Outdoor unit, indoor unit, and air conditioning system

Abstract

To enable use of a common indoor unit regardless of specifications of an air conditioning system.SOLUTION: An air conditioning system 10 includes: a refrigerant circuit RC 1; an outdoor unit 40; and a plurality of indoor units 30 connected in parallel with the outdoor unit 40. The outdoor unit 40 includes: an outdoor expansion valve 84, etc. for regulating pressure of a refrigerant to be supplied to the indoor units 30; and an outdoor control section 61 controlling the outdoor expansion valve 84, etc. When a valve unit 50 provided between the indoor units 30 and the outdoor unit 40 and switching a flow of the refrigerant to the indoor units 30 is not included in the air conditioning system 10, the air conditioning system is operated in a first control mode M1 of regulating the pressure of the refrigerant to be supplied to the indoor units 30 by controlling the outdoor expansion valve 84, etc. When the valve unit 50 is included in the air conditioning system 10, the air conditioning system is operated in a second control mode M2 of regulating the pressure of the refrigerant to be supplied to the indoor units 30 by controlling a first motor-operated valve 52, etc. included in the valve unit 50.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to an outdoor unit, an indoor unit, and an air conditioning system. [Background technology]

[0002] Patent Document 1 discloses an air conditioning system equipped with an outdoor unit (heat source unit), an indoor unit (utilization unit), and a valve unit (refrigerant flow path switching unit). In the air conditioning system, a control valve is provided in each of the outdoor unit, indoor unit, and valve unit. Patent Document 1 further discloses an air conditioning system configured to omit the control valve in the indoor unit and control the refrigerant supplied to the indoor unit with a control valve in the outdoor unit or the valve unit (see paragraph 0190). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 064566 Summary of the Invention [Problem to be solved by the invention]

[0004] The specifications of the air conditioning system include a first specification (so-called cooling / heating switchable specification) in which all of the multiple indoor units are switched to either cooling operation or heating operation, and a second specification (so-called cooling / heating free specification) in which the multiple indoor units can be individually selected to operate in either cooling operation or heating operation, and the specifications of the outdoor unit, the presence or absence of a valve unit, and the presence or absence of a control valve in the outdoor unit vary depending on the specification.In other words, the product lineup of the air conditioning system must include at least two models of indoor units, one with a control valve and the other with a control valve, which increases the manufacturing and management costs of the air conditioning system.

[0005] An object of the present disclosure is to enable the use of a common indoor unit regardless of the specifications of the air conditioning system. [Means for solving the problem]

[0006] (1) The outdoor unit of the present disclosure is provided in an air conditioning system including a refrigerant circuit that performs a refrigeration cycle and a plurality of indoor units, and is an outdoor unit to which the plurality of indoor units are connected in parallel, and the outdoor unit is provided with a first control valve that adjusts the pressure of the refrigerant supplied to the indoor units, and a control unit that controls the first control valve, and when the air conditioning system does not include a valve unit that is provided between the indoor unit and the outdoor unit and switches the flow of refrigerant to the indoor units, the control unit operates the air conditioning system in a first control mode that controls the first control valve to adjust the pressure of the refrigerant supplied to the indoor units, and when the valve unit is included in the air conditioning system, the control unit operates the air conditioning system in a second control mode that controls a second control valve included in the valve unit to adjust the pressure of the refrigerant supplied to the indoor units.

[0007] In the case where the air conditioning system is of a first specification in which all of the multiple indoor units can be switched to either cooling operation or heating operation, the control unit controls the first control valve of the outdoor unit, and in the case where the air conditioning system is of a second specification in which the multiple indoor units can be operated by individually selecting cooling operation or heating operation for each indoor unit, the control unit controls the second control valve of the valve unit, and so on. This makes it possible to switch the valves controlled by the control unit and the control content according to the specifications of the air conditioning system. This eliminates the need to provide control valves in the indoor units even when the air conditioning system is of the second specification, and makes it possible to use common indoor units that do not have control valves, regardless of the specifications of the air conditioning system.

[0008] (2) The indoor unit of the present disclosure is provided in an air conditioning system including a refrigerant circuit that performs a refrigeration cycle and an outdoor unit, and is a plurality of indoor units connected in parallel to the outdoor unit, wherein the outdoor unit is provided with a first control valve that adjusts the pressure of the refrigerant supplied to the indoor unit, and the indoor unit is provided with a control unit that controls the first control valve, and when the air conditioning system does not include a valve unit that is provided between the indoor unit and the outdoor unit and switches the flow of refrigerant to the indoor unit, the control unit operates the air conditioning system in a first control mode that controls the first control valve to adjust the pressure of the refrigerant supplied to the indoor unit, and when the valve unit is included in the air conditioning system, the control unit operates the air conditioning system in a second control mode that controls a second control valve included in the valve unit to adjust the pressure of the refrigerant supplied to the indoor unit.

[0009] The valve to be controlled and the control content can be switched according to the specifications of the air conditioning system, such as controlling the first control valve of the outdoor unit when the air conditioning system is of the first specification, in which multiple indoor units can all be switched to either cooling operation or heating operation, and controlling the second control valve of the valve unit when the air conditioning system is of the second specification, in which multiple indoor units can be individually selected to operate in cooling operation or heating operation for each indoor unit.This makes it unnecessary to provide control valves in the indoor units even when the air conditioning system is of the second specification, and makes it possible to use common indoor units that do not have control valves, regardless of the specifications of the air conditioning system.

[0010] (3) The air conditioning system of the present disclosure is an air conditioning system including a refrigerant circuit that performs a refrigeration cycle, an outdoor unit, and a plurality of indoor units connected in parallel to the outdoor unit, wherein the air conditioning system is equipped with a control unit that controls the operation of the air conditioning system, the outdoor unit is equipped with a first control valve that adjusts the pressure of the refrigerant supplied to the indoor unit, and when the air conditioning system does not include a valve unit that is provided between the indoor unit and the outdoor unit and switches the flow of refrigerant to the indoor unit, it operates in a first control mode that controls the first control valve to adjust the pressure of the refrigerant supplied to the indoor unit, and when the valve unit is included in the air conditioning system, it operates in a second control mode that controls a second control valve included in the valve unit to adjust the pressure of the refrigerant supplied to the indoor unit.

[0011] The valve to be controlled and the control content can be switched according to the specifications of the air conditioning system, such as controlling the first control valve of the outdoor unit when the air conditioning system is of the first specification, in which multiple indoor units can all be switched to either cooling operation or heating operation, and controlling the second control valve of the valve unit when the air conditioning system is of the second specification, in which multiple indoor units can be individually selected to operate in cooling operation or heating operation for each indoor unit.This makes it unnecessary to provide control valves in the indoor units even when the air conditioning system is of the second specification, and makes it possible to use common indoor units that do not have control valves, regardless of the specifications of the air conditioning system.

[0012] (4) In the air conditioning system of the present disclosure, it is preferable that the control unit automatically selects the second control mode when the valve unit is included in the air conditioning system.

[0013] In this case, simply by connecting the valve unit to the indoor unit and the outdoor unit, it is possible to automatically select the second control mode that is suited to the specifications of the air conditioning system.

[0014] (5) Preferably, the air conditioning system of the present disclosure further includes a selection means for manually selecting the first control mode and the second control mode.

[0015] In this case, the user can manually select the first control mode or the second control mode.

[0016] (6) In the air conditioning system of the present disclosure, when the valve unit is not included in the air conditioning system, the control unit controls the first control valve in the first control mode, When the valve unit is included in the air conditioning system, it is preferable that the control unit controls the second control valve in the second control mode.

[0017] In this case, the first control mode or the second control mode can be automatically selected by the control unit.

[0018] (7) In the air conditioning system of the present disclosure, in the air conditioning system including the valve unit, it is preferable that, in the event of a refrigerant leak in the indoor unit, the second control valve cuts off the supply of refrigerant to the indoor unit.

[0019] In this case, if the air conditioning system is of the second specification, the second control valve of the valve unit can be used as a control valve to adjust the pressure of the refrigerant and also as a shutoff valve to shut off the refrigerant. In such an air conditioning system, there is no need to provide a separate shutoff valve, which reduces manufacturing costs.

[0020] (8) In the air conditioning system of the present disclosure, it is preferable that the control unit further includes an indoor control unit that controls the operation of the indoor unit, the indoor unit has the indoor control unit, and when the indoor unit and the outdoor unit are connected, information about the outdoor unit is written to the indoor control unit, and the indoor control unit controls the indoor unit based on the information about the outdoor unit.

