JPH07104075B2 - Air conditioner - Google Patents

Description

TECHNICAL FIELD The present invention relates to a multi-chamber heat pump air conditioner in which a plurality of indoor units are connected to one heat source unit, and particularly for each indoor unit. The present invention relates to an air conditioner capable of selectively performing heating and cooling, cooling in one indoor unit, and heating in the other indoor unit at the same time.

[Conventional technology]

Conventionally, a heat pump type air conditioner in which a plurality of indoor units are connected to one heat source unit by two pipes of a gas pipe and a liquid pipe and a heating / cooling operation is common, and all the indoor units are heated, Alternatively, they are all configured to perform cooling.

[Problems to be Solved by the Invention]

Since the conventional multi-room heat pump type air conditioner is configured as above, all indoor units operate only for cooling or heating, so heating is performed where cooling is required, or conversely heating. There was a problem that the air conditioning was done where it was needed.

In particular, when installed in a large building, the load of air conditioning is significantly different between the interior section and the perimeter section, or the office room such as the general office and the computer room, which is a particular problem.

The present invention has been made to solve the above problems, and a plurality of indoor units are connected to one heat source unit, and cooling and heating are selectively performed for each indoor unit, and one of the indoor units is provided. When installed in a large building so that the indoor unit can be used for cooling and the other indoor unit for heating at the same time, the interior and perimeter parts, or the general office and computer rooms have been converted to office automation. An object of the present invention is to obtain a multi-room heat pump type air conditioner capable of coping with different air-conditioning loads even if the air-conditioning loads differ significantly between rooms.

[Means for Solving the Problem] One heat source device including a compressor, a switching valve, a heat source device side heat exchanger, and the like, and a plurality of indoor units each having an indoor heat exchanger are provided. The one connected via the second connection pipe, wherein one of the indoor heat exchangers of the plurality of indoor units is switchably connected to the first connection pipe or the second connection pipe. A first branch part, a second branch part connected to the other of the indoor heat exchangers of the plurality of indoor units and connected to the second connection pipe, and the second connection A pipe branch portion that branches from the pipe to the pipe that reaches the first branch portion, and a pipe path that connects the pipe branch portion and the other of the indoor unit side heat exchangers is provided in the middle of the pipe. A flow rate control device for controlling a flow rate, the second branch portion and the first connection pipe are connected to a third flow path. The bypass pipe connected via a control device, the bypass pipe between the third flow control device and the first connection pipe, and the second connection pipe on the indoor unit side include the second pipe. A heat exchange part for exchanging heat between the connection pipe and the pipe extending to the pipe branching part and the first and second connection pipes are provided, and by switching the direction of the flowing refrigerant, it is always possible during operation. And a connection pipe switching device for making the first connection pipe interposed between the heat source unit and the indoor unit have a low pressure and the second connection pipe have a high pressure.

Also, the first flow rate control device is connected to the other of the indoor heat exchangers of the indoor units in close proximity to each other, and the second flow rate control device is connected to the second branch pipe between the pipe branch portion and the second branch portion. And a bypass pipe, the pipe branch part, and the second pipe as a heat exchange part.
It is provided with a first heat exchanging portion for exchanging heat with the pipe connecting the flow control device.

Further, as a heat exchange part, a bypass pipe between the third flow rate control device and the first connection pipe, and a confluence part and an indoor side connection of the indoor side connection pipe connecting each indoor unit and the second branch part. It is provided with second and third heat exchanging portions for respectively exchanging heat with the pipe.

[Action]

In the present invention, in the case of mainly cooling in the simultaneous heating and cooling operation, the refrigerant that has undergone an arbitrary amount of heat exchange in the heat source side heat exchanger and is sent to the second connection pipe is used in the room that is going to be cooled in the following route. Supplied to the machine. That is, the second
From the pipe branch portion of the connection pipe of No. 2 to the refrigerant that flows into the second branch portion, and from the pipe branch portion to the indoor unit that is going to be heated through the first branch portion, by exchanging heat and heating. After the condensed and liquefied refrigerant merges at the second branch,
It is supplied to each indoor unit.

Further, in the case of only the cooling operation, the refrigerant having undergone heat exchange in the heat source side heat exchanger is supplied from the pipe branch portion to each indoor unit to be cooled via the second branch portion.

