JPH046373A - Air conditioner - Google Patents

Abstract

PURPOSE:To permit the selective cooling or heating operation of respective indoor machines individually and simultaneously by a method wherein a changeover valve is provided between the first and second connecting pipelines a heat source machine while the first connecting pipeline is permitted to be switched to a low pressure and the second connecting pipeline is permitted to be switched to a high pressure. CONSTITUTION:A relay machine E, accommodating a first branching unit 10, a second flow rate control device 13, a third flow rate control device 15 and a second branching unit 11, is interposed between a heat source machine and a plurality of sets of indoor machines B, C, D. The diameter of a first connecting pipeline 6 is made larger than the same of a second connecting pipeline 7 and a changeover valve 40 is provided between the first and second connecting pipelines of the heat source machine A while the first connecting pipeline 6 is permitted to be switched to a low pressure and the second connecting pipeline 7 is permitted to be switched to a high pressure.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a multi-room heat pump air conditioner in which a plurality of indoor units are connected to one heat source device, and in particular, The present invention relates to an air conditioner that can perform heating and cooling selectively, and can simultaneously perform cooling with one indoor unit and heating with the other indoor unit.

[Traditional Kihojutsu]

Conventionally, heat pump air conditioners have been common in which multiple indoor units are connected to one heat source unit using two pipes, a gas pipe and a liquid pipe, and each indoor unit performs heating and cooling operations. or all configured to provide cooling.

[Problem to be solved by the invention]

Conventional multi-room heat pump air conditioners are configured as described above, and only operate indoor units for cooling or heating. There were problems with heating or cooling where it was needed.

Particularly when installed in a large building, this poses a particular problem because the air conditioning load differs significantly between the interior and perimeter areas, or between general offices and rooms that are OAized such as computer rooms.

This invention was made to solve the above-mentioned problems. Multiple indoor units are connected to one heat source unit, and each indoor unit can selectively perform air conditioning and heating. The indoor unit can perform cooling and the other indoor unit can perform heating at the same time, and when installed in a large-scale building, it can be used for OA in interior and perimeter areas, general offices, computer rooms, etc. To provide a multi-room heat pump type air conditioner that can accommodate each room even if the air conditioning loads differ significantly in each room.

[Means to solve the problem]

This invention includes a compressor, a four-way switching valve, a heat exchanger on the heat source side,
One heat source device consisting of an accumulator, etc., and a plurality of indoor units consisting of an indoor heat exchanger, a first flow rate control device, etc. are connected via first and second connection pipes, and the above-mentioned a first branching section in which 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 connected to the other side of the indoor heat exchanger via the first flow rate control device and connected to the second connection pipe via the second flow rate control device; are connected via the second flow control device, further connecting the second branch and the first connection pipe via a fourth flow control device; and a bypass pipe connected to the first connection pipe via a third flow control device, the bypass pipe between the third flow control device and the first connection pipe, and the second connection pipe. a first heat exchange section that performs heat exchange between the connecting piping and the piping connecting the second flow rate control device; and a bypass piping between the third flow rate control device and the first connection piping. and a second heat exchange section that performs heat exchange between the first branch section, the second flow rate control device, the third flow rate control device, and the second branch section. A repeater having a built-in unit is interposed between the heat source device and the plurality of indoor units, and
The first connection pipe is configured to have a larger diameter than the second connection pipe, a switching valve is provided between the first and second connection pipes of the heat source device, the first connection pipe is set to a low pressure, It is characterized in that the second connection pipe can be switched to high pressure.

[For production]

In this invention, in the case of heating mainly in simultaneous cooling and heating operation, high-pressure gas refrigerant is introduced into each indoor unit to be heated from the heat source equipment side switching valve, the second connection pipe, and the first branch part. Thereafter, a portion of the refrigerant flows from the second branch into the indoor unit to be cooled, and then flows from the first branch into the first connection pipe. On the other hand, the remaining refrigerant passes through the fourth flow rate control device, joins with the refrigerant that has passed through the cooling indoor unit, and flows into the first connection pipe,
Return to the heat source machine. Further, in the process of circulating a part of the refrigerant from the second branch section to the first connection pipe via the bypass pipe, heat exchange is performed in the second heat exchange part to cool the refrigerant and sufficiently subcool the refrigerant. The increased amount of air flows into the indoor unit that is trying to cool the room.