[0021] In this case, simply by connecting the indoor unit and the outdoor unit, the control contents of the indoor unit can be automatically switched to contents that correspond to the specifications of the outdoor unit. [Brief explanation of the drawings]

[0022] [Figure 1A] 1 is a schematic configuration diagram of an air conditioning system according to a first embodiment of the present disclosure. [Figure 1B] FIG. 5 is a schematic configuration diagram of an air conditioning system according to a second embodiment of the present disclosure. [Figure 2A] FIG. 10 is a schematic configuration diagram of an air conditioning system according to a third embodiment of the present disclosure. [Figure 2B] FIG. 10 is a schematic configuration diagram of an air conditioning system according to a fourth embodiment of the present disclosure. [Figure 3] 1 is a refrigerant circuit diagram of an air conditioning system according to a first embodiment of the present disclosure. [Figure 4] 1 is a block diagram of an air conditioning system according to a first embodiment of the present disclosure. [Figure 5] FIG. 4 is a refrigerant circuit diagram of an air conditioning system according to a second embodiment of the present disclosure. [Figure 6] FIG. 4 is a block diagram of an air conditioning system according to a second embodiment of the present disclosure. [Figure 7] FIG. 4 is a refrigerant circuit diagram of an air conditioning system according to a third embodiment of the present disclosure. [Figure 8] FIG. 10 is a block diagram of an air conditioning system according to a third embodiment of the present disclosure. [Figure 9] FIG. 10 is a refrigerant circuit diagram of an air conditioning system according to a fourth embodiment of the present disclosure. [Figure 10] FIG. 10 is a block diagram of an air conditioning system according to a fourth embodiment of the present disclosure. [Figure 11] FIG. 3 is a control flow diagram of a control unit in the air conditioning system of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0023] (Air conditioning system overview) FIG. 1A is a schematic configuration diagram of an air conditioning system according to a first embodiment of the present disclosure. FIG. 1B is a schematic configuration diagram of an air conditioning system according to a second embodiment of the present disclosure. FIG. 2A is a schematic configuration diagram of an air conditioning system according to a third embodiment of the present disclosure. FIG. 2B is a schematic configuration diagram of an air conditioning system according to a fourth embodiment of the present disclosure. FIGS. 1A, 1B, 2A, and 2B show a schematic configuration of an air conditioning system 10 according to the present disclosure. In the following description, the air conditioning system 10 according to the first embodiment (see FIG. 1A) will be referred to as a first air conditioning system 11, the air conditioning system 10 according to the second embodiment (see FIG. 1B) will be referred to as a second air conditioning system 12, the air conditioning system 10 according to the third embodiment (see FIG. 2A) will be referred to as a third air conditioning system 13, and the air conditioning system 10 according to the fourth embodiment (see FIG. 2B) will be referred to as a fourth air conditioning system 14. In the following explanation, when simply referring to "air conditioning system 10," the explanation is of a configuration common to each of the first to fourth air conditioning systems 11 to 14. Note that in the following explanation, the "first specification" refers to a specification in which, in an air conditioner having multiple indoor units, all of the indoor units are switched to either cooling operation or heating operation (so-called cooling / heating switching specification), and the "second specification" refers to a specification in which, in an air conditioner having multiple indoor units, each indoor unit can be individually selected to operate in cooling operation or heating operation (so-called cooling / heating free specification).

[0024] 1A, 1B, 2A, and 2B is installed in a building, a factory, etc., and provides air conditioning for the space to be air-conditioned. The air conditioning system 10 is equipped with an air conditioner 20 including an indoor unit 30 and an outdoor unit 40. The air conditioner 20 cools and heats the space to be air-conditioned by operating a vapor compression refrigeration cycle.

[0025] The air conditioning system 10 shown in Figures 1A and 1B is equipped with a first specification air conditioner 20. Specifically, the first air conditioning system 11 shown in Figure 1A is equipped with a first specification first air conditioner 21, and the second air conditioning system 12 shown in Figure 1B is equipped with a first specification second air conditioner 22. In the following explanation, the outdoor unit 40 of the first air conditioner 21 and the second air conditioner 22 will be referred to as the first outdoor unit 41. In other words, the first air conditioner 21 and the second air conditioner 22 are equipped with a common first outdoor unit 41. In the following explanation, when simply referring to an "air conditioner 20," a description is given of the configuration common to the first to fourth air conditioners 21 to 24.

[0026] The air conditioning system 10 shown in Figures 2A and 2B is equipped with a second specification air conditioner 20. Specifically, the third air conditioning system 13 shown in Figure 2A is equipped with a second specification third air conditioner 23, and the fourth air conditioning system 14 shown in Figure 2B is equipped with a second specification fourth air conditioner 24. In the following explanation, the outdoor units 40 of the third air conditioner 23 and the fourth air conditioner 24 will be referred to as second outdoor units 42. In other words, the third air conditioner 23 and the fourth air conditioner 24 are equipped with a common second outdoor unit 42.

[0027] As shown in FIGS. 1A, 1B, 2A and 2B, the first to fourth air conditioners 21 to 24 each include a common indoor unit 30.

[0028] The air conditioner 20 is equipped with refrigerant piping 25. The refrigerant piping 25 of the first air conditioner 21 and the second air conditioner 22 includes a liquid pipe 25L and a gas pipe 25G. The refrigerant piping 25 of the third air conditioner 23 and the fourth air conditioner 24 includes a liquid pipe 25L, a high- and low-pressure gas pipe 25G1, and an intake gas pipe 25G2.

[0029] 1B, 2A, and 2B, the second air conditioner 22, the third air conditioner 23, and the fourth air conditioner 24 further include a valve unit 50. The valve unit 50 included in the second air conditioner 22 is a shutoff valve unit 51 provided between the indoor unit 30 and the first outdoor unit 41. The valve unit 50 included in the third air conditioner 23 is a refrigerant flow path switching unit 55 provided between the indoor unit 30 and the second outdoor unit 42. The valve unit 50 included in the fourth air conditioner 24 is a shutoff valve unit 51 and a refrigerant flow path switching unit 55 provided between the indoor unit 30 and the second outdoor unit 42.

[0030] (Regarding the first air conditioning system) FIG. 3 is a refrigerant circuit diagram of the air conditioning system according to the first embodiment of the present disclosure. FIG. 4 is a block diagram of the air conditioning system according to the first embodiment of the present disclosure. As shown in FIGS. 1A, 3, and 4, the first air conditioning system 11 includes a first air conditioner 21. The first air conditioner 21 is a multi-type air conditioner in which a plurality of indoor units 30 are connected in parallel to a first outdoor unit 41. In the example shown in FIG. 3, two or more indoor units 30 are connected to one first outdoor unit 41. However, the number of first outdoor units 41 and indoor units 30 is not limited. The first air conditioner 21 can switch between cooling operation and heating operation to air-condition a target space.

[0031] The first air conditioner 21 has a refrigerant circuit RC1. The refrigerant circuit RC1 circulates refrigerant between the first outdoor unit 41 and the indoor unit 30. The refrigerant circuit RC1 includes a compressor 81, a four-way switching valve 82, an outdoor heat exchanger 83, an outdoor expansion valve 84, a liquid shut-off valve 85, an indoor heat exchanger 31, a gas shut-off valve 86, and refrigerant piping 25 (liquid pipe 25L and gas pipe 25G) that connects these components.

[0032] (About the indoor unit) The indoor unit 30 is equipped with an indoor heat exchanger 31. The indoor heat exchanger 31 constitutes a refrigerant circuit RC1. The indoor heat exchanger 31 is a cross fin tube type or microchannel type heat exchanger, and is used to exchange heat with indoor air.

[0033] The indoor unit 30 is equipped with an indoor fan 32 and an indoor temperature sensor 33. The indoor fan 32 is configured to take in indoor air into the indoor unit 30, perform heat exchange between the taken-in air and the indoor heat exchanger 31, and then blow the air out into the room. The indoor fan 32 is equipped with a motor whose operating rotation speed can be adjusted by inverter control. The indoor temperature sensor 33 detects the temperature inside the room.

[0034] As explained above, the indoor unit 30 of the present disclosure does not have a motor-operated valve (indoor expansion valve) inside the indoor unit 30. In the air conditioning system 10 of the present disclosure, by using an indoor unit 30 that does not have a motor-operated valve (indoor expansion valve) inside, it is possible to use a common indoor unit 30 regardless of the specifications of the outdoor unit 40.

[0035] (Regarding the first outdoor unit) As shown in FIG. 3, the first outdoor unit 41 includes a compressor 81, a four-way switching valve 82, an outdoor heat exchanger 83, an outdoor expansion valve 84, a liquid shut-off valve 85, a gas shut-off valve 86, and the like.

[0036] The compressor 81 draws in a low-pressure gaseous refrigerant and discharges a high-pressure gaseous refrigerant. The compressor 81 is equipped with a motor whose operating rotation speed can be adjusted by inverter control. The compressor 81 is a variable capacity type (variable capacity type) whose capacity (capacity) can be changed by inverter control of the motor. However, the compressor 81 may also be a fixed capacity type.

[0037] The four-way switching valve 82 reverses the flow of refrigerant in the refrigerant piping, switching the refrigerant discharged from the compressor 81 to either the outdoor heat exchanger 83 or the indoor heat exchanger 31. This allows the first air conditioner 21 to switch between cooling operation and heating operation.

[0038] The outdoor heat exchanger 83 is, for example, a cross-fin tube or microchannel type heat exchanger, and is used to exchange heat with a refrigerant using air as a heat source. The outdoor expansion valve 84 is configured as an electric valve that can adjust the flow rate and pressure of the refrigerant. In the first air conditioner 21, the opening degree of the outdoor expansion valve 84 is controlled to adjust the pressure of the refrigerant supplied to the indoor heat exchanger 31.

[0039] The liquid shut-off valve 85 is a manually operated on-off valve. The gas shut-off valve 86 is also a manually operated on-off valve. When closed, the liquid shut-off valve 85 and the gas shut-off valve 86 block the flow of refrigerant in the liquid pipe 25L and the gas pipe 25G, and when open, allow the flow of refrigerant in the liquid pipe 25L and the gas pipe 25G.

[0040] The first outdoor unit 41 further includes an outdoor fan 87. The outdoor fan 87 includes a motor whose operating rotation speed can be adjusted by inverter control. The outdoor fan 87 is configured to take in outdoor air into the first outdoor unit 41, exchange heat between the taken-in air and the outdoor heat exchanger 83, and then blow the air out of the first outdoor unit 41. The first outdoor unit 41 further includes a plurality of refrigerant pressure sensors, a plurality of refrigerant temperature sensors, an outdoor air temperature sensor, etc., which are not shown.

