Technical Field
[0001] Embodiments of the present invention relate to a refrigeration cycle device used
for an air conditioning device or the like.
Background Art
[0002] In recent years, the use of refrigerants with low global warming potential (GWP),
i.e., so-called low GWP refrigerants, as refrigerants for air conditioning devices
has been increasing. However, in general, low GWP refrigerants are often flammable
refrigerants including mildly flammable refrigerants. For this reason, it is necessary
to ensure safety when a refrigerant has leaked. Refrigeration cycle devices that use
such flammable refrigerants such as A2L refrigerants like R32 must be provided with
a shutoff valve or a ventilation fan for stopping refrigerant leakage when equipment
for detecting refrigerant leakage is installed for the purpose of ensuring safety
in IEC 60335. Furthermore, for the installation of a shutoff valve located upstream
of the refrigeration cycle path in which a leak has occurred, the shutoff valve is
required to be closed in order to minimize the amount of leakage even if refrigerant
leakage has occurred during a power interruption. In such safety devices, since refrigerant
leakage cannot be detected in the event of a power interruption, it is described in,
for example, Patent Literatures 1 and 2 that a backup power source is provided in
a refrigeration cycle device as a standby power source and in the event of a power
interruption, this backup power source is used to close the shutoff valve.
Citation List
Patent Literature
Summary of Invention
Technical Problem
[0004] Since a backup power source such as a battery cannot supply power inexhaustibly,
it must normally be kept in a state where it consumes as little power as possible
in order to close the shutoff valve when the refrigerant has actually leaked.
[0005] Therefore, a refrigeration cycle device capable of reducing consumption of a backup
power source is provided.
Solution to Problem
[0006] A refrigeration cycle device of an embodiment comprises:
a shutoff valve that is disposed in a pipe connecting an indoor unit and an outdoor
unit constituting a refrigeration cycle to circulate a refrigerant and that is opened
and closed by power from an alternating-current power source;
a backup power source capable of alternatively supplying power for driving the shutoff
valve when a power interruption has occurred in the alternating-current power source;
an open and close switch that is 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 and close switch; and
a power interruption detection unit that detects a power interruption in the alternating-current
power source,
wherein when the power interruption has been detected, the control circuit closes
the open and close switch to close the shutoff valve, and then opens the open and
close switch.
Brief Description of Drawings
[0007]
[Figure 1] Figure 1 is a diagram showing the configuration of a refrigeration cycle
system in a first embodiment.
[Figure 2] Figure 2 is a functional block diagram showing the detailed configuration
of a shutoff valve control device.
[Figure 3] Figure 3 is a functional block diagram showing a case where the configuration
shown in Figure 2 is divided into two circuit boards.
[Figure 4] Figure 4 is a flowchart showing processing content in a control circuit.
[Figure 5] Figure 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 source in
a second embodiment.
[Figure 6] Figure 6 is a flowchart showing processing content in a control circuit.
[Figure 7] Figure 7 is a flowchart showing processing content in the control circuit
in the second embodiment.
Description of Embodiments
(First Embodiment)
[0008] As shown in Figure 1, a refrigeration cycle device of this embodiment is, for example,
an air conditioning device including an indoor unit 1 installed indoors, an outdoor
unit 2 installed outdoors, and refrigerant pipes 10, 11 connecting them. This air
conditioning device further includes a shutoff valve device 3 and a refrigerant detection
alarm 4 that are interposed midway along the refrigerant pipes 10, 11. The indoor
unit 1 has an indoor control circuit 5, a fan 6, a heat exchanger 7 and an expansion
valve 8 that also serves as a flow control valve, and the indoor control circuit 5
controls the fan 6 that ventilates the indoor heat exchanger and the expansion valve
8 that changes the flow of the refrigerant.
[0009] A commercial single-phase or three-phase alternating-current power source 18 is connected
to the indoor unit 1, and the indoor control circuit 5, the fan 6, and the expansion
valve 8 operate using this as a power source. Further, the indoor control circuit
5 communicates with an outdoor control circuit (not shown) of the outdoor unit 2 installed
outdoors via a communication line 9. The shutoff valve device 3, which will be described
in detail later, includes therein shutoff valves 12, 13 for isolating the indoor unit
1 from the refrigeration cycle path. The shutoff valve device 3 can be incorporated
within the indoor unit 1, but when it is incorporated, the indoor unit 1 will become
larger in size. For this reason, it is desirable to provide the shutoff valve device
3 as a separate box body and install it above the ceiling or under the floor in the
vicinity of the indoor unit 1.
