JPH09229508A - Multi air conditioner - Google Patents

Abstract

(57) Abstract: In a multi-air conditioner having a plurality of indoor units and a plurality of outdoor units, the number of pipes for transporting a refrigerant between them is reduced as compared with a conventional one, and operation is performed. . SOLUTION: A plurality of indoor units 2a to 2d, a plurality of outdoor units 1a and 1b, liquid pipes 3 ₁ and 3 ₂ and gas pipes 4 ₁ and 4 ₂ provided in each indoor unit and each outdoor unit. In the multi-air conditioner having the indoor expansion valve 14 provided in each indoor unit, the gas pipes of each outdoor unit are integrated and connected to one end, and the other end is connected to each indoor unit side in common. Gas pipe 4
And a single common liquid pipe 3 in which liquid pipes of a plurality of indoor units are aggregated and connected to one end, and the other end is connected to each outdoor unit side. One common gas pipe and one common liquid pipe The common liquid pipe of is shared as a pipe for transporting the refrigerant, and only the indoor expansion valve of the indoor unit to be operated is opened to control the opening degree according to each indoor load.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multi-air conditioner including a plurality of outdoor units and a plurality of indoor units,
In particular, it relates to the integration of refrigerant transport pipes.

[0002]

2. Description of the Related Art Conventionally, in a multi-air conditioner composed of a plurality of outdoor units and a plurality of indoor units, the pipes arranged for the purpose of transporting the refrigerant between the outdoor units and the indoor units are It was necessary for each indoor unit group connected to the machine. Related to this type of device, for example, Japanese Examined Patent Publication No. 56-49856 (Prior Art 1) and Japanese Patent Laid-Open Publication No.
-82035 gazette (prior art 2) is mentioned.

[0003]

In the above-mentioned prior art 1,
The number of pipes for refrigerant transport between the outdoor unit and the indoor unit group in the entire multi-air conditioner is the sum of the number of pipes in each group, and as the number of outdoor units increases, the number of pipes also increases, resulting in complicated piping work. And increased construction costs due to increased pipe usage, and a decrease in available space in the building due to an increase in piping shafts.

Further, in the above-mentioned prior art 2, as shown in FIG. 1, pipes (branch pipes 32 and 42) for transporting the refrigerant between the outdoor unit and the indoor unit are provided for each outdoor unit, Even when using a plurality of outdoor units, the pipes for transporting the refrigerant between the outdoor unit and the indoor unit are not made into one system such as one common liquid pipe and one common gas pipe, Further, in the conventional technique, the gas pipe of the outdoor unit and the liquid pipe of the indoor unit are not integrated into one end of the closed loop gas pipe and the closed loop liquid pipe, respectively. Therefore, in the same prior art, a difference in flow velocity occurs due to a difference in pressure loss in the middle of each closed-loop pipe or in each refrigerant transport pipe for each outdoor unit, and the refrigerant is distributed to each indoor unit in a pipe with a slow flow velocity. Control becomes difficult.

The present invention solves the problems of the prior art as described above, and the refrigerant transportation between the outdoor unit and the indoor unit of the multi-air conditioner is performed by one common unit regardless of the number of the outdoor unit and the indoor unit. Liquid pipes and one common gas pipe are combined into two pipes to simplify piping work, reduce the amount of pipes used, and effectively use the space inside the building, and add or reduce outdoor units and indoor units. The purpose is to facilitate.

Further, according to the present invention, in a multi-air conditioner, when a plurality of compressors provided in each outdoor unit are operated, due to the operating conditions thereof, the amount of oil returned is uneven and a shortage of oil supply occurs in a certain compressor. In some cases, it is intended to prevent the seizure of the compressor from occurring.

[0007]

In order to achieve the above object, a multi air conditioner according to the invention of the present application is provided with a plurality of indoor units, a plurality of outdoor units, the indoor units and the outdoor units. In a multi-air conditioner having a liquid pipe and a gas pipe provided in, and an indoor expansion valve provided in each indoor unit, the gas pipes of each of the plurality of outdoor units are aggregated and connected to one end side thereof, The other end side is connected to one common gas pipe connected to each indoor unit side and the liquid pipes of the plurality of outdoor units to be connected to one end side thereof, and the other end side is connected to each indoor unit side. A common liquid pipe connected to the common gas pipe, and the common gas pipe and the common liquid pipe are shared as a pipe for transporting the refrigerant between the outdoor unit and the indoor unit during operation. , The indoor expansion valve of the indoor unit to be stopped is closed and is the one common liquid pipe? Prevents the flow of refrigerant to the indoor unit for stopping the operation, the said indoor expansion valve of another indoor unit and controls in accordance with the indoor load.

