JP7580640B2 - Air Conditioning Equipment - Google Patents

Description

The present disclosure relates to a two-pipe air conditioning system in which the outdoor unit has a refrigerant heat exchanger.

There is an air conditioner that has a refrigerant-to-refrigerant heat exchanger, and the outdoor unit and the relay unit are connected by two connecting pipes (see, for example, Patent Document 1). In the air conditioner described in Patent Document 1, the four check valves in the outdoor unit unify the outgoing pipe and return pipe connecting the outdoor unit and the relay unit in all operating modes, making it possible to perform simultaneous cooling and heating operations with a two-pipe system. In addition, in the air conditioner described in Patent Document 1, in cooling operation, the high-pressure refrigerant and the low-pressure refrigerant in the subcooling heat exchanger, which is a refrigerant-to-refrigerant heat exchanger, flow in counterflow. In addition, in heating operation, the high-pressure refrigerant and the low-pressure refrigerant in the subcooling heat exchanger flow in parallel.

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

In a two-pipe air conditioning system, in order to achieve "counter-flow refrigerant heat exchanger in both cooling and heating operation," four valves are required, as shown in JP 2003-075026 A, for example.

Therefore, to achieve both "counter-flow refrigerant heat exchanger for both cooling and heating operation" and "two-pipe air conditioner" by combining conventional technologies, four valves of each type are required, for a total of eight valves. However, there was a problem that installing eight valves to achieve both of these would result in the outdoor unit housing becoming larger.

The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a two-pipe air conditioning system equipped with an outdoor unit having a refrigerant heat exchanger that can suppress an increase in size of the outdoor unit casing and allows counter-flow between the refrigerants during both cooling and heating operation.

The air-conditioning apparatus according to the present disclosure comprises an outdoor unit having a compressor, a first switching valve, a first outdoor heat exchanger, and a first outdoor expansion valve, an indoor unit for cooling or heating a room, a first pipe through which a refrigerant flows out of the outdoor unit and into the indoor unit, and a second pipe through which the refrigerant flows out of the indoor unit and into the outdoor unit, and the outdoor unit comprises a rectifying circuit that determines the flow direction of the refrigerant flowing out of the outdoor unit into the first pipe and the flow direction of the refrigerant flowing into the outdoor unit via the second pipe, a refrigerant-to-refrigerant heat exchanger that cools the refrigerant flowing into the suction side of the compressor with the refrigerant diverted from the refrigerant flowing into the rectifying circuit, and a first refrigerant-to-refrigerant heat exchanger that diverges from the refrigerant flowing into the rectifying circuit and a second ... the first pipe connecting the outdoor heat exchanger and the first pipe, the second pipe connecting the second pipe and the first switching valve, and, when two points in the first pipe are defined as a first point and a second point from a side closer to the first outdoor heat exchanger, and two points in the second pipe are defined as a third point and a fourth point from a side closer to the second pipe, a third pipe connecting the first point and the third point, and a fourth pipe connecting the second point and the fourth point, the rectifying circuit being provided in the second pipe and including a first valve that allows the refrigerant in the second pipe to flow from the third point to the fourth point and prevents the refrigerant from flowing in the reverse direction, and a fourth valve that is provided in the fourth pipe and includes the a second valve that allows the refrigerant in the fourth pipe to flow from the fourth point to the second point and prevents the refrigerant from flowing in the reverse direction, a third valve that is provided in the third pipe and allows the refrigerant in the third pipe to flow from the third point to the first point and prevents the refrigerant from flowing in the reverse direction, and a fourth valve that is provided in the first pipe and allows the refrigerant in the first pipe to flow from the first point to the second point and prevents the refrigerant from flowing in the reverse direction, and the outdoor unit is provided with a fifth valve that is provided in the third pipe and 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 refrigerant from flowing in the reverse direction. a sixth valve provided in the first piping, allowing the refrigerant in the first piping to flow from a fifth point between the first point and the fourth valve to the first point and preventing the refrigerant from flowing in the reverse direction; and a fifth piping connecting the fifth point and the sixth point and through which the refrigerant flows from the sixth point to the fifth point, wherein the refrigerant-to-refrigerant heat exchanger exchanges heat between the refrigerant flowing in the fifth piping, and the refrigerant flowing in the fifth piping, which branches off from any one of a point between the third valve and the fifth valve, a point between the fourth valve and the sixth valve, and a point between the sixth point and the fifth point and connects between the first switching valve and a suction side of the compressor.

