Air conditioner

Abstract

Provided is an air conditioner including a heat source machine, a plurality of relay devices, a plurality of load devices, and a plurality of connection pipes. The heat source machine includes a first refrigerant circuit, and the first refrigerant circuit has a first intermediate heat exchanger and an air heat exchanger. The plurality of relay devices include second refrigerant circuits, and the second refrigerant circuits each have a second intermediate heat exchanger and a third intermediate heat exchanger. The air conditioner is configured such that a heat transfer medium flows between the heat source machine, the plurality of relay devices, and at least one of the plurality of load devices, via the plurality of connection pipes. The flow rate of the heat transfer medium flowing through each of the plurality of relay devices is adjusted between the plurality of relay devices.

Description

air conditioning equipment

[0001] The present disclosure relates to an air conditioning apparatus.

[0002] Various air conditioners that utilize heat exchange between a refrigerant and a heat transfer medium such as water have been disclosed. For example, Patent Document 1 discloses a water chiller / heater multi-air conditioner that includes two outdoor water chillers and multiple indoor units installed on each floor of a building. In this water chiller / heater multi-air conditioner, each outdoor unit is connected to the multiple indoor units by a water chiller / heater pipe, and one outdoor unit is used for cooling operation and the other outdoor unit is used for heating operation, allowing each indoor unit to perform cooling and heating operation simultaneously.

[0003] Japanese Patent Application Publication No. 4-214134

[0004] However, the hot and cold water multi-air conditioner of Patent Document 1 requires two hot and cold water pipes connected to one outdoor unit for circulating cold water, and two hot and cold water pipes connected to the other outdoor unit for circulating hot water. Therefore, two hot and cold water pipes must be installed for each outdoor unit installed outdoors, and the large number of hot and cold water pipes required results in a heavy workload for piping work.

[0005] The present disclosure is intended to solve the above-mentioned problems, and aims to provide an air conditioning apparatus that can simultaneously perform cooling and heating using multiple load devices, and that can reduce the number of pipes connected to the heat source unit that serves as the outdoor unit.

[0006] An air conditioning apparatus according to the present disclosure includes at least one heat source unit, a plurality of relay units connected to the at least one heat source unit, a plurality of load devices connected to the plurality of relay units, and a plurality of connection pipes connecting the at least one heat source unit, the plurality of relay units, and the plurality of load devices, wherein the at least one heat source unit includes a first refrigerant circuit through which a refrigerant circulates, the first refrigerant circuit having a first intermediate heat exchanger that exchanges heat between the refrigerant flowing in the first refrigerant circuit and a heat transfer medium flowing therein, and an air heat exchanger that exchanges heat between the refrigerant flowing in the first refrigerant circuit and air, and The relay unit has a second refrigerant circuit through which refrigerant circulates, and the second refrigerant circuit has a second intermediate heat exchanger in which heat is exchanged between the refrigerant flowing through the second refrigerant circuit and the heat transfer medium flowing inside, and a third intermediate heat exchanger in which heat is exchanged between the refrigerant flowing through the second refrigerant circuit and the heat transfer medium flowing inside, and is configured so that the heat transfer medium flows between at least one heat source unit, multiple relay units, and at least one of the multiple load devices via multiple connecting pipes, and the flow rate of the heat transfer medium flowing through each of the multiple relay units is adjusted between the multiple relay units.

[0007] According to the present disclosure, when cooling and heating are performed simultaneously on multiple load devices, cooling or heating can be performed using the first refrigerant circuit provided in the heat source unit and the second refrigerant circuit provided in the relay unit, respectively, thereby reducing the number of pipes connected to the heat source unit.

[0008] 1 is a schematic configuration diagram of an air conditioning apparatus according to Embodiment 1. FIG. 2 is a circuit diagram showing an example of an air conditioning apparatus according to Embodiment 1. FIG. 3 is a circuit diagram showing an example of a cooling operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 4 is a circuit diagram showing an example of a heating operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 5 is a circuit diagram showing an example of a cooling-dominated operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 6 is a circuit diagram showing an example of a heating-dominated operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 7 is a schematic configuration diagram of an air conditioning apparatus according to Embodiment 2. FIG. 8 is a circuit diagram showing an example of a cooling-dominated operation mode in an air conditioning apparatus according to Embodiment 2. FIG. 9 is a circuit diagram showing another example of a cooling-dominated operation mode in an air conditioning apparatus according to Embodiment 2. FIG. 10 is a schematic configuration diagram of an air conditioning apparatus according to Embodiment 3. FIG. 11 is a circuit diagram showing an example of a cooling-dominated operation mode in an air conditioning apparatus according to Embodiment 3. FIG. 12 is a circuit diagram showing another example of a cooling-dominated operation mode in an air conditioning apparatus according to Embodiment 3. FIG. 13 is a flow diagram showing an example of control by a control device in an air conditioning apparatus according to Embodiment 3. FIG. 14 is a schematic configuration diagram of an air conditioning apparatus according to Embodiment 4. FIG. 15 is a schematic circuit diagram of an air conditioning apparatus according to Embodiment 4. 1 is a circuit diagram schematically showing a first variant of an air conditioning apparatus according to embodiment 4. FIG. 2 is a circuit diagram showing an example of a cooling operation mode in an air conditioning apparatus according to embodiment 4. FIG. 3 is a circuit diagram showing an example of a heating operation mode in an air conditioning apparatus according to embodiment 4. FIG. 4 is a circuit diagram showing an example of a cooling-dominated operation mode in a second variant of an air conditioning apparatus according to embodiment 4. FIG. 5 is a circuit diagram showing an example of a heating-dominated operation mode in a second variant of an air conditioning apparatus according to embodiment 4. FIG. 6 is a circuit diagram schematically showing an air conditioning apparatus according to embodiment 5. FIG. 7 is a circuit diagram schematically showing an air conditioning apparatus according to embodiment 6. FIG. 8 is a circuit diagram showing an example of a cooling operation mode in an air conditioning apparatus according to embodiment 6. FIG. 9 is a circuit diagram showing an example of a heating operation mode in an air conditioning apparatus according to embodiment 6. FIG. 10 is a circuit diagram showing an example of a cooling-dominated operation mode in an air conditioning apparatus according to embodiment 6. FIG. 11 is a circuit diagram showing an example of a heating-dominated operation mode in an air conditioning apparatus according to embodiment 6. FIG. 12 is a configuration diagram schematically showing an air conditioning apparatus according to embodiment 7.FIG. 13 is a schematic diagram illustrating a modified example of an air conditioning apparatus according to the seventh embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and their description will be omitted or simplified as appropriate. Furthermore, the shape, size, arrangement, etc. of the configurations shown in each drawing may be changed as appropriate.

[0010] Embodiment 1. [Air Conditioning Apparatus 100] Fig. 1 is a schematic diagram showing an air conditioning apparatus 100 according to Embodiment 1. Fig. 2 is a circuit diagram showing an example of an air conditioning apparatus 100 according to Embodiment 1. Note that the dashed arrows shown in Fig. 2 indicate an example of the flow of the heat transfer medium. The flow of the heat transfer medium is not limited to the flow shown in Fig. 2. Furthermore, the temperatures used in the following explanation are merely examples and are not limited to the temperatures described. The air conditioning apparatus 100 will be described using Figs. 1 and 2.

[0011] The air conditioning apparatus 100 is an apparatus that performs air conditioning by heating or cooling a room by transferring heat between outside air and indoor air via a refrigerant and a heat transfer medium. As shown in FIGS. 1 and 2 , the air conditioning apparatus 100 according to Embodiment 1 includes a heat source unit 1, a relay unit 2 connected to the heat source unit 1, and a load device 3 connected to the relay unit 2. The air conditioning apparatus 100 also includes a plurality of connection pipes 70 that connect the heat source unit 1, the relay unit 2, and the load device 3. The air conditioning apparatus 100 also includes a control device 40. The components that make up the heat source unit 1, the relay unit 2, and the load device 3 are controlled by the control device 40.

[0012] The air conditioning apparatus 100 is configured so that a heat transfer medium flows between at least one heat source unit 1, multiple relay units 2, and at least one of multiple load devices 3 via multiple connection pipes 70. The air conditioning apparatus 100 is a system composed of a heat source unit 1, multiple relay units 2, and a group of load devices 3, and the heat source unit 1 and the relay units 2 generate chilled or hot water in a refrigeration cycle, and transport heat between each unit using the chilled or hot water. The air conditioning apparatus 100 is a device in which the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 is adjusted between the multiple relay units 2.

[0013] [Heat source unit 1] The air conditioning apparatus 100 includes at least one heat source unit 1. One example of the heat source unit 1 is an outdoor unit. The heat source unit 1 is installed, for example, on the roof of a building 200. Note that although the air conditioning apparatus 100 includes one heat source unit 1 in FIGS. 1 and 2 , the air conditioning apparatus 100 may include multiple heat source units 1.

[0014] At least one heat source unit 1 includes a first refrigerant circuit 10 through which a refrigerant circulates. The first refrigerant circuit 10 includes a first intermediate heat exchanger 9 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with a heat transfer medium flowing therein, and an air heat exchanger 13 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with air. That is, the heat source unit 1 includes the first refrigerant circuit 10 through which a refrigerant circulates, the first intermediate heat exchanger 9 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with a heat transfer medium flowing therein, and the air heat exchanger 13 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with air.

[0015] The heat source unit 1 has a first refrigerant circuit 10 through which a refrigerant circulates. The first refrigerant circuit 10 is configured such that a first compressor 12, a first flow switching device 6, an air heat exchanger 13, a heat source-side flow control valve 7, and a first intermediate heat exchanger 9 are connected in this order by refrigerant piping. Note that the first refrigerant circuit 10 may include other components in addition to the above-described components, or may omit some components.

[0016] The first compressor 12 draws in low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges high-temperature, high-pressure refrigerant. The first compressor 12 is, for example, an inverter compressor. When the first compressor 12 is an inverter compressor, the operating frequency may be changed arbitrarily using an inverter circuit or the like to change the refrigerant discharge capacity per unit time. In this case, the operation of the inverter circuit is controlled by the control device 40. The refrigerant discharged from the first compressor 12 flows into the air heat exchanger 13 or the first intermediate heat exchanger 9 via the first flow switching device 6.

[0017] The first flow switching device 6 is, for example, a four-way valve and has a function of switching the flow path of the refrigerant. For example, during cooling operation of the air conditioning apparatus 100, the first flow switching device 6 switches the refrigerant flow path to connect the refrigerant discharge side of the first compressor 12 to the air heat exchanger 13 and to connect the refrigerant suction side of the first compressor 12 to the first intermediate heat exchanger 9. Meanwhile, during heating operation of the air conditioning apparatus 100, the first flow switching device 6 switches the refrigerant flow path to connect the refrigerant discharge side of the first compressor 12 to the first intermediate heat exchanger 9 and to connect the refrigerant suction side of the first compressor 12 to the air heat exchanger 13. The first flow switching device 6 may be configured by combining two-way or three-way valves. The first refrigerant circuit 10 can switch between cooling and heating operation by the first flow switching device 6.

[0018] For example, the air heat exchanger 13 functions as a condenser during cooling operation. Also, for example, the air heat exchanger 13 functions as an evaporator during heating operation. The air heat exchanger 13 draws in outdoor air using the heat source side blower 8, exchanges heat with the refrigerant flowing inside, and discharges the air to the outside.

[0019] The heat source side flow rate adjustment valve 7 is an expansion mechanism that reduces the pressure of the refrigerant flowing in the first refrigerant circuit 10 and expands it, and is configured, for example, by an electronic expansion valve whose opening degree is variably controlled.

[0020] The first intermediate heat exchanger 9 exchanges heat between the heat transfer medium and the refrigerant. The first intermediate heat exchanger 9 is a flow path of the heat transfer medium circuit 71 formed by the flow path of the first refrigerant circuit 10 and the connecting pipe 70. In other words, the first intermediate heat exchanger 9 is a component constituting the first refrigerant circuit 10 and a component constituting the heat transfer medium circuit 71 formed by the connecting pipe 70.

[0021] The first intermediate heat exchanger 9 functions as an evaporator during cooling operation, for example, and exchanges heat between the refrigerant flowing out from the heat source-side flow control valve 7 and the heat transfer medium, evaporating the refrigerant to vaporize it, and cooling the heat transfer medium. The first intermediate heat exchanger 9 functions as a condenser during heating operation, for example, and exchanges heat between the refrigerant flowing in from the first compressor 12 and the heat transfer medium, condensing the refrigerant to liquefy it or to form a two-phase gas-liquid state, and heating the heat transfer medium.

[0022] The first refrigerant circuit 10 contains, for example, R290, NH ３ The first refrigerant circuit 10 is filled with a flammable refrigerant such as olefin (R1234yf, R1234ze(E), R1123, R1132(E), etc.). This is because the heat source unit 1 is mainly installed outdoors, and a refrigerant that is flammable but has a small global warming effect is used. Note that the refrigerant filled in the first refrigerant circuit 10 is not limited to the above-mentioned refrigerants, and may be refrigerants that are currently commonly used in air conditioning, such as R410A or R32, R290, CO ２ NH ３ , olefins, mixtures thereof, and other types of refrigerants may also be used.

[0023] [Relay unit 2] The air conditioning apparatus 100 is equipped with a plurality of relay units 2 connected to at least one heat source unit 1. The relay units 2 are installed, for example, inside a building 200. Note that in Figures 1 and 2, the air conditioning apparatus 100 is equipped with two relay units 2, relay unit 2A and relay unit 2B, but the air conditioning apparatus 100 may also be equipped with three or more relay units 2. In the air conditioning apparatus 100 according to embodiment 1, the plurality of relay units 2 are arranged in parallel with one another in the flow path through which the heat transfer medium flows due to the first pump 11 described below.

[0024] 1 , each of the multiple relay units 2 has a main body 120 that houses devices therein. Each of the multiple relay units 2 has a first connection portion 91 and a second connection portion 92 that are connected to the multiple connection pipes 70 on the heat source unit 1 side, and a third connection portion 93, a fourth connection portion 94, a fifth connection portion 95, and a sixth connection portion 96 that are connected to the multiple connection pipes 70 on the multiple load devices 3 side. The first connection portion 91, the second connection portion 92, the third connection portion 93, the fourth connection portion 94, the fifth connection portion 95, and the sixth connection portion 96 are provided in the main body 120 and are portions in the main body 120 through which the heat transfer medium flows in and out.

[0025] Each of the multiple relay units 2 has a first flow path 211 that branches so that one end becomes the first connection portion 91 and the other end becomes the third connection portion 93 and the fourth connection portion 94. Each of the multiple relay units 2 also has a second flow path 212 that branches so that one end becomes the second connection portion 92 and the other end becomes the fifth connection portion 95 and the sixth connection portion 96 via the second intermediate heat exchanger 28.

[0026] Each of the multiple relay units 2 has a third flow path 213 that branches at one end thereof to form a first inlet / outlet 29a for the heat transfer medium in the third intermediate heat exchanger 29 and at the other end thereof to form a third connection part 93 and a fourth connection part 94. Furthermore, each of the multiple relay units 2 has a fourth flow path 214 that branches at one end thereof to form a second inlet / outlet 29b for the heat transfer medium in the third intermediate heat exchanger 29 and at the other end thereof to form a fifth connection part 95 and a sixth connection part 96.

[0027] The air conditioning device 100 has a bypass flow path 78 in the relay unit 2 that forms a flow path such that the heat transfer medium flowing in from the first connection part 91 passes through the second intermediate heat exchanger 28 without passing through the load device 3, and after passing through the second intermediate heat exchanger 28, flows out from the second connection part 92.

[0028] One end of the bypass flow path 78 is connected to a portion of the first flow path 211 between the first connection part 91 and the first heat medium flow switching device 60a and the second heat medium flow switching device 60b. The other end of the bypass flow path 78 is connected to a portion of the second flow path 212 between the second intermediate heat exchanger 28 and the third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d.

[0029] The bypass flow path 78 is provided with a heat medium bypass valve 25. The heat medium bypass valve 25 is configured as, for example, a two-way valve, and its opening and closing is controlled by the control device 40. The heat medium bypass valve 25 may be configured as, for example, a two-way valve whose valve opening (opening area) can be controlled. The heat medium bypass valve 25 controls the flow of the heat transfer medium flowing in and out of the load-side heat exchanger 30 of the load device 3 by controlling its opening and closing. The bypass flow path 78 has the heat medium bypass valve 25, and adjusts the flow rate of the heat transfer medium.

[0030] The first flow path 211, the second flow path 212, the third flow path 213, the fourth flow path 214, and the bypass flow path 78 form a flow path through which the heat transfer medium flows inside the relay unit 2. The first flow path 211, the second flow path 212, the third flow path 213, the fourth flow path 214, and the bypass flow path 78 form a part of the heat transfer medium circuit 71 inside the relay unit 2.

[0031] In the air conditioning apparatus 100 according to the first embodiment, the first connector 91 and the heat source unit 1 are connected by the connection pipe 70 in the first flow path 211 of the multiple relay units 2 so that the heat transfer medium flows from the first connector 91 side toward the third connector 93 and fourth connector 94 side. Also, in the air conditioning apparatus 100 according to the first embodiment, the second connector 92 and the heat source unit 1 are connected by the connection pipe 70 in the second flow path 212 so that the heat transfer medium flows from the fifth connector 95 and sixth connector 96 side toward the second connector 92 side.

[0032] All of the multiple relay units 2 include a second refrigerant circuit 20 through which a refrigerant circulates. The second refrigerant circuit 20 includes a second intermediate heat exchanger 28 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 20 and a heat transfer medium flowing therethrough, and a third intermediate heat exchanger 29 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 20 and the heat transfer medium flowing therethrough. The relay unit 2 includes the second refrigerant circuit 20 through which a refrigerant circulates, the second intermediate heat exchanger 28 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 20 and the heat transfer medium flowing therethrough, and the third intermediate heat exchanger 29 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 20 and the heat transfer medium flowing therethrough. The relay unit 2 is connected to a flow path formed by a plurality of connection pipes 70, and includes a plurality of heat medium flow path switching devices 60 that switch the flow path of the heat transfer medium.

[0033] In the air conditioning apparatus 100, the flow path of the heat transfer medium is switched to form a first heat medium circuit 75, a second heat medium circuit 76, and a third heat medium circuit 77. In the air conditioning apparatus 100, the flow path of the heat transfer medium is switched to form the above circuits by a first heat medium flow switching device 60a, a second heat medium flow switching device 60b, a third heat medium flow switching device 60c, a fourth heat medium flow switching device 60d, and a heat medium bypass valve 25.

[0034] As described above, the relay unit 2 has the second refrigerant circuit 20 through which the refrigerant circulates. The second refrigerant circuit 20 is configured such that a second compressor 22, a second flow switching device 26, a second intermediate heat exchanger 28, a relay unit flow control valve 27, and a third intermediate heat exchanger 29 are connected in this order by refrigerant piping. Note that the second refrigerant circuit 20 may include other components in addition to the above-described components, or may omit some components.

[0035] The second compressor 22 draws in low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges high-temperature, high-pressure refrigerant. The second compressor 22 is, for example, an inverter compressor and has basically the same configuration as the first compressor 12. The refrigerant discharged from the second compressor 22 flows into the second intermediate heat exchanger 28 or the third intermediate heat exchanger 29 via the second flow switching device 26.

