Air conditioner

Abstract

This air conditioner comprises a heat source machine, a plurality of repeaters connected in series to the heat source machine, a plurality of load devices, and a plurality of heat medium pipes. The heat source machine is provided with a first refrigerant circuit. The first refrigerant circuit includes a first intermediate heat exchanger and a heat-source-side heat exchanger. Each of the plurality of repeaters is provided with a second refrigerant circuit. The second refrigerant circuits each include a second intermediate heat exchanger and a third intermediate heat exchanger. The first intermediate heat exchanger, the second intermediate heat exchangers, and load-side heat exchangers of a plurality of load devices are connected by the plurality of heat medium pipes. A first heat medium circuit through which a heat transfer medium circulates is formed. The plurality of heat medium pipes include two first heat medium pipes connecting the heat source machine and one relay device among the plurality of relay devices, three second heat medium pipes connecting the plurality of relay devices to each other, and two third heat medium pipes connecting each of the plurality of relay devices and each of the plurality of load devices.

Description

air conditioning equipment

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

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

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

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

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

[0006] An air conditioning apparatus according to the present disclosure includes a heat source unit, a plurality of relay units connected in series to the heat source unit via piping connections, a plurality of load devices connected to each of the plurality of relay units, and a plurality of heat medium pipes connecting the heat source unit, the plurality of relay units, and the plurality of load devices, wherein the 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 therethrough, and a heat source side heat exchanger that exchanges heat between the refrigerant flowing in the first refrigerant circuit and air, and each of the plurality of relay units includes a second refrigerant circuit through which a refrigerant circulates, the second 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 therethrough, and a third intermediate heat exchanger in which heat is exchanged between the refrigerant flowing in the second refrigerant circuit and the heat transfer medium flowing therethrough. The first intermediate heat exchanger, the second intermediate heat exchanger, and load-side heat exchangers of the plurality of load devices are connected by a plurality of heat medium pipes to form a first heat medium circuit in which the heat transfer medium circulates. The plurality of heat medium pipes include two first heat medium pipes connecting the heat source device and one of the plurality of relay devices, three second heat medium pipes connecting the plurality of relay devices together, and two third heat medium pipes connecting each of the plurality of relay devices to each of the plurality of load devices.

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

[0008] FIG. 1 is a configuration diagram that schematically shows an air conditioning apparatus according to embodiment 1. FIG. 2 is a circuit diagram that shows an example of an air conditioning apparatus according to embodiment 1. FIG. 3 is a circuit diagram that shows an example of a cooling operation mode in an air conditioning apparatus according to embodiment 1. FIG. 4 is a circuit diagram that shows an example of a heating operation mode in an air conditioning apparatus according to embodiment 1. FIG. 5 is a circuit diagram that shows an example of a cooling-dominated operation mode in an air conditioning apparatus according to embodiment 1. FIG. 6 is a circuit diagram that shows another example of a cooling-dominated operation mode in an air conditioning apparatus according to embodiment 1. FIG. 7 is a circuit diagram that shows another example of a heating-dominated operation mode in an air conditioning apparatus according to embodiment 1. FIG. 8 is a configuration diagram of another example that schematically shows an air conditioning apparatus according to embodiment 1. FIG. 9 is a circuit diagram that schematically shows 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 dashed arrows shown in Fig. 2 indicate an example of the flow of the heat transfer medium. The flow of the heat transfer medium is not limited to the flow shown in Fig. 2. Furthermore, the temperatures used in the following description are merely examples and are not limited to the temperatures described. The air conditioning apparatus 100 will be described using Figs. 1 and 2.

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

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

[0013] [Heat Source Unit 1] The air conditioning apparatus 100 includes a heat source unit 1. The heat source unit 1 is, for example, an outdoor unit. The heat source unit 1 is installed, for example, on the roof of a building 200. The heat source unit 1 includes a first refrigerant circuit 10 through which a refrigerant circulates.

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

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

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

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

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

[0019] The first expansion mechanism 7 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.

[0020] The first intermediate heat exchanger 9 exchanges heat between the heat transfer medium and the refrigerant. The first intermediate heat exchanger 9 is a flow path of the first refrigerant circuit 10 and a flow path of the heat transfer medium circuit 71 formed by the heat medium piping 70. That is, the first intermediate heat exchanger 9 is a component constituting the first refrigerant circuit 10 and a component constituting the heat transfer medium circuit 71 formed by the heat medium piping 70. The heat transfer medium circuit 71 includes a first heat medium circuit 75 described below. That is, the first intermediate heat exchanger 9 is a flow path of the first refrigerant circuit 10 and a flow path of the first heat medium circuit 75. That is, the first intermediate heat exchanger 9 is a component constituting the first refrigerant circuit 10 and a component constituting the first heat medium circuit 75.

[0021] During cooling operation, the first intermediate heat exchanger 9 functions as an evaporator, exchanging heat between the refrigerant flowing out from the first expansion mechanism 7 and the heat transfer medium, evaporating the refrigerant to vaporize it, and cooling the heat transfer medium. During heating operation, the first intermediate heat exchanger 9 functions as a condenser, exchanging heat between the refrigerant flowing in from the first compressor 12 and the heat transfer medium, condensing the refrigerant to liquefy it or to form a two-phase gas-liquid state, and heating the heat transfer medium.

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

[0023] [Relay unit 2] The air conditioning apparatus 100 is equipped with multiple relay units 2 connected to the heat source unit 1. The relay units 2 are installed, for example, inside a building 200. Note that in Figures 1 and 2, the air conditioning apparatus 100 is equipped with two relay units 2, relay unit 2A and relay unit 2B, but the air conditioning apparatus 100 may also be equipped with three or more relay units 2.

[0024] (Main body 120) Each of the multiple relay units 2 has a main body 120 that houses devices therein, as shown in Fig. 1. Each of the multiple relay units 2 has a first connection portion 91 and a third connection portion 93 that are connected to the heat source unit 1 or another relay unit 2 via the heat medium piping 70. Each of the multiple relay units 2 also has a second connection portion 92 that is connected to another relay unit 2 via the heat medium piping 70. Each of the multiple relay units 2 also has a fourth connection portion 94, a fifth connection portion 95, and a sixth connection portion 96 that are connected to the other relay units 2 via the heat medium piping 70.

[0025] The heat medium pipe 70 is connected to the first connection portion 91, the second connection portion 92, the third connection portion 93, the fourth connection portion 94, the fifth connection portion 95, and the sixth connection portion 96. The first connection portion 91, the second connection portion 92, the third connection portion 93, the fourth connection portion 94, the fifth connection portion 95, and the sixth connection portion 96 are provided in the main body portion 120 and are portions through which the heat transfer medium flows in and out of the main body portion 120. The first connection portion 91, the second connection portion 92, the third connection portion 93, the fourth connection portion 94, the fifth connection portion 95, and the sixth connection portion 96, which are not connected to the heat medium pipe 70, are sealed to prevent the heat transfer medium from flowing in or out.

[0026] In addition, each of the multiple relay units 2 has a first connection portion 191 on the load device side, a second connection portion 192 on the load device side, a third connection portion 193 on the load device side, and a fourth connection portion 194 on the load device side, which are connected to multiple load devices 3 via multiple heat medium pipes 70.

[0027] The heat medium piping 70 is connected to the load device side first connection portion 191, the load device side second connection portion 192, the load device side third connection portion 193, and the load device side fourth connection portion 194. The load device side first connection portion 191, the load device side second connection portion 192, the load device side third connection portion 193, and the load device side fourth connection portion 194 are provided in the main body portion 120, and are portions of the main body portion 120 through which the heat transfer medium flows in and out. The load device side first connection portion 191, the load device side second connection portion 192, the load device side third connection portion 193, and the load device side fourth connection portion 194, those connections to which the heat medium piping 70 is not connected, are sealed to prevent the heat transfer medium from flowing in or out.

[0028] 2, the repeater 2 has four load device side connections 190, namely, a first load device side connection portion 191, a second load device side connection portion 192, a third load device side connection portion 193, and a fourth load device side connection portion 194, but the number of load device side connections 190 is not limited to four. The load device side connection portion 190 is a collective term for the first load device side connection portion 191, the second load device side connection portion 192, the third load device side connection portion 193, and the fourth load device side connection portion 194. The number of load device side connections 190 may be more than one, and may be more or less than four depending on the number of load devices 3 connected to the repeater 2.

[0029] (Internal flow path of main body 120) Each of the multiple relay units 2 has a first flow path 41 that extends so that one end thereof becomes the first connection part 91 and the other end thereof becomes the fourth connection part 94. The first flow path 41 is a flow path for the heat transfer medium provided inside the relay unit 2, and is a flow path that penetrates between the first connection part 91 and the fourth connection part 94 inside the main body 120.

[0030] Each of the multiple relay units 2 has a second flow path 42 that extends so that one end thereof becomes the second connection part 92 and the other end thereof becomes the fifth connection part 95. The second flow path 42 is a flow path for the heat transfer medium provided inside the relay unit 2, and is a flow path that penetrates between the second connection part 92 and the fifth connection part 95 inside the main body part 120.

[0031] Each of the multiple relay units 2 has a third flow path 43 that extends so that one end thereof becomes the third connection part 93 and the other end thereof becomes the sixth connection part 96. The third flow path 43 is a flow path for the heat transfer medium provided inside the relay unit 2, and is a flow path that penetrates between the third connection part 93 and the sixth connection part 96 inside the main body part 120.

[0032] Each of the multiple relay units 2 has one end connected to the first flow path 41 and the other end branching into load device side connections 190 such as a load device side first connection part 191 and a load device side second connection part 192. The fourth flow path 44 is a flow path for the heat transfer medium provided inside the relay unit 2.

[0033] Each of the plurality of relay units 2 has one end connected to a second intermediate heat exchanger 28 (described later) and the other end branching into load device side connections 190 such as a load device side third connection 193 and a load device side fourth connection 194. The fifth flow path 45 is a flow path for the heat transfer medium provided inside the relay unit 2.

[0034] Each of the multiple relay units 2 has a sixth flow path 46 having one end connected to the third flow path 43 and the other end connected to the fifth flow path 45. One end of the sixth flow path 46 is connected in the third flow path 43 to a portion between a connection portion between a ninth flow path 49 and the third flow path 43, which will be described later, and a first flow control device 85, which will be described later. The other end of the sixth flow path 46 is connected in the fifth flow path 45 to a portion between a portion of the heat transfer medium inflow side of the second intermediate heat exchanger 28 and a second flow path switching device 62, which will be described later. The sixth flow path 46 is a flow path for the heat transfer medium provided inside the relay unit 2.

[0035] Each of the multiple relay units 2 has a seventh flow path 47, one end of which is connected to the second flow path 42 and the other end of which is connected to a second intermediate heat exchanger 28 (described later). One end of the seventh flow path 47 is connected to a portion of the second flow path 42 between the second connection part 92 and a connection part between a ninth flow path 49 (described later) and the second flow path 42. The seventh flow path 47 is a flow path for the heat transfer medium provided inside the relay unit 2.

[0036] Each of the multiple relay units 2 has an eighth flow path 48, one end of which is connected to the third flow path 43 and the other end of which is connected to the seventh flow path 47. One end of the eighth flow path 48 is connected to a portion of the third flow path 43 between the third connection unit 93 and a first flow control device 85, which will be described later. The other end of the eighth flow path 48 is connected to a portion of the seventh flow path 47 between a first opening and closing device 81, which will be described later, and a portion of the second intermediate heat exchanger 28 on the heat transfer medium outlet side. The eighth flow path 48 is a flow path for the heat transfer medium provided inside the relay unit 2.