In the air conditioning apparatus of the present disclosure, the refrigerant-to-refrigerant heat exchanger exchanges heat between 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 connects between the first switching valve and the suction side of the compressor, and the refrigerant flowing in the fifth pipe. According to the air conditioning apparatus of the present disclosure, the six valves, the first valve, the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve, can counter-flow the refrigerant in the medium-to-medium heat exchanger, thereby preventing the outdoor unit housing from becoming large.

1 is a refrigerant circuit diagram of an air conditioning apparatus according to a first embodiment. FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state A in the air conditioning apparatus according to the first embodiment. FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state B in the air conditioning apparatus according to the first embodiment. FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state C in the air conditioning apparatus according to the first embodiment. FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state D in the air conditioning apparatus according to the first embodiment. FIG. FIG. 4 is a refrigerant circuit diagram and a water circuit diagram of an air conditioning apparatus according to a first modified example of the first embodiment. FIG. 4 is a refrigerant circuit diagram and a water circuit diagram in an operating state A of an air conditioning apparatus according to a first modified example of the first embodiment. FIG. 11 is a refrigerant circuit diagram and a water circuit diagram in an operating state B of an air conditioning apparatus according to a first modified example of the first embodiment. FIG. 11 is a refrigerant circuit diagram and a water circuit diagram in an operating state C of an air conditioning apparatus according to a first modified example of the first embodiment. FIG. 11 is a refrigerant circuit diagram and a water circuit diagram in an operating state D of an air conditioning apparatus according to a first modified example of the first embodiment. FIG. 6 is a refrigerant circuit diagram of an air conditioning apparatus according to a second embodiment. FIG. 11 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state A in an air conditioning apparatus according to a second embodiment. FIG. 11 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state B in an air conditioning apparatus according to embodiment 2. FIG. 11 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state C in an air conditioning apparatus according to embodiment 2. FIG. 11 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state D in an air conditioning apparatus according to embodiment 2. FIG. 11 is a refrigerant circuit diagram and a water circuit diagram of an air conditioning apparatus according to a first modified example of the second embodiment. FIG. 11 is a refrigerant circuit diagram and a water circuit diagram in an air conditioning apparatus according to a first modified example of the second embodiment in an operating state A. FIG. 11 is a refrigerant circuit diagram and a water circuit diagram in an operating state B of an air conditioning apparatus according to a first modified example of the second embodiment. FIG. 13 is a refrigerant circuit diagram and a water circuit diagram in an operating state C of an air conditioning apparatus according to a first modified example of the second embodiment. FIG. 13 is a refrigerant circuit diagram and a water circuit diagram in an air conditioning apparatus according to a first modified example of the second embodiment in an operating state D.

Below, an air conditioning device according to an embodiment will be described with reference to the drawings. In the drawings, identical components will be denoted with the same reference numerals and will be described only when necessary. This disclosure may include any combination of possible configurations among those described in the following embodiments. The forms of the components shown in the entire specification are merely examples and are not limited to the forms described in the specification. In particular, the combinations of the components are not limited to only those in each embodiment, and components described in other embodiments may be applied to other embodiments.

Embodiment 1.
<Configuration of the air conditioning device 100>
Fig. 1 is a refrigerant circuit diagram of an air-conditioning apparatus 100 according to embodiment 1. As shown in Fig. 1, the air-conditioning apparatus 100 has an outdoor unit 101, a relay unit 102, a first indoor unit 103a, a second indoor unit 103b, and a third indoor unit 103c. The outdoor unit 101 and the relay unit 102 are connected by two pipes, a supply pipe t10 and a return pipe t11.

The outgoing pipe t10 is used for refrigerant that flows out from the outdoor unit 101 and flows into the repeater unit 102. The refrigerant that flows into the repeater unit 102 flows out from the repeater unit 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. The return pipe t11 is used for refrigerant that flows out from the first indoor unit 101a, the second indoor unit 103b, and the third indoor unit 103c and flows into the outdoor unit 101 via the repeater unit 102.

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

<Outdoor unit 101>
The outdoor unit 101 is equipped with 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, a "check valve" is a valve that has a valve that closes depending on the pressure difference between before and after the valve, and allows water to flow only from the side with higher pressure to the side with lower pressure.

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 it, 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 flow path switching device that switches the flow direction of the refrigerant. The refrigerant flow path switching device may be configured with a combination of two-way valves or three-way valves. Furthermore, if the air conditioning device 100 is dedicated to cooling or heating and there is no need to switch the flow direction of the refrigerant, there is no need to provide a refrigerant flow path switching device.