[0041] When the first air conditioner 21 configured as described above performs cooling operation, the four-way selector valve 82 is maintained in the state shown by the solid line in Figure 3. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 81 passes through the four-way selector valve 82 and flows into the outdoor heat exchanger 83, where it exchanges heat with the outdoor air and condenses and liquefies as the outdoor fan 87 operates. The liquefied refrigerant passes through the fully open outdoor expansion valve 84 and flows into each indoor unit 30. In the indoor unit 30, the refrigerant exchanges heat with the indoor air in the indoor heat exchanger 31 and evaporates. The indoor air cooled by the evaporation of the refrigerant is blown into the room by the indoor fan 32, cooling the room. The refrigerant evaporated in the indoor heat exchanger 31 returns to the first outdoor unit 41 through the gas pipe 25G, passes through the four-way selector valve 82 and is drawn into the compressor 81.

[0042] When the first air conditioner 21 performs heating operation, the four-way selector valve 82 is maintained in the state shown by the dashed line in Figure 3. High-temperature, high-pressure gaseous refrigerant discharged from the compressor 81 passes through the four-way selector valve 82 and flows into the indoor heat exchanger 31 of each indoor unit 30. In the indoor heat exchanger 31, the refrigerant exchanges heat with the indoor air and condenses and liquefies. The indoor air heated by the condensation of the refrigerant is blown into the room by the indoor fan 32, heating the room. The refrigerant liquefied in the indoor heat exchanger 31 returns to the first outdoor unit 41 through the liquid pipe 25L, is decompressed to a predetermined low pressure by the outdoor expansion valve 84, and further evaporates by heat exchange with the outdoor air in the outdoor heat exchanger 83. The refrigerant evaporated in the outdoor heat exchanger 83 is drawn into the compressor 81 via the four-way selector valve 82.

[0043] (Regarding the control section) The air conditioning system 10 includes a control unit 60 that controls the operation of the air conditioning system 10. The control unit 60 includes an outdoor control unit (first control unit) 61 arranged in the outdoor unit 40, and an indoor control unit (third control unit) 62 arranged in the indoor unit 30. The outdoor control unit 61 and the indoor control unit 62 are connected to each other via a transmission line so that they can communicate with each other.

[0044] The outdoor control unit 61 is a device that controls the operation of the outdoor unit 40, and is configured, for example, by a microcomputer equipped with a processor such as a CPU, and memories such as RAM and ROM. The outdoor control unit 61 may be realized as hardware using an LSI, an ASIC, an FPGA, etc. The outdoor control unit 61 performs predetermined functions by having the processor execute a program installed in the memory. In the following description, the outdoor control unit 61 provided in the first outdoor unit 41 is referred to as the first outdoor control unit 61A. The detected values of each sensor provided in the first outdoor unit 41 are input to the first outdoor control unit 61A. The first outdoor control unit 61A controls the operation of the outdoor expansion valve 84, the compressor 81, the outdoor fan 87, etc. based on the detected values of each sensor, etc.

[0045] The indoor control unit 62 is a device that controls the operation of the indoor unit 30, and is configured, for example, by a microcomputer equipped with a processor such as a CPU, and memories such as RAM and ROM. The indoor control unit 62 may be realized as hardware using an LSI, an ASIC, an FPGA, or the like. The indoor control unit 62 performs predetermined functions by having the processor execute programs installed in the memory. The detected values of each sensor provided in the indoor unit 30 are input to the indoor control unit 62. The indoor control unit 62 controls the operation of the indoor unit 30 based on the detected values of each sensor, etc. The indoor control unit 62 is connected to a remote control 36 that the user uses to start and stop the indoor unit 30, change the set temperature, etc.

[0046] (Air conditioner operation modes) The air conditioner 20 has a first control mode M1 and a second control mode M2 as control modes M selectable by the control unit 60. The first control mode M1 is the control mode M selected by the control unit 60 when the air conditioning system 10 does not include a valve unit 50. The second control mode M2 is the control mode M selected by the control unit 60 when the air conditioning system 10 includes a valve unit 50. Note that the air conditioner 20 may further have control modes M other than the first control mode M1 and the second control mode M2 as control modes M selectable by the control unit 60.

[0047] (About selection methods) The control unit 60 has a selection means 37 for manually selecting the control mode M. By operating the selection means 37, the user of the air conditioning system 10 can manually select the control mode M instead of having the control unit 60 select the control mode M. In the air conditioner 20 of the present disclosure, a dip switch is provided on the control board (not shown) of the outdoor control unit 61, and this serves as the selection means 37. Note that the selection means 37 may be omitted in the air conditioning system 10. Although the present disclosure illustrates an example in which the selection means 37 is provided in the outdoor control unit 61, the selection means 37 may also be provided in the indoor control unit 62.

[0048] (Regarding the second air conditioning system) FIG. 5 is a refrigerant circuit diagram of an air conditioning system according to a second embodiment of the present disclosure. FIG. 6 is a block diagram of an air conditioning system according to the second embodiment of the present disclosure. As shown in FIGS. 1B, 5, and 6, the second air conditioning system 12 includes a second air conditioner 22. The second air conditioner 22 includes an indoor unit 30, an outdoor unit 40, and a valve unit 50 (shutoff valve unit 51). The second air conditioner 22 uses a flammable refrigerant (e.g., R32, which is slightly flammable) as the refrigerant, and is therefore provided with a shutoff valve unit 51 that shuts off the refrigerant supplied to the indoor unit 30. The second air conditioner 22 differs from the first air conditioner 21 in that it includes the shutoff valve unit 51. In other words, the second air conditioner 22 has the same configuration as the first air conditioner 21 except for the shutoff valve unit 51. In the second air conditioner 22 shown in Figures 5 and 6, parts that have a common configuration with the first air conditioner 21 are given the same symbols, and explanations of these common parts will be omitted unless otherwise specified.

[0049] (Shut-off valve unit) As shown in FIGS. 5 and 6 , the shutoff valve unit 51 includes a first electric valve 52 and a second electric valve 53. The first electric valve 52 and the second electric valve 53 are electric valves. The first electric valve 52 is provided in the liquid pipe 25L, and the pressure of the liquid refrigerant flowing through the liquid pipe 25L can be adjusted by adjusting the aperture of the first electric valve 52. The first electric valve 52 can shut off the flow of liquid refrigerant in the liquid pipe 25L by fully closing the aperture of the first electric valve 52. The second electric valve 53 is provided in the gas pipe 25G, and can shut off the flow of gaseous refrigerant in the gas pipe 25G by fully closing the aperture of the second electric valve 53. In other words, the shutoff valve unit 51 is a valve unit 50 that switches the flow of refrigerant to the indoor unit 30 between "open" and "closed."

[0050] (Regarding the control unit of the second air conditioning system) In the second air conditioning system 12, the control unit 60 includes a first outdoor control unit 61A, an indoor control unit 62, and a shutoff valve control unit 63. The first outdoor control unit 61A, the indoor control unit 62, and the shutoff valve control unit 63 are connected to each other via a transmission line so that they can communicate with each other.

[0051] (Shut-off valve control section) The shutoff valve control section (second control section) 63 is a device that controls the operation of the shutoff valve unit 51, and is configured, for example, by a microcomputer equipped with a processor such as a CPU and memories such as RAM and ROM. The shutoff valve control section 63 may be realized as hardware using an LSI, an ASIC, an FPGA, or the like. The shutoff valve control section 63 performs a predetermined function when the processor executes a program installed in the memory. The first motor-operated valve 52 and the second motor-operated valve 53 are connected to the shutoff valve control section 63. The shutoff valve control section 63 controls the operation of the first motor-operated valve 52 and the second motor-operated valve 53 based on, for example, detection values of sensors (not shown) that the indoor unit 30 and the first outdoor unit 41 have. Note that the shutoff valve control section 63 may be omitted in the second air conditioning system 12. In this case, the operation of the first motor-operated valve 52 and the second motor-operated valve 53 is controlled by the first outdoor control section 61A and / or the indoor control section 62.

[0052] In the second air conditioning system 12, when a refrigerant sensor (not shown) installed in the indoor unit 30 detects refrigerant, the shut-off valve control unit 63 closes the first electric valve 52 and the second electric valve 53 to cut off the supply of refrigerant to the indoor unit 30.

[0053] In the second air conditioning system 12, the first electric valve 52 is used as a control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30. The shutoff valve control unit 63 adjusts the opening of the first electric valve 52 based on detection values, etc., of sensors (not shown) that the indoor unit 30 and the first outdoor unit 41 have, to control the pressure of the refrigerant supplied to the indoor unit 30. In the second air conditioning system 12, by using the first electric valve 52 of the shutoff valve unit 51 (valve unit 50) as the control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30, it is possible to use an indoor unit 30 that does not have an internal electric valve (indoor expansion valve). Note that, in this embodiment, the control entity for adjusting the pressure of the refrigerant supplied to the indoor unit 30 is illustrated as being the shutoff valve control unit 63 of the control unit 60, but this is not limited thereto, and the first outdoor control unit 61A and the indoor control unit 62 may also be the control entity.

[0054] (Regarding the third air conditioning system) Fig. 7 is a refrigerant circuit diagram of an air conditioning system according to a third embodiment of the present disclosure. Fig. 8 is a block diagram of an air conditioning system according to a third embodiment of the present disclosure. As shown in Figs. 2A, 7, and 8, the third air conditioning system 13 includes a third air conditioner 23.