In the above-mentioned multi-air conditioner, each of the indoor units to be operated may be integrally operated as cooling or heating.

In the above multi-air conditioner, when an outdoor unit is added, the gas pipe of the outdoor unit to be added is connected to the one end of the one common gas pipe, and the one common gas pipe including the added outdoor unit is connected. The gas pipe may be shared as a pipe for transporting a refrigerant between the outdoor units and the indoor units during operation, and the outdoor units may be controlled as a set.

The multi-air conditioner according to the invention of the present application is a multi-air conditioner having a plurality of outdoor units, a plurality of indoor units, and a refrigerant pipe provided in each of the outdoor units and each of the indoor units, A header that aggregates the refrigerant pipes of each of the outdoor units, and a single-system refrigerant pipe that has the header connected to one end and the other end connected to each indoor unit side. An outdoor unit to be added to is connected to, and the refrigerant pipe of the one system including the added outdoor unit is shared as a pipe for refrigerant transport between each of the outdoor units and each of the indoor units at the time of operation, and is added. The above-mentioned outdoor units including the outdoor unit are controlled as a set.

The multi-air conditioner according to the invention of the present application is a multi-air conditioner having a plurality of indoor units, a plurality of outdoor units, and refrigerant pipes provided in each of the indoor units and each of the outdoor units, The refrigerant pipes of each of the plurality of outdoor units are aggregated and connected to one end side thereof, and the other end side is provided with one common refrigerant pipe connected to each indoor unit side, and inside the common refrigerant pipe during operation. It is characterized in that it is in a gas / liquid two-phase state.

[0012]

According to the present invention, the refrigerant is transported between the outdoor unit and the indoor unit regardless of the number of the outdoor units and the indoor units, when each of the outdoor units is in operation with one common liquid pipe and one common gas pipe. Since it is shared as a pipe for refrigerant transportation between each indoor unit, the amount of piping used can be reduced and the piping work can be simplified, the space inside the building can be effectively used, and an outdoor unit and an indoor unit can be added. Or, it can be easily reduced.

When the compressor provided in each outdoor unit is operated, the oil in the oil separator that separates the oil from the refrigerant gas discharged from the compressor is returned to and supplied to the plurality of compressors. However, it is possible to avoid non-uniformity of the oil return amount under any operating condition, so it is possible to prevent oil supply shortage in one of the compressors and, in some cases, seizure in that compressor. It can be prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a pipe arrangement diagram of an embodiment in which the refrigerant transport pipes between a plurality of outdoor units and a plurality of indoor units are integrated into two. The liquid pipe 3 ₁ and the gas pipe 4 _{1 of} each of the outdoor units 1a and 1b, and the liquid pipe 3 ₂ and the gas pipe 4 ₂ of each of the indoor units 2a, 2b, 2c and 2d are used as a common liquid between the outdoor unit and the indoor unit. The pipe 3 and the gas pipe 4 are respectively connected to carry the refrigerant. Also,
The outdoor units 1a and 1b are connected to each other by a pressure equalizing pipe 9 and an oil equalizing pipe 10 to prevent an unbalanced amount of oil supply to the compressor of each outdoor unit.

FIG. 2 is a block diagram of the refrigeration cycle of FIG.
As shown, each of the outdoor units 1a and 1b includes a compressor 11,
A four-way valve 12 for switching between heating and cooling, outdoor heat exchangers 13 ₁ and 13 ₂ divided into _two , and an electronic expansion valve 3 having a variable opening degree for the outdoor heat exchangers 13 ₁ and 13 ₂ .
3 ₁ , 33 ₂ , a receiver 34, an accumulator 32, and a liquid return passage with a flow rate adjusting valve 35 connecting the receiver 34 and the gas suction side of the compressor 11. Indoor unit 2
Each of a, 2b, 2c and 2d has an indoor heat exchanger 15 and an electronic expansion valve 14 with a variable opening. In FIG. 2, the pressure equalizing pipe 9,
Although illustration of the oil equalizing pipe 10 is omitted, this will be described later with reference to FIG.

In this embodiment, all the indoor units are unified to either the heating operation or the cooling operation (however, including the case where any given indoor unit is stopped). Below is the outdoor unit 1
The operation will be described by taking a as an example, but the operation is the same for other outdoor units.

