Refrigeration Cycle Equipment

Abstract

A refrigeration cycle device according to one embodiment comprises: a shutoff valve that is disposed in piping for connecting an indoor unit and an outdoor unit and circulating a refrigerant, and opens / closes by means of power from an alternating-current power source; a backup power source capable of alternatively supplying power for driving the shutoff valve during a power interruption of the alternating-current power source; an open / close switch disposed in a power supply path from the backup power source to the shutoff valve; a control circuit that controls the shutoff valve and the open / close switch; and a power interruption detection unit that detects a power interruption of the alternating-current power source. After closing the open / close switch when a power interruption is detected to close the shutoff valve, the control circuit opens the open / close switch.

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a refrigeration cycle device used in an air conditioner or the like. [Background technology]

[0002] In recent years, the use of low-GWP refrigerants, which have a low global warming potential (GWP), has been increasing as refrigerants for air conditioners. However, low-GWP refrigerants are generally flammable, including those with mild flammability. Therefore, safety must be ensured in the event of a refrigerant leak. For refrigeration cycle systems using such flammable refrigerants, such as A2L refrigerants like R32, IEC 60335 requires the installation of a shutoff valve or ventilation fan to stop refrigerant leakage when a refrigerant leak detection device is installed for safety purposes. Furthermore, for shutoff valves installed upstream of the leak location in the refrigeration cycle path, the shutoff valve must be closed to minimize the amount of refrigerant leakage even if a leak occurs during a power outage. Because such safety devices cannot detect refrigerant leaks during a power outage, Patent Documents 1 and 2, for example, describe a backup power supply that is installed in the refrigeration cycle system as a standby power source and that closes the shutoff valve during a power outage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2018 / 078729 issue [Patent Document 2] Japanese Patent Publication No. 2020-134005 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] Backup power sources such as batteries cannot supply power inexhaustibly, and so they must normally be kept in a state where they consume as little power as possible so that they can close the shutoff valve when a refrigerant leaks. Therefore, a refrigeration cycle device capable of suppressing consumption of a backup power source is provided. [Means for solving the problem]

[0005] The refrigeration cycle device of the embodiment includes a shutoff valve that is disposed in a pipe that connects an indoor unit and an outdoor unit that constitute a refrigeration cycle and through which a refrigerant flows, and that is opened and closed by power from an AC power source; a backup power supply capable of supplying power for driving the shutoff valve in place of the AC power supply in the event of a power outage of the AC power supply; an open / close switch disposed in a power supply path from the backup power supply to the shutoff valve; a control circuit for controlling the shutoff valve and the on-off switch; a power outage detection unit that detects a power outage of the AC power supply, When the power outage is detected, the control circuit closes the on-off switch to close the shutoff valve, and then opens the on-off switch. tree, When the power outage is detected and the operation of closing the open / close switch and closing the shutoff valve is performed, it is determined whether the backup power supply has deteriorated. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing the configuration of a refrigeration cycle system in the first embodiment. [Figure 2] FIG. 2 is a functional block diagram showing a detailed configuration of the shutoff valve control device. [Figure 3] FIG. 3 is a functional block diagram showing the configuration shown in FIG. 2 divided into two circuit boards. [Figure 4] FIG. 4 is a flowchart showing the processing contents in the control circuit. [Figure 5]FIG. 5 is a diagram showing an example of changes in cell voltage and battery capacity when charging and discharging are repeated up to 500 cycles at a predetermined temperature for one unit cell constituting a backup power supply in the second embodiment. [Figure 6] FIG. 6 is a flowchart showing the processing contents in the control circuit. [Figure 7] FIG. 7 is a flowchart showing the processing contents in the control circuit in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] (First embodiment) As shown in Fig. 1, the refrigeration cycle device of this embodiment is, for example, an air conditioner comprising an indoor unit 1 installed indoors, an outdoor unit 2 installed outdoors, and refrigerant piping 10, 11 connecting these. This air conditioner further comprises a shutoff valve device 3 and a refrigerant detection alarm 4 interposed midway along the refrigerant piping 10, 11. The indoor unit 1 has an indoor control circuit 5, a fan 6, a heat exchanger 7, and an expansion valve 8 which also serves as a flow control valve, and the indoor control circuit 5 controls the fan 6 which ventilates the indoor heat exchanger and the expansion valve 8 which switches the flow of refrigerant.

