JP7297160B2 - air conditioner - Google Patents

Description

The present disclosure relates to a multi-type air conditioner to which multiple indoor units can be connected.

Conventionally, multi-type air conditioners are known in which a plurality of indoor units are connected to one outdoor unit. In a multi-type air conditioner, the state of each indoor unit may differ depending on the air conditioning status of the air-conditioned space in which each indoor unit is installed. For example, while the outdoor unit is operating in heating mode, the indoor unit whose room temperature in the air-conditioned space has not reached the set value is in operation, and the indoor unit whose room temperature in the air-conditioned space meets the set value is either thermo-off or Operation may stop when the switch is turned off. Normally, the electronic expansion valve of the stopped indoor unit is closed. In the case of heating operation, in the refrigerant circuit formed by the operating outdoor unit and the stopped indoor unit, only the electronic expansion valve that performs the expansion action is provided on the liquid side of the outdoor heat exchanger. becomes. Therefore, high-pressure gas refrigerant exists in the indoor heat exchanger of the indoor unit that is stopped. Even when the indoor fan is stopped, the high-pressure gas refrigerant causes convective heat transfer with the indoor air in the indoor heat exchanger. It will accumulate in the indoor unit. As a result, the refrigerating cycle formed in the air conditioner becomes short of refrigerant. In order to suppress such a shortage of refrigerant, a generally known method is to slightly open the electronic expansion valve of a stopped indoor unit to allow a small amount of high-pressure gas refrigerant to flow, thereby recovering the condensed liquid refrigerant. .

When the electronic expansion valve of a stopped indoor unit is slightly opened to recover the condensed liquid refrigerant, the heat that should be used for heating operation is radiated by the indoor unit with the thermostat turned off or switched off, resulting in heat loss. Among multiple indoor units, if the number of indoor units that are in heating operation is small compared to the number of indoor units that are inactive, for example, 6 indoor units are inactive and 1 indoor unit is in heating operation. In the case of a stand, heat dissipation loss in the entire multi-type air conditioner is relatively large. Such heat radiation loss can be compensated for by increasing the frequency of a variable capacity compressor whose rotational speed is controlled by an inverter and whose operating capacity is variable, thereby increasing the refrigerant circulation amount. However, efficiency may decrease due to the increased input to the compressor. In Patent Document 1, solenoid valves are provided between the indoor unit and the gas side connection pipe and between the indoor unit and the liquid side connection pipe, respectively, and by controlling the opening and closing of these solenoid valves, A configuration is described that prevents refrigerant from stagnation in a heat exchanger of an indoor unit in which the thermostat is turned off.

JP-A-5-302765

However, in the air conditioner of Patent Literature 1, it is inside the indoor heat exchanger that the accumulation of the refrigerant can be suppressed by controlling the opening and closing of the electromagnetic valve. In the configuration of the air conditioner of Patent Document 1, it is difficult to suppress accumulation of refrigerant generated in the pipe portion between the branch portion and the solenoid valve in the branch pipe that branches from the gas side connection pipe to each indoor unit. is.

The present disclosure has been made against the background of the above problems, and provides an air conditioner that can improve the operation efficiency during heating operation and suppresses the refrigerant from accumulating in the pipes.

An air conditioner according to the present disclosure includes a plurality of indoor units having indoor heat exchangers, an outdoor unit having a compressor and an outdoor heat exchanger, a gas main pipe connected to the outdoor unit, and the outdoor unit. a liquid main pipe connected to the gas main pipe, a plurality of gas branch pipes branched from the gas main pipe and connected to the plurality of indoor units, and a plurality of gas branch pipes branched from the liquid main pipe and connected to the plurality of indoor units a plurality of liquid branch pipes, a plurality of first shield valves provided in the plurality of gas branch pipes, a plurality of second shield valves provided in the plurality of liquid branch pipes, and a plurality of the liquid branches a plurality of expansion valves provided on pipes; and first control means; A refrigerant circuit is formed by one shield valve, the plurality of the second shield valves, and the plurality of expansion valves, and the first control means operates one of the plurality of indoor units during heating operation. is configured to close the first shield valve connected to the indoor unit that is stopped and the second shield valve, and a plurality of the first shield valves connected in parallel and a plurality of second pressure relief valves connected in parallel with the plurality of second shield valves in the plurality of liquid branches.

According to the present disclosure, during heating operation, the first shutoff valve and the second shutoff valve that are connected to the indoor unit that has stopped operating among the plurality of indoor units are closed. Therefore, since the refrigerant is sealed in the pipe connecting the first shield valve, the indoor heat exchanger of the indoor unit whose operation is stopped, and the second shield valve, the liquid refrigerant is prevented from flowing into this pipe. be done. As a result, stagnation of the liquid refrigerant in the pipe and heat radiation loss of the refrigerant are suppressed, and the efficiency of the heating operation is improved.

