EP2058609A1

EP2058609A1 - Air conditioner

Info

Publication number: EP2058609A1
Application number: EP07792160A
Authority: EP
Inventors: Satoshi Ishikawa; Masanori c/o Kanaoka Factory Sakai Plant MASUDA; Masahide c/o Shiga Plant HIGUCHI
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2006-08-11
Filing date: 2007-08-08
Publication date: 2009-05-13
Also published as: AU2007282504B2; JP2008045778A; CN101501420A; US20100175409A1; CN101501420B; KR20090034944A; AU2007282504A1; WO2008018489A1

Abstract

An air conditioning apparatus is provided whereby the pressure pulsation generated by a compressor can be entirely reduced both during cooling and during heating, and a muffler can be shared. The air conditioning apparatus (1) is an air conditioning apparatus including a refrigerant circuit (7). The refrigerant circuit (7) is configured so that a compressor (2) for compressing a refrigerant, an indoor heat exchanger (3), an outdoor heat exchanger (4), and a four-way switch valve (5) are connected via a refrigerant pipe (6). The four-way switch valve (5) switches the flow of refrigerant compressed by the compressor (2) to either the indoor heat exchanger (3) or the outdoor heat exchanger (4). The air conditioning apparatus (1) further includes a pressure pulsation reducing component (8). The pressure pulsation reducing component (8) is provided between the four-way switch valve (5) and the indoor heat exchanger (3). The pressure pulsation reducing component (8) reduces pressure pulsation inside the refrigerant circuit (7). The pressure pulsation is generated by the compressor (2).

Description

TECHNICAL FIELD

The present invention relates to an air conditioning apparatus provided with a refrigerant circuit that includes a compressor.

BACKGROUND ART

Conventional refrigerant circuits have problems in that pressure pulsation generated by a compressor is propagated through a refrigerant pipe into an indoor refrigerant pipe near the indoor units, and vibration and/or abnormal noise is generated from the indoor refrigerant pipe and the indoor units. An air conditioning apparatus has therefore been disclosed in Patent Document 1, in which a single muffler is provided between the compressor and a four-way switch valve in order to suppress the propagation of pressure pulsation to the indoor refrigerant pipe.
<Patent Document 1> Japanese Laid-open Patent Publication No. 9-250831

DISCLOSURE OF THE INVENTION

PROBLEMS THE INVENTION IS INTENDED TO SOLVE

In the case of the air conditioning apparatus disclosed in Patent Document 1, the pressure pulsation can be reduced by the muffler when the pulsation generated by the compressor is directed toward the indoor units via the four-way switch valve (i.e., in the case of suction pulsation during heating, and exhaust pulsation during cooling). However, when the pulsation generated by the compressor is directed toward the indoor units and not through the four-way switch valve (i.e., in the case of exhaust pulsation during heating, and suction pulsation during cooling), the pressure pulsations do not pass through the muffler, and it is therefore impossible both during cooling and heating to entirely reduce the pressure pulsation generated by the compressor through the use of the muffler before the pressure pulsation reaches the indoor refrigerant pipe near the indoor units.
Further, providing a muffler to both the suction side and the exhaust side of the compressor has a problem in that it increases the number of components and the manufacturing cost.
An object of the present invention is to provide an air conditioning apparatus wherein the pressure pulsation generated by the compressor can be entirely reduced during cooling as well as during heating and it is capable of muffler sharing.

