WO2025057396A1 - Air conditioner - Google Patents

Abstract

In an air conditioner, a compressor, a main refrigerant flow path switching device, a heat source-side heat exchanger, an on-off valve, a first throttle device, a refrigerant flow path of an inter-first refrigerant heat medium heat exchanger, and a first refrigerant flow path switching device are connected by refrigerant piping. A second throttle device, a refrigerant flow path of an inter-second refrigerant heat medium heat exchanger, and a second refrigerant flow path switching device are connected by the refrigerant piping in parallel with the first throttle device, the refrigerant flow path of the inter-first refrigerant heat medium heat exchanger, and the first refrigerant flow path switching device. The air conditioner includes a heat source machine that has a refrigerant circuit in which a refrigerant circulates, a part of a first heat medium circuit where a first pump and a heat medium flow path of the inter-first refrigerant heat medium heat exchanger are connected by first heat medium piping and a first heat medium circulates, and a part of a second heat medium circuit where a second pump and a heat medium flow path of the inter-second refrigerant heat medium heat exchanger are connected by second heat medium piping and a second heat medium circulates. The air conditioner also includes a plurality of indoor units each having a load-side heat exchanger, and a relay device connected between the heat source machine and the plurality of indoor units. The relay device is connected to each of the plurality of indoor units by indoor-side outgoing heat medium piping and indoor-side return heat medium piping, and a heat medium supplied to each of the plurality of indoor units is switched between the first heat medium and the second heat medium via indoor-side outgoing heat medium piping and indoor-side return heat medium piping. The first heat medium piping has first outgoing heat medium piping and first return heat medium piping that connect the heat source machine and the relay device, and the second heat medium piping has second outgoing heat medium piping and second return heat medium piping that connect the heat source machine and the relay device.

Description

Air Conditioning Equipment

This disclosure relates to air conditioning devices.

　Conventionally, there has been an air conditioner that connects the heat source unit and the relay unit, and the relay unit and the indoor unit, with two pipes each, supplies two-phase refrigerant in liquid and gaseous states from the heat source unit to the relay unit through one pipe (main pipe), separates the refrigerant into gaseous and liquid refrigerant in a gas-liquid separator inside the relay unit, and then switches the refrigerant supplied to the indoor unit to switch between cooling and heating (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 4-110573

In Patent Document 1, because refrigerant flows through the piping connecting the heat source unit and the relay unit, and through the piping connecting the relay unit and the indoor unit, it is necessary to increase the amount of refrigerant in the refrigerant circuit depending on the length of the piping, which poses the problem of an increased amount of refrigerant required in the refrigerant circuit. Also, while heat source units are generally installed outdoors, relay units and indoor units are installed indoors, which means that the refrigerant flows indoors, creating a risk of refrigerant leaking indoors.

This disclosure has been made to solve the problems described above, and aims to provide an air conditioner that reduces the amount of refrigerant required in the refrigerant circuit while reducing the risk of refrigerant leaking indoors.

The air conditioning apparatus according to the present disclosure comprises a compressor, a main refrigerant flow switching device, a heat source side heat exchanger, an on-off valve, a first throttling device, a refrigerant flow path of a first refrigerant-intermediate heat exchanger, and a first refrigerant flow switching device, which are connected by refrigerant piping, and a second throttling device, a refrigerant flow path of a second refrigerant-intermediate heat exchanger, and a second refrigerant flow switching device, which are connected in parallel to the first throttling device, the refrigerant flow path of the first refrigerant-intermediate heat exchanger, and the first refrigerant flow switching device by the refrigerant piping, a refrigerant circuit in which a refrigerant circulates, a first pump and a heat medium flow path of the first refrigerant-intermediate heat exchanger are connected by a first heat medium piping, a part of the first heat medium circuit in which the first heat medium circulates, and a second pump and a heat medium flow path of the second refrigerant-intermediate heat exchanger are connected by a second heat medium piping, and a second heat medium circuit in which a second heat medium circulates. A heat source unit having a part of a circuit, a plurality of indoor units having a load side heat exchanger, and a relay unit connected between the heat source unit and the plurality of indoor units, the relay unit is connected to each of the plurality of indoor units by an indoor side forward heat medium piping and an indoor side return heat medium piping, and switches the heat medium supplied to each of the plurality of indoor units via the indoor side forward heat medium piping and the indoor side return heat medium piping between the first heat medium and the second heat medium, the first heat medium piping has a first forward heat medium piping and a first return heat medium piping that connect the heat source unit and the relay unit, and the second heat medium piping has a second forward heat medium piping and a second return heat medium piping that connect the heat source unit and the relay unit.

In the air conditioning device according to the present disclosure, the refrigerant circuit in which the refrigerant circulates is provided in the heat source unit, the heat source unit and the relay unit are connected by a first forward heat medium pipe and a first return heat medium pipe through which the first heat medium flows, and a second forward heat medium pipe and a second return heat medium pipe through which the second heat medium flows, and the relay unit and each of the indoor units are connected by an indoor forward heat medium pipe and an indoor return heat medium pipe through which the first heat medium or the second heat medium flows. In other words, refrigerant does not flow through the pipes connecting the heat source unit and the relay unit, and the pipes connecting the relay unit and the indoor units, and the flow of refrigerant can be closed inside the heat source unit, which is generally installed outdoors, so that the amount of refrigerant required in the refrigerant circuit can be reduced. In addition, refrigerant does not flow through the relay unit and the indoor units, which are generally installed indoors, so that the risk of refrigerant leakage indoors can be reduced.

1 is a schematic diagram showing an example of installation of an air conditioning apparatus according to a first embodiment. 1 is a schematic diagram showing a circuit configuration of an air conditioning apparatus according to a first embodiment. FIG. 4 is a schematic diagram showing a circuit configuration of a modified example of the air conditioning apparatus according to the first embodiment. 2 is a refrigerant circuit diagram showing the flow of refrigerant during full cooling operation of the air conditioning apparatus according to the first embodiment. FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant during full heating operation of the air conditioning apparatus according to the first embodiment. FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant during cooling-dominant operation of the air-conditioning apparatus according to the first embodiment. FIG. 2 is a refrigerant circuit diagram showing the flow of refrigerant during heating-dominant operation of the air-conditioning apparatus according to the first embodiment. FIG. 11 is a schematic diagram showing a circuit configuration on the heat source unit side of an air conditioning apparatus according to embodiment 2. FIG.

Below, an embodiment of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiment described below. Also, the size relationships of the components in the drawings may differ from the actual ones.

Embodiment 1.
FIG. 1 is a schematic diagram showing an example of installation of an air conditioning device 100 according to the first embodiment. Hereinafter, the configuration of the air conditioning device 100 will be described based on FIG. 1. This air conditioning device 100 performs cooling or heating operation by utilizing a refrigerant circuit A that circulates a refrigerant and two heat medium circuits (first heat medium circuit B1, second heat medium circuit B2) (see FIG. 2 described later) that circulate a heat medium such as water or antifreeze. Here, in the following drawings including FIG. 1, the relationship of the sizes of the components may differ from the actual ones. In addition, when there is no need to particularly distinguish or specify multiple devices of the same type that are distinguished by subscripts, the subscripts may be omitted. In addition, the high and low of temperature, pressure, etc. are not particularly determined in relation to absolute values, but are relatively determined in the state, operation, etc. of a system, device, etc.

