Air conditioning unit

Abstract

An air conditioning device (1a) includes a heat source side unit (2), a plurality of utilization side units (3a, 3b, 3c, 3d), an intermediate unit (4a, 4b, 4c, 4d), and three or more communication pipes (5, 6, 7). The communication pipes (5, 6, 7) connect the heat source side unit (2) and the intermediate unit (4a, 4b, 4c, 4d). The intermediate unit (4a, 4b, 4c, 4d) includes an ejector (41a, 41b, 41c, 41d) and a gas-liquid separator (42a, 42b, 42c, 42d). The ejector (41a, 41b, 41c, 41d) increases the pressure of the refrigerant. The gas-liquid separator (42a, 42b, 42c, 42d) allows the refrigerant flowing out of the ejector (41a, 41b, 41c, 41d) to flow in. The refrigerant having released heat in the utilization side unit (3a, 3b, 3c, 3d) performing a heating operation is configured not to be pressurized in the ejector (41a, 41b, 41c, 41d).

Description

Technical Field

[0001] The present disclosure relates to an air conditioning device. Background Art

[0002] At present, among air conditioners having a plurality of utilization units, there is known an air conditioner capable of mixing a utilization unit in a cooling operation state with a utilization unit in a heating operation state. As such an air conditioner, for example, Japanese Patent Publication No. 2005-337659 (Patent Document 1) discloses a three-pipe air conditioner having three refrigerant communication pipes. Summary of the invention

[0003] Technical problem to be solved by the invention

[0004] However, in the air conditioning device disclosed in the above-mentioned Patent Document 1, there is still room for improvement in terms of power recovery.

[0005] Technical solutions adopted to solve technical problems

[0006] The air conditioning device of the first viewpoint includes a heat source side unit, a plurality of utilization side units, an intermediate unit, and three or more connecting pipes. The heat source side unit has a compressor and a heat source side heat exchanger. The plurality of utilization side units have utilization side heat exchangers. The intermediate unit is switched in such a way that the plurality of utilization side heat exchangers individually function as evaporators or heat emitters of the refrigerant. Three or more connecting pipes connect the heat source side unit and the intermediate unit. The intermediate unit has an ejector and a gas-liquid separator. The ejector increases the pressure of the refrigerant. The gas-liquid separator is for the refrigerant flowing out of the ejector to flow in. The refrigerant after heat release in the utilization side unit performing heating operation is configured not to be increased in pressure in the ejector.

[0007] In the air conditioning device of the first aspect, the intermediate unit has an ejector for recovering power. In addition, the refrigerant after releasing heat in the utilization side unit performing heating operation is configured not to be pressurized in the ejector. Therefore, it is possible to make the ejector inactive for the utilization side heat exchanger performing heating operation with relatively small benefits, and to use the ejector to increase the pressure of the refrigerant after heat exchange in the utilization side heat exchanger performing operation with relatively large benefits. Therefore, it is possible to recover power by using the ejector of the intermediate unit.

[0008] In the air-conditioning apparatus according to the second aspect, in addition to the air-conditioning apparatus according to the first aspect, the refrigerant evaporated in the usage-side unit performing the cooling operation is configured to flow through the ejector.

[0009] In the air conditioning apparatus of the second aspect, the refrigerant evaporated in the utilization side heat exchanger that performs a relatively large cooling operation can be pressurized by the ejector. Therefore, an air conditioning apparatus that recovers power can be realized.

[0010] On the basis of the air conditioning device of the first viewpoint or the second viewpoint, in the air conditioning device of the third viewpoint, the intermediate unit further comprises a first pipe, a first valve, a second pipe and a second valve. The first pipe is a pipe for allowing the refrigerant to flow between the heat source side heat exchanger and the utilization side heat exchanger. The first valve is provided on the first pipe. The second pipe is a pipe branched from the first pipe between the heat source side heat exchanger and the first valve and used for the refrigerant to flow to the driving inlet of the ejector. The second valve is provided on the second pipe. The air conditioning device further comprises a control unit for controlling the first valve and the second valve.

[0011] In the air conditioning device of the third viewpoint, by using the control unit to open the first valve and to close the second valve, the refrigerant flowing in the utilization side heat exchanger through the first pipe can be supplied to the heat source side heat exchanger without passing through the ejector. In addition, by using the control unit to close the first valve and to open the second valve, the refrigerant flowing in the utilization side heat exchanger through the second pipe, the ejector, and the gas-liquid separator can be supplied to the heat source side heat exchanger in a state of being pressurized in the ejector. In this way, through the first valve and the second valve, it is possible to select whether the driving flow flows to the ejector and whether the driving flow does not flow to the ejector. Therefore, it is possible to select whether to make the ejector work or not.

[0012] In addition to the air conditioning apparatuses according to the first to third aspects, in an air conditioning apparatus according to a fourth aspect, the intermediate unit has a plurality of ejectors, and each ejector is connected to each usage-side unit.

[0013] The air conditioning apparatus according to the fourth aspect is also applicable to a refrigerant circuit in which each ejector can increase the pressure of the refrigerant in each usage-side unit.

[0014] In the air conditioning apparatus according to the first to third aspects, in the air conditioning apparatus according to a fifth aspect, the ejector is connected to a plurality of usage-side units.

[0015] The air conditioning apparatus according to the fifth aspect is also applicable to a refrigerant circuit in which one ejector can increase the pressure of the refrigerant in a plurality of usage-side units.

[0016] In the air-conditioning apparatus according to the first to fifth aspects, in the air-conditioning apparatus according to the sixth aspect, the compressor discharges the refrigerant in a supercritical state.

[0017] In the air conditioning apparatus of the sixth aspect, since the refrigerant in the supercritical state flows in a part of the intermediate unit, the refrigerant in the supercritical state can be used as the driving flow. Therefore, the effect of using the ejector can be improved.

[0018] In the air-conditioning apparatus according to the sixth aspect, in the air-conditioning apparatus according to a seventh aspect, the refrigerant compressed in the compressor contains carbon dioxide.

[0019] In the air conditioning apparatus of the seventh aspect, the refrigerant containing carbon dioxide can be in a supercritical state. Therefore, an air conditioning apparatus with an enhanced effect of using the ejector can be easily realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic configuration diagram of the air conditioning apparatus according to the first embodiment.

[0021] Figure 2 This is a block diagram schematically showing the air conditioning apparatus according to the first embodiment.

[0022] Figure 3 This is a schematic configuration diagram of the air-conditioning apparatus according to the first embodiment (showing the flow of refrigerant during cooling only operation).

[0023] Figure 4 This is a schematic configuration diagram of the air-conditioning apparatus according to the first embodiment (showing the flow of refrigerant during cooling-main operation).

[0024] Figure 5 This is a schematic configuration diagram of the air-conditioning apparatus according to the first embodiment (showing the flow of refrigerant during cooling and heating equalization operation).

[0025] Figure 6 This is a schematic configuration diagram of the air-conditioning apparatus according to the first embodiment (showing the flow of refrigerant during heating main operation).

[0026] Figure 7 This is a schematic configuration diagram of the air-conditioning apparatus according to the first embodiment (showing the flow of refrigerant during heating only operation).

[0027] Figure 8 It is a schematic configuration diagram of an air conditioning apparatus according to a second embodiment.

[0028] Fig. 9 It is a schematic configuration diagram of an air-conditioning apparatus according to a second embodiment (showing the flow of refrigerant during cooling only operation).

[0029] Fig.10 It is a schematic configuration diagram of an air-conditioning apparatus according to a second embodiment (showing the flow of refrigerant during cooling-main operation).

[0030] Fig.11 It is a schematic configuration diagram of an air-conditioning apparatus according to a second embodiment (showing the flow of refrigerant during cooling and heating equalization operation).

[0031] Fig.12It is a schematic configuration diagram of an air-conditioning apparatus according to a second embodiment (showing the flow of refrigerant during heating main operation).

[0032] Fig.13 It is a schematic configuration diagram of an air-conditioning apparatus according to a second embodiment (showing the flow of refrigerant during heating only operation). DETAILED DESCRIPTION

[0033] An air conditioning device according to an embodiment of the present disclosure will be described with reference to the drawings.

[0034] (1) Overall structure

[0035] like Figure 1 As shown, an air conditioning device 1a according to an embodiment of the present disclosure is a device that uses a vapor compression refrigeration cycle to perform indoor cooling and heating in a building or the like. The air conditioning device 1a includes a heat source side unit 2, a plurality of (here four) utilization side units 3a, 3b, 3c, 3d, a plurality of (here four) intermediate units 4a, 4b, 4c, 4d, a first communication pipe 5, a second communication pipe 6, a third communication pipe 7, a fourth communication pipe 8a, 8b, 8c, 8d, a fifth communication pipe 9a, 9b, 9c, 9d, Figure 2 The control unit 50 shown. The refrigerant circuit of the air conditioner 1a is formed by connecting the heat source side unit 2, the use side units 3a, 3b, 3c, 3d, the intermediate units 4a, 4b, 4c, 4d, and the communication pipes 5, 6, 7, 8a, 8b, 8c, 8d, 9a, 9b, 9c, 9d. The air conditioner 1a is configured so that each use side unit 3a, 3b, 3c, 3d can perform cooling operation or heating operation individually through the intermediate units 4a, 4b, 4c, 4d.

[0036] The control unit 50 controls the components of the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate units 4a, 4b, 4c, 4d.

[0037] (1-2) Detailed structure

[0038] (1-2-1) Connecting pipes

[0039] There are three connecting pipes connecting the heat source side unit 2 and the intermediate units 4a, 4b, 4c, and 4d. Here, the first connecting pipe 5, the second connecting pipe 6, and the third connecting pipe 7 connect the heat source side unit 2 and the intermediate units 4a, 4b, 4c, and 4d. The first connecting pipe 5 is a high-pressure connecting pipe through which a refrigerant having a pressure higher than that of the refrigerant in the third connecting pipe 7 passes. The second connecting pipe 6 is a high-pressure (at least high pressure of high and low pressure) connecting pipe through which a refrigerant having a pressure higher than that of the refrigerant in the third connecting pipe 7 passes. The third connecting pipe is a gas connecting pipe on the low-pressure side.

[0040] The first communication pipe 5 includes a confluence pipe portion extending from the heat source side unit 2, and a plurality of (here, four) branch pipe portions 5a, 5b, 5c, 5d branching out in front of the intermediate units 4a, 4b, 4c, 4d. The second communication pipe 6 includes a confluence pipe portion extending from the heat source side unit 2, and a plurality of (here, four) branch pipe portions 5a, 6b, 6c, 6d branching out in front of the intermediate units 4a, 4b, 4c, 4d. The third communication pipe 7 includes a confluence pipe portion extending from the heat source side unit 2, and a plurality of (here, four) branch pipe portions 7a, 7b, 7c, 7d branching out in front of the intermediate units 4a, 4b, 4c, 4d.

[0041] The fourth communication pipes 8a, 8b, 8c, 8d and the fifth communication pipes 9a, 9b, 9c, 9d connect the side units 3a, 3b, 3c, 3d and the intermediate units 4a, 4b, 4c, 4d. The fourth communication pipes 8a, 8b, 8c, 8d are connected to the branch pipes 5a, 5b, 5c, 5d of the first communication pipe 5 through the intermediate units 4a, 4b, 4c, 4d. The fifth communication pipes 9a, 9b, 9c, 9d are connected to the branch pipes 6a, 6b, 6c, 6d of the second communication pipe 6 and the branch pipes 7a, 7b, 7c, 7d of the third communication pipe 7 through the intermediate units 4a, 4b, 4c, 4d.

[0042] As described above, the air-conditioning apparatus 1 a of the present embodiment is a three-pipe air-conditioning apparatus having three communication pipes connecting the heat-source-side unit 2 and the intermediate units 4 a , 4 b , 4 c , and 4 d .

[0043] (1-2-2) Heat source side unit

[0044] The heat source side unit 2 is installed on the roof of a building or around the building. The heat source side unit 2 is connected to the utilization side units 3a, 3b, 3c, 3d through the first communication pipe 5, the second communication pipe 6, the third communication pipe 7, the fourth communication pipe 8a, 8b, 8c, 8d, the fifth communication pipe 9a, 9b, 9c, 9d and the intermediate unit 4a, 4b, 4c, 4d, and constitutes a part of the refrigerant circuit.

[0045] The heat source side unit 2 mainly has a compressor 21, one or more (here three) switching mechanisms 22a, 22b, 22c, one or more (here two) heat source side heat exchangers 23a, 23b, one or more (here two) heat source side expansion valves 24a, 24b, an ejector 25, and a gas-liquid separator 26.

[0046] The compressor 21 is a device that compresses low-pressure refrigerant to high pressure. Here, a closed-type compressor in which a rotary, scroll, or other positive displacement compression element (not shown) is driven to rotate by a compressor motor is used as the compressor 21. In addition, here, the compressor motor can control its rotation speed by an inverter or the like, thereby controlling the capacity of the compressor 21.

[0047] In the present embodiment, the compressor 21 discharges the refrigerant in a supercritical state. Therefore, the refrigerant in a supercritical state flows in a part of the refrigerant circuit. The refrigerant compressed by the compressor 21 includes carbon dioxide. Here, carbon dioxide is used as the refrigerant.

[0048] The switching mechanisms 22a, 22b, and 22c are four-way switching valves capable of switching the flow direction of the refrigerant in the refrigerant circuit.

[0049] The first switching mechanism 22a and the second switching mechanism 22b are electric valves capable of switching between a heat release state on the heat source side and an evaporation state on the heat source side. In the heat release state on the heat source side, the heat exchangers 23a and 23b on the heat source side act as heat releasers of the refrigerant. In the evaporation state on the heat source side, the heat exchangers 23a and 23b on the heat source side act as evaporators of the refrigerant.

[0050] The first switching mechanism 22a is a device that can switch the refrigerant flow in the refrigerant circuit in the following manner: when the first heat source side heat exchanger 23a functions as a heat radiator of the refrigerant, the discharge side of the compressor 21 is connected to the gas side of the first heat source side heat exchanger 23a (see Figure 1 When the first heat source side heat exchanger 23a acts as an evaporator of the refrigerant, the suction side of the compressor 21 is connected to the gas side of the first heat source side heat exchanger 23a (refer to Figure 1 The solid line of the first switching mechanism 22a).

[0051] The second switching mechanism 22b is a device that can switch the refrigerant flow in the refrigerant circuit in the following manner: when the second heat source side heat exchanger 23b functions as a heat radiator of the refrigerant, the discharge side of the compressor 21 is connected to the gas side of the second heat source side heat exchanger 23b (see Figure 1 When the second heat source side heat exchanger 23b acts as an evaporator of the refrigerant, the suction side of the compressor 21 is connected to the gas side of the second heat source side heat exchanger 23b (refer to Figure 1 The second switching mechanism 22b is represented by a solid line).

[0052] The third switching mechanism 22c is a device that can switch the refrigerant flow in the refrigerant circuit in the following manner: when the refrigerant discharged from the compressor 21 is sent to the second communication pipe 6, the discharge side of the compressor 21 is connected to the second communication pipe 6 (see Figure 1 In the case where the refrigerant flowing in the second communicating pipe 6 is sent to the suction side of the compressor 21, the suction side of the compressor 21 is connected to the second communicating pipe 6 (refer to Figure 1 The third switching mechanism 22c is represented by a dotted line).

[0053] The switching mechanisms 22a, 22b, and 22c are not limited to those formed by four-way switching valves, and may be configured to switch the refrigerant flow direction as described above by combining a plurality of electromagnetic valves and refrigerant pipes, for example.

[0054] The first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b perform heat exchange between the refrigerant and the outdoor air. The first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b are heat exchangers that function as radiators of the refrigerant or as evaporators of the refrigerant.

[0055] The first heat source side expansion valve 24a and the second heat source side expansion valve 24b can change the opening. By adjusting the opening of the first heat source side expansion valve 24a and the second heat source side expansion valve 24b, the degree of decompression is adjusted. Specifically, the first heat source side expansion valve 24a is an electric expansion valve capable of adjusting the opening, and the flow rate of the refrigerant flowing in the first heat source side heat exchanger 23a is adjusted. The second heat source side expansion valve 24b is an electric expansion valve capable of adjusting the opening, and the flow rate of the refrigerant flowing in the second heat source side heat exchanger 23b is adjusted.

[0056] The ejector 25 uses the driving flow to increase the pressure of the refrigerant after heat exchange in the heat source side heat exchangers 23a and 23b. In detail, the ejector 41 is a pressure increasing mechanism provided in the refrigerant circuit, which uses the high-pressure refrigerant as the driving flow to attract the low-pressure refrigerant and increase its pressure, and supplies the increased-pressure refrigerant to the compressor 21.

[0057] The ejector 25 includes a driving flow inlet 25a, a suction flow inlet 25b, and a discharge port 25c. The driving flow inlet 25a allows the driving flow to flow in. The suction flow inlet 25b allows the refrigerant that has undergone heat exchange in the heat source side heat exchangers 23a and 23b to flow in. The discharge port 25c increases the pressure of the refrigerant that has undergone heat exchange in the heat source side heat exchangers 23a and 23b and discharges it. The refrigerant discharged from the discharge port 25c is in a gas-liquid two-phase state.