[0055] The third air conditioner 23 includes an indoor unit 30, a second outdoor unit 42, and a valve unit 50. The valve unit 50 included in the third air conditioner 23 is a refrigerant flow path switching unit 55. The third air conditioner 23 includes a refrigerant circuit RC2. The refrigerant circuit RC2 circulates refrigerant between the second outdoor unit 42 and the indoor unit 30. The refrigerant circuit RC2 includes a heat source side refrigerant circuit RC2A, a usage side refrigerant circuit RC2B, and an intermediate refrigerant circuit RC2C, which will be described later. The third air conditioner 23 has two or more indoor units 30 connected to one second outdoor unit 42. Each indoor unit 30 is connected to the second outdoor unit 42 via the refrigerant flow path switching unit 55. The third air conditioner 23 can freely select cooling operation or heating operation for each indoor unit 30 using the refrigerant flow path switching unit 55 to air-condition the target space.

[0056] (Configuration of the second outdoor unit) 7, various devices are disposed inside the second outdoor unit 42, and these devices are connected via refrigerant piping to form a heat-source-side refrigerant circuit RC2A. The heat-source-side refrigerant circuit RC2A is connected to an intermediate refrigerant circuit RC2C in the refrigerant flow path switching unit 55 via refrigerant piping 25 (liquid pipe 25L, high- and low-pressure gas pipe 25G1, and suction gas pipe 25G2).

[0057] The heat source side refrigerant circuit RC2A includes a liquid side shut-off valve 101, a first gas side shut-off valve 102, a second gas side shut-off valve 103, an accumulator 104, a compressor 105, a first flow path switching valve 106, a second flow path switching valve 107, a third flow path switching valve 108, an outdoor heat exchanger 109, a first outdoor expansion valve 110, and a second outdoor expansion valve 111. The second outdoor unit 42 further includes an outdoor fan 112, an outdoor control unit 61 (see FIG. 8), etc.

[0058] The liquid-side shutoff valve 101, the gas-side first shutoff valve 102, and the gas-side second shutoff valve 103 are manual valves that are opened and closed during refrigerant charging, pumping down, etc. One end of the liquid-side shutoff valve 101 is connected to the liquid pipe 25L. The other end of the liquid-side shutoff valve 101 is connected to refrigerant piping extending to the first outdoor expansion valve 110 and the second outdoor expansion valve 111. One end of the gas-side first shutoff valve 102 is connected to the high / low pressure gas pipe 25G1. The other end of the gas-side first shutoff valve 102 is connected to refrigerant piping extending to the second flow path switching valve 107. One end of the gas-side second shutoff valve 103 is connected to the suction gas pipe 25G2. The other end of the gas-side second shutoff valve 103 is connected to refrigerant piping extending to the accumulator 104.

[0059] The accumulator 104 is a container for temporarily storing the low-pressure refrigerant sucked into the compressor 105 and separating the refrigerant into a gaseous state and a liquid state.

[0060] The compressor 105 has a sealed structure with a built-in compressor motor, and is, for example, a positive displacement compressor such as a scroll type or rotary type. The compressor 105 compresses low-pressure refrigerant drawn in through a suction pipe 105b and then discharges the refrigerant from a discharge pipe 105a. Refrigerating machine oil is contained inside the compressor 105. This refrigerating machine oil may circulate within the refrigerant circuit together with the refrigerant. The second outdoor unit 42 of this embodiment is equipped with one compressor 105, but may also be equipped with two or more compressors 105 connected in parallel.

[0061] The first flow path switching valve 106, the second flow path switching valve 107, and the third flow path switching valve 108 are four-way switching valves. The first flow path switching valve 106, the second flow path switching valve 107, and the third flow path switching valve 108 switch the flow of refrigerant depending on the operating status of the third air conditioner 23. A discharge pipe 105a or a branch pipe extending from the discharge pipe 105a is connected to one refrigerant inlet of the first flow path switching valve 106, the second flow path switching valve 107, and the third flow path switching valve 108. A branch pipe extending from the refrigerant pipe 105c connecting the second gas-side shut-off valve 103 and the accumulator 104 is connected to one refrigerant inlet of the first flow path switching valve 106, the second flow path switching valve 107, and the third flow path switching valve 108. The first flow path switching valve 106, the second flow path switching valve 107, and the third flow path switching valve 108 are configured to block the flow of refrigerant in one refrigerant flow path during operation, and in effect function as a three-way valve.

[0062] The outdoor heat exchanger 109 is a cross-fin type or microchannel type heat exchanger. The outdoor heat exchanger 109 includes a first heat exchange section 109a and a second heat exchange section 109b. The first heat exchange section 109a is provided in an upper portion of the outdoor heat exchanger 109, and the second heat exchange section 109b is provided below the first heat exchange section 109a.

[0063] A gas side end of the first heat exchanger 109a is connected to a refrigerant pipe extending to the third flow path switching valve 108. A liquid side end of the first heat exchanger 109a is connected to a refrigerant pipe extending to the first outdoor expansion valve 110.

[0064] A gas side end of the second heat exchanger 109b is connected to a refrigerant pipe extending to the first flow path switching valve 106. A liquid side end of the second heat exchanger 109b is connected to a refrigerant pipe extending to the second outdoor expansion valve 111.

[0065] The refrigerant passing through the first heat exchange section 109a and the second heat exchange section 109b exchanges heat with an airflow generated by the outdoor fan 112. The outdoor fan 112 is, for example, a propeller fan, and is driven by an outdoor fan motor (not shown). The outdoor fan 112 generates an airflow that flows into the second outdoor unit 42, passes through the outdoor heat exchanger 109, and flows out of the second outdoor unit 42.

[0066] The first outdoor expansion valve 110 and the second outdoor expansion valve 111 are, for example, motor-operated valves with adjustable opening degrees. One end of the first outdoor expansion valve 110 is connected to a refrigerant pipe extending from the first heat exchanger 109a. The other end of the first outdoor expansion valve 110 is connected to a refrigerant pipe extending to the liquid-side shut-off valve 101.

[0067] One end of the second outdoor expansion valve 111 is connected to a refrigerant pipe extending from the second heat exchanger 109b. The other end of the second outdoor expansion valve 111 is connected to a refrigerant pipe extending to the liquid-side shut-off valve 101. The openings of the first outdoor expansion valve 110 and the second outdoor expansion valve 111 are adjusted according to the operating conditions, and the refrigerant passing through the insides is reduced in pressure according to the openings.

[0068] The operation of the compressor 105, the outdoor fan 112, the first outdoor expansion valve 110, the second outdoor expansion valve 111, the first flow path switching valve 106, the second flow path switching valve 107, and the third flow path switching valve 108 is controlled by an outdoor control unit 61 (see FIG. 8). In the following description, the outdoor control unit 61 provided in the second outdoor unit 42 will be referred to as a second outdoor control unit 61B.

[0069] (indoor unit) The third air conditioner 23 has the same indoor unit 30 as the first and second air conditioners 21, 22. A detailed description of the indoor unit 30 in the third air conditioner 23 will be omitted. A utilization-side refrigerant circuit RC2B is provided within the indoor unit 30. The utilization-side refrigerant circuit RC2B is configured by connecting an indoor heat exchanger 31 by a liquid pipe 25L and a gas pipe 25G.

[0070] (Refrigerant flow path switching unit) As shown in Figures 7 and 8, the third air conditioner 23 has a refrigerant flow path switching unit 55. The refrigerant flow path switching unit 55 is provided between the second outdoor unit 42 and the multiple indoor units 30. The refrigerant flow path switching unit 55 has a casing 56. The refrigerant flow path switching unit 55 switches the flow of refrigerant flowing into the second outdoor unit 42 and each indoor unit 30. The refrigerant flow path switching unit 55 is a valve unit 50 that switches the flow of refrigerant to the indoor units 30 for each indoor unit 30. As shown in Figure 7, the casing 56 houses multiple header pipes 155, 156, 157, 158 and multiple switching units 57.

[0071] (Header pipe) 7, the multiple header pipes 155, 156, 157, 158 include a first header pipe 155, a second header pipe 156, a third header pipe 157, and a fourth header pipe 158. The first header pipe 155 is connected to the liquid pipe 25L. The second header pipe 156 is connected to the high / low pressure gas pipe 25G1. The third header pipe 157 is connected to the intake gas pipe 25G2.

[0072] (Switching unit) The refrigerant flow path switching unit 55 includes a plurality of switching units 57. Each switching unit 57 forms an intermediate refrigerant circuit RC2C of the refrigerant flow path switching unit 55. One indoor unit 30 is connected to each switching unit 57. However, it is not necessary for all switching units 57 of the refrigerant flow path switching unit 55 to be connected to an indoor unit 30, and the refrigerant flow path switching unit 55 may include a switching unit 57 to which no indoor unit 30 is connected.

[0073] (Intermediate refrigerant circuit) The plurality of switching units 57 all have the same structure, and the intermediate refrigerant circuit RC2C of each switching unit 57 includes a plurality of valves EV1, EV2, EV3, EV4 and a plurality of refrigerant pipes.

