Air conditioning device

Abstract

The invention provides an air conditioner capable of reliably unifying all outdoor units in a cold-hot switching mode or a cold-hot free mode. An air conditioning device according to one embodiment of the present invention is provided with a plurality of outdoor units and a plurality of indoor units, and is capable of selecting either a first refrigerant circuit state in which each indoor unit is capable of individually performing a cooling operation and a heating operation, or a second refrigerant circuit state in which each indoor unit is capable of individually performing a cooling operation and a heating operation. In the second refrigerant circuit state, each of the indoor units can perform a cooling operation or a heating operation at the same time. When either the first refrigerant circuit state or the second refrigerant circuit state is selected from one of the plurality of outdoor units, a state signal including information relating to the selected refrigerant circuit state is transmitted from the communication unit of the one outdoor unit to the communication unit of the other outdoor unit. And the other outdoor units receiving the state signal select the refrigerant loop state which is the same as the refrigerant loop state selected by the outdoor unit.

Description

Technical Field

[0001] The present invention relates to an air conditioning apparatus including a plurality of outdoor units, wherein the plurality of outdoor units are respectively connected to a plurality of indoor units via refrigerant pipes. Background Art

[0002] There is known an air conditioner that includes a plurality of indoor units and can switch between an operation mode in which all indoor units perform cooling or heating (hereinafter also referred to as a cooling and heating switching mode) and an operation mode in which each indoor unit selectively performs cooling or heating (hereinafter also referred to as a cooling and heating free mode). For example, Patent Document 1 discloses an air conditioner that can handle both the cooling and heating switching mode and the cooling and heating free mode with a single outdoor unit.

[0003] The air conditioning device of the free heating and cooling mode can selectively perform full heating operation, full cooling operation, heating-dominated operation, and cooling-dominated operation. Full heating operation is an operation mode in which all indoor units perform heating operation, and full cooling operation is an operation mode in which all indoor units perform cooling operation. Heating-dominated operation is an operation mode performed in the following case: indoor units performing cooling operation and indoor units performing heating operation are mixed, and the total value of the capacity required of the indoor units performing heating operation exceeds the total value of the capacity required of the indoor units performing cooling operation. Moreover, cooling-dominated operation is an operation mode performed in the following case: indoor units performing cooling operation and indoor units performing heating operation are mixed, and the total value of the capacity required of the indoor units performing cooling operation exceeds the total value of the capacity required of the indoor units performing heating operation.

[0004] The refrigerant circuit structure is different between the outdoor unit of the heat-cooling switching method and the outdoor unit of the heat-cooling free method. In the heat-cooling switching method, there are two connecting pipes (gas pipe and liquid pipe) connecting each indoor unit and outdoor unit, while in the heat-cooling free method, there are three connecting pipes, two gas pipes (high-pressure gas pipe and low-pressure gas pipe) and one liquid pipe, connecting each indoor unit and outdoor unit.

[0005] In each refrigerant pipe in the free-heat-cold mode, the refrigerant flows as follows according to the operation mode. First, the high-pressure gas pipe is a connecting pipe through which the high-pressure gas refrigerant discharged from the compressor flows during full heating operation, heating main operation, and cooling main operation. In addition, the low-pressure gas pipe is a connecting pipe through which the low-pressure gas refrigerant flowing out of the indoor heat exchanger functioning as an evaporator flows during full cooling operation and cooling main operation. Next, the liquid pipe is a refrigerant pipe through which the medium-pressure liquid refrigerant flowing out of the outdoor heat exchanger functioning as a condenser flows during full cooling operation and cooling main operation, and is a connecting pipe through which the medium-pressure liquid refrigerant flowing into the outdoor heat exchanger functioning as an evaporator flows during full heating operation and heating main operation.

[0006] The number of these connecting pipes used (the number of connections) is determined by the selected operating mode (cold-heat switching mode / cold-heat free mode), and the refrigerant circuit of the outdoor unit is switched between the refrigerant circuit for the cold-heat switching mode and the refrigerant circuit for the cold-heat free mode by a flow switching valve built into the outdoor unit.

[0007] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2008-111589 Summary of the invention

[0008] Technical problem to be solved by the invention In recent years, the development of air-conditioning devices that can cope with both the hot-cold switching mode and the hot-cold free mode has been continuously progressing. In such air-conditioning devices, all outdoor units need to be unified into either the hot-cold switching mode or the hot-cold free mode during operation. Usually, for outdoor units that can cope with both the hot-cold switching mode and the hot-cold free mode, it is assumed that a switching unit such as a DIP switch is provided in each outdoor unit, which switches the refrigerant circuit to either the hot-cold switching mode or the hot-cold free mode. When setting, the operator operates the switching unit for each outdoor unit. However, due to operating errors or forgetting to operate the above-mentioned switching unit, the air-conditioning device may be operated in a state where all outdoor units are not unified into either the hot-cold switching mode or the hot-cold free mode.

[0009] For example, if an outdoor unit of a hot / cold switching mode is mixed in an air conditioner operating in a hot / cold free mode, the high-pressure refrigerant flowing out of the outdoor unit of the hot / cold free mode flows into the gas pipe of the outdoor unit of the hot / cold switching mode, thereby increasing the low pressure and possibly exceeding the performance range of the compressor, and the high pressure also increases with the increase in the low pressure, and possibly causing the temperature of the refrigerant discharged from the compressor to exceed the usage range. In addition, if an outdoor unit of a hot / cold switching mode is mixed in an air conditioner operating in a hot / cold switching mode, the refrigerant and refrigeration oil may not return to the outdoor unit because the refrigerant piping is not connected to the low-pressure gas pipe of the outdoor unit of the hot / cold free mode, resulting in an excessive decrease in low pressure or insufficient refrigeration oil.

[0010] In view of the above situation, an object of the present invention is to provide an air conditioning device, in which, in an air conditioning device having multiple outdoor units capable of selecting a cold / hot switching mode and a cold / hot free mode, all outdoor units can be reliably unified into the cold / hot switching mode or the cold / hot free mode.

[0011] Technical solutions for solving technical problems An air conditioning device according to one embodiment of the present invention comprises: a plurality of outdoor units; a plurality of indoor units; and a plurality of connecting pipes, which connect each indoor unit to the plurality of outdoor units in parallel, wherein the air conditioning device can select either a first refrigerant circuit state or a second refrigerant circuit state, wherein in the first refrigerant circuit state, each indoor unit can independently perform cooling operation and heating operation, and in the second refrigerant circuit state, each indoor unit can simultaneously perform cooling operation or heating operation. The plurality of outdoor units each include a communication unit for communicating between the outdoor units, and a refrigerant circuit selection unit for selecting one of the first refrigerant circuit state and the second refrigerant circuit state. When either the first refrigerant circuit state or the second refrigerant circuit state is selected in one of the plurality of outdoor units, a state signal including information related to the selected refrigerant circuit state is transmitted from a communication unit of the one outdoor unit to communication units of other outdoor units, The other outdoor unit that has received the state signal selects the same refrigerant circuit state as the refrigerant circuit state selected by the one outdoor unit.

[0012] The refrigerant circuit selector may be a switching operation unit that selects one of the first refrigerant circuit state and the second refrigerant circuit state, and the state signal may include information on the refrigerant circuit state selected by the switching operation unit.

[0013] It may also be that, among the multiple outdoor units, one outdoor unit is set as a main outdoor unit, and the other outdoor units are set as sub-outdoor units that operate according to instructions of the main outdoor unit, and the sub-outdoor units select the same refrigerant circuit state as the refrigerant circuit state selected by the main outdoor unit based on the status signal sent from the main outdoor unit.

[0014] It may also be that, among the multiple outdoor units, the one outdoor unit is set as the main outdoor unit, and the other outdoor units are set as sub-outdoor units that operate according to instructions of the main outdoor unit, and the sub-outdoor unit selects the refrigerant circuit state included in the status signal sent from the main outdoor unit when the refrigerant circuit state selected by the switching operation unit of the sub-outdoor unit is different from the refrigerant circuit state included in the status signal sent from the main outdoor unit.

[0015] When starting or restarting power supply to the plurality of outdoor units, the main outdoor unit may confirm the refrigerant circuit state selected by the switching operation unit of the main outdoor unit, and include the confirmed refrigerant circuit state in the state signal and transmit it to the sub-outdoor unit.

[0016] When starting or restarting the supply of electric power to the sub-outdoor unit, the main outdoor unit may include the refrigerant circuit state selected by the main outdoor unit in the state signal and transmit the state signal to the sub-outdoor unit.

[0017] Alternatively, the plurality of outdoor units may include a compressor, an outdoor heat exchanger, a first flow path switching unit, and a second flow path switching unit, respectively, and a refrigerant inlet and outlet of the outdoor heat exchanger may be selectively connected to a refrigerant suction pipe or a refrigerant discharge pipe of the compressor via the first flow path switching unit. Alternatively, in the first refrigerant circuit state, three connecting pipes, namely, a first gas pipe and a second gas pipe selectively connected to the refrigerant suction pipe or the refrigerant discharge pipe via the second flow path switching unit, and a liquid pipe connected to another refrigerant inlet and outlet of the outdoor heat exchanger may be used as the plurality of connecting pipes, and in the second refrigerant circuit state, two connecting pipes, namely, the first gas pipe and the liquid pipe, may be used as the plurality of connecting pipes.

[0018] Effects of the Invention According to the present invention, in an air conditioning apparatus including a plurality of outdoor units capable of selecting between a cooling / heating switch mode and a cooling / heating free mode, all outdoor units can be reliably unified into the cooling / heating switch mode or the cooling / heating free mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a refrigerant circuit diagram showing a free-cooling and free-heating air-conditioning apparatus.