As shown in FIG. 1, the air conditioning apparatus 100 according to the first embodiment includes one heat source unit 1, multiple (six in the first embodiment) indoor units 3, a relay unit 2 interposed between the heat source unit 1 and the indoor units 3, and a control device 50 (see FIG. 2 described later). The heat source unit 1 and the relay unit 2 are connected by a first forward heat medium pipe 5a and a first return heat medium pipe 5b of the first heat medium pipe 5 through which the first heat medium flows, and a second forward heat medium pipe 6a and a second return heat medium pipe 6b of the second heat medium pipe 6 through which the second heat medium flows. The relay unit 2 and each of the multiple indoor units 3 are connected by an indoor side forward heat medium pipe 7a and an indoor side return heat medium pipe 7b through which the first heat medium or the second heat medium flows. The cold or hot heat generated by the heat source unit 1 is delivered to each indoor unit 3 via the first heat medium piping 5 having the first forward heat medium piping 5a and the first return heat medium piping 5b, the second heat medium piping 6 having the second forward heat medium piping 6a and the second return heat medium piping 6b, the indoor forward heat medium piping 7a, and the indoor return heat medium piping 7b.

The heat source unit 1 is typically placed in an outdoor space 8, which is the space outside a building 9 such as a building, and supplies cold or hot heat to each indoor unit 3 via a relay unit 2. The indoor units 3 are placed in a living space 9a, such as a room, inside the building 9, and supply air for cooling or heating to the living space 9a, which is the space to be air-conditioned. The relay unit 2 is placed separately from the heat source unit 1 and the indoor units 3 in a non-living space 9b, which is a space within the building 9 separate from the outdoor space 8 and the living space 9a, connects the heat source unit 1 and the indoor units 3, and transfers the cold or hot heat supplied from the heat source unit 1 to each indoor unit 3.

The refrigerant in the refrigerant circuit A may be, for example, a fluorine-based refrigerant or a hydrocarbon-based refrigerant with a low global warming potential (GWP). In addition, the refrigerant in the refrigerant circuit A may be, for example, a single refrigerant selected from R1234yf, R1234ze, R32, and R290, or a mixture of two or more of these, or a mixture of any of these with another refrigerant. In addition, the refrigerant in the refrigerant circuit A may be, for example, a mixed refrigerant containing R1132(E), or a mixed refrigerant containing R1123. In addition, the refrigerant in the refrigerant circuit A may be, for example, a mixed refrigerant of R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R447A, R446A, or R459A. In this embodiment 1, the refrigerant in the refrigerant circuit A is R290, which is a hydrocarbon refrigerant.

On the other hand, the heat medium in the heat medium circuit can be, for example, water, antifreeze, a mixture of water and antifreeze, or a mixture of water and an additive with high corrosion prevention properties.

The outdoor space 8 is assumed to be a place that exists outside the building 9, such as a rooftop as shown in Figure 1. The non-residential space 9b is assumed to be a space inside the building 9 that is separate from the residential space 9a, such as a hallway or other place where people are not always present, or the attic of a common zone, common areas with elevators, machine rooms, computer rooms, warehouses, etc. The residential space 9a is assumed to be a place inside the building 9 where people are always present or where a large or small number of people are temporarily present, such as offices, classrooms, conference rooms, cafeterias, server rooms, etc.

The heat source unit 1 and the relay unit 2 are connected using four heat medium pipes (first forward heat medium pipe 5a, first return heat medium pipe 5b, second forward heat medium pipe 6a, second return heat medium pipe 6b). The relay unit 2 and each indoor unit 3 are connected by two heat medium pipes (indoor forward heat medium pipe 7a, indoor return heat medium pipe 7b). In this way, by connecting the heat source unit 1 to the relay unit 2 with four heat medium pipes and connecting the indoor units 3 to the relay unit 2 with two heat medium pipes, the installation of the air conditioning device 100 is made easier.

FIG. 2 is a schematic diagram showing the circuit configuration of the air conditioning device 100 according to the first embodiment.

[Heat source unit 1]
The heat source unit 1 includes a compressor 10, a main refrigerant flow switching device 11, a heat source side heat exchanger 12, an on-off valve 13, two throttling devices 14 (a first throttling device 14a, a second throttling device 14b), two refrigerant-to-heat medium heat exchangers 15 (a first refrigerant-to-heat medium heat exchanger 15a, a second refrigerant-to-heat medium heat exchanger 15b), two refrigerant flow switching devices 16 (a first refrigerant flow switching device 16a, a second refrigerant flow switching device 16b), and two pumps 17 (a first pump 17a, a second pump 17b).

Compressor 10 draws in low-temperature, low-pressure refrigerant, compresses it, and discharges high-temperature, high-pressure refrigerant. Compressor 10 is an inverter compressor whose capacity, which is the amount of refrigerant discharged per unit time, is controlled, for example, by changing the operating frequency.

The main refrigerant flow switching device 11 is composed of, for example, a four-way valve, and switches the refrigerant flow during heating operation and the refrigerant flow during cooling operation.

The heat source side heat exchanger 12 functions as an evaporator during heating operation and as a condenser during cooling operation. The heat source side heat exchanger 12 exchanges heat between the air supplied from a blower (not shown) and the refrigerant, causing the refrigerant to evaporate and gasify or condense and liquefy.

The on-off valve 13 is provided in the refrigerant pipe 4 between the heat source side heat exchanger 12 and the two throttling devices 14, and opens and closes the refrigerant pipe 4. The on-off valve 13 is, for example, a solenoid valve that can be opened and closed by passing electricity through it.

The two throttling devices 14 function as pressure reducing valves or expansion valves, and reduce the pressure of the refrigerant to expand it. The first throttling device 14a is provided upstream of the first refrigerant-to-heat medium heat exchanger 15a in the refrigerant flow during cooling only operation, which will be described later. The second throttling device 14b is provided upstream of the second refrigerant-to-heat medium heat exchanger 15b in the refrigerant flow during cooling only operation, which will be described later. The two throttling devices 14 are variably controllable in terms of opening, for example electronic expansion valves.

The two refrigerant-to-heat medium heat exchangers 15 function as condensers when supplying hot heat to the indoor unit 3 in heating operation, and function as evaporators when supplying cold heat to the indoor unit 3 in cooling operation. The two refrigerant-to-heat medium heat exchangers 15 exchange heat between the refrigerant and the heat medium, and transfer the cold or hot heat generated in the heat source unit 1 and stored in the refrigerant to the heat medium. The first refrigerant-to-heat medium heat exchanger 15a is provided between the first throttling device 14a and the first refrigerant flow switching device 16a, and functions as an evaporator to cool the heat medium during the mixed cooling and heating operation in this embodiment 1 described later. The second refrigerant-to-heat medium heat exchanger 15b is provided between the second throttling device 14b and the second refrigerant flow switching device 16b, and functions as a condenser to heat the heat medium during the mixed cooling and heating operation in this embodiment 1 described later.

The two refrigerant flow switching devices 16 are, for example, four-way valves, and switch the flow of refrigerant so that the refrigerant-to-heat medium heat exchanger 15 acts as a condenser or an evaporator depending on the operation mode. The first refrigerant flow switching device 16a is provided downstream of the first refrigerant-to-heat medium heat exchanger 15a in the refrigerant flow during cooling only operation, which will be described later. The second refrigerant flow switching device 16b is provided downstream of the second refrigerant-to-heat medium heat exchanger 15b in the refrigerant flow during cooling only operation, which will be described later.

The two pumps 17 circulate the heat medium that flows through the heat medium piping. The first pump 17a is provided on the first heat medium piping 5 upstream of the first refrigerant-to-heat medium heat exchanger 15a, and circulates the first heat medium. The second pump 17b is provided on the second heat medium piping 6 upstream of the second refrigerant-to-heat medium heat exchanger 15b, and circulates the second heat medium. Each of the two pumps 17 is, for example, a pump whose capacity can be controlled, and the flow rate can be adjusted according to the magnitude of the load on the indoor unit 3.