As described above, in the case of cooling mainly, in the case of only cooling operation,
In any case, the refrigerant is cooled in the heat exchange section,
In the heat exchange section, the liquid refrigerant is distributed and flows into each room to be cooled after being sufficiently subcooled before being distributed to the indoor unit to be cooled, so that the distributability of the liquid refrigerant is improved. , Reliability is improved.

Further, as described above, in the circulation process of the refrigerant supplied to the indoor unit about to be cooled, both in the case of mainly cooling and only in the cooling operation, the first heat exchange section cools the
Even when the refrigerant flowing through the second connection pipe is in a gas-liquid two-phase state, the refrigerant is always sufficiently subcooled at the inlet of the second flow rate control device, and the flow of the refrigerant in the second flow rate control device and Flow rate control becomes easy.

Further, since it is cooled by the second and third heat exchange parts, it is distributed and flown into the indoor unit after being sufficiently subcooled.
Distributability of the liquid refrigerant is improved, a subcool at the inlet of the first flow rate control device can be secured, and reliability is improved.

〔Example〕

 Examples of the present invention will be described below.

FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to an embodiment of the present invention. Further, FIGS. 2 to 4 show the operation state during the cooling and heating operation in the embodiment of FIG. 1, and FIG. 2 is an operation state diagram only for cooling or heating, FIGS. 3 and 4. Shows the operation of the cooling and heating simultaneous operation. Fig. 3 shows the heating main body (when the heating operation capacity is larger than the cooling operation capacity) and Fig. 4 shows the cooling main body (when the cooling operation capacity is larger than the heating operation capacity). It is a driving operation state diagram shown. FIG. 5 is an overall configuration diagram centering on the refrigerant system of the air conditioner of another embodiment of the present invention.

In this embodiment, a case where three indoor units are connected to one heat source unit will be described, but the same applies when two or more indoor units are connected.

In FIG. 1, (A) is a heat source device, (B), (C),
As will be described later, (D) is an indoor unit connected in parallel with each other and has the same configuration. (E) is, as will be described later, a first branch part, a second flow rate control device, a second branch part, a gas-liquid separation device, a heat exchange part, a third flow rate control device, and a fourth flow rate control device. Repeater with built-in.

(1) is a compressor, (2) is a four-way switching valve that switches the refrigerant flow direction of the heat source unit, (3) is the heat source unit side heat exchanger, (4)
Is an accumulator, which is connected to the above devices (1) to (3) to form a heat source unit (A). (5) is three indoor heat exchangers, (6) is a thick first connecting pipe connecting the four-way switching valve (2) of the heat source unit (A) and the relay unit (E), (6b), ( 6
c) and (6d) are indoor units (B), (C), (D), respectively.
The indoor heat exchanger (5) and the relay (E) are connected to
The first connection pipe on the indoor unit side corresponding to the connection pipe (6) of (1), (7) is the first connection pipe for connecting the heat source unit side heat exchanger (3) and the relay unit (E) of the heat source unit (A) With a second connection pipe thinner than the connection pipe of No. 1, one end is connected to the heat source unit side heat exchanger (3), and the other end is inside the second branching unit (11) so that a second unit on the indoor unit side to be described later is provided. It is connected to the junction of the connection pipes (7b), (7c), and (7d). (7b), (7c) and (7d) respectively connect the indoor side heat exchanger (5) of the indoor units (B), (C) and (D) and the repeater (E), and form a second connecting pipe. The second connection pipe on the indoor unit side corresponding to (7), (8) the first connection pipe (6a), (6b), (6c) on the indoor unit side, the first connection pipe (6) Alternatively, a three-way switching valve (9) switchably connected to the second connection pipe (7) side is connected close to the indoor heat exchanger (5), and during cooling, the indoor heat exchanger (5) The first flow rate control device is controlled by the superheat amount on the outlet side of the air conditioner and the subcool amount during heating, and is connected to the second connection pipes (7b), (7c), (7d) on the indoor unit side. (10) is the first connection pipe (6b), (6c), (6d) on the indoor unit side,
A first one comprising a three-way switching valve (8) switchably connected to the first connection pipe (6) or the second connection pipe (7) side.
The branch part (11) is the second connection pipe (7b) on the indoor unit side,
(7c), (7d), and a second branch portion including the second connecting pipe, and (12) is a pipe branching from the second connecting pipe (7) to reach the first branch portion (10). In the gas-liquid separation device provided at the pipe branch part, the gas phase part is connected to the first port (8a) of the three-way switching valve (8), and the liquid phase part is connected to the second branch part (11). It is connected. (13) is a second flow control device that is connected between the gas-liquid separator (12) and the second branch (11) and is openable and closable, and (14) is the second branch (11) and the above A bypass pipe connecting to the first connection pipe (6), (15) a third flow control device provided in the middle of the bypass pipe (14), (16
b), (16c) and (16d) are provided in the bypass pipe (14) downstream of the third flow rate control device (15), and the second connection on the indoor unit side of the second branch section (11). Piping (7b),
A third heat exchange section (16a) for respectively exchanging heat with (7c) and (7d) is provided downstream of the third flow rate control device (15) in the bypass pipe (14), and Second connection pipes (7b), (7c) on the indoor unit side in the branch part (11) of
A second heat exchanging part for exchanging heat with the confluence part of (7d),
(19) is provided in the bypass pipe (14) downstream of the third flow rate control device (15) and downstream of the second heat exchange section (16a), and the gas-liquid separation device (12) and the second flow rate control device are provided. A first heat exchange section for exchanging heat with a pipe connecting to the device (13),
(17) is a fourth flow rate control device which is connected between the second branch portion (11) and the first connection pipe (6) and which can be opened and closed freely.