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 rectifying circuit r determines the flow direction of the refrigerant flowing out from the outdoor unit 101 to the outflow pipe t10 and the flow direction of the refrigerant flowing into the outdoor unit 101 via 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 outgoing pipe t10. The second pipe t2 connects the return pipe t11 and the first outdoor four-way valve 2a. Of the two points in the first pipe t1, the first point p1 and the second point p2 are the points closer to the first outdoor heat exchanger 3a, and of the two points in the second pipe t2, the third point p3 and the fourth point p4 are the points 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 in 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 in 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. The sixth pipe t6 branches off from the fifth pipe t5 and is connected between the first outdoor four-way valve 2a and the suction side of the compressor 1.

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

The subcooling heat exchanger 4 cools the refrigerant flowing into the suction side of the compressor 1 with refrigerant diverted from the refrigerant flowing into the rectifier circuit r. The subcooling heat exchanger 4 exchanges heat between the refrigerant flowing in the sixth pipe t6 that branches off between the sixth point p6 and the fifth point p5 and connects between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing in the fifth pipe t5 from the sixth point p6 to the fifth point p5. The subcooling heat exchanger 4 may also exchange heat between the refrigerant flowing in a pipe (not shown) that branches off between the third check valve 6c and the fifth check valve 6e and connects between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing in the fifth pipe t5 from the sixth point p6 to the fifth point p5. The subcooling heat exchanger 4 may exchange heat between the refrigerant flowing through a pipe (not shown) that branches off between the fourth check valve 6d and the first outdoor expansion valve 5a and connects 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 from the sixth point p6 to the fifth point p5.

In embodiment 1, a fifth check valve 6e is added to the rectification circuit r, and a first outdoor expansion valve 5a is utilized to counter-flow the refrigerant flowing through the subcooling heat exchanger 4 during cooling and heating.

The first check valve 6a of the rectifier circuit r is provided in the second pipe t2 and 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 and allows the refrigerant in the fourth pipe t4 to flow from the fourth point p4 to the second point p2 and prevents it from flowing in the opposite direction. The third check valve 6c is provided in the third pipe t3 and allows the refrigerant in the third pipe t3 to flow from the third point p3 to the first point p1 and prevents it from flowing in the opposite direction. The fourth check valve 6d is provided in the first pipe t1 and allows the refrigerant in the first pipe t1 to flow from the first point p1 to the second point p2 and prevents it 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, but prevents it from flowing in the reverse 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 allows the refrigerant in the first pipe t1 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 prevent the refrigerant from flowing in the opposite direction. It allows the refrigerant to flow from point p5 to the first point p1, and can prevent the refrigerant from flowing in the opposite direction. The first outdoor expansion valve 5a in this embodiment allows the refrigerant to flow from the fifth point p5 between the first point p1 and the fourth check valve 6d to the first point p1, and prevents the refrigerant from flowing in the opposite direction, due to the pressure difference before and after the first outdoor expansion valve 5a in a specific operating state (operating state B described later).

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 to prevent refrigerant from flowing during cooling operation.

The second outdoor expansion valve 5b is provided in the sixth pipe t6 and allows 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 prevents the refrigerant from flowing in the reverse direction. The second outdoor expansion valve 5b adjusts the pressure of the refrigerant flowing through the sixth pipe t6.

<Repeater 102>
The relay unit 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 of the refrigerant flowing through the outflow pipe t10 until it 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, depending on the operating state.

The first three-way valve 8a has a first port connected to the first indoor heat exchanger 9a, a second port connected to the supply 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 supply 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 supply 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 outgoing pipe t10 is connected to the piping connected 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 the piping 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 piping 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 piping t12a. The second indoor heat exchanger 9b is connected to the first port of the second three-way valve 8b by piping 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 piping t12a and piping t12b. The third indoor heat exchanger 9c is connected to the first port of the third three-way valve 8c by piping 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 piping t12a and piping t12c.

<Control device 200>
The control device 200 controls the compressor 1, 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 of the outdoor unit 101 depending on the operating state of the air conditioning apparatus 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 relay unit 102 depending on the operating state of the air conditioning unit 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 depending on the operating state of the air conditioning unit 100.

Among the operating states, "operating state A" is an operating state in which all of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are operating in cooling mode. "Operating state B" is an operating state in which some of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are operating in cooling mode, and some or all of the other units are operating in heating mode. Furthermore, "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. "Operating state C" is an operating state in which some of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are operating in cooling mode, and some or all of the other units are operating in heating mode. Furthermore, "operation state C" is an operation state in which the heating operation 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. "Operation state D" is an operation state in which the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are all performing 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 opening/closing valve 7a, and closes the second opening/closing valve 7b. When the operating states of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are 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 "operation 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 opening/closing valve 7a, and closes the second opening/closing valve 7b. When the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are in operation state B, the control device 200 opens the first port, opens the second port, and opens the third port of the first three-way valve 8a of the first indoor unit 103a performing heating operation. Opens the first port, closes the second port, and opens the third port of the second three-way valve 8b of the second indoor unit 103b performing cooling operation. Opens the first port, closes the second port, and opens the third port of the third three-way valve 8c of the third indoor unit 103c performing cooling operation.