1 is a system configuration diagram of an air conditioner according to Embodiment 1 of the present disclosure; FIG. 1 is a configuration diagram of a branching device of an air conditioner according to Embodiment 1 of the present disclosure; FIG. 4 is a flowchart showing a processing procedure for transmitting indoor unit information from the indoor unit to the outdoor unit in the air conditioner of the present disclosure; 4 is a flow chart showing a control procedure for the first shield valve and the second shield valve in the air conditioner of the present disclosure; 4 is a flowchart showing a processing procedure for determining whether to open or close a first shield valve and a second shield valve in the air conditioner of the present disclosure; 1 is a system configuration diagram of an air conditioner according to Embodiment 1 of the present disclosure; FIG. FIG. 7 is a configuration diagram of a branching device of an air conditioner according to Embodiment 2 of the present disclosure;

Hereinafter, embodiments of an air conditioner according to the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present disclosure. In addition, the present disclosure includes all combinations of configurations that can be combined among the configurations shown in the following embodiments. In addition, the air conditioners shown in the drawings are examples of devices to which the air conditioners of the present disclosure are applied, and the air conditioners shown in the drawings do not limit the applicable devices of the present disclosure. . Also, in the following description, terms representing directions (for example, "up", "down", "right", "left", "front", "back", etc.) are used as appropriate for ease of understanding. They are intended to be illustrative and not limiting of the present disclosure. Also, in each figure, the same reference numerals denote the same or corresponding parts, which are common throughout the specification. In each drawing, the relative dimensional relationship, shape, etc. of each component may differ from the actual one.

Embodiment 1.
FIG. 1 is a system configuration diagram of an air conditioner according to Embodiment 1 of the present disclosure. The air conditioner 1 includes a branching device 10 , an outdoor unit 20 , multiple indoor units 30 , and multiple remote controllers 60 . The air conditioner 1 is a building multi-type air conditioner in which a plurality of indoor units 30 are connected to an outdoor unit 20 . In Embodiment 1, three indoor units 30 are connected to the outdoor unit 20 via the branching device 10 . In the following description, when referring to each of the plurality of indoor units 30 and the plurality of remote controllers 60, A, B, and C are added to the end of each reference numeral. Also, in the following description, the plurality of indoor units may be collectively referred to as indoor unit 30 and the plurality of remote controllers may be collectively referred to as remote controller 60 .

The outdoor unit 20 has an outdoor heat exchanger 21 , a compressor 22 , a flow path switching section 23 and an outdoor unit control means 24 . The outdoor unit control means 24 corresponds to the second control means of the present disclosure. The compressor 22 is a variable capacity compressor whose rotation speed is controlled by an inverter (not shown) and whose operating capacity is variable. The outdoor heat exchanger 21 exchanges heat between the refrigerant and outside air supplied by an outdoor fan (not shown). The channel switching unit 23 changes the flow of the refrigerant in the refrigerant circuit formed in the air conditioner 1 according to the heating operation and the cooling operation, and is, for example, a four-way valve. In FIG. 1, the flow of the refrigerant during the heating operation is indicated by solid arrows, and the flow of the refrigerant during the cooling operation is indicated by the dotted arrows.

Each of the three indoor units 30 has an indoor heat exchanger 31 and an indoor unit control means 32 . The indoor unit 30 is a type of indoor unit that does not incorporate an electronic expansion valve. The indoor unit 30A has an indoor heat exchanger 31A and an indoor unit control means 32A, the indoor unit 30B has an indoor heat exchanger 31B and an indoor unit control means 32B, and the indoor unit 30C has an indoor heat exchanger 31C. and indoor unit control means 32C. The indoor heat exchanger 31A exchanges heat between the refrigerant and the air supplied by an indoor fan (not shown). The indoor heat exchanger 31B exchanges heat between the refrigerant and the air supplied by an indoor fan (not shown). The indoor heat exchanger 31C exchanges heat between the refrigerant and the air supplied by an indoor fan (not shown).

The branching device 10 is provided between the outdoor unit 20 and the indoor units 30A, 30B, and 30C. The branching device 10 has a plurality of first shield valves 11 , a plurality of second shield valves 12 , a plurality of expansion valves 13 , and branching device control means 100 . The expansion valve 13 is an electronic expansion valve. The branching device control means 100 corresponds to the first control means of the present disclosure. In the following description, when referring to each of the plurality of first shut-off valves 11, A, B, and C are added to the end of each symbol. The same applies to the multiple second shield valves 12 and the multiple expansion valves 13 . Further, in the following description, the plurality of first shield valves are collectively referred to as first shield valves 11, the plurality of second shield valves are collectively referred to as second shield valves, and the plurality of expansion valves 13 are collectively referred to as expansion valves 13. Sometimes. The first shut-off valve 11 , the second shut-off valve 12 and the expansion valve 13 are housed in a single housing 14 .

A gas main pipe 40 and a liquid main pipe 50 are connected to the outdoor unit 20 . The discharge side of the compressor 22 is connected to the flow switching section 23 , and the flow switching section 23 is connected to the gas main pipe 40 . One of the outdoor heat exchangers 21 is connected to the flow path switching section 23 and the other is connected to the liquid main pipe 50 .

