JPH09292166A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the intermittent flowing noise generated from an expansion valve which is one of elements to constitute the cycle of an air conditioner. SOLUTION: The inner sectional area A3 of a piping 6 to be connected to a connection pipe 13 of an expansion valve 4 is not more than the inner sectional area A1 of the connection pipe 13, and the inner sectional areas A4, A5, A6 of the piping 7 to be connected to a connection pipe 14 of the expansion valve 4 are not more than the inner sectional area A2 of the connection pipe 14. Thus, in a heat pump cycle capable of heating and cooling operation, the inner sectional areas of both pipings to be connected to the expansion valve 4 are not more than the inner sectional area of each connection pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle for a refrigerator and an air conditioner, and relates to noise reduction of an expansion valve.

[0002]

2. Description of the Related Art In Japanese Unexamined Patent Publication No. 57-129371 (hereinafter referred to as Document 1), an auxiliary decompression for giving a predetermined dryness to a refrigerant introduced into the main decompression means is provided above a throttle portion which is the main decompression means. Means are provided. As the auxiliary depressurizing means, an orifice, a multi-hole orifice, and a means for disturbing the flow of the refrigerant using a coil spring are disclosed.

Further, in Japanese Utility Model Laid-Open No. 60-69970 (reference 2), a variable orifice that changes the opening area by receiving the refrigerant pressure is provided between the outlet of the condenser and the orifice of the expansion valve. . As the shape of the variable orifice, there are disclosed a disk-shaped main body in which a throttle hole is formed in the central portion and a disk-shaped main body in which a fan-shaped or circular communication hole is formed around the central throttle hole. .

Further, in Japanese Utility Model Laid-Open No. 1-88278 (Reference 3), a throttle device is built in the inlet pipe joint and the outlet pipe joint of the expansion valve. Further, the expansion valve is provided with a bypass passage that connects the upstream side and the downstream side of the expansion valve throttle in order to balance the pressure when the compressor is stopped.

[0005]

Generally, in the refrigeration cycle, the high temperature and high pressure gas refrigerant discharged from the compressor radiates heat in the condenser and becomes a high temperature liquid refrigerant. This high-temperature liquid refrigerant flows into an expansion valve as a pressure reducing device, where it becomes a gas-liquid two-phase refrigerant having a temperature lower than room temperature. This vapor-liquid two-phase refrigerant absorbs heat during evaporation and evaporates to become a low-temperature gas refrigerant and returns to the compressor.

Air conditioners, which have recently become the mainstream in package air conditioners, room air conditioners, etc., are of a separate type and are separated into an outdoor unit and an indoor unit. At this time, an expansion valve, which is a decompression expansion device, is often installed in an indoor unit to improve the performance and function of the air conditioner.

As described above, the liquid refrigerant normally flows into the expansion valve. However, the operating conditions of the air conditioner such as the number of revolutions of the compressor, indoor and outdoor conditions such as the outside air temperature, and the outdoor unit and the indoor unit. When the length of the pipe connecting to the machine is long, the refrigerant may be in a gas-liquid two-phase state due to the pressure drop. Further, for example, in the case of a multi-air conditioner in which a plurality of indoor units are connected to one outdoor unit, the amount of refrigerant flowing in each indoor unit differs depending on the state of the indoor unit being operated, and the state of gas-liquid two-phase flow Often becomes. When the refrigerant in the gas-liquid two-phase state flows into the expansion valve, a loud noise (hereinafter referred to as flowing noise) is generated. In addition, this flow sound is generated in close relation to the flow pattern of the gas-liquid two-phase flow, so the volume of the sound is
As a strange noise, it impairs comfort. For example, when a slug flow or a floss flow in which air bubbles are intermittently present in the flow flows into the expansion valve, a flow sound is intermittently generated, which is a very offensive sound.