During the cooling operation, the compressor 11 of the outdoor unit 1a
The high-temperature and high-pressure gas discharged from the gas passes through the four-way valve 12 and is heat-exchanged by the outdoor heat exchangers 13 ₁ and 13 ₂ to become a liquid refrigerant (in this case, the outdoor electronic expansion valves 33 ₁ and 33 ₂ are fully opened). . The liquid refrigerant flows through the receiver 34, the liquid pipe 3 ₁ , and the common liquid pipe 3 into the liquid pipe 3 ₂ of each operating indoor unit, is decompressed by the electronic expansion valve 14, and is heated by the indoor heat exchanger 15 to the indoor air and heat. It is replaced and becomes low-pressure gas. Low-pressure gas is the gas pipe 4 ₂ of each indoor unit.
Through the common gas pipe 4 and the gas pipe 4 of the outdoor unit 1a
_It passes through ₁ and returns to the compressor 11 via the four-way valve 12 and the accumulator 32, becomes compressed high temperature and high pressure refrigerant gas, and is discharged again.

The following is performed during the heating operation. Outdoor unit 1
The high-temperature and high-pressure gas discharged from the compressor 11 of a passes through the four-way valve 12, the gas pipe 4 ₁ , and the common gas pipe 4 and is branched into the gas pipe 4 ₂ of each indoor unit in operation, and the indoor heat exchanger. At 15 the heat is exchanged with the indoor air to become a liquid refrigerant (in this case, the indoor electronic expansion valve 14 is fully opened). The liquid refrigerant merges with the common liquid pipe 3 through the liquid pipe 3 ₂ , passes through the liquid pipe 3 ₁ of the outdoor unit 1a and the receiver 34, and is decompressed by the outdoor electronic expansion valves 33 ₁ and 33 ₂ to obtain the outdoor heat exchanger. At 13 ₁ and 13 ₂ , heat is exchanged with the outdoor air to form low-pressure gas, which returns to the compressor via the four-way valve 12 and the receiver 32 and is discharged again.

In any of the above heating operation or cooling operation, the electronic expansion valve 14 of the stopped indoor unit is closed.
A plurality of outdoor units operate all or one of them, and further, both the heat exchangers 13 ₁ and 13 ₂ of the operating outdoor unit are operated or only one of them is operated (the electronic expansion valve 33 ₁ , 33 ₂ is closed). The selection and combination are controlled according to the required cooling or heating load. Further, each indoor expansion valve 14 is controlled so that the refrigerant is appropriately distributed to each indoor unit according to each indoor load. The amount of liquid returned to the compressor 11 is adjusted by the flow rate adjusting valve 35 in the outdoor unit to control the temperature of the gas discharged from the compressor.

FIG. 3 is a pipe arrangement diagram of an embodiment in which the refrigerant transportation pipes between a plurality of outdoor units and a plurality of indoor units are integrated into three. Outdoor unit 5a, 5b each of the liquid pipe _35, the high-pressure gas pipe 6 _5, the low-pressure gas pipe 7 _5, and the indoor unit 2a, 2
b, 2c, 2d each liquid pipe 3 _2, high-pressure gas pipe 6 _2, a low-pressure gas pipe 7 _2, the outdoor unit - a common liquid pipe 3 between the indoor unit, the high-pressure gas pipe 6, respectively connected to the low-pressure gas pipe 7 Then, the refrigerant is transported. Further, the outdoor units 5a and 5b are connected to each other by a pressure equalizing pipe 9 and an oil equalizing pipe 10.
Contact us to maintain a balance of the amount of oil supplied to the compressors of each outdoor unit.

FIG. 4 is a configuration diagram of the refrigeration cycle of FIG.
As shown, each of the outdoor units 5a and 5b includes a compressor 16,
Two four-way valves 17 ₁ and 17 ₂ , two outdoor heat exchangers 18 ₁ and 18 ₂ , and electronic expansion valves 19 ₁ and 1 corresponding thereto
9 ₂ , a receiver 34, an accumulator 32, and a liquid return passage with a flow rate adjusting valve 35 connecting the receiver 34 and the suction side of the compressor 16. Although the pressure equalizing pipe 9 and the oil equalizing pipe 10 are not shown in FIG. 4, they will be described later in FIG. Each of the indoor units 2a, 2b, 2c, 2d has a variable opening electronic expansion valve 14 and an indoor heat exchanger 15, and an indoor cooling / heating switching unit 8 is attached to each indoor unit.

In the present embodiment, while one arbitrary indoor unit or a plurality of indoor units are operated for heating, at the same time, another one or a plurality of indoor units are subjected to cooling operation (so-called simultaneous cooling / heating operation). Either the air conditioner operation of the machine or the heating operation of all the indoor units is possible (including the case where any indoor unit is stopped). In the indoor unit of the cooling operation, the indoor cooling and heating switching unit 8 is switched so as to communicate with the indoor heat exchanger 15 and the low-pressure gas pipe 7 _2. In the indoor unit of the heating operation, with the indoor cooling and heating switching unit 8 is switched so as to communicate with the indoor heat exchanger 15 and the high-pressure gas pipe 6 _2, the indoor electronic expansion valve 14 is fully opened. Electronic expansion valve 1 of the indoor unit which is stopped
4 is fully closed. The operation of this embodiment will be described below with reference to the outdoor unit 5
Although a will be described as an example, the same applies to other outdoor units.

