Air conditioner

Abstract

The purpose of the present invention is to reduce a noise that is caused by the flow of a refrigerant. This air conditioner is provided with: a compressor that compresses a refrigerant; a heat exchanger (9) that exchanges heat between the refrigerant and another medium; an expansion valve that expands the refrigerant; a supercooling heat exchanger (20) that supercools the refrigerant; and refrigerant supply lines (30, 40) that supply the refrigerant to the supercooling heat exchanger (20). The refrigerant supply lines (30, 40) has: branch pipes (32) which cause the refrigerant to branch into a plurality of branch parts; first turbulence inhibition pipes (33, 43) each having one end connected to one of the plurality of branch parts; and second turbulence inhibition pipes (34, 44) each having one end connected to one of the plurality of branch parts. The other ends of the first turbulence inhibition pipes (33, 43) and the second turbulence inhibition pipes (34, 44) are connected to the supercooling heat exchanger (20).

Description

air conditioner

[0001] The present disclosure relates to an air conditioner.

[0002] An air conditioner is known that has a heat exchanger in which multiple tubes are arranged between multiple header pipes, connecting multiple refrigerant passages inside the tubes to the inside of the header pipes, and fins are arranged between the tubes (for example, Patent Document 1).

[0003] JP 2013-178007 A

[0004] Such air conditioners may be equipped with a subcooling heat exchanger that supercools the refrigerant. When supplying the refrigerant to the subcooling heat exchanger, the refrigerant may be branched into multiple paths using branch pipes or the like to prevent the refrigerant from flowing too fast. However, the refrigerant immediately after branching is in a turbulent state. When turbulent refrigerant flows into the subcooling heat exchanger, it generates refrigerant flow noise, potentially increasing the noise level of the air conditioner.

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide an air conditioner that can reduce noise caused by the flow of refrigerant.

[0006] To solve the above problems, an air conditioner according to one aspect of the present disclosure employs the following measures: An air conditioner according to one aspect of the present disclosure includes a compressor that compresses a refrigerant, a heat exchanger that exchanges heat between the refrigerant and another medium, an expansion valve that expands the refrigerant, a subcooling heat exchanger that subcools the refrigerant, and a refrigerant supply line that supplies refrigerant to the subcooling heat exchanger, wherein the refrigerant supply line has a branch pipe that branches the refrigerant into a plurality of branch sections, a first turbulence suppression pipe having one end connected to one of the plurality of branch sections, and a second turbulence suppression pipe having one end connected to one of the plurality of branch sections, and the other ends of the first turbulence suppression pipe and the second turbulence suppression pipe are connected to the subcooling heat exchanger.

[0007] According to the present disclosure, noise caused by the flow of refrigerant can be reduced.

[0008] Fig. 1 is a schematic configuration diagram showing a refrigerant circuit of an air conditioner according to an embodiment of the present disclosure; Fig. 2 is a perspective view showing a main part of an outdoor unit of an air conditioner according to an embodiment of the present disclosure; Fig. 3 is a plan view showing a first refrigerant supply line according to an embodiment of the present disclosure; Fig. 4 is a front view showing a first refrigerant supply line according to an embodiment of the present disclosure; Fig. 5 is a plan view showing a second refrigerant supply line according to an embodiment of the present disclosure; Fig. 6 is a front view showing a second refrigerant supply line according to an embodiment of the present disclosure; Fig. 7 is a graph showing the relationship between sound pressure level and frequency of noise generated in an air heat exchanger according to an embodiment of the present disclosure;

[0009] An embodiment of an air conditioner according to the present disclosure will be described below with reference to the drawings. Fig. 1 shows the refrigerant circuit configuration of an air conditioner 1 of this embodiment. The air conditioner 1 can perform heating operation and cooling operation by switching the flow direction of the refrigerant using a four-way valve 4 provided on the discharge side of a compressor 3. The heating operation is an operation in which water (heat medium) is heated in a water heat exchanger 5, and the cooling operation is an operation in which water is cooled in the water heat exchanger 5. In Fig. 1, the dashed arrow indicates the flow direction of the refrigerant during heating operation, and the solid arrow indicates the flow direction of the refrigerant during cooling operation.