In the case of "operation 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 opening/closing valve 7a, and opens the second opening/closing valve 7b. When the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are in operation state C, the control device 200 opens the first port, opens the second port, and opens the third port of the first three-way valve 8a of the first indoor unit 103a performing heating operation. The control device 200 opens the first port, opens the second port, and opens the third port of the second three-way valve 8b of the second indoor unit 103b performing heating operation. The control device 200 opens the first port, closes the second port, and opens the third port of the third three-way valve 8c of the third indoor unit 103c performing cooling operation.

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 opening/closing valve 7a, and closes the second opening/closing valve 7b. When the operating states of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are in heating operation, the control device 200 opens the first port, opens the second port, and closes 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 may be, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. Each functional unit realized by the processing circuit may be realized by individual hardware, or each functional unit may be realized by a single piece of hardware. When the processing circuit of the control device 200 is a CPU, each function executed by the processing circuit is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory unit. The CPU realizes each function of the processing circuit by reading and executing the program stored in the memory unit. Note that some of the functions of the processing circuit may be realized by dedicated hardware, and some may be realized by software or firmware.

<Operation of the air conditioning device 100>
The operation of the air conditioning device 100 of embodiment 1 will be described. Fig. 2 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state A in the air conditioning device 100 according to embodiment 1. Fig. 3 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state B in the air conditioning device 100 according to embodiment 1. Fig. 4 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state C in the air conditioning device 100 according to embodiment 1. Fig. 5 is a refrigerant circuit diagram showing the flow of refrigerant in an operating state D in the air conditioning device 100 according to embodiment 1. In Figs. 2, 3, 4, and 5, arrows indicate the direction of refrigerant flow.

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

In operating state A, a main circuit and three bypass circuits are formed. As shown in Figure 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 opening and closing 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 this order.

The first bypass circuit is a pipe t6 in which the refrigerant branched from between the subcooling heat exchanger 4 and the fourth check valve 6d of the main circuit flows between the first outdoor four-way valve 2a and the suction side of the compressor 1. The refrigerant flowing through the pipe t6 flows in the order of the second outdoor expansion valve 5b and the subcooling heat exchanger 4, and then merges between the first outdoor four-way valve 2a of the main circuit and the suction side of the compressor 1. The second bypass circuit is in which the refrigerant branched from between the first opening/closing 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 then merges 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 off between the first on-off valve 7a and the first indoor expansion valve 10a 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, before merging between the first three-way valve 8a and the first check valve 6a of the main circuit.

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

In operating state B, a main circuit and two bypass circuits are formed. As shown in Figure 3, 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 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 four-way valve 2a, and the compressor 1 again in this order.

In the first bypass circuit, the refrigerant branched off 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 merges with the refrigerant branched off from between the subcooling heat exchanger 4 and the fourth check valve 6d of the main circuit. In the second bypass circuit, the refrigerant branched off 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 then merges with the refrigerant from the second three-way valve 8b of the main circuit.

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

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

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

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

In operating state D, a main circuit and three bypass circuits are formed. As shown in Figure 5, in the main circuit, the refrigerant flows in the following order: compressor 1, first outdoor four-way valve 2a, second check valve 6b, first three-way valve 8a, first indoor heat exchanger 9a, first indoor expansion valve 10a, second on-off valve 7b, third check valve 6c, subcooling heat exchanger 4, first outdoor expansion valve 5a, first outdoor heat exchanger 3a, first outdoor four-way valve 2a, 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 then merges between the first indoor expansion valve 10a and the second opening and closing 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 then merges between the first indoor expansion valve 10a and the second opening and closing valve 7b of the main circuit. In the third bypass circuit, the refrigerant branched from between the subcooling heat exchanger 4 and the first outdoor expansion valve 5a of the main circuit flows through the second outdoor expansion valve 5b and the subcooling heat exchanger 4, and then merges between the first outdoor four-way valve 2a and the compressor 1 of the main circuit.

<Modification 1>
In the first modification of the first embodiment, two types of heat transfer media, refrigerant and water, form independent circuits without being mixed, and only heat exchange is performed 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, a plate heat exchanger, a shell-and-tube heat exchanger, or the like is used.

Figure 6 is a refrigerant circuit diagram and a water circuit diagram of an air conditioning apparatus 100 relating to variant 1 of embodiment 1. Note that the same parts as in Figure 1 are given the same reference numerals and their explanations are omitted. In variant 1, the configurations of the relay unit 102, the first indoor unit 103a, the second indoor unit 103b and the third indoor unit 103c in the air conditioning apparatus 100 of embodiment 1 are different.