MEANS FOR SOLVING THESE PROBLEMS

An air conditioning apparatus according to a first aspect of the present invention is an air conditioning apparatus comprising a refrigerant circuit. The refrigerant circuit is configured so that a compressor for compressing a refrigerant, an indoor heat exchanger, an outdoor heat exchanger, and a four-way switch valve are connected via a refrigerant pipe. The four-way switch valve switches the flow of refrigerant compressed by the compressor to either the indoor heat exchanger or the outdoor heat exchanger. The air conditioning apparatus further comprises a pressure pulsation reducing component. The pressure pulsation reducing component is provided between the four-way switch valve and the indoor heat exchanger. The pressure pulsation reducing component reduces pressure pulsation inside the refrigerant circuit. The pressure pulsation is generated by the compressor.
In this configuration, since the pressure pulsation reducing component is provided between the four-way switch valve and the indoor heat exchanger, the pressure pulsation generated by the compressor can be entirely reduced before reaching the indoor refrigerant pipe both during cooling and during heating in the case of an air conditioning apparatus that switches between cooling and heating. Further, a muffler used for reducing pressure pulsations can be shared, and the number of components can be reduced.
An air conditioning apparatus according to a second aspect of the present invention is the air conditioning apparatus of the first aspect, wherein the pressure pulsation reducing component is provided within an outdoor unit. The compressor and the outdoor heat exchanger are housed in the outdoor unit.
Since the pressure pulsation reducing component is provided within the outdoor unit in which the compressor and the outdoor heat exchanger are housed, the pressure pulsation reducing component is easily installed and maintained. Moreover, since the pressure pulsation reducing component is installed at the position near the compressor, which is the source of the pressure pulsation, within the refrigerant circuit, the pressure pulsation reducing effects thereof are significant.
An air conditioning apparatus according to a third aspect of the present invention is the air conditioning apparatus of the first or second aspect, wherein the refrigerant is CO₂.
In this configuration, CO₂ is used as the refrigerant, and pressure pulsations are more significant compared with other refrigerants, but pulsations can be reduced both during cooling and during heating by the pressure pulsation reducing component provided between the four-way switch valve and the indoor heat exchanger. A CO₂ refrigerant has low global warming potential and enables products that are environmentally friendly. The CO₂ refrigerant also has high refrigeration capacity per unit volume, and a cylinder for achieving the same capacity as other refrigerants can be reduced in size, and the compressor can also be reduced in size.
An air conditioning apparatus according to a fourth aspect of the present invention is the air conditioning apparatus of any of the first through third aspects, wherein the pressure pulsation reducing component is a vessel having a muffler function.
In this configuration, since the pressure pulsation reducing component is a vessel having a muffler function, not only can pressure pulsations be reduced, but liquid-vapor separation of the refrigerant is also possible inside the vessel.
An air conditioning apparatus according to a fifth aspect of the present invention is the air conditioning apparatus of any of the first through fourth aspects, wherein the pressure pulsation reducing component is one component selected from the group consisting of an expansion muffler, a π-type filter, a side branch muffler, a Helmholtz muffler, and an interference muffler.
In this configuration, because the pressure pulsation reducing component is one component selected from the group consisting of an expansion muffler, a π-type filter, a side branch muffler, a Helmholtz muffler, and an interference muffler, pressure pulsation can be effectively reduced using these conventionally known mufflers.

EFFECT OF THE INVENTION

According to the first aspect, the pressure pulsation generated by the compressor can be entirely reduced before reaching the indoor refrigerant pipe both during cooling and during heating. A muffler used for reducing pressure pulsations can also be shared, and the number of components can be reduced.
According to the second aspect, the pressure pulsation reducing component is easily installed and maintained, and the pressure pulsation reducing effects of the pressure pulsation reducing component are significant.
According to the third aspect, although pressure pulsations are more significant compared with other refrigerants, pulsations can be reduced both during cooling and during heating by the pressure pulsation reducing component provided between the four-way switch valve and the indoor heat exchanger. A CO₂ refrigerant has low global warming potential and enables products that are environmentally friendly. A CO₂ refrigerant also has high refrigeration capacity per unit volume, and a cylinder for achieving the same capacity as other refrigerants can be reduced in size, and the compressor can also be reduced in size.
According to the fourth aspect, not only can pressure pulsations be reduced, but liquid-vapor separation of the refrigerant is also possible inside the vessel.
According to the fifth aspect, pressure pulsation can be effectively reduced using a conventionally known muffler.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG 1 is a schematic diagram showing an air conditioning apparatus according to an embodiment of the present invention.
FIG 2 is a schematic diagram showing an expansion muffler as a specific example of a pressure pulsation reducing component of FIG. 1.
FIG. 3 is a schematic diagram showing a π-type filter as a specific example of the pressure pulsation reducing component of FIG. 1.
FIG. 4 is a schematic diagram showing a side branch muffler as a specific example of the pressure pulsation reducing component of FIG. 1.
FIG 5 is a schematic diagram showing a Helmholtz muffler as a specific example of the pressure pulsation reducing component of FIG. 1.
FIG. 6 is a schematic diagram showing an interference muffler as a specific example of the pressure pulsation reducing component of FIG. 1.