In addition, in the case of cooling mainly, the high-pressure gas is exchanged with the heat source machine in an arbitrary amount of heat, and the separated gaseous refrigerant is sent to the first branch part from the heat source machine side switching valve and the second connection pipe. The air is introduced into the indoor unit to be heated through the air, performs heating, and flows into the second branch.

On the other hand, the separated liquid remaining refrigerant passes through the second flow rate adjustment device, joins with the refrigerant that has passed through the indoor unit that is intended to heat the air at the second branch, and flows into each indoor unit that is attempting to cool the room. After that, the air is guided from the first branch through the first connection pipe to the heat source equipment side switching valve and returned to the compressor. Furthermore, in the process of circulating a portion of the refrigerant from the second branch section to the first connection pipe via the bypass pipe, heat exchange is performed in the first and second heat exchange parts to cool the refrigerant sufficiently. subcooling is increased to flow into the indoor unit that is trying to cool the room.

Furthermore, in the case of only heating operation, the refrigerant is introduced into each indoor unit from the heat source equipment side switching valve through the second connection pipe and the first branch, heats, and then flows from the second branch to the first connection pipe. through and return to the heat source equipment side switching valve.

In the case of only cooling operation, the refrigerant is introduced into each indoor unit from the heat source equipment side switching valve through the second connection pipe and the second branch, cooled, and transferred from the first branch to the first connection pipe. and returns to the heat source machine side switching valve. Furthermore, in the process of circulating a portion of the refrigerant from the second branch section to the first connection pipe via the bypass pipe, heat exchange is performed in the first and second heat exchange parts to cool the refrigerant sufficiently. subcooling is increased to flow into the indoor unit that is trying to cool the room.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 is a diagram showing the overall configuration of an air conditioner according to an embodiment of the present invention, centering on the refrigerant. In addition, FIGS. 2 to 4 show operating states during cooling/heating operation in the embodiment shown in FIG. 1, and FIG.
Figures 3 and 4 show the operation of simultaneous heating and cooling operations. Figure 3 shows heating-dominant operation (when heating operation capacity is larger than cooling operation capacity), and Figure 4 shows cooling-dominant operation (when cooling operation capacity is larger than heating operation capacity). FIG. FIG. 5 is an overall configuration diagram centered on the refrigerant system of an air conditioner according to another embodiment of the present invention.

In this embodiment, a case will be described in which three indoor units are connected to one heat source device, or the same applies if two or more indoor units are connected.

In Figure 1, (A) is a heat source device, (B), (C), (
D) is an indoor unit connected in parallel to each other, each having the same configuration as described later. (E) includes a first branch, a second flow rate control device, a second branch,
A repeater that incorporates a gas-liquid separation device, a heat exchanger, a third flow rate control device, and a fourth flow rate control device.

