WO2023139713A1

WO2023139713A1 - Air conditioner

Info

Publication number: WO2023139713A1
Application number: PCT/JP2022/001911
Authority: WO
Inventors: 勇輝水野; 傑鳩村; 皓亮宮脇; 淳西尾; 祐治本村; 博紀鷲山
Original assignee: 三菱電機株式会社
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2023-07-27
Also published as: JPWO2023139713A1

Abstract

This air conditioner comprises a rectifier circuit and an inter-refrigerant heat exchanger. The rectifier circuit is provided with: a first valve that allows refrigerant in a second pipe to flow from a third point to a fourth point and prevents the reverse flow; a second valve that allows the refrigerant in a fourth pipe to flow from the fourth point to a second point and prevents the reverse flow; a third valve that allows the refrigerant in a third pipe to flow from the third point to a first point and prevents the reverse flow; and a fourth valve that allows the refrigerant in a first pipe to flow from the first point to the second point and prevents the reverse flow. An outdoor unit is provided with: a fifth valve that allows the refrigerant in the third pipe to flow from the first point to a sixth point between the first point and the third valve and prevents the reverse flow; a sixth valve that allows the refrigerant in the first pipe to flow from a fifth point between the first point and the fourth valve to the first point and can prevent the reverse flow; and a fifth pipe that connects the fifth point and the sixth point and causes the refrigerant to flow from the sixth point to the fifth point. The inter-refrigerant heat exchanger exchanges heat between the refrigerant flowing in the fifth pipe and the refrigerant flowing in the pipe that branches off from any of the points between the third valve and the fifth valve, between the fourth valve and the sixth valve, and between the sixth point and the fifth point and is connected between a first switching valve and the suction side of a compressor.

Description

air conditioner

The present disclosure relates to a two-pipe air conditioner in which the outdoor unit has a heat exchanger between refrigerants.

There is an air conditioner in which an outdoor unit and a repeater are connected by two connecting pipes (for example, see Patent Document 1). In the air conditioner described in Patent Document 1, the forward pipe and the return pipe that connect the outdoor unit and the repeater are unified in all operation modes by four check valves in the outdoor unit, and simultaneous cooling and heating operation is possible in a two-pipe system. Further, in the air conditioner described in Patent Document 1, the high-pressure refrigerant and the low-pressure refrigerant in the subcooling heat exchanger, which is a heat exchanger between refrigerants, flow counter-currently in cooling operation. Also, in heating operation, the high-pressure refrigerant and the low-pressure refrigerant in the subcooling heat exchanger flow in parallel.

International Publication No. 2012/101672 (see FIG. 10)

In a two-pipe air conditioner, in order to achieve "counterflow of heat exchangers between refrigerants in both cooling and heating operations", for example, as shown in Japanese Patent Application Laid-Open No. 2003-075026, four valves are required.

Therefore, in order to achieve both "counterflow refrigerant heat exchanger in both cooling and heating operation" and "two-pipe air conditioning system" by combining conventional technologies, four valves each, that is, a total of eight valves are required. However, if eight valves are installed in order to satisfy both of these two requirements, there is a problem that the outdoor unit casing becomes large.

The present disclosure has been made in view of the above circumstances, and aims to provide a two-pipe air conditioner equipped with an outdoor unit having a heat exchanger between refrigerants that can suppress the increase in size of the outdoor unit housing and that allows counterflow between refrigerants in both cooling and heating operations.

An air conditioner according to the present disclosure includes an outdoor unit that includes a compressor, a first switching valve, a first outdoor heat exchanger, and a first outdoor expansion valve; an indoor unit that cools or heats a room; a first pipe through which refrigerant flowing out of the outdoor unit and flowing into the indoor unit flows; and a second pipe through which the refrigerant flowing out of the indoor unit and flowing into the outdoor unit flows; and a rectifying circuit that determines the flow direction of the refrigerant that has flowed into the outdoor unit through the second pipe; a heat exchanger between refrigerants that cools the refrigerant flowing into the suction side of the compressor with the refrigerant branched from the refrigerant flowing in the rectifying circuit; a first pipe that connects the first outdoor heat exchanger and the first pipe; a second pipe that connects the second pipe and the first switching valve; A third pipe connecting the first point and the third point, and a fourth pipe connecting the second point and the fourth point, where the first point and the second point are arranged from the side, and the third point and the fourth point are arranged from the two points on the middle of the second pipe which are closer to the second pipe. a first valve provided in the fourth pipe to allow the refrigerant in the fourth pipe to flow from the fourth point to the second point and prevent reverse flow; a third valve provided in the third pipe to allow the refrigerant in the third pipe to flow from the third point to the first point and prevent reverse flow; and a third valve provided in the first pipe to allow the refrigerant in the first pipe to flow from the first point to the second point a fifth valve provided in the third pipe to allow the refrigerant in the third pipe to flow from the first point to a sixth point between the first point and the third valve and prevent reverse flow; and a fifth pipe that connects the fifth point and the sixth point so that the refrigerant flows from the sixth point to the fifth point. Heat exchange is performed between the refrigerant flowing in the pipe connected between and the refrigerant flowing in the fifth pipe.

In the air conditioner of the present disclosure, the heat exchanger between refrigerants exchanges heat between the refrigerant flowing through the pipe that branches from any point between the third valve and the fifth valve, between the fourth valve and the sixth valve, and between the sixth point and the fifth point and that is connected between the first switching valve and the suction side of the compressor, and the refrigerant flowing through the fifth pipe. According to the air conditioner of the present disclosure, the six valves of the first valve, the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve can counterflow the refrigerant in the heat exchanger between mediums. Therefore, it is possible to suppress an increase in the size of the outdoor unit housing.

1 is a refrigerant circuit diagram of an air conditioner according to Embodiment 1. FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant in operating state A in the air conditioner according to Embodiment 1. FIG. 3 is a refrigerant circuit diagram showing the flow of refrigerant in operating state B in the air conditioner according to Embodiment 1. FIG. 3 is a refrigerant circuit diagram showing the flow of refrigerant in operating state C in the air conditioner according to Embodiment 1. FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant in operating state D in the air conditioner according to Embodiment 1. FIG. FIG. 4 is a refrigerant circuit diagram and a water circuit diagram of an air conditioner according to Modification 1 of Embodiment 1. FIG. FIG. 4 is a refrigerant circuit diagram and a water circuit diagram in an operating state A in the air conditioner according to Modification 1 of Embodiment 1; FIG. 4 is a refrigerant circuit diagram and a water circuit diagram in an operating state B in the air conditioner according to Modification 1 of Embodiment 1; FIG. 10 is a refrigerant circuit diagram and a water circuit diagram in an operating state C in the air conditioner according to Modification 1 of Embodiment 1; FIG. 8 is a refrigerant circuit diagram and a water circuit diagram in an operating state D in the air conditioner according to Modification 1 of Embodiment 1; 2 is a refrigerant circuit diagram of an air conditioner according to Embodiment 2. FIG. 8 is a refrigerant circuit diagram showing the flow of refrigerant in operating state A in the air conditioner according to Embodiment 2. FIG. 8 is a refrigerant circuit diagram showing the flow of refrigerant in operating state B in the air conditioner according to Embodiment 2. FIG. 8 is a refrigerant circuit diagram showing the flow of refrigerant in operating state C in the air conditioner according to Embodiment 2. FIG. FIG. 10 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state D in the air conditioner according to Embodiment 2; FIG. 8 is a refrigerant circuit diagram and a water circuit diagram of an air conditioner according to Modification 1 of Embodiment 2; FIG. 10 is a refrigerant circuit diagram and a water circuit diagram in an operating state A in the air conditioner according to Modification 1 of Embodiment 2; FIG. 10 is a refrigerant circuit diagram and a water circuit diagram in an operating state B in the air conditioner according to Modification 1 of Embodiment 2; FIG. 10 is a refrigerant circuit diagram and a water circuit diagram in an operating state C in the air conditioner according to Modification 1 of Embodiment 2; FIG. 10 is a refrigerant circuit diagram and a water circuit diagram in an operating state D in the air conditioner according to Modification 1 of Embodiment 2;

An air conditioner according to an embodiment will be described below with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description is given only when necessary. The present disclosure may include any combination of configurations that can be combined among the configurations described in each of the following embodiments. Forms of components appearing throughout the specification are merely examples, and are not limited to the forms described in the specification. In particular, the combination of components is not limited only to the combinations in each embodiment, and the components described in other embodiments can be applied to other embodiments.