[0058] The gas-liquid separator 26 allows the refrigerant flowing out of the ejector 25 to flow in. The gas-liquid separator 26 includes a refrigerant inlet 26a, a liquid-side outlet 26b, and a gas-side outlet 26c. The refrigerant inlet 26a is connected to the ejection outlet 25c of the ejector 25. The refrigerant in a gas-liquid two-phase state flows in from the refrigerant inlet 26a. The liquid-side outlet 26b allows the separated liquid refrigerant to flow out. The gas-side outlet 26c allows the separated gas refrigerant to flow out.

[0059] The heat source side unit 2 further includes a heat source side first valve V21 , a heat source side second valve V22 , a heat source side third valve V23 , and a heat source side fourth valve V24 .

[0060] The first heat source side valve V21 is provided on the first heat source side pipe P21, and the first heat source side pipe P21 connects the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b to the first communication pipe 5. Here, the first heat source side valve V21 is an electric valve capable of adjusting the opening degree.

[0061] The second heat source side valve V22 is provided on the second heat source side pipe P22, and the second heat source side pipe P22 connects the first communication pipe 5 and the drive inlet 25a of the ejector 25. The second heat source side pipe P22 branches from a portion of the first heat source side pipe P21 located between the first communication pipe 5 and the first heat source side valve V21. Here, the second heat source side valve V22 is an electric valve that can be opened and closed.

[0062] The third heat source side valve V23 is provided on the third heat source side pipe P23, and the third heat source side pipe P23 connects the second communication pipe 6 and the refrigerant inlet 26a of the gas-liquid separator 26. The third heat source side valve V23 is a check valve that allows only the flow of refrigerant from the second communication pipe 6 to the gas-liquid separator 26. Here, the third heat source side valve V23 is provided between the third switching mechanism 22c and the refrigerant inlet 26a.

[0063] The fourth heat source side valve V24 is provided on the fourth heat source side pipe P24, and the fourth heat source side pipe P24 connects the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b with the liquid side outlet 26b of the gas-liquid separator 26. The fourth heat source side valve V24 is a check valve that allows only the flow of refrigerant from the liquid side outlet 26b to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b. Here, the fourth heat source side valve V24 is provided between the liquid side outlet 26b and the first heat source side expansion valve 24a and the second heat source side expansion valve 24b.

[0064] A first stop valve V25 is provided at a connection portion between the heat source side unit 2 and the first communication pipe 5. A second stop valve V26 is provided at a connection portion between the heat source side unit 2 and the second communication pipe 6. A third stop valve V27 is provided at a connection portion between the heat source side unit 2 and the third communication pipe 7. The first stop valve V25, the second stop valve V26, and the third stop valve V27 are valves that are manually opened and closed.

[0065] (1-2-3) Using the side unit

[0066] The utilization side units 3a, 3b, 3c, 3d are installed on the ceiling of a building or the like by embedding or hanging, or installed on the wall surface of the room by hanging, etc. The utilization side units 3a, 3b, 3c, 3d are connected to the heat source side unit 2 through the first communication pipe 5, the second communication pipe 6, the third communication pipe 7, the fourth communication pipe 8a, 8b, 8c, 8d, the fifth communication pipe 9a, 9b, 9c, 9d and the intermediate units 4a, 4b, 4c, 4d, and constitute a part of the refrigerant circuit.

[0067] Next, the structure of the usage side units 3a, 3b, 3c, 3d is described. The usage side units 3a, 3b, 3c, 3d include a first usage side unit 3a, a second usage side unit 3b, a third usage side unit 3c, and a fourth usage side unit 3d connected in parallel.

[0068] The first user-side unit 3a includes a first user-side heat exchanger 31a and a first user-side expansion valve 32a. The second user-side unit 3b includes a second user-side heat exchanger 31b and a second user-side expansion valve 32b. The third user-side unit 3c includes a third user-side heat exchanger 31c and a third user-side expansion valve 32c. The fourth user-side unit 3d includes a fourth user-side heat exchanger 31d and a fourth user-side expansion valve 32d. The user-side heat exchangers 31a, 31b, 31c, and 31d are connected in series with the user-side expansion valves 32a, 32b, 32c, and 32d.

[0069] The utilization side heat exchangers 31a, 31b, 31c, and 31d are heat exchangers that process indoor air conditioning loads (heat loads) by exchanging heat between the refrigerant and the indoor air. The utilization side heat exchangers 31a, 31b, 31c, and 31d function as evaporators of the refrigerant to cool the indoor air during cooling operation, and function as radiators of the refrigerant to heat the indoor air during heating operation.

[0070] The use-side expansion valves 32a, 32b, 32c, and 32d can change their openings. By adjusting the openings of the use-side expansion valves 32a, 32b, 32c, and 32d, the degree of decompression of the use-side expansion valves 32a, 32b, 32c, and 32d is adjusted. Specifically, the use-side expansion valves 32a, 32b, 32c, and 32d are electric expansion valves capable of adjusting their openings, and perform flow rate adjustment of the refrigerant flowing through the use-side heat exchangers 31a, 31b, 31c, and 31d.

[0071] The first use-side pipes P31a, P31b, P31c, and P31d connect the use-side heat exchangers 31a, 31b, 31c, and 31d with the fourth communication pipes 8a, 8b, 8c, and 8d. In the first use-side pipes P31a, P31b, P31c, and P31d, use-side expansion valves 32a, 32b, 32c, and 32d are arranged between the fourth communication pipes 8a, 8b, 8c, and 8d and the use-side heat exchangers 31a, 31b, 31c, and 31d. The second use-side pipes P32a, P32b, P32c, and P32d connect the use-side heat exchangers 31a, 31b, 31c, and 31d with the fifth communication pipes 9a, 9b, 9c, and 9d.

[0072] In addition, here, an air conditioning apparatus having four usage-side units is described, but the present disclosure is also applicable to a case where a larger or smaller number of usage-side units is connected to one heat-source-side unit 2 to form one refrigerant circuit.

[0073] (1-2-4) Intermediate Unit

[0074] The intermediate units 4a, 4b, 4c, 4d are switched so that the plurality of utilization side heat exchangers 31a, 31b, 31c, 31d individually function as evaporators or radiators of the refrigerant. The intermediate unit 4 is disposed indoors in the building together with the utilization side units 3a, 3b, 3c, 3d. The intermediate units 4a, 4b, 4c, 4d are interposed between the utilization side units 3a, 3b, 3c, 3d and the heat source side unit 2 together with the first communication pipe 5, the second communication pipe 6, the third communication pipe 7, the fourth communication pipe 8a, 8b, 8c, 8d, and the fifth communication pipe 9a, 9b, 9c, 9d, and constitute a part of the refrigerant circuit.

[0075] In the present embodiment, the intermediate units 4a, 4b, 4c, 4d have a plurality of ejectors 41a, 41b, 41c, 41d. In other words, the intermediate units 4a, 4b, 4c, 4d as a whole have a plurality of ejectors 41a, 41b, 41c, 41d. Each ejector 41a, 41b, 41c, 41d is connected to each utilization side unit 3a, 3b, 3c, 3d. Therefore, each ejector 41a, 41b, 41c, 41d can increase the pressure of the refrigerant of each utilization side unit 3a, 3b, 3c, 3d. Here, the refrigerant after heat release in the utilization side unit 3a, 3b, 3c, 3d performing the heating operation is configured so as not to be increased in pressure in the ejectors 41a, 41b, 41c, 41d. In other words, the ejectors 41a, 41b, 41c, and 41d connected to the utilization-side units 3a, 3b, 3c, and 3d that perform the heating operation are configured not to function.

[0076] In addition, the intermediate units 4a, 4b, 4c, 4d further include a plurality of gas-liquid separators 42a, 42b, 42c, 42d. In other words, the intermediate units 4a, 4b, 4c, 4d as a whole further include a plurality of gas-liquid separators 42a, 42b, 42c, 42d. The refrigerant flowing out of each ejector 41a, 41b, 41c, 41d flows into each gas-liquid separator 42a, 42b, 42c, 42d.

[0077] Next, the structures of the intermediate units 4a, 4b, 4c, and 4d are described. In the following description, since the intermediate unit 4a has the same structure as the intermediate units 4b, 4c, and 4d, only the structure of the intermediate unit 4a is described here, and the structures of the intermediate units 4b, 4c, and 4d are respectively marked with symbols "b", "c", or "d" to replace the symbol "a" representing each part of the intermediate unit 4a, and the description of each part is omitted.

[0078] An intermediate unit 4a has an ejector 41a and a gas-liquid separator 42a.

[0079] The ejector 41a increases the pressure of the refrigerant. Specifically, the ejector 41 is a pressure-increasing mechanism provided in the refrigerant circuit, which uses the high-pressure refrigerant as a driving flow to attract and increase the pressure of the low-pressure refrigerant after heat exchange in the utilization-side heat exchanger 31a, and supplies the increased-pressure refrigerant to the connecting pipe on the low-pressure side.

[0080] The ejector 41a does not increase the pressure of the refrigerant flowing in the use-side unit 3a in the heating operation. Here, the ejector 41a increases the pressure of the refrigerant evaporated in the use-side unit 3a in the cooling operation by the driving flow. In addition, the refrigerant evaporated in the use-side unit 3a in the cooling operation can also be not increased in pressure.

[0081] The ejector 41a includes a driving flow inlet 411a, a suction flow inlet 412a, and a discharge port 413a. The driving flow inlet 411a allows the driving flow to flow in. The driving flow inlet 411a is connected to the utilization side heat exchanger 31a that functions as an evaporator of the refrigerant. The suction flow inlet 412a allows the refrigerant evaporated in the evaporator to flow in. The discharge port 413a increases the pressure of the refrigerant evaporated in the evaporator and discharges it. The refrigerant discharged from the discharge port 413c is in a gas-liquid two-phase state.

[0082] The gas-liquid separator 42a allows the refrigerant flowing out of the ejector 41a to flow in. The gas-liquid separator 42a includes a refrigerant inlet 421a, a liquid-side outlet 422a, and a gas-side outlet 423a. The refrigerant inlet 421a is connected to the ejection outlet 413a of the ejector 41a. The refrigerant in a gas-liquid two-phase state flows in from the refrigerant inlet 421a. The liquid-side outlet 422a allows the separated liquid refrigerant to flow out. The gas-side outlet 423a allows the separated gas refrigerant to flow out.

[0083] The intermediate unit 4a also has an intermediate first pipe P41a, an intermediate second pipe P42a, an intermediate third pipe P43a, an intermediate fourth pipe P44a, an intermediate fifth pipe P45a, an intermediate sixth pipe P46a, an intermediate seventh pipe P47a, an intermediate first valve V41a, an intermediate second valve V42a, an intermediate third valve V43a, an intermediate fourth valve V44a, an intermediate fifth valve V45a, and an intermediate sixth valve V46a.

[0084] The first intermediate pipe P41 allows the refrigerant to flow between the heat source side heat exchangers 23a and 23b and the first utilization side heat exchanger 31a. Here, the first intermediate pipe P41 connects the branch pipe portion 5a of the first communication pipe 5 and the fourth communication pipe 8a. The first intermediate pipe P41a is provided with a first intermediate valve V41a. Here, the first intermediate valve V41a is an on-off valve.

[0085] The intermediate second pipe P42a branches from the intermediate first pipe P41a between the heat source side heat exchangers 23a and 23b and the intermediate first valve V41a, and allows the refrigerant to flow to the drive inlet 411a of the ejector 41a. The intermediate second pipe P42a is provided with an intermediate second valve V42a. Here, the intermediate second valve V42a is an on-off valve.

[0086] The third intermediate pipe P43a connects the fifth communication pipe 9a and the branch pipe portion 6a of the second communication pipe 6. The third intermediate pipe P43a is provided with a third intermediate valve V43a. Here, the third intermediate valve V43a is an on-off valve.

[0087] The fourth intermediate pipe P44a branches from the third intermediate pipe P43a between the fifth communication pipe 9a and the third intermediate valve V43a, and allows the refrigerant to flow to the suction inlet 412a of the ejector 41a. The fourth intermediate pipe P44a is provided with a fourth intermediate valve V44a. Here, the fourth intermediate valve V44a is an on-off valve.

[0088] The fifth intermediate pipe P45a connects the liquid outlet 422a of the gas-liquid separator 42a and the fourth communication pipe 8a. The fifth intermediate pipe P45a is provided with a fifth intermediate valve V45a. The fifth intermediate valve V45a is a check valve that allows only the flow of refrigerant from the liquid outlet 422a to the fourth communication pipe 8a.

[0089] The sixth intermediate pipe P46a connects the gas-side outlet 423a of the gas-liquid separator 42a and the branch pipe portion 6a of the second communication pipe 6. The sixth intermediate pipe P46a is provided with a sixth intermediate valve V46a. The sixth intermediate valve V46a is an electric valve.

[0090] The seventh intermediate pipe P47 a connects the gas-side outlet 423 a of the gas-liquid separator 42 a and the branch pipe portion 7 a of the third communication pipe 7 .

[0091] A stop valve is provided at the connection between the intermediate unit 4a and the connecting pipe. The stop valve is a valve that is opened and closed manually. Here, three stop valves are provided at the connection between the intermediate unit 4a and the first to third connecting pipes 5 to 7. Specifically, the three stop valves are provided at the connection between the intermediate unit 4a and the branch pipe portion 5a of the first connecting pipe 5, the connection between the intermediate unit 4a and the branch pipe portion 6a of the second connecting pipe 6, and the connection between the intermediate unit 4a and the branch pipe portion 7a of the third connecting pipe 7. In addition, here, two stop valves are provided at the connection between the intermediate unit 4a and the fourth connecting pipe 8a and the fifth connecting pipe 9a. Specifically, two stop valves are provided at the connection between the intermediate unit 4a and the fourth connecting pipe 8a and the connection between the intermediate unit 4a and the fifth connecting pipe 9a.

[0092] (1-2-5) Control Unit

[0093] Figure 2 The control unit 50 shown controls the components of the heat source side unit 2 , the utilization side units 3 a , 3 b , 3 c , 3 d , and the intermediate unit 4 .

[0094] The control unit 50 is realized by, for example, a computer. The computer includes, for example, a control operation device and a storage device. The control operation device can use a processor. Figure 2The control unit 50 includes a CPU 51 as a processor. For example, the control operation device reads a program stored in the storage device and performs a predetermined image processing, operation processing or sequence processing according to the program. In addition, the control operation device can, for example, write the operation result to the storage device according to the program, or read the information stored in the storage device according to the program. The storage device can be used as a database. The control unit 50 includes a memory 52 as a storage device.

[0095] The control unit 50 controls the compressor 21 and the switching mechanism 22a, 22b, 22c of the heat source side unit 2, the heat source side expansion valve 24a, 24b, the heat source side first valve V21, the utilization side expansion valves 32a, 32b, 32c, 32d of the utilization side units 3a, 3b, 3c, 3d, the intermediate first valve V41a, V41b, V41c, V41d, the intermediate second valve V42a, V42b, V42c, V42d, the intermediate third valve V43a, V43b, V43c, V43d, the intermediate fourth valve V44a, V44b, V44c, V44d and the intermediate sixth valve V46a, V46b, V46c, V46d of the intermediate unit 4.

[0096] Specifically, the control unit 50 controls whether to operate the ejectors 41a, 41b, 41c, 41d by controlling the intermediate first valves V41a, V41b, V41c, V41d to be fully opened or fully closed. In addition, the control unit 50 controls the pressure increase degree of the refrigerant in the ejectors 41a, 41b, 41c, 41d after heat release in the utilization side units 3a, 3b, 3c, 3d by the opening degree of the intermediate second valves V42a, V42b, V42c, V42d.

[0097] In addition, the control unit 50 controls the ejectors 41a, 41b, 41c, 41d in a case where the amount of power recovery is less than a predetermined amount, and in a case where the amount of power recovery is greater than a predetermined amount, the ejectors 41a, 41b, 41c, 41d are activated. For example, the control unit 50 controls the ejectors 41a, 41b, 41c, 41d in a case where the temperature of the temperature sensor provided at the drive inlet 411a, 411b, 411c, 411d is less than a predetermined temperature, and in a case where the temperature of the temperature sensor is greater than a predetermined temperature, the ejectors 41a, 41b, 41c, 41d are activated.

