JPH0752045B2 - Air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-room heat pump type air conditioner in which a plurality of indoor units are connected to one heat source device, and in particular each indoor unit. The present invention relates to an air conditioner capable of selectively performing heating / cooling for each, or simultaneously performing cooling in one indoor unit and heating in the other indoor unit.

[Conventional technology]

Conventionally, a heat pump type air conditioner in which a plurality of indoor units are connected to one heat source device by two pipes of a gas pipe and a liquid pipe and a cooling and heating operation is common, and all the indoor units are heated. , Or all are formed so as to perform cooling.

[Problems to be Solved by the Invention]

Since the conventional multi-room heat pump type air conditioner is configured as described above, all indoor units operate only for heating or cooling, so heating is performed in a place where cooling is required, or vice versa. There was a problem that cooling was done in a place where heating was required, especially when installed in a large building, air conditioning in the interior part and perimeter part, or the general office room, and the office room such as the computer room This is a particular problem because the loads on the are significantly different.

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 or heating is selectively performed for each indoor unit, or one When it is installed in a large building, it can be used as OA for the interior section and perimeter section, or the general office room and computer room, etc. 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 Problems]

In the air conditioner according to the present invention, 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 are provided. , Connected via a second connection pipe, 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 plurality of indoor heat exchangers and connected to the second connection pipe, and provided in the middle of the second connection pipe And a gas-liquid separation device for separating the gas refrigerant and the liquid refrigerant, and a flow rate control device for controlling the refrigerant flow amount, which is provided in the middle of a pipeline connecting the gas-liquid separation device and the other of the indoor heat exchangers. And is provided between the first and second connecting pipes and cuts the direction of the flowing refrigerant. As a result, at the time of operation, the first connection pipe interposed between the heat source unit and the indoor unit is kept at a low pressure and the second connection pipe is kept at a high pressure at all times, and the second branch is provided. A fourth flow rate control device that communicates the above-mentioned part and the above-mentioned first connection pipe is provided to enable simultaneous cooling and heating operation.

Further, the first connecting pipe has a larger diameter than the second connecting pipe.

[Action]

In the present invention, in the case of mainly cooling in the heating / cooling simultaneous operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor exchanges an arbitrary amount of heat in the heat-source-side heat exchanger to become a gas-liquid two-phase high-temperature and high-pressure state. It flows into the gas-liquid separation device through the connection pipe. The inflowing refrigerant is separated into a gas refrigerant and a liquid refrigerant,
Only the gas refrigerant is supplied to the indoor unit to be heated via the first branch portion, condensed and liquefied, and flows into the second branch portion. On the other hand, the separated liquid refrigerant flows into the second branch portion, merges with the liquid refrigerant sent from the heating indoor unit, and is supplied to the indoor unit that is going to cool. In this way, the gas-liquid separation device accurately separates the gas refrigerant and the liquid refrigerant, and the flow rate control device appropriately supplies the refrigerant to the indoor unit that requires cooling or heating. You can drive.

Further, the first connecting pipe is always used on the low pressure side due to the function of the connecting pipe switching device, but since the first connecting pipe has a larger diameter than the second connecting pipe, the flow of the flowing refrigerant is The resistance can be suppressed to a small value, the evaporation pressure of the indoor unit to be cooled does not increase, and the cooling capacity does not become insufficient. Therefore, in the case of the cooling mainly in the cooling / heating simultaneous operation, in the case of the heating mainly, only in the cooling operation, the evaporating pressure of the indoor unit to be cooled does not rise, and the cooling capacity is not insufficient.

Further, in the case of heating mainly in the simultaneous heating and cooling operation, the high temperature gas refrigerant supplied to the indoor unit to be heated exchanges heat with the indoor air in the indoor heat exchanger to be condensed and liquefied to heat the room. The condensed and liquefied refrigerant flows into the second branch portion,
A part of it is supplied to the indoor unit to be cooled, and is evaporated and vaporized in the indoor heat exchanger to cool the room. The evaporated vaporized refrigerant flows into the first connecting pipe via the first branch portion. On the other hand, the remaining refrigerant in the second branch portion flows into the first connection pipe via the fourth flow rate control device, merges with the refrigerant sent from the indoor unit to be cooled, and connects to the connection pipe switching device. Through the heat source unit side heat exchanger. The refrigerant that has undergone heat exchange in this heat source unit side heat exchanger and has been evaporated and vaporized is sucked into the compressor. As described above, in the heating-based operation refrigeration cycle, since the first connection pipe forming the low pressure side is thick, the flow loss of the refrigerant flowing through the first connection pipe can be suppressed to be small, and the heat source The pressure of the machine side heat exchanger does not decrease, and the capacity does not decrease. Further, the evaporation pressure of the indoor unit does not rise and the cooling capacity does not become insufficient.

