JPH07104074B2 - 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 in which cooling can be selectively performed, and cooling can be performed in one indoor unit and heating can be performed 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 with two pipes of a gas pipe and a liquid pipe to perform heating / cooling operation is general, and all the indoor units are heated. , Or all are configured to provide 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 cooling or heating, so heating is performed where cooling is required, and conversely heating is performed. There was a problem that the air conditioning was done where it was needed. Especially when installed in a large building,
This is a particular problem because the air-conditioning load is significantly different between the interior part and the perimeter part, or the general office, and the office room such as a computer room.

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 perform cooling and the other indoor unit can perform heating at the same time, the interior section and perimeter section, or the general office room and computerized room such as OA Therefore, it is an object of the present invention to obtain a multi-room heat pump type air conditioner capable of coping with each even if the load of the air conditioning is significantly different.

[Means for Solving the Problems]

An air conditioner according to claim 1 of the present invention is a compressor,
One heat source device including a switching valve and a heat source device side heat exchanger,
An indoor heat exchanger of the plurality of indoor units, wherein the indoor heat exchanger and the plurality of indoor units including the first flow rate control device are connected via the first and second connection pipes. A first branch portion provided with a valve device for switchably connecting one of the two to the first connection pipe or the second connection pipe via the third branch portion, and the chambers of the plurality of indoor units A second branch portion connected to the other of the inner heat exchangers via the first flow rate control device and connected to the second connection pipe, and the third branch portion of the second connection pipe. A second flow rate control device provided between the branching part and the second branching part, a fourth flow rate controlling device for communicating the second branching part with the first connecting pipe, and the first Is provided between the second connecting pipe and the second connecting pipe, and switches the flow of the refrigerant so that the heat source unit is always operated during operation. Between the connection pipe switching device that makes the first connection pipe interposed between the indoor units low and the second connection pipe high, and between the first branch portion and the second flow control device. Of the first pressure detecting means, the second pressure detecting means provided between the second flow rate control device and the fourth flow rate control device, and the first and second pressure detecting means. The fourth pressure is set so that the detected pressure difference is within a predetermined range.
And a flow rate control device control means for controlling the flow rate control device of (1), which is configured to be capable of simultaneous cooling and heating operations.

An air conditioner according to claim 2 of the present invention comprises
In the description, the first connecting pipe has a larger diameter than the second connecting pipe.

[Action]

In the present invention, in the case of heating mainly in the simultaneous heating and cooling operation, the high-pressure gas refrigerant is introduced from the heat source unit side switching valve, the second connecting pipe, and the first branch portion to each indoor unit to be heated to perform heating. After that, the refrigerant partially flows into the indoor unit that is about to be cooled from the second branch portion to perform cooling, and then flows into the first connection pipe from the first branch portion. on the other hand,
The remaining refrigerant passes through the fourth flow rate control device, merges with the refrigerant that has passed through the cooling indoor unit, flows into the first connecting pipe, and returns to the heat source unit side switching valve.

Further, in the case of mainly cooling, the high-pressure gas is heat-exchanged in an arbitrary amount by the heat source device to form a two-phase state, and the separated gaseous refrigerant is fed from the heat source device side switching valve and the second connecting pipe to the first branch portion. It is introduced into the indoor unit to be heated via the heating unit and heated to flow into the second branch portion. On the other hand, the remaining separated liquid refrigerant passes through the second flow rate control device and merges with the refrigerant that has passed through the indoor unit to be heated at the second branch portion and flows into each indoor unit to be cooled. After that, the air is cooled, and after that, it is guided from the first branch portion through the first connecting pipe to the heat source device side switching valve and returned to the compressor again.

Further, in the case of only the heating operation, the refrigerant is introduced into each indoor unit from the heat source unit side switching valve through the second connecting pipe and the first branching unit, and is heated to control the fourth flow rate from the second branching unit. Return to the heat source machine side switching valve through the device and the first connecting pipe. Further, the fourth flow rate control device is controlled so that the pressure difference detected by the first and second pressure detecting means falls within a predetermined range. Then, in the case of only the cooling operation, the refrigerant is introduced into each indoor unit from the heat source unit side switching valve through the second connecting pipe and the second branch portion, is cooled, and is cooled to the first connecting pipe from the first branch portion. Return to the heat source machine side switching valve.