[Indoor unit 3]
Each indoor unit 3 is equipped with a load-side heat exchanger 30. This load-side heat exchanger 30 is connected to the heat medium flow switching and flow rate control device 20 of the relay unit 2 by an indoor-side forward heat medium piping 7a and an indoor-side return heat medium piping 7b. This load-side heat exchanger 30 exchanges heat between the air supplied from a blower (not shown) and the heat medium, and generates heating air or cooling air to be supplied to the living space 9a.

In FIG. 2, an example is shown in which six indoor units 3 are connected to the relay unit 2, and are illustrated from the left side of the page as indoor unit 3a, indoor unit 3b, indoor unit 3c, indoor unit 3d, indoor unit 3d, indoor unit 3e, and indoor unit 3f. In addition, in accordance with the indoor units 3a to 3f, the load side heat exchangers 30 are also illustrated from the left side of the page as load side heat exchanger 30a, load side heat exchanger 30b, load side heat exchanger 30c, load side heat exchanger 30d, load side heat exchanger 30e, and load side heat exchanger 30f. Note that the number of connected indoor units 3 is not limited to six as shown in FIG. 2.

[Repeater 2]
The relay unit 2 includes six heat medium flow switching and flow control devices 20 (heat medium flow switching and flow control devices 20a to 20f) and two expansion tanks 21 (a first expansion tank 21a and a second expansion tank 21b).

The six heat medium flow switching flow control devices 20 are composed of a drive device and a valve body, and switch the flow path of the heat medium between the first refrigerant-to-heat medium heat exchanger 15a and the second refrigerant-to-heat medium heat exchanger 15b, and adjust the flow rate of the heat medium to each branch. The heat medium flow switching flow control devices 20 are provided in a number corresponding to the number of indoor units 3 installed (six in the first embodiment), and are structured so that they can be connected to each other. Furthermore, inside each of the heat medium flow switching flow control devices 20, one side is connected to the first refrigerant-to-heat medium heat exchanger 15a, and the other side is connected to the second refrigerant-to-heat medium heat exchanger 15b, and is also connected to the load side heat exchanger 30. In other words, the heat medium flow switching flow control device 20 switches the heat medium supplied to the connected indoor unit 3 between the first heat medium from the first refrigerant-to-heat medium heat exchanger 15a and the second heat medium from the second refrigerant-to-heat medium heat exchanger 15b. In FIG. 2, the heat medium flow switching flow control devices 20a, 20b, 20c, 20d, 20e, and 20f are illustrated from the left side of the page in correspondence with the indoor unit 3. Note that the number of heat medium flow switching flow control devices 20 connected is not limited to six as shown in FIG. 2.

The two expansion tanks 21 absorb the volume expansion of the heat medium flowing through the heat medium circuit. The first expansion tank 21a is provided in the first heat medium pipe 5 and absorbs the volume expansion of the first heat medium. The second expansion tank 21b is provided in the second heat medium pipe 6 and absorbs the volume expansion of the second heat medium.

In the air conditioning system 100, the compressor 10, main refrigerant flow switching device 11, heat source side heat exchanger 12, on-off valve 13, first throttling device 14a, the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a, and first refrigerant flow switching device 16a are connected in series by refrigerant piping 4, and the second throttling device 14b, the refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b, and the second refrigerant flow switching device 16b are connected in parallel to the first throttling device 14a, the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a, and the first refrigerant flow switching device 16a by refrigerant piping 4 to form a refrigerant circuit A in which the refrigerant circulates. The first pump 17a, the heat medium flow path of the first refrigerant-to-heat medium heat exchanger 15a, the heat medium flow path switching flow control device 20, and the load side heat exchanger 30 are connected by heat medium piping (the first heat medium piping 5 having the first forward heat medium piping 5a and the first return heat medium piping 5b, the indoor side forward heat medium piping 7a, and the indoor side return heat medium piping 7b), forming a first heat medium circuit B1 in which the first heat medium circulates. The second pump 17b, the heat medium flow path of the second refrigerant-to-heat medium heat exchanger 15b, the heat medium flow path switching flow control device 20, and the load side heat exchanger 30 are connected by heat medium piping (the second heat medium piping 6 having the second forward heat medium piping 6a and the second return heat medium piping 6b, the indoor side forward heat medium piping 7a, and the indoor side return heat medium piping 7b), forming a second heat medium circuit B2 in which the second heat medium circulates.

In the first heat medium circuit B1, a plurality of heat medium flow switching flow control devices 20 (six in the first embodiment) are connected in parallel to the first refrigerant-to-heat medium heat exchanger 15a via the first heat medium piping 5, and a load-side heat exchanger 30 is connected to each of the heat medium flow switching flow control devices 20 via the indoor-side forward heat medium piping 7a and the indoor-side return heat medium piping 7b. Similarly, in the second heat medium circuit B2, a plurality of heat medium flow switching flow control devices 20 (six in the first embodiment) are connected in parallel to the second refrigerant-to-heat medium heat exchanger 15b via the second heat medium piping 6, and a load-side heat exchanger 30 is connected to each of the heat medium flow switching flow control devices 20 via the indoor-side forward heat medium piping 7a and the indoor-side return heat medium piping 7b.

The refrigerant circuit A is installed in the heat source unit 1. The first heat medium circuit B1 and the second heat medium circuit B2 are installed across the heat source unit 1, the relay unit 2, and the indoor unit 3.

In the air-conditioning device 100, the first refrigerant-to-heat medium heat exchanger 15a exchanges heat between the refrigerant circulating in the refrigerant circuit A and the first heat medium circulating in the first heat medium circuit B1, and the second refrigerant-to-heat medium heat exchanger 15b exchanges heat between the refrigerant circulating in the refrigerant circuit A and the second heat medium circulating in the second heat medium circuit B2. By using such a configuration, the air-conditioning device 100 can achieve optimal cooling or heating operation according to the indoor load.

FIG. 3 is a schematic diagram showing the circuit configuration of a modified example of the air conditioning device 100 according to the first embodiment. In the first embodiment, as shown in FIG. 2, an expansion tank 21 (first expansion tank 21a, second expansion tank 21b) is provided in each of the two heat medium pipes (first heat medium pipe 5, second heat medium pipe 6), but this is not limited to the configuration. As shown in FIG. 3, the expansion tank 21 may be provided in only one of the two heat medium pipes (first heat medium pipe 5 in the modified example), and the first heat medium pipe 5 and the second heat medium pipe 6 may be connected at least at one point by a connecting pipe 60 having an inner diameter smaller than the first heat medium pipe 5 and the second heat medium pipe 6.

The heat medium flow switching flow adjustment device 20 is also capable of flow adjustment, and controls the flow rate of the heat medium flowing through the heat medium pipes (first heat medium pipe 5, second heat medium pipe 6) by adjusting the opening area. One side of the heat medium flow switching flow adjustment device 20 is connected to the load side heat exchanger 30, and the other side is connected to the refrigerant-heat medium heat exchanger 15. In other words, the heat medium flow switching flow adjustment device 20 adjusts the amount of heat medium flowing into the indoor unit 3 depending on the temperature of the heat medium flowing into the indoor unit 3 and the temperature of the heat medium flowing out of the indoor unit 3, making it possible to provide the indoor unit 3 with an optimal amount of heat medium according to the indoor load.

In addition, when the indoor unit 3 is stopped or the load is not required such as thermo OFF, or when it is desired to block the flow path of the heat medium due to maintenance, the supply of heat medium to the indoor unit 3 can be stopped by fully closing the heat medium flow path switching and flow control device 20.