[0036] The second flow path switching device 26 is, for example, a four-way valve and has a function of switching the flow path of the refrigerant. The second flow path switching device 26 basically has the same configuration as the first flow path switching device 6. For example, during heating operation of the load device 3, the second flow path switching device 26 switches the refrigerant flow path so as to connect the refrigerant discharge side of the second compressor 22 to the third intermediate heat exchanger 29 and to connect the refrigerant suction side of the second compressor 22 to the second intermediate heat exchanger 28.

[0037] For example, during cooling operation of the load device 3, the second flow switching device 26 switches the refrigerant flow path so as to connect the refrigerant discharge side of the second compressor 22 to the second intermediate heat exchanger 28 and to connect the refrigerant suction side of the second compressor 22 to the third intermediate heat exchanger 29. The second flow switching device 26 may be configured by combining two-way valves or three-way valves. The second refrigerant circuit 20 can switch between cooling and heating operation by the second flow switching device 26.

[0038] The relay flow rate adjustment valve 27 is an expansion mechanism that reduces the pressure of the refrigerant circulating in the second refrigerant circuit 20 and expands it, and is configured, for example, by an electronic expansion valve whose opening degree is variably controlled.

[0039] The second intermediate heat exchanger 28 exchanges heat between the heat transfer medium and the refrigerant. The second intermediate heat exchanger 28 is a flow path of the heat transfer medium circuit 71 formed by the flow path of the second refrigerant circuit 20 and the connecting pipe 70. In other words, the second intermediate heat exchanger 28 is a component of the second refrigerant circuit 20 and a component of the heat transfer medium circuit 71 formed by the connecting pipe 70. In the second intermediate heat exchanger 28 shown in FIG. 2 , particularly when functioning as a condenser, it is preferable to configure the pipes so that the refrigerant circulating through the second refrigerant circuit 20 and the heat transfer medium circulating through the heat transfer medium circuit 71 flow in counter directions to increase the heat exchange rate in the second intermediate heat exchanger 28.

[0040] When functioning as a condenser, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through the connecting pipe 70, condenses the refrigerant to liquefy or to form a gas-liquid two-phase state, and heats the heat transfer medium. When functioning as a condenser, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through the first heat medium circuit 75 or the third heat medium circuit 77 described below, condenses the refrigerant to liquefy or to form a gas-liquid two-phase state, and heats the heat transfer medium.

[0041] When functioning as an evaporator, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing out from the relay unit flow control valve 27 and the heat transfer medium circulating through the connection pipe 70, evaporating and vaporizing the refrigerant and cooling the heat transfer medium. When functioning as an evaporator, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing out from the relay unit flow control valve 27 and the heat transfer medium circulating through the first heat medium circuit 75 or the third heat medium circuit 77 described below, evaporating and vaporizing the refrigerant and cooling the heat transfer medium.

[0042] The third intermediate heat exchanger 29 exchanges heat between the heat transfer medium and the refrigerant. The third intermediate heat exchanger 29 is a flow path of the heat transfer medium circuit 71 formed by the flow path of the second refrigerant circuit 20 and the connecting piping 70. In other words, the third intermediate heat exchanger 29 is a component of the second refrigerant circuit 20 and a component of the heat transfer medium circuit 71 formed by the connecting piping 70. In the third intermediate heat exchanger 29 shown in FIG. 2 , particularly when functioning as a condenser, it is preferable to configure the piping so that the refrigerant circulating through the second refrigerant circuit 20 and the heat transfer medium circulating through the heat transfer medium circuit 71 flow in counter directions to increase the heat exchange rate in the third intermediate heat exchanger 29.

[0043] When functioning as an evaporator, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing out from the relay unit flow control valve 27 and the heat transfer medium circulating through the connecting pipe 70, evaporating and vaporizing the refrigerant and cooling the heat transfer medium. When functioning as an evaporator, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing out from the relay unit flow control valve 27 and the heat transfer medium circulating through a second heat medium circuit 76 described below, evaporating and vaporizing the refrigerant and cooling the heat transfer medium.

[0044] When functioning as a condenser, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through the connecting pipe 70, condenses the refrigerant to liquefy or to form a gas-liquid two-phase mixture, and heats the heat transfer medium. When functioning as a condenser, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through a second heat medium circuit 76 described later, condenses the refrigerant to liquefy or to form a gas-liquid two-phase mixture, and heats the heat transfer medium.

[0045] The second refrigerant circuit 20 is filled with a non-flammable or slightly flammable refrigerant, such as R410A, R32, olefin, or a mixture of these refrigerants. This is because the relay unit 2 is mainly installed indoors. The refrigerant filled in the second refrigerant circuit 20 is not limited to the above refrigerants, and may be any refrigerant commonly used in air conditioners today, such as R410A or R32, R290, CO ２ NH ３ The refrigerant sealed in the second refrigerant circuit 20 is, in consideration of safety, R290, NH ３ A flammable refrigerant such as an olefin may be enclosed.

[0046] The amount of refrigerant circulating through the first refrigerant circuit 10 is greater than the amount of refrigerant circulating through the second refrigerant circuit 20. The amount of refrigerant charged in the first refrigerant circuit 10 is, for example, 5 kg or less. The amount of refrigerant charged in the second refrigerant circuit 20 is, for example, less than 1 kg, which is the standard for using a flammable refrigerant indoors. The first refrigerant circuit 10 is mainly used for load devices 3 with heavy operating loads. In other words, in order to improve operating efficiency, the air conditioning apparatus 100 has a greater amount of refrigerant circulating through the first refrigerant circuit 10 than the amount of refrigerant circulating through the second refrigerant circuit 20.

[0047] In the air conditioning apparatus 100 pertaining to Embodiment 1, as an example, the second refrigerant circuit 20 in the relay unit 2 is operated, and the heat transfer medium flowing out from the heat source unit 1 is sent to the load device 3 without passing through the second intermediate heat exchanger 28 and the third intermediate heat exchanger 29 of the second refrigerant circuit 20. In the air conditioning apparatus 100 pertaining to Embodiment 1, the heat transfer medium returning from the load device 3 passes through the second intermediate heat exchanger 28 and returns to the heat source unit 1, and the circulating water of the heat source unit 1 is used as a heat source. The heat transfer medium passing through the third intermediate heat exchanger 29 of the second refrigerant circuit 20 circulates only between the relay unit 2 and the load device 3. Note that if the air conditioning apparatus 100 is a chiller type, the second refrigerant circuit 20 in the relay unit 2 is stopped, and the heat transfer medium from the heat source unit 1 is sent to the load device 3 and returned to the heat source unit 1.

[0048] The relay unit 2 has a plurality of heat medium flow switching devices 60. The plurality of heat medium flow switching devices 60 are provided in the relay unit 2 at an outflow side of the heat transfer medium flowing from the relay unit 2 to the plurality of load devices 3, and at an inflow side of the heat transfer medium flowing from the plurality of load devices 3 to the relay unit 2. The heat medium flow switching devices 60 are formed, for example, by a three-way valve, and opening and closing thereof is controlled by the control device 40 or by a person. The flow paths of the heat medium flow switching devices 60 can be switched by the control device 40 or by a person.

[0049] The heat medium flow switching device 60 may be configured with a two-way valve or the like. Furthermore, the heat medium flow switching device 60 may be configured with, for example, a valve whose opening degree (opening area) can be controlled. In the air conditioning apparatus 100, the flow path of the heat transfer medium flowing in and out of the relay unit 2 is controlled by controlling the opening and closing of the heat medium flow switching device 60 provided in the relay unit 2.

[0050] In the relay unit 2, the plurality of heat medium flow switching devices 60 are configured by four valves: a first heat medium flow switching device 60a, a second heat medium flow switching device 60b, a third heat medium flow switching device 60c, and a fourth heat medium flow switching device 60d. The number of heat medium flow switching devices 60 is not limited to four. The number of heat medium flow switching devices 60 in the relay unit 2 may be two or more than four depending on the number of load devices 3 connected to the relay unit 2.

[0051] The first heat medium flow switching device 60a is provided at the junction of one branch of the first flow path 211 and one branch of the third flow path 213, and switches the flow path of the heat transfer medium flowing through the third connection part 93. The second heat medium flow switching device 60b is provided at the junction of the other branch of the first flow path 211 and the other branch of the third flow path 213, and switches the flow path of the heat transfer medium flowing through the fourth connection part 94. The third heat medium flow switching device 60c is provided at the junction of one branch of the second flow path 212 and one branch of the fourth flow path 214, and switches the flow path of the heat transfer medium flowing through the fifth connection part 95. The fourth heat medium flow switching device 60d is provided at the junction of the other branch of the second flow path 212 and the other branch of the fourth flow path 214, and switches the flow path of the heat transfer medium flowing through the sixth connection part 96.

[0052] The first heat medium flow switching device 60a and the second heat medium flow switching device 60b of the relay unit 2 are arranged downstream of the second pump 21 in the flow direction of the heat transfer medium formed by the second pump 21, which will be described later. The first heat medium flow switching device 60a and the second heat medium flow switching device 60b are arranged downstream of the third intermediate heat exchanger 29 in the flow direction of the heat transfer medium formed by the second pump 21, which will be described later. The first heat medium flow switching device 60a and the second heat medium flow switching device 60b are arranged in parallel in the flow path in which the heat transfer medium formed by the second pump 21 flows.

[0053] The first heat medium flow switching device 60a and the second heat medium flow switching device 60b are arranged downstream of the first pump 11 in the flow direction of the heat transfer medium formed by the first pump 11, which will be described later. The first heat medium flow switching device 60a and the second heat medium flow switching device 60b are arranged downstream of the first intermediate heat exchanger 9 in the flow of the heat transfer medium caused by the first pump 11. The first heat medium flow switching device 60a and the second heat medium flow switching device 60b are arranged in parallel in the flow path in which the heat transfer medium caused by the first pump 11 flows.

[0054] The first heat medium flow switching device 60a and the second heat medium flow switching device 60b are connected at their upstream sides to the outlet side of the first intermediate heat exchanger 9 and the outlet side of the third intermediate heat exchanger 29 by the connecting piping 70 and the internal flow paths of the relay unit 2.

[0055] The first heat medium flow switching device 60a and the second heat medium flow switching device 60b of the relay unit 2 are connected to the load-side heat exchanger 30 of the load device 3. The first heat medium flow switching device 60a and the second heat medium flow switching device 60b of the relay unit 2 are arranged upstream of the load-side heat exchanger 30 in the flow direction of the heat transfer medium formed by the first pump 11 or the second pump 21. In the flow of the heat transfer medium by the first pump 11 or the second pump 21, the downstream portion of the heat medium flow switching device 60 is connected to the upstream portion of the load-side heat exchanger 30.

[0056] The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d of the relay unit 2 are arranged upstream of the second pump 21 in the flow direction of the heat transfer medium formed by the second pump 21 (described later). The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d are arranged upstream of the third intermediate heat exchanger 29 in the flow direction of the heat transfer medium formed by the second pump 21 (described later). The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d are arranged in parallel in the flow path in which the heat transfer medium formed by the second pump 21 flows.

[0057] The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d are arranged upstream of the first pump 11 in the flow direction of the heat transfer medium formed by the first pump 11, which will be described later. The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d are arranged upstream of the second intermediate heat exchanger 28 in the flow of the heat transfer medium caused by the first pump 11. The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d are arranged in parallel in the flow path in which the heat transfer medium caused by the first pump 11 flows.

[0058] The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d are connected at their downstream sides to the inlet side of the third intermediate heat exchanger 29 and the inlet side of the second intermediate heat exchanger 28 by the connecting pipe 70 and the internal flow path of the relay unit 2.

[0059] The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d of the relay unit 2 are connected to the load-side heat exchanger 30 of the load device 3. The third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d of the relay unit 2 are arranged downstream of the load-side heat exchanger 30 in the flow direction of the heat transfer medium formed by the first pump 11 or the second pump 21. In the flow of the heat transfer medium by the first pump 11 or the second pump 21, the upstream portion of the heat medium flow switching device 60 is connected to the downstream portion of the load-side heat exchanger 30.

[0060] [Load Device 3] The air conditioning apparatus 100 has a plurality of load devices 3 connected to a plurality of relay units 2. The load devices 3 are, for example, indoor units. The load devices 3 are installed, for example, inside a building 200. Note that in FIG. 2 , the air conditioning apparatus 100 has two load devices 3, load device 3A and load device 3B, connected to the relay unit 2, but the number of load devices 3 connected to the relay unit 2 may be three or more.

[0061] The load device 3 has a load-side heat exchanger 30 and a load-side blower 31. The load device 3 passes air in the indoor space through the load-side heat exchanger 30, generating a flow of air that is returned to the indoor space. The load-side heat exchanger 30 is, for example, a fin-tube heat exchanger that exchanges heat between the indoor air in the indoor space supplied from the load-side blower 31 and a heat transfer medium.

[0062] During cooling operation, the load-side heat exchanger 30 cools the indoor space by passing a heat transfer medium that is colder than the air through the heat transfer tubes of the load-side heat exchanger 30. On the other hand, during heating operation, the load-side heat exchanger 30 heats the indoor space by passing a heat transfer medium that is warmer than the air through the heat transfer tubes of the load-side heat exchanger 30. Although not shown, the load device 3 may have a flow rate adjustment device that adjusts the flow rate of the heat transfer medium flowing into the load-side heat exchanger 30.

[0063] [Connection piping 70] The air conditioning apparatus 100 includes a plurality of connection piping 70 that connects at least one heat source unit 1, a plurality of relay units 2, and a plurality of load devices 3. The connection piping 70 connects the heat source unit 1 and the relay unit 2. The connection piping 70 connects the relay unit 2 and the load devices 3. The connection piping 70 constitutes a heat transfer medium circuit 71 through which the heat transfer medium flows.

[0064] A heat transfer medium flows through a heat transfer medium circuit 71 formed by connection pipes 70. The heat transfer medium is, for example, water, brine, or a mixture of brine and water. In the air conditioning apparatus 100, the heat source unit 1 and the relay unit 2 are connected by two connection pipes 70, and the relay unit 2 and each of the multiple load devices 3 are connected by two connection pipes 70.

[0065] [Control device 40] The control device 40 controls the overall operation of the air conditioning apparatus 100. The control device 40 controls at least one heat source unit 1, multiple relay units 2, and multiple load devices 3. Specifically, the control device 40 controls the drive frequency of the compressor, the rotation speed of the blower, switching of the flow path switching device, the opening degree of the expansion mechanism, the opening degree of the flow path switching valve, and the drive frequency of the pump. The control device 40 is composed of a computer equipped with a memory that stores data and programs required for control and a CPU that executes programs, dedicated hardware such as an ASIC or FPGA, or both.

[0066] The air conditioning apparatus 100 has a first refrigerant temperature sensor 41, a second refrigerant temperature sensor 42, a first heat medium temperature sensor 43, and a second heat medium temperature sensor 44. The first refrigerant temperature sensor 41 and the second refrigerant temperature sensor 42 detect the temperature of the refrigerant flowing through the second refrigerant circuit 20. The first refrigerant temperature sensor 41 and the second refrigerant temperature sensor 42 detect the temperature of the refrigerant flowing into the second intermediate heat exchanger 28 or the temperature of the refrigerant flowing out of the second intermediate heat exchanger 28.

[0067] The first heat medium temperature sensor 43 and the second heat medium temperature sensor 44 detect the temperature of the heat transfer medium flowing through the heat transfer medium circuit 71, such as the first heat medium circuit 75 or the third heat medium circuit 77. The first heat medium temperature sensor 43 and the second heat medium temperature sensor 44 detect the temperature of the heat transfer medium flowing into the second intermediate heat exchanger 28 or the temperature of the heat transfer medium flowing out of the second intermediate heat exchanger 28. The refrigerant temperatures and heat transfer medium temperatures detected by the first refrigerant temperature sensor 41, the second refrigerant temperature sensor 42, the first heat medium temperature sensor 43, and the second heat medium temperature sensor 44 are used by the control device 40 to control the various devices that make up the air conditioning apparatus 100.

[0068] [Flow Rate Adjustment Mechanism 80] Each of the multiple relay units 2 has a flow rate adjustment mechanism 80 that adjusts the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 between the multiple relay units 2. The flow rate adjustment mechanism 80 adjusts the flow rate of the heat transfer medium flowing into the relay unit 2. The flow rate adjustment mechanism 80 adjusts the flow rate of the heat transfer medium flowing through each of the multiple relay units 2, for example, in accordance with the thermal load of the multiple load devices 3. The greater the thermal load, the greater the flow rate of the heat transfer medium required. The flow rate adjustment mechanism 80 adjusts the flow rate of the heat transfer medium to correspond to the required heating and cooling capacity. The flow rate adjustment mechanism 80 is controlled, for example, by the control device 40. Note that the flow rate adjustment mechanism 80 may also be controlled manually.

[0069] In the air conditioning apparatus 100 of embodiment 1, the flow rate adjustment mechanism 80 includes a first heat medium flow switching device 60a, a second heat medium flow switching device 60b, a third heat medium flow switching device 60c, a fourth heat medium flow switching device 60d, and a bypass flow path 78 having a heat medium bypass valve 25.

[0070] [Example of a heat transfer medium circuit 71 of the air conditioning apparatus 100] The air conditioning apparatus 100 is formed with at least one or more of at least one first heat medium circuit 75, at least one second heat medium circuit 76, and at least one third heat medium circuit 77. The first heat medium circuit 75 constitutes a circuit through which the heat transfer medium circulates from the heat source unit 1, which is an outdoor unit, to the load device 3, which is an indoor unit. The second heat medium circuit 76 constitutes a circuit through which the heat transfer medium circulates from the relay unit 2 to the load device 3, which is an indoor unit. The third heat medium circuit 77 constitutes a circuit through which the heat transfer medium circulates from the heat source unit 1, which is an outdoor unit, to the relay unit 2. The first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77 constitute part of the heat transfer medium circuit 71.

[0071] The first heat medium circuit 75 connects at least one heat source unit 1, at least one of the multiple relay units 2, and at least one of the multiple load devices 3 via multiple connection pipes 70. The air conditioning device 100 is configured so that a heat transfer medium circulates through the first heat medium circuit 75. The air conditioning device 100 is configured so that the heat transfer medium circulates between the heat source unit 1 and the load device 3 via the relay unit 2 in the first heat medium circuit 75.

[0072] The first heat medium circuit 75 connects the first intermediate heat exchanger 9, at least one of the load side heat exchangers 30 of the multiple load devices 3, and at least one second intermediate heat exchanger 28 via multiple connection pipes 70. In the air conditioning apparatus 100, the first intermediate heat exchanger 9, the load side heat exchanger 30, and the second intermediate heat exchanger 28 are connected via the connection pipes 70 to form the first heat medium circuit 75 through which the heat transfer medium circulates.

[0073] The second heat medium circuit 76 connects at least one of the multiple relay units 2 and at least one of the multiple load devices 3 via multiple connection pipes 70. The air conditioning device 100 is configured so that the heat transfer medium circulates through the second heat medium circuit 76. The air conditioning device 100 is configured so that the heat transfer medium circulates between the relay unit 2 and the load device 3 in the second heat medium circuit 76.

[0074] In the second heat medium circuit 76, the third intermediate heat exchanger 29 and at least one of the load-side heat exchangers 30 of the multiple load devices 3 are connected by multiple connection pipes 70. In the air conditioning apparatus 100, the third intermediate heat exchanger 29 and the load-side heat exchanger 30 are connected by the connection pipes 70 to form the second heat medium circuit 76 through which the heat transfer medium circulates.