[0010] The heat exchanger 7 of the indoor unit 1 is connected to the outdoor unit 2 via
a pipe 10 on the liquid side and a pipe 11 on the gas side, and the refrigerant circulates
through these pipes to form the refrigeration cycle. The expansion valve 8 of the
indoor unit 1 is disposed on the pipe 10 side, which is the liquid side, and uses,
for example, a pulse motor valve (PMV) with the opening degree adjustable from full
closure to full open. The opening degree of this expansion valve 8 is controlled by
the indoor control circuit 5 to adjust the pressure and flow rate of the refrigerant
flowing to the indoor unit 1. Further, the shutoff valve device 3 is interposed in
the pipes 10 and 11 between the indoor unit 1 and the outdoor unit 2. Here, the shutoff
valve device 3 is a box body installed above the ceiling, for example. When the indoor
unit 1 is in the cooling operation, the liquid refrigerant such as R32 is sent out
from the outdoor unit 2 to the indoor unit 1 through the pipe 10, and exchanges heat
with the indoor air in the heat exchanger 7, that is, it evaporates to become a gasified
refrigerant, which returns to the outdoor unit 2 through the pipe 11. On the other
hand, when the indoor unit 1 is in the heating operation, the gas refrigerant that
is 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, that is, it is condensed and thus liquefied into a low-pressure
refrigerant, which returns to the outdoor unit 2 through the pipe 11.
[0011] In the air conditioning device in this embodiment, all the indoor units in operation
operate in the same operation mode. That is, all the indoor units in operation can
only select either the cooling operation mode or the heating mode. In contrast, there
are also simultaneous cooling and heating multi-air conditioners that are of a so-called
multi-type in which multiple indoor units 1 are connected in parallel to the refrigerant
pipes of a single outdoor unit 2, and that allow the combination of heating and cooling
for each indoor unit 1 to be freely selected. In the case of application to such simultaneous
cooling and heating multi-air conditioners, the indoor unit 1 and the outdoor unit
2 are connected by three pipes, and therefore a shutoff valve must also be provided
midway along the third pipe in addition to the shutoff valves 12, 13.
[0012] The shutoff valve device 3 includes the shutoff valves 12 and 13 interposed in the
pipes 10 and 11, respectively, an open or close indication lamp 14, a control circuit
15 for controlling them, and a backup power source 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 is carried out between the two.
The backup power source 16 is composed of a secondary battery such as a nickel-metal
hydride battery. The backup power source 16 is normally charged by the alternating-current
power source 18 connected to the shutoff valve device 3, and when a power interruption
has occurred in the alternating-current power source 18, it is used to operate the
shutoff valve device 3. The lit or unlit state of the open or close indication lamp
14 is controlled according to the opened or closed state of the shutoff valves 12
and 13.
[0013] The shutoff valves 12 and 13 are electronically controlled valves that are controlled
to opened and closed by driving a motor, such as pulse motor valves that can be fully
closed. Note that a similar electronically controlled valve can also be used as the
expansion valve 8.
[0014] The refrigerant detection alarm 4, which corresponds to a refrigerant leakage detection
unit, has two functions: a refrigerant detection function to detect leakage of the
refrigerant from the indoor unit 1, and an alarm function to issue an alarm when leakage
has been detected. Furthermore, the refrigerant detection alarm 4 includes a gas sensor
19 that detects a refrigerant at a predetermined concentration in the air, an alarm
lamp 20, an alarm buzzer 21, a detection state cancellation switch 22, and a control
circuit (not shown) for communicating with the indoor unit 1. Figure 1 shows an example
in which the communication path for the refrigerant detection alarm 4 is directly
connected to the 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 via a separate communication path, and the output content
from the refrigerant detection alarm 4 may be received via that communication path
and then provided from the indoor control circuit 5 of the indoor unit 1 to the control
circuit 15 of the shutoff valve device 3 via the communication bus 17. When the control
circuit 15 of the shutoff valve device 3 has received an output indicating refrigerant
leakage from the refrigerant detection alarm 4, it operates a valve drive circuit
24 shown in Figure 3 and described later to fully close the shutoff valves 12, 13.