[0037] Each of the multiple relay units 2 has a ninth flow path 49, one end of which is connected to the second flow path 42 and the other end of which is connected to the third flow path 43. The ninth flow path 49 has one end connected to the second flow path 42 between the connection portion of the second flow path 42 and the seventh flow path 47 and the fifth connection portion 95. The eighth flow path 48 has the other end connected to the third flow path 43 between the connection portion of the third flow path 43 and the sixth flow path 46 and the sixth connection portion 96. The ninth flow path 49 is a flow path for the heat transfer medium provided inside the relay unit 2.

[0038] The first flow path 41, the second flow path 42, the third flow path 43, the fourth flow path 44, the fifth flow path 45, the sixth flow path 46, the seventh flow path 47, the eighth flow path 48 and the ninth flow path 49 form part of the heat transfer medium circuit 71 inside the relay unit 2.

[0039] A heat transfer medium delivered by a first pump 11, which will be described later, flows through the first flow path 41, the second flow path 42, the third flow path 43, the fourth flow path 44, the fifth flow path 45, the sixth flow path 46, the seventh flow path 47, the eighth flow path 48, and the ninth flow path 49. That is, a heat transfer medium delivered from the heat source unit 1 flows through the first flow path 41, the second flow path 42, the third flow path 43, the fourth flow path 44, the fifth flow path 45, the sixth flow path 46, the seventh flow path 47, the eighth flow path 48, and the ninth flow path 49.

[0040] Each of the plurality of relay units 2 has a tenth flow path 51 that branches off so that one end thereof serves as the first inlet / outlet 29a for the heat transfer medium in the third intermediate heat exchanger 29 and the other end thereof serves as a load device side connection portion 190 such as a load device side first connection portion 191 and a load device side second connection portion 192. The tenth flow path 51 is a flow path for the heat transfer medium provided inside the relay unit 2.

[0041] Each of the multiple relay units 2 has an eleventh flow path 52 that branches off so that one end serves as the second inlet / outlet 29b for the heat transfer medium in the third intermediate heat exchanger 29 and the other end serves as a load device side connection 190 such as a load device side third connection 193 and a load device side fourth connection 194. The eleventh flow path 52 is a flow path for the heat transfer medium provided inside the relay unit 2. The heat transfer medium pumped out by a second pump 21 of the relay unit 2, which will be described later, flows through the tenth flow path 51 and the eleventh flow path 52.

[0042] A first opening and closing device 81 is provided in the seventh flow path 47. The first opening and closing device 81 is provided in a portion of the seventh flow path 47 between a connection portion between the seventh flow path 47 and the second flow path 42 and an outlet portion of the second intermediate heat exchanger 28 for the heat transfer medium.

[0043] A second opening and closing device 82 is provided in the sixth flow path 46. The second opening and closing device 82 is provided in a portion of the sixth flow path 46 between a connection portion between the sixth flow path 46 and the third flow path 43 and a connection portion between the sixth flow path 46 and the fifth flow path 45.

[0044] A third opening and closing device 83 is provided in the eighth flow path 48. The third opening and closing device 83 is provided in a portion of the eighth flow path 48 between a connection portion between the eighth flow path 48 and the third flow path 43 and a connection portion between the eighth flow path 48 and the seventh flow path 47.

[0045] A fourth opening and closing device 84 is provided in the ninth flow path 49. The fourth opening and closing device 84 is provided in a portion of the ninth flow path 49 between a connection portion between the ninth flow path 49 and the second flow path 42 and a connection portion between the ninth flow path 49 and the third flow path 43.

[0046] (Opening / Closing Device of Internal Flow Path, etc.) Each of the multiple relay units 2 has a first opening / closing device 81 provided on an internal pipe that connects the outlet side portion of the second intermediate heat exchanger 28 to the internal pipe that is connected to the heat accommodation pipe 73. The internal pipe that is connected to the heat accommodation pipe 73 constitutes the second flow path 42. The internal pipe that connects the outlet side portion of the second intermediate heat exchanger 28 to the internal pipe that is connected to the heat accommodation pipe 73 constitutes the seventh flow path 47.

[0047] Each of the multiple relay units 2 has a first relay unit piping 46A that connects an internal piping connected to a return piping 74 (described later) with an internal piping on the inlet side of the second intermediate heat exchanger 28. The internal piping connected to the return piping 74 constitutes a third flow path 43, and the internal piping on the inlet side of the second intermediate heat exchanger 28 constitutes a fifth flow path 45. The first relay unit piping 46A constitutes a sixth flow path 46. Each of the multiple relay units 2 has a second opening and closing device 82 provided on the first relay unit piping 46A.

[0048] Each of the multiple relay units 2 has an internal pipe connecting the second intermediate heat exchanger 28 and the first opening and closing device 81, and a second relay pipe 48A connecting an internal pipe connected to the return pipe 74 and downstream of the connection portion of the first relay pipe 46A. The internal pipe connecting the second intermediate heat exchanger 28 and the first opening and closing device 81 constitutes a part of the seventh flow path 47. The internal pipe connected to the return pipe 74 constitutes the third flow path 43. The second relay pipe 48A constitutes the eighth flow path 48. Each of the multiple relay units 2 has a third opening and closing device 83 provided on the second relay pipe 48A.

[0049] Each of the multiple relay units 2 has a fourth opening and closing device 84 provided on an internal pipe connecting an internal pipe connected to the return pipe 74 and an internal pipe connected to the heat accommodation pipe 73. The internal pipe connected to the return pipe 74 constitutes the third flow path 43, and the internal pipe connected to the heat accommodation pipe 73 constitutes the second flow path 42. The internal pipe connecting the internal pipe connected to the return pipe 74 and the internal pipe connected to the heat accommodation pipe 73 constitutes the ninth flow path 49.

[0050] The first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, and the fourth opening and closing device 84 are configured, for example, as two-way valves, and opening and closing thereof are controlled by the control device 40. Note that the first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, and the fourth opening and closing device 84 may be configured, for example, as two-way valves that can control the opening degree (opening area) of the valves.

[0051] The first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, and the fourth opening and closing device 84 are controlled to open and close, thereby controlling the flow of the heat transfer medium inside the relay unit 2. The first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, and the fourth opening and closing device 84 are controlled to open and close, thereby controlling the flow of the heat transfer medium flowing in and out of the relay unit 2 with respect to the heat source unit 1.

[0052] Furthermore, the first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, and the fourth opening and closing device 84 are controlled to open and close, thereby controlling the flow of the heat transfer medium flowing in and out of the load-side heat exchanger 30 of the load device 3. Furthermore, the first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, and the fourth opening and closing device 84 are controlled to open and close, thereby controlling the flow of the heat transfer medium flowing in and out of adjacent relay units 2.

[0053] A first flow control device 85 that adjusts the flow rate of the heat transfer medium is provided in the third flow path 43. The first flow control device 85 is provided in the third flow path 43 between the connection between the third flow path 43 and the eighth flow path 48 and the connection between the third flow path 43 and the sixth flow path 46.

[0054] Each of the multiple relay units 2 has a first flow control device 85 that adjusts the flow rate of the heat transfer medium flowing through the return pipe 74, on the internal pipe between the connection part of the first relay pipe 46A and the connection part of the second relay pipe 48A on the internal pipe connected to the return pipe 74. The internal pipe connected to the return pipe 74 configures the third flow path 43.

[0055] The first flow control device 85 is configured, for example, as a two-way valve, and its opening and closing is controlled by the control device 40. The first flow control device 85 may be configured, for example, as a two-way valve that can control the valve opening (opening area). The first flow control device 85 controls the flow of the heat transfer medium inside the relay unit 2 by controlling its opening and closing.

[0056] Furthermore, the first flow control device 85, by controlling the opening and closing thereof, controls the flow of the heat transfer medium flowing in and out of the relay unit 2 for the heat source unit 1. Furthermore, the first flow control device 85, by controlling the opening and closing thereof, controls the flow of the heat transfer medium flowing in and out of the load-side heat exchanger 30 of the load device 3. Furthermore, the first flow control device 85, by controlling the opening and closing thereof, controls the flow of the heat transfer medium flowing in and out of adjacent relay units 2.

[0057] 2 , the first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, the fourth opening and closing device 84, the first flow rate adjustment device 85, etc. are housed in the relay unit 2. The air conditioning unit 100 is not limited to this configuration, and the first opening and closing device 81, the second opening and closing device 82, the third opening and closing device 83, the fourth opening and closing device 84, the first flow rate adjustment device 85, etc. may be installed outside the relay unit 2.

[0058] (Second refrigerant circuit 20) Each of the multiple relay units 2 includes a second refrigerant circuit 20 through which a refrigerant circulates. The second refrigerant circuit 20 has a second intermediate heat exchanger 28 through which the refrigerant flowing in the second refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therein, and a third intermediate heat exchanger 29 through which the refrigerant flowing in the second refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therein. The relay unit 2 has the second refrigerant circuit 20 through which a refrigerant circulates, the second intermediate heat exchanger 28 through which the refrigerant flowing in the second refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therein, and the third intermediate heat exchanger 29 through which the refrigerant flowing in the second refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therein.

[0059] In addition, the relay unit 2 is connected to a flow path formed by a plurality of heat medium pipes 70, and has a plurality of first flow path switching devices 61 and a plurality of second flow path switching devices 62 that switch the flow path of the heat transfer medium flowing into the load device 3 to a first heat medium circuit 75 or a second heat medium circuit 76 described below.

[0060] As described above, the relay unit 2 has the second refrigerant circuit 20 through which the refrigerant circulates. The second refrigerant circuit 20 has a configuration in which a second compressor 22, a second flow switching valve 26, a second intermediate heat exchanger 28, a second expansion mechanism 27, and a third intermediate heat exchanger 29 are connected in this order by refrigerant piping. Note that the second refrigerant circuit 20 may include other components in addition to the above-described components, or may omit some components.

[0061] The second compressor 22 draws in low-temperature, low-pressure refrigerant, compresses the drawn refrigerant, and discharges high-temperature, high-pressure refrigerant. The second compressor 22 is, for example, an inverter compressor and has basically the same configuration as the first compressor 12. The refrigerant discharged from the second compressor 22 flows into the second intermediate heat exchanger 28 or the third intermediate heat exchanger 29 via a second flow path switching valve 26.

[0062] The second flow path switching valve 26 is, for example, a four-way valve that has the function of switching the flow path of the refrigerant. The second flow path switching valve 26 basically has the same configuration as the first flow path switching valve 6. Note that the second flow path switching valve 26 may be configured by combining two-way valves or three-way valves. The second refrigerant circuit 20 can switch between cooling and heating operation by the second flow path switching valve 26.

[0063] During cooling operation of the load device 3, the second flow path switching valve 26 switches the refrigerant flow path to connect the refrigerant discharge side of the second compressor 22 to the second intermediate heat exchanger 28 and to connect the refrigerant suction side of the second compressor 22 to the third intermediate heat exchanger 29. On the other hand, during heating operation of the load device 3, the second flow path switching valve 26 switches the refrigerant flow path to connect the refrigerant discharge side of the second compressor 22 to the third intermediate heat exchanger 29 and to connect the refrigerant suction side of the second compressor 22 to the second intermediate heat exchanger 28.

[0064] The second expansion mechanism 27 reduces the pressure of the refrigerant circulating in the second refrigerant circuit 20 to expand it, and is configured, for example, by an electronic expansion valve whose opening degree is variably controlled.

[0065] The second intermediate heat exchanger 28 exchanges heat between the heat transfer medium and the refrigerant. The second intermediate heat exchanger 28 is a flow path of the second refrigerant circuit 20 and a flow path of the heat transfer medium circuit 71 formed by the heat medium piping 70. In other words, the second intermediate heat exchanger 28 is a component constituting the second refrigerant circuit 20 and a component constituting the heat transfer medium circuit 71 formed by the heat medium piping 70. In the second intermediate heat exchanger 28 shown in FIG. 2 , particularly when functioning as a condenser, it is preferable to configure the piping so that the refrigerant circulating through the second refrigerant circuit 20 and the heat transfer medium circulating through the heat transfer medium circuit 71 flow in counterflow directions to increase the heat exchange rate in the second intermediate heat exchanger 28.