〔Example〕

 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 machine, (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 the heat source unit side heat exchanger, (4) is an accumulator, and the above devices (1)-(3) And a heat source unit (A). (5) is three indoor units (B),
Indoor heat exchangers provided in (C) and (D), (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), (6c), and (6d) connect the indoor heat exchanger (5) and the relay (E) of the indoor units (B), (C), and (D), respectively, and connect the first connection pipe ( 6)
Corresponding to the first connection pipe on the indoor unit side, (7) is thinner than the first connection pipe connecting the heat source unit side heat exchanger (3) of the heat source unit (A) and the relay unit (E). One of the two connection pipes is connected to the heat source unit side heat exchanger (3), and the other end is connected to the second connection pipe (7
It is connected to the confluence of b), (7c), and (7d). (7
b), (7c) and (7d) are indoor units (B) and
Indoor heat exchanger (5) and repeater (E) of (C) and (D)
The second connection pipe on the indoor unit side that is connected via the second connection pipe (7), and (8) is the first connection pipe (6b), (6c), (6d) on the indoor unit side. And a three-way switching valve switchably connected to the first connection pipe (6) or the second connection pipe (7) side, and (9) is connected close to the indoor heat exchanger (5) The first flow rate control device is controlled by the superheat amount during cooling on the outlet side of the inner heat exchanger (5) and the subcool amount during heating, and the second connecting pipe (7) on the indoor unit side.
b), (7c), (7d). (10) is switchably connected to the first connection pipes (6b), (6c), (6d) on the indoor unit side and the first connection pipe (6) or the second connection pipe (7). A first branch consisting of a three-way switching valve (8),
(11) is the second connection pipe (7b), (7c) on the indoor unit side,
A second branch consisting of (7d) and a second connecting pipe (7),
(12) is the third provided in the middle of the second connecting pipe (7)
In the gas-liquid separation device that constitutes the branch portion of, the gas layer portion is connected to the first port (8a) of the three-way switching valve (8), and the liquid layer portion is connected to the second branch portion (11). ing. (13) is a second flow control device (electrical expansion valve in this case) that is connected between the gas-liquid separation device (12) and the second branch portion (11) and is openable and closable, and (14) is the first A bypass pipe connecting the second branch portion (11) and the first connection pipe (6), and (15) is a third flow rate control device (here, an electrical expansion device) provided in the middle of the bypass pipe (14). The valves) and (16a) are provided downstream of the third flow rate control device (15) provided in the middle of the bypass pipe (14), and the second branch portion (11) is provided with the second indoor unit side. A second heat exchange section that performs heat exchange with the joining sections of the connection pipes (7b), (7c), (7d), (16b), (16c),
(16d) are provided downstream of the third flow rate control device (15) provided in the middle of the bypass pipe (14), respectively.
The third heat exchange section (19) for exchanging heat with the second connection pipes (7b), (7c), (7d) on the indoor unit side in the branch section (11) of the A gas-liquid separation device (12) and a second flow rate control device (13) provided in the pipe (14) downstream of the third flow rate control device (15) and downstream of the second heat exchange section (16a). A first heat exchanging part for exchanging heat with a pipe for connecting the pipe, (17) connected between the second branch part (11) and the first connecting pipe (6) is openable and closable. A fourth flow control device (here, an electric expansion valve). (32)
Is a third check valve provided between the heat source unit side heat exchanger (3) and the second connection pipe (7). From the heat source unit side heat exchanger (3) to The refrigerant is allowed to flow only to the second connecting pipe (7). (33) is the heat source unit (A)
Is a fourth check valve provided between the four-way valve (2) and the first connecting pipe (6), the first connecting pipe (6) to the four-way valve (2). Allows refrigerant flow only to. (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 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, fourth, fifth and sixth check valves (3
The switching valve (40) is composed of 2), (33), (34), and (35). (25) is a first pressure detecting means provided between the first branch portion (10) and the second flow rate control device (13), (2)
6) is a second pressure detecting means provided between the second flow control device (13) and the fourth flow control device (17).