(32) is a third check valve provided between the heat source unit side heat exchanger (3) and the second connection pipe (7), and the heat source unit side heat exchanger (3) To allow the refrigerant to flow only to the second connecting pipe (7). (33) is a fourth check valve provided between the four-way switching valve (2) of the heat source unit (A) and the first connecting pipe (6), and is the first connecting pipe. The refrigerant is allowed to flow only from (6) to the four-way switching valve (2). (34) is a fifth check valve provided between the four-way switching valve (2) of the heat source unit (A) and the second connecting pipe (7), and the four-way switching valve (2) ) To the second connecting pipe (7) only.
(35) is a sixth check valve provided between the heat source unit side heat exchanger (3) and the first connection pipe (6), and from the first connection pipe (6) Refrigerant flow is allowed only to the heat source side heat exchanger (3). The third check valve (32) to the sixth check valve (35) constitute a connection pipe switching device (40).

An embodiment of the present invention configured as above will be described.

First, the case of only the cooling operation will be described with reference to FIG.

That is, as shown by the solid arrow in FIG.
High-temperature and high-pressure refrigerant gas discharged from the four-way switching valve (2)
Through the heat source side heat exchanger (3) to be condensed, and then the third check valve (32), the second connecting pipe (7), the gas-liquid separation device (12), the third 2 in order of the flow rate control device (13), and further through the second branch part (11) and the second connection pipes (7b), (7c), (7d) on the indoor unit side, and each indoor unit (B ),
It flows into (C) and (D). And each indoor unit (B),
The refrigerant flowing into (C) and (D) is controlled by the amount of superheat at the outlet of each indoor heat exchanger (5).
The pressure is reduced to a low pressure by the flow control device (9), and the indoor heat exchanger (5) exchanges heat with the indoor air to evaporate, gasify, and cool the room. Then, the refrigerant in the gas state is used for the first connection pipes (6b), (6c), (6) on the indoor unit side.
d), through the three-way switching valve (8), the first branch (10),
A circulation cycle that is sucked into the compressor (1) via the first connection pipe (6), the fourth check valve (33), the four-way switching valve (2) of the heat source device (A), and the accumulator (4). Configure
Perform cooling operation. At this time, the first port (8a) of the three-way switching valve (8) is closed, and the second port (8b) and the third port (8c) are open. At this time, the refrigerant is the first connection pipe (6).
Is low pressure and the second connection pipe (7) is high pressure, so that it inevitably flows to the third check valve (32) and the fourth check valve (33).

Further, during this cycle, the second flow rate control device (13)
A part of the refrigerant that has passed through enters the bypass pipe (14), is depressurized to a low pressure by the third flow rate control device (15), and is cooled by the third heat exchange parts (16b), (16c), (16d). Between the second connection pipes (7b), (7c), and (7d) on each indoor unit side, the second heat exchange section (16a) is provided on each indoor unit side of the second branch section (11). Between the second connection pipes (7b), (7c), and the confluence of (7d), and with the refrigerant flowing into the second flow rate control device (13) at the first heat exchange part (19). The refrigerant that has undergone heat exchange between the two and enters into the first connection pipe (6) and the fourth check valve (33) enters the four-way switching valve (2) and the accumulator (4), and then the compressor (1). Inhaled into. On the other hand, the first, second and third
Heat exchange part (19), (16a), (16b), (16c), (16
The refrigerant in the second branch portion (11) that has been heat-exchanged and cooled in d) and is sufficiently subcooled flows into the indoor units (B), (C), (D) that are about to be cooled.