First, the case where the cooling load is larger than the heating load as a whole of all the indoor units during the simultaneous cooling and heating operation will be described.

The high-temperature and high-pressure refrigerant gas discharged from the compressor 16 of the outdoor unit 5a is distributed by the four-way valves 17 ₁ and 17 ₂ for cooling and heating. Refrigerant gas used for cooling by the four-way valve 17 ₁ is guided to the outdoor heat exchanger 18 _1, the outdoor air heat exchanger and liquid refrigerant (at this time, the outdoor electronic expansion valve 19 ₁ is fully open). This liquid refrigerant passes through the receiver 34, the liquid pipe 3 ₅ of the outdoor unit 5 a, and the common liquid pipe 3,
Described later merges with the liquid refrigerant from the indoor unit during the heating operation flow liquid pipe 3 ₂ half of the indoor unit during the cooling operation, is reduced in pressure by the indoor electronic expansion valve 14, and the indoor air in the indoor heat exchanger 15 Heat exchange to low pressure gas. This low-pressure gas merges with the common low-pressure gas pipe 7 via the cooling / heating switching unit 8 and the low-pressure gas pipe 7 ₂ , and then passes through the low-pressure gas pipe 7 ₅ of the outdoor unit 5a and the accumulator 32 to the suction side of the compressor 16. It returns, is compressed, and is discharged from the compressor 16 again.

On the other hand, the high-temperature high-pressure refrigerant gas used for heating is guided to the high-pressure gas pipe 6 ₅ by the four-way valve 17 ₂ .
Common pressure through the gas pipe 6, flow high-pressure gas pipe 6 ₂ half of the indoor unit during the heating operation, the liquid refrigerant and the indoor air heat exchange in the indoor heat exchanger 15 through the cooling and heating changeover unit 8. The liquid refrigerant electronic expansion valve 14 (fully open), through the liquid pipe 3 _2,
It merges with the liquid refrigerant from the receiver 34 of the outdoor unit in the common liquid pipe 3, and thereafter, it is used for cooling in the indoor unit in the cooling operation as described above to become low-pressure gas, and the compressor passes through the above-described path. Return to the suction side of 16.

Next, when the heating load is larger than the cooling load as a whole of all the indoor units during the simultaneous cooling / heating operation, the following is performed.

The high-temperature high-pressure refrigerant gas discharged from the compressor 16 of the outdoor unit 5a is a four-way valve 17 _2, through a high-pressure gas pipe 6 ₅ passes through the common high-pressure gas pipe 6, the high pressure of the indoor unit in the heating operation diverted to the gas pipe 6 _2, it becomes a liquid refrigerant and the indoor air heat exchange in the indoor heat exchanger 15 via its cooling and heating switching unit 8, the indoor expansion valve 14 (fully open) of the indoor unit, through the liquid pipe 3 ₂ And join at the common liquid pipe 3.

[0029] Here, a portion of the liquid refrigerant diverted to the liquid pipe 3 ₂ indoor units during cooling operation, the indoor heat exchanger 15 indoor air heat exchanger is reduced in pressure by the indoor electronic expansion valve 14 Becomes low-pressure gas, and the cooling / heating switching unit 8 of the indoor unit,
It joins the common low-pressure gas pipe 7 via the low-pressure gas pipe 7 _2, and then returns to the suction side of the compressor 16 through the low-pressure gas pipe 7 ₅ of the outdoor unit 5 a and the accumulator 32.

On the other hand, the other part of the liquid refrigerant passes from the common liquid pipe 3 to the liquid pipe 3 ₅ of the outdoor unit 5a and the receiver 34, is decompressed by the outdoor electronic expansion valve 19 ₂ , and is outdoors by the outdoor heat exchanger 18 ₂ . through the four-way valve 17 ₂ becomes low pressure gas and air and the heat exchanger, back to the suction side of the compressor via the accumulator 32 merges with the low-pressure gas coming from the low-pressure gas pipe 7 ₅ is discharged is compressed again It

When all the indoor units are in the cooling operation, the procedure is as follows. The discharge gas from the compressor 16 is a four-way valve 17 ₁ , 17 ₂
Through the outdoor heat exchangers 18 ₁ and 18 ₂ to exchange heat with the outdoor air to become a liquid refrigerant, and the electronic expansion valves 19 ₁ and 19 fully open.
_{2 through} the receiver 34, the liquid pipe 3 ₅ , and the common liquid pipe 3 to the liquid pipe 3 ₂ of each indoor unit, the pressure is reduced by the indoor electronic expansion valves 14, and the indoor air is exchanged by the indoor heat exchangers 15. The heat is exchanged with the low pressure gas through the respective cooling / heating switching unit 8 and the low pressure gas pipe 7 ₂ to join the common low pressure gas pipe 7, then the low pressure gas pipe 7 _{5 of the} outdoor unit, the accumulator 32 and the compressor 16 Inhaled into.

