KR20040094338A - A refrigerator - Google Patents

Abstract

The present invention relates to an air conditioner, and the present invention relates to an air conditioner capable of preventing a bypass of a refrigerant from a compressor to a low pressure gas pipe during the operation of a heating main body in a three-tube air conditioner. The air conditioner includes an outdoor unit 21, an indoor unit 28, and a high pressure gas pipe 32, a low pressure gas pipe 33, and a high pressure liquid pipe 34 connected between the outdoor unit 21 and the air conditioner 31 therebetween. The high pressure liquid pipe 34 and the high pressure gas pipe 32 through the compressor 22, the outdoor heat exchanger 24, and the expansion valve 25 to the first to fourth ports 23A to 23D of the four-way valve 23 The low pressure gas pipe 33 is connected to each other, and the high pressure branch pipe 38 is branched between the second port 23B and the high pressure liquid pipe 34 to be connected to the high pressure gas pipe 32. The two ports 23A and 23B are connected to each other, and the third and fourth ports 23C and 23D are connected to each other. The mutual pipes 23A and 23C and the second and fourth ports 23B and 23D are connected to each other.

Description

Air Conditioning Equipment {A refrigerator}

The present invention includes a plurality of indoor units, a plurality of the air conditioning operation of the cooling main operation and the rest of the heating operation, the contrary to the air conditioning apparatus capable of a mixed air-conditioning operation of the heating main operation operation of the plurality of the heating operation and the rest of the cooling operation It is about. Such an air conditioner is a so-called three-pipe type air conditioner in which an outdoor unit and an indoor unit are connected by a high pressure gas pipe, a low pressure gas pipe, and a high pressure liquid pipe, for example, Japanese Patent Application Laid-Open No. 3-63468 (Fig. 2) and Japanese Laid-Open Patent Publication. What is described in 3-63469 publication (FIG. 2) is proposed. That is, in the case of the air conditioner described in Japanese Patent Application Laid-Open No. 3-63468 and Japanese Patent Application Laid-open No. 3-63469, the outdoor unit 1 includes the compressor 2 and the four-way valve as shown in a simplified manner in FIG. (3), the outdoor heat exchanger (4), the expansion valve (5), the receiver tank (6) and the accumulator (7) and the like, the discharge pipe of the compressor (2) branched so that one side of the four-way valve (3) The second port 3B of the four-way valve 3 is connected to the low pressure gas pipe 10 through the capillary tube 9 while being connected to the first port 3A and the other side to the high pressure gas pipe 8. The third port 3C is connected to the outdoor heat exchanger 4 and is connected to the high pressure liquid pipe 11 through the expansion valve 5 and the receiver tank 6. The remaining fourth port 3D of the four-way valve 3 is connected to the low pressure gas pipe 10 similarly to the second port 3B.

On the other hand, a plurality (three in the drawing) of the indoor unit 12 is composed of an indoor heat exchanger 13 and an expansion valve 14 connected thereto, and the high-pressure gas pipe 8, The low pressure gas pipe 10 and the high pressure liquid pipe 11 are connected to the outdoor unit 1. In the indoor unit 12 side, the high pressure gas pipe 8, the low pressure gas pipe 10, and the high pressure liquid pipe 11 are branched by the indoor units 12 through the classifiers 8A, 10A, 11A, respectively, and the high pressure gas pipe 8 is separated. And the low pressure gas pipe 10 is connected to the indoor heat exchanger 13 through open / close valves 8B and 10B in the cold / heat exchanger 15, and the high pressure liquid pipe 11 is connected to the expansion valve 14. have.

When the air conditioner configured as described above performs cooling operation in a plurality (for example, two) of the plurality of indoor units 12 and performs the heating operation in the remaining (for example, one) indoor unit 12, That is, when performing the cooling main body operation, the outdoor unit 1 interconnects the first and third ports 3A and 3C of the four-way valve 3 and the second and fourth ports 3B and 3D are mutually connected. In the indoor unit 12 connected and air-cooled, the on-off valve 8B of the high-pressure gas pipe 8 of the cold / heat exchanger 15 is closed, and the on-off valve 10B of the low-pressure gas pipe 10 is opened. In the indoor unit 12 to be operated, the open / close valve 8B of the high pressure gas pipe 8 is opened and at the same time, the open / close valve 10B of the low pressure gas pipe 10 is closed.

On the contrary, when a plurality of indoor units 12 perform a heating operation and the remaining indoor units 12 perform a heating subject operation that performs a cooling operation, the outdoor unit 1 side of the first and second ports of the four-way valve (3) 3A, 3 kHz are interconnected, and the third and fourth ports 3C, 3D are interconnected, while in the indoor unit 12 which is cooled in the same manner as the cooling main body operation on the indoor unit 12 side, the high pressure gas pipe 8 In the indoor unit 12 which opens and closes the open / close valve 10B of the low pressure gas pipe 10 and heats the operation, the open / close valve 8B of the high pressure gas pipe 8 is opened and the open / close of the low pressure gas pipe 10 is closed. Close the valve 10B.