Next, the case of only the heating operation will be described with reference to FIG. That is, as shown by the dotted arrow in FIG. 2, the high-temperature high-pressure refrigerant gas discharged from the compressor (1) passes through the four-way switching valve (2), the fifth check valve (34), and the second connection. Pass through the pipe (7) and the gas-liquid separation device (12), and then the first branch (1
0), three-way selector valve (8), first connection pipe (6
b), (6c), (6d) in this order, each indoor unit (B),
It flows into (C) and (D), heat-exchanges with room air, condenses into liquefaction, and heats the room. Then, the refrigerant in the liquid state passes through the first flow rate control device (9) which is controlled by the subcool amount at the outlet of each indoor heat exchanger (5), and the second connection pipe (on the indoor unit side) 7b), (7c), and (7d) flow into the second branch portion (11) and merge, and further pass through the fourth flow rate control device (17), where the first flow rate control device (9) is present. Alternatively, the pressure is reduced to a low-pressure two-phase state by the fourth flow control device (17). Then, the refrigerant decompressed to a low pressure flows into the heat source side heat exchanger (3) from the sixth check valve (35) through the first connecting pipe (6), exchanges heat, and evaporates. A gas cycle is formed, and a four-way switching valve (2) and an accumulator (4) are taken into the compressor (1) to form a circulation cycle to perform a heating operation. At this time, the second port (8b) of the three-way switching valve (8)
Is closed, and the first opening (8a) and the third opening (8c) are open. At this time, the refrigerant is inevitably low in the first connecting pipe (6) and high in the second connecting pipe (7), so that the fifth check valve (34) and the sixth check valve (inevitably). 35).

The case of mainly heating in the simultaneous cooling and heating operation will be described with reference to FIG. Here, a case will be described in which two indoor units (B) and (C) are about to heat and one indoor unit (D) is about to cool.

That is, as shown by the solid line arrow in FIG. 3, the compressor (1)
The high-temperature high-pressure refrigerant gas discharged from the four-way switching valve (2),
The fifth check valve (34), the second connecting pipe (7), the relay device (E), the gas-liquid separator (12), and the first branch (10), The three-way switching valve (8), the indoor unit-side first connecting pipes (6b), (6c) are passed in this order and flow into the indoor units (B) and (C) that are going to be heated, and the indoor heat exchanger ( In 5), heat is exchanged with room air to be condensed and liquefied, and the room is heated. Then, the refrigerant in the liquid state is controlled by the subcool amount at the outlet of each indoor heat exchanger (5), passes through the first flow rate control device (9) in a substantially fully opened state, and is slightly decompressed to the second branch. Flows into the section (11). Then, a part of this refrigerant passes through the second connection pipe (7d) on the indoor unit side and enters the indoor unit (D) that is about to be cooled, depending on the superheat amount at the outlet of the indoor heat exchanger (5). After entering the controlled first flow rate control device (9) and being decompressed, it enters the indoor heat exchanger (5) to exchange heat and evaporate into a gas state to cool the room and cool the three-way switching valve ( 1st through 8)
Into the connecting pipe (6).

On the other hand, the other refrigerant passes through the open / close fourth flow rate control device (17) controlled by the high pressure of the second connection pipe (7) and the intermediate pressure value of the second branch portion (11) to cool the air. The sixth check valve (35) of the heat source unit (A) merges with the refrigerant that has passed through the indoor unit (D) to be tried, and passes through the thick first connection pipe (6).
It flows into the heat source unit side heat exchanger (3), exchanges heat, evaporates and becomes a gas state. Then, the refrigerant constitutes a circulation cycle in which it is drawn into the compressor (1) through the four-way switching valve (2) of the heat source device and the accumulator (4), and performs heating-main operation.
At this time, the indoor heat exchanger (5) of the indoor unit (D) to be cooled
The difference between the evaporating pressure of 1 and the evaporating pressure of the heat source side heat exchanger (3) is reduced because the pressure is switched to the thick first connecting pipe (6). At this time, the second port (8b) of the three-way switching valve (8) connected to the indoor units (B) and (C) is closed, and the first port (8a) and the third port (8c) are opened. The first port (8a) of the three-way switching valve (8) connected to the indoor unit (D) is closed, and the second port (8b) and the third port (8c) are open. Further, at this time, the refrigerant inevitably has a low pressure in the first connecting pipe (6) and a high pressure in the second connecting pipe (7), so that the fifth check valve (34) and the sixth check valve ( 35).

