Air-conditioning device

Abstract

This air-conditioning device comprises a heat source machine, a first relay, a plurality of second relays, a plurality of load devices, and a plurality of connection pipes. The heat source machine comprises a first refrigerant circuit. The first refrigerant circuit has a first intermediate heat exchanger and a heat source-side heat exchanger. The first relay comprises a second refrigerant circuit. The second refrigerant circuit has a second intermediate heat exchanger and a third intermediate heat exchanger. The second relay comprises a third refrigerant circuit. The third refrigerant circuit has a fourth intermediate heat exchanger and a fifth intermediate heat exchanger. A heat transfer medium flows between the heat source machine, the first relay, the second relays, and the load devices via the plurality of connection pipes.

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, at least one first relay unit connected to the at least one heat source unit, a plurality of second relay units connected to the at least one first relay unit, a plurality of load devices connected to the plurality of second relay units, and a plurality of connection pipes connecting the at least one heat source unit, the at least one first relay unit, the plurality of second 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 a heat source side heat exchanger that exchanges heat between the refrigerant flowing in the first refrigerant circuit and air, and the at least one first relay unit includes a second refrigerant circuit through which the 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 a heat source side heat exchanger that exchanges heat between the refrigerant flowing in the first refrigerant circuit and air, The second refrigerant circuit has a second intermediate heat exchanger in which the refrigerant flowing in the second refrigerant circuit exchanges heat with the heat transfer medium flowing therein, and a third intermediate heat exchanger in which the refrigerant flowing in the second refrigerant circuit exchanges heat with the heat transfer medium flowing therein, and the plurality of second relay units have a third refrigerant circuit in which a refrigerant circulates, and the third refrigerant circuit has a fourth intermediate heat exchanger in which the refrigerant flowing in the third refrigerant circuit exchanges heat with the heat transfer medium flowing therein, and a fifth intermediate heat exchanger in which the refrigerant flowing in the third refrigerant circuit exchanges heat with the heat transfer medium flowing therein, and the heat transfer medium flows between at least one heat source unit, at least one first relay unit, at least one of the plurality of second relay units, and at least one of the plurality of load devices via a plurality of connecting pipes.

[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, the second refrigerant circuit provided in the first relay unit, and the third refrigerant circuit provided in the second relay unit, respectively, thereby reducing the number of pipes connected to the heat source unit.

[0008] 1 is a configuration diagram schematically showing 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 first heat medium circuit in an air conditioning apparatus according to Embodiment 1. FIG. 4 is a circuit diagram showing an example of a second heat medium circuit in an air conditioning apparatus according to Embodiment 1. FIG. 5 is a circuit diagram showing an example of a third heat medium circuit in an air conditioning apparatus according to Embodiment 1. FIG. 6 is a circuit diagram showing an example of an air conditioning apparatus according to Embodiment 1. FIG. 7 is a circuit diagram showing an example of a cooling operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 8 is a circuit diagram showing an example of a heating operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 9 is a circuit diagram showing an example of a cooling-dominated operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 10 is a circuit diagram showing an example of a heating-dominated operation mode in an air conditioning apparatus according to Embodiment 1. FIG. 11 is a configuration diagram schematically showing a first modified example of an air conditioning apparatus according to Embodiment 1. FIG. 12 is a configuration diagram schematically showing a second modified example of an air conditioning apparatus according to Embodiment 1. FIG. 13 is a configuration diagram schematically showing an air conditioning apparatus according to a comparative example. FIG. 14 is a configuration diagram schematically showing an air conditioning apparatus according to Embodiment 2.

[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 solid and dashed arrows shown in Fig. 2 indicate the flow of a heat transfer medium. Furthermore, the temperatures of the heat transfer medium shown in Fig. 2 are merely examples, and are not limited to the temperatures shown in Fig. 2. The air conditioning apparatus 100 will be described using Figs. 1 and 2.

[0011] The air conditioning apparatus 100 is an apparatus for heating or cooling a room by transferring heat between the outside air and the indoor air via a refrigerant and a heat transfer medium. As shown in Figures 1 and 2, the air conditioning apparatus 100 according to the first embodiment includes a heat source unit 1, a first relay unit 4 connected to the heat source unit 1, a second relay unit 2 connected to the first relay unit 4, and a load device 3 connected to the second relay unit 2.

[0012] The air conditioning apparatus 100 includes a plurality of connection pipes 70 that connect the heat source unit 1, the first relay unit 4, the second relay unit 2, and the load device 3. The air conditioning apparatus 100 also includes a control device 6. The components that make up the heat source unit 1, the first relay unit 4, the second relay unit 2, and the load device 3 are controlled by the control device 6.

[0013] In the air conditioning device 100, a heat transfer medium flows between at least one heat source unit 1, at least one first relay unit 4, at least one of the multiple second relay units 2, and at least one of the multiple load devices 3 via multiple connection pipes 70.

[0014] The air conditioning apparatus 100 is a system that is composed of a heat source unit 1, multiple second relay units 2, and a group of load devices 3, and generates chilled or hot water through a refrigeration cycle in the heat source unit 1 and the second relay unit 2, and transports heat between each unit using the chilled or hot water. The air conditioning apparatus 100 also has a first relay unit 4, which has a built-in refrigeration cycle that generates chilled or hot water, installed between the heat source unit 1 and the second relay unit 2, and transports heat between each unit using the chilled or hot water.

[0015] [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 in Figures 1 and 2, the air conditioning apparatus 100 includes one heat source unit 1, but the air conditioning apparatus 100 may also include multiple heat source units 1. The temperatures of 16°C to 43°C shown in Figure 2 are one example of the temperature of air discharged from the heat source unit 1, which is an outdoor unit.

[0016] All of the at least one heat source unit 1 include a first refrigerant circuit 10 through which a refrigerant circulates. The first refrigerant circuit 10 has a first intermediate heat exchanger 11 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with a heat transfer medium flowing therein, and a heat source side heat exchanger 14 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with air. The heat source unit 1 has the first refrigerant circuit 10 through which a refrigerant circulates, the first intermediate heat exchanger 11 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with a heat transfer medium flowing therein, and the heat source side heat exchanger 14 through which the refrigerant flowing through the first refrigerant circuit 10 exchanges heat with air.

[0017] 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 13, a heat source side heat exchanger 14, a first expansion mechanism 15, and a first intermediate heat exchanger 11 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.

[0018] 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 6. The refrigerant discharged from the first compressor 12 flows into the heat source side heat exchanger 14 and the first intermediate heat exchanger 11 via the first flow switching device 13.

[0019] The first flow switching device 13 is, for example, a four-way valve and has a function of switching the refrigerant flow path. For example, during cooling operation of the air conditioning apparatus 100, the first flow switching device 13 switches the refrigerant flow path to connect the refrigerant discharge side of the first compressor 12 to the heat source side heat exchanger 14 and to connect the refrigerant suction side of the first compressor 12 to the first intermediate heat exchanger 11. Meanwhile, during heating operation of the air conditioning apparatus 100, the first flow switching device 13 switches the refrigerant flow path to connect the refrigerant discharge side of the first compressor 12 to the first intermediate heat exchanger 11 and to connect the refrigerant suction side of the first compressor 12 to the heat source side heat exchanger 14. The first flow switching device 13 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 13.

[0020] The heat source-side heat exchanger 14 functions as a condenser during cooling operation, for example. The heat source-side heat exchanger 14 also functions as an evaporator during heating operation, for example. The heat source-side heat exchanger 14 draws in outdoor air using the heat source-side blower 16, exchanges heat with the refrigerant flowing inside, and discharges the air to the outside.

[0021] The first expansion mechanism 15 reduces the pressure of the refrigerant flowing through the first refrigerant circuit 10 to expand it, and is configured, for example, by an electronic expansion valve whose opening degree is variably controlled.

[0022] The first intermediate heat exchanger 11 exchanges heat between the heat transfer medium and the refrigerant. The first intermediate heat exchanger 11 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 11 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.

[0023] The first intermediate heat exchanger 11 functions as an evaporator during cooling operation, for example, and exchanges heat between the refrigerant flowing out from the first expansion mechanism 15 and the heat transfer medium, evaporating the refrigerant to vaporize it, and cooling the heat transfer medium. The first intermediate heat exchanger 11 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.

[0024] 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.

[0025] A heat transfer medium flows through the heat transfer medium circuit 71. The heat transfer medium may be, for example, water, brine, or a mixture of brine and water. The temperatures of 7°C, 9°C, 10°C, 11°C, 12°C, 40°C, and 45°C shown in FIG. 2 are examples of the temperature of the heat transfer medium. However, the temperature of the heat transfer medium is not limited to these temperatures.

[0026] [First relay unit 4] The air conditioning apparatus 100 includes at least one first relay unit 4 connected to at least one heat source unit 1. The first relay unit 4 is installed, for example, inside the building 200. Note that although the air conditioning apparatus 100 includes one first relay unit 4 in Figures 1 and 2, the air conditioning apparatus 100 may also include multiple first relay units 4 (see Figures 11 and 12). As shown in Figure 2, the first relay unit 4 may include a chilled or hot water generating unit 401 and a branching unit 402.

[0027] All of the at least one first relay unit 4 include a second refrigerant circuit 40 through which a refrigerant circulates. The second refrigerant circuit 40 includes a second intermediate heat exchanger 41 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 40 and the heat transfer medium flowing therein, and a third intermediate heat exchanger 42 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 40 and the heat transfer medium flowing therein. The first relay unit 4 includes the second refrigerant circuit 40 through which a refrigerant circulates, the second intermediate heat exchanger 41 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 40 and the heat transfer medium flowing therein, and the third intermediate heat exchanger 42 that exchanges heat between the refrigerant flowing through the second refrigerant circuit 40 and the heat transfer medium flowing therein. The first relay unit 4 is connected to a flow path formed by a plurality of connection pipes 70, and may include a plurality of flow path switching valves 8 that switch the flow path of the heat transfer medium.

[0028] The first relay unit 4 has a second refrigerant circuit 40 in which refrigerant circulates in a chilled or hot water generating unit 401. The second refrigerant circuit 40 has a configuration in which a second compressor 43, a second flow switching device 44, a second intermediate heat exchanger 41, a second expansion mechanism 45, and a third intermediate heat exchanger 42 are connected in this order by refrigerant piping. Note that the second refrigerant circuit 40 may include other components in addition to the above-described components, or may omit some components.

[0029] The second compressor 43 draws in low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges high-temperature, high-pressure refrigerant. The second compressor 43 is, for example, an inverter compressor and has basically the same configuration as the first compressor 12. The refrigerant discharged from the second compressor 43 flows into the second intermediate heat exchanger 41 or the third intermediate heat exchanger 42 via the second flow switching device 44.

[0030] The second flow path switching device 44 is, for example, a four-way valve and has the function of switching the refrigerant flow path. The second flow path switching device 44 has basically the same configuration as the first flow path switching device 13. For example, during cooling operation of the air conditioning apparatus 100, the second flow path switching device 44 switches the refrigerant flow path to connect the refrigerant discharge side of the second compressor 43 to the third intermediate heat exchanger 42 and to connect the refrigerant suction side of the second compressor 43 to the second intermediate heat exchanger 41. On the other hand, during heating operation of the air conditioning apparatus 100, the second flow path switching device 44 switches the refrigerant flow path to connect the refrigerant discharge side of the second compressor 43 to the second intermediate heat exchanger 41 and to connect the refrigerant suction side of the second compressor 43 to the third intermediate heat exchanger 42. The second flow path switching device 44 may be configured by combining two-way or three-way valves. The second refrigerant circuit 40 can switch between cooling and heating operation by the second flow path switching device 44.

[0031] The second expansion mechanism 45 reduces the pressure of the refrigerant circulating in the second refrigerant circuit 40 to expand it, and is configured, for example, by an electronic expansion valve whose opening degree is variably controlled.

[0032] The second intermediate heat exchanger 41 exchanges heat between the heat transfer medium and the refrigerant. The second intermediate heat exchanger 41 is a flow path of the heat transfer medium circuit 71 formed by the flow path of the second refrigerant circuit 40 and the connecting pipe 70. In other words, the second intermediate heat exchanger 41 is a component of the second refrigerant circuit 40 and a component of the heat transfer medium circuit 71 formed by the connecting pipe 70. In the second intermediate heat exchanger 41 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 40 and the heat transfer medium circulating through the heat transfer medium circuit 71 flow in counterflow directions to increase the heat exchange rate in the second intermediate heat exchanger 41.

[0033] When functioning as a condenser, the second intermediate heat exchanger 41 exchanges heat between the refrigerant flowing in from the second compressor 43 and the heat transfer medium circulating through the connecting pipe 70, condensing the refrigerant to liquefy or to form a gas-liquid two-phase mixture, and heating the heat transfer medium. When functioning as an evaporator, the second intermediate heat exchanger 41 exchanges heat between the refrigerant flowing out from the second expansion mechanism 45 and the heat transfer medium circulating through the connecting pipe 70, evaporating the refrigerant to vaporize it, and cooling the heat transfer medium.