In the conventional air conditioner, however, the second port 3B of the four-way valve 3 of the outdoor unit 1 is connected to the low pressure gas pipe 10 through the capillary tube 9. This is because the second port 3B is not used at the time of main body operation, but is connected to the first port 3A connected to the discharge side of the compressor 2 to be in a high pressure state.

That is, in the air conditioner, the high-pressure gas pipe 8 is branched between the discharge side of the compressor 2 and the first port 3A of the four-way valve 3 so that the four-way valve 3 is merely an outdoor heat exchanger 4. In the flow path direction of the refrigerant in the air (in the cooling operation, the first and third ports 3A and 3C are connected to each other in the discharge side of the compressor 2 toward the outdoor heat exchanger 4 (in this case, the condenser)). In the case of heating operation, the compressor 2 is connected to the low pressure gas pipe 10 and the accumulator 7 from the outdoor heat exchanger 4 (in this case, the evaporator) by connecting the third and fourth ports 3C and 3D. The four-way valve 3 is substantially used as a three-way valve because it is used only in the direction toward the suction side.

However, although the four-way valve 3 is used as the three-way valve and the second port 3B is not used during the heating operation, when the four-way valve 3 is connected to the first port 3A and becomes a high pressure state, the four-way valve 3 Due to the structure, the high pressure is applied to the internal flow path switching valve, such that the slide valve is inclined, causing an abnormality in its operation, which causes the failure of the four-way valve 3.

In addition, there is a concern that the performance and reliability of the device may be deteriorated by refrigerant condensation and oil pooling at the ports not in use. Accordingly, in the conventional air conditioner, the unused second port 3B is connected to the low pressure gas pipe 10 through the capillary tube 9 for structural reliability of the four-way valve 3. By passing the pressure, the pressure is avoided and refrigerant condensation and oil accumulation are prevented.

However, evacuating the high pressure by bypassing the second port 3B connected to the first port 3A to the low pressure gas pipe 10 is originally supplied from the compressor 2 to the high pressure gas pipe 8 during the heating operation. This means that a part of the refrigerant to be used for heating is returned to the compressor 2 without being used, and as a result, air is reduced by reducing the amount of circulation of the refrigerant that can be supplied to the indoor unit 12 and circulated to the outdoor unit 1. This results in a decrease in performance and efficiency as the roughening device.

In the conventional air conditioner, when the cooling operation is performed in all of the plurality of indoor units 12, the open / close valve 8B on the high-pressure gas pipe 8 side is closed in the cold / heat changer 15, and the low-pressure gas pipe 10 is closed. The deployment closing valve 10B on the side is opened. Therefore, the refrigerant does not flow to the high pressure gas pipe 8 branched between the discharge side of the compressor 2 and the first port 3A of the four-way valve 3, but the on-off valve of the high pressure gas pipe 8 There is a possibility of generating a natural condensation or oil pooling of the remaining refrigerant between 8B), which may also lead to a decrease in the performance of the air conditioner.

However, in order to prevent natural condensation or oil trapping of the refrigerant, it may be considered to install an on-off valve such as a solenoid valve on the branched side of the high pressure gas pipe 8, but at the same time, the high pressure gas pipe 8 may be heated only. In the case of performing, since the refrigerant supplied to all the indoor units 12 flows, it is necessary to use a relatively thick pipe to reduce the pressure loss. Therefore, even if the solenoid valve or the like is installed in the high-pressure gas pipe 8, a large diameter expensive one is required, which inevitably causes a problem of high cost of the device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to discharge from a compressor even when only a heating main operation or a heating operation is performed in a three-tube type air conditioner having a plurality of indoor units as described above. It is an object of the present invention to provide a high-performance and efficient air conditioner that prevents the refrigerant from being bypassed into the low-pressure gas pipe. Also, a large-diameter solenoid valve is not required even when only the cooling operation is performed. It is an object of the present invention to provide an air conditioner that prevents the natural condensation of the refrigerant and prevents the performance and reliability of the oil from degrading.

1 is a diagram showing a state during the cooling main body operation in the first embodiment of the present invention.

Fig. 2 is a diagram showing a state during the heating main operation in the first embodiment of the present invention.

3 is a diagram showing a state during the cooling main body operation in the second example of the present invention.

4 is a view showing a conventional air conditioner.