[0010] The air conditioner 1 uses, for example, R32 as a refrigerant. R32 is a low boiling point refrigerant with a low global warming potential (GWP). However, other refrigerants may be used instead of R32.

[0011] The air conditioner 1 includes a compressor 3 that compresses a refrigerant, a four-way valve 4, a water heat exchanger 5, a receiver 7, an expansion valve 8, an air heat exchanger 9, and an accumulator 10. A refrigerant circuit that performs a refrigeration cycle is formed by connecting the compressor 3, four-way valve 4, water heat exchanger 5, receiver 7, expansion valve 8, air heat exchanger 9, and accumulator 10 via refrigerant piping. In the air conditioner 1 of this embodiment, the compressor 3, four-way valve 4, water heat exchanger 5, receiver 7, expansion valve 8, air heat exchanger 9, and accumulator 10 are all housed inside the outdoor unit 2. In the air conditioner 1, water heated or cooled in the water heat exchanger 5 is guided via water piping 16 to a destination (e.g., an indoor unit) outside the outdoor unit 2.

[0012] The compressor 3 is, for example, a scroll compressor or a rotary compressor, and a compression mechanism such as a scroll compression mechanism or a rotary compression mechanism is provided inside the housing of the compressor 3. The compression mechanism is driven by an electric motor (not shown). The electric motor is equipped with an inverter device, and the rotation speed can be changed as desired in response to a command from a control unit (not shown).

[0013] A muffler 12 is provided on the discharge side of the compressor 3 to reduce noise generated by the discharged refrigerant.

[0014] The four-way valve 4 is switched so that the refrigerant discharged from the compressor 3 is guided to the water heat exchanger 5 during heating operation, and is switched so that the refrigerant discharged from the compressor 3 is guided to the air heat exchanger 9 during cooling operation. The four-way valve 4 is controlled by a control unit (not shown).

[0015] The water heat exchanger 5 operates as a condenser during heating operation and as an evaporator during cooling operation. A water pipe 16 for circulating water between the water heat exchanger 5 and an external load (destination of use) is connected to the water heat exchanger 5. Heat is exchanged between the water introduced from the water pipe 16 and the refrigerant in the water heat exchanger 5.

[0016] When the expansion valve 8 operates as a condenser, it expands the refrigerant condensed and liquefied in the air heat exchanger 9. The opening degree of the expansion valve 8 is controlled by the control unit.

[0017] A strainer 13 is provided on the water heat exchanger 5 side of the expansion valve 8 to collect foreign matter contained in the refrigerant flowing into the expansion valve 8 during heating operation. Also, a strainer 14 is provided on the air heat exchanger 9 side of the expansion valve 8 to collect foreign matter contained in the refrigerant flowing into the expansion valve 8 during cooling operation.

[0018] The receiver 7 is provided closer to the water heat exchanger 5 than the expansion valve 8, and is a container that temporarily stores a portion of the refrigerant expanded by the expansion valve 8. The capacity (size) of the receiver 7 is determined according to the amount of refrigerant circulating in the refrigerant circuit.

[0019] The air heat exchanger 9 functions as an evaporator during heating operation and as a condenser during cooling operation. Heat is exchanged between the refrigerant and air in the air heat exchanger 9. Air is sent to the air heat exchanger 9 from a fan (not shown).

[0020] A distributor 9a is provided on the expansion valve 8 side of the air heat exchanger 9. During heating operation, the distributor 9a distributes the refrigerant condensed in the water heat exchanger 5 to multiple heat transfer tubes provided in the air heat exchanger 9. During cooling operation, the distributor 9a collects the refrigerant condensed in the multiple heat transfer tubes of the air heat exchanger 9.