The relay unit 102 is equipped with 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 three-way valve 15a, a second mixed three-way valve 15b, a third mixed three-way valve 15c, a first diverting three-way valve 16a, a second diverting three-way valve 16b and a third diverting three-way valve 16c.

The first on-off valve 7a is connected to the supply 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 supply pipe t10 of the outdoor unit 101 and water, which is 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 supply pipe t10 of the outdoor unit 101 and water, which is a heat medium.

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

The discharge 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 diverted three-way valve 16a is connected between the second pump 14b, the first indoor heat exchanger 9a, and the first pump 14a. The second diverted three-way valve 16b is connected between the second pump 14b, the second indoor heat exchanger 9b, and the first pump 14a. The third diverted 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 branched flow three-way valve 16a, the second branched flow three-way valve 16b, and the third branched flow 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 diversion three-way valve 16a, the second diversion three-way valve 16b and the third diversion three-way valve 16c are switched depending on the operating state of the air conditioning unit 100.

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

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

In the "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 to the first check valve 6a and refrigerant from the outflow pipe t10 does not flow in. In the "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 to the first check valve 6a and refrigerant from the outflow pipe t10 does not flow in.

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

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

<Operation of the air conditioning device 100 according to Modification 1>
The flow of water in the air conditioning device 100 according to the first modification of the first embodiment will be described. The cold water or hot water generated in 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. The distribution of the 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 branch three-way valve 16a, the second branch three-way valve 16b, and the third branch three-way valve 16c.

The flow of refrigerant in operating state A of the air conditioning apparatus 100 relating to variant 1 of embodiment 1 is explained. Figure 7 is a refrigerant circuit diagram and a water circuit diagram in operating state A of the air conditioning apparatus 100 relating to variant 1 of embodiment 1. The flow of refrigerant in the outdoor unit 101 is the same as that in Figure 2.

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

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

The flow of refrigerant in operating state B of the air conditioning apparatus 100 according to variant 1 of embodiment 1 is explained. Figure 8 is a refrigerant circuit diagram and a water circuit diagram in operating state B of the air conditioning apparatus 100 according to variant 1 of embodiment 1. The flow of refrigerant in the outdoor unit 101 is the same as that in Figure 3.

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

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

The flow of refrigerant in the air conditioning apparatus 100 according to the first modified example of the first embodiment in operating state C is explained. Figure 9 is a refrigerant circuit diagram and a water circuit diagram in the air conditioning apparatus 100 according to the first modified example of the first embodiment in operating state C. The flow of refrigerant in the outdoor unit 101 is the same as that in Figure 4.

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

In the bypass circuit, the refrigerant branched off between the subcooling heat exchanger 4 and the first outdoor expansion valve 5a in the main circuit flows to the second outdoor expansion valve 5b and the subcooling heat exchanger 4, and then merges between the first outdoor four-way valve 2a and the compressor 1 in the main circuit.

The flow of refrigerant in the air conditioning apparatus 100 according to the first modified example of the first embodiment in operating state D is explained. Figure 10 is a refrigerant circuit diagram and a water circuit diagram in the air conditioning apparatus 100 according to the first modified example of the first embodiment in operating state D. Note that the flow of refrigerant in the outdoor unit 101 is the same as that in Figure 5.

In the operating state D, a 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 again the compressor 1 in that order. In addition, in the main circuit, the refrigerant branched 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 merges with the refrigerant flowing out of the first relay four-way valve 13a.

In the bypass circuit, the refrigerant branched off between the subcooling heat exchanger 4 and the first outdoor expansion valve 5a in the main circuit flows to the second outdoor expansion valve 5b and merges between the first outdoor four-way valve 2a and the compressor 1 in the main circuit.

The subcooling heat exchanger 4 of the air conditioning device 100 of the first embodiment exchanges heat between the refrigerant flowing in the pipe that branches off between the sixth point p6 and the fifth point p5 and connects between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing in the fifth pipe t5. The refrigerant may branch off 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. The air conditioning device 100 of the first embodiment is equipped with five check valves, namely, 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, in the outdoor unit 101. According to the air conditioning device 100 of the first embodiment, the five valves can be used to counterflow the refrigerant in the subcooling heat exchanger 4, so that the size of the outdoor unit 101 can be suppressed.

Furthermore, according to the air conditioning apparatus 100 of embodiment 1, five valves can be used to realize "counter-flow of the supercooling heat exchanger 4 in both cooling and heating operation" and "a two-pipe system capable of simultaneous cooling and heating operation."