Embodiment 1.
<Configuration of air conditioner 100>
FIG. 1 is a refrigerant circuit diagram of an air conditioner 100 according to Embodiment 1. FIG. As shown in FIG. 1, the air conditioner 100 has an outdoor unit 101, a repeater 102, a first indoor unit 103a, a second indoor unit 103b and a third indoor unit 103c. The outdoor unit 101 and the repeater 102 are connected by two pipes, a forward pipe t10 and a return pipe t11.

Refrigerant flowing out from the outdoor unit 101 and flowing into the repeater 102 flows out to the forward pipe t10. The refrigerant that has flowed into the repeater 102 flows out of the repeater 102 and flows through the first indoor unit 101a, the second indoor unit 103b, and the third indoor unit 103c depending on the operating state. Refrigerant flowing out of the first indoor unit 101a, the second indoor unit 103b, and the third indoor unit 103c and flowing into the outdoor unit 101 via the relay unit 102 flows through the return pipe t11.

The repeater 102 and the first indoor unit 103a are connected by two pipes t12a and t13a. The repeater 102 and the second indoor unit 103b are connected by two pipes t12b and t13b. The repeater 102 and the third indoor unit 103c are connected by two pipes t12c and t13c.

<Outdoor unit 101>
The outdoor unit 101 includes a compressor 1, a first outdoor four-way valve 2a, a first outdoor heat exchanger 3a, a subcooling heat exchanger 4, a first outdoor expansion valve 5a, a second outdoor expansion valve 5b, a first check valve 6a, a second check valve 6b, a third check valve 6c, a fourth check valve 6d and a fifth check valve 6e.

Here, the "check valve" is a valve that has a valve that closes due to the pressure difference before and after the valve, and that allows flow only from the high pressure side to the low pressure side.

The compressor 1 compresses and discharges the refrigerant. The first outdoor four-way valve 2a switches the flow direction of the refrigerant discharged from the compressor 1 and outputs the refrigerant, thereby switching between cooling and heating. The first outdoor heat exchanger 3a exchanges heat between the refrigerant output from the first outdoor four-way valve 2a and the outside air.

The first outdoor four-way valve 2a is an example of a refrigerant channel switching device that switches the flow direction of the refrigerant. The refrigerant flow switching device may be composed of a combination of two-way valves or three-way valves. Further, when the air conditioner 100 is exclusively for cooling or only for heating and there is no need to switch the flow direction of the refrigerant, the refrigerant channel switching device may not be provided.

The first check valve 6a, the second check valve 6b, the third check valve 6c and the fourth check valve 6d constitute a rectifying circuit r. The rectifier circuit r determines the flow direction of the refrigerant flowing out from the outdoor unit 101 to the forward pipe t10 and the flow direction of the refrigerant flowing into the outdoor unit 101 through the return pipe t11.

The outdoor unit 101 has a first pipe t1, a second pipe t2, a third pipe t3, a fourth pipe t4 and a fifth pipe t5.

The first pipe t1 connects the first outdoor heat exchanger 3a and the forward pipe t10. The second pipe t2 connects the return pipe t11 and the first outdoor four-way valve 2a. Of the two points on the first pipe t1, from the side closer to the first outdoor heat exchanger 3a, the first point p1 and the second point p2, and from the two points on the second pipe t2, the third point p3 and the fourth point p4 from the side closer to the return pipe t11. The third pipe t3 connects the first point p1 and the third point p3. The fourth pipe t4 connects the second point p2 and the fourth point p4. The point between the fourth check valve 6d on the first pipe t1 and the first outdoor expansion valve 5a, which is the sixth valve, is the fifth point p5, and the point between the third check valve 6c and the fifth check valve 6e on the third pipe t3 is the sixth point p6. The fifth pipe t5 connects the fifth point p5 and the sixth point p6, and the refrigerant flows from the sixth point p6 to the fifth point p5. A sixth pipe t6 branches off from the fifth pipe t5 and connects between the first outdoor four-way valve 2a and the suction side of the compressor 1 .

The sixth pipe t6 may branch from the third pipe t3 between the third check valve 6c and the fifth check valve 6e and lead between the first outdoor four-way valve 2a and the suction side of the compressor 1. The sixth pipe t6 may be branched from the first pipe t1 or the third pipe t3 between the fourth check valve 6d and the first outdoor expansion valve 5a and may be led between the first outdoor four-way valve 2a and the suction side of the compressor 1.

The supercooling heat exchanger 4 cools the refrigerant flowing into the suction side of the compressor 1 with the refrigerant diverted from the refrigerant flowing to the rectifying circuit r. The subcooling heat exchanger 4 branches from between the sixth point p6 and the fifth point p5 and flows in the sixth pipe t6 that is connected between the first outdoor four-way valve 2a and the suction side of the compressor 1. Heat exchange is performed between the refrigerant flowing in the fifth pipe t5 and the refrigerant flowing from the sixth point p6 to the fifth point p5. In addition, the subcooling heat exchanger 4 may exchange heat between the refrigerant flowing in a pipe (not shown) branched from between the third check valve 6c and the fifth check valve 6e and connected between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing from the sixth point p6 to the fifth point p5 in the fifth pipe t5. The supercooling heat exchanger 4 may exchange heat between the refrigerant flowing in a pipe (not shown) branched from between the fourth check valve 6d and the first outdoor expansion valve 5a and connected between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing from the sixth point p6 to the fifth point p5 in the fifth pipe t5.

In Embodiment 1, the fifth check valve 6e is added to the rectifying circuit r, and the first outdoor expansion valve 5a is used to counterflow the refrigerant flowing through the supercooling heat exchanger 4 in cooling and heating.

The first check valve 6a of the rectifier circuit r is provided in the second pipe t2, allows the refrigerant in the second pipe t2 to flow from the third point p3 to the fourth point p4, and prevents it from flowing in the opposite direction. The second check valve 6b is provided in the fourth pipe t4, allows the refrigerant in the fourth pipe t4 to flow from the fourth point p4 to the second point p2, and prevents the refrigerant from flowing in the opposite direction. The third check valve 6c is provided in the third pipe t3, allows the refrigerant in the third pipe t3 to flow from the third point p3 to the first point p1, and prevents the refrigerant from flowing in the opposite direction. The fourth check valve 6d is provided in the first pipe t1, allows the refrigerant in the first pipe t1 to flow from the first point p1 to the second point p2, and prevents the refrigerant from flowing in the opposite direction.

The fifth check valve 6e is provided in the third pipe t3 and allows the refrigerant in the third pipe t3 to flow from the first point p1 to the sixth point p6 between the first point p1 and the third check valve 6c, and prevents it from flowing in the opposite direction.

The first outdoor expansion valve 5a adjusts the pressure of the refrigerant flowing through the first pipe t1. The first outdoor expansion valve 5a is provided in the first pipe t1, and the refrigerant in the first pipe t1 can be allowed to flow from the fifth point p5 between the first point p1 and the fourth check valve 6d to the first point p1, and can be prevented from flowing in the opposite direction. It is possible to allow the flow from the point p5 to the first point p1 and prevent the reverse flow. The first outdoor expansion valve 5a of the present embodiment allows the flow from the fifth point p5 between the first point p1 and the fourth check valve 6d to the first point p1 due to the pressure difference across the first outdoor expansion valve 5a in a specific operating state (operating state B described later), and prevents the reverse flow.

The first outdoor expansion valve 5a reduces the pressure of the refrigerant flowing from the fifth point p5 to the first point p1 during heating operation, and is closed so that the refrigerant does not flow during cooling operation.

The second outdoor expansion valve 5b is provided in the sixth pipe t6, allowing the refrigerant in the sixth pipe t6 to flow from between the sixth point p6 and the fifth point p5 to the seventh point p7, and can prevent the refrigerant from flowing in the opposite direction. The second outdoor expansion valve 5b adjusts the pressure of the refrigerant flowing through the sixth pipe t6.

<Relay machine 102>
The repeater 102 includes a first on-off valve 7a, a second on-off valve 7b, a first three-way valve 8a, a second three-way valve 8b and a third three-way valve 8c. The first on-off valve 7a, the second on-off valve 7b, the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c determine the flow path through which the refrigerant flowing through the forward pipe t10 flows into the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c, depending on the operating state. In addition, the first on-off valve 7a, the second on-off valve 7b, the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c determine the flow path of the refrigerant flowing out of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c until it flows into the return pipe t11.

The first three-way valve 8a has a first port connected to the first indoor heat exchanger 9a, a second port connected to the forward pipe t10 and the first on-off valve 7a, and a third port connected to the return pipe t11 and the second on-off valve 7b. The second three-way valve 8b has a first port connected to the second indoor heat exchanger 9b, a second port connected to the forward pipe t10 and the first on-off valve 7a, and a third port connected to the return pipe t11 and the second on-off valve 7b. The third three-way valve 8c has a first port connected to the third indoor heat exchanger 9c, a second port connected to the forward pipe t10 and the first on-off valve 7a, and a third port connected to the return pipe t11 and the second on-off valve 7b.