[0034] The third intermediate heat exchanger 42 exchanges heat between the heat transfer medium and the refrigerant. The third intermediate heat exchanger 42 is a flow path of the heat transfer medium circuit 71 formed by the flow path of the second refrigerant circuit 40 and the connecting pipe 70. In other words, the third intermediate heat exchanger 42 is a component of the second refrigerant circuit 40 and a component of the heat transfer medium circuit 71 formed by the connecting pipe 70. In the third intermediate heat exchanger 42 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 40 and the heat transfer medium circulating through the heat transfer medium circuit 71 flow in counterflow directions to increase the heat exchange rate in the third intermediate heat exchanger 42.

[0035] When functioning as an evaporator, the third intermediate heat exchanger 42 exchanges heat between the refrigerant flowing out from the second expansion mechanism 45 and the heat transfer medium circulating through the connecting pipe 70, evaporating the refrigerant and cooling the heat transfer medium. When functioning as a condenser, the third intermediate heat exchanger 42 exchanges heat between the refrigerant flowing in from the second compressor 43 and the heat transfer medium circulating through the connecting pipe 70, condensing the refrigerant to liquefy or to form a two-phase gas-liquid state, and heating the heat transfer medium.

[0036] The second refrigerant circuit 40 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 first relay unit 4 is mainly installed indoors. The refrigerant filled in the second refrigerant circuit 40 is not limited to the above-mentioned refrigerants, and may be any refrigerant commonly used in air conditioners today, such as R410A or R32, R290, CO ２ NH ３For example, the refrigerant sealed in the second refrigerant circuit 40 may be, in consideration of safety, R290, NH ３ A flammable refrigerant such as olefin may be enclosed.

[0037] The amount of refrigerant circulating through the first refrigerant circuit 10 is greater than the amount of refrigerant circulating through the second refrigerant circuit 40. The amount of refrigerant circulated through the first refrigerant circuit 10 is, for example, 5 kg or less. The amount of refrigerant circulated through the second refrigerant circuit 40 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 40.

[0038] The first relay 4 has multiple flow path switching valves 8 at the branching section 402. The multiple flow path switching valves 8 are respectively provided in the first relay 4 at an outflow side of the heat transfer medium flowing from the first relay 4 to the second relay 2 and at an inflow side of the heat transfer medium flowing from the second relay 2 to the first relay 4. The flow path switching valves 8 are configured as, for example, three-way valves, and their opening and closing is controlled by the control device 6 or manually. The flow path switching valves 8 are also switched by the control device 6 or manually. The flow path switching valves 8 may also be configured as two-way valves or the like. The flow path switching valves 8 may also be configured as, for example, valves whose valve 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 second relay 2 is controlled by controlling the opening and closing of the flow path switching valves 8 provided in the first relay 4.

[0039] In the first relay unit 4, the plurality of flow path switching valves 8 are configured by six valves, namely, flow path switching valve 8a, flow path switching valve 8b, flow path switching valve 8c, flow path switching valve 8d, flow path switching valve 8e, and flow path switching valve 8f, but the number of flow path switching valves 8 is not limited to six. The number of flow path switching valves 8 in the first relay unit 4 may be less than six or more than six depending on the number of second relay units 2 connected to the first relay unit 4.

[0040] The flow path switching valves 8a, 8b, and 8c of the first relay unit 4 are arranged downstream of a second pump 46, which will be described later. The flow path switching valves 8a, 8b, and 8c are arranged downstream of the third intermediate heat exchanger 42 in the flow path of the heat transfer medium caused by the second pump 46. The flow path switching valves 8a, 8b, and 8c are arranged in parallel in the flow path through which the heat transfer medium caused by the second pump 46 flows.

[0041] The flow path switching valves 8a, 8b, and 8c are arranged downstream of a first pump 17, which will be described later. The flow path switching valves 8a, 8b, and 8c are arranged downstream of the first intermediate heat exchanger 11 in the flow of the heat transfer medium caused by the first pump 17. The flow path switching valves 8a, 8b, and 8c are arranged in parallel in the flow path through which the heat transfer medium caused by the first pump 17 flows.

[0042] The flow path switching valves 8a, 8b and 8c are connected at their upstream portions to the outlet portion of the first intermediate heat exchanger 11 and the outlet portion of the third intermediate heat exchanger 42 by the connecting pipe 70 and the internal flow path of the first relay unit 4.

[0043] The flow path switching valves 8a, 8b, and 8c are connected to the flow path switching valve 8 of the second relay unit 2. More specifically, the flow path switching valves 8a, 8b, and 8c are connected to the flow path switching valves 8g, 8h, and 8i of each second relay unit 2. The flow path switching valves 8a, 8b, and 8c of the first relay unit 4 are arranged upstream of the flow path switching valves 8g, 8h, and 8i of each second relay unit 2 in the flow of the heat transfer medium caused by the first pump 17 or the second pump 46. In the flow of the heat transfer medium caused by the first pump 17 or the second pump 46, the downstream portions of the flow path switching valves 8a, 8b, and 8c of the first relay unit 4 are connected to the upstream portions of the flow path switching valves 8g, 8h, and 8i of each second relay unit 2.

[0044] The flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f are arranged upstream of the second pump 46 with respect to the second pump 46. The flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f are arranged upstream of the third intermediate heat exchanger 42 in the flow path of the heat transfer medium caused by the second pump 46. The flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f are arranged in parallel in the flow path through which the heat transfer medium caused by the second pump 46 flows.

[0045] The flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f are arranged upstream of the first pump 17 with respect to the first pump 17. The flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f are arranged upstream of the second intermediate heat exchanger 41 in the flow path of the heat transfer medium caused by the first pump 17. The flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f are arranged in parallel in the flow path through which the heat transfer medium caused by the first pump 17 flows.

[0046] The flow path switching valves 8d, 8e, and 8f are connected at their downstream portions to the inlet side of the third intermediate heat exchanger 42 and the inlet side of the second intermediate heat exchanger 41 by the connecting piping 70 and the internal flow paths of the first relay unit 4.

[0047] The flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f are connected to the fourth intermediate heat exchanger 21 of each second relay unit 2. More specifically, the flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f of the first relay unit 4 are arranged downstream of the fourth intermediate heat exchanger 21 of each second relay unit 2 in the flow of the heat transfer medium caused by the first pump 17 or the second pump 46. In the flow of the heat transfer medium caused by the first pump 17 or the second pump 46, the upstream portions of the flow path switching valve 8d, the flow path switching valve 8e, and the flow path switching valve 8f of the first relay unit 4 are arranged to be connected to the downstream portion of the fourth intermediate heat exchanger 21.

[0048] [Second relay unit 2] The air conditioning apparatus 100 is equipped with a plurality of second relay units 2 connected to at least one first relay unit 4. The second relay units 2 are installed, for example, inside a building 200. Note that in FIGS. 1 and 2 , the air conditioning apparatus 100 is equipped with three second relay units 2: second relay unit 2A, second relay unit 2B, and second relay unit 2C, but the air conditioning apparatus 100 may be equipped with two second relay units 2, or four or more second relay units 2. As shown in FIG. 2 , the second relay unit 2 may have a chilled or hot water generating unit 201 and a branching unit 202.

[0049] All of the multiple second relay units 2 include a third refrigerant circuit 20 through which a refrigerant circulates. The third refrigerant circuit 20 includes a fourth intermediate heat exchanger 21 that exchanges heat between the refrigerant flowing through the third refrigerant circuit 20 and the heat transfer medium flowing therein, and a fifth intermediate heat exchanger 22 that exchanges heat between the refrigerant flowing through the third refrigerant circuit 20 and the heat transfer medium flowing therein. The second relay unit 2 includes the third refrigerant circuit 20 through which a refrigerant circulates, the fourth intermediate heat exchanger 21 that exchanges heat between the refrigerant flowing through the third refrigerant circuit 20 and the heat transfer medium flowing therein, and the fifth intermediate heat exchanger 22 that exchanges heat between the refrigerant flowing through the third refrigerant circuit 20 and the heat transfer medium flowing therein. The second relay unit 2 is connected to a flow path formed by a multiple number of connection pipes 70, and includes a multiple number of flow path switching valves 8 that switch the flow path of the heat transfer medium.

[0050] The second relay unit 2 has a third refrigerant circuit 20 in which refrigerant circulates in a chilled or hot water generating unit 201. The third refrigerant circuit 20 has a configuration in which a third compressor 23, a third flow switching device 24, a fourth intermediate heat exchanger 21, a third expansion mechanism 25, and a fifth intermediate heat exchanger 22 are connected in this order by refrigerant piping. Note that the third refrigerant circuit 20 may include other components in addition to the above-described components, or may omit some components.

[0051] The third compressor 23 draws in low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges high-temperature, high-pressure refrigerant. The third compressor 23 is, for example, an inverter compressor and has basically the same configuration as the first compressor 12. The refrigerant discharged from the third compressor 23 flows into the fourth intermediate heat exchanger 21 or the fifth intermediate heat exchanger 22 via a third flow switching device 24.

[0052] The third flow path switching device 24 is, for example, a four-way valve and has the function of switching the refrigerant flow path. The third flow path switching device 24 has basically the same configuration as the first flow path switching device 13. For example, during cooling operation of the air conditioning apparatus 100, the third flow path switching device 24 switches the refrigerant flow path to connect the refrigerant discharge side of the third compressor 23 to the fourth intermediate heat exchanger 21 and to connect the refrigerant suction side of the third compressor 23 to the fifth intermediate heat exchanger 22. On the other hand, during heating operation of the air conditioning apparatus 100, the third flow path switching device 24 switches the refrigerant flow path to connect the refrigerant discharge side of the third compressor 23 to the fifth intermediate heat exchanger 22 and to connect the refrigerant suction side of the third compressor 23 to the fourth intermediate heat exchanger 21. The third flow path switching device 24 may be configured by combining two-way valves or three-way valves. The third refrigerant circuit 20 can switch between cooling and heating operation by the third flow path switching device 24.

[0053] The third expansion mechanism 25 reduces the pressure of the refrigerant circulating in the third refrigerant circuit 20 to expand it, and is configured, for example, by an electronic expansion valve whose opening degree is variably controlled.

[0054] The fourth intermediate heat exchanger 21 exchanges heat between the heat transfer medium and the refrigerant. The fourth intermediate heat exchanger 21 is a flow path of the heat transfer medium circuit 71 formed by the flow path of the third refrigerant circuit 20 and the connecting pipe 70. In other words, the fourth intermediate heat exchanger 21 is a component of the third refrigerant circuit 20 and a component of the heat transfer medium circuit 71 formed by the connecting pipe 70. In the fourth intermediate heat exchanger 21 shown in FIG. 2 , particularly when functioning as a condenser, it is preferable to configure the pipes so that the refrigerant circulating through the third refrigerant circuit 20 and the heat transfer medium circulating through the heat transfer medium circuit 71 flow in counterflow directions to increase the heat exchange rate in the fourth intermediate heat exchanger 21.

[0055] When functioning as a condenser, the fourth intermediate heat exchanger 21 exchanges heat between the refrigerant flowing in from the third compressor 23 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 an evaporator, the fourth intermediate heat exchanger 21 exchanges heat between the refrigerant flowing out from the third expansion mechanism 25 and the heat transfer medium circulating through the connecting pipe 70, evaporates the refrigerant to vaporize it, and cools the heat transfer medium.

[0056] The fifth intermediate heat exchanger 22 exchanges heat between the heat transfer medium and the refrigerant. The fifth intermediate heat exchanger 22 is a flow path of the heat transfer medium circuit 71 formed by the flow path of the third refrigerant circuit 20 and the connecting pipe 70. In other words, the fifth intermediate heat exchanger 22 is a component of the third refrigerant circuit 20 and a component of the heat transfer medium circuit 71 formed by the connecting pipe 70. In the fifth intermediate heat exchanger 22 shown in FIG. 2 , particularly when functioning as a condenser, it is preferable to configure the pipes so that the refrigerant circulating through the third 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 fifth intermediate heat exchanger 22.

[0057] When functioning as an evaporator, the fifth intermediate heat exchanger 22 exchanges heat between the refrigerant flowing out from the third expansion mechanism 25 and the heat transfer medium circulating through the connecting pipe 70, evaporating the refrigerant and cooling the heat transfer medium. When functioning as a condenser, the fifth intermediate heat exchanger 22 exchanges heat between the refrigerant flowing in from the third compressor 23 and the heat transfer medium circulating through the connecting pipe 70, condensing the refrigerant to liquefy or to form a two-phase gas-liquid state, and heating the heat transfer medium.