* Description of the symbols for the main functions of the drawings *

21: outdoor unit 22: compressor

23: Four-way valve 23A to 23D: First to fourth ports of the four-way valve 23

24: outdoor heat exchanger 25, 30: expansion valve

26: receiver tank 27: accumulator

28: indoor 29: indoor heat exchanger

31: cold-heat switch 32: high-pressure gas pipe

33: low pressure gas pipe 34: high pressure liquid pipe

36A: Solenoid valve (flow control valve) 38: High pressure branch pipe

38A: Solenoid valve (opening and closing valve)

The present invention for achieving the above object is an outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger and an expansion valve, a plurality of indoor units having an indoor heat exchanger and an expansion valve, cold and cold switching between the outdoor unit and the indoor unit A high pressure gas pipe, a low pressure gas pipe, and a high pressure liquid pipe connected to each other, wherein the four-way valve connects the compressor to a first port thereof, and connects the high pressure liquid pipe to the second port through the outdoor heat exchanger and the expansion valve. The high pressure gas pipe is connected to a third port, and the low pressure gas pipe is connected to a fourth port, and a high pressure branch pipe is branched between the second port and the high pressure liquid pipe to connect to the high pressure gas pipe to operate the cooling main body of the indoor unit. The first and second ports are connected to each other, and the third and fourth ports are connected to each other. Display is characterized in that a connection to the first and third ports each other, the second, the fourth port each other, respectively.

In the air conditioner of the present invention configured as described above, during the operation of the cooling main body in which a plurality of indoor units are cooled and operated, either the high pressure gas pipe or the low pressure gas pipe is appropriately adapted to the operation form of each indoor unit by the air conditioner on the indoor unit side. The switch is connected to the indoor heat exchanger and the outdoor unit side is connected to the first and second ports of the four-way valve and the third and fourth ports, respectively, as described above. The refrigerant discharged from the compressor is supplied to a plurality of indoor units through an outdoor heat exchanger (in this case, a condenser), an expansion valve, a high pressure liquid pipe, and a cold / heat exchanger from the connected first and second ports and provided for cooling the room. In addition, a part of the refrigerant is supplied to the remaining indoor unit through the high pressure gas pipe and the cold / heat exchanger from the high pressure branch pipe to be provided for heating, and the refrigerant provided for the air conditioning is then returned to the suction side of the compressor through the low pressure gas pipe.

On the contrary, during the operation of the heating main body, a plurality of indoor units are also connected to the high pressure gas pipe by the cold / heat switching unit, and the remaining indoor units are connected to the low pressure gas pipe, while on the outdoor unit side, between the first and third ports of the four-way valves, The fourth ports are connected to each other. The refrigerant discharged from the compressor is supplied from the first and third ports of the four-way valve to the high-pressure gas pipe connected to the third port and the indoor unit performing heating operation through the cold / heat exchanger, and then returned to the outdoor unit from the high-pressure liquid pipe to the expansion valve. In addition, the outdoor heat exchanger (in this case, the evaporator) and the second and fourth ports of the four-way valve are circulated from the low pressure gas pipe to the suction side of the compressor, and a part of the refrigerant flowing into the high pressure liquid pipe is supplied to an indoor unit that performs the cooling operation. And then return to the compressor suction side of the outdoor unit through the low pressure gas pipe from the cold climate changer.

That is, in the air conditioner of the present invention, the pipe connection of the four-way valve of the outdoor unit is independently configured, and the high-pressure gas pipe that has been conventionally branched between the compressor and the first port of the four-way valve is connected to the third port. In this case, the high pressure liquid pipe connected through the outdoor heat exchanger and the expansion valve is connected to the second port and the high pressure branch pipe is connected between the second port and the high pressure liquid pipe toward the high pressure gas pipe. Therefore, it is possible to avoid the generation of unused ports that have become high pressure in the four-way valve, and thus the refrigerant discharged from the compressor can be bypassed to the low-pressure gas pipe, or refrigerant condensation or oil accumulation at the unused ports can be prevented. . In addition, by adopting such a pipe connection configuration, the flow path of the refrigerant flowing through the high pressure gas pipe and the low pressure gas pipe is constant during the cooling / heating main body operation, the cooling / heating alone operation, or even when the cooling / heating load is balanced. Therefore, even in switching the flow path directions for cooling / heating, a complicated valve mechanism is not required, so that the cost of the device can be suppressed.

In addition, in the air conditioner of the present invention, since the high pressure branch pipe merely allows some of the refrigerant discharged from the compressor during the operation of the cooling main body to be branched between the high pressure liquid pipe from the second port of the four-way valve and supplied to the high pressure gas pipe. In order to prevent the inflow of the refrigerant into the high pressure gas pipe in the case of performing only the cooling operation, it is sufficient to provide a low-diameter solenoid valve or the like even if an open / close valve is provided in the high pressure branch pipe. Accordingly, it is possible to reliably prevent a situation such as natural condensation or oil accumulation in the high-pressure gas pipe due to the inflow of the refrigerant while preventing the cost of the device from being expensive.