The control device 50 is composed of a microcomputer and the like, and controls the drive frequency of the compressor 10, the rotation speed (including ON/OFF) of the blower (not shown), switching of the main refrigerant flow switching device 11, opening and closing of the on-off valve 13, the opening degree of the throttling device 14, switching of the refrigerant flow switching device 16, the drive speed (including ON/OFF) of the pump 17, and switching and drive of the heat medium flow switching flow rate adjustment device 20 based on information detected by various detection means and instructions from a remote control.

The first heat medium pipe 5 and the second heat medium pipe 6 are branched (six branches each in the first embodiment) according to the number of indoor units 3 connected to the relay unit 2. The first heat medium pipe 5 and the second heat medium pipe 6 are connected by a heat medium flow path switching flow rate adjustment device 20. The control device 50 controls the heat medium flow path switching flow rate adjustment device 20 to determine whether the first heat medium from the first refrigerant-to-heat medium heat exchanger 15a is caused to flow into the load side heat exchanger 30, or the second heat medium from the second refrigerant-to-heat medium heat exchanger 15b is caused to flow into the load side heat exchanger 30.

Next, we will explain the behavior of the refrigerant in various operation modes of the air conditioning device 100 configured as described above. The air conditioning device 100 has at least the following operation modes: full cooling operation, cooling-dominated operation, full heating operation, and heating-dominated operation, and performs one of these operations.

Full cooling operation is a type of cooling operation in which all indoor units 3 perform cooling for the space to be air-conditioned. Cooling-dominated operation is a type of cooling operation in which multiple indoor units 3 are mixed, some of which perform cooling and some of which perform heating, and the cooling load of the indoor units 3 performing cooling for the space to be air-conditioned exceeds the heating load of the indoor units 3 performing heating for the space to be air-conditioned. Full heating operation is a type of heating operation in which all indoor units 3 perform heating for the space to be air-conditioned. Heating-dominated operation is a type of heating operation in which multiple indoor units 3 are mixed, some of which perform cooling and some of which perform heating, and the heating load of the indoor units 3 performing heating for the space to be air-conditioned exceeds the cooling load of the indoor units 3 performing cooling for the space to be air-conditioned. In the following, cooling-dominated operation and heating-dominated operation are collectively referred to as mixed cooling and heating operation.

[Full cooling operation]
Fig. 4 is a refrigerant circuit diagram showing the flow of refrigerant during full cooling operation of the air-conditioning apparatus 100 according to embodiment 1. In Fig. 4, a cooling load is generated in all of the load-side heat exchangers 30a to 30f. In Fig. 4, the flow direction of the refrigerant is indicated by solid arrows, and the flow direction of the heat medium is indicated by dashed arrows.

In the full cooling operation, as shown in FIG. 4, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 are switched so that the discharge side of the compressor 10 is connected to the heat source side heat exchanger 12 and the suction side of the compressor 10 is connected to the two refrigerant-to-heat medium heat exchangers 15. In addition, the on-off valve 13 is opened. Therefore, the first refrigerant-to-heat medium heat exchanger 15a and the second refrigerant-to-heat medium heat exchanger 15b are connected in parallel.

First, the flow of refrigerant in the refrigerant circuit A will be described. The low-temperature, low-pressure refrigerant is compressed by the compressor 10 and becomes a high-temperature, high-pressure gas refrigerant, which is discharged from the compressor 10. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 through the main refrigerant flow switching device 11. The high-temperature, high-pressure gas refrigerant that flows into the heat source side heat exchanger 12 condenses while releasing heat to the outdoor air, becoming a medium-temperature, high-pressure liquid refrigerant. The medium-temperature, high-pressure liquid refrigerant that flows out of the heat source side heat exchanger 12 then branches through the on-off valve 13 and flows into the first throttling device 14a and the second throttling device 14b, respectively, and is depressurized. The low-temperature, low-pressure two-phase refrigerant depressurized by the first throttling device 14a and the low-temperature, low-pressure two-phase refrigerant depressurized by the second throttling device 14b flow into the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a and the refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b, respectively. The low-temperature, low-pressure two-phase refrigerant flowing into the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a and the low-temperature, low-pressure two-phase refrigerant flowing into the refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b evaporate while absorbing heat from the first heat medium flowing into the heat medium flow path of the first refrigerant-to-heat medium heat exchanger 15a and the second heat medium flowing into the heat medium flow path of the second refrigerant-to-heat medium heat exchanger 15b, respectively, and become a low-temperature, low-pressure gas refrigerant. After that, the low-temperature, low-pressure gas refrigerant flowing out of the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a and the low-temperature, low-pressure gas refrigerant flowing out of the refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b are respectively merged through the first refrigerant flow path switching device 16a and the second refrigerant flow path switching device 16b, and then are sucked into the compressor 10 again through the main refrigerant flow path switching device 11.

Next, the flow of the first heat medium in the first heat medium circuit B1 and the flow of the second heat medium in the second heat medium circuit B2 will be described. The cold of the refrigerant is transferred to the first heat medium in the first refrigerant-heat medium heat exchanger 15a, and the cooled first heat medium flows through the first heat medium piping 5 by the action of the first pump 17a. The cold of the refrigerant is transferred to the second heat medium in the second refrigerant-heat medium heat exchanger 15b, and the cooled second heat medium flows through the second heat medium piping 6 by the action of the second pump 17b. The cooled first heat medium and second heat medium each flow into the heat medium flow path switching flow control device 20. The first heat medium or second heat medium flowing out of the heat medium flow path switching flow control device 20 flows into the load side heat exchangers 30a to 30f where a cold load is generated. At this time, the flow rate of the first heat medium or the second heat medium is controlled to a flow rate required to cover the air conditioning load required in the room by the flow rate adjustment action of the heat medium flow switching flow control device 20, and flows into the load side heat exchangers 30a to 30f. Then, the heat medium absorbs heat from the indoor air in the load side heat exchangers 30a to 30f, thereby cooling the living space 9a. After that, the first heat medium or the second heat medium flows out of the load side heat exchangers 30a to 30f and flows back into the heat medium flow switching flow control device 20. The first heat medium and the second heat medium that flow out of the heat medium flow switching flow control device 20 respectively flow into the first refrigerant-to-heat medium heat exchanger 15a and the second refrigerant-to-heat medium heat exchanger 15b, and transfer the amount of heat supplied from the living space 9a through the indoor unit 3 to the refrigerant side, and flow back into the heat medium flow switching flow control device 20. In addition, only one of the first heat medium and the second heat medium may flow into or out of the load side heat exchangers 30a to 30f, or the first heat medium and the second heat medium may flow into or out of the load side heat exchangers 30a to 30f alternately. The first heat medium and the second heat medium are not mixed and flow into or out of the load side heat exchangers 30a to 30f, and only the first heat medium or the second heat medium flows into or out of the load side heat exchangers 30a to 30f.

Here, the air conditioning load required in the living space 9a can be met, for example, by providing a temperature sensor (not shown) on either the outlet side of the first refrigerant-to-heat medium heat exchanger 15a or the outlet side of the second refrigerant-to-heat medium heat exchanger 15b, and controlling the heat medium flow path switching and flow rate adjustment device 20 to maintain the temperature detected by the temperature sensor at a target value. Note that temperature sensors (not shown) may be provided on both the outlet side of the first refrigerant-to-heat medium heat exchanger 15a and the outlet side of the second refrigerant-to-heat medium heat exchanger 15b, and the average temperature detected by the temperature sensors may be used, or either the higher or lower temperature may be used.