This prevents the refrigerant filled in the refrigeration cycle from further flowing
into the leaking indoor unit 1, thereby reducing the amount of refrigerant leakage.
[0015] When the refrigerant has leaked from the pipes 10, 11 or the indoor unit 1 and the
gas sensor 19 has detected the refrigerant gas, it outputs a leakage detection signal.
This causes the alarm lamp 20 to light up and the alarm buzzer 21 to sound. Furthermore,
the leakage detection signal is output to the indoor control circuit 5 of the indoor
unit 1 and the control circuit 15 of the shutoff valve device 3 via the communication
bus 17. Note that the communication bus 17 also serves as a low-voltage direct-current
power source line, and the refrigerant detection alarm 4 receives power for operation
from the indoor unit 1 via the communication bus 17. The refrigerant detection alarm
4 is generally installed in an air-conditioned room in which the indoor unit 1 is
installed. Note that since the refrigerant detection alarm 4 is small, the refrigerant
detection alarm 4 may be incorporated inside the indoor unit 1.
[0016] Once detecting gas, the refrigerant detection alarm 4 continues to light the alarm
lamp 20, sound the alarm buzzer 21, and send out the leakage detection signal even
when the concentration of the gas has decreased. In order to reset this state back
to the initial state, the detection state cancellation switch 22 is provided. When
a user or a repair and inspection person operates the detection state cancellation
switch 22, the alarm lamp 20 goes out, the alarm buzzer 21 stops sounding the leakage
detection signal stops being sent out, and the refrigerant leakage detection operation
starts again.
[0017] Figure 2 is a functional block diagram showing the 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.
A power source circuit 23 is an AC-DC converter that uses a commercial single-phase
alternating-current power source 18 at 100 V or 200 V as its power source, generates,
for example, a 12 V direct-current power source from the input alternating-current
power source 18, and supplies it to the valve drive circuit 24, a charging circuit
25, and the like. The power source circuit 23 further includes a three-terminal regulator
(not shown), and uses this to supply the control circuit 15 with a 5 V direct-current
output generated by stepping down the 12 V direct-current power source.
[0018] The valve drive circuit 24 outputs a drive signal for driving the shutoff valves
12 and 13 to open or close, that is, a motor drive signal for opening or closing the
valves in response to a control signal from the control circuit 15. The charging circuit
25 detects the battery voltage of the backup power source 16, and when the voltage
has dropped to a value that requires charging, it starts up, and generates appropriate
current from the 12 V direct-current power source from the power source circuit 23
to charge the backup power source 16. In this manner, the charging of the battery
of the backup power source 16 is carried out under the constant current control. When
the charging of the backup power source 16 has been completed, the charging circuit
25 terminates its operation and stops outputting the constant current.
[0019] The power interruption detection circuit 26, which corresponds to a power interruption
detection unit, has, for example, a photocoupler, with its input side connected to
the alternating-current power source 18 and its output side connected to the control
circuit 15. If the alternating-current power source 18 continues to supply power,
an output signal from the power interruption detection circuit 26 is accordingly input
to the control circuit 15 continuously. When a power interruption has occurred in
the alternating-current power source 18, the input of the above-mentioned output signal
to the control circuit 15 is stopped, and therefore this serves as a power interruption
detection signal, which is input to the control circuit 15 as an interrupt signal.
Here, the power source 18 of the indoor unit 1 and the power source 18 of the shutoff
valve device 3 may be the same commercial alternating-current power source, or may
be separate power sources. When a separate power source is installed for each, a situation
can be assumed in which a power interruption in the indoor unit 1 and a power interruption
in the shutoff valve device 3 occur separately.
[0020] Power supply from the backup power source 16 to the direct-current 12 V line is carried
out via a changeover switch circuit 27 that serves as an open and close switch for
the electric circuit and a power source circuit 28, and the charging circuit 25 and
the changeover switch circuit 27 are controlled by the control circuit 15. That is,
when the commercial power source 18 is normal, power is supplied to the valve drive
circuit 24 via the power source circuit 23, and when a power interruption has occurred
in the commercial power source 18, power is supplied to the valve drive circuit 24
via the power source circuit 28. Although the charging circuit 25 is also connected
to the same direct-current 12 V line, the charging circuit 25 charges the backup power
source 16 from the charging circuit 25 when the battery voltage of the backup power
source 16 has dropped only when the commercial power source 18 is operating normally
and power is being supplied to the direct-current 12 V line via the power source circuit
23.