[0058] The third 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 second relay unit 2 is mainly installed indoors. The refrigerant filled in the third refrigerant circuit 20 is not limited to the above-mentioned refrigerants, and may be a refrigerant that is currently commonly used in air conditioning, such as R410A or R32, or a refrigerant such as R290 or CO ２ NH ３For example, the refrigerant sealed in the third refrigerant circuit 20 may be, in consideration of safety, R290, NH ３ A flammable refrigerant such as olefin may be enclosed.

[0059] The amount of refrigerant circulating through the first refrigerant circuit 10 is greater than the amount of refrigerant circulating through the third refrigerant circuit 20. The amount of refrigerant charged in the third refrigerant circuit 20 is, for example, less than 1 kg, which is the standard for using a flammable refrigerant indoors. In order to improve operating efficiency, the air conditioning apparatus 100 has the amount of refrigerant circulating through the first refrigerant circuit 10 greater than the amount of refrigerant circulating through the third refrigerant circuit 20.

[0060] The second relay unit 2 has a plurality of flow path switching valves 8 that switch the supply of the heat transfer medium to the plurality of load devices 3. The second relay unit 2 has a plurality of flow path switching valves 8 in the branching section 202. The plurality of flow path switching valves 8 are respectively provided in the second relay unit 2 at an outflow side portion of the heat transfer medium flowing from the second relay unit 2 to the load devices 3 and at an inflow side portion of the heat transfer medium flowing from the load devices 3 to the second relay unit 2. The flow path switching valves 8 of the second relay unit 2 are configured, for example, as a three-way valve, and their opening and closing are controlled by the control device 6. In the air conditioning apparatus 100, the flow path of the heat transfer medium flowing in and out of the second relay unit 2 is controlled by controlling the opening and closing of the flow path switching valves 8 provided in the second relay unit 2.

[0061] In the second relay unit 2, the multiple flow path switching valves 8 are configured by six valves: flow path switching valve 8g, flow path switching valve 8h, flow path switching valve 8i, flow path switching valve 8j, flow path switching valve 8k, and flow path switching valve 8l, but the number of flow path switching valves 8 is not limited to six. The number of flow path switching valves 8 in the second relay unit 2 may be less than six or more than six depending on the number of load devices 3 connected to the second relay unit 2.

[0062] The flow path switching valves 8g, 8h, and 8i of the second relay unit 2 are arranged downstream of a third pump 26, which will be described later. The flow path switching valves 8g, 8h, and 8i are arranged downstream of the fifth intermediate heat exchanger 22 in the flow path of the heat transfer medium caused by the third pump 26. The flow path switching valves 8g, 8h, and 8i are arranged in parallel in the flow path through which the heat transfer medium caused by the third pump 26 flows.

[0063] The flow path switching valves 8g, 8h, and 8i of the second relay unit 2 are arranged downstream of any one of the flow path switching valves 8a, 8b, and 8c of the first relay unit 4 in the flow of the heat transfer medium caused by the first pump 17. Alternatively, the flow path switching valves 8g, 8h, and 8i of the second relay unit 2 are arranged downstream of any one of the flow path switching valves 8a, 8b, and 8c of the first relay unit 4 in the flow of the heat transfer medium caused by the second pump 46. The flow path switching valves 8g, 8h, and 8i are arranged in parallel in the flow path through which the heat transfer medium caused by the first pump 17 or the second pump 46 flows.

[0064] The upstream portions of the flow path switching valves 8g, 8h, and 8i of the second relay unit 2 are connected to the outlet portion of the flow path switching valve 8 of the first relay unit 4 and the outlet portion of the fifth intermediate heat exchanger 22 by the connecting pipe 70 and the internal flow path of the second relay unit 2. The upstream portions of the flow path switching valves 8g, 8h, and 8i of the second relay unit 2 are connected to the first intermediate heat exchanger 11 via the flow path switching valve 8 of the first relay unit 4 by the connecting pipe 70 and the internal flow path of the second relay unit 2.

[0065] The flow path switching valve 8j, the flow path switching valve 8k, and the flow path switching valve 8l of the second relay unit 2 are arranged upstream of the third pump 26 with respect to the third pump 26. The flow path switching valve 8j, the flow path switching valve 8k, and the flow path switching valve 8l of the second relay unit 2 are arranged upstream of the fifth intermediate heat exchanger 22 in the flow path of the heat transfer medium caused by the third pump 26. The flow path switching valve 8j, the flow path switching valve 8k, and the flow path switching valve 8l are arranged in parallel in the flow path through which the heat transfer medium caused by the third pump 26 flows.

[0066] The flow path switching valve 8j, the flow path switching valve 8k, and the flow path switching valve 8l of the second relay unit 2 are arranged upstream of the fourth intermediate heat exchanger 21 in the flow of the heat transfer medium caused by the first pump 17. Alternatively, the flow path switching valve 8j, the flow path switching valve 8k, and the flow path switching valve 8l of the second relay unit 2 are arranged upstream of the fourth intermediate heat exchanger 21 in the flow of the heat transfer medium caused by the second pump 46. The flow path switching valve 8j, the flow path switching valve 8k, and the flow path switching valve 8l are arranged in parallel in the flow path through which the heat transfer medium caused by the first pump 17 or the second pump 46 flows.

[0067] The flow path switching valves 8j, 8k and 8l of the second relay unit 2 are connected at their downstream portions to the inlet side of the fifth intermediate heat exchanger 22 and the inlet side of the fourth intermediate heat exchanger 21 by the connecting piping 70 and the internal flow paths of the second relay unit 2.

[0068] Of the flow path switching valves 8g, 8h, and 8i of the second relay unit 2, at least two flow path switching valves 8 are connected to the load-side heat exchanger 30 of the load device 3. Of the flow path switching valves 8g, 8h, and 8i of the second relay unit 2, at least one flow path switching valve 8 is arranged upstream of the load-side heat exchanger 30 in the flow of the heat transfer medium caused by the first pump 17, the second pump 46, or the third pump 26. In the flow of the heat transfer medium caused by the first pump 17, the second pump 46, or the third pump 26, a downstream portion of at least one flow path switching valve 8 is connected to an upstream portion of the load-side heat exchanger 30.

[0069] Of the flow path switching valves 8j, 8k, and 8l of the second relay unit 2, at least two flow path switching valves 8 are connected to the load-side heat exchanger 30 of the load device 3. Of the flow path switching valves 8j, 8k, and 8l of the second relay unit 2, at least one flow path switching valve 8 is arranged downstream of the load-side heat exchanger 30 in the flow of the heat transfer medium caused by the first pump 17, the second pump 46, or the third pump 26. In the flow of the heat transfer medium caused by the first pump 17, the second pump 46, or the third pump 26, an upstream portion of at least one flow path switching valve 8 is connected to a downstream portion of the load-side heat exchanger 30.

[0070] [Load Device 3] The air conditioning apparatus 100 has a plurality of load devices 3 connected to a plurality of second 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 Figures 1 and 2, the air conditioning apparatus 100 has two load devices 3, load device 3A and load device 3B, connected to the second relay unit 2, but the number of load devices 3 connected to the second relay unit 2 may be three or more.

[0071] 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.

[0072] 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.

[0073] [Connection piping 70] The air conditioning apparatus 100 includes a plurality of connection piping 70 that connect at least one heat source unit 1, at least one first relay unit 4, a plurality of second relay units 2, and a plurality of load devices 3. The connection piping 70 connects the heat source unit 1 and the first relay unit 4. The connection piping 70 connects the first relay unit 4 and the second relay unit 2. The connection piping 70 connects the second relay unit 2 and the load device 3. In other words, the connection piping 70 connects the heat source unit 1 and the load device 3 via the first relay unit 4 and the second relay unit 2. A heat transfer medium flows inside the connection piping 70.

[0074] In the air conditioning apparatus 100, the heat source unit 1 and the first relay unit 4 are connected by two connection pipes 70, and the second relay unit 2 and each of the plurality of load devices 3 are connected by two connection pipes 70. In addition, in the air conditioning apparatus 100, the first relay unit 4 and each of the plurality of second relay units 2 are connected by two connection pipes 70.

[0075] [Control device 6] The control device 6 controls the overall operation of the air conditioning apparatus 100. The control device 6 controls at least one heat source unit 1, at least one first relay unit 4, multiple second relay units 2, and multiple load devices 3. Specifically, the control device 6 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 6 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.

[0076] [Example of a heat transfer medium circuit 71 of the air conditioning apparatus 100] Fig. 3 is a circuit diagram showing an example of a first heat medium circuit 75 in the air conditioning apparatus 100 according to embodiment 1. Fig. 4 is a circuit diagram showing an example of a second heat medium circuit 76 in the air conditioning apparatus 100 according to embodiment 1. Fig. 5 is a circuit diagram showing an example of a third heat medium circuit 77 in the air conditioning apparatus 100 according to embodiment 1.

[0077] 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 in 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 in which the heat transfer medium circulates from the first relay unit 4 to the load device 3, which is an indoor unit. The third heat medium circuit 77 constitutes a circuit in which the heat transfer medium circulates from the second relay unit 2 to the load device 3, which is an indoor unit. 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.

[0078] The first heat medium circuit 75 is indicated by thick solid lines in Figures 3 to 5. As shown in Figures 3 to 5, the first heat medium circuit 75 connects at least one heat source unit 1, at least one first relay unit 4, at least one of the multiple second relay units 2, and at least one of the multiple load devices 3 via multiple connection pipes 70. The air conditioning apparatus 100 is configured so that a heat transfer medium circulates through the first heat medium circuit 75.

[0079] More specifically, the first heat medium circuit 75 is configured such that a first intermediate heat exchanger 11, at least one second intermediate heat exchanger 41, at least one fourth intermediate heat exchanger 21, and at least one of the load side heat exchangers 30 of the multiple load devices 3 are connected by multiple connection pipes 70.

[0080] In the air conditioning apparatus 100, the first intermediate heat exchanger 11, the second intermediate heat exchanger 41, the fourth intermediate heat exchanger 21, and the load-side heat exchanger 30 are connected by connecting piping 70 to form a first heat medium circuit 75 through which a heat transfer medium circulates. Note that in FIGS. 3 to 5 , the first heat medium circuit 75 is formed by the heat source unit 1, the first relay unit 4, the second relay unit 2A, and the load device 3B, but this configuration is not limited to this. The first heat medium circuit 75 may use the second relay unit 2B and the second relay unit 2C instead of the second relay unit 2A, or together with the second relay unit 2A. Furthermore, the first heat medium circuit 75 may use the load device 3A instead of the load device 3B, or together with the load device 3B.

[0081] The second heat medium circuit 76 is indicated by thick solid lines in Figures 4 and 5. As shown in Figures 4 and 5, the second heat medium circuit 76 connects at least one first relay unit 4, at least one of the multiple second relay units 2, and at least one of the multiple load devices 3 via multiple connection pipes 70. The air conditioning apparatus 100 is configured so that a heat transfer medium circulates through the second heat medium circuit 76.

[0082] More specifically, the second heat medium circuit 76 is connected to at least one third intermediate heat exchanger 42, at least one fourth intermediate heat exchanger 21, and at least one of the load side heat exchangers 30 of the multiple load devices 3 by multiple connecting pipes 70.

[0083] In the air conditioning apparatus 100, the third intermediate heat exchanger 42, the fourth intermediate heat exchanger 21, and the load-side heat exchanger 30 are connected by a connection pipe 70 to form a second heat medium circuit 76 through which a heat transfer medium circulates. Note that in FIGS. 4 and 5 , the second heat medium circuit 76 is formed by the first relay unit 4, the second relay unit 2B, and the load device 3B, but this configuration is not limited to this. The second heat medium circuit 76 may use the second relay unit 2A or the second relay unit 2C instead of the second relay unit 2B, or together with the second relay unit 2B. Furthermore, the second heat medium circuit 76 may use the load device 3A instead of the load device 3B.

[0084] The third heat medium circuit 77 is indicated by a thick solid line in Fig. 5. As shown in Fig. 5, the third heat medium circuit 77 connects at least one of the multiple second relay units 2 and at least one of the multiple load devices 3 via multiple connection pipes 70. The air conditioning apparatus 100 is configured so that a heat transfer medium circulates through the third heat medium circuit 77.

[0085] More specifically, in the third heat medium circuit 77, at least one fifth intermediate heat exchanger 22 and at least one of the load side heat exchangers 30 of the multiple load devices 3 are connected by multiple connection pipes 70.

[0086] In the air conditioning apparatus 100, the fifth intermediate heat exchanger 22 and the load-side heat exchanger 30 are connected by a connection pipe 70 to form a third heat medium circuit 77 through which a heat transfer medium circulates. Note that in FIG. 5 , the third heat medium circuit 77 is formed by the second relay unit 2C and the load device 3A, but this configuration is not limited to this. The third heat medium circuit 77 may use the second relay unit 2A or the second relay unit 2B instead of the second relay unit 2C, or together with the second relay unit 2C. Furthermore, the third heat medium circuit 77 may use the load device 3B instead of the load device 3A.