[Full heating operation]
Fig. 5 is a refrigerant circuit diagram showing the flow of refrigerant during full heating operation of the air conditioning apparatus 100 according to embodiment 1. In Fig. 5, a heating load is generated in all of the load-side heat exchangers 30a to 30f. In Fig. 5, the flow direction of the refrigerant is indicated by solid arrows, and the flow direction of the heat medium is indicated by dashed arrows.

In the full heating operation, as shown in FIG. 5, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 are switched so that the suction side of the compressor 10 is connected to the heat source side heat exchanger 12 and the discharge side of the compressor 10 is connected to the two refrigerant-to-heat medium heat exchangers 15. In addition, the on-off valve 13 is opened. Therefore, the first refrigerant-to-heat medium heat exchanger 15a and the second refrigerant-to-heat medium heat exchanger 15b are connected in parallel.

First, the flow of refrigerant in the refrigerant circuit A will be described. The low-temperature, low-pressure refrigerant is compressed by the compressor 10, becomes a high-temperature, high-pressure gas refrigerant, and is discharged from the compressor 10. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 branches through the main refrigerant flow switching device 11, and then flows through the first refrigerant flow switching device 16a and the second refrigerant flow switching device 16b into the refrigerant flow path of the first refrigerant-intermediate heat medium heat exchanger 15a and the refrigerant flow path of the second refrigerant-intermediate heat medium heat exchanger 15b. The high-temperature, high-pressure gas refrigerant that flows into the refrigerant flow path of the first refrigerant-intermediate heat medium heat exchanger 15a and the high-temperature, high-pressure gas refrigerant that flows into the refrigerant flow path of the second refrigerant-intermediate heat medium heat exchanger 15b condense while releasing heat to the first heat medium that flows into the heat medium flow path of the first refrigerant-intermediate heat medium heat exchanger 15a and the second heat medium that flows into the heat medium flow path of the second refrigerant-intermediate heat exchanger 15b, respectively, and become a medium-temperature, high-pressure liquid refrigerant. Then, the medium-temperature, high-pressure liquid refrigerant flowing out of the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a and the medium-temperature, high-pressure liquid refrigerant flowing out of the refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b flow into the first throttling device 14a and the second throttling device 14b, respectively, and are decompressed. The low-temperature, low-pressure two-phase refrigerant decompressed by the first throttling device 14a and the low-temperature, low-pressure two-phase refrigerant decompressed by the second throttling device 14b merge and then flow into the heat source side heat exchanger 12 through the on-off valve 13. The low-temperature, low-pressure two-phase refrigerant that flows into the heat source side heat exchanger 12 evaporates while absorbing heat from the outdoor air, and becomes a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant that flows out of the heat source side heat exchanger 12 passes through the main refrigerant flow path switching device 11 and is sucked back into the compressor 10.

Next, the flow of the first heat medium in the first heat medium circuit B1 and the flow of the second heat medium in the second heat medium circuit B2 will be described. The hot heat of the refrigerant is transferred to the first heat medium in the first refrigerant-to-heat medium heat exchanger 15a, and the heated first heat medium flows through the first heat medium piping 5 by the action of the first pump 17a. The hot heat of the refrigerant is transferred to the second heat medium in the second refrigerant-to-heat medium heat exchanger 15b, and the heated second heat medium flows through the second heat medium piping 6 by the action of the second pump 17b. The heated first heat medium and second heat medium each flow into the heat medium flow path switching flow control device 20. The first heat medium or second heat medium flowing out of the heat medium flow path switching flow control device 20 flows into the load-side heat exchangers 30a to 30f where a hot heat load is generated. At this time, the flow rate of the first heat medium or the second heat medium is controlled to a flow rate required to cover the air conditioning load required in the room by the flow rate adjustment action of the heat medium flow switching flow control device 20, and flows into the load side heat exchangers 30a to 30f. Then, the heat medium dissipates heat to the indoor air in the load side heat exchangers 30a to 30f, thereby heating the living space 9a. After that, the first heat medium or the second heat medium flows out of the load side heat exchangers 30a to 30f and flows back into the heat medium flow switching flow control device 20. The first heat medium and the second heat medium that flow out of the heat medium flow switching flow control device 20 respectively flow into the first refrigerant-to-heat medium heat exchanger 15a and the second refrigerant-to-heat medium heat exchanger 15b, receive the amount of heat supplied to the living space 9a through the indoor unit 3 from the refrigerant side, and flow back into the heat medium flow switching flow control device 20. In addition, only one of the first heat medium and the second heat medium may flow into or out of the load side heat exchangers 30a to 30f, or the first heat medium and the second heat medium may flow into or out of the load side heat exchangers 30a to 30f alternately. The first heat medium and the second heat medium are not mixed and flow into or out of the load side heat exchangers 30a to 30f, and only the first heat medium or the second heat medium flows into or out of the load side heat exchangers 30a to 30f.

[Cooling main operation]
Fig. 6 is a refrigerant circuit diagram showing the flow of refrigerant during cooling-dominated operation of the air-conditioning apparatus 100 according to embodiment 1. In Fig. 6, a cooling load is generated in the load-side heat exchangers 30a to 30c, and a heating load is generated in the load-side heat exchangers 30d to 30f. In Fig. 6, the flow direction of the refrigerant is indicated by solid arrows, and the flow direction of the heat medium is indicated by dashed arrows.

In cooling-dominated operation, as shown in FIG. 6, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 are switched so that the discharge side of the compressor 10 is connected to the heat source side heat exchanger 12 and the suction side of the compressor 10 is connected to one of the two refrigerant-to-heat medium heat exchangers 15 (the first refrigerant-to-heat medium heat exchanger 15a in the first embodiment). In addition, the on-off valve 13 is closed and the first throttling device 14a is opened (fully open). Therefore, the first refrigerant-to-heat medium heat exchanger 15a and the second refrigerant-to-heat medium heat exchanger 15b are connected in series. Note that the second throttling device 14b may be opened (fully open) instead of the first throttling device 14a.

First, the flow of refrigerant in the refrigerant circuit A will be described. The low-temperature, low-pressure refrigerant is compressed by the compressor 10, becomes a high-temperature, high-pressure gas refrigerant, and is discharged from the compressor 10. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 through the main refrigerant flow switching device 11. The high-temperature, high-pressure gas refrigerant that flows into the heat source side heat exchanger 12 condenses while releasing heat to the outdoor air, and becomes a medium-temperature, high-pressure liquid refrigerant. After that, the medium-temperature, high-pressure liquid refrigerant that flows out of the heat source side heat exchanger 12 flows into the refrigerant flow path of the second refrigerant-intermediate heat medium heat exchanger 15b through the second refrigerant flow switching device 16b. The medium-temperature, high-pressure liquid refrigerant that flows into the refrigerant flow path of the second refrigerant-intermediate heat medium heat exchanger 15b releases heat to the second heat medium that flows into the heat medium flow path of the second refrigerant-intermediate heat exchanger 15b, and becomes a low-temperature, high-pressure liquid refrigerant. Then, the low-temperature, high-pressure liquid refrigerant flowing out of the refrigerant flow path of the second refrigerant-intermediate heat exchanger 15b flows into the second throttling device 14b and is depressurized. The low-temperature, low-pressure two-phase refrigerant depressurized by the second throttling device 14b passes through the fully opened first throttling device 14a and flows into the refrigerant flow path of the first refrigerant-intermediate heat exchanger 15a. The low-temperature, low-pressure two-phase refrigerant flowing into the refrigerant flow path of the first refrigerant-intermediate heat exchanger 15a evaporates while absorbing heat from the first heat medium flowing into the heat medium flow path of the first refrigerant-intermediate heat exchanger 15a, becoming a low-temperature, low-pressure gas refrigerant. Then, the low-temperature, low-pressure gas refrigerant flowing out of the refrigerant flow path of the first refrigerant-intermediate heat exchanger 15a passes through the first refrigerant flow path switching device 16a and the main refrigerant flow path switching device 11 and is sucked back into the compressor 10. When the second throttling device 14b is fully open, the low-temperature, high-pressure liquid refrigerant that flows out of the refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b passes through the fully open second throttling device 14b and flows into the first throttling device 14a where it is depressurized.