The forward pipe t10 is connected to a pipe that connects to the first on-off valve 7a, the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c. The return pipe t11 is connected to a pipe connected to the second on-off valve 7b, the first three-way valve 8a, the second three-way valve 8b and the third three-way valve 8c.

<Indoor unit>
The first indoor unit 103a has a first indoor heat exchanger 9a and a first indoor expansion valve 10a connected to the first indoor heat exchanger 9a. The second indoor unit 103b has a second indoor heat exchanger 9b and a second indoor expansion valve 10b connected to the second indoor heat exchanger 9b. The third indoor unit 103c has a third indoor heat exchanger 9c and a third indoor expansion valve 10c connected to the third indoor heat exchanger 9c.

The first indoor heat exchanger 9a is connected to the first port of the first three-way valve 8a by a pipe t13a. The first indoor expansion valve 10a is connected to the first on-off valve 7a and the second on-off valve 7b of the repeater 102 by a pipe t12a. The second indoor heat exchanger 9b is connected to the first port of the second three-way valve 8b by a pipe t13b. The second indoor expansion valve 10b is connected to the first on-off valve 7a and the second on-off valve 7b of the repeater 102 by pipes t12a and t12b. The third indoor heat exchanger 9c is connected to the first port of the third three-way valve 8c by a pipe t13c. The third indoor expansion valve 10c is connected to the first on-off valve 7a and the second on-off valve 7b of the repeater 102 by pipes t12a and t12c.

<Control device 200>
The control device 200 controls the compressor 1 of the outdoor unit 101, the first outdoor four-way valve 2a, the first outdoor expansion valve 5a, the second outdoor expansion valve 5b, the first check valve 6a, the second check valve 6b, the third check valve 6c, the fourth check valve 6d and the fifth check valve 6e according to the operating state of the air conditioner 100.

The control device 200 controls the first on-off valve 7a, the second on-off valve 7b, the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c of the repeater 102 according to the operating state of the air conditioner 100.

The control device 200 controls the first indoor expansion valve 10a of the first indoor unit 103a, the second indoor expansion valve 10b of the second indoor unit 103b, and the third indoor expansion valve 10c of the third indoor unit 103c according to the operating state of the air conditioner 100.

Of the operating states, "operating state A" is the operating state when all of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are performing cooling operation. In "operating state B", some of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c perform cooling operation, and some or all of the others perform heating operation. In addition, "operating state B" is an operating state in which the cooling load of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is greater than the heating load of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c. In "operating state C", some of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are in cooling operation, and the other part or all are in heating operation. In addition, "operating state C" is an operating state in which the heating load of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is greater than the cooling load of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c. "Operating state D" is an operating state when all of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c perform the heating operation.

In the case of "operating state A", the control device 200 switches the first outdoor four-way valve 2a to the cooling side, closes the first outdoor expansion valve 5a, opens the second outdoor expansion valve 5b, opens the first on-off valve 7a, and closes the second on-off valve 7b. When the operating state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is cooling operation, the control device 200 opens the first port, closes the second port, and opens the third port of the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c.

In the case of "operating state B", the control device 200 switches the first outdoor four-way valve 2a to the cooling side, opens the first outdoor expansion valve 5a, closes the second outdoor expansion valve 5b, closes the first on-off valve 7a, and closes the second on-off valve 7b. When the state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is the operating state B, the control device 200 opens the first port, the second port, and the third port of the first three-way valve 8a of the first indoor unit 103a that is performing the heating operation. The first port of the second three-way valve 8b of the second indoor unit 103b that is performing cooling operation is opened, the second port is closed, and the third port is opened. The first port, the second port and the third port of the third three-way valve 8c of the third indoor unit 103c, which is in cooling operation, are opened.

In the case of "operating state C", the control device 200 switches the first outdoor four-way valve 2a to the heating side, opens the first outdoor expansion valve 5a, opens the second outdoor expansion valve 5b, closes the first on-off valve 7a, and opens the second on-off valve 7b. When the state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is the operating state C, the control device 200 opens the first port, the second port, and the third port of the first three-way valve 8a of the first indoor unit 103a that is performing the heating operation. The first port, the second port, and the third port of the second three-way valve 8b of the second indoor unit 103b that is performing the heating operation are opened. The first port, the second port and the third port of the third three-way valve 8c of the third indoor unit 103c, which is in cooling operation, are opened.

In the case of "operating state D", the control device 200 switches the first outdoor four-way valve 2a to the heating side, opens the first outdoor expansion valve 5a, opens the second outdoor expansion valve 5b, closes the first on-off valve 7a, and closes the second on-off valve 7b. When the operating state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is heating operation, the control device 200 opens the first port, the second port, and the third port of the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c.

When the processing circuit of the control device 200 is dedicated hardware, the processing circuit is, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Each functional unit implemented by the processing circuit may be implemented by separate hardware, or each functional unit may be implemented by one piece of hardware. When the processing circuit of the control device 200 is a CPU, each function executed by the processing circuit is implemented by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in the storage unit. The CPU implements each function of the processing circuit by reading and executing a program stored in the storage unit. A part of the functions of the processing circuit may be realized by dedicated hardware, and a part thereof may be realized by software or firmware.

<Operation of air conditioner 100>
The operation of the air conditioner 100 of Embodiment 1 will be described. FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant in operating state A in the air conditioner 100 according to Embodiment 1. As shown in FIG. FIG. 3 is a refrigerant circuit diagram showing the flow of refrigerant in operating state B in the air conditioner 100 according to Embodiment 1. As shown in FIG. FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant in operating state C in the air conditioner 100 according to Embodiment 1. As shown in FIG. FIG. 5 is a refrigerant circuit diagram showing the flow of refrigerant in operating state D in the air conditioner 100 according to Embodiment 1. As shown in FIG. 2, 3, 4 and 5, the arrows indicate the direction of coolant flow.

(Operating state A: full cooling operation)
FIG. 2 shows a state in which all of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are performing cooling operation.

In operating state A, the main circuit and three bypass circuits are formed. As shown in FIG. 2, in the main circuit, the refrigerant flows through the compressor 1, the first outdoor four-way valve 2a, the first outdoor heat exchanger 3a, the fifth check valve 6e, the subcooling heat exchanger 4, the fourth check valve 6d, the first on-off valve 7a, the first indoor expansion valve 10a, the first indoor heat exchanger 9a, the first three-way valve 8a, the first check valve 6a, the first outdoor four-way valve 2a, and the compressor 1 again.

In the first bypass circuit, the refrigerant branched from between the subcooling heat exchanger 4 of the main circuit and the fourth check valve 6d is a pipe t6 between the first outdoor four-way valve 2a and the suction side of the compressor 1. The refrigerant flowing through the pipe t6 flows through the second outdoor expansion valve 5b and the supercooling heat exchanger 4 in that order, and joins between the first outdoor four-way valve 2a of the main circuit and the suction side of the compressor 1. In the second bypass circuit, the refrigerant branched from between the first on-off valve 7a and the first indoor expansion valve 10a of the main circuit flows in the order of the second indoor expansion valve 10b, the second indoor heat exchanger 9b, and the second three-way valve 8b, and joins between the first three-way valve 8a and the first check valve 6a of the main circuit. In the third bypass circuit, the refrigerant branched from between the first on-off valve 7a and the first indoor expansion valve 10a of the main circuit flows in the order of the third indoor expansion valve 10c, the third indoor heat exchanger 9c, and the third three-way valve 8c, and joins between the first three-way valve 8a and the first check valve 6a of the main circuit.

(Operating state B: cooling and heating mixed operation, cooling load > heating load)
FIG. 3 shows a state in which the first indoor unit 103a is in heating operation, and the second indoor unit 103b and third indoor unit 103c are in cooling operation.

In operating state B, a main circuit and two bypass circuits are formed. As shown in FIG. 3, in the main circuit, the compressor 1, the first outdoor four-way valve 2a, the first outdoor heat exchanger 3a, the fifth check valve 6e, the supercooling heat exchanger 4, the fourth check valve 6d, the first three-way valve 8a, the first indoor heat exchanger 9a, the first indoor expansion valve 10a, the second indoor expansion valve 10b, the second indoor heat exchanger 9b, the second three-way valve 8b, the first check valve 6a, the first outdoor Refrigerant flows through the four-way valve 2a and then through the compressor 1 again.