[0098] (1-3) Operation

[0099] The operation of the air-conditioning device 1a of the present embodiment includes full cooling operation, cooling-dominated operation, cooling-equalization operation, heating-dominated operation, and full heating operation. Full cooling operation is an operation in which all the utilization side units 3a, 3b, 3c, and 3d are cooled. Cooling-dominated operation is a cooling-dominated mixing operation in which the sum of the cooling operation loads of the multiple utilization side units 3a, 3b, 3c, and 3d is greater than the sum of the heating operation loads. Cooling-equalization operation is a cooling-dominated mixing operation in which the sum of the cooling operation loads of the multiple utilization side units 3a, 3b, 3c, and 3d is equal to the sum of the heating operation loads. Heating-dominated operation is a cooling-dominated mixing operation in which the sum of the heating operation loads of the multiple utilization side units 3a, 3b, 3c, and 3d is greater than the sum of the cooling operation loads. Full heating operation is an operation in which all the utilization side units 3a, 3b, 3c, and 3d are heated. Hereinafter, reference is made to Figure 3 to Figure 7 , the five operating actions of the air conditioning device 1a are explained. Figure 3 to Figure 7 In FIG. 1 , a thick pipe indicates a pipe through which the refrigerant flows, and a thin pipe indicates a pipe through which the refrigerant does not flow. A valve provided in a thick pipe is opened, and a valve provided in a thin pipe is closed.

[0100] Here, in the cooling operation, the cooling-main operation, the cooling-heating equalization operation, and the heating-main operation, the ejectors 41a, 41b, 41c, 41d of the intermediate units 4a, 4b, 4c, 4d can be activated, and the ejectors 41a, 41b, 41c, 41d can be inactivated. Therefore, in the cooling operation, the cooling-main operation, the cooling-heating equalization operation, and the heating-main operation, it is possible to select whether to activate the ejectors 41a, 41b, 41c, 41d or not to activate the ejectors 41a, 41b, 41c, 41d. On the other hand, in the heating operation, the ejectors 41a, 41b, 41c, 41d are inactivated.

[0101] In addition, here, the ejector 25 of the heat source side unit 2 is activated in the heating main operation and the heating only operation.

[0102] (1-3-1) Full refrigeration operation

[0103] (1-3-1-1) When the ejector is activated

[0104] like Figure 3 As shown, in full refrigeration operation, for example, the side units 3a, 3b, 3c, and 3d are all used for refrigeration operation (that is, the side heat exchangers 31a, 31b, 31c, and 31d all act as evaporators of the refrigerant and the heat source side heat exchangers 23a and 23b act as heat radiators of the refrigerant).

[0105] At this time, in the heat source side unit 2, under the action of the control unit 50, the switching mechanisms 22a and 22b are switched to connect the discharge side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b ( Figure 3 The switching mechanism 22a and 22b are switched to the state shown by the solid line of the switching mechanism 22a and 22b, so that the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b function as a heat radiator of the refrigerant. In addition, under the action of the control unit 50, the switching mechanism 22c is switched to connect the suction side of the compressor 21 and the second connecting pipe 6 ( Figure 3 The state shown by the solid line of the switching mechanism 22c of the compressor 21 is set to send the refrigerant flowing in the second connecting pipe 6 to the suction side of the compressor 21. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a and the second heat source side expansion valve 24b are set to open (here, fully open), the heat source side first valve V21 is set to open, and the heat source side second valve V22 is set to fully closed.

[0106] In the intermediate units 4a, 4b, 4c, 4d, in order to make the injectors 41a, 41b, 41c, 41d work, under the action of the control unit 50, the intermediate first valves V41a, V41b, V41c, V41d are set to be closed, the intermediate second valves V42a, V42b, V42c, V42d are set to be open, the intermediate third valves V43a, V43b, V43c, V43d are set to be closed, the intermediate fourth valves V44a, V44b, V44c, V44d are set to be open, and the intermediate sixth valves V46a, V46b, V46c, V46d are set to be open.

[0107] In the usage-side units 3a, 3b, 3c, 3d, the opening degrees of the usage-side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the refrigeration load of each usage-side unit 3a, 3b, 3c, 3d.

[0108] In this way, when the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate units 4a, 4b, 4c, 4d are controlled by the control unit 50, the refrigerant in the supercritical state ejected from the compressor 21 is sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b via the switching mechanism 22a, 22b. The refrigerant sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b is cooled by heat exchange with outdoor air in the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b, which function as a heat radiator of the refrigerant, thereby releasing heat. The above refrigerant passes through the first heat source side expansion valve 24a and the second heat source side expansion valve 24b, then merges, and further flows out of the heat source side unit 2 via the heat source side first valve V21.

[0109] The refrigerant flowing out of the heat source side unit 2 is sent to the intermediate units 4a, 4b, 4c, 4d through the first communication pipe 5. Since the intermediate first valves V41a, V41b, V41c, V41d are closed and the intermediate second valves V42a, V42b, V42c, V42d are opened, the refrigerant sent to the intermediate units 4a, 4b, 4c, 4d flows into the drive inlets 411a, 411b, 411c, 411d of the ejectors 41a, 41b, 41c, 41d. The refrigerant is mixed with the refrigerant flowing into the suction inlets 412a, 412b, 412c, 412d (the refrigerant evaporated in the utilization side heat exchangers 31a, 31b, 31c, 31d functioning as evaporators of the refrigerant) and is ejected from the ejection ports 413a, 413b, 413c, 413d. The gas-liquid two-phase refrigerant flowing out of the ejectors 41a, 41b, 41c, 41d flows into the refrigerant inlets 421a, 421b, 421c, 421d of the gas-liquid separators 42a, 42b, 42c, 42d. Then, the refrigerant separated in the gas-liquid separators 42a, 42b, 42c, 42d and flowing out of the liquid side outlets 422a, 422b, 422c, 422d flows out of the intermediate units 4a, 4b, 4c, 4d via the intermediate fifth valves V45a, V45b, V45c, V45d.

[0110] The refrigerant flowing out of the intermediate units 4a, 4b, 4c, 4d is sent to the use-side units 3a, 3b, 3c, 3d through the fourth communication pipes 8a, 8b, 8c, 8d. The refrigerant sent to the use-side units 3a, 3b, 3c, 3d is sent to the use-side heat exchangers 31a, 31b, 31c, 31d via the use-side expansion valves 32a, 32b, 32c, 32d. The refrigerant is heated by heat exchange with the indoor air supplied from the room in the use-side heat exchangers 31a, 31b, 31c, 31d, which function as evaporators of the refrigerant, and then evaporates and flows out of the use-side units 3a, 3b, 3c, 3d. On the other hand, the indoor air cooled in the use-side heat exchangers 31a, 31b, 31c, 31d is sent to the room, thereby cooling the room.

[0111] The refrigerant flowing out of the utilization side units 3a, 3b, 3c, 3d is sent to the intermediate units 4a, 4b, 4c, 4d through the fifth communication pipes 9a, 9b, 9c, 9d. Since the intermediate third valves V43a, V43b, V43c, V43d are closed and the intermediate fourth valves V44a, V44b, V44c, V44d are opened, the refrigerant sent to the intermediate units 4a, 4b, 4c, 4d flows into the suction inlets 412a, 412b, 412c, 412d of the ejectors 41a, 43b, 43c, 43d. The low-pressure refrigerant flowing into the ejectors 41a, 41b, 41c, 41d is mixed with the refrigerant flowing in from the drive inlets 411a, 411b, 411c, 411d in the ejectors 41a, 41b, 41c, 41d, thereby increasing the pressure. The two-phase refrigerant in which the pressure is increased and discharged from the discharge ports 413a, 413b, 413c, 413d flows into the refrigerant inlets 421a, 421b, 421c, 421d of the gas-liquid separators 42a, 42b, 42c, 42d. Then, the refrigerant separated in the gas-liquid separators 42a, 42b, 42c, 42d and flowing out from the gas-side outlets 423a, 423b, 423c, 423d is branched to the sixth intermediate pipes P46a, P46b, P46c, P46d and the seventh intermediate pipes P47a, P47b, P47c, P47d, and flows out from the intermediate units 4a, 4b, 4c, 4d.

[0112] The refrigerant flowing out of the sixth intermediate pipes P46a, P46b, P46c, P46d of the intermediate units 4a, 4b, 4c, 4d is sent to the heat source side unit 2 through the second communication pipe 6. The refrigerant flowing out of the seventh intermediate pipes P47a, P47b, P47c, P47d of the intermediate units 4a, 4b, 4c, 4d is sent to the heat source side unit 2 through the third communication pipe 7.

[0113] The refrigerant sent from the second communication pipe 6 to the heat source side unit 2 flows into the refrigerant inlet 26a of the gas-liquid separator 26 via the third switching mechanism 22c and the heat source side third valve V23. The refrigerant sent from the third communication pipe 7 to the heat source side unit 2 also flows into the refrigerant inlet 26a of the gas-liquid separator 26. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0114] In this way, when the above-mentioned full refrigeration operation is performed, the ejectors 41a, 41b, 41c, 41d of the intermediate units 4a, 4b, 4c, 4d are activated to increase the pressure of the refrigerant evaporated in the side units 3a, 3b, 3c, 3d used for refrigeration operation, and then return it to the compressor 21 through the second connecting pipe 6 and the third connecting pipe 7.

[0115] (1-3-1-2) Situations that make the ejector inoperative

[0116] In the intermediate units 4a, 4b, 4c, 4d, when the injectors 41a, 41b, 41c, 41d are rendered inoperative, under the action of the control unit 50, the intermediate first valves V41a, V41b, V41c, V41d are set to open, the intermediate second valves V42a, V42b, V42c, V42d are set to closed, the intermediate third valves V43a, V43b, V43c, V43d are set to open, the intermediate fourth valves V44a, V44b, V44c, V44d are set to open, and the intermediate sixth valves V46a, V46b, V46c, V46d are set to open.

[0117] In this case, since the intermediate first valves V41a, V41b, V41c, V41d are opened and the intermediate second valves V42a, V42b, V42c, V42d are closed, the refrigerant sent from the heat source side unit 2 to the intermediate units 4a, 4b, 4c, 4d does not pass through the ejectors 41a, 41b, 41c, 41d, but flows out from the intermediate first pipe P41 through the fourth connecting pipe 8a, 8b, 8c, 8d to the utilization side units 3a, 3b, 3c, 3d.

[0118] Since the intermediate third valve V43a, V43b, V43c, V43d and the intermediate fourth valve V44a, V44b, V44c, V44d are open and there is no driving flow in the ejectors 41a, 41b, 41c, 41d, the refrigerant delivered from the utilization side units 3a, 3b, 3c, 3d through the fifth connecting pipe 9a, 9b, 9c, 9d to the intermediate units 4a, 4b, 4c, 4d does not pass through the ejectors 41a, 41b, 41c, 41d, but flows out from the intermediate third pipe P43 through the second connecting pipe 6 to the heat source side unit 2.

[0119] (1-3-2) Refrigeration main operation

[0120] (1-3-2-1) When the ejector is activated

[0121] like Figure 4 As shown, in the refrigeration main operation, for example, the side units 3b, 3c, 3d are used for cooling operation and the side unit 3a is used for heating operation (that is, the side heat exchangers 31b, 31c, 31d act as evaporators of the refrigerant and the side heat exchanger 31a acts as a heat radiator of the refrigerant).

[0122] At this time, in the heat source side unit 2, under the action of the control unit 50, the switching mechanism 22a is switched to connect the discharge side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a ( Figure 4 The switching mechanism 22a is switched to the state shown by the solid line of the switching mechanism 22a, so that the first heat source side heat exchanger 23a functions as a heat radiator of the refrigerant. In addition, under the action of the control unit 50, the switching mechanism 22c is switched to connect the discharge side of the compressor 21 with the second communication pipe 6 ( Figure 4 The switching mechanism 22c of the compressor 21 is in the state shown by the solid line) to send the refrigerant ejected from the compressor 21 to the second communication pipe 6. In addition, here, since the refrigerant does not flow in the switching mechanism 22b, the switching mechanism 22b is not controlled by the control unit 50. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to open, the second heat source side expansion valve 24b is set from slightly open to fully closed, the heat source side first valve V21 is set to open, and the heat source side second valve V22 is set to fully closed.

[0123] In the intermediate unit 4a, the intermediate first valve V41a is opened, the intermediate second valve V42a is fully closed, the intermediate third valve V43a is opened, the intermediate fourth valve V44a is closed, and the intermediate sixth valve V46a is closed under the action of the control unit 50. In the intermediate units 4b, 4c, and 4d, in order to make the injectors 41b, 41c, and 41d function, the intermediate first valves V41b, V41c, and V41d are closed, the intermediate second valves V42b, V42c, and V42d are opened, the intermediate third valves V43b, V43c, and V43d are closed, the intermediate fourth valves V44b, V44c, and V44d are opened, and the intermediate sixth valves V46b, V46c, and V46d are closed.

[0124] In the utilization side units 3a, 3b, 3c, 3d, the opening degrees of the utilization side expansion valves 32a, 32b, 32c, 32d are adjusted according to the heating load of the utilization side unit 3a and the cooling load of the utilization side units 3b, 3c, 3d under the control of the control unit 50.

[0125] In this way, when the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate units 4a, 4b, 4c, 4d are controlled by the control unit 50, a part of the supercritical refrigerant ejected from the compressor 21 is sent to the first heat source side heat exchanger 23a through the first switching mechanism 22a, and the remaining part flows out from the heat source side unit 2 to the second communication pipe 6 through the third switching mechanism 22c. The refrigerant sent to the first heat source side heat exchanger 23a exchanges heat with the outdoor air in the first heat source side heat exchanger 23a, which functions as a heat radiator of the refrigerant, and is cooled to release heat. The refrigerant flows out from the heat source side unit 2 to the first communication pipe 5 via the first heat source side expansion valve 24a and the heat source side first valve V21.

[0126] The refrigerant flowing out of the second communication pipe 6 is sent to the intermediate unit 4a through the branch pipe portion 6a. The high-pressure refrigerant sent to the intermediate unit 4a flows into the intermediate third pipe 43a and flows out of the intermediate unit 4a through the intermediate third valve V43a.

[0127] The refrigerant flowing out of the intermediate unit 4a is sent to the utilization side unit 3a through the fifth connecting pipe 9a. The refrigerant sent to the utilization side unit 3a is sent to the utilization side heat exchanger 31a. The high-pressure refrigerant sent to the utilization side heat exchanger 31a is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchanger 31a, which functions as a heat releaser of the refrigerant, thereby releasing heat. The above-mentioned refrigerant flows out of the utilization side unit 3a through the utilization side expansion valve 32a set to be fully opened. On the other hand, the indoor air heated in the utilization side heat exchanger 31a is sent to the room, thereby heating the room.

[0128] The refrigerant flowing out of the usage side unit 3a is sent to the intermediate unit 4a through the fourth communication pipe 8a. The refrigerant sent to the intermediate unit 4a flows into the first intermediate pipe 41a and flows out of the intermediate unit 4a through the first intermediate valve V41a.

[0129] The refrigerant flowing out of the intermediate unit 4a passes through the branch pipe portion 5a and merges with the refrigerant flowing out of the first heat source side heat exchanger 23a to the first communication pipe 5 at the confluence portion of the first communication pipe 5. The merged refrigerant passes through the branch pipe portions 5b, 5c, 5d and is sent to the intermediate units 4b, 4c, 4d.

[0130] The refrigerant sent to the intermediate units 4b, 4c, 4d flows into the driving inlet 411b, 411c, 411d of the ejectors 41b, 41c, 41d through the intermediate first pipes P41b, P41c, P41d and the intermediate second pipes P42b, P42c, P42d. The refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 412b, 412c, 412d, and ejected from the ejection outlet 413b, 413c, 413d. The refrigerant in the gas-liquid two-phase state flowing out of the ejectors 41b, 41c, 41d flows into the refrigerant inlet 421b, 421c, 421d of the gas-liquid separators 42b, 42c, 42d. Next, the refrigerant separated in the gas-liquid separators 42b, 42c, 42d and flowing out from the liquid-side outlets 422b, 422c, 422d flows out from the intermediate units 4b, 4c, 4d via the fifth intermediate valves V45b, V45c, V45d.

[0131] The refrigerant flowing out of the intermediate units 4b, 4c, 4d is sent to the use-side units 3b, 3c, 3d through the fourth communication pipes 8b, 8c, 8d. The refrigerant sent to the use-side units 3b, 3c, 3d is sent to the use-side heat exchangers 31b, 31c, 31d via the use-side expansion valves 32b, 32c, 32d. The refrigerant sent to the use-side heat exchangers 31b, 31c, 31d is heated by heat exchange with the indoor air supplied from the room in the use-side heat exchangers 31b, 31c, 31d, which function as evaporators of the refrigerant, and evaporates. The refrigerant flows out of the use-side units 3b, 3c, 3d. On the other hand, the indoor air cooled in the use-side heat exchangers 31b, 31c, 31d is sent to the room, thereby cooling the room.

[0132] The refrigerant flowing out of the utilization side units 3b, 3c, 3d is sent to the intermediate units 4b, 4c, 4d through the fifth communication pipes 9b, 9c, 9d. The refrigerant sent to the intermediate units 4b, 4c, 4d flows into the suction inlet 412b, 412c, 412d of the ejectors 41b, 41c, 41d. The low-pressure refrigerant flowing into the ejectors 41b, 41c, 41d is mixed with the refrigerant flowing in from the drive inlet 411b, 411c, 411d in the ejectors 41b, 41c, 41d, thereby increasing the pressure. The refrigerant in the two-phase state that is pressurized and ejected flows into the refrigerant inlet 421b, 421c, 421d of the gas-liquid separators 42b, 42c, 42d. Next, the refrigerant separated in the gas-liquid separators 42b, 42c, 42d and flowing out from the gas-side outlets 423b, 423c, 423d passes through the seventh intermediate pipes P47b, P47c, P47d and flows out from the intermediate units 4b, 4c, 4d.