The high pressure branch pipe may be connected to the high pressure gas pipe by branching between the four-way valve and the outdoor heat exchanger. For example, in the case of using an azeotropic mixed refrigerant as the refrigerant, the expansion valve and the high pressure liquid pipe of the outdoor unit may be used. It may be connected to the high-pressure gas pipe from a receiver tank provided between the above, and this configuration makes it possible to selectively use a refrigerant having a large latent heat (or a high refrigerating capacity) even with a relatively small amount of refrigerant during the operation of the cooling main body. Since the heating capability can be ensured and the saturated gas in the two-phase refrigerant is used, heat exchange can be performed efficiently. Also, by providing a flow regulating valve in parallel with the expansion valve between the outdoor heat exchanger and the high pressure liquid pipe, the flow rate adjustment of the refrigerant flowing from the high pressure branch pipe to the high pressure gas pipe and the refrigerant flowing into the high pressure liquid pipe during the operation of the cooling main body is also performed. It becomes possible to carry out with a valve.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 show a first embodiment of the present invention. In the present embodiment, the outdoor unit 21 includes a compressor 22, a four-way valve 23, an outdoor heat exchanger 24, an expansion valve 25, a receiver tank 26, and an accumulator 27. A plurality of indoor units 28 (four in the present embodiment) are provided, and each includes an indoor heat exchanger 29 and an expansion valve 30 connected in series thereto, and the indoor units 28 are the outdoor units 21. The high pressure gas pipe 32, the low pressure gas pipe 33, and the high pressure liquid pipe 34 are connected to each other through the cold / heat switch 31.

Here, the high pressure gas pipe 32, the low pressure gas pipe 33, and the high pressure liquid pipe 34 may branch from the cold / heat exchanger 31, and the branched high pressure liquid pipe 34 may be the expansion valve 30 of the indoor unit 28. Are respectively connected to the In addition, the high pressure gas pipe 32 and the low pressure gas pipe 33 are respectively connected to the indoor heat exchanger 29 of the indoor unit 28 via solenoid valves 32A and 33A serving as switching valves in the cold / heat exchanger 31. At the same time, it is possible to connect with each other via the solenoid valve 35A and the capillary tube 35B on the side closer to the outdoor unit 21 than these solenoid valves 32A and 33A. On the other hand, the solenoid valve 35A is preferably a pressure mechanism capable of being fully closed, and for example, an electromagnetic expansion valve (electric expansion valve) or the like that can be fully closed is preferable.

On the other hand, in the outdoor unit 21, the low pressure gas pipe 33 is connected to the suction side of the compressor 22 via the accumulator 27, and the outdoor heat exchanger 24 and the expansion valve 25 are connected in series. The high pressure liquid pipe 34 is connected to the expansion valve 25 via a receiver tank 26. On the other hand, the outdoor heat exchanger 24 according to the present embodiment has a configuration in which a plurality of heat exchangers (two in the drawing) are connected in parallel. Moreover, between these outdoor heat exchangers 24 and the high pressure liquid pipe 34, the solenoid valve 36A which functions as a flow control valve in this embodiment on the side closer to the outdoor heat exchanger 24 than the said receiver tank 26. Is connected in parallel with the expansion valve 25 together with the check valve 36B. During the cooling operation, the liquid refrigerant from the outdoor heat exchanger 24 supplies the solenoid valve 36A and the check valve 36B. It can be passed and bypass the expansion valve 25, the bypass is closed during the heating operation, such that the refrigerant can pass through the expansion valve (25).

The four-way valve 23 of the outdoor unit 21 is connected to the first port 23A via the oil separator 37 at the discharge side of the compressor 22, and the second port 23B is connected to the outdoor heat exchanger. Is connected to the high pressure liquid pipe 34 via the air conditioner 24, the expansion valve 25, and the receiver tank 26, and the third port 23C is connected to the high pressure gas pipe 32, and the fourth port (23D). Are respectively connected to the low pressure gas pipe 33. Among these, the high pressure branch pipe 38 branches between the second port 23B and the high pressure liquid pipe 34 and is connected to the high pressure gas pipe 32. In particular, in the present embodiment, the high pressure branch pipe 38 Branching is performed between the second port 23B of the four-way valve 23 and the outdoor heat exchanger 24.

The high-pressure branch pipe 38 is provided with a solenoid valve 38A functioning as an on / off valve in this embodiment together with a check valve 38B for preventing the backflow of refrigerant from the high-pressure gas pipe 32 side. In addition, between the third port 23C of the four-way valve 23 and the high-pressure gas pipe 32, the side closer to the four-way valve 23 than the connection portion between the high-pressure gas pipe 32 and the high-pressure branch pipe 38 is also present. The check valve 39 which prevents the backflow of the refrigerant from the high-pressure gas pipe 32 side is provided. However, the valve provided between the third port 23C and the high pressure gas pipe can also use an solenoid valve instead of the check valve 39. The fourth port 23D of the four-way valve 23 is connected to the low pressure gas pipe 33 on the downstream side (indoor 28 side) than the accumulator 27.

