JPH04359767A - Air conditioner - Google Patents

Abstract

PURPOSE:To stably continue an operation by so setting that flows of refrigerant in first, second connecting tubes and a repeater become unidirectional even if a four-way switching valve is switched, and extending a bypass passage in the repeater at the time when a transient high pressure rises at the time of operating only room cooling. CONSTITUTION:A plurality of indoor units B-D connected in parallel with each other are connected to a heat source A having a compressor 1, a four-way switching valve 2, a heat exchanger 3, etc., through a repeater E. The repeater E connects a first branch unit 10 for connecting one of indoor side heat exchangers 5 of the plurality of units B-D to first connecting tubes 6b 6d or second connecting tubes 7b-7d, and a second branch unit 11 connected to the tubes 7b-7d through second flowrate controllers 9, 13, and connects the unit 11 to the tubes 6b-6d through a third flowrate controller 15. Here, the controller 15 so controls by opening determining means (not shown) as to increase the opening if a high pressure is transiently raised at the time of operating 'only room cooling'.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a multi-room heat pump air conditioner that connects a plurality of indoor units to one heat source unit. This invention relates to an air conditioner that can simultaneously perform cooling with one indoor unit and heating with the other indoor unit.

0002

BACKGROUND OF THE INVENTION The prior art of the present invention will be explained below. FIG. 8 is an overall configuration diagram centered on the refrigerant system of a conventional air conditioner capable of simultaneous cooling and heating operations disclosed in Japanese Patent Application Laid-Open No. 2-118372. Further, FIGS. 9 to 11 show operating states during cooling and heating operation in one embodiment of FIG. 8,
FIG. 9 is a diagram showing the operating state of only cooling or heating, and FIGS. 10 and 11 are diagrams showing the operation of simultaneous cooling and heating operation.
11 is an operation state diagram showing a heating-dominant mode (when the heating operating capacity is larger than the cooling operating capacity), and FIG. 11 is an operating state diagram showing a cooling-dominant mode (when the cooling operating capacity is larger than the heating operating capacity). In these figures, A is a heat source device, and B, C, and D are indoor units connected in parallel to each other as described later, and each has the same configuration. As will be described later, E is a repeater that incorporates a first branch, a second flow rate control device, and a second branch.

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, and 4 is an accumulator, which are connected to the above devices 1 to 3 and constitute heat source machine A. do. 5 is the three indoor heat exchangers, 6 is the first connection pipe that connects the four-way valve 2 of the heat source device A and the relay device E, 6b,
6c and 6d connect the indoor heat exchangers 5 of the indoor units B, C, and D, respectively, and the repeater E, and the first connection pipes on the indoor unit side corresponding to the first connection pipes 6, and 7 the heat source equipment. A second connection pipe connecting the heat source machine side heat exchanger 3 of A and the relay machine E, 7b,
7c and 7d are the second connection pipes on the indoor unit side that connect the indoor heat exchangers 5 of the indoor units B, C, and D and the repeater E and correspond to the second connection pipe 7, and 8 is the indoor unit side. The first connection pipes 6d, 6c, 6d and the three-way switching valve 9 switchably connected to the first connection pipe 6 or the second connection pipe 7 side are located close to the indoor heat exchanger 5. Connected heat exchanger 5
The first flow rate control device is controlled by a superheat amount during cooling and a subcool amount during heating on the exit side of the air conditioner, and is connected to second connection pipes 7b, 7c, and 7d on the indoor unit side. 1
0 is a first branch part consisting of a three-way switching valve 8 that is switchably connected to the first connection pipes 6b, 6c, and 6d on the indoor unit side and the first connection pipe 6 or the second connection pipe 7; 11
13 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 7, and 13 is an openable/closable part that connects the second connection pipe 7 and the second branch part 11. This is a second flow rate control device.

A conventional example of the present invention configured as described above will be explained. First, the case of only cooling operation will be described using FIG. 9. That is, as shown by the solid line arrow in the figure, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way switching valve 2, undergoes heat exchange in the heat exchanger 3 on the heat source side, and is condensed and liquefied. The connection pipes 7 of
, D. The refrigerant flowing into each of the indoor units B, C, and D is then reduced to a constant pressure by the first flow rate control device 9, exchanges heat with indoor air in the indoor heat exchanger 5, evaporates, and is gasified indoors. to cool down. Then, this refrigerant in a gas state is transferred to the first connection pipes 6b, 6c, 6 on the indoor unit side.
d, a circulation cycle in which the air is sucked into the compressor 1 via the three-way switching valve 8, the first branch 10, the first connecting pipe 6, the four-way valve 2 of the heat source device, and the accumulator 4 is configured to perform 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.
Port 8b and third port 8c are open.