[0075] The third heat medium circuit 77 connects at least one heat source unit 1 and at least one of the multiple relay units 2 via multiple connection pipes 70. The air conditioning device 100 is configured so that a heat transfer medium circulates through the third heat medium circuit 77. The air conditioning device 100 is configured so that a heat transfer medium circulates between the heat source unit 1 and the relay unit 2 in the third heat medium circuit 77. A portion of the flow path of the third heat medium circuit 77 overlaps with the first heat medium circuit 75.

[0076] The third heat medium circuit 77 connects the first intermediate heat exchanger 9 and at least one second intermediate heat exchanger 28 via a plurality of connecting pipes 70. In the air conditioning apparatus 100, the first intermediate heat exchanger 9 and the second intermediate heat exchanger 28 are connected via the connecting pipes 70 to form the third heat medium circuit 77 through which the heat transfer medium circulates. The third heat medium circuit 77 includes a bypass flow path 78 having a heat medium bypass valve 25, which will be described later. In the third heat medium circuit 77, the heat transfer medium passes through the first intermediate heat exchanger 9, the second intermediate heat exchanger 28, and the heat medium bypass valve 25, and circulates between the heat source unit 1 and the relay unit 2.

[0077] The plurality of heat medium flow switching devices 60 and the heat medium bypass valves 25 are connected to the plurality of connection pipes 70 and are used to switch the flow path of the heat transfer medium to configure one or more of the first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77. In other words, the plurality of heat medium flow switching devices 60 and the heat medium bypass valves 25 are used to switch the flow path of the heat transfer medium circuit 71.

[0078] The heat transfer medium circuit 71 constituting the first heat medium circuit 75 and the second heat medium circuit 76 is provided with a plurality of heat medium flow switching devices 60 that switch the flow path of the heat transfer medium flowing into the plurality of load devices 3 between the first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77. The heat transfer medium circuit 71 constituting the third heat medium circuit 77 is provided with a heat medium bypass valve 25 that switches the flow path of the heat transfer medium flowing into the plurality of load devices 3 between the first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77.

[0079] The first heat medium circuit 75 is provided with a first pump 11 that circulates the heat transfer medium. The first pump 11 is one of the devices that make up the first heat medium circuit 75, and is provided in the heat source unit 1, as an example. The first pump 11 sucks the heat transfer medium in the first heat medium circuit 75, applies pressure to it, and sends it out to circulate. The capacity of the first pump 11 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the first pump 11 by arbitrarily changing the drive frequency based on instructions from the control device 40.

[0080] In Fig. 2 , the first pump 11 is provided in the heat source unit 1, but the installation location of the first pump 11 is not limited to the heat source unit 1. The first pump 11 may be provided in, for example, the relay unit 2. Furthermore, the first pump 11 may be provided in each of the heat source unit 1 and the relay unit 2. In Fig. 2 , the number of first pumps 11 is one, but the number of first pumps 11 is not limited to one and may be multiple. For example, the first pump 11 may be provided in each of multiple relay units 2.

[0081] The second heat medium circuit 76 is provided with a second pump 21 that circulates the heat transfer medium. The second pump 21 is one of the devices that make up the second heat medium circuit 76, and is provided in the relay unit 2, for example. The second pump 21 sucks the heat transfer medium in the second heat medium circuit 76, applies pressure to it, and sends it out to circulate. The capacity of the second pump 21 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the second pump 21 by arbitrarily changing the drive frequency based on instructions from the control device 40.

[0082] The second pump 21 has a smaller flow rate or head than the first pump 11. The second heat medium circuit 76 connects the relay unit 2 and the load device 3, and the length of the flow path of the heat transfer medium circuit 71 is shorter than that of the first heat medium circuit 75, which also connects the heat source unit 1, and the pressure loss is not as large. Making the second pump 21 smaller than the first pump 11 reduces costs and the burden of installation work. The second pump 21 may have the same flow rate or head as the first pump 11.

[0083] The size of the pump is determined, for example, by the transport distance of the heat transport medium. The size of the pump is determined, for example, by the electric input W = ΔP × V, where ΔP is the pressure loss (corresponding to the pump head) [unit: kPa, for example] in the heat transport medium circuit 71, and V is the volumetric flow rate [unit: m ３ / s].

[0084] In the air conditioning apparatus 100, for example, in one or more of the multiple relay units 2, heat exchange occurs between the heat transfer medium flowing through the second intermediate heat exchanger 28 and the refrigerant in the second refrigerant circuit 20, and heat exchange occurs between the heat transfer medium flowing through the third intermediate heat exchanger 29 and the refrigerant in the second refrigerant circuit 20. In the relay unit 2, a heat transfer medium having a temperature range different from that of the heat transfer medium flowing through the second intermediate heat exchanger 28 is generated in the third intermediate heat exchanger 29 via the refrigerant flowing through the second refrigerant circuit 20 by the heat transfer medium flowing through the second intermediate heat exchanger 28.

[0085] In the air conditioning apparatus 100, the second refrigerant circuit 20 of the relay unit 2 removes heat from a first heat transfer medium flowing through one of two connection pipes 70 connecting the heat source unit 1 and the relay unit 2. The second refrigerant circuit 20 of the relay unit 2 provides heat to a second heat transfer medium flowing through one of two connection pipes 70 connecting the relay unit 2 and the load devices 3, and provides heat to the second heat transfer medium flowing through at least one load-side heat exchanger 30 of the multiple load devices 3.

[0086] Alternatively, in the air conditioning apparatus 100, the second refrigerant circuit 20 of the relay unit 2 provides heat to a first heat transfer medium flowing through one of two connection pipes 70 connecting the heat source unit 1 and the relay unit 2. The second refrigerant circuit 20 of the relay unit 2 removes heat from a second heat transfer medium flowing through one of two connection pipes 70 connecting the relay unit 2 and the load devices 3, and removes heat from the second heat transfer medium flowing through at least one load-side heat exchanger 30 of the multiple load devices 3.

[0087] In the air conditioning apparatus 100, the second refrigerant circuit 20 of the relay unit 2 changes the temperatures of the first heat transfer medium and the second heat transfer medium. The first heat transfer medium is the heat transfer medium that flows through the first heat medium circuit 75 or the third heat medium circuit 77, and the second heat transfer medium is the heat transfer medium that flows through the second heat medium circuit 76.

[0088] Next, the operating behavior of the air conditioning apparatus 100 during various operations will be described. The air conditioning apparatus 100 has four operating modes: cooling operation mode, heating operation mode, cooling-dominated operation mode, and heating-dominated operation mode. The heat source unit 1, relay unit 2, and load device 3 each have a cooling operation mode, a heating operation mode, and an operation-stop mode. Note that the flow of the heat transfer medium in the various operating modes in the following description is an example.

[0089] The cooling operation mode of the air conditioning apparatus 100 is an operation mode in which only cooling is performed by the load device 3, and any one of the multiple load devices 3 is either cooling or stopped. The heating operation mode of the air conditioning apparatus 100 is an operation mode in which only heating is performed by the load device 3, and any one of the multiple load devices 3 is either heating or stopped.

[0090] The cooling-dominated operation mode of the air conditioning apparatus 100 is an operation mode in which cooling or heating can be selected for each of multiple load devices 3, and in simultaneous cooling and heating operation in which both load devices 3 performing cooling and load devices 3 performing heating are present, the cooling load is greater than the heating load. In the cooling-dominated operation mode of the air conditioning apparatus 100, the temperature of the heat transfer medium supplied from the heat source unit 1 to the relay unit 2 is lower than the temperature of the intake air of the load devices 3 serving as indoor units, and there are one or more load devices 3 performing heating operation via the relay unit 2. The cooling load is determined, for example, by multiplying the number of indoor units performing cooling operation by the size (capacity and capacity) of the indoor units performing cooling operation. The heating load is determined, for example, by multiplying the number of indoor units performing heating operation by the size (capacity and capacity) of the indoor units performing heating operation.

[0091] The heating-dominated operation mode of the air conditioning apparatus 100 is an operation mode in which heating or cooling can be selected for each of multiple load devices 3, and in simultaneous cooling and heating operation in which load devices 3 performing cooling and load devices 3 performing heating exist simultaneously, the heating load is greater than the cooling load. In the heating-dominated operation mode of the air conditioning apparatus 100, the temperature of the heat transfer medium supplied from the heat source unit 1 to the relay unit 2 is higher than the temperature of the air sucked into the load devices 3 that are indoor units, and there are one or more load devices 3 performing cooling operation by the relay unit 2.

[0092] The operation mode of the air conditioning apparatus 100 is switched automatically by the control device 40 or switched by human operation. In the case of automatic operation by the control device 40, for example, the control device 40 sets the operation mode by observing the operating conditions in each room, such as the difference between the set temperature and the measured temperature in each room. Alternatively, the control device 40 detects the temperature of the heat transfer medium flowing through the heat transfer medium circuit 71 and compares the detected temperature with a threshold value to set the operation mode.

[0093] The control device 40 controls all operation modes of at least one heat source unit 1 to be the operation mode with the larger heat load of the overall system. The control device 40 may also control and operate at least one operation mode of multiple relay units 2 to be the operation mode with the smaller heat load of the overall system. For example, the control device 40 controls the supply water temperature of the heat source unit 1, which is an outdoor unit, to be the water temperature of the main operating side of the overall system, and controls the supply water temperature of the relay unit 2 to be the water temperature of the side that is not the main operating side of the overall system.

[0094] The operation mode of the heat source unit 1, which is the outdoor unit, operates in an operation mode that results in a larger thermal load on the entire system of the air conditioning apparatus 100. In other words, the first heat medium circuit 75 operates in an operation mode that results in a larger thermal load on the entire system of the air conditioning apparatus 100. The operation mode of the relay unit 2 operates in an operation mode that results in a smaller thermal load on the entire system of the air conditioning apparatus 100. In other words, the operation mode of the second heat medium circuit 76 operates in an operation mode that results in a smaller thermal load on the entire system of the air conditioning apparatus 100.

[0095] The heating-dominant operation mode and the cooling-dominant operation mode are switched when a preset condition is met, for example, when there is a change in the number of operating load devices 3 or the load balance of the load devices 3. The heating-dominant operation mode and the cooling-dominant operation mode do not have to be switched immediately when a preset condition is met when there is a change in the number of operating load devices 3 or the load balance of the load devices 3, but may be switched after continuing operation for a while and it becomes clear that the cooling / heating operation should be reversed.

[0096] In the cooling operation mode of the heat source unit 1, the heat source unit 1 generates a low-temperature heat transfer medium. The low-temperature heat transfer medium is, for example, a heat transfer medium at 10°C or below. The low-temperature heat transfer medium generated in the heat source unit 1 is sent to the relay unit 2 by the first pump 11. In the cooling operation mode of the heat source unit 1, the air heat exchanger 13 functions as a condenser, and the first intermediate heat exchanger 9 functions as an evaporator.

[0097] In the heating operation mode of the heat source unit 1, the heat source unit 1 generates a high-temperature heat transfer medium. The high-temperature heat transfer medium is, for example, a heat transfer medium at 40°C or higher. The high-temperature heat transfer medium generated in the heat source unit 1 is sent to the relay unit 2 by the first pump 11. In the heating operation mode of the heat source unit 1, the air heat exchanger 13 functions as an evaporator, and the first intermediate heat exchanger 9 functions as a condenser.

[0098] In the cooling operation mode of the relay unit 2, the relay unit 2 generates a low-temperature heat transfer medium. The low-temperature heat transfer medium is, for example, a heat transfer medium at 10°C or below. The low-temperature heat transfer medium generated in the relay unit 2 is sent to one or more of the multiple load devices 3 by the second pump 21. In the cooling operation mode of the relay unit 2, the second intermediate heat exchanger 28 functions as a condenser, and the third intermediate heat exchanger 29 functions as an evaporator.

[0099] In the heating operation mode of the relay unit 2, the relay unit 2 generates a high-temperature heat transfer medium. The high-temperature heat transfer medium is, for example, a heat transfer medium at 40°C or higher. The high-temperature heat transfer medium generated by the relay unit 2 is sent to one or more of the multiple load devices 3 by the second pump 21. In the heating operation mode of the relay unit 2, the second intermediate heat exchanger 28 functions as an evaporator, and the third intermediate heat exchanger 29 functions as a condenser.

[0100] In the operation stop mode of the relay unit 2, the operation of the second compressor 22 is stopped, and the operation of the second refrigerant circuit 20 is stopped.

[0101] In the cooling operation mode of the load device 3, heat exchange between the heat transfer medium and air is performed in the load-side heat exchanger 30, and cool air is supplied to the indoor space. In the heating operation mode of the load device 3, heat exchange between the heat transfer medium and air is performed in the load-side heat exchanger 30, and warm air is supplied to the indoor space.

[0102] In the cooling operation mode and the heating operation mode of the load device 3, the load-side blower 31 is in operation and air is supplied to the load-side heat exchanger 30. In the operation-stop mode of the load device 3, the heat transfer medium does not flow into the load-side heat exchanger 30 and heat exchange between the heat transfer medium and the air does not occur. In the operation-stop mode of the load device 3, the load-side blower 31 is in a stopped state.

[0103] (Cooling operation mode) Fig. 3 is a circuit diagram showing an example of the cooling operation mode of the air conditioning apparatus 100 according to embodiment 1. First, an example of the cooling operation mode of the air conditioning apparatus 100 will be described with reference to Fig. 3. Fig. 3 is a circuit diagram showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when cooling is performed by the load device 3. Note that the dashed arrows shown in Fig. 3 indicate an example of the flow of the heat transfer medium. Furthermore, the white color shown in the heat medium flow switching device 60 indicates a state in which the valve is open, and the black color shown in the heat medium flow switching device 60 indicates a state in which the valve is closed.

[0104] In the air conditioning apparatus 100 according to Embodiment 1, when the load device 3 is operated in the cooling operation mode, the heat source unit 1 is operated in the cooling operation mode, and the relay unit 2 is in the operation stop mode. That is, when the load device 3 is cooled, the air conditioning apparatus 100 according to Embodiment 1 stops the second refrigerant circuit 20 and operates the first refrigerant circuit 10 and the first heat medium circuit 75.

[0105] When cooling is performed by the load device 3, the air conditioning apparatus 100 opens and closes valves such as the first heat medium flow switching device 60a, the second heat medium flow switching device 60b, the third heat medium flow switching device 60c, and the fourth heat medium flow switching device 60d of the relay unit 2 so as to connect the relay unit 2 and the load device 3. When cooling is performed by the load device 3, the air conditioning apparatus 100 opens the valves of the heat medium flow switching devices 60 so that the heat transfer medium flows through the first heat medium circuit 75. When cooling is performed by the load device 3, the air conditioning apparatus 100 closes the valves of the heat medium flow switching devices 60 so that the heat transfer medium does not flow through the second heat medium circuit 76. The air conditioning apparatus 100 adjusts the number of times the heat medium flow switching devices 60 are opened and closed depending on the magnitude of the thermal load of the relay unit 2 and the load device 3.

[0106] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching device 6 and flows to the air heat exchanger 13, where it exchanges heat with air and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the heat source-side flow control valve 7 to become a low-pressure gas-liquid two-phase refrigerant, flows to the first intermediate heat exchanger 9, and exchanges heat with the heat transfer medium flowing in the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75, the third heat medium circuit 77, etc., to be evaporated and gasified. The gasified refrigerant passes through the first flow switching device 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0107] The heat transfer medium flowing through the first heat medium circuit 75 is cooled by the refrigerant flowing through the first intermediate heat exchanger 9 to become a low-temperature heat transfer medium, and then passes through the relay unit 2 and flows into the load-side heat exchanger 30 of the load device 3. The heat transfer medium that has flowed into the load-side heat exchanger 30 of the load device 3 is heated by heat exchange with the indoor air and flows out of the load device 3. The heated heat transfer medium that has flowed out of the load device 3 passes through the relay unit 2 and flows again into the first intermediate heat exchanger 9 of the heat source device 1.

[0108] The heat transfer medium that has flowed out of the first intermediate heat exchanger 9 passes through the first connection part 91 to flow into the relay unit 2, and then passes through the first heat medium flow switching device 60a and the third connection part 93 to flow out of the relay unit 2. The heat transfer medium that has flowed out of the relay unit 2 through the first heat medium flow switching device 60a and the third connection part 93 passes through the load-side heat exchanger 30 of the load device 3B and then flows out of the load device 3B. The heat transfer medium that has flowed out of the load device 3B passes through the sixth connection part 96 to flow into the relay unit 2, passes through the fourth heat medium flow switching device 60d and the second intermediate heat exchanger 28, and then passes through the second connection part 92 to flow out of the relay unit 2.

[0109] The heat transfer medium that has flowed out of the first intermediate heat exchanger 9 passes through the first connection part 91 to flow into the relay unit 2, and then passes through the second heat medium flow switching device 60b and the fourth connection part 94 to flow out of the relay unit 2. The heat transfer medium that has flowed out of the relay unit 2 through the second heat medium flow switching device 60b and the fourth connection part 94 passes through the load-side heat exchanger 30 of the load device 3A and then flows out of the load device 3A. The heat transfer medium that has flowed out of the load device 3A passes through the fifth connection part 95 to flow into the relay unit 2, passes through the third heat medium flow switching device 60c and the second intermediate heat exchanger 28, and then passes through the second connection part 92 to flow out of the relay unit 2.

[0110] (Heating operation mode) Fig. 4 is a circuit diagram showing an example of a heating operation mode in the air conditioning apparatus 100 according to embodiment 1. An example of a heating operation mode in the air conditioning apparatus 100 will be described with reference to Fig. 4. Fig. 4 is a circuit diagram showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when heating is performed by the load device 3. Note that the dashed arrows shown in Fig. 4 indicate an example of the flow of the heat transfer medium. Furthermore, the white color shown in the heat medium flow switching device 60 indicates a state in which the valve is open, and the black color shown in the heat medium flow switching device 60 indicates a state in which the valve is closed.

[0111] In the air conditioning apparatus 100 according to Embodiment 1, when the load device 3 is operated in the heating operation mode, the heat source unit 1 is operated in the heating operation mode, and the relay unit 2 is in the operation stop mode. That is, when the load device 3 is used for heating, the air conditioning apparatus 100 according to Embodiment 1 stops the second refrigerant circuit 20 and operates the first refrigerant circuit 10 and the first heat medium circuit 75.

[0112] When heating is performed by the load device 3, the air conditioning apparatus 100 opens and closes valves such as the first heat medium flow switching device 60a, the second heat medium flow switching device 60b, the third heat medium flow switching device 60c, and the fourth heat medium flow switching device 60d of the relay unit 2 so as to connect the relay unit 2 and the load device 3. When heating is performed by the load device 3, the air conditioning apparatus 100 opens the valves of the heat medium flow switching devices 60 so that the heat transfer medium flows through the first heat medium circuit 75. When heating is performed by the load device 3, the air conditioning apparatus 100 closes the valves of the heat medium flow switching devices 60 so that the heat transfer medium does not flow through the second heat medium circuit 76. The air conditioning apparatus 100 adjusts the number of times the heat medium flow switching devices 60 are opened and closed depending on the magnitude of the heat load of the relay unit 2 and the load device 3.