[0008] A commercial single-phase or three-phase AC power supply 18 is connected to the indoor unit 1, and this power supply operates the indoor control circuit 5, fan 6, and expansion valve 8. The indoor control circuit 5 also communicates with an outdoor control circuit (not shown) of the outdoor unit 2 via a communication line 9. The shutoff valve device 3, which will be described in detail later, is equipped therein with shutoff valves 12 and 13 for isolating the indoor unit 1 from the refrigeration cycle path. The shutoff valve device 3 can be incorporated into the indoor unit 1, but doing so would increase the size of the indoor unit 1. For this reason, it is desirable to construct the shutoff valve device 3 as a separate box and install it in the attic or under the floor near the indoor unit 1.

[0009] The heat exchanger 7 of the indoor unit 1 is connected to the outdoor unit 2 via a liquid-side pipe 10 and a gas-side pipe 11. A refrigeration cycle is formed by the refrigerant flowing through these pipes. The expansion valve 8 of the indoor unit 1 is located on the liquid-side pipe 10 and is, for example, a pulse motor valve (PMV), whose opening is adjustable from fully closed to fully open. The opening of this expansion valve 8 is controlled by an indoor control circuit 5, which adjusts the pressure and flow rate of the refrigerant flowing to the indoor unit 1. A shutoff valve device 3 is also interposed between the pipes 10 and 11 between the indoor unit 1 and the outdoor unit 2. In this example, the shutoff valve device 3 is a box-shaped body installed in the ceiling or the like. During cooling operation of the indoor unit 1, liquid refrigerant, for example, R32, is sent from the indoor unit 1 through the pipe 10 to the outdoor unit 2. The refrigerant exchanges heat with the indoor air in the heat exchanger 7. In other words, the refrigerant evaporates and becomes gas, and then returns to the outdoor unit 2 through the pipe 11. On the other hand, when the indoor unit 1 is in heating operation, the gas refrigerant compressed to high pressure by the compressor in the outdoor unit 2 flows into the indoor unit 1 through the pipe 11, and exchanges heat with the indoor air in the heat exchanger 7; in other words, the low-pressure refrigerant condenses and becomes liquid, and returns to the outdoor unit 2 through the pipe 11.

[0010] In the air conditioning system of this embodiment, all indoor units in operation operate in the same operation mode. That is, all indoor units in operation can only select either cooling mode or heating mode. In contrast, there are so-called multi-type air conditioners that simultaneously cool and heat, in which multiple indoor units 1 are connected in parallel to the refrigerant piping of a single outdoor unit 2, and the combination of heating and cooling for each indoor unit 1 can be freely selected. When applying to such a simultaneous cooling and heating multi-air conditioner, the indoor units 1 and the outdoor unit 3 are connected by three pipes, so in addition to shut-off valves 12 and 13, a shut-off valve must also be installed in the third pipe.

[0011] The shutoff valve device 3 comprises shutoff valves 12 and 13 disposed in the pipes 10 and 11, respectively, an open / close indicator lamp 14, a control circuit 15 for controlling these, and a backup power supply 16. The control circuit 15 of the shutoff valve device 3 is connected to the indoor control circuit 5 of the indoor unit 1 via a communication bus 17, and communication takes place between the two. The backup power supply 16 is composed of a secondary battery such as a nickel-metal hydride battery. The backup power supply 16 is constantly charged by an AC power supply 18 connected to the shutoff valve device 3, and is used to operate the shutoff valve device 3 in the event of a power outage in the AC power supply 18. The on / off state of the open / close indicator lamp 14 is controlled according to the open / close state of the shutoff valves 12 and 13.

[0012] The shutoff valves 12 and 13 are electronically controlled valves that are motor-driven to control the opening and closing of the valves, such as pulse motor valves that can be fully closed. A similar electronically controlled valve can also be used for the expansion valve 8.