(1) is a compressor, (2) is a four-way switching valve that switches the refrigerant flow direction of the heat source machine, (3) is a heat exchanger on the heat source machine side, (4)
is an accumulator, which is connected to the above devices (1) to (3) to constitute a heat source device (A). (5) is the three indoor heat exchangers, (6) is the thick first connection pipe that connects the four-way switching valve (2) of the heat source device (A) and the repeater (E), (6b), (
6c) and (6d) are indoor units (B), (C), respectively.
The indoor heat exchanger (5) of (D) and the repeater (E) are connected, and the first connection pipe on the indoor unit side corresponding to the first connection pipe (6), (7) is the heat source machine ( A) Heat source machine side heat exchanger (3
) and the repeater (E), and the second connection pipes (7b), (7c), and (7d) are thinner than the first connection pipes (7b), (7c), and (7d) of the indoor units (B), (C), and (D), respectively. Connect the indoor heat exchanger (5) and the repeater (E), and connect the second connection pipe (7
), and (8) connects the first connection pipes (6a), (6b), (6c) on the indoor unit side to the first connection pipe (6) or the first connection pipe (6c) on the indoor unit side. The three-way switching valve (9) is switchably connected to the connecting pipe (7) of No. 2, and the three-way switching valve (9) is connected in close proximity to the indoor heat exchanger (5).
) is the first flow control device that is controlled by the super heat amount during cooling and the subcool amount during heating, and is connected to the second connecting pipes (7b), (7c), and (7d) on the indoor unit side. Connected. α0) is the first connection pipe (6b) on the indoor unit side.
), (6c), and (6d) are switchably connected to the first connecting pipe (6) or the second connecting pipe (7) side. 02 is a second branch part consisting of the second connection pipes (7b), (7c), and (7d) on the indoor unit side and the second connection pipe, and 02 is provided in the middle of the second connection pipe (7). the gas-liquid separator, the gas phase part of which is connected to the first port (8a) of the three-way switching valve (8),
The liquid phase part is connected to the second branch part αυ. 03
04) is a second flow rate control device that can be opened and closed and is connected between the gas-liquid separator α2 and the second branch 01), and 04) is the second flow control device that is connected between the second branch 0D and the first connecting pipe (6). A5 is the third flow rate MII device installed in the middle of bypass piping 04), (16b), (+6c),
(+6d) is the third flow control device α of the bypass pipe α4
second connection pipes (7b), (7c), (7d) provided downstream of the
A third heat exchange section (16a) is provided downstream of the third flow rate control device α9 of the bypass pipe α4, and is connected to each indoor unit in the second branch αD. Second side connection pipes (7b), (7C), (7d)
a second heat exchange section that performs heat exchange with the confluence section of (19
+ is the flow control device α9 of the above VC3 with 0 leakage in the bypass piping
and a first heat exchange section that exchanges heat between piping that is provided downstream of the gas-liquid separator 0 and the second flow rate control device 03 and that is provided downstream of the second heat exchange section (16a). , 07) is a fourth flow rate control device that can be opened and closed and is connected between the second branch Q11 and the first connection pipe (6).

(32) is a third check valve provided between the heat source machine side heat exchanger (3) and the second connection pipe (7),
From the heat source machine side heat exchanger (3) to the second connection pipe (
Refrigerant flow is allowed only to 7). (33) connects the four-way switching valve (2) of the heat source device (A) and the first connection pipe (6).
), which allows refrigerant to flow only from the first connecting pipe (6) to the four-way switching valve (2). (34) is a fifth check valve provided between the four-way switching valve (2) of the heat source device (A) and the second connection pipe (A); ) to the second connection pipe (7).

(35) is a sixth check valve provided between the heat source machine side heat exchanger (3) and the first connection pipe (6),
From the first connection pipe (6) to the heat source equipment side heat exchanger (
Refrigerant flow is allowed only to 3). The third check valve (3
2) ~ Switching valve (40) with the sixth check valve (35)
Configure.

An embodiment of the invention configured in this manner will be described.

First, the case of only cooling operation will be explained using FIG.

That is, as shown by the solid line arrow in Fig. 2, the compressor (1)
The high temperature and high pressure refrigerant gas discharged from the four-way switching valve (2)
After passing through the heat source equipment side heat exchanger (3) for heat exchange and condensation, the third check valve (32), the second connection pipe (7),
It passes through the gas-liquid separator atr, the second flow rate control device o3 in that order, and then passes through the second branch part αυ, the second connection pipes (7b), (7c), and (7d) on the indoor unit side, and then passes through each indoor unit. Machine (B)
, (C) and (D). Then, each indoor unit (
The refrigerant flowing into B), (C), and (D) is reduced to a low pressure by the first flow rate control device (9), which is controlled by the amount of superheat at the outlet of each indoor heat exchanger (5), and then sent indoors. It exchanges heat with indoor air in the inner heat exchanger (5), evaporates, and gasifies to cool the room. Then, this refrigerant in a gas state is transferred to the first connection pipes (6b) and (6c) on the indoor unit side.
), (6d), the three-way switching valve (8), passing through the first branch part α■, the first connecting pipe (6), the fourth check valve (33),
The four-way switching valve (2) and accumulator (4) of the heat source machine (A)
) to form a circulation cycle in which the air is sucked into the compressor (1) to perform cooling operation. At this time, the 10th (8a) of the three-way switching valve (8) is closed, the 20th (8b) and the 30th (8th)
c) is open circuited. Also, at this time, the refrigerant is at low pressure in the first connection pipe (6) and high pressure in the second connection pipe (7), so it is inevitably the third check valve (32) and the fourth check valve ( 33
).