Embodiment 2.
Next, an air conditioning device 100 according to embodiment 2 will be described. FIG. 11 is a refrigerant circuit diagram of the air conditioning device 100 according to embodiment 2. The outdoor unit 101 of the air conditioning device 100 according to embodiment 2 has 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 in addition to the air conditioning device 100 shown in embodiment 1. The sixth check valve 6f plays the role of the first outdoor expansion valve 5a in FIG. 1. The configurations of the relay unit 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. 1. In FIG. 11, the same parts as those in FIG. 1 are given the same reference numerals, and the different parts will be described.

<Outdoor unit 101>
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 heating operation, and is closed to prevent the refrigerant from flowing during 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 in parallel to the first outdoor four-way valve 2a to the compressor 1. The second outdoor four-way valve 2b switches the flow direction of the refrigerant discharged from the compressor 1 and outputs it, 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 the "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 states of the first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are cooling operation, the control device 200 opens the first ports, closes the second ports, and opens the third ports of the first three-way valve 8a, the second three-way valve 8b, and the third three-way valve 8c.

In the case of "operation 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 opening/closing valve 7a, and closes the second opening/closing 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 first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are in operation state B, the control device 200 opens the first port, opens the second port, and opens the third port of the first three-way valve 8a of the first indoor unit 103a performing heating operation. The control device 200 opens the first port, closes the second port, and opens the third port of the second three-way valve 8b of the second indoor unit 103b performing cooling operation. The first port of the third three-way valve 8c of the third indoor unit 103c performing cooling operation is opened, the second port is closed, and the third port is opened.

In the case of "operation 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 opening/closing valve 7a, and opens the second opening/closing 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 first indoor unit 103a, the second indoor unit 103b, and the third indoor unit 103c are in operation 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 performing heating operation. The control device 200 opens the first port, the second port, and the third port of the second three-way valve 8b of the second indoor unit 103b performing heating operation. The first port of the third three-way valve 8c of the third indoor unit 103c performing cooling operation is opened, the second port is closed, and the third port is 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 opening/closing valve 7a, and closes the second opening/closing 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, opens the second port, and closes 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 the air conditioning device 100>
The operation of the air conditioning device 100 of the second embodiment will be described. FIG. 12 is a refrigerant circuit diagram showing the flow of refrigerant in the operating state A in the air conditioning device 100 according to the second embodiment. FIG. 13 is a refrigerant circuit diagram showing the flow of refrigerant in the operating state B in the air conditioning device 100 according to the second embodiment. FIG. 14 is a refrigerant circuit diagram showing the flow of refrigerant in the operating state C in the air conditioning device 100 according to the second embodiment. FIG. 15 is a refrigerant circuit diagram showing the flow of refrigerant in the operating state D in the air conditioning device 100 according to the second embodiment. In FIGS. 12, 13, 14, and 15, the arrows indicate the direction of the refrigerant flow. The configurations of the relay unit 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. 1. In FIGS. 12, 13, 14, and 15, the same parts as those in FIG. 1 are given the same reference numerals, and the different parts will be described.

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

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

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

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

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

In the bypass circuit, the refrigerant branched off 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, before merging between the second three-way valve 8b and the first check valve 6a of the main circuit.

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

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

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

In operating state D, a main circuit and four bypass circuits are formed. In the main circuit, as shown in FIG. 15, the refrigerant flows in the following order: compressor 1, first outdoor four-way valve 2a, second check valve 6b, first three-way valve 8a, first indoor heat exchanger 9a, first indoor expansion valve 10a, second on-off valve 7b, third check valve 6c, subcooling heat exchanger 4, first outdoor expansion valve 5a, first outdoor heat exchanger 3a, first outdoor four-way valve 2a, 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 then merges between the first indoor expansion valve 10a and the second opening and closing 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 then merges between the first indoor expansion valve 10a and the second opening and closing valve 7b of the main circuit. In the third bypass circuit, the refrigerant branched from between the subcooling heat exchanger 4 and the first outdoor expansion valve 5a of the main circuit flows through the second outdoor expansion valve 5b and the subcooling heat exchanger 4, and then merges between the first outdoor four-way valve 2a and the compressor 1 of the main circuit. In the fourth bypass circuit, the refrigerant branched off between the sixth check valve 6f and the first outdoor expansion valve 5a in the main circuit flows to the third outdoor expansion valve 5c, the second outdoor heat exchanger 3b, and the second outdoor four-way valve 2b, and then merges with the refrigerant between the first outdoor four-way valve 2a and the compressor 1 in the main circuit.