[0013] The refrigerant detection alarm 4, which corresponds to the refrigerant leak detector, has two functions: a refrigerant detection function that detects refrigerant leaks from the indoor unit 1, and an alarm function that issues an alarm when a leak is detected. Furthermore, the refrigerant detection alarm 4 is equipped with a gas sensor 19 that detects a predetermined concentration of refrigerant in the air, an alarm lamp 20, an alarm buzzer 21, a detection status reset switch 22, and a control circuit (not shown) for communicating with the indoor unit 1. FIG. 1 shows an example in which the communication path of the refrigerant detection alarm 4 is directly connected to a communication bus 17 between the control circuit 15 of the shutoff valve device 3 and the indoor control circuit 5 of the indoor unit 1. Alternatively, the refrigerant detection alarm 4 and the indoor control circuit 5 of the indoor unit 1 may be directly connected by a separate communication path, and the output content from the refrigerant detection alarm 4 may be received via that communication path and then provided to the control circuit 15 of the shutoff valve device 3 from the indoor control circuit 5 of the indoor unit 1 via the communication bus 17. When the control circuit 15 of the shutoff valve device 3 receives a refrigerant leakage signal from the refrigerant detection alarm 4, it operates a valve drive circuit 24 shown in Fig. 3 (described later) to fully close the shutoff valves 12 and 13. This prevents the refrigerant sealed in the refrigeration cycle from flowing further into the leaking indoor unit 1, thereby reducing the amount of refrigerant leakage.

[0014] When the gas sensor 19 detects refrigerant gas leaking from the pipes 10, 11 or the indoor unit 1, it outputs a leak detection signal. This lights up the alarm lamp 20 and sounds the alarm buzzer 21. The leak detection signal is then output via the communication bus 17 to the indoor control circuit 5 of the indoor unit 1 and the control circuit 15 of the shut-off valve device 3. The communication bus 17 also serves as a low-voltage DC power line, and the refrigerant detection alarm 4 receives operating power from the indoor unit 1 via the communication bus 17. The refrigerant detection alarm 4 is generally installed in the air-conditioned room where the indoor unit 1 is installed. Since the refrigerant detection alarm 4 is compact, it may be installed inside the indoor unit 1.

[0015] Once the refrigerant detection alarm 4 detects gas, it continues to light the alarm lamp 20, sound the alarm buzzer 21, and send out a leak detection signal, even if the gas concentration drops. A detection state cancel switch 22 is provided to reset this state and return it to the initial state. When a user or repairman operates the detection state cancel switch 22, the alarm lamp 20 goes out, the alarm buzzer 21 stops sounding, and the sending of the leak detection signal stops, and the refrigerant leak detection operation begins again.

[0016] 2 is a functional block diagram showing a detailed configuration of the shutoff valve device 3. The control circuit 15, which corresponds to a control unit, is composed of, for example, an MCU (Micro Control Unit) and its peripheral circuits. The power supply circuit 23 is an AC-DC converter powered by a commercial power supply 18, which is a 100V or 200V single-phase AC power supply, and generates, for example, a 12V DC power supply from the input AC power supply 18 and supplies it to the valve drive circuit 24, the charging circuit 25, etc. The power supply circuit 23 further includes a three-terminal regulator (not shown), which steps down the 12V DC power supply to generate a 5V DC output and supplies it to the control circuit 15.

[0017] Valve drive circuit 24 outputs drive signals for opening and closing shutoff valves 12 and 13, i.e., motor drive signals for opening and closing the valves, in response to control signals from control circuit 15. Charging circuit 25 detects the battery voltage of backup power supply 16, and when that voltage drops to a value that requires charging, it activates and generates an appropriate current from the 12V DC power supply from power supply circuit 23 to charge backup power supply 16. In this way, charging of the battery of backup power supply 16 is carried out under constant current control. When charging of backup power supply 16 is complete, charging circuit 25 terminates its operation and stops constant current output.

[0018] The power failure detection circuit 26, which corresponds to the power failure detection section, has, for example, a photocoupler, the input side of which is connected to the AC power supply 18, and the output side of which is connected to the control circuit 15. As long as the AC power supply 18 continues to supply power, an output signal from the power failure detection circuit 26 is continuously input to the control circuit 15. When a power failure occurs in the AC power supply 18, the input of the output signal to the control circuit 15 is stopped, which becomes a power failure detection signal and is input to the control circuit 15 as an interrupt signal. Here, the power supply 18 for the indoor unit 1 and the power supply 18 for the shutoff valve device 3 may be the same commercial AC power supply, or they may be separate power supplies. If separate power supplies are installed for each, it is possible that a power failure for the indoor unit 1 and a power failure for the shutoff valve device 3 will occur separately.