Furthermore, during this cycle, part of the refrigerant that has passed through the second flow rate control device a3 enters the bypass pipe (14), is reduced to a low pressure by the third flow rate control device, and is then transferred to the third heat exchange section. (+6b), (+6c), (16d) and the second connection pipes (7b), (7C), (7d) on each indoor unit side, and the second heat exchanger (16a) Branch part O1 of
) second connection pipes (7b), (7C), on each indoor unit side.
(7d), and the first heat exchange section 09)
The evaporated refrigerant exchanges heat with the refrigerant flowing into the second flow rate control device 03, enters the first connection pipe (6), the fourth check valve (button 3, and enters the four-way switching valve 2), is sucked into the compressor (1) via the accumulator (4).Meanwhile, the first, second and third heat exchange parts α9), (16a),
The second branch αυ is cooled by heat exchange with (+6b), (+6c), and (+66) and is sufficiently subcooled.
The refrigerant is used in the indoor units (B), (C), and
(D).

Next, the case of only heating operation will be described using FIG. 2. That is, as shown by the dotted line arrow in FIG. 2, the high temperature and high pressure refrigerant gas discharged from the compressor (1) passes through the four-way switching valve (2), the fifth check valve (34), and the second connection. The pipe (7) passes through the gas-liquid separator O2 and connects to the first branch part (10
), three-way switching valve (8), first connection pipe on the indoor unit side (6)
b), (6c), and (6d) in order, and each indoor unit (B)
, (C), and (D), it exchanges heat with indoor air, condenses and liquefies, and heats the room. Then, this liquid refrigerant passes through the first flow rate control device (9) that is controlled by the subcooling amount at the outlet of each indoor heat exchanger (5), and then passes through the second connection pipe ( 7b), (7c), (7d)
Flows into the second branch αυ, merges, and further passes through the fourth flow rate control device On, where the first flow rate control bag fI:
, (9) or the fourth flow rate control device αn to reduce the pressure to a low pressure two-phase state. The refrigerant, which has been reduced in pressure to a low pressure, passes through the first connection pipe (6) and passes through the sixth check valve (35).
From there, it flows into the heat exchanger (3) on the heat source side, exchanges heat, evaporates, becomes a gas, and is sucked into the compressor (11) through the four-way switching valve (2) and the accumulator (4), forming a circulation cycle. , perform heating operation. At this time, the three-way switching valve (8)
The 20th (8b) is a closed circuit, the 10th (8a) and the 30th (
8c) is open circuited. Also, at this time, the refrigerant is at low pressure in the first connection pipe (6) and high pressure in the second connection pipe (7), so it is inevitably the fifth check valve (34) and the sixth check valve ( 3
5).

A case in which heating is the main component in simultaneous cooling and heating operation will be explained using FIG. 3. Here, we will explain the case where two indoor units (B) and (C) are used for heating, and one indoor unit (D) is used for cooling.

That is, as shown by the solid line arrow in Fig. 3, the compressor (1)
The high temperature and high pressure refrigerant gas discharged from the four-way switching valve (2),
Passing through the fifth inverse ratio valve (34) and the second connection pipe (7),
It is sent to the repeater (E), passes through the gas-liquid separator α2, and then passes through the first branch αO), the three-way switching valve (8), and the first connection pipes (6b) and (6c) on the indoor unit side. The air flows into the indoor units (B) and (C) that are being heated, and is condensed and liquefied by exchanging heat with indoor air in the indoor heat exchanger (5).
Heat the room. The refrigerant in this liquid state is
It is controlled by the subcooling amount at the outlet of each indoor heat exchanger (5), passes through the first flow rate control device (9) which is in an almost fully open state, and is slightly depressurized before flowing into the second branch OI). and,
A part of this refrigerant is transferred to the second connection pipe (7d) on the indoor unit side.
, enters the indoor unit (D) that is being cooled, enters the first flow rate control device (9) controlled by the amount of superheat at the outlet of the indoor heat exchanger (5), and is depressurized, and then enters the indoor unit (D). It enters the heat exchanger (5), exchanges heat, evaporates, becomes a gas, cools the room, and flows into the first connection pipe (6) via the three-way switching valve (8).