Next, the case of only heating operation will be explained using FIG. That is, as shown by the dotted arrow in the figure, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way switching valve 2, the first connecting pipe 6, the first branch part 10,
Three-way switching valve 8, first connection pipes 6a, 6c on the indoor unit side,
6d, flows into each indoor unit B, C, and D, exchanges heat with indoor air, condenses and liquefies, and heats the room. Then, the refrigerant in the liquid state passes through the first flow rate control device 9 and the second connection pipes 7b, 7c, 7d on the indoor unit side.
It flows into the branch part 11 of
The pressure is reduced to a low pressure two-phase state by either one of the flow rate control devices 13. The refrigerant, which has been reduced in pressure to a low pressure, flows into the heat source side machine heat exchanger 3 of the heat source machine A through the second connection pipe 7, exchanges heat, and evaporates, and the refrigerant that has become a gas state is transferred to the four-way valve of the heat source machine. 2. Construct a circulation cycle in which the air is sucked into the compressor 1 via the accumulator 4, and perform heating operation. At this time, the three-way switching valve 8 is opened and closed in the same manner as in the case of only the cooling operation described above.

[0006] A case in which heating is the main component in simultaneous cooling and heating operation will be explained with reference to FIG. That is, as shown by the dotted arrow in the figure, the high temperature and high pressure refrigerant gas discharged from the compressor 1 is sent to the relay machine E through the first connection pipe 6.
Then, it passes through the first branch 10, the three-way switching valve 8, and the first connection pipes 6b and 6c on the indoor unit side in this order, and flows into each indoor unit B and C to be heated. It exchanges heat with indoor air and condenses into a liquid that heats the room. and,
This condensed and liquefied refrigerant passes through the first flow rate control device 9 which is in a substantially fully open state, is slightly depressurized, and flows into the second branch portion 11 . A part of this refrigerant passes through the first connection pipe 7d on the indoor unit side and enters the indoor unit D to be cooled, enters the first flow rate control device 9, is depressurized, and then passes through the indoor heat exchanger. 5, it exchanges heat, evaporates, becomes a gas, cools the room, and flows into the second connection pipe 7 via the three-way switching valve 8. On the other hand, other refrigerants flow into the second connection pipe 7 through the second branch part 11 and the second flow rate control device 13, join with the refrigerant that has passed through the indoor unit D to be cooled, and enter the heat source unit. It flows into the heat source side mechanical heat exchanger 3 of A, exchanges heat, and evaporates into a gas state. Then, the refrigerant is transferred to the four-way valve 2 of the heat source machine.
A circulation cycle is configured in which the air is sucked into the compressor 1 via the accumulator 4, and heating-based operation is performed. At this time, the first port 8a of the three-way switching valve 8 connected to the indoor units B and C is closed, the second port 8b and the third port 8c are open, and the indoor unit D
The second port 8b is closed, and the first port 8a and third port 8c are open.

[0007] A case in which cooling is the main component in simultaneous heating and cooling operation will be explained using FIG. 11. That is, as shown by the solid line arrow in the figure, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 undergoes heat exchange in an arbitrary amount in the heat exchanger 3 on the heat source side, and becomes a two-phase high-temperature, high-pressure state, and is transferred to the second connection. It is sent to repeater E via piping 7. Then, a part of this refrigerant passes through the first branch part 10, the three-way switching valve 8, and the first connection pipe 6d on the indoor unit side in this order, flows into the indoor unit D to be heated, and enters the indoor heat exchanger. At step 5, it exchanges heat with indoor air to condense and liquefy, heating the room. Furthermore, the first flow rate control device 9 is in an almost fully open state.
and flows into the second branch 11. On the other hand, the remaining refrigerant flows into the second branch portion 11 through the second flow rate control device 13 and joins with the refrigerant that has passed through the indoor unit D to be heated. The water then passes through the second branch 11 and the second connection pipes 7b and 7c on the indoor unit side in that order, and flows into each of the indoor units B and C. The refrigerant that has flowed into each of the indoor units B and C is then reduced to a low pressure by the first flow rate control device 9 and flows into the indoor heat exchanger 5, where it exchanges heat with the indoor air, evaporates, and gasifies into the room. to cool down. Furthermore, this refrigerant in a gas state is transferred to the first connection pipes 6b, 6c on the indoor unit side, the three-way switching valve 8, the first branch part 10,
A circulation cycle is configured in which the air is sucked into the compressor 1 via the first connection pipe 6, the four-way switching valve 2 of the heat source device, and the accumulator 4, and a cooling-based operation is performed. At this time, indoor units B, C,
The first ports 8a to 8c of the three-way switching valve 8 connected to D are opened and closed in the same manner as in the heating-based operation.

