the four-way switching valve 12 has one end connected to a discharge side of the compressor 11. The four-way switching valve 12 has the other end connected to one end of the outdoor heat exchanger 13. The outdoor heat exchanger 13 has the other end connected to one end of the electric expansion valve 14. The electric expansion valve 14 has the other end connected to one end of the indoor heat exchanger 15 via a shutoff valve V1 and a connection pipe L1. The indoor heat exchanger 15 has the other end connected to one end of the accumulator 16 via a connection pipe L2, a shutoff valve V2, and the four-way switching valve 12. The accumulator 16 has the other end connected to an intake-side portion of the compressor 11.

The indoor unit 1 is equipped with the indoor heat exchanger 15 and an indoor fan 18. The indoor fan 18 is, for example, a cross-flow fan, and takes in indoor air through the indoor heat exchanger 15.

The outdoor unit 2 is equipped with the compressor 11, the four-way switching valve 12, the outdoor heat exchanger 13, the electric expansion valve 14, the accumulator 16, and an outdoor fan 17.

The air conditioner switches the four-way switching valve 12 to a switching position indicated by a solid line to activate the compressor 11 for cooling operation and dehumidifying operation, and switches the four-way switching valve 12 to a switching position indicated by a dotted line to activate the compressor 11 for heating operation.

A direction of a solid arrow in FIG. 1 indicates a direction in which the refrigerant flows during the cooling operation and the dehumidifying operation. A direction indicated by a dotted arrow in FIG. 1 indicates a direction in which the refrigerant flows during the heating operation.

FIG. 2 is a perspective view of the indoor unit 1 as viewed obliquely from above, and FIG. 3 is a front view of the indoor unit 1.

As illustrated in FIGS. 2 and 3, the indoor unit 1 includes a casing 21, and the indoor heat exchanger 15 (illustrated in FIG. 1), the indoor fan 18 (illustrated in FIG. 1), and the like are accommodated in the casing 21.

An upper portion of the casing 21 is provided with an intake port 22 through which indoor air is taken in. When the indoor fan 18 is driven, indoor air enters the casing 21 through the intake port 22 and flows toward the indoor fan 18 (cross-flow fan). At this time, in order to prevent dust and the like from entering the casing 21 together with indoor air, a filter (not illustrated) is attached to the intake port 22.

A lower portion of the casing 21 is provided with a blow-out port 23 through which air from the indoor fan 18 (indoor air subjected to heat exchange with the indoor heat exchanger 15) blows out. A horizontal flap 24 is rotatably attached to a peripheral edge portion of the blow-out port 23.

When the cooling operation or the like is started, the horizontal flap 24 changes its position from a stop position to close the blow-out port 23 to an operation position to open the blow-out port 23 to adjust a vertical airflow direction of air blown out from the blow-out port 23.

FIG. 4 is a rear perspective view of the indoor unit 1, and FIG. 5 is a cross-sectional view taken along line V-V in FIG. 3. In FIG. 5, a reference numeral 28 denotes an electric component portion.

As illustrated in FIGS. 4 and 5, the casing 21 of the indoor unit 1 includes a bottom frame 25, a front grille 26 attached to the bottom frame 25 and having a substantially rectangular opening (not illustrated) provided on a front surface, and a front panel 27 attached to cover the opening of the front grille 26. The front grille 26 surrounds a front surface, an upper surface, a lower surface, and both side surfaces of the bottom frame 25. A rear surface of the bottom frame 25 is attached to an indoor wall surface with an attachment plate (not illustrated) interposed between the rear surface and the indoor wall surface.

In the casing 21, a first space 21a surrounded by the bottom frame 25, the front grille 26, and the front panel 27 is formed. The first space 21a is a main area in the casing 21. An inner section of a liquid-refrigerant connection pipe 31 and an inner section of a gas-refrigerant connection pipe 32 are accommodated in the first space 21a.

A second space 30a (pipe rising portion) is formed on a right side of the bottom frame 25 along an up-down direction. A third space 30b is formed, extending in a left-right direction, on the rear surface of and below the bottom frame 25 so as to be continuous with a lower end of the second space 30a.