In Reference 1, since an orifice is provided as an auxiliary pressure reducing device on the upstream side of the main pressure reducing device, the flow downstream of the auxiliary pressure reducing device is improved and the flow noise generated in the main pressure reducing device is improved. Expected However, with respect to the auxiliary decompression device, this portion is a throttle, and it is considered that the situation is the same as that occurring in the main decompression device when there is no auxiliary decompression device. That is, it is conceivable that the auxiliary decompression device may generate a flowing sound.
Furthermore, when the gas-liquid two-phase flow is formed on the upstream side of the pressure reducing device due to operating conditions and indoor / outdoor temperature conditions, it is conceivable that a significant flow noise is generated from the auxiliary pressure reducing device.

Further, in Reference 2, since a variable orifice that changes the opening area by receiving the refrigerant pressure is provided between the outlet of the condenser and the orifice of the expansion valve, the flow downstream of the variable orifice is improved. , Improvement of flow noise from expansion valve is expected. However, as described above, since the flow on the upstream side of the variable orifice has not been improved, there is a concern that a flow noise will be generated from the variable orifice this time. Also,
As the shape of the variable orifice, there are a disk-shaped body with a throttle hole formed in the center and a shape with a fan-shaped or circular communication hole formed around the center throttle hole. Since there is a throttle hole in the portion, when the flow is a slag flow or a plug flow, bubbles may pass through the throttle hole at the center as it is, which may reduce the effect of improving the flow.

Further, in Reference 3, a throttle device is built in the inlet pipe joint and the outlet pipe joint of the expansion valve. Also in this case, as described above, the flow on the upstream side of the expansion device has not been improved, so that there is a concern that the expansion device may generate a flowing sound. Further, since the shape of the expansion device is the one in which a restriction hole is formed in the central portion, when the flow is a slag flow or a plug flow, bubbles pass through the central restriction hole as it is, and the effect of improving flow is obtained. There is also concern about reduction.
Further, this expansion valve is provided with a bypass passage connecting the upstream side and the downstream side of the expansion valve throttle in order to balance the pressure when the compressor is stopped. It cannot be used as an expansion valve.

Therefore, in the present invention, the air conditioner (heat pump cycle and refrigeration cycle) capable of reducing the flow noise intermittently generated from the expansion valve due to the refrigerant gas-liquid two-phase flow.
The purpose is to provide.

[0012]

Means for Solving the Problems The above-mentioned object is, as a cooling-only machine, a compressor for compressing a refrigerant, a first heat exchanger for exchanging heat between the compressed refrigerant and the outside air, and an expansion. The second that performs heat exchange between the refrigerant flowing through the valve and the inside air
In an air conditioner including a heat exchanger, at least the diameter of the pipe on the expansion valve side of the pipes between the first heat exchanger and the expansion valve is set to the diameter of the pipe between the compressor and the first heat exchanger. It is achieved by making it thinner.