[0133] The refrigerant flowing out of the intermediate units 4 b , 4 c , and 4 d is sent to the heat source side unit 2 through the branch pipe portions 7 b , 7 c , and 7 d of the third communication pipe 7 .

[0134] The refrigerant sent to the heat source side unit 2 flows into the refrigerant inlet 26a of the gas-liquid separator 26. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0135] Thus, when the cooling main operation is performed, the ejectors 41a, 41b, 41c, 41d of the intermediate units 4b, 4c, 4d are activated to increase the pressure of the refrigerant evaporated in the utilization side units 3b, 3c, 3d performing the cooling operation, and then return to the compressor 21 through the third communication pipe 7. In addition, the refrigerant after releasing heat in the utilization side unit 3a performing the heating operation is not pressurized in the ejector 41a.

[0136] (1-3-2-2) Situations that make the ejector inoperative

[0137] In the intermediate units 4b, 4c, 4d, when the injectors 41b, 41c, 41d are rendered inoperative, under the action of the control unit 50, the intermediate first valve V41b, V41c, V41d is set to open, the intermediate second valve V42b, V42c, V42d is set to closed, the intermediate third valve V43b, V43c, V43d is set to closed, the intermediate fourth valve V44b, V44c, V44d is set to open, and the intermediate sixth valve V46b, V46c, V46d is set to closed.

[0138] In this case, the refrigerant sent from the heat source side unit 2 to the intermediate unit 4b, 4c, 4d does not pass through the ejectors 41b, 41c, 41d, but flows out from the intermediate first pipe P41 through the fourth communication pipe 8b, 8c, 8d to the use side unit 3b, 3c, 3d. The refrigerant sent from the use side unit 3b, 3c, 3d to the intermediate unit 4b, 4c, 4d does not pass through the ejectors 41b, 41c, 41d, but flows out from the intermediate third pipe P43 through the intermediate fourth valve V44b, V44c, V44d and the check valve, and flows out from the intermediate seventh pipe P47b, 47c, 47d. The refrigerant flowing out from the intermediate unit 4b, 4c, 4d flows into the heat source side unit 2 through the third communication pipe 7.

[0139] (1-3-3)Equal operation of hot and cold

[0140] (1-3-3-1) When the ejector is activated

[0141] like Figure 5 As shown, in the hot and cold equal operation, for example, the side units 3c and 3d are used for cooling operation and the side units 3a and 3b are used for heating operation (that is, the side heat exchangers 31c and 31d act as evaporators of the refrigerant and the side heat exchangers 31a and 31b act as radiators of the refrigerant).

[0142] At this time, in the heat source side unit 2, under the action of the control unit 50, the first switching mechanism 22a is switched to connect the discharge side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a ( Figure 5 In addition, under the action of the control unit 50, the second switching mechanism 22b is switched to connect the suction side of the compressor 21 and the gas side of the second heat source side heat exchanger 23b ( Figure 5In addition, under the action of the control unit 50, the third switching mechanism 22c is switched to connect the discharge side of the compressor 21 and the second communication pipe 6 ( Figure 5 The state shown by the solid line of the switching mechanism 22c of the compressor 21 is set to send the refrigerant ejected from the compressor 21 to the second connecting pipe 6. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to open, the second heat source side expansion valve 24b is set from slightly open to fully closed, the heat source side first valve V21 is set to open, and the heat source side second valve V22 is set to fully closed.

[0143] In the intermediate units 4a and 4b, the first intermediate valves V41a and V41b are opened, the second intermediate valves V42a and V42b are fully closed, the third intermediate valves V43a and V43b are opened, the fourth intermediate valves V44a and V44b are closed, and the sixth intermediate valves V46a and V46b are closed under the action of the control unit 50. In the intermediate units 4c and 4d, in order to make the injectors 41c and 41d work, the first intermediate valves V41c and V41d are closed, the second intermediate valves V42c and V42d are opened, the third intermediate valves V43c and V43d are closed, the fourth intermediate valves V44c and V44d are opened, and the sixth intermediate valves V46c and V46d are closed.

[0144] In the utilization side units 3a, 3b, 3c, 3d, the opening degrees of the utilization side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the heating load of the utilization side units 3a, 3b and the cooling load of the utilization side units 3c, 3d.

[0145] In this way, the control unit 50 controls the components of the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate units 4a, 4b, 4c, 4d. First, the case where the sum of the cooling operation loads of the utilization side units 3c, 3d is equal to the sum of the heating operation loads of the utilization side units 3a, 3b is described.

[0146] Part of the supercritical refrigerant discharged from the compressor 21 is sent to the first heat source side heat exchanger 23a through the first switching mechanism 22a, and the remaining part flows out of the heat source side unit 2 to the second communication pipe 6 through the third switching mechanism 22c.

[0147] The refrigerant sent to the first heat source side heat exchanger 23a exchanges heat with the outdoor air in the first heat source side heat exchanger 23a, which functions as a heat radiator of the refrigerant, and is cooled, thereby releasing heat. Then, the refrigerant is sent from the first heat source side heat exchanger 23a to the second heat source side heat exchanger 23b via the first heat source side expansion valve 24a and the second heat source side expansion valve 24b. The refrigerant sent to the second heat source side heat exchanger 23b passes through the gas-liquid separator 26 via the second switching mechanism 22b and the heat source side third valve V23, and returns to the compressor 21.

[0148] The refrigerant flowing out of the second communication pipe 6 is sent to the intermediate units 4a and 4b through the branch pipes 6a and 6b. The high-pressure refrigerant sent to the intermediate units 4a and 4b flows into the intermediate third pipes P43a and P43b, and flows out of the intermediate units 4a and 4b through the intermediate third valves V43a and V43b.

[0149] The refrigerant flowing out from the intermediate units 4a and 4b is sent to the utilization side units 3a and 3b through the fifth connecting pipes 9a and 9b. The refrigerant sent to the utilization side units 3a and 3b is sent to the utilization side heat exchangers 31a and 31b. The high-pressure refrigerant sent to the utilization side heat exchangers 31a and 31b is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31a and 31b, which function as heat radiators of the refrigerant, thereby releasing heat. The above-mentioned refrigerant flows out from the utilization side units 3a and 3b through the utilization side expansion valves 32a and 32b set to be fully opened. On the other hand, the indoor air heated in the utilization side heat exchangers 31a and 31b is sent to the room, thereby heating the room.

[0150] The refrigerant flowing out of the utilization side units 3a and 3b is sent to the intermediate units 4a and 4b through the fourth communication pipes 8a and 8b. The refrigerant sent to the intermediate units 4a and 4b flows into the intermediate first pipes P41a and P41b, and flows out of the intermediate units 4a and 4b through the intermediate first valves V41a and V41b.

[0151] The refrigerant flowing out of the intermediate units 4a and 4b flows in the branch pipes 5a and 5b, flows to the branch pipes 5c and 5d through the confluence of the first connecting pipe 5, and is sent to the intermediate units 4c and 4d. The refrigerant sent to the intermediate units 4c and 4d flows into the drive inlet 411c and 411d of the ejectors 41c and 41d. The above refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 412c and 412d, and is ejected from the ejection outlet 413c and 413d. The refrigerant in the gas-liquid two-phase state flowing out of the ejectors 41c and 41d flows into the refrigerant inlet 421c and 421d of the gas-liquid separator 42c and 42d. Next, the refrigerant separated in the gas-liquid separators 42c and 42d and flowing out from the liquid-side outlets 422c and 422d flows out from the intermediate units 4b, 4c, and 4d via the fifth intermediate valves V45c and V45d.

[0152] The refrigerant flowing out of the intermediate units 4c and 4d is sent to the utilization side units 3c and 3d through the fourth connecting pipes 8c and 8d. The refrigerant sent to the utilization side units 3c and 3d is sent to the utilization side heat exchangers 31c and 31d via the utilization side expansion valves 32c and 32d. The refrigerant sent to the utilization side heat exchangers 31c and 31d is heated by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31c and 31d, which function as evaporators of the refrigerant, and evaporates. The above-mentioned refrigerant flows out of the utilization side units 3c and 3d. On the other hand, the indoor air cooled in the utilization side heat exchangers 31c and 31d is sent to the room, thereby cooling the room.

[0153] The refrigerant flowing out of the utilization side units 3c and 3d is sent to the intermediate units 4c and 4d through the fifth connecting pipes 9c and 9d. The refrigerant sent to the intermediate units 4c and 4d flows into the suction inlet 412c and 412d of the ejectors 41c and 41d. The low-pressure refrigerant flowing into the ejectors 41c and 41d is mixed with the refrigerant flowing in from the driving inlet 411c and 411d in the ejectors 41c and 41d, thereby increasing the pressure. The refrigerant in the two-phase state that is pressurized and ejected flows into the refrigerant inlet 421c and 421d of the gas-liquid separator 42c and 42d. Then, the refrigerant separated in the gas-liquid separator 42c and 42d and flowing out from the gas side outlet 423c and 423d flows out of the intermediate units 4c and 4d through the seventh intermediate pipes P47c and P47d.

[0154] The refrigerant flowing out of the intermediate units 4 c and 4 d is sent to the heat source side unit 2 through the branch pipe portions 7 c and 7 d of the third communication pipe 7 .

[0155] The refrigerant sent to the heat source side unit 2 flows into the refrigerant inlet 26a of the gas-liquid separator 26. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0156] Next, a case where the sum of the cooling operation loads of the usage-side units 3 c and 3 d increases compared to the sum of the heating operation loads of the usage-side units 3 a and 3 b will be described.

[0157] In the heat source side unit 2, the refrigerant that is sent to the first heat source side heat exchanger 23a that functions as a heat radiator of the refrigerant and releases heat flows out of the heat source side unit 2 via the first heat source side expansion valve 24a and the heat source side first valve V21, and flows to the first communication pipe 5. Then, the refrigerant is merged with the refrigerant (refrigerant that has undergone heat exchange in the utilization side heat exchangers 31a and 31b) that has flowed out from the intermediate units 4a and 4b to the branch pipe parts 5a and 5b at the confluence portion of the first communication pipe 5. The merged refrigerant is sent to the intermediate units 4c and 4d via the branch pipe parts 5c and 5d.

[0158] Next, a case where the sum of the heating operation loads of the usage-side units 3 a and 3 b increases compared to the sum of the cooling operation loads of the usage-side units 3 c and 3 d will be described.

[0159] The refrigerant that has undergone heat exchange in the utilization side heat exchangers 31a and 31b and further flows out of the intermediate units 4a and 4b flows in the branch pipes 5a and 5b, and at the confluence of the first communication pipe 5, a part of it flows to the heat source side unit 2, and the rest flows to the branch pipes 5c and 5d, and is sent to the intermediate units 4c and 4d. The refrigerant that has flowed to the heat source side unit 2 flows in the first heat source side pipe P21, and is sent to the second heat source side heat exchanger 23b via the first heat source side valve V21 and the second heat source side expansion valve 24b. The refrigerant evaporated in the second heat source side heat exchanger 23b flows into the refrigerant inlet 26a of the gas-liquid separator 26 via the second switching mechanism 22b and the third heat source side valve V23. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0160] Thus, when performing the above-mentioned cooling and heating equalization operation, the ejectors 41c and 41d of the intermediate units 4c and 4d are activated to increase the pressure of the refrigerant evaporated in the utilization side units 3c and 3d performing the cooling operation, and then return it to the compressor 21 through the third communication pipe 7. In addition, the refrigerant that releases heat in the utilization side units 3a and 3b performing the heating operation is not pressurized in the ejectors 41a and 41b.

[0161] (1-3-3-2) Situations that make the ejector inoperative

[0162] In the intermediate units 4c and 4d, when the ejectors 41c and 41d are disabled, the first intermediate valves V41c and V41d are opened, the second intermediate valves V42c and V42d are closed, the third intermediate valves V43c and V43d are closed, the fourth intermediate valves V44c and V44d are opened, and the sixth intermediate valves V46c and V46d are closed under the control of the control unit 50. The operation in this case is the same as that of the intermediate units 4c and 4d in the cooling main operation.

[0163] (1-3-4) Heating main operation

[0164] (1-3-4-1) When the ejector is activated

[0165] like Figure 6 As shown, in the main heating operation, for example, the side unit 3d is used for cooling operation and the side units 3a, 3b, 3c are used for heating operation (that is, the side heat exchanger 31d acts as an evaporator of the refrigerant and the side heat exchangers 31a, 31b, 31c act as radiators of the refrigerant).

[0166] At this time, in the heat source side unit 2, under the action of the control unit 50, the first switching mechanism 22a and the second switching mechanism 22b are switched to connect the suction side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b ( Figure 6 The first switching mechanism 22a and the second switching mechanism 22b are switched to the state shown by the solid line of the first switching mechanism 22a and 22b, so that the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b function as evaporators of the refrigerant. In addition, under the action of the control unit 50, the switching mechanism 22c is switched to connect the discharge side of the compressor 21 and the second connecting pipe 6 ( Figure 6 The state shown by the solid line of the switching mechanism 22c is to deliver the refrigerant ejected from the compressor 21 to the second connecting pipe 6. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to open, the second heat source side expansion valve 24b is set to open, the heat source side first valve V21 is set to close, and the heat source side second valve V22 is set to open.

[0167] In the intermediate units 4a, 4b, 4c, the first intermediate valves V41a, V41b, V41c are opened, the second intermediate valves V42a, V42b, V42c are fully closed, the third intermediate valves V43a, V43b, V43c are opened, the fourth intermediate valves V44a, V44b, V44c are closed, and the sixth intermediate valves V46a, V46b, V46c are closed under the control of the control unit 50. In the intermediate unit 4d, in order to activate the injector 41d, the first intermediate valve V41d is closed, the second intermediate valve V42d is opened, the third intermediate valve V43d is closed, the fourth intermediate valve V44d is opened, and the sixth intermediate valve V46d is closed under the control of the control unit 50.

[0168] In the utilization side units 3a, 3b, 3c, 3d, the opening degrees of the utilization side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the heating load of the utilization side units 3a, 3b, 3c and the cooling load of the utilization side unit 3d.

[0169] In this way, when the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d and the intermediate units 4a, 4b, 4c, 4d are controlled by the control unit 50, the supercritical refrigerant ejected from the compressor 21 flows out from the heat source side unit 2 to the second connecting pipe 6 through the third switching mechanism 22c.

[0170] The refrigerant flowing out of the second communication pipe 6 is sent to the intermediate units 4a, 4b, 4c through the branch pipes 6a, 6b, 6c. The high-pressure refrigerant sent to the intermediate units 4a, 4b, 4c flows into the intermediate third pipes P43a, P43b, P43c, and flows out of the intermediate units 4a, 4b, 4c through the intermediate third valves V43a, V43b, V43c.

[0171] The refrigerant flowing out of the intermediate units 4a, 4b, 4c is sent to the utilization side units 3a, 3b, 3c through the fifth communication pipes 9a, 9b, 9c. Then, the high-pressure refrigerant sent to the utilization side heat exchangers 31a, 31b, 31c is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31a, 31b, 31c, which function as heat radiators of the refrigerant, thereby releasing heat. The refrigerant flows out of the utilization side units 3a, 3b, 3c through the utilization side expansion valves 32a, 32b, 32c. On the other hand, the indoor air heated in the utilization side heat exchanger 31a is sent to the room, thereby heating the room.

[0172] The refrigerant flowing out of the utilization side units 3a, 3b, 3c is sent to the intermediate units 4a, 4b, 4c through the fourth communication pipes 8a, 8b, 8c. The refrigerant sent to the intermediate units 4a, 4b, 4c flows into the intermediate first pipes P41a, P41b, P41c, and flows out of the intermediate units 4a, 4b, 4c through the intermediate first valves V41a, V41b, V41c.

[0173] The refrigerant flowing out of the intermediate units 4a, 4b, 4c passes through the branch pipe portions 5a, 5b, 5c, and at the confluence portion of the first communication pipe 5, a portion flows into the heat source side unit 2, and the rest flows into the branch pipe portion 5d.

[0174] The refrigerant flowing into the branch pipe portion 5d is sent to the intermediate unit 4d. The refrigerant sent to the intermediate unit 4d flows into the drive inlet 411d of the ejector 41d. The above refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 412d and ejected from the ejection port 413d. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 41d flows into the refrigerant inlet 421d of the gas-liquid separator 42d. Then, the refrigerant separated in the gas-liquid separator 42d and flowing out from the liquid side outlet 422d flows out of the intermediate unit 4d via the intermediate fifth valve V45d.

