CN113874661A

CN113874661A - Air conditioning system

Info

Publication number: CN113874661A
Application number: CN202080038527.7A
Authority: CN
Inventors: 中山和博; 冈本敦
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2019-05-28
Filing date: 2020-04-08
Publication date: 2021-12-31
Anticipated expiration: 2040-04-08
Also published as: JP6844731B2; US20220146173A1; CN113874661B; EP3978817A1; JP2020197370A; WO2020241076A1; EP3978817A4; EP3978817B1

Abstract

An air conditioning system (100) is provided with a Refrigerant Cycle (RC), a power supply unit (40), a controller (60), and a determination unit (90). A Refrigerant Cycle (RC) includes an outdoor unit (10) and a plurality of indoor units (30). The outdoor unit (10) includes a compressor (11). The power supply unit (40) supplies auxiliary power to at least a part of the plurality of indoor units (30) when the power supply to at least a part of the plurality of indoor units is cut off. The controller (60) controls at least the compressor (11). The determination unit (90) determines whether to stop the compressor (11) or to continue the operation of the compressor (11) when the power supply to at least a part of the plurality of indoor units (10) is cut off. The determination unit (90) transmits a command corresponding to the determination to the controller (60).

Description

Air conditioning system

Technical Field

An air conditioning system capable of performing an air conditioning operation even when the power supply of some indoor units is cut off.

Background

Patent document 1 (japanese patent application laid-open No. 2013-40698) discloses an air conditioner that can perform an air conditioning operation even if the power supply of some of the indoor units is cut off.

Disclosure of Invention

Technical problem to be solved by the invention

In some air conditioning systems, a power supply unit is provided to supply power to an indoor unit whose power supply is cut off. However, there is a limit to the power that can be supplied by such a power supply unit. There is a possibility that a problem such as breakage of a compressor in the outdoor unit or overflow of drain water in the indoor unit may occur.

Technical scheme for solving technical problem

An air conditioning system according to a first aspect includes a refrigerant cycle, a power supply unit, a controller, and a determination unit. The refrigerant cycle includes an outdoor unit and a plurality of indoor units. The outdoor unit includes a compressor. The power supply unit supplies auxiliary power to at least a part of the plurality of indoor units when the power supply to at least a part of the plurality of indoor units is cut off. The controller controls at least the compressor. The determination unit determines whether to stop the compressor or to continue the operation of the compressor when the power supply to at least a part of the plurality of indoor units is cut off. The judgment unit transmits a command corresponding to the judgment to the controller.

An air conditioning system according to a second aspect is the air conditioning system according to the first aspect, wherein the determination unit performs the determination based on at least one of: a prediction of the degree of humidification or degree of humidification of the refrigerant drawn by the compressor; and a drain water amount or a prediction of the drain water amount of at least a part of the plurality of indoor units.

An air conditioning system according to a third aspect is the air conditioning system according to the second aspect, wherein the determination unit determines the air conditioning system based on the amount of drain water or the prediction of the amount of drain water in at least a part of the plurality of indoor units, and the power supply capacity of the power supply unit.

An air conditioning system according to a fourth aspect is the air conditioning system according to any one of the first to third aspects, wherein the controller causes at least the compressor to perform the oil return operation or the defrosting operation in the refrigerant cycle. In the air conditioning system according to any one of the first to third aspects, the determination unit determines whether or not to continue the oil-return operation or the defrosting operation when the power supply unit supplies the auxiliary power to at least a part of the air conditioning system.

An air conditioning system according to a fifth aspect is the air conditioning system according to the fourth aspect, wherein when the controller performs the oil-return operation in the refrigerant cycle, the controller stops the compressor when the determination unit determines that the oil-return operation is not to be continued.

An air conditioning system according to a sixth aspect is the air conditioning system according to the fifth aspect, wherein the controller stops the compressor in accordance with a degree of humidification of the refrigerant sucked by the compressor.