[0087] The plurality of flow path switching valves 8 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 flow path switching valves 8 are used to switch the flow path of the heat transfer medium circuit 71.

[0088] In the first embodiment, each of the first relay unit 4 and the second relay unit 2 has a plurality of flow path switching valves 8. The first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77 are provided with a plurality of flow path switching valves 8 that switch the flow path of the heat transfer medium flowing into the plurality of load devices 3 to the first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77.

[0089] The first heat medium circuit 75 is provided with a first pump 17 that circulates the heat transfer medium. The first pump 17 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 17 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 17 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the first pump 17 by arbitrarily changing the drive frequency based on instructions from the control device 6.

[0090] 2, the first pump 17 is provided in the heat source unit 1, but the installation location of the first pump 17 is not limited to the heat source unit 1. The first pump 17 may be provided, for example, in the first relay unit 4 or in the second relay unit 2. Furthermore, the first pump 17 may be provided in each of the heat source unit 1, the first relay unit 4, and the second relay unit 2.

[0091] The second heat medium circuit 76 is provided with a second pump 46 that circulates the heat transfer medium. The second pump 46 is one of the devices that make up the second heat medium circuit 76, and is provided in the first relay unit 4, for example. The second pump 46 draws 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 46 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the second pump 46 by arbitrarily changing the drive frequency based on instructions from the control device 6.

[0092] The second pump 46 has a smaller flow rate or head than the first pump 17. The second heat medium circuit 76 connects the first relay unit 4, the second 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 46 smaller than the first pump 17 reduces costs and the burden of installation work. The second pump 46 may have the same flow rate or head as the first pump 17.

[0093] 2, the second pump 46 is provided in the first relay unit 4, but the installation location of the second pump 46 is not limited to the first relay unit 4. The second pump 46 may be provided in, for example, the second relay unit 2. Furthermore, the second pump 46 may be provided in both the first relay unit 4 and the second relay unit 2.

[0094] The third heat medium circuit 77 is provided with a third pump 26 that circulates the heat transfer medium. The third pump 26 is one of the devices that make up the third heat medium circuit 77 and is provided in the second relay unit 2. The third pump 26 sucks the heat transfer medium in the third heat medium circuit 77, applies pressure to it, and sends it out to circulate. The capacity of the third pump 26 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the third pump 26 by arbitrarily changing the drive frequency based on instructions from the control device 6.

[0095] The third pump 26 has a smaller flow rate or head than the first pump 17 and the second pump 46. The third heat medium circuit 77 connects the second relay unit 2 and the load device 3, and the flow path length of the heat transfer medium circuit 71 is shorter than the first heat medium circuit 75 and the second heat medium circuit 76, so the pressure loss is not as large. Making the third pump 26 smaller than the first pump 17 and the second pump 46 reduces costs and the burden of installation work. In other words, the pumps are configured so that the flow rate or head is large for the first pump 17, medium for the second pump 46, and small for the third pump 26, for example.

[0096] 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 The third pump 26 may have the same flow rate or head as the first pump 17 and the second pump 46.

[0097] Here, we consider the product of the flow rate of the heat transfer medium and the pressure loss of the heat transfer medium in each of the first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77 in the air conditioning apparatus 100. The air conditioning apparatus 100 is preferably configured so that the product of the flow rate of the heat transfer medium and the pressure loss of the heat transfer medium in each heat medium circuit satisfies the order of the first heat medium circuit 75 ≧ the second heat medium circuit 76 ≧ the third heat medium circuit 77.

[0098] 5 , in the air conditioning apparatus 100, for example, in the first relay unit 4, heat exchange occurs between the heat transfer medium flowing through the second intermediate heat exchanger 41 and the refrigerant in the second refrigerant circuit 40, and heat exchange occurs between the heat transfer medium flowing through the third intermediate heat exchanger 42 and the refrigerant in the second refrigerant circuit 40. In the first relay unit 4, the heat transfer medium flowing through the second intermediate heat exchanger 41 generates, in the third intermediate heat exchanger 42, a heat transfer medium having a temperature range different from that of the heat transfer medium flowing through the second intermediate heat exchanger 41, via the refrigerant flowing through the second refrigerant circuit 40.

[0099] In the air conditioning apparatus 100, the second refrigerant circuit 40 of the first relay unit 4 removes heat from the first heat transfer medium flowing through one of the two connection pipes 70 connecting the heat source unit 1 and the first relay unit 4. The second refrigerant circuit 40 of the first relay unit 4 provides heat to the second heat transfer medium flowing through one of the two connection pipes 70 connecting the first relay unit 4 and the second relay unit 2, and provides heat to the second heat transfer medium flowing in at least one fourth intermediate heat exchanger 21 of the multiple second relay units 2.

[0100] Alternatively, in the air conditioning apparatus 100, the second refrigerant circuit 40 of the first relay unit 4 provides heat to a first heat transfer medium flowing through one of two connection pipes 70 connecting the heat source unit 1 and the first relay unit 4. The second refrigerant circuit 40 of the first relay unit 4 removes heat from a second heat transfer medium flowing through one of two connection pipes 70 connecting the first relay unit 4 and the second relay unit 2, and removes heat from the second heat transfer medium flowing in at least one fourth intermediate heat exchanger 21 of the multiple second relay units 2.

[0101] In the air conditioning apparatus 100, the second refrigerant circuit 40 of the first relay unit 4 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, and the second heat transfer medium is the heat transfer medium that flows through the second heat medium circuit 76.

[0102] 5 , in the air conditioning apparatus 100, for example, in the second relay unit 2, heat exchange occurs between the heat transfer medium flowing in the fourth intermediate heat exchanger 21 and the refrigerant in the third refrigerant circuit 20, and heat exchange occurs between the heat transfer medium flowing in the fifth intermediate heat exchanger 22 and the refrigerant in the third refrigerant circuit 20. In the second relay unit 2, the heat transfer medium flowing in the fourth intermediate heat exchanger 21, via the refrigerant flowing in the third refrigerant circuit 20, generates in the fifth intermediate heat exchanger 22 a heat transfer medium having a temperature range different from that of the heat transfer medium flowing in the fourth intermediate heat exchanger 21.

[0103] In the air conditioning apparatus 100, the third refrigerant circuit 20 of the second relay unit 2 removes heat from a third heat transfer medium flowing through one of two connection pipes 70 connecting the first relay unit 4 and the second relay unit 2. The third refrigerant circuit 20 of the second relay unit 2 then provides heat to a fourth heat transfer medium flowing through one of two connection pipes 70 connecting the second relay unit 2 and the load devices 3, and provides heat to the fourth heat transfer medium flowing in at least one load-side heat exchanger 30 of the multiple load devices 3.

[0104] Alternatively, in the air conditioning apparatus 100, the third refrigerant circuit 20 of the second relay unit 2 provides heat to a third heat transfer medium flowing through one of two connection pipes 70 connecting the first relay unit 4 and the second relay unit 2. The third refrigerant circuit 20 of the second relay unit 2 removes heat from a fourth heat transfer medium flowing through one of two connection pipes 70 connecting the second relay unit 2 and the load devices 3, and removes heat from the fourth heat transfer medium flowing through at least one load-side heat exchanger 30 of the multiple load devices 3.

[0105] In the air conditioning apparatus 100, the third refrigerant circuit 20 of the second relay unit 2 changes the temperatures of the third heat transfer medium and the fourth heat transfer medium. The third heat transfer medium is the heat transfer medium that flows through the first heat medium circuit 75 or the second heat medium circuit 76, and the fourth heat transfer medium is the heat transfer medium that flows through the third heat medium circuit 77.

[0106] FIG. 6 is a circuit diagram showing an example of the air conditioning apparatus 100 according to Embodiment 1. Next, the operating behavior of the air conditioning apparatus 100 during various operations will be described using FIG. 6. The operating behavior of the air conditioning apparatus 100 includes four operating modes: a cooling operation mode, a heating operation mode, a cooling-dominated operation mode, and a heating-dominated operation mode. The operations of the heat source unit 1, the first relay unit 4, the second relay unit 2, and the load device 3 include a cooling operation mode, a heating operation mode, and an operation-stop mode, respectively. Note that the flow of the heat transfer medium in the various operating modes in the following description is an example.

[0107] 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.

[0108] 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 first relay unit 4 is lower than the temperature of the intake air of the load devices 3 serving as indoor units, and one or more load devices 3 are present in heating operation. 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.

[0109] 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 first relay unit 4 is higher than the temperature of the air suctioned by the load devices 3 that are indoor units, and there are one or more load devices 3 performing cooling operation.

[0110] The operation mode of the air conditioning apparatus 100 is switched automatically by the control device 6 or by human operation. In the case of automatic operation by the control device 6, for example, the control device 6 sets the operation mode by looking at 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 6 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.

[0111] The control device 6 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's heat load. The control device 6 also controls all operation modes of at least one first relay unit 4 to be the operation mode with the smaller heat load of the overall system's heat load. For example, the control device 6 controls the supply water temperature of the heat source unit 1, which is an outdoor unit, to be the water temperature on the main operating side of the overall system, and controls the supply water temperature of the first relay unit 4 to be the water temperature on the side that is not the main operating side of the overall system.

[0112] 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. That is, 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 first relay unit 4 operates in an operation mode that results in a smaller thermal load on the entire system of the air conditioning apparatus 100. That is, 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. The operation mode of the second relay unit 2 operates in an operation mode that results in a smaller thermal load on the second relay unit 2. That is, the operation mode of the third heat medium circuit 77 operates in an operation mode that results in a smaller thermal load on the second relay unit 2.

[0113] 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.

[0114] 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 of 10°C or less. As an example, the low-temperature heat transfer medium is a heat transfer medium of 7°C as shown in FIG. 2. The low-temperature heat transfer medium generated in the heat source unit 1 is sent to the first relay unit 4 by the first pump 17. In the cooling operation mode of the heat source unit 1, the heat source-side heat exchanger 14 functions as a condenser, and the first intermediate heat exchanger 11 functions as an evaporator.

[0115] 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 of 40°C or higher. As an example, the high-temperature heat transfer medium is a heat transfer medium of 45°C. The high-temperature heat transfer medium generated in the heat source unit 1 is sent to the first relay unit 4 by the first pump 17. In the heating operation mode of the heat source unit 1, the heat source-side heat exchanger 14 functions as an evaporator, and the first intermediate heat exchanger 11 functions as a condenser.

[0116] In the cooling operation mode of the first relay unit 4, the first relay unit 4 is in an operation mode in which it generates a low-temperature heat transfer medium. The low-temperature heat transfer medium is, for example, a heat transfer medium of 10°C or less. As an example, the low-temperature heat transfer medium is a heat transfer medium of 7°C. The low-temperature heat transfer medium generated in the first relay unit 4 is sent by the second pump 46 to one or more of the plurality of second relay units 2. In the cooling operation mode of the first relay unit 4, the second intermediate heat exchanger 41 functions as a condenser, and the third intermediate heat exchanger 42 functions as an evaporator.

[0117] In the heating operation mode of the first relay unit 4, the first relay unit 4 generates a high-temperature heat transfer medium. The high-temperature heat transfer medium is, for example, a heat transfer medium of 40°C or higher. As an example, the high-temperature heat transfer medium is a heat transfer medium of 45°C. The high-temperature heat transfer medium generated in the first relay unit 4 is sent to one or more of the multiple second relay units 2 by the second pump 46. In the heating operation mode of the first relay unit 4, the second intermediate heat exchanger 41 functions as an evaporator, and the third intermediate heat exchanger 42 functions as a condenser.

[0118] In the operation stop mode of the first relay unit 4, the operation of the second compressor 43 is stopped, and the operation of the second refrigerant circuit 40 is stopped.

[0119] In the cooling operation mode of the second relay unit 2, the second relay unit 2 is in an operation mode in which it generates a low-temperature heat transfer medium. The low-temperature heat transfer medium is, for example, a heat transfer medium of 10°C or less. As an example, the low-temperature heat transfer medium is a heat transfer medium of 7°C. The low-temperature heat transfer medium generated in the second relay unit 2 is sent to the load device 3 by the third pump 26. In the cooling operation mode of the second relay unit 2, the fourth intermediate heat exchanger 21 functions as a condenser, and the fifth intermediate heat exchanger 22 functions as an evaporator.

[0120] In the heating operation mode of the second relay unit 2, the second relay unit 2 generates a high-temperature heat transfer medium. The high-temperature heat transfer medium is, for example, a heat transfer medium of 40°C or higher. As an example, the high-temperature heat transfer medium is a heat transfer medium of 45°C. The high-temperature heat transfer medium generated in the second relay unit 2 is sent to the load device 3 by the third pump 26. In the heating operation mode of the second relay unit 2, the fourth intermediate heat exchanger 21 functions as an evaporator, and the fifth intermediate heat exchanger 22 functions as a condenser.