In the branching device 10 , a plurality of gas branch pipes 41 branch from the gas main pipe 40 , and a plurality of liquid branch pipes 51 branch from the liquid main pipe 50 . In Embodiment 1, three gas branch pipes 41A, 41B and 41C and three liquid branch pipes 51A, 51B and 51C are branched corresponding to the three indoor units 30A, 30B and 30C. In the following description, when referring to each of the gas branch pipe 41 and the liquid branch pipe 51, A, B, and C are attached to the end of each reference numeral. Further, in the following description, a plurality of gas branch pipes may be collectively referred to as gas branch pipes 41 and a plurality of liquid branch pipes may be collectively referred to as liquid branch pipes 51 .

In the branching device 10, the gas branch pipe 41A is connected to the first shield valve 11A, the gas branch pipe 41B is connected to the first shield valve 11B, and the gas branch pipe 41C is connected to the first shield valve 11C. there is

In the branching device 10, the second shield valve 12A and the expansion valve 13A are connected to the liquid branch pipe 51A. The second shield valve 12A is arranged downstream of the expansion valve 13A in the refrigerant flow during heating operation. A second shield valve 12B and an expansion valve 13B are connected to the liquid branch pipe 51B. The second shield valve 12B is arranged downstream of the expansion valve 13B in the refrigerant flow during heating operation. A second shield valve 12C and an expansion valve 13C are connected to the liquid branch pipe 51C. The second shield valve 12C is arranged downstream of the expansion valve 13C in the refrigerant flow during heating operation.

A gas branch pipe 41A and a liquid branch pipe 51A are connected to the indoor heat exchanger 31A. A gas branch pipe 41B is connected to one end of the indoor heat exchanger 31B, and a liquid branch pipe 51B is connected to the other end. A gas branch pipe 41C is connected to one side of the indoor heat exchanger 31C, and a liquid branch pipe 51C is connected to the other side.

In the air conditioner 1, the compressor 22, the flow path switching unit 23, the first shield valve 11, the indoor heat exchanger 31, the expansion valve 13, the second shield valve 12, the gas main pipe 40, the gas branch pipe 41, the liquid main pipe 50 , and a liquid branch pipe 51 form a refrigerant circuit.

The branching device 10 and the outdoor unit 20 are connected by an outdoor transmission line 70 . Signals are transmitted and received between the branching device control means 100 and the outdoor unit 20 via the outdoor transmission line 70 . The branching device 10 and the indoor units 30A, 30B, and 30C are connected by an indoor transmission line 80. FIG. Signals are transmitted and received between the branching device control means 100 and the indoor units 30A, 30B, and 30C via the indoor transmission line 80 . A remote control 60A is connected to the indoor unit 30A via a remote control line 26A, and signals are transmitted and received between the indoor unit control means 32A and the remote control 60A via the remote control line 26A. A remote control 60B is connected to the indoor unit 30B via a remote control line 26B, and signals are transmitted and received between the indoor unit control means 32B and the remote control 60B via the remote control line 26B. A remote control 60C is connected to the indoor unit 30C via a remote control line 26C, and signals are transmitted and received between the indoor unit control means 32C and the remote control 60C via the remote control line 26C.

During heating operation, the flow path switching unit 23 is switched to the state indicated by the solid line by the outdoor unit control means 24 . During heating operation, when high-temperature and high-pressure gas refrigerant is discharged from the compressor 22 , the gas refrigerant passes through the flow path switching unit 23 and is guided to the branching device 10 via the main gas pipe 40 . The gas refrigerant passes through the first shutoff valve 11 and is led to the indoor unit 30 . At this time, depending on the operating state of the indoor units 30A, 30B, and 30C, the gas refrigerant is branched by the gas branch pipes 41A, 41B, and 41C, and passes through the first shield valves 11A, 11B, and 11C. , to the indoor units 30A, 30B, and 30C. The gas refrigerant introduced to the indoor unit 30 exchanges heat with indoor air in the indoor heat exchanger 31 and is condensed to become a liquid refrigerant. The liquid refrigerant flowing out of the indoor heat exchanger 31 is guided to the expansion valve 13 of the branching device 10 via the liquid branch pipe 51 . The liquid refrigerant is decompressed by the expansion valve 13 and becomes a gas-liquid two-phase state. The refrigerant in the gas-liquid two-phase state passes through the second shield valve 12 and is guided to the outdoor heat exchanger 21 . In the outdoor heat exchanger 21, the refrigerant exchanges heat with the outdoor air and evaporates to become gaseous refrigerant. The gas refrigerant that has flowed out of the outdoor heat exchanger 21 is sucked into the compressor 22 via the flow path switching section 23 .