An air conditioning system according to a seventh aspect is the air conditioning system according to the fourth aspect, wherein each of the plurality of indoor units includes an expansion valve. The controller divides the plurality of indoor units into at least two groups. When the determination unit determines that the oil-return operation is to be continued while the controller is performing the oil-return operation in the refrigerant cycle, the controller sequentially performs the first-group sealing control and the second-group sealing control. In the first group closing control, the expansion valves of the indoor units belonging to the first group are closed, and the expansion valves of the indoor units belonging to the second group are opened. In the second group closing control, the expansion valves of the indoor units belonging to the first group are opened, and the expansion valves of the indoor units belonging to the second group are closed.

An air conditioning system of an eighth aspect is the air conditioning system of any one of the fourth to seventh aspects, wherein the outdoor unit further includes a four-way selector valve. When the controller executes the defrosting operation in the refrigerant cycle, the controller stops the compressor when the determination unit determines that the defrosting operation is not to be continued.

An air conditioning system of a ninth aspect is the air conditioning system of the seventh aspect, wherein the outdoor unit further includes a four-way selector valve. When the controller executes the defrosting operation in the refrigerant cycle, the controller switches the four-way selector valve when the determination unit determines that the defrosting operation is to be continued.

An air conditioning system according to a tenth aspect is the air conditioning system according to the ninth aspect, wherein when the controller switches the four-way selector valve, at least one of the plurality of expansion valves is opened, and the compressor is operated.

Drawings

Fig. 1 is a schematic configuration diagram of an air conditioning system 100 according to an embodiment.

Fig. 2 is a diagram illustrating a control flow of the operation of the entire air conditioning system 100.

Fig. 3 is a flowchart of the M/T control in the oil return operation.

Fig. 4 is a flowchart of the M/T control in the defrosting operation.

Fig. 5 is a schematic configuration diagram of an air conditioning system 100 according to modification a.

Fig. 6 is a flowchart of the M/T control in the oil return operation according to modification a.

Fig. 7 is a flowchart of the M/T control in the defrosting operation according to modification B.

Fig. 8 is a schematic configuration diagram of an air conditioning system 100 according to modification C.

Fig. 9 is a flowchart of the M/T control during the operation of the air conditioning system 100 according to modification D.

Detailed Description

(1) Structure of air conditioning system 100

Fig. 1 is a schematic configuration diagram of an air conditioning system 100 according to the present embodiment. The air conditioning system 100 is a system for performing air conditioning such as cooling or heating in a target space included in a building such as a house, a high-rise building, a factory, or a public facility.

The air conditioning system 100 includes a refrigerant circuit RC through which a refrigerant circulates. The air conditioning system 100 circulates a refrigerant in the refrigerant circuit RC to perform a refrigeration cycle of a vapor compression method, thereby cooling or heating a target space. The refrigerant circuit RC contains a refrigerant such as R410A, R32, or ammonia.

The air conditioning system 100 mainly includes: an outdoor unit 10 as a heat source unit; a plurality of (three in fig. 1) indoor units 30(30a, 30b, and 30c) as usage units; a power supply unit 40; a plurality of (three in fig. 1) remote controllers 50; and a controller 60. The outdoor unit 10 and each of the indoor units 30 are connected to each other via a gas communication pipe GP and a liquid communication pipe LP to constitute a refrigerant circuit RC of the air conditioning system 100. In other words, the air conditioning system 100 is a multi-connected (multi-tenant) air conditioning system in which a plurality of indoor units 30 are connected to the same refrigerant system.

(1-1) outdoor Unit 10

The outdoor unit 10 is an outdoor unit installed outdoors (outside the target space). The outdoor unit 10 mainly has: a plurality of refrigerant pipes (first pipe P1 to fifth pipe P5); a compressor 11; a four-way reversing valve 12; an outdoor heat exchanger 13; an outdoor fan 15; an outdoor unit control unit 17; and a determination section 90.

The first pipe P1 is a refrigerant pipe that connects the gas communication pipe GP and the four-way selector valve 12. The second pipe P2 is a suction pipe that connects the four-way selector valve 12 and a suction port (not shown) of the compressor 11. The third pipe P3 is a discharge pipe that connects a discharge port (not shown) of the compressor 11 and the four-way selector valve 12. The fourth pipe P4 is a refrigerant pipe that connects the four-way selector valve 12 and the gas side of the outdoor heat exchanger 13. The fifth pipe P5 is a refrigerant pipe that connects the liquid side of the outdoor heat exchanger 13 and the liquid communication pipe LP.