[0008]

[Problems to be Solved by the Invention] Since the conventional two-pipe air conditioner capable of simultaneous cooling and heating operation is configured as described above, the connection between the first and second connecting pipes and the repeater is controlled by switching the four-way switching valve. The flow of refrigerant was reversed, and the operating conditions suddenly changed every time the four-way switching valve was switched, and it took time for the system to stabilize. Further, there was a problem in that the pressure loss of the second connecting pipe was large during heating-based operation, and the capacity of the cooling indoor unit was insufficient.

[0009] This invention was made to solve the above-mentioned problems, and it is possible to unify the flow of refrigerant in the first and second connecting pipes and the repeater even when switching a four-way switching valve. The purpose is to obtain an air conditioner that can perform simultaneous cooling and heating operations with improved system stability. Further, by always using the first connection pipe, which is thicker than the second connection pipe, on the low-pressure side, it is an object of the present invention to reduce low-pressure pressure loss and suppress a decrease in the capacity of the cooling indoor unit.

[0010] Another purpose is to continue operation without stopping the operation by widening the bypass flow path in the repeater when the high pressure rises transiently due to a change in the number of operating units during operation only for cooling. It is something.

[0011]

[Means for Solving the Problems] An air conditioner according to the present invention includes one heat source machine including a compressor, a four-way switching valve, a heat exchanger on the heat source machine side, an accumulator, etc., an indoor heat exchanger, A plurality of indoor units including a first flow rate control device, 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 The first flow rate control device is connected to the first branching portion switchably connected to the connecting pipe or the second connecting pipe, and the other of the indoor heat exchangers of the plurality of indoor units. and a second branch section connected to the second connecting pipe via the second flow rate control device, and further connected to the second branch portion via the second flow rate control device, and connecting the second branch and the first connecting pipe via a third flow rate control device;
the first branch, the second flow control device, the third
A repeater incorporating a flow rate control device and the 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. A switching valve is provided between the first and second connecting pipes of the heat source device, so that the first connecting pipe can be switched to low pressure and the second connecting pipe can be switched to high pressure. In an air conditioner capable of simultaneous cooling and heating operation, a third control device that increases the opening degree of the third flow rate control device when high pressure transiently increases due to a change in the number of operating units during cooling only operation.
This is provided with means for determining the opening degree of the flow rate control device.

0012

[Operation] In this invention, when high pressure rises transiently during cooling-only operation, by increasing the opening degree of the second flow rate control device, the second connection pipe is connected to the second and second connection pipes in the repeater. The high pressure is lowered by widening the bypass flow path leading to the first connection pipe via the flow rate control device No. 3 to reduce flow path pressure loss and make it easier for the refrigerant to flow.

[0013]

【Example】

Example 1. Examples of the present invention will be described below. FIG. 1 is an overall configuration diagram centered on the refrigerant system of an air conditioner according to an embodiment of the present invention. In addition, Figures 2 to 4 show the operating states of the air conditioner shown in Figure 1 during cooling/heating operation. Figure 2 is an operational status diagram for cooling or heating only, and Figures 3 and 4 are for simultaneous cooling/heating operation. Fig. 3 is a diagram showing the operating state of the system mainly for heating (when the heating operating capacity is larger than the cooling operating capacity), and Fig. 4 is an operating state diagram showing mainly for cooling (when the cooling operating capacity is larger than the heating operating capacity). . In this embodiment, a case will be described in which three indoor units are connected to one heat source device, but the same applies to cases in which two or more indoor units are connected.

In FIG. 1, A is a heat source unit, and B, C, and D are indoor units connected in parallel to each other, each having the same configuration as will be described later. E indicates the first branch 10, the second flow control device 13, and the second branch 11, as will be described later.
, gas-liquid separation device 12, heat exchange parts 16a, 16b, 16c
, 16d, 19, a repeater incorporating a third flow rate control device 15 and a fourth flow rate control device 17. Further, 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, and 4 is an accumulator, which is connected to the compressor 1 via the four-way switching valve 2. There is. A heat source device A is configured by these. In addition, 5 is an indoor heat exchanger provided in three indoor units B, C, and D, and 6 is a four-way switching valve 2 of heat source device A and a relay device E via a fourth check valve 33, which will be described later. thick first connection piping, 6b, 6c
, 6d are indoor heat exchangers 5 of indoor units B, C, and D, respectively.
and the relay machine E, and a first connection pipe on the indoor unit side corresponding to the first connection pipe 6; This is a second connection pipe that is thinner than the first connection pipe that is connected via the check valve 32.