[0121] In the operation stop mode of the second relay unit 2, the operation of the third compressor 23 is stopped, and the operation of the third refrigerant circuit 20 is stopped.

[0122] In the cooling operation mode of the load device 3, the load-side heat exchanger 30 functions as an evaporator, and heat exchange between the heat transfer medium and air is carried out in the load-side heat exchanger 30, thereby supplying cool air to the indoor space. In the heating operation mode of the load device 3, the load-side heat exchanger 30 functions as a condenser, and heat exchange between the heat transfer medium and air is carried out in the load-side heat exchanger 30, thereby supplying warm air to the indoor space.

[0123] 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.

[0124] The air conditioning device 100 is installed with a first relay unit 4 that controls the second relay unit 2, and sends a low-temperature heat transfer medium or a high-temperature heat transfer medium from the heat source unit 1 to the load device 3 via the first relay unit 4 and the second relay unit 2 depending on the thermal load of the second relay unit 2 (the total value of the cooling load and the heating load).

[0125] (Cooling operation mode) Fig. 7 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. 7. Fig. 7 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 temperature of the heat transfer medium shown in Fig. 7 is an example and is not limited to the temperature shown.

[0126] 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 first relay unit 4 and the second relay unit 2 are placed 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 40 and the third refrigerant circuit 20 and operates the first refrigerant circuit 10 and the first heat medium circuit 75.

[0127] When cooling is performed by the load device 3, the air conditioning apparatus 100 according to Embodiment 1 opens flow path switching valve 8a, flow path switching valve 8b, flow path switching valve 8c, flow path switching valve 8d, flow path switching valve 8e, and flow path switching valve 8f of the first relay unit 4 to connect the heat source unit 1 and the second relay unit 2. Furthermore, when cooling is performed by the load device 3, the air conditioning apparatus 100 according to Embodiment 1 opens flow path switching valve 8g, flow path switching valve 8j, flow path switching valve 8i, flow path switching valve 8l, etc. of the second relay unit 2 to connect the first relay unit 4 and the load device 3. Note that the air conditioning apparatus 100 adjusts the number of times that flow path switching valve 8 is opened or closed depending on the magnitude of the heat load of the second relay unit 2 and the load device 3.

[0128] 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 13 and flows to the heat source side heat exchanger 14, where it exchanges heat with air and condenses and liquefies. The condensed and liquefied refrigerant is decompressed in the first expansion mechanism 15 to become a low-pressure gas-liquid two-phase refrigerant, flows to the first intermediate heat exchanger 11, and exchanges heat with the heat transfer medium flowing in the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75 to evaporate and gasify. The gasified refrigerant passes through the first flow switching device 13 and is drawn into the first compressor 12 via an accumulator (not shown).

[0129] The heat transfer medium flowing through the first heat medium circuit 75 is cooled by the refrigerant flowing through the first intermediate heat exchanger 11 to become a low-temperature heat transfer medium, and then passes through the first relay unit 4 and the second 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 flows again into the first intermediate heat exchanger 11 of the heat source device 1 via the second relay unit 2 and the first relay unit 4.

[0130] (Heating operation mode) Fig. 8 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. 8. Fig. 8 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 temperature of the heat transfer medium shown in Fig. 8 is an example and is not limited to the temperature shown.

[0131] 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 first relay unit 4 and the second relay unit 2 are placed in the operation stop mode. That is, when the load device 3 is operated in heating mode, the air conditioning apparatus 100 according to Embodiment 1 stops the second refrigerant circuit 40 and the third refrigerant circuit 20 and operates the first refrigerant circuit 10 and the first heat medium circuit 75.

[0132] When heating is performed by the load device 3, the air conditioning apparatus 100 according to Embodiment 1 opens flow path switching valves 8a, 8b, 8c, 8d, 8e, and 8f of the first relay unit 4 to connect the heat source unit 1 and the second relay unit 2. Furthermore, when heating is performed by the load device 3, the air conditioning apparatus 100 according to Embodiment 1 opens flow path switching valves 8g and 8j or flow path switching valves 8i and 8l of the second relay unit 2 to connect the first relay unit 4 and the load device 3. The air conditioning apparatus 100 adjusts the number of times that flow path switching valve 8 is opened or closed depending on the magnitude of the heat load of the second relay unit 2 and the load device 3.

[0133] 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 13 and flows into the first intermediate heat exchanger 11. The refrigerant that flows into the first intermediate heat exchanger 11 exchanges heat with the heat transfer medium flowing through the first heat medium circuit 75 and condenses and liquefies. The condensed and liquefied refrigerant is reduced in pressure by the first expansion mechanism 15 to become a low-pressure gas-liquid two-phase refrigerant and flows into the heat source-side heat exchanger 14. The gas-liquid two-phase refrigerant that flows into the heat source-side heat exchanger 14 exchanges heat with air and evaporates into gas. The gasified refrigerant passes through the first flow switching device 13 and is drawn into the first compressor 12 via an accumulator (not shown).

[0134] The heat transfer medium flowing through the first heat medium circuit 75 is heated by the refrigerant flowing through the first intermediate heat exchanger 11 to become a high-temperature heat transfer medium, and then passes through the first relay unit 4 and the second 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 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 again into the first intermediate heat exchanger 11 of the heat source device 1 via the second relay unit 2 and the first relay unit 4.

[0135] (Cooling-dominated operation mode) FIG. 9 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. 9 . FIG. 9 is a circuit diagram showing the flow of the heat transfer medium when cooling and heating are performed by the load device 3. Note that the temperature of the heat transfer medium shown in FIG. 9 is an example and is not limited to the temperature shown. In FIG. 9 , the second relay unit 2A corresponds to the cooling operation mode of the load device 3, the second relay unit 2B corresponds to the heating operation mode of the load device 3, and the second relay unit 2C corresponds to the cooling-dominated operation mode of the load device 3.

[0136] When the air conditioning apparatus 100 according to Embodiment 1 operates in the cooling-dominated operation mode, the heat source unit 1 operates in the cooling operation mode, and the first relay unit 4 operates in the heating operation mode. Furthermore, when the air conditioning apparatus 100 according to Embodiment 1 operates in the cooling-dominated operation mode, the second relay unit 2 operates in the heating operation mode or enters the operation stop mode.

[0137] In the air conditioning apparatus 100, in the cooling-dominated operation mode, the operation mode differs between the heat source unit 1 and the at least one first relay unit 4. In the air conditioning apparatus 100, the temperature of the heat transfer medium sent from the heat source unit 1 to the at least one first relay unit 4 differs from the temperature of the heat transfer medium sent from the at least one first relay unit 4 to one or more of the multiple second relay units 2.

[0138] 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 at least one first relay unit 4 is chilled water, the heat transfer medium sent from the at least one first relay unit 4 to one or more of the multiple second relay units 2 is hot water. The heat transfer medium sent from the heat source unit 1 to at least one first relay unit 4 here is the heat transfer medium cooled by the first refrigerant circuit 10. Furthermore, the heat transfer medium sent from the first relay unit 4 to one or more of the multiple second relay units 2 here is the heat transfer medium heated by the second refrigerant circuit 40.

[0139] 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 40, and the first heat medium circuit 75. In the cooling-dominated operation mode, the air conditioning apparatus 100 according to Embodiment 1 operates or stops the third refrigerant circuit 20, and operates one or more of the second heat medium circuit 76 and the third heat medium circuit 77.

[0140] The air conditioning apparatus 100 according to Embodiment 1, for example, in the first heat medium circuit 75, opens the flow path switching valves 8a and 8b of the first relay unit 4 and the flow path switching valves 8c and 8f of the first relay unit 4 so as to connect the heat source unit 1 and the second relay unit 2. Furthermore, for example, in the second heat medium circuit 76, the air conditioning apparatus 100 opens the flow path switching valves 8b and 8e of the first relay unit 4 so as to connect the first relay unit 4 and the second relay unit 2.

[0141] The air conditioning apparatus 100 according to the first embodiment opens the flow path switching valves 8i and 8l of the second relay units 2A, 2B, and 2C in the first heat medium circuit 75 and the second heat medium circuit 76, for example, to connect the first relay unit 4 and the load device 3. Furthermore, the air conditioning apparatus 100 according to the first embodiment opens the flow path switching valves 8g and 8j of the second relay unit 2C in the third heat medium circuit 77, for example, to connect the second relay unit 2 and the load device 3. The air conditioning apparatus 100 adjusts the number of times the flow path switching valves 8 are opened and closed depending on the magnitude of the heat load of the second relay unit 2 and the load device 3.

[0142] 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 13 and flows to the heat source side heat exchanger 14, where it exchanges heat with air and condenses and liquefies. The condensed and liquefied refrigerant is decompressed in the first expansion mechanism 15 to become a low-pressure gas-liquid two-phase refrigerant, flows to the first intermediate heat exchanger 11, and exchanges heat with the heat transfer medium flowing in the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75 to evaporate and gasify. The gasified refrigerant passes through the first flow switching device 13 and is drawn into the first compressor 12 via an accumulator (not shown).

[0143] The heat transfer medium flowing through the first heat medium circuit 75 is cooled by the refrigerant flowing through the first intermediate heat exchanger 11 to become a low-temperature heat transfer medium, and then passes through the first relay unit 4 and the second relay unit 2A and flows into the load-side heat exchanger 30 of the load device 3B. The heat transfer medium flowing through the first heat medium circuit 75 is cooled by the refrigerant flowing through the first intermediate heat exchanger 11 to become a low-temperature heat transfer medium, and then passes through the first relay unit 4 and the second relay unit 2C and flows into the load-side heat exchanger 30 of the load device 3B.

[0144] The heat transfer medium that has flowed 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 has flowed out of the load device 3B passes through the second relay unit 2A and the first relay unit 4, and the second relay unit 2C and the first relay unit 4, and flows again into the first intermediate heat exchanger 11 of the heat source unit 1.

[0145] In the second refrigerant circuit 40 of the first relay unit 4, high-temperature, high-pressure gas refrigerant discharged from the second compressor 43 passes through the second flow switching device 44 and flows into the third intermediate heat exchanger 42. The refrigerant that flows into the third intermediate heat exchanger 42 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 decompressed by the second expansion mechanism 45 to become a low-pressure gas-liquid two-phase refrigerant and flows into the second intermediate heat exchanger 41. The gas-liquid two-phase refrigerant that flows into the second intermediate heat exchanger 41 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 44 and is drawn into the second compressor 43 via an accumulator (not shown).

[0146] The heat transfer medium flowing through the second heat medium circuit 76 is heated by the refrigerant flowing through the third intermediate heat exchanger 42 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 second relay unit 2B. The heat transfer medium that flows into the load-side heat exchanger 30 of the load device 3B is cooled by heat exchange with the indoor air and flows out of the load device 3B. The cooled heat transfer medium that flows out of the load device 3B flows again into the third intermediate heat exchanger 42 of the first relay unit 4 via the second relay unit 2B.

[0147] In the third refrigerant circuit 20 of the second relay unit 2C, high-temperature, high-pressure gas refrigerant discharged from the third compressor 23 passes through the third flow switching device 24 and flows into the fifth intermediate heat exchanger 22. The refrigerant that flows into the fifth intermediate heat exchanger 22 exchanges heat with the heat transfer medium flowing through the third heat medium circuit 77 and condenses and liquefies. The condensed and liquefied refrigerant is decompressed by the third expansion mechanism 25 to become a low-pressure gas-liquid two-phase refrigerant and flows into the fourth intermediate heat exchanger 21. The gas-liquid two-phase refrigerant that flows into the fourth intermediate heat exchanger 21 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 third flow switching device 24 and is drawn into the third compressor 23 via an accumulator (not shown).

[0148] The heat transfer medium flowing through the third heat medium circuit 77 is heated by the refrigerant flowing through the fifth intermediate heat exchanger 22 to become a high-temperature heat transfer medium, and then flows into the load-side heat exchanger 30 of the load device 3A. The heat transfer medium that has flowed 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 has flowed out of the load device 3A flows again into the fifth intermediate heat exchanger 22 of the second relay unit 2C.

[0149] 9 , the heat transfer medium flowing through the first heat medium circuit 75, which flows out of the second relay unit 2C and heads toward the first relay unit 4, has heat removed in the fourth intermediate heat exchanger 21 due to the heating operation state mode of the third refrigerant circuit 20. The heat transfer medium that has flowed out of the load side heat exchanger 30 of the load device 3B has heat removed in the fourth intermediate heat exchanger 21 by the refrigerant flowing through the third refrigerant circuit 20, equivalent to the amount of heat generated by the heating operation of the third refrigerant circuit 20, and the temperature drops.