The compressor 11 is a mechanism that sucks in, compresses, and discharges a low-pressure gas refrigerant. The compressor 11 has a sealed structure in which a compressor motor 11a is incorporated. In the compressor 11, a compressor motor 11a serves as a drive source for driving a rotary or scroll-type compression element (not shown) housed in a compressor housing (not shown). The compressor motor 11a is controlled by frequency conversion during operation, and the rotation speed is adjusted according to the situation. The compressor 11, when driven, sucks in refrigerant from a suction port, compresses the refrigerant, and discharges the refrigerant from a discharge port.

The four-way selector valve 12 is a valve for switching the flow direction of the refrigerant in the refrigerant circuit RC. The four-way selector valve 12 is connected to a first pipe P1, a second pipe P2, a third pipe P3, and a fourth pipe P4, respectively. The four-way selector valve 12 switches the flow paths so that the first pipe P1 and the second pipe P2 are connected and the third pipe P3 and the fourth pipe P4 are connected during the cooling operation (see the solid lines of the four-way selector valve 12 in fig. 1). The four-way selector valve 12 switches the flow paths so that the first pipe P1 and the third pipe P3 are connected and the second pipe P2 and the fourth pipe P4 are connected during the heating operation (see the broken lines of the four-way selector valve 12 in fig. 1).

The outdoor heat exchanger 13 is a heat exchanger that functions as a condenser or a radiator of the refrigerant during the cooling operation and functions as an evaporator or a heat absorber of the refrigerant during the heating operation. The outdoor heat exchanger 13 includes a heat transfer pipe (not shown) through which the refrigerant flows and heat transfer fins (not shown) that increase the heat transfer area. The outdoor heat exchanger 13 is configured to exchange heat between the refrigerant in the heat transfer pipe and the air flow generated by the outdoor fan 15 during operation.

The outdoor fan 15 is, for example, a propeller fan. The outdoor fan 15 is connected to an output shaft of an outdoor fan motor 15a, and is driven in conjunction with the outdoor fan motor 15 a. When driven, the outdoor fan 15 generates an air flow that flows into the outdoor unit 10 from the outside, passes through the outdoor heat exchanger 13, and flows out of the outdoor unit 10.

The outdoor unit control unit 17 is a microcomputer including a CPU, a memory, and the like. The outdoor unit control unit 17 controls the operation of each actuator of the outdoor unit 10. The outdoor-unit controller 17 and an indoor-unit controller 34 (described later) of each indoor unit 30 are connected to each other via communication lines cb1, cb2 and the power supply unit 40, and transmit and receive signals to and from each other.

The determination unit 90 is a microcomputer including a CPU, a memory, and the like. The determination section 90 can communicate with the outdoor unit control section 17. When the power supply unit 40 is operated, the determination unit 90 determines whether or not to continue the oil return operation or the defrosting operation. The operation of the determination unit 90 will be described later.

(1-2) indoor Unit 30

The indoor units 30(30a, 30b, and 30c) are indoor units installed in the target space. The indoor unit 30 constitutes a refrigerant circuit RC together with the outdoor unit 10. The indoor unit 30 mainly has: the indoor heat exchanger 31; an expansion valve 32(32a, 32b, 32 c); an indoor fan 33; and an indoor unit control unit 34.

The indoor heat exchanger 31 is a heat exchanger that functions as an evaporator or a heat absorber of the refrigerant during the cooling operation and functions as a condenser or a radiator of the refrigerant during the heating operation. The indoor heat exchanger 31 is, for example, a cross fin tube heat exchanger. The liquid side of the indoor heat exchanger 31 is connected to refrigerant pipes extending to the expansion valves 32(32a, 32b, 32 c). The gas side of the indoor heat exchanger 31 is connected to a refrigerant pipe extending to the gas communication pipe GP. The indoor heat exchanger 31 is disposed so as to exchange heat between the refrigerant in the heat transfer pipe (not shown) and the air flow generated by the indoor fan 33 during operation.