[0066] More specifically, the second intermediate heat exchanger 28 serves as a flow path of the second refrigerant circuit 20 and a flow path of a first heat medium circuit 75 described later. That is, the second intermediate heat exchanger 28 serves as a component of the second refrigerant circuit 20 and a component of the first heat medium circuit 75. In the second intermediate heat exchanger 28 shown in FIG. 2 , particularly when functioning as a condenser, it is preferable to configure the piping so that the refrigerant circulating through the second refrigerant circuit 20 and the heat transfer medium circulating through the first heat medium circuit 75 flow in counter directions, thereby increasing the heat exchange rate in the second intermediate heat exchanger 28. Alternatively, in the second intermediate heat exchanger 28, particularly when functioning as a condenser, it is preferable to configure the piping so that the refrigerant circulating through the second refrigerant circuit 20 and the heat transfer medium circulating through a third heat medium circuit 77 described later flow in counter directions, thereby increasing the heat exchange rate in the second intermediate heat exchanger 28.

[0067] When functioning as a condenser, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through the heat medium 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 a condenser, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through a first heat medium circuit 75 (described later) and the like, condensing the refrigerant to liquefy or to form a gas-liquid two-phase mixture, and heating the heat transfer medium. When functioning as a condenser, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through a first heat medium pipe 70A (described later), condensing the refrigerant to liquefy or to form a gas-liquid two-phase mixture, and heating the heat transfer medium.

[0068] When functioning as an evaporator, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing out from the second expansion mechanism 27 and the heat transfer medium circulating through the heat medium pipe 70, evaporating and vaporizing the refrigerant and cooling the heat transfer medium. When functioning as an evaporator, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing out from the second expansion mechanism 27 and the heat transfer medium circulating through a first heat medium circuit 75 (described later) or the like, evaporating and vaporizing the refrigerant and cooling the heat transfer medium. When functioning as an evaporator, the second intermediate heat exchanger 28 exchanges heat between the refrigerant flowing out from the second expansion mechanism 27 and the heat transfer medium circulating through a first heat medium pipe 70A (described later), evaporating and vaporizing the refrigerant and cooling the heat transfer medium.

[0069] The third intermediate heat exchanger 29 exchanges heat between the heat transfer medium and the refrigerant. The third intermediate heat exchanger 29 is a flow path of the second refrigerant circuit 20 and a flow path of the heat transfer medium circuit 71 formed by the heat medium piping 70. In other words, the third intermediate heat exchanger 29 is a component constituting the second refrigerant circuit 20 and a component constituting the heat transfer medium circuit 71 formed by the heat medium piping 70. In the third intermediate heat exchanger 29 shown in FIG. 2 , particularly when functioning as a condenser, it is preferable to configure the piping so that the refrigerant circulating through the second refrigerant circuit 20 and the heat transfer medium circulating through the heat transfer medium circuit 71 flow in counterflow directions to increase the heat exchange rate in the third intermediate heat exchanger 29.

[0070] More specifically, the third intermediate heat exchanger 29 serves as a flow path of the second refrigerant circuit 20 and a flow path of the second heat medium circuit 76 described below. That is, the third intermediate heat exchanger 29 serves as a component of the second refrigerant circuit 20 and a component of the second heat medium circuit 76. In the third intermediate heat exchanger 29 shown in Fig. 2 , particularly when functioning as a condenser, it is preferable to configure the piping so that the refrigerant circulating through the second refrigerant circuit 20 and the heat transfer medium circulating through the second heat medium circuit 76 flow in counter directions to increase the heat exchange efficiency in the third intermediate heat exchanger 29.

[0071] When functioning as an evaporator, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing out from the second expansion mechanism 27 and the heat transfer medium circulating through the heat medium pipe 70, evaporating and vaporizing the refrigerant and cooling the heat transfer medium. When functioning as an evaporator, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing out from the second expansion mechanism 27 and the heat transfer medium circulating through a second heat medium circuit 76 described later, evaporating and vaporizing the refrigerant and cooling the heat transfer medium.

[0072] When the third intermediate heat exchanger 29 functions as an evaporator, it exchanges heat between the refrigerant flowing out of the second expansion mechanism 27 and the heat transfer medium circulating through the second heat medium piping 70B described later, evaporating and vaporizing the refrigerant and cooling the heat medium transfer body.

[0073] When functioning as a condenser, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through the heat medium pipe 70, condenses the refrigerant to liquefy or to form a gas-liquid two-phase mixture, and heats the heat transfer medium. When functioning as a condenser, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through a second heat medium circuit 76 described later, condenses the refrigerant to liquefy or to form a gas-liquid two-phase mixture, and heats the heat transfer medium.

[0074] When functioning as a condenser, the third intermediate heat exchanger 29 exchanges heat between the refrigerant flowing in from the second compressor 22 and the heat transfer medium circulating through the second heat medium piping 70B described later, condenses the refrigerant to liquefy or convert it into a gas-liquid two-phase mixture, and heats the heat transfer medium.

[0075] The second refrigerant circuit 20 is filled with a non-flammable or slightly flammable refrigerant, such as R410A, R32, olefin, or a mixture of these refrigerants. This is because the relay unit 2 is mainly installed indoors. The refrigerant filled in the second refrigerant circuit 20 is not limited to the above refrigerants, and may be any refrigerant commonly used in air conditioners today, such as R410A or R32, R290, CO ２ , N.H. ３ The refrigerant sealed in the second refrigerant circuit 20 is, in consideration of safety, for example, R290, NH３ A flammable refrigerant such as olefin may be enclosed.

[0076] The amount of refrigerant circulating through the first refrigerant circuit 10 is greater than the amount of refrigerant circulating through the second refrigerant circuit 20. The amount of refrigerant charged in the first refrigerant circuit 10 is, for example, 5 kg or less. The amount of refrigerant charged in the second refrigerant circuit 20 is, for example, less than 1 kg, which is the standard for using a flammable refrigerant indoors. The first refrigerant circuit 10 is mainly used for load devices 3 with heavy operating loads. In other words, in order to improve operating efficiency, the air conditioning apparatus 100 has a greater amount of refrigerant circulating through the first refrigerant circuit 10 than the amount of refrigerant circulating through the second refrigerant circuit 20.

[0077] In the air conditioning apparatus 100 according to the first embodiment, as an example, the second refrigerant circuit 20 in the relay unit 2 is operated, and the heat transfer medium flowing out from the heat source unit 1 is sent to the load device 3 without passing through the second intermediate heat exchanger 28 and the third intermediate heat exchanger 29 of the second refrigerant circuit 20. In the air conditioning apparatus 100 according to the first embodiment, the heat transfer medium returning from the load device 3 passes through the second intermediate heat exchanger 28 and returns to the heat source unit 1, and the circulating water of the heat source unit 1 may be used as a heat source. The heat transfer medium passing through the third intermediate heat exchanger 29 of the second refrigerant circuit 20 circulates only between the relay unit 2 and the load device 3. Note that if the air conditioning apparatus 100 is a chiller type, for example, the second refrigerant circuit 20 in the relay unit 2 is stopped, and the heat transfer medium from the heat source unit 1 is sent to the load device 3 and returned to the heat source unit 1.

[0078] (Flow path switching device) The relay unit 2 has a plurality of first flow path switching devices 61 and a plurality of second flow path switching devices 62. The plurality of first flow path switching devices 61 and the plurality of second flow path switching devices 62 switch the flow path of the heat transfer medium flowing into the load device 3 in the relay unit 2 to the first heat medium circuit 75 or the second heat medium circuit 76. Furthermore, the plurality of first flow path switching devices 61 and the plurality of second flow path switching devices 62 switch the flow path of the heat transfer medium flowing into the load device 3 in the relay unit 2 to the third heat medium circuit 77 or the second heat medium circuit 76.

[0079] The plurality of first flow switching devices 61 are provided in the relay unit 2 on the outflow side of the heat transfer medium flowing from the relay unit 2 to the load device 3. The first flow switching devices 61 are provided in the first heat medium circuit 75 on the refrigerant inflow side of the load side heat exchanger 30. The first flow switching devices 61 are also provided in the second heat medium circuit 76 on the refrigerant inflow side of the load side heat exchanger 30. The first flow switching devices 61 are also provided in the third heat medium circuit 77 on the refrigerant inflow side of the load side heat exchanger 30.

[0080] The plurality of first flow path switching devices 61 are configured, for example, as three-way valves, and their opening and closing is controlled by the control device 40 or by a person. The flow paths of the first flow path switching devices 61 are switched by the control device 40 or by a person. The first flow path switching devices 61 may be configured, for example, as two-way valves, and their opening and closing is controlled by the control device 40. The first flow path switching devices 61 may be configured, for example, as two-way valves whose valve opening degree (opening area) can be controlled. The first flow path switching devices 61 are controlled to open and close, thereby controlling the inflow and outflow of the heat transfer medium flowing through the load-side heat exchanger 30.

[0081] The plurality of second flow switching devices 62 are provided in the relay unit 2 on the inflow side of the heat transfer medium flowing from the load device 3 to the relay unit 2. The second flow switching devices 62 are provided in the first heat medium circuit 75 on the refrigerant outflow side of the load side heat exchanger 30. In addition, the second flow switching devices 62 are provided in the second heat medium circuit 76 on the refrigerant outflow side of the load side heat exchanger 30. In addition, the second flow switching devices 62 are provided in the third heat medium circuit 77 on the refrigerant outflow side of the load side heat exchanger 30.

[0082] The plurality of second flow path switching devices 62 are configured, for example, as three-way valves, and their opening and closing is controlled by the control device 40 or by a person. The flow paths of the second flow path switching devices 62 are switched by the control device 40 or by a person. The second flow path switching devices 62 may be configured, for example, as two-way valves, and their opening and closing is controlled by the control device 40. The second flow path switching devices 62 may be configured, for example, as two-way valves whose valve opening (opening area) can be controlled. The second flow path switching devices 62 control the inflow and outflow of the heat transfer medium flowing through the load-side heat exchanger 30 by controlling their opening and closing.

[0083] In the relay 2, the first flow path switching device 61 includes a first flow path switching device 61a and a first flow path switching device 61b. Also, in the relay 2, the second flow path switching device 62 includes a second flow path switching device 62a and a second flow path switching device 62b. The first flow path switching device 61 may include a first flow path switching device 61c, and the second flow path switching device 62 may include a second flow path switching device 62c. In other words, the first flow path switching device 61 and the second flow path switching device 62 are not limited to two each, and may each be one, or more than two each.

[0084] The first flow path switching device 61a is provided at the junction of one of the branched flow paths of the fourth flow path 44 and one of the branched flow paths of the tenth flow path 51, and switches the flow path of the heat transfer medium flowing through the load device side first connection part 191. The first flow path switching device 61b is provided at the junction of the other of the branched flow paths of the fourth flow path 44 and another of the branched flow paths of the tenth flow path 51, and switches the flow path of the heat transfer medium flowing through the load device side second connection part 192.

[0085] The second flow path switching device 62a is provided at the junction of one of the branched flow paths of the eleventh flow path 52 and one of the branched flow paths of the fifth flow path 45, and switches the flow path of the heat transfer medium flowing through the load device side third connection part 193. The second flow path switching device 62b is provided at the junction of the other of the branched flow paths of the eleventh flow path 52 and another of the branched flow paths of the fifth flow path 45, and switches the flow path of the heat transfer medium flowing through the load device side fourth connection part 194.