[0021] A gas header 9b is provided on the four-way valve 4 side of the air heat exchanger 9. During cooling operation, the gas header 9b distributes the gas phase refrigerant compressed by the compressor 3 to the multiple heat transfer tubes provided in the air heat exchanger 9. During heating operation, the gas header 9b collects the refrigerant evaporated in the multiple heat transfer tubes of the air heat exchanger 9.

[0022] The accumulator 10 is provided on the upstream side of the compressor 3, that is, on the refrigerant intake side, and is a container for temporarily storing the refrigerant evaporated in the air heat exchanger 9 or the water heat exchanger 5.

[0023] A subcooling heat exchanger 20 is provided between the expansion valve 8 and the air heat exchanger 9. During heating operation, the subcooling heat exchanger 20 subcools the liquid-phase refrigerant introduced into the air heat exchanger 9. During cooling operation, the subcooling heat exchanger 20 subcools the liquid-phase refrigerant discharged from the air heat exchanger 9.

[0024] A first refrigerant supply line 30 is connected to the subcooling heat exchanger 20. The first refrigerant supply line 30 supplies refrigerant to the subcooling heat exchanger 20 during heating operation. The first refrigerant supply line 30 connects the expansion valve 8 and the subcooling heat exchanger 20. A second refrigerant supply line 40 is connected to the subcooling heat exchanger 20. The second refrigerant supply line 40 supplies refrigerant to the subcooling heat exchanger 20 during cooling operation. The second refrigerant supply line 40 connects the air heat exchanger 9 (more specifically, the distributor 9a) and the subcooling heat exchanger 20.

[0025] Next, the details of the subcooling heat exchanger 20, the first refrigerant supply line 30, and the second refrigerant supply line 40 will be described using Figures 2 to 6. The subcooling heat exchanger 20 is provided below the air heat exchanger 9. In detail, the subcooling heat exchanger 20 and the air heat exchanger 9 are integrally formed, and of the heat transfer tubes (not shown) provided in multiple layers in the vertical direction, the heat transfer tubes provided in the lowest and second-lowest rows are the subcooling heat exchanger 20. The heat transfer tubes provided above the third-lowest row are the air heat exchanger 9.

[0026] As shown in Figures 2 to 4, the first refrigerant supply line 30 has a single pipe 31, a branch pipe 32 connected to the single pipe 31, a first turbulence suppression pipe 33 connected to one branch portion 32b of the branch pipe 32, and a second turbulence suppression pipe 34 connected to the other branch portion 32b of the branch pipe 32.

[0027] One end of the single pipe 31 is connected to the expansion valve 8. The other end of the single pipe 31 is connected to the branch pipe 32.

[0028] As shown in Fig. 3, the branch pipe 32 is generally Y-shaped. The branch pipe 32 has one main portion 32a and two branch portions 32b branching off from the main portion 32a. The main portion 32a is connected to the single pipe 31. Each branch portion 32b is connected to a first turbulence suppression pipe 33 or a second turbulence suppression pipe 34.

[0029] 3, one end of the first turbulence suppression pipe 33 and the second turbulence suppression pipe 34 is connected to the branch portion 32b of the branch pipe 32. The other end of the first turbulence suppression pipe 33 and the second turbulence suppression pipe 34 is connected to the subcooling heat exchanger 20. The first turbulence suppression pipe 33 and the second turbulence suppression pipe 34 integrally have a portion that extends obliquely downward from the branch pipe 32 and a portion that extends from the oblique portion and bends in a substantially horizontal direction.

[0030] The first turbulence suppression pipe 33 and the second turbulence suppression pipe 34 are connected to the subcooling heat exchanger 20 without passing through a muffler.

[0031] As shown in Figures 2, 5, and 6, the second refrigerant supply line 40 has a single pipe 41, a branch pipe 42 connected to the single pipe 41, a first turbulence suppression pipe 43 connected to one branch portion 42b of the branch pipe 42, and a second turbulence suppression pipe 44 connected to the other branch portion 42b of the branch pipe 42.

[0032] One end of the single pipe 41 is connected to the distributor 9a of the air heat exchanger 9. The other end of the single pipe 41 is connected to a branch pipe .