The expansion valves 32(32a, 32b, 32c) are electrically operated valves with adjustable opening degrees. The expansion valve 32 adjusts the opening degree appropriately according to the situation during operation, and reduces the pressure of the refrigerant according to the opening degree. Each indoor unit 30 has one expansion valve 32. Specifically, the indoor unit 30a has an expansion valve 32a, the indoor unit 30b has an expansion valve 32b, and the indoor unit 30c has an expansion valve 32 c. The opening degrees of the

expansion valves

32a, 32b, and 32c are appropriately adjusted according to the operating conditions of the corresponding

indoor units

30a, 30b, and 30c, respectively.

The expansion valve 32 is connected to a refrigerant pipe extending to the liquid side of the indoor heat exchanger 31 and a refrigerant pipe extending to the liquid communication pipe LP. The liquid communication pipe LP is connected to the fifth pipe P5 and each expansion valve 32 of the outdoor unit 10. One end of the liquid communication pipe LP is connected to the fifth pipe P5, and the other end of the liquid communication pipe LP branches off in accordance with the number of expansion valves 32 and is connected to each expansion valve 32.

The indoor fan 33 is a blower such as a turbo fan, a sirocco fan, a cross flow fan, or a propeller fan. The indoor fan 33 is connected to an output shaft of an indoor fan motor 33 a. The indoor fan 33 is driven in conjunction with an indoor fan motor 33 a. When driven, the indoor fan 33 generates an air flow that is drawn into the indoor unit 30, passes through the indoor heat exchanger 31, and is blown out to the target space.

The indoor unit control unit 34 is a microcomputer including a CPU, a memory, and the like. The indoor unit control unit 34 controls the operation of each actuator of the indoor unit 30. Each indoor-unit controller 34 and each outdoor-unit controller 17 are connected to each other via communication lines cb1, cb2 and power supply unit 40, and transmit and receive signals to and from each other. The indoor-unit control unit 34 wirelessly communicates with the remote controller 50.

The indoor unit controller 34 of the indoor unit 30 is connected to the expansion valve 32 of the indoor unit 30 via a communication line (not shown), and is capable of adjusting the opening degree of the expansion valve 32.

(1-3) Power supply Unit 40

The power feeding unit 40 is connected to the outdoor unit controller 17 and each indoor unit controller 34 via communication lines cb1 and cb 2. Specifically, the communication line cb1 connects the power supply unit 40 to the outdoor unit controllers 17, and the communication lines cb2 branch off in accordance with the number of indoor unit controllers 34, and connect the power supply unit 40 to each of the indoor unit controllers 34. The communication line cb1 is connected to the communication line cb2 via the power supply unit 40.

Each indoor unit 30 is connected to an external commercial power supply (not shown) provided in the building. The indoor unit 30 operates by electric power supplied from a commercial power supply during normal operation. The power supply unit 40 is an auxiliary power supply as follows: when the commercial power supply to at least a part of the plurality of indoor units 30 is cut off, in other words, when the power supply from the commercial power supply to at least one indoor unit 30 is stopped, the indoor unit 30 to which the commercial power supply (hereinafter, simply referred to as "power supply") is cut off is supplied with power. The communication line cb2 transmits, in addition to signals transmitted and received between the outdoor-unit control unit 17 and each indoor-unit control unit 34, electric power supplied from the power supply unit 40 to each indoor unit 30.

(1-4) remote controller 50

The remote controller 50 is a device having a remote controller control unit (not shown) including a microcomputer including a CPU and a memory, and a remote controller input unit (not shown) including input keys for inputting various commands to the air conditioning system 100.

The air conditioning system 100 has the same number of remote controllers 50 as the indoor units 30. The remote controllers 50 correspond one-to-one to any one of the indoor units 30. The remote controller 50 wirelessly communicates with the indoor unit control unit 34 of the corresponding indoor unit 30 using infrared rays, radio waves, or the like. When a user, a manager, or the like inputs an instruction to the remote controller input unit, the remote controller 50 transmits a predetermined signal to the indoor unit control unit 34 according to the input instruction.

(1-5) controller 60

In the air conditioning system 100, the controller 60 is configured by connecting the outdoor unit controller 17 of the outdoor unit 10 to the indoor unit controllers 34 of the indoor units 30(30a, 30b, and 30c) via the communication lines cb1 and cb2 and the power supply unit 40. The controller 60 controls the operation of the air conditioning system 100.