[0086] The first flow path switching device 61 of the relay unit 2 is arranged downstream of the second pump 21 in the flow direction of the heat transfer medium formed by the second pump 21 (described later). The first flow path switching device 61 is arranged downstream of the third intermediate heat exchanger 29 in the flow direction of the heat transfer medium formed by the second pump 21 (described later). The first flow path switching device 61a and the first flow path switching device 61b are arranged in parallel in the flow path through which the heat transfer medium formed by the second pump 21 flows.

[0087] At least the first flow path switching device 61 in the relay unit 2 closest to the heat source unit 1 is arranged downstream of the first pump 11 in the flow direction of the heat transfer medium formed by the first pump 11 described below. At least the first flow path switching device 61 in the relay unit 2 closest to the heat source unit 1 is arranged downstream of the first intermediate heat exchanger 9 in the flow of the heat transfer medium caused by the first pump 11. At least the first flow path switching device 61a and the first flow path switching device 61b in the relay unit 2 closest to the heat source unit 1 are arranged in parallel in the flow path in which the heat transfer medium caused by the first pump 11 flows.

[0088] The second flow path switching device 62 of the relay unit 2 is arranged upstream of the second pump 21 in the flow direction of the heat transfer medium formed by the second pump 21 (described later). The second flow path switching device 62 is arranged upstream of the third intermediate heat exchanger 29 in the flow direction of the heat transfer medium formed by the second pump 21 (described later). The second flow path switching device 62a and the second flow path switching device 62b are arranged in parallel in the flow path through which the heat transfer medium formed by the second pump 21 flows.

[0089] The second flow path switching device 62 may be arranged upstream of the first pump 11 in the flow direction of the heat transfer medium formed by the first pump 11, which will be described later. The second flow path switching device 62 may be arranged upstream of the second intermediate heat exchanger 28 in the flow of the heat transfer medium caused by the first pump 11. The second flow path switching device 62a and the second flow path switching device 62b may be arranged in parallel in the flow path in which the heat transfer medium caused by the first pump 11 flows.

[0090] [Load Device 3] The air conditioning apparatus 100 has a plurality of load devices 3 connected to a plurality of relay units 2. One example of the load devices 3 is an indoor unit. The load devices 3 are installed, for example, inside a building 200. Note that in FIG. 2 , the air conditioning apparatus 100 has two load devices 3, load device 3A and load device 3B, connected to the relay unit 2, but the number of load devices 3 connected to the relay unit 2 may be one, or three or more.

[0091] 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.

[0092] 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.

[0093] [Heat medium piping 70] The air conditioning apparatus 100 includes a plurality of heat medium piping 70 that connects the heat source unit 1, a plurality of relay units 2, and a plurality of load devices 3. The heat medium piping 70 connects the heat source unit 1 and the relay units 2. The heat medium piping 70 connects the relay units 2 and the load devices 3. The heat medium piping 70 constitutes a heat transfer medium circuit 71 through which a heat transfer medium flows.

[0094] A heat transfer medium flows in a heat transfer medium circuit 71 constituted by heat medium piping 70. The heat transfer medium is, for example, water or brine, or a mixture of brine and water. In the air conditioning apparatus 100, the heat source unit 1 and the relay unit 2 are connected by two heat medium piping 70, and the relay unit 2 is connected to each of the multiple load devices 3 by two heat medium piping 70. In the air conditioning apparatus 100, the relay unit 2 is connected to another relay unit 2 by three heat medium piping 70.

[0095] The plurality of heat medium pipes 70 include two first heat medium pipes 70A connecting the heat source unit 1 and one of the plurality of relay units 2, and three second heat medium pipes 70B connecting the plurality of relay units 2. The plurality of heat medium pipes 70 also include two third heat medium pipes 70C connecting each of the plurality of relay units 2 and each of the plurality of load devices 3.

[0096] Here, of the multiple relay units 2 connected in series, the relay unit 2 connected to the heat source unit 1 is referred to as the nearest relay unit 2F, and of the multiple relay units 2 connected in series, the relay unit 2 connected to the position farthest from the heat source unit 1 is referred to as the farthest relay unit 2L. The second heat medium piping 70B includes an outgoing pipe 72 through which the heat transfer medium supplied from the heat source unit 1 to the multiple relay units 2 flows, and a heat accommodation pipe 73 through which the heat transfer medium flows from the nearest relay unit 2F toward the farthest relay unit 2L. The second heat medium piping 70B also includes a return pipe 74 through which the heat transfer medium flowing out of the farthest relay unit 2L flows toward the heat source unit 1.

[0097] The first heat medium piping 70A includes a forward piping 72 through which the heat transfer medium supplied from the heat source unit 1 to the multiple relay units 2 flows, and a return piping 74 through which the heat transfer medium flowing out from the farthest relay unit 2L flows toward the heat source unit 1.

[0098] [Control device 40] The control device 40 controls the overall operation of the air conditioning apparatus 100. The control device 40 controls the heat source unit 1, the multiple relay units 2, and the multiple load devices 3. Specifically, the control device 40 controls the compressor drive frequency, the number of rotations 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 pump drive frequency, etc. The control device 40 is composed of a computer equipped with a memory that stores data and programs required for control and a CPU that executes programs, dedicated hardware such as an ASIC or FPGA, or both.

[0099] [Example of heat transfer medium circuit 71 of air conditioning apparatus 100] The air conditioning apparatus 100 is 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.

[0100] In the first heat medium circuit 75, the first intermediate heat exchanger 9, the second intermediate heat exchanger 28, and the load side heat exchangers 30 of the plurality of load devices 3 are connected by a plurality of heat medium pipes 70, and a heat transfer medium circulates. In the air conditioning apparatus 100, the first intermediate heat exchanger 9, the second intermediate heat exchanger 28, and the load side heat exchangers 30 are connected by the heat medium pipes 70, forming the first heat medium circuit 75 through which the heat transfer medium circulates. In the air conditioning apparatus 100, the first heat medium circuit 75 is formed so that the heat transfer medium circulates between the heat source device 1 and the load device 3 via the relay unit 2.

[0101] The first heat medium circuit 75 includes a circuit configured by sequentially connecting with piping the first intermediate heat exchanger 9, the supply pipe 72, the first flow switching device 61, the load-side heat exchanger 30, the second flow switching device 62, the second intermediate heat exchanger 28, the heat accommodation pipe 73, and the return pipe 74. Such a heat transfer medium circuit 71 is a circuit when, for example, the heat transfer medium sent from the heat source unit 1 flows through the load device 3 connected to the relay unit 2A.

[0102] The first heat medium circuit 75 includes a circuit configured by sequentially connecting with piping the first intermediate heat exchanger 9, the supply pipe 72, the first flow switching device 61, the load-side heat exchanger 30, the second flow switching device 62, the second intermediate heat exchanger 28, and the return pipe 74. Such a heat transfer medium circuit 71 is a circuit, for example, when the heat transfer medium sent from the heat source unit 1 flows through the load device 3 connected to the relay unit 2B.

[0103] The second heat medium circuit 76 connects the relay unit 2 and the load device 3 by a plurality of heat medium pipes 70. The air conditioning device 100 is configured so that the heat transfer medium circulates through the second heat medium circuit 76. The air conditioning device 100 is configured so that the heat transfer medium circulates between the relay unit 2 and the load device 3 in the second heat medium circuit 76.

[0104] In the second heat medium circuit 76, the third intermediate heat exchanger 29 and the load side heat exchanger 30 are connected by a third heat medium pipe 70C. In the air conditioning apparatus 100, the third intermediate heat exchanger 29 and the load side heat exchanger 30 are connected by a heat medium pipe 70 to form the second heat medium circuit 76 through which the heat transfer medium circulates. More specifically, the second heat medium circuit 76 includes a circuit configured by sequentially connecting the third intermediate heat exchanger 29, the first flow switching device 61, the load side heat exchanger 30, and the second flow switching device 62 by piping.

[0105] The first heat medium circuit 75 and the second heat medium circuit 76 are provided with a first flow path switching device 61 and a second flow path switching device 62 that switch the flow path of the heat transfer medium flowing into the load side heat exchanger 30 to the first heat medium circuit 75 or the second heat medium circuit 76.

[0106] The air conditioning apparatus 100 may be formed with a third heat medium circuit 77. The third heat medium circuit 77 is configured by connecting a heat source unit 1, a plurality of relay units 2, and a plurality of load devices 3 via a plurality of heat medium pipes 70. The air conditioning apparatus 100 is configured so that a heat transfer medium circulates through the third heat medium circuit 77. The air conditioning apparatus 100 is configured so that a heat transfer medium circulates between the heat source unit 1, the relay unit 2, and the load devices 3 in the third heat medium circuit 77. A portion of the flow path of the third heat medium circuit 77 overlaps with the first heat medium circuit 75. In other words, the third heat medium circuit 77 partially includes the first heat medium circuit 75.

[0107] In the third heat medium circuit 77, the heat transfer medium sequentially flows through the first intermediate heat exchanger 9, the supply pipe 72, the first flow switching device 61 of at least one relay unit 2 among the multiple relay units 2, the load side heat exchanger 30, the second flow switching device 62, the second intermediate heat exchanger 28, and the heat accommodation pipe 73. Then, in the third heat medium circuit 77, the heat transfer medium sequentially flows through the first relay unit pipe 46A of at least another one of the multiple relay units 2, the second intermediate heat exchanger 28, the second relay unit pipe 48A, and the return pipe 74. Thereafter, the heat transfer medium passes through at least one relay unit 2 among the multiple relay units 2 and returns to the first intermediate heat exchanger 9.

[0108] The third heat medium circuit 77 partially includes the first heat medium circuit 75. Therefore, the third heat medium circuit 77 and the second heat medium circuit 76 are provided with a first flow path switching device 61 and a second flow path switching device 62 that switch the flow path of the heat transfer medium flowing into the load side heat exchanger 30 to the third heat medium circuit 77 or the second heat medium circuit 76.

[0109] (Pump of Heat Transfer Medium Circuit 71) The first heat medium circuit 75 is provided with a first pump 11 that circulates the heat transfer medium. The first pump 11 is one of the devices that make up the first heat medium circuit 75, and is provided in the heat source unit 1, as an example. The first pump 11 sucks the heat transfer medium in the first heat medium circuit 75, applies pressure to it, and sends it out to circulate it. The capacity of the first pump 11 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the first pump 11 by arbitrarily changing the drive frequency based on instructions from the control device 40.

[0110] In FIG. 2 , the first pump 11 is provided in the heat source unit 1, but the installation location of the first pump 11 is not limited to the heat source unit 1. The first pump 11 may also be provided in, for example, the relay unit 2. Furthermore, the first pump 11 may also be provided in each of the heat source unit 1 and the relay unit 2. In FIG. 2 , there is one first pump 11, but the number of first pumps 11 is not limited to one and may be multiple. For example, the first pump 11 may be provided in each of the multiple relay units 2. The air conditioning apparatus 100 shown in FIG. 2 is configured to connect one first pump 11 in consideration of the pressure loss of the heat transfer medium flowing between the heat source unit 1 and the load device 3.

[0111] The second heat medium circuit 76 is provided with a second pump 21 that circulates the heat transfer medium. The second pump 21 is one of the devices that make up the second heat medium circuit 76, and is provided in the relay unit 2, for example. The second pump 21 sucks the heat transfer medium in the second heat medium circuit 76, applies pressure to it, and sends it out to circulate. The capacity of the second pump 21 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the second pump 21 by arbitrarily changing the drive frequency based on instructions from the control device 40.