The liquid-refrigerant connection pipe 31 and the gas-refrigerant connection pipe 32 are disposed extending from the indoor heat exchanger 15 in the first space 21a along the second space 30a and the third space 30b. A vertical section of the liquid-refrigerant connection pipe 31 and a vertical section of the gas-refrigerant connection pipe 32 are accommodated in the second space 30a. A horizontal section of the liquid-refrigerant connection pipe 31 and a horizontal section of the gas-refrigerant connection pipe 32 are accommodated in the third space 30b. The liquid-refrigerant connection pipe 31 and the gas-refrigerant connection pipe 32 are led out of the casing 21 from a space above a drain pan 29 (illustrated in FIGS. 7 and 8) provided in the bottom frame 25.

The second space 30a and the third space 30b are not located in the casing 21 and are located outside of the rear of the bottom frame 25, i.e., are a space behind the bottom frame 25. In other words, the second space 30a and the third space 30b are located outside the casing 21.

FIG. 6 is a front view of the indoor heat exchanger 15, the liquid-refrigerant connection pipe 31, and the gas-refrigerant connection pipe 32.

As illustrated in FIG. 6, the indoor heat exchanger 15 includes a heat exchange portion 151 and a plurality of heat transfer tubes 152 extending through the heat exchange portion 151 in a left-right direction. The heat exchange portion 151 and the heat transfer tubes 152 are each formed of aluminum or an aluminum alloy.

The indoor unit 1 further includes the liquid-refrigerant connection pipe 31 and the gas-refrigerant connection pipe 32, the liquid-refrigerant connection pipe 31 and the gas-refrigerant connection pipe 32 being fluidly connected to the heat transfer tubes 152 of the indoor heat exchanger 15. The liquid-refrigerant connection pipe 31 is an example of a first connection pipe, and constitutes a part of the connection pipe L1 (illustrated in FIG. 1). The gas-refrigerant connection pipe 32 is an example of a second connection pipe, and constitutes a part of the connection pipe L2 (illustrated in FIG. 1). The liquid-refrigerant connection pipe 31 guides a liquid refrigerant from the electric expansion valve 14 to the indoor heat exchanger 15 during the cooling operation and the dehumidifying operation. On the other hand, the gas-refrigerant connection pipe 32 guides a gas refrigerant from the indoor heat exchanger 15 to the compressor 11 during the cooling operation and the dehumidifying operation.

FIG. 7 is a schematic front view of a main portion of the indoor heat exchanger 15, FIG. 8 is a schematic front view of the main portion of the indoor heat exchanger 15, and FIG. 9 is a right-side view of the indoor heat exchanger 15, the liquid-refrigerant connection pipe 31, and the gas-refrigerant connection pipe 32. In FIGS. 7 and 8, a reference numeral 29 denotes the drain pan disposed in the casing 21 and below the indoor heat exchanger 15. In FIGS. 8 and 9, a tubular member 61 is not illustrated.

<Configuration of Liquid-Refrigerant Connection Pipe 31>

The liquid-refrigerant connection pipe 31 includes a first liquid-refrigerant pipe 311 formed of aluminum or an aluminum alloy, a second liquid-refrigerant pipe 312 formed of copper or a copper alloy, and a connection portion 313 formed of copper or a copper alloy that connects between the first liquid-refrigerant pipe 311 and the second liquid-refrigerant pipe 312. The first liquid-refrigerant pipe 311 is an example of a first refrigerant pipe or a first-first refrigerant pipe, and the second liquid-refrigerant pipe 312 is an example of a second refrigerant pipe or a second-first refrigerant pipe. The aluminum and the aluminum alloy are each an example of a first metal. The copper and the copper alloy are each an example of a second metal.

The second liquid-refrigerant pipe 312 has one end connected to one end of the connection portion 313 by copper-copper bonding. The connection portion 313 has the other end connected to the heat transfer tube 152 of the indoor heat exchanger 15 through the first liquid-refrigerant pipe 311 formed of aluminum or an aluminum alloy.