When all the indoor units are in the heating operation, the procedure is as follows. The discharge gas of the compressor 16 is divided into the high pressure gas pipes 6 ₂ of each indoor unit through the four-way valves 17 ₁ and 17 ₂ , the high pressure gas pipes 6 ₅ and the common high pressure gas pipes 6, and is passed through the respective cooling / heating switching units 8. becomes liquid refrigerant in each of the indoor heat exchanger 15 and indoor air heat exchanger, the electronic expansion valve 14 of the respective fully open, through the liquid pipe 3 ₂ merge into the common liquid pipe 3, then the liquid pipe 3 of the outdoor unit ₅ , the pressure is reduced by the outdoor electronic expansion valves 19 ₁ and 19 ₂ via the receiver 34, and heat is exchanged with the outdoor air by the outdoor heat exchangers 18 ₁ and 18 ₂ into low-pressure gas, and the four-way valves 17 ₁ and 17 ₂ and the accumulator 32 are turned on. After that, it is sucked into the compressor 16.

In the above embodiment, the indoor electronic expansion valve of the stopped indoor unit is closed. Whether to operate all or a part of a plurality of outdoor units, whether to operate both heat exchangers 18 ₁ and 18 ₂ of the operating outdoor unit, or to operate only one of them, etc. The selection combination can be determined according to the required cooling load or heating load. Each indoor expansion valve is controlled so that refrigerant is optimally distributed to each indoor unit according to each indoor load. Flow control valve 3 in the outdoor unit
5, the amount of liquid returned to the compressor 16 can be adjusted to control the compressor discharge gas temperature. Since the heat recovery cycle as described above is formed during the simultaneous cooling and heating operation, the work of the compressor is sufficient to match the difference between the cooling load and the heating load, and energy can be saved.

FIG. 5 is an enlarged view of the means for preventing the unbalance of the amount of oil supplied to the compressor of each outdoor unit in each of the above embodiments. The discharge pipe 20 of the compressor 11 (or 16) of each outdoor unit is connected to the oil separator 21. The oil contained in the high-temperature and high-pressure refrigerant gas discharged from the compressor is separated from the refrigerant by the oil separator 21, and the oil remains in the oil separator 21 and is returned to the compressor through the oil return pipe 22. Similar devices are installed in other outdoor units,
The oil is returned to the compressors respectively, but due to the non-uniformity of the amount of oil returned depending on the operating conditions of the compressors, a shortage of oil supply occurs in a certain compressor, and in some cases seizure of the compressor occurs. In order to prevent this, means for returning and supplying the oil in the oil separator 21 to the plurality of compressors, for example, by connecting the oil equalizing pipe 10 and the pressure equalizing pipe 9 between the oil separators 21 of each outdoor unit, Secure the amount of oil supplied to each compressor.
Thereby, it is possible to prevent the seizure of the compressor caused by the non-uniform refueling amount.

FIG. 6 shows an embodiment of adding an outdoor unit and an indoor unit to the multi air conditioner shown in FIGS. 1 and 2.
The pipes for transporting the refrigerant between the outdoor units 1a, 1b and the indoor units 2a, 2b, 2c, 2d are integrated into two as described above.
To add the outdoor unit 1c and the indoor unit 2e to the multi air conditioner, the gas pipes and liquid pipes of the outdoor unit 1c and the indoor unit 2e are connected to the common gas pipe 4 and the common liquid pipe 3 of the multi air conditioner, respectively. It is sufficient, and there is no need to dispose a new refrigerant transport pipe between the outdoor unit and the indoor unit as in the conventional unit. Also, when the number of outdoor units and indoor units is reduced, it is not necessary to remove the refrigerant transport pipe between the outdoor unit and the indoor unit. Therefore, the number of outdoor units and indoor units of the multi air conditioner can be easily increased or reduced.
When adding or removing the outdoor unit, as shown in the drawing, the pressure equalizing pipe 9,
The oil equalizing pipe 10 is added or deleted.