[0019] Power is supplied from the backup power supply 16 to the DC 12V line via a changeover switch circuit 27 and a power supply circuit 28, which form an on / off switch of the electrical circuit, and the charging circuit 25 and the changeover switch circuit 27 are controlled by the control circuit 15. That is, when the commercial power supply 18 is normal, power is supplied to the valve drive circuit 24 via a power supply circuit 23, and when there is a power outage of the commercial power supply 18, power is supplied via the power supply circuit 23. The charging circuit 25 is also connected to the same DC 12V line, but the charging circuit 25 charges the backup power supply 16 from the charging circuit 25 only when the commercial power supply 18 is operating normally and power is being supplied to the DC 12V line via the power supply circuit 23, and only if the battery voltage of the backup power supply 16 is low.

[0020] The changeover switch circuit 27, which corresponds to an open / close switch, is configured with, for example, a MOSFET, and is kept open, i.e., in the OFF state, while power is being supplied from the power source 18. When a power outage or the like occurs in the power source 18 and the power supply to the shutoff valve device 3 stops, this is detected by the power outage detection circuit 26, and the control circuit 15 closes the changeover switch circuit 27 to the ON state, and power supply to the control circuit 15 from the backup power source 16 via the power supply circuit 28 begins.

[0021] When the backup power supply 16 is fully charged, its voltage is, for example, approximately 8V. The power supply circuit 28 boosts this voltage to 12V and supplies it to the valve drive circuit 24. Similarly to the power supply circuit 23, the power supply circuit 28 also supplies 5V DC power generated by a three-terminal regulator or the like to the control circuit 15. The 5V DC supplied from the power supply circuit 23 to the control circuit 15 is maintained for a certain period of time even during a power outage due to the residual voltage in capacitor C installed in the power supply path. Therefore, the control circuit 15 continues to operate without stopping until the power supply circuit 28 starts supplying power to the control circuit 15 after a power outage. In other words, the power supply to the control circuit 15 is uninterrupted before and after a power outage. The power supply paths from the power supply circuit 23 and the power supply circuit 28 to the control circuit 15 are indicated by dashed lines in FIG. 2. The open / close indicator lamp 14 is not shown.

[0022] A discharge circuit 29 for diagnosing deterioration of the battery used in the backup power supply 16 is connected between the power supply terminal of the backup power supply 16 and the ground. The discharge circuit 29 is composed of a series circuit of a resistance element and a switch circuit, and the opening and closing of the switch circuit is controlled by the control circuit 15. The resistance value of the resistance element is set to be equal to the current consumption when the shut-off valves 12 and 13 are driven by the valve drive circuit 24. The discharge circuit 29 is used in a third embodiment, which will be described later.

[0023] 2 shows a case where electrical circuits that execute functional blocks other than the backup power supply 16 in the shutoff valve device 3 are mounted on the same board 30. Also, the control circuit 15 is configured to control both the driving of the shutoff valves 12 and 13 and the charging and discharging of the backup power supply 16.

[0024] In contrast, the functional block diagram of the shutoff valve device 31 shown in Figure 3 shows a case in which the circuit portion that drives the shutoff valves 12 and 13 and the circuit portion that controls the charging and discharging of the backup power supply 16 are separated and mounted on two boards 30A and 30B. Accordingly, the function of the control circuit 15 is also separated into a portion that drives the shutoff valves 12 and 13 and a portion that controls the charging and discharging of the backup power supply 16, and these are shown as control circuits 15A and 15B, respectively. The control circuit 15A corresponds to the shutoff valve control circuit, and the control circuit 15B corresponds to the switch control circuit. That is, the control circuit 15 in Figure 2 is divided into two: the shutoff valve control circuit that controls the shutoff valves 12 and 13 as control circuit 15A, and the switch control circuit that controls the on-off switch 27 as control circuit 15B.