<Modification 1>
In the first modification of the second embodiment, two types of heat transfer media, refrigerant and water, form independent circuits without being mixed, and only heat exchange is performed through the first refrigerant-water heat exchanger 12a and the second refrigerant-water heat exchanger 12b. For example, a plate heat exchanger, a shell-and-tube heat exchanger, or the like is used as the refrigerant-water heat exchanger.

Figure 16 is a refrigerant circuit diagram and a water circuit diagram of an air conditioning apparatus 100 relating to variant 1 of embodiment 2. Note that the same parts as in Figure 11 are given the same reference numerals and their explanations are omitted. In variant 1 of embodiment 2, the configurations of the relay unit 102, the first indoor unit 103a, the second indoor unit 103b and the third indoor unit 103c in the air conditioning apparatus 100 of embodiment 2 are different.

The configurations of the relay unit 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 relay unit 102, the first indoor unit 103a, the second indoor unit 103b and the third indoor unit 103c of variant 1 of embodiment 1 shown in Figure 6.

<Control device 200>
In the case of "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. 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 to the first check valve 6a and does not allow refrigerant to flow in from the outflow pipe t10. 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 to the first check valve 6a and does not allow refrigerant to flow in from the outflow pipe t10.

In the "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 opening/closing valve 7a, and closes the second opening/closing 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 "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 opening/closing valve 7a, and opens the second opening/closing 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 "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 outflow pipe t10 flows into the first refrigerant-water heat exchanger 12a and the refrigerant flowing out from the second refrigerant-water heat exchanger 12b does not flow in. In "operating state B", the control device 200 switches the second relay four-way valve 13b so that the refrigerant flowing out from the second indoor expansion valve 10b flows into the first check valve 6a and the refrigerant from the outflow pipe t10 does not flow in.

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

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

The operation of the outdoor unit 101 in the operating state A, operating state B, operating state C, and operating state D of the outdoor unit 101 in the air conditioning apparatus 100 relating to variant example 1 of embodiment 2 is similar to the operation of the outdoor unit 101 in the operating state A, operating state B, operating state C, and operating state D of the outdoor unit 101 in the air conditioning apparatus 100 described in embodiment 2.

The operation of the repeater 102 in the air conditioning apparatus 100 relating to variant 1 of embodiment 2 in operation state A, operation state B, operation state C and operation state D is the same as the operation of the repeater 102 in the air conditioning apparatus 100 described in variant 1 of embodiment 1.

The operation of the first indoor unit 103a, the second indoor unit 103b and the third indoor unit 103c in the air conditioning apparatus 100 relating to variant 1 of embodiment 2 in operating state A, operating state B, operating state C and operating state D are the same as the operation of the first indoor unit 103a, the second indoor unit 103b and the third indoor unit 103c in the air conditioning apparatus 100 described in variant 1 of embodiment 1.

The subcooling heat exchanger 4 of the air conditioning device 100 of the second embodiment exchanges heat between the refrigerant flowing in the pipe that branches off between the sixth point p6 and the fifth point p5 and connects between the first outdoor four-way valve 2a and the suction side of the compressor 1, and the refrigerant flowing in the fifth pipe t5. The refrigerant may branch off 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. The air conditioning device 100 of the second embodiment is equipped with six check valves, namely, 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, in the outdoor unit 101. According to the air conditioning device 100 of the second embodiment, the six valves can be used to counterflow the refrigerant in the subcooling heat exchanger 4, so that the size of the outdoor unit 101 can be suppressed.

Furthermore, according to the air conditioning apparatus 100 of embodiment 2, six valves can be used to realize "counter-flow operation of the subcooling heat exchanger 4 in both cooling and heating operation" and "a two-pipe system capable of simultaneous cooling and heating operation."

In the first and second embodiments, the outgoing pipe t10 is also referred to as the first pipe, the return pipe t11 is also referred to as the second pipe, the first outdoor four-way valve 2a is also referred to as the first switching valve, and the second outdoor four-way valve 2b is also referred to as the second switching valve. The subcooling heat exchanger 4 in the first and second embodiments is also referred to as the refrigerant-to-refrigerant heat exchanger. 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 referred to as the sixth valve.

Embodiments 1 and 2 are presented as examples and are not intended to limit the scope of the claims. Embodiments 1 and 2 can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit 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, 6e Fifth check valve, 6f Sixth check valve, 7a First opening/closing valve, 7b Second opening/closing 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 flow three-way valve, 15b second mixed flow three-way valve, 15c third mixed flow three-way valve, 16a first diverting three-way valve, 16b second diverting three-way valve, 16c third diverting three-way valve, 100 air conditioning device, 101 outdoor unit, 102 relay unit, 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, p4 fourth point, p5 fifth point, p6 sixth point, p7 seventh point, t1 first pipe, t2 second pipe, t3 third pipe, t4 4th pipe, t5 5th pipe, t6 6th pipe, t10 supply pipe, t11 return pipe, t12a, t12b, t12c, t13a, t13b, t13c pipe, r rectifier circuit, A, B, C, D operating state.