[0033] As shown in Fig. 5, the branch pipe 42 is generally Y-shaped. The branch pipe 42 has one main portion 42a and two branch portions 42b branching off from the main portion 42a. The main portion 42a is connected to the single pipe 41. Each branch portion 42b is connected to a first turbulence suppression pipe 43 or a second turbulence suppression pipe 44.

[0034] 5, one end of the first turbulence suppression pipe 43 and the second turbulence suppression pipe 44 is connected to the branch portion 42b of the branch pipe 42. The other end of the first turbulence suppression pipe 43 and the second turbulence suppression pipe 44 is connected to the subcooling heat exchanger 20. The first turbulence suppression pipe 43 and the second turbulence suppression pipe 44 integrally have a portion that extends obliquely downward from the branch pipe 42 and a portion that extends from the oblique portion and bends in a substantially horizontal direction.

[0035] The first turbulence suppression pipe 43 and the second turbulence suppression pipe 44 are connected to the subcooling heat exchanger 20 without passing through a muffler.

[0036] The length L of the first turbulence suppression pipe 33 (the length along the central axis of each pipe) is set to be 10 times or more the inner diameter D of the first turbulence suppression pipe 33. In other words, the length L of the first turbulence suppression pipe 33 is set so that the following equation (1) holds. This makes it possible to stabilize the turbulent flow of the refrigerant formed in the branch portion 32b by the first turbulence suppression pipe 33, thereby reducing noise caused by the turbulent flow.

[0037] L≧10D (1)

[0038] The first turbulence suppression pipe 33 can more effectively suppress turbulence if the length L is 11 times or more the inner diameter D of the first turbulence suppression pipe 33. Furthermore, the first turbulence suppression pipe 33 can even more effectively suppress turbulence if the length L is 15 times or more the inner diameter D of the first turbulence suppression pipe 33.

[0039] Similarly, the lengths of the second turbulence suppression pipe 34, the first turbulence suppression pipe 43, and the second turbulence suppression pipe 44 are also set to be 10 times or more the inner diameter of each pipe. Note that by setting the lengths of the second turbulence suppression pipe 34, the first turbulence suppression pipe 43, and the second turbulence suppression pipe 44 to be 11 times or more or 15 times or more the inner diameter of each pipe, the turbulence suppression effect is increased.

[0040] Next, the flow of refrigerant in the first refrigerant supply line 30 and the second refrigerant supply line 40 according to this embodiment will be described.

[0041] [Heating Operation] When the air conditioner 1 performs heating operation, the refrigerant expanded by the expansion valve 8 flows into the first refrigerant supply line 30. Specifically, the refrigerant first flows into the single pipe 31. The refrigerant flowing through the single pipe 31 branches at the branch pipe 32. At this time, a portion of the refrigerant becomes turbulent within the branch pipe 32. The refrigerant branched at the branch pipe 32 flows into the first turbulence suppression pipe 33 and the second turbulence suppression pipe 34. The refrigerant flowing through the first turbulence suppression pipe 33 and the second turbulence suppression pipe 34 gradually attenuates, and the turbulence disappears. In this way, the first refrigerant supply line 30 can stabilize the flow of the refrigerant. The refrigerant stabilized in the first refrigerant supply line 30 flows into the subcooling heat exchanger 20 and is subcooled. The subcooled refrigerant in the subcooling heat exchanger 20 is discharged into the second refrigerant supply line 40. The refrigerant discharged into the second refrigerant supply line 40 is guided to the air heat exchanger 9.