In addition, during this cycle, a part of the liquid refrigerant is the second connection pipes (7b), (7c) on the indoor unit side of the second branch section (11),
It enters the bypass pipe (14) from the confluence part of (7d), is depressurized to a low pressure by the third flow rate control device (15), and is in each room in the third heat exchange parts (16b), (16c), (16d). The second heat exchange section (16a) between the second connection pipes (7b), (7c), and (7d) on the machine side, and the second branch section (11) on the indoor unit side of the second section. The heat is exchanged between the connecting pipes (7b), (7c) and (7d) of the connecting pipes, and the evaporated refrigerant enters the first connecting pipe (6) and the heat source unit (A) is connected to the sixth connecting pipe. To the check valve (35) and the heat exchanger (3) on the heat source unit side to exchange heat and evaporate to become a gas state. Then, this refrigerant is drawn into the compressor (1) through the four-way switching valve (2) of the heat source unit (A) and the accumulator (4). On the other hand, the second and third heat exchange parts (16a), (16
The refrigerant in the second branch portion (11), which is cooled by the heat exchange in (b), (16c) and (16d) and is sufficiently subcooled, flows into the indoor unit (D) that is about to be cooled. A case of mainly cooling in the cooling / heating simultaneous operation will be described with reference to FIG. Here, a case will be described in which two indoor units (B) and (C) are about to cool and one indoor unit (D) is about to heat.

That is, as shown by the solid arrow in FIG. 4, the compressor (1)
The discharged high-temperature high-pressure refrigerant gas is heat-exchanged in the heat-source-unit-side heat exchanger (3) by an arbitrary amount to become a two-phase high-temperature high-pressure gas,
It is sent to the gas-liquid separation device (12) of the relay machine (E) through the third check valve (32) and the second connection pipe (7). And
Here, the gaseous refrigerant and the liquid refrigerant are separated, and the separated gaseous refrigerant is the first branch portion (10), the three-way switching valve (8),
It passes through the first connection pipe (6d) on the indoor unit side, flows into the indoor unit (D) that is going to be heated, and exchanges heat with the indoor air in the indoor heat exchanger (5) to be condensed and liquefied. To heat up. Further, it is controlled by the amount of subcool at the outlet of the indoor heat exchanger (5), slightly depressurized through the first flow rate control device (9) in a substantially fully opened state, and then flows into the second branch portion (11). On the other hand, the remaining liquid refrigerant separated by the gas-liquid separator (12) is a second openable and closable controlled by the high pressure of the second connecting pipe (7) and the intermediate pressure value of the second branch (11). Flows into the second branch portion (11) through the flow rate control device (13) and merges with the refrigerant that has passed through the indoor unit (D) to be heated. Then, the second branch portion (11) and the second connection pipes (7b) and (7c) on the indoor unit side are passed in this order to flow into the indoor units (B) and (C). And each indoor unit (B),
The refrigerant flowing into (C) is depressurized to a low pressure by the first flow rate control device (9) controlled by the superheat amount at the outlet of the indoor unit side heat exchanger (5), and then the indoor side heat exchanger (5). Flows into the room and is heat-exchanged with the room air to evaporate and gasify to cool the room. Further, the refrigerant in the gas state passes through the first connection pipes (6b) and (6c) on the indoor unit side, the three-way switching valve (8), and the first branch portion (10) to make the first connection. The pipe (6), the fourth check valve (33), the four-way switching valve (2) of the heat source unit (A), the accumulator (4), and the compressor (1).
It forms a circulation cycle that is sucked into and performs cooling-main operation. At this time, the second port (8b) and the third port (8c) of the three-way switching valve (8) connected to the indoor units (B) and (C) are open, and the first port (8a) is closed. The first port (8a) and the third port (8c) of the three-way switching valve (8) connected to the indoor unit (D) are open, and the second port (8b) is closed. Further, at this time, the refrigerant has a low pressure in the first connecting pipe (6) and a high pressure in the second connecting pipe (7), so that the third check valve (32) and the fourth check valve are inevitable. Distribution to (33).