(2) Operation of air conditioning system 100

When an operation start command is input to any one of the remote controllers 50 and the controller 60 controls the cooling operation or the heating operation, the four-way selector valve 12 is switched to a predetermined state, and the compressor 11 and the outdoor fan 15 are started. Then, the indoor unit 30 corresponding to the remote controller 50 to which the operation start command is input is set to the operating state (the state in which the indoor fan 33 is operated).

(2-1) Cooling operation

During the cooling operation, the four-way selector valve 12 is switched to the refrigeration cycle state (the state indicated by the solid line of the four-way selector valve 12 in fig. 1). When each actuator is activated in the above state, the refrigerant is sucked into the compressor 11 through the second pipe P2 and compressed. The refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 13 through the third pipe P3, the four-way selector valve 12, and the fourth pipe P4.

The refrigerant flowing into the outdoor heat exchanger 13 exchanges heat with the air flow generated by the outdoor fan 15, and condenses (or dissipates heat). The refrigerant flowing out of the outdoor heat exchanger 13 flows into each indoor unit 30 through the fifth pipe P5 and the liquid communication pipe LP.

The refrigerant flowing into the indoor unit 30 flows into the expansion valve 32. The refrigerant flowing into the expansion valve 32 is decompressed in accordance with the opening degree of the expansion valve 32. The refrigerant flowing out of the expansion valve 32 flows into the indoor heat exchanger 31, exchanges heat with the air flow generated by the indoor fan 33, and evaporates (or absorbs heat). The refrigerant flowing out of the indoor heat exchanger 31 passes through the gas communication pipe GP and flows into the outdoor unit 10.

The refrigerant flowing into the outdoor unit 10 passes through the first pipe P1, the four-way selector valve 12, and the second pipe P2, is again sucked into and compressed by the compressor 11.

(2-2) heating operation

During the heating operation, the four-way selector valve 12 is switched to the heating cycle state (the state indicated by the broken line in the four-way selector valve 12 in fig. 1). When each actuator is activated in the above state, the refrigerant is sucked into the compressor 11 through the second pipe P2 and compressed. The refrigerant discharged from the compressor 11 flows into each indoor unit 30 through the third pipe P3, the four-way selector valve 12, the first pipe P1, and the gas communication pipe GP.

The refrigerant flowing into the indoor unit 30 flows into the indoor heat exchanger 31, exchanges heat with the air flow generated by the indoor fan 33, and condenses (or dissipates heat). The refrigerant flowing out of the indoor heat exchanger 31 flows into the expansion valve 32, and is decompressed in accordance with the opening degree of the expansion valve 32. The refrigerant flowing out of the expansion valve 32 flows into the outdoor unit 10 through the liquid communication pipe LP.

The refrigerant flowing into the outdoor unit 10 passes through the fifth pipe P5 and flows into the outdoor heat exchanger 13. The refrigerant flowing into the outdoor heat exchanger 13 exchanges heat with the air flow generated by the outdoor fan 15 and evaporates (or is extremely hot). The refrigerant flowing out of the outdoor heat exchanger 13 passes through the fourth pipe P4, the four-way selector valve 12, and the second pipe P2, is again sucked into and compressed by the compressor 11.

(2-3) oil-Return operation

The oil-return operation circulates the refrigerant so as to return the lubricating oil dispersed in the refrigerant circuit RC to the compressor 11. In the oil return operation, the expansion valve 32 is opened to circulate the refrigerant. During the oil return operation, the indoor fan 33 may be stopped.

(2-4) defrosting operation

The defrosting operation melts frost generated in the outdoor heat exchanger 13 by the heating operation. During the defrosting operation, the four-way selector valve 12 is switched to the refrigeration cycle state. During the defrosting operation, the indoor fan 33 is stopped.

(3) Normal control mode and M/T control mode

Fig. 2 shows a control flow of the operation of the entire air conditioning system 100. As shown in fig. 2, the entire air conditioning system 100 is operated in a normal control mode or a multi-tenant control mode (hereinafter, referred to as an "M/T control mode").