The second liquid-refrigerant pipe 312 has the other end fixed to a liquid-refrigerant flare union 41 by brazing.

<Configuration of Gas-Refrigerant Connection Pipe 32>

The gas-refrigerant connection pipe 32 is similar in configuration to the liquid-refrigerant connection pipe 31, and includes a first gas-refrigerant pipe 321 formed of aluminum or an aluminum alloy, a second gas-refrigerant pipe 322 formed of copper or a copper alloy, and a connection portion 323 formed of copper or a copper alloy that connects between the first gas-refrigerant pipe 321 and the second gas-refrigerant pipe 322. The first gas-refrigerant pipe 321 is an example of the first refrigerant pipe or a first-second refrigerant pipe (a third refrigerant pipe). The second gas-refrigerant pipe 322 is an example of the second refrigerant pipe or a second-second refrigerant pipe (a fourth refrigerant pipe).

The second gas-refrigerant pipe 322 has one end connected to one end of the connection portion 323 by copper-copper bonding. The connection portion 323 has the other end connected to the heat transfer tube 152 of the indoor heat exchanger 15 through the first gas-refrigerant pipe 321 formed of aluminum or an aluminum alloy.

The second gas-refrigerant pipe 322 has the other end fixed to a gas-refrigerant flare union 42 by brazing.

<Configuration of Second Liquid-Refrigerant Pipe 312 on a Side Remote From First Liquid-Refrigerant Pipe 311>

As illustrated in FIG. 7, the second liquid-refrigerant pipe 312 of the liquid-refrigerant connection pipe 31 includes a first section 312a extending along an approximate vertical direction. The approximate vertical direction means a vertical direction or a direction inclined at an angle of, for example, 20 degrees or less relative to the vertical direction. The second liquid-refrigerant pipe 312 further includes a second section 312b closer to the liquid-refrigerant flare union 41 than the first section 312a. The second section 312b is continuous with a lower end (a liquid-refrigerant-flare union 41-side end) of the first section 312a, and is bent from the lower end toward the liquid-refrigerant flare union 41.

The second liquid-refrigerant pipe 312 further includes a third section 312ccloser to the liquid-refrigerant flare union 41 than the second section 312b. The third section 312c extends along an approximate horizontal direction. The approximate horizontal direction means a horizontal direction or a direction inclined at an angle of, for example, 20 degrees or less relative to the horizontal direction.

<Configuration of Second Liquid-Refrigerant Pipe 312 on a Side Close to the Indoor Heat Exchanger 15>

The second liquid-refrigerant pipe 312 includes a fourth section 312d closer to the indoor heat exchanger 15 than the first section 312a. The fourth section 312dextends upward from an upper end of the first section 312a and then extends downward like a U-turn.

The second liquid-refrigerant pipe 312 further includes a fifth section 312e closer to the indoor heat exchanger 15 than the fourth section 312d. The fifth section 312e is an example of a bent section. The fifth section 312e extends downward from an end of the fourth section 312d and then extends upward like a U-turn. The fifth section 312ehas an end adjacent to the indoor heat exchanger 15, the end being connected to the one end of the connection portion 313 formed of copper or a copper alloy. In other words, the indoor-heat-exchanger 15-side end of the fifth section 312e is connected to the one end of the connection portion 313 formed of copper or a copper alloy.

The connection portion 313 has the other end (end adjacent to the indoor heat exchanger 15) fixed to the first liquid-refrigerant pipe 311 formed of aluminum or an aluminum alloy by brazing. The connection portion 313 has the other end connected to the heat exchange portion 151 through the first liquid-refrigerant pipe 311.

In the first example, the gas-refrigerant connection pipe 32 is similar in configuration to the liquid-refrigerant connection pipe 31.

The second liquid-refrigerant pipe 312 is covered with the tubular member 61 from the fourth section 312d to the vicinity of the liquid-refrigerant flare union 41. The tubular member 61 is formed of a heat insulating material (for example, foamed polyester).