[0113] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching device 6 and flows into the first intermediate heat exchanger 9. The refrigerant that flows into the first intermediate heat exchanger 9 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75, the third heat medium circuit 77, etc., and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the heat source-side flow control valve 7 to become a low-pressure gas-liquid two-phase refrigerant, and flows into the air heat exchanger 13. The gas-liquid two-phase refrigerant that flows into the air heat exchanger 13 exchanges heat with air and is evaporated and gasified. The gasified refrigerant passes through the first flow switching device 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0114] The heat transfer medium flowing through the first heat medium circuit 75 is heated by the refrigerant flowing through the first intermediate heat exchanger 9 to become a high-temperature heat transfer medium, and then flows through the relay unit 2 into the load-side heat exchanger 30 of the load device 3. The heat transfer medium that has flowed into the load-side heat exchanger 30 of the load device 3 exchanges heat with the indoor air to be cooled, and then flows out of the load device 3. The cooled heat transfer medium that has flowed out of the load device 3 flows through the relay unit 2 again into the first intermediate heat exchanger 9 of the heat source device 1. The flow of the heat transfer medium inside the relay unit 2 is the same as in the cooling operation mode.

[0115] (Cooling-dominated operation mode) Fig. 5 is a circuit diagram showing an example of the cooling-dominated operation mode of the air conditioning apparatus 100 according to embodiment 1. An example of the cooling-dominated operation mode of the air conditioning apparatus 100 will be described with reference to Fig. 5. Fig. 5 is a circuit diagram showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when cooling and heating are performed by the load device 3. Note that the dashed arrows shown in Fig. 5 indicate an example of the flow of the heat transfer medium. Furthermore, the white color shown in the heat medium flow switching device 60 indicates a state in which the valve is open, and the black color shown in the heat medium flow switching device 60 indicates a state in which the valve is closed.

[0116] When the air conditioning apparatus 100 according to Embodiment 1 operates in the cooling-dominant operation mode, the heat source unit 1 operates in the cooling operation mode, and the relay unit 2 operates in the heating operation mode. In Fig. 5, the relay unit 2A and the relay unit 2B are in the heating operation mode, but depending on the state of the heat load, one or more of the multiple relay units 2 may be in a stopped state.

[0117] In the air conditioning apparatus 100, in the cooling-dominated operation mode, the operation modes are different between the heat source unit 1 and the multiple relay units 2. In the air conditioning apparatus 100, the temperature of the heat transfer medium sent from the heat source unit 1 to the multiple relay units 2 may differ from the temperature of the heat transfer medium sent from the multiple relay units 2 to one or more of the multiple relay units 2.

[0118] In the air conditioning apparatus 100, in the cooling-dominated operation mode, when the heat transfer medium sent from the heat source unit 1 to the relay unit 2 is chilled water, the heat transfer medium sent from the multiple relay units 2 to one or more of the multiple load devices 3 may be hot water. The heat transfer medium sent from the heat source unit 1 to the relay unit 2 here is the heat transfer medium cooled by the first refrigerant circuit 10. Furthermore, the heat transfer medium sent from the relay unit 2 to one or more of the multiple load devices 3 here is the heat transfer medium heated by the second refrigerant circuit 20.

[0119] In the cooling-dominated operation mode, the air conditioning apparatus 100 according to Embodiment 1 operates the first refrigerant circuit 10, the second refrigerant circuit 20, and the first heat medium circuit 75. In addition, in the cooling-dominated operation mode, the air conditioning apparatus 100 according to Embodiment 1 operates one or more of the second heat medium circuit 76 and the third heat medium circuit 77.

[0120] When the air conditioning apparatus 100 performs cooling using the load device 3B connected to the relay unit 2A, the heat medium flow switching device 60 is opened and closed so as to connect the first intermediate heat exchanger 9 and the load device 3B via the relay unit 2A. In the air conditioning apparatus 100, valves such as the first heat medium flow switching device 60a, the second heat medium flow switching device 60b, the third heat medium flow switching device 60c, and the fourth heat medium flow switching device 60d of the relay unit 2A are opened and closed.

[0121] When the air conditioning apparatus 100 performs cooling on the load device 3B connected to the relay unit 2A, it opens the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d so that the heat transfer medium flows through the first heat medium circuit 75. When the air conditioning apparatus 100 performs cooling on the load device 3B connected to the relay unit 2A, it closes the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d so that the heat transfer medium does not flow through the second heat medium circuit 76.

[0122] When the air conditioning apparatus 100 performs heating using the load device 3A connected to the relay unit 2A, the heat medium flow switching device 60 is opened and closed so as to connect the third intermediate heat exchanger 29 of the relay unit 2A to the load device 3A. The air conditioning apparatus 100 opens and closes valves such as the first heat medium flow switching device 60a, the second heat medium flow switching device 60b, the third heat medium flow switching device 60c, and the fourth heat medium flow switching device 60d of the relay unit 2A.

[0123] When the load device 3A connected to the relay unit 2A performs heating, the air conditioning apparatus 100 closes the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c to prevent the heat transfer medium from flowing through the first heat medium circuit 75. When the load device 3A connected to the relay unit 2A performs heating, the air conditioning apparatus 100 opens the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c to allow the heat transfer medium to flow through the second heat medium circuit 76.

[0124] When the air conditioning apparatus 100 performs heating using the load devices 3A and 3B of the relay unit 2B, the heat medium flow switching device 60 is opened and closed so as to connect the third intermediate heat exchanger 29 of the relay unit 2B to the load devices 3A and 3B. The air conditioning apparatus 100 opens and closes valves such as the first heat medium flow switching device 60a and the second heat medium flow switching device 60b, and the third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d of the relay unit 2B.

[0125] When the load device 3A connected to the relay unit 2B performs heating, the air conditioning device 100 closes the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c to prevent the heat transfer medium from flowing through the first heat medium circuit 75. When the load device 3A connected to the relay unit 2B performs heating, the air conditioning device 100 opens the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c to allow the heat transfer medium to flow through the second heat medium circuit 76.

[0126] When heating is performed by the load device 3B connected to the relay unit 2B, the air conditioning device 100 closes the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d to prevent the heat transfer medium from flowing through the first heat medium circuit 75. When heating is performed by the load device 3B connected to the relay unit 2B, the air conditioning device 100 opens the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d to allow the heat transfer medium to flow through the second heat medium circuit 76.

[0127] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching device 6 and flows to the air heat exchanger 13, where it exchanges heat with air and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the heat source-side flow control valve 7 to become a low-pressure gas-liquid two-phase refrigerant, flows to the first intermediate heat exchanger 9, and exchanges heat with the heat transfer medium flowing in the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75, the third heat medium circuit 77, etc., to be evaporated and gasified. The gasified refrigerant passes through the first flow switching device 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0128] The heat transfer medium flowing through the first heat medium circuit 75 is cooled by the refrigerant flowing through the first intermediate heat exchanger 9 to become a low-temperature heat transfer medium, and then flows into the load-side heat exchanger 30 of the load device 3B via the relay unit 2A. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3B is heated by heat exchange with the indoor air and flows out of the load device 3B. The heated heat transfer medium that flows out of the load device 3B flows again into the first intermediate heat exchanger 9 of the heat source device 1 via the relay unit 2A.

[0129] The heat transfer medium that has flowed out of the first intermediate heat exchanger 9 passes through the first connection part 91 to flow into the relay unit 2A, and then passes through the first heat medium flow switching device 60a and the third connection part 93 to flow out of the relay unit 2A. The heat transfer medium that has flowed out of the relay unit 2A through the first heat medium flow switching device 60a and the third connection part 93 passes through the load-side heat exchanger 30 of the load device 3B and then flows out of the load device 3B. The heat transfer medium that has flowed out of the load device 3B passes through the sixth connection part 96 to flow into the relay unit 2A, passes through the fourth heat medium flow switching device 60d and the second intermediate heat exchanger 28, and then passes through the second connection part 92 to flow out of the relay unit 2A.

[0130] In the second refrigerant circuit 20 of the relay unit 2A, high-temperature, high-pressure gas refrigerant discharged from the second compressor 22 passes through the second flow switching device 26 and flows into the third intermediate heat exchanger 29. The refrigerant that flows into the third intermediate heat exchanger 29 exchanges heat with the heat transfer medium flowing through the second heat medium circuit 76 and condenses and liquefies. The condensed and liquefied refrigerant is reduced in pressure by the relay unit flow control valve 27 to become a low-pressure gas-liquid two-phase refrigerant and flows into the second intermediate heat exchanger 28. The gas-liquid two-phase refrigerant that flows into the second intermediate heat exchanger 28 exchanges heat with the heat transfer medium flowing through the first heat medium circuit 75 and evaporates into gas. The gasified refrigerant passes through the second flow switching device 26 and is drawn into the second compressor 22 via an accumulator (not shown).

[0131] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2A is heated by the refrigerant flowing through the third intermediate heat exchanger 29 to become a high-temperature heat transfer medium, and then passes through the fourth connection part 94 and flows into the load-side heat exchanger 30 of the load device 3A connected to the relay unit 2A. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3A exchanges heat with the indoor air to be cooled, and then flows out of the load device 3A. The cooled heat transfer medium that flows out of the load device 3A passes through the fifth connection part 95 and flows again into the third intermediate heat exchanger 29 of the relay unit 2A.

[0132] In the second refrigerant circuit 20 of the relay unit 2B, high-temperature, high-pressure gas refrigerant discharged from the second compressor 22 passes through the second flow switching device 26 and flows into the third intermediate heat exchanger 29. The refrigerant that flows into the third intermediate heat exchanger 29 exchanges heat with the heat transfer medium flowing through the second heat medium circuit 76 and condenses and liquefies. The condensed and liquefied refrigerant is reduced in pressure by the relay unit flow control valve 27 to become a low-pressure gas-liquid two-phase refrigerant and flows into the second intermediate heat exchanger 28. The gas-liquid two-phase refrigerant that flows into the second intermediate heat exchanger 28 exchanges heat with the heat transfer medium flowing through the first heat medium circuit 75 and evaporates into gas. The gasified refrigerant passes through the second flow switching device 26 and is drawn into the second compressor 22 via an accumulator (not shown).

[0133] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2B is heated by the refrigerant flowing through the third intermediate heat exchanger 29 to become a high-temperature heat transfer medium, and then passes through the fourth connection part 94 and flows into the load-side heat exchanger 30 of the load device 3A connected to the relay unit 2B. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3A exchanges heat with the indoor air to be cooled, and then flows out of the load device 3A. The cooled heat transfer medium that flows out of the load device 3A passes through the fifth connection part 95 and flows again into the third intermediate heat exchanger 29 of the relay unit 2B.

[0134] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2B is heated by the refrigerant flowing through the third intermediate heat exchanger 29 to become a high-temperature heat transfer medium, then passes through the third connection part 93 and flows into the load-side heat exchanger 30 of the load device 3B connected to the relay unit 2B. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3B exchanges heat with the indoor air to be cooled, and flows out of the load device 3B. The cooled heat transfer medium that flows out of the load device 3B passes through the sixth connection part 96 and flows again into the third intermediate heat exchanger 29 of the relay unit 2B.

[0135] 5 , the heat transfer medium flowing through the first heat medium circuit 75 that flows out of the load device 3 and toward the heat source unit 1 has heat removed in the second intermediate heat exchanger 28 due to the heating operation state mode of the second refrigerant circuit 20. The heat transfer medium that has flowed out of the load side heat exchanger 30 of the load device 3 has heat removed in the second intermediate heat exchanger 28 by the refrigerant flowing through the second refrigerant circuit 20, equivalent to the amount of heat generated by the heating operation of the second refrigerant circuit 20, and the temperature of the heat transfer medium drops.

[0136] In the air conditioning apparatus 100 shown in Fig. 5, the third heat medium circuit 77 is not configured in the relay unit 2A, but is configured in the relay unit 2B. In the relay unit 2A, the heat medium bypass valve 25 is closed, and the heat transfer medium does not flow through the bypass flow path 78. In the relay unit 2B, the heat medium bypass valve 25 is open, and the heat transfer medium flows through the bypass flow path 78. In the air conditioning apparatus 100 shown in Fig. 5, the third heat medium circuit 77 is configured by the heat source unit 1 and the relay unit 2B.

[0137] The heat transfer medium flowing through the third heat medium circuit 77 is cooled by the refrigerant flowing through the first intermediate heat exchanger 9 to become a low-temperature heat transfer medium, and then flows into the second intermediate heat exchanger 28 of the relay unit 2B. The heat transfer medium that has flowed into the second intermediate heat exchanger 28 of the relay unit 2B exchanges heat with the refrigerant flowing through the second refrigerant circuit 20 to be cooled, and then flows out of the second intermediate heat exchanger 28. The heat transfer medium that has flowed out of the second intermediate heat exchanger 28 flows again into the first intermediate heat exchanger 9 of the heat source unit 1.

[0138] The heat transfer medium that has flowed out of the first intermediate heat exchanger 9 passes through the first connection part 91 and flows into the relay unit 2B, passes through the bypass flow path 78 and the heat medium bypass valve 25, and then flows into the second intermediate heat exchanger 28. The heat transfer medium that has flowed out of the second intermediate heat exchanger 28 passes through the second connection part 92 and flows out of the relay unit 2, and flows into the first intermediate heat exchanger 9 of the heat source unit 1 again.

[0139] (Heating-dominated operation mode) Fig. 6 is a circuit diagram showing an example of a heating-dominated operation mode in the air conditioning apparatus 100 according to embodiment 1. An example of a heating-dominated operation mode in the air conditioning apparatus 100 will be described with reference to Fig. 6. Fig. 6 is a circuit diagram showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when cooling and heating are performed by the load device 3. Note that dashed arrows in Fig. 6 indicate an example of the flow of the heat transfer medium. Furthermore, white shown in the heat medium flow switching device 60 indicates a state in which the valve is open, and black shown in the heat medium flow switching device 60 indicates a state in which the valve is closed.

[0140] When the air conditioning apparatus 100 according to Embodiment 1 operates in the heating-dominant operation mode, the heat source unit 1 operates in the heating operation mode, and the relay unit 2 operates in the cooling operation mode. In Fig. 6, the relay unit 2A and the relay unit 2B are in the cooling operation mode, but depending on the state of the heat load, one or more of the multiple relay units 2 may be in a stopped state.

[0141] In the heating-dominant operation mode of the air conditioning apparatus 100, the operation modes are different between the heat source unit 1 and the multiple relay units 2. In the air conditioning apparatus 100, the temperature of the heat transfer medium sent from the heat source unit 1 to the multiple relay units 2 may differ from the temperature of the heat transfer medium sent from the multiple relay units 2 to one or more of the multiple relay units 2.

[0142] In the heating-dominated operation mode of the air conditioning apparatus 100, when the heat transfer medium sent from the heat source unit 1 to the relay unit 2 is hot water, the heat transfer medium sent from the multiple relay units 2 to one or more of the multiple load devices 3 may be cold water. The heat transfer medium sent from the heat source unit 1 to the relay unit 2 here is the heat transfer medium heated by the first refrigerant circuit 10. Furthermore, the heat transfer medium sent from the relay unit 2 to one or more of the multiple load devices 3 here is the heat transfer medium cooled by the second refrigerant circuit 20.

[0143] In the heating-dominated operation mode, the air conditioning apparatus 100 according to Embodiment 1 operates the first refrigerant circuit 10, the second refrigerant circuit 20, and the first heat medium circuit 75. In addition, in the heating-dominated operation mode, the air conditioning apparatus 100 according to Embodiment 1 operates one or more of the second heat medium circuit 76 and the third heat medium circuit 77.

[0144] When the air conditioning apparatus 100 performs heating using the load device 3B connected to the relay unit 2A, the heat medium flow switching device 60 is opened and closed so as to connect the first intermediate heat exchanger 9 and the load device 3B via the relay unit 2A. In the air conditioning apparatus 100, valves such as the first heat medium flow switching device 60a, the second heat medium flow switching device 60b, the third heat medium flow switching device 60c, and the fourth heat medium flow switching device 60d of the relay unit 2A are opened and closed.

[0145] When heating is performed by the load device 3B connected to the relay unit 2A, the air conditioning device 100 opens the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d to allow the heat transfer medium to flow through the first heat medium circuit 75. When heating is performed by the load device 3B connected to the relay unit 2A, the air conditioning device 100 closes the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d to prevent the heat transfer medium from flowing through the second heat medium circuit 76.

[0146] When the air conditioning apparatus 100 performs cooling on the load device 3A connected to the relay unit 2A, the heat medium flow switching device 60 is opened and closed so as to connect the third intermediate heat exchanger 29 of the relay unit 2A to the load device 3A. The air conditioning apparatus 100 opens and closes valves such as the first heat medium flow switching device 60a, the second heat medium flow switching device 60b, the third heat medium flow switching device 60c, and the fourth heat medium flow switching device 60d of the relay unit 2A.

[0147] When the air conditioning apparatus 100 performs cooling on the load device 3A connected to the relay unit 2A, it closes the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c so that the heat transfer medium does not flow through the first heat medium circuit 75. When the air conditioning apparatus 100 performs cooling on the load device 3A connected to the relay unit 2A, it opens the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c so that the heat transfer medium flows through the second heat medium circuit 76.

[0148] When the air conditioning apparatus 100 performs cooling using the load devices 3A and 3B of the relay unit 2B, the heat medium flow switching device 60 is opened and closed so as to connect the third intermediate heat exchanger 29 of the relay unit 2B to the load devices 3A and 3B. The air conditioning apparatus 100 opens and closes valves such as the first heat medium flow switching device 60a and the second heat medium flow switching device 60b, and the third heat medium flow switching device 60c and the fourth heat medium flow switching device 60d of the relay unit 2B.

[0149] When the air conditioning apparatus 100 performs cooling on the load device 3A connected to the relay unit 2B, it closes the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c so that the heat transfer medium does not flow through the first heat medium circuit 75. When the air conditioning apparatus 100 performs cooling on the load device 3A connected to the relay unit 2B, it opens the valves of the second heat medium flow switching device 60b and the third heat medium flow switching device 60c so that the heat transfer medium flows through the second heat medium circuit 76.

[0150] When the air conditioning apparatus 100 performs cooling on the load device 3B connected to the relay unit 2B, it closes the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d so that the heat transfer medium does not flow through the first heat medium circuit 75. When the air conditioning apparatus 100 performs cooling on the load device 3B connected to the relay unit 2B, it opens the valves of the first heat medium flow switching device 60a and the fourth heat medium flow switching device 60d so that the heat transfer medium flows through the second heat medium circuit 76.

[0151] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching device 6 and flows into the first intermediate heat exchanger 9. The refrigerant that flows into the first intermediate heat exchanger 9 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75, the third heat medium circuit 77, etc., and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the heat source-side flow control valve 7 to become a low-pressure gas-liquid two-phase refrigerant, and flows into the air heat exchanger 13. The gas-liquid two-phase refrigerant that flows into the air heat exchanger 13 exchanges heat with air and is evaporated and gasified. The gasified refrigerant passes through the first flow switching device 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0152] The heat transfer medium flowing through the first heat medium circuit 75 is heated by the refrigerant flowing through the first intermediate heat exchanger 9 to become a high-temperature heat transfer medium, and then flows into the load-side heat exchanger 30 of the load device 3B via the relay unit 2A. The heat transfer medium that flowed into the load-side heat exchanger 30 of the load device 3B exchanges heat with the indoor air to be cooled, and flows out of the load device 3B. The cooled heat transfer medium that flowed out of the load device 3B flows again into the first intermediate heat exchanger 9 of the heat source device 1 via the relay unit 2A.