In the normal control mode, normal operation control is performed, which is also used in a conventional system including one outdoor unit and one indoor unit. In the normal control mode, the power supply of all the indoor units 30 of the air conditioning system 100 is not cut off, and the power supply is received from an external power supply. In the normal control mode, the air conditioning system 100 starts the air conditioning operation and shifts from the stopped state to the steady state (a state in which the operation control in the normal state is performed) or stops the air conditioning operation and shifts from the steady state to the stopped state by an operation of the remote controller 50 or the like. When the steady state is shifted to the stopped state, the oil return operation and the defrosting operation are performed as necessary.

When the power supply of at least a part of the indoor units 30 is cut off, the air conditioning system 100 operating in the normal control mode shifts to the M/T control mode (see solid arrows in fig. 2). In the M/T control mode, at least one of the indoor units 30 is turned off to an operation stop state. In the M/T control mode, the indoor unit 30 whose power supply is cut off (hereinafter, referred to as "power-cut indoor unit 30") receives the supply of auxiliary power from the power supply unit 40.

(4) Details of M/T control mode

The operations of the controller 60 and the determination unit 90 when the power supply of the indoor unit 30 is turned off during each operation will be described.

(4-1) oil-Return operation

Fig. 3 is a flowchart of the M/T control mode when the power shutoff of the indoor unit 30 occurs during the oil return operation. The determination unit 90 determines whether or not to continue the oil-return operation based on the number of the power shutoff indoor units 30, the remaining required time of the oil-return operation, the power suppliable power of the power supply unit, and the like (S101)

When the determination unit 90 determines that the oil-return operation is to be continued (yes in S101), the controller 60 continues the oil-return operation (S102). On the other hand, when the determination unit 90 determines that the oil-return operation is not to be continued (no in S101), the controller 60 acquires the degree of humidification of the refrigerant sucked into the compressor 11 (S103).

Next, the controller 60 determines whether to stop the compressor 11 based on the acquired degree of humidification of the refrigerant (S104). If the controller 60 determines not to stop the compressor 11 (no in S104), the controller 60 returns to step S103. On the other hand, when the controller 60 determines to stop the compressor 11 (S104: YES), the controller stops the compressor 11.

(4-2) defrosting operation

Fig. 4 is a flowchart when power shutoff of the indoor unit 30 occurs during the defrosting operation. The determination unit 90 determines whether or not to continue defrosting based on the number of power shutoff indoor units 30, the remaining required time of defrosting operation, the power suppliable power of the power supply unit, and the like (S201).

When the determination unit 90 determines to continue the defrosting operation (yes in S201), the controller 60 continues the defrosting operation (S202). On the other hand, when the determination unit 90 determines that the defrosting operation is not to be continued (no in S201), the controller 60 stops the compressor 11.

When the defrosting operation is continued (S202), the same defrosting operation as in the normal control mode is performed. For example, in the heating operation, the expansion valve 32 is first closed, and then the four-way selector valve 12 is switched to the refrigeration cycle state. Then, the expansion valve 32 is opened. Thus, the noise generated by switching the four-way selector valve can be suppressed.

(5) Feature(s)

(5-1)

The determination unit 90 determines whether or not to continue the oil return operation or the defrosting operation. Therefore, even when the power supply cutoff of the indoor unit 30 occurs during the oil-return operation or the defrosting operation, if it is considered that the air conditioning system 100 is not damaged, the oil-return operation or the defrosting operation can be continuously performed.

(5-2)

When the determination unit 90 determines that the oil return operation or the defrosting operation is not to be continued, the controller 60 stops the compressor 11. Therefore, by stopping the operation of the entire air conditioning system 100 when the power supply cutoff indoor unit 30 is generated, damage to the air conditioning system 100 can be suppressed.

(5-3)

The controller 60 stops the compressor 11 according to the degree of humidification of the refrigerant sucked by the compressor 11. Therefore, the suction of a large amount of liquid refrigerant into the compressor 11 can be suppressed, and damage to the compressor 11 can be reduced.

(6) Modification example

A modification of the above embodiment will be described below. A plurality of embodiments may be combined.