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) is passed through the flow rate control device (13), further 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) controlled by the superheat amount at the outlet of each indoor heat exchanger (5), and the 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. The refrigerant in the gas state is used for the first connection pipes (6b), (6c), (6) on the indoor unit side.
d), three-way switching valve (8), first branch part (10), first connecting pipe (6), fourth check valve (33), four-way valve (2) of heat source device, accumulator ( After 4), the circulation cycle is drawn into the compressor (1) to perform the cooling operation.
At this time, the first port (8a) of the three-way switching valve (8) is closed and the second port (8a) is closed.
The mouth (8b) and the third mouth (8c) are open. This time,
Since the first connecting pipe (6) has a low pressure and the second connecting pipe (7) has a high pressure, they necessarily flow to the third check valve (32) and the fourth check valve (33).

In addition, 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 generate the third heat. In the exchange parts (16b), (16c), (16d), between the second connection pipes (7b), (7c), (7d) on the indoor unit side of the second branch part (11), The second branch part (11) in the second heat exchange part (16a)
Second connection pipes (7b), (7c), (7d) on each indoor unit side of
And the confluence part of the first heat exchange part (19) with the refrigerant flowing into the second flow rate control device (13), and the evaporated refrigerant is the first connection pipe. (6), enters the fourth check valve (33), and 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 first
A few heat exchange parts (19), (16a), (16b), (16
The refrigerant in the second branch portion (11), which is cooled by heat exchange in c) and (16d) and is sufficiently subcooled, flows into the indoor units (B), (C), and (D) that are about to be cooled. . At this time, the connection pipes (7b), (7c), (7d) are filled with the liquid refrigerant.

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 first 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 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. The refrigerant in the liquid state is controlled by the amount of subcool at the outlet of each indoor heat exchanger (5) and is in a substantially fully opened state in the first flow rate control device (9).
Through the second connecting pipes (7b), (7c) on the indoor unit side,
From (7d), they flow into the second branch section (11) and merge, and further pass through the fourth flow rate control device (17). Here, the refrigerant is kept in a liquid state even after decompression by the first flow rate control device (9), and the refrigerant is kept in the gas-liquid two-phase state only after decompression by the fourth flow rate control device (17). Control the flow rate control device (17). As a result, the connection pipes (7b), (7c), (7d) are filled with the liquid refrigerant. Connection pipe (7b), even in the case of only cooling operation
Although (7c) and (7d) are filled with the liquid refrigerant, the fourth flow rate control device is arranged so that the connecting pipes (7b), (7c), and (7d) are in a two-phase state only during heating operation. If (17) is controlled, the connection pipes (7b), (7c), and
The amount of refrigerant in the connecting pipes (7b), (7c), (7d) decreases by the amount of the refrigerant specific gravity smaller than the amount of mass refrigerant retained in (7d), and the liquid retained in the accumulator (4) as excess refrigerant. The amount of refrigerant increases. However, in this embodiment, since the refrigerant in the connection pipes (7b), (7c), (7d) is in a liquid state, the mass refrigerant amount held in the connection pipes (7b), (7c), (7d) is the cooling amount. There is not much difference from the case of only driving. For this reason,
There is no excess cooling, the capacity of the accumulator (4) can be reduced, the liquid back to the compressor (1) is small, and the reliability of the compressor (1) can be improved. Then, the refrigerant decompressed to a low pressure flows through the first connecting pipe (6) into the sixth check valve (35) of the heat source unit (A) and the heat source unit side heat exchanger (3) to exchange heat. The evaporated refrigerant in a gas state constitutes a circulation cycle in which the refrigerant is sucked into the compressor (1) through the four-way valve (2) and the accumulator (4) of the heat source unit to perform the heating operation. At this time, the three-way switching valve (8) is
The mouth (8b) is closed, and the first mouth (8a) and the third mouth (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), as indicated by the dotted arrow in the figure, passes through the fifth check valve (3).
4), sent to the repeater (E) through the second connecting pipe (7), passes through the gas-liquid separation device (12), and the first branch portion (10), three-way switching valve (8), indoor unit The first connection pipes (6b) and (6c) on the side are passed in this order to the indoor units (B) and (C) that are going to be heated, and the indoor heat exchanger (5) exchanges heat with the indoor air. Then it is condensed and liquefied to heat the room. Then, the condensed and liquefied refrigerant is used in each indoor heat exchanger (B).
(C) It is controlled by the amount of subcool at the outlet, is slightly decompressed through the first flow rate control device (9) in a substantially fully opened state, and then the second
Flows into the branch road (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 (D). After entering the first flow rate control device (9) and being decompressed, the indoor heat exchanger (5)
It enters and exchanges heat to be vaporized into a gas state to cool the inside of the room and flow into the first connecting pipe (6) through the three-way switching valve (8).