[0020] Figure 2 This is a refrigerant circuit diagram showing a cooling / heating switching air conditioner.

[0021] Figure 3 It is a block diagram showing the structure of the control device.

[0022] Figure 4 This is a refrigerant circuit diagram showing a situation in which a cooling / heating free air conditioning apparatus is mixed with a cooling / heating switching type outdoor unit.

[0023] Figure 5 This is a refrigerant circuit diagram showing a situation in which a free-heat and cooling type outdoor unit is mixed in a cooling / heating switchable type air conditioner.

[0024] Figure 6 This is a flowchart showing an example of a control procedure of each outdoor unit.

[0025] Figure 7 This is a flowchart showing an example of a control procedure of each outdoor unit when power is restored.

[0026] Figure 8 This is a flowchart showing another example of the control procedure of each outdoor unit when the power is restored.

[0027] Fig. 9 It is a refrigerant circuit diagram showing a modified example of the outdoor unit. DETAILED DESCRIPTION

[0028] Embodiments of the present invention will be described below with reference to the drawings.

[0029] The air conditioning device of this embodiment has multiple outdoor units and multiple indoor units, and can select an operation mode in which either cooling or heating is performed in all indoor units (cold-heat switching mode) and an operation mode in which either cooling or heating can be selectively performed in each indoor unit (cold-heat free mode).

[0030] Figure 1 1 is a refrigerant circuit diagram showing a configuration example of a cooling and heating free air conditioning device 10. Figure 2 1 is a refrigerant circuit diagram showing a configuration example of a cold / hot switching air conditioner 20. In this embodiment, an air conditioner is described by way of example in which three indoor units 8a, 8b, and 8c are connected in parallel to two outdoor units 2a and 2b.

[0031] When comparing the air conditioner 10 of the free cooling and heating mode and the air conditioner 20 of the cooling and heating switching mode, the outdoor unit 2a, the outdoor unit 2b and the indoor units 8a to 8c are the same, but the number of connection roots of the connecting pipes (high-pressure gas pipe 30, low-pressure gas pipe 31, liquid pipe 32) connecting the outdoor unit 2a, the outdoor unit 2b and the indoor units 8a to 8c is different. The air conditioner 10 and the air conditioner 20 of each mode are described below.

[0032] [Air conditioning device with free cooling and heating] First, refer to Figure 1 , the structure and operation example of the air conditioning device 10 of the cooling and heating free mode are explained.

[0033] like Figure 1 As shown, the air conditioner 10 includes: two outdoor units 2a and 2b; three indoor units 8a, 8b and 8c; three flow dividers 6a, 6b and 6c; and branching devices 70, 71 and 72. The outdoor units 2a and 2b, the indoor units 8a to 8c, the flow dividers 6a to 6c and the branching devices 70 to 72 are connected to each other through a high-pressure gas pipe 30 (first gas pipe), a high-pressure gas branch pipe 30a and a high-pressure gas branch pipe 30b, a low-pressure gas pipe 31 (second gas pipe), a low-pressure gas branch pipe 31a and a low-pressure gas branch pipe 31b, a liquid pipe 32, and a liquid branch pipe 32a and a liquid branch pipe 32b, thereby forming a refrigerant circuit of the air conditioner 10.

[0034] In the air-conditioning device 10, various operations can be performed according to the opening and closing states of various valve types possessed by the outdoor unit 2a, the outdoor unit 2b, and the diversion units 6a~6c, such as heating operation (all indoor units perform heating operation), heating-main operation (the total value of the capacities required of the indoor units performing heating operation exceeds the total value of the capacities required of the indoor units performing cooling operation), cooling operation (all indoor units perform cooling operation), cooling-main operation (the total value of the capacities required of the indoor units performing cooling operation exceeds the total value of the capacities required of the indoor units performing heating operation), etc.

[0035] (Outdoor unit) The outdoor unit 2a and the outdoor unit 2b have the same structure, and the same reference numerals are given to the corresponding parts. In the following description, only the structure of the outdoor unit 2a will be described, and the description of the outdoor unit 2b will be omitted.

[0036] The outdoor unit 2a includes: a compressor 21; a first three-way valve 22 and a second three-way valve 23 as a first flow path switching unit; a first outdoor heat exchanger 24; a second outdoor heat exchanger 25; an outdoor fan 26; a liquid storage tank 27; a four-way valve 29 as a second flow path switching unit; a first outdoor expansion valve 40 connected to the first outdoor heat exchanger 24; and a second outdoor expansion valve 41 connected to the second outdoor heat exchanger 25.

[0037] The compressor 21 is a variable capacity compressor that can change the operating capacity by being driven by a motor (not shown) whose rotation speed is controlled by an inverter. The discharge side of the compressor 21 is connected to the port a of the first three-way valve 22 and the port d of the second three-way valve 23 through the discharge pipe 28, and is connected to the port g of the four-way valve 29 through the discharge pipe 28 and the outdoor unit high-pressure gas pipe 33. The discharge pipe 28 is a refrigerant pipe connecting the discharge side of the compressor 21 and the connection point A, and the outdoor unit high-pressure gas pipe 33 is a refrigerant pipe connecting the connection point A and the stop valve 44. In addition, the suction side of the compressor 21 is connected to the outflow side of the accumulator 27 through the suction pipe 42, and the inflow side of the accumulator 27 is connected to the stop valve 45 through the outdoor unit low-pressure gas pipe 34.

[0038] The first three-way valve 22 and the second three-way valve 23 are valves for switching the flow direction of the refrigerant in the refrigerant circuit. The first three-way valve 22 has three ports a, b, and c, respectively, and the second three-way valve 23 has three ports d, e, and f, respectively. In the first three-way valve 22, the refrigerant pipe connected to the port a is connected to the discharge pipe 28 and the outdoor unit high-pressure gas pipe 33 at the connection point A. In addition, the port b and one end (one refrigerant inlet and outlet) of the first outdoor heat exchanger 24 are connected by the refrigerant pipe, and the refrigerant pipe connected to the port c is connected to the outdoor unit low-pressure gas pipe 34 at the connection point D.

[0039] In the second three-way valve 23, the refrigerant pipe connected to the port d is connected to the refrigerant pipe connected to the discharge pipe 28 and the outdoor unit high-pressure gas pipe 33 at the connection point A. In addition, the port e is connected to one end (one refrigerant inlet and outlet) of the second outdoor heat exchanger 25 by the refrigerant pipe, and the refrigerant pipe connected to the port f is connected to the refrigerant pipe connected to the port c of the first three-way valve 22 at the connection point C.

[0040] The four-way valve 29 is a valve that changes the control mode according to whether the outdoor unit 2a or the outdoor unit 2b is set to the free mode of cold and heat or the mode of cold and heat switching, and has four ports g, h, k, and m. As described above, port g is connected to the outdoor unit high-pressure gas pipe 33, and port h is connected to the stop valve 44. Port k is closed, and port m is connected to the connection point E of the outdoor unit low-pressure gas pipe 34 through the refrigerant piping. The details will be described later. When the outdoor unit 2a or the outdoor unit 2b is set to the free mode of cold and heat, the four-way valve 29 is switched so that the refrigerant flows from the outdoor unit high-pressure gas pipe 33 to the high-pressure gas branch pipe 30a and the high-pressure gas branch pipe 30b respectively. In addition, when the outdoor unit 2a and the outdoor unit 2b are set to the cold and hot switching mode, during the heating operation, the four-way valve 29 is switched to allow the refrigerant to flow from the outdoor unit high-pressure gas pipe 33 to the high-pressure gas branch pipe 30a and the high-pressure gas branch pipe 30b respectively; during the cooling operation, the four-way valve 29 is switched to allow the refrigerant to flow from the low-pressure gas branch pipe 31a and the low-pressure gas branch pipe 31b to the outdoor unit low-pressure gas pipe 34 respectively.

[0041] As described above, one end (one refrigerant inlet and outlet) of the first outdoor heat exchanger 24 is connected to the port b of the first three-way valve 22 via the refrigerant piping, and the other end (the other refrigerant inlet and outlet) is connected to one port of the first outdoor expansion valve 40 via the refrigerant piping. The other port of the first outdoor expansion valve 40 is connected to the stop valve 46 via the outdoor unit liquid pipe 35. In addition, one end (one refrigerant inlet and outlet) of the second outdoor heat exchanger 25 is connected to the port e of the second three-way valve 23 via the refrigerant piping as described above, and the other end (the other refrigerant inlet and outlet) is connected to one port of the second outdoor expansion valve 41 via the refrigerant piping. The other port of the second outdoor expansion valve 41 is connected to the connection point B of the outdoor unit liquid pipe 35 via the refrigerant piping.

[0042] The inflow side of the accumulator 27 is connected to the outdoor unit low-pressure gas pipe 34, and the outflow side is connected to the suction side of the compressor 21 through the suction pipe 42. The accumulator 27 separates the inflowing refrigerant into gas refrigerant and liquid refrigerant, so that the compressor 21a only sucks in the gas refrigerant. The outdoor fan 26 is rotated by a fan motor (not shown), thereby taking in external air into the outdoor unit 2a, and after the refrigerant and the external air perform heat exchange in the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25, the heat-exchanged external air is discharged to the outside of the outdoor unit 2a.