[0021] The changeover switch circuit 27, which corresponds to an open and close switch,
is composed of, for example, a MOSFET, and is open, that is, set to the OFF state
while power is being supplied from the power source 18. When a power interruption
or the like has occurred in the power source 18 and power supply to the shutoff valve
device 3 has stopped, this is detected by the power interruption detection circuit
26, the changeover switch circuit 27 is closed by the control circuit 15 to enter
the ON state, and power supply to the control circuit 15 from the backup power source
16 via the power source circuit 28 is started.
[0022] When the backup power source 16 is in a fully charged state, the voltage is, for
example, about 8 V, the power source circuit 28 steps it up to 12 V and supplies it
to the valve drive circuit 24, and supplies the control circuit 15 with 5 V direct-current
power generated by a three-terminal regulator or the like, similar to the power source
circuit 23. The 5 V direct-current supplied from the power source circuit 23 to the
control circuit 15 is held for a certain period of time even during a power interruption
due to the residual voltage in a capacitor C provided in the power supply path. Therefore,
the control circuit 15 continues to operate without stopping until power is supplied
from the power source circuit 28 to the control circuit 15 after the occurrence of
the power interruption. That is, the power supply to the control circuit 15 is not
interrupted before and after a power interruption. The power supply paths from the
power source circuit 23 and the power source circuit 28 to the control circuit 15
are indicated by one-dot-dash lines in Figure 2. Note that the illustration of the
open or close indication lamp 14 is omitted.
[0023] A discharging circuit 29 for diagnosing the deterioration of the battery used in
the backup power source 16 is connected between the power supply terminal of the backup
power source 16 and the ground. The discharging 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 are controlled by the control circuit 15. The resistance value
of the resistance element is set to be equivalent to the consumed current when the
shutoff valves 12 and 13 are driven by the valve drive circuit 24. Note that the discharging
circuit 29 is used in a third embodiment described later.
[0024] Here, the functional block diagram shown in Figure 2 shows a case in which the electrical
circuits for executing the functional blocks other than the backup power source 16
in the shutoff valve device 3 are mounted on the same board 30. Further, 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 source 16.
[0025] In contrast, the functional block diagram of the shutoff valve device 31 shown in
Figure 3 shows a case in which the circuit part for driving the shutoff valves 12
and 13 and the circuit part for controlling the charging and discharging of the backup
power source 16 are separated and the electrical circuits forming their respective
functional blocks are mounted separately on two boards 30A, 30B. Following this, the
function of the control circuit 15 is also separated into a part for driving the shutoff
valves 12 and 13 and a part for controlling the charging and discharging of the backup
power source 16, which are shown as control circuits 15A and 15B, respectively. The
control circuit 15A corresponds to a shutoff valve control circuit, and the control
circuit 15B corresponds to a switch control circuit. That is, the control circuit
15 in Figure 2 is divided into two parts: the shutoff valve control circuit that controls
the shutoff valves 12, 13 as the control circuit 15A and the switch control circuit
that controls the open and close switch 27 as the control circuit 15B.
[0026] The control circuits 15A and 15B include their respective MCUs to communicate with
each other, and information about a power interruption detected by the control circuit
15A or the like is transmitted to the control circuit 15B side. In the figure, the
power supply paths from the power source circuit 23 and the power source circuit 28
to the control circuits 15A and 15B are shown by one-dot-dash lines, and even with
this circuit configuration, the power supply to the control circuits 15A and 15B is
not interrupted before and after a power interruption. This circuit configuration
is suitable for the case where the backup power source 16 and its peripheral circuits
are configured as a backup power source unit that is separate from the shutoff valve
device 3.