[0153] The heat transfer medium that has flowed out of the first intermediate heat exchanger 9 passes through the first connection part 91 to flow into the relay unit 2A, and then passes through the first heat medium flow switching device 60a and the third connection part 93 to flow out of the relay unit 2A. The heat transfer medium that has flowed out of the relay unit 2A through the first heat medium flow switching device 60a and the third connection part 93 passes through the load-side heat exchanger 30 of the load device 3B and then flows out of the load device 3B. The heat transfer medium that has flowed out of the load device 3B passes through the sixth connection part 96 to flow into the relay unit 2A, passes through the fourth heat medium flow switching device 60d and the second intermediate heat exchanger 28, and then passes through the second connection part 92 to flow out of the relay unit 2A.

[0154] In the second refrigerant circuit 20 of the relay unit 2A, high-temperature, high-pressure gas refrigerant discharged from the second compressor 22 passes through the second flow switching device 26 and flows into the second intermediate heat exchanger 28. The refrigerant that flows into the second intermediate heat exchanger 28 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75 and the like, and is condensed and liquefied. The condensed and liquefied refrigerant is decompressed by the relay unit flow control valve 27 to become a low-pressure gas-liquid two-phase refrigerant, and flows into the third intermediate heat exchanger 29. The gas-liquid two-phase refrigerant that flows into the third intermediate heat exchanger 29 exchanges heat with the heat transfer medium flowing through the second heat medium circuit 76, and is evaporated and gasified. The gasified refrigerant passes through the second flow switching device 26 and is drawn into the second compressor 22 via an accumulator (not shown).

[0155] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2A is cooled by the refrigerant flowing through the third intermediate heat exchanger 29 to become a low-temperature heat transfer medium, then passes through the fourth connection part 94 and flows into the load-side heat exchanger 30 of the load device 3A connected to the relay unit 2A. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3A exchanges heat with the indoor air to be heated, and flows out of the load device 3A. The heated heat transfer medium that flows out of the load device 3A passes through the fifth connection part 95 and flows again into the third intermediate heat exchanger 29 of the relay unit 2A.

[0156] In the second refrigerant circuit 20 of the relay unit 2B, high-temperature, high-pressure gas refrigerant discharged from the second compressor 22 passes through the second flow switching device 26 and flows into the second intermediate heat exchanger 28. The refrigerant that flows into the second intermediate heat exchanger 28 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the third heat medium circuit 77 and the like, and is condensed and liquefied. The condensed and liquefied refrigerant is decompressed by the relay unit flow control valve 27 to become a low-pressure gas-liquid two-phase refrigerant, and flows into the third intermediate heat exchanger 29. The gas-liquid two-phase refrigerant that flows into the third intermediate heat exchanger 29 exchanges heat with the heat transfer medium flowing through the second heat medium circuit 76 and is evaporated and gasified. The gasified refrigerant passes through the second flow switching device 26 and is drawn into the second compressor 22 via an accumulator (not shown).

[0157] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2B is cooled by the refrigerant flowing through the third intermediate heat exchanger 29 to become a low-temperature heat transfer medium, and then passes through the fourth connection part 94 and flows into the load-side heat exchanger 30 of the load device 3A connected to the relay unit 2B. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3A exchanges heat with the indoor air to be heated, and then flows out of the load device 3A. The heated heat transfer medium that flows out of the load device 3A passes through the fifth connection part 95 and flows again into the third intermediate heat exchanger 29 of the relay unit 2B.

[0158] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2B is cooled by the refrigerant flowing through the third intermediate heat exchanger 29 to become a low-temperature heat transfer medium, then passes through the third connection part 93 and flows into the load-side heat exchanger 30 of the load device 3B connected to the relay unit 2B. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3B exchanges heat with the indoor air to be heated, and flows out of the load device 3B. The heated heat transfer medium that flows out of the load device 3B passes through the sixth connection part 96 and flows again into the third intermediate heat exchanger 29 of the relay unit 2B.

[0159] 6 , the heat transfer medium flowing through the first heat medium circuit 75 that flows out of the load device 3 and toward the heat source unit 1 is given heat in the second intermediate heat exchanger 28 in accordance with the cooling operation state mode of the second refrigerant circuit 20. The heat transfer medium that has flowed out of the load side heat exchanger 30 of the load device 3 is given heat in the second intermediate heat exchanger 28 by the refrigerant flowing through the second refrigerant circuit 20 in an amount equivalent to the amount of heat produced by the cooling operation of the second refrigerant circuit 20, and the temperature of the heat transfer medium rises.

[0160] In the air conditioning apparatus 100 shown in Fig. 6, the third heat medium circuit 77 is not configured in the relay unit 2A, but is configured in the relay unit 2B. In the relay unit 2A, the heat medium bypass valve 25 is closed, and the heat transfer medium does not flow through the bypass flow path 78. In the relay unit 2B, the heat medium bypass valve 25 is open, and the heat transfer medium flows through the bypass flow path 78. In the air conditioning apparatus 100 shown in Fig. 6, the third heat medium circuit 77 is configured by the heat source unit 1 and the relay unit 2B.

[0161] The heat transfer medium flowing through the third heat medium circuit 77 is heated by the refrigerant flowing through the first intermediate heat exchanger 9 to become a high-temperature heat transfer medium, and then flows into the second intermediate heat exchanger 28 of the relay unit 2B. The heat transfer medium that has flowed into the second intermediate heat exchanger 28 of the relay unit 2B is heated by heat exchange with the refrigerant flowing through the second refrigerant circuit 20, and flows out of the second intermediate heat exchanger 28. The heat transfer medium that has flowed out of the second intermediate heat exchanger 28 flows again into the first intermediate heat exchanger 9 of the heat source unit 1.

[0162] The heat transfer medium that has flowed out of the first intermediate heat exchanger 9 passes through the first connection part 91 and flows into the relay unit 2B, passes through the bypass flow path 78 and the heat medium bypass valve 25, and then flows into the second intermediate heat exchanger 28. The heat transfer medium that has flowed out of the second intermediate heat exchanger 28 passes through the second connection part 92 and flows out of the relay unit 2, and flows into the first intermediate heat exchanger 9 of the heat source unit 1 again.

[0163] In the air conditioning apparatus 100, all of the load devices 3 may be indoor units, or may be hot water storage tanks for supplying hot water to some or all of the multiple load devices 3. In the air conditioning apparatus 100, when the load devices 3 are hot water storage tanks, the heat transfer medium flowing through the heat transfer medium circuit 71 is water supplied to the hot water storage tanks that are the load devices 3. The hot water storage tanks store water supplied via a water supply pipe (not shown). The hot water storage tanks store hot water heated by the heat source unit 1, the relay unit 2, or the relay unit 2. When the load devices 3 are hot water storage tanks, hot water storage is performed in an operating mode similar to the heating operation mode in the load devices 3 described above, as an example.

[0164] The number of load devices 3 connected to each relay unit 2 may be one, or three or more. In this case, the air conditioning apparatus 100 may have all of the load devices 3 as indoor units, or may have some or all of the load devices 3 as hot water storage tanks for supplying hot water. Furthermore, some of the load devices 3 may be connected directly to the heat source unit 1 without going through the relay unit 2.

[0165] [Operation and Effect of Air Conditioning Apparatus 100] The air conditioning apparatus 100 comprises at least one heat source unit 1, a plurality of relay units 2 connected to the at least one heat source unit 1, and a plurality of load devices 3 connected to the plurality of relay units 2. The air conditioning apparatus 100 also comprises a plurality of connection pipes 70 that connect the at least one heat source unit 1, the plurality of relay units 2, and the plurality of load devices 3. The at least one heat source unit 1 comprises a first refrigerant circuit 10 through which a refrigerant circulates. The first refrigerant circuit 10 has a first intermediate heat exchanger 9 that exchanges heat between the refrigerant flowing through the first refrigerant circuit 10 and a heat transfer medium flowing therein, and an air heat exchanger 13 that exchanges heat between the refrigerant flowing through the first refrigerant circuit 10 and air.

[0166] The multiple relay units 2 include second refrigerant circuits 20 through which refrigerant circulates. The second refrigerant circuit 20 has a second intermediate heat exchanger 28 in which the refrigerant flowing through the second refrigerant circuit 20 exchanges heat with a heat transfer medium flowing therethrough, and a third intermediate heat exchanger 29 in which the refrigerant flowing through the second refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therethrough. The air conditioning apparatus 100 is configured so that the heat transfer medium flows between at least one heat source unit 1, the multiple relay units 2, and at least one of the multiple load devices 3 via multiple connection pipes 70. In the air conditioning apparatus 100, the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 is adjusted between the multiple relay units 2.

[0167] Therefore, when cooling and heating are performed simultaneously by multiple load devices 3, the air conditioning apparatus 100 according to Embodiment 1 can perform cooling or heating using the first refrigerant circuit 10 provided in the heat source unit 1 and the second refrigerant circuit 20 provided in the relay unit 2. The air conditioning apparatus 100 can reduce the number of pipes connecting the heat source unit 1 and the relay unit 2 to two, which reduces the number of pipes required and reduces the burden of piping work.

[0168] The air conditioning apparatus 100 is configured so that a heat transfer medium flows between at least one heat source unit 1, multiple relay units 2, and at least one of multiple load devices 3 via multiple connection pipes 70. In the air conditioning apparatus 100, the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 is adjusted between the multiple relay units 2. Therefore, when multiple load devices 3 simultaneously perform cooling and heating, the air conditioning apparatus 100 according to embodiment 1 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall. The air conditioning apparatus 100 according to embodiment 1 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall and improving comfort in the indoor space.

[0169] Each of the multiple relay units 2 has a flow rate adjustment mechanism 80 that adjusts the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 between the multiple relay units 2. Therefore, when multiple load devices 3 simultaneously perform cooling and heating, the air conditioning apparatus 100 according to embodiment 1 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby enabling efficient operation overall. The air conditioning apparatus 100 according to embodiment 1 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby enabling efficient operation overall and improving comfort in the indoor space.

[0170] Furthermore, the flow rate adjustment mechanism 80 includes a first heat medium flow switching device 60a, a second heat medium flow switching device 60b, a third heat medium flow switching device 60c, a fourth heat medium flow switching device 60d, and a bypass flow path 78 having a heat medium bypass valve 25. By virtue of this configuration, when multiple load devices 3 simultaneously perform cooling and heating, the air conditioning apparatus 100 according to the first embodiment can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall. The air conditioning apparatus 100 according to the first embodiment can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall and improving the comfort of the indoor space.

[0171] Furthermore, the flow rate adjustment mechanism 80 adjusts the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 in accordance with the thermal loads of the multiple load devices 3. By having this configuration, when multiple load devices 3 simultaneously perform cooling and heating, the air conditioning apparatus 100 according to embodiment 1 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall. Because the air conditioning apparatus 100 according to embodiment 1 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, it can achieve efficient operation overall and improve comfort in the indoor space.

[0172] The air conditioning apparatus 100 has a first heat medium flow switching device 60a, a second heat medium flow switching device 60b, a third heat medium flow switching device 60c, a fourth heat medium flow switching device 60d, and a heat medium bypass valve 25. This configuration allows the air conditioning apparatus 100 to switch the flow path of the heat transfer medium to form a first heat medium circuit 75, a second heat medium circuit 76, and a third heat medium circuit 77. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the relay unit 2 and the load devices 3 are different from those of the heat source unit 1. Furthermore, the air conditioning apparatus 100 can supply the heat transfer medium more efficiently to the thermal loads required by the multiple load devices 3 and the multiple relay units 2 compared to an air conditioning apparatus not having this configuration. Furthermore, by having this configuration, the air conditioning device 100 can reduce the number of pipes connecting the heat source unit 1 and the relay unit 2 to two, which reduces the number of pipes required and reduces the burden of piping work.

[0173] Furthermore, in the multiple relay units 2, the first connection 91 and the heat source unit 1 are connected in the first flow path 211 so that the heat transfer medium flows from the first connection 91 side toward the third connection 93 and the fourth connection 94 side. Furthermore, in the multiple relay units 2, the second connection 92 and the heat source unit 1 are connected in the second flow path 212 so that the heat transfer medium flows from the fifth connection 95 and the sixth connection 96 side toward the second connection 92 side. By having this configuration, the air conditioning apparatus 100 according to embodiment 1 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2 when multiple load devices 3 simultaneously perform cooling and heating, thereby enabling efficient operation overall.

[0174] Furthermore, in the air conditioning apparatus 100, the heat source unit 1 and the relay unit 2 are connected by two connection pipes 70, and the relay unit 2 and the load device 3 are each connected by two connection pipes 70. In the air conditioning apparatus 100, there are two pipes connecting the heat source unit 1 and the relay unit 2, and there are also two pipes connecting the relay unit 2 and the load device 3. Therefore, compared to air conditioning apparatuses that require two pipes each for cooling and heating, the air conditioning apparatus 100 requires fewer pipes, reducing the burden of piping work.

[0175] Furthermore, in the air conditioning apparatus 100, in one or more of the relay units 2, heat exchange occurs between the heat transfer medium flowing through the second intermediate heat exchanger 28 and the refrigerant in the second refrigerant circuit 20, and heat exchange occurs between the heat transfer medium flowing through the third intermediate heat exchanger 29 and the refrigerant in the second refrigerant circuit 20. In the air conditioning apparatus 100, in the relay unit 2, the heat transfer medium flowing through the second intermediate heat exchanger 28 generates a heat transfer medium in the third intermediate heat exchanger 29, via the refrigerant flowing through the second refrigerant circuit 20, having a temperature range different from that of the heat transfer medium flowing through the second intermediate heat exchanger 28. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the relay units 2 and the load devices 3 are different from those of the heat source unit 1. Furthermore, the air conditioning apparatus 100 can supply the heat transfer medium more efficiently to the thermal loads required by the multiple load devices 3 and the multiple relay units 2, compared to an air conditioning apparatus not having this configuration.

[0176] Furthermore, the second refrigerant circuits 20 of the multiple relay units 2 remove heat from a first heat transfer medium flowing through one of two connection pipes 70 connecting the heat source units 1 and the relay units 2, and provide heat to a second heat transfer medium flowing through at least one of the multiple load devices 3. Alternatively, the second refrigerant circuit 20 of the relay unit 2 provides heat to the first heat transfer medium flowing through one of two connection pipes 70 connecting the heat source units 1 and the relay units 2, and removes heat from the second heat transfer medium flowing through at least one of the multiple load devices 3. The second refrigerant circuit 20 of the relay unit 2 changes the temperatures of the first heat transfer medium and the second heat transfer medium through this configuration. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the relay units 2 and the load devices 3 are different from those of the heat source unit 1. Furthermore, compared to an air conditioning device 100 that does not have this configuration, the air conditioning device 100 can efficiently supply heat transfer medium to the heat load required by multiple load devices 3 and multiple relay units 2.

[0177] The air conditioning apparatus 100 also includes a control device 40 that controls at least one heat source unit 1, multiple relay units 2, and multiple load devices 3. The control device 40 controls all operation modes of the at least one heat source unit 1 so that they are in an operation mode with a larger thermal load than the overall thermal load of the system. The control device 40 also controls and operates at least one operation mode of the multiple relay units 2 so that they are in an operation mode with a smaller thermal load than the overall thermal load of the system. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the relay units 2 and the load devices 3 are different from those of the heat source unit 1. Furthermore, the air conditioning apparatus 100 can supply a heat transfer medium more efficiently to the thermal loads required by the multiple load devices 3 and multiple relay units 2 compared to an air conditioning apparatus without a relay unit 2.

[0178] Embodiment 2. Fig. 7 is a schematic diagram showing an air conditioning apparatus 100 according to embodiment 2. Fig. 8 is a circuit diagram showing an example of a cooling-dominated operation mode in the air conditioning apparatus 100 according to embodiment 2. Fig. 9 is a circuit diagram showing another example of a cooling-dominated operation mode in the air conditioning apparatus 100 according to embodiment 2. Next, the air conditioning apparatus 100 according to embodiment 2 will be described with reference to Figs. 7 to 9. Note that the same components as those in the air conditioning apparatus 100 described in embodiment 1 will be assigned the same reference numerals, and their description will be omitted as appropriate.

[0179] The air conditioning apparatus 100 according to the second embodiment differs from the air conditioning apparatus 100 according to the first embodiment in that it has a flow rate adjustment valve 81. In the air conditioning apparatus 100 according to the second embodiment, the flow rate adjustment valve 81 that adjusts the flow rate of the heat transfer medium is provided in the first flow path 211 of the multiple relay units 2, in a portion between the first connection part 91 and the bypass flow path 78.

[0180] The flow rate adjustment valve 81 adjusts the flow rate of the heat transfer medium flowing in and out of the relay unit 2 by controlling its opening and closing. The flow rate adjustment valve 81 is configured as, for example, a two-way valve, and its opening and closing is controlled by the control device 40. The flow rate adjustment valve 81 may be configured as, for example, a two-way valve whose valve opening degree (opening area) can be controlled. The flow rate adjustment valve 81 controls the flow of the heat transfer medium flowing in and out of the load-side heat exchanger 30 of the load device 3 by controlling its opening and closing.

[0181] Each of the plurality of relay units 2 has a flow rate adjustment mechanism 80 that adjusts the flow rate of the heat transfer medium flowing through each of the plurality of relay units 2 between the plurality of relay units 2. The flow rate adjustment mechanism 80 includes a first heat medium flow path switching device 60a, a second heat medium flow path switching device 60b, a third heat medium flow path switching device 60c, a fourth heat medium flow path switching device 60d, a bypass flow path 78 having a heat medium bypass valve 25, and a flow rate adjustment valve 81. The flow rate adjustment mechanism 80 adjusts the flow rate of the heat transfer medium flowing through each of the plurality of relay units 2 in accordance with the thermal loads of the plurality of load devices 3, for example.

[0182] 8 and 9, the heat medium flow switching device 60 may include a fifth heat medium flow switching device 60e and a sixth heat medium flow switching device 60f. When there are three load devices 3, the load devices 3 can be connected to these heat medium flow switching devices 60.

[0183] In the relay unit 2 and load device 3 of the air conditioning apparatus 100 shown in Figure 8, the heat transfer medium flows in the same manner as the heat transfer medium in the relay unit 2 and load device 3 of the air conditioning apparatus 100 of embodiment 1 shown in Figure 5.

[0184] In the repeater unit 2A of the air conditioning apparatus 100 and the load device 3 shown in Figure 9, the heat transfer medium flows in the same manner as the heat transfer medium in the repeater unit 2A of the air conditioning apparatus 100 and the load device 3 of the first embodiment shown in Figure 5. Furthermore, in the repeater unit 2B of the air conditioning apparatus 100 and the load device 3 shown in Figure 9, the heat transfer medium flows in the same manner as the heat transfer medium in the repeater unit 2A of the air conditioning apparatus 100 and the load device 3 of the first embodiment shown in Figure 5. Note that the flow of the heat transfer medium shown in Figures 8 and 9 is an example and is not limited to this configuration.

[0185] [Operation and effect of the air conditioning apparatus 100] In the air conditioning apparatus 100, a flow rate adjustment valve 81 that adjusts the flow rate of the heat transfer medium is provided in a portion of the first flow path 211 of the multiple relay units 2 between the first connection portion 91 and the bypass flow path 78. The flow rate adjustment mechanism 80 includes a first heat medium flow path switching device 60a, a second heat medium flow path switching device 60b, a third heat medium flow path switching device 60c, a fourth heat medium flow path switching device 60d, a bypass flow path 78 having a heat medium bypass valve 25, and the flow rate adjustment valve 81.