[0043] In addition to the above-described structure, various sensors are provided in the outdoor unit 2a. Figure 1As shown, a high pressure sensor 50 for detecting the pressure of the refrigerant discharged from the compressor 21 and a discharge temperature sensor 53 for detecting the temperature of the refrigerant discharged from the compressor 21 are provided in the discharge piping 28. In addition, a low pressure sensor 51 for detecting the pressure of the refrigerant sucked into the compressor 21 and a suction temperature sensor 54 for detecting the temperature of the refrigerant sucked into the compressor 21 are provided between the connection point D of the outdoor unit low pressure gas pipe 34 and the inflow side of the accumulator 27a.

[0044] A first heat exchange temperature sensor 56 for detecting the temperature of the refrigerant flowing out of or flowing into the first outdoor heat exchanger 24 is provided in the refrigerant piping connecting the port b of the first three-way valve 22 and the first outdoor heat exchanger 24. In addition, a second heat exchange temperature sensor 57 for detecting the temperature of the refrigerant flowing out of or flowing into the second outdoor heat exchanger 25 is provided in the refrigerant piping connecting the port e of the second three-way valve 23 and the second outdoor heat exchanger 25. Furthermore, the outdoor unit 2a is provided with an outdoor air temperature sensor 58 for detecting the temperature of the outdoor air flowing into the outdoor unit 2a, that is, the outdoor air temperature.

[0045] (Indoor unit) The three indoor units 8a to 8c include an indoor heat exchanger 81, an indoor expansion valve 82, and an indoor fan 83. The indoor units 8a to 8c all have the same structure, so in the following description, only the structure of the indoor unit 8a will be described, and the description of the other indoor units 8b and 8c will be omitted.

[0046] One end (one refrigerant inlet and outlet) of the indoor heat exchanger 81 is connected to one port of the indoor expansion valve 82 through a refrigerant pipe, and the other end (the other refrigerant inlet and outlet) is connected to the flow dividing unit 6a described later through a refrigerant pipe 87. The indoor heat exchanger 81 functions as an evaporator when the indoor unit 8a performs cooling operation, and functions as a condenser when the indoor unit 8a performs heating operation.

[0047] As described above, one port of the indoor expansion valve 82 is connected to the indoor heat exchanger 81, and the other port is connected to the liquid pipe 32. When the indoor heat exchanger 81 functions as an evaporator, the opening of the indoor expansion valve 82 is adjusted according to the required cooling capacity, and when the indoor heat exchanger 81 functions as a condenser, the opening of the indoor expansion valve 82 is adjusted according to the required heating capacity.

[0048] The indoor fan 83 is rotated by a fan motor (not shown) to take indoor air into the indoor unit 8a, and after the refrigerant and the indoor air exchange heat in the indoor heat exchanger 81, the heat-exchanged air is supplied to the room.

[0049] In addition to the above-described configuration, various sensors are provided in the indoor unit 8a. A refrigerant temperature sensor 84 for detecting the temperature of the refrigerant is provided in the refrigerant piping on the indoor expansion valve 82 side of the indoor heat exchanger 81, and a refrigerant temperature sensor 85 for detecting the temperature of the refrigerant is provided in the refrigerant piping on the branch unit 6a side of the indoor heat exchanger 81. In addition, a room temperature sensor 86 for detecting the temperature of the indoor air flowing into the indoor unit 8a, that is, the indoor temperature, is provided near the indoor air intake port (not shown) of the indoor unit 8a.

[0050] (Diversion unit) The air conditioner 10 includes three flow dividers 6a to 6c corresponding to the three indoor units 8a to 8c. The flow dividers 6a to 6c include first solenoid valves 61a to 61c, second solenoid valves 62a to 62c, first flow dividers 63a to 63c, and second flow dividers 64a to 64c. It should be noted that since the structures of the flow dividers 6a to 6c are all the same, only the structure of the flow divider 6a will be described in the following description, and the description of the other flow dividers 6b and 6c will be omitted.

[0051] One end of the first flow dividing pipe 63a is connected to the high-pressure gas pipe 30, and one end of the second flow dividing pipe 64a is connected to the low-pressure gas pipe 31. In addition, the other end of the first flow dividing pipe 63a and the other end of the second flow dividing pipe 64a are connected to each other, and the connection part is connected to the indoor heat exchanger 81 through the refrigerant pipe 87. The first solenoid valve 61a is provided in the first flow dividing pipe 63a, and the second solenoid valve 62a is provided in the second flow dividing pipe 64a. By opening and closing the first solenoid valve 61a and the second solenoid valve 62a, the flow path of the refrigerant in the refrigerant circuit can be switched so that the indoor heat exchanger 81 of the indoor unit 8a corresponding to the flow dividing unit 6a is connected to the discharge side (high-pressure gas pipe 30 side) or the suction side (low-pressure gas pipe 31 side) of the compressor 21.

[0052] (Connecting pipes) use Figure 1 The connection status of the outdoor unit 2a, outdoor unit 2b, indoor unit 8a~8c and diversion units 6a~6c described above and the high-pressure gas pipe 30, high-pressure gas branch pipe 30a, high-pressure gas branch pipe 30b, low-pressure gas pipe 31, low-pressure gas branch pipe 31a, low-pressure gas branch pipe 31b, liquid pipe 32, liquid branch pipe 32a, liquid branch pipe 32b and branch devices 70, branch devices 71, and branch devices 72 is described.

[0053] One end of the high-pressure gas branch pipe 30a and one end of the high-pressure gas branch pipe 30b are connected to the stop valve 44 of each outdoor unit 2a and 2b, respectively, and the other ends of the high-pressure gas branch pipe 30a and the high-pressure gas branch pipe 30b are connected to the branching device 70. One end of the high-pressure gas pipe 30 is connected to the branching device 70, and the other end of the high-pressure gas pipe 30 is branched and connected to the first branching pipes 63a to 63c of the branching units 6a to 6c.

[0054] One end of the low-pressure gas branch pipe 31a and the low-pressure gas branch pipe 31b are connected to the stop valve 45 of each outdoor unit 2a and the outdoor unit 2b, respectively, and the other ends of the low-pressure gas branch pipe 31a and the low-pressure gas branch pipe 31b are connected to the branching device 71. One end of the low-pressure gas pipe 31 is connected to the branching device 71, and the other end of the low-pressure gas pipe 31 is branched and connected to the second branching pipes 64a to 64c of the branching units 6a to 6c.

[0055] One end of the liquid branch pipe 32a and the liquid branch pipe 32b are connected to the stop valve 46 of each outdoor unit 2a and the outdoor unit 2b, respectively, and the other ends of the liquid branch pipe 32a and the liquid branch pipe 32b are connected to the branching device 72. One end of the liquid pipe 32 is connected to the branching device 72, and the other end of the liquid pipe 32 is branched and connected to the indoor expansion valve 82 of the indoor unit 8a to 8c through the refrigerant piping.

[0056] Furthermore, the indoor heat exchangers 81 of the indoor units 8a to 8c and the connection points of the first flow branching pipes 63a to 63c and the second flow branching pipes 64a to 64c in the flow branching units 6a to 6c are connected via refrigerant pipes 87, respectively.

[0057] The connections described above constitute a refrigerant circuit of the air conditioning device 10, and a refrigeration cycle is established by causing the refrigerant to flow in the refrigerant circuit. Figure 1 As shown in FIG. 1 , the state of the refrigerant circuit in which each of the indoor units 8a to 8c can independently perform cooling operation or heating operation is also referred to as a "first refrigerant circuit state."

[0058] (Control device) The outdoor unit 2a and the outdoor unit 2b are provided with control devices 110a and 110b, respectively. Figure 3 110a and 110b are block diagrams showing the configuration of the control devices 110a and 110b. The configurations of the control devices 110a and 110b are basically the same, so in the following description, only the configuration of the control device 110a will be described, and the description of the control device 110b will be omitted.

[0059] The control device 110a is mounted on a control substrate (not shown) stored in an electrical component box (not shown), and includes a CPU 111a, a storage unit 112a, a refrigerant circuit selection unit 113a, and a communication unit 114a. The CPU 111a receives the detection signals of the above-mentioned sensors from the outdoor unit 2a, and receives the control signals output from the indoor units 8a to 8c via the communication unit 113a. The CPU 111a performs various controls such as drive control of the compressor 21, switching control of the first three-way valve 22, the second three-way valve 23, and the four-way valve 29, and opening control of the first outdoor expansion valve 40 and the second outdoor expansion valve 41 based on the received detection signals and control signals. It should be noted that the opening and closing control of the first electromagnetic valve 61a to 61c and the second electromagnetic valve 62a to 62c in the diverter units 6a to 6c is performed by the control device (not shown) of the indoor unit 6a to 6c corresponding to the diverter units 6a to 6c.

[0060] The storage unit 112a is composed of ROM and RAM, and stores the control program of the outdoor unit 2a and the detection values ​​corresponding to the detection signals from each sensor. The storage unit 112a stores the control program for executing the operation mode of the cooling and heating free mode and the control program for executing the cooling and heating switching mode ( Figure 2 ) operation mode control program.

[0061] The refrigerant circuit selection unit 113a is used to select any one of the operation mode of the cold and hot free mode and the operation mode of the cold and hot switching mode of the outdoor unit 2a. If the cold and hot free mode is selected by the refrigerant circuit selection unit 113a, the CPU 111a sets the refrigerant circuit state to the first refrigerant circuit state and executes the control program of the operation mode of the cold and hot free mode. If the cold and hot switching mode is selected by the refrigerant circuit selection unit 113a, the CPU 111a sets the refrigerant circuit state to the second refrigerant circuit state and executes the control program of the operation mode of the cold and hot switching mode.