In the first bypass circuit, the refrigerant branched from between the first outdoor heat exchanger 3a and the fifth check valve 6e of the main circuit flows into the first outdoor expansion valve 5a and joins between the subcooling heat exchanger 4 of the main circuit and the fourth check valve 6d. In the second bypass circuit, the refrigerant branched from between the first indoor expansion valve 10a and the second indoor expansion valve 10b of the main circuit flows through the third indoor expansion valve 10c, the third indoor heat exchanger 9c, the pipe t13c, and the third three-way valve 8c in that order, and joins the refrigerant from the second three-way valve 8b of the main circuit.

(Operating state C: cooling and heating mixed operation, heating load > cooling load)
FIG. 4 shows a state in which the first indoor unit 103a and the second indoor unit 103b are in heating operation, and the third indoor unit 103c is in cooling operation.

In operating state C, as shown in FIG. 4, a main circuit and two bypass circuits are formed. In the main circuit, the compressor 1, the first outdoor four-way valve 2a, the second check valve 6b, the first three-way valve 8a, the first indoor heat exchanger 9a, the first indoor expansion valve 10a, the third indoor expansion valve 10c, the third indoor heat exchanger 9c, the third three-way valve 8c, the third check valve 6c, the subcooling heat exchanger 4, the first outdoor expansion valve 5a, the first outdoor heat exchanger 3a, the first outdoor four-way valve 2a, The refrigerant flows in order of the compressor 1 again.

In the first bypass circuit, the refrigerant branched from between the second check valve 6b and the first three-way valve 8a of the main circuit flows through the second three-way valve 8b, the second indoor heat exchanger 9b, and the second indoor expansion valve 10b in that order, and joins between the first indoor expansion valve 10a and the third indoor expansion valve 10c of the main circuit. In the second bypass circuit, the refrigerant branched from between the subcooling heat exchanger 4 of the main circuit and the first outdoor expansion valve 5a flows to the second outdoor expansion valve 5b, and joins between the first outdoor four-way valve 2a of the main circuit and the compressor 1.

(Operating state D: All heating operation)
FIG. 5 shows a state in which all of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are performing heating operation.

In operating state D, the main circuit and three bypass circuits are formed. As shown in FIG. 5, in the main circuit, the refrigerant flows through the compressor 1, the first outdoor four-way valve 2a, the second check valve 6b, the first three-way valve 8a, the first indoor heat exchanger 9a, the first indoor expansion valve 10a, the second on-off valve 7b, the third check valve 6c, the subcooling heat exchanger 4, the first outdoor expansion valve 5a, the first outdoor heat exchanger 3a, the first outdoor four-way valve 2a, and the compressor 1 again.

In the first bypass circuit, the refrigerant branched from between the second check valve 6b and the first three-way valve 8a of the main circuit flows through the second three-way valve 8b, the second indoor heat exchanger 9b, and the second indoor expansion valve 10b in that order, and joins between the first indoor expansion valve 10a and the second on-off valve 7b of the main circuit. In the second bypass circuit, the refrigerant branched from between the second check valve 6b and the first three-way valve 8a of the main circuit flows in the order of the third three-way valve 8c, the third indoor heat exchanger 9c, and the third indoor expansion valve 10c, and joins between the first indoor expansion valve 10a and the second on-off valve 7b of the main circuit. In the third bypass circuit, the refrigerant branched from between the supercooling heat exchanger 4 and the first outdoor expansion valve 5a of the main circuit flows to the second outdoor expansion valve 5b and the supercooling heat exchanger 4, and joins between the first outdoor four-way valve 2a and the compressor 1 of the main circuit.

<Modification 1>
In Modification 1 of Embodiment 1, two types of heat media, refrigerant and water, form circuits independently without being mixed, and only heat is exchanged through the first refrigerant-water heat exchanger 12a and the second refrigerant-water heat exchanger 12b. For the first refrigerant-water heat exchanger 12a and the second refrigerant-water heat exchanger 12b, for example, plate heat exchangers, shell-and-tube heat exchangers, or the like are used.

FIG. 6 is a refrigerant circuit diagram and a water circuit diagram of the air conditioner 100 according to Modification 1 of Embodiment 1. FIG. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. In Modification 1, the configurations of the repeater 102, the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c in the air conditioner 100 of the first embodiment are different.

The repeater 102 includes a first on-off valve 7a, a second on-off valve 7b, a first refrigerant-water heat exchanger 12a, a second refrigerant-water heat exchanger 12b, a first relay four-way valve 13a, a second relay four-way valve 13b, a first pump 14a, a second pump 14b, a first mixed flow three-way valve 15a, a second mixed flow three-way valve 15b, a third mixed flow three-way valve 15c, and a first branch flow three-way valve 1. 6a, a second three-way diverter valve 16b and a third three-way diverter valve 16c.

The first on-off valve 7a is connected to the forward pipe t10. The first on-off valve 7a is connected to the second on-off valve 7b, the first relay expansion valve 11a and the second relay expansion valve 11b. The second on-off valve 7b is connected to the return pipe t11. The second on-off valve 7b is connected to the first on-off valve 7a, the first relay expansion valve 11a and the second relay expansion valve 11b.

The first relay expansion valve 11a is connected to the first on-off valve 7a, the second on-off valve 7b and the second relay expansion valve 11b. The first relay expansion valve 11a adjusts the pressure of the refrigerant flowing through the first refrigerant-water heat exchanger 12a.

The second relay expansion valve 11b is connected to the first on-off valve 7a, the second on-off valve 7b and the first relay expansion valve 11a. The second relay expansion valve 11b adjusts the pressure of the refrigerant flowing through the second refrigerant-water heat exchanger 12b.

The first refrigerant-water heat exchanger 12a is connected to the first relay expansion valve 11a and the first relay four-way valve 13a, and exchanges heat between the refrigerant flowing out from the forward pipe t10 of the outdoor unit 101 and water as a heat medium. The first refrigerant-water heat exchanger 12b is connected to the second relay expansion valve 11b and the second relay four-way valve 13b, and exchanges heat between the refrigerant flowing out from the forward pipe t10 of the outdoor unit 101 and water as a heat medium.

The first relay four-way valve 13a is connected to the forward pipe t10, the first refrigerant-water heat exchanger 12a and the return pipe t11, and switches the flow of refrigerant flowing out of the forward pipe t10. The second relay four-way valve 13b is connected to the forward pipe t10, the second refrigerant-water heat exchanger 12b, and the return pipe t11, and switches the flow of refrigerant flowing out of the forward pipe t10.

The discharge part of the first pump 14a is connected to the first refrigerant-water heat exchanger 12a. The first pump 14a applies pressure to the heat medium flowing through the first refrigerant-water heat exchanger 12a. The discharge of the second pump 14b is connected to the second refrigerant-water heat exchanger 12b. The second pump 14b applies pressure to the heat medium flowing through the second refrigerant-water heat exchanger 12b.

The first mixed flow three-way valve 15a is connected between the first refrigerant-water heat exchanger 12a, the second refrigerant-water heat exchanger 12b, and the first indoor heat exchanger 9a. The second mixed flow three-way valve 15b is connected between the first refrigerant-water heat exchanger 12a, the second refrigerant-water heat exchanger 12b, and the second indoor heat exchanger 9b. The third mixed flow three-way valve 15c is connected between the first refrigerant-water heat exchanger 12a, the second refrigerant-water heat exchanger 12b and the third indoor heat exchanger 9c.

The first diverting three-way valve 16a is connected between the second pump 14b, the first indoor heat exchanger 9a, and the first pump 14a. A second diverting three-way valve 16b is connected between the second pump 14b, the second indoor heat exchanger 9b and the first pump 14a. A third diverting three-way valve 16c is connected between the second pump 14b, the third indoor heat exchanger 9c and the first pump 14a.

The first mixed flow three-way valve 15a, the second mixed flow three-way valve 15b and the third mixed flow three-way valve 15c are connected to each other. The first flow dividing three-way valve 16a, the second flow dividing three-way valve 16b and the third flow dividing three-way valve 16c are connected to each other.

The first mixed flow three-way valve 15a, the second mixed flow three-way valve 15b, the third mixed flow three-way valve 15c, the first divided flow three-way valve 16a, the second divided flow three-way valve 16b, and the third divided flow three-way valve 16c are switched according to the operating state of the air conditioner 100.

<Indoor unit>
The first indoor unit 103a includes a first indoor heat exchanger 9a connected to the first mixed three-way valve 15a and the first split three-way valve 16a. The second indoor unit 103b includes a second indoor heat exchanger 9b connected to the second mixed three-way valve 15b and the second split three-way valve 16b. The third indoor unit 103c includes a third indoor heat exchanger 9c connected to the third mixed three-way valve 15c and the third split three-way valve 16c.

