JPH0765826B2 - 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 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 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 be used for cooling and the other indoor unit can be used for heating at the same time, the Intel Office and perimeter sections, or the general office and computerized rooms such as OA rooms Therefore, it is an object of the present invention to obtain a multi-room heat pump 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. It is provided between the second flow rate control device provided between the branch portion and the second branch portion and the first connection pipe and the second connection pipe, and by switching the flow of the refrigerant, during operation, Always keep the first connecting pipe interposed between the heat source unit and the indoor unit at a low pressure and the second connecting pipe at A connection pipe switching device for applying pressure, a bypass pipe having one end connected to the second branch portion and the other end connected to the first connection pipe via the third flow rate control device, and the second branch portion. And a fourth flow rate control device for communicating the first connection pipe with each other, a confluence portion of indoor connection pipes connecting each indoor unit and the second branch portion, and an indoor connection pipe with the bypass pipe. A heat exchanging section for exchanging heat with the downstream section of the third flow rate control device; and a first pressure detecting means provided between the first branch section and the second flow rate control apparatus. A second pressure detecting means provided between the second flow control device and the fourth flow control device, and the first and second
And a flow rate control device control means for controlling at least one of the third and fourth flow rate control devices so that the pressure difference detected by the pressure detection means falls within a predetermined range, and the cooling and heating simultaneous operation is possible. It is characterized by that.

An air conditioner according to claim 2 of the present invention comprises
In the description, when the flow rates of the third and fourth flow rate control devices are increased during a predetermined operation, the flow rate control device control means includes:
The third flow rate control device is prioritized.

An air conditioner according to claim 2 of the present invention comprises
In the description, in the case of decreasing the flow rates of the third and fourth flow rate control devices during a predetermined operation, the flow rate control device control means is
The fourth flow rate control device is prioritized.

[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, a part of the refrigerant is circulated from the second branch section through a bypass pipe, heat is exchanged in the heat exchanging section, the refrigerant flowing into the second branch section and the indoor unit about to be cooled. Cool the inflowing refrigerant and provide sufficient subcooling. Further, the third and fourth pressure detecting means are arranged so that the pressure difference detected by the first and second pressure detecting means falls within a predetermined range.
When controlling the flow rate control device of No. 1 and increasing the flow rates of the third and fourth flow rate control devices, the third flow rate control device is given priority, and the flow rates of the third and fourth flow rate control devices are decreased. When making it do, the 4th flow control device is given priority.

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 that is going to be heated and flows into the second branch portion that performs heating. 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, a part of the refrigerant is circulated from the second branch section through a bypass pipe, heat is exchanged in the heat exchanging section, the refrigerant flowing into the second branch section and the indoor unit about to be cooled. Cool the inflowing refrigerant and provide sufficient subcooling.

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.