[0062] In the present embodiment, the refrigerant circuit selection unit 113a is a hard switch (switching operation unit) such as a dip switch or a toggle switch that is stored in the above-mentioned electrical component box and switched by an operator. Alternatively, the refrigerant circuit selection unit 113a may be a soft switch that is switched according to an input signal from an electronic device such as a PC. It should be noted that regarding the switching of the refrigerant circuit state, there is a case where the CPU 111a operates in response to an instruction from another outdoor unit (in the present embodiment, the outdoor unit 2b) (details will be described later).

[0063] The communication unit 114 a is an interface for performing communication between the outdoor unit 2 a and the indoor units 8 a to 8 c and communication between the outdoor unit 2 a and the outdoor unit 2 b (communication unit 114 b ), and includes, for example, a short-distance wireless communication module.

[0064] It should be noted that the structure of the control device 110b is the same as that of the control device 110a as described above, and the suffix of the number assigned to the structural elements (devices, components) of the control device 110a is changed from a to b to become the structural elements of the control device 110b corresponding to the structural elements of the control device 110a.

[0065] Next, use Figure 1 The operation of the cooling and heating free air conditioning device 10 will be described.

[0066] (Full heating operation) like Figure 1 As shown, when all indoor units 8a to 8c are in heating operation, the first three-way valve 22 of each outdoor unit 2a and outdoor unit 2b is switched so that the port b and the port c are connected (in Figure 1 The first outdoor heat exchanger 24 functions as an evaporator, and the port e and the port f of the second three-way valve 23 of each outdoor unit 2a and the outdoor unit 2b are connected by switching (indicated by a solid line in FIG. Figure 1 In the figure, the second outdoor heat exchanger 25 is caused to function as an evaporator. In addition, the four-way valve 29 of each outdoor unit 2a and the outdoor unit 2b is switched so that the port g is connected to the port h and the port k is connected to the port m (in the figure). Figure 1 Indicated by solid lines).

[0067] In the indoor units 8a to 8c, the first solenoid valves 61a to 61c of the corresponding flow dividers 6a to 6c are opened to allow the refrigerant to flow through the first flow dividers 63a to 63c, and the second solenoid valves 62a to 62c are closed to cut off the second flow dividers 64a to 64c. Thus, all the indoor heat exchangers 81 of the indoor units 8a to 8c function as condensers.

[0068] The high-pressure refrigerant discharged from the compressor 21 of the outdoor unit 2a flows through the discharge pipe 28 and the outdoor unit high-pressure gas pipe 33, and flows into the high-pressure gas branch pipe 30a via the stop valve 44. Similarly, the high-pressure refrigerant discharged from the compressor 21 of the outdoor unit 2b flows through the discharge pipe 28 and the outdoor unit high-pressure gas pipe 33, and flows into the high-pressure gas branch pipe 30b via the stop valve 44. The high-pressure refrigerants flowing into the high-pressure gas branch pipes 30a and 30b merge at the branch unit 70 and flow into the high-pressure gas pipe 30, and then flow into the branch units 6a to 6c separately from the high-pressure gas pipe 30.

[0069] The high-pressure refrigerant having flowed into the branching units 6a to 6c flows through the first branching pipes 63a to 63c having the opened first electromagnetic valves 61a to 61c, flows out of the branching units 6a to 6c, and flows into the indoor units 8a to 8c corresponding to the branching units 6a to 6c.

[0070] The high-pressure refrigerant flowing into each indoor unit 8a to 8c flows into the indoor heat exchanger 81, exchanges heat with the indoor air and condenses. As a result, the indoor air is heated, and the room in which the indoor units 8a to 8c are installed is heated. The high-pressure refrigerant flowing out of the indoor heat exchanger 81 is decompressed by passing through the indoor expansion valve 82. The opening degree of the indoor expansion valve 82 is determined according to the degree of subcooling of the refrigerant at the refrigerant outlet of the indoor heat exchanger 81. The degree of subcooling of the refrigerant is obtained, for example, by subtracting the refrigerant temperature at the refrigerant outlet of the indoor heat exchanger 81 detected by the refrigerant temperature sensor 84 from the high-pressure saturation temperature (equivalent to the condensation temperature in the indoor heat exchanger 81) calculated based on the pressure detected by the high-pressure sensor 50 of the outdoor unit 2a or the outdoor unit 2b.

[0071] The intermediate pressure refrigerant flowing out of each indoor unit 8a to 8c flows into the liquid pipe 32, merges in the liquid pipe 32, and flows into the branching device 72. The intermediate pressure refrigerant branched from the branching device 72 to the liquid branch pipe 32a and the liquid branch pipe 32b flows into each outdoor unit 2a and the outdoor unit 2b via the stop valve 46. The intermediate pressure refrigerant flowing into each outdoor unit 2a and the outdoor unit 2b flows in the outdoor unit liquid pipe 35, branches at the connection point B, passes through the first outdoor expansion valve 40a and the second outdoor expansion valve 41, is decompressed, and becomes a low-pressure refrigerant.

[0072] The opening degree of the first outdoor expansion valve 40 is determined according to the superheat of the refrigerant at the refrigerant outlet of the first outdoor heat exchanger 24. In addition, the opening degree of the second outdoor expansion valve 41 is determined according to the superheat of the refrigerant at the refrigerant outlet of the second outdoor heat exchanger 25. The superheat of the refrigerant is obtained, for example, by subtracting the low-pressure saturation temperature (equivalent to the evaporation temperature in the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25) calculated based on the pressure detected by the low-pressure sensor 51 of the outdoor unit 2a and the outdoor unit 2b from the refrigerant temperature at the refrigerant outlet of the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 detected by the first heat exchange temperature sensor 56 and the second heat exchange temperature sensor 57.

[0073] The low-pressure refrigerant after being decompressed by the first outdoor expansion valve 40 and the second outdoor expansion valve 41 flows into the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25, exchanges heat with the external air and evaporates. Then, the low-pressure refrigerant flowing out of the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 merges at the connection point C through the first three-way valve 22 and the second three-way valve 23, and is sucked into the compressor 21 through the connection point D and the accumulator 27 to be compressed again.

[0074] (Full refrigeration operation) Next, the case where all the indoor units 8a to 8c are in cooling operation will be described. When all the indoor units 8a to 8c are in cooling operation, the first three-way valve 22 of each outdoor unit 2a and outdoor unit 2b is switched so that the port a and the port b are connected (in Figure 1 The first outdoor heat exchanger 24 functions as a condenser, and the first outdoor heat exchanger 24 is switched so that the port d and the port e of the second three-way valve 23 are connected (indicated by a dotted line in FIG. Figure 1 In the figure, the second outdoor heat exchanger 25 is made to function as a condenser. In addition, the four-way valve 29 of each outdoor unit 2a and the outdoor unit 2b is switched so that the port g is connected to the port h and the port k is connected to the port m (in the figure). Figure 1 Indicated by solid lines).

[0075] In the indoor units 8a to 8c, the first solenoid valves 61a to 61c of the corresponding flow dividing units 6a to 6c are closed, the first flow dividing pipes 63a to 63c are cut off, and the second solenoid valves 62a to 62c are opened to allow the refrigerant to flow through the second flow dividing pipes 64a to 64c. Thus, all the indoor heat exchangers 81 of the indoor units 8a to 8c function as evaporators.

[0076] The high-pressure refrigerant discharged from the compressor 21 of each outdoor unit 2a, 2b is divided to the first three-way valve 22 side, the second three-way valve 23 side and the high-pressure gas pipe 30 side. The refrigerant flowing on the first three-way valve 22 and the second three-way valve 23 side flows into the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25, and condenses by heat exchange with the external air. Since the first solenoid valves 61a~61c of each diversion unit 6a~6c are closed, the refrigerant flowing to the high-pressure gas pipe 30 side does not flow into the indoor units 8a~8c, but stays in the outdoor unit high-pressure gas pipe 33, the high-pressure gas branch pipes 30a, 30b and the high-pressure gas pipe 30.

[0077] Here, when the refrigeration capacity required of each indoor unit 8a to 8c becomes greater than a given value, as described above, if the refrigerant is retained in the outdoor unit high-pressure gas pipe 33 and the high-pressure gas pipe 30, it may be impossible to circulate the refrigerant circuit in the amount required to exert the required refrigeration capacity. In this case, the four-way valve 29 is switched so that the port g is connected to the port k and the port h is connected to the port m (in Figure 1 As a result, the refrigerant is retained only in the outdoor unit high-pressure gas pipe 33 (the refrigerant is not retained in the high-pressure gas branch pipe 30a, the high-pressure gas branch pipe 30b and the high-pressure gas pipe 30), so the amount of retained refrigerant is reduced and the amount of refrigerant circulating in the refrigerant circuit is increased. It should be noted that for the four-way valve 29 during full cooling operation, if the refrigeration capacity required for each indoor unit a to 8c during full cooling operation becomes greater than a predetermined given value, then Figure 1 The state shown by the solid line can be switched to the state shown by the dotted line. In addition, if the cooling capacity required for each indoor unit a to 8c at the start of the full cooling operation is above a predetermined given value, Figure 1 The state shown by the solid line can be switched to the state shown by the dotted line.

[0078] The refrigerant condensed in the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 of the outdoor unit 2a flows through the first outdoor expansion valve 40 and the second outdoor expansion valve 41 set to the fully open state by the control device 110a, and flows into the liquid branch pipe 32a via the stop valve 46. Similarly, the refrigerant condensed in the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 of the outdoor unit 2b flows through the first outdoor expansion valve 40 and the second outdoor expansion valve 41 set to the fully open state by the control device 110b, and flows into the liquid branch pipe 32b via the stop valve 46. The intermediate pressure refrigerant flowing into the liquid branch pipes 32a and 32b merges at the branch unit 72 and flows in the liquid pipe 32, and is divided from the liquid pipe 32 and flows into each indoor unit 8a to 8c.