<Control device 200>
In the case of "operating state A", the control device 200 "opens" the first on-off valve 7a and "closes" the second on-off valve 7b. In the case of "operating state B", the control device 200 "closes" the first on-off valve 7a and "closes" the second on-off valve 7b. In the case of "operating state C", the control device 200 "closes" the first on-off valve 7a and "closes" the second on-off valve 7b. In the case of "operating state D", the control device 200 "closes" the first on-off valve 7a and "opens" the second on-off valve 7b.

In the case of "operating state A", the control device 200 switches the first relay four-way valve 13a so that the refrigerant flowing out of the first refrigerant-water heat exchanger 12a flows into the first check valve 6a and the refrigerant from the forward pipe t10 does not flow in. In the case of "operating state A", the control device 200 switches the second relay four-way valve 13b so that the refrigerant flowing out of the second refrigerant-water heat exchanger 12a flows into the first check valve 6a and the refrigerant from the forward pipe t10 does not flow.

In "operating state B" and "operating state C", the control device 200 switches the first relay four-way valve 13a so that the refrigerant from the forward pipe t10 flows into the first refrigerant-water heat exchanger 12a and the refrigerant flowing out of the second refrigerant-water heat exchanger 12b does not flow. In "operating state B", the control device 200 switches the second relay four-way valve 13b so that the refrigerant flowing out of the second indoor expansion valve 10b flows into the first check valve 6a and the refrigerant from the forward pipe t10 does not flow.

In "operating state D", the control device 200 switches the first relay four-way valve 13a so that the refrigerant from the forward pipe t10 flows into the first refrigerant-water heat exchanger 12a and the refrigerant from the return pipe t11 does not flow. In "operating state D", the controller 200 switches the second relay four-way valve 13b so that the refrigerant from the forward pipe t10 flows into the second refrigerant-water heat exchanger 12b and the refrigerant from the return pipe t11 does not flow.

<Operation of air conditioner 100 according to Modification 1>
The flow of water in the air conditioner 100 according to Modification 1 of Embodiment 1 will be described. The cold water or hot water generated by the first refrigerant-water heat exchanger 12a and the second refrigerant-water heat exchanger 12b is distributed to the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c, respectively, and is again sucked into the first pump 14a and the second pump 14b. Distribution of cold water or hot water to the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is performed by opening and closing the first mixed three-way valve 15a, the second mixed three-way valve 15b, the third mixed three-way valve 15c, the first divided three-way valve 16a, the second divided three-way valve 16b, and the third divided three-way valve 16c.

The refrigerant flow in the operating state A of the air conditioner 100 according to Modification 1 of Embodiment 1 will be described. 7 is a refrigerant circuit diagram and a water circuit diagram of the operating state A in the air conditioner 100 according to Modification 1 of Embodiment 1. FIG. The refrigerant flow in the outdoor unit 101 is the same as in FIG.

In operating state A, the main circuit and one bypass circuit are formed. In the main circuit, the refrigerant flows through the compressor 1, the first outdoor four-way valve 2a, the first outdoor heat exchanger 3a, the fifth check valve 6e, the subcooling heat exchanger 4, the fourth check valve 6d, the first on-off valve 7a, the first relay expansion valve 11a, the first refrigerant-water heat exchanger 12a, the first relay four-way valve 13a, the first check valve 6a, the first outdoor four-way valve 2a, and the compressor 1 again. In the main circuit, the refrigerant branched from between the first on-off valve 7a and the first relay expansion valve 11a flows through the second relay expansion valve 11b, the second refrigerant-water heat exchanger 12b, and the second relay four-way valve 13b in that order, and joins the refrigerant flowing out of the first relay four-way valve 13a.

In the bypass circuit, the refrigerant branched from between the supercooling heat exchanger 4 of the main circuit and the fourth check valve 6d flows through the second outdoor expansion valve 5b and the supercooling heat exchanger 4 in that order, and joins between the first outdoor four-way valve 2a of the main circuit and the suction side of the compressor 1.

The refrigerant flow in the operating state B of the air conditioner 100 according to Modification 1 of Embodiment 1 will be described. 8 is a refrigerant circuit diagram and a water circuit diagram of the operating state B in the air conditioner 100 according to Modification 1 of Embodiment 1. FIG. The refrigerant flow in the outdoor unit 101 is the same as in FIG.

In operating state B, the main circuit and one bypass circuit are formed. In the main circuit, the compressor 1, the first outdoor four-way valve 2a, the first outdoor heat exchanger 3a, the fifth check valve 6e, the subcooling heat exchanger 4, the fourth check valve 6d, the first relay four-way valve 13a, the first refrigerant-water heat exchanger 12a, the first relay expansion valve 11a, the second relay expansion valve 11b, the second refrigerant-water heat exchanger 12b, the second relay four-way valve 13b, the first check valve 6a, the second Refrigerant flows in the order of the one-outdoor four-way valve 2a and the compressor 1 again.

In the bypass circuit, the refrigerant branched from between the first outdoor heat exchanger 3a and the fifth check valve 6e of the main circuit flows to the first outdoor expansion valve 5a and joins between the subcooling heat exchanger 4 of the main circuit and the fourth check valve 6d.

The flow of the refrigerant in the operating state C in the air conditioner 100 according to Modification 1 of Embodiment 1 will be described. 9 is a refrigerant circuit diagram and a water circuit diagram of the operating state C in the air conditioner 100 according to Modification 1 of Embodiment 1. FIG. The refrigerant flow in the outdoor unit 101 is the same as in FIG.

In operating state C, the main circuit and one bypass circuit are formed. In the main circuit, the compressor 1, the first outdoor four-way valve 2a, the second check valve 6b, the first relay four-way valve 13a, the first refrigerant-water heat exchanger 12a, the first relay expansion valve 11a, the second relay expansion valve 11b, the second refrigerant-water heat exchanger 12b, the second relay four-way valve 13b, the third check valve 6c, the supercooling heat exchanger 4, the first outdoor expansion valve 5a, the first outdoor heat exchanger 3a, The refrigerant flows in order of the first outdoor four-way valve 2a and the compressor 1 again.

In the bypass circuit, the refrigerant branched from between the subcooling heat exchanger 4 of the main circuit and the first outdoor expansion valve 5a flows into the second outdoor expansion valve 5b and the subcooling heat exchanger 4, and the first outdoor four-way valve 2a of the main circuit joins between the compressor 1.

The flow of the refrigerant in the operating state D in the air conditioner 100 according to Modification 1 of Embodiment 1 will be described. 10 is a refrigerant circuit diagram and a water circuit diagram of the operating state D in the air conditioner 100 according to Modification 1 of Embodiment 1. FIG. The refrigerant flow in the outdoor unit 101 is the same as in FIG.

In operating state D, the main circuit and one bypass circuit are formed. In the main circuit, the refrigerant flows through the compressor 1, the first outdoor four-way valve 2a, the second check valve 6b, the first relay four-way valve 13a, the first refrigerant-water heat exchanger 12a, the first relay expansion valve 11a, the second on-off valve 7b, the third check valve 6c, the subcooling heat exchanger 4, the first outdoor expansion valve 5a, the first outdoor heat exchanger 3a, the first outdoor four-way valve 2a, and the compressor 1 again. In the main circuit, the refrigerant branched from between the second check valve 6b and the first relay four-way valve 13a flows through the second relay four-way valve 13b, the second refrigerant-water heat exchanger 12b, and the second relay expansion valve 11b in that order, and joins the refrigerant flowing out of the first relay four-way valve 13a.

In the bypass circuit, the refrigerant branched from between the subcooling heat exchanger 4 of the main circuit and the first outdoor expansion valve 5a flows into the second outdoor expansion valve 5b, and joins between the first outdoor four-way valve 2a of the main circuit and the compressor 1.

The subcooling heat exchanger 4 of the air conditioner 100 of Embodiment 1 exchanges heat between the refrigerant flowing in the pipe branching between the sixth point p6 and the fifth point p5 and connecting between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing through the fifth pipe t5. Note that the locations where the refrigerant branches may be between the third check valve 6c and the fifth check valve 6e and between the fourth check valve 6d and the first outdoor expansion valve 5a. In the air conditioner 100 of Embodiment 1, an outdoor unit 101 is equipped with five first check valves 6a, second check valves 6b, third check valves 6c, fourth check valves 6d, and fifth check valves 6e. According to the air conditioner 100 of Embodiment 1, counterflow of the refrigerant can be achieved in the subcooling heat exchanger 4 with five valves, so that the size of the housing of the outdoor unit 101 can be suppressed.

In addition, according to the air conditioner 100 of Embodiment 1, with five valves, it is possible to realize "counterflow of the supercooling heat exchanger 4 in both cooling and heating operations" and "a two-pipe system capable of simultaneous cooling and heating operation".