During cooling operation, the flow path switching unit 23 is switched to the state indicated by the dotted arrow by the outdoor unit control means 24 . During cooling operation, when high-temperature and high-pressure gas refrigerant is discharged from the compressor 22 , the gas refrigerant is led to the outdoor heat exchanger 21 via the flow path switching section 23 . In the outdoor heat exchanger 21, the gas refrigerant exchanges heat with the outdoor air and is condensed into a liquid refrigerant. The liquid refrigerant flowing out of the outdoor heat exchanger 21 is guided to the branching device 10 via the liquid main pipe 50 . The liquid refrigerant passes through the second shield valve 12 , is decompressed by the expansion valve 13 , and is led to the indoor unit 30 via the liquid branch pipe 51 . At this time, the liquid refrigerant is branched by the liquid branch pipes 51A, 51B, and 51C and guided to the indoor units 30A, 30B, and 30C according to the operating states of the indoor units 30A, 30B, and 30C. The refrigerant guided to the indoor unit 30 exchanges heat with indoor air in the indoor heat exchanger 31, evaporates, and becomes a low-pressure gas refrigerant. The low-pressure gas refrigerant flowing out of the indoor heat exchanger 31 passes through the first shield valve 11 of the branching device 10 via the gas branch pipe 41 and is guided to the outdoor unit 20 via the gas main pipe 40 . The low-pressure gas refrigerant guided to the outdoor unit 20 is sucked into the compressor 22 via the flow path switching section 23 .

FIG. 2 is a configuration diagram of the branching device of the air conditioner according to Embodiment 1 of the present disclosure. The branching device 10 has branching device control means 100 . The branch unit control means 100 is composed of dedicated hardware or a CPU (Central Processing Unit) that executes a program stored in a memory. Note that the CPU is also called a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a processor.

If the branching device control means 100 is dedicated hardware, the branching device control means 100 may be, for example, a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or any of these. A combination is applicable. Each of the functional units implemented by the branching device control means 100 may be implemented by individual hardware, or each functional unit may be implemented by one piece of hardware.

When branching device control means 100 is a CPU, each function executed by branching device control means 100 is implemented by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in memory. The CPU implements each function of the branching device control means 100 by reading and executing the programs stored in the memory. Here, the memory is, for example, non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM or EEPROM.

Part of the function of the branching device control means 100 may be realized by dedicated hardware and part may be realized by software or firmware.

Note that the indoor unit control means 32A, the indoor unit control means 32B, the indoor unit control means 32C, and the outdoor control means 33 shown in FIG. It consists of a CPU that executes a program.

Branching device control means 100 according to the first embodiment includes, as functional units, unique address identification means 101, expansion valve control means 102, outdoor unit communication means 103, indoor unit communication means 104, first shield valve It has control means 105 and second shut-off valve control means 106 . The first shut-off valve control means 105 is connected to the first shut-off valves 11A, 11B, and 11C by first shut-off valve control lines 110 . The second shut-off valve control means 106 is connected to the second shut-off valves 12A, 12B, and 12C by second shut-off valve control lines 111 . The expansion valve control means 102 is connected by an expansion valve control line 112 to the expansion valves 13A, 13B and 13C.

Signals are transmitted and received between the outdoor unit communication means 103 and the outdoor unit control means 24 (see FIG. 1) via the outdoor transmission line 70 . Signals are transmitted and received between the indoor unit communication means 104 and the indoor unit control means 32 (see FIG. 1) via the indoor transmission line 80 .

The indoor unit communication means 104 receives indoor unit information output from the indoor unit control means 32 of the indoor unit 30 . That is, indoor unit information output by the indoor unit control means 32A of the indoor unit 30A, indoor unit information output by the indoor unit control means 32B of the indoor unit 30B, and indoor unit information output by the indoor unit control means 32C of the indoor unit 30C is input to the indoor unit communication means 104 . The indoor unit information includes operating information indicating whether the indoor unit 30 is in the thermo-on state or the thermo-off state.

The unique address identification means 101 adds, to the indoor unit information received by the indoor unit communication means 104, the unique address of the indoor unit 30 that has output the indoor unit information. That is, in the unique address identification means 101, the unique address of the indoor unit 30A is added to the indoor unit information output from the indoor unit control means 32A, and the indoor unit information output from the indoor unit control means 32B is added to the indoor unit 30B. is added, and the unique address of the indoor unit 30C is added to the indoor unit information output from the indoor unit control means 32C.

The indoor unit information to which the unique address is added by the unique address identification means 101 is transmitted from the outdoor unit communication means 103 to the outdoor unit control means 24 . The outdoor unit communication means 103 sends a signal instructing opening/closing of the first shield valves 11A, 11B, and 11C, the second shield valves 12A, 12B, and 12C, and the expansion valves 13A, 13B, and 13C to the outdoor unit control unit. Receive from means 24 .

Based on the signal received by the outdoor unit communication means 103 from the outdoor unit control means 24, the first shutoff valve control means 105 sends signals to the first shutoff valves 11A, 11B, and 11C via the first shutoff valve control line 110. Outputs a signal that instructs opening and closing.

Based on the signal received by the outdoor unit communication means 103 from the outdoor unit control means 24, the second shutoff valve control means 106 transmits signals to the second shutoff valves 12A, 12B, and 12C via the second shutoff valve control line 111. Outputs a signal that instructs opening and closing.