[0079] The intermediate pressure refrigerant flowing into each indoor unit 8a to 8c is decompressed by the indoor expansion valve 82 to become a low-pressure refrigerant, and flows into the indoor heat exchanger 81. The low-pressure refrigerant flowing into the indoor heat exchanger 81 exchanges heat with the indoor air and evaporates, thereby cooling the room where the indoor units 8a to 8c are installed. Here, the refrigerant superheat at the outlet of the indoor heat exchanger 81 as an evaporator is obtained based on the refrigerant temperature detected by the refrigerant temperature sensor 84 and the refrigerant temperature sensor 85, and the opening degree of the indoor expansion valve 82 is determined based on the refrigerant superheat.

[0080] The low-pressure refrigerant flowing out of the indoor heat exchanger 81 flows into the branching units 6a to 6e, flows through the second branching pipes 64a to 64b with the opened second electromagnetic valves 62a to 62c, and flows into the low-pressure gas pipe 31. Then, the low-pressure refrigerant flowing into the low-pressure gas pipe 31 from each branching unit 6a to 6c and converging in the low-pressure gas pipe 31 is divided by the branch pipe 71 and flows to the low-pressure gas branch pipe 31a and the low-pressure gas branch pipe 31b and flows into each outdoor unit 2a and the outdoor unit 2b. The low-pressure refrigerant flowing into each outdoor unit 2a and the outdoor unit 2b passes through the outdoor unit low-pressure gas pipe 34, is sucked into the compressor 21 via the accumulator 27, and is compressed again.

[0081] [Operation of air conditioner when cooling operation and heating operation are mixed in indoor unit] Next, the case where the indoor units 8a to 8c are in a mixed state of cooling operation and heating operation will be described. In the case where the indoor units 8a to 8c are in a mixed state of cooling operation and heating operation, the state of the refrigerant circuit is determined based on the comparison result of the total value of the cooling capacity required by the indoor units in the cooling operation and the total value of the heating capacity required by the indoor units in the heating operation. In the present embodiment, as an example, the indoor unit 8a and the indoor unit 8b perform heating operation / the indoor unit 8c performs cooling operation. When the heating capacity required by the two indoor units 8a and the indoor unit 8b performing heating operation is greater than the cooling capacity required by the one indoor unit 8c performing cooling operation, the heating main operation is performed, and the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 respectively function as evaporators; the indoor unit 8a and the indoor unit 8b perform cooling operation / the indoor unit 8c performs heating operation. When the cooling capacity required by the two indoor units 8a and the indoor unit 8b performing cooling operation is greater than the heating capacity required by the one indoor unit 8c performing heating operation, the cooling main operation is performed, and the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 respectively function as condensers.

[0082] (Heating main operation) In the heating main operation, in each of the outdoor units 2a and 2b, the first three-way valve 22 is switched so that the port b communicates with the port c (in Figure 1 The second three-way valve 23 is switched so that the port e is connected to the port f (indicated by a solid line in FIG. Figure 1 In addition, the four-way valve 29 is switched so that the port g is communicated with the port h and the port k is communicated with the port m (in Figure 1 Thus, both the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 function as evaporators.

[0083] In addition, the first solenoid valves 61a and 61b of the two flow dividers 6a and 6b corresponding to the two indoor units 8a and 8b performing the heating operation are opened to connect the first flow dividers 63a and 63b, and the second solenoid valves 62a and 62b are closed to cut off the second flow dividers 64a and 64b. As a result, the indoor heat exchangers 81 of the two indoor units 8a and 8b become condensers.

[0084] On the other hand, the first electromagnetic valve 61c of the flow dividing unit 6c corresponding to the indoor unit 8c performing cooling operation is closed to cut off the first flow dividing pipe 63c, and the second electromagnetic valve 62c is opened to connect the second flow dividing pipe 64c. Thus, the indoor heat exchanger 81 of the indoor unit 8c becomes an evaporator.

[0085] The high-pressure refrigerant discharged from the compressor 21 of each outdoor unit 2a, 2b flows in the high-pressure gas pipe 30 and flows into the branch unit 6a, 6b separately. The high-pressure refrigerant flowing into the branch unit 6a, 6b flows in the first branch pipe 63a, 63b having the first electromagnetic valve 61a, 61b opened, flows out of the branch unit 6a, 6b, and flows into the corresponding indoor unit 8a, 8b.

[0086] The high-pressure refrigerant flowing into the indoor unit 8a, 8b flows into the indoor heat exchanger 81, exchanges heat with the indoor air and condenses, thereby heating the room where the indoor unit 8a, 8b is installed. The high-pressure refrigerant condensed in the indoor heat exchanger 81 is decompressed by the indoor expansion valve 82 to become an intermediate-pressure refrigerant. Here, the control unit of the indoor unit 8a, 8b calculates the refrigerant subcooling degree in the indoor heat exchanger 81 as a condenser based on the refrigerant temperature detected by the refrigerant temperature sensor 84 and the high-pressure saturation temperature obtained from the outdoor unit 2a, 2b, and determines the opening degree of the indoor expansion valve 82 based on the refrigerant subcooling degree.

[0087] The intermediate pressure refrigerant flowing out of the indoor unit 8a and the indoor unit 8b flows into the liquid pipe 32. Then, a part of the intermediate pressure refrigerant converging in the liquid pipe 32 flows into the outdoor unit 2a and the outdoor unit 2b through the branch pipe 72, the liquid branch pipe 32a, and the liquid branch pipe 32b, and the remaining part flows in the liquid pipe 32 and flows into the indoor unit 8c.

[0088] The intermediate-pressure refrigerant flowing into the outdoor unit 2a and the outdoor unit 2b is decompressed when passing through the first outdoor expansion valve 40 and the second outdoor expansion valve 41, which are set to the opening corresponding to the superheat of the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25, and becomes a low-pressure refrigerant, and flows into the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25. The low-pressure refrigerant flowing into the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 exchanges heat with the external air and evaporates. Then, the low-pressure refrigerant flowing out of the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 passes through the first three-way valve 22 and the second three-way valve 23, and is sucked into the compressor 21 through the accumulator 27 and compressed again.

[0089] On the other hand, the intermediate pressure refrigerant flowing into the indoor unit 8c is decompressed by the indoor expansion valve 82 to become a low-pressure refrigerant, and flows into the indoor heat exchanger 81. The low-pressure refrigerant flowing into the indoor heat exchanger 81 exchanges heat with the indoor air and evaporates, thereby cooling the room in which the indoor unit 8c is installed. Here, the refrigerant superheat in the indoor heat exchanger 81 as an evaporator is obtained based on the refrigerant temperature detected by the refrigerant temperature sensor 84 and the refrigerant temperature sensor 85, and the opening degree of the indoor expansion valve 82 of the indoor unit 8c is determined based on the refrigerant superheat.

[0090] The low-pressure refrigerant flowing out of the indoor heat exchanger 8c flows into the flow divider unit 6c, flows through the second flow divider pipe 64c having the opened second solenoid valve 62c, and flows into the low-pressure gas pipe 31. The low-pressure refrigerant flowing into the low-pressure gas pipe 31 flows into the outdoor unit 2a and the outdoor unit 2b through the branch pipe 71, the low-pressure gas branch pipe 31a, and the low-pressure gas branch pipe 31b, and is sucked into the compressor 21 through the accumulator 27 and compressed again.

[0091] (Refrigeration main operation) In the cooling main operation, in each of the outdoor units 2a and 2b, the first three-way valve 22 is switched so that the port a communicates with the port b (in Figure 1 The second three-way valve 23 is switched so that port d is connected to port e (indicated by dashed lines in FIG. Figure 1 In addition, the four-way valve 29 is switched so that the port g is communicated with the port h and the port k is communicated with the port m (in FIG. Figure 1 Thus, both the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 function as condensers.

[0092] In addition, the electromagnetic valves 61a and 61b of the two flow dividers 6a and 6b corresponding to the two indoor units 8a and 8b performing cooling operation are closed to cut off the first flow divider pipes 63a and 63b, and the second electromagnetic valves 62a and 62b are opened to connect the second flow divider pipes 64a and 64b. Thus, the indoor heat exchangers 81 of the two indoor units 8a and 8b become evaporators.

[0093] On the other hand, the electromagnetic valve 61c of the flow dividing unit 6c corresponding to the indoor unit 8c performing the heating operation is opened to connect the first flow dividing pipe 63c, and the second electromagnetic valve 62c is closed to cut off the second flow dividing pipe 64c. Thus, the indoor heat exchanger 81 of the indoor unit 8c becomes a condenser.

[0094] The high-pressure refrigerant discharged from the compressor 21 of each outdoor unit 2a, 2b is divided to the first three-way valve 22 side, the second three-way valve 23 side and the high-pressure gas pipe 30 side. The high-pressure refrigerant that has passed through the first three-way valve 22 and the second three-way valve 23 flows into the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25, and is condensed by heat exchange with the external air. The refrigerant condensed in the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 passes through the first outdoor expansion valve 40 and the second outdoor expansion valve 41, which are set to an opening corresponding to the difference between the discharge pressure of the compressor 21 and the hydraulic pressure by the control devices 110a, 110b, and becomes a refrigerant of intermediate pressure, flows in the liquid pipe 32, and flows into the indoor unit 8a and the indoor unit 8b separately.