Embodiment 2.
Next, the air conditioner 100 according to Embodiment 2 will be described. FIG. 11 is a refrigerant circuit diagram of the air conditioner 100 according to Embodiment 2. As shown in FIG. The outdoor unit 101 of the air conditioner 100 according to Embodiment 2 includes, in addition to the air conditioner 100 shown in Embodiment 1, a second outdoor four-way valve 2b, a second outdoor heat exchanger 3b, a third outdoor expansion valve 5c, and a sixth check valve 6f. The sixth check valve 6f plays the role of the first outdoor expansion valve 5a in FIG. The configurations of the repeater 102, the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are the same as those shown in FIG. In FIG. 11, the same parts as in FIG. 1 are given the same reference numerals, and different parts will be explained.

<Outdoor unit 101>
As shown in FIG. 11, the sixth check valve 6f is provided in the first pipe t1 between the first point p1 and the fifth point p5. The sixth check valve 6f reduces the pressure of the refrigerant flowing from the fifth point p5 to the first point p1 during the heating operation, and is closed so that the refrigerant does not flow during the cooling operation.

The first outdoor expansion valve 5a is provided in the first pipe t1 between the first outdoor heat exchanger 3a and the first point p1.

The second outdoor four-way valve 2b is connected to the compressor 1 in parallel with the first outdoor four-way valve 2a. The second outdoor four-way valve 2b switches the flow direction of the refrigerant discharged from the compressor 1 and outputs the refrigerant, thereby switching between cooling and heating.

The second outdoor heat exchanger 3b exchanges heat between the refrigerant output from the second outdoor four-way valve 2b and the outside air. The third outdoor expansion valve 5c is provided in the first pipe t1 between the second outdoor heat exchanger 3b and the first point p1.

<Control device 200>
In "operating state A", the control device 200 switches the first outdoor four-way valve 2a and the second outdoor four-way valve 2b to the cooling side, opens the first outdoor expansion valve 5a and the third outdoor expansion valve 5c, opens the second outdoor expansion valve 5b, opens the first on-off valve 7a, and closes the second on-off valve 7b. When the operating state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is cooling operation, the control device 200 opens the first port, closes the second port, and opens the third port of the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c.

In the case of "operating state B", the control device 200 switches the first outdoor four-way valve 2a to the cooling side, opens the first outdoor expansion valve 5a, closes the second outdoor expansion valve 5b, closes the first on-off valve 7a, and closes the second on-off valve 7b. The control device 200 switches the second outdoor four-way valve 2b to the heating side and closes the third outdoor expansion valve 5c. When the state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is the operating state B, the control device 200 opens the first port, the second port, and the third port of the first three-way valve 8a of the first indoor unit 103a that is performing the heating operation. The first port of the second three-way valve 8b of the second indoor unit 103b that is performing cooling operation is opened, the second port is closed, and the third port is opened. The first port, the second port and the third port of the third three-way valve 8c of the third indoor unit 103c, which is in cooling operation, are opened.

In the case of "operating state C", the control device 200 switches the first outdoor four-way valve 2a to the heating side, opens the first outdoor expansion valve 5a, opens the second outdoor expansion valve 5b, closes the first on-off valve 7a, and opens the second on-off valve 7b. The control device 200 switches the second outdoor four-way valve 2b to the heating side and opens the third outdoor expansion valve 5c. When the state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is the operating state C, the control device 200 opens the first port, the second port, and the third port of the first three-way valve 8a of the first indoor unit 103a that is performing the heating operation. The first port, the second port, and the third port of the second three-way valve 8b of the second indoor unit 103b that is performing the heating operation are opened. The first port, the second port and the third port of the third three-way valve 8c of the third indoor unit 103c, which is in cooling operation, are opened.

In the case of "operating state D", the control device 200 switches the first outdoor four-way valve 2a and the second outdoor four-way valve 2b to the heating side, opens the first outdoor expansion valve 5a and the third outdoor expansion valve 5c, opens the second outdoor expansion valve 5b, closes the first on-off valve 7a, and closes the second on-off valve 7b. When the operating state of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c is heating operation, the control device 200 opens the first port, the second port, and the third port of the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c.

<Operation of air conditioner 100>
The operation of the air conditioner 100 of Embodiment 2 will be described. FIG. 12 is a refrigerant circuit diagram showing the flow of refrigerant in operating state A in the air conditioner 100 according to Embodiment 2. As shown in FIG. FIG. 13 is a refrigerant circuit diagram showing the flow of refrigerant in operating state B in the air conditioner 100 according to Embodiment 2. As shown in FIG. FIG. 14 is a refrigerant circuit diagram showing the flow of refrigerant in operating state C in the air conditioner 100 according to Embodiment 2. As shown in FIG. FIG. 15 is a refrigerant circuit diagram showing the flow of refrigerant in operating state D in the air conditioner 100 according to Embodiment 2. As shown in FIG. 12, 13, 14 and 15, the arrows indicate the direction of coolant flow. The configurations of the repeater 102, the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are the same as those shown in FIG. 12, 13, 14 and 15, the same parts as in FIG. 1 are given the same reference numerals, and different parts will be explained.

(Operating state A: full cooling operation)
FIG. 12 shows a state in which all of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are performing cooling operation.

In operating state A, the main circuit and four bypass circuits are formed. As shown in FIG. 12, in the main circuit, the compressor 1, the first outdoor four-way valve 2a, the first outdoor heat exchanger 3a, the first outdoor expansion valve 5a, the fifth check valve 6e, the subcooling heat exchanger 4, the fourth check valve 6d, the first on-off valve 7a, the first indoor expansion valve 10a, the first indoor heat exchanger 9a, the first three-way valve 8a, the first check valve 6a, the first outdoor four-way valve 2a, the compressor again. The refrigerant flows in the order of 1.

In the first bypass circuit, the refrigerant branched from between the compressor 1 of the main circuit and the first outdoor four-way valve 2a flows through the second outdoor four-way valve 2b, the second outdoor heat exchanger 3b, and the third outdoor expansion valve 5c in that order, and joins between the first outdoor expansion valve 5a and the fifth check valve 6e of the main circuit. In the second bypass circuit, the refrigerant branched from between the supercooling heat exchanger 4 of the main circuit and the fourth check valve 6d flows in the order of the second outdoor expansion valve 5b and the supercooling heat exchanger 4, and joins between the first outdoor four-way valve 2a of the main circuit and the suction side of the compressor 1. In the third bypass circuit, the refrigerant branched from between the first on-off valve 7a and the first indoor expansion valve 10a of the main circuit flows through the second indoor expansion valve 10b, the second indoor heat exchanger 9b, and the second three-way valve 8b in that order, and joins between the first three-way valve 8a and the first check valve 6a of the main circuit. In the fourth bypass circuit, the refrigerant branched from between the first on-off valve 7a and the first indoor expansion valve 10a of the main circuit flows in the order of the third indoor expansion valve 10c, the third indoor heat exchanger 9c, and the third three-way valve 8c, and joins between the first three-way valve 8a and the first check valve 6a of the main circuit.

(Operating state B: cooling and heating mixed operation, cooling load > heating load)
FIG. 13 shows a state in which the first indoor unit 103a is in heating operation, and the second indoor unit 103b and third indoor unit 103c are in cooling operation.

In operating state B, the main circuit and one bypass circuit are formed. In the main circuit, as shown in FIG. 13, the compressor 1, the first outdoor four-way valve 2a, the first outdoor heat exchanger 3a, the first outdoor expansion valve 5a, the fifth check valve 6e, the subcooling heat exchanger 4, the fourth check valve 6d, the first three-way valve 8a, the first indoor heat exchanger 9a, the first indoor expansion valve 10a, the second indoor expansion valve 10b, the second indoor heat exchanger 9b, the second three-way valve 8b, the first Refrigerant flows through the check valve 6a, the first outdoor four-way valve 2a, and the compressor 1 again.

In the bypass circuit, the refrigerant branched from between the first indoor expansion valve 10a and the second indoor expansion valve 10b of the main circuit flows through the third indoor expansion valve 10c, the third indoor heat exchanger 9c, and the third three-way valve 8c in that order, and joins between the second three-way valve 8b and the first check valve 6a of the main circuit.

(Operating state C: cooling and heating mixed operation, heating load > cooling load)
FIG. 14 shows a state in which the first indoor unit 103a and the second indoor unit 103b are in heating operation, and the third indoor unit 103c is in cooling operation.