[0175] The refrigerant flowing out of the intermediate unit 4d is sent to the use-side unit 3d through the fourth communication pipe 8d. The refrigerant sent to the use-side unit 3d is sent to the use-side heat exchanger 31d, which functions as an evaporator of the refrigerant, via the use-side expansion valve 32d, and is heated by heat exchange with the indoor air supplied from the room, thereby evaporating. The refrigerant flows out of the use-side unit 3d. On the other hand, the indoor air cooled in the use-side heat exchanger 31d is sent to the room, thereby cooling the room.

[0176] The refrigerant flowing out of the utilization side unit 3d is sent to the intermediate unit 4d through the fifth communication pipe 9d. The refrigerant sent to the intermediate unit 4d flows into the suction inlet 412d of the ejector 41d, and is mixed with the refrigerant flowing in from the driving inlet 411d in the ejector 41d, thereby increasing the pressure. The refrigerant in the two-phase state that is increased in pressure and ejected flows into the refrigerant inlet 421d of the gas-liquid separator 42d. Then, the refrigerant separated in the gas-liquid separator 42d and flowing out from the gas side outlet 423d flows out of the intermediate unit 4d through the seventh intermediate pipe P47d.

[0177] The refrigerant flowing out of the intermediate unit 4d is sent to the heat source side unit 2 through the branch pipe portion 7d of the third communication pipe 7. The refrigerant flows into the refrigerant inlet 26a of the gas-liquid separator 26.

[0178] Furthermore, at the confluence portion of the first communication pipe 5, the refrigerant flowing into the heat source side unit 2 (a part of the refrigerant after heat exchange in the utilization side heat exchangers 31a, 31b, 31c) flows into the driving inlet 25a of the ejector 25. The above refrigerant is mixed with the refrigerant flowing in from the suction inlet 25b (the refrigerant evaporated in the heat source side heat exchangers 23a, 23b functioning as evaporators of the refrigerant) and ejected from the ejection port 25c. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 25 flows into the refrigerant inlet 26d of the gas-liquid separator 26d.

[0179] In this way, the refrigerant from the intermediate units 4a, 4b, and 4c and the refrigerant from the intermediate unit 4d converge in the gas-liquid separator 26. Next, the refrigerant separated in the gas-liquid separator 26 and flowing out from the liquid side outlet 26b is branched to flow to the first heat source side expansion valve 24a and the second heat source side expansion valve 24b through the heat source side fourth valve V24, and is sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b. The refrigerant sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b is heated by heat exchange with outdoor air in the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b acting as evaporators of the refrigerant, thereby evaporating. Each evaporated refrigerant flows into the suction inlet 25b of the ejector 25 through the first switching mechanism 22a and the second switching mechanism 22b. The low-pressure refrigerant is mixed with the refrigerant flowing in from the driving inlet 25 a in the ejector 41 d , thereby increasing its pressure. The two-phase refrigerant in increased pressure and ejected flows into the refrigerant inlet 26 a of the gas-liquid separator 26 .

[0180] Next, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas-side outlet 26 c is sucked into the compressor 21 .

[0181] Thus, when the above-mentioned heating main operation is performed, the ejector 41d of the intermediate unit 4d is activated to increase the pressure of the refrigerant evaporated in the utilization side unit 3d performing the cooling operation, and then return it to the compressor 21 through the third communication pipe 7. In addition, the refrigerant that releases heat in the utilization side units 3a, 3b, and 3c performing the heating operation is not pressurized in the ejectors 41a, 41b, and 41c.

[0182] (1-3-4-2) Situations that make the ejector inoperative

[0183] In the intermediate unit 4d, when the ejector 41d is disabled, the intermediate first valve V41d is opened, the intermediate second valve V42d is closed, the intermediate third valve V43d is closed, the intermediate fourth valve V44d is opened, and the intermediate sixth valve V46d is closed under the control of the control unit 50. The operation in this case is the same as that of the intermediate unit 4d in the cooling main operation.

[0184] (1-3-5) Full heating operation

[0185] like Figure 7 As shown, in full heating operation, for example, all the side units 3a, 3b, 3c, and 3d are used for heating operation (that is, all the side heat exchangers 31a, 31b, 31c, and 31d act as heat radiators of the refrigerant and the heat source side heat exchangers 23a and 23b act as evaporators of the refrigerant).

[0186] At this time, in the heat source side unit 2, under the action of the control unit 50, the first switching mechanism 22a and the second switching mechanism 22b are switched to connect the suction side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b ( Figure 7 The switching mechanism 22a and 22b are switched to the state shown by the solid line of the switching mechanism 22a and 22b, so that the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b function as evaporators of the refrigerant. In addition, under the action of the control unit 50, the third switching mechanism 22c is switched to connect the discharge side of the compressor 21 and the second communication pipe 6 ( Figure 7 The state shown by the solid line of the switching mechanism 22c is to deliver the refrigerant ejected from the compressor 21 to the second connecting pipe 6. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to open, the second heat source side expansion valve 24b is set to open, the heat source side first valve V21 is set to close, and the heat source side second valve V22 is set to open.

[0187] In the intermediate units 4a, 4b, 4c, 4d, under the action of the control unit 50, the intermediate first valves V41a, V41b, V41c, V41d are set to open, the intermediate second valves V42a, V42b, V42c, V42d are set to fully closed, the intermediate third valves V43a, V43b, V43c, V43d are set to open, the intermediate fourth valves V44a, V44b, V44c, V44d are set to closed, and the intermediate sixth valves V46a, V46b, V46c, V46d are set to closed.

[0188] In the usage-side units 3a, 3b, 3c, 3d, the opening degrees of the usage-side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the heating load of each usage-side unit 3a, 3b, 3c, 3d.

[0189] In this way, when the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d and the intermediate units 4a, 4b, 4c, 4d are controlled by the control unit 50, the supercritical refrigerant ejected from the compressor 21 flows out from the heat source side unit 2 to the second connecting pipe 6 through the third switching mechanism 22c.

[0190] The refrigerant flowing out of the second communication pipe 6 is sent to the intermediate units 4a, 4b, 4c, 4d through the branch pipes 6a, 6b, 6c, 6d. The high-pressure refrigerant sent to the intermediate units 4a, 4b, 4c, 4d flows into the intermediate third pipes P43a, P43b, P43c, P43d, and flows out of the intermediate units 4a, 4b, 4c, 4d through the intermediate third valves V43a, V43b, V43c, V43d.

[0191] The refrigerant flowing out of the intermediate units 4a, 4b, 4c, 4d is sent to the utilization side units 3a, 3b, 3c, 3d through the fifth communication pipes 9a, 9b, 9c, 9d. Then, the high-pressure refrigerant sent to the utilization side heat exchangers 31a, 31b, 31c, 31d is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31a, 31b, 31c, 31d, which function as heat radiators of the refrigerant, thereby releasing heat. The refrigerant flows out of the utilization side units 3a, 3b, 3c, 3d through the utilization side expansion valves 32a, 32b, 32c, 32d. On the other hand, the indoor air heated in the utilization side heat exchangers 31a, 31b, 31c, 31d is sent to the room, thereby heating the room.

[0192] The refrigerant flowing out of the utilization side units 3a, 3b, 3c, 3d is sent to the intermediate units 4a, 4b, 4c, 4d through the fourth communication pipes 8a, 8b, 8c, 8d. The refrigerant sent to the intermediate units 4a, 4b, 4c, 4d flows into the intermediate first pipes P41a, P41b, P41c, P41d, and flows out of the intermediate units 4a, 4b, 4c, 4d through the intermediate first valves V41a, V41b, V41c, V41d.

[0193] The refrigerant flowing out of the intermediate units 4a, 4b, 4c, and 4d converges at the confluence portion of the first communication pipe 5 through the branch pipe portions 5a, 5b, 5c, and 5d, and flows into the heat source side unit 2. The refrigerant flowing into the heat source side unit 2 flows into the drive inlet 25a of the ejector 25. The above refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 25b and ejected from the ejection port 25c. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 25 flows into the refrigerant inlet 26a of the gas-liquid separator 26. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the liquid side outlet 26b is branched through the heat source side fourth valve V24 to flow to the first heat source side expansion valve 24a and the second heat source side expansion valve 24b, and is sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b. The refrigerant sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b is heated by heat exchange with outdoor air in the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b acting as evaporators of the refrigerant, thereby evaporating. The evaporated refrigerant converges through the first switching mechanism 22a and the second switching mechanism 22b and flows into the suction inlet 25b of the ejector 25. The low-pressure refrigerant is mixed with the refrigerant flowing in from the drive inlet 25a in the ejector 25, thereby increasing the pressure. The refrigerant in the two-phase state that is pressurized and ejected flows into the refrigerant inlet 26a of the gas-liquid separator 26. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0194] Thus, when performing the above-mentioned full heating operation, the ejectors 41a, 41b, 41c, 41d of the intermediate units 4a, 4b, 4c, 4d are made inoperative. In other words, the refrigerant after releasing heat in the utilization side units 3a, 3b, 3c, 3d performing the heating operation is configured not to be pressurized in the ejectors 41a, 41b, 41c, 41d.

[0195] (1-4) Features

[0196] The air conditioning device 1a of this embodiment includes a heat source side unit 2, a plurality of use side units 3a, 3b, 3c, 3d, an intermediate unit 4a, 4b, 4c, 4d, and three or more communication pipes 5, 6, 7. The heat source side unit 2 has a compressor 21 and a heat source side heat exchanger 23a, 23b. The plurality of use side units 3a, 3b, 3c, 3d have use side heat exchangers 31a, 31b, 31c, 31d. The intermediate units 4a, 4b, 4c, 4d are switched so that the plurality of use side heat exchangers 31a, 31b, 31c, 31d individually function as an evaporator or a radiator of the refrigerant. The three or more communication pipes 5, 6, 7 connect the heat source side unit 2 and the intermediate units 4a, 4b, 4c, 4d. The intermediate units 4a, 4b, 4c, 4d include ejectors 41a, 41b, 41c, 41d and gas-liquid separators 42a, 42b, 42c, 42d. The ejectors 41a, 41b, 41c, 41d increase the pressure of the refrigerant. The refrigerant flowing out of the ejectors 41a, 41b, 41c, 41d flows into the gas-liquid separators 42a, 42b, 42c, 42d. The refrigerant after dissipating heat in the utilization side units 3a, 3b, 3c, 3d performing the heating operation is configured not to be pressurized in the ejectors 41a, 41b, 41c, 41d.

[0197] In the air conditioning device 1a of the present embodiment, the intermediate units 4a, 4b, 4c, 4d have ejectors 41a, 41b, 41c, 41d for recovering power. In addition, the refrigerant after releasing heat in the use-side units 3a, 3b, 3c, 3d performing heating operation is configured not to be pressurized in the ejectors 41a, 41b, 41c, 41d. Therefore, the ejectors 41a, 41b, 41c, 41d are made inoperative for the use-side heat exchangers 31a, 31b, 31c, 31d performing heating operation with relatively small benefits, and the refrigerant after heat exchange in the use-side heat exchangers 31a, 31b, 31c, 31d performing operation with relatively large benefits can be pressurized by the ejectors 41a, 41b, 41c, 41d. Therefore, power can be recovered by using the ejectors 41a, 41b, 41c, and 41d of the intermediate units 4a, 4b, 4c, and 4d.

[0198] Here, the air conditioner 1a is configured such that the refrigerant evaporated in the utilization side units 3a, 3b, 3c, 3d performing cooling operation flows through the ejectors 41a, 41b, 41c, 41d. Thus, the refrigerant evaporated in the utilization side heat exchangers 31a, 31b, 31c, 31d performing cooling operation with relatively greater benefits can be pressurized by the ejectors 41a, 41b, 41c, 41d. Therefore, the air conditioner 1a that recovers power can be realized.

[0199] Here, the intermediate units 4a, 4b, 4c, 4d further include intermediate first pipes P41a, P41b, P41c, P41d, intermediate first valves V41a, V41b, V41c, V41d, intermediate second pipes P42a, P42b, P42c, P42d, and intermediate second valves V42a, V42b, V42c, V42d. The intermediate first pipes P41a, P41b, P41c, P41d are pipes for allowing the refrigerant to flow between the heat source side heat exchangers 23a, 23b and the utilization side heat exchangers 31a, 31b, 31c, 31d. The intermediate first valves V41a, V41b, V41c, V41d are provided in the intermediate first pipes P41a, P41b, P41c, P41d. The intermediate second pipes P42a, P42b, P42c, and P42d are pipes branched from the intermediate first pipes P41a, P41b, P41c, and P41d between the heat source side heat exchangers 23a, 23b and the intermediate first valves V41a, V41b, V41c, and V41d, and are used to allow the refrigerant to flow to the drive inlets 411a, 411b, 411c, and 411d of the ejectors 41a, 41b, 41c, and 41d. The intermediate second valves V42a, V42b, V42c, and V42d are provided on the intermediate second pipes P42a, P42b, P42c, and P42d. The air conditioning device 1 a further includes a control unit 50 that controls the first intermediate valves V41 a , V41 b , V41 c , and V41 d and the second intermediate valves V42 a , V42 b , V42 c , and V42 d .

[0200] By utilizing the control unit 50 to open the intermediate first valves V41a, V41b, V41c, and V41d and to close the intermediate second valves V42a, V42b, V42c, and V42d, the refrigerant flowing in the utilization side heat exchangers 31a, 31b, 31c, and 31d can be supplied to the utilization side heat exchangers 31a, 31b, 31c, and 31d through the intermediate first pipes P41a, P41b, P41c, and P41d without passing through the ejectors 41a, 41b, 41c, and 41d. In addition, by using the control unit 50 to set the intermediate first valve V41a, V41b, V41c, V41d to be closed and the intermediate second valve V42a, V42b, V42c, V42d to be open, the refrigerant flowing in the utilization side heat exchanger 31a, 31b, 31c, 31d can be supplied to the heat source side heat exchanger 23a, 23b in a state of being pressurized in the ejector 41a, 41b, 41c, 41d through the intermediate second piping P42a, P42b, P42c, P42d, the ejectors 41a, 41b, 41c, 41d and the gas-liquid separators 42a, 42b, 42c, 42d. In this way, it is possible to select whether to allow the driving flow to flow to the injectors 41a, 41b, 41c, 41d by the first intermediate valves V41a, V41b, V41c, V41d and the second intermediate valves V42a, V42b, V42c, V42d. Therefore, it is possible to select whether to enable the injectors 41a, 41b, 41c, 41d or to disable the injectors 41a, 41b, 41c, 41d.

[0201] Here, the intermediate units 4a, 4b, 4c, 4d have a plurality of ejectors 41a, 41b, 41c, 41d. Each ejector 41a, 41b, 41c, 41d is connected to each of the use-side units 3a, 3b, 3c, 3d. In this way, the air conditioning device 1a of this embodiment is also applicable to a refrigerant circuit in which each ejector 41a, 41b, 41c, 41d can increase the pressure of the refrigerant in each of the use-side units 3a, 3b, 3c, 3d.

[0202] Here, the compressor 21 ejects the refrigerant in a supercritical state. As a result, since the refrigerant in a supercritical state flows in a part of the intermediate units 4a, 4b, 4c, and 4d, the refrigerant in a supercritical state can be used for the driving flow. Therefore, the effect of using the ejectors 41a, 41b, 41c, and 41d can be improved.

[0203] Here, the refrigerant compressed by the compressor 21 includes carbon dioxide. The refrigerant including carbon dioxide can be in a supercritical state. Therefore, it is possible to easily realize the air conditioning apparatus 1a in which the effect of using the ejectors 41a, 41b, 41c, and 41d is enhanced.

[0204] (2) Second Embodiment

[0205] (2-1) Overall structure

[0206] like Figure 8 As shown, the air conditioning device 1b of the second embodiment has a structure basically the same as that of the air conditioning device 1a of the first embodiment, but the main difference is that the ejector 41 is connected to the plurality of utilization side units 3a, 3b, 3c, 3d. The air conditioning device 1b of this embodiment includes a heat source side unit 2, an intermediate unit 4, four utilization side units 3a, 3b, 3c, 3d, and a control unit 50.

[0207] (2-2) Detailed structure

[0208] (2-2-1) Connecting pipes

[0209] The first communication pipe 5 , the second communication pipe 6 , and the third communication pipe 7 of the present embodiment are different from those of the first embodiment only in that they do not have a branch pipe portion.

[0210] (2-2-2) Heat source side unit

[0211] The heat source side unit 2 of this embodiment is different from that of the first embodiment in that the heat source side fifth pipe P25 is connected to the third communication pipe 7. Specifically, Figure 1 The fifth heat-source-side pipe P25 connected to the third communication pipe 7 in the illustrated first embodiment is connected between the third heat-source-side valve V23 and the refrigerant inlet 26 a of the gas-liquid separator 26 . Figure 8 The fifth heat source side pipe P25 of the illustrated embodiment is connected between the third communication pipe 7 and the third heat source side valve V23 .

[0212] (2-2-3) Using the side unit

[0213] The utilization side units 3a, 3b, 3c, and 3d of the present embodiment are the same as those of the first embodiment.

[0214] (2-2-4) Intermediate Unit

[0215] The intermediate unit 4 has an ejector 41 and a gas-liquid separator 42 .