[0074] In the switching unit 57, the multiple valves EV1, EV2, EV3, and EV4 include a first valve EV1, a second valve EV2, a third valve EV3, and a fourth valve EV4. These valves EV1, EV2, EV3, and EV4 are configured as motor-operated valves with adjustable opening degrees. The second valve EV2, the third valve EV3, and the fourth valve EV4 are controlled by a flow path switching control unit 64 (see FIG. 8) to assume any one of a fully closed state, a fully open state, and an opening degree adjustment state. The first valve EV1 is controlled by the flow path switching control unit 64 (see FIG. 8) to assume any one of a minimum opening state, a fully open state, a fully closed state, and an opening degree adjustment state.

[0075] The switching unit 57 includes a first refrigerant pipe P1 that connects the second header pipe 156 and the first valve EV1. A filter F1 is provided midway along the first refrigerant pipe P1. The switching unit 57 includes a second refrigerant pipe P2. One end of the second refrigerant pipe P2 is connected to the first valve EV1. The switching unit 57 includes a usage-side gas pipe 161. One end of the usage-side gas pipe 161 is connected to the gas pipe 25G of the indoor unit 30. The other end of the usage-side gas pipe 161 is connected to the second valve EV2. The other end of the second refrigerant pipe P2 is connected to the usage-side gas pipe 161. A filter F2 is provided in the usage-side gas pipe 161.

[0076] The switching unit 57 includes a third refrigerant pipe P3. One end of the third refrigerant pipe P3 is connected to the second valve EV2. The other end of the third refrigerant pipe P3 is connected to a third header pipe 157. A filter F3 is provided midway along the third refrigerant pipe P3.

[0077] The switching unit 57 is equipped with a utilization side liquid pipe 162. One end of the utilization side liquid pipe 162 is connected to a liquid pipe 25L of the indoor unit 30. The other end of the utilization side liquid pipe 162 is connected to a subcooling heat exchanger 159. A fourth valve EV4 is provided midway along the utilization side liquid pipe 162. A first heat transfer pipe 159a and a second heat transfer pipe 159b are provided inside the subcooling heat exchanger 159. The subcooling heat exchanger 159 exchanges heat between the refrigerant flowing through the first heat transfer pipe 159a and the refrigerant flowing through the second heat transfer pipe 159b. The other end of the utilization side liquid pipe 162 is connected to one end of the first heat transfer pipe 159a.

[0078] The switching unit 57 includes a fourth refrigerant pipe P4. One end of the fourth refrigerant pipe P4 is connected to the other end of the first heat transfer pipe 159a. The other end of the fourth refrigerant pipe P4 is connected to the first header pipe 155.

[0079] The switching unit 57 includes a fifth refrigerant pipe P5 that branches off from the fourth refrigerant pipe P4. One end of the fifth refrigerant pipe P5 is connected to one end of the third valve EV3. A filter F4 is provided in the fifth refrigerant pipe P5.

[0080] The switching unit 57 includes a sixth refrigerant pipe P6 and a seventh refrigerant pipe P7. One end of the sixth refrigerant pipe P6 is connected to the third valve EV3. The other end of the sixth refrigerant pipe P6 is connected to one end of the second heat transfer pipe 159b of the subcooling heat exchanger 159. One end of the seventh refrigerant pipe P7 is connected to the second heat transfer pipe 159b of the subcooling heat exchanger 159. The other end of the seventh refrigerant pipe P7 is connected to a fourth header pipe 158. The fourth header pipe 158 is connected to the third header pipe 157 via a connecting pipe 163.

[0081] The refrigerant flows into the fourth header pipe 158 from the first header pipe 155 via the fourth refrigerant pipe P4, the fifth refrigerant pipe P5, the third valve EV3, the sixth refrigerant pipe P6, the subcooling heat exchanger 159, and the seventh refrigerant pipe P7. The refrigerant that has flowed into the fourth header pipe 158 passes through the connecting pipe 163 and flows into the third header pipe 157.

[0082] (Regarding the control unit of the third air conditioning system) The control unit 60 in the third air conditioning system 13 includes a second outdoor control unit 61B, an indoor control unit 62, and a flow path switching control unit 64 of the refrigerant flow path switching unit 55. The second outdoor control unit 61B, the indoor control unit 62, and the flow path switching control unit 64 are connected to each other via a transmission line so that they can communicate with each other.

[0083] The second outdoor control unit 61B is a device that controls the operation of the second outdoor unit 42. The detection values of each sensor provided in the second outdoor unit 42 are input to the second outdoor control unit 61B. Based on the detection values of each sensor, etc., the second outdoor control unit 61B controls the operation of the compressor 105, the outdoor fan 112, the first outdoor expansion valve 110, the second outdoor expansion valve 111, the first flow path switching valve 106, the second flow path switching valve 107, the third flow path switching valve 108, etc.

[0084] The flow path switching control unit (second control unit) 64 is a device that controls the operation of the refrigerant flow path switching unit 55, and is configured, for example, by a microcomputer equipped with a processor such as a CPU and memories such as RAM and ROM. The flow path switching control unit 64 may be realized as hardware using an LSI, an ASIC, an FPGA, or the like. The flow path switching control unit 64 performs predetermined functions by having the processor execute a program installed in the memory. The flow path switching control unit 64 controls the operation of the first valve EV1, the second valve EV2, the third valve EV3, and the fourth valve EV4 based on the detected values of the sensors of the second outdoor unit 42 and the indoor unit 30. Note that the flow path switching control unit 64 may be omitted in the third air conditioning system 13. In this case, the operation of each valve EV1 to EV4 is controlled by the second outdoor control unit 61B and / or the indoor control unit 62.

[0085] For example, if the third air conditioning system 13 uses a flammable refrigerant and a refrigerant sensor (not shown) provided in the indoor unit 30 detects the refrigerant, the flow path switching control unit 64 may fully close the first valve EV1, the second valve EV2, and the fourth valve EV4 to cut off the supply of refrigerant to the indoor unit 30. In this case, the amount of refrigerant leaking from the indoor unit 30 can be suppressed without providing a shutoff valve unit 51 (see FIG. 1B).

[0086] In the third air conditioning system 13, the fourth valve EV4 is used as a control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30. The flow path switching control unit 64 adjusts the opening degree of the fourth valve EV4 based on detection values, etc., of sensors (not shown) included in the indoor unit 30 and the second outdoor unit 42, to control the pressure of the refrigerant supplied to the indoor unit 30. In the third air conditioning system 13, the fourth valve EV4 of the refrigerant flow path switching unit 55 (valve unit 50) is used as a control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30, making it possible to use an indoor unit 30 that does not have an internal motor-operated valve (indoor expansion valve). Note that, in the present embodiment, the flow path switching control unit 64 of the control unit 60 is used as the control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30, but this is not limited to this, and the second outdoor control unit 61B and the indoor control unit 62 may also be used.

[0087] (Operation of the third air conditioning system) Below, we will explain the cases where the third air conditioning system 13 is used when all of the operating indoor units 30 perform cooling (hereinafter also referred to as "full cooling operation"), when all of the operating indoor units 30 perform heating (hereinafter also referred to as "full heating operation"), and when some of the operating indoor units 30 perform cooling and others perform heating (hereinafter also referred to as "mixed cooling and heating operation").

[0088] (Full cooling operation) In the full cooling operation, the control unit 60 adjusts each valve as follows: The first valve EV1 of the switching unit 57 is fully closed, the second valve EV2 is fully open, the third valve EV3 and the fourth valve EV4 have their openings adjusted, and the first and second outdoor expansion valves 110, 111 are fully open. The first flow path switching valve 106 of the second outdoor unit 42 is switched to connect the discharge pipe 105a of the compressor 105 to the gas side end of the second heat exchanger 109b. The second flow path switching valve 107 is switched to connect the discharge pipe 105a to the high / low pressure gas pipe 25G1. The third flow path switching valve 108 is switched to connect the discharge pipe 105a to the gas side end of the first heat exchanger 109a.

[0089] When the compressor 105 is driven, the high-pressure gas refrigerant compressed by the compressor 105 passes through the discharge pipe 105a, the first flow path switching valve 106, the third flow path switching valve 108, etc., and flows into the outdoor heat exchanger 109, where it is condensed. The refrigerant condensed in the outdoor heat exchanger 109 passes through the first and second outdoor expansion valves 110, 111, the liquid side stop valve 101, etc., and flows into the liquid pipe 25L.

[0090] The refrigerant that has flowed into the liquid pipe 25L flows through the first header pipe 155 of the refrigerant flow path switching unit 55, and flows into the fourth refrigerant pipe P4 of each switching unit 57. The refrigerant that has flowed into the fourth refrigerant pipe P4 flows into the first heat transfer pipe 159a of the subcooling heat exchanger 159, and is further decompressed by the fourth valve EV4 on the user-side liquid pipe 162 before flowing into the indoor unit 30.

[0091] The refrigerant that has flowed into the fourth refrigerant pipe P4 also branches off to flow into the fifth refrigerant pipe P5, where it is decompressed according to the opening of the third valve EV3 and flows into the second heat transfer pipe 159b of the subcooling heat exchanger 159. In this subcooling heat exchanger 159, heat is exchanged between the refrigerant flowing through the first heat transfer pipe 159a and the refrigerant flowing through the second heat transfer pipe 159b, and the refrigerant flowing through the first heat transfer pipe 159a is subcooled and flows into the indoor unit 30.

[0092] The refrigerant flowing through the second heat transfer pipe 159b of the subcooling heat exchanger 159 flows from the seventh refrigerant pipe P7 into the fourth header pipe 158, passes through the connecting pipe 163, and flows into the third header pipe 157. The refrigerant that has flowed into the indoor unit 30 evaporates in the indoor heat exchanger 31.