[0150] In the first relay unit 4, the heat transfer medium that has flowed out of the second relay unit 2A and flowed into the first relay unit 4 and the heat transfer medium that has flowed out of the second relay unit 2C and flowed into the first relay unit 4 are mixed. Heat is removed from this mixed heat transfer medium in the second intermediate heat exchanger 41 depending on the heating operation state mode of the second refrigerant circuit 40. In the second intermediate heat exchanger 41, the refrigerant flowing through the second refrigerant circuit 40 removes heat from the mixed heat transfer medium that has flowed in from the second relay unit 2A and the second relay unit 2C, equivalent to the amount of heat generated by the heating operation of the second refrigerant circuit 40, so that the temperature of the heat transfer medium decreases and the medium heads toward the heat source unit 1.

[0151] (Heating-dominated operation mode) FIG. 10 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 the heating-dominated operation mode of the air conditioning apparatus 100 will be described with reference to FIG. 10 . FIG. 10 is a circuit diagram showing the flow of the heat transfer medium when cooling and heating are performed by the load device 3. Note that the temperature of the heat transfer medium shown in FIG. 10 is an example and is not limited to the temperature shown. In FIG. 10 , the second relay unit 2A corresponds to the heating operation mode of the load device 3, the second relay unit 2B corresponds to the cooling operation mode of the load device 3, and the second relay unit 2C corresponds to the heating-dominated operation mode of the load device 3.

[0152] When the air conditioning apparatus 100 according to Embodiment 1 operates in the heating-dominated operation mode, the heat source unit 1 operates in the heating operation mode, and the first relay unit 4 operates in the cooling operation mode. Furthermore, when the air conditioning apparatus 100 according to Embodiment 1 operates in the heating-dominated operation mode, the second relay unit 2 operates in the cooling operation mode or enters the operation stop mode.

[0153] In the heating-dominant operation mode of the air conditioning apparatus 100, the operation mode is different between the heat source unit 1 and the at least one first relay unit 4. In the air conditioning apparatus 100, the temperature of the heat transfer medium sent from the heat source unit 1 to the at least one first relay unit 4 is different from the temperature of the heat transfer medium sent from the at least one first relay unit 4 to one or more of the multiple second relay units 2.

[0154] In the air conditioning apparatus 100, in the heating-dominated operation mode, when the heat transfer medium sent from the heat source unit 1 to at least one first relay unit 4 is hot water, the heat transfer medium sent from the at least one first relay unit 4 to one or more of the multiple second relay units 2 is cold water. The heat transfer medium sent from the heat source unit 1 to at least one first relay unit 4 here is the heat transfer medium heated by the first refrigerant circuit 10. Furthermore, the heat transfer medium sent from the first relay unit 4 to one or more of the multiple second relay units 2 here is the heat transfer medium cooled by the second refrigerant circuit 40.

[0155] 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 40, and the first heat medium circuit 75. In the heating-dominated operation mode, the air conditioning apparatus 100 according to Embodiment 1 operates or stops the third refrigerant circuit 20, and operates one or more of the second heat medium circuit 76 and the third heat medium circuit 77.

[0156] The air conditioning apparatus 100 according to Embodiment 1, for example, in the first heat medium circuit 75, opens the flow path switching valves 8a and 8b of the first relay unit 4 and the flow path switching valves 8c and 8f of the first relay unit 4 so as to connect the heat source unit 1 and the second relay unit 2. Furthermore, for example, in the second heat medium circuit 76, the air conditioning apparatus 100 opens the flow path switching valves 8b and 8e of the first relay unit 4 so as to connect the first relay unit 4 and the second relay unit 2.

[0157] The air conditioning apparatus 100 according to the first embodiment opens the flow path switching valves 8i and 8l of the second relay units 2A, 2B, and 2C in the first heat medium circuit 75 and the second heat medium circuit 76, for example, to connect the first relay unit 4 and the load device 3. Furthermore, the air conditioning apparatus 100 according to the first embodiment opens the flow path switching valves 8g and 8j of the second relay unit 2C in the third heat medium circuit 77, for example, to connect the second relay unit 2 and the load device 3. The air conditioning apparatus 100 adjusts the number of times the flow path switching valves 8 are opened and closed depending on the magnitude of the heat load of the second relay unit 2 and the load device 3.

[0158] 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 13 and flows into the first intermediate heat exchanger 11. The refrigerant that flows into the first intermediate heat exchanger 11 exchanges heat with the heat transfer medium flowing through the first heat medium circuit 75 and condenses and liquefies. The condensed and liquefied refrigerant is reduced in pressure by the first expansion mechanism 15 to become a low-pressure gas-liquid two-phase refrigerant and flows into the heat source-side heat exchanger 14. The gas-liquid two-phase refrigerant that flows into the heat source-side heat exchanger 14 exchanges heat with air and evaporates into gas. The gasified refrigerant passes through the first flow switching device 13 and is drawn into the first compressor 12 via an accumulator (not shown).

[0159] The heat transfer medium flowing through the first heat medium circuit 75 is heated by the refrigerant flowing through the first intermediate heat exchanger 11 to become a high-temperature heat transfer medium, and then passes through the first relay unit 4 and the second relay unit 2A and flows into the load-side heat exchanger 30 of the load device 3B. The heat transfer medium flowing through the first heat medium circuit 75 is heated by the refrigerant flowing through the first intermediate heat exchanger 11 to become a high-temperature heat transfer medium, and then passes through the first relay unit 4 and the second relay unit 2C and flows into the load-side heat exchanger 30 of the load device 3B. The heat transfer medium that has flowed into the load-side heat exchanger 30 of the load device 3B exchanges heat with indoor air to be cooled, and then flows out of the load device 3B. The cooled heat transfer medium that has flowed out of the load device 3B flows again into the first intermediate heat exchanger 11 of the heat source device 1 via the second relay unit 2A and the first relay unit 4, and the second relay unit 2C and the first relay unit 4.

[0160] In the second refrigerant circuit 40 of the first relay unit 4, high-temperature, high-pressure gas refrigerant discharged from the second compressor 43 passes through the second flow switching device 44 and flows into the second intermediate heat exchanger 41. The refrigerant that flows into the second intermediate heat exchanger 41 exchanges heat with the heat transfer medium flowing through the first heat medium circuit 75 and condenses and liquefies. The condensed and liquefied refrigerant is reduced in pressure by the second expansion mechanism 45 to become a low-pressure gas-liquid two-phase refrigerant and flows into the third intermediate heat exchanger 42. The gas-liquid two-phase refrigerant that flows into the third intermediate heat exchanger 42 exchanges heat with the heat transfer medium flowing through the second heat medium circuit 76 and evaporates into gas. The gasified refrigerant passes through the second flow switching device 44 and is drawn into the second compressor 43 via an accumulator (not shown).

[0161] The heat transfer medium flowing through the second heat medium circuit 76 is cooled by the refrigerant flowing through the third intermediate heat exchanger 42 to become a low-temperature heat transfer medium, and then passes through the second relay unit 2B and flows into the load-side heat exchanger 30 of the load device 3B. The heat transfer medium that has flowed 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 has flowed out of the load device 3B flows again into the third intermediate heat exchanger 42 of the first relay unit 4 via the second relay unit 2B.

[0162] In the third refrigerant circuit 20 of the second relay unit 2C, high-temperature, high-pressure gas refrigerant discharged from the third compressor 23 passes through the third flow switching device 24 and flows into the fourth intermediate heat exchanger 21. The refrigerant that flows into the fourth intermediate heat exchanger 21 exchanges heat with the heat transfer medium flowing through the first heat medium circuit 75 and condenses and liquefies. The condensed and liquefied refrigerant is decompressed by the third expansion mechanism 25 to become a low-pressure gas-liquid two-phase refrigerant and flows into the fifth intermediate heat exchanger 22. The gas-liquid two-phase refrigerant that flows into the fifth intermediate heat exchanger 22 exchanges heat with the heat transfer medium flowing through the third heat medium circuit 77 and evaporates into gas. The gasified refrigerant passes through the third flow switching device 24 and is drawn into the third compressor 23 via an accumulator (not shown).

[0163] The heat transfer medium flowing through the third heat medium circuit 77 is cooled by the refrigerant flowing through the fifth intermediate heat exchanger 22 to become a low-temperature heat transfer medium, and then flows into the load-side heat exchanger 30 of the load device 3A. The heat transfer medium that has flowed into the load-side heat exchanger 30 of the load device 3A is heated by heat exchange with the indoor air and flows out of the load device 3A. The heated heat transfer medium that has flowed out of the load device 3A flows again into the fifth intermediate heat exchanger 22 of the second relay unit 2C.

[0164] 10 , the heat transfer medium flowing through the first heat medium circuit 75, which flows out of the second relay unit 2C and heads toward the first relay unit 4, is given heat in the fourth intermediate heat exchanger 21 due to the cooling operation state mode of the third refrigerant circuit 20. The heat transfer medium that has flowed out of the load side heat exchanger 30 of the load device 3B is given heat in the fourth intermediate heat exchanger 21 by the refrigerant flowing through the third refrigerant circuit 20, equivalent to the amount of heat due to the cooling operation of the third refrigerant circuit 20, and the temperature rises.

[0165] In the first relay unit 4, the heat transfer medium that has flowed out of the second relay unit 2A and flowed into the first relay unit 4 and the heat transfer medium that has flowed out of the second relay unit 2C and flowed into the first relay unit 4 are mixed. This mixed heat transfer medium is imparted with heat in the second intermediate heat exchanger 41 depending on the cooling operation state mode of the second refrigerant circuit 40. In the second intermediate heat exchanger 41, the refrigerant flowing through the second refrigerant circuit 40 imparts heat equivalent to the amount of heat generated by the heating operation of the second refrigerant circuit 40 to the heat transfer medium that has flowed in from the second relay unit 2A and the second relay unit 2C and is mixed, so that the temperature of the heat transfer medium increases and the medium flows toward the heat source unit 1.

[0166] 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 tank stores water supplied via a water supply pipe (not shown). The hot water storage tank stores hot water heated by the heat source device 1, the first relay unit 4, or the second 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.

[0167] Fig. 11 is a configuration diagram that schematically shows a first modified example of the air conditioning apparatus 100 according to the first embodiment. The numbers of heat source units 1, first relay units 4, second relay units 2, and load devices 3 are not limited to those described above. As shown in Fig. 11 , two or more heat source units 1 may be installed. When multiple heat source units 1 are installed, the heat source units 1 may be connected to each other via connection pipes 70. In the air conditioning apparatus 100, multiple heat source units 1 are installed in parallel, and two connection pipes 70 connected to at least one first relay unit 4 may branch off and be connected to each of the multiple heat source units 1.

[0168] 12 is a configuration diagram that schematically shows a second modification of the air conditioning apparatus 100 according to Embodiment 1. Two or more first relay units 4 may be installed. When multiple first relay units 4 are installed, the first relay units 4 may be connected to each other via connection pipes 70. In the air conditioning apparatus 100, multiple first relay units 4 may be installed in parallel, and two connection pipes 70 connected to multiple second relay units 2 may branch off and be connected to each of the multiple first relay units 4.

[0169] The number of load devices 3 connected to each second relay unit 2 may be one, or three or more. In this case, the air conditioning apparatus 100 may configure all of the load devices 3 as indoor units, or may configure 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 or the first relay unit 4 without going through the second relay unit 2.

[0170] [Operation and Effect of Air Conditioning Apparatus 100] The air conditioning apparatus 100 includes at least one heat source unit 1, at least one first relay unit 4 connected to the at least one heat source unit 1, a plurality of second relay units 2 connected to the at least one first relay unit 4, and a plurality of load devices 3 connected to the plurality of second relay units 2. The air conditioning apparatus 100 also includes a plurality of connection pipes 70 that connect the at least one heat source unit 1, the at least one first relay unit 4, the plurality of second relay units 2, and the plurality of load devices 3. The 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 11 that exchanges heat between the refrigerant flowing through the first refrigerant circuit 10 and a heat transfer medium flowing therein, and a heat source-side heat exchanger 14 that exchanges heat between the refrigerant flowing through the first refrigerant circuit 10 and air.

[0171] At least one first relay unit 4 includes a second refrigerant circuit 40 through which a refrigerant circulates. The second refrigerant circuit 40 includes a second intermediate heat exchanger 41 through which the refrigerant flowing in the second refrigerant circuit 40 exchanges heat with a heat transfer medium flowing therethrough, and a third intermediate heat exchanger 42 through which the refrigerant flowing in the second refrigerant circuit 40 exchanges heat with the heat transfer medium flowing therethrough. The plurality of second relay units 2 include a third refrigerant circuit 20 through which a refrigerant circulates. The third refrigerant circuit 20 includes a fourth intermediate heat exchanger 21 through which the refrigerant flowing in the third refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therethrough, and a fifth intermediate heat exchanger 22 through which the refrigerant flowing in the third refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therethrough.