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 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 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). Second connection pipe,
(7b), (7c), (7d) are indoor units (B),
Indoor heat exchanger (5) and repeater (E) of (C) and (D)
To the second connecting pipe (7) through the first connecting pipe
Corresponding to the second connection pipe on the indoor unit side, (8) is the first connection pipe (6b), (6c), (6d) on the indoor unit side, and the first connection pipe (6) or A three-way switching valve that is switchably connected to the connection pipe (7) side of 2, and (9) is connected in close proximity to the indoor heat exchanger (5) during cooling of the outlet side of the indoor heat exchanger (5). Is a first flow rate control device that is controlled by the superheat amount 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) on the indoor unit side,
(6d) and a first branch portion comprising a three-way switching valve (8) switchably connected to the first connection pipe (6) or the second connection pipe (7), and (11) is an indoor unit side A second branch portion consisting of the second connecting pipes (7b), (7c), (7d) and the second connecting pipe (7), and (12) provided in the middle of the second connecting pipe (7). In the gas-liquid separation device that constitutes the third branched portion,
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). (13) is a gas-liquid separator (12) and a second branch (1
A second flow control device (here, an electric expansion valve) that can be opened and closed and is connected to the first branch part (1).
A bypass pipe connecting 1) to the first connection pipe (6), (15) a third flow control device (here, an electric expansion valve) provided in the middle of the bypass pipe (14), (16a )
Is provided downstream of the third flow rate control device (15) provided in the middle of the bypass pipe (14), and the second connection pipe (7b) on each indoor unit side in the second branch portion (11), (7c),
The second heat exchange parts, (16b), (16c), and (16d), which perform heat exchange with the merging part of (7d), respectively, are the third flow rate provided in the middle of the bypass pipe (14). A first unit provided downstream of the control unit (15) for performing heat exchange with the second connection pipes (7b), (7c), (7d) on the indoor side in the second branch section (11). 3 heat exchange part, (19)
A gas-liquid separation device (12) and a second flow rate control device (13) provided downstream of the third flow rate control device (15) in the bypass pipe (14) and downstream of the second heat exchange section (16a). A first heat exchanging part for exchanging heat with a pipe connecting with, and (17) openable and closable connected between the second branch part (11) and the first connecting pipe (6). A fourth flow control device (here, an electric expansion valve). (32) is the heat source unit side heat exchanger (3)
Is a third check valve provided between the heat source unit side heat exchanger (3) and the second connection pipe (7). Tolerate. (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 the first connecting pipe (6) To allow the refrigerant to flow only 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) ) From above the second
The refrigerant is allowed to flow only to the connecting pipe (7). (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) to the heat source Allow the refrigerant to flow only to the machine side heat exchanger (3). The third, fourth, fifth and sixth
Check valves (32), (33), (34), (35) for switching valve (4
0) constitutes. (25) is a first pressure detecting means provided between the first branch portion (10) and the second flow control device (13), and (26) is the second flow control device (13). And the fourth
The second pressure detecting means is provided between the second pressure detecting means and the flow rate controlling 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 be vaporized and gasified to cool the room. The refrigerant in the gas state is used as the first connection pipes (6b), (6c), (6
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. At this time,
Since the first connection closed (6) has a low pressure and the second connection pipe (7) has a high pressure, it necessarily flows 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)
To the second flow rate control device (13) between the second connection pipes (7b), (7c), and the confluence part of (7d) on each indoor side, and the first heat exchange part (19). The refrigerant that has exchanged heat with the inflowing refrigerant and evaporates enters the first connection pipe (6), the fourth check valve (33), and the four-way valve (2) of the heat source unit, 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), (C), and (D) that are about to be cooled. .

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 first flow control device (9) or the third and fourth flow control devices (1
Either one of 5) and (17) is used to reduce the pressure to a low pressure gas-liquid two-phase state. The refrigerant decompressed to a low pressure is
The refrigerant that has flowed into the sixth check valve (35) of the heat source unit (A) and the heat exchanger (3) on the heat source unit side through the connection pipe (6) to evaporate by heat exchange into a gas state, Four-way valve (2) of heat source machine,
A circulation cycle in which the air is taken into the compressor (1) through the accumulator (4) constitutes a heating operation. At this time,
The three-way switching valve (8) has the second port (8b) closed and the first port (8b) closed.
a) and the third mouth (8c) are open. At this time, the refrigerant is inevitably the fifth check valve (34) and the sixth check valve (34) because the first connection pipe (6) has a low pressure and the second connection pipe (7) has a high pressure.
To the 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 part (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 heat-exchanges to become an evaporative gas state, cools the room, and flows into the first connecting pipe (6) through the three-way switching valve (8).