[0095] The intermediate pressure refrigerant flowing into the indoor unit 8a, 8b is decompressed by the indoor expansion valve 82 to become a low-pressure refrigerant, and flows into the indoor heat exchanger 81. The low-pressure refrigerant flowing into the indoor heat exchanger 81 exchanges heat with the indoor air and evaporates, thereby cooling the room where the indoor unit 8a, 8b is installed. Here, the refrigerant superheat in the indoor heat exchanger 81 as an evaporator is obtained based on the refrigerant temperature detected by the refrigerant temperature sensor 84, the refrigerant temperature sensor 85, and the opening degree of the indoor expansion valve 82 is determined based on the refrigerant superheat.

[0096] The low-pressure refrigerant flowing out of the indoor heat exchanger 81 of the indoor unit 8a, 8b flows into the branch unit 6a, 6b, flows through the second branch pipe 64a, 64b with the opened second electromagnetic valve 62a, 62b, and flows into the low-pressure gas pipe 31. Then, the low-pressure refrigerant flowing into the low-pressure gas pipe 31 from each branch unit 6a, 6b merges in the low-pressure gas pipe 31, flows into the outdoor unit 2a, 2b through the branch pipe 71, the low-pressure gas branch pipe 31a, 31b, and is sucked into the compressor 21 through the accumulator 27 to be compressed again.

[0097] On the other hand, the high-pressure refrigerant flowing in the high-pressure gas pipe 30 and flowing into the flow dividing unit 6c flows in the first flow dividing pipe 63c having the opened electromagnetic valve 61c and flows into the indoor unit 8c. The high-pressure refrigerant flowing into the indoor unit 8c flows into the indoor heat exchanger 81, exchanges heat with the indoor air and condenses, thereby heating the room in which the indoor unit 8c is installed. The high-pressure refrigerant flowing out of the indoor heat exchanger 81 is decompressed by the indoor expansion valve 82 and becomes a refrigerant of intermediate pressure. Here, the refrigerant subcooling degree in the indoor heat exchanger 81 as a condenser is calculated based on the refrigerant temperature detected by the refrigerant temperature sensor 84 and the high-pressure saturation temperature obtained from the outdoor unit 2a and the outdoor unit 2b, and the opening degree of the indoor expansion valve 82 of the indoor unit 8c is determined based on the refrigerant subcooling degree.

[0098] Then, the intermediate-pressure refrigerant flowing out of the indoor unit 8c and flowing out to the liquid pipe 32 flows into the outdoor unit 2a and the outdoor unit 2b through the branch pipe 72 and the liquid branch pipes 32a and 32b. The intermediate-pressure refrigerant flowing into the outdoor unit 2a and the outdoor unit 2b is decompressed when passing through the first outdoor expansion valve 40 and the second outdoor expansion valve 41 set to the opening corresponding to the superheat degree of the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25, and becomes a low-pressure refrigerant, and flows into the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25. The low-pressure refrigerant flowing into the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 exchanges heat with the outdoor air and evaporates. Then, the low-pressure refrigerant flowing out of the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 passes through the first three-way valve 22 and the second three-way valve 23, and is sucked into the compressor 21 through the accumulator 27 and compressed again.

[0099] [Air conditioning device with cooling and heating switching method] Next, refer to Figure 2 , the structure and operation example of the air conditioning device 20 of the cooling and heating switching method are described.

[0100] like Figure 2As shown, the air conditioner 20 of the cold-heat switching mode is different from the air conditioner of the above-mentioned cold-heat free mode, and does not include the branching units 6a to 6c, the low-pressure gas pipe 31, the low-pressure gas branch pipe 31a, the low-pressure gas branch pipe 31b, and the branch pipe 71. That is, in the air conditioner 20 of the cold-heat switching mode, the stop valve 45 of each outdoor unit 2a and the outdoor unit 2b is closed, and each outdoor unit 2a and the outdoor unit 2b are connected in parallel with each indoor unit 8a to 8c through two connecting pipes, namely, the gas pipe 30 (equivalent to the high-pressure gas pipe 30 in the air conditioner 10 of the cold-heat free mode) and the liquid pipe 32. The outdoor unit 2a, the outdoor unit 2b, and the indoor unit 8a to 8c in the air conditioner 20 of the cold-heat switching mode have the same structure as the outdoor unit 2a, the outdoor unit 2b, and the indoor unit 8a to 8c of the air conditioner 10 of the cold-heat free mode, so their description is omitted.

[0101] In the air conditioning device 20 of the cooling and heating switching mode, during the heating operation, similarly to the full heating operation of the air conditioning device 10 of the cooling and heating free mode, the first three-way valve 22 of each outdoor unit 2a and the outdoor unit 2b is switched so that the port b is connected to the port c (at Figure 2 ), and the second three-way valve 23 is switched so that port e is connected to port f (indicated by a solid line in FIG. Figure 2 Then, the four-way valve 29 of each outdoor unit 2a and outdoor unit 2b is switched so that port g is connected to port h and port k is connected to port m (in Figure 2 Indicated by solid lines in FIG. 1 ). Thus, the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 of each outdoor unit 2a or 2b can function as an evaporator, and the indoor unit 81 of each indoor unit 8a to 8c can function as a condenser.

[0102] On the other hand, in the air conditioning device 20 of the cooling and heating switching mode, in the cooling operation, similarly to the full cooling operation of the air conditioning device 10 of the cooling and heating free mode, the first three-way valve 22 of each outdoor unit 2a and the outdoor unit 2b is switched so that the port a and the port b are connected (at Figure 2 ), and the second three-way valve 23 is switched so that port d is connected to port e (indicated by a dotted line in FIG. Figure 2 Then, the four-way valve 29 of each outdoor unit 2a and outdoor unit 2b is switched so that port g is connected to port k and port h is connected to port m (in Figure 2 Thus, the first outdoor heat exchanger 24 and the second outdoor heat exchanger 25 of each outdoor unit 2a or 2b can function as a condenser, and the indoor unit 81 of each indoor unit 8a to 8c can function as an evaporator.

[0103] The refrigerant circuit of the air conditioning device 20 is constructed as described above, and the refrigerant is caused to flow in the refrigerant circuit, thereby establishing a refrigeration cycle. Figure 2 As shown in FIG. 1 , the state of the refrigerant circuit in which the indoor units 8a to 8c can simultaneously perform cooling operation or heating operation is also referred to as a "second refrigerant circuit state."

[0104] [Choice of hot and cold switching mode and hot and cold free mode] Here, in an air conditioning device that has a four-way valve 29 and can handle both the hot and cold switching mode and the hot and cold free mode by switching the four-way valve 29, it is necessary to unify all outdoor units in either the hot and cold switching mode or the hot and cold free mode during operation. Generally, for outdoor units that can handle both the hot and cold switching mode and the hot and cold free mode, it is assumed that a switching unit (equivalent to a DIP switch) that switches the refrigerant circuit to either the hot and cold switching mode or the hot and cold free mode is provided in each outdoor unit. Figure 3 The refrigerant circuit selection unit 113a, 113b is provided in the refrigerant circuit selection unit 113a, 113b. When the refrigerant circuit selection unit 113a, 113b is provided, the operator operates the switching unit for each outdoor unit. However, due to operating errors or forgetting to operate the switching unit, the air conditioner may be operated in a state where all outdoor units are not uniformly in the cooling and heating switching mode or the cooling and heating free mode.

[0105] For example, in an air conditioner operating in a cooling and heating free mode, consider a case where the outdoor unit 2a is mistakenly switched to a cooling and heating switching mode. Figure 4 As shown, the four-way valve 29 of the outdoor unit 2a is switched so that the port g is connected to the port k and the port h is connected to the port m (hereinafter also referred to as the disconnected state), and the four-way valve 29 of the outdoor unit 2b is switched so that the port g is connected to the port h and the port k is connected to the port m (hereinafter also referred to as the connected state).

[0106] If the full cooling operation is started in this state, the refrigerant discharged from the compressor 21 of the outdoor unit 2b in the free cooling and heating mode flows into the high-pressure gas branch pipe 30b through the four-way valve 29 of the outdoor unit 2b, and after merging with the refrigerant flowing out of the indoor heat exchanger 81 of each indoor unit 8a to 8c functioning as an evaporator at the branch 70, flows into the outdoor unit 2a in the cooling and heating switching mode through the high-pressure gas branch pipe 30a. That is, the high-temperature and high-pressure refrigerant flowing in from the outdoor unit 2b flows into the outdoor unit low-pressure gas pipe 34 in the outdoor unit 2a and is sucked into the compressor 21 of the outdoor unit 2a. As a result, the low pressure in the outdoor unit 2a in the cooling and heating switching mode rises, and the high pressure also rises with this, and the temperature of the refrigerant discharged from the compressor 21 may exceed the upper limit of the performance usage range.

[0107] In addition, in the air conditioner operating in the cooling and heating switching mode, when the outdoor unit 2b is mistakenly switched to the cooling and heating free mode, Figure 5 In this case, as in the case where the outdoor unit 2a is mistakenly switched to the hot-cold switching mode and performs full cooling operation in the air-conditioning device operating in the hot-cold free mode, the four-way valve 29 of the outdoor unit 2a is set to the disconnected state, and the four-way valve 29 of the outdoor unit 2b is set to the connected state, and the high-temperature and high-pressure refrigerant flowing in from the outdoor unit 2b flows into the outdoor unit low-pressure gas pipe 34 in the outdoor unit 2a and is sucked into the compressor 21 of the outdoor unit 2a. Therefore, the low pressure in the outdoor unit 2a in the hot-cold switching mode rises, and the high pressure also rises accordingly, and the temperature of the refrigerant discharged from the compressor 21 may exceed the upper limit of the performance usage range.