(6-1) modification A

In the above embodiment, if the oil-return operation is continued when the power-off of the indoor unit 30 occurs, the oil-return operation is performed simultaneously for all the indoor units 30(30a to 30 c). Alternatively, the indoor units 30 may be divided into a plurality of groups, and the oil return operation may be performed sequentially for each group. In fig. 5, the indoor units 30 are divided into a first group G1(30a, 30b) and a second group (30 c).

As shown in fig. 6, when the determination unit 90 determines to continue the oil return operation (S101: yes), the controller 60 executes the first set of closing control (S102-1). In the first group closing control, the expansion valves 32(32a, 32b) of the indoor units 30(30a, 30b) belonging to the first group G1 are closed, and the expansion valve 32(32c) of the indoor unit 30(30c) belonging to the second group G2 is opened. In this state, the oil return operation is performed.

Next, the controller 60 executes a second set of close control (S102-2). In the second group closing control, the expansion valves 32(32a, 32b) of the indoor units 30(30a, 30b) belonging to the first group G1 are opened, and the expansion valve 32(32c) of the indoor unit 30(30c) belonging to the second group G2 is closed. In this state, the oil return operation is performed.

(6-2) modification B

In the above embodiment, if the defrosting operation is continued when the power shutoff of the indoor unit 30 is generated, the same defrosting operation as in the normal control mode is performed. Alternatively, the defrosting operation may be performed in the M/T control mode, which is different from the normal control mode.

For example, as shown in fig. 7, when the determination unit 90 determines to continue the defrosting operation during the heating operation (yes in S201), the controller 60 switches the four-way selector valve 12 to the refrigeration cycle state while keeping the expansion valve of the indoor unit 30 open (S202-1).

According to the above configuration, since the operation of closing the expansion valve for noise processing is omitted, the electric power supplied from the power supply unit 40 to the expansion valve 32 can be reduced.

(6-3) modification C

The outdoor unit 10 may also have other components not shown in fig. 1. Fig. 8 is a schematic configuration diagram of an air conditioning system 100 according to this modification. In fig. 8, the outdoor unit 10 further has an oil separator 14, an expansion valve 16, a receiver (receiver)18, and a storage tank (accumulator) 19.

The oil separator 14 is attached to the third pipe P3. The oil separator 14 removes the lubricating oil mixed in the refrigerant from the high-pressure gas refrigerant discharged from the compressor 11.

The expansion valve 16 is attached to the fifth pipe P5. The expansion valve 16 is an electrically operated valve whose opening degree can be adjusted. The expansion valve 16 appropriately adjusts the opening degree according to the situation when the air conditioning system 100 is operating, and decompresses the refrigerant according to the opening degree.

The receiver 18 is attached to the fifth pipe P5. The receiver 18 is installed between the expansion valve 16 and the liquid communication pipe LP. The receiver 18 temporarily stores the refrigerant in accordance with the operating state of the air conditioning system 100 to absorb a change in the amount of refrigerant in the outdoor heat exchanger 13 and the indoor heat exchanger 31. The receiver 18 may have a mechanism for removing moisture and foreign matter contained in the refrigerant circulating through the refrigerant circuit RC.

The tank 19 is attached to the second pipe P2. The accumulator 19 separates the gas-liquid mixed refrigerant flowing in the refrigerant circuit RC into a gas refrigerant and a liquid refrigerant, and delivers only the gas refrigerant to the suction port of the compressor 11.

In fig. 8, the outdoor unit 10 may not have the receiver 18 or the tank 19.

The contents described in the embodiment and the modifications a to B can be applied to the air conditioning system 100 shown in fig. 8.

(6-4) modification D

Fig. 9 shows an operation of the air conditioning system 100 according to modification D.