In addition, the connection pipe switching device always keeps the first connection pipe at a low pressure and the second connection pipe at a high pressure in any of the operation modes of the cooling only operation, the heating only operation, the cooling main operation, and the heating main operation. Even when the operation mode is changed between the cooling only operation, the cooling main operation and the heating only operation, and the heating main operation, the pressure fluctuation is suppressed and good transient characteristics are obtained.

Furthermore, since the pressure fluctuations are suppressed by the connection pipe switching device, the gas-liquid separation in the gas-liquid separation device is always properly separated between the gaseous refrigerant and the liquid refrigerant. The characteristics are obtained.

[Examples] Examples of the present invention will be described below.

FIG. 1 is an overall configuration diagram centering on the refrigerant system of the air conditioner of the first embodiment of the present invention. Also, FIGS. 2 to 4
The figure shows the operation state during the heating and cooling operation in one embodiment of FIG. 1, FIG. 2 shows the operation state diagram of only cooling or heating, and FIGS. 3 and 4 show the operation of the cooling and heating simultaneous operation. FIG. 3 is an operation state diagram showing a heating main body (when the heating operation capacity is larger than the cooling operation capacity) and FIG. 4 is a cooling main body (when the cooling operation capacity is larger than the heating operation capacity). . FIG. 5 is an overall configuration diagram centering on the refrigerant system of the air conditioner of another embodiment of the present invention.

In addition, in this embodiment, a case where three indoor units are connected to one heat source unit will be described, but the same applies to a case where 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 valve that switches the refrigerant flow direction of the heat source unit, (3) is a heat source unit side heat exchanger, (4) is an accumulator, and the above devices (1) to (3) And a heat source unit (A). (5) is three indoor heat exchangers, (6) is a thick first connecting pipe connecting the four-way 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) of the heat source unit (A) and the relay unit (E) The second connecting pipes (7b), (7c) and (7d), which are thinner than the connecting pipe (6) of the above, are the indoor heat exchanger (5) of the indoor units (B), (C) and (D), respectively. A second connection pipe on the indoor unit side that connects the repeater (E) and corresponds to the second connection pipe (7), (8) is the first connection pipe (6b), (6c) on the indoor unit side, (6d), a three-way switching valve that is switchably connected to the first connection pipe (6) or the second connection pipe (7) side, and (9) is close to the indoor heat exchanger (5). The first flow rate control device is controlled by the superheat amount on the outlet side of the indoor heat exchanger (5) when connected and cooling, and by the subcool amount when heating, and the second connection pipe (7b) on the indoor unit side. , (7c), Connected to (7d). (10) is the first connecting pipe (6b), (6
c), (6d) and the first branch part (11) comprising the three-way switching valve (8) switchably connected to the first connection pipe (6) or the second connection pipe (7), The second on the indoor unit side
Of the second connecting pipe (7) and the second branch portion (12) consisting of the connecting pipes (7b), (7c), (7d) and the second connecting pipe (7) are provided in the middle of the second connecting pipe (7). In the liquid separation device, 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). (1
3) is a second flow rate control device (14) which is connected between the gas-liquid separation device (12) and the second branch part (11) and which can be opened and closed.
Is a bypass pipe connecting the second branch portion (11) and the first connection pipe (6), (15) a third flow rate control device provided in the middle of the bypass pipe (14), (16b) , (16c),
(16d) is the third flow control device (1
5) is provided downstream of the third branch pipe (11) for performing heat exchange with the second connection pipes (7b), (7c), (7d) on the indoor unit side, respectively. The heat exchange part (16a) is provided downstream of the third flow rate control device (15) in the bypass pipe (14), and the second connection pipe (7b) on the side of each indoor unit in the second branch part (11). ), (7c), and (7d) the second heat exchange section for exchanging heat with the confluence section, (19) is located in the bypass pipe (14) downstream of the third flow rate control device and in the second section. A heat exchange part (16a) downstream of the first heat exchange part for exchanging heat between a gas-liquid separation device (12) and a pipe connecting the second flow rate control device (13), 17) is the second branch (1
An openable and closable fourth flow control device connected between 1) and the first connection pipe (6). (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 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 valve (2). (34) is a fifth check valve provided between the four-way valve (2) of the heat source unit (A) and the second connecting pipe (7), and the four-way 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 connecting pipe (6), and the first connecting pipe (6) To allow the refrigerant to flow only to the heat source unit 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, the high-temperature high-pressure refrigerant gas discharged from the compressor (1) passes through the four-way valve (2) as indicated by the solid arrow in FIG.
After the heat is exchanged in the heat source side heat exchanger (3) to be condensed and liquefied, the third check valve (32), the second connection pipe (7), the gas-liquid separation device (12), and the second Each of the indoor units (B) passes through the flow rate control device (13), further passes through the second branch section (11) and the second connection pipes (7b), (7c), (7d) on the indoor unit side,
It flows into (C) and (D). And each indoor unit (B),
The refrigerant flowing into (C) and (D) is decompressed to a low pressure by the first flow rate control device (9) which is controlled by the superheat amount at the outlet of each indoor heat exchanger (5), and indoor heat exchange is performed. In the vessel (5), heat is exchanged with the room air to evaporate and gasify, and the room is cooled. Then, the refrigerant in the gas state is the first connection pipes (6b), (6c), (6d) on the indoor unit side.
It passes through the three-way switching valve (8) and the first branch part (10), the first connecting pipe (6), the fourth check valve (33), the four-way valve (2) of the heat source device, and the accumulator (4). ), The circulation cycle is drawn into the compressor (1), and the cooling operation is performed.
At this time, the first port (8a) of the three-way exchange valve (8) is closed, the second
The mouth (8b) and the third mouth (8c) are open.