In operating state C, the main circuit and three bypass circuits are formed. In the main circuit, as shown in FIG. 14, the compressor 1, the first outdoor four-way valve 2a, the second check valve 6b, the first three-way valve 8a, the first indoor heat exchanger 9a, the first indoor expansion valve 10a, the third indoor expansion valve 10c, the third indoor heat exchanger 9c, the third three-way valve 8c, the third check valve 6c, the subcooling heat exchanger 4, the first outdoor expansion valve 5a, the first outdoor heat exchanger 3a, the first The refrigerant flows in the order of the outdoor four-way valve 2a and the compressor 1 again.

In the first bypass circuit, the refrigerant branched from between the second check valve 6b and the first three-way valve 8a of the main circuit flows through the second three-way valve 8b, the second indoor heat exchanger 9b, and the second indoor expansion valve 10b in that order, and joins between the first indoor expansion valve 10a and the third indoor expansion valve 10c of the main circuit. In the second bypass circuit, the refrigerant branched from between the supercooling heat exchanger 4 of the main circuit and the first outdoor expansion valve 5a flows into the second outdoor expansion valve 5b and the supercooling heat exchanger 4, and joins between the first outdoor four-way valve 2a and the compressor 1 of the main circuit. In the third bypass circuit, the refrigerant branched from between the sixth check valve 6f and the first outdoor expansion valve 5a of the main circuit flows into the third outdoor expansion valve 5c, the second outdoor expansion valve 5b, and the second outdoor four-way valve 2b, and joins between the first outdoor four-way valve 2a of the main circuit and the compressor 1.

(Operating state D: All heating operation)
FIG. 15 shows a state in which all of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are performing heating operation.

In operating state D, the main circuit and four bypass circuits are formed. In the main circuit, as shown in the main circuit, as shown in FIG. 15, the compression machine 1, the first outdoor four -sided valve, the second reverse valve 6B, the first three -sided dialect 8a, the first indoor heat exchanger 9a, the first indoor expansion valve 10a, the second opening and closing valve 6c, the third reverse valve 6c, the supercooled heat exchanger 4, the first outdoor expansion valve 5a, the first outrage. The refrigerant flows in the order of outdoor heat exchangers, 2A, 1st outdoor four -sided valve, and compressor 1 again.

In the first bypass circuit, the refrigerant branched from between the second check valve 6b and the first three-way valve 8a of the main circuit flows through the second three-way valve 8b, the second indoor heat exchanger 9b, and the second indoor expansion valve 10b in that order, and joins between the first indoor expansion valve 10a and the second on-off valve 7b of the main circuit. In the second bypass circuit, the refrigerant branched from between the second check valve 6b and the first three-way valve 8a of the main circuit flows through the third three-way valve 8c, the third indoor heat exchanger 9c, and the third indoor expansion valve 10c in that order, and joins between the first indoor expansion valve 10a and the second on-off valve 7b of the main circuit. In the third bypass circuit, the refrigerant branched from between the supercooling heat exchanger 4 and the first outdoor expansion valve 5a of the main circuit flows to the second outdoor expansion valve 5b and the supercooling heat exchanger 4, and joins between the first outdoor four-way valve 2a and the compressor 1 of the main circuit. In the fourth bypass circuit, the refrigerant branched from between the sixth check valve 6f and the first outdoor expansion valve 5a of the main circuit flows into the third outdoor expansion valve 5c, the second outdoor heat exchanger 3b, and the second outdoor four-way valve 2b, and joins between the first outdoor four-way valve 2a of the main circuit and the compressor 1.

<Modification 1>
In Modification 1 of Embodiment 2, two types of heat media, refrigerant and water, form circuits independently without being mixed, and heat is only exchanged through the first refrigerant-water heat exchanger 12a and the second refrigerant-water heat exchanger 12b. Refrigerant-water heat exchangers include, for example, plate heat exchangers and shell-and-tube heat exchangers.

FIG. 16 is a refrigerant circuit diagram and a water circuit diagram of an air conditioner 100 according to Modification 1 of Embodiment 2. FIG. The same parts as those in FIG. 11 are denoted by the same reference numerals, and the description thereof is omitted. In Modification 1 of Embodiment 2, the configurations of the repeater 102, the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c in the air conditioner 100 of Embodiment 2 are different.

The configurations of the repeater 102, the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are the same as the configurations of the repeater 102, the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c of Modification 1 of Embodiment 1 shown in FIG.

<Control device 200>
In "operating state A", the control device 200 switches the first outdoor four-way valve 2a and the second outdoor four-way valve 2b to the cooling side, opens the first outdoor expansion valve 5a and the third outdoor expansion valve 5c, opens the second outdoor expansion valve 5b, opens the first on-off valve 7a, and closes the second on-off valve 7b. The control device 200 switches the first relay four-way valve 13a so that the refrigerant flowing out of the first refrigerant-water heat exchanger 12a flows into the first check valve 6a and the refrigerant from the forward pipe t10 does not flow in in the case of "operating state A". In the case of "operating state A", the control device 200 switches the second relay four-way valve 13b so that the refrigerant flowing out of the second refrigerant-water heat exchanger 12a flows into the first check valve 6a and the refrigerant from the forward pipe t10 does not flow.

In the case of "operating state B", the control device 200 switches the first outdoor four-way valve 2a to the cooling side, opens the first outdoor expansion valve 5a, closes the second outdoor expansion valve 5b, closes the first on-off valve 7a, and closes the second on-off valve 7b. The control device 200 switches the second outdoor four-way valve 2b to the heating side and closes the third outdoor expansion valve 5c.

In the case of "operating state C", the control device 200 switches the first outdoor four-way valve 2a to the heating side, opens the first outdoor expansion valve 5a, opens the second outdoor expansion valve 5b, closes the first on-off valve 7a, and opens the second on-off valve 7b. The control device 200 switches the second outdoor four-way valve 2b to the heating side and opens the third outdoor expansion valve 5c.

In the case of "operating state D", the control device 200 switches the first outdoor four-way valve 2a and the second outdoor four-way valve 2b to the heating side, opens the first outdoor expansion valve 5a and the third outdoor expansion valve 5c, opens the second outdoor expansion valve 5b, closes the first on-off valve 7a, and closes the second on-off valve 7b. In "operating state D", the controller 200 switches the first relay four-way valve 13a so that the refrigerant from the forward pipe t10 flows into the first refrigerant-water heat exchanger 12a and the refrigerant from the return pipe t11 does not flow. In "operating state D", the controller 200 switches the second relay four-way valve 13b so that the refrigerant from the forward pipe t10 flows into the second refrigerant-water heat exchanger 12b and the refrigerant from the return pipe t11 does not flow.

<Operation of air conditioner 100 according to Modification 1>
17 is a refrigerant circuit diagram and a water circuit diagram of the operating state A in the air conditioner 100 according to Modification 1 of Embodiment 2. FIG. 18 is a refrigerant circuit diagram and a water circuit diagram of the operating state B in the air conditioner 100 according to Modification 1 of Embodiment 2. FIG. 19 is a refrigerant circuit diagram and a water circuit diagram of the operating state C in the air conditioner 100 according to Modification 1 of Embodiment 2. FIG. 20 is a refrigerant circuit diagram and a water circuit diagram of the operating state D in the air conditioner 100 according to Modification 1 of Embodiment 2. FIG.

The operation of the outdoor unit 101 in the operating state A, the operating state B, the operating state C, and the operating state D of the outdoor unit 101 in the air conditioner 100 according to the modified example 1 of the second embodiment is the same as the operation in the operating state A, the operating state B, the operating state C, and the operating state D of the outdoor unit 101 in the air conditioner 100 described in the second embodiment.

The operations of the repeater 102 in the operating state A, the operating state B, the operating state C, and the operating state D of the air conditioner 100 according to Modification 1 of Embodiment 2 are the same as those of the repeater 102 in the air conditioner 100 described in Modification 1 of Embodiment 1.

The operations of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c in the air conditioner 100 according to Modification 1 of Embodiment 2 in the operation state A, the operation state B, the operation state C, and the operation state D are the same as the operations of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c in the air conditioner 100 described in Modification 1 of Embodiment 1.

The subcooling heat exchanger 4 of the air conditioner 100 of Embodiment 2 exchanges heat between the refrigerant flowing in the pipe branching between the sixth point p6 and the fifth point p5 and connecting between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing through the fifth pipe t5. Note that the locations where the refrigerant branches may be between the third check valve 6c and the fifth check valve 6e and between the fourth check valve 6d and the first outdoor expansion valve 5a. In the air conditioner 100 of Embodiment 2, the outdoor unit 101 is equipped with six first check valves 6a, second check valves 6b, third check valves 6c, fourth check valves 6d, fifth check valves 6e and sixth check valves 6f. According to the air-conditioning apparatus 100 of Embodiment 2, the counterflow of the refrigerant can be achieved in the subcooling heat exchanger 4 with six valves, so that the size of the housing of the outdoor unit 101 can be suppressed.