Further, as an air conditioner capable of cooling and heating, the above-mentioned object is achieved through a compressor, a four-way valve connected to the compressor, a first heat exchanger connected to the four-way valve, and an expansion valve. An air conditioner that is connected to a first lever heat exchanger and is connected to the four-way valve, and that performs a cooling operation and a heating operation by switching the four-way valve. This is achieved by making the diameter of the pipe to be connected smaller than the diameter of the pipe to be connected to the compressor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. First, the cycle will be described with reference to FIG. This figure is a diagram showing a cycle of an air conditioner according to an embodiment of the present invention. The cycle is compressor 1,
The four-way valve 2, the first heat exchanger 3, the expansion valve 4, the diversion / merger 8 and the second heat exchanger 5 are connected to the pipes 7, 11a, 11b, 11
c, 11d, and branch pipes 9a, 9b, respectively. In this embodiment, the shape of the pipe 7 between the expansion valve and the flow divider / combiner is a U-shaped pipe having two bent portions. Also, a resistor 19 and a resistor 21 are installed at the bent portion outlets closest to the expansion valve. During the cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is cooled by the air sent by the fan 10a in the first heat exchanger 3 to become a high-pressure liquid refrigerant. This refrigerant flows into the expansion valve 4, becomes a refrigerant in a gas-liquid two-phase state having a temperature lower than the indoor air temperature, and the fan 10 in the second heat exchanger 5 is used.
The heat is taken from the indoor air sent in b to evaporate and return to the compressor 1 again. Further, during the heating operation, the circulation direction of the refrigerant is reversed by switching the four-way valve 2. That is, the refrigerant flows in the order of the compressor 1, the four-way valve 2, the second heat exchanger 5, the expansion valve 4, the first heat exchanger 3, and the four-way valve 2 and returns to the compressor 1 again. At this time, due to the operating conditions, the first heat exchanger 3 cannot fully condense during the cooling operation, and the second heat exchanger 5 during the heating operation.
In some cases, the gas does not completely condense and flows out in a gas-liquid two-phase state. In this case, since the refrigerant flows into the expansion valve 4 in a gas-liquid two-phase flow state, an intermittent flow noise is generated from the expansion valve 4. This intermittently generated flow sound is related to the flow mode of the refrigerant, and the expansion valve 4 alternates between the gas-liquid two-phase refrigerant and the liquid refrigerant, or alternates between the gas-liquid two-phase state and the liquid refrigerant state. It is caused by flowing into.

A portion 12 surrounded by a broken line in the drawing is a portion devised to reduce the refrigerant flow noise, and its embodiment is shown in FIGS. 1 to 7.

FIG. 1 is a diagram showing a setting example of piping connected to an expansion valve which is an embodiment of the present invention. The part in the chain line in the figure is the expansion valve 4. The expansion valve 4 is the valve body 1
6, valve rod 17, motor 1 for driving the valve rod 17 up and down
5 and joint pipe 1 attached to both inlets of the valve body
3 and a joint pipe 14. In FIG.
During the cooling operation, the refrigerant flows into the expansion valve 4 from the pipe 6 side. Further, during the heating operation, it flows into the expansion valve 4 from the pipe 7 side. Depending on the operating conditions, the gas may flow into the expansion valve 4 in a gas-liquid two-phase state during both the cooling operation and the heating operation. At this time, intermittent flow noise is generated from the expansion valve 4. In order to reduce this flow noise, in one embodiment of the present invention, the inner cross-sectional area of the pipe connected to the expansion valve 4 is set as follows. Here, the inner cross-sectional area of the pipe is a cross-sectional area based on the inner diameter. Inner cross-sectional areas A1, A2, A in FIG.
3, A4, A5, A6, and A7 are respective portions, which schematically show the size of the inner cross-sectional area in the plane orthogonal to the pipe axis. That is, assuming a cooling operation, the inner cross-sectional area A3 of the pipe 6 connected to the joint pipe 13 of the expansion valve 4 is the inner cross-sectional area A1 of the joint pipe 13 (the pipe from the first heat exchanger 3 not shown). Below. Further, assuming heating operation, the inner cross-sectional area A of the pipe 7 connected to the joint pipe 14 of the expansion valve 4 is
4, A5, A6 to the joint pipe 14 (compressor 2 not shown
To the second heat exchanger 5), the inner cross-sectional area A2 or less. Therefore, in a heat pump cycle capable of cooling and heating operation, the inner cross-sectional areas of both pipes connected to the expansion valve 4 are equal to or less than the inner cross-sectional area of the joint pipe. As a result, when the joint pipe and the connecting pipe have the same inner cross-sectional area, the refrigerant flow flowing into the expansion valve 4 does not cause a change in the shape of the pipe so that pressure pulsation does not increase and the refrigerant expands as a stable flow. Valve 4
Can be flowed into.