[0186] By having this configuration, the air conditioning apparatus 100 according to the second embodiment can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2 when multiple load devices 3 simultaneously perform cooling and heating, thereby achieving efficient operation overall. In the air conditioning apparatus 100, the relay units 2 have flow control valves 81, making it easier to adjust the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 between the multiple relay units 2 compared to when the air conditioning apparatus 100 does not have flow control valves 81. Therefore, the air conditioning apparatus 100 according to the second embodiment can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall and improving comfort in the indoor space.

[0187] Embodiment 3. Figure 10 is a schematic diagram showing an air conditioning apparatus 100 according to embodiment 3. Figure 11 is a circuit diagram showing an example of a cooling-dominated operation mode in the air conditioning apparatus 100 according to embodiment 3. Figure 12 is a circuit diagram showing another example of a cooling-dominated operation mode in the air conditioning apparatus 100 according to embodiment 3. Next, the air conditioning apparatus 100 according to embodiment 3 will be described with reference to Figures 10 to 12. Note that the same components as those in the air conditioning apparatus 100 described in embodiments 1 and 2 will be assigned the same reference numerals, and their description will be omitted as appropriate.

[0188] The air conditioning apparatus 100 according to Embodiment 3 differs from the air conditioning apparatus 100 according to Embodiments 1 and 2 in that it has a circulation pump 82. The air conditioning apparatus 100 according to Embodiment 2 is provided with a circulation pump 82 that adjusts the flow rate of the heat transfer medium in the first flow paths 211 of the multiple relay units 2.

[0189] The circulation pump 82 circulates the heat transfer medium so that it flows between the heat source unit 1, the relay unit 2, and at least one of the plurality of load devices 3 via the plurality of connection pipes 70. In the air conditioning apparatus 100 of Figures 10 to 12, the heat source unit 1 is provided with a first pump 11, but the heat source unit 1 may not be provided with a first pump 11, and the circulation pump 82 of the relay unit 2 may replace the first pump 11.

[0190] The circulation pump 82 circulates the heat transfer medium by sucking it in through the first flow path 211 and applying pressure to send it out. The capacity of the circulation pump 82 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the circulation pump 82 by arbitrarily changing the drive frequency based on instructions from the control device 40. The circulation pump 82 adjusts the flow rate of the heat transfer medium flowing in and out of the relay unit 2.

[0191] Each of the plurality of relay units 2 has a flow rate adjustment mechanism 80 that adjusts the flow rate of the heat transfer medium flowing through each of the plurality of relay units 2 between the plurality of relay units 2. The flow rate adjustment mechanism 80 includes a first heat medium flow path switching device 60a, a second heat medium flow path switching device 60b, a third heat medium flow path switching device 60c, a fourth heat medium flow path switching device 60d, a bypass flow path 78 having a heat medium bypass valve 25, and a circulation pump 82. The flow rate adjustment mechanism 80 adjusts the flow rate of the heat transfer medium flowing through each of the plurality of relay units 2 in accordance with the thermal loads of the plurality of load devices 3, for example.

[0192] In the relay unit 2 and load device 3 of the air conditioning apparatus 100 shown in Figure 11, the heat transfer medium flows in the same manner as the heat transfer medium in the relay unit 2 and load device 3 of the air conditioning apparatus 100 of embodiment 1 shown in Figure 5.

[0193] In the repeater unit 2A of the air conditioning apparatus 100 and the load device 3 shown in Figure 12, the heat transfer medium flows in the same manner as the heat transfer medium in the repeater unit 2A of the air conditioning apparatus 100 and the load device 3 of the first embodiment shown in Figure 5. Furthermore, in the repeater unit 2B of the air conditioning apparatus 100 and the load device 3 shown in Figure 12, the heat transfer medium flows in the same manner as the heat transfer medium in the repeater unit 2A of the air conditioning apparatus 100 and the load device 3 of the first embodiment shown in Figure 5. Note that the flow of the heat transfer medium shown in Figures 11 and 12 is an example and is not limited to this configuration.

[0194] 13 is a flow diagram showing an example of control by the control device 40 in the air conditioning apparatus 100 according to Embodiment 3. When cooling-dominated operation or heating-dominated operation is started, the control device 40 compares the outlet water temperature of the second intermediate heat exchanger 28 with a threshold value, and determines whether the outlet water temperature is equal to or lower than the threshold value, i.e., whether the outlet water temperature is equal to or lower than the threshold value (step S1). The outlet water temperature is the temperature of the heat transfer medium and is detected, for example, by the second heat medium temperature sensor 44. The threshold value is, for example, 5°C, but the threshold value is determined based on various conditions.

[0195] If the outlet water temperature is greater than the threshold (NO in step S1), the control device 40 repeats step S1 to determine whether the outlet water temperature is equal to or less than the threshold. If the outlet water temperature is equal to or less than the threshold (YES in step S1), the control device 40 increases the flow rate of the heat transfer medium flowing into the relay unit 2 (step S2).

[0196] When increasing the flow rate of the heat transfer medium flowing into the relay unit 2, the control device 40 determines whether the relay unit 2 has a flow rate adjustment valve 81 (step S3). When increasing the flow rate of the heat transfer medium flowing into the relay unit 2 and the relay unit 2 has a flow rate adjustment valve 81 (if step S3 is YES), the control device 40 increases the opening degree of the flow rate adjustment valve 81 (step S4). When increasing the flow rate of the heat transfer medium flowing into the relay unit 2 and the relay unit 2 does not have a flow rate adjustment valve 81 (if step S3 is NO), the control device 40 determines whether the relay unit 2 has a circulation pump 82 (step S5).

[0197] When the flow rate of the heat transfer medium flowing into the relay unit 2 is increased and the relay unit 2 has a circulation pump 82 (if step S5 is YES), the control device 40 increases the rotation speed of the circulation pump 82 (step S6). When the flow rate of the heat transfer medium flowing into the relay unit 2 is increased and the relay unit 2 does not have a circulation pump 82 (if step S5 is NO), the control device 40 reduces the rotation speed of the second compressor 22 (step S7).

[0198] The control device 40 can operate the air conditioning device 100 in accordance with the thermal load by increasing the opening of the flow rate adjustment valve 81 (step S4), increasing the rotation speed of the circulation pump 82 (step S6), or reducing the rotation speed of the second compressor 22 (step S7). Furthermore, by performing this control, the control device 40 can operate the air conditioning device 100 in accordance with the thermal load of the load device 3, thereby improving comfort. Furthermore, by performing this control, the control device 40 can prevent the temperature of the heat transfer medium from dropping too low, preventing the air conditioning device 100 from freezing.

[0199] [Operation and effect of the air conditioning apparatus 100] In the air conditioning apparatus 100, a circulation pump 82 is provided in the first flow paths 211 of the multiple relay units 2, which circulates the heat transfer medium so that the heat transfer medium flows between the heat source unit 1, the relay unit 2, and at least one of the multiple load devices 3 via the multiple connection pipes 70. The flow rate adjustment mechanism 80 includes a first heat medium flow switching device 60a, a second heat medium flow switching device 60b, a third heat medium flow switching device 60c, a fourth heat medium flow switching device 60d, a bypass flow path 78 having a heat medium bypass valve 25, and the circulation pump 82.

[0200] By having this configuration, the air conditioning apparatus 100 according to embodiment 3 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2 when multiple load devices 3 simultaneously perform cooling and heating, thereby achieving efficient operation overall. In the air conditioning apparatus 100, the relay units 2 have a circulation pump 82, making it easier to adjust the flow rate of the heat transfer medium flowing through each of the multiple relay units 2 between the multiple relay units 2 compared to an air conditioning apparatus 100 not having a circulation pump 82. Therefore, the air conditioning apparatus 100 according to embodiment 3 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall and improving comfort in the indoor space.

[0201] Embodiment 4. Figure 14 is a configuration diagram that schematically shows an air conditioning apparatus 100 according to embodiment 4. Figure 15 is a circuit diagram that schematically shows an air conditioning apparatus 100 according to embodiment 4. Figure 16 is a circuit diagram that schematically shows a first modified example of the air conditioning apparatus 100 according to embodiment 4. Next, the air conditioning apparatus 100 according to embodiment 4 will be described with reference to Figures 14 to 16. Note that the same components as those in the air conditioning apparatus 100 described in embodiments 1 to 3 will be assigned the same reference numerals, and their description will be omitted as appropriate.

[0202] The air conditioning apparatus 100 pertaining to Embodiment 4 differs from the air conditioning apparatus 100 pertaining to Embodiments 1 to 3 in that it has an intermediate repeater 300. The air conditioning apparatus 100 pertaining to Embodiment 4 shown in Figure 16 differs from the air conditioning apparatus 100 pertaining to Embodiment 4 shown in Figure 15 in that a circulation pump 82 is provided in the repeater 2.

[0203] The air conditioning apparatus 100 further includes intermediate relays 300 between at least one heat source unit 1 and multiple relay units 2, each of which includes a flow rate adjustment mechanism 80A that adjusts the flow rate of the heat transfer medium flowing through each of the multiple relay units 2. The intermediate relays 300 are installed, for example, inside a building 200. Note that although the air conditioning apparatus 100 in Figures 15 and 16 includes one intermediate relay unit 300, the air conditioning apparatus 100 may also include multiple intermediate relays 300.

[0204] The intermediate relay unit 300 performs a similar function to the flow control valve 81 ( FIG. 7 ) and unifies multiple flow control valves 81. The intermediate relay unit 300 has an intermediate main body 320 that houses equipment therein. The intermediate relay unit 300 has a first intermediate connection portion 391 and a second intermediate connection portion 392 that are connected to multiple connection pipes 70 on the heat source unit 1 side, and multiple third intermediate connection portions 393 and multiple fourth intermediate connection portions 394 that are connected to multiple connection pipes 70 on the relay unit 2 side. The first intermediate connection portion 391, the second intermediate connection portion 392, the multiple third intermediate connection portions 393, and the multiple fourth intermediate connection portions 394 are provided on the intermediate main body 320.

[0205] The first intermediate connection portion 391 is a portion of the intermediate main body portion 320 through which the heat transfer medium flows in from the heat source unit 1 side. The second intermediate connection portion 392 is a portion of the intermediate main body portion 320 through which the heat transfer medium flows out toward the heat source unit 1 side. The third intermediate connection portion 393 is a portion of the intermediate main body portion 320 through which the heat transfer medium flows out toward the relay unit 2 side. The fourth intermediate connection portion 394 is a portion of the intermediate main body portion 320 through which the heat transfer medium flows in from the relay unit 2 side.

[0206] The intermediate repeater 300 has an intermediate first flow path 351 that branches so that one end is an intermediate first connection portion 391 and the other end is a plurality of intermediate third connection portions 393. The intermediate repeater 300 also has an intermediate second flow path 352 that branches so that one end is an intermediate second connection portion 392 and the other end is a plurality of intermediate fourth connection portions 394. The intermediate repeater 300 also has an intermediate third flow path 353 that branches so that one end is an intermediate second connection portion 392 and the other end is a plurality of intermediate fourth connection portions 394. The intermediate second flow path 352 and the intermediate third flow path 353 are partially common flow paths.

[0207] The intermediate relay unit 300 has one end connected to the intermediate third flow path 353 and the other end branching into a plurality of intermediate third connection portions 393. One end of the intermediate fourth flow path 354 is connected to the intermediate third flow path 353 between a first flow path switching valve 331 (described later) and a second intermediate heat medium flow path switching device 312. The other end of the intermediate fourth flow path 354 is connected to the first intermediate heat medium flow path switching device 311 (described later). The intermediate fourth flow path 354 is provided with a second flow path switching valve 332 (described later).

[0208] The intermediate relay 300 has a plurality of flow path switching valves 330 serving as on-off valves. The plurality of flow path switching valves 330 include, for example, a first flow path switching valve 331 and a second flow path switching valve 332.

[0209] The first flow path switching valve 331 is provided in the third intermediate flow path 353, in a portion between a branching portion of the third intermediate flow path 353 and the second intermediate flow path 352 and a branching portion of the third intermediate flow path 353 and the fourth intermediate flow path 354. The second flow path switching valve 332 is provided in the fourth intermediate flow path 354, in a portion between a branching portion of the third intermediate flow path 353 and the fourth intermediate flow path 354 and a branching portion of the flow path connected to the first intermediate heat medium flow path switching device 311.

[0210] The first flow path switching valve 331 and the second flow path switching valve 332 are configured as, for example, two-way valves, and their opening and closing is controlled by the control device 40. The first flow path switching valve 331 and the second flow path switching valve 332 may be configured as two-way valves whose valve opening degree (opening area) can be controlled. The first flow path switching valve 331 and the second flow path switching valve 332 control the flow of the heat transfer medium flowing in and out of the intermediate relay unit 300 by controlling their opening and closing.

[0211] The first intermediate flow path 351, the second intermediate flow path 352, the third intermediate flow path 353, and the fourth intermediate flow path 354 form flow paths through which the heat transfer medium flows inside the intermediate relay device 300. The first intermediate flow path 351, the second intermediate flow path 352, the third intermediate flow path 353, and the fourth intermediate flow path 354 form part of the heat transfer medium circuit 71 inside the intermediate relay device 300.

[0212] The intermediate relay 300 has a plurality of intermediate heat medium flow switching devices 310 that switch the flow path of the heat transfer medium, and a plurality of flow switching valves 330 that serve as on-off valves. The flow rate adjustment mechanism 80A of the intermediate relay 300 includes the plurality of intermediate heat medium flow switching devices 310 and the plurality of flow switching valves 330.

[0213] The intermediate relay 300 has a flow rate adjustment mechanism 80A that adjusts the flow rate of the heat transfer medium flowing through each of the multiple relays 2 between the multiple relays 2. The flow rate adjustment mechanism 80A adjusts the flow rate of the heat transfer medium flowing into the relay 2. The flow rate adjustment mechanism 80A adjusts the flow rate of the heat transfer medium flowing through each of the multiple relays 2 in accordance with, for example, the thermal loads of the multiple load devices 3. The flow rate adjustment mechanism 80A is controlled by, for example, the control device 40. Note that the flow rate adjustment mechanism 80A may also be controlled by a person.

[0214] The intermediate relay 300 has a plurality of intermediate heat medium flow switching devices 310. The plurality of intermediate heat medium flow switching devices 310 are respectively provided at an outflow side portion of the intermediate relay 300 from which the heat transfer medium flows toward the plurality of relays 2, and at an inflow side portion of the heat transfer medium flows from the plurality of relays 2 to the intermediate relay 300. The intermediate heat medium flow switching device 310 is formed, for example, by a three-way valve, and its opening and closing is controlled by the control device 40 or by a person. Furthermore, the flow path of the intermediate heat medium flow switching device 310 can be switched by the control device 40 or by a person.

[0215] The intermediate heat medium flow switching device 310 may be configured with a two-way valve or the like. Furthermore, the intermediate heat medium flow switching device 310 may be configured with, for example, a valve whose opening degree (opening area) can be controlled. In the air conditioning apparatus 100, the flow path of the heat transfer medium flowing in and out of the intermediate relay unit 300 is controlled by controlling the opening and closing of the intermediate heat medium flow switching device 310 provided in the intermediate relay unit 300.

[0216] In the intermediate relay 300, the plurality of intermediate heat medium flow switching devices 310 are configured by six valves: three first intermediate heat medium flow switching devices 311 and three second intermediate heat medium flow switching devices 312. The number of the plurality of intermediate heat medium flow switching devices 310 is not limited to six, and may be less than six or more than six depending on the number of relays 2 connected to the intermediate relay 300, for example.

[0217] The three first intermediate heat medium flow switching devices 311 are provided at the confluence of the first intermediate flow path 351 and the fourth intermediate flow path 354, and switch the flow path of the heat transfer medium. The three first intermediate heat medium flow switching devices 311 are provided in the intermediate relay 300 on the outflow side of the heat transfer medium flowing from the intermediate relay 300 to the multiple relays 2.

[0218] The three second intermediate heat medium flow switching devices 312 are provided at the confluence of the second intermediate flow path 352 and the third intermediate flow path 353, and switch the flow path of the heat transfer medium. The three second intermediate heat medium flow switching devices 312 are provided at the inflow side of the heat transfer medium flowing from the multiple relays 2 to the intermediate relay 300.

[0219] Fig. 17 is a circuit diagram showing an example of a cooling operation mode in the air conditioning apparatus 100 according to embodiment 4. Fig. 18 is a circuit diagram showing an example of a heating operation mode in the air conditioning apparatus 100 according to embodiment 4. Note that the dashed arrows shown in Figs. 17 and 18 indicate the flow of the heat transfer medium. Furthermore, the temperatures of the heat transfer medium shown in Figs. 17 and 18 are merely examples and are not limited to the temperatures shown in Figs. 17 and 18. In the cooling operation mode and the heating operation mode of the air conditioning apparatus 100, operation of the second refrigerant circuit 20 of the relay unit 2 is stopped.

[0220] In the cooling operation mode and the heating operation mode of the air conditioning apparatus 100, the first flow path switching valve 331 of the intermediate relay unit 300 is opened and the second flow path switching valve 332 is closed. In the cooling operation mode and the heating operation mode of the air conditioning apparatus 100 shown in Figures 17 and 18, the second flow path switching valve 332 is closed, so that the heat transfer medium does not flow through the intermediate fourth flow path 354.

[0221] The heat transfer medium sent out from the heat source unit 1 flows into the interior of the intermediate main body unit 320 from the first intermediate connection part 391. The heat transfer medium that has flowed into the interior of the intermediate main body unit 320 passes through the first intermediate flow path 351, passes through the three first intermediate heat medium flow path switching devices 311, and flows out from the third intermediate connection part 393 of the intermediate relay unit 300. The heat transfer medium that has flowed out from the third intermediate connection part 393 of the intermediate relay unit 300 passes through the relay unit 2 and heads toward the load device 3.

[0222] The heat transfer medium that has passed through the load device 3 passes through the relay unit 2 and flows into the interior of the intermediate main body unit 320 from the fourth intermediate connection part 394. The heat transfer medium that has flowed into the interior of the intermediate main body unit 320 passes through the third intermediate flow path 353 and the first flow path switching valve 331, flows out from the second intermediate connection part 392, and heads toward the heat source unit 1.

[0223] Figure 19 is a circuit diagram showing an example of a cooling-dominated operation mode in Modification 2 of the air conditioning apparatus 100 pertaining to Embodiment 4. Figure 20 is a circuit diagram showing an example of a heating-dominated operation mode in Modification 2 of the air conditioning apparatus 100 pertaining to Embodiment 4. In Modification 2 of the air conditioning apparatus 100 pertaining to Embodiment 4, the configuration of the internal flow path of the intermediate relay unit 300 differs from that of the air conditioning apparatus 100 shown in Figures 15 and 16. Note that the same components as those in the air conditioning apparatus 100 described in Embodiments 1 to 4 are given the same reference numerals, and their description will be omitted as appropriate.

[0224] The intermediate repeater 300 has an intermediate first flow path 351 that branches at one end to form an intermediate first connection portion 391 and at the other end to form multiple intermediate third connection portions 393. The intermediate repeater 300 also has an intermediate second flow path 352 that branches at one end to form an intermediate second connection portion 392 and at the other end to form multiple intermediate fourth connection portions 394. The intermediate repeater 300 also has an intermediate fifth flow path 355 that branches at one end to form multiple intermediate third connection portions 393 and at the other end to form multiple intermediate fourth connection portions 394.