[0108] Even in the same operation mode in the outdoor unit of the free cooling and heating mode and the outdoor unit of the hot and cold switching mode, such a problem occurs when the connections between the ports of the four-way valve 29 are different. As described above, even in the same cooling operation, the four-way valve 29 is in the on state in the free cooling and heating mode, and the four-way valve 29 is in the off state in the hot and cold switching mode, so the following problem occurs: the high-temperature and high-pressure refrigerant flowing out of the outdoor unit of the free cooling and heating mode flows into the low-pressure side of the outdoor unit of the free cooling and heating mode and the outdoor unit of the hot and cold switching mode as described above.

[0109] In order to solve the above problems, the air conditioning apparatus of the present embodiment transmits a state signal including information related to the selected refrigerant circuit state from one of the plurality of outdoor units to the other outdoor units when either the cold and hot free mode (first refrigerant circuit state) or the cold and hot switching mode (second refrigerant circuit state) is selected in the outdoor unit among the plurality of outdoor units. The other outdoor units that receive the state signal select the same refrigerant circuit state as the refrigerant circuit state selected by the one outdoor unit, regardless of the refrigerant circuit state selected by the refrigerant circuit selection unit.

[0110] Thus, all outdoor units can be reliably unified into the cooling and heating switch mode or the cooling and heating free mode, thereby preventing problems caused by the mixed existence of outdoor units of the cooling and heating free mode and outdoor units of the cooling and heating switch mode.

[0111] [Details of this embodiment] The following describes the details of this embodiment. In this embodiment, one of the two outdoor units 2a and 2b is set as a main outdoor unit, and the other outdoor unit is set as a sub-outdoor unit that operates according to the instructions of the main outdoor unit. In the following description, the outdoor unit 2a is also referred to as the main outdoor unit 2a, and the outdoor unit 2b is also referred to as the sub-outdoor unit 2b.

[0112] (Basic Action) Figure 6 This is a flowchart showing an example of a control procedure of each outdoor unit 2a, 2b related to setting of the refrigerant circuit state of the present invention from the time the air conditioner 10 is powered on to the start of operation after the air conditioner 10 is installed.

[0113] When power is supplied to the main outdoor unit 2a and the sub-outdoor unit 2b, the control device 110a of the main outdoor unit 2a determines the refrigerant circuit state of the main outdoor unit 2a (steps 101 and 102). The determination of the refrigerant circuit state of the main outdoor unit 2a is performed by the CPU 111a based on which of the first refrigerant circuit state and the second refrigerant circuit state is selected in the refrigerant circuit selection unit 113a of the control device 110a. The CPU 111a stores the determination result of the refrigerant circuit state in the storage unit 112a.

[0114] It should be noted that after the outdoor units 2a and 2b are connected to the indoor units 8a to 8c via the connecting pipes, power is supplied to the main outdoor unit 2a and the sub-outdoor unit 2b. Figure 1 In the case of the cooling and heating free air conditioning device 10 shown in FIG. 1 , it is necessary to make each outdoor unit 2a and the outdoor unit 2b both in the first refrigerant circuit state. Figure 2 In the case of the cooling / heating switching type air conditioner 20 shown, it is necessary to place both the outdoor unit 2a and the outdoor unit 2b in the second refrigerant circuit state.

[0115] Next, the CPU 111a of the control device 110a generates a status signal including information related to the refrigerant circuit state selected by the main outdoor unit 2a, and transmits the generated status signal from the communication unit 114a to the communication unit 114b of the sub-outdoor unit 2b (step 103). Specifically, when the first refrigerant circuit state is selected in the main outdoor unit 2a, the status signal related to the first refrigerant circuit state is transmitted, and when the second refrigerant circuit state is selected in the main outdoor unit 2a, the status signal related to the second refrigerant circuit state is transmitted.

[0116] Next, the control device 110b of the sub-outdoor unit 2b receives the state signal through the communication unit 114b, and sets the sub-outdoor unit 2b to the same refrigerant circuit state as the refrigerant circuit state selected by the main outdoor unit 2a based on the received state signal (step 104). Specifically, when the sub-outdoor unit 2b receives the state signal related to the first refrigerant circuit state, the CPU 111b of the sub-outdoor unit 2b sets the sub-outdoor unit 2b to the first refrigerant circuit state, and when the sub-outdoor unit 2b receives the state signal related to the second refrigerant circuit state, the CPU 111b sets the sub-outdoor unit 2b to the second refrigerant circuit state. The CPU 111b may also store the received state signal in the storage unit 112b.

[0117] As described above, by selecting the refrigerant circuit state included in the state signal sent from the main outdoor unit 2a, the CPU 111b switches the refrigerant circuit state of the sub-outdoor unit 2b to the same refrigerant circuit state as the main outdoor unit 2a, even if the refrigerant circuit state of the sub-outdoor unit 2b is erroneously different from the refrigerant circuit state of the main outdoor unit 2a due to the operation of the refrigerant circuit selector 113b. Thus, even if the refrigerant circuit state of the sub-outdoor unit 2b is erroneously selected, the main outdoor unit 2a and the sub-outdoor unit 2b can be set to the same refrigerant circuit state.

[0118] After the setting of the refrigerant circuit state of the sub-outdoor unit 2b is completed, the main outdoor unit 2a and the sub-outdoor unit 2b are started (step 105). The operation control command for the sub-outdoor unit 2b (operation mode such as cooling / heating, the rotation speed of the compressor 21 corresponding to the air conditioning capacity required by the indoor units 8a to 8c, etc.) is sent from the main outdoor unit 2a to the sub-outdoor unit 2b. The communication unit 114a of the main outdoor unit 2a and the communication unit 114b of the sub-outdoor unit 2b communicate at a given cycle, thereby the main outdoor unit 2a can grasp whether the power supply to the sub-outdoor unit 2b is cut off, and can also regularly obtain the operation state of the sub-outdoor unit 2b (the rotation speed of the compressor 21, the rotation speed of the outdoor fan 26, etc.). At this time, the detection values ​​of various sensors of the sub-outdoor unit 2b can also be sent to the main outdoor unit 2a. As a result, the main outdoor unit 2a can grasp the operation state of the sub-outdoor unit 2b.

[0119] (Operation restart based on power restoration) Next, the operation restarting operation of the main outdoor unit 2a and the sub-outdoor unit 2b after the power outage is restored will be described.

[0120] Figure 7It is a flowchart showing an example of control steps for each outdoor unit 2a and outdoor unit 2b related to the setting of the refrigerant circuit state of the present invention, from the time when the power supply to the main outdoor unit 2a and the sub-outdoor unit 2b is cut off and then the power supply to them is restarted to the start of operation.

[0121] If power is supplied to the main outdoor unit 2a again after power failure recovery, the control device 110a of the main outdoor unit 2a confirms the refrigerant circuit state of the main outdoor unit 2a (steps 201 and 202). As described above, the CPU 111a determines the refrigerant circuit state of the main outdoor unit 2a based on which of the first refrigerant circuit state and the second refrigerant circuit state is selected by the refrigerant circuit selection unit 113a in the control device 110a. The CPU 111a stores the determination result of the refrigerant circuit state in the storage unit 112a.

[0122] Next, the CPU 111a of the control device 110a generates a state signal including information on the confirmed refrigerant circuit state of the main outdoor unit 2a, and transmits the generated state signal from the communication unit 114a to the communication unit 114b of the sub-outdoor unit 2b (step 203).

[0123] Next, the control device 110b of the sub-outdoor unit 2b sets the sub-outdoor unit 2b to the same refrigerant circuit state as the refrigerant circuit state selected by the main outdoor unit 2a based on the state signal received through the communication unit 114b (step 204). After the setting of the refrigerant circuit state of the sub-outdoor unit 2b is completed, the main outdoor unit 2a and the sub-outdoor unit 2b are started again (step 205).

[0124] According to the present embodiment, even when the power supply to the main outdoor unit 2b and the sub-outdoor unit 2b is cut off, when the power supply is restored thereafter, the refrigerant circuit state of the sub-outdoor unit 2b can be set based on the state signal generated corresponding to the refrigerant circuit state set by the refrigerant circuit selection unit 113a of the main outdoor unit 2a, and the operation can be restarted. Thus, even when the refrigerant circuit state of the sub-outdoor unit 2b is reset due to power cutoff, the refrigerant circuit state of the sub-outdoor unit 2b can be automatically set to the refrigerant circuit state of the main outdoor unit 2a before the reset along with the restart of power supply. Therefore, it is not necessary for the operator to perform the refrigerant circuit state reset operation on the main outdoor unit 2a. It should be noted that, when only the power supply to the main outdoor unit 2a is cut off, the refrigerant circuit state of the sub-outdoor unit 2b can be reset by the same steps as above.

[0125] Figure 8It is a flowchart showing an example of control steps of each outdoor unit 2a and outdoor unit 2b related to the setting of the refrigerant circuit state of the present invention, from the time when the power supply to the sub-outdoor unit 2b is cut off and then the power supply to the sub-main outdoor unit 2b is restarted to the start of operation.

[0126] As described above, since the communication unit 114a of the main outdoor unit 2a and the communication unit 114b of the sub-outdoor unit 2b communicate regularly, the main outdoor unit 2a can grasp whether the power supply to the sub-outdoor unit 2b is cut off by whether the regular communication is performed. If the power supply to the sub-outdoor unit 2b is detected to be restarted by restarting the communication with the interrupted sub-outdoor unit 2b, the control device 110a of the main outdoor unit 2a generates a state signal including the refrigerant circuit state of the main outdoor unit 2a and transmits it to the sub-outdoor unit 2b (steps 301 and 302).