At this time, the refrigerant has a low pressure in the first connecting pipe (6),
Due to the high pressure in the connecting pipe (7), the fluid flows inevitably to the third check valve (32) and the fourth check valve (33). Also, during this cycle, a part of the refrigerant that has passed through the second flow rate control device (13) enters the bypass pipe (14) and is depressurized to a low pressure by the third flow rate control device (15) to cause the third heat exchange. Part (16b),
In (16c) and (16d), the second connection pipe (7
b), (7c), (7d), the second heat exchange section (16a)
Then, between the second branch part (11) and the confluence part of the second connection pipes (7b), (7c), (7d) on each indoor unit side, and in the first heat exchange part (19). The refrigerant that has exchanged heat with the refrigerant flowing into the second flow rate control device (13) and has evaporated evaporates into the first connecting pipe (6) and the fourth check valve (33), and then flows into the heat source unit 4. It is sucked into the compressor (1) through the one-way valve (2) and the accumulator (4).

On the other hand, the first, second and third heat exchange parts (19), (16a),
The indoor units (B), (C), (C) that are about to cool the refrigerant in the second branch section (11) that has been sufficiently heat-exchanged and cooled in (16b), (16c), and (16d) to provide subcooling. D)
Flow into.

Next, the case of only the heating operation will be described with reference to FIG. That is, the high-temperature high-pressure refrigerant gas discharged from the compressor (1) passes through the four-way valve (2), the fifth check valve (34), and the second connecting pipe as shown by the dotted arrow in the figure. (7), passing through the gas-liquid separator (12), the first branch (1
0), three-way switching valve (8), first connection pipe (6
b), (6c), (6d), in that 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), (7d) flow into the second branch part (11) and merge, and further pass through the fourth flow rate control device (17), where the first flow rate control device (9), Alternatively, the pressure is reduced to a low-pressure two-phase state by either the fourth flow rate control device (17). Then, the refrigerant decompressed to a low pressure flows through the first connecting pipe (6) into the sixth branch portion (35) of the heat source unit (A) and the heat source unit side heat exchanger (3) for heat exchange. And evaporates into a gas state, and constitutes a circulation cycle in which the heat source machine is sucked into the compressor (1) through the four-way valve (2) and the accumulator (4) to perform the heating operation. At this time, the second port (8b) of the three-way switching valve (8) is closed, and the first port (8a) and the third port (8c) are open.