[0216] One ejector 41 is switched so that the plurality of utilization side heat exchangers 31a, 31b, 31c, 31d individually function as evaporators or radiators of the refrigerant. The ejector 41 is connected to the plurality of utilization side units 3a, 3b, 3c, 3d. Therefore, one ejector 41 can increase the pressure of the refrigerant of each utilization side unit 3a, 3b, 3c, 3d. The refrigerant flowing out of the ejector 41 flows into the gas-liquid separator 42.

[0217] The ejector 41 of this embodiment has the same structure as the ejectors 41a, 41b, 41c, and 41d of Embodiment 1. Specifically, the ejector 41 includes a driving inlet 411, a suction inlet 412, and a discharge port 413.

[0218] The gas-liquid separator 42 of this embodiment has the same structure as the gas-liquid separators 42a, 42b, 42c, and 42d of Embodiment 1. Specifically, the gas-liquid separator 42 includes a refrigerant inlet 421, a liquid-side outlet 422, and a gas-side outlet 423.

[0219] The intermediate unit 4 also has an intermediate first pipeline P41, an intermediate second pipeline P42, an intermediate third pipeline P43, an intermediate fourth pipeline P44, an intermediate fifth pipeline P45, an intermediate sixth pipeline P46, an intermediate seventh pipeline P47, an intermediate first valve V41a, V41b, V41c, V41d, an intermediate second valve V42, an intermediate third valve V43a, an intermediate fourth valve V44a, an intermediate fifth valve V45a, and an intermediate sixth valve V46a.

[0220] The first intermediate pipe P41 allows the refrigerant to flow between the heat source side heat exchangers 23a, 23b and the first utilization side heat exchangers 31a, 31b, 31c, 31d. Here, the first intermediate pipe P41 connects the first communication pipe 5 and the fourth communication pipes 8a, 8b, 8c, 8d. Therefore, the first intermediate pipe P41 has first branch pipes P411, P412, P413, P414 that are branched from the first communication pipe 5 and connected to the fourth communication pipes 8a, 8b, 8c, 8d.

[0221] The first branch pipes P411, P412, P413, and P414 are provided with first intermediate valves V41a, V41b, V41c, and V41d. Here, the first intermediate valves V41a, V41b, V41c, and V41d are on-off valves.

[0222] The intermediate second pipe P42 branches from the intermediate first pipe P41 between the heat source side heat exchangers 23a, 23b and the intermediate first valves V41a, V41b, V41c, V41d, and supplies the refrigerant to flow to the drive inlet 411 of the ejector 41. Here, the intermediate second pipe P42 branches from the intermediate first pipe P41 and between the first communication pipe 5 and the intermediate first branch pipes P411, P412, P413, P414.

[0223] The intermediate second pipe P42 is provided with an intermediate second valve V42. Here, the intermediate second valve V42 is an on-off valve.

[0224] The third intermediate pipe P43 connects the fifth communication pipes 9a, 9b, 9c, 9d and the second communication pipe 6. Therefore, the third intermediate pipe P43 has four third branch pipes P431, P432, P433, P434 branched from the second communication pipe 6 and connected to the fifth communication pipes 9a, 9b, 9c, 9d.

[0225] The third branch pipes P431, P432, P433, and P434 are provided with third intermediate valves V43a, V43b, V43c, and V43d. Here, the third intermediate valves V43a, V43b, V43c, and V43d are on-off valves.

[0226] The fourth intermediate pipe P44 connects the fifth communication pipes 9a, 9b, 9c, 9d and the suction inlet 412 of the ejector 41. Therefore, the fourth intermediate pipe P44 has four fourth branch pipes P441, P442, P443, P444 connected to the fifth communication pipes 9a, 9b, 9c, 9d. The four fourth branch pipes P441, P442, P443, P444 converge in front of the suction inlet 412.

[0227] The fourth branch pipes P441, P442, P443, and P444 are provided with fourth intermediate valves V44a, V44b, V44c, and V44d. Here, the fourth intermediate valves V44a, V44b, V44c, and V44d are on-off valves.

[0228] The fifth intermediate pipe P45 connects the liquid side outlet 422 of the gas-liquid separator 42 and the fourth communication pipes 8a, 8b, 8c, 8d. Therefore, the fifth intermediate pipe P45 has four fifth branch pipes P451, P452, P453, P454 connected to the fourth communication pipes 8a, 8b, 8c, 8d.

[0229] The fifth branch pipes P451, P452, P453, and P454 are provided with fifth intermediate valves V45a, V45b, V45c, and V45d. The fifth intermediate valves V45a, V45b, V45c, and V45d are check valves that allow only the flow of refrigerant from the liquid side outlet 422a to the fourth communication pipes 8a, 8b, 8c, and 8d.

[0230] The sixth intermediate pipe P46 connects the gas-side outlet 423 of the gas-liquid separator 42 and the second communication pipe 6. The sixth intermediate pipe P46 is provided with a sixth intermediate valve V46. The sixth intermediate valve V46 is an electric valve.

[0231] The seventh intermediate pipe P47 connects the gas-side outlet 423 of the gas-liquid separator 42 and the third communication pipe 7 .

[0232] A stop valve is provided at the connection between the intermediate unit 4 and the communication pipe. The stop valve is a valve that is opened and closed manually. Here, three stop valves are provided at the connection between the intermediate unit 4 and the first communication pipe 5, the second communication pipe 6, and the third communication pipe 7. Specifically, the three stop valves are provided at the connection between the intermediate unit 4 and the first communication pipe 5, the connection between the intermediate unit 4 and the second communication pipe 6, and the connection between the intermediate unit 4 and the third communication pipe 7. In addition, here, eight stop valves are provided at the connection between the intermediate unit 4 and the fourth communication pipe 8a, 8b, 8c, 8d and the fifth communication pipe 9a, 9b, 9c, 9d. Specifically, eight stop valves are provided at the connection between the intermediate unit 4 and the fourth communication pipe 8a, 8b, 8c, 8d and the connection between the intermediate unit 4 and the fifth communication pipe 9a, 9b, 9c, 9d.

[0233] (2-2-5) Control Unit

[0234] Similar to the first embodiment, the control unit 50 controls the components of the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate unit 4. Specifically, the control unit 50 controls the compressor 21 and the switching mechanism 22a, 22b, 22c of the heat source side unit 2, the utilization side expansion valves 32a, 32b, 32c, 32d of the utilization side units 3a, 3b, 3c, 3d, the intermediate first valves V41a, V41b, V41c, V41d, the intermediate second valve V42, the intermediate third valves V43a, V43b, V43c, V43d, the intermediate fourth valves V44a, V44b, V44c, V44d, and the intermediate sixth valve V46 of the intermediate unit 4.

[0235] Specifically, the control unit 50 controls whether to operate the ejector 41 by controlling the intermediate first valves V41a, V41b, V41c, and V41d to be fully opened or fully closed. In addition, the control unit 50 controls the degree of pressure increase of the refrigerant after heat release in the utilization side units 3a, 3b, 3c, and 3d in the ejector 41 by the opening degree of the intermediate second valve V42.

[0236] The control unit 50 performs control so that the ejector 41 is not activated when the amount of power recovery is less than a predetermined amount, and so that the ejector 41 is activated when the amount of power recovery is greater than the predetermined amount.

[0237] (2-3) Operation

[0238] Similar to the first embodiment, the operation of the air conditioner 1b of this embodiment includes cooling operation only, cooling-dominated operation, cooling-heating equalization operation, heating-dominated operation, and heating-only operation. Figures 9 to 13, the five operating actions of the air conditioning device 1b are explained. Figures 9 to 13 In FIG. 1 , a thick pipe indicates a pipe through which the refrigerant flows, and a thin pipe indicates a pipe through which the refrigerant does not flow. A valve provided in a thick pipe is opened, and a valve provided in a thin pipe is closed.

[0239] Here, the ejector 41 of the intermediate unit 4 can be activated or deactivated in cooling only operation, cooling-dominated operation, cooling-heating equalization operation, and heating-dominated operation. On the other hand, the ejector is deactivated in heating only operation.

[0240] (2-3-1) Full refrigeration operation

[0241] (2-3-1-1) When the ejector is activated

[0242] like Fig. 9 As shown, in the cooling only operation, for example, all of the side units 3a, 3b, 3c, and 3d perform the cooling operation.

[0243] At this time, in the heat source side unit 2, under the action of the control unit 50, the switching mechanisms 22a and 22b are switched to connect the discharge side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b ( Fig. 9 The switching mechanism 22a and 22b are switched to the state shown by the solid line of the switching mechanism 22a and 22b, so that the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b function as a heat radiator of the refrigerant. In addition, under the action of the control unit 50, the switching mechanism 22c is switched to connect the suction side of the compressor 21 and the second connecting pipe 6 ( Figure 3 The state shown by the solid line of the switching mechanism 22c of the compressor 21 is set to send the refrigerant flowing in the second connecting pipe 6 to the suction side of the compressor 21. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a and the second heat source side expansion valve 24b are set to open (here, fully open), the heat source side first valve V21 is set to open, and the heat source side second valve V22 is set to fully closed.

[0244] In the intermediate unit 4, in order to make the injector 41 work, under the action of the control unit 50, the intermediate first valves V41a, V41b, V41c, and V41d are set to be closed, the intermediate second valve V42 is set to be open, the intermediate third valves V43a, V43b, V43c, and V43d are set to be closed, the intermediate third valves V44a, V44b, V44c, and V44d are set to be open, and the intermediate sixth valve V46 is set to be open.

[0245] In the usage-side units 3a, 3b, 3c, 3d, the opening degrees of the usage-side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the refrigeration load of each usage-side unit 3a, 3b, 3c, 3d.

[0246] In this way, when the components of the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate unit 4 are controlled by the control unit 50, the refrigerant in the supercritical state ejected from the compressor 21 is sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b via the switching mechanisms 22a and 22b. The refrigerant sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b is cooled by heat exchange with outdoor air in the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b, which function as heat radiators of the refrigerant, thereby releasing heat. The above refrigerant passes through the first heat source side expansion valve 24a and the second heat source side expansion valve 24b, then converges, and further flows out of the heat source side unit 2 via the heat source side first valve V21.

[0247] The refrigerant flowing out of the heat source side unit 2 is sent to the intermediate unit 4 through the first communication pipe 5. The refrigerant sent to the intermediate unit 4 flows into the driving inlet 411 of the ejector 41. The above refrigerant is mixed with the refrigerant evaporated in the evaporator (the refrigerant evaporated in the utilization side heat exchangers 31a, 31b, 31c, 31d that function as the evaporator of the refrigerant) from the suction inlet 412, and is ejected from the ejection port 413. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 41 flows into the refrigerant inlet 421 of the gas-liquid separator 42. Then, the refrigerant separated in the gas-liquid separator 42 and flowing out from the liquid side outlet 422 flows out of the intermediate unit 4 via the intermediate fifth valves V45a, V45b, V45c, V45d.

[0248] The refrigerant flowing out of the intermediate unit 4 is sent to the use side units 3a, 3b, 3c, 3d through the fourth communication pipes 8a, 8b, 8c, 8d. The refrigerant sent to the use side units 3a, 3b, 3c, 3d is sent to the use side heat exchangers 31a, 31b, 31c, 31d via the use side expansion valves 32a, 32b, 32c, 32d. The refrigerant sent to the use side heat exchangers 31a, 31b, 31c, 31d is heated by heat exchange with the indoor air supplied from the room in the use side heat exchangers 31a, 31b, 31c, 31d functioning as evaporators of the refrigerant, and evaporates. The above refrigerant flows out of the use side units 3a, 3b, 3c, 3d. On the other hand, the indoor air cooled in the use side heat exchangers 31a, 31b, 31c, 31d is sent to the room, thereby cooling the room.

[0249] The refrigerant flowing out of the utilization side units 3a, 3b, 3c, 3d is sent to the intermediate unit 4 through the fifth communication pipes 9a, 9b, 9c, 9d. The refrigerant sent to the intermediate unit 4 flows into the suction inlet 412 of the ejector 41 through the intermediate fourth valves V44a, V44b, V44c, V44d. The low-pressure refrigerant flowing into the ejector 41 is mixed with the refrigerant flowing in from the driving inlet 411 in the ejector 41, thereby increasing the pressure. The refrigerant in a two-phase state that is increased in pressure and ejected from the ejection port 413 flows into the refrigerant inlet 421 of the gas-liquid separator 42. Then, the refrigerant separated in the gas-liquid separator 42 and flowing out from the gas side outlet 423 is branched to the intermediate sixth pipe P46 and the intermediate seventh pipe P47, and flows out of the intermediate unit 4.

[0250] The refrigerant flowing out of the sixth intermediate pipe P46 of the intermediate unit 4 is sent to the heat source side unit 2 through the second communication pipe 6 . The refrigerant flowing out of the seventh intermediate pipe P47 of the intermediate unit 4 is sent to the heat source side unit 2 through the third communication pipe 7 .

[0251] The refrigerant sent from the second communication pipe 6 to the heat source side unit 2 flows into the refrigerant inlet 26a of the gas-liquid separator 26 via the switching mechanism 22c and the third heat source side valve V23. The refrigerant sent from the third communication pipe 7 to the heat source side unit 2 also flows into the refrigerant inlet 26a of the gas-liquid separator 26 via the third heat source side valve V23. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0252] In this way, when performing the above-mentioned full refrigeration operation, the ejector 41 of the intermediate unit 4 is activated to increase the pressure of the refrigerant after evaporation in the side units 3a, 3b, 3c, and 3d used for refrigeration operation, and then return it to the compressor 21 through the second connecting pipe 6 and the third connecting pipe 7.

[0253] (2-3-1-2) Situations that make the ejector inoperative

[0254] In the intermediate unit 4, when the injector 41 is rendered inoperative, under the action of the control unit 50, the intermediate first valves V41a, V41b, V41c, and V41d are set to open, the intermediate second valve V42 is set to closed, the intermediate third valves V43a, V43b, V43c, and V43d are set to open, the intermediate third valves V44a, V44b, V44c, and V44d are set to open, and the intermediate sixth valve V46 is set to open.

[0255] In this case, the refrigerant sent from the heat source side unit 2 to the intermediate unit 4 does not pass through the ejector 41, but flows out from the intermediate first pipe P41 through the fourth communication pipes 8a, 8b, 8c, 8d to the usage side units 3a, 3b, 3c, 3d.

[0256] The refrigerant sent from the utilization side units 3a, 3b, 3c, 3d through the fifth connecting pipes 9a, 9b, 9c, 9d to the intermediate units 4a, 4b, 4c, 4d does not pass through the ejector 41, but flows out from the intermediate third pipe P43 through the second connecting pipe 6 to the heat source side unit 2.

[0257] (2-3-2) Refrigeration main operation

[0258] (2-3-2-1) When the ejector is activated

[0259] like Fig.10 As shown, in the cooling main operation, for example, the side units 3b, 3c, and 3d are used to perform the cooling operation, and the side unit 3a is used to perform the heating operation.

[0260] At this time, in the heat source side unit 2, under the action of the control unit 50, the switching mechanism 22a is switched to connect the discharge side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a ( Fig.10 The switching mechanism 22a is switched to the state shown by the solid line of the switching mechanism 22a, so that the first heat source side heat exchanger 23a functions as a heat radiator of the refrigerant. In addition, under the action of the control unit 50, the switching mechanism 22c is switched to connect the discharge side of the compressor 21 with the second communication pipe 6 ( Fig.10 The switching mechanism 22c is in the state shown by the solid line of the switching mechanism 22c) to send the refrigerant ejected from the compressor 21 to the second communication pipe 6. In addition, here, since the refrigerant does not flow in the switching mechanism 22b, the switching mechanism 22b is not controlled by the control unit 50. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to be fully opened, the second heat source side expansion valve 24b is set to be fully closed, the heat source side first valve V21 is set to be opened, and the heat source side second valve V22 is set to be fully closed.

[0261] In the intermediate unit 4, under the action of the control unit 50, the intermediate first valve V41a is set to open, the intermediate first valves V41b, V41c, and V41d are set to closed, the intermediate second valve V42 is set to open, the intermediate third valve V43a is set to open, the intermediate third valves V43b, V43c, and V43d are set to closed, the intermediate fourth valve V44a is set to closed, the intermediate fourth valves V44b, V44c, and V44d are set to open, and the intermediate sixth valve V46a is set to closed.

[0262] In the utilization side units 3a, 3b, 3c, 3d, the opening degrees of the utilization side expansion valves 32a, 32b, 32c, 32d are adjusted according to the heating load of the utilization side unit 3a and the cooling load of the utilization side units 3b, 3c, 3d under the control of the control unit 50.