On the other hand, other refrigerants try to cool the air by passing through the openable and closable fourth flow rate control bag fa07), which is controlled by the high pressure of the second connection pipe (7) and the intermediate pressure value of the second branch 0D. It joins with the refrigerant that has passed through the indoor unit (D) and passes through the thick first connection pipe (6) to the sixth check valve (35) of the heat source unit (A).
, flows into the heat exchanger (3) on the heat source side, exchanges heat, and becomes gaseous. Then, the refrigerant forms a circulation cycle in which the refrigerant is sucked into the compressor (1) through the four-way switching valve (2) and the accumulator (4) of the heat source device, and performs heating-dominant operation. At this time, the indoor heat exchanger (5
) and the evaporation pressure of the heat exchanger (3) on the heat source side become smaller due to switching to the thicker first connection pipe (6). Also, at this time, the indoor unit (B”l, (C)
The 20th (8b) of the three-way switching valve (8) connected to the indoor unit (D) is closed, the 10th (8a) and the 30th (8c) are open, and the three-way switching valve (8) connected to the indoor unit (D) is closed. ) is the 10th
(8a) is a closed circuit, 2nd port (8b) and 30th (8c)
is open. Furthermore, at this time, since the refrigerant is at low pressure in the first connection pipe (6) and high pressure in the second connection pipe (7), the refrigerant is inevitably passed through the fifth check valve (34) and the sixth check valve ( 35)
distributed to.

Also, during this cycle, some liquid refrigerant flows to the second branch 0.
Second connection pipes (7b), (7c), on each indoor unit side of υ
It enters the bypass pipe 04) from the confluence part of (7d), and enters the third
The flow rate control device 09 reduces the pressure to a low pressure, and the third heat exchange section (16b), (16c), (16d) connects the second connection pipes (7b), (7c), (7d) on each indoor unit side. and the second connection pipes (7b), (7c), (7
d) and the second heat exchanger in the first heat exchanger 09.
The evaporated refrigerant exchanges heat with the refrigerant flowing in from the flow rate control device a3, and enters the first connection pipe (6).
It flows into the sixth check valve (35) of the heat source device (A) and the heat exchanger (3) on the heat source device side, exchanges heat, and evaporates to become a gas.

Then, this refrigerant is transferred to the four-way switching valve (2) of the heat source device (A),
It is sucked into the compressor (1) via the accumulator (4). On the other hand, the first, second, and third heat exchange parts Q9), (16a
), (16b), (16c), and (16d), the refrigerant in the second branch part αυ, which has been cooled by heat exchange and has been sufficiently subcooled, flows into the indoor unit (D) to be cooled. A case in which cooling is the main component in simultaneous heating and cooling operation will be described with reference to FIG. 4. Here, the indoor unit (B),
A case will be explained in which two indoor units (C) are trying to cool the room, and one indoor unit (D) is trying to heat the room.

That is, as shown by the solid line arrow in Fig. 4, the compressor (1)
The high-temperature, high-pressure refrigerant gas discharged from the heat exchanger (3) on the heat source side exchanges heat in an arbitrary amount to become a two-phase high-temperature, high-pressure gas.
Passing through the third check valve (32) and the second connection pipe (7),
It is sent to the gas-liquid separator 0z of the repeater (Ilj), where it is separated into gaseous refrigerant and liquid refrigerant, and the separated gaseous refrigerant is transferred to the first branch section 00), the three-way switching valve (8)
, passes through the first connecting pipe (6d) on the indoor unit side, flows into the indoor unit (D) to be heated, exchanges heat with indoor air in the indoor heat exchanger (5), and condenses and liquefies. Heat the room. Furthermore, the first flow rate control device (which is controlled by the subcooling amount at the outlet of the indoor heat exchanger (5) and is in an almost fully open state)
9) and is slightly depressurized, and then flows into the second branch OD. On the other hand, the remaining liquid refrigerant separated by the gas-liquid separator 0■ is controlled by the high pressure of the second connection pipe (7) and the intermediate pressure value of the second branch OD, which allows the second flow rate to be freely opened and closed. The refrigerant flows into the second branch αD through the device 03 and joins with the refrigerant that has passed through the indoor unit (D) to be heated. Then, the second branch part αD, the second connection pipe on the indoor unit side (
7b), (7C), and each indoor unit (B), (C)
flows into. The refrigerant that has flowed into each indoor unit (B) and (C) is then reduced to a low pressure by the first flow rate control device # (9) that is controlled by the amount of superheat at the outlet of the indoor unit side heat exchanger (5). The air flows into the indoor heat exchanger (5), exchanges heat with indoor air, evaporates and becomes gas, and cools the room.