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 fifth check valve (34) and the sixth check valve ( 35).

The case of mainly heating in the simultaneous heating and cooling operation will be described with reference to FIG.

That is, the high-temperature high-pressure refrigerant gas discharged from the compressor (1) passes through the four-way valve (2), the fifth check valve (34), and the second connecting pipe as shown by the dotted arrow in the figure. It is sent to the repeater (E) through (7), passes through the gas-liquid separator (12),
Then, the first branch portion (10), the three-way switching valve (8), the first connection pipes (6b), (6c) on the indoor unit side are passed in this order, and the indoor units (B), ( C), and heat-exchanges with indoor air in the indoor heat exchanger (5) to be condensed and liquefied to heat the room. Then, the condensed and liquefied refrigerant is controlled by the amount of subcool 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 third branch portion ( Inflow into 11). Then, a part of this refrigerant enters the indoor unit (D) that is going to be cooled through the second connection pipe (7d) on the indoor unit side, and is controlled by the superheat amount at the outlet of the indoor heat exchanger (5). First done
After entering the 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 through the three-way switching valve (8). Inflow of the first connecting pipe (6).

On the other hand, the other refrigerant will be cooled by passing through the fourth flow rate control device (17) which can be opened and closed controlled by the high pressure of the second connecting pipe (7) and the intermediate pressure value of the second branch portion (11). And the sixth check valve (35) of the heat source unit (A) and the heat exchanger (3) on the heat source unit side (3) through the thick first connection (6) with the refrigerant that has passed through the indoor unit (D) Into the gas state by heat exchange and evaporation. Then, the refrigerant is the four-way valve (2) of the heat source device,
A circulation cycle in which the air is taken into the compressor (1) through the accumulator (4) constitutes a heating-main operation. At this time, the pressure difference between the evaporating pressure of the indoor heat exchanger (5) of the indoor unit (D) to be cooled and the evaporating pressure of the heat source side heat exchanger (3) is in the thick first connection pipe (6). It becomes smaller for switching, and at this time, the second port (8b) of the three-way switching valve (8) connected to the indoor units (B) and (C) is closed, the first port (8a) and the third port ( 8c) is open circuit, the first of the indoor unit (D)
The mouth (8a) is closed, and the second mouth (8b) and the third mouth (8c) are open.

At this time, since the refrigerant has a low pressure in the first connecting pipe (6) and a high pressure in the second connecting pipe (7), the refrigerant inevitably has the fifth check valve (3).
4) and flows to the sixth check valve (35). Further, during this cycle, a part of the liquid refrigerant flows from the merging portion of the second connection pipes (7b), (7c), (7d) on the indoor unit side of the second branch portion (11) to the bypass pipe (14 ) 3rd flow controller (15)
The pressure is reduced to low pressure by the third heat exchange section (16b), (16
In c) and (16d), the second connecting pipe (7b) on each indoor unit side,
Between the (7c) and (7d), the second heat exchange section (16a) is connected to the second connection pipe (7) of the second branch section (11) on the indoor unit side.
The refrigerant that has exchanged heat with the merging portions of b), (7c) and (7d) and has evaporated enters the first connection pipe (6) and enters the sixth check valve () of the heat source unit (A). 35), heat source side heat exchanger (3)
Into the gas state by heat exchange and evaporation. Then, the refrigerant is sucked into the compressor (1) through the four-way valve (2) of the heat source device and the accumulator (4).