In the case of performing the cold / heat mixed operation by the air conditioner of the present embodiment configured as described above, as shown in FIG. 1, a plurality of the indoor units 28 (three in the upper side in FIG. 1) are cooled in operation. And the first port 23A and the second port 23B of the four-way valve 23 are connected to each other during the cooling main body operation in which the remaining indoor unit 28 (the lowest one in FIG. 1) is heated. 23C and the fourth port 23D are connected. On the contrary, as shown in FIG. 2, a plurality of indoor units 28 (three in the lower side in FIG. 2) are heated and the remaining indoor units 28 (one in the uppermost one in FIG. 2) are cooled in operation. In the main body operation, the four-way valve 23 is connected to the first port 23A and the third port 23C, and is connected to the second port 23B and the fourth port 23D.

That is, in operation of the cooling main body, the outdoor unit 21 side, as described above, between the first, second ports 23A, 23B, and the third, fourth ports 23C, ( 23D) The high-pressure gas pipe 32 of the indoor unit 28 that is connected to each other and at the same time the solenoid valve 38A of the high-pressure branch pipe 38 is opened and is cooled in the air conditioner 31 on the indoor unit 28 side. The solenoid valve 32A of the low-pressure gas pipe 33 is opened and the solenoid valve 33A of the low-pressure gas pipe 33 is opened, and the solenoid valve 32A of the high-pressure gas pipe 32 of the indoor unit 28 which is heated and operated on the contrary is opened and the low pressure gas pipe 33 is opened. Solenoid valve 33A is closed.

Therefore, as indicated by the arrow in FIG. 1, the refrigerant discharged from the compressor 22 is condensed by the outdoor heat exchanger 24 via the first and second ports 23A and 23B of the four-way valve 23, and thus, the high pressure. As the liquid refrigerant, it is supplied to the indoor unit 28 for cooling operation through the expansion valve 25 and the receiver tank 26 through the high pressure liquid pipe 34, and decompressed in the expansion valve 30 to evaporate in the indoor heat exchanger 29. As a result, the room can be cooled and circulated to the suction side of the compressor 22 through the accumulator 27 via the low pressure gas pipe 33 through the solenoid valve 33A of the cold / heat switching unit 31 as the low pressure gas. In addition, a part of the refrigerant discharged from the compressor 22 and passed through the four-way valve 23 branches to the high-pressure branch pipe 38 in which the solenoid valve 38A is opened, and passes through the high-pressure gas pipe 32 to the air conditioner 31. It is supplied to the indoor unit 28 for heating operation through the solenoid valve 32A and condensed in the indoor heat exchanger 29 to heat the room, and then to the high pressure liquid pipe 34 through the expansion valve 30 to supply the cooling operation. The refrigerant may be combined with the refrigerant supplied to the indoor unit 28 and provided for cooling and then circulated to the compressor 22 through the low pressure gas pipe 33.

On the other hand, during the operation of the heating main body, the outdoor unit 21 side, as described above, between the first, third ports 23A, 23C, and the second, fourth ports 23B, 23D of the four-way valve 23. The solenoid valves 38A of the high pressure branch pipe 38 are closed at the same time that they are connected to each other. In the case of the indoor unit 28 which is heated and operated in the same manner as in the cooling main body operation on the indoor unit 28 side, the solenoid valve 32A of the high pressure gas pipe 32 is opened in the air conditioner 31 and the low pressure gas pipe 33 is opened. The solenoid valve 33A of the ()) is closed, and the solenoid valve 32A of the high pressure gas pipe 32 of the indoor unit 28 which is operated by cooling is closed, and the solenoid valve 33A of the low pressure gas pipe 33 is opened.

In the case of such a heating main body operation, the refrigerant discharged from the compressor 22 passes through the check valve 39 through the first, third ports 23A, 23C of the four-way valve 23 as indicated by the arrow in FIG. Is supplied to the high-pressure gas pipe (32) and supplied to the indoor heat exchanger (29) of the indoor unit (28) for heating operation from the solenoid valve (32A) of the cold / heat exchanger (31) to heat the room and condense the expansion valve. It is sent to the high pressure liquid tube 34 through the (30). Here, a part of the refrigerant sent to the high pressure liquid tube 34 is supplied to the indoor unit 28 for cooling operation and evaporated in the indoor heat exchanger 29 to be used for cooling the room, and to the indoor heat exchanger 29 as well. It can be circulated to the suction side of the compressor 22 via the connected low pressure gas pipe 33 and via the accumulator 27. In addition, the remaining refrigerant sent to the high-pressure liquid pipe 34 is also returned to the outdoor unit 21 side and evaporated by the outdoor heat exchanger 24 through the receiver tank 26 and the expansion valve 25, and then the four-way valve 23 It may be circulated from the low pressure gas pipe 33 through the accumulator 27 to the compressor 22 via the third and fourth ports 23C and 23D.