[0112] The second pump 21 has a smaller flow rate or head than the first pump 11. The second heat medium circuit 76 connects the relay unit 2 and the load device 3, and the length of the flow path of the heat transfer medium circuit 71 is shorter than that of the first heat medium circuit 75, which also connects the heat source unit 1, and the pressure loss is not as large. Making the second pump 21 smaller than the first pump 11 reduces costs and the burden of installation work. The second pump 21 may have the same flow rate or head as the first pump 11.

[0113] The size of the pump is determined, for example, by the transport distance of the heat transport medium. The size of the pump is determined, for example, by the electric input W = ΔP × V, where ΔP is the pressure loss (corresponding to the pump head) [unit: kPa, for example] in the heat transport medium circuit 71, and V is the volumetric flow rate [unit: m ３ / s].

[0114] In the air conditioning apparatus 100, for example, in one or more of the multiple relay units 2, heat exchange occurs between the heat transfer medium flowing through the second intermediate heat exchanger 28 and the refrigerant in the second refrigerant circuit 20, and heat exchange occurs between the heat transfer medium flowing through the third intermediate heat exchanger 29 and the refrigerant in the second refrigerant circuit 20. In the relay unit 2, a heat transfer medium having a temperature range different from that of the heat transfer medium flowing through the second intermediate heat exchanger 28 is generated in the third intermediate heat exchanger 29 via the refrigerant flowing through the second refrigerant circuit 20 by the heat transfer medium flowing through the second intermediate heat exchanger 28.

[0115] In the air conditioning apparatus 100, the second refrigerant circuit 20 of the relay unit 2 removes heat from a first heat transfer medium flowing through one of two heat medium pipes 70 connecting the heat source unit 1 and the relay unit 2. The second refrigerant circuit 20 of the relay unit 2 provides heat to a second heat transfer medium flowing through one of two heat medium pipes 70 connecting the relay unit 2 and the load devices 3, and provides heat to the second heat transfer medium flowing through at least one load-side heat exchanger 30 of the multiple load devices 3.

[0116] Alternatively, in the air conditioning apparatus 100, the second refrigerant circuit 20 of the relay unit 2 provides heat to a first heat transfer medium flowing through one of two heat medium pipes 70 connecting the heat source unit 1 and the relay unit 2. The second refrigerant circuit 20 of the relay unit 2 removes heat from a second heat transfer medium flowing through one of two heat medium pipes 70 connecting the relay unit 2 and the load devices 3, and removes heat from the second heat transfer medium flowing through at least one load-side heat exchanger 30 of the multiple load devices 3.

[0117] In the air conditioning apparatus 100, the second refrigerant circuit 20 of the relay unit 2 changes the temperatures of the first heat transfer medium and the second heat transfer medium. The first heat transfer medium is the heat transfer medium that flows through the first heat medium circuit 75 or the third heat medium circuit 77, and the second heat transfer medium is the heat transfer medium that flows through the second heat medium circuit 76.

[0118] Next, the operating behavior of the air conditioning apparatus 100 during various operations will be described. The air conditioning apparatus 100 has four operating modes: cooling operation mode, heating operation mode, cooling-dominated operation mode, and heating-dominated operation mode. The heat source unit 1, relay unit 2, and load device 3 each have a cooling operation mode, a heating operation mode, and an operation-stop mode. Note that the flow of the heat transfer medium in the various operating modes in the following description is an example.

[0119] 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.

[0120] The cooling-dominated operation mode of the air conditioning apparatus 100 is an operation mode in which cooling or heating can be selected for each of multiple load devices 3, and in simultaneous cooling and heating operation in which both load devices 3 performing cooling and load devices 3 performing heating are present, the cooling load is greater than the heating load. In the cooling-dominated operation mode of the air conditioning apparatus 100, the temperature of the heat transfer medium supplied from the heat source unit 1 to the relay unit 2 is lower than the temperature of the intake air of the load devices 3 serving as indoor units, and there are one or more load devices 3 performing heating operation via the relay unit 2. The cooling load is determined, for example, by multiplying the number of indoor units performing cooling operation by the size (capacity and capacity) of the indoor units performing cooling operation. The heating load is determined, for example, by multiplying the number of indoor units performing heating operation by the size (capacity and capacity) of the indoor units performing heating operation.

[0121] The heating-dominated operation mode of the air conditioning apparatus 100 is an operation mode in which heating or cooling can be selected for each of multiple load devices 3, and in simultaneous cooling and heating operation in which load devices 3 performing cooling and load devices 3 performing heating exist simultaneously, the heating load is greater than the cooling load. In the heating-dominated operation mode of the air conditioning apparatus 100, the temperature of the heat transfer medium supplied from the heat source unit 1 to the relay unit 2 is higher than the temperature of the air sucked into the load devices 3 that are indoor units, and there are one or more load devices 3 performing cooling operation by the relay unit 2.

[0122] The operation mode of the air conditioning apparatus 100 is switched automatically by the control device 40 or switched by human operation. In the case of automatic operation by the control device 40, for example, the control device 40 sets the operation mode by observing the operating conditions in each room, such as the difference between the set temperature and the measured temperature in each room. Alternatively, the control device 40 detects the temperature of the heat transfer medium flowing through the heat transfer medium circuit 71 and compares the detected temperature with a threshold value to set the operation mode.

[0123] The control device 40 controls all operation modes of at least one heat source unit 1 to be the operation mode with the larger heat load of the overall system. The control device 40 may also control and operate at least one operation mode of multiple relay units 2 to be the operation mode with the smaller heat load of the overall system. For example, the control device 40 controls the supply water temperature of the heat source unit 1, which is an outdoor unit, to be the water temperature of the main operating side of the overall system, and controls the supply water temperature of the relay unit 2 to be the water temperature of the side that is not the main operating side of the overall system.

[0124] 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 and the third heat medium circuit 77 operate in an operation mode that results in a larger thermal load on the entire system of the air conditioning apparatus 100. The operation mode of the relay unit 2 operates in an operation mode that results in a smaller thermal load on the entire system of the air conditioning apparatus 100. 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.

[0125] 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.

[0126] In the cooling operation mode of the heat source unit 1, the heat source unit 1 generates a low-temperature heat transfer medium. The low-temperature heat transfer medium is, for example, a heat transfer medium at 10°C or below. The low-temperature heat transfer medium generated in the heat source unit 1 is sent to the relay unit 2 by the first pump 11. In the cooling operation mode of the heat source unit 1, the heat source-side heat exchanger 13 functions as a condenser, and the first intermediate heat exchanger 9 functions as an evaporator.

[0127] In the heating operation mode of the heat source unit 1, the heat source unit 1 generates a high-temperature heat transfer medium. The high-temperature heat transfer medium is, for example, a heat transfer medium at 40°C or higher. The high-temperature heat transfer medium generated in the heat source unit 1 is sent to the relay unit 2 by the first pump 11. In the heating operation mode of the heat source unit 1, the heat source-side heat exchanger 13 functions as an evaporator, and the first intermediate heat exchanger 9 functions as a condenser.

[0128] In the cooling operation mode of the relay unit 2, the relay unit 2 generates a low-temperature heat transfer medium. The low-temperature heat transfer medium is, for example, a heat transfer medium at 10°C or below. The low-temperature heat transfer medium generated in the relay unit 2 is sent to one or more of the multiple load devices 3 by the second pump 21. In the cooling operation mode of the relay unit 2, the second intermediate heat exchanger 28 functions as a condenser, and the third intermediate heat exchanger 29 functions as an evaporator.

[0129] In the heating operation mode of the relay unit 2, the relay unit 2 generates a high-temperature heat transfer medium. The high-temperature heat transfer medium is, for example, a heat transfer medium at 40°C or higher. The high-temperature heat transfer medium generated by the relay unit 2 is sent to one or more of the multiple load devices 3 by the second pump 21. In the heating operation mode of the relay unit 2, the second intermediate heat exchanger 28 functions as an evaporator, and the third intermediate heat exchanger 29 functions as a condenser.

[0130] In the operation stop mode of the relay unit 2, the operation of the second compressor 22 is stopped, and the operation of the second refrigerant circuit 20 is stopped.

[0131] In the cooling operation mode of the load device 3, heat exchange between the heat transfer medium and air is performed in the load-side heat exchanger 30, and cool air is supplied to the indoor space. In the heating operation mode of the load device 3, heat exchange between the heat transfer medium and air is performed in the load-side heat exchanger 30, and warm air is supplied to the indoor space.

[0132] 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.

[0133] (Cooling operation mode) Fig. 3 is a circuit diagram showing an example of the cooling operation mode of the air conditioning apparatus 100 according to embodiment 1. First, an example of the cooling operation mode of the air conditioning apparatus 100 will be described with reference to Fig. 3. Fig. 3 is a circuit diagram showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when cooling is performed by all of the load devices 3. Note that the dashed arrows shown in Fig. 3 indicate an example of the flow of the heat transfer medium.

[0134] 3 indicates that the valves are open, and black indicates that the valves are closed. Also, white indicates that the valves are open in the first and second flow path switching devices 61 and 62, respectively. Also, white indicates that the valves are open in the first and second opening and closing devices 81, 82, 83, 84, and 85, respectively. Also, the second connection 92 of the relay unit 2B, and the fourth connection 94, fifth connection 95, and sixth connection 96 of the relay unit 2B are sealed. The temperatures shown in FIG. 3 are merely examples and are not limited to the temperatures shown.

[0135] In the air conditioning apparatus 100 according to Embodiment 1, when the load devices 3 are operated in the cooling operation mode, the heat source unit 1 is operated in the cooling operation mode, and the relay unit 2 is in the operation stop mode. In the air conditioning apparatus 100 according to Embodiment 1, when cooling is performed in all of the load devices 3, the air conditioning apparatus 100 is operated as follows: The air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the first heat medium circuit 75 side and closes the second heat medium circuit 76 side, stops the second refrigerant circuit 20, and operates only the first refrigerant circuit 10 and the first heat medium circuit 75.

[0136] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching valve 6 and flows to the heat source side heat exchanger 13, where it exchanges heat with air and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the first expansion mechanism 7 to become a low-pressure gas-liquid two-phase refrigerant, flows to the first intermediate heat exchanger 9, and exchanges heat with the heat transfer medium flowing in the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75 to be evaporated and gasified. The gasified refrigerant passes through the first flow switching valve 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0137] The heat transfer medium flowing through the first heat medium circuit 75 is cooled by the refrigerant flowing through the first intermediate heat exchanger 9 to become a low-temperature heat transfer medium, and then flows through the relay unit 2 into the load-side heat exchanger 30 of the load device 3. The heat transfer medium that has flowed into the load-side heat exchanger 30 of the load device 3 is heated by heat exchange with the indoor air in the indoor space, and flows out of the load device 3. The heated heat transfer medium that has flowed out of the load device 3 flows through the relay unit 2 again into the first intermediate heat exchanger 9 of the heat source device 1.

[0138] (Heating operation mode) Fig. 4 is a circuit diagram showing an example of a heating operation mode in the air conditioning apparatus 100 according to embodiment 1. An example of a heating operation mode of the air conditioning apparatus 100 will be described with reference to Fig. 4. Fig. 4 is a circuit diagram showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when heating is performed by all of the load devices 3. The dashed arrows shown in Fig. 3 indicate an example of the flow of the heat transfer medium.

[0139] In addition, the white color shown in the first flow path switching device 61 and the second flow path switching device 62 in FIG. 4 indicates that the valves are open, and the black color indicates that the valves are closed. In addition, the white color shown in the first opening / closing device 81, the second opening / closing device 82, the third opening / closing device 83, the fourth opening / closing device 84, and the first flow control device 85 indicates that the valves are open, and the black color indicates that the valves are closed. In addition, the second connection portion 92 of the relay unit 2B, and the fourth connection portion 94, the fifth connection portion 95, and the sixth connection portion 96 of the relay unit 2B are sealed. In addition, the temperatures shown in FIG. 4 are merely examples and are not limited to the temperatures shown.