[0093] In the indoor unit 30, the refrigerant evaporated in the indoor heat exchanger 31 flows from the gas pipe 25G into the user-side gas piping 161, passes mainly through the second valve EV2, and flows into the third header pipe 157. The refrigerant that has flowed into the third header pipe 157 passes through the suction gas pipe 25G2 and the gas-side second shut-off valve 103, flows into the accumulator 104, and is sucked into the compressor 105.

[0094] (All heating operation) In heating only operation, the control unit 60 adjusts each valve as follows: The first valve EV1 of the switching unit 57 is fully opened, the second valve EV2 is fully closed, the third valve EV3 is fully closed, the fourth valve EV4 is fully opened, and the opening degrees of the first and second outdoor expansion valves 110, 111 are adjusted. The first flow path switching valve 106 of the second outdoor unit 42 is switched to connect the refrigerant pipe 105c to the gas side end of the second heat exchanger 109b. The second flow path switching valve 107 is switched to connect the discharge pipe 105a to the high / low pressure gas pipe 25G1. The third flow path switching valve 108 is switched to connect the refrigerant pipe 105c to the gas side end of the first heat exchanger 109a.

[0095] When the compressor 105 is driven, the high-pressure gas refrigerant compressed by the compressor 105 flows into the high-low pressure gas pipe 25G1 via the discharge pipe 105a and the second flow path switching valve 107. The refrigerant that has flowed into the high-low pressure gas pipe 25G1 passes through the second header pipe 156 of the refrigerant flow path switching unit 55 and the first refrigerant pipe P1 of the switching unit 57, passes through the first valve EV1, and flows from the usage-side gas pipe 161 into the gas pipe 25G of the indoor unit 30.

[0096] The refrigerant that has flowed into the gas pipe 25G flows into the indoor heat exchanger 31 of the indoor unit 30 and condenses. The condensed refrigerant flows through the liquid pipe 25L, passes through the fourth valve EV4, and flows into the utilization-side liquid pipe 162 of the switching unit 57. The refrigerant that has flowed into the utilization-side liquid pipe 162 passes through the subcooling heat exchanger 159 and the fourth refrigerant pipe P4, and flows into the first header pipe 155.

[0097] The refrigerant that has flowed into the first header pipe 155 flows through the liquid pipe 25L and into the second outdoor unit 42, where it is decompressed in the first and second outdoor expansion valves 110, 111. The decompressed refrigerant evaporates when passing through the outdoor heat exchanger 109, passes through the first flow path switching valve 106, the third flow path switching valve 108, etc., flows into the accumulator 104, and is sucked into the compressor 105.

[0098] (mixed cooling and heating operation) In the cooling / heating combined operation, the control unit 60 adjusts each valve as follows. In the switching unit 57 (hereinafter also referred to as the "cooling-side switching unit 57") corresponding to the indoor unit 30 performing cooling operation (hereinafter also referred to as the "cooling-side indoor unit 30") among the operating indoor units 30, the first valve EV1 is set to the minimum opening, the second valve EV2 is fully open, and the openings of the third valve EV3 and the fourth valve EV4 are adjusted. The first flow path switching valve 106 of the second outdoor unit 42 is switched to connect the refrigerant pipe 105c to the gas side end of the second heat exchanger 109b. The second flow path switching valve 107 is switched to connect the discharge pipe 105a to the high / low pressure gas pipe 25G1. The third flow path switching valve 108 is switched to connect the discharge pipe 105a to the gas side end of the first heat exchanger 109a.

[0099] In the switching unit 57 (hereinafter also referred to as the "heating side switching unit 57") corresponding to the indoor unit 30 performing heating operation (hereinafter also referred to as the "heating side indoor unit 30") among the operating indoor units 30, the first valve EV1 is fully open, the second valve EV2 is fully closed, the third valve EV3 is fully closed, and the fourth valve EV4 is fully open.

[0100] When the compressor 105 is driven, a portion of the high-pressure gas refrigerant compressed by the compressor 105 passes through the discharge pipe 105a and the second flow path switching valve 107 and flows into the high-low pressure gas pipe 25G1. Another portion of the high-pressure gas refrigerant compressed by the compressor 105 passes through the discharge pipe 105a and the third flow path switching valve 108 and is condensed in the first heat exchanger 109a. Some of the refrigerant passes through the first outdoor expansion valve 110 and flows into the liquid pipe 25L, and the remainder flows into the second outdoor expansion valve 111. The refrigerant condensed in the first heat exchanger 109a passes through the second outdoor expansion valve 111 and evaporates in the second heat exchanger 109b, and is sucked into the compressor 105 through the first flow path switching valve 106.

[0101] The refrigerant that flows into the high / low pressure gas pipe 25G1 flows into the second header pipe 156 of the refrigerant flow path switching unit 55, flows through the first refrigerant pipe P1 of the heating side switching unit 57, the first valve EV1, and the usage side gas piping 161, and flows into the gas pipe 25G.

[0102] The refrigerant that has flowed into the gas pipe 25G is condensed in the indoor heat exchanger 31 of the heating-side indoor unit 30. The condensed refrigerant flows from the liquid pipe 25L through the fully opened fourth valve EV4 into the use-side liquid piping 162 of the heating-side switching unit 57, then flows through the subcooling heat exchanger 159 and the fourth refrigerant pipe P4, and into the first header pipe 155.

[0103] The refrigerant that flows into the liquid pipe 25L from the second outdoor unit 42 also flows into the first header pipe 155. The refrigerant that flows into the first header pipe 155 passes through the fourth refrigerant pipe P4 of the cooling-side switching unit 57, the subcooling heat exchanger 159, and the use-side liquid piping 162, is depressurized by the fourth valve EV4 whose opening is adjusted, and then flows through the liquid pipe 25L into the cooling-side indoor unit 30. At this time, the refrigerant that has passed through the subcooling heat exchanger 159 branches off from the fourth refrigerant pipe P4, flows through the fifth refrigerant pipe P5, and is subcooled by the refrigerant that has been depressurized by the third valve EV3.

[0104] The refrigerant that flows into the cooling-side indoor unit 30 evaporates in the indoor heat exchanger 31, cooling the room. The evaporated refrigerant flows through the gas pipe 25G, flows into the use-side gas piping 161 of the cooling-side switching unit 57, passes through the second valve EV2, flows into the third refrigerant pipe P3 and the third header pipe 157, flows through the suction gas pipe 25G2, flows into the accumulator 104, and is sucked into the compressor 105.

[0105] (Regarding the 4th air conditioning system) FIG. 9 is a refrigerant circuit diagram of an air conditioning system according to a fourth embodiment of the present disclosure. FIG. 10 is a block diagram of an air conditioning system according to the fourth embodiment of the present disclosure. As shown in FIGS. 2B, 9, and 10, a fourth air conditioning system 14 includes a fourth air conditioner 24. The fourth air conditioner 24 includes an indoor unit 30, an outdoor unit 40, and multiple valve units 50 (shutoff valve units 51 and refrigerant flow path switching units 55). The fourth air conditioner 24 uses a flammable refrigerant (e.g., slightly flammable R32) as the refrigerant, and is therefore provided with a shutoff valve unit 51 that shuts off the refrigerant supplied to the indoor unit 30. The fourth air conditioner 24 differs from the third air conditioner 23 in that it includes the shutoff valve unit 51. In other words, the fourth air conditioner 24 has the same configuration as the third air conditioner 23 except for the shutoff valve unit 51. In the fourth air conditioner 24 shown in Figures 9 and 10, parts that have a common configuration with the third air conditioner 23 are given the same symbols, and explanations of these common parts will be omitted unless otherwise specified.

[0106] (Regarding the control unit of the fourth air conditioning system) In the fourth air conditioning system 14, the control unit 60 includes a second outdoor control unit 61B, an indoor control unit 62, a shutoff valve control unit 63, and a flow path switching control unit 64. The second outdoor control unit 61B, the indoor control unit 62, the shutoff valve control unit 63, and the flow path switching control unit 64 are connected to each other via transmission lines so that they can communicate with each other.

[0107] In the fourth air conditioning system 14, when a refrigerant sensor (not shown) installed in the indoor unit 30 detects refrigerant, the shut-off valve control unit 63 closes the first electric valve 52 and the second electric valve 53 to cut off the supply of refrigerant to the indoor unit 30.

[0108] In the fourth air conditioning system 14, the fourth valve EV4 is used as a control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30. In this embodiment, the flow path switching control unit 64 of the control unit 60 adjusts the opening degree of the fourth valve EV4 based on the detected values of each sensor (not shown) that the indoor unit 30 and the first outdoor unit 41 have, and controls the pressure of the refrigerant supplied to the indoor unit 30.

[0109] In the second air conditioning system 12, the first electric valve 52 may be used as a control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30. In this case, the shutoff valve control unit 63 adjusts the opening degree of the first electric valve 52 based on detection values, etc., of sensors (not shown) included in the indoor unit 30 and the first outdoor unit 41, to control the pressure of the refrigerant supplied to the indoor unit 30. In the fourth air conditioning system 14, by using the fourth valve EV4 of the refrigerant flow path switching unit 55 or the first electric valve 52 of the shutoff valve unit 51 as the control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30, it is possible to use an indoor unit 30 that does not have an internal electric valve (indoor expansion valve). Note that, in the present embodiment, the control valve for adjusting the pressure of the refrigerant supplied to the indoor unit 30 is controlled by the shutoff valve control unit 63 or the flow path switching control unit 64 of the control unit 60, but this is not limited thereto, and the second outdoor control unit 61B and the indoor control unit 62 may also be the control unit.