On the other hand, the second and third heat exchange parts (16a), (16b), (16
The refrigerant in the second branch portion (11), which has been heat-exchanged and cooled in c) 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. That is, the high-temperature high-pressure refrigerant gas discharged from the compressor (1) as indicated by the solid arrow in the figure is
An arbitrary amount of heat is exchanged in the heat source unit side heat exchanger (3) to form a two-phase high temperature and high pressure state, and the third check valve (32), the second connection pipe (7), and the relay unit (E) It is sent to the gas-liquid separator (12). And, here, the gaseous refrigerant is separated into the gaseous refrigerant and the liquid refrigerant, and the separated gaseous refrigerant is divided into the first branch portion (10), the three-way switching valve (8), and the first connection pipe (6d) on the indoor unit side. , In order to flow into the indoor unit (D) to be heated and exchange heat with the indoor air in the indoor heat exchanger (5) to condense and liquefy,
Heat the room. Further, it is controlled by the amount of subcool at the outlet of the indoor heat exchanger (5) and is slightly decompressed through the first flow rate control device (9) which is in a fully open state, and then the second branch portion (1
1), flow into. On the other hand, the remaining liquid refrigerant passes through the second flow control device (13) which can be opened and closed and is controlled by the high pressure of the second connecting pipe (7) and the intermediate pressure value of the second branching part (11). The refrigerant flows into the second branch (11) and joins the refrigerant having passed through the indoor unit (D) to be heated. The second branch portion (11) and the second connection pipes (7b) (7c) on the indoor unit side
In the order of, and flows into each of the indoor units (B) and (C). Then, the refrigerant flowing into each indoor unit (B), (C) is decompressed to a low pressure by the first flow rate control device (9) controlled by the superheat amount at the outlet of the indoor heat exchanger (5). It flows into the indoor heat exchanger (5), exchanges heat with the indoor air, evaporates and is gasified, and cools the room. Further, the refrigerant in the gas state is the first connection pipe (6b) on the indoor unit side,
(6c), three-way switching valve (8), first branch part (10), first connecting pipe (6), fourth check valve (33), four-way valve (2) of heat source unit A circulation cycle in which the air is sucked into the compressor (1) through the accumulator (4) to perform a cooling main operation. At this time, the first port (8a) of the three-way switching valve (8) connected to the indoor units (B) and (C) is closed, and the second port (8b) and the third port (8c) are open. The second opening (8b) of the indoor unit (D) is closed, and the first opening (8a) and the third opening (8c) are open.

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 ( 33). Further, during this cycle, a part of the liquid refrigerant flows from the confluence of the second connection pipes (7b), (7c) and (7d) on the indoor unit side of the second branch portion (11) to the bypass pipe (14). Enter the third flow controller (15)
Is reduced to a low pressure by the third heat exchange section (16b), (16
In c) and (16d), the second connecting pipe (7b) on each indoor unit side,
Between the (7c) and (7d), the second heat exchange section (16a) is connected to the second connection pipe (7) of the second branch section (11) on the indoor unit side.
b), (7c), (7d) and the confluence section, and further heat exchange with the refrigerant flowing into the second flow rate control device (13) in the first heat exchange section (19). The evaporated refrigerant enters the first connecting pipe (6), and the fourth check valve (33) of the heat source unit (A),
It is sucked into the compressor (1) through the four-way valve (2) of the heat source machine and the accumulator (4). On the other hand, the above-mentioned second branch which has been sufficiently cooled by exchanging heat with the first, second and third heat exchange parts (19), (16a), (16b), (16c) and (16d) The refrigerant in the section (11) 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 pipe (6
b), (6c), (6d) and the first connecting pipe (6) or the second connecting pipe (7) are switchably connected, but as shown in FIG. Valves (30), (31)
Even if an on-off valve such as the above is provided and the switchable connection is performed as described above, the same operational effect is obtained.

〔The invention's effect〕

As described above, the 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 connection pipes, 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. And a second branch pipe that is connected to the other of the plurality of indoor heat exchangers and that is connected to the second connection pipe. A gas-liquid separation device for separating the liquid refrigerant and a liquid refrigerant, and a flow rate control device for controlling the refrigerant flow rate, which is provided in the middle of the pipeline connecting the gas-liquid separation device and the other of the indoor heat exchangers, and the heat source unit Is provided between the first and second connection pipes, and cuts the direction of the flowing refrigerant. As a result, at the time of operation, the first connection pipe interposed between the heat source unit and the indoor unit is kept at a low pressure and the second connection pipe is kept at a high pressure at all times, and the second branch is provided. Since the fourth flow rate control device that communicates the above section with the first connection pipe is provided, it is possible to selectively perform a plurality of indoor units and simultaneously perform the cooling operation and the heating operation. At the same time, in the case of mainly cooling in the heating and cooling simultaneous operation, the gas-liquid separator separates the two-phase high-temperature high-pressure refrigerant flowing from the second connecting pipe into a gaseous refrigerant and a liquid refrigerant, and only the separated gaseous refrigerant Can be appropriately separated into a heating machine and the remaining liquid refrigerant into a cooling machine, and highly efficient simultaneous cooling and heating operation can be performed.