[0140] In the air conditioning apparatus 100 according to Embodiment 1, when the load devices 3 are operated in the heating operation mode, the heat source unit 1 is operated in the heating operation mode, and the relay unit 2 is in the operation stop mode. In the air conditioning apparatus 100 according to Embodiment 1, when heating is performed by all of the load devices 3, the air conditioning apparatus 100 is operated as follows: The air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the first heat medium circuit 75 side and closes the second heat medium circuit 76 side, stops the second refrigerant circuit 20, and operates only the first refrigerant circuit 10 and the first heat medium circuit 75.

[0141] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching valve 6 and flows into the first intermediate heat exchanger 9. The refrigerant that flows into the first intermediate heat exchanger 9 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75, and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the first expansion mechanism 7 to become a low-pressure gas-liquid two-phase refrigerant, and flows into the heat source-side heat exchanger 13. The gas-liquid two-phase refrigerant that flows into the heat source-side heat exchanger 13 exchanges heat with air and is evaporated and gasified. The gasified refrigerant passes through the first flow switching valve 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0142] The heat transfer medium flowing through the first heat medium circuit 75 is heated by the refrigerant flowing through the first intermediate heat exchanger 9 to become a high-temperature heat transfer medium, and then flows through the relay unit 2 into the load-side heat exchanger 30 of the load device 3. The heat transfer medium that has flowed into the load-side heat exchanger 30 of the load device 3 exchanges heat with the indoor air in the indoor space to be cooled, and then flows out of the load device 3. The cooled heat transfer medium that has flowed out of the load device 3 flows through the relay unit 2 again into the first intermediate heat exchanger 9 of the heat source device 1.

[0143] (Cooling-dominated operation mode) Fig. 5 is a circuit diagram showing an example of the cooling-dominated operation mode in the air conditioning apparatus 100 according to embodiment 1. Fig. 6 is a circuit diagram showing another example of the cooling-dominated operation mode in 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 Figs. 5 and 6. Figs. 5 and 6 are circuit diagrams showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when cooling and heating are performed by the load device 3 in the cooling-dominated operation mode.

[0144] 5 and 6, the white color shown in the first flow path switching device 61 and the second flow path switching device 62 indicates an open valve state, and the black color shown in the first opening / closing device 81, the second opening / closing device 82, the third opening / closing device 83, the fourth opening / closing device 84, and the first flow control device 85 indicates an open valve state, and the black color shown in the first flow path switching device 61 and the second flow path switching device 62 indicates a closed valve state. The second connection part 92 of the farthest relay device 2L, and the fourth connection part 94, the fifth connection part 95, and the sixth connection part 96 of the farthest relay device 2L are sealed.

[0145] 5 shows an air conditioning apparatus 100 in which the load device 3 connected to the upstream relay unit 2A in the flow direction of the heat transfer medium sent out from the heat source unit 1 is a cooling device, and the load device 3 connected to the downstream relay unit 2B is a heating device. Also, Fig. 6 shows an air conditioning apparatus 100 in which the load device 3 connected to the upstream relay unit 2A in the flow direction of the heat transfer medium sent out from the heat source unit 1 is a heating device, and the load device 3 connected to the downstream relay unit 2B is a cooling device. With reference to Figs. 5 and 6, a case will be described in which one load device 3 performs cooling and the other load device 3 performs heating, and cooling-dominated operation with a heavy cooling load is performed.

[0146] When the air conditioning apparatus 100 according to Embodiment 1 operates in the cooling-dominant operation mode, the heat source unit 1 operates in the cooling operation mode, and one or more relay units 2 operate in the heating operation mode. Relay units 2 that do not operate in the heating operation mode are in an operation stop state.

[0147] When the air conditioning apparatus 100 performs cooling on the load device 3 connected to one relay unit 2 and heating on the load device 3 connected to the other relay unit 2, the air conditioning apparatus 100 operates the first refrigerant circuit 10, the first heat medium circuit 75, the second refrigerant circuit 20, the second heat medium circuit 76, and the third heat medium circuit 77. To connect the load-side heat exchanger 30 of the load device 3 performing cooling to the first heat medium circuit 75, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the first heat medium circuit 75 side and closes the second heat medium circuit 76 side. To connect the load-side heat exchanger 30 of the load device 3 performing heating to the second heat medium circuit 76, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the second heat medium circuit 76 side and closes the first heat medium circuit 75 side.

[0148] The third heat medium circuit 77 includes the first heat medium circuit 75. Therefore, in order to connect the load-side heat exchanger 30 of the load device 3 that performs cooling to the third heat medium circuit 77, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the third heat medium circuit 77 side and closes the second heat medium circuit 76 side. In addition, in order to connect the load-side heat exchanger 30 of the load device 3 that performs heating to the second heat medium circuit 76, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the second heat medium circuit 76 side and closes the third heat medium circuit 77 side.

[0149] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching valve 6 and flows to the heat source side heat exchanger 13, where it exchanges heat with air and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the first expansion mechanism 7 to become a low-pressure gas-liquid two-phase refrigerant, flows to the first intermediate heat exchanger 9, and exchanges heat with the heat transfer medium flowing in the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75, the third heat medium circuit 77, etc., to be evaporated and gasified. The gasified refrigerant passes through the first flow switching valve 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0150] The heat transfer medium flowing through the heat transfer medium circuit 71 constituting the first heat medium circuit 75 etc. is cooled by the refrigerant flowing through the first intermediate heat exchanger 9 to become a low-temperature heat transfer medium, and then passes through the relay unit 2 to which the load device 3 to be cooled is connected 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 in the indoor space, is heated, and flows out of the load device 3.

[0151] The heated heat transfer medium that flows out of the load device 3 flows into the second intermediate heat exchanger 28 of the relay unit 2 to which the load device 3 to be heated is connected, via the heat accommodation piping 73 or the return piping 74. The heat transfer medium that flows into the second intermediate heat exchanger 28 of the relay unit 2 to which the load device 3 to be heated is connected is cooled by heat exchange with the refrigerant circulating in the second refrigerant circuit 20, passes through the return piping 74, and then flows again into the first intermediate heat exchanger 9 of the heat source unit 1.

[0152] In the second refrigerant circuit 20 of the relay unit 2 to which the load device 3 to be heated is connected, high-temperature, high-pressure gas refrigerant discharged from the second compressor 22 passes through the second flow switching valve 26 and flows into the third intermediate heat exchanger 29. The refrigerant that flows into the third intermediate heat exchanger 29 exchanges heat with the heat transfer medium flowing through the second heat medium circuit 76 and condenses and liquefies. The condensed and liquefied refrigerant is decompressed by the second expansion mechanism 27 to become a low-pressure gas-liquid two-phase refrigerant and flows into the second intermediate heat exchanger 28. The gas-liquid two-phase refrigerant that flows into the second intermediate heat exchanger 28 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75 and the like and evaporates and gasifies. The gasified refrigerant passes through the second flow switching valve 26 and is drawn into the second compressor 22 via an accumulator (not shown).

[0153] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2 connected to the load device 3 to be heated is heated by the refrigerant flowing through the third intermediate heat exchanger 29 to become a high-temperature heat transfer medium, and then flows into the load-side heat exchanger 30 of the load device 3 connected to the relay unit 2. 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 in the indoor space 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 third intermediate heat exchanger 29 of the relay unit 2.

[0154] (Heating-dominated operation mode) Fig. 7 is a circuit diagram showing an example of a heating-dominated operation mode in the air conditioning apparatus 100 according to embodiment 1. Fig. 8 is a circuit diagram showing another example of a heating-dominated operation mode in the air conditioning apparatus 100 according to embodiment 1. An example of a heating-dominated operation mode of the air conditioning apparatus 100 will be described with reference to Figs. 7 and 8. Figs. 7 and 8 are circuit diagrams showing the flow of the heat transfer medium in the air conditioning apparatus 100 according to embodiment 1 when cooling and heating are performed by the load device 3 in the heating-dominated operation mode.

[0155] 7 and 8, the white color shown in the first flow path switching device 61 and the second flow path switching device 62 indicates an open valve state, and the black color shown in the first opening / closing device 81, the second opening / closing device 82, the third opening / closing device 83, the fourth opening / closing device 84, and the first flow control device 85 indicates an open valve state, and the black color shown in the first opening / closing device 6 ...2, the third opening / closing device 83, the fourth opening / closing device 84, and the first flow control device 85 indicates an open valve state. The second connection part 92 of the farthest repeater 2L, and the fourth connection part 94, the fifth connection part 95, and the sixth connection part 96 of the farthest repeater 2L are sealed.

[0156] 7 shows an air conditioning apparatus 100 in which the load device 3 connected to the upstream relay unit 2A in the flow direction of the heat transfer medium sent out from the heat source unit 1 is a cooling device, and the load device 3 connected to the downstream relay unit 2B is a heating device. Also, FIG. 8 shows an air conditioning apparatus 100 in which the load device 3 connected to the upstream relay unit 2A in the flow direction of the heat transfer medium sent out from the heat source unit 1 is a heating device, and the load device 3 connected to the downstream relay unit 2B is a cooling device. With reference to FIGS. 7 and 8, a case will be described in which one load device 3 performs cooling and the other load device 3 performs heating, and heating-dominated operation is performed with a large heating load.

[0157] When the air conditioning apparatus 100 according to Embodiment 1 operates in the heating-dominant operation mode, the heat source unit 1 operates in the heating operation mode, and one or more relay units 2 operate in the cooling operation mode. Relay units 2 that do not operate in the cooling operation mode are in an operation stop state.

[0158] When the air conditioning apparatus 100 performs cooling on the load device 3 connected to one relay unit 2 and heating on the load device 3 connected to the other relay unit 2, it operates the first refrigerant circuit 10, the first heat medium circuit 75, the second refrigerant circuit 20, the second heat medium circuit 76, and the third heat medium circuit 77. To connect the load-side heat exchanger 30 of the load device 3 performing cooling to the second heat medium circuit 76, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the second heat medium circuit 76 side and closes the first heat medium circuit 75 side. To connect the load-side heat exchanger 30 of the load device 3 performing heating to the first heat medium circuit 75, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the first heat medium circuit 75 side and closes the second heat medium circuit 76 side.

[0159] The third heat medium circuit 77 includes the first heat medium circuit 75. Therefore, in order to connect the load-side heat exchanger 30 of the load device 3 that performs cooling to the second heat medium circuit 76, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the second heat medium circuit 76 side and closes the third heat medium circuit 77 side. In addition, in order to connect the load-side heat exchanger 30 of the load device 3 that performs heating to the third heat medium circuit 77, the air conditioning apparatus 100 opens the first flow switching device 61 and the second flow switching device 62 to the third heat medium circuit 77 side and closes the second heat medium circuit 76 side.

[0160] In the first refrigerant circuit 10, high-temperature, high-pressure gas refrigerant discharged from the first compressor 12 passes through the first flow switching valve 6 and flows into the first intermediate heat exchanger 9. The refrigerant that flows into the first intermediate heat exchanger 9 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75, the third heat medium circuit 77, etc., and is condensed and liquefied. The condensed and liquefied refrigerant is reduced in pressure by the first expansion mechanism 7 to become a low-pressure two-phase gas-liquid refrigerant and flows into the heat source-side heat exchanger 13. The two-phase gas-liquid refrigerant that flows into the heat source-side heat exchanger 13 exchanges heat with air and is evaporated and gasified. The gasified refrigerant passes through the first flow switching valve 6 and is drawn into the first compressor 12 via an accumulator (not shown).