In addition, when performing an operation in which loads of cooling / heating are balanced, such as when the number of cooling operations and the number of heating operations among the plurality of indoor units 28 are the same, for example, when the outdoor temperature is low, the outdoor unit 21 is everywhere. The connection of the 1st-4th ports 23A-23D of the valve 23 is made to be the same as that of the heating main body operation, and the solenoid valve 38A of the high pressure branch pipe 38 is also closed, and the indoor unit 28 side is the same. The solenoid valves 32A and 33A are opened and closed in the same manner as in the cooling / heating main operation for the cooling / heating operation. In this case, the refrigerant discharged from the compressor 22 is first heated by the high pressure gas pipe 32 and the cold / heat switch 31 through the first, third ports 23A, 23C of the four-way valve 23. It is supplied to the indoor unit 28 to perform condensation and used for indoor heating. Then, it is supplied to the indoor unit 28 performing cooling operation through the high-pressure liquid tube 34 from the cold / heat exchanger 31 and evaporated to be used for cooling the room. After it is made, it is circulated to the suction side of the compressor 22 through the low pressure gas pipe 33 and the accumulator 27. Therefore, in this case, the cold / heat exchanger (2) is provided from the second port 23B of the four-way valve 23 through the high pressure branch pipe 38 and the outdoor heat exchanger 24, the expansion valve 25, and the receiver tank 26. The refrigerant does not flow between the portion of the high pressure liquid pipe 34 up to 31) and the low pressure gas pipe 33 through the fourth port 23D. On the contrary, when the outdoor temperature is high, it is possible to perform the balanced operation by connecting the same as in the cooling main body operation. In this way, if connected in the same way as any one of the main operation of cooling / heating according to the outdoor temperature, the cooling load increases when the outdoor temperature is high, or conversely, even when the heating load increases when the outdoor temperature is low (23) It is possible to quickly shift to cooling subject operation or heating subject operation without switching).

In the case of cooling all the indoor units 28, the connection of the ports 23A to 23D of the four-way valve 23 on the outdoor unit 21 side is the same as that of the cooling main body operation, and the solenoid valve of the high-pressure branch pipe 38 38A) is closed, the solenoid valve 36A is opened, and the solenoid valve 32A of the air-conditioner 31 is opened, and the solenoid valve 33A is closed on the indoor unit 28 side. In this case, the refrigerant does not flow in the high-pressure gas pipe 32. On the other hand, when all the indoor units 28 are heated and operated, the four-way valve 23 is the same as in the heating main operation, and the solenoid valve 38A of the high-pressure branch pipe 38 is also closed and the cold / heat exchanger 31 is closed. The solenoid valve 32A is opened, and the solenoid valve 33A is closed. In this case, the refrigerant does not flow in the low pressure gas pipe 33.

Therefore, in the air conditioner having such a configuration, since there is only one four-way valve 23, the cycle configuration is simple, and either the cooling operation or the heating operation can be mainly used, or it is possible to enable the mixed operation of the heating and cooling in which both loads are balanced. It is possible to perform air conditioning according to the needs of each room. In addition, in the case of the mixed air-conditioning operation, the heat discharged to the outside during cooling can be used for heating, or the heat introduced from the outside during heating can be introduced from the room requiring cooling, thereby reducing the load on the outdoor unit 21 side. Efficient and economical operation of cold and hot mixed operation can be performed.

When the refrigerant flows in the high-pressure gas pipe 32 and the low-pressure gas pipe 33 among the three pipes connecting the outdoor unit 21 and the indoor unit 28 even in the air-cooled mixed operation or the cooling or heating alone operation, the flow direction, that is, the flow path direction. Since the constant is always constant, there is no need to use a complicated valve mechanism to switch the flow path direction, and the cycle configuration can be simplified, thereby making it possible to construct a low cost apparatus.

Further, in the air conditioner of the present embodiment, the four-way valve 23 of the outdoor unit 21 has a first port 23A connected to the discharge side of the compressor 22, and the second port 23B is an outdoor heat exchanger ( 24 and the third port 23C are connected to the high pressure gas pipe 32 and the fourth port 23D is connected to the low pressure gas pipe 33 through the expansion valve 25. The high pressure branch pipe 38 branches between the two ports 23B and the high pressure liquid pipe 34 and is connected to the high pressure gas pipe 32. During the heating main operation, the first, third ports 23A, 23C Are connected to the second and fourth ports 23B, 23D. Therefore, during the operation of the heating main body, the discharge side of the compressor 22 is directly connected to the high-pressure gas pipe 32 through the first, third ports 23A, 23C of the four-way valve 23 as it is. The case where the port connected to the discharge side of the compressor 22 and the high pressure state is not used does not occur, and it is not necessary to forcibly bypass this port to the low pressure gas pipe 33. The same applies to the case of performing only heating operation or performing a balanced operation of cooling / heating load.