The expansion valve control means 102 sends a signal to the expansion valves 13A, 13B, and 13C through the expansion valve control line 112 based on the signal received by the outdoor unit communication means 103 from the outdoor unit control means 24. to output

FIG. 3 is a flowchart showing a processing procedure for transmitting indoor unit information from the indoor unit to the outdoor unit in the air conditioner of the present disclosure. In step S<b>101 , a remote control signal is transmitted from the remote control 60 operated by the user to the indoor unit 30 via the remote control line 26 . The remote control signal includes a command to start or stop the operation of the indoor unit 30 .

In step S<b>102 , the remote control signal is received by the indoor unit control means 32 of the indoor unit 30 . In step S<b>103 , the indoor unit control means 32 transmits the received indoor unit information to the branching device 10 . The indoor unit information includes operating state information and thermo state information. The operating state information is the operating information of the indoor unit corresponding to the command included in the received remote control signal, that is, the information indicating whether the indoor unit 30 is operating or not. "During operation" of the indoor unit 30 means a switch-on state, and "while the indoor unit 30 is stopped" means a switch-off state. The thermo state information is information indicating whether the indoor unit 30 is in the thermo ON state or the thermo OFF state. The thermo-on state is a state in which the temperature of the air-conditioned space of the indoor unit 30 has not reached the set temperature and the indoor unit 30 is operating. The thermo-off state is a state in which the temperature of the air-conditioned space of the indoor unit 30 has reached the set temperature and the indoor unit 30 is not operating.

In step S104, the indoor unit communication means 104 of the branching device control means 100 receives the indoor unit information. In step S105, the unique address identification means 101 of the branching device control means 100 adds the unique address of the indoor unit 30 to the received indoor unit information. In step S 106 , the indoor unit information to which the unique address is added is transmitted from the branching device control means 100 to the outdoor unit 20 via the outdoor unit communication means 103 .

In step S<b>107 , the outdoor unit control means 24 of the outdoor unit 20 receives the indoor unit information output from the branching device control means 100 .

FIG. 4 is a flow chart showing the control procedure of the first shield valve and the second shield valve in the air conditioner of the present disclosure. Step S107 in FIG. 4 is the same processing as step S107 in FIG. is. Next, in step S201, the outdoor unit control means 24 of the outdoor unit 20 executes a subroutine for determining opening/closing of the first shutoff valve 11 and the second shutoff valve 12. FIG.

FIG. 5 is a flowchart showing a processing procedure for determining whether to open or close the first shield valve and the second shield valve in the air conditioner of the present disclosure. 5 shows the control procedure of the subroutine of step S201 in FIG. In step S301, the outdoor unit control means 24 reads the operating state information and thermo state information of the indoor unit 30 from the received indoor unit information.

Next, in step S302, the outdoor unit control means 24 checks whether the indoor unit 30 is in operation based on the operating state information read in step S301. If it is confirmed that the operation of the indoor unit 30 is stopped, the process proceeds to step S303. In step S303, the outdoor unit control means 24 does not need to circulate the refrigerant in the indoor unit 30 that is in the shutdown state, that is, in the switch-off state. A decision is made to close the valve 11 and the second shut-off valve 12 . That is, the outdoor unit control means 24 determines to close the first shield valve 11A and the second shield valve 12A when the indoor unit 30A is out of operation, and when the indoor unit 30B is out of operation, the first shield valve 11B and the second shutoff valve 12B are determined to be closed, and when the indoor unit 30C is out of operation, the first shutoff valve 11C and the second shutoff valve 12C are determined to be closed.

If it is confirmed in step S302 that the indoor unit 30 is in operation, the process proceeds to step S304. In step S304, the outdoor unit control means 24 checks whether the indoor unit 30 confirmed to be in operation in step S302 is in the thermo-on state based on the thermo status information read in step S301. If it is confirmed that the indoor unit 30 is thermo-on, the process proceeds to step S305. The case where the process proceeds to step S305 means that the indoor unit 30 is in operation, the thermostat is on, and the air conditioning process by the indoor unit 30 is in operation. Therefore, the outdoor unit control means 24 determines opening of the first shutoff valve 11 and the second shutoff valve 12 . That is, the outdoor unit control means 24 determines opening of the first shield valve 11A and the second shield valve 12A when the indoor unit 30A is in operation and thermo-on, and when the indoor unit 30B is in operation and thermo-on, the first The opening of the shield valve 11B and the second shield valve 12B is determined, and when the indoor unit 30C is in operation and the thermostat is ON, the opening of the first shield valve 11C and the second shield valve 12C is determined.

On the other hand, if it is confirmed in step S304 that the indoor unit 30 is thermo-off, the process proceeds to step S303. A case where the indoor unit 30 is thermo-off is a case where the indoor unit 30 is in operation but the air conditioning process by the indoor unit 30 is suspended. Therefore, the process proceeds to step S303, and the outdoor unit control means 24 determines closing of the first shutoff valve 11 and the second shutoff valve 12 as described above.