[0027] When the backup power source 16 side, that is, the board 30B including the backup
power source 16, the changeover switch circuit 27 and the like is separated from the
shutoff valve device 3 as a backup power source unit consisting of a single box body,
the shutoff valve device 3 becomes a shutoff valve device including only the shutoff
valves 12, 13 and the board 30A, that is, a shutoff valve unit. With such a separate
configuration, when the backup power source 16 is not needed, only the above-described
shutoff valve unit can be used as a shutoff valve device for shutting off the refrigerant
circuit only when the alternating-current power source 18 is energized and refrigerant
leakage has been detected, thereby increasing versatility.
[0028] Note that when the shutoff valve unit and the backup power source unit are separate,
the electrical wires between the board A and the board B in Figure 3 are connected
using connectors or the like between the backup power source unit and the shutoff
valve device 3. This makes it possible to receive power from the alternating-current
power source 18 via the power source circuit 23 of the shutoff valve device 3 as shown
in Figure 3. Further, if the same power source circuit as the power source circuit
23 is provided on the backup power source unit side, the backup power source unit
can be directly connected to the alternating-current power source 18.
[0029] Further, in the configuration of Figure 2 described above, the part enclosed by the
two-dot-dash line can be configured as a backup power source unit 40, with the remaining
components being configured as a shutoff valve unit. In this case, as shown in Figure
2, the shutoff valve unit is composed of the power source circuit 23, the power interruption
detection circuit 26, the control circuit (MCU) 15, the valve drive circuit 24, and
the shutoff valves 12, 13. On the other hand, the backup power source unit 40 is composed
of the power source circuit 28, the charging circuit 25, the changeover switch circuit
27, the discharging circuit 29, and the backup power source 16. In this case, seven
wires are required between the shutoff valve unit and the backup power source unit
40. For this reason, the number of wires becomes greater than four in the case where
the board is separated into the board A and the board B in Figure 3, which are separately
housed in the shutoff valve unit and the backup power source unit 40, respectively.
In order to reduce the number of wires, the configuration separated into the board
A and the board B as shown in Figure 3 is more preferable. In either case, the backup
power source unit 40 is configured as an electrical components box that houses a battery
that is the backup power source 16, this is installed in the vicinity of the shutoff
valve unit in a box body as necessary, and then the wires between the two are connected
using connectors or the like to form the shutoff valve devices 3, 31.
[0030] Next, the operation of this embodiment will be described with reference to Figure
4. Figure 4 shows the control in the event of a power interruption. When the alternating-current
power source 18 is applied to each device to start it up, the control circuit 15 executes
initialization of itself (S1). At this time, the shutoff valves 12 and 13 are opened,
and the changeover switch circuit 27 is set to OFF. Then, it waits until a power interruption
occurs in the alternating-current power source 18 (S2). Here, the shutoff valves 12
and 13 are in an open state when the shutoff valve devices 3, 31 are shipped from
the factory, but if they are closed due to a power interruption during the previous
operation or the like, the control circuit 15 operates the valve drive circuit 24
using power from the power source circuit 23 to control the shutoff valves 12 and
13 to be fully open in the initialization in step S1 described above.
[0031] When a power interruption has occurred in step S2 (Yes), the system transitions to
a stopped state (S3), and the control circuit 15 sets the changeover switch circuit
27 to ON (S4). Then, power is supplied from the backup power source 16, and the valve
closing operation of the shutoff valves 12 and 13 is performed (S5). Then, when the
valve closing operation has been completed, the changeover switch circuit 27 is set
to OFF (S6) and the process ends. Regarding the completion of the valve closing operation,
there are a method in which the valve drive circuit 24 notifies the control circuit
15 that the valve closing operation has ended, and a method in which the valve closing
time it takes for both the shutoff valves 12 and 13 to transition from full open to
full closure is measured in advance and the control circuit 15 makes an independent
determination based on the valve closing time having elapsed since the start of the
valve closing operation. Furthermore, the completion of the valve closing operation
may be determined based on the earlier one of the time when the notification of the
end of the valve closing operation from the valve drive circuit 24 has reached the
control circuit 15 and the elapsed time from the start of the valve closing operation
by the valve drive circuit 24 to the elapse of the valve closing time.