[0127] At this time, the control device 110a can be set to re-determine the refrigerant circuit state of the main outdoor unit 2a based on the refrigerant circuit selection unit 113a, or the refrigerant circuit state determined at the start of operation of the main outdoor unit 2a can be stored in the storage unit 112a and read out the refrigerant circuit state from the storage unit 112a.

[0128] Next, the control device 110b of the sub-outdoor unit 2b sets the sub-outdoor unit 2b to the same refrigerant circuit state as the refrigerant circuit state selected by the main outdoor unit 2a based on the state signal received by the communication unit 114b (step 303). After the setting of the refrigerant circuit state of the sub-outdoor unit 2b is completed, the sub-outdoor unit 2b is started again (step 304).

[0129] According to the present embodiment, when the power supply to the sub-outdoor unit 2b is cut off and then the power supply is restored, the refrigerant circuit state of the sub-outdoor unit 2b can be set based on the state signal including the refrigerant circuit state of the main outdoor unit 2a and the operation can be restarted. Thus, even if the refrigerant circuit state of the sub-outdoor unit 2b is reset due to power cutoff, when the power supply to the sub-outdoor unit 2a is restarted, the refrigerant circuit state of the sub-outdoor unit 2b can be automatically set to the refrigerant circuit state of the main outdoor unit 2a before the reset.

[0130] As described above, according to the present embodiment, in an air conditioner having a plurality of outdoor units 2a and 2b capable of selecting a cold-heat switching mode and a cold-heat free mode, all outdoor units 2a and 2b can be reliably unified into the cold-heat switching mode or the cold-heat free mode. Therefore, it is possible to reliably prevent the occurrence of an adverse condition of the air conditioner caused by a mixture of outdoor units in the cold-heat free mode and outdoor units in the cold-heat switching mode.

[0131] In addition, according to the present embodiment, even when the power supply to the main outdoor unit 2a and the sub-outdoor unit 2b is cut off due to a power outage or the like, the refrigerant circuit state of the sub-outdoor unit 2a can be automatically restored to the refrigerant circuit state before the power outage when the power supply is restored. Therefore, the operation of the main outdoor unit 2a and the sub-outdoor unit 2b can be restarted without the operator having to perform a refrigerant circuit state reset operation.

[0132] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, It is a matter of course that various changes can be added.

[0133] For example, in the above embodiment, the air conditioner 10 and the air conditioner 20 having two outdoor units 2a and 2b and three indoor units 8a to 8c are described as an example, but the number of outdoor units and indoor units is not limited to this example, and the number of outdoor units may be more than three, and the number of indoor units may be two or more than four. It should be noted that when there are more than three outdoor units, any one outdoor unit may be used as the main outdoor unit, and the refrigerant circuit state of the remaining outdoor units may be made consistent with the refrigerant circuit state of the main outdoor unit.

[0134] In addition, in the above embodiment, an example of using three connecting pipes (high-pressure gas pipe 30, low-pressure gas pipe 31, liquid pipe 32) as an air-conditioning device 10 of a free-heat-cooling mode is described, but it is not limited to this. Two connecting pipes can also be used to form an air-conditioning device of a free-heat-cooling mode.

[0135] Furthermore, in the above embodiment, a three-way valve (first three-way valve 22, second three-way valve 23) is used as the first flow path switching unit, but it is not limited thereto, and other switching valves such as a four-way valve may also be used. Similarly, as the second flow path switching unit, a four-way valve 29 is used, but it is not limited thereto, and for example, Fig. 9 As shown, two electromagnetic on-off valves are used.

[0136] Fig. 9 This is a refrigerant circuit diagram of an outdoor unit 2a and an outdoor unit 2b that use two electromagnetic opening and closing valves (a first electromagnetic opening and closing valve 29a and a second electromagnetic opening and closing valve 29b) as a second flow path switching unit. Both the first electromagnetic opening and closing valve 29 and the second electromagnetic opening and closing valve are switching valves that only open and close. The first electromagnetic opening and closing valve 29a is provided on the outdoor unit high-pressure gas pipe 33, and switches the connection / disconnection between the discharge side of the compressor 21 and the stop valve 44 according to the instructions of the control devices 110a and 110b. The second electromagnetic opening and closing valve 29b is provided on the refrigerant distribution pipe 37 connecting the outdoor unit high-pressure gas pipe 33 and the outdoor unit low-pressure gas pipe 34, and switches the connection / disconnection between the outdoor unit high-pressure gas pipe 33 and the outdoor unit low-pressure gas pipe 34 according to the instructions of the control devices 110a and 110b.

[0137] When the outdoor unit 2a and the outdoor unit 2b are outdoor units in the free-heating mode (the first refrigerant circuit state), the first electromagnetic on-off valve 29a is set to the on state in all cases of full heating operation, full cooling operation, heating main operation, and cooling main operation, and the second electromagnetic on-off valve 29b is set to the off state in all the above cases. In addition, when the outdoor unit 2a and the outdoor unit 2b are outdoor units in the hot-cold switching mode (the second refrigerant circuit state), the first electromagnetic on-off valve is set to the off state and the second electromagnetic on-off valve is set to the on state in the cooling operation, and the first electromagnetic on-off valve is set to the on state and the second electromagnetic on-off valve 29b is set to the off state in the heating operation.

[0138] Description of Reference Numerals 2a Outdoor unit (main outdoor unit) 2b Outdoor unit (sub-outdoor unit) 6a, 6b, 6c Divider Unit 8a, 8b, 8c Indoor units 10. Air conditioning device with free heating and cooling mode 20 Air conditioning device with hot and cold switching mode 21 Compressor 22 First three-way valve (first flow path switching unit) 23 Second three-way valve (first flow path switching unit) 24 First outdoor heat exchanger 25 Second outdoor heat exchanger 29 Four-way valve (second flow path switching unit) 30 High pressure gas pipe (gas pipe) 31 Low pressure gas pipe 32 Liquid pipe 81 Indoor heat exchanger 110a, 110b Control device 111a, 111b CPU 112a, 112b storage unit 113a, 113b Refrigerant circuit selection unit 114a, 114b communication unit.

Claims

1. An air conditioning device, comprising: a plurality of outdoor units; a plurality of indoor units; and a plurality of connecting pipes, which connect each indoor unit to the plurality of outdoor units in parallel, wherein the air conditioning device can select any one of a first refrigerant circuit state and a second refrigerant circuit state, in which each indoor unit can independently perform cooling operation and heating operation, and in which each indoor unit can simultaneously perform cooling operation or heating operation in the second refrigerant circuit state, The plurality of outdoor units each include a communication unit for communicating between the outdoor units, and a refrigerant circuit selection unit for selecting one of the first refrigerant circuit state and the second refrigerant circuit state. When either the first refrigerant circuit state or the second refrigerant circuit state is selected in one of the plurality of outdoor units, a state signal including information related to the selected refrigerant circuit state is transmitted from a communication unit of the one outdoor unit to communication units of other outdoor units, The other outdoor unit that has received the state signal selects the same refrigerant circuit state as the refrigerant circuit state selected by the one outdoor unit.

2. The air conditioning device according to claim 1, wherein: The refrigerant circuit selector is a switching operation unit that selects one of the first refrigerant circuit state and the second refrigerant circuit state, and the state signal includes information on the refrigerant circuit state selected by the switching operation unit.

3. The air conditioning device according to claim 1 or 2, wherein: Among the plurality of outdoor units, the one outdoor unit is set as a main outdoor unit, and the other outdoor units are set as sub-outdoor units that operate according to instructions of the main outdoor unit. The sub-outdoor unit selects the same refrigerant circuit state as the refrigerant circuit state selected by the main outdoor unit based on the state signal transmitted from the main outdoor unit.

4. The air conditioning device according to claim 2, wherein: Among the plurality of outdoor units, the one outdoor unit is set as a main outdoor unit, and the other outdoor units are set as sub-outdoor units that operate according to instructions of the main outdoor unit. The sub-outdoor unit selects the refrigerant circuit state included in the state signal transmitted from the main outdoor unit when the refrigerant circuit state selected by the switching operation unit of the sub-outdoor unit is different from the refrigerant circuit state included in the state signal transmitted from the main outdoor unit.

5. The air conditioning device according to claim 4, wherein: When power supply to the plurality of outdoor units is started or resumed, the main outdoor unit confirms the refrigerant circuit state selected by the switching operation unit of the main outdoor unit, and transmits the confirmed refrigerant circuit state to the sub-outdoor unit by including it in the state signal.

6. The air conditioning device according to claim 3, wherein: When starting or restarting the supply of electric power to the sub-outdoor unit, the main outdoor unit includes the refrigerant circuit state selected by the main outdoor unit in the state signal and transmits it to the sub-outdoor unit.

7. The air conditioning device according to claim 1 or 2, wherein: The plurality of outdoor units respectively include a compressor, an outdoor heat exchanger, a first flow path switching unit, and a second flow path switching unit, wherein a refrigerant inlet and outlet of the outdoor heat exchanger is selectively connected to a refrigerant suction pipe or a refrigerant discharge pipe of the compressor via the first flow path switching unit. In the first refrigerant circuit state, three connecting pipes, namely, a first gas pipe and a second gas pipe selectively connected to the refrigerant suction pipe or the refrigerant discharge pipe respectively via the second flow path switching unit, and a liquid pipe connected to another refrigerant inlet and outlet of the outdoor heat exchanger, are used as the plurality of connecting pipes. In the second refrigerant circuit state, two connecting pipes, namely the first gas pipe and the liquid pipe, are used as the plurality of connecting pipes.

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