On the other hand, the other refrigerant will be cooled by passing through the fourth flow rate control device (17) controlled by the pressure detected by the first pressure detecting means (25) and the pressure detected by the second pressure detecting means (26). The sixth check valve (3) of the heat source unit (A) merges with the refrigerant that has passed through the indoor unit (D) and passes through the thick first connection pipe (6).
5), It flows into the heat source side heat exchanger (3), exchanges heat and evaporates to become a gas state. Then, the refrigerant constitutes a circulation cycle in which it is sucked into the compressor (1) through the four-way valve (2) of the heat source device and the accumulator (4), and performs heating-main operation. At this time, the evaporation pressure of the indoor heat exchanger (5) of the indoor unit (D) to be cooled and the pressure difference of the heat source machine side heat exchanger (3) are small in order to switch to the thick first connecting pipe (6). Become. 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) is closed.
The third port (8c) is open, the first port (8a) of the indoor unit (D) is closed, and the second port (8b) 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).

In addition, during this cycle, a part of the liquid refrigerant flows into 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 the second heat is removed at the third heat exchange parts (16b), (16c), and (16d). The second branch part (11) in the second heat exchange part (16a) between the branch part (11) and the second connection pipes (7b), (7c), (7d) on the indoor unit side. The refrigerant that has exchanged heat with the confluence of the second connection pipes (7b), (7c), (7d) on each indoor unit side of the first connection pipe (6), It enters the check valve (35) and is sucked into the compressor (1) via 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), (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) which 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, as indicated by the solid arrow in the figure, the refrigerant gas discharged from the compressor (1) exchanges an arbitrary amount with the heat source side heat exchanger (3) to be in a two-phase high temperature and high pressure state. It is sent to the gas-liquid separation device (12) of the relay machine (E) via the check valve (32) of No. 3 and the second connecting pipe (7). Then, here, the gaseous refrigerant is separated into a gaseous refrigerant and a liquid refrigerant, and the separated gaseous refrigerant is divided into a first branch portion (10), a three-way switching valve (8), and a first connection pipe (6d) on the indoor unit side. In order to heat the room, it flows into the indoor unit (D) to be heated, heat-exchanges with the indoor air in the indoor heat exchanger (5) to be condensed and liquefied, and heats the room. Further, it is controlled by the amount of subcool at the outlet of the indoor side heat exchanger (5), is slightly decompressed through the first fully open flow rate control device (9), and then flows into the second branch portion (11). on the other hand,
The remaining liquid refrigerant passes through the second flow rate control device (13) controlled by the pressure detected by the first pressure detecting means (25) and the pressure detected by the second pressure detecting means (26), and then the second branch. It flows into the section (11) 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). Then, the refrigerant flowing into each indoor unit (B), (C) is low in pressure by the first flow rate control device (9) controlled by the superheat amount at the outlets of the indoor heat exchangers (B), (C). It is decompressed and heat-exchanges with room air to evaporate and gasify to cool the room. Further, the refrigerant in the gas state is used for the first connection pipes (6b) and (6c) on the indoor unit side, the three-way switching valve (8), the first
To the compressor (1) via the first connecting pipe (6), the fourth check valve (33), the four-way valve (2) of the heat source device, and the accumulator (4) through the branch part (10) of It constitutes a circulation cycle that is inhaled and performs 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 opened. The second port (8b) of the indoor unit (D) is closed, and the first port (8a) and the third port (8c) are open. At this time, the refrigerant is inevitably the third check valve (32) and the fourth check valve (32) because the first connection pipe (6) has a low pressure and the second connection pipe (7) has a high pressure.
To the check valve (33).