[0225] The intermediate relay 300 has a plurality of flow path switching valves 330 serving as on-off valves. The plurality of flow path switching valves 330 include, for example, a first flow path switching valve 331 and a second flow path switching valve 332.

[0226] The first flow path switching valve 331 is provided in the intermediate second flow path 352, in a portion between the intermediate first connection part 391 and a branching portion of the flow path connected to the second intermediate heat medium flow path switching device 312. The second flow path switching valve 332 is provided in the intermediate fifth flow path 355, in a portion between a branching portion of the flow path connected to the first intermediate heat medium flow path switching device 311 and a branching portion of the flow path connected to the second intermediate heat medium flow path switching device 312.

[0227] The first intermediate flow path 351, the second intermediate flow path 352, and the fifth intermediate flow path 355 form a flow path through which the heat transfer medium flows inside the intermediate relay device 300. The first intermediate flow path 351, the second intermediate flow path 352, and the fifth intermediate flow path 355 form a part of the heat transfer medium circuit 71 inside the intermediate relay device 300.

[0228] The three first intermediate heat medium flow switching devices 311 are provided at the junction of the first intermediate flow path 351 and the fifth intermediate flow path 355 to switch the flow path of the heat transfer medium. The three second intermediate heat medium flow switching devices 312 are provided at the junction of the second intermediate flow path 352 and the fifth intermediate flow path 355 to switch the flow path of the heat transfer medium.

[0229] The temperatures of the heat transfer medium and the like shown in Figures 19 and 20 are examples and are not limited to the temperatures shown in Figures 19 and 20. In the cooling-dominated operation mode of the air conditioning apparatus 100 shown in Figure 19, operation of the second refrigerant circuit 20 of the relay unit 2A is stopped, and the second refrigerant circuits 20 of the relay units 2B and 2C are operating in the heating operation mode. In the heating-dominated operation mode of the air conditioning apparatus 100 shown in Figure 20, operation of the second refrigerant circuit 20 of the relay unit 2A is stopped, and the second refrigerant circuits 20 of the relay units 2B and 2C are operating in the cooling operation mode.

[0230] In the cooling-dominated operation mode and the heating-dominated operation mode of the air conditioning apparatus 100, the first flow path switching valve 331 and the second flow path switching valve 332 of the intermediate relay unit 300 are open.

[0231] The heat transfer medium sent out from the heat source unit 1 flows into the interior of the intermediate main body unit 320 from the first intermediate connection unit 391. The heat transfer medium that has flowed into the interior of the intermediate main body unit 320 passes through the first intermediate flow path 351, passes through the two first intermediate heat medium flow path switching devices 311, and flows out from the third intermediate connection unit 393 of the intermediate relay unit 300. The heat transfer medium that has flowed out from the third intermediate connection unit 393 of the intermediate relay unit 300 passes through the relay unit 2A and the relay unit 2C and heads toward each load device 3.

[0232] The heat transfer medium that has passed through each load device 3 passes through the relay unit 2A and the relay unit 2C and flows into the intermediate main body unit 320 from the fourth intermediate connection unit 394. The heat transfer medium that has flowed into the intermediate main body unit 320 passes through the fifth intermediate flow path 355 and the second flow path switching valve 332, passes through one first intermediate heat medium flow path switching device 311, and flows out from the third intermediate connection unit 393 of the intermediate relay unit 300. The heat transfer medium that has flowed out from the third intermediate connection unit 393 of the intermediate relay unit 300 passes through the relay unit 2B and heads toward the load device 3.

[0233] The heat transfer medium that has passed through the load device 3 passes through the relay unit 2B and flows into the interior of the intermediate main body unit 320 from the fourth intermediate connection part 394. The heat transfer medium that has flowed into the interior of the intermediate main body unit 320 passes through the second intermediate flow path 352 and the first flow path switching valve 331, flows out from the second intermediate connection part 392, and heads toward the heat source unit 1.

[0234] 19 , when the load device 3 connected to the relay unit 2 is cooling-only or a combination of cooling and heating, as in the case of relay units 2A and 2C, the heat transfer medium sent out from the heat source unit 1 flows into the relay unit 2. Also, when the load device 3 connected to the relay unit 2 is cooling-only or a combination of cooling and heating, as in the case of relay units 2A and 2C, the heat transfer medium sent out from the heat source unit 1 flows into the load device 3 via the intermediate relay unit 300 and relay unit 2.

[0235] In the air conditioning apparatus 100, when the load device 3 connected to the relay device 2 is only for heating, as in the case of the relay device 2B, the heat transfer medium that flows out of the load device 3 and returns to the intermediate relay device 300 from the relay devices 2A and 2C flows into the relay device 2B via the intermediate relay device 300. The heat transfer medium that flows into the relay device 2B does not head toward the load device 3, but passes through the second intermediate heat exchanger 28, exchanges heat with the refrigerant flowing in the second refrigerant circuit 20, returns to the intermediate relay device 300, and returns to the heat source device 1 via the intermediate relay device 300.

[0236] 20 , when the load device 3 connected to the relay unit 2 is for heating only or for both heating and cooling, as in the case of relay units 2A and 2C, the heat transfer medium sent out from the heat source unit 1 flows into the relay unit 2. Also, when the load device 3 connected to the relay unit 2 is for heating only or for both heating and cooling, as in the case of relay units 2A and 2C, the heat transfer medium sent out from the heat source unit 1 flows into the load device 3 via the intermediate relay unit 300 and the relay unit 2.

[0237] In the air conditioning apparatus 100, when the load device 3 connected to the relay device 2 is only cooling-capable, as in the case of the relay device 2B, the heat transfer medium that flows out of the load device 3 and returns to the intermediate relay device 300 from the relay devices 2A and 2C flows into the relay device 2B via the intermediate relay device 300. The heat transfer medium that flows into the relay device 2B does not head toward the load device 3, but passes through the second intermediate heat exchanger 28, exchanges heat with the refrigerant flowing in the second refrigerant circuit 20, returns to the intermediate relay device 300, and returns to the heat source device 1 via the intermediate relay device 300.

[0238] [Effects of the Air Conditioning Apparatus 100] The air conditioning apparatus 100 further includes an intermediate relay unit 300 between at least one heat source unit 1 and multiple relay units 2, the intermediate relay unit 300 having a flow rate adjustment mechanism 80A that adjusts the flow rate of the heat transfer medium flowing through each of the multiple relay units 2. Therefore, when multiple load devices 3 perform cooling and heating simultaneously, the air conditioning apparatus 100 according to embodiment 4 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall. The air conditioning apparatus 100 according to embodiment 4 can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall and improving comfort in the indoor space.

[0239] Furthermore, the intermediate relay 300 has a plurality of intermediate heat medium flow switching devices 310 that switch the flow path of the heat transfer medium and a plurality of flow switching valves 330 that serve as on-off valves. The flow rate adjustment mechanism 80A of the intermediate relay 300 includes a plurality of intermediate heat medium flow switching devices 310 and a plurality of flow switching valves 330. With this configuration, when multiple load devices 3 simultaneously perform cooling and heating, the air conditioning apparatus 100 according to the fourth embodiment can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall. The air conditioning apparatus 100 according to the fourth embodiment can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2, thereby achieving efficient operation overall and improving the comfort of the indoor space.

[0240] Embodiment 5. Figure 21 is a circuit diagram that shows a schematic diagram of an air conditioning apparatus 100 according to embodiment 5. Next, the air conditioning apparatus 100 according to embodiment 5 will be described with reference to Figure 21. Note that the same components as those in the air conditioning apparatus 100 described in embodiments 1 to 4 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0241] The air conditioning apparatus 100 according to embodiment 5 differs from the air conditioning apparatus 100 according to embodiment 1 in the connection mode of the multiple relay units 2 in the heat transfer medium circuit 71. In the air conditioning apparatus 100 according to embodiment 1, the multiple relay units 2 are arranged in parallel to one another in the flow path through which the heat transfer medium flows, driven by the first pump 11. In contrast, in the air conditioning apparatus 100 according to embodiment 5, the flow path through which the heat transfer medium flows, driven by the first pump 11, includes a portion where the multiple relay units 2 are arranged in series to one another.

[0242] The air conditioning apparatus 100 according to Embodiment 5 has a first on-off valve 84 and a second on-off valve 85. The first on-off valve 84 is provided in a portion of the first flow path 211 of the relay unit 2 between the first connection part 91 and the bypass flow path 78. The first on-off valve 84 is also provided in a portion of the first flow path 211 of the relay unit 2 between the first connection part 91 and a branch part of the first flow path 211 and a fifth flow path 215 (described later).

[0243] The second on-off valve 85 is provided in the second flow path 212 of the relay unit 2, in a portion between the second connection part 92 and the second intermediate heat exchanger 28. The second on-off valve 85 is also provided in the second flow path 212 of the relay unit 2, in a portion between the second connection part 92 and a branching part of the second flow path 212 and a sixth flow path 216 (described later).

[0244] The first on-off valve 84 and the second on-off valve 85 are controlled to open and close by the control device 40 or the like, thereby adjusting the flow rate of the heat transfer medium flowing in and out of the relay unit 2. The flow rate adjustment valve 81 is configured, for example, as a two-way valve, and is controlled to open and close by the control device 40. The flow rate adjustment valve 81 may be configured, for example, as a two-way valve whose valve opening (opening area) can be controlled. The first on-off valve 84 is controlled to open and close, thereby controlling the flow of the heat transfer medium flowing in and out of the first flow path 211. The second on-off valve 85 is controlled to open and close, thereby controlling the flow of the heat transfer medium flowing in and out of the second flow path 212.

[0245] In the air conditioning apparatus 100 according to embodiment 5 shown in Fig. 21 , the first on-off valve 84 of the relay unit 2A is open and the second on-off valve 85 of the relay unit 2A is closed. Also, in the air conditioning apparatus 100 according to embodiment 5 shown in Fig. 21 , the first on-off valve 84 of the relay unit 2B is closed and the second on-off valve 85 of the relay unit 2B is open. The number of relay units 2 is not limited to two. When the number of relay units 2 is three or more, there may be a relay unit 2 in which the first on-off valve 84 of the relay unit 2 is open and the second on-off valve 85 of the relay unit 2 is open.

[0246] Each of the multiple relay units 2 has a seventh connection portion 97 and an eighth connection portion 98 to which connection piping 70 for connecting adjacent relay units is connected. The seventh connection portion 97 and the eighth connection portion 98 are provided in the main body portion 120 and are portions of the main body portion 120 through which the heat transfer medium flows in and out. The connection piping 70 is connected to the seventh connection portion 97 and the eighth connection portion 98. The multiple relay units 2 are connected to each other via the connection piping 70 connected to the seventh connection portion 97 and the eighth connection portion 98. When the connection piping 70 is not connected, the seventh connection portion 97 and the eighth connection portion 98 are sealed so that the heat transfer medium does not flow in or out of the seventh connection portion 97 and the eighth connection portion 98.

[0247] The relay unit 2 has a fifth flow path 215, one end of which is the seventh connection part 97 and the other end of which is connected to the first flow path 211. The relay unit 2 has a sixth flow path 216, one end of which is the eighth connection part 98 and the other end of which is connected to the second flow path 212. The fifth flow path 215 and the sixth flow path 216 form a heat transfer medium circuit 71 inside the relay unit 2.

[0248] The plurality of relay units 2 are connected such that the sixth flow path 216 of one relay unit 2 is connected to the fifth flow path 215 of the other relay unit 2 via a connection pipe 70 that is connected to the seventh connection part 97 of one relay unit 2 and the eighth connection part 98 of the other relay unit 2. The plurality of relay units 2 are connected such that the second flow path 212 of one relay unit 2 is connected to the fifth flow path 215 of the other relay unit 2 by connecting the connection pipe 70 to the seventh connection part 97 of one relay unit 2 and the eighth connection part 98 of the other relay unit 2.

[0249] In the air conditioning device 100, a connection pipe 70 is connected to the seventh connection part 97 of one of the two relay units 2 and the eighth connection part 98 of the other relay unit 2, so that multiple relay units 2 are connected in series in the flow of the heat transfer medium.

[0250] 21 will be used to explain an example of how the heat transfer medium flows in the air conditioning apparatus 100. The heat transfer medium sent out from the heat source unit 1 flows into the relay unit 2A via the first connection part 91 of the relay unit 2A. The heat transfer medium that has flowed into the relay unit 2A passes through the first flow path 211, the first on-off valve 84 and the first heat medium flow switching device 60a, and flows out from the third connection part 93.

[0251] The heat transfer medium flowing out from the third connection part 93 of the relay unit 2A passes through the load-side heat exchanger 30 of the load device 3 and flows into the relay unit 2A from the sixth connection part 96 of the relay unit 2A. The heat transfer medium flowing into the relay unit 2A passes through the second flow path 212, the fourth heat medium flow switching device 60d and the second intermediate heat exchanger 28, and the sixth flow path 216 of the relay unit 2A, before flowing out from the eighth connection part 98 to the outside of the relay unit 2A.

[0252] Depending on the operation mode of the air conditioning apparatus 100, the heat transfer medium may flow through the relay unit 2A as follows: The heat transfer medium that has flowed into the relay unit 2A may pass through the first flow path 211, the bypass flow path 78, the second flow path 212, and the sixth flow path 216, pass through the first on-off valve 84, the heat medium bypass valve 25, and the second intermediate heat exchanger 28, and then flow out of the relay unit 2A from the eighth connection part 98.

[0253] The heat transfer medium that flows out of the relay unit 2A from the eighth connection part 98 flows into the relay unit 2B from the seventh connection part 97 of the relay unit 2B. The heat transfer medium that flows into the relay unit 2B passes through the fifth flow path 215 and the first flow path 211, passes through the first heat medium flow switching device 60a, and flows out from the third connection part 93.

[0254] The heat transfer medium flowing out from the third connection part 93 of the relay unit 2B passes through the load-side heat exchanger 30 of the load device 3 and flows into the relay unit 2B from the sixth connection part 96 of the relay unit 2A. The heat transfer medium flowing into the relay unit 2B passes through the second flow path 212, the fourth heat medium flow switching device 60d, the second intermediate heat exchanger 28, and the second on-off valve 85, flows out of the relay unit 2B from the second connection part 92 of the relay unit 2B, and heads toward the heat source unit 1.

[0255] Depending on the operation mode of the air conditioning apparatus 100, the heat transfer medium may flow through the relay unit 2B as follows: The heat transfer medium that has flowed into the relay unit 2B may pass through the fifth flow path 215, the first flow path 211, the bypass flow path 78, and the second flow path 212, pass through the heat medium bypass valve 25, the second intermediate heat exchanger 28, and the second on-off valve 85, and then flow out of the relay unit 2B from the second connection part 92.

[0256] [Operation and Effect of the Air Conditioning Apparatus 100] In the air conditioning apparatus 100, a plurality of relay units 2 are connected in series in the flow of the heat transfer medium by connecting the connection pipe 70 to the seventh connection part 97 of one of the two relay units 2 and the eighth connection part 98 of the other relay unit 2. With this configuration, the air conditioning apparatus 100 can cause the heat transfer medium that has passed through the second intermediate heat exchanger 28 of one relay unit 2 to flow into the second intermediate heat exchanger 28 of another relay unit 2. Therefore, with this configuration, the air conditioning apparatus 100 can use the temperature of the heat transfer medium flowing out of the relay unit 2 located at the front in the flow of the heat transfer medium in the second intermediate heat exchanger 28 of the relay unit 2 located at the rear.

[0257] Sixth Embodiment. Figure 22 is a circuit diagram that schematically illustrates an air conditioning apparatus 100 according to a sixth embodiment. Figure 23 is a circuit diagram that illustrates an example of a cooling operation mode in the air conditioning apparatus 100 according to the sixth embodiment. Figure 24 is a circuit diagram that illustrates an example of a heating operation mode in the air conditioning apparatus 100 according to the sixth embodiment. Figure 25 is a circuit diagram that illustrates an example of a cooling-dominated operation mode in the air conditioning apparatus 100 according to the sixth embodiment. Figure 26 is a circuit diagram that illustrates an example of a heating-dominated operation mode in the air conditioning apparatus 100 according to the sixth embodiment. Next, the air conditioning apparatus 100 according to the sixth embodiment will be described with reference to Figures 22 to 26. Note that the same components as those in the air conditioning apparatus 100 described in the first to fifth embodiments will be assigned the same reference numerals, and their description will be omitted as appropriate.

[0258] The air conditioning apparatus 100 according to Embodiment 6 differs from the air conditioning apparatus 100 according to Embodiment 1 in the way in which the heat source unit 1 and the relay unit 2 are connected. In the air conditioning apparatus 100 according to Embodiment 1, the heat transfer medium sent out from the heat source unit 1 flows into the interior of the relay unit 2 from a first connection 91 of the relay unit 2, and the heat transfer medium returning to the heat source unit 1 flows out from a second connection 92 of the relay unit 2 and heads toward the heat source unit 1. In the air conditioning apparatus 100 according to Embodiment 6, the heat transfer medium sent out from the heat source unit 1 flows into the interior of the relay unit 2 from the second connection 92 of the relay unit 2, and the heat transfer medium returning to the heat source unit 1 flows out from the first connection 91 of the relay unit 2 and heads toward the heat source unit 1.

[0259] 23 , the refrigeration cycle of the first refrigerant circuit 10 in the heat source unit 1 is in cooling operation, and the refrigeration cycle of the second refrigerant circuit 20 in the relay unit 2 is stopped. The low-temperature heat transfer medium discharged from the heat source unit 1 passes through the second intermediate heat exchanger 28 of the relay unit 2 and flows into the load device 3, which is an indoor unit. The heat transfer medium that has exchanged heat in the load-side heat exchanger 30 of the load device 3 passes through the relay unit 2 and flows into the first pump 11 of the heat source unit 1.

[0260] 24 , the air conditioning apparatus 100 performing heating operation has the refrigeration cycle of the first refrigerant circuit 10 in the heat source unit 1 performing heating operation, and the refrigeration cycle of the second refrigerant circuit 20 in the relay unit 2 stopped. The high-temperature heat transfer medium discharged from the heat source unit 1 passes through the second intermediate heat exchanger 28 of the relay unit 2 and flows into the load device 3, which is an indoor unit. The heat transfer medium that has exchanged heat in the load-side heat exchanger 30 of the load device 3 passes through the relay unit 2 and flows into the first pump 11 of the heat source unit 1.

[0261] In the air conditioning apparatus 100 performing cooling-dominant operation shown in Figure 25, the refrigeration cycle of the first refrigerant circuit 10 in the heat source unit 1 performs cooling operation, and the refrigeration cycle of the second refrigerant circuit 20 in the relay unit 2 performs heating operation. The third intermediate heat exchanger 29 of the relay unit 2 serves as a condenser. The low-temperature heat transfer medium output from the heat source unit 1 flows into the second intermediate heat exchanger 28 of the relay unit 2, where it is further cooled by the refrigerant in the second refrigerant circuit 20, and flows into the load device 3, which serves as an indoor unit. The heat transfer medium that has exchanged heat in the load-side heat exchanger 30 of the load device 3 flows into the first pump 11 of the heat source unit 1 via the relay unit 2.

[0262] As shown in relay unit 2B, when all of the load devices 3 connected to relay unit 2 are in heating operation, the low-temperature heat transfer medium leaving heat source unit 1 flows into the first pump 11 of heat source unit 1 via the second intermediate heat exchanger 28 and the heat medium bypass valve 25 of relay unit 2.