[0025] The control circuits 15A and 15B each have an MCU for communication with each other, and transmit information about a power outage detected by the control circuit 15A to the control circuit 15B. In the figure, the power supply paths from the power supply circuit 23 and the power supply circuit 28 to the control circuits 15A and 15B are shown by dashed dotted lines, and even with this circuit configuration, the power supply to the control circuits 15A and 15B is not interrupted before or after a power outage. This circuit configuration is suitable when the backup power supply 16 and its peripheral circuits are configured as a backup power supply unit separate from the shutoff valve device 3.

[0026] When the backup power supply 16 side, i.e., the board 30B equipped with the backup power supply 16 and the changeover switch circuit 27, etc., is configured as a backup power supply unit consisting of a single box body and separated from the shutoff valve device 3, the shutoff valve device 3 becomes a shutoff valve device equipped only with the shutoff valves 12 and 13 and the board 30A, i.e., a shutoff valve unit. With this separate configuration, when the backup power supply 16 is not required, the above-mentioned shutoff valve unit alone can be used as a shutoff valve device that shuts off the refrigerant circuit only when the AC power supply 18 is energized and a refrigerant leak is detected, thereby increasing versatility.

[0027] When the shutoff valve unit and the backup power supply unit are separate, the electrical wiring between board A and board B in Fig. 3 is connected by a connector or the like between the backup power supply unit and the shutoff valve device 3. This makes it possible to receive power from the AC power supply 18 via the power supply circuit 23 of the shutoff valve device 3 as shown in Fig. 3. Furthermore, if a power supply circuit the same as the power supply circuit 23 is provided on the backup power supply unit side, it is also possible to connect the backup power supply unit directly to the AC power supply 18.

[0028] In addition, in the configuration of FIG. 2 described above, the portion surrounded by the two-dot chain line can be configured as the backup power supply unit 40, and the remaining components as the shutoff valve unit. In this case, as shown in FIG. 2, the shutoff valve unit is composed of a power supply circuit 23, a power outage detection device 26, a control circuit (MCU) 15, a valve drive circuit 24, and shutoff valves 12 and 13. Meanwhile, the backup power supply unit 40 is composed of a power supply circuit 28, a charging circuit 25, a selector switch circuit 27, a discharge circuit 29, and a backup power supply 16. In this case, seven wires are required between the shutoff valve unit and the backup power supply unit 40. This requires more wires than the four wires required when the shutoff valve unit is divided into boards A and B as shown in FIG. 3 and each board is housed separately in the shutoff valve unit and the backup power supply unit 40. To reduce the number of wires, the configuration with boards A and B as shown in FIG. 3 is preferable. In either case, the backup power supply unit 40 is configured as an electrical parts box that houses a battery, which is the backup power supply 16, and this is installed in the vicinity of the shut-off valve unit in the box body as needed, and wiring between the two is connected using a connector or the like to form the shut-off valve device 3, 31.

[0029] Next, the operation of this embodiment will be described with reference to FIG. 4. FIG. 4 shows control when a power outage occurs. When the AC power supply 18 is turned on to each device and the devices start up, the control circuit 15 initializes itself (S1). At this time, the shutoff valves 12 and 13 are opened, and the selector switch circuit 27 is set to OFF. The device then waits until a power outage occurs in the AC power supply 18 (S2). Here, the shutoff valves 12 and 13 are open when the shutoff valve devices 3, 31 are shipped from the factory. However, if the shutoff valves 12 and 13 are closed due to a power outage during the previous operation, for example, during the initialization in step S1, the control circuit 15 uses power from the power supply circuit 23 to operate the valve drive circuit 24 and control the shutoff valves 12 and 13 to fully open.

[0030] If a power outage occurs in step S2 (Yes), the system transitions to a stopped state (S3), and the control circuit 15 turns on the selector switch circuit 27 (S4). This causes power to be supplied from the backup power supply 16, and the shutoff valves 12 and 13 are closed (S5). When the valve closing operation is complete, the selector switch circuit 27 is turned off (S6), terminating the process. Completion of the valve closing operation can be determined by the valve drive circuit 24 notifying the control circuit 15 that it has completed the valve closing operation, or by measuring the valve closing time required for both the shutoff valves 12 and 13 to go from fully open to fully closed in advance and having the control circuit 15 independently determine that the valve closing time has elapsed since the start of the valve closing operation. Furthermore, completion of the valve closing operation can be determined either by the time the valve drive circuit 24 notifies the control circuit 15 of the completion of the valve closing operation, or by the time elapsed since the valve drive circuit 24 started the valve closing operation until the valve closing time has elapsed, whichever occurs first.