However, when the expansion valve and the pipes are mounted on the air conditioner, it is impossible to connect all the pipes in a straight line. Therefore, as shown in FIG. 1, a bent portion of the pipe is always generated. To do. At this time, even if the joint pipe of the expansion valve 4 and the connecting pipe have the same inner cross-sectional area, the flow state of the refrigerant flow flowing in the bent portion of the pipe changes, and particularly in the case of gas-liquid two-phase flow, the flow mode is changed. The vapor phase tends to stay in the change and bend portions to form large bubbles, and the liquid refrigerant pushes them out to cause pressure pulsation and flow rate fluctuations. If the refrigerant flow having these flow fluctuations directly flows into the throttle formed by the gap between the valve rod 17 and the valve body 16 of the expansion valve 4, an intermittent flow noise is generated.

Therefore, the inner cross-sectional area of the pipe to be connected is set smaller than the inner cross-sectional area of the joint pipe of the expansion valve 4. That is,
The inner sectional area A3 of the connecting pipe 6 is set smaller than the inner sectional area A1 of the joint pipe, and the inner sectional areas A4, A5 and A6 of the connecting pipe 7 are set smaller than the inner sectional area A4 of the joint pipe 14.

The cause of the flow noise is the change in pressure of the fluid passing through the expansion valve, and the flow mode with the largest change in pressure is a liquid containing large shell-shaped bubbles and small bubbles that fills the pipe section. It is a slug flow or plug flow, which is a flow in which parts alternate. When this flow passes through the expansion valve,
Since the gas phase portion having a large change in pressure and the liquid phase portion having a small change pass alternately, an annoying intermittent noise is generated.
In the present embodiment, the piping in the indoor unit (or,
Since the diameter of the indoor piping) is made smaller than the diameter of the piping from the outdoor unit to the indoor, even if it enters the room in a gas-liquid two-phase flow state, the internal cross-sectional area of the piping is reduced. The flow velocity of the refrigerant flow is increased, and the flow such as the slug flow and the plug flow described above is changed into a flow mode of an annular flow in which a liquid film is present on the pipe wall and a vapor phase flow exists near the center of the pipe cross section. Therefore, in the vicinity of the orifice of the expansion valve, fine air bubbles are sufficiently mixed in the liquid and pass through the expansion valve in that state. Therefore, unlike a slug flow in which large bubbles and a liquid phase pass alternately, the gas phase and the liquid phase are continuous with each other, and the pressure change is small, so that intermittent flow noise can be reduced. . Further, since the frequency of the refrigerant sound passing through the expansion valve becomes high, by providing a sound absorbing material or the like around the expansion valve, it is possible to reduce noise rather than intermittent sound at low frequency.

Also, as shown in FIG. 1, when the pipe diameters of the joint pipes 13 and 14 of the expansion valve 4 are larger than those of the pipes 6 and 7, the refrigerant is connected from the pipes 6 or 7 in a flow mode of an annular flow. When flowing into the pipe 13 or 14, it becomes a jet flow and flows into the joint pipe 13 or 14. At this time, again, the refrigerant in which the liquid and the air bubbles are sufficiently mixed passes through the expansion valve. Then, since the fluctuation of the refrigerant pressure becomes small when passing through, it is possible to prevent the generation of abnormal noise.

By the way, in the above-mentioned embodiment, the pipes between the first heat exchanger 3 and the second heat exchanger 5 which sandwich the expansion valve 4 and in which the pipe diameters of the pipes 6 and 7 in the indoor part are reduced. However, since it is possible to prevent the generation of annoying noise by setting the flow mode of the refrigerant in the pipe from the heat exchanger to the expansion valve to the flow mode of the annular flow, without sticking to the indoors or outdoors, The pipe diameter between the first heat exchanger 3 and the second heat exchanger 5 sandwiching the expansion valve 4 is made smaller than the pipe diameter between the first heat exchanger 3 and the second heat exchanger 5 sandwiching the compressor. Even if the same effect is expected. The two-phase flow originally does not flow in the pipe between the first heat exchanger 3 and the second heat exchanger 5 that sandwich the expansion valve 4, and even if the two-phase flow occurs for some reason, the flow velocity in this part Is increased, the flow does not shift to an intermittent flow such as a slag flow that causes abnormal noise.
In this case, there is an effect that a connecting portion for indoor and outdoor piping is not required.