In addition, during this cycle, a part of the liquid refrigerant flows into 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 the second heat is removed at the third heat exchange parts (16b), (16c), and (16d). The second branch part (11) in the second heat exchange part (16a) between the branch part (11) and the second connection pipes (7b), (7c), (7d) on the indoor unit side. The second flow rate control device (13) between the second connection pipes (7b), (7c) and (7d) of each indoor unit side and the first heat exchange part (19). The refrigerant that has undergone heat exchange with the refrigerant flowing into the refrigerant flows into the first connecting pipe (6) and the fourth check valve (33), and enters into the four-way valve (2) of the heat source device and the accumulator (4). ) And is sucked into the compressor (1). On the other hand, the first
A few heat exchange parts (19), (16a), (16b), (16
The refrigerant in the second branch portion (11), which is cooled by heat exchange in c) and (16d) and is sufficiently subcooled, flows into the indoor units (B) and (C) that are about to be cooled.

Next, the control of the fourth flow rate control device (17) in the case of only heating operation or mainly heating will be described. FIG. 6 shows the control mechanism of the fourth flow control device (17), and FIG. 7 is a flow chart showing its operation. Further, (28) is a flow control device control means for controlling the valve opening degree of the fourth flow control device (17) according to the pressure difference detected by the first and second pressure detection means (25), (26). Is. An indoor unit (B) that tries to heat when the pressure difference ΔP ₃₂ detected by the first and second pressure detecting means (25) and (26) becomes less than or equal to a lower limit value ΔP ₁ ,
Even if the first flow control device (9) of (C) is fully opened, the pressure difference before and after the first flow control device (9) is small, and the flow rate of the refrigerant required for heating is not supplied. Further, when the pressure difference ΔP ₃₂ exceeds a certain upper limit value ΔP ₂ , even if the liquid refrigerant after passing through the indoor heat exchanger is sufficiently subcooled, the first
After the pressure is reduced by the flow rate control device (9), the pressure drop width is large and the supercooled state cannot be maintained, and the connecting pipes (7b), (7c), (7d) are connected to the gas-liquid two It will be in phase. Therefore, the pressure difference ΔP ₃₂ is set to be between the first target pressure difference ΔP _Md which is larger than ΔP _{1 and} is set in advance and the second target pressure difference ΔP _Mu which is smaller than ΔP _{2 and} is set to the fourth target pressure difference ΔP _Mu .
By controlling the flow control device (17) of the above, sufficient refrigerant can be supplied to the indoor units (B) and (C) to be heated, and the connection pipes (7b), (7c) and (7d). Can be filled with a liquid monolayer.

In step (50) of FIG. 7, the pressure difference ΔP ₃₂ is calculated, and in step (51), ΔP ₃₂ is compared with ΔP _Md, and ΔP ₃₂ <ΔP _Md
If so, the opening degree of the fourth flow rate control device (17) is increased in step (54) and the process returns to step (50). On the other hand, ΔP ₃₂ ≧ P
_{If Md} , proceed to step (55) and compare ΔP ₃₂ with ΔP _Mu . If ΔP ₃₂ > ΔP _Mu , the opening degree of the fourth flow control device (17) is decreased in step (57), and the process returns to step (50). If ΔP ₃₂ ≦ ΔP _Mu , the process returns to step (50). In this way, the pressure difference ΔP ₃₂ can be kept within a certain range. 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 are connected,
Although it is switchably connected to the first connecting pipe (6) or the second connecting pipe (7), as shown in FIG. 5, two solenoid valves (30), (31), etc. Even if the switch 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 according to claim 1 of the present invention comprises a compressor, a switching valve, a heat source side heat exchanger, and the like.
A plurality of indoor units in which a plurality of indoor heat exchangers and a plurality of indoor units including an indoor heat exchanger and a first flow control device are connected via first and second connection pipes. A first branch part provided with a valve device for switchably connecting one of the indoor heat exchangers to the second connection pipe via the first connection pipe or the third branch part; A second one connected to the other of the indoor heat exchangers of the indoor unit of the table via the first flow control device and connected to the second connection pipe.
Second branch portion, a second flow rate control device provided between the third branch portion and the second branch portion of the second connection pipe, the second branch portion and the first connection. A fourth flow rate control device that communicates with the pipe, and is provided between the first connection pipe and the second connection pipe, and switches the flow of the refrigerant so that the heat source unit and the indoor unit are always operated during operation. The connection pipe switching device that interposes the first connection pipe to a low pressure and the second connection pipe to a high pressure is provided between the first branch portion and the second flow control device. A first pressure detection means, a second pressure detection means provided between the second flow rate control device and the fourth flow rate control device, and a pressure difference detected by the first and second pressure detection means. And a flow rate control device control means for controlling the fourth flow rate control device so that the pressure is within a predetermined range. It is intended.