Further, 7b, 7c, and 7d connect the indoor heat exchangers 5 of the indoor units B, C, and D and the repeater E via the first flow rate control device 9, and the second connecting pipes 7 This is the second connection pipe on the indoor unit side corresponding to the above. 8 is a three-way switching valve that connects the first connection pipes 6b, 6c, and 6d on the indoor unit side to the first connection pipe 6 or the second connection pipe 7 side in a switchable manner. Reference numeral 9 denotes a first flow rate control device that is connected close to the indoor heat exchanger 5 and is controlled by the amount of super heat on the outlet side of the indoor heat exchanger 5 during cooling and by the amount of subcooling during heating. Second connection pipes 7b, 7c on the machine side,
Connected to 7d. 10 is the first connection pipe 6 on the indoor unit side
b, 6c, and 6d are connected to the first connection pipe 6 or the second connection pipe 7 in a switchable manner. Reference numeral 11 denotes a second branching section consisting of the second connection pipes 7b, 7c, and 7d on the indoor unit side and the second connection pipe 7. 12 is a gas-liquid separator installed in the middle of the second connection pipe 7, and its gas phase is connected to the first part of the three-way switching valve 8.
It is connected to the port 8a, and its liquid phase part is connected to the second branch part 11. 13 is a second flow rate control device (
Here, it is an electric expansion valve).

14 is a bypass pipe connecting the second branch 11 and the first connection pipe 6; 15 is a bypass pipe 14;
A third flow rate control device (here, an electric expansion valve) 16a is provided downstream of the third flow rate control device 15 provided in the middle of the bypass pipe 14, and a third flow rate control device 16a is provided in the middle of the bypass pipe 14. a second connection pipe 7b on each indoor unit side in 11;
The second part exchanges heat with the meeting parts 7c and 7d, respectively.
This is the heat exchange section. 16b, 16c, and 16d are respectively provided downstream of the third flow rate control device 15 provided in the middle of the bypass pipe 14, and are connected to the second connecting pipes 7b, 7c, and 16d on each indoor unit side in the second branch portion 11, respectively. This is a third heat exchange section that performs heat exchange with each other. Reference numeral 19 is provided in the bypass pipe 14 downstream of the third flow rate control device 15 and downstream of the second heat exchange section 16a, and is connected to the pipe connecting the gas-liquid separation device 12 and the second flow rate control device 13. A first heat exchange section 17 performs heat exchange between the second branch section 11 and the first connection pipe 6, and a fourth flow rate control device (here, an electric expansion valve).

On the other hand, 32 is a third check valve provided between the heat exchanger 3 on the heat source equipment side and the second connection pipe 7, and 32 is a third check valve provided between the heat exchanger 3 on the heat source equipment side and the second connection pipe 7. Refrigerant flow is allowed only to the connecting pipe 7 of No. 2. 33 is a fourth check valve provided between the four-way switching valve 2 of the heat source device A and the first connecting pipe 6, and only from the first connecting pipe 6 to the four-way switching valve 2 Allow refrigerant flow. 34 is a fifth check valve provided between the four-way switching valve 2 of the heat source device A and the second connecting pipe 7, and only from the four-way switching valve 2 to the second connecting pipe 7 Allow refrigerant flow. 35 is a sixth check valve provided between the heat source machine side heat exchanger 3 and the first connection pipe 6, and 35 is a sixth check valve provided between the heat source machine side heat exchanger 3 and the first connection pipe 6; Allow refrigerant flow only to the third, fourth, fifth, and sixth check valves 32, 33;
34 and 35 constitute a switching valve 40.

25 is a first pressure detection means provided between the first branch section 10 and the second flow rate control device 13;
26 is a second pressure detection means provided between the second flow rate control device 13 and the fourth flow rate control device 17, and 27 is a third pressure detection device provided in the first connection pipe 6. It is a means. Reference numeral 28 denotes bypass pipe outlet temperature detection means provided downstream of the first heat exchange section 19 of the bypass pipe 6. Further, 50 is a low pressure saturation temperature detection means provided in the middle of the pipe connecting the four-way switching valve 2 and the accumulator 4, and 18 is a low pressure saturation temperature detection means provided in the middle of the pipe connecting the compressor 1 and the four-way switching valve 2. This is a fourth pressure detection means.

Next, the operation will be explained. First, the case of only cooling operation will be described using FIG. 2. As shown by the solid line arrow in the figure, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the temperature detected by the low-pressure saturation temperature detection means 50 becomes a predetermined value passes through the four-way switching valve 2 and passes through the heat source After being condensed by exchanging heat with air in the side heat exchanger 3, the third
check valve 32, second connection pipe 7, gas-liquid separation device 12,
It passes through the second flow rate control device 13 in this order, then passes through the second branch 11 and the second connection pipes 7b, 7c, and 7d on the indoor unit side, and flows into each of the indoor units B, C, and D. Each indoor unit B, C,
The refrigerant flowing into D is reduced in pressure to a low pressure by the first flow control device 9, which is controlled by the amount of superheat at the outlet of each indoor heat exchanger 5, and is then heat exchanged with indoor air in the indoor heat exchanger 5. It evaporates and becomes gas, cooling the room.