Next, the case of heating operation will be described in detail. The refrigerant from the second heat exchanger is divided into branch pipes 9a and 9b.
Through the branching and merging unit 8 to flow into the connecting pipe 7 and flow into the expansion valve 4. The diversion / merging unit 8 has an orifice 18 for improving the diversion of the refrigerant flow during the cooling operation.
(Or diaphragm) is provided. This orifice 18
By making the inner cross-sectional area A7 of the refrigerant passage 23 smaller than the inner cross-sectional areas A6, A5, and A4 of the connection pipe 7, it becomes possible to further promote the stabilization of the flow. During the heating operation, as described above, the refrigerant flows coming from the branch pipes 9a and 9b collide with each other and mix in the space 34 of the diversion / merging unit 8,
Very disturbed. When the refrigerant flow in the turbulent state flows into the connection pipe 7, it is necessary to increase the length of the pipe depending on the situation only by the effect of increasing the flow velocity. However, in an actual air conditioner, the space that can be used for arranging the pipes is generally very small, and it is not possible to take the necessary pipe length. Therefore, the refrigerant passage 2 of the orifice 18
3 is the inner cross-sectional area A7 of the refrigerant passage 7
By making it smaller than A4, it is made to flow from the orifice 18 into the connection pipe 7 in a jet state, and the flow is stabilized and gas and liquid are uniformly mixed. As a result, the length of the connecting pipe can be minimized and the flow noise can be reduced.

FIG. 2 is a diagram showing a case in which a resistor is provided in the pipe connected to the expansion valve according to the embodiment of the present invention.

As described in the previous embodiment, in actual air conditioners, the pipe installation space is very narrow, so the radius of curvature of the bent portion may be very small. When the radius of curvature is small, especially in the case of gas-liquid two-phase flow, the gas phase tends to stay in the bent portion, which becomes a factor that obstructs the flow in the bent portion, and the liquid refrigerant pushes out the gas phase, resulting in a large pressure. Pulsations and flow rate fluctuations are likely to occur. In particular, it becomes remarkable in the transition from horizontal pipe to vertical pipe, or from vertical pipe to horizontal pipe, and in terms of flow, from horizontal flow to vertical upward flow. Therefore, it is desirable to have a large radius of curvature or to lengthen the straight pipe after passing through the bent portion, but this is often impossible in terms of installation.
Therefore, as shown in FIG. 2, a resistor is provided at the outlet of the curved portion in the flow direction of the refrigerant to correct the flow turbulence generated at the curved portion. That is, in the case of the present embodiment, during the cooling operation, the gas flows into the expansion valve 4 from the pipe 11c side. Therefore, the resistor 19 is installed on the downstream side of the bent portion 35, that is, between the bent portion 35 and the joint pipe 13. Similarly, during the heating operation, it flows into the expansion valve 4 from the side of the flow divider / combiner 8. Therefore,
The resistor 21 is provided between the bent portion 36 and the joint pipe 14. At this time, it is effective to select the target bent portion that is closest to the inflowing expansion valve.

The resistor may be installed at the entrance of the bent portion. However, at the bend,
Since the flow is always turbulent, it is less effective than when installed at the exit of the bend.

A perforated plate or the like is effective as the resistor.
Even if the total area of each hole of the perforated plate is about the same as the inner cross-sectional area of the pipe, the perforation makes the refrigerant flow out of one hole into a jet flow, and the turbulent flow also passes through the resistor. The flow can be stabilized. Further, since the flow becomes porous, the wetting edge length becomes long and the resistance increases, and this effect also stabilizes the flow.