Further, during this cycle, part of the liquid refrigerant is the second connection pipes (7b), (7c) on the indoor unit side of the second branch section (11),
It enters the bypass pipe (14) from the confluence part of (7d), is depressurized to a low pressure by the third flow rate control device (15), and is in each room in the third heat exchange parts (16b), (16c), (16d). The second heat exchange section (16a) between the second connection pipes (7b), (7c), and (7d) on the machine side, and the second branch section (11) on the indoor unit side of the second section. Between the connection pipes (7b), (7c), and (7d) of the connection pipe, and further between the first heat exchange unit (19) and the refrigerant flowing into the second flow rate control device (13). The refrigerant that has undergone heat exchange and evaporated enters the first connection pipe (6), and the fourth check valve (33) of the heat source unit (A), the four-way switching valve (2) of the heat source unit (A), and the accumulator. After (4), it is sucked into the compressor (1). on the other hand,
First, second and third heat exchange parts (19), (16a), (16
The refrigerant in the second branch part (11), which is cooled by heat exchange in (b), (16c) and (16d) and is sufficiently subcooled, flows into the indoor units (B) and (C) that are about to be cooled. .

In the above embodiment, the three-way switching valve (8) is provided and the first connection pipes (6b), (6c), (6d) on the indoor unit side and the first connection pipe (6) or the second connection pipe (6). Although it is switchably connected to the connection pipe (7), as shown in FIG. 5, two solenoid valves (30), (31) and other on-off valves are provided and switchably connected as described above. Also has the same effect.

[Advantages of the Invention] An air conditioner of the present invention includes one heat source unit including a compressor, a switching valve, a heat source unit side heat exchanger, and the like, and a plurality of indoor units each having an indoor side heat exchanger. , Connected via the first and second connecting pipes, one of the indoor heat exchangers of the plurality of indoor units can be switched to the first connecting pipe or the second connecting pipe. A first branch part connected to the second branch part connected to the other of the indoor heat exchangers of the plurality of indoor units and connected to the second connection pipe; Provided in the middle of a pipe connecting the pipe branching part branching from the second connecting pipe to the pipe reaching the first branching part, and the pipe branching part and the other of the indoor unit side heat exchangers. And a flow rate control device for controlling the flow rate of the refrigerant, the second branch portion and the first connection arrangement. A bypass pipe connected via a third flow control device, the bypass pipe between the third flow control device and the first connection pipe, and the second connection pipe on the indoor unit side. By including a heat exchanging part for exchanging heat between the pipe connecting the second connecting pipe and the pipe branching portion and the first and second connecting pipes, and switching the direction of the flowing refrigerant. During operation, a connection pipe switching device for constantly setting the first connection pipe interposed between the heat source unit and the indoor unit to a low pressure and setting the second connection pipe to a high pressure is provided. Therefore, it is possible to selectively cool a plurality of indoor units, one indoor unit can perform cooling, and the other indoor unit can simultaneously perform heating, and the liquid refrigerant is used in the heat exchange unit to cool the indoor unit. Since the subcool is sufficiently applied before being distributed to the machine, the liquid refrigerant is distributed and flows into each room that is going to be cooled, so that the distributability of the liquid refrigerant is improved and the reliability is improved.

Also, the first flow rate control device is connected to the other of the indoor heat exchangers of the indoor units in close proximity to each other, and the second flow rate control device is connected to the second branch pipe between the pipe branch portion and the second branch portion. And a bypass pipe, the pipe branch part, and the second pipe as a heat exchange part.
Since the first heat exchange section for exchanging heat with the pipe connecting the flow rate control device of No. 1 is provided, the second connection is provided only in the cooling operation and in the case of mainly cooling in the heating / heating simultaneous operation. Even when the refrigerant flowing through the pipe is in the two-phase state, it is cooled in the first heat exchange section, so that the refrigerant is always a sufficiently subcooled liquid refrigerant at the inlet of the second flow rate control device, and The circulation and flow rate control of the refrigerant of the second flow rate control device are facilitated.

Further, as a heat exchange part, a bypass pipe between the third flow rate control device and the first connection pipe, and a confluence part and an indoor side connection of the indoor side connection pipe connecting each indoor unit and the second branch part. Since the second and third heat exchanging portions for respectively exchanging heat with the pipes are provided, the liquid refrigerant is distributed to the indoor units which are going to be cooled in the second and third heat exchanging portions. Since the subcool is sufficiently attached before it is distributed and flown into each room that is going to be cooled, the distributability of the liquid refrigerant is improved, and the subcool at the inlet of the first flow rate control device can be secured, and the reliability is improved. .