The refrigerant in the gas state is transferred to the first connection pipes 6b, 6c, 6d on the indoor unit side, the three-way switching valve 8, and the first
branch part 10, first connection pipe 6, fourth check valve 33,
A circulation cycle is configured in which air is sucked into the compressor 1 through the four-way switching valve 2 and accumulator 4 of the heat source device A, and cooling operation is performed. At this time, the first port 8a of the three-way switching valve 8 is closed, and the second port 8b and third port 8c are opened. Further, at this time, the refrigerant inevitably flows to the third check valve 32 and the fourth check valve 33 because the first connection pipe 6 is under low pressure and the second connection pipe 7 is under high pressure. Also, during this cycle, a part of the refrigerant that has passed through the second flow rate control device 13 enters the bypass pipe 14, and the saturation temperature of the detected pressure of the third pressure detection means 27 and the bypass pipe outlet temperature detection means 28 are detected. It is controlled by the bypass piping outlet superheat amount calculated based on the detected temperature. The pressure is reduced to low pressure by the third flow rate control device 15, and the third
The heat exchange parts 16b, 16c, 16d of the second branch part 11
and the second connection pipes 7b, 7c, 7d on each indoor unit side of the second branch part 11 at the second heat exchange part 16a. , 7d, and the refrigerant flowing into the second flow rate control device 13 in the first heat exchange section 19, the evaporated refrigerant is transferred to the first connection pipe 6. , enters the fourth check valve 33, passes through the four-way switching valve 2 of the heat source device A, the accumulator 4, and is sucked into the compressor 1.

On the other hand, the first, second and third heat exchange sections 19,
16a, 16b, 16c, and 16d exchange heat and are cooled,
The refrigerant in the second branch section 11 that has been sufficiently subcooled flows into the indoor units B, C, and D that are to be cooled.

Next, the case of only heating operation will be explained using FIG. That is, as shown by the dotted line arrow in the figure, the high temperature and high pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the detected pressure of the fourth pressure detection means 18 becomes a predetermined value is transferred to the four-way switching valve 2. through a fifth check valve 34;
The second connection pipe 7 passes through the gas-liquid separator 12, the first branch 10, the three-way switching valve 8, and the first connection pipe 6 on the indoor unit side.
b, 6c, and 6d, and flows into each indoor unit B, C, and D, where it exchanges heat with indoor air, condenses and liquefies, and heats the room.

The refrigerant in the liquid state is controlled by the subcooling amount at the outlet of each indoor heat exchanger 5, passes through the first flow rate control device 9 that is almost fully open, and then passes through the second connection on the indoor unit side. The water flows into the second branch 11 from the pipes 7b, 7c, and 7d, joins together, and further passes through the fourth flow rate control device 17. Here, either the first flow rate control device 9 or the third and fourth flow rate control devices 15 and 17 is depressurized to a low pressure gas-liquid two-phase state. The refrigerant whose pressure has been reduced to a low pressure flows into the sixth check valve 35 of the heat source device A and the heat exchanger 3 on the heat source device side through the first connection pipe 6, exchanges heat with air, evaporates, and becomes a gas. , heat source machine A
A circulation cycle is constructed in which air is sucked into the compressor 1 through the four-way switching valve 2 and the accumulator 4, and heating operation is performed. At this time, the second port 8b of the three-way switching valve 8 is closed, and the first port 8a and third port 8c are opened. Further, at this time, the refrigerant inevitably flows to the fifth check valve 34 and the sixth check valve 35 because the first connection pipe 6 is under low pressure and the second connection pipe 7 is under high pressure.

Next, a case in which heating is the main component in simultaneous cooling and heating operation will be explained using FIG. 3. As shown by the dotted arrow in the figure, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the detected pressure of the fourth pressure detection means 18 becomes a predetermined value passes through the four-way switching valve 2. 5 check valve 34,
It is sent to the relay machine E through the second connection pipe 7, passes through the gas-liquid separation device 12, passes through the first branch part 10, the three-way switching valve 8, and the first connection pipes 6b and 6c on the indoor unit side in this order, It flows into each of the indoor units B and C that are attempting to heat the room, exchanges heat with indoor air in the indoor heat exchanger 5, and is condensed and liquefied to heat the room. This condensed and liquefied refrigerant is controlled by the amount of subcooling at the outlet of each indoor heat exchanger 5, and the first
The water passes through the flow rate control device 9, is slightly depressurized, and flows into the second branch 11.