Furthermore, the refrigerant in the gas state is transferred to the first connection pipes (6b), (6c) on the indoor unit side, the three-way switching valve (8), and the first connection pipe (6b), (6c) on the indoor unit side.
The compressor (1) passes through the branch part αω of A circulation cycle is configured in which air is sucked into the air, and air-conditioning is mainly used. At this time, the second three-way switching valve (8) connected to the indoor units (B) and (C)
0 (8b) and 30th (8c) are open circuits, 10th (8a)
is closed, and the 10th (8a) and 30th (8c) of the three-way switching valve (8) connected to the indoor unit (D) are open,
The 20th (8b) is closed. Also, at this time, the refrigerant is at low pressure in the first connection pipe (6) and high pressure in the second connection pipe, so it inevitably flows into the third check valve (32) and the fourth check valve (33). circulate.

Furthermore, during this cycle, some liquid refrigerant flows to the second branch (
11) on the side of each indoor unit (7b), (7c)
), the third flow rate control device a! enters the bypass pipe CI4+ from the confluence part of (7d). The pressure is reduced to low pressure at step 19, and the third heat exchange section (16b), (+6c), (16d)
Then connect the second connection pipes (7b), (7C), (
7d), the second connection pipe (7b) on each indoor unit side of the second branch part 01) in the second heat exchange part (16a),
(7c) and (7d), and the second flow jl i'1i (J control device a3) in the first heat exchanger Cl9).
The evaporated refrigerant exchanges heat with the refrigerant flowing into the
It enters the first connection pipe (6), passes through the fourth check valve (33) of the heat source machine (A), the four-way switching valve (2) of the heat source machine (A), the accumulator (4), and then the compressor (] ) is inhaled.

On the other hand, the first, second, and third heat exchange parts a9), (16a)
, (16b), (16c), and (+6d), the second branch part a is cooled by heat exchange and sufficiently covered with subcles.
The refrigerant in l) is used in the indoor units (B) and (C) that are trying to cool the room.
).

In addition, in the above embodiment, a three-way switching valve (8) is provided to connect the first connection pipes (6b), (6c), (6d) on the indoor unit side,
Either it is switchably connected to the first connection pipe (6) or the second connection pipe (7), or it is connected to the second connection pipe (7) as shown in FIG.
Even if on-off valves such as two tensioners (30) and (3J) are provided and connected in a switchable manner as described above, similar effects can be obtained.

〔Effect of the invention〕

As explained above, the air conditioner of the present invention includes one heat source device including a compressor, a four-way switching valve, a heat exchanger on the heat source side, an accumulator, etc., an indoor heat exchanger, and a first flow rate control device. A plurality of indoor units consisting of devices, etc. are connected via first and second connection pipes, and one of the indoor heat exchangers of the plurality of indoor units is connected to the first connection pipe or, Second
a first branch part switchably connected to the connecting pipe of the plurality of indoor units, and a first branch part connected to the other of the indoor heat exchangers of the plurality of indoor units via the first flow rate control device; 2
A second branch section connected to the second connection pipe via the flow rate control device is connected via the second flow rate control device; The first connection pipe is connected to the first connection pipe via a fourth flow rate control device, and the bypass pipe is connected to the second branch portion and the first connection pipe via a third flow rate control device, A first pipe that exchanges heat between a bypass pipe between the third flow control device and the first connection pipe, and a pipe connecting the second connection pipe and the second flow control device. a heat exchange section, the first branch section, a second flow rate control device,
A relay machine incorporating a third flow rate control device and a second branch part is interposed between the heat source device and the plurality of indoor units, and the first connection pipe is connected to the second connection pipe. The pipe is configured to have a larger diameter than the pipe, and a switching valve is provided between the first and second connection pipes of the heat source device, so that the first connection pipe can be switched to low pressure and the second connection pipe to high pressure. wherein the second branch part and the first connection pipe are connected via a third flow rate control device, the bypass pipe being connected between the third flow rate control device and the first connection line; a first heat exchange section that performs heat exchange between the bypass pipe and the pipe connecting the second connection pipe and the second flow rate control device; and the third flow rate control unit and the first heat exchange unit. The second heat exchange part is provided for exchanging heat between the bypass pipe between the connecting pipe and the second branch part.