FIG. 7 is a schematic diagram of piping for transporting refrigerant when the refrigerant transporting pipes of a plurality of outdoor units in the multi-air conditioner of the type shown in FIG. 1 are combined to act as a set of outdoor units. . The liquid pipes of the outdoor units 1a to 1d are connected to the outdoor unit liquid refrigerant header 24, and the gas pipes of the outdoor units 1a to 1d are connected to the outdoor unit gas refrigerant header 25, respectively, so that they act as a set of outdoor units 26 as a whole. ing. Refrigerant transportation between this set of outdoor units and the indoor units 2a to 2f is performed by the header 2
Since the common liquid pipe 3 and the common gas pipe 4 connected to 4, 25 are used, it is possible to reduce the number of refrigerant transport pipes between the outdoor unit and the indoor unit to two.

FIG. 8 shows an indoor unit that constitutes a multi-air conditioner in the multi-air conditioner of the type shown in FIGS. 3 and 4 in which the refrigerant transport pipes between the plurality of outdoor units and the plurality of indoor units are integrated into three. FIG. 27 is a refrigeration cycle diagram of an example in which 27a, 27b, and 27c have a dehumidifying function. The indoor air taken into the indoor unit by the fan 31 is a dehumidifying heat exchanger 29.
Dehumidified by. At this time, since the temperature of the indoor air also drops, the heat exchanger 30 acts as a condenser to heat the indoor air. Thus, dehumidification can be performed without lowering the indoor air temperature.

FIG. 9 is a conceptual diagram showing the arrangement of the refrigerant pipes according to the above-described embodiment of the present invention. Between the plurality of outdoor units and the plurality of indoor units, there are integrated common refrigerant transport pipes (liquid pipes). And a gas pipe, or a liquid pipe, a high-pressure gas pipe, and a low-pressure gas pipe).

FIG. 10 is a refrigeration cycle configuration diagram of another embodiment in which the refrigerant transport pipes between the plurality of outdoor units 36a, 36b and the plurality of indoor units 2a, 2b, 2c are integrated into two. In this embodiment, the refrigerant flowing in the pipe is brought into a gas / liquid two-phase state, so that the two common pipes can simultaneously perform cooling / heating operation. In the following description of the present embodiment, only the refrigerating cycle in the simultaneous cooling and heating operation will be described, and the description in the case of the unified cooling or heating operation will be omitted.

In the simultaneous cooling and heating operation mainly for cooling, the superheated gas refrigerant discharged from the compressor 11 of the outdoor unit is the four-way valve 1.
2, the heat is exchanged in the outdoor heat exchanger 13 to form a high-pressure gas / liquid two-phase refrigerant, which passes through the expansion valve 33 and the flow path control valve 3
Through 7c, it enters through the gas pipe 4 ₁ to the common gas pipe 4,
It reaches the cooling / heating switching unit 38. High pressure two-phase refrigerant enters the cooling and heating switch unit 38 is separated into gas refrigerant and liquid refrigerant in the gas-liquid separator, liquid refrigerant indoor unit in cooling operation through the liquid pipe 3 ₂ indoor units during cooling operation And is decompressed by the expansion valve 14 and heat-exchanged with the indoor air by the indoor heat exchanger 15 to become low-pressure gas. The low-pressure gas refrigerant is the gas pipe 4
₂ to the common gas pipe 3 via the cooling / heating switching unit 38, and then to the outdoor unit via the gas pipe 3 ₁ . The gas refrigerant that has entered the outdoor unit passes through the flow path control valve 37b and passes through the four-way valve 12
Enters the compressor 11 and is compressed again to become a superheated refrigerant and is discharged.

On the other hand, the gas refrigerant separated in the cooling and heating switch units 38 is sent to the indoor unit during the heating operation through the gas pipe 4 ₂ indoor units during heating operation, the indoor air heat at the heat exchanger 15 It is exchanged to become a liquid refrigerant, and enters the liquid pipe 3 ₂ via the expansion valve. Liquid refrigerant enters from the liquid pipe 3 ₂ to cooling and heating switch units 38 is mixed with the liquid refrigerant separated in the gas-liquid separator, used for cooling becomes low-pressure gas refrigerant in the indoor unit in cooling operation, as in the Return to the compressor 11 of the outdoor unit by the route of.