[0032] Note that in step S3 described above, the system is stopped by notifying the control
circuit 5 of the indoor unit 1 and the control circuit of the outdoor unit 2 that
a power interruption has occurred. If the indoor unit 1 and the outdoor unit 2 are
connected to the same alternating-current power source 18, each unit experiences a
power interruption in the same way, and therefore the system has already been stopped
as the whole air conditioning device in the event of a power interruption, but when
the indoor unit 1 or the outdoor unit 2 receives power from an alternating-current
power source other than that of the shutoff valve device 3, the unit is still able
to operate, and therefore the control circuit 15 notifies the control circuit 5 of
the indoor unit 1 or the control circuit of the outdoor unit 2 that a power interruption
has occurred, thereby causing it to stop operating as an air conditioning device.
[0033] Note that when the process shown in Figure 4 is executed by the shutoff valve device
31 shown in Figure 3, the process in step S4 is executed by the control circuit 15B
and the other processes are executed by the control circuit 15A while communication
is performed between the control circuits 15A and 15B as appropriate.
[0034] As described above, according to this embodiment, the air conditioning device includes:
the shutoff valves 12, 13 that are disposed in the pipes 10, 11 connecting the indoor
unit 1 and the outdoor unit 2 to circulate the refrigerant and that are opened and
closed by power from the alternating-current power source 18; the shutoff valve drive
circuit 24; the backup power source 16 capable of alternatively supplying power to
the shutoff valve drive circuit 24 when a power interruption has occurred in the alternating-current
power source 18; the changeover switch circuit 27 that is disposed in the power supply
path from the backup power source 16 to the shutoff valve drive circuit 24; the control
circuit 15 that controls the shutoff valves 12, 13 and the changeover switch circuit
27; and the power interruption detection circuit 26 that detects a power interruption
in the alternating-current power source 18. When the power interruption has been detected,
the control circuit 15 closes the changeover switch circuit 27, which is normally
open, to close the shutoff valves 12 and 13. Then, the changeover switch circuit 27
is opened.
[0035] In an air conditioning device including a backup power source, if the changeover
switch circuit 27 is not present, the backup power source and the power source circuit
are directly connected. Therefore, although the amount is small, the power of the
backup power source is always consumed by the power source circuit and peripheral
circuits such as a voltage detection circuit (not shown). The number of times the
battery of the backup power source is charged and discharged is linked to its deterioration.
Therefore, in the shutoff valve device 3 of this embodiment, after a power interruption
occurs and the shutoff valves 12, 13 are closed, the changeover switch circuit 27
is set to OFF to electrically disconnect the backup power source 16 and the power
source circuit 28. As a result, the control circuit 15 composed of the MCU and the
like to which power is supplied from the power source circuit 28 also stops, and signals
are no longer generated between the control circuit 15 and the backup power source
16. As described above, according to this embodiment, unnecessary consumption of the
battery of the backup power source 16 can be reduced as much as possible, and therefore
deterioration of the backup power source 16 can be reduced.
[0036] Furthermore, in this embodiment, the changeover switch circuit 27 is set to OFF by
initialization of the control circuit 15 in step S1 shown in Figure 4. As a result,
if the alternating-current power source 18 is in a normal state, it is possible to
prevent power consumption by the power source circuit 28 or the peripheral circuits
and delay deterioration of the backup power source 16 to extend its lifetime.
(Second Embodiment)
[0037] In the following, the same parts as those in the first embodiment are given the same
reference numerals to omit the description thereof, and the different parts will be
described. The second embodiment is obtained by adding a deterioration diagnosis process
for the backup power source 16 to the control in the first embodiment. The backup
power source 16 is made up of a plurality of nickel-metal hydride battery unit cells
connected in series, and the voltage of a unit cell in a fully charged state is about
1.3 V.
[0038] Figure 5 shows an example of changes in the cell voltage and battery capacity of
one unit cell in a case where one cycle is composed of charging of one unit time,
one hour of rest, discharging of one unit time, and one hour of rest at a predetermined
temperature and is repeated up to 500 cycles. It is assumed that the battery capacity
after the repetitions up to 500 cycles is 80% and the battery capacity required to
close the shutoff valves 12, 13 is also 80%. The cell voltage at that time is just
over 1.0 V. Therefore, a voltage of 1.0 V is set as the threshold for determining
whether the backup power source 16 has deteriorated.