A part of this refrigerant passes through the second connection pipe 7d on the indoor unit side, enters the indoor unit D to be cooled, and enters the first indoor unit D, which is controlled by the amount of superheat at the outlet of the indoor heat exchanger 5. After entering the flow control device 9 and being depressurized, it enters the indoor heat exchanger 5 where it exchanges heat and evaporates into a gas state to cool the room, and then passes through the first connection pipe 6d to the three-way switching valve 8. It flows into the first connecting pipe 6 through the. On the other hand, other refrigerants pass through a fourth flow rate control device 17 that is controlled 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 is within a predetermined range. , joins with the refrigerant that has passed through the indoor unit D to be cooled, passes through the thick first connection pipe 6, flows into the sixth check valve 35 of the heat source unit A, and the heat exchanger 3 on the heat source unit side, and the air It exchanges heat with and evaporates, becoming a gas.

This refrigerant constitutes a circulation cycle in which the heat source unit A is sucked into the compressor 1 through the four-way switching valve 2 and the accumulator 4, thereby performing heating-based operation. At this time, the difference in pressure between the evaporation pressure of the indoor heat exchanger 5 of the indoor unit D to be cooled and the pressure of the heat source device side heat exchanger 3 becomes small because the connection is switched to the thick first connection pipe 6. Also, at this time, the second port 8b of the three-way switching valve 8 connected to the indoor units B and C is closed, the first port 8a and the third port 8c are open, and the first port 8a of the indoor unit D is closed. , the second port 8b and the third port 8c are open circuited. Further, at this time, the refrigerant inevitably flows to the fifth check valve 34 and the sixth check valve 35 because the first connection pipe 6 is under low pressure and the second connection pipe 7 is under high pressure.

During this cycle, some of the liquid refrigerant flows through the second connecting pipes 7b, 7c, 7 on the indoor unit side of the second branch 11.
It enters the bypass piping 14 from the junction of d, is reduced to a low pressure by the third flow rate control device 15, and is transferred to the third heat exchange section 16.
b, 16c, and 16d between the second connecting pipes 7b, 7c, and 7d on each indoor unit side of the second branch part 11, and between each of the second branch parts 11 in the second heat exchange part 16a. No. 2 on the indoor unit side
The evaporated refrigerant exchanges heat with the refrigerant flowing in from the second flow rate control device 13 in the first heat exchange section 19 and with the meeting portion of the connecting pipes 7b, 7c, and 7d. It enters the heat source machine side heat exchanger 3 via the first connection pipe 6 and the sixth check valve 35, and after exchanging heat with air and evaporating it, the four-way switching valve 2 of the heat source machine A and the accumulator 4 through compressor 1
is inhaled. On the other hand, the first, second, and third heat exchange parts 19,
The second branch part 11 is cooled by heat exchange with 16a, 16b, 16c, and 16d, and is sufficiently subcooled.
The refrigerant flows into the indoor unit D that is being cooled.

Next, a case in which cooling is the main component in simultaneous heating and cooling operation will be described with reference to FIG. As shown by the solid line arrow in the figure, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 whose capacity is controlled so that the temperature detected by the low-pressure saturation temperature detection means 50 becomes a predetermined value is passed through the four-way switching valve 2 to the heat source. It flows into the machine-side heat exchanger 3 and exchanges heat with air, resulting in a gas-liquid two-phase high-temperature, high-pressure state. Thereafter, this two-phase high-temperature, high-pressure refrigerant is sent to the gas-liquid separation device 12 of the relay machine E via the third check valve 32 and the second connection pipe 7. Here, the gaseous refrigerant is separated into a gaseous refrigerant and a liquid refrigerant, and the separated gaseous refrigerant passes through the first branch part 10, the three-way switching valve 8, and the first connecting pipe 6d on the indoor unit side in this order, and attempts to heat the room. Flows into indoor unit D,
It is condensed and liquefied by exchanging heat with indoor air in the indoor heat exchanger 5,
Heat the room. Furthermore, it is controlled by the subcooling amount at the outlet of the 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 section 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 detection means 25 and the pressure detected by the second pressure detection means 26.
Indoor unit D that flows into the second branch part 11 and attempts to heat
It merges with the refrigerant that has passed through. It passes through the second branch part 11 and the second connection pipes 7b and 7c on the indoor unit side in this order, and each indoor unit B,
Flows into C. The refrigerant that has flowed into each indoor unit B and C is transferred to the indoor unit heat exchanger 5
After the pressure is reduced to a low pressure by the first flow rate control device 9 controlled by the amount of superheat at the outlet of the Cool down. Furthermore, the refrigerant in the gas state passes through the first connection pipes 6b and 6c on the indoor unit side, the three-way switching valve 8, and the first branch part 10, and then passes through the first connection pipe 6 and the fourth connection pipe.
A circulation cycle is configured in which air is sucked into the compressor 1 through the check valve 33 of the heat source device A, the four-way switching valve 2 of the heat source device A, and the accumulator 4, and air-conditioning-based operation is performed. Also, 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 8a is closed.
b and the third port 8c are open, and the second port 8 of the indoor unit D
b is a closed circuit, and the first port 8a and the third port 8c are open circuits. At this time, the refrigerant inevitably flows to the third check valve 32 and the fourth check valve 33 because the first connection pipe 6 is under low pressure and the second connection pipe 7 is under high pressure.