[0031] In step S3 above, the control circuit 5 of the indoor unit 1 and the control circuit of the outdoor unit 2 are notified that a power outage has occurred, and the system is stopped. If the indoor unit 1 and the outdoor unit 2 are connected to the same AC power source 18, each device will experience a power outage in the same way, and the entire air conditioning system will already be stopped when the power outage occurs, but if the indoor unit 1 or the outdoor unit 2 is supplied with power from an AC power source other than the shutoff valve device 3, that device will be able to operate, so the control circuit 15 notifies the control circuit 5 of the indoor unit 1 and the control circuit of the outdoor unit 2 that a power outage has occurred, and stops operation as an air conditioning system.

[0032] When the process shown in FIG. 4 is executed by the shutoff valve device 31 shown in FIG. 3, the process of step S4 is executed by the control circuit 15B while communication is performed between the control circuits 15A and 15B as appropriate, and the other processes are executed by the control circuit 15A.

[0033] As described above, according to this embodiment, the air conditioner is provided with shutoff valves 12, 13 that are arranged in pipes 10, 11 connecting indoor unit 1 and outdoor unit 2 and through which a refrigerant flows, and that are opened and closed by power from AC power supply 18, shutoff valve drive circuit 24, backup power supply 16 that can supply power to shutoff valve drive circuit 24 in place of AC power supply 18 in the event of a power outage, selector switch circuit 27 that is arranged in the power supply path from backup power supply 16 to shutoff valve drive circuit 24, control circuit 15 that controls shutoff valves 12, 13 and selector switch circuit 27, and power outage detection circuit 26 that detects a power outage of AC power supply 18. When a power outage is detected, control circuit 15 closes selector switch circuit 27, which is normally open, to close shutoff valves 12, 13. Then, selector switch circuit 27 is opened.

[0034] In an air conditioner equipped with a backup power supply, without the selector switch circuit 27, the backup power supply and the power supply circuit would be directly connected. Therefore, even if only a small amount, the backup power supply's power is constantly consumed by the power supply circuit and peripheral circuits such as a voltage detection circuit (not shown). The number of times the backup power supply's battery is charged and discharged leads to deterioration. Therefore, in the shutoff valve device 3 of this embodiment, after a power outage occurs and the shutoff valves 12 and 13 are closed, the selector switch circuit 27 is turned OFF to electrically disconnect the backup power supply 16 from the power supply circuit 28. This also stops the control circuit 15, which is composed of an MCU and other components that receive power from the power supply circuit 28, and no signals are generated between the control circuit 15 and the backup power supply 16. Thus, according to this embodiment, unnecessary battery consumption of the backup power supply 16 is minimized, thereby suppressing deterioration of the backup power supply 16.

[0035] 4, the changeover switch circuit 27 is set to OFF by initializing the control circuit 15. As a result, if the AC power supply 18 is in a normal state, power consumption by the power supply circuit 28 and peripheral circuits is prevented, deterioration of the backup power supply 16 is delayed, and its lifespan is extended.

[0036] (Second embodiment) In the following, the same parts as in the first embodiment are given the same reference numerals and their explanations are omitted, and only the differences will be explained. The second embodiment adds a deterioration diagnosis process for the backup power supply 16 to the control of the first embodiment. The backup power supply 16 is made up of multiple nickel-metal hydride battery unit cells connected in series, and the voltage of a unit cell in a fully charged state is around 1.3V.

[0037] Figure 5 shows an example of the changes in cell voltage and battery capacity for one unit cell when 500 cycles are repeated at a predetermined temperature, with one cycle consisting of one unit charge, one hour of rest, one unit discharge, and one hour of rest. After 500 cycles, the battery capacity is 80%, and the battery capacity required to close the shutoff valves 12 and 13 is also 80%. The cell voltage at this time is just over 1.0 V. Therefore, a voltage of 1.0 V is set as the threshold for determining the deterioration of the backup power supply 16.