Next, the flow of the first heat medium in the first heat medium circuit B1 and the flow of the second heat medium in the second heat medium circuit B2 will be described. The cold heat of the refrigerant is transferred to the first heat medium in the first refrigerant-to-heat medium heat exchanger 15a, and the cooled first heat medium flows through the first heat medium pipe 5 by the action of the first pump 17a. The hot heat of the refrigerant is transferred to the second heat medium in the second refrigerant-to-heat medium heat exchanger 15b, and the warmed second heat medium flows through the second heat medium pipe 6 by the action of the second pump 17b. The first heat medium cooled in the first refrigerant-to-heat medium heat exchanger 15a flows into the load side heat exchangers 30a to 30c where a cold load is generated via the heat medium flow path switching flow rate adjustment device 20. The heat medium then absorbs heat from the indoor air in the load side heat exchangers 30a to 30c, thereby cooling the living space 9a. The second heat medium warmed by the second refrigerant-to-heat medium heat exchanger 15b flows into the load-side heat exchangers 30d to 30f where a heating load is generated, via the heat medium flow switching flow control device 20. The heat medium then dissipates heat to the indoor air in the load-side heat exchangers 30d to 30f, thereby heating the living space 9a. At this time, the flow rate of the first heat medium is controlled to a flow rate required to cover the air conditioning load required in the room by the flow rate control action of the heat medium flow switching flow control device 20, and flows into the load-side heat exchangers 30a to 30c. The flow rate of the second heat medium is controlled to a flow rate required to cover the air conditioning load required in the room by the flow rate control action of the heat medium flow switching flow control device 20, and flows into the load-side heat exchangers 30d to 30f. After that, the first heat medium and the second heat medium flow out of the load side heat exchangers 30a to 30c and the load side heat exchangers 30d to 30f, respectively, and flow back into the heat medium flow switching flow control device 20. The first heat medium that flows out of the heat medium flow switching flow control device 20 flows into the first refrigerant-to-heat medium heat exchanger 15a and transfers the amount of heat supplied from the living space 9a through the indoor unit 3 to the refrigerant side. The second heat medium that flows out of the heat medium flow switching flow control device 20 flows into the second refrigerant-to-heat medium heat exchanger 15b and receives the amount of heat supplied to the living space 9a through the indoor unit 3 from the refrigerant side.

In this embodiment 1, in cooling-dominant operation, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 are switched so that the discharge side of the compressor 10 is connected to the heat source side heat exchanger 12 and the suction side of the compressor 10 is connected to the first refrigerant-to-heat medium heat exchanger 15a, the second heat fluid is heated in the second refrigerant-to-heat medium heat exchanger 15b, and the first heat medium is cooled in the first refrigerant-to-heat medium heat exchanger 15a. However, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 may be switched so that the discharge side of the compressor 10 is connected to the heat source side heat exchanger 12 and the suction side of the compressor 10 is connected to the second refrigerant-to-heat medium heat exchanger 15b, the first heat fluid is heated in the first refrigerant-to-heat medium heat exchanger 15a, and the second heat medium is cooled in the second refrigerant-to-heat medium heat exchanger 15b.

[Heating-dominant operation]
Fig. 7 is a refrigerant circuit diagram showing the flow of refrigerant during heating-dominant operation of the air-conditioning apparatus 100 according to embodiment 1. In Fig. 7, a cooling load is generated in the load-side heat exchangers 30a to 30c, and a heating load is generated in the load-side heat exchangers 30d to 30f. In Fig. 7, the flow direction of the refrigerant is indicated by solid arrows, and the flow direction of the heat medium is indicated by dashed arrows.

In heating-dominated operation, as shown in FIG. 7, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 are switched so that the suction side of the compressor 10 is connected to the heat source side heat exchanger 12 and the discharge side of the compressor 10 is connected to one of the two refrigerant-to-heat medium heat exchangers 15 (the second refrigerant-to-heat medium heat exchanger 15b in the first embodiment). In addition, the on-off valve 13 is closed and the first throttling device 14a is opened (fully open). Therefore, the first refrigerant-to-heat medium heat exchanger 15a and the second refrigerant-to-heat medium heat exchanger 15b are connected in series. Note that the second throttling device 14b may be opened (fully open) instead of the first throttling device 14a.

First, the flow of refrigerant in the refrigerant circuit A will be described. The low-temperature, low-pressure refrigerant is compressed by the compressor 10, and becomes a high-temperature, high-pressure gas refrigerant, which is discharged from the compressor 10. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 flows into the refrigerant flow path of the second refrigerant-intermediate heat exchanger 15b through the main refrigerant flow path switching device 11 and the second refrigerant flow path switching device 16b. The high-temperature, high-pressure gas refrigerant that flows into the refrigerant flow path of the second refrigerant-intermediate heat exchanger 15b condenses while releasing heat to the second heat medium that flows into the heat medium flow path of the second refrigerant-intermediate heat exchanger 15b, and becomes a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the refrigerant flow path of the second refrigerant-intermediate heat exchanger 15b then flows into the second throttling device 14b and is reduced in pressure. The low-temperature, low-pressure two-phase refrigerant decompressed by the second throttling device 14b passes through the fully opened first throttling device 14a and flows into the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a. The low-temperature, low-pressure two-phase refrigerant that flows into the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a absorbs heat from the first heat medium that flows into the heat medium flow path of the first refrigerant-to-heat medium heat exchanger 15a. Then, the low-temperature, low-pressure two-phase refrigerant that flows out of the refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a flows into the heat source side heat exchanger 12 through the first refrigerant flow path switching device 16a. The low-temperature, low-pressure two-phase refrigerant that flows into the heat source side heat exchanger 12 evaporates while absorbing heat from the outdoor air, and becomes a low-temperature, low-pressure gas refrigerant. Then, the low-temperature, low-pressure gas refrigerant that flows out of the heat source side heat exchanger 12 passes through the main refrigerant flow path switching device 11 and is sucked into the compressor 10 again. When the second throttling device 14b is fully open, the low-temperature, high-pressure liquid refrigerant that flows out of the refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b passes through the fully open second throttling device 14b and flows into the first throttling device 14a where it is depressurized.