On the other hand, the other flow rate control device controls the other refrigerants so that the pressure difference between the pressure detected by the first pressure detection means (25) and the pressure detected by the second pressure detection means (26) falls within a predetermined range. (1
The sixth check valve (35) of the heat source unit (A), which merges with the refrigerant passing through the indoor unit (D) to be cooled through 7) and passes through the thick first connecting pipe (6), Heat source machine side heat exchanger (3)
Into the gas state by heat exchange and evaporation. 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, in order to switch 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 heat exchanger (3) to the thick first connection pipe (6). Get smaller. At this time, the second of the three-way switching valve (8) connected to the indoor units (B) and (C)
The mouth (8b) is closed, the first mouth (8a) and the third mouth (8c) are open, and the first mouth (8a) of the indoor unit (D) is closed and 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) 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 this order, the air flows into the indoor unit (D) to be heated, heat-exchanges with the indoor air in the indoor heat exchanger (5) to be liquefied, and is heated indoors. 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) to be cooled. Next, control of the third and fourth flow rate control devices (15) and (17) in the case of simultaneous heating and cooling operation will be described. FIG. 6 shows the control mechanisms of the third and fourth flow rate control devices (15) and (17), and FIG. 7 is a flow chart showing the operation thereof. Further, (28) is the first and second pressure detecting means (25),
Flow control device control means for controlling the valve opening of the third and fourth flow control devices (15) and (17) according to the pressure difference detected in (26). The first flow rate control device (9) of the indoor units (B), (C) that are going to heat when the pressure difference ΔP32 detected by the first and second pressure detecting means (25), (26) becomes less than a certain value ΔP1. Since the pressure difference before and after (1) is small, even if the first flow rate control device (9) is fully opened, it is not possible to flow the refrigerant at a flow rate required to obtain a predetermined heating capacity. Further, when the pressure difference ΔP32 exceeds a certain value ΔP2, the pressure detected by the second pressure detecting means decreases, so that the saturation temperature of the refrigerant decreases and the temperature difference from the saturation temperature of the bypass side refrigerant in the heat exchange section. Is reduced, the heat exchange parts (16a), (16b), (16
In (c) and (16d), sufficient heat exchange is not performed (the pressure detected by the first pressure detection means and the bypass-side refrigerant pressure do not change), and the refrigerant is distributed to the indoor unit (D) that is about to be cooled. As a result, the refrigerant flowing into the indoor unit (D) is not sufficiently subcooled, and stable refrigerant supply cannot be achieved. Therefore, the pressure difference ΔP ₃₂ is set 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 which is set in advance. By controlling the fourth flow rate control devices (15) and (17), the pressure difference detected by the first and second pressure detection means is controlled within a predetermined range. The pressure difference between the first and second flow rate control devices can be controlled to supply the refrigerant required to obtain a predetermined heating capacity within the opening range of the first flow rate control device, and the heat exchange parts (16a), (16b), (16c) , (16
It is possible to secure a sufficient subcool in d). or,
In order to bring the pressure difference ΔP ₃₂ into a predetermined range, the valve opening degree of any of the third and fourth flow rate control devices (15) and (17) may be increased or decreased. (15) has a function of controlling the flow rate of the cooling side refrigerant of the heat exchange sections (16a), (16b), (16c), (16d), and when both increase, the third flow rate control device (15) ) Is preferentially increased, and when both are decreased, the fourth flow rate control device (17) is preferentially decreased so that the heat exchange sections (16a), (16b), (16)
It is possible to secure a sufficient flow rate of the cooling side refrigerant in c) and (16d).