[0042] [Cooling Operation] When the air conditioner 1 is operating in cooling mode, the refrigerant that has completed heat exchange in the air heat exchanger 9 flows into the second refrigerant supply line 40. Specifically, the refrigerant first flows into the single pipe 41. The refrigerant flowing through the single pipe 41 branches at the branch pipe 42. At this time, a portion of the refrigerant becomes turbulent within the branch pipe 42. The refrigerant branched at the branch pipe 42 flows into the first turbulence suppression pipe 43 and the second turbulence suppression pipe 44. The refrigerant flowing through the first turbulence suppression pipe 43 and the second turbulence suppression pipe 44 gradually attenuates, and the turbulence disappears. In this way, the second refrigerant supply line 40 can stabilize the refrigerant flow. The refrigerant stabilized in the second refrigerant supply line 40 flows into the subcooling heat exchanger 20 and is subcooled. The subcooled refrigerant in the subcooling heat exchanger 20 is discharged into the first refrigerant supply line 30. The refrigerant discharged into the first refrigerant supply line 30 is guided to the expansion valve 8.

[0043] This embodiment provides the following advantageous effects. In this embodiment, the first refrigerant supply line 30 and the second refrigerant supply line 40 include first turbulence suppression pipes 33, 43 and second turbulence suppression pipes 34, 44. That is, the first turbulence suppression pipes 33, 43 and the second turbulence suppression pipes 34, 44 are provided between the branch pipe 32 and the subcooling heat exchanger 20. As a result, the turbulent refrigerant caused by branching at the branch pipe 32 attenuates as it flows through the first turbulence suppression pipes 33, 43 and the second turbulence suppression pipes 34, 44. This eliminates the turbulent state of the refrigerant. Therefore, the flow of the refrigerant flowing into the subcooling heat exchanger 20 can be stabilized. Therefore, since the refrigerant flows stably into the subcooling heat exchanger 20, noise caused by the refrigerant flow can be reduced. This can particularly reduce noise caused by the refrigerant flow in the high-frequency band (a frequency band of 5000 Hz or higher and 8000 Hz or lower).

[0044] Furthermore, in this embodiment, noise is reduced simply by providing the piping (first turbulence suppression pipes 33, 43 and second turbulence suppression pipes 34, 44). This allows for a simpler structure than, for example, when a noise reduction device (such as a muffler) is provided, and therefore allows for cost reduction.

[0045] In this embodiment, the longitudinal length L of the first turbulence suppression pipe 33, 43 is longer than 11 times the inner diameter D of the first turbulence suppression pipe 33, 43. This allows the length of the first turbulence suppression pipe 33, 43 to be sufficiently long. Therefore, the refrigerant is sufficiently stabilized inside the first turbulence suppression pipe 33, 43. Therefore, a stable refrigerant flows into the subcooling heat exchanger 20, reducing noise caused by the refrigerant flow.

[0046] The noise reduction effect will be explained using FIG. 7 . In FIG. 7 , the solid line shows the noise when the length L of the first turbulence suppression pipe 33 is 15 times the inner diameter D of the first turbulence suppression pipe 33. The dashed line shows the noise when the branch pipe 32 is directly connected to the subcooling heat exchanger 20 without providing the first turbulence suppression pipe 33 or the like. From the graph in FIG. 7 , it can be seen that when the length L of the first turbulence suppression pipe 33 is 15 times the inner diameter D of the first turbulence suppression pipe 33, the sound pressure level is reduced in the high frequency band. On the other hand, when the branch pipe 32 is directly connected to the subcooling heat exchanger 20, the sound pressure level is not reduced. It can also be seen that when the length L of the first turbulence suppression pipe 33 is 15 times the inner diameter D of the first turbulence suppression pipe 33, the sound pressure level is lower in the high frequency band compared to when the branch pipe 32 is directly connected to the subcooling heat exchanger 20. Therefore, it can be seen that when the length L of the first turbulence suppression pipe 33 is set to 15 times the inner diameter D of the first turbulence suppression pipe 33, there is an effect of reducing noise.

[0047] The present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure.