In the case of simultaneous heating / cooling simultaneous operation, the superheated refrigerant discharged from the compressor 11 causes the four-way valve 12,
Flow path control valve 37d, the gas pipe 4 _1, a common gas pipe 4 above,
Enter the cooling / heating switching unit 38. The gas refrigerant that has entered the gas pipe 4 ₂ of the indoor unit that is in the heating operation from the cooling / heating switching unit 38 is sent to the indoor unit that is in the heating operation, and heat-exchanges with the indoor air in the heat exchanger 15 therein to become a liquid refrigerant. , Its expansion valve 14,
Enters the liquid pipe 3 ₂ as cooling and heating switch units 38. Some of the liquid refrigerant enters the cooling and heating switch units 38 is sent to the indoor unit in cooling operation enters the liquid pipe 3 ₂ indoor units in the cooling operation, is decompressed by the expansion valve 14, the heat exchanger 15 in indoor air is heat-exchanged becomes low-pressure gas enters a heating and cooling switching unit 38 through the gas pipe 4 _2. Containing gas refrigerant to the cooling and heating switch unit 38 through the common liquid pipe 3 with remaining liquid refrigerant in cooling and heating switch units 38, enters the outdoor unit from the liquid pipe 3 _1, reduced in pressure across expansion valve 33 from the flow path control valve 37a The heat is exchanged in the outdoor heat exchanger 13 to become a gas refrigerant. Next, this gas refrigerant enters the compressor 11 through the four-way valve 12, is compressed again, and is discharged as superheated gas.

FIG. 11 shows an embodiment of the oil supply amount imbalance prevention means when the compressor oil is supplied by the external oil supply system. In this embodiment, by adopting the external oil supply method, it is possible to prevent oil from accumulating inside the compressor that is not operating, and prevent seizure of the compressor due to imbalance of the oil supply amount. In FIG. 11, the superheated refrigerant discharged from the compressor 11 in the outdoor unit passes through the discharge pipe 20 and enters the oil separator 40. Where it is separated into oil and refrigerant,
The separated refrigerant is sent to the indoor unit or the outdoor heat exchanger through the discharge pipe 41 and used for cooling and heating. On the other hand, the oil in the oil separator 40 is supplied to the compressor 11 through the oil supply pipe 39. Since the pressure equalizing pipe 9 and the oil equalizing pipe 10 are communicated between the oil separators 40 of each outdoor unit, nonuniformity of the oil reservoir does not occur between the oil separators 40. As described above, seizure of the compressor due to uneven supply of oil can be prevented.

The above-described common pipes of the present invention, which are integrated into two or three pipes, may be a bundle of two or three separate pipes, or two pipes that extend inside each other. It may be constituted by one tube having three or three channels.

[0045]

As described above, according to the invention of claim 1, in a multi-air conditioner including a plurality of outdoor units and a group of indoor units, one common liquid pipe and one common gas pipe are provided outdoors. By sharing it as a pipe for transporting the refrigerant between the machine and the indoor unit, it is possible to use only two pipes for transporting the refrigerant, which is the longest and requires complicated installation work.

When adding an indoor unit and an outdoor unit,
It is not necessary to newly install a pipe for transporting the refrigerant, and the indoor unit is connected to one end where the liquid pipes of each indoor unit of the common liquid pipe are integrated, or the outdoor unit is connected to the gas pipe of each outdoor unit of the common gas pipe. Simply connect each to one end. Therefore, the amount of pipes used can be reduced as compared with the case where a plurality of pipes for transporting the refrigerant are provided according to the number of indoor units and outdoor units, and the piping work required at the time of expansion can be simplified by this amount.

Further, the indoor expansion valve of the indoor unit whose operation is stopped is closed, and the indoor expansion valves of the other indoor units are controlled according to each indoor load, so that one liquid pipe or one gas pipe is shared. However, it is possible to properly distribute the refrigerant to each indoor unit, and it is possible to operate with a high degree of flexibility while sufficiently responding to the expansion and reduction of the number of indoor units.

Therefore, since each outdoor unit and each indoor unit act in association with one group of outdoor units and one group of indoor units, they can be used as an air conditioner after simplifying piping work when they are added later. The possible capacity range can be widened.

According to the third aspect of the invention, when increasing the capacity of the air conditioner as a whole, it is not necessary to newly install a pipe for transporting the refrigerant even if the outdoor unit is additionally installed. The piping work can be simplified. Moreover, since the operation of each outdoor unit including the added outdoor unit is controlled as a set, it is possible to support a wide and fine capacity.

According to the invention of claim 4, since the outdoor unit is connected to the refrigerant pipe of one system through the header, no change is made to other outdoor units when adding or reducing the outdoor unit. It is even easier to amplify and reduce the number of outdoor units without being accompanied by this.

According to the fifth aspect of the present invention, the number of pipes is reduced by using a single common refrigerant pipe as a pipe for transporting the refrigerant from the plurality of outdoor units to the plurality of indoor units. The cooling or heating operation of the machine can be independently performed, that is, the simultaneous cooling and heating operation can be enabled.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment of a multi-air conditioner according to the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of another embodiment of the multi-air conditioner according to the present invention.