In addition, the connection pipe switching device always keeps the first connection pipe at a low pressure and the second connection pipe at a high pressure in any of the operation modes of the cooling only operation, the heating only operation, the cooling main operation, and the heating main operation. Even when the operation mode is changed between the cooling only operation, the cooling main operation and the heating only operation, and the heating main operation, the pressure fluctuation is suppressed and good transient characteristics are obtained.

Further, since the pressure fluctuation is suppressed by the connecting pipe switching device, the gas-liquid separation in the gas-liquid separation device is always adequately separated between the gaseous refrigerant and the liquid refrigerant, so that even during the simultaneous cooling and heating operation, it is preferable. Transient characteristics can be obtained.

Further, since the first connecting pipe is configured to have a large diameter by the second connecting pipe and the thicker connecting pipe can be always used for the low pressure side, in the case of the cooling mainly in the cooling / heating simultaneous operation, the heating main In this case, and when all the indoor units perform the cooling operation, the evaporation pressure of the indoor heat exchanger does not increase, and the cooling capacity does not become insufficient.

In the case of mainly heating, the evaporation pressure of the heat source side heat exchanger does not decrease, and the capacity does not decrease.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram centering on a refrigerant system of an air conditioner of a first embodiment of the present invention. FIG. 2 is a diagram showing the operation operation state of only the cooling or heating of the embodiment shown in FIG. 1, and FIG. 3 is the heating main body of the embodiment shown in FIG. 1 (the heating operation capacity is larger than the cooling operation capacity. Case) operation status diagram,
FIG. 4 is an operation state diagram showing the cooling main body (when the cooling operation capacity is larger than the heating operation capacity) of the embodiment shown in FIG. 1, and FIG. 5 is an air conditioner of another embodiment of the present invention. 2 is an overall configuration diagram centering on the refrigerant system of FIG. In the figure, A: heat source unit and B, C, and D indoor units have the same configuration. E: Repeater, 1; Compressor, 2; Switching valve, 3; Heat source side heat exchanger, 4; Accumulator, 5; Indoor side heat exchanger, 6;
First connection pipe, 6b, 6c, 6d; First connection pipe on the indoor unit side, 7; Second connection pipe, 7b, 7c, 7d; Second connection pipe on the indoor unit side, 8; Three-way switching Valve, 9; first flow controller, 10; first branch, 11; second branch, 12; gas-liquid separator, 13;
2nd flow control device, 14; bypass piping, 15; 3rd flow control device, 16; heat exchanger, 16a; 2nd heat exchange part, 16b, 16
c, 16d; third heat exchange section, 17; fourth flow rate control device, 18;
, 19; first heat exchange part, 30, 31; open / close valve such as solenoid valve, 32; third check valve, 33; fourth check valve, 34; fifth check valve, 35; A sixth check valve, 40; a connection pipe switching device. In the drawings, the same reference numerals and symbols indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A first and second connection of a 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. A first branching unit connected via a 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 second branch part connected to the other of the plurality of indoor heat exchangers and connected to the second connection pipe; and the second branch part.
A gas-liquid separation device that is provided in the middle of the connection pipe for separating the gas refrigerant and the liquid refrigerant, and a pipe line that connects the gas-liquid separation device and the other of the indoor heat exchangers, and the refrigerant flow rate. Is provided between the first and second connection pipes for controlling the flow rate, and switches the direction of the flowing refrigerant, so that the first source is always present between the heat source unit and the indoor unit during operation. A connection pipe switching device installed in the heat source unit for making the connection pipe of low pressure and the second connection pipe of high pressure communicate with the second branch portion and the first connection pipe.
The air conditioner, which is configured to be capable of simultaneous cooling and heating operation. 2. The air conditioner according to claim 1, wherein the first connecting pipe has a diameter larger than that of the second connecting pipe.