[0161] The heat transfer medium flowing through the heat transfer medium circuit 71 constituting the first heat medium circuit 75 etc. is heated by the refrigerant flowing through the first intermediate heat exchanger 9 to become a high-temperature heat transfer medium, and then passes through the relay unit 2 to which the load device 3 to be heated is connected, 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 in the indoor space, is cooled, and flows out of the load device 3.

[0162] The cooled heat transfer medium that flows out of the load device 3 flows into the second intermediate heat exchanger 28 of the relay unit 2 to which the load device 3 to be cooled is connected, via the heat accommodation piping 73 or the return piping 74. The heat transfer medium that flows into the second intermediate heat exchanger 28 of the relay unit 2 to which the load device 3 to be cooled is connected is heated by heat exchange with the refrigerant circulating in the second refrigerant circuit 20, passes through the return piping 74, and then flows again into the first intermediate heat exchanger 9 of the heat source unit 1.

[0163] In the second refrigerant circuit 20 of the relay unit 2 to which the load device 3 to be cooled is connected, high-temperature, high-pressure gas refrigerant discharged from the second compressor 22 passes through the second flow switching valve 26 and flows into the second intermediate heat exchanger 28. The refrigerant that flows into the second intermediate heat exchanger 28 exchanges heat with the heat transfer medium flowing through the heat transfer medium circuit 71 that constitutes the first heat medium circuit 75 and the like, and is condensed and liquefied. The condensed and liquefied refrigerant is decompressed by the second expansion mechanism 27 to become a low-pressure gas-liquid two-phase refrigerant, and flows into the third intermediate heat exchanger 29. The gas-liquid two-phase refrigerant that flows into the third intermediate heat exchanger 29 exchanges heat with the heat transfer medium flowing through the second heat medium circuit 76, and is evaporated and gasified. The gasified refrigerant passes through the second flow switching valve 26 and is drawn into the second compressor 22 via an accumulator (not shown).

[0164] The heat transfer medium flowing through the second heat medium circuit 76 of the relay unit 2 connected to the load device 3 to be cooled is cooled by the refrigerant flowing through the third intermediate heat exchanger 29 to become a low-temperature heat transfer medium, and then flows into the load-side heat exchanger 30 of the load device 3 connected to the relay unit 2. 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 in the indoor space, where it is heated, 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 third intermediate heat exchanger 29 of the relay unit 2.

[0165] Fig. 9 is a schematic diagram of another example of the configuration of the air conditioning apparatus 100 according to embodiment 1. While Fig. 1 shows an example in which there are two relay units 2, the number of relay units 2 is not limited to two, and there may be three or more relay units, such as relay unit 2A, relay unit 2B, and relay unit 2C shown in Fig. 9. The air conditioning apparatus 100 according to embodiment 1 has multiple relay units 2.

[0166] Furthermore, the numbers of heat source units 1 and load devices 3 are not limited to those described above. Two or more heat source units 1 may be installed. When multiple heat source units 1 are installed, the heat source units 1 are connected to each other via the first heat medium pipes 70A. Furthermore, three or more load devices 3 connected to each relay unit 2 may be installed. In this case, all of the load devices 3 may be indoor units, or some or all of the load devices 3 may be hot water storage tanks for supplying hot water. Furthermore, the air conditioning apparatus 100 may include a configuration in which some of the load devices 3 are connected directly to the heat source units 1 without going through the relay units 2.

[0167] In the air conditioning apparatus 100, when the load device 3 is a hot water storage tank, the heat transfer medium flowing through the heat transfer medium circuit 71 is water supplied to the hot water storage tank, which is the load device 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 unit 1, the relay unit 2, or the relay unit 2. When the load device 3 is a hot water storage tank, hot water is stored in an operating mode similar to the heating operation mode in the load device 3 described above, as an example.

[0168] [Operation and Effect of Air Conditioning Apparatus 100] The air conditioning apparatus 100 comprises a heat source unit 1, a plurality of relay units 2 connected in series to the heat source unit 1 via piping connections, and a plurality of load devices 3 connected to each of the plurality of relay units 2. The air conditioning apparatus 100 also comprises a plurality of heat medium pipes 70 connecting the heat source unit 1, the plurality of relay units 2, and the plurality of load devices 3. The heat source unit 1 comprises a first refrigerant circuit 10 through which a refrigerant circulates, and the first refrigerant circuit 10 has a first intermediate heat exchanger 9 that exchanges heat between the refrigerant flowing through the first refrigerant circuit 10 and a heat transfer medium flowing therein, and a heat source-side heat exchanger 13 that exchanges heat between the refrigerant flowing through the first refrigerant circuit 10 and air.

[0169] Each of the multiple relay units 2 includes a second refrigerant circuit 20 through which a refrigerant circulates. The second refrigerant circuit 20 has a second intermediate heat exchanger 28 through which the refrigerant flowing through the second refrigerant circuit 20 exchanges heat with a heat transfer medium flowing therethrough, and a third intermediate heat exchanger 29 through which the refrigerant flowing through the second refrigerant circuit 20 exchanges heat with the heat transfer medium flowing therethrough. The first intermediate heat exchanger 9, the second intermediate heat exchanger 28, and the load-side heat exchangers 30 of the multiple load devices 3 are connected by multiple heat medium pipes 70 to form a first heat medium circuit 75 through which the heat transfer medium circulates.

[0170] The plurality of heat medium pipes 70 include two first heat medium pipes 70A connecting the heat source unit 1 and one of the plurality of relay units 2, and three second heat medium pipes 70B connecting the plurality of relay units 2. The plurality of heat medium pipes 70 also include two third heat medium pipes 70C connecting each of the plurality of relay units 2 and each of the plurality of load devices 3.

[0171] Therefore, when cooling and heating are performed simultaneously by multiple load devices 3, the air conditioning apparatus 100 according to Embodiment 1 can perform cooling or heating using the first refrigerant circuit 10 provided in the heat source unit 1 and the second refrigerant circuit 20 provided in the relay unit 2. Therefore, the air conditioning apparatus 100 can reduce the number of pipes connecting the heat source unit 1 and the relay unit 2 to two, which reduces the number of pipes required and reduces the burden of piping work.

[0172] Furthermore, the air conditioning apparatus 100 according to embodiment 1 connects the heat source apparatus 1 and the relay unit 2, and the relay unit 2 and the load device 3, respectively, with two pipes, and the relay units are connected to each other with three pipes. Through these pipes, the air conditioning apparatus 100 can utilize heat generated by a load device 3 connected to one relay unit 2 as a heat source for cooling or heating a load device 3 connected to another relay unit 2, thereby realizing heat interchange between multiple relay units 2. That is, by utilizing these pipes, the air conditioning apparatus 100 can reuse heat recovered from the cooling operation of one relay unit 2 during simultaneous cooling and heating operation between relay units 2 for heating the other relay unit 2. Alternatively, by utilizing these pipes, the air conditioning apparatus 100 can reuse heat recovered from the heating operation of one relay unit 2 during simultaneous cooling and heating operation between relay units 2 for cooling the other relay unit 2. Therefore, the air conditioning apparatus 100 can achieve improved energy efficiency compared to an air conditioning apparatus without these pipes.

[0173] Furthermore, in the air conditioning apparatus 100, the third intermediate heat exchanger 29 and the load side heat exchanger 30 are connected by a third heat medium pipe 70C to form a second heat medium circuit 76 through which a heat transfer medium circulates. The first heat medium circuit 75 and the second heat medium circuit 76 are provided with a first flow path switching device 61 and a second flow path switching device 62 that switch the flow path of the heat transfer medium flowing into the load side heat exchanger 30 to either the first heat medium circuit 75 or the second heat medium circuit 76. Therefore, the air conditioning apparatus 100 generates chilled or hot water using the heat source unit 1 and the relay unit 2, and can achieve simultaneous cooling and heating operation by switching between the circuit for the chilled or hot water generated by the heat source unit 1 and the circuit for the chilled or hot water generated by the relay unit 2.

[0174] The air conditioning apparatus 100 also has a second heat medium piping 70B. The second heat medium piping 70B includes an outgoing piping 72 through which the heat transfer medium supplied from the heat source unit 1 to the multiple relay units 2 flows, and a heat accommodation piping 73 through which the heat transfer medium flows from the nearest relay unit 2F toward the farthest relay unit 2L. The second heat medium piping 70B also includes a return piping 74 through which the heat transfer medium flowing out from the farthest relay unit 2L flows toward the heat source unit 1. When the air conditioning apparatus 100 is connected to multiple relay units 2, the relay units 2 are connected to each other via the outgoing piping 72, the heat accommodation piping 73, and the return piping 74.

[0175] Through these pipes, the air conditioning apparatus 100 can transport heat via the heat transport medium from the upstream relay unit 2 to the downstream relay unit 2 in the flow direction of the heat transport medium sent out from the heat source unit 1. Therefore, through these pipes, the air conditioning apparatus 100 can utilize heat generated by a load device 3 connected to one relay unit 2 as a heat source for cooling or heating the load device 3 connected to the other relay unit 2, thereby enabling highly energy-efficient operation.

[0176] The air conditioning apparatus 100 has a first heat medium circuit 75 and a second heat medium circuit 76. The first heat medium circuit 75 includes a circuit configured by sequentially connecting with piping a first intermediate heat exchanger 9, a supply pipe 72, a first flow switching device 61, a load side heat exchanger 30, a second flow switching device 62, a second intermediate heat exchanger 28, a heat accommodation pipe 73, and a return pipe 74. The second heat medium circuit 76 includes a circuit configured by sequentially connecting with piping a third intermediate heat exchanger 29, the first flow switching device 61, the load side heat exchanger 30, and the second flow switching device 62. Therefore, the air conditioning apparatus 100 generates chilled and hot water using the heat source unit 1 and the relay unit 2, and can achieve simultaneous cooling and heating operation by switching between the first heat medium circuit 75 connected to the heat source unit 1 and the second heat medium circuit 76 connected to the third intermediate heat exchanger 29 of the relay unit 2.

[0177] Furthermore, each of the multiple relay units 2 has a first opening and closing device 81 provided on an internal pipe connecting an outlet side portion of the second intermediate heat exchanger 28 and an internal pipe connected to the heat accommodation pipe 73. Each of the multiple relay units 2 has a first relay unit pipe 46A connecting an internal pipe connected to the return pipe 74 and an internal pipe on the inlet side of the second intermediate heat exchanger 28, and a second opening and closing device 82 provided on the first relay unit pipe 46A. Each of the multiple relay units 2 has an internal pipe connecting the second intermediate heat exchanger 28 and the first opening and closing device 81, and a second relay unit pipe 48A connecting an internal pipe connected to the return pipe 74 and an internal pipe downstream of the connection portion of the first relay unit pipe 46A. Each of the multiple relay units 2 has a third opening and closing device 83 provided on the second relay unit pipe 48A.

[0178] By using these opening and closing devices, the air conditioning apparatus 100 can switch between a circuit in which the heat transfer medium flows through the supply pipe 72, the heat accommodation pipe 73, and the return pipe 74 in this order, and a circuit in which the heat transfer medium flows through the supply pipe 72, the upstream side of the return pipe 74, and the downstream side of the return pipe 74 in this order. In other words, by using these opening and closing devices, the air conditioning apparatus 100 can switch the inflow source of the heat transfer medium flowing into the second intermediate heat exchanger 28 depending on the operating state of the load device 3.

[0179] Furthermore, each of the multiple relay units 2 has a first flow control device 85 that adjusts the flow rate of the heat transfer medium flowing through the return pipe 74, in the internal pipe between the connection portion of the first relay pipe 46A and the connection portion of the second relay pipe 48A on the internal pipe connected to the return pipe 74. Here, we consider a case in which the air conditioning apparatus 100 flows the heat transfer medium from the upstream side of the internal pipe connected to the return pipe 74 through the first relay pipe 46A, the second intermediate heat exchanger 28, and the second relay pipe 48A to the downstream side of the internal pipe. In such a case, the air conditioning apparatus 100 can adjust the flow rate of the heat transfer medium flowing to the second intermediate heat exchanger 28 by having the first flow control device 85.