[0110] (Regarding the control mode selection operation by the control unit) Figure 11 is a control flow diagram of the control unit in the air conditioning system of the present disclosure. In the air conditioning system 10 of the present disclosure, the control unit 60 performs the operation shown in Figure 11 when the power is turned on for the first time after installation is complete. In the air conditioning system 10 of the present disclosure, the outdoor control unit 61 performs the operation shown in Figure 11. Note that the timing for performing the operation shown in Figure 11 is not limited to when the power is turned on for the first time.

[0111] When the operation shown in FIG. 11 starts, the control unit 60 first executes step (S01). In step (S01), the control unit 60 determines whether or not the air conditioning system 10 has a valve unit 50. If the air conditioning system 10 does not have a valve unit 50 (if No), the control unit 60 then executes step (S02). If the air conditioning system 10 has a valve unit 50 (if Yes), the control unit 60 then executes step (S05). Note that in the second air conditioning system 12 described above, the motor-operated valves 52, 53 of the shutoff valve unit 51 may be used exclusively for shutting off the refrigerant. If the motor-operated valves 52, 53 are used exclusively for shutting off the refrigerant in the second air conditioning system 12, the control unit 60 does not determine that the shutoff valve unit 51 is a valve unit 50 in step (S01).

[0112] In step (S02), the control unit 60 selects the first control mode M1 as the control mode M of the air conditioner 20, and then executes step (S03).

[0113] In step (S03), the control unit 60 writes information about the outdoor unit 40 to the indoor control unit 62. In this case, the control unit 60 writes information that the outdoor unit 40 is the first outdoor unit 41 (in other words, information that the air conditioning system 10 is of the first specification) to the indoor control unit 62. After executing step (S02), the control unit 60 then executes step (S04).

[0114] In step (S04), the control unit 60 controls the air conditioner 20 in the first control mode M1. In this case, the outdoor control unit 61 controls the outdoor expansion valve 84 to adjust the pressure of the refrigerant supplied to the indoor unit 30. Note that this step (S04) is performed when the air conditioning system 10 is the first air conditioning system 11 (see Figures 3 and 4). In the first air conditioning system 11, the indoor control unit 62 controls the operation of the indoor unit 30 based on information about the first outdoor unit 41 written to the indoor control unit 62.

[0115] In step (S05), the control unit 60 selects the second control mode M2 as the control mode M of the air conditioner 20, and then executes step (S06).

[0116] In step (S06), the control unit 60 determines whether or not the air conditioning system 10 has a refrigerant flow path switching unit 55. If the air conditioning system 10 does not have a refrigerant flow path switching unit 55 (No), the control unit 60 then executes step (S07). If the air conditioning system 10 has a refrigerant flow path switching unit 55 (Yes), the control unit 60 then executes step (S09).

[0117] In step (S07), the control unit 60 writes information about the outdoor unit 40 to the indoor control unit 62. In this case, the control unit 60 writes information that the outdoor unit 40 is the first outdoor unit 41 (in other words, information that the air conditioning system 10 is of the first specification) to the indoor control unit 62. After executing step (S07), the control unit 60 then executes step (S08).

[0118] In step (S08), the control unit 60 controls the air conditioner 20 in the second control mode M2. In this case, the shutoff valve control unit 63 controls the first electric valve 52 to adjust the pressure of the refrigerant supplied to the indoor unit 30. Note that this step (S08) is performed when the air conditioning system 10 is the second air conditioning system 12 (see FIGS. 5 and 6). In the second air conditioning system 12, the indoor control unit 62 controls the operation of the indoor unit 30 based on information about the first outdoor unit 41 written to the indoor control unit 62.

[0119] In step (S09), the control unit 60 writes information about the outdoor unit 40 to the indoor control unit 62. In this case, the control unit 60 writes information that the outdoor unit 40 is the second outdoor unit 42 (in other words, information that the air conditioning system 10 is of the second specification) to the indoor control unit 62. After executing step (S09), the control unit 60 then executes step (S10).

[0120] In step (S10), the control unit 60 controls the air conditioner 20 in the second control mode M2. In this case, the flow path switching control unit 64 controls the fourth valve EV4 to adjust the pressure of the refrigerant supplied to the indoor unit 30. Note that this step (S10) is executed when the air conditioning system 10 is the third air conditioning system 13 (see Figures 7 and 8) or the fourth air conditioning system 14 (see Figures 9 and 10). In the third air conditioning system 13 and the fourth air conditioning system 14, the indoor control unit 62 controls the operation of the indoor unit 30 based on information about the second outdoor unit 42 written to the indoor control unit 62.

[0121] In the air conditioning system 10 of the present disclosure, after the operations of steps (S01) to (S10) described above, the control unit 60 determines the specifications (presence or absence of a valve unit 50, and the air conditioning method) of the air conditioning system 10. In the air conditioning system 10, the control unit 60 selects the control mode M of the air conditioner 20 according to the specifications, making it possible to use a common indoor unit 30.

[0122] In this embodiment, the operations of the above steps (S01) to (S10) are performed by the outdoor control unit 61 provided in the outdoor unit 40, but the operations may also be performed by the indoor control unit 62 provided in the indoor unit 30. Furthermore, the operations of the above steps (S01) to (S10) may also be performed by a control unit 60 other than the outdoor control unit 61 and the indoor control unit 62. For example, if the air conditioning system 10 has a central monitoring device (not shown) or a management server connected via the Internet, the central monitoring device or the management server may be included in the control unit 60, and the operations of the above steps (S01) to (S10) may be performed by the central monitoring device or the management server.

[0123] [Effects of the embodiment] (1) The outdoor unit 40 of the present disclosure is provided in an air conditioning system 10 including refrigerant circuits RC1, RC2 that perform a refrigeration cycle and multiple indoor units 30, and the multiple indoor units 30 are connected in parallel. The outdoor unit 40 is provided with a first control valve (outdoor expansion valve 84, or first outdoor expansion valve 110 and second outdoor expansion valve 111) that adjusts the pressure of the refrigerant supplied to the indoor units 30, and an outdoor control unit 61 that controls the first control valve (outdoor expansion valve 84, or first outdoor expansion valve 110 and second outdoor expansion valve 111). When the air conditioning system 10 does not include a valve unit 50 that is provided between the indoor units 30 and the outdoor unit 40 and switches the flow of refrigerant to the indoor units 30, the outdoor control unit 61 controls the outdoor expansion valve 84 to operate the air conditioning system 10 in a first control mode M1 that adjusts the pressure of the refrigerant supplied to the indoor units 30. When the valve unit 50 is included in the air conditioning system 10, the air conditioning system 10 is operated in a second control mode M2, which controls the second control valve (first electric valve 52 or fourth valve EV4) included in the valve unit 50 to adjust the pressure of the refrigerant supplied to the indoor unit 30.

[0124] When an outdoor unit 40 configured in this manner is used, the control unit 60 can switch the control mode M of the air conditioner 20 according to the specifications of the air conditioning system 10, such that when the air conditioning system 10 is of the first specification, the control unit 60 controls the outdoor expansion valve 84 of the outdoor unit 40, and when the air conditioning system 10 is of the second specification, the control unit 60 controls the fourth valve EV4 of the refrigerant flow path switching unit 55. This eliminates the need to provide a control valve in the indoor unit 30 even when the air conditioning system 10 is of the second specification, and makes it possible to use a common indoor unit 30 that does not have a control valve, regardless of the specifications of the air conditioning system 10.

[0125] (2) The indoor units 30 of the present disclosure are provided in an air conditioning system 10 including refrigerant circuits RC1, RC2 that perform a refrigeration cycle and an outdoor unit 40, and are connected in parallel to the outdoor unit 40 in multiple units. The outdoor unit 40 is provided with a first control valve (outdoor expansion valve 84, or first outdoor expansion valve 110 and second outdoor expansion valve 111) that adjusts the pressure of the refrigerant supplied to the indoor unit 30. The indoor unit 30 is provided with an indoor control unit 62 that controls the first control valve (outdoor expansion valve 84, or first outdoor expansion valve 110 and second outdoor expansion valve 111). When the air conditioning system 10 does not include a valve unit 50 that is provided between the indoor unit 30 and the outdoor unit 40 and switches the flow of refrigerant to the indoor unit 30, the indoor control unit 62 controls the outdoor expansion valve 84 to operate the air conditioning system 10 in a first control mode M1 that adjusts the pressure of the refrigerant supplied to the indoor unit 30. When the valve unit 50 is included in the air conditioning system 10, the indoor control unit 62 controls the second control valve (first electric valve 52 or fourth valve EV4) included in the valve unit 50 to operate the air conditioning system 10 in a second control mode M2 that adjusts the pressure of the refrigerant supplied to the indoor unit 30.

[0126] When an indoor unit 30 with this configuration is used, the control mode M of the air conditioner 20 can be switched by the indoor control unit 62 according to the specifications of the air conditioning system 10, such that when the air conditioning system 10 is of the first specification, the control unit 60 controls the outdoor expansion valve 84 of the outdoor unit 40, and when the air conditioning system 10 is of the second specification, the control unit 60 controls the fourth valve EV4 of the refrigerant flow path switching unit 55. This eliminates the need to provide a control valve in the indoor unit 30 even when the air conditioning system 10 is of the second specification, and makes it possible to use a common indoor unit 30 that does not have a control valve, regardless of the specifications of the air conditioning system 10.