[0172] The air conditioning device 100 has a heat transfer medium flowing between at least one heat source unit 1, at least one first relay unit 4, at least one of the multiple second relay units 2, and at least one of the multiple load devices 3 via multiple connecting pipes 70.

[0173] Therefore, when the air conditioning apparatus 100 according to Embodiment 1 simultaneously performs cooling and heating on a plurality of load devices 3, cooling or heating can be performed by the first refrigerant circuit 10 provided in the heat source unit 1, the second refrigerant circuit 40 provided in the first relay unit 4, and the third refrigerant circuit 20 provided in the second relay unit 2. Therefore, the air conditioning apparatus 100 can reduce the number of pipes connecting the heat source unit 1 and the first relay unit 4 to two, which requires fewer pipes and reduces the burden of piping work.

[0174] 13 is a schematic diagram illustrating an air conditioning apparatus 100L according to a comparative example. The air conditioning apparatus 100L according to the comparative example is a water-based air conditioning system that is configured with a group of indoor units consisting of a heat source unit 1, a second relay unit 2, and a load unit 3, and is capable of simultaneous cooling and heating operation, and is a system in which the second relay unit 2 has a refrigeration cycle.

[0175] In the air conditioning apparatus 100L according to the comparative example, when multiple second relay units 2 are connected in parallel to the heat source unit 1, if the operation modes of the second relay units 2 are different, the temperature of the heat transfer medium supplied from the heat source unit 1 can only satisfy either the cooling system or the heating system. When the operation modes are different, this refers to when the operation modes are different for the cooling system (cooling operation state or cooling-dominated operation state) or the heating system (heating operation state or heating-dominated operation state).

[0176] For example, a case where there are three second relay units 2 in the air conditioning apparatus 100L according to the comparative example will be considered using Fig. 2. In the air conditioning apparatus 100L according to the comparative example, when there are three second relay units 2, the first relay unit 4 in Fig. 2 is not present. As shown in Fig. 2, in the air conditioning apparatus 100L, the load device 3B connected to the second relay unit 2A is in cooling operation, the load device 3B connected to the second relay unit 2B is in heating operation, and the multiple load devices 3 connected to the second relay unit 2C are in cooling-dominated operation.

[0177] In this case, the air conditioning apparatus 100L operates mainly for cooling as a whole with the multiple second relay units 2, and therefore generates a low-temperature heat transfer medium in the heat source unit 1. Note that the operation mainly for cooling here refers to an operation in which a greater amount of low-temperature heat transfer medium is supplied to the load device 3 from the multiple second relay units 2 than to the high-temperature heat transfer medium, depending on the heat load required by the load device 3.

[0178] The second relay unit 2B supplies a high-temperature heat medium to the load device 3B performing heating operation. The heat transfer medium is supplied to the load device 3B via the second relay unit 2B, but the method of generating the high-temperature heat transfer medium to be supplied to the second relay unit 2B is an issue. In the air conditioning device 100L, the multiple second relay units 2 as a whole mainly operate in cooling mode, so a low-temperature heat transfer medium is generated in the heat source unit 1. Therefore, the air conditioning device 100L according to the comparative example cannot supply a high-temperature heat transfer medium to the second relay unit 2B.

[0179] The air conditioning apparatus 100L according to the comparative example faces an issue of how to generate a high-temperature heat transfer medium required by any one of the multiple second relay units 2 when a low-temperature heat transfer medium is generated in the heat source unit 1. Alternatively, the air conditioning apparatus 100L according to the comparative example faces an issue of how to generate a low-temperature heat transfer medium required by any one of the multiple second relay units 2 when a high-temperature heat transfer medium is generated in the heat source unit 1.

[0180] The air conditioning apparatus 100 according to the first embodiment includes a first relay unit 4 having a second refrigerant circuit 40. The air conditioning apparatus 100 is provided with a first relay unit 4 that controls the second relay units 2, and the heat source unit 1 and the first relay unit 4 generate a low-temperature or high-temperature heat transfer medium to be supplied to the second relay unit 2 depending on the thermal load of the second relay unit 2 (the total value of cooling and heating).

[0181] In the air conditioning apparatus 100, when a low-temperature heat transfer medium is generated in the heat source apparatus 1, the first relay apparatus 4 can generate a high-temperature heat transfer medium required by any one of the multiple second relay apparatuses 2. Alternatively, when a high-temperature heat transfer medium is generated in the heat source apparatus 1, the first relay apparatus 4 can generate a low-temperature heat transfer medium required by any one of the multiple second relay apparatuses 2. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the second relay apparatus 2 and the load apparatus 3 are different. Furthermore, the air conditioning apparatus 100 can supply a heat transfer medium more efficiently to the thermal loads required by the multiple load apparatuses 3 and the multiple second relay apparatuses 2 compared to when the air conditioning apparatus 100 does not have a first relay apparatus 4.

[0182] The air conditioning apparatus 100 is also formed with 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 through which a heat transfer medium circulates. The air conditioning apparatus 100 is equipped with a plurality of flow path switching valves 8 that are connected to a plurality of connection pipes 70 and are used to switch the flow path of the heat transfer medium to form one or more of the first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77. By including a plurality of flow path switching valves 8, the air conditioning apparatus 100 can form one or more of the first heat medium circuit 75, the second heat medium circuit 76, and the 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 second relay unit 2 and the load device 3 are different. Furthermore, compared to when the air conditioning device 100 does not have a first relay unit 4, the air conditioning device 100 can efficiently supply heat transfer medium to the heat load required by multiple load devices 3 and multiple second relay units 2.

[0183] Furthermore, in the air conditioning apparatus 100, at least one first relay unit 4 and multiple second relay units 2 each have multiple flow path switching valves 8. By having multiple flow path switching valves 8, the air conditioning apparatus 100 can configure one or more of 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 second relay unit 2 and the load devices 3 are different. 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 second relay units 2 compared to an air conditioning apparatus 100 not having a first relay unit 4.

[0184] Furthermore, the air conditioning apparatus 100 is configured so that the product of the flow rate of the heat transfer medium and the pressure loss of the heat transfer medium in each of the first heat medium circuit 75, the second heat medium circuit 76, and the third heat medium circuit 77 is in the order of first heat medium circuit ≧ second heat medium circuit ≧ third heat medium circuit. Compared to an air conditioning apparatus 100 not having this configuration, the air conditioning apparatus 100 can supply the heat transfer medium more efficiently to the heat loads required by the multiple load devices 3 and the multiple second relay units 2.

[0185] Furthermore, in the air conditioning apparatus 100, the heat source unit 1 and the first relay unit 4 are connected by two connection pipes 70, and the second relay unit 2 and the load device 3 are connected by two connection pipes 70. In the air conditioning apparatus 100, there are two pipes connecting the heat source unit 1 and the first relay unit 4, and there are also two pipes connecting the second 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.

[0186] Furthermore, in the air conditioning apparatus 100, in the first relay unit 4, heat exchange occurs between the heat transfer medium flowing through the second intermediate heat exchanger 41 and the refrigerant in the second refrigerant circuit 40, and heat exchange occurs between the heat transfer medium flowing through the third intermediate heat exchanger 42 and the refrigerant in the second refrigerant circuit 40. In the air conditioning apparatus 100, in the first relay unit 4, the heat transfer medium flowing through the second intermediate heat exchanger 41 generates a heat transfer medium in the third intermediate heat exchanger 42, via the refrigerant flowing through the second refrigerant circuit 40, in a temperature range different from that of the heat transfer medium flowing through the second intermediate heat exchanger 41. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the second relay unit 2 and the load devices 3 are different. 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 second relay units 2, compared to an air conditioning apparatus not having this configuration.

[0187] Furthermore, in the air conditioning apparatus 100, in the second relay unit 2, heat exchange occurs between the heat transfer medium flowing through the fourth intermediate heat exchanger 21 and the refrigerant in the third refrigerant circuit 20, and heat exchange occurs between the heat transfer medium flowing through the fifth intermediate heat exchanger 22 and the refrigerant in the third refrigerant circuit 20. In the air conditioning apparatus 100, in the second relay unit 2, the heat transfer medium flowing through the fourth intermediate heat exchanger 21 generates a heat transfer medium in the fifth intermediate heat exchanger 22, via the refrigerant flowing through the third refrigerant circuit 20, having a temperature range different from that of the heat transfer medium flowing through the fourth intermediate heat exchanger 21. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the load devices 3 are different. 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, compared to an air conditioning apparatus not having this configuration.

[0188] Furthermore, the second refrigerant circuit 40 of the first relay unit 4 removes heat from the first heat transfer medium flowing through one of two connection pipes 70 connecting the heat source unit 1 and the first relay unit 4, and provides heat to the second heat transfer medium flowing in at least one fourth intermediate heat exchanger 21 of the multiple second relay units 2. Alternatively, the second refrigerant circuit 40 of the first relay unit 4 provides heat to the first heat transfer medium flowing through one of two connection pipes 70 connecting the heat source unit 1 and the first relay unit 4, and removes heat from the second heat transfer medium flowing in at least one fourth intermediate heat exchanger 21 of the multiple second relay units 2. The second refrigerant circuit 40 of the first relay unit 4 changes the temperatures of the first heat transfer medium and the second heat transfer medium due to this configuration. Therefore, the air conditioning apparatus 100 can continue cooling and heating even if the thermal loads (cooling system and heating system) of the second relay unit 2 and the load device 3 are different. 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 second relay units 2.

[0189] Furthermore, the third refrigerant circuit 20 of the second relay unit 2 removes heat from the third heat transfer medium flowing through one of the two connecting pipes 70 connecting the first relay unit 4 and the second relay unit 2, and provides heat to the fourth heat transfer medium flowing through at least one of the multiple load devices 3. Alternatively, the third refrigerant circuit 20 of the second relay unit 2 provides heat to the third heat transfer medium flowing through one of the two connecting pipes 70 connecting the first relay unit 4 and the second relay unit 2, and removes heat from the fourth heat transfer medium flowing through at least one of the multiple load devices 3. With this configuration, the third refrigerant circuit 20 of the second relay unit 2 changes the temperatures of the third heat transfer medium and the fourth heat transfer medium. Therefore, the air conditioning apparatus 100 can continue cooling and heating even if the thermal loads (cooling system and heating system) of the second relay unit 2 and the load devices 3 are different. 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 second relay units 2.

[0190] The second relay unit 2 also has multiple flow path switching valves 8 that switch the supply of heat transfer medium to the multiple load devices 3. By having multiple flow path switching valves 8, the air conditioning apparatus 100 can configure one or more of 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 load devices 3 are different. Furthermore, the air conditioning apparatus 100 can supply heat transfer medium more efficiently to the thermal loads required by the multiple load devices 3 and the multiple second relay units 2 compared to an air conditioning apparatus 100 that does not have a first relay unit 4.

[0191] Furthermore, the air conditioning apparatus 100 has different operating modes for the heat source apparatus 1 and at least one first relay apparatus 4. Due to this configuration, the air conditioning apparatus 100 has a different temperature for the heat transfer medium sent from the heat source apparatus 1 to at least one first relay apparatus 4 and the heat transfer medium sent from the at least one first relay apparatus 4 to one or more of the multiple second relay apparatuses 2. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the second relay apparatus 2 and the load apparatus 3 are different. Furthermore, the air conditioning apparatus 100 can supply the heat transfer medium more efficiently to the thermal loads required by the multiple load apparatuses 3 and the multiple second relay apparatuses 2 compared to an air conditioning apparatus 100 not having a first relay apparatus 4.

[0192] Furthermore, the air conditioning apparatus 100 has different operating modes for the heat source unit 1 and at least one first relay unit 4. Due to this configuration, when the heat transfer medium sent from the heat source unit 1 to at least one first relay unit 4 is hot water, the heat transfer medium sent from at least one first relay unit 4 to one or more of the multiple second relay units 2 is chilled water. Alternatively, due to this configuration, the air conditioning apparatus 100 has when the heat transfer medium sent from the heat source unit 1 to at least one first relay unit 4 is chilled water, the heat transfer medium sent from at least one first relay unit 4 to one or more of the multiple second relay units 2 is hot water. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the second relay unit 2 and the load device 3 are different. Furthermore, compared to when the air conditioning device 100 does not have a first relay unit 4, the air conditioning device 100 can efficiently supply heat transfer medium to the heat load required by multiple load devices 3 and multiple second relay units 2.

[0193] The air conditioning apparatus 100 also includes a control device 6 that controls at least one heat source unit 1, at least one first relay unit 4, multiple second relay units 2, and multiple load devices 3. The control device 6 controls all operation modes of the at least one heat source unit 1 so that they are in the operation mode with the larger thermal load of the overall system. The control device 6 also controls all operation modes of the at least one first relay unit 4 so that they are in the operation mode with the smaller thermal load of the overall system. Therefore, the air conditioning apparatus 100 can continue heating and cooling even if the thermal loads (cooling system and heating system) of the second relay unit 2 and the load devices 3 are different. 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 second relay units 2 compared to an air conditioning apparatus 100 that does not include a first relay unit 4.