FIG. 7 step (50) in calculates the pressure difference [Delta] P _32, the [Delta] P ₃₂ in step (51) compared to P _Md, if ΔP ₃₂ <P _Md, third flow rate control in step (52) It is determined whether or not the opening degree of the device (15) is the full opening value, and if it is not the full opening value, the opening degree of the third flow control device (15) is increased in step (53),
If it is a fully open value, the opening degree of the fourth flow control device (17) is increased in step (54), and the process returns to step (50). On the other hand, if ΔP ₃₂ ≧ P _Md , the process proceeds to step (55),
Compare ΔP ₃₂ with P _MU . If ΔP ₃₂ > P _MU, it is determined in step (56) whether or not the opening of the fourth flow rate control device (17) is the fully closed value, and if it is not the fully closed value, the fourth flow is performed in step (57). The opening degree of the flow rate control device (17) is decreased, and if it is a fully closed value, the opening degree of the third flow rate control device (15) is decreased in step (58), and the process returns to step (50). Also, ΔP ₃₂ ≤ P
_In case of _MU , return to step (50). In this way, the pressure difference ΔP ₃₂ can be maintained within a certain range while sufficiently securing the cooling-side refrigerant flow rate in the heat exchange parts (16a), (16b), (16c), (16d). In the above embodiment, the three-way switching valve (8)
And the first connection pipes (6b), (6c) on the indoor unit side,
(6d) and the first connecting pipe (6) or the second connecting pipe (7) are switchably connected, but as shown in FIG. 5, two solenoid 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 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.
Of 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, the first connection pipe and the second connection pipe It is installed in between, and by switching the flow of the refrigerant, during operation,
A connection pipe switching device that makes the first connection pipe interposed between the heat source unit and the indoor unit have a low pressure and the second connection pipe has a high pressure, and one end is connected to the second branch portion and the other end is Third
A bypass pipe connected to the first connection pipe via the flow control device, a fourth flow control device for communicating the second branch portion with the first connection pipe, each indoor unit, and Two
A heat exchange part for exchanging heat between the confluence part of the indoor connection pipes connecting the branch parts and the indoor connection pipe and the downstream part of the third flow rate control device of the bypass pipe; 1st pressure detection means provided between the 1st branch part and the said 2nd flow control device, and the 2nd pressure provided between the said 2nd flow control device and the said 4th flow control device. Detection means,
And a flow rate control device control means for controlling at least one of the third and fourth flow rate control devices so that the pressure difference detected by the first and second pressure detection means falls within a predetermined range. Is.

Therefore, simultaneous cooling and heating can be performed, and since the liquid refrigerant can be sufficiently supercooled before being distributed to the indoor unit, the distributability of the liquid refrigerant is improved and the liquid refrigerant is stabilized in the cooling indoor unit. It is possible to improve the amount of refrigerant supplied to the indoor heat exchanger, prevent the performance deterioration of the first to third heat exchangers, and solve the shortage of cooling capacity. There is an effect that sufficient refrigerant can be supplied also to the indoor unit.

According to a second aspect of the present invention, in the air conditioner according to the first aspect, when the flow rates of the third and fourth flow rate control devices are increased during a predetermined operation, the flow rate control device control means controls the third flow rate. The control device is prioritized, and the air conditioner according to claim 3 prioritizes the fourth flow control device when the flow rates of the third and fourth flow control devices are reduced.

Therefore, in addition to the above effects, there is an effect that the refrigerant flow rate of the third flow rate control device is secured as much as possible and a sufficient subcool in the heat exchange section can be obtained.

[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 (3)

[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; It is provided between the first connection pipe and the second connection pipe, and by switching the flow of the refrigerant, the heat source unit is always connected to the heat source device during operation. A connection pipe switching device for lowering the pressure of the first connection pipe and a high pressure for the second connection pipe interposed between the indoor units, and one end of which is connected to the second branch portion and the other end of which is the third flow rate. A bypass pipe connected to the first connection pipe via a control device, a fourth flow rate control device for communicating the second branch portion and the first connection pipe, each indoor unit and the second A heat exchanging unit for exchanging heat between a merging portion of indoor connecting pipes connecting the branching portions and an indoor connecting pipe and a downstream portion of the third flow control device of the bypass pipe; Pressure detection means provided between the second branch flow control device and the second flow control device, and a second pressure detection device provided between the second flow control device and the fourth flow control device. Means and the pressure difference detected by the first and second pressure detecting means is at least within a predetermined range. Serial third, fourth and a flow controller control means for controlling either the flow rate control device, an air conditioning apparatus, characterized in that co-operable configured cooling and heating. 2. When the flow rates of the third and fourth flow rate control devices are increased in a predetermined operation, the flow rate control device control means gives priority to the third flow rate control device. 1. The air conditioner according to 1. 3. In a predetermined operation, when the flow rates of the third and fourth flow rate control devices are decreased, the flow rate control device control means gives priority to the fourth flow rate control device. 1. The air conditioner according to 1.