[Brief description of drawings]

FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air conditioner according to an embodiment of the present invention. FIG. 2 is an operation state diagram of only the cooling or heating of the embodiment shown in FIG. 1, and FIG. 3 is a heating main body of the embodiment shown in FIG. 1 (when the heating operation capacity is larger than the cooling operation capacity. ) Operation state diagram, FIG. 4 is an operation state diagram of the cooling main body (when the cooling operation capacity is larger than the heating operation capacity) of the embodiment shown in FIG.
The figure is an overall configuration diagram centering on a refrigerant system of an air conditioner according to another embodiment of the present invention. In the figure, (A) is a heat source device, (B), (C), (D)
Is an indoor unit with the same configuration, (E) is a repeater,
(1) is a compressor, (2) is a switching valve, (3) is a heat source unit side heat exchanger, (4) is an accumulator, (5) is an indoor side heat exchanger, and (6) is a first connecting pipe. , (6b), (6c), (6
d) is the second connection pipe on the indoor unit side, (7b), (7c), (7
d) is the second connection pipe on the indoor unit side, (8) is a three-way switching valve, (9) is the first flow control device, (10) is the first branch part, and (11) is the second branch part. Part, (12) is a gas-liquid separator,
(13) is the second flow control device, (14) is bypass piping,
(15) is a third flow rate control device, (16a), (16b), (16
c) and (16d) are the second and third heat exchange parts, and (19) is the first
Heat exchange part, (17) is a fourth flow rate control device, (30),
(31) is an on-off valve such as a solenoid valve, (32) is a third check valve,
(33) is the fourth check valve, (34) is the fifth check valve, (35)
Is a sixth check valve, and (40) is a connection pipe switching device. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. A compressor 1, a switching valve 2, a heat source unit side heat exchanger 3
A plurality of indoor units B each having one heat source unit A composed of
C and D are connected via first and second connection pipes 6 and 7, and one of the indoor heat exchangers 5 of the plurality of indoor units B, C and D is connected to the first To the other of the indoor heat exchangers 5 of the plurality of indoor units B, C, D, and the first branching portion 10 that is switchably connected to the connecting pipe 6 or the second connecting pipe 7. A second branch portion 11 connected and connected to the second connection pipe 7, and a first branch portion 10 branched from the second connection pipe 7.
And a flow rate control device that controls the flow rate of the refrigerant, which is provided in the middle of the pipeline that connects the pipe branching section 12 and the other of the indoor unit side heat exchangers 5 described above. A bypass pipe 14 in which the second branch portion 11 and the first connection pipe 6 are connected via a third flow control device 15, a third flow control device 15 and the first connection pipe 6 Between the bypass pipe 14 and the second indoor unit B, C, D side
And a heat exchange section for exchanging heat between the second connection pipes 7b, 7c, 7d and the pipes from the second connection pipes 7b, 7c, 7d to the pipe branch portion 12, and the first and second It is provided between the connection pipes 6 and 7, and by switching the direction of the flowing refrigerant, the low pressure of the first connection pipe 6 interposed between the heat source unit A and the indoor units B, C and D is always maintained during operation. An air conditioner characterized by being provided with a connection pipe switching device 40 for increasing the pressure of the second connection pipe 7 so that the cooling and heating can be simultaneously performed. 2. The first flow control device 9 is connected to the other of the indoor heat exchangers 5 of the indoor units B, C, D in close proximity to each other, and the second flow control device 13 is connected to the pipe branching portion 12. It is provided in the second connection pipe 7 between the second branch parts 11 and serves as a heat exchange part, and the bypass pipe 14
And a first heat exchanging part 19 for exchanging heat between the pipe branching part 12 and a pipe connecting the second flow rate control device 13 to each other. apparatus. 3. A bypass pipe 14 between the third flow control device 15 and the first connection pipe 6, each indoor unit B, C, D, and a second branch part 11 as a heat exchange part. The second and third heat exchange parts 16a, 16b, 16c, 16d for respectively exchanging heat with the confluence part of the indoor side connection pipes to be connected and the indoor side connection pipes are provided. The air conditioner according to item 1 or 2.