3 to 7 show one embodiment of the shape of the resistor.

FIG. 3 is a view showing a cross section parallel to the piping axis of the resistor. The refrigerant passages are 25a and 25b. The feature is that there is no hole through which the refrigerant passes in the pipe axis, that is, in the center. This is because, for example, in the case of a vertically rising flow, the bubbles (gas phase) are gathered in the central part of the pipe, and if there is a hole in the central part, the bubbles pass through as they are, and the flow cannot be improved.

FIG. 4 is a view showing a cross section perpendicular to the pipe axis of the resistor. The resistor 26 has eight holes provided concentrically. The refrigerant passages are 27a to 27h. There is no hole in the center. FIG. 5 shows a resistor 28 having five holes.
It is. When the open areas of the 8-hole resistor 26 and the 5-hole resistor 28 in FIG. 4 are the same, the wetting edge length is longer in the case of 8 holes, so that the resistor 26 is larger than the resistor 28. However, the flow resistance is large. 6 and 7 show a case where a fan-shaped hole is used instead of the circular hole. Also in this case, there is no hole in the center.

In the air conditioner according to one embodiment of the present invention described with reference to FIGS. 1 to 8, when a single refrigerant is used, mixed refrigerant in which various refrigerants are mixed and various kinds of refrigerants having different boiling points are used. Even when using a non-azeotropic mixed refrigerant in which the refrigerant is mixed, the flow pattern of the gas-liquid two-phase refrigerant flow that causes the intermittent flow noise generated from the expansion valve does not change, and the present invention The effect of improving the flow by is similarly obtained.

In the air conditioner described above, the compressor is
It may be a constant speed machine or an overspeed machine using an inverter. In the air conditioner described above, the cycle may be a heat pump cycle capable of cooling / heating operation or a refrigeration cycle capable of either cooling or heating operation. According to the embodiment of the present invention described above, in the heat pump cycle and the refrigeration cycle, the refrigerant state of the gas-liquid two-phase flow cannot be completely condensed in the first heat exchanger or the second heat exchanger used as the condenser depending on the operating conditions. Even in the case of, the present invention can reduce the pressure pulsation and the flow rate fluctuation by promoting the homogenization of gas-liquid in the actual air-conditioner piping shape, and stabilize the flow, so that the expansion valve can be intermittently operated. It is possible to reduce the flow noise generated in the. As a result, noise reduction of the air conditioner is promoted, and comfort can be improved.

[0032]

According to the air conditioner of the present invention, in the case of gas-liquid two-phase flow, the flow velocity of the refrigerant flowing in the pipe is increased to promote the stabilization of the gas-liquid and stabilize it. Since the flow velocity increases, for example, a gas-liquid discontinuous flow pattern such as a slag flow or a floss flow shifts to a continuous gas-liquid annular flow. In addition, a resistor is installed at the outlet at the bend closest to the inlet of the expansion valve, and the flow turbulent at the bend is corrected by the resistor. The effect of can be maintained. As a result, the expansion valve can reduce the flow noise caused by the gas-liquid two-phase flow generated from the pipe, and the quietness can be maintained and the comfort can be improved.

[Brief description of drawings]

FIG. 1 shows an air conditioner according to an embodiment of the present invention in which an inner cross-sectional area of a pipe connected to an expansion valve and an inner cross-sectional area of an orifice in a shunt junction are smaller than an inner cross-sectional area of a joint pipe of the expansion valve. Partial view.

FIG. 2 is a partial view of an air conditioner according to an embodiment of the present invention in which a resistor is provided at the outlet of the bent portion of the pipe.

FIG. 3 is a sectional view of a resistor according to an embodiment of the present invention.

FIG. 4 is a diagram of a circular 8-hole resistor according to an embodiment of the present invention.