[0048] The air conditioner described in the above-described embodiment can be understood as follows, for example: The air conditioner according to a first aspect of the present disclosure includes a compressor (3) that compresses a refrigerant, a heat exchanger (5, 9) that exchanges heat between the refrigerant and another medium, an expansion valve (8) that expands the refrigerant, a subcooling heat exchanger (20) that subcools the refrigerant, and a refrigerant supply line (30, 40) that supplies the refrigerant to the subcooling heat exchanger, wherein the refrigerant supply line has a branch pipe (32) that branches the refrigerant into a plurality of branch portions (32b, 42b), a first turbulence suppression pipe (33, 43) having one end connected to one of the plurality of branch portions, and a second turbulence suppression pipe (34, 44) having one end connected to one of the plurality of branch portions, and the other ends of the first turbulence suppression pipe (33, 43) and the second turbulence suppression pipe (34, 44) are connected to the subcooling heat exchanger.

[0049] In the above configuration, the refrigerant supply line includes a first turbulence suppression pipe and a second turbulence suppression pipe. That is, the first turbulence suppression pipe and the second turbulence suppression pipe are provided between the branch pipe and the subcooling heat exchanger. As a result, the turbulent refrigerant caused by branching at the branch pipe attenuates as it flows through the first turbulence suppression pipe and the second turbulence suppression pipe. This eliminates the turbulent state of the refrigerant. This stabilizes the flow of refrigerant into the subcooling heat exchanger. This allows a stable flow of refrigerant into the subcooling heat exchanger, thereby reducing noise caused by the refrigerant flow. This reduces noise caused by the refrigerant flow, particularly in the high-frequency band (a frequency band of 5000 Hz or higher and 8000 Hz or lower).

[0050] Furthermore, in the above configuration, noise is reduced simply by providing piping. This simplifies the structure compared to when a noise reduction device (such as a muffler) is provided, and therefore reduces costs.

[0051] The length of the first turbulence suppression pipe may be set to a length that can sufficiently reduce the turbulence of the refrigerant generated at the branching portion.

[0052] Furthermore, in the air conditioner according to a second aspect of the present disclosure, in the above-described first aspect, the length in the longitudinal direction of the first turbulence suppression pipe is longer than 10 times the length of the inner diameter of the first turbulence suppression pipe.

[0053] In the above configuration, the longitudinal length of the first turbulence suppression pipe is longer than 11 times the inner diameter of the first turbulence suppression pipe. This allows the length of the first turbulence suppression pipe to be sufficiently long. Therefore, the refrigerant is sufficiently stabilized within the first turbulence suppression pipe. This allows a stable refrigerant to flow into the subcooling heat exchanger, reducing noise caused by the refrigerant flow.

[0054] DESCRIPTION OF SYMBOLS 1: Air conditioner 2: Outdoor unit 3: Compressor 4: Four-way valve 5: Water heat exchanger (heat exchanger) 7: Receiver 8: Expansion valve 9: Air heat exchanger (heat exchanger) 9a: Distributor 9b: Gas header 10: Accumulator 12: Muffler 13: Strainer 14: Strainer 16: Water piping 20: Subcooling heat exchanger 30: First refrigerant supply line (refrigerant supply line) 31: Single pipe 32: Branch pipe 32a: Single branch 32b: Branch section 33: First turbulence suppression pipe 34: Second turbulence suppression pipe 40: Second refrigerant supply line (refrigerant supply line) 41: Single pipe 42: Branch pipe 42a: Single branch 42b: Branch section 43 : First turbulence suppression pipe 44 : Second turbulence suppression pipe

Claims

1. An air conditioner comprising: a compressor that compresses a refrigerant; a heat exchanger that exchanges heat between the refrigerant and another medium; an expansion valve that expands the refrigerant; a subcooling heat exchanger that subcools the refrigerant; and a refrigerant supply line that supplies refrigerant to the subcooling heat exchanger, wherein the refrigerant supply line has: a branch pipe that branches the refrigerant into a plurality of branch sections; a first turbulence suppression pipe having one end connected to one of the plurality of branch sections; and a second turbulence suppression pipe having one end connected to one of the plurality of branch sections, wherein the other ends of the first turbulence suppression pipe and the second turbulence suppression pipe are connected to the subcooling heat exchanger.

2. The air conditioner according to claim 1, wherein the length of the first turbulence suppression pipe in the longitudinal direction is longer than 10 times the inner diameter of the first turbulence suppression pipe.

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