Therefore, according to the present embodiment, while the structural reliability of the four-way valve 23 is sufficiently secured, the amount of circulation of the refrigerant is reduced by bypassing the high pressure refrigerant discharged from the compressor 22 to the low pressure gas pipe 33 through the indoor unit ( It does not cause performance degradation as an air conditioner such that the heating capacity on the 28) side is impaired. In addition, the performance and reliability of the air conditioner are not deteriorated by the refrigerant condensation or oil pooling at the unused port as described above, so that a high performance and efficient air conditioner can be provided and the comfort can be improved.

On the other hand, during the operation of the cooling main body, the first, second ports 23A, 23B of the four-way valve 23 are connected and the third, fourth ports 23C, 23D are connected, and thus the compressor 22 ), The refrigerant discharged from the high pressure liquid is supplied from the high pressure liquid pipe 34 to the indoor unit 28 for cooling operation through the first and second ports 23A and 23B. Do not. The same applies to the case where only the cooling operation is performed. In addition, a part of the refrigerant that has passed through the four-way valve 23 during the operation of the cooling main body is branched to the high pressure branch pipe 38 and supplied to the indoor unit 28 for heating operation from the high pressure gas pipe 32 to perform the cooling and hot air mixing operation reliably. It becomes possible.

The high-pressure branch pipe 38 is provided with a solenoid valve 38A as an on-off valve in the present embodiment, and is cooled in operation when no refrigerant is passed through the high-pressure branch pipe 38 except for the cooling main body operation. Inflow of the coolant into the high pressure gas pipe 32 at the time and the reverse flow of the coolant from the high pressure gas pipe 32 at the time of other operation can be prevented.

In addition, the high pressure branch pipe 38 performs only a function of supplying only a part of the refrigerant during the operation of the cooling main body to supply a small number of indoor units 28 for heating operation from the high pressure gas pipe 32 so that the relatively thin pipe may be configured. Therefore, the solenoid valve 38A provided in this high pressure branch pipe 38 can also use a small diameter inexpensive one. As a result, according to the present embodiment, a general-purpose solenoid valve 38A can be used as the on-off valve, thereby preventing the cost of the apparatus and condensing the refrigerant in the high-pressure gas pipe 32 especially when only cooling operation is performed. It is also possible to reliably prevent oil trapping and improve the performance of the device.

In the present embodiment, the flow control valve is arranged in parallel with the expansion valve 25 between the outdoor heat exchanger 24 and the high pressure liquid tube 34 of the outdoor unit 21, and more specifically, between the receiver tank 26. The solenoid valve 36A is provided, and is supplied from the solenoid valve 36A by the solenoid valve 36A to the indoor unit 28 for heating operation, which is branched from the high pressure branch pipe 38 and flows to the high pressure gas pipe 32 during the operation of the cooling main body. It is possible to perform flow rate adjustment of the refrigerant and the refrigerant flowing into the high pressure liquid tube 34 through the outdoor heat exchanger 24, that is, the refrigerant supplied to the indoor unit 28 for cooling operation. Therefore, according to the cooling / heating requirements of the indoor unit 28 during the operation of the cooling main body, it is possible to supply the refrigerant having a predetermined flow rate to each of the indoor units 28 that are cooled / heated on the outdoor unit 21 side more reliably. It can promote cold and hot mixed operation.

In the first embodiment, however, the high pressure branch pipe 38 branches between the second port 23B of the four-way valve 23 and the outdoor heat exchanger 24 and is connected to the high pressure gas pipe 32. During the operation of the cooling main body, it is possible to supply high-pressure refrigerant before passing through the outdoor heat exchanger 24 to the indoor unit 28 for heating operation through the high-pressure gas pipe 32 to perform efficient heating. In the case of using a coolant or the like, the high pressure branch pipe 38 is installed between the expansion valve 25 and the high pressure liquid pipe 34 of the outdoor unit 21 as in the second embodiment of the present invention shown in FIG. Branching from the receiver tank 26 may be connected to the high pressure gas pipe 32. Here, the high pressure branch pipe 38 in the second embodiment branches at the upper portion of the receiver tank 26. FIG. 3 is a diagram illustrating the operation of the cooling main body in the second embodiment, in which elements common to those of the first embodiment shown in FIGS. 1 and 2 are commonly denoted by the same reference numerals, and detailed description thereof will be omitted. Shall be. That is, for example, in a non-azeotropic mixed refrigerant such as R407C (R32 / 125 / 134a: 23/25 / 52wt%), the low boiling point component (low boiling point refrigerant, R32 / 125 in R407C) has a unit mass compared to the high boiling point component. The latent heat of sugar, that is, the freezing capacity is high, and the gas component is liable to be gasified due to low boiling point.