[0039] Next, the operation of the second embodiment will be described with reference to
Figure 6. The control circuit 15 executes steps S1 to S4, and immediately after the
changeover switch is set to ON in step S4 after the occurrence of a power interruption,
it determines whether the backup power source 16 is in a fully charged state (S11).
Here, the determination is made based on the voltage of the backup power source 16.
For example, if the backup power source 16 is composed of six cells, the voltage in
a fully charged state is approximately 1.3 V × 6 = 7.8 V, and therefore when the voltage
is 7.0V or higher, it is determined to be in a fully charged state. If it is not in
a fully charged state (NO), the situation is not suitable for deterioration diagnosis,
the deterioration diagnosis is therefore terminated at that point (S12), the valve
closing operation of the shutoff valves 12, 13 is performed (S132) as in step S5,
and then the changeover switch is set to OFF (S6) to end the process (Send). Note
that since the supply to the power source itself for the control circuit 15 has been
stopped by setting the changeover switch to OFF, step Send does not exist as control,
but it is represented as a step for convenience of explanation.
[0040] On the other hand, if it is in a fully charged state (S11; YES), the valve closing
operation is performed (S5), and the voltage of the backup power source 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 source 16 has not deteriorated,
and then the changeover switch circuit 27 is set to OFF (S6) to end the process (Send).
If the measured voltage is less than 1.0 V (NO), it is determined that the backup
power source 16 has deteriorated (S15). Then, the control circuit 15 stores the deterioration
determination status in a memory (S16), and then sets the changeover switch circuit
27 to OFF (S6) to end the process (Send). Following this state, when the power supply
from the alternating-current power source 18 is resumed, the control circuit 15 performs
initialization (S17) as in step S1, and then, if the deterioration determination status
stored in the memory is deterioration information, outputs an alarm to notify the
deterioration of the backup power source 16. On the other hand, if deterioration information
is not stored in the memory, the state is normal, and therefore the process proceeds
to step S2 without any particular notification.
[0041] Note that when the process shown in Figure 6 is executed by the shutoff valve device
31 shown in Figure 3, the processes in 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.
[0042] As described above, according to the second embodiment, when a power interruption
in the alternating-current power source 18 has been detected and an operation of closing
the changeover switch circuit 27 to close the shutoff valves 12 and 13 is performed,
the control circuit 15 determines whether or not the backup power source 16 has deteriorated
in parallel with the valve closing operation. This makes it possible to efficiently
perform the deterioration determination.
(Third Embodiment)
[0043] In the third embodiment, when a power interruption in the alternating-current power
source 18 has not been detected for a predetermined period of time, the deterioration
diagnosis process for the backup power source 16 is forcibly performed by utilizing
the discharging circuit 29. This deterioration diagnosis process is carried out while
the power source 18 is energized. As shown in Figure 7, it is determined whether the
certain period of time has elapsed since the last deterioration diagnosis (S21). Here,
the certain period of time is set to, for example, about one month. If the certain
period of time has not elapsed (NO), the process ends without carrying out the deterioration
diagnosis (S22).
[0044] If the certain period of time has elapsed (YES), steps S4 and S11 are executed, then
the switch circuit of the discharging circuit 29 is set to ON (S23), and the backup
power source 16 is forcibly discharged at the consumed current equal to that when
the shutoff valves 12 and 13 are closed (S24). Thereafter, when the switch circuit
of the discharging circuit 29 has been set to OFF (S25), steps S13 to S15 are executed
as in the second embodiment. Next, in step S18, a notification that the battery of
the backup power source 16 has deteriorated is issued, and its state is stored in
memory. Finally, the changeover switch is set to OFF to end the deterioration diagnosis
process. The user recognizes the notification of deterioration of the backup power
source 16 in step S18, and requests a maintenance and inspection worker to replace
the battery of the backup power source 16, and the maintenance and inspection worker
replaces the battery of the backup power source 16 with a new one.
[0045] As described above, according to the third embodiment, when a period of time during
which no power interruption in the alternating-current power source 18 is detected
has reached a predetermined length, the control circuit 15 performs deterioration
diagnosis by causing the discharging circuit 29 to discharge the backup power source
16, and therefore it is possible to confirm the soundness of the backup power source
16 at least every time the predetermined period of time elapses, and it is possible
to avoid a situation in which the valve closing operation of the shutoff valves 12,
13 cannot be performed due to a power shortage of the backup power source 16 in the
event of a power interruption.
