JP7457966B2 - air conditioner - Google Patents

Description

The present invention relates to an air conditioner.

BACKGROUND ART Conventionally, in an air conditioner, a configuration is known in which a refrigerant pipe is provided with an opening/closing device to suppress the amount of refrigerant leakage when refrigerant leakage occurs (for example, see Patent Document 1). In Patent Document 1, during cooling operation, the throttle device of the outdoor unit is controlled to bring the refrigerant flowing through the liquid side piping into a gas-liquid two-phase state, and when leakage of the refrigerant is detected, the upstream side of the indoor heat exchanger is opened and closed. The device and the downstream switching device are kept in a closed state to further reduce the amount of refrigerant leakage.

International Publication No. 2017/203606

However, in conventional air conditioners, the opening/closing device is not closed unless refrigerant leakage occurs. For this reason, there is a risk that sticking may occur due to the opening/closing device not being in the closed state for a long period of time. If the opening/closing device becomes stuck, the opening/closing device cannot be closed in the event of refrigerant leakage, and there is a possibility that the amount of refrigerant leaking from the indoor unit will increase.
The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to suppress the sticking of the opening/closing device in an air conditioner and to suppress the amount of refrigerant leaking from the indoor unit.

In order to solve the above problems, the present invention provides an outdoor unit having a compressor, an indoor unit having a user-side heat exchanger, a refrigerant pipe connecting the outdoor unit and the indoor unit, and a refrigerant pipe disposed in the refrigerant pipe. In the air conditioning apparatus, the control unit executes a sticking prevention operation in which the switchgear is opened and closed when there is no refrigerant leakage; The present invention is characterized in that after a predetermined period of time has elapsed since the closing control of the opening/closing device is performed, abnormality determination control for determining an abnormal state of the opening/closing device is executed .
According to this, since the opening/closing device is opened and closed even when the refrigerant is not leaking, it is possible to suppress the sticking of the opening/closing device.

According to the present invention, it is possible to suppress the sticking of the opening/closing device, so that when refrigerant leakage occurs, the opening/closing device can be easily operated appropriately, and the amount of refrigerant leaking from the indoor unit can be effectively suppressed.

A diagram showing the configuration of an air conditioner according to the first embodiment Block diagram of a control unit of an air conditioning apparatus according to a first embodiment. Flowchart showing the transition determination operation for preventing sticking of the air conditioner according to the first embodiment Flowchart showing the sticking prevention operation of the air conditioner Flowchart showing transition determination operation of abnormality detection of the air conditioner according to the first embodiment Flowchart showing the abnormality detection operation of the opening/closing device of the air conditioner Flowchart showing the rest of FIG. Flowchart showing the refrigerant leak detection operation of the air conditioner according to the first embodiment Flowchart showing the transition determination operation for preventing sticking of the air conditioner according to the second embodiment Flowchart showing the transition determination operation for preventing sticking of the air conditioner according to the third embodiment Flowchart showing transition determination operation of abnormality detection of the air conditioner according to the fourth embodiment

A first invention includes: an outdoor unit having a compressor; an indoor unit having a user-side heat exchanger; a refrigerant pipe connecting the outdoor unit and the indoor unit; and a switching device disposed in the refrigerant pipe. In the air conditioning apparatus, the control section performs a sticking prevention operation in which the opening/closing device is operated to open and close when there is no refrigerant leakage.
Thereby, it is possible to prevent the opening/closing device from not opening or closing for a long period of time, and to suppress the sticking of the opening/closing device. Therefore, when refrigerant leakage occurs, the opening/closing device can be easily operated appropriately, and the amount of refrigerant leaking from the indoor unit can be effectively suppressed.

In a second invention, the refrigerant pipe has a liquid side pipe and a gas side pipe, and the switching device includes a first switching device that opens and closes the liquid side pipe connected to the indoor unit, and a first switching device that opens and closes the liquid side pipe connected to the indoor unit. and a second opening/closing device that opens and closes the gas side piping connected to the machine.
Thereby, each of the liquid side piping and the gas side piping connected to the indoor unit can be opened and closed, and when refrigerant leakage occurs, the amount of refrigerant leaking from the indoor unit can be effectively suppressed.