[0194] Furthermore, the air conditioning apparatus 100 has a plurality of heat source units 1 installed in parallel, and two connection pipes 70 connected to at least one first relay unit 4 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 first relay units 4 installed in parallel, and two connection pipes 70 connected to a plurality of second relay units 2 branch off and are connected to each of the plurality of first relay units 4. 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.

[0195] Embodiment 2. Figure 14 is a schematic diagram showing the configuration of an air conditioning apparatus 100 according to embodiment 2. Next, the air conditioning apparatus 100 according to embodiment 2 will be described with reference to Figure 14. Note that the same components as those in the air conditioning apparatus 100 described in embodiment 1 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0196] The air conditioning apparatus 100 according to the second embodiment differs from the air conditioning apparatus 100 according to the first embodiment in the arrangement of the flow path switching valves 8. In the air conditioning apparatus 100 according to the second embodiment, the plurality of flow path switching valves 8 are provided in the second relay unit 2, and are also provided between the first relay unit 4 and the second relay unit 2 in the flow path of the heat transfer medium.

[0197] In the air conditioning apparatus 100 according to Embodiment 1, as shown in Fig. 2, the first relay unit 4 has a chilled / hot water generating unit 401 and a branching unit 402. In contrast, in the air conditioning apparatus 100 according to Embodiment 2, the chilled / hot water generating unit 401 and the branching unit 402 are separate. In the air conditioning apparatus 100 according to Embodiment 2, the first relay unit 4 has the chilled / hot water generating unit 401 but does not have the branching unit 402. In the air conditioning apparatus 100, the branching unit 402 is provided independently.

[0198] 14 , the air conditioning apparatus 100 according to embodiment 2 has three branch sections 402: branch section 402A, branch section 402B, and branch section 402C, but the number of branch sections 402 is not limited to three. The air conditioning apparatus 100 according to embodiment 2 has at least one branch section 402.

[0199] 14, the branching portion 402 has two flow path switching valves 8, namely, the flow path switching valve 8a and the flow path switching valve 8d, but the number of flow path switching valves 8 is not limited to two. The branching portion 402 has a plurality of flow path switching valves 8.

[0200] In the air conditioning apparatus 100 according to the second embodiment, two connection pipes 70 for cold water and two connection pipes 70 for hot water are used from the first relay unit 4 to the branching section 402. The air conditioning apparatus 100 according to the second embodiment has a flow path switching valve 8 at the branching section 402, and the flow path switching valve 8 is provided with a selection means for allowing either cold water or hot water to flow.

[0201] [Effects of the Air Conditioning Apparatus 100] The multiple flow path switching valves 8 of the air conditioning apparatus 100 are provided in the second relay unit 2 and between the first relay unit 4 and the second relay unit 2. By providing multiple flow path switching valves 8, the air conditioning apparatus 100 can configure one or more of the first heat medium circuit 75, the second heat medium circuit 76, and the 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 load devices 3 are different. Furthermore, compared to an air conditioning apparatus 100 not having a first relay unit 4, 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 the multiple second relay units 2. Furthermore, the air conditioning apparatus 100 of the second embodiment has branch units 402 provided in multiple locations in advance, which facilitates connection and installation of the second relay unit 2 and reduces the burden of piping work.

[0202] The air conditioning apparatus 100 has been described above based on the embodiment, but the air conditioning apparatus 100 is not limited to the configuration of the above-described embodiment. The above-described first and second embodiments can be implemented in combination with each other. The configuration of the air conditioning apparatus 100 described above is an example, and other components may be included, or some components may be omitted. In short, the air conditioning apparatus 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 apparatus 100.

[0203] 1 Heat source unit, 2 Second relay unit, 2A Second relay unit, 2B Second relay unit, 2C Second relay unit, 3 Load device, 3A Load device, 3B Load device, 4 First relay unit, 6 Control device, 8 Flow path switching valve, 8a Flow path switching valve, 8b Flow path switching valve, 8c Flow path switching valve, 8d Flow path switching valve, 8e Flow path switching valve, 8f Flow path switching valve, 8g Flow path switching valve, 8h Flow path switching valve, 8i Flow path switching valve, 8j Flow path switching valve, 8k Flow path switching valve, 8l Flow path switching valve, 10 First refrigerant circuit, 11 First intermediate heat exchanger, 12 First compressor, 13 First flow path switching device, 14 Heat source side heat exchanger, 15 First expansion mechanism, 16 Heat source side blower, 17 First pump, 20 Third refrigerant circuit, 21 Fourth intermediate heat exchanger, 22 Fifth intermediate heat exchanger, 23 Third compressor, 24 Third flow switching device, 25 Third expansion mechanism, 26 Third pump, 30 Load side heat exchanger, 31 Load side blower, 40 Second refrigerant circuit, 41 Second intermediate heat exchanger, 42 Third intermediate heat exchanger, 43 Second compressor, 44 Second flow switching device, 45 Second expansion mechanism, 46 Second pump, 70 Connecting piping, 71 Heat transfer medium circuit, 75 First heat medium circuit, 76 Second heat medium circuit, 77 Third heat medium circuit, 100 Air conditioning apparatus, 100L Air conditioning apparatus, 200 Building, 201 Hot water generating unit, 202 Branching section, 401 Hot and cold water generating unit, 402 Branching section, 402A Branching section, 402B Branching section, 402C Branching section.

Claims

1. A heat source system comprising: at least one heat source machine; at least one first relay machine connected to said at least one heat source machine; a plurality of second relay machines connected to said at least one first relay machine; a plurality of load devices connected to said plurality of second relay machines; and a plurality of connection pipes connecting said at least one heat source machine, said at least one first relay machine, said plurality of second relay machines, and said plurality of load devices; wherein said at least one heat source machine comprises: a first refrigerant circuit through which a refrigerant circulates, said first refrigerant circuit having a first intermediate heat exchanger for exchanging heat between the refrigerant flowing in said first refrigerant circuit and a heat transfer medium flowing therein, and a heat source side heat exchanger for exchanging heat between the refrigerant flowing in said first refrigerant circuit and air, and said at least one first relay machine comprises: an air conditioning apparatus comprising: 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 the heat transfer medium flowing therethrough; the plurality of second relay units comprising: a third refrigerant circuit through which a refrigerant circulates, the third refrigerant circuit having a fourth intermediate heat exchanger that performs heat exchange between the refrigerant flowing in the third refrigerant circuit and the heat transfer medium flowing therethrough, and a fifth intermediate heat exchanger that performs heat exchange between the refrigerant flowing in the third refrigerant circuit and the heat transfer medium flowing therethrough; and a heat transfer medium that flows between the at least one heat source unit, the at least one first relay unit, at least one of the plurality of second relay units, and at least one of the plurality of load devices via the plurality of connecting pipes.

2. The air conditioning apparatus according to claim 1, further comprising: a plurality of flow path switching valves connected to the plurality of connecting pipes and used to switch the flow path of the heat transfer medium to form one or more of the first heat transfer medium circuit, the first heat transfer medium circuit being configured to circulate through the heat transfer medium; a plurality of flow path switching valves connected to the plurality of connecting pipes and used to switch the flow path of the heat transfer medium to form one or more of the first heat transfer medium circuit, the second heat transfer medium circuit, and the third heat transfer medium circuit; 3. The air conditioning apparatus according to claim 1, further comprising: a plurality of flow path switching valves connected to the plurality of connecting pipes and used to switch the flow path of the heat transfer medium to form one or more of the first heat transfer medium circuit, the first intermediate heat exchanger, at least one of the second intermediate heat exchanger, at least one of the fourth intermediate heat exchanger, and at least one of the plurality of load devices, being connected to the plurality of connecting pipes, being at least one second heat transfer medium circuit, the heat transfer medium circulating; a plurality of flow path switching valves connected to the plurality of connecting pipes and used to switch the flow path of the heat transfer medium to form one or more of the first heat transfer medium circuit, the second heat transfer medium circuit, and the third heat transfer medium circuit.

4. An air conditioning apparatus according to claim 2 or 3, wherein each of the at least one first relay unit and the plurality of second relay units has a plurality of flow path switching valves.

5. An air conditioning apparatus as described in claim 2 or 3, wherein the plurality of flow path switching valves are provided in the plurality of second relay units and are also provided between the first relay unit and the plurality of second relay units.

6. An air conditioning apparatus according to any one of claims 2 to 5, configured so that the product of the flow rate of the heat transfer medium in each of the first heat medium circuit, the second heat medium circuit and the third heat medium circuit and the pressure loss of the heat transfer medium satisfies the following order: first heat medium circuit ≧ second heat medium circuit ≧ third heat medium circuit.

7. An air conditioning apparatus according to any one of claims 1 to 6, wherein the heat source unit and the first relay unit are connected by two of the connecting pipes, and the second relay unit and the load device are connected by two of the connecting pipes.

8. The air conditioning apparatus according to any one of claims 1 to 7, wherein in the first relay unit, 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 a heat transfer medium having a temperature range different from that of the heat transfer medium flowing through the second intermediate heat exchanger is generated in the third intermediate heat exchanger via the refrigerant flowing through the second refrigerant circuit by the heat transfer medium flowing through the second intermediate heat exchanger, and in the second relay unit, heat exchange occurs between the heat transfer medium flowing through the fourth intermediate heat exchanger and the refrigerant in the third refrigerant circuit, and heat exchange occurs between the heat transfer medium flowing through the fifth intermediate heat exchanger and the refrigerant in the third refrigerant circuit, and a heat transfer medium having a temperature range different from that of the heat transfer medium flowing through the fourth intermediate heat exchanger is generated in the fifth intermediate heat exchanger via the refrigerant flowing through the third refrigerant circuit by the heat transfer medium flowing through the fourth intermediate heat exchanger.

9. An air conditioning apparatus according to any one of claims 1 to 8, wherein the second refrigerant circuit of the first relay unit: absorbs heat from a first heat transfer medium flowing through one of the two connecting pipes connecting the heat source unit and the first relay unit, and imparts heat to a second heat transfer medium flowing in the fourth intermediate heat exchanger of at least one of the plurality of second relay units; or imparts heat to a first heat transfer medium flowing through one of the two connecting pipes connecting the heat source unit and the first relay unit, and absorbs heat from the second heat transfer medium flowing in the fourth intermediate heat exchanger of at least one of the plurality of second relay units, thereby changing the temperatures of the first heat transfer medium and the second heat transfer medium.

10. An air conditioning apparatus as described in any one of claims 1 to 9, wherein the third refrigerant circuit of the second relay unit changes the temperatures of the third heat transfer medium and the fourth heat transfer medium by: removing heat from a third heat transfer medium flowing through one of the two connecting pipes connecting the first relay unit and the second relay unit, and providing heat to a fourth heat transfer medium flowing in at least one of the multiple load devices, or by providing heat to the third heat transfer medium flowing through one of the two connecting pipes connecting the first relay unit and the second relay unit, and removing heat from the fourth heat transfer medium flowing in at least one of the multiple load devices.

11. An air conditioning apparatus according to claim 4 or 5, wherein the plurality of second relay units have the plurality of flow path switching valves that switch the supply of heat transfer medium to the plurality of load devices.

12. An air conditioning device as described in any one of claims 1 to 11, wherein the operating modes of the heat source unit and the at least one first relay unit are different, and the temperature of the heat transport medium sent from the heat source unit to the at least one first relay unit is different from the temperature of the heat transport medium sent from the at least one first relay unit to one or more of the plurality of second relay units.

13. An air conditioning apparatus as described in claim 12, wherein the operating modes of the heat source machine and the at least one first relay machine are different, and when the heat transport medium sent from the heat source machine to the at least one first relay machine is hot water, the heat transport medium sent from the at least one first relay machine to one or more of the plurality of second relay machines is cold water, and when the heat transport medium sent from the heat source machine to the at least one first relay machine is cold water, the heat transport medium sent from the at least one first relay machine to one or more of the plurality of second relay machines is hot water.

14. An air conditioning apparatus as described in claim 12 or 13, comprising a control device that controls the at least one heat source unit, the at least one first relay unit, the plurality of second 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 in the overall thermal load of the system, and controls all of the operating modes of the at least one first relay unit to be operating modes that have a smaller thermal load in the overall thermal load of the system.

15. An air conditioning system as described in any one of claims 1 to 14, wherein a plurality of the heat source units are installed in parallel, and two of the connection pipes connected to the at least one first relay unit branch off and are connected to each of the plurality of heat source units.

16. An air conditioning system as described in any one of claims 1 to 15, wherein a plurality of the first relay units are installed in parallel, and two of the connection pipes connected to the plurality of second relay units branch off and are connected to each of the plurality of first relay units.

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