Therefore, it is possible to selectively use multiple indoor units, cooling one indoor unit and heating the other indoor unit at the same time. Moreover, subcooling is performed before being distributed to the indoor unit that is attempting to cool the air. Since the liquid refrigerant is sufficiently turned on and distributed to each indoor unit to be cooled, the distribution of the liquid refrigerant is improved, and a subcooling area at the inlet of the first flow rate control device is ensured, thereby improving reliability. Furthermore, in the case of only cooling operation and in the case of cooling mainly in simultaneous cooling and heating operation, the second
Even if the refrigerant flowing through the connecting pipe is in a two-phase state, it is cooled in the first heat exchange section, so the refrigerant always becomes a liquid refrigerant with sufficient subcooling at the inlet of the second flow rate control device. This makes it easier to control the flow and flow rate of the refrigerant in the second flow rate control device.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram centered on the refrigerant system of an air conditioner according to an embodiment of the present invention. Fig. 2 is a diagram showing the operating state of only cooling or heating in the embodiment shown in Fig. 1, and Fig. 3 is a diagram showing the operating state of only cooling or heating in the embodiment shown in Fig. 1. ), FIG. 4 is a diagram of the operating state of the cooling main unit (when the cooling operating capacity is larger than the heating operating capacity) of the embodiment shown in FIG. 1, and FIG.
The figure is an overall configuration diagram centered on the refrigerant system of an air conditioner according to another embodiment of the present invention. In the figure, (A) is a heat source machine, (B), (C), (1
)) is an indoor unit with the same configuration, (E) is a repeater,
(1) is the compressor, (2) is the four-way switching valve, (3) is the heat exchanger on the heat source side, (4) is the accumulator, (5) is the indoor heat exchanger, (6) is the first connection Piping, (6b), (6c
), (6d) is the second connection pipe on the indoor unit side, (7b),
(7c) and (7d) are the second connection pipes on the indoor unit side, (8
) is a three-way switching valve, (9) is a first flow control device, (10
) is the first branch part, 01) is the second branch part, q is the gas-liquid separation device, 03 is the second flow rate control device, (14) is the bypass piping, 09 is the third flow rate control device, (16a), (
+6b), (16c), (+6d) are the second and third heat exchange parts, 09) is the first heat exchange part, α force is the fourth flow rate control device, (30) and (31) are the electromagnetic Opening/closing valves such as valves, (3
2) is the third check valve, (33) is the fourth check valve, (34
) is the fifth check valve, (35) is the sixth check valve, (40)
is the switching valve on the heat source machine side. In addition, the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] One heat source device including a compressor, a four-way switching valve, a heat exchanger on the heat source side, an accumulator, etc., and a plurality of indoor units including an indoor heat exchanger, a first flow rate control device, etc. machine and the first
, connected via a second connection pipe, and 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. 1
and the other of the indoor heat exchangers of the plurality of indoor units via the first flow rate control device,
and a second branch section connected to the second connection pipe via the second flow rate control device, and further connected to the second branch section via the second flow rate control device. and the first connecting pipe connected via a fourth flow rate control device, and a bypass pipe connecting the second branch section and the first connecting line via a third flow rate control device. heat exchange between a bypass pipe between the third flow control device and the first connection pipe and a pipe connecting the second connection pipe and the second flow control device. a first heat exchange section that performs heat exchange, and a second heat exchange that performs heat exchange between the bypass piping between the third flow rate control device and the first connection piping, and the second branch section. A repeater having a built-in first branch, a second flow control device, a third flow control device, and a second branch is connected between the heat source device and the plurality of indoor units. While intervening,
The first connection pipe is configured to have a larger diameter than the second connection pipe, a switching valve is provided between the first and second connection pipes of the heat source device, the first connection pipe is set to a low pressure, An air conditioner capable of simultaneous heating and cooling operation, characterized in that the second connecting pipe can be switched to high pressure.