In a third aspect of the invention, the control unit executes the sticking prevention operation in which the first opening/closing device and the second opening/closing device are opened/closed.
This can prevent the first opening/closing device and the second opening/closing device from not opening or closing for a long period of time, and can prevent the first opening/closing device and the second opening/closing device from sticking together. Therefore, when a refrigerant leak occurs, the liquid side pipe and the gas side pipe connected to the indoor unit can be appropriately opened and closed.

In a fourth aspect of the invention, the liquid side piping is provided with a throttle device that controls the flow rate of refrigerant between the first opening/closing device and the usage side heat exchanger.
Thereby, the flow rate of refrigerant flowing through the user-side heat exchanger can be controlled by the throttle device.

The fifth invention includes a plurality of indoor units arranged in parallel, each of the indoor units being provided with the first opening/closing device and the second opening/closing device, and each of the indoor units being provided with the throttling device.
As a result, in an air conditioning apparatus including a plurality of the indoor units arranged in parallel, the amount of refrigerant leaking from each indoor unit can be effectively reduced.

In a sixth aspect of the present invention, when executing the sticking prevention operation, the control section executes the sticking prevention operation for the opening/closing devices of all the indoor units when the compressor is stopped.
As a result, it is possible to perform the opening/closing device sticking preventive operation for all indoor units while suppressing the impact received from the flow of refrigerant.

A seventh aspect of the invention is that, when executing the sticking prevention operation, when the compressor is in operation and there is an indoor unit that is not operating, the control unit is configured to The diaphragm device of the indoor unit is controlled to open, and the diaphragm device of the indoor unit in operation is controlled to close, and the sticking prevention operation is executed for the opening/closing device of the indoor unit in operation.
This makes it easier to increase the flow rate of refrigerant in an indoor unit that is not in operation, and makes it easier to decrease the flow rate of refrigerant in an indoor unit that is in operation. Therefore, the opening/closing device corresponding to the indoor unit in operation can be opened/closed in a state where it is hardly affected by the flow of refrigerant. Further, since the refrigerant can be flowed using the indoor unit that is not in operation, it is possible to suppress an excessive pressure rise in the refrigerant circuit even if the opening/closing device is opened or closed.

In the eighth invention, when the control unit performs the sticking prevention operation, if the compressor is in operation and there are multiple indoor units in operation, it closes and controls the throttling device of the first operating indoor unit to perform the sticking prevention operation for the opening and closing device of the first operating indoor unit, and then closes and controls the throttling device of the second operating indoor unit to perform the sticking prevention operation for the opening and closing device of the second operating indoor unit.
As a result, when the sticking prevention operation is performed, if the compressor is in operation and there are multiple indoor units in operation, the sticking prevention operation is performed separately for the first operating indoor unit and the second operating indoor unit. Therefore, when the sticking prevention operation is performed for the opening and closing device of one of the first and second operating indoor units, the other of the first and second operating indoor units can be used to flow the refrigerant, thereby suppressing excessive pressure rise in the refrigerant circuit.

In a ninth invention, when executing the sticking preventive operation, the control section executes the sticking preventive operation for the opening/closing device of the indoor unit that is not operating.
Thereby, when the compressor is in operation, sticking prevention operation can be performed for the opening/closing device of the indoor unit that is not in operation.

In a tenth invention, the control section executes the sticking prevention operation again after a first predetermined period of time has elapsed since the execution of the sticking prevention operation.
Thereby, the sticking preventive operation can be executed at every first predetermined time period, and the sticking preventive operation can be executed with necessary and sufficient frequency.

In an eleventh invention, the control unit executes the sticking prevention operation when the operating frequency of the compressor is equal to or lower than a predetermined value.
This makes it easy to open and close the opening/closing device when the flow rate of the refrigerant is small, and the opening/closing device is less susceptible to impact from the flow of the refrigerant.