During this cycle, some of the liquid refrigerant flows through the second connecting pipes 7b, 7c, and 7c on the indoor unit side of the second branch 11.
7d enters the bypass pipe 14 from the meeting part, and is reduced to a low pressure by the third flow rate control device 15, and then transferred to the third heat exchange section 1.
6b, 16c, 16d between the second connecting pipes 7b, 7c, 7d on each indoor unit side of the second branch part 11, and the second
between the heat exchanger section 16a and the meeting section of the second connection pipes 7b, 7c, and 7d on each indoor unit side of the second branch section 11, and the second flow rate at the first heat exchange section 19. Heat exchange is performed with the refrigerant flowing into the control device 13, and the evaporated refrigerant enters the first connection pipe 6 and the fourth check valve 33, passes through the four-way switching valve 2 of the heat source device A and the accumulator 4, and is compressed. Inhaled into machine 1. On the other hand, the first, second and third heat exchange parts 19, 16a, 1
The refrigerant in the second branch section 11, which has been cooled by heat exchange in 6b, 16c, and 16d and has been sufficiently subcooled, flows into the indoor units B and C that are to be cooled.

Next, transient high pressure rise suppression control in the case of only cooling operation will be explained with reference to FIGS. 5 and 6. FIG. 5 is a block diagram of the high pressure rise suppression control according to the first embodiment, and FIG. 6 is a flowchart of the high pressure rise suppression control according to the first embodiment. In FIG. 5, reference numeral 61 denotes a first timer for measuring the time elapsed since the last control in order to periodically control the opening of the third flow rate control device 15, and 61 is a first timer that measures the time since the last control was performed, and the compressor 1 starts operating. Alternatively, it is cleared every time the opening degree control of the third flow rate control device 15 is performed. Reference numeral 62 denotes a bypass pipe outlet superheat amount calculating means for calculating the bypass pipe outlet superheat amount from the detected pressure of the third pressure detecting means 27 and the detected temperature of the bypass pipe outlet temperature detecting means 28. Reference numeral 63 denotes an opening determining means for determining the opening of the third flow rate control device 15 based on the output of the bypass pipe outlet superheat amount calculating means 62 and the detected pressure of the first pressure detecting means 25. Reference numeral 64 denotes a second timer that measures the time since the previous high pressure rise suppression control, and is cleared by the start of operation of the compressor 1 or the high pressure rise suppression control.

Next, the flow of the high pressure rise suppression control will be explained with reference to FIG. In step 71, the first pressure detection means 25
It is determined whether the detected pressure is greater than or equal to a predetermined value. If it is greater than or equal to the predetermined value, the process proceeds to step 78, and if it is less than the predetermined value, the process proceeds to step 72. In step 78, it is determined whether the second clocking means 64 has been clocking for a predetermined time period B or more. If the time is not being measured, proceed to step 72; if the time is being measured, proceed to step 72.
Proceed to step 79. In step 79, the data of the second timer 64 is cleared, and the process proceeds to step 76. In step 76, the opening degree of the third flow rate control device 15 is opened by a predetermined opening width, and then the process proceeds to step 77. In step 72, it is determined whether the first clocking means 61 has been clocking for a predetermined time A or more. If the clock is being counted, proceed to step 73;
If the time has not been counted yet, the process returns to step 71. In step 73, it is determined whether the amount of superheat at the outlet of the bypass pipe is greater than or equal to a predetermined amount. If the amount is equal to or greater than the predetermined amount, the process proceeds to step 74; otherwise, the process proceeds to step 75. Step 7
In step 4, the opening degree of the third flow rate control device 15 is increased according to the deviation of the superheat amount from the predetermined amount, and the process proceeds to step 77. In step 75, the opening degree of the third flow rate control device 15 is decreased depending on the deviation from the predetermined amount of superheat, and the process proceeds to step 77. In step 77, the time measurement data of the first time measurement means 61 is cleared, and the process returns to step 71.

Example 2. Note that in the first embodiment, a three-way switching valve 8 is provided to connect the first connection pipes 6b, 6c, and
6d is switchably connected to the first connection pipe 6 or the second connection pipe 7, but as shown in FIG. Similar effects can be obtained even if the connection is switchable.