[0038] Next, the operation of the second embodiment will be described with reference to FIG. 6. The control circuit 15 executes steps S1 to S4, and immediately after turning on the selector switch after a power outage in step S4, determines whether the backup power supply 16 is fully charged (S11). Here, the determination is based on the voltage of the backup power supply 16. For example, if the backup power supply 16 has a six-cell configuration, the voltage in a fully charged state is approximately 1.3V x 6 = 7.8V. Therefore, if the voltage is 7.0V or higher, the backup power supply 16 is determined to be fully charged. If the backup power supply 16 is not fully charged (NO), the situation is inappropriate for degradation diagnosis. Therefore, the degradation diagnosis is terminated at that point (S12), and the shutoff valves 12 and 13 are closed (S132) as in step S5. Then, the selector switch is turned OFF (S6), and the process is terminated (Send). Note that step Send does not actually exist as a control because the power supply to the control circuit 15 itself is stopped by turning off the selector switch, but is represented as a step for convenience of explanation.

[0039] On the other hand, if the backup power supply 16 is fully charged (S11; YES), the valve closing operation is performed (S5), and the voltage of the backup power supply 16 after the valve closing operation is measured (S13). If the measured voltage is 1.0 V or higher (S14; YES), it is determined that the backup power supply 16 has not deteriorated, and the changeover switch circuit 27 is then turned OFF (S6) and the process is terminated (Send). If the measured voltage is less than 1.0 V (NO), it is determined that the backup power supply 16 has deteriorated (S15). The control circuit 15 then stores the deterioration determination status in memory (S16), and then turns OFF the changeover switch circuit 27 (S6) and the process is terminated (Send). If power supply from the AC power supply 18 is resumed after this state, the control circuit 15 performs initialization similar to step S1 (S17), and then, if the deterioration determination status stored in memory indicates deterioration, it outputs an alarm to notify the deterioration of the backup power supply 16. On the other hand, if no degradation information is stored in the memory, the device is in a normal state, and the process proceeds to step S2 without any particular notification.

[0040] When the process shown in FIG. 6 is executed by the shutoff valve device 31 shown in FIG. 3, the processes of steps S1 to S3, S5 and S132 are executed by the control circuit 15A, and the other processes are executed by the control circuit 15B.

[0041] As described above, according to the second embodiment, when a power outage of the AC power supply 18 is detected and the control circuit 15 closes the selector switch circuit 27 to close the shutoff valves 12 and 13, the control circuit 15 determines whether the backup power supply 16 has deteriorated in parallel with the valve closing operation. This allows for efficient deterioration determination.

[0042] (Third embodiment) In the third embodiment, if a power outage of the AC power supply 18 is not detected for a predetermined period of time, a degradation diagnosis process for the backup power supply 16 is forcibly performed using the discharge circuit 29. This degradation diagnosis process is performed while the power supply 18 is energized. As shown in FIG. 7, it is determined (S21) whether a certain time has passed since the previous degradation diagnosis was performed. Here, the certain time is set to, for example, about one month. If the certain time has not passed (NO), the process ends without performing the degradation diagnosis (S22).

[0043] If the predetermined time has elapsed (YES), steps S4 and S11 are executed, and then the switch circuit of the discharge circuit 29 is turned ON (S23), and the backup power supply 16 is forcibly discharged at a current consumption equivalent to that when the shutoff valves 12 and 13 are closed (S24). After that, when the switch circuit of the discharge circuit 29 is turned OFF (S25), steps S13 to S15 are executed as in the second embodiment. Next, in step S18, a notification is issued that the battery of the backup power supply 16 has deteriorated, and this state is stored in memory. Finally, the selector switch is turned OFF, and the deterioration diagnosis process is terminated. The user recognizes the deterioration notification of the backup power supply 16 in step S18, and requests a maintenance or inspection technician to replace the battery of the backup power supply 16, and the maintenance or inspection technician replaces the battery of the backup power supply 16 with a new one.

[0044] As described above, according to the third embodiment, when a period of time during which no power outage of the AC power supply 18 is detected reaches a predetermined length, the control circuit 15 performs a deterioration diagnosis by discharging the backup power supply 16 using the discharge circuit 29. Therefore, the soundness of the backup power supply 16 can be confirmed at least every time a predetermined period of time elapses, and a situation in which the shutoff valves 12, 13 cannot close due to a power shortage in the backup power supply 16 when a power outage occurs can be avoided.