A twelfth aspect of the present invention further includes an input unit that inputs permission to transition to the sticking prevention operation, and the control unit executes the sticking prevention operation when detecting an input by the input unit.
This allows permission to switch to the sticking prevention operation to be input to the control unit, so that the control unit can be permitted to switch to the sticking prevention operation at any timing.

In the thirteenth invention, the control unit controls at least one of the first opening/closing device and the second opening/closing device to be closed while the throttling device is open, and executes abnormality determination control to determine an abnormal state of the opening/closing device that is controlled to be closed among the first opening/closing device and the second opening/closing device.
As a result, an abnormal state of the first opening and closing device and the second opening and closing device can be determined based on whether or not the refrigerant flowing through the indoor unit is blocked by the opening and closing device that has been controlled to close.

A fourteenth invention includes a first temperature sensor that is arranged in the liquid side piping between the first switchgear and the user-side heat exchanger and detects the refrigerant temperature, and a first temperature sensor that detects the refrigerant temperature; a second temperature sensor disposed in the gas side piping between the chambers and detects the refrigerant temperature; One switchgear is controlled to open and the other switchgear is controlled to close, and when the difference value between the temperatures detected by the first temperature sensor and the second temperature sensor is higher than a predetermined temperature, the other switchgear is abnormal. It is determined that the state is the same.
Thereby, the refrigerant temperature between the first switching device and the usage-side heat exchanger and the refrigerant temperature between the second switching device and the usage-side heat exchanger can be detected. Therefore, it is possible to determine whether or not the refrigerant is cut off based on the temperature difference between the liquid side and the gas side of the user-side heat exchanger, thereby determining whether the opening/closing device is in an abnormal state.

A fifteenth aspect of the invention is that, in the abnormality determination control, the control unit throttles the throttle device and controls opening of an upstream opening/closing device in a refrigerant flow direction of the first opening/closing device and the second opening/closing device. At the same time, the downstream switching device is controlled to close, and it is determined whether the downstream switching device is in an abnormal state.
As a result, the throttle device controls the closing of the opening/closing device on the downstream side in the flow direction of the refrigerant in a state where the flow rate of refrigerant flowing to the downstream opening/closing device is reduced, so that the impact received by the opening/closing device from the refrigerant can be suppressed.

The sixteenth invention is such that, in the abnormality determination control, the control unit determines whether or not the downstream opening and closing device is in an abnormal state, and then controls the downstream opening and closing device to open and controls the upstream opening and closing device to close, thereby determining whether or not the upstream opening and closing device is in an abnormal state.
This makes it possible to determine whether an abnormality exists in a switching device located upstream in the flow direction of the refrigerant.

In a seventeenth invention, when the control unit determines that the opening/closing device is in an abnormal state in the abnormality determination control, it notifies that the opening/closing device is in an abnormal state.
This makes it easier to recognize that the opening/closing device is in an abnormal state.

An eighteenth aspect of the invention is that, when the operating frequency of the compressor is below a predetermined value and a second predetermined time has elapsed since executing the abnormality determination control, Executes abnormality determination control.
Thereby, when the impact received from the flow of refrigerant is small, the opening/closing device can be opened and closed to execute abnormality determination control. Further, excessive execution of abnormality determination control can be suppressed.

A nineteenth aspect of the invention includes a second input section for inputting permission to shift to the abnormality determination control, and the control section executes the abnormality determination control when detecting an input from the second input section.
Thereby, the control unit can be permitted to shift to abnormality determination control at any timing.

In a 20th invention, the control unit controls the diaphragm device to close when it is determined in the abnormality determination control that at least one of the first opening and closing device and the second opening and closing device is in an abnormal state.
Thereby, when the opening/closing device is in an abnormal state, the flow of the refrigerant can be regulated by controlling the throttle device to close.