Although not illustrated, most of the gas-refrigerant connection pipe 32 is inserted into the tubular member 61 in a manner similar to the liquid-refrigerant connection pipe 31. Therefore, the tubular member 61 has an inner diameter set larger than a sum of an outer diameter of the liquid-refrigerant connection pipe 31 and an outer diameter of the gas-refrigerant connection pipe 32.

A joint portion between the connection portion 313 and the first liquid-refrigerant pipe 311 is covered with a waterproof tube 51. The waterproof tube 51 is formed of a tube made of a waterproof material (for example, vinyl chloride, silicone rubber, fluorine-based polymer, or the like) and shrunk by heating.

In the casing 21, the liquid-refrigerant connection pipe 31 is disposed above the gas-refrigerant connection pipe 32.

In the indoor unit 1 configured as described above, as illustrated in FIGS. 7, 8, and 9, the second liquid-refrigerant pipe 312 (second refrigerant pipe) is formed of the second metal (copper or copper alloy in this example) that is higher in potential than the first metal (aluminum or aluminum alloy in this example) of the first liquid-refrigerant pipe 311 (first refrigerant pipe), the second liquid-refrigerant pipe 312 having the one end connected to the other end of the first liquid-refrigerant pipe 311 in the casing 21. The second gas-refrigerant pipe 322 (second refrigerant pipe) formed of the second metal (copper or copper alloy in this example) that is higher in potential than the first metal (aluminum or aluminum alloy in this example) of the second gas-refrigerant pipe 322 (first refrigerant pipe), the second gas-refrigerant pipe 322 having one end connected to the other end of the first liquid-refrigerant pipe 311 in the casing 21. As a result, the connection point between aluminum (or aluminum alloy) and copper (or copper alloy) is located in the internal space of the casing 21 that is not covered with an anti-dew tube or the like, so that it is possible to prevent the connection point from suffering dew condensation and thus prevent the refrigerant pipes from suffering electrolytic corrosion.

The first liquid-refrigerant pipe 311 and the second liquid-refrigerant pipe 312 are connected to each other through the connection portion 313 in this example, or alternatively, the first liquid-refrigerant pipe 311 and the second liquid-refrigerant pipe 312 may be directly connected to each other without the connection portion. The first gas-refrigerant pipe 321 and the second gas-refrigerant pipe 322 are connected to each other through the connection portion 323, or alternatively, the first gas-refrigerant pipe 321 and the second gas-refrigerant pipe 322 may be directly connected to each other without the connection portion.

In the indoor unit 1, the other end of the first liquid-refrigerant pipe 311 is located above the one end of the second liquid-refrigerant pipe 312, so that even when dew condensation occurs in the second liquid-refrigerant pipe 312, dew condensation water does not flow to the first liquid-refrigerant pipe 311 and drops from the fifth section 312e (bent section), and it is therefore possible to reliably prevent the occurrence of electrolytic corrosion (the same applies to the gas-refrigerant connection pipe 32).

The connection portion 313 (other part) where the one end of the second liquid-refrigerant pipe 312 is connected to the other end of the first liquid-refrigerant pipe 311 is not covered with the tubular member 61, so that it is possible to reduce the risk of the occurrence of electrolytic corrosion due to dew condensation water accumulated in the tubular member 61 (the same applies to the gas-refrigerant connection pipe 32).

The fifth section 312e (bent section) that is bent to protrude downward from the second liquid-refrigerant pipe 312 is disposed in the casing 21, so that dew condensation water generated in the second liquid-refrigerant pipe 312 drops from the bent section without flowing from the second liquid-refrigerant pipe 312 to the first liquid-refrigerant pipe 311, and it is therefore possible to reliably prevent the occurrence of electrolytic corrosion (the same applies to the gas-refrigerant connection pipe 32).

Further, the indoor unit 1 can prevent the refrigerant pipes of both the liquid-refrigerant connection pipe 31 (first connection pipe) and the gas-refrigerant connection pipe 32 (second connection pipe) from suffering dew condensation and thus prevent the occurrence of electrolytic corrosion.