(Other Embodiments)
[0046] The shutoff valves are not limited to electronically controlled valves driven by
a motor, but may be any valves that can be opened and closed using electricity.
[0047] The changeover switch circuit is not limited to a MOSFET, but may be a mechanical
relay that drives a contact.
[0048] The cell voltage threshold for deterioration diagnosis is not limited to 1.0 V but
may be changed as appropriate.
[0049] Although the predetermined period of time that is an interval of deterioration diagnosis
is not limited to one month, it is desirably a long period of time of one month or
more because frequently performing the forced discharge that is executed during deterioration
diagnosis can itself cause deterioration of the battery of the backup power source
16.
[0050] The backup power source is not limited to a nickel-metal hydride battery, but may
be of another type, for example, a lithium-ion battery.
[0051] Although some 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 recombinations of individual components or processes
can be made without departing from the spirit of the invention. These embodiments
and their variations are included in the scope and spirit of the invention, and are
included in the scope of the invention described in the claims and its equivalents.
Reference Signs List
[0052] In the drawings, 1 indicates the indoor unit, 2 indicates the outdoor unit, 3 and
31 indicate the shutoff valve devices, 4 indicates the refrigerant detection alarm
(the refrigerant leakage detection unit), 10 and 11 indicate the refrigerant pipes,
15, 15A, and 15B indicate the control circuits, 16 indicates the backup power source,
24 indicates the valve drive circuit, 27 indicates the changeover switch circuit (the
open and close switch), and 29 indicates the discharging circuit.
1. Arefrigeration cycle device comprising:
a shutoff valve that is disposed in a pipe connecting an indoor unit and an outdoor
unit constituting a refrigeration cycle to circulate a refrigerant and that is opened
and closed by power from an alternating-current power source;
a backup power source capable of alternatively supplying power for driving the shutoff
valve when a power interruption has occurred in the alternating-current power source;
an open and close switch that is 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 and close switch; and
a power interruption detection unit that detects a power interruption in the alternating-current
power source,
wherein when the power interruption has been detected, the control circuit closes
the open and close switch to close the shutoff valve, and then opens the open and
close switch.
2. The refrigeration cycle device according to claim 1, wherein when the power interruption
has been detected and an operation of closing the open and close switch to close the
shutoff valve is performed, the control circuit determines whether or not the backup
power source has deteriorated.
3. The refrigeration cycle device according to claim 1, wherein the control circuit keeps
the open and close switch open while power is being supplied from the alternating-current
power source.
4. The refrigeration cycle device according to claim 3, comprising a discharging circuit
that discharges the backup power source,
wherein when a period of time during which the power interruption is not detected
has reached a predetermined length, the control circuit causes the discharging circuit
to discharge the backup power source to determine whether or not the backup power
source has deteriorated.
5. The refrigeration cycle device according to claim 2 or 4, wherein the control circuit
outputs an alarm when it is determined that the backup power source has deteriorated.
6. The refrigeration cycle device according to claim 1, wherein the backup power source
is a nickel-metal hydride battery.
7. The refrigeration cycle device according to claim 1, comprising a refrigerant leakage
detection unit that detects refrigerant leakage from the indoor unit,
wherein the control circuit closes the shutoff valve when the refrigerant leakage
detection unit detects refrigerant leakage from the indoor unit.
8. The refrigeration cycle device according to claim 1, wherein the shutoff valve, the
backup power source, the open and close switch, the control circuit, and the power
interruption detection unit are integrated into a shutoff valve device and housed
in a box body.
9. The refrigeration cycle device according to claim 7, wherein a shutoff valve unit
comprising the shutoff valve and a backup power source unit housing the backup power
source and the open and close switch are separate.
10. The refrigeration cycle device according to claim 9, wherein the control circuit is
housed in the shutoff valve unit.
11. The refrigeration cycle device according to claim 9, wherein
the control circuit is divided into two parts: a shutoff valve control circuit that
controls the shutoff valve and a switch control circuit that controls the open and
close switch,
the shutoff valve control circuit is disposed in the shutoff valve unit, and the switch
control circuit is disposed in the backup power source unit, and
the shutoff valve control circuit and the switch control circuit communicate with
each other.