[0127] (3) The air conditioning system 10 of the present disclosure includes refrigerant circuits RC1 and RC2 that perform a refrigeration cycle, an outdoor unit 40, and a plurality of indoor units 30 connected in parallel to the outdoor unit 40. The air conditioning system 10 includes a control unit 60 that controls the operation of the air conditioning system 10. The outdoor unit 40 includes a first control valve (an outdoor expansion valve 84, or a first outdoor expansion valve 110 and a second outdoor expansion valve 111) that adjusts the pressure of the refrigerant supplied to the indoor units 30. If the air conditioning system 10 does not include a valve unit 50 that is provided between the indoor units 30 and the outdoor unit 40 and switches the flow of refrigerant to the indoor units 30, the air conditioning system 10 operates in a first control mode M1 that controls the outdoor expansion valve 84 to adjust the pressure of the refrigerant supplied to the indoor units 30. When the valve unit 50 is included in the air conditioning system 10, the air conditioning system 10 operates in a second control mode M2 in which the second control valve (first electric valve 52) or the fourth valve EV4 included in the valve unit 50 is controlled to adjust the pressure of the refrigerant supplied to the indoor unit 30.

[0128] In an air conditioning system 10 configured as described above, when the air conditioning system 10 is of the first specification, the control unit 60 controls the outdoor expansion valve 84 of the outdoor unit 40, and when the air conditioning system 10 is of the second specification, the control unit 60 controls the fourth valve EV4 of the refrigerant flow path switching unit 55, and so on. In this way, the outdoor control unit 61 can switch the control mode M of the air conditioner 20 according to the specifications of the air conditioning system 10. This eliminates the need to provide a control valve in the indoor unit 30 even when the air conditioning system 10 is of the second specification, and makes it possible to use a common indoor unit 30 that does not have a control valve, regardless of the specifications of the air conditioning system 10.

[0129] (4) In the air conditioning system 10 of the present disclosure, the control unit 60 automatically selects the second control mode M2 when the valve unit 50 is included in the air conditioning system 10. In this case, simply by connecting the valve unit 50 to the indoor unit 30 and the outdoor unit 40, the second control mode M2 suitable for the specifications of the air conditioning system 10 can be automatically selected.

[0130] (5) The air conditioning system 10 of the present disclosure further includes a selection means 37 for manually selecting the first control mode M1 and the second control mode M2. In this case, the user can manually select the first control mode M1 or the second control mode M2.

[0131] (6) In the air conditioning system 10 of the present disclosure, when the valve unit 50 is not included in the air conditioning system 10, the control unit 60 (outdoor control unit 61) controls the outdoor expansion valve 84 in the first control mode M1. In the air conditioning system 10, when the valve unit 50 is included in the air conditioning system 10, the control unit 60 (shutoff valve control unit 63 and / or flow path switching control unit 64) controls the first electric valve 52 or the fourth valve MV4 in the second control mode M2. In this case, the control unit 60 can automatically select the first control mode M1 or the second control mode M2.

[0132] (7) In the air conditioning system 10 of the present disclosure, in the third air conditioning system 13 including the valve unit 50, if a refrigerant leaks in the indoor unit 30, the fourth valve EV4 cuts off the supply of refrigerant to the indoor unit 30. In this case, the fourth valve EV4 can be used as a control valve that adjusts the pressure of the refrigerant, and also as a shutoff valve that cuts off the refrigerant. In such an air conditioning system 10, there is no need to provide a separate shutoff valve, which reduces manufacturing costs.

[0133] (8) In the air conditioning system 10 of the present disclosure, the control unit 60 further includes an indoor control unit 62 that controls the operation of the indoor unit 30, and the indoor unit 30 has the indoor control unit 62. When the indoor unit 30 and the outdoor unit 40 are connected, information about the outdoor unit 40 is written to the indoor control unit 62, and the indoor control unit 62 controls the indoor unit 30 based on the information about the outdoor unit 40. In this case, simply by connecting the indoor unit 30 and the outdoor unit 40, the control content of the indoor unit 30 can be automatically switched to content that corresponds to the specifications of the outdoor unit 40.

[0134] It should be noted that the present disclosure is not limited to the above examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0135] 10: Air conditioning system 11: First air conditioning system 12: Second air conditioning system 13: Third air conditioning system 14: 4th air conditioning system 20: Air conditioner 30: Indoor unit 40:Outdoor unit 50: Valve unit 51:Shut-off valve unit (valve unit) 52: First electric valve (second control valve) 55: Refrigerant flow path switching unit (valve unit) 60: Control section 62: Indoor control unit 84: Outdoor expansion valve (first control valve) 110: First outdoor expansion valve (first control valve) 111: Second outdoor expansion valve (first control valve) EV4: 4th valve (2nd control valve) RC1: Refrigerant circuit RC2: Refrigerant circuit M: Control mode M1: First control mode M2: Second control mode

Claims

1. An outdoor unit (40) provided in an air conditioning system (10) including refrigerant circuits (RC1, RC2) that perform a refrigeration cycle and a plurality of indoor units (30), the plurality of indoor units (30) being connected in parallel, the outdoor unit (40) includes a first control valve (84, 110, 111) that adjusts the pressure of the refrigerant supplied to the indoor unit (30), and a control unit (60) that controls the first control valve (84, 110, 111), The control unit (60) When the air conditioning system (10) does not include a valve unit (50) that is provided between the indoor unit and the outdoor unit and switches the flow of refrigerant to the indoor unit (30), the air conditioning system (10) is operated in a first control mode (M1) that controls the first control valve (84) to adjust the pressure of the refrigerant supplied to the indoor unit (30), When the valve unit (50) is included in the air conditioning system (10) and the air conditioning system (10) is capable of individually selecting, from among the plurality of indoor units (30), an indoor unit (30) to perform cooling operation and an indoor unit (30) to perform heating operation, the outdoor unit (40) operates the air conditioning system (10) in a second control mode (M2) that controls a second control valve (52, EV4) included in the valve unit (50) to adjust the pressure of the refrigerant supplied to the indoor unit (30).

2. An air conditioning system (10) including a refrigerant circuit (RC1, RC2) that performs a refrigeration cycle and an outdoor unit (40), wherein a plurality of indoor units (30) are connected in parallel to the outdoor unit (40), the outdoor unit (40) is provided with a first control valve (84, 110, 111) that adjusts the pressure of the refrigerant supplied to the indoor unit (30); the indoor unit (30) is provided with a control unit (60) that controls the first control valve (84, 110, 111); The control unit (60) When the air conditioning system (10) does not include a valve unit (50) that is provided between the indoor unit and the outdoor unit and switches the flow of refrigerant to the indoor unit (30), the air conditioning system (10) is operated in a first control mode (M1) that controls the first control valve (84) to adjust the pressure of the refrigerant supplied to the indoor unit (30), When the valve unit (50) is included in the air conditioning system (10) and the air conditioning system (10) is capable of individually selecting, from among the plurality of indoor units (30), an indoor unit (30) to perform cooling operation and an indoor unit (30) to perform heating operation, the indoor unit (30) operates the air conditioning system (10) in a second control mode (M2) that controls a second control valve (52, MV4) included in the valve unit (50) to adjust the pressure of the refrigerant supplied to the indoor unit (30).

3. An air conditioning system (10) including a refrigerant circuit (RC1, RC2) that performs a refrigeration cycle, an outdoor unit (40), and a plurality of indoor units (30) connected in parallel to the outdoor unit (40), The air conditioning system (10) includes a control unit (60) that controls the operation of the air conditioning system (10), the outdoor unit (40) is provided with a first control valve (84, 110, 111) that adjusts the pressure of the refrigerant supplied to the indoor unit (30); a first control mode (M1) for controlling the first control valve (84) to adjust the pressure of the refrigerant supplied to the indoor unit (30) when the air conditioning system (10) does not include a valve unit (50) that is provided between the indoor unit and the outdoor unit and switches the flow of refrigerant to the indoor unit (30); and a second control mode (M2) for controlling a second control valve (52, MV4) included in the valve unit (50) to adjust the pressure of the refrigerant supplied to the indoor units (30), when the valve unit (50) is included in the air conditioning system (10) and the air conditioning system (10) is capable of individually selecting, from among the plurality of indoor units (30), an indoor unit (30) that performs cooling operation and an indoor unit (30) that performs heating operation.

4. The control unit (60) The air conditioning system (10) of claim 3, wherein the second control mode (M2) is automatically selected when the valve unit (50) is included in the air conditioning system (10).

5. 5. The air conditioning system (10) according to claim 3 or claim 4, further comprising a selection means (37) for manually selecting the first control mode (M1) and the second control mode (M2).

6. When the valve unit (50) is not included in the air conditioning system (10), the control unit (60) controls the first control valve (84) in the first control mode (M1); 4. The air conditioning system (10) of claim 3, wherein when the valve unit (50) is included in the air conditioning system (10), the control unit (60) controls the second control valve (52, MV4) in the second control mode (M2).

7. The air conditioning system (10) according to any one of claims 3 to 6, wherein in the air conditioning system (13) including the valve unit (50), if a refrigerant leaks from the indoor unit (30), the second control valve (MV4) cuts off the supply of refrigerant to the indoor unit (30).

8. the control unit (60) includes an indoor control unit (62) that controls the operation of the indoor unit (30), and the indoor unit (30) has the indoor control unit (62), When the indoor unit (30) and the outdoor unit (40) are connected, information about the outdoor unit (40) is written to the indoor control unit (62), The air conditioning system (10) according to any one of claims 3 to 7, wherein the indoor control unit (62) controls the indoor unit (30) based on information from the outdoor unit (40).

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