Next, the flow of the first heat medium in the first heat medium circuit B1 and the flow of the second heat medium in the second heat medium circuit B2 will be described. The cold heat of the refrigerant is transferred to the first heat medium in the first refrigerant-to-heat medium heat exchanger 15a, and the cooled first heat medium flows through the first heat medium pipe 5 by the action of the first pump 17a. The hot heat of the refrigerant is transferred to the second heat medium in the second refrigerant-to-heat medium heat exchanger 15b, and the warmed second heat medium flows through the second heat medium pipe 6 by the action of the second pump 17b. The first heat medium cooled in the first refrigerant-to-heat medium heat exchanger 15a flows into the load side heat exchangers 30a to 30c where a cold load is generated via the heat medium flow path switching flow rate adjustment device 20. The heat medium then absorbs heat from the indoor air in the load side heat exchangers 30a to 30c, thereby cooling the living space 9a. The second heat medium warmed by the second refrigerant-to-heat medium heat exchanger 15b flows into the load-side heat exchangers 30d to 30f where a heating load is generated, via the heat medium flow switching flow control device 20. The heat medium then dissipates heat to the indoor air in the load-side heat exchangers 30d to 30f, thereby heating the living space 9a. At this time, the flow rate of the first heat medium is controlled to a flow rate required to cover the air conditioning load required in the room by the flow rate control action of the heat medium flow switching flow control device 20, and flows into the load-side heat exchangers 30a to 30c. The flow rate of the second heat medium is controlled to a flow rate required to cover the air conditioning load required in the room by the flow rate control action of the heat medium flow switching flow control device 20, and flows into the load-side heat exchangers 30d to 30f. After that, the first heat medium and the second heat medium flow out of the load side heat exchangers 30a to 30c and the load side heat exchangers 30d to 30f, respectively, and flow back into the heat medium flow switching flow control device 20. The first heat medium that flows out of the heat medium flow switching flow control device 20 flows into the first refrigerant-to-heat medium heat exchanger 15a and transfers the amount of heat supplied from the living space 9a through the indoor unit 3 to the refrigerant side. The second heat medium that flows out of the heat medium flow switching flow control device 20 flows into the second refrigerant-to-heat medium heat exchanger 15b and receives the amount of heat supplied to the living space 9a through the indoor unit 3 from the refrigerant side.

In this embodiment 1, in heating-dominant operation, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 are switched so that the suction side of the compressor 10 is connected to the heat source side heat exchanger 12 and the discharge side of the compressor 10 is connected to the second refrigerant-to-heat medium heat exchanger 15b, the second heat fluid is heated in the second refrigerant-to-heat medium heat exchanger 15b, and the first heat medium is cooled in the first refrigerant-to-heat medium heat exchanger 15a. However, the main refrigerant flow switching device 11 and the two refrigerant flow switching devices 16 may be switched so that the suction side of the compressor 10 is connected to the heat source side heat exchanger 12 and the discharge side of the compressor 10 is connected to the first refrigerant-to-heat medium heat exchanger 15a, the first heat fluid is heated in the first refrigerant-to-heat medium heat exchanger 15a, and the second heat medium is cooled in the second refrigerant-to-heat medium heat exchanger 15b.

Note that the number of heat source units 1, indoor units 3, and relay units 2 connected is not limited to the number shown in FIG. 2. If there are two or more indoor units 3, cooling operation and heating operation can be performed simultaneously in different indoor units 3. Even if there is only one indoor unit 3, it is possible to switch between cooling operation and heating operation.

As described above, the air conditioning apparatus 100 according to the first embodiment includes a compressor 10, a main refrigerant flow switching device 11, a heat source side heat exchanger 12, an on-off valve 13, a first throttling device 14a, a refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a, and a first refrigerant flow switching device 16a, which are connected by a refrigerant piping 4, and a second throttling device 14b, a refrigerant flow path of the second refrigerant-to-heat medium heat exchanger 15b, and a second refrigerant flow switching device 16b, which are connected by a refrigerant piping 4. 4a, a refrigerant flow path of the first refrigerant-to-heat medium heat exchanger 15a, a refrigerant circuit A connected in parallel to the first refrigerant flow switching device 16a by refrigerant piping 4 and in which the refrigerant circulates, a part of a first heat medium circuit B1 in which the first pump 17a and the heat medium flow path of the first refrigerant-to-heat medium heat exchanger 15a are connected by first heat medium piping 5 and in which the first heat medium circulates, and a heat medium flow path of the second pump 17b and the second refrigerant-to-heat medium heat exchanger 15b are connected by a second heat medium piping 5 and in which the second heat medium circulates. The system includes a heat source unit 1 having a part of a second heat medium circuit B2 in which the second heat medium circulates, a plurality of indoor units 3 having a load-side heat exchanger 30, and a relay unit 2 connected between the heat source unit 1 and the plurality of indoor units 3. The relay unit 2 is connected to each of the plurality of indoor units 3 by an indoor-side forward heat medium pipe 7a and an indoor-side return heat medium pipe 7b, and switches the heat medium supplied to each of the plurality of indoor units 3 via the indoor-side forward heat medium pipe 7a and the indoor-side return heat medium pipe 7b between the first heat medium and the second heat medium. The first heat medium pipe 5 has a first forward heat medium pipe 5a and a first return heat medium pipe 5b that connect the heat source unit 1 and the relay unit 2, and the second heat medium pipe 6 has a second forward heat medium pipe 6a and a second return heat medium pipe 6b that connect the heat source unit 1 and the relay unit 2.

According to the air conditioning device 100 according to the first embodiment, the refrigerant circuit A in which the refrigerant circulates is provided in the heat source unit 1, the heat source unit 1 and the relay unit 2 are connected by the first forward heat medium pipe 5a and the first return heat medium pipe 5b through which the first heat medium flows, and the second forward heat medium pipe 6a and the second return heat medium pipe 6b through which the second heat medium flows, and the relay unit 2 and each of the indoor units 3 are connected by the indoor forward heat medium pipe 7a and the indoor return heat medium pipe 7b through which the first heat medium or the second heat medium flows. In other words, the refrigerant does not flow through the pipes connecting the heat source unit 1 and the relay unit 2, and the pipes connecting the relay unit 2 and the indoor units 3, and the flow of the refrigerant can be closed inside the heat source unit 1, which is generally installed outdoors, so that the amount of refrigerant required in the refrigerant circuit A can be reduced. In addition, the refrigerant does not flow through the relay unit 2 and the indoor units 3, which are generally installed indoors, so that the risk of refrigerant leakage indoors can be reduced.

Embodiment 2.
Hereinafter, the second embodiment will be described, but explanations of parts that overlap with the first embodiment will be omitted, and parts that are the same as or equivalent to the first embodiment will be given the same reference numerals. Also, in the second embodiment, the differences from the first embodiment will be mainly described.

FIG. 8 is a schematic diagram showing the circuit configuration of the heat source unit 1 side of the air conditioning device 200 according to embodiment 2. As shown in FIG. 8, the air conditioning device 200 according to embodiment 2 includes a plurality of heat source units 1 (1-1, 1-2, 1-3) (three in embodiment 2). The first forward heat medium piping 5a has branched first forward heat medium piping 5a-1, 5a-2, 5a-3 connected to the outlet side of each of the heat source units 1-1, 1-2, 1-3. The first return heat medium piping 5b has branched first return heat medium piping 5b-1, 5b-2, 5b-3 connected to the inlet side of each of the heat source units 1-1, 1-2, 1-3. The second forward heat medium piping 6a has branched second forward heat medium piping 6a-1, 6a-2, 6a-3 connected to the outlet side of each of the heat source units 1-1, 1-2, 1-3. The second return heat medium pipe 6b has branched second return heat medium pipes 6b-1, 6b-2, and 6b-3 connected to the inflow sides of the heat source units 1-1, 1-2, and 1-3. The air conditioning device 200 includes a first forward header 41a that connects to the branched first forward heat medium pipes 5a-1, 5a-2, and 5a-3 on the outflow side of the first forward heat medium pipe 5a from each heat source unit 1, and a first return header 42a that connects to the branched first return heat medium pipes 5b-1, 5b-2, and 5b-3 on the inflow side of the first return heat medium pipe 5b to each heat source unit 1. Also, the second forward heat medium piping 6a is provided with a second forward header 41b that connects to the branched second forward heat medium piping 6a-1, 6a-2, 6a-3 on the outflow side from each heat source unit 1, and the second return header 42b that connects to the branched second return heat medium piping 6b-1, 6b-2, 6b-3 on the inflow side to each heat source unit 1 of the second return heat medium piping 6b. Each heat source unit 1 is connected to the relay unit 2 in parallel with each other via the first forward header 41a, the first return header 42a, the second forward header 41b, and the second return header 42b.