[0263] In the air conditioning apparatus 100 performing heating-dominated operation shown in Figure 26, the refrigeration cycle of the first refrigerant circuit 10 in the heat source unit 1 performs heating operation, and the refrigeration cycle of the second refrigerant circuit 20 in the relay unit 2 performs cooling operation. The third intermediate heat exchanger 29 of the relay unit 2 serves as an evaporator. The high-temperature heat transfer medium output from the heat source unit 1 flows into the second intermediate heat exchanger 28 of the relay unit 2, where it is further heated by the refrigerant in the second refrigerant circuit 20, and flows into the load device 3, which serves as an indoor unit. The heat transfer medium that has exchanged heat in the load-side heat exchanger 30 of the load device 3 flows into the first pump 11 of the heat source unit 1 via the relay unit 2.

[0264] As shown in relay unit 2B, when all of the load devices 3 connected to relay unit 2 are in cooling operation, the high-temperature heat transfer medium leaving heat source unit 1 flows into the first pump 11 of heat source unit 1 via the second intermediate heat exchanger 28 and the heat medium bypass valve 25 of relay unit 2.

[0265] 25 and 26 , the second refrigerant circuit 20 in the relay unit 2 is in operation, and the heat transfer medium from the heat source unit 1 is sent to the load device 3 through the second intermediate heat exchanger 28 of the second refrigerant circuit 20. In the air conditioning unit 100 of FIGS. 25 and 26 , the heat transfer medium returning from the load device 3 returns to the heat source unit 1 without passing through the second intermediate heat exchanger 28. The heat transfer medium water passing through the third intermediate heat exchanger 29 of the second refrigerant circuit 20 circulates only between the relay unit 2 and the load device 3. The air conditioning unit 100 uses the heat transfer medium circulating between the relay unit 2 and the load device 3 as a heat source for the second intermediate heat exchanger 28 via the second refrigerant circuit 20.

[0266] In the air conditioning apparatus 100 according to Embodiment 6, the flow direction of the heat transfer medium sent out from the heat source unit 1 is opposite to that of the air conditioning apparatus 100 according to Embodiment 1. In the air conditioning apparatus 100 according to Embodiment 6, in the multiple relay units 2, the first connector 91 and the heat source unit 1 are connected by the connection pipe 70 in the first flow path 211 so that the heat transfer medium flows from the third connector 93 and the fourth connector 94 side toward the first connector 91 side. In the air conditioning apparatus 100 according to Embodiment 6, the second connector 92 and the heat source unit 1 are connected by the connection pipe 70 in the second flow path 212 so that the heat transfer medium flows from the second connector 92 side toward the fifth connector 95 and the sixth connector 96 side.

[0267] [Effects of the Air Conditioning Apparatus 100] In the multiple relay units 2 of the air conditioning apparatus 100, the first connection 91 and the heat source unit 1 are connected in the first flow path 211 so that the heat transfer medium flows from the third connection 93 and the fourth connection 94 side toward the first connection 91 side. In the multiple relay units 2, the second connection 92 and the heat source unit 1 are connected in the second flow path 212 so that the heat transfer medium flows from the second connection 92 side toward the fifth connection 95 and the sixth connection 96 side. By having this configuration, the air conditioning apparatus 100 according to the sixth embodiment can efficiently operate the multiple relay units 2 in accordance with the thermal load of each relay unit 2 when multiple load devices 3 simultaneously perform cooling and heating, thereby enabling efficient operation overall.

[0268] The air conditioning apparatus 100 uses the heat transfer medium circulating between the relay unit 2 and the load device 3 as a heat source for the second intermediate heat exchanger 28 via the second refrigerant circuit 20. The air conditioning apparatus 100 can further cool the low-temperature heat transfer medium flowing out from the heat source unit 1 in the second intermediate heat exchanger 28 of the relay unit 2 and send it to the load device 3, thereby increasing the temperature of the heat transfer medium at the outlet portion of the heat source unit 1. Therefore, the air conditioning apparatus 100 can increase the temperature of the heat transfer medium at the inlet portion of the second intermediate heat exchanger 28, making it easier to avoid freezing.

[0269] Seventh Embodiment Fig. 27 is a schematic diagram illustrating an air conditioning apparatus 100 according to a seventh embodiment. Fig. 28 is a schematic diagram illustrating a modified example of the air conditioning apparatus 100 according to the seventh embodiment. Next, the air conditioning apparatus 100 according to the seventh embodiment will be described with reference to Fig. 27. Note that the same components as those in the air conditioning apparatus 100 described in the first to sixth embodiments are given the same reference numerals, and the description thereof will be omitted as appropriate.

[0270] As shown in Fig. 27 , two or more heat source units 1 may be installed. In the air conditioning apparatus 100, a plurality of heat source units 1 may be installed in parallel, and two connection pipes 70 connected to the relay unit 2 may branch out and be connected to each of the plurality of heat source units 1. As shown in Fig. 28 , two or more intermediate relay units 300 may be installed. As an example, in the air conditioning apparatus 100, a plurality of intermediate relay units 300 may be installed in parallel.

[0271] [Operation and effect of the air conditioning apparatus 100] Furthermore, the air conditioning apparatus 100 has a plurality of heat source units 1 installed in parallel, and two connection pipes 70 connected to a plurality of relay units 2 branch off and are connected to each of the plurality of heat source units 1. Furthermore, the air conditioning apparatus 100 has a plurality of relay units 2 installed in parallel, and two connection pipes 70 connected to a plurality of relay units 2 branch off and are connected to each of the plurality of relay units 2. Compared to air conditioning apparatuses that require two pipes each for cooling and heating, the air conditioning apparatus 100 requires fewer pipes, reducing the burden of piping work.

[0272] Although the air conditioning device 100 has been described above based on the embodiments, the air conditioning device 100 is not limited to the configuration of the above-described embodiments. Each of the above-described embodiments 1 to 7 can be implemented in combination with one another. The configuration of the air conditioning device 100 described above is an example, and other components may be included, or some components may be omitted. In short, the air conditioning device 100 includes a range of design modifications and application variations that are normally made by a person skilled in the art, as long as they do not deviate from the technical concept of the air conditioning device 100.

[0273] 1 Heat source unit, 2 Relay unit, 2A Relay unit, 2B Relay unit, 2C Relay unit, 3 Load device, 3A Load device, 3B Load device, 6 First flow path switching device, 7 Heat source side flow control valve, 8 Heat source side blower, 9 First intermediate heat exchanger, 10 First refrigerant circuit, 11 First pump, 12 First compressor, 13 Air heat exchanger, 20 Second refrigerant circuit, 21 Second pump, 22 Second compressor, 25 Heat medium bypass valve, 26 Second flow path switching device, 27 Relay unit flow control valve, 28 Second intermediate heat exchanger, 29 Third intermediate heat exchanger, 29a First inlet / outlet, 29b Second inlet / outlet, 30 Load side heat exchanger, 31 Load side blower, 40 Control device, 41 First refrigerant temperature sensor, 42 Second refrigerant temperature sensor, 43 First heat medium temperature sensor, 44 Second heat medium temperature sensor, 60 Heat medium flow switching device, 60a First heat medium flow switching device, 60b Second heat medium flow switching device, 60c Third heat medium flow switching device, 60d Fourth heat medium flow switching device, 60e Fifth heat medium flow switching device, 60f Sixth heat medium flow switching device, 70 Connection pipe, 71 Heat transfer medium circuit, 75 First heat medium circuit, 76 Second heat medium circuit, 77 Third heat medium circuit, 78 Bypass flow path, 80 Flow rate adjustment mechanism, 80A Flow rate adjustment mechanism, 81 Flow rate adjustment valve, 82 Circulation pump, 84 First on-off valve, 85 Second on-off valve, 91 First connection part, 92 Second connection part, 93 Third connection part, 94 Fourth connection part, 95 Fifth connection part, 96 Sixth connection part, 97 Seventh connection part, 98 Eighth connection part, 100 Air conditioning apparatus, 120 Main body, 200 Building, 211 First flow path, 212 Second flow path, 213 Third flow path, 214 Fourth flow path, 215 Fifth flow path, 216 Sixth flow path, 300 Intermediate relay, 310 Intermediate heat medium flow path switching device, 311 First intermediate heat medium flow path switching device, 312 Second intermediate heat medium flow path switching device, 320 Intermediate main body, 330 Flow path switching valve, 331 First flow path switching valve, 332 Second flow path switching valve, 351 First intermediate flow path, 352 Second intermediate flow path, 353 Third intermediate flow path, 354 Fourth intermediate flow path, 355 Fifth intermediate flow path, 391 First intermediate connection part, 392 Second intermediate connection part, 393 Third intermediate connection part, 394 Fourth intermediate connection part.

Claims

1. A heat source system comprising: at least one heat source machine; a plurality of relay machines connected to the at least one heat source machine; a plurality of load devices connected to the plurality of relay machines; and a plurality of connection pipes connecting the at least one heat source machine, the plurality of relay machines, and the plurality of load devices; wherein the at least one heat source machine comprises: a first refrigerant circuit through which a refrigerant circulates, the first refrigerant circuit having: a first intermediate heat exchanger that performs heat exchange between the refrigerant flowing in the first refrigerant circuit and a heat transfer medium flowing therethrough; and an air heat exchanger that performs heat exchange between the refrigerant flowing in the first refrigerant circuit and air; and the plurality of relay machines comprise: a second refrigerant circuit through which a refrigerant circulates, the second refrigerant circuit having: a second intermediate heat exchanger that performs heat exchange between the refrigerant flowing in the second refrigerant circuit and a heat transfer medium flowing therethrough; and a third intermediate heat exchanger that performs heat exchange between the refrigerant flowing in the second refrigerant circuit and a heat transfer medium flowing therethrough; An air conditioning apparatus configured such that a heat transfer medium flows between the at least one heat source unit, the plurality of relay units, and at least one of the plurality of load devices via the plurality of connecting pipes, and the flow rate of the heat transfer medium flowing through each of the plurality of relay units is adjusted between the plurality of relay units.

2. An air conditioning apparatus as described in claim 1, wherein each of the plurality of relay units has a flow rate adjusting mechanism that adjusts the flow rate of the heat transfer medium flowing through each of the plurality of relay units between the plurality of relay units.

3. Each of the multiple relay units has: a first connection part and a second connection part connected to the multiple connection pipes on the heat source unit side; a third connection part, a fourth connection part, a fifth connection part, and a sixth connection part connected to the multiple connection pipes on the multiple load devices side; a first flow path branched at one end to be the first connection part and the other end to be the third connection part and the fourth connection part; a second flow path branched at one end to be the second connection part and, via the second intermediate heat exchanger, at the other end to be the fifth connection part and the sixth connection part; a third flow path branched at one end to be a first inlet / outlet for the heat transfer medium in the third intermediate heat exchanger and the other end to be the third connection part and the fourth connection part; and a fourth flow path branched at one end to be a second inlet / outlet for the heat transfer medium in the third intermediate heat exchanger and the other end to be the fifth connection part and the sixth connection part. a first heat medium flow switching device provided at a junction of one branch of the first flow path and one branch of the third flow path, for switching the flow path of the heat transfer medium flowing through the third connection part; a second heat medium flow switching device provided at a junction of the other branch of the first flow path and the other branch of the third flow path, for switching the flow path of the heat transfer medium flowing through the fourth connection part; a third heat medium flow switching device provided at a junction of one branch of the second flow path and one branch of the fourth flow path, for switching the flow path of the heat transfer medium flowing through the fifth connection part; and a fourth heat medium flow switching device provided at a junction of the other branch of the second flow path and the other branch of the fourth flow path, for switching the flow path of the heat transfer medium flowing through the sixth connection part. a bypass flow path having a heat medium bypass valve that adjusts a flow rate of the heat transfer medium, the bypass flow path having one end connected to a portion in the first flow path between the first connection part and the first heat medium flow switching device and the second heat medium flow switching device, and the other end connected to a portion in the second flow path between the second intermediate heat exchanger and the third heat medium flow switching device and the fourth heat medium flow switching device, wherein the flow rate adjustment mechanism includes the first heat medium flow switching device, the second heat medium flow switching device, the third heat medium flow switching device, the fourth heat medium flow switching device, and the bypass flow path having the heat medium bypass valve.

4. An air conditioning apparatus as described in claim 3, wherein a flow rate adjustment valve for adjusting the flow rate of the heat transfer medium is provided in a portion between the first connection portion and the bypass flow path in the first flow path of the plurality of relay devices, and the flow rate adjustment mechanism includes the first heat medium flow path switching device, the second heat medium flow path switching device, the third heat medium flow path switching device, the fourth heat medium flow path switching device, the bypass flow path having the heat medium bypass valve, and the flow rate adjustment valve.

5. The air conditioning apparatus of claim 3, wherein the first flow path of the plurality of relay units is provided with a circulation pump that circulates the heat transfer medium so that the heat transfer medium flows between the heat source unit, the relay unit, and at least one of the plurality of load devices via the plurality of connecting pipes, and the flow rate adjustment mechanism includes the first heat medium flow path switching device, the second heat medium flow path switching device, the third heat medium flow path switching device, the fourth heat medium flow path switching device, the bypass flow path having the heat medium bypass valve, and the circulation pump.

6. An air conditioning apparatus according to any one of claims 3 to 5, further comprising an intermediate relay unit between said at least one heat source unit and said plurality of relay units, said intermediate relay unit being equipped with said flow rate adjustment mechanism for adjusting the flow rate of the heat transfer medium flowing through each of said plurality of relay units.

7. An air conditioning apparatus as described in claim 6, wherein the intermediate relay has a plurality of intermediate heat medium flow path switching devices that switch the flow path of the heat transfer medium and a plurality of flow path switching valves that serve as open / close valves, and the flow rate adjustment mechanism of the intermediate relay includes the plurality of intermediate heat medium flow path switching devices and the plurality of flow path switching valves.

8. An air conditioning apparatus according to any one of claims 3 to 7, wherein the flow rate adjustment mechanism adjusts the flow rate of the heat transfer medium flowing through each of the plurality of relay units according to the thermal load of the plurality of load devices.

9. The air conditioning apparatus according to any one of claims 3 to 8, wherein the at least one heat source unit, at least one of the plurality of relay units, and at least one of the plurality of load devices are connected by the plurality of connecting pipes to form at least one first heat medium circuit through which a heat transfer medium circulates; the at least one of the plurality of relay units and at least one of the plurality of load devices are connected by the plurality of connecting pipes to form at least one second heat medium circuit through which a heat transfer medium circulates; the at least one heat source unit and at least one of the plurality of relay units are connected by the plurality of connecting pipes to form at least one third heat medium circuit through which a heat transfer medium circulates; and the first heat medium flow switching device, the second heat medium flow switching device, the third heat medium flow switching device, the fourth heat medium flow switching device, and the heat medium bypass valve switch the flow path of the heat transfer medium to form the first heat medium circuit, the second heat medium circuit, and the third heat medium circuit.

10. The air conditioning apparatus according to any one of claims 3 to 8, wherein the first intermediate heat exchanger, at least one of the load side heat exchangers of the plurality of load devices, and at least one of the second intermediate heat exchangers are connected by the plurality of connecting pipes to form at least one first heat medium circuit through which a heat transfer medium circulates; the third intermediate heat exchanger and at least one of the load side heat exchangers of the plurality of load devices are connected by the plurality of connecting pipes to form at least one second heat medium circuit through which a heat transfer medium circulates; the first intermediate heat exchanger and at least one of the second intermediate heat exchangers are connected by the plurality of connecting pipes to form at least one third heat medium circuit through which a heat transfer medium circulates; and the flow paths of the heat transfer medium to form the first heat medium circuit, the second heat medium circuit, and the third heat medium circuit are switched by the first heat medium flow switching device, the second heat medium flow switching device, the third heat medium flow switching device, the fourth heat medium flow switching device, and the heat medium bypass valve.

11. An air conditioning apparatus according to any one of claims 3 to 10, wherein the plurality of relay units are such that, in the first flow path, the first connection part and the heat source unit are connected so that the heat transport medium flows from the first connection part side to the third and fourth connection part side, and in the second flow path, the second connection part and the heat source unit are connected so that the heat transport medium flows from the fifth and sixth connection part side to the second connection part side.

12. An air conditioning apparatus according to any one of claims 3 to 10, wherein the plurality of relay units are connected between the first connection part and the heat source unit in the first flow path so that the heat transport medium flows from the third connection part and the fourth connection part side to the first connection part side, and wherein the second connection part and the heat source unit are connected in the second flow path so that the heat transport medium flows from the second connection part side to the fifth connection part and the sixth connection part side.

13. An air conditioning apparatus according to any one of claims 1 to 12, wherein the heat source unit and the relay unit are connected by two of the connection pipes, and the relay unit and each of the plurality of load devices are connected by two of the connection pipes.

14. An air conditioning apparatus according to any one of claims 1 to 13, wherein in one or more of the plurality of relay units, heat exchange occurs between the heat transfer medium flowing through the second intermediate heat exchanger and the refrigerant in the second refrigerant circuit, and heat exchange occurs between the heat transfer medium flowing through the third intermediate heat exchanger and the refrigerant in the second refrigerant circuit, and the heat transfer medium flowing through the second intermediate heat exchanger, via the refrigerant flowing in the second refrigerant circuit, generates a heat transfer medium in the third intermediate heat exchanger having a temperature range different from that of the heat transfer medium flowing through the second intermediate heat exchanger.

15. An air conditioning apparatus according to any one of claims 1 to 14, wherein the second refrigerant circuit of the plurality of relay units either absorbs heat from a first heat transfer medium flowing through one of the two connecting pipes connecting the heat source unit and the relay unit, and provides heat to a second heat transfer medium flowing in at least one of the plurality of load devices, or provides heat to the first heat transfer medium flowing in one of the two connecting pipes connecting the heat source unit and the relay unit, and absorbs heat from the second heat transfer medium flowing in at least one of the plurality of load devices, thereby changing the temperatures of the first heat transfer medium and the second heat transfer medium.

16. An air conditioning system as described in any one of claims 1 to 15, comprising a control device that controls the at least one heat source unit, the plurality of relay units, and the plurality of load devices, wherein the control device controls all of the operating modes of the at least one heat source unit to be operating modes that have a larger thermal load than the overall thermal load of the system, and controls and operates at least one of the plurality of relay units to be operating modes that have a smaller thermal load than the overall thermal load of the system.

17. An air conditioning apparatus according to any one of claims 3 to 12, wherein the connecting pipes are connected to the seventh connecting part of one of the plurality of relay units and the eighth connecting part of the other of the plurality of relay units; a fifth flow path having one end which is the seventh connecting part and the other end which is connected to the first flow path; a sixth flow path having one end which is the eighth connecting part and the other end which is connected to the second flow path; a first on-off valve provided in the first flow path, in a portion between the first connecting part and a portion where the fifth flow path and the first flow path branch; and a second on-off valve provided in the second flow path, in a portion between the second connecting part and a portion where the sixth flow path and the second flow path branch; and wherein the connecting pipes are connected to the seventh connecting part of one of the two relay units and the eighth connecting part of the other relay unit, so that the plurality of relay units are connected in series in the flow of the heat transfer medium.

18. An air conditioning system as described in any one of claims 1 to 17, wherein the heat source units are installed in parallel, and the two connection pipes connected to the relay unit branch off and are connected to each of the heat source units.

Images