[0263] In this way, when the components of the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate unit 4 are controlled by the control unit 50, a part of the supercritical refrigerant ejected from the compressor 21 is sent to the first heat source side heat exchanger 23a through the first switching mechanism 22a, and the remaining part flows out from the heat source side unit 2 to the second communication pipe 6 through the third switching mechanism 22c. The refrigerant sent to the first heat source side heat exchanger 23a exchanges heat with the outdoor air in the first heat source side heat exchanger 23a, which functions as a heat radiator of the refrigerant, and is cooled to release heat. The above-mentioned refrigerant flows out from the heat source side unit 2 to the first communication pipe 5 via the first heat source side expansion valve 24a and the heat source side first valve V21. The refrigerant flowing out to the first communication pipe 5 is sent to the intermediate first pipe P41 of the intermediate unit 4.

[0264] The refrigerant flowing out of the second communication pipe 6 is sent to the third intermediate pipe P43 of the intermediate unit 4. The high-pressure refrigerant flows out of the intermediate unit 4 via the third intermediate valve V43a.

[0265] The refrigerant flowing out of the intermediate unit 4 is sent to the utilization side unit 3a through the fifth connecting pipe 9a. The refrigerant sent to the utilization side unit 3a is sent to the utilization side heat exchanger 31a. The high-pressure refrigerant sent to the utilization side heat exchanger 31a is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchanger 31a, which functions as a heat releaser of the refrigerant, thereby releasing heat. The above-mentioned refrigerant flows out of the utilization side unit 3a through the utilization side expansion valve 32a set to be fully opened. On the other hand, the indoor air heated in the utilization side heat exchanger 31a is sent to the room, thereby heating the room.

[0266] The refrigerant flowing out of the utilization side unit 3a is sent to the intermediate unit 4 through the fourth communication pipe 8a. The refrigerant sent to the intermediate unit 4 flows into the first branch pipe P411, and merges with the refrigerant flowing out of the first heat source side heat exchanger 23a to the first communication pipe 5 and flowing into the first branch pipe P411 at point A. The merged refrigerant flows into the drive inlet 411 of the ejector 41 through the intermediate second pipe P42. Then, the above refrigerant is mixed with the refrigerant evaporated in the evaporator (the refrigerant evaporated in the utilization side heat exchangers 31b, 31c, 31d that function as the evaporator of the refrigerant) from the suction inlet 412, and is ejected from the ejection port 413. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 41 flows into the refrigerant inlet 421 of the gas-liquid separator 42. Next, the refrigerant separated in the gas-liquid separator 42 and flowing out from the liquid-side outlet 422 branches to the fifth branch pipes P452 , P453 , and P454 , and flows out of the intermediate unit 4 via the fifth intermediate valves V45b , V45c , and V45d .

[0267] The refrigerant flowing out of the intermediate unit 4 is sent to the utilization side units 3b, 3c, 3d through the fourth communication pipes 8b, 8c, 8d. The refrigerant sent to the utilization side units 3b, 3c, 3d is sent to the utilization side heat exchangers 31b, 31c, 31d via the utilization side expansion valves 32b, 32c, 32d. The refrigerant sent to the utilization side heat exchangers 31b, 31c, 31d is heated by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31b, 31c, 31d, which function as evaporators of the refrigerant, and evaporates. The refrigerant flows out of the utilization side units 3b, 3c, 3d. On the other hand, the indoor air cooled in the utilization side heat exchangers 31b, 31c, 31d is sent to the room, thereby cooling the room.

[0268] The refrigerant flowing out of the utilization side units 3b, 3c, 3d is sent to the intermediate unit 4 through the fifth communication pipes 9b, 9c, 9d. The refrigerant sent to the intermediate unit 4 converges at the intermediate fourth pipe P44 through the intermediate fourth valves V44b, V44c, V44d, and flows into the suction inlet 412 of the ejector 41. The low-pressure refrigerant flowing into the ejector 41 is mixed with the refrigerant flowing in from the drive inlet 411 in the ejector 41, thereby increasing the pressure. The refrigerant in the two-phase state that is increased in pressure and ejected flows into the refrigerant inlet 421 of the gas-liquid separator 42. Then, the refrigerant separated in the gas-liquid separator 42 and flowing out from the gas side outlet 423 flows out of the intermediate unit 4 through the intermediate seventh pipe P47.

[0269] The refrigerant flowing out of the intermediate unit 4 is sent to the heat source side unit 2 through the third communication pipe 7 .

[0270] The refrigerant sent to the heat source side unit 2 flows into the refrigerant inlet 26a of the gas-liquid separator 26 via the heat source side third valve V23. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0271] Thus, when the cooling main operation is performed, the ejector 41 of the intermediate unit 4 is activated to increase the pressure of the refrigerant evaporated in the utilization side units 3d, 3c, and 3d performing the cooling operation, and then return the refrigerant to the compressor 21 through the third communication pipe 7. In addition, the refrigerant that releases heat in the utilization side unit 3a performing the heating operation is not pressurized in the ejector 41a.

[0272] (2-3-2-2) Situations where the ejector does not function

[0273] In the intermediate unit 4, when the injector 41 is rendered inoperative, under the action of the control unit 50, the intermediate first valves V41a, V41b, V41c, and V41d are set to be open, the intermediate second valve V42 is set to be closed, the intermediate third valves V43b, V43c, and V43d are set to be closed, the intermediate third valves V44b, V44c, and V44d are set to be open, and the intermediate sixth valve V46 is set to be closed.

[0274] In this case, the refrigerant sent from the heat source side unit 2 to the intermediate unit 4 through the first communication pipe 5 does not pass through the ejector 41, but flows out of the intermediate unit 4 from the intermediate first pipe P41 through the first branch pipes P412, P413, P414. The above refrigerant flows out to the use side units 3b, 3c, 3d through the fourth communication pipes 8b, 8c, 8d. The refrigerant that undergoes heat exchange in the use side heat exchanger 31a, 31b, 31c, 31d and is sent from the use side unit 3b, 3c, 3d to the intermediate unit 4b, 4c, 4d passes through the check valve via the intermediate fourth valve V44b, V44c, V44d, and flows out of the intermediate unit 4. The refrigerant flowing out of the intermediate units 4b, 4c, 4d flows into the heat source side unit 2 through the third communication pipe 7.

[0275] (2-3-3)Equal operation of hot and cold

[0276] (2-3-3-1) When the ejector is activated

[0277] like Fig.11 As shown, in the hot and cold equal operation, for example, the side units 3c and 3d are used for cooling operation and the side units 3a and 3b are used for heating operation (that is, the side heat exchangers 31c and 31d act as evaporators of the refrigerant and the side heat exchangers 31a and 31b act as radiators of the refrigerant).

[0278] At this time, in the heat source side unit 2, under the action of the control unit 50, the first switching mechanism 22a is switched to connect the discharge side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a ( Fig.11 In addition, under the action of the control unit 50, the second switching mechanism 22b is switched to connect the suction side of the compressor 21 and the gas side of the second heat source side heat exchanger 23b ( Fig.11 In addition, under the action of the control unit 50, the third switching mechanism 22c is switched to connect the discharge side of the compressor 21 and the second communication pipe 6 ( Fig.11The state shown by the solid line of the switching mechanism 22c of the compressor 21 is so that the refrigerant ejected from the compressor 21 is sent to the second connecting pipe 6. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to open, the second heat source side expansion valve 24b is set to slightly open, the heat source side first valve V21 is set to open, and the heat source side second valve V22 is set to fully closed.

[0279] In the intermediate unit 4, under the action of the control unit 50, the intermediate first valves V41a and 41b are set to open, the intermediate first valves V41c and V41d are set to closed, the intermediate second valve V42 is set to open, the intermediate third valves V43a and V43b are set to open, the intermediate third valves V43c and V43d are set to closed, the intermediate fourth valves V44a and V44b are set to closed, the intermediate fourth valves V44c and V44d are set to open, and the intermediate sixth valve V46 is set to closed.

[0280] In the utilization side units 3a, 3b, 3c, 3d, the opening degrees of the utilization side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the heating load of the utilization side units 3a, 3b and the cooling load of the utilization side units 3c, 3d.

[0281] In this way, the control unit 50 controls the components of the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d, and the intermediate units 4a, 4b, 4c, 4d. First, the case where the sum of the cooling operation loads of the utilization side units 3a, 3b, 3c, 3d is equal to the sum of the heating operation loads is described.

[0282] Part of the supercritical refrigerant discharged from the compressor 21 is sent to the first heat source side heat exchanger 23a through the first switching mechanism 22a, and the remaining part flows out of the heat source side unit 2 to the second communication pipe 6 through the third switching mechanism 22c.

[0283] The refrigerant sent to the first heat source side heat exchanger 23a exchanges heat with the outdoor air in the first heat source side heat exchanger 23a, which functions as a heat radiator of the refrigerant, and is cooled, thereby releasing heat. Then, the refrigerant is sent from the first heat source side heat exchanger 23a to the second heat source side heat exchanger 23b via the first heat source side expansion valve 24a and the second heat source side expansion valve 24b. The refrigerant sent to the second heat source side heat exchanger 23b passes through the gas-liquid separator 26 via the second switching mechanism 22b and the heat source side third valve V23, and returns to the compressor 21.

[0284] The refrigerant flowing out of the second communication pipe 6 is sent to the intermediate unit 4 through the second communication pipe 6. The high-pressure refrigerant sent to the intermediate unit 4 flows into the intermediate third pipe P43 and flows out of the intermediate units 4a and 4b through the intermediate third valves V43a and V43b.

[0285] The refrigerant flowing out of the intermediate units 4a and 4b is sent to the utilization side units 3a and 3b through the fifth connecting pipes 9a and 9b. The refrigerant sent to the utilization side units 3a and 3b is sent to the utilization side heat exchangers 31a and 31b. The high-pressure refrigerant sent to the utilization side heat exchangers 31a and 31b is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31a and 31b, which function as heat radiators of the refrigerant, thereby releasing heat. The above-mentioned refrigerant flows out of the utilization side units 3a and 3b through the utilization side expansion valves 32a and 32b. On the other hand, the indoor air heated in the utilization side heat exchangers 31a and 31b is sent to the room, thereby heating the room.

[0286] The refrigerant flowing out of the utilization side units 3a and 3b is sent to the intermediate unit 4 through the fourth communication pipes 8a and 8b. The refrigerant sent to the intermediate unit 4 flows into the first branch pipes P411 and P412, and flows into the drive inlet 411 of the ejector 41 through the intermediate first valves V41a and V41b and the second valve V42. The above refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 412, and is ejected from the ejection port 413. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 41 flows into the refrigerant inlet 421 of the gas-liquid separator 42. Then, the refrigerant separated in the gas-liquid separator 42 and flowing out from the liquid side outlet 422 flows out of the intermediate units 4b, 4c, and 4d through the intermediate fifth valves V45c and V45d.

[0287] The refrigerant flowing out of the intermediate units 4c and 4d is sent to the utilization side units 3c and 3d through the fourth connecting pipes 8c and 8d. The refrigerant sent to the utilization side units 3c and 3d is sent to the utilization side heat exchangers 31c and 31d via the utilization side expansion valves 32c and 32d. The refrigerant sent to the utilization side heat exchangers 31c and 31d is heated by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31c and 31d, which function as evaporators of the refrigerant, and evaporates. The above-mentioned refrigerant flows out of the utilization side units 3c and 3d. On the other hand, the indoor air cooled in the utilization side heat exchangers 31c and 31d is sent to the room, thereby cooling the room.

[0288] The refrigerant flowing out of the utilization side units 3c and 3d is sent to the intermediate unit 4 through the fifth communication pipes 9c and 9d. The refrigerant sent to the intermediate unit 4 flows into the suction inlet 412 of the ejector 41 through the intermediate fourth valves V44c and V44d. The low-pressure refrigerant flowing into the ejector 41 is mixed with the refrigerant flowing in from the driving inlet 411 in the ejector 41, thereby increasing the pressure. The refrigerant in the two-phase state that is pressurized and ejected flows into the refrigerant inlet 421 of the gas-liquid separator 42. Then, the refrigerant separated in the gas-liquid separator 42 and flowing out from the gas side outlet 423 flows out of the intermediate unit 4 through the intermediate seventh pipe P47.

[0289] The refrigerant flowing out of the intermediate unit 4 is sent to the heat source side unit 2 through the third communication pipe 7. The refrigerant sent to the heat source side unit 2 passes through the heat source side fifth pipe P25 and flows into the refrigerant inlet 26a of the gas-liquid separator 26 via the heat source side third valve V23. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0290] Next, a case where the sum of the cooling operation loads of the usage-side units 3 c and 3 d increases compared to the sum of the heating operation loads of the usage-side units 3 a and 3 b will be described.

[0291] In the heat source side unit 2, the refrigerant after releasing heat in the first heat source side heat exchanger 23a functioning as a heat releaser of the refrigerant flows out of the heat source side unit 2 to the first communication pipe 5 via the first heat source side expansion valve 24a and the heat source side first valve V21. The refrigerant passes through the first communication pipe 5 and flows into the intermediate first pipe P41 of the intermediate unit 4. The refrigerant merges with the refrigerant that has exchanged heat in the utilization side heat exchangers 31a and 31b and passed through the intermediate first valves V41a and V41b at point A. The merged refrigerant flows into the drive inlet 411 of the ejector 41 via the intermediate second valve V42.

[0292] Next, a case where the sum of the heating operation loads of the usage-side units 3 a and 3 b increases compared to the sum of the cooling operation loads of the usage-side units 3 c and 3 d will be described.

[0293] The refrigerant that has undergone heat exchange in the utilization side heat exchangers 31a and 31b and further flows through the intermediate first pipe P41 of the intermediate units 4a and 4b and flows out of the intermediate unit 4 flows into the heat source side unit 2 through the first communication pipe 5. The above-mentioned refrigerant flows in the heat source side first pipe P21, and is sent to the second heat source side heat exchanger 23b through the heat source side first valve V21 and the second heat source side expansion valve 24b. The refrigerant evaporated in the second heat source side heat exchanger 23b flows into the refrigerant inlet 26a of the gas-liquid separator 26 through the second switching mechanism 22b and the heat source side third valve V23. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0294] Thus, when performing the above-mentioned cooling and heating equalization operation, the ejector 41 of the intermediate unit 4 is activated to increase the pressure of the refrigerant evaporated in the utilization side units 3c and 3d performing the cooling operation, and then return it to the compressor 21 through the third communication pipe 7. In addition, the refrigerant that releases heat in the utilization side units 3a and 3b performing the heating operation is not pressurized in the ejector 41a.

[0295] (2-3-3-2) Situations that make the ejector inoperative

[0296] In the intermediate unit 4, when the ejector 41 is disabled, the first intermediate valves V41c and V41d are opened, the second intermediate valves V42c and V42d are closed, the third intermediate valves V43c and V43d are closed, the fourth intermediate valves V44c and V44d are opened, and the sixth intermediate valve V46 is closed under the control of the control unit 50. The operation in this case is the same as that of the intermediate unit 4 in the cooling main operation.

[0297] (2-3-4) Heating main operation

[0298] (2-3-4-1) When the ejector is activated

[0299] like Fig.12 As shown, in the heating main operation, for example, the side unit 3d is used to perform the cooling operation, and the side units 3a, 3b, and 3c are used to perform the heating operation.

[0300] At this time, in the heat source side unit 2, under the action of the control unit 50, the first switching mechanism 22a and the second switching mechanism 22b are switched to connect the suction side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b ( Fig.12The first switching mechanism 22a and the second switching mechanism 22b are switched to the state shown by the solid line of the first switching mechanism 22a and 22b, so that the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b function as evaporators of the refrigerant. In addition, under the action of the control unit 50, the switching mechanism 22c is switched to connect the discharge side of the compressor 21 and the second connecting pipe 6 ( Fig.12 The state shown by the solid line of the switching mechanism 22c is to deliver the refrigerant ejected from the compressor 21 to the second connecting pipe 6. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to open, the second heat source side expansion valve 24b is set to open, the heat source side first valve V21 is set to close, and the heat source side second valve V22 is set to open.

[0301] In the intermediate unit 4, under the action of the control unit 50, the intermediate first valves V41a, 41b, and V41c are set to open, the intermediate first valve V41d is set to closed, the intermediate second valve V42 is set to open, the intermediate third valves V43a, V43b, and V43c are set to open, the intermediate third valve V43d is set to closed, the intermediate fourth valves V44a, V44b, and V44c are set to closed, the intermediate fourth valve V44d is set to open, and the intermediate sixth valve V46 is set to closed.

[0302] In the utilization side units 3a, 3b, 3c, 3d, the opening degrees of the utilization side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the heating load of the utilization side units 3a, 3b, 3c and the cooling load of the utilization side unit 3d.

[0303] In this way, when the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d and the intermediate units 4a, 4b, 4c, 4d are controlled by the control unit 50, the supercritical refrigerant ejected from the compressor 21 flows out from the heat source side unit 2 to the second connecting pipe 6 through the third switching mechanism 22c.

[0304] The refrigerant flowing out of the second communication pipe 6 is sent to the intermediate unit 4. The high-pressure refrigerant sent to the intermediate unit 4 flows into the intermediate third pipe P43 and flows out of the intermediate unit 4 via the intermediate third valves V43a, V43b, and V43c.