FIG. 5 is a diagram of a circular five-hole resistor according to an embodiment of the present invention.

FIG. 6 is a diagram of a fan-shaped two-hole resistor according to an embodiment of the present invention.

FIG. 7 is a diagram of a fan-shaped 4-hole resistor according to an embodiment of the present invention.

FIG. 8 is a cycle diagram of the air conditioner according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four-way valve, 3 ... 1st heat exchanger, 4 ... Expansion valve, 5 ... 2nd heat exchanger, 6, 7 ... Connection piping, 8 ... Diverging / combining machine, 9a, 9b ... Branch pipe 10a, 10b ... fans,
11a, 11b, 11c, 11d ... Piping, 12 ... Expansion valve peripheral part, 13, 14 ... Joint pipe, 15 ... Motor,
16 ... Valve body, 17 ... Valve rod, 18 ... Orifice (throttle),
19, 21, 24, 26, 28, 30, 32 ... Resistors,
20a, 20b, 22a, 22b, 25a, 25b, 2
7a, 27b, 27c, 27d, 27e, 27f, 27
g, 27h, 29a, 29b, 29c, 29d, 29
e, 31a, 31b, 33a, 33b, 33c, 33d
... Refrigerant passage, 23 ... Intra-orifice refrigerant passage, 34 ... Combined mixing space, 35, 36 ... Pipe bend, A1, A2 ... Joint pipe inner cross-sectional area, A3, A4, A5, A6 ... Connection pipe inner cross-sectional area, A7 ... Internal cross-sectional area of the orifice (throttle).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Sano 390 Muramatsu, Shimizu-shi, Shizuoka Hitachi Air Conditioning Systems Division (72) Inventor Atsushi Kobayashi 390 Muramatsu, Shimizu-shi, Hitachi Hitachi Shimizu Engineering Co., Ltd. In-house (72) Hideki Okuzono, 390 Muramatsu, Shimizu City, Shizuoka Prefecture, Hitachi, Ltd., Air Conditioning Systems Division, Hitachi, Ltd. (72) Kazuyuki Kuroyanagi, 390, Muramatsu, Shimizu City, Shizuoka, Hitachi, Ltd. ) Masamichi Hanada Inventor Masamichi 390 Muramatsu, Shimizu City, Shizuoka Prefecture Hitachi Ltd. Air Conditioning Systems Division

Claims (6)

[Claims] Claim: What is claimed is: 1. A compressor for compressing a refrigerant, a first heat exchanger for exchanging heat between the compressed refrigerant and the outside air, and a heat flow between the refrigerant flowing through an expansion valve and the inside air. In an air conditioner provided with a second heat exchanger for exchanging, of the pipes between the first heat exchanger and the expansion valve, at least the diameter of the pipe on the expansion valve side is set to the compressor and the first heat exchanger. An air conditioner that is thinner than the diameter of the pipe between them. 2. The air conditioner according to claim 1, wherein a resistance is provided at the outlet of the bent portion of the pipe connected to the expansion valve, which is closest to the expansion valve. 3. The air conditioner according to claim 2, wherein the resistor is provided with a hole through which the refrigerant passes in an outer peripheral portion of a pipe cross section. 4. A compressor, a four-way valve connected to this compressor, a first heat exchanger connected to this four-way valve, and a first heat exchanger connected via an expansion valve, An air conditioner that includes a second heat exchanger connected to a four-way valve, and performs a cooling operation and a heating operation by switching the four-way valve, in which a diameter of a pipe connected to the expansion valve is connected to the compressor. An air conditioner that is thinner than the diameter of the pipe to be used. 5. The air conditioner according to claim 4, wherein a resistance is provided at the outlet of the bent portion of the pipe connected to the expansion valve closest to the expansion valve. 6. The air conditioner according to claim 5, wherein the resistor is provided with a hole through which the refrigerant passes in an outer peripheral portion of a pipe cross section.