[0045] (Other embodiments) The shutoff valve is not limited to an electronically controlled valve driven by a motor, but may be any valve that can be opened and closed using electricity. The changeover switch circuit is not limited to a MOSFET, but may be a mechanical relay that drives a contact. The cell voltage threshold for deterioration diagnosis is not limited to 1.0V and may be changed as appropriate. The predetermined period between degradation diagnoses is not limited to one month, but frequent forced discharge during degradation diagnoses can itself cause deterioration of the battery of backup power supply 16, so it is desirable that the period be longer than one month. The backup power supply is not limited to a nickel-metal hydride battery, but may also be, for example, a lithium-ion battery.

[0046] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, and combinations of individual structures and processes can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0047] In the drawing, 1 indicates an indoor unit, 2 indicates an outdoor unit, 3 and 31 indicate shut-off valve devices, 4 indicates a refrigerant leak detector alarm (refrigerant leak detector), 10 and 11 indicate refrigerant piping, 15, 15A, and 15B indicate control circuits, 16 indicates a backup power supply, 24 indicates a valve drive circuit, 27 indicates a changeover switch circuit (open / close switch), and 29 indicates a discharge circuit.

Claims

1. a shutoff valve that is disposed in a pipe that connects the indoor unit and the outdoor unit that constitute the refrigeration cycle and through which a refrigerant flows, and that is opened and closed by power from an AC power source; a backup power supply capable of supplying power for driving the shutoff valve in place of the AC power supply in the event of a power outage of the AC power supply; an open / close switch disposed in a power supply path from the backup power supply to the shutoff valve; a control circuit for controlling the shutoff valve and the on-off switch; a power outage detection unit that detects a power outage of the AC power supply, When the power outage is detected, the control circuit closes the on-off switch to close the shutoff valve, and then opens the on-off switch; The refrigeration cycle device determines whether the backup power supply has deteriorated when the power outage is detected and the operation of closing the open / close switch and closing the shutoff valve is performed.

2. A shutoff valve that is disposed in a pipe that connects an indoor unit and an outdoor unit that constitute a refrigeration cycle and through which a refrigerant flows, and that is opened and closed by power from an AC power source; a backup power supply capable of supplying power for driving the shutoff valve in place of the AC power supply in the event of a power outage of the AC power supply; an open / close switch disposed in a power supply path from the backup power supply to the shutoff valve; a control circuit for controlling the shutoff valve and the on-off switch; a power outage detection unit that detects a power outage of the AC power supply; a discharge circuit that discharges the backup power supply, When the power outage is detected, the control circuit closes the on-off switch to close the shutoff valve, and then opens the on-off switch; The open / close switch is kept open while power is being supplied from the AC power source, When the period during which the power outage is not detected reaches a predetermined length, the refrigeration cycle device discharges the backup power supply using the discharge circuit, and determines whether the backup power supply has deteriorated.

3. 3. The refrigeration cycle apparatus according to claim 1, wherein the control circuit outputs an alarm when it determines that the backup power supply has deteriorated.

4. 2. The refrigeration cycle device according to claim 1, wherein the backup power supply is a nickel-metal hydride battery.

5. a refrigerant leakage detection unit that detects refrigerant leakage from the indoor unit; The refrigeration cycle apparatus according to claim 1 , wherein the control circuit closes the shutoff valve when the refrigerant leakage detection unit detects refrigerant leakage from the indoor unit.

6. 2. The refrigeration cycle apparatus according to claim 1, wherein the shutoff valve, the backup power supply, the on-off switch, the control circuit, and the power failure detection unit are integrated as a shutoff valve device and housed in a box.

7. 7. The refrigeration cycle apparatus according to claim 6, wherein a shutoff valve unit including the shutoff valve and a backup power supply unit accommodating the backup power supply and the on-off switch are provided separately.

8. 8. The refrigeration cycle apparatus according to claim 7, wherein the control circuit is housed in the shutoff valve unit.

9. The control circuit is divided into a shutoff valve control circuit that controls the shutoff valve and a switch control circuit that controls the on-off switch, The shutoff valve control circuit is disposed in the shutoff valve unit, and the switch control circuit is disposed in the backup power supply unit, 8. The refrigeration cycle apparatus according to claim 7, wherein the shutoff valve control circuit and the switch control circuit communicate with each other.

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