[0305] The refrigerant flowing out of the intermediate unit 4 is sent to the utilization side units 3a, 3b, 3c through the fifth communication pipes 9a, 9b, 9c. Then, the high-pressure refrigerant sent to the utilization side heat exchangers 31a, 31b, 31c is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31a, 31b, 31c, which function as heat radiators of the refrigerant, thereby releasing heat. The refrigerant flows out of the utilization side units 3a, 3b, 3c through the utilization side expansion valves 32a, 32b, 32c. On the other hand, the indoor air heated in the utilization side heat exchangers 31a, 31b, 31c is sent to the room, thereby heating the room.

[0306] The refrigerant flowing out of the utilization side units 3a, 3b, 3c is sent to the intermediate unit 4 through the fourth communication pipes 8a, 8b, 8c. The refrigerant sent to the intermediate unit 4 flows into the first branch pipes P411, P412, P413. The above refrigerant passes through the intermediate first valves V41a, V41b, V41c, and at point A, a part of it flows into the intermediate second pipe P42, and the rest flows from the intermediate unit 4 through the first communication pipe 5 to the heat source side unit 2, and flows into the drive inlet 25a of the ejector 25 through the heat source side second valve V22.

[0307] The refrigerant flowing into the second intermediate pipe P42 flows into the drive inlet 411 of the ejector 41. The refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 412 and is ejected from the ejection port 413. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 41 flows into the refrigerant inlet 421 of the gas-liquid separator 42. Then, the refrigerant separated in the gas-liquid separator 42 and flowing out from the liquid side outlet 422 flows out of the intermediate unit 4 via the fifth intermediate valve V45d.

[0308] The refrigerant flowing out of the intermediate unit 4 is sent to the use-side unit 3d through the fourth communication pipe 8d. The refrigerant sent to the use-side unit 3d is sent to the use-side heat exchanger 31d, which functions as an evaporator of the refrigerant, via the use-side expansion valve 32d, and is heated by heat exchange with the indoor air supplied from the room, thereby evaporating. The refrigerant flows out of the use-side unit 3d. On the other hand, the indoor air cooled in the use-side heat exchanger 31d is sent to the room, thereby cooling the room.

[0309] The refrigerant flowing out of the utilization side unit 3d is sent to the intermediate unit 4 through the fifth communication pipe 9d. The refrigerant sent to the intermediate unit 4 flows into the suction inlet 412 of the ejector 41 through the intermediate fourth pipe P44. The refrigerant flowing into the ejector 41 is mixed with the refrigerant flowing in from the driving inlet 411, thereby increasing the pressure. The refrigerant in a two-phase state that is increased in pressure and ejected from the ejection port 413 flows into the refrigerant inlet 421 of the gas-liquid separator 42. Then, the refrigerant separated in the gas-liquid separator 42 and flowing out from the gas side outlet 423 flows out of the intermediate unit 4 through the intermediate seventh pipe P47.

[0310] The refrigerant flowing out of the intermediate unit 4 is sent to the heat source side unit 2 through the third communication pipe 7. The refrigerant flows into the refrigerant inlet 26a of the gas-liquid separator 26 through the heat source side fifth pipe P25 and the third pipe P23.

[0311] In addition, the refrigerant that performs heat exchange in the utilization side heat exchangers 31a, 31b, and 31c and passes through the first communication pipe 5 from the point A of the intermediate unit 4 flows into the drive inlet 25a of the ejector 25 of the heat source side unit 2 via the heat source side second valve V22. The above refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 25b and is ejected from the ejection port 25c. The refrigerant in the gas-liquid two-phase state that flows out of the ejector 25 flows into the refrigerant inlet 26a of the gas-liquid separator 26.

[0312] The refrigerant separated in the gas-liquid separator 26 and flowing out of the liquid side outlet 26b is branched to flow to the first heat source side expansion valve 24a and the second heat source side expansion valve 24b via the heat source side fourth valve V24, and is sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b.

[0313] The refrigerant sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b is heated by heat exchange with outdoor air in the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b, which function as evaporators of the refrigerant, and evaporates. Each evaporated refrigerant flows into the suction inlet 25b of the ejector 25 via the first switching mechanism 22a and the second switching mechanism 22b. The low-pressure refrigerant is mixed with the refrigerant flowing in from the drive inlet 25a in the ejector 41d, thereby increasing the pressure. The refrigerant in the two-phase state that is pressurized and ejected flows into the refrigerant inlet 26a of the gas-liquid separator 26.

[0314] Next, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas-side outlet 26 c is sucked into the compressor 21 .

[0315] Thus, when the above-mentioned heating main operation is performed, the ejector 41 of the intermediate unit 4 is activated to increase the pressure of the refrigerant evaporated in the utilization side unit 3d performing the cooling operation, and then return it to the compressor 21 through the third communication pipe 7. In addition, the refrigerant that releases heat in the utilization side units 3a, 3b, and 3c performing the heating operation is not pressurized in the ejector 41a.

[0316] (2-3-4-2) Situations that make the ejector inoperative

[0317] In the intermediate unit 4, when the ejector 41d is disabled, the intermediate first valve V41d is opened, the intermediate second valve V42d is closed, the intermediate third valve V43d is closed, the intermediate fourth valve V44d is opened, and the intermediate sixth valve V46d is closed under the control of the control unit 50. The operation in this case is the same as that of the intermediate unit 4d in the cooling main operation.

[0318] (2-3-5) Full heating operation

[0319] like Fig.13 As shown, in full heating operation, for example, all the side units 3a, 3b, 3c, and 3d are used for heating operation (that is, all the side heat exchangers 31a, 31b, 31c, and 31d act as heat radiators of the refrigerant and the heat source side heat exchangers 23a and 23b act as evaporators of the refrigerant).

[0320] At this time, in the heat source side unit 2, under the action of the control unit 50, the first switching mechanism 22a and the second switching mechanism 22b are switched to connect the suction side of the compressor 21 and the gas side of the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b ( Fig.13 The first switching mechanism 22a and the second switching mechanism 22b are switched to the state shown by the solid line of the first switching mechanism 22a and 22b, so that the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b function as evaporators of the refrigerant. In addition, under the action of the control unit 50, the switching mechanism 22c is switched to connect the discharge side of the compressor 21 and the second connecting pipe 6 ( Fig.13 The state shown by the solid line of the switching mechanism 22c is to deliver the refrigerant ejected from the compressor 21 to the second connecting pipe 6. In addition, under the action of the control unit 50, the first heat source side expansion valve 24a is set to open, the second heat source side expansion valve 24b is set to open, the heat source side first valve V21 is set to close, and the heat source side second valve V22 is set to open.

[0321] In the intermediate unit 4, under the action of the control unit 50, the intermediate first valves V41a, V41b, V41c, and V41d are set to open, the intermediate second valve V42 is set to closed, the intermediate third valves V43a, V43b, V43c, and V43d are set to open, the intermediate fourth valves V44a, V44b, V44c, and V44d are set to closed, and the intermediate sixth valve V46 is set to closed.

[0322] In the usage-side units 3a, 3b, 3c, 3d, the opening degrees of the usage-side expansion valves 32a, 32b, 32c, 32d are adjusted by the control unit 50 according to the heating load of the usage-side units 3a, 3b, 3c, 3d.

[0323] In this way, when the heat source side unit 2, the utilization side units 3a, 3b, 3c, 3d and the intermediate unit 4 are controlled by the control unit 50, the supercritical refrigerant ejected from the compressor 21 flows out from the heat source side unit 2 to the second connecting pipe 6 through the third switching mechanism 22c.

[0324] The refrigerant flowing out of the second communication pipe 6 is sent to the intermediate unit 4. The high-pressure refrigerant sent to the intermediate unit 4 flows into the intermediate third pipe P43, further flows through the third branch pipes P431, P432, P433, and P434, and flows out of the intermediate unit 4 through the intermediate third valves V43a, V43b, V43c, and V43d.

[0325] The refrigerant flowing out of the intermediate unit 4 is sent to the utilization side units 3a, 3b, 3c, 3d through the fifth communication pipes 9a, 9b, 9c, 9d. Then, the high-pressure refrigerant sent to the utilization side heat exchangers 31a, 31b, 31c, 31d is cooled by heat exchange with the indoor air supplied from the room in the utilization side heat exchangers 31a, 31b, 31c, 31d, which function as heat radiators of the refrigerant, thereby releasing heat. The refrigerant flows out of the utilization side units 3a, 3b, 3c, 3d through the utilization side expansion valves 32a, 32b, 32c, 32d. On the other hand, the indoor air heated in the utilization side heat exchangers 31a, 31b, 31c, 31d is sent to the room, thereby heating the room.

[0326] The refrigerant flowing out of the utilization side units 3a, 3b, 3c, 3d is sent to the intermediate unit 4 through the fourth communication pipes 8a, 8b, 8c, 8d. The refrigerant sent to the intermediate unit 4 flows into the first branch pipes P411, P412, P413, P414, and converges through the intermediate first valves V41a, V41b, V41c, V41d. The converged refrigerant flows out of the intermediate unit 4 without passing through the ejector 41.

[0327] The refrigerant flowing out of the intermediate unit 4 flows into the heat source side unit 2 through the first communication pipe 5. The refrigerant flowing into the heat source side unit 2 flows into the drive inlet 25a of the ejector 25. The refrigerant is mixed with the refrigerant evaporated in the evaporator from the suction inlet 25b and ejected from the ejection port 25c. The refrigerant in the gas-liquid two-phase state flowing out of the ejector 25 flows into the refrigerant inlet 26a of the gas-liquid separator 26. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the liquid side outlet 26b is branched through the heat source side fourth valve V24 to flow to the first heat source side expansion valve 24a and the second heat source side expansion valve 24b, and is sent to the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b. The refrigerant is heated by heat exchange with outdoor air in the first heat source side heat exchanger 23a and the second heat source side heat exchanger 23b, which function as evaporators of the refrigerant, and evaporates. The evaporated refrigerant converges through the first switching mechanism 22a and the second switching mechanism 22b and flows into the suction inlet 25b of the ejector 25. The low-pressure refrigerant is mixed with the refrigerant flowing in from the driving inlet 25a in the ejector 25, thereby increasing the pressure. The two-phase refrigerant in the increased pressure and ejected flows into the refrigerant inlet 26a of the gas-liquid separator 26. Then, the refrigerant separated in the gas-liquid separator 26 and flowing out from the gas side outlet 26c is sucked into the compressor 21.

[0328] Thus, during the heating only operation, the ejector 41d of the intermediate unit 4 is inoperative. In other words, the refrigerant having released heat in the utilization side units 3a, 3b, 3c, 3d performing the heating operation is configured not to be pressurized in the ejectors 41a, 41b, 41c, 41d.

[0329] (2-4) Features

[0330] The ejector 41 of this embodiment is connected to the plurality of usage-side units 3a, 3b, 3c, and 3d. Thus, the air-conditioning apparatus 1b of this embodiment can also be applied to a refrigerant circuit in which one ejector 41 can increase the pressure of the refrigerant in the plurality of usage-side units 3a, 3b, 3c, and 3d.

[0331] (3) Modification

[0332] (3-1) Modification A

[0333] In the first and second embodiments, the refrigerant after heat release in the utilization side units 3a, 3b, 3c, 3d in the heating operation does not pass through the ejectors 41, 41a, 41b, 41c, 41d, but the present invention is not limited thereto. In this modification, the refrigerant after heat release in the utilization side units 3a, 3b, 3c, 3d in the heating operation passes through the ejectors 41, 41a, 41b, 41c, 41d, but the pressure is not increased in the ejectors 41, 41a, 41b, 41c, 41d. In this case, for example, the driving flow does not flow to the ejectors 41, 41a, 41b, 41c, 41d.

[0334] In addition, although the driving flow flows to the ejectors 41, 41a, 41b, 41c, 41d, the suction flow (the refrigerant after releasing heat in the side units 3a, 3b, 3c, 3d for heating operation) does not flow to the suction flow inlet 412, 412a, 412b, 412c, 412d.

[0335] (3-2) Modification B

[0336] In the first and second embodiments described above, the heat source side unit 2 includes the ejector 25 , but the present invention is not limited thereto. In the present modification, the heat source side unit 2 does not include the ejector 25 .

[0337] (3-3) Modification C

[0338] In the first embodiment, each ejector 41a, 41b, 41c, 41d increases the pressure of the refrigerant of all the utilization side units 3a, 3b, 3c, 3d included in the air conditioning device 1a. In the second embodiment, one ejector 41 increases the pressure of the refrigerant of all the utilization side units 3a, 3b, 3c, 3d included in the air conditioning device 1b. In this modified example, the air conditioning device includes a plurality of ejectors. The first ejector increases the pressure of the refrigerant of one utilization side unit included in the air conditioning device. The second ejector increases the pressure of the refrigerant of a plurality of utilization side units included in the air conditioning device.

[0339] (3-4) Modification D

[0340] In the air-conditioning device 1a of the first embodiment and the air-conditioning device 1b of the second embodiment, the case where carbon dioxide is used as the refrigerant is described. As the refrigerant used in the air-conditioning device, carbon dioxide or a mixed refrigerant containing carbon dioxide with a high refrigerant pressure ejected from the compressor 21 is preferred, but it is not limited thereto, and refrigerants other than carbon dioxide or a mixed refrigerant containing carbon dioxide may also be used. For example, a refrigerant whose saturation pressure is 4.5 MPa or more when the saturation temperature reaches 65°C may also be used. As such a refrigerant, for example, R410A may be used. In addition, a Freon-type refrigerant that is in a critical state when discharged from the compressor 21 may also be used. As such a Freon-type refrigerant, for example, R23 may be used.

[0341] (3-5) Modification E

[0342] In the air conditioner 1a of the first embodiment and the air conditioner 1b of the second embodiment, there are three communication pipes 5, 6, 7 connecting the heat source side unit 2 and the intermediate units 4, 4a, 4b, 4c, 4d, but there may be four or more communication pipes.

[0343] As mentioned above, although the embodiment of this disclosure is described, it should be understood that various changes in form and details can be made without departing from the spirit and scope of this disclosure described in the claims.

[0344] Explanation of symbols

[0345] 1a, 1b: Air conditioning unit

[0346] 2: Heat source side unit

[0347] 3a, 3b, 3c, 3d: Using side units

[0348] 4, 4a, 4b, 4c, 4d: Intermediate units

[0349] 5, 6, 7: Connecting pipes

[0350] 21: Compressor

[0351] 23a, 23b: Heat exchanger on the heat source side

[0352] 31a, 31b, 31c, 31d: Utilization side heat exchanger

[0353] 41, 41a, 41b, 41c, 41d: Ejector

[0354] 42, 42a, 42b, 42c, 42d: Gas-liquid separator

[0355] 50: Control Department

[0356] 411, 411a, 411b, 411c, 411d: driving flow inlet

[0357] P41, P41a, P41b, P41c, P41d: First piping

[0358] P42, P42a, P42b, P42c, P42d: Second piping

[0359] V41a, V41b, V41c, V41d: First valve

[0360] V42, V42a, V42b, V42c, V42d: Second valve

[0361] Prior art literature

[0362] Patent Literature

[0363] Patent Document 1: Japanese Patent Application Publication No. 2005-337659.

Claims

1. An air conditioning device, characterized in that: include: A heat source side unit (2), the heat source side unit comprising a compressor (21) and a heat source side heat exchanger (23a); A plurality of utilization side units (3a, 3b), wherein the plurality of utilization side units have a utilization side heat exchanger; an intermediate unit (4a) that switches the plurality of utilization-side heat exchangers so that they individually function as evaporators or radiators of the refrigerant; and three or more connecting pipes (5, 6, 7), wherein the three or more connecting pipes connect the heat source side unit and the intermediate unit, The intermediate unit has: an ejector (41a, 41b) which increases the pressure of the refrigerant; and a gas-liquid separator (42a), into which the refrigerant flowing out of the ejector flows, The refrigerant having released heat in the utilization-side unit in the heating operation is configured not to be pressurized in the ejector. The intermediate unit has a plurality of the ejectors corresponding to a plurality of the utilization-side units. The refrigerant evaporated in the utilization side unit in cooling operation is configured to flow in the ejector. The intermediate unit also has: a first pipe (P41a) for allowing the refrigerant to flow between the heat source side heat exchanger and the utilization side heat exchanger; a first valve (V41a), the first valve being provided in the first pipe; a second pipe (P42a) branched from the first pipe between the heat source side heat exchanger and the first valve and used for allowing the refrigerant to flow to the drive inlet (411a) of the ejector; a second valve (V42a), the second valve being provided in the second pipe; as well as a third pipe (P45a), the third pipe being used for allowing the refrigerant to flow from the liquid side outlet (422a) of the gas-liquid separator to the utilization side heat exchanger, The air conditioning device further comprises a control unit (50) which controls the first valve and the second valve.

2. The air conditioning device according to claim 1, characterized in that: Each of the ejectors is connected to each of the utilization-side units.

3. The air conditioning device according to claim 1 or 2, characterized in that: The compressor ejects the refrigerant in a supercritical state.

4. The air conditioning device according to claim 3, characterized in that: The refrigerant compressed in the compressor contains carbon dioxide.

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