After the process of step S303 or step S305 is executed, the subroutine of FIG. 5 ends, and the process proceeds to step S202 of FIG. In step S<b>202 , the outdoor unit 20 transmits opening/closing signals for the first shield valve 11 and the second shield valve 12 to the branching device control means 100 .

In step S<b>203 , the outdoor unit communication means 103 of the branching device control means 100 receives the open/close signals of the first shield valve 11 and the second shield valve 12 . Next, in step S204, the first shield valve control means 105 controls opening and closing of the first shield valves 11A, 11B, and 11C based on the opening/closing signal of the first shield valve 11 received by the outdoor unit communication means 103. Further, in step S204, based on the open/close signal of the second shutoff valve 12 received by the outdoor unit communication means 103, the second shutoff valve control means 106 controls opening and closing of the second shutoff valves 12A, 12B, and 12C.

As described above, in Embodiment 1, in the air conditioner 1 during heating operation, the first shutoff valve 11 and the second shutoff valve 12 of the indoor unit 30 that has stopped operating among the plurality of indoor units 30 is configured to be closed.

FIG. 6 is a system configuration diagram of an air conditioner according to Embodiment 1 of the present disclosure. FIG. 6 shows a case where the indoor unit 30A is out of operation and the indoor units 30B and 30C are in heating operation. Here, the flow of refrigerant in the air conditioner 1 during heating operation will be described with reference to FIG. 6 . In FIG. 6, the refrigerant flow is indicated by solid arrows, the open first and second shutoff valves 11 and 12 are shown in white, and the closed first and second shutoff valves 11 and 12 are shown in white. 12 is shown in black. Since the indoor units 30 and 30C are heating, the first shutoff valves 11B and 11C and the second shutoff valves 12B and 12C are open. Therefore, the refrigerant flows between the branching device 10, the indoor units 30B and 30C, and the outdoor unit 20, as described above with reference to FIG.

On the other hand, the indoor unit 30A is out of operation, that is, out of operation, so the first shutoff valve 11A and the second shutoff valve 12A are closed. Therefore, heat exchange is not performed in the indoor heat exchanger 31A, heat radiation loss of the refrigerant is suppressed, and hot air and refrigerant noise from the indoor unit 30A are suppressed. Furthermore, in Embodiment 1, the refrigerant is sealed in the pipe connecting the first shield valve 11A, the indoor heat exchanger 31A, and the second shield valve 12A. Therefore, the liquid refrigerant is prevented from flowing not only into the indoor heat exchanger 31A but also into the gas branch pipe 41A and the liquid branch pipe 51A connected to the indoor heat exchanger 31A. As a result, the accumulation of the liquid refrigerant in the gas branch pipe 41A and the liquid branch pipe 51A and the heat radiation loss of the refrigerant are suppressed.

Although three indoor units 30 are connected to one outdoor unit 20 in Embodiment 1, the present invention is not limited to this. A configuration in which two or four or more indoor units 30 are connected to the outdoor unit 20 may be employed.

Furthermore, although the air conditioner 1 of Embodiment 1 is a multi-type air conditioner, an air conditioner having a configuration in which one indoor unit is connected to an outdoor unit may also perform the above-described processing during heating operation. can be processed in the same way as In this case, a gas side cutoff valve is provided on the gas pipe connecting the outdoor unit and the indoor unit, and a liquid side cutoff valve is provided on the liquid pipe connecting the outdoor unit and the indoor unit. Also, an expansion valve is provided in the liquid pipe. When the heating operation is stopped, the gas side cutoff valve and the liquid side cutoff valve are controlled to be closed. This control may be configured to be executed by a control device provided in the outdoor unit, or may be configured to be executed by a control device that controls the entire air conditioner.

Embodiment 2.
FIG. 7 is a configuration diagram of a branching device of an air conditioner according to Embodiment 2 of the present disclosure. In FIG. 7, the same components as those of the air conditioner 1 and the branching device 10 according to Embodiment 1 are denoted by the same reference numerals. In addition to the plurality of first shutoff valves 11 and the plurality of second shutoff valves 12, the branching device 130 includes a plurality of first pressure relief valves 15, a plurality of first check valves 16, and a plurality of second pressure relief valves. It has a valve 17 and a plurality of second check valves 18 . FIG. 7 representatively shows an indoor unit 30A, and a gas branch pipe 41A and a liquid branch pipe 51A connected to the indoor unit 30A. 7 representatively shows the first shield valve 11A, the first pressure relief valve 15A, the first check valve 16A, the second shield valve 12A, the second pressure relief valve 17A, and the second check valve 18A. It is