In any operation, when the power supply cutoff indoor unit 30 is generated, the M/T control mode is started (S300). Next, the controller 60 obtains the degree of humidification of the refrigerant sucked by the compressor 11 (S301). Next, the determination unit 90 determines whether or not the obtained degree of humidification of the refrigerant or future prediction based on the degree of humidification is abnormal (S302). If the abnormality occurs (yes in S302), the determination unit 90 transmits a command to the controller 60 to stop the compressor 11 (S305). This is to prevent breakage of the compressor 11. When the humidity level or the like is normal (no in S302), the controller 60 acquires opening degree information of the expansion valve of the power shutoff indoor unit 30 (S303). The determination unit 90 derives the amount of drain water in the power-off indoor unit 30 or a future prediction of the amount of drain water, based on the acquired opening degree information. Next, the determination unit 90 determines whether or not there is a possibility of overflow of the drain water in the power-off indoor unit 30 based on the derived value (S304). When the drain water may overflow (yes in S304), the determination unit 90 transmits a command to the controller 60 to stop the compressor 11 (S305). This is to prevent the drain water from overflowing in the power-off indoor unit 30. If there is no possibility of the drain water overflowing (no in S304), the process proceeds to step S100 or step S200 in the embodiment or the modification described above.

The contents described in the embodiment and the modifications a to C can also be applied to the air conditioning system 100 described with reference to the flowchart of fig. 9.

< statement >

While the embodiments of the present disclosure have been described above, it should be understood that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as set forth in the appended claims.

(symbol description)

10 outdoor unit

11 compressor

12 four-way change valve

30 indoor unit

32 expansion valve

40 power supply unit

60 controller

90 determination unit

100 air conditioning system

RC refrigerant circuit (refrigerant cycle)

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-40698.

Claims

1. An air conditioning system, comprising:

a Refrigerant Cycle (RC) including an outdoor unit (10) including a compressor (11) and a plurality of indoor units (30);

a power supply unit (40) that supplies auxiliary power to at least a part of the plurality of indoor units when power to the part is cut off;

a controller (60) that controls at least the compressor; and

and a determination unit (90) that, when the power supply to the at least a portion of the plurality of indoor units is cut off, performs one of a determination to stop the compressor and a determination to continue operating the compressor, and that transmits a command corresponding to the determination to the controller.

2. The air conditioning system of claim 1,

the determination unit performs the determination based on at least one of:

a degree of humidification or a prediction of the degree of humidification of refrigerant drawn by the compressor; and

a drain water amount or a prediction of the drain water amount of the at least a part of the plurality of indoor units.

3. The air conditioning system of claim 2,

the determination unit performs the determination based on the drain water amount or the prediction of the drain water amount of the at least a part of the plurality of indoor units, and a power supply capacity of the power supply unit.

4. Air conditioning system according to any of claims 1 to 3,

the controller causes at least the compressor to perform an oil return operation or a defrosting operation in the refrigerant cycle,

the determination unit determines whether or not to continue the oil return operation or the defrosting operation when the power supply unit supplies the auxiliary power to the at least one portion.

5. The air conditioning system of claim 4,

when the controller executes the oil-return operation in the refrigerant cycle, the controller stops the compressor when the determination unit determines that the oil-return operation is not to be continued.

6. The air conditioning system of claim 5,

the controller stops the compressor according to a degree of humidification of refrigerant drawn by the compressor.

7. The air conditioning system of claim 4,

a plurality of the indoor units respectively include an expansion valve (32),

the controller divides the plurality of indoor units into at least two groups (G1, G2),

when the controller executes the oil-return operation in the refrigerant cycle, and the determination unit determines that the oil-return operation is to be continued, the controller sequentially executes:

a first group closing control in which the expansion valves of the indoor units belonging to a first group (G1) are closed and the expansion valves of the indoor units belonging to a second group (G2) are opened; and

a second group of closing controls in which the expansion valve of the indoor unit belonging to the first group is opened and the expansion valve of the indoor unit belonging to the second group is closed.

8. Air conditioning system according to any of claims 4 to 7,

the outdoor unit further comprises a four-way reversing valve (12),

when the controller executes the defrosting operation in the refrigerant cycle, the controller stops the compressor when the determination unit determines that the defrosting operation is not to be continued.

9. The air conditioning system of claim 7,

the outdoor unit further comprises a four-way reversing valve (12),

when the controller performs the defrosting operation in the refrigerant cycle, the controller switches the four-way selector valve when the determination unit determines that the defrosting operation is to be continued.

10. The air conditioning system of claim 9,

when the controller switches the four-way reversing valve, at least one of the expansion valves is opened, and the compressor operates.