[0034]

As explained above, the air conditioner according to the present invention includes one heat source device including a compressor, a four-way switching valve, a heat source side heat exchanger, an accumulator, etc., an indoor heat exchanger, A plurality of indoor units including a first flow rate control device, 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 The first flow rate control device is connected to the first branching portion switchably connected to the connecting pipe or the second connecting pipe, and the other of the indoor heat exchangers of the plurality of indoor units. and a second branch section connected to the second connecting pipe via the second flow rate control device, and further connected to the second branch portion via the second flow rate control device, and The second branch part and the first connecting pipe are connected via a third flow rate control device, and the first branch part, the second flow rate control device, the third flow rate control device and the second connection pipe are connected through a third flow rate control device. A repeater having a built-in branch part is interposed between the heat source device and the plurality of indoor units, and the first connecting pipe is configured to have a larger diameter than the second connecting pipe, and the first connecting pipe is configured to have a larger diameter than the second connecting pipe. A switching valve is provided between the first and second connecting pipes of the heat source equipment, and the first connecting pipe is configured to be able to be switched to low pressure and the second connecting pipe to high pressure, and can be operated only for cooling. When the high pressure rises transiently due to a change in the number of conveyed units, etc., the opening degree of the third flow rate control device is increased.By providing a means for determining the opening degree of the third flow rate control device, the opening degree of the third flow rate control device is increased. By widening the bypass flow path leading from the connecting pipe to the first connecting pipe via the second and third flow rate control devices, reducing the pressure loss in the flow path and making it easier for the refrigerant to flow, the high pressure is lowered and the operation is improved. Operation can be continued without stopping.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram centered on a refrigerant system of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram for explaining the operating state of only cooling and heating of the air conditioner according to the first embodiment of the present invention.

FIG. 3 is a refrigerant circuit diagram for explaining the heating-based operating state of the air conditioner according to the first embodiment of the present invention.

FIG. 4 is a refrigerant circuit diagram for explaining the cooling-based operating state of the air conditioner according to the first embodiment of the present invention.

FIG. 5 is a block diagram of high pressure rise suppression control of the air conditioner according to the first embodiment of the present invention.

FIG. 6 is a flowchart of high pressure rise suppression control of the air conditioner according to the first embodiment of the present invention.

FIG. 7 is an overall configuration diagram centered on the refrigerant system of an air conditioner according to a second embodiment of the present invention.

FIG. 8 is an overall configuration diagram centered on the refrigerant system of a conventional air conditioner.

9 is a refrigerant circuit diagram for explaining an operating state of only cooling or heating of the air conditioner shown in FIG. 8. FIG.

FIG. 10 is a refrigerant circuit diagram for explaining a heating-based operating state of the air conditioner shown in FIG. 8;

11 is a refrigerant circuit for explaining the cooling-based operating state of the air conditioner shown in FIG. 8; FIG.

[Explanation of symbols]

1 Compressor 2 Four-way switching valve 3 Heat source machine side heat exchanger 4 Accumulator 5 Indoor side heat exchanger 6 6b, 6c, 6d First connection pipe 7 7b, 7
c, 7d Second connection pipe 9 First flow control device 10 First branch 11 Second branch 12 Gas-liquid separation device 13 Second flow control device 14 Bypass piping 15 Third flow control device 17 Fourth flow rate control device 18 Fourth pressure detection means 25 First pressure detection means 26 Second pressure detection means 27 Third pressure detection means 28 Bypass piping outlet temperature detection means 50 Low pressure saturation temperature detection means 63 Third Flow rate control device opening determining means A Heat source machines B, C, D Indoor unit E Relay machine

Claims (1)

[Claims] Claim 1: One heat source device consisting of a compressor, a four-way switching valve, a heat exchanger on the heat source side, an accumulator, etc., and a plurality of indoor units consisting of an indoor heat exchanger, a first flow rate control device, etc. one of the indoor heat exchangers of the plurality of indoor units is connected to the first
The first flow rate control device is connected to the first branching portion switchably connected to the connecting pipe or the second connecting pipe, and the other of the indoor heat exchangers of the plurality of indoor units. and a second branch section connected to the second connecting pipe via the second flow rate control device, and further connected to the second branch portion via the second flow rate control device, and The second branch part and the first connecting pipe are connected via a third flow rate control device, the first branch part, the second flow rate control device,
A repeater incorporating the third flow rate control device and the 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 branch. A switching valve is provided between the first and second connecting pipes of the heat source device, so that the first connecting pipe can be switched to low pressure and the second connecting pipe to high pressure. In an air conditioner capable of simultaneous cooling and heating operation, if the high pressure rises transiently during cooling only operation, the third
An air conditioner comprising: third flow rate control device opening determining means for increasing the opening of the flow rate control device.