In addition, according to the air conditioner 100 of Embodiment 2, with six valves, it is possible to realize "counterflow of the supercooling heat exchanger 4 in both cooling and heating operations" and "a two-pipe system capable of simultaneous cooling and heating operation".

In Embodiments 1 and 2, the forward pipe t10 is also called the first pipe, the return pipe t11 is also called the second pipe, the first outdoor four-way valve 2a is also called the first switching valve, and the second outdoor four-way valve 2b is also called the second switching valve. The subcooling heat exchangers 4 of Embodiments 1 and 2 are also referred to as refrigerant heat exchangers. The first check valve 6a, the second check valve 6b, the third check valve 6c, the fourth check valve 6d, the fifth check valve 6e, and the sixth check valve 6f are also referred to as the first valve, the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve, respectively. The first outdoor expansion valve 5a is also called a sixth valve.

Embodiments 1 and 2 are presented as examples and are not intended to limit the scope of claims. Embodiments 1 and 2 can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of Embodiments 1 and 2.

1 compressor, 2a first outdoor four-way valve, 2b second outdoor four-way valve, 3a first outdoor heat exchanger, 3b second outdoor heat exchanger, 4 subcooling heat exchanger, 5a first outdoor expansion valve, 5b second outdoor expansion valve, 5c third outdoor expansion valve, 6a first check valve, 6b second check valve, 6c third check valve, 6d fourth check valve Stop valve 6e Fifth check valve 6f Sixth check valve 7a First on-off valve 7b Second on-off valve 8a First three-way valve 8b Second three-way valve 8c Third three-way valve 9a First indoor heat exchanger 9b Second indoor heat exchanger 9c Third indoor heat exchanger 10a First indoor expansion valve 10b Second indoor expansion valve 10c Third indoor expansion valve 11a first relay expansion valve, 11b second relay expansion valve, 12a first refrigerant-water heat exchanger, 12b second refrigerant-water heat exchanger, 13a first relay four-way valve, 13b second relay four-way valve, 14a first pump, 14b second pump, 15a first mixed three-way valve, 15b second mixed three-way valve, 15c third mixed three-way valve, 16 a 1st branch three-way valve, 16b 2nd branch 3-way valve, 16c 3rd branch 3-way valve, 100 air conditioner, 101 outdoor unit, 102 repeater, 103 indoor unit, 103a first indoor unit, 103b second indoor unit, 103c third indoor unit, 200 control device, p1 first point, p2 second point, p3 third point, p 4 4th point, p5 5th point, p6 6th point, p7 7th point, t1 1st pipe, t2 2nd pipe, t3 3rd pipe, t4 4th pipe, t5 5th pipe, t6 6th pipe, t10 forward pipe, t11 return pipe, t12a, t12b, t12c, t13a, t13b, t13c pipe, r rectifier circuit, A, B , C, D Operation status.

Claims

an outdoor unit comprising a compressor, a first switching valve, a first outdoor heat exchanger and a first outdoor expansion valve;
an indoor unit for cooling or heating the room;
a first pipe through which a refrigerant flowing out of the outdoor unit and flowing into the indoor unit flows;
a second pipe through which the refrigerant flows out from the indoor unit and flows into the outdoor unit;
The outdoor unit is
a rectifying circuit that determines a flow direction of the refrigerant flowing out of the outdoor unit to the first pipe and a flow direction of the refrigerant flowing into the outdoor unit through the second pipe;
a refrigerant heat exchanger that cools the refrigerant flowing into the suction side of the compressor with the refrigerant diverted from the refrigerant flowing to the rectifier circuit;
a first pipe connecting the first outdoor heat exchanger and the first pipe;
a second pipe connecting the second pipe and the first switching valve;
Of the two points in the middle of the first pipe, the first point and the second point from the side closer to the first outdoor heat exchanger, and the third point and the fourth point from the side closer to the second pipe out of the two points in the middle of the second pipe,
a third pipe connecting the first point and the third point;
A fourth pipe connecting the second point and the fourth point,
The rectifier circuit is
a first valve provided in the second pipe for allowing the refrigerant in the second pipe to flow from the third point to the fourth point and preventing reverse flow;
a second valve provided in the fourth pipe for allowing the refrigerant in the fourth pipe to flow from the fourth point to the second point and preventing reverse flow;
a third valve provided in the third pipe for allowing the refrigerant in the third pipe to flow from the third point to the first point and preventing reverse flow;
a fourth valve provided in the first pipe to allow the refrigerant in the first pipe to flow from the first point to the second point and prevent it from flowing in the opposite direction;
The outdoor unit is
a fifth valve provided in the third pipe that allows the refrigerant in the third pipe to flow from the first point to a sixth point between the first point and the third valve and prevents reverse flow;
a sixth valve provided in the first pipe, capable of allowing the refrigerant in the first pipe to flow from a fifth point between the first point and the fourth valve to the first point and preventing reverse flow;
a fifth pipe connecting the fifth point and the sixth point, through which the refrigerant flows from the sixth point to the fifth point;
The heat exchanger between refrigerants,
The first switching valve branching from any point between the third valve and the fifth valve, between the fourth valve and the sixth valve, and between the sixth point and the fifth point An air conditioner that exchanges heat between the refrigerant flowing in a pipe connected between the first switching valve and the suction side of the compressor and the refrigerant flowing in the fifth pipe.
2. The air conditioner according to claim 1, further comprising a second outdoor expansion valve that reduces pressure of the refrigerant branched from between the sixth point and the fifth point.
3. The air conditioner according to claim 2, wherein the sixth valve reduces the pressure of the refrigerant flowing from the fifth point to the first point during heating and is closed so that the refrigerant does not flow during cooling.
The sixth valve is a check valve,
The air conditioner according to claim 2 or 3, wherein the first outdoor expansion valve is provided in the first pipe between the first outdoor heat exchanger and the first point.
a second switching valve connected to the compressor in parallel with the first switching valve, switching a flow direction of the refrigerant discharged from the compressor, and switching between the cooling and the heating;
a second outdoor heat exchanger in which heat exchange of the refrigerant output from the second switching valve is performed;
5. The air conditioner according to claim 4, further comprising a third outdoor expansion valve provided in said first pipe between said second outdoor heat exchanger and said first point.
Having a plurality of indoor units,
a control device that simultaneously performs the cooling and the heating of the plurality of indoor units,
The control device is
When all of the plurality of indoor units perform cooling,
a first main circuit in which the refrigerant flows in the order of the first valve, the first switching valve, the compressor, the first switching valve, the first outdoor heat exchanger, the first outdoor expansion valve, the fifth valve, the heat exchanger between refrigerants, and the fourth valve;
a first bypass flow path branched from between the refrigerant heat exchanger and the fourth valve of the first main circuit, the refrigerant flows through the second outdoor expansion valve and the refrigerant heat exchanger in this order, and joins between the first switching valve of the first main circuit and the suction side of the compressor;
A second bypass flow path branched from between the compressor of the first main circuit and the first switching valve, the refrigerant flows in the order of the second switching valve, the second outdoor heat exchanger, and the third outdoor expansion valve, and joins between the first outdoor expansion valve and the fifth valve of the first main circuit, is formed in the outdoor unit;
When the indoor unit that performs the cooling and the indoor unit that performs the heating are mixed, and the cooling load of the plurality of indoor units is larger than the heating load of the plurality of indoor units,
The first main circuit is formed in the outdoor unit,
When the indoor unit performing the cooling and the indoor unit performing the heating are mixed, and the heating load of the plurality of indoor units is larger than the cooling load of the plurality of indoor units, or when all of the plurality of indoor units perform the heating,
a second main circuit in which the refrigerant flows in the order of the third valve, the heat exchanger between refrigerants, the sixth valve, the first outdoor expansion valve, the first outdoor heat exchanger, the first switching valve, the compressor, the first switching valve, and the second valve;
a third bypass flow path branched from between the refrigerant heat exchanger and the first outdoor expansion valve of the second main circuit, the refrigerant flows in the order of the second outdoor expansion valve and the refrigerant heat exchanger, and joins between the first switching valve of the second main circuit and the suction side of the compressor;
The air conditioner according to claim 5, wherein operation is controlled such that a fourth bypass flow path is formed in the outdoor unit, in which the refrigerant branches from between the sixth valve of the second main circuit and the heat exchanger between refrigerants, flows through the second outdoor expansion valve and the heat exchanger between refrigerants in that order, and merges between the first switching valve of the second main circuit and the suction side of the compressor.