KEY

1: air conditioning apparatus
2: compressor
3: indoor heat exchanger
4: outdoor heat exchanger
5: four-way switch valve
6: refrigerant pipe
7: refrigerant circuit
8: pressure pulsation reducing component
9: outdoor unit

BEST MODE FOR CARRYING OUT THE INVENTION

An air conditioning apparatus 1 shown in FIG. 1 is capable of both a cooling operation and a heating operation, and is provided with a refrigerant circuit 7 configured so that a compressor 2 for compressing a CO₂ refrigerant; an indoor heat exchanger 3; an outdoor heat exchanger 4; a four-way switch valve 5 for switching the flow of refrigerant compressed by the compressor 2 to either the indoor heat exchanger 3 or outdoor heat exchanger 4; and an electromagnetic expansion valve 10 are connected via a refrigerant pipe 6. The air conditioning apparatus 1 is further provided with a pressure pulsation reducing component 8 for reducing pressure pulsation that is generated by the compressor 2 within the refrigerant circuit 7.
The pressure pulsation reducing component 8 is provided between the four-way switch valve 5 and the indoor heat exchanger 3. Therefore, the pressure pulsation generated by the compressor can be entirely reduced both during cooling and during heating in the case of the air conditioning apparatus 1 that switches between cooling and heating. The muffler used for reducing pressure pulsations can also be shared, and the number of components can be reduced.
The pressure pulsation reducing component 8 is provided within an outdoor unit 9 in which the compressor 2 and outdoor heat exchanger 4 are housed.
In the air conditioning apparatus 1, CO₂ is used as the refrigerant. The pressure pulsations of a CO₂ refrigerant are more significant than the pressure pulsations of other refrigerants, but pulsations can be reduced both during cooling and during heating by the pressure pulsation reducing component 8 provided between the four-way switch valve 5 and the indoor heat exchanger 3.
The pressure pulsation reducing component 8 is specifically one component selected from the group consisting of an expansion muffler, a π-type filter, a side branch muffler, a Helmholtz muffler, and an interference muffler.
As shown in FIG. 2, an expansion muffler 21 has an expansion portion 21a and straight pipe portions 21b connected on both sides thereof. The cross-sectional area S2 of the expansion portion 21a is larger than the cross-sectional area S1 of the straight pipe portions 21b.
The value of the transmission loss TL of the expansion muffler 21 is indicated by the equation below. $TL = 10 \times \log (1 + 1 / 4 \times {(m - 1 / m)}^{2} \times \sin^{2} (k \times L 1))$
In the equation, L1 is the length of the expansion portion 21a, m = S2/S1, and k = 2πf/c, wherein c is the speed of sound.
As shown in FIG. 3, a π-type filter 22 has a first expansion portion 22a, a second expansion portion 22b, a connecting pipe portion 22c, a first straight pipe portion 22d, and a second straight pipe portion 22e. The connecting pipe portion 22c connects the first expansion portion 22a and the second expansion portion 22b. The first straight pipe portion 22d is connected on the opposite side from the connecting pipe portion 22c in the first expansion portion 22a. The second straight pipe portion 22e is connected on the opposite side from the connecting pipe portion 22c in the second expansion portion 22b. Each of the cross-sectional areas of the first expansion portion 22a and the second expansion portion 22b are larger than cross-sectional areas S3, S4 of the connecting pipe portion 22c, and the first straight pipe portion 22d and second straight pipe portion 22e, respectively.
The value of the transmission loss TL of the π-type filter 22 is as shown below. (Note that L2 is the length of the connecting pipe portion 22c, V1 is the volume of the first expansion portion 22a, V2 is the volume of the second expansion portion 22b, S3 is the cross-sectional area of each of the first straight pipe portion 22d and the second straight pipe portion 22e, and S4 is the cross-sectional area of the connecting pipe portion 22c.) $TL = 10 \times \log (σ^{2})$
In the equation, σ = V² × ω³ × L2/(S3 × S4 × c³), wherein c is the speed of sound.
As shown in FIG. 4, a side branch muffler 23 has a branch portion 23a and a straight pipe portion 23b. The branch portion 23a branches at a right angle from the straight pipe portion 23b.
The frequency f of the side branch muffler 23 is as shown below. $f = c / (4 \times L 3)$
In the equation, L3 is the length of the branch portion 23a, and c is the speed of sound.
As shown in FIG. 5, a Helmholtz muffler 24 has an expansion portion 24a, a connecting pipe portion 24b, and a straight pipe portion 24c. The connecting pipe portion 24b branches at a right angle from the straight pipe portion 24c. The connecting pipe portion 24b connects the expansion portion 24a and the straight pipe portion 24c. The cross-sectional area of the expansion portion 24a is larger than the cross-sectional area of each of the connecting pipe portion 24b and the straight pipe portion 24c.
The frequency f of the Helmholtz muffler 24 is as shown below. $f = c / 2 π \times \sqrt (S 5 / (V 3 \times L 4))$
In the equation, V3 is the volume of the expansion portion 24a, S5 is the cross-sectional area of the connecting pipe portion 24b, L4 is the length of the connecting pipe portion 24b, and c is the speed of sound.
As shown in FIG. 6, an interference muffler 25 has a curved pipe portion 25a that extends in an arch, and a straight pipe portion 25b. Both ends of the curved pipe portion 25a are connected to the straight pipe portion 25b.
The half wavelength λ/2 of the interference muffler 25 is in the relationship as shown below: $λ / 2 = L 5 - L 6$
In the equation, L5 is the pipe length of the curved pipe portion 25a, and L6 is the pipe length of the straight pipe portion 25b.