[0180] The air conditioning apparatus 100 is formed with a third heat medium circuit 77 that partially includes the first heat medium circuit 75. In the third heat medium circuit 77, the heat transfer medium sequentially flows through the first intermediate heat exchanger 9, the supply pipe 72, the first flow switching device 61 of at least one relay unit 2 among the multiple relay units 2, the load side heat exchanger 30, the second flow switching device 62, the second intermediate heat exchanger 28, and the heat accommodation pipe 73. In the third heat medium circuit 77, the heat transfer medium flows through the heat accommodation pipe 73, and then sequentially flows through the first relay unit pipe 46A, the second intermediate heat exchanger 28, the second relay unit pipe 48A, and the return pipe 74 of at least one other relay unit 2 among the multiple relay units 2. In the third heat medium circuit 77, the heat transfer medium then passes through at least one relay unit 2 among the multiple relay units 2 and returns to the first intermediate heat exchanger 9 of the heat source unit 1.

[0181] The air conditioning apparatus 100 can transport heat via the heat transport medium from the upstream relay unit 2 to the downstream relay unit 2 in the flow direction of the heat transport medium sent from the heat source unit 1 using the third heat medium circuit 77. Therefore, these piping allows the air conditioning apparatus 100 to utilize heat generated in a load device 3 connected to one relay unit 2 as a heat source for cooling or heating in a load device 3 connected to the other relay unit 2, thereby enabling highly energy-efficient operation. For example, by having the third heat medium circuit 77, the air conditioning apparatus 100 can reuse, in another relay unit 2, the heat of the heat transport medium that has been heated by cooling in a load device 3 during simultaneous cooling and heating operation.

[0182] Embodiment 2. Figure 10 is a circuit diagram that shows a schematic diagram 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 10. 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.

[0183] The air conditioning apparatus 100 according to Embodiment 2 differs from the air conditioning apparatus 100 according to Embodiment 1 in that it has a pump 33. The relay unit 2 of the air conditioning apparatus 100 according to Embodiment 2 has a pump provided in the first relay unit piping 46A that draws the heat transfer medium from an internal piping connected to the return piping 74 into the first relay unit piping 46A and forms a flow of the heat transfer medium flowing inside the first relay unit piping 46A.

[0184] By operation of the pump 33, the heat transfer medium drawn from the third flow path 43 flows into the second intermediate heat exchanger 28 via the fifth flow path 45. The heat transfer medium that has flowed into the second intermediate heat exchanger 28 exchanges heat with the refrigerant in the second refrigerant circuit 20, flows into the third flow path 43 via the seventh flow path 47 and the eighth flow path 48, and flows into the first intermediate heat exchanger 9 of the heat source unit 1 via the return pipe 74.

[0185] The pump 33 is one of the devices constituting the first heat medium circuit 75 or the third heat medium circuit 77. The pump 33 sucks the heat transfer medium in the first heat medium circuit 75 or the third heat medium circuit 77, applies pressure to it, and sends it out to circulate. The capacity of the pump 33 is changed by a pump inverter drive device (not shown). The pump inverter drive device changes the capacity of the pump 33 by arbitrarily changing the drive frequency based on instructions from the control device 40.

[0186] [Operation and Effect of the Air Conditioning Apparatus 100] The multiple relay units 2 are provided with a pump 33 in the first relay unit piping 46A that draws a heat transfer medium from an internal pipe connected to the return pipe 74 into the first relay unit piping 46A and forms a flow of the heat transfer medium flowing inside the first relay unit piping 46A. Here, we consider a case in which the air conditioning apparatus 100 flows the heat transfer medium from the upstream side of the internal pipe connected to the return pipe 74 to the downstream side of the internal pipe via the first relay unit piping 46A, the second intermediate heat exchanger 28, and the second relay unit piping 48A. In such a case, the air conditioning apparatus 100 has the pump 33, which makes it easier to draw the heat transfer medium into the second intermediate heat exchanger 28 compared to an air conditioning apparatus 100 not having the pump 33, and makes it possible to adjust the flow rate of the heat transfer medium flowing through the second intermediate heat exchanger 28.

[0187] Although the air conditioning device 100 has been described above based on the embodiment, the air conditioning device 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 device 100 described above is an example, and other components may be included, or some components may be omitted. In short, the air conditioning device 100 includes a range of design modifications and application variations that are normally made by a person skilled in the art, as long as they do not deviate from the technical concept of the air conditioning device 100.

[0188] 1 Heat source unit, 2 Relay unit, 2A Relay unit, 2B Relay unit, 2C Relay unit, 2F Nearest relay unit, 2L Farthest relay unit, 3 Load device, 3A Load device, 3B Load device, 6 First flow path switching valve, 7 First expansion mechanism, 8 Heat source side blower, 9 First intermediate heat exchanger, 10 First refrigerant circuit, 11 First pump, 12 First compressor, 13 Heat source side heat exchanger, 20 Second refrigerant circuit, 21 Second pump, 22 Second compressor, 26 Second flow path switching valve, 27 Second expansion mechanism, 28 Second intermediate heat exchanger, 29 Third intermediate heat exchanger, 29a First inlet / outlet, 29b Second inlet / outlet, 30 Load side heat exchanger, 31 Load side blower, 33 Pump, 40 Control device, 41 First flow path, 42 Second flow path, 43 Third flow path, 44 Fourth flow path, 45 Fifth flow path, 46 Sixth flow path, 46A First relay unit piping, 47 Seventh flow path, 48 Eighth flow path, 48A Second relay unit piping, 49 Ninth flow path, 51 Tenth flow path, 52 Eleventh flow path, 61 First flow path switching device, 61a First flow path switching device, 61b First flow path switching device, 61c First flow path switching device, 62 Second flow path switching device, 62a Second flow path switching device, 62b Second flow path switching device, 62c Second flow path switching device, 70 Heat medium piping, 70A First heat medium piping, 70B Second heat medium piping, 70C Third heat medium piping, 71 Heat transfer medium circuit, 72 Outward piping, 73 Heat accommodation piping, 74 Return piping, 75 First heat medium circuit, 76 Second heat medium circuit, 77 Third heat medium circuit, 81 First opening and closing device, 82 Second opening and closing device, 83 Third opening and closing device, 84 Fourth opening and closing device, 85 First flow control device, 91: First connection portion, 92: Second connection portion, 93: Third connection portion, 94: Fourth connection portion, 95: Fifth connection portion, 96: Sixth connection portion, 100: Air conditioning device, 120: Main body portion, 190: Load device side connection portion, 191: Load device side first connection portion, 192: Load device side second connection portion, 193: Load device side third connection portion, 194: Load device side fourth connection portion, 200: Building.

Claims

1. Heat source unit, Multiple relay units connected in series to the aforementioned heat source unit via piping connections, Multiple load devices connected to each of the aforementioned multiple relay devices, Multiple heat transfer fluid pipes connecting the heat source unit, the multiple relay units, and the multiple load devices, Equipped with, The aforementioned heat source unit is The system includes a first refrigerant circuit through which a refrigerant circulates, the first refrigerant circuit comprising a first intermediate heat exchanger in which the refrigerant flowing through the first refrigerant circuit and a heat transfer medium flowing inside exchange heat, and a heat source side heat exchanger in which the refrigerant flowing through the first refrigerant circuit and air exchange heat. Each of the aforementioned relay devices is The system includes a second refrigerant circuit through which a refrigerant circulates, the second refrigerant circuit comprising a second intermediate heat exchanger through which the refrigerant flowing through the second refrigerant circuit and a heat transfer medium flowing inside exchange heat, and a third intermediate heat exchanger through which the refrigerant flowing through the second refrigerant circuit and a heat transfer medium flowing inside exchange heat. The first intermediate heat exchanger, the second intermediate heat exchanger, and the load-side heat exchangers of the plurality of load devices are connected by the plurality of heat transfer medium pipes, forming a first heat transfer medium circuit through which the heat transfer medium circulates. The plurality of heat transfer pipes, Two first heat transfer fluid pipes connecting the heat source unit and one of the multiple relay units, Three second heat transfer fluid pipes connecting the aforementioned multiple relay units, Two third heat transfer fluid pipes connecting each of the multiple relay units and each of the multiple load devices, Air conditioning system including

2. The third intermediate heat exchanger and the load-side heat exchanger are connected by the third heat transfer medium piping, forming a second heat transfer medium circuit through which the heat transfer medium circulates. The first heat transfer fluid circuit and the second heat transfer fluid circuit include: The air conditioning system according to claim 1, further comprising a first flow path switching device and a second flow path switching device for switching the flow path of the heat transfer medium flowing into the load-side heat exchanger to the first heat transfer medium circuit or the second heat transfer medium circuit.

3. When, among the multiple relays connected in series, the relay connected to the heat source is designated as the nearest relay, and the relay connected to the position furthest from the heat source is designated as the furthest relay, The second heat transfer fluid piping is A supply pipe through which the heat transfer medium supplied from the heat source to the multiple relay units flows, A heat transfer piping through which a heat transfer medium flows from the nearest relay unit to the furthest relay unit, A return pipe through which the heat transfer medium discharged from the furthest relay unit flows toward the heat source unit, An air conditioning device according to claim 2, including the following:

4. The first heat transfer circuit is The circuit includes the first intermediate heat exchanger, the supply piping, the first flow path switching device, the load-side heat exchanger, the second flow path switching device, the second intermediate heat exchanger, the heat exchange piping, and the return piping, all connected sequentially by piping. The second heat transfer circuit is, The air conditioning system according to claim 3, which includes a circuit configured by sequentially connecting the third intermediate heat exchanger, the first flow path switching device, the load-side heat exchanger, and the second flow path switching device with piping.

5. Each of the aforementioned relay devices is A first switchgear is provided on the internal piping that connects the outlet portion of the second intermediate heat exchanger to the internal piping connected to the heat exchange piping, A first relay piping connects the internal piping connected to the return piping and the internal piping on the inlet side of the second intermediate heat exchanger, The second switchgear provided in the first relay piping, Internal piping connecting the second intermediate heat exchanger and the first switchgear, and second relay piping connecting internal piping downstream of the connection point of the first relay piping on the internal piping connected to the return piping, The third switchgear installed in the second relay piping, An air conditioning device according to claim 4, having the following features.

6. Each of the aforementioned relay devices is The air conditioning device according to claim 5, further comprising a first flow rate adjustment device for adjusting the flow rate of the heat transport medium flowing through the return piping, in the internal piping between the connection portion of the first relay piping and the connection portion of the second relay piping on the internal piping connected to the return piping.

7. An air conditioning system according to claim 5 or 6, wherein a third heat transfer medium circuit is formed, which includes the first heat transfer medium circuit in part, wherein the heat transfer medium flows sequentially through the first intermediate heat exchanger, the supply piping, the first flow path switching device of at least one of the plurality of relays, the load-side heat exchanger, the second flow path switching device, the second intermediate heat exchanger, the heat transfer piping, the piping of at least one other first relay among the plurality of relays, the second intermediate heat exchanger, the second relay piping, and the return piping, and returns to the first intermediate heat exchanger after passing through at least one of the plurality of relays.

8. The aforementioned multiple relay devices The air conditioning system according to claim 5 or 6, wherein the first relay piping is provided with a pump that draws a heat transfer medium from an internal pipe connected to the return piping into the first relay piping and forms a flow of the heat transfer medium flowing inside the first relay piping.