The first pressure relief valve 15A is connected in parallel with the first shield valve 11A by a first gas branch sub-pipe 42A. The second pressure relief valve 17A is connected in parallel with the second shield valve 12A by a first liquid branch sub-pipe 52A. The first pressure relief valve 15A is configured to be closed when the refrigerant pressure in the pipe connecting the first shield valve 11A, the indoor heat exchanger 31A and the second shield valve 12A is below a specified pressure. Further, the first pressure relief valve 15A is configured to be opened when the refrigerant pressure in the pipe connecting the first shield valve 11A, the indoor heat exchanger 31A and the second shield valve 12A exceeds a specified pressure. . In other words, the first pressure relief valve 15A is closed when the refrigerant pressure inside the first gas branch sub-pipe 42A is equal to or lower than the predetermined pressure, and the refrigerant pressure inside the first gas branch sub-pipe 42A is It is released when the specified pressure is exceeded. In the second embodiment, the specified pressure is set lower than the withstand pressure capability of the parts forming the refrigerant circuit from the first shield valve 11A through the indoor heat exchanger 31A to the second shield valve 12A. there is The second pressure relief valve 17A is configured to be closed when the refrigerant pressure in the piping connecting the first shield valve 11A, the indoor heat exchanger 31A and the second shield valve 12A is below a specified pressure. Further, the second pressure relief valve 17A is configured to be opened when the refrigerant pressure in the pipe connecting the first shield valve 11A, the indoor heat exchanger 31A and the second shield valve 12A exceeds a specified pressure. . In other words, the second pressure relief valve 17A is closed when the refrigerant pressure inside the first liquid branch sub-pipe 52A is below the specified pressure, and the refrigerant pressure inside the first liquid branch sub-pipe 52A exceeds the specified pressure. and is released.

The first check valve 16A is connected in parallel with the first shield valve 11A by a first gas branch sub-pipe 42A. The first check valve 16A is arranged so as to allow the refrigerant to pass only in the direction from the indoor unit 30A to the outdoor unit 20. As shown in FIG. The second check valve 18A is connected in parallel with the second shield valve 12A via the first liquid branch sub-pipe 52A. The second check valve 18A is arranged so as to allow the refrigerant to pass only in the direction from the indoor unit 30A to the outdoor unit 20. As shown in FIG.

The first pressure relief valve 15A and the first check valve 16A are arranged in the first gas branch sub-pipe 42A so that the first check valve 16A is positioned upstream of the first pressure relief valve 15A in the refrigerant flow during heating operation. is provided in The second pressure relief valve 17A and the second check valve 18A are arranged in the first liquid branch sub-pipe 52A so that the second check valve 18A is positioned upstream of the second pressure relief valve 17A in the refrigerant flow during cooling operation. is provided in That is, the first check valve 16A is positioned closer to the outdoor unit 20 than the first pressure relief valve 15A, and the second check valve 18A is positioned closer to the outdoor unit 20 than the second pressure relief valve 17A. are doing.

When the first shield valve 11A and the second shield valve 12A operate, the refrigerant is sealed in the pipe from the first shield valve 11A through the indoor heat exchanger 31A to the second shield valve 12A and inside the indoor heat exchanger 31A. It will be in a stopped state. If the ambient temperature rises in this state, the refrigerant pressure of the sealed refrigerant rises accordingly. When this refrigerant pressure exceeds the specified pressure of the first shield valve 11A and the second shield valve 12A, the first pressure relief valve 15A and the second pressure relief valve 17A are opened. Therefore, the sealed refrigerant passes through the first pressure relief valve 15A and the first check valve 16A, is guided to the gas main pipe 40, and passes through the second pressure relief valve 17A and the second check valve 18A. Then, it is guided to the liquid main pipe 50 .

Due to the operation of the first shield valve 11A and the second shield valve 12A, when the ambient temperature rises in a state where the refrigerant is sealed on the side of the indoor unit 30A, the internal pressure rises, and the pressure resistance of the parts forming the refrigerant circuit The capacity may be exceeded and parts may break or explode. In the second embodiment, the first pressure relief valve 15A is connected in parallel with the first shield valve 11A, the second pressure relief valve 17A is connected in parallel with the second shield valve 12A, and the first pressure relief valve 15A and The second pressure relief valve 17A is configured to open when the refrigerant pressure exceeds a specified pressure. Therefore, before the refrigerant pressure rises and exceeds the withstand pressure capability of the parts forming the refrigerant circuit, the refrigerant flows to the outdoor unit 20 side, so the refrigerant pressure may exceed the withstand pressure capability of the parts forming the refrigerant circuit. Suppressed. As a result, breakage or rupture of the parts forming the refrigerant circuit can be suppressed.

According to the second embodiment, even when the operation of the indoor unit 30A and the outdoor unit 20 is stopped due to a power failure, it is possible to obtain the effect of suppressing breakage or bursting of the parts forming the refrigerant circuit.

Further, in Embodiment 2, the first check valve 16A is positioned closer to the outdoor unit 20 than the first pressure relief valve 15A, and the second check valve 18A is positioned closer to the outdoor unit than the second pressure relief valve 17A. It is located on the side closer to the machine 20 . Therefore, even if leakage of the refrigerant occurs, the refrigerant can be shut off.

The branching device 130 of Embodiment 2 includes a gas branch pipe 41B and a liquid branch pipe 51B connected to the indoor unit 30B, and a gas branch pipe 41C and a liquid branch pipe 51C connected to the indoor unit 30C. , a refrigerant circuit similar to the gas branch pipe 41A and the liquid branch pipe 51A is formed. Therefore, even in the refrigerant circuit to which the indoor unit 30B and the indoor unit 30C are connected, the same effects as those described above can be obtained.