Therefore, in the case of using such azeotropic mixed refrigerant, according to the second embodiment, the ability of the outdoor heat exchanger 24 to become a condenser during the operation of the cooling main body is suppressed, so that the refrigerant at the condenser outlet is made into the liquid gas two phase and the receiver is used. By separating from the tank 26 and branching into the high-pressure gas pipe 32 through the high-pressure branch pipe 38, the gas component of the low boiling point component can be efficiently used, so that the latent heat is large (or the freezing capacity is large) even in a relatively small amount of refrigerant. The refrigerant can be selectively used, and the heating capability can be reliably ensured in the indoor unit 28 for heating operation. In addition, since the gas refrigerant extracted from the two-phase refrigerant is saturated gas, unlike the superheated gas discharged from the compressor 22, the gas refrigerant starts to condense directly in the indoor heat exchanger 29, so that the heat of condensation may be efficiently used. However, the second embodiment is not necessarily limited to the case of using the above azeotropic mixed refrigerant as the refrigerant, but is also applicable to the use of other refrigerants, for example, even when a single refrigerant such as R22 is used. By using, the same efficiency can be increased.

As described in detail above, the present invention is a three-pipe type air conditioner in which an outdoor unit and an indoor unit are connected by a high pressure gas pipe, a low pressure gas pipe, and a high pressure liquid pipe, and in any case of a cooling / heating main body operation to a four-way valve of the outdoor unit. It is possible to prevent the occurrence of an unused port which becomes a high pressure state. Therefore, by preventing the unused port from becoming a high pressure state, the refrigerant discharged from the compressor is bypassed to the low pressure gas pipe, thereby causing a decrease in the amount of circulating refrigerant or generating a refrigerant condensation or oil accumulation at the unused port. Problems such as deterioration in performance and reliability can be prevented, and an efficient and high performance air conditioner can be provided.

In addition, the high-pressure branch pipe branched to the high-pressure gas pipe between the second port of the four-way valve and the high-pressure liquid pipe through the outdoor heat exchanger can be a relatively thin pipe, so that an inexpensive shut-off valve having a relatively small diameter is used as the high-pressure branch pipe. It can prevent the cost increase and reliably prevent the deterioration of the device's performance and reliability caused by the natural condensation of refrigerant in the high-pressure gas pipe during cooling operation and oil accumulation. It also improves the performance while suppressing the high cost of the device. It can be planned even more. In addition, by branching the high pressure branch pipe between the four-way valve and the outdoor heat exchanger, efficiency can be further improved, for example, when an azeotropic mixed refrigerant is used as the refrigerant, between the expansion valve of the outdoor unit and the high pressure liquid pipe. By branching from the receiver tank, the heating capacity can be reliably ensured even with a relatively small amount of refrigerant during the operation of the cooling main body, and efficient heat exchange can be performed by using a saturated gas component. In addition, by installing a flow regulating valve in parallel with the expansion valve between the outdoor heat exchanger and the high pressure liquid pipe, the flow rate adjusting valve can adjust the flow rate of the refrigerant flowing into the high pressure gas pipe and the refrigerant flowing into the high pressure liquid pipe during the operation of the cooling main body. As a result, efficient cold and hot mixed operation can be performed.

Claims (5)

An outdoor unit having a compressor, a four-way valve, an outdoor heat exchanger, and an expansion valve, A plurality of indoor units having an indoor heat exchanger and an expansion valve, It has a high pressure gas pipe, a low pressure gas pipe and a high pressure liquid pipe that is connected between the outdoor unit and the indoor unit through a cold and heat exchanger, In the four-way valve, the compressor is connected to the first port, the high pressure liquid pipe is connected to the second port through the outdoor heat exchanger and the expansion valve, the high pressure gas pipe is connected to the third port, and the low pressure is connected to the fourth port. A gas pipe is connected, and a high pressure branch pipe is branched between the second port and the high pressure liquid pipe to be connected to the high pressure gas pipe. During the cooling main body operation of the indoor unit, the first and second ports are connected to each other. And fourth ports are connected to each other, and the first and third ports and the second and fourth ports are connected to each other during the operation of the heating main body. The method of claim 1, The air conditioner, characterized in that the high-pressure branch pipe is provided with an on-off valve. The method according to claim 1 or 2, And the high pressure branch pipe is branched between the four-way valve and the outdoor heat exchanger and connected to the high pressure gas pipe. The method according to claim 1 or 2, A receiver tank is provided between the expansion valve and the high pressure liquid pipe of the outdoor unit, and the high pressure branch pipe is connected to the high pressure gas pipe from the receiver tank. The method according to any one of claims 1 to 4, And a flow rate control valve is provided in parallel with the expansion valve between the outdoor heat exchanger and the high pressure liquid pipe.