The other end of the first liquid-refrigerant pipe 311 (first-first refrigerant pipe) that is a liquid pipe is disposed above the one end of the second gas-refrigerant pipe (second-second refrigerant pipe) 322 that is a gas pipe, so that the second gas-refrigerant pipe 322 larger in dew condensation amount is disposed below, and it is therefore possible to prevent the first liquid-refrigerant pipe 311 located above from suffering electrolytic corrosion.

As the casing 21 is viewed from above, the first liquid-refrigerant pipe 311 (first-first refrigerant pipe) and the first gas-refrigerant pipe 321 (second-second refrigerant pipe) do not overlap each other, so that it is possible to prevent dew condensation water dropped from the first gas-refrigerant pipe 321 from hitting the first liquid-refrigerant pipe 311 and thus prevent the first liquid-refrigerant pipe 311 from suffering electrolytic corrosion.

As the casing 21 is viewed from above, the fifth section 312e (bent section) of the second liquid-refrigerant pipe 312 and the electric component (for example, the electric component portion 28) in the casing 21 do not overlap each other, so that it is possible to prevent dew condensation water dropped from the second liquid-refrigerant pipe 312 from hitting the electric component.

The one end of the second liquid-refrigerant pipe 312 is connected to the other end of the first liquid-refrigerant pipe 311 through the connection portion 313 above the drain pan 29 provided in the casing 21, so that it is possible to cause the drain pan 29 to receive dew condensation water dropped from the connection portion 313 and drain the dew condensation water together with drain water.

SECOND EXAMPLE

FIG. 10 is a schematic front view of a main portion of an indoor unit 1 of a second example of the present disclosure. The indoor unit 1 of the second example is similar in configuration to the indoor unit 1 of the first example except for the waterproof tube 51.

As illustrated in FIG. 10, in the indoor unit 1 of the second example, a section extending from the joint portion between the connection portion 313 and the first liquid-refrigerant pipe 311 to the fourth section 312d is covered with the waterproof tube 51. It is therefore possible to prevent the occurrence of dew condensation water from the second liquid-refrigerant pipe 312 formed of copper or a copper alloy.

The indoor unit 1 of the second example has effects similar to the effects of the indoor unit 1 of the first example.

THIRD EXAMPLE

FIG. 11 is a schematic front view of a main portion of an indoor unit 1 of a third example of the present disclosure. The indoor unit 1 of the third example is similar in configuration to the indoor unit 1 of the first example except for an additional refrigerant pipe 314.

As illustrated in FIG. 11, in the indoor unit 1 of the third example, the connection portion 313 and the first liquid-refrigerant pipe 311 are connected to each other through the additional refrigerant pipe 314 formed of stainless steel. This makes brazing between the first liquid-refrigerant pipe 311 formed of aluminum or an aluminum alloy and the additional refrigerant pipe 314 formed of stainless steel and brazing between the connection portion 313 formed of copper or a copper alloy and the additional refrigerant pipe 314 formed of stainless steel easier than bonding between aluminum and copper.

In the air conditioners of the first to third examples, one indoor unit 1 is connected to one outdoor unit 2, or alternatively, a plurality of indoor units 1 maybe connected. In other words, the above-described air conditioner is of a pair-type, or alternatively, the air conditioner may be of a multi-type.

The first liquid-refrigerant pipe 311 and the first gas-refrigerant pipe 321 as the first refrigerant pipe are formed of aluminum or an aluminum alloy in the first to third examples, or alternatively, may be formed of metal other than aluminum and an aluminum alloy.

The second liquid-refrigerant pipe 312 and the second gas-refrigerant pipe 322 as the second refrigerant pipe are formed of copper or a copper alloy in the first to third examples, or alternatively, may be formed of metal that is other than copper or a copper alloy and is higher in potential than the metal of the first refrigerant pipe.

The indoor heat exchanger 15 and the first liquid-refrigerant pipe 311 are connected to each other in the liquid-refrigerant connection pipe 31 in the first to third examples, or alternatively, a flow divider may be interposed between the indoor heat exchanger 15 and the first liquid-refrigerant pipe 311 to connect a plurality of the first liquid-refrigerant pipes 311 to the indoor heat exchanger 15 (the same applies to the gas-refrigerant connection pipe 32).

Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present disclosure. Accordingly, the scope of the disclosure should be limited only by the attached claims.

REFERENCE SIGNS LIST

• • 1 indoor unit
  • 15 indoor heat exchanger
  • 21 casing
  • 21 a first space
  • 22 intake port
  • 23 blow-out port
  • 24 horizontal flap
  • 25 bottom frame
  • 26 front grille
  • 27 front panel
  • 28 electrical component portion
  • 29 drain pan
  • 30 a second space
  • 30 b third space
  • 31 liquid-refrigerant connection pipe (first connection pipe)
  • 32 gas-refrigerant connection pipe (second connection pipe)
  • 41 liquid-refrigerant flare union
  • 42 gas-refrigerant flare union
  • 51 waterproof tube
  • 61 tubular member
  • 151 heat exchange portion
  • 152 heat transfer tube
  • 311 first liquid-refrigerant pipe (first refrigerant pipe or first-first refrigerant pipe)
  • 312 second liquid-refrigerant pipe (second refrigerant pipe or second-first refrigerant pipe)
  • 312 a first section (vertical straight section)
  • 312 b second section (bent section)
  • 312 c third section (horizontal straight section)
  • 312 d fourth section (curved section)
  • 312 e fifth section (bent connecting section)
  • 313 connection portion
  • 321 first gas-refrigerant pipe (first refrigerant pipe or first-second refrigerant pipe (third refrigerant pipe))
  • 322 second gas-refrigerant pipe (second refrigerant pipe or second-second refrigerant pipe (fourth refrigerant pipe))
  • 323 connection portion

Claims

1. An indoor unit comprising: a casing;a heat exchanger accommodated in the casing; anda connection pipe, connected to the heat exchanger, through which a refrigerant flows, whereinthe connection pipe includes a first refrigerant pipe made of a first metal and a second refrigerant pipe made of a second metal higher in potential than the first metal, andone end of the first refrigerant pipe is connected to the heat exchanger, and the other end of the first refrigerant pipe is connected to one end of the second refrigerant pipe in the casing.

2. The indoor unit according to claim 1, wherein the other end of the first refrigerant pipe is above the one end of the second refrigerant pipe.

3. The indoor unit according to claim 1, further comprising: a tubular member that covers a part of the connection pipe but does not cover the other part of the connection pipe, whereinin the other part of the connection pipe, the other end of the first refrigerant pipe is connected to the one end of the second refrigerant pipe.

4. The indoor unit according to claim 1, wherein the second refrigerant pipe includes a bent section that is bent to protrude downward and that is in the casing.

5. An indoor unit comprising: a casing;a heat exchanger accommodated in the casing;a first connection pipe, through which a refrigerant flows, including a first refrigerant pipe made of a first metal and a second refrigerant pipe made of a second metal higher in potential than the first metal, wherein one end of the first refrigerant pipe is connected to the heat exchanger, and the other end of the first refrigerant pipe is connected to one end of the second refrigerant pipe in the casing, anda second connection pipe, through which a refrigerant flows, including a third refrigerant pipe made of the first metal and a fourth refrigerant pipe made of the second metal, wherein one end of the third refrigerant pipe is connected to the heat exchanger, and the other end of the third refrigerant pipe is connected to one end of the fourth refrigerant pipe in the casing.

6. The indoor unit according to claim 5, wherein the first connection pipe is a liquid pipe,the second connection pipe is a gas pipe, andthe other end of the first refrigerant pipe is above the one end of the fourth refrigerant pipe in the casing.

7. The indoor unit according to claim 6, wherein the first refrigerant pipe does not overlap the fourth refrigerant pipe as the casing is viewed from above.

8. The indoor unit according to claim 4, wherein the bent section does not overlap an electric component in the casing as the casing is viewed from above.

9. The indoor unit according to claim 1, wherein the other end of the first refrigerant pipe is connected to the one end of the second refrigerant pipe above a drain pan in the casing.

10. An air conditioner comprising the indoor unit according to claim 1.