Claims (6)

an outdoor unit including 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 flows from the outdoor unit to the indoor unit;
a second pipe through which the refrigerant flows out of the indoor unit and into the outdoor unit,
The outdoor unit is
a rectifier circuit that determines a flow direction of the refrigerant flowing out from the outdoor unit to the first pipe and a flow direction of the refrigerant flowing into the outdoor unit via the second pipe;
a refrigerant heat exchanger that cools a refrigerant flowing into a suction side of the compressor with the refrigerant diverted from the refrigerant flowing into the rectification 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;
Among two points in the first pipe, a first point and a second point are located closer to the first outdoor heat exchanger, and among two points in the second pipe, a third point and a fourth point are located closer to 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 includes:
a first valve provided in the second pipe to allow the refrigerant in the second pipe to flow from the third point to the fourth point and to prevent the refrigerant from flowing in the reverse direction;
a second 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 to prevent the refrigerant from flowing in the reverse direction;
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 to prevent the refrigerant from flowing in the reverse direction;
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 to prevent the refrigerant from flowing in the reverse direction;
The outdoor unit is
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 to prevent the refrigerant from flowing in the reverse direction;
a sixth valve provided in the first pipe, which 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 prevents the refrigerant from flowing in the reverse direction;
a fifth pipe connecting the fifth point and the sixth point and through which the refrigerant flows from the sixth point to the fifth point;
The refrigerant heat exchanger includes:
An air conditioning apparatus which exchanges heat between the refrigerant flowing through a pipe that branches off from any one of a 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 connects between the first switching valve and a suction side of the compressor, and the refrigerant flowing through the fifth pipe. 2. The air conditioner according to claim 1, further comprising a second outdoor expansion valve that reduces the pressure of the refrigerant branched off from between the sixth point and the fifth point. 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 to prevent the refrigerant from flowing during cooling. the sixth valve is a check valve;
The air-conditioning apparatus 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 and configured to switch a flow direction of the refrigerant discharged from the compressor to switch between the cooling mode and the heating mode;
a second outdoor heat exchanger in which heat exchange of the refrigerant output from the second switching valve is performed;
The air conditioner according to claim 4 , further comprising: a third outdoor expansion valve provided in the first pipe between the second outdoor heat exchanger and the first point. A plurality of the indoor units are provided,
a control device that simultaneously performs the cooling and heating of the plurality of indoor units in a mixed manner,
The control device includes:
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 refrigerant-to-refrigerant heat exchanger, and the fourth valve;
a first bypass flow path that branches off from the first main circuit between the refrigerant-refrigerant heat exchanger and the fourth valve, through which the refrigerant flows in this order through the second outdoor expansion valve and the refrigerant-refrigerant heat exchanger, and joins the first main circuit between the first switching valve and the suction side of the compressor;
a second bypass flow path is formed in the outdoor unit, the second bypass flow path branches off from the first main circuit between the compressor and the first switching valve, the refrigerant flows through the second switching valve, the second outdoor heat exchanger, and the third outdoor expansion valve in this order, and the second bypass flow path joins the first main circuit between the first outdoor expansion valve and the fifth valve,
When the indoor units performing the cooling function and the indoor units performing the heating function are mixed, and the cooling load of the indoor units is greater than the heating load of the indoor units,
The first main circuit is formed in the outdoor unit,
When the indoor units performing the cooling function and the indoor units performing the heating function are mixed, and the heating load of the indoor units is greater than the cooling load of the indoor units, or when all of the indoor units perform the heating function,
a second main circuit in which the refrigerant flows in the order of the third valve, the refrigerant heat exchanger, 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; and
a third bypass flow path that branches off from the second main circuit between the refrigerant-refrigerant heat exchanger and the first outdoor expansion valve, through which the refrigerant flows through the second outdoor expansion valve and the refrigerant-refrigerant heat exchanger in this order, and that joins the second main circuit between the first switching valve and the suction side of the compressor;
6. The air conditioning apparatus according to claim 5, wherein operation is controlled so that a fourth bypass flow path is formed within the outdoor unit, the fourth bypass flow path branching off from between the sixth valve and the refrigerant-to-refrigerant heat exchanger of the second main circuit, through which the refrigerant flows in this order through the second outdoor expansion valve and the refrigerant-to-refrigerant heat exchanger, and merging between the first switching valve and the suction side of the compressor of the second main circuit.

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