In this way, by configuring multiple heat source units 1 to be connected in parallel, it is possible to realize the required horsepower (HP) by connecting multiple heat source units 1 in parallel. Therefore, a small number of types of horsepower of heat source units 1 can be used to accommodate many types of horsepower, and it is not necessary to manufacture heat source units 1 for each horsepower. For example, two types of horsepower (4 horsepower and 6 horsepower) of heat source units 1 can accommodate many types of horsepower, such as 4 horsepower, 6 horsepower, 8 horsepower, 10 horsepower, 12 horsepower, 14 horsepower, 16 horsepower, and so on. For example, 10 horsepower can be achieved by connecting one 4 horsepower heat source unit 1 and one 6 horsepower heat source unit 1 in parallel, and 14 horsepower can be achieved by connecting two 4 horsepower heat source units 1 and one 6 horsepower heat source unit 1 in parallel.

As described above, the air conditioning device 200 according to the second embodiment includes a plurality of heat source units 1, a first outbound header 41a to which the first outbound heat medium piping 5a of each heat source unit 1 is connected, a first return header 42a to which the first return heat medium piping 5b of each heat source unit 1 is connected, a second outbound header 41b to which the second outbound heat medium piping 6a of each heat source unit 1 is connected, and a second return header 42b to which the second return heat medium piping 6b of each heat source unit 1 is connected, and each heat source unit 1 is connected to the relay unit 2 in parallel with each other via the first outbound header 41a, the first return header 42a, the second outbound header 41b, and the second return header 42b.

According to the air conditioning device 200 according to the second embodiment, multiple heat source units 1 can be connected in parallel, so the required horsepower (HP) can be achieved by connecting multiple heat source units 1 in parallel. Therefore, a small number of types of horsepower of heat source units 1 can be used to accommodate many types of horsepower, and there is no need to manufacture heat source units 1 for each horsepower.

1 Heat source unit, 1-1 to 1-3 Heat source unit, 2 Relay unit, 3 Indoor unit, 3a to 3f Indoor unit, 4 Refrigerant piping, 5 First heat medium piping, 5a First forward heat medium piping, 5a-1 to 5a-3 First forward heat medium piping, 5b First return heat medium piping, 5b-1 to 5b-3 First return heat medium piping, 6 Second heat medium piping, 6a Second forward heat medium piping, 6a-1 to 6a-3 Second forward heat medium piping, 6b second return heat medium piping, 6b-1 to 6b-3 second return heat medium piping, 7a indoor forward heat medium piping, 7b indoor return heat medium piping, 8 outdoor space, 9 building, 9a living space, 9b non-living space, 10 compressor, 11 main refrigerant flow switching device, 12 heat source side heat exchanger, 13 on-off valve, 14 throttling device, 14a first throttling device, 1 4b second throttling device, 15 refrigerant-to-heat medium heat exchanger, 15a first refrigerant-to-heat medium heat exchanger, 15b second refrigerant-to-heat medium heat exchanger, 16 refrigerant flow switching device, 16a first refrigerant flow switching device, 16b second refrigerant flow switching device, 17 pump, 17a first pump, 17b second pump, 20 heat medium flow switching flow control device, 20a to 20f heat medium flow switching flow control device, 21 expansion tank, 21a first expansion tank, 21b second expansion tank, 30 load side heat exchanger, 30a to 30f load side heat exchanger, 41a first outgoing header, 41b second outgoing header, 42a first return header, 42b second return header, 50 control device, 60 connection piping, 100 air conditioning device, 200 air conditioning device.

Claims (5)

a refrigerant circuit in which a refrigerant circulates, wherein a compressor, a main refrigerant flow switching device, a heat source side heat exchanger, an on-off valve, a first throttling device, a refrigerant flow path of a first refrigerant-intermediate heat exchanger, and a first refrigerant flow switching device are connected by refrigerant piping, and a second throttling device, a refrigerant flow path of the second refrigerant-intermediate heat exchanger, and a second refrigerant flow switching device are connected in parallel to the first throttling device, the refrigerant flow path of the first refrigerant-intermediate heat exchanger, and the first refrigerant flow switching device by the refrigerant piping;
a part of a first heat medium circuit in which a first pump and a heat medium flow path of the first refrigerant-to-heat medium heat exchanger are connected by a first heat medium pipe, and a first heat medium circulates;
a heat source unit including a second pump and a heat medium flow path of the second refrigerant-to-heat medium heat exchanger connected by a second heat medium pipe, and a part of a second heat medium circuit through which the second heat medium circulates;
A plurality of indoor units each having a load side heat exchanger;
A relay unit connected between the heat source unit and the indoor units,
The repeater is
a heat transfer device connected to each of the indoor units via an indoor-side forward heat medium piping and an indoor-side return heat medium piping, and switching between the first heat medium and the second heat medium as the heat medium supplied to each of the indoor units via the indoor-side forward heat medium piping and the indoor-side return heat medium piping;
The first heat medium piping is
A first heat medium pipe and a first return heat medium pipe are provided to connect the heat source unit and the relay unit,
The second heat medium piping is
an air conditioning apparatus having a second forward heat medium piping and a second return heat medium piping connecting the heat source unit and the relay unit; During full cooling operation,
the main refrigerant flow switching device, the first refrigerant flow switching device, and the second refrigerant flow switching device are switched so that the first refrigerant-to-heat medium heat exchanger and the second refrigerant-to-heat medium heat exchanger function as evaporators, and the on-off valve is opened to configure the refrigerant circuit;
During full heating operation,
the main refrigerant flow switching device, the first refrigerant flow switching device, and the second refrigerant flow switching device are switched so that the first refrigerant-to-heat medium heat exchanger and the second refrigerant-to-heat medium heat exchanger function as condensers, and the on-off valve is opened to configure the refrigerant circuit;
During cooling-dominant operation and heating-dominant operation,
2. The air-conditioning apparatus according to claim 1, wherein the main refrigerant flow switching device, the first refrigerant flow switching device, and the second refrigerant flow switching device are switched so that one of the first refrigerant-to-heat medium heat exchanger and the second refrigerant-to-heat medium heat exchanger functions as an evaporator and the other functions as a condenser, and the on-off valve is closed to configure the refrigerant circuit. The heat source unit is provided in a plurality of units,
A first outward header to which the first outward heat medium piping of each of the heat source machines is connected;
A first return header to which the first return heat medium piping of each of the heat source units is connected;
A second outgoing header to which the second outgoing heat medium piping of each of the heat source units is connected;
A second return header to which the second return heat medium piping of each of the heat source units is connected,
The air conditioning apparatus according to claim 1 or 2, wherein each of the heat source units is connected to the relay unit so as to be in parallel with each other via the first outbound header, the first return header, the second outbound header, and the second return header. The repeater is
The air-conditioning apparatus according to any one of claims 1 to 3, further comprising an expansion tank provided in each of the first heat medium piping and the second heat medium piping. The repeater is
an expansion tank provided in one of the first heat medium piping and the second heat medium piping;
The air conditioning apparatus according to any one of claims 1 to 3, wherein the first heat medium piping and the second heat medium piping are connected at least at one point by a connecting pipe having an inner diameter smaller than the first heat medium piping and the second heat medium piping.

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