FIG. 4 is a configuration diagram of a refrigeration cycle according to another embodiment of the present invention.

FIG. 5 is a diagram showing an oil supply amount equalizing means between compressors of the outdoor units.

FIG. 6 is an explanatory diagram of adding an outdoor unit and an indoor unit according to the embodiment of the present invention.

FIG. 7 is a diagram showing an embodiment in which a liquid pipe and a gas pipe of each outdoor unit are collected in a header.

FIG. 8 is a refrigeration cycle diagram of another embodiment of the present invention having a dehumidifying function.

FIG. 9 is a diagram showing a concept of integrating the refrigerant transport pipes of the present invention.

FIG. 10 is a configuration diagram of a refrigerating cycle according to another embodiment of the present invention.

FIG. 11 is a diagram showing another means for equalizing the amount of oil supply between the compressors of the outdoor units.

[Explanation of symbols]

 1a-1d, 5a-5d, 36a, 36b ... Outdoor unit 2a-2f ... Indoor unit 3 ... Common liquid pipe 4 ... Common gas pipe 6 ... Common high pressure gas pipe 7 ... Common low pressure gas pipe 9 ... Equalizing pipe 10 ... Equalizing pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toshiyuki Hojo, Toshiyuki Hojo, 390 Muramatsu, Shimizu, Shizuoka Prefecture, Hitachi, Ltd., Air Conditioning Systems Division (72) Inventor, Keiji Tanaka, 390, Muramatsu, Shimizu, Hitachi, Ltd., Air Conditioning Systems, Hitachi, Ltd. Inside (72) Inventor Oguni Kensaku Machinery Research Institute, Hiritsu Manufacturing Co., Ltd., 502 Jinrachicho, Tsuchiura City, Ibaraki Prefecture (72) Inventor Fumihiko Kitani 390 Muramatsu, Shimizu, Shizuoka Hitachi Air Conditioning Systems Division, Hitachi Ltd.

Claims (5)

[Claims] 1. A plurality of indoor units, a plurality of outdoor units,
In a multi-air conditioner having a liquid pipe and a gas pipe provided in each indoor unit and each outdoor unit, and an indoor expansion valve provided in each indoor unit, a plurality of the gas pipes of each outdoor unit are integrated. Then, the other end side is connected to one end side by consolidating one common gas pipe connected to each indoor unit side and the liquid pipes of each of the plurality of outdoor units, The other end is provided with one common liquid pipe connected to each indoor unit side, and the one common gas pipe and the one common liquid pipe are connected between the outdoor unit and the indoor units during operation. The indoor expansion valve of the indoor unit, which is shared as a pipe for transporting the refrigerant and stops the operation, is closed to prevent the refrigerant from flowing from the one common liquid pipe to the indoor unit that stops the operation, and The indoor expansion valve of the indoor unit is controlled according to each indoor load. Air conditioning. 2. The multi-air conditioner according to claim 1, wherein each of the indoor units to be operated is integrally operated as cooling or heating. 3. The multi-air conditioner according to claim 1, wherein when adding an outdoor unit, the gas pipe of the outdoor unit to be added is connected to the one end of the one common gas pipe, and the added outdoor unit is connected. Including, the one common gas pipe is shared as a pipe for transporting the refrigerant between each of the outdoor units and each of the indoor units at the time of operation, and operation control is performed for each of the outdoor units as a set. Air conditioner. 4. A plurality of outdoor units, a plurality of indoor units,
In a multi-air conditioner having refrigerant pipes provided in each of the outdoor units and the indoor units, a header that aggregates the refrigerant pipes of the outdoor units, the header is connected to one end, the other end to the indoor unit side When the outdoor unit is expanded by including the connected 1-system refrigerant pipe, the outdoor unit to be expanded is connected to the header, and the 1-system refrigerant pipe including the expanded outdoor unit A multi-air conditioner characterized by being shared as a pipe for transporting a refrigerant between an outdoor unit and each of the indoor units, and controlling the operation of each of the outdoor units as one set including the added outdoor unit. 5. A plurality of indoor units, a plurality of outdoor units,
In a multi-air conditioner having each of the indoor units and a refrigerant pipe provided in each of the outdoor units, the refrigerant pipes of each of the plurality of outdoor units are aggregated and connected to one end side thereof, and the other end side is each indoor unit 1 connected to the side
A multi-air conditioner, comprising: a plurality of common refrigerant pipes, wherein the inside of the common refrigerant pipe is in a gas / liquid two-phase state during operation.