In a twenty-first aspect, the indoor unit includes a refrigerant leak sensor that detects a refrigerant concentration, and the control unit controls the operating frequency of the compressor to a predetermined value when the concentration detected by the refrigerant leak sensor is equal to or higher than a predetermined value. After controlling the amount to be equal to or less than the value, the switching device is brought into a closed state.
As a result, after a refrigerant leak is detected, the operating frequency of the compressor is lowered and the opening/closing device is controlled to close while the flow rate of refrigerant flowing in the refrigerant circuit is small, thereby suppressing the impact of the refrigerant transmitted to the opening/closing device. Thereby, the risk of damage to the switchgear can be reduced and the operational reliability of the switchgear can be improved.

In a twenty-second aspect of the invention, when the concentration detected by the refrigerant leakage sensor is equal to or higher than a predetermined value, the control section closes the throttle device and then brings the opening/closing device into a closed state.
Thereby, after the refrigerant leak is detected, the throttle device is controlled to close and the opening/closing device is controlled to close while the flow rate of refrigerant flowing in the refrigerant circuit is small, thereby suppressing the impact of the refrigerant transmitted to the opening/closing device. Therefore, the risk of damage to the switching device can be reduced, and the operational reliability of the switching device can be improved.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
[1. First embodiment]
FIG. 1 is a diagram showing the configuration of an air conditioner 1 according to the first embodiment.
The air conditioner 1 includes an outdoor unit 20 and a plurality of indoor units 30a, 30b, and 30c. Each of the indoor units 30a, 30b, and 30c is connected in parallel to the outdoor unit 20 via a liquid side pipe 11 and a gas side pipe 12. The liquid side pipe 11 includes liquid side pipes 13a, 13b, and 13c that are branched and connected to the respective indoor units 30a, 30b, and 30c. The gas side pipe 12 includes gas side pipes 14a, 14b, and 14c that are branched and connected to the respective indoor units 30a, 30b, and 30c. The air conditioner 1 circulates the refrigerant compressed by the outdoor unit 20 between the outdoor unit 20 and the indoor units 30a, 30b, and 30c, and air-conditions the conditioned space in which the indoor units 30a, 30b, and 30c are installed. .

Since each indoor unit 30a, 30b, 30c is configured in the same way, in the following explanation, the corresponding component of each indoor unit 30a, 30b, 30c will be given the same numerical code and a subscript. They are distinguished by adding a, b, and c. Furthermore, if there is no particular need to distinguish between corresponding components, only numerical signs may be used and the subscripts a, b, and c may be omitted.

The outdoor unit 20 includes a compressor 201 that compresses refrigerant, an outdoor heat exchanger 202 that exchanges heat with the refrigerant, an outdoor fan 203, an expansion valve 204, and a switching valve 205.
Compressor 201 sucks refrigerant from suction pipe 208, compresses it, and discharges it.
The outdoor heat exchanger 202 exchanges heat between the refrigerant and outdoor air in the outdoor unit 20.

The outdoor fan 203 sends air to the outdoor heat exchanger 202 .
The expansion valve 204 reduces the pressure of the high-pressure refrigerant to expand it. The expansion valve 204 is configured to be adjustable in opening degree. The opening degree of the expansion valve 204 is controlled by the control unit 100. The expansion valve 204 may be a valve that is adjustable in opening degree and can cut off the refrigerant.
The switching valve 205 is configured, for example, as a four-way valve. The switching valve 205 switches the flow of the refrigerant discharged from the compressor 201 and the refrigerant returning to the compressor 201. The switching valve 205 switches the air conditioner 1 between a cooling operation mode and a heating operation mode.

The indoor unit 30 includes an indoor heat exchanger 301 , an indoor fan 302 , an indoor expansion valve 304 , a first temperature sensor 305 , a second temperature sensor 306 , and a refrigerant leak sensor 307 .
The indoor heat exchanger 301 performs heat exchange between the refrigerant supplied from the outdoor unit 20 through the liquid side piping 11 or the gas side piping 12 and indoor air. The indoor heat exchanger 301 corresponds to an example of a user-side heat exchanger.
Indoor fan 302 blows air to indoor heat exchanger 301 .

The indoor expansion valve 304 is an expansion valve disposed in the liquid side pipe 11 between the expansion valve 204 and the indoor heat exchanger 301. In this embodiment, the indoor expansion valve 304 is arranged in the liquid side