(1)

In the air conditioning apparatus 1 according to the embodiment, since the pressure pulsation reducing component 8 is provided between the four-way switch valve 5 and the indoor heat exchanger 3, the pressure pulsation generated by the compressor 2 can be entirely reduced before reaching the indoor refrigerant pipe both during cooling and during heating in the case of the air conditioning apparatus 1 that switches between cooling and heating. The muffler used for reducing pressure pulsations can also be shared, thereby the number of components can be reduced.
Particularly in a ceiling-mounted indoor unit or room air conditioner, the length of the refrigerant pipe is relatively small, and the indoor refrigerant pipe tends to vibrate and readily generate noise, but pressure pulsation can be effectively reduced in the air conditioning apparatus 1 of the present embodiment in such a case.

(2)

In the air conditioning apparatus 1 of the present embodiment, since the pressure pulsation reducing component 8 is provided within an outdoor unit 9 in which the compressor 2 and the outdoor heat exchanger 4 are housed, the pressure pulsation reducing component 8 is easily installed and maintained. Further, since the pressure pulsation reducing component 8 is installed at a position near the compressor 2, which is the source of the pressure pulsation, within the refrigerant circuit 7, the pressure pulsation reducing effects thereof are significant.

(3)

In the air conditioning apparatus 1 of the present invention, CO₂ is used as the refrigerant, and although pressure pulsations are more significant compared with other refrigerants, pulsations can be reduced both during cooling and during heating by the pressure pulsation reducing component 8 provided between the four-way switch valve 5 and the indoor heat exchanger 3. A CO₂ refrigerant has low global warming potential and enables products that are environmentally friendly. A CO₂ refrigerant also has high refrigeration capacity per unit volume, and a cylinder for achieving the same capacity as other refrigerants can be reduced in size, and the compressor can also be reduced in size.

(4)

In the air conditioning apparatus 1 of the present embodiment, the pressure pulsation reducing component 8 is one component selected from the group that consists of an expansion muffler, a π-type filter, a side-branch muffler, a Helmholtz muffler, and an interference muffler; and pressure pulsation can therefore be effectively reduced using these conventionally known mufflers.

The pressure pulsation reducing component 8 may also be a component that has a function in addition to a muffler function. For example, the pressure pulsation reducing component 8 may be a vessel having a muffler function. In this case, not only can pressure pulsations be reduced, but liquid-vapor separation of the refrigerant is also possible inside the vessel.
The vessel having a muffler function may also be one component selected from the above-described group that consists of an expansion muffler, a π-type filter, a side-branch muffler, a Helmholtz muffler, and an interference muffler.

INDUSTRIAL APPLICABILITY

The present invention can be widely used in air conditioning apparatus provided with a refrigerant circuit that includes a compressor.

Claims

An air conditioning apparatus (1) including a refrigerant circuit (7) configured so that a compressor (2) for compressing a refrigerant, an indoor heat exchanger (3), an outdoor heat exchanger (4), and a four-way switch valve (5) for switching the flow of refrigerant compressed by the compressor (2) to either the indoor heat exchanger (3) or the outdoor heat exchanger (4) are connected via a refrigerant pipe (6), the air conditioning apparatus comprising:
a pressure pulsation reducing component (8) provided between the four-way switch valve (5) and the indoor heat exchanger (3) and configured to reduce pressure pulsation inside the refrigerant circuit (7) generated by the compressor (2).
The air conditioning apparatus (1) according to claim 1, wherein
the pressure pulsation reducing component (8) is provided within an outdoor unit (9) configured to house the compressor (2) and the outdoor heat exchanger (4) therein.
The air conditioning apparatus (1) according to claim 1 or 2, wherein the refrigerant is CO₂.
The air conditioning apparatus (1) according to any of claims 1 through 3, wherein
the pressure pulsation reducing component (8) is a vessel having a muffler function.
The air conditioning apparatus (1) according to any of claims 1 through 4, wherein
the pressure pulsation reducing component (8) is one component selected from the group consisting of an expansion muffler, a π-type filter, a side branch muffler, a Helmholtz muffler, and an interference muffler.