1 air conditioner, 10 branching device, 11 first shield valve, 11A first shield valve, 11B first shield valve, 11C first shield valve, 12 second shield valve, 12A second shield valve, 12B second shield valve , 12C second shield valve, 13 expansion valve, 13A expansion valve, 13B expansion valve, 13C expansion valve, 14 housing, 15 first pressure relief valve, 15A first pressure relief valve, 16 first check valve, 16A second 1 check valve 17 second pressure relief valve 17A second pressure relief valve 18 second check valve 18A second check valve 20 outdoor unit 21 outdoor heat exchanger 22 compressor 23 flow path Switching unit 24 outdoor unit control means 26 remote control line 26A remote control line 26B remote control line 26C remote control line 30 indoor unit 30A indoor unit 30B indoor unit 30C indoor unit 31 indoor heat exchanger 31A indoor heat Exchanger 31B Indoor heat exchanger 31C Indoor heat exchanger 32 Indoor unit control means 32A Indoor unit control means 32B Indoor unit control means 32C Indoor unit control means 33 Outdoor control means 40 Gas main pipe 41 Gas branch pipe, 41A gas branch pipe, 41B gas branch pipe, 41C gas branch pipe, 42A first gas branch sub pipe, 50 liquid main pipe, 51 liquid branch pipe, 51A liquid branch pipe, 51B liquid branch pipe, 51C liquid branch pipe, 52A first liquid branch sub pipe 60 remote controller 60A remote controller 60B remote controller 60C remote controller 70 outdoor transmission line 80 indoor transmission line 100 branching device control means 101 unique address identification means 102 expansion valve control means 103 outdoor machine communication means 104 indoor unit communication means 105 first shield valve control means 106 second shield valve control means 110 first shield valve control line 111 second shield valve control line 112 expansion valve control line 120 housing body, 130 bifurcation device.

Claims (6)

a plurality of indoor units each having an indoor heat exchanger;
an outdoor unit having a compressor and an outdoor heat exchanger;
a gas main pipe connected to the outdoor unit;
a liquid main pipe connected to the outdoor unit;
a plurality of gas branch pipes branched from the gas main pipe and connected to the plurality of indoor units;
a plurality of liquid branch pipes branched from the liquid main pipe and connected to the plurality of indoor units;
a plurality of first shield valves provided in the plurality of gas branch pipes;
a plurality of second shield valves provided in the plurality of liquid branch pipes;
a plurality of expansion valves provided in the plurality of liquid branch pipes;
and a first control means,
The indoor heat exchangers of the plurality of indoor units, the compressors, the outdoor heat exchangers, the plurality of first shield valves, the plurality of second shield valves, and the plurality of expansion valves, A refrigerant circuit is formed at
The first control means closes the first shield valve and the second shield valve that are connected to the indoor unit that has stopped operating among the plurality of indoor units during the heating operation. is composed of
A plurality of first pressure relief valves connected in parallel with the plurality of first shield valves, and a plurality of second pressure relief valves connected in parallel with the plurality of second shield valves in the plurality of liquid branches. An air conditioner having a valve . The outdoor unit has a second control means,
The second control means is configured to determine opening or closing of the plurality of first shield valves and the plurality of second shield valves according to the operating state and thermostat state of each of the plurality of indoor units,
2. The method according to claim 1, wherein the first control means is configured to open or close the plurality of first shield valves and the plurality of second shield valves based on the determination of the second control means. Air conditioner. Each of the plurality of first pressure relief valves and the plurality of second pressure relief valves is defined by a refrigerant pressure in a pipe connecting the first shield valve, the indoor heat exchanger, and the second shield valve. It is closed when the pressure is below the pressure, the first shield valve and the second shield valve are closed, and when the refrigerant pressure in the pipe exceeds the specified pressure, the refrigerant is configured to flow to the outdoor unit. The air conditioner according to claim 1 or 2. a plurality of first check valves connected in parallel with the plurality of first shield valves and allowing the refrigerant to pass only in a direction from the indoor unit to the outdoor unit;
a plurality of second check valves connected in parallel with the plurality of second shield valves and allowing the refrigerant to pass only in a direction from the indoor unit to the outdoor unit;
The first check valve is provided upstream of the first pressure relief valve in the flow of refrigerant in the refrigerant circuit during heating operation,
4. The air conditioner according to claim 3, wherein said second check valve is provided upstream of said second pressure relief valve in the flow of refrigerant in said refrigerant circuit during cooling operation. The plurality of first shield valves, the plurality of second shield valves, and the plurality of expansion valves are housed in a single housing,
The air conditioner according to any one of claims 1 to 4, wherein the housing is provided between the outdoor unit and the plurality of indoor units. 5. The plurality of first pressure relief valves, the plurality of second pressure relief valves, the plurality of first check valves, and the plurality of second check valves are housed in the casing. The air conditioner according to claim 5.

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