Therefore, simultaneous cooling and heating operation is possible, sufficient refrigerant can be supplied to the heating indoor unit, and the connection pipe between the first flow rate control device and the second branch portion is filled with the liquid refrigerant.
The amount of surplus refrigerant is reduced, liquid back to the compressor is reduced, and there is an effect of improving the reliability of the compressor.

According to a second aspect of the present invention, in the air conditioner according to the first aspect, the first connecting pipe has a larger diameter than the second connecting pipe.

Therefore, in addition to the above effects, during heating-main operation, the pressure difference between the evaporation pressure of the indoor heat exchanger of the cooling indoor unit and the evaporation pressure of the heat source side exchanger becomes small, and the evaporation pressure of the indoor heat exchanger decreases. Does not increase, the cooling capacity does not become insufficient, and the evaporation pressure of the heat source side heat exchanger does not decrease, so the suction pressure of the compressor does not decrease, and the compressor The effect is that the ability does not decrease.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram centering on the refrigerant system of the air conditioner of the 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. 6 and 7
The drawings are a block diagram and a flow chart of a flow control device control means system of the device of the present invention. In the figure, (A) is a heat source device, (B), (C), (D)
Is an indoor unit, (E) is a repeater, (1) is a compressor, (2) is a four-way valve of a heat source unit, (3) is a heat source side heat exchanger, (4) is an accumulator, and (5) is Indoor heat exchanger, (6) is the first connecting pipe, (6b), (6c), (6d) is the indoor first
Connection pipe, (7) is the second connection pipe, (7b), (7
c) and (7d) are second connection pipes on the indoor side, (8) is a three-way switching valve, (9) is a first flow rate control device, (10) is a first branch portion, and (11) is a first 2 branches, (12) a gas-liquid separator (third branch), (13) a second flow controller, (1
4) is bypass piping, (15) is the third flow controller, (1
9), (16a), (16b), (16c) and (16d) are heat exchange parts, (17) is a fourth flow rate control device, (25) and (26) are pressure detecting means, (32), (33), (34) and (35) are check valves, and (40) is a flow controller control means. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A heat source unit comprising a compressor, a switching valve, a heat source unit side heat exchanger and the like, and a plurality of indoor units comprising an indoor side heat exchanger and a first flow rate control device, In the one connected through the first and second connection pipes, one of the indoor heat exchangers of the plurality of indoor units is connected through the first connection pipe or the third branch portion to the second connection. A first branch portion having a valve device that is switchably connected to the pipe, and the other of the indoor heat exchangers of the plurality of indoor units via the first flow control device, and the first flow control device. A second branch portion connected to the second connection pipe; a second flow rate control device provided between the third branch portion and the second branch portion of the second connection pipe; A fourth flow rate control device that connects the second branch portion and the first connection pipe, and the first connection pipe and the second connection pipe. A heat source unit for switching the flow of the refrigerant so that the first connecting pipe interposed between the heat source unit and the indoor unit is set to a low pressure and the second connecting pipe is set to a high pressure at all times during operation. Connection pipe switching device provided on the side, first pressure detecting means provided between the first branch portion and the second flow rate control device, the second flow rate control device, and the fourth flow rate control device. The pressure difference between the second pressure detecting means provided between the flow rate control device and the first and second pressure detecting means is set to be not less than the first target pressure difference and not more than the second target pressure difference. An air conditioner comprising: a flow rate control device controlling means for controlling the fourth flow rate control device; 2. The air conditioner according to claim 1, wherein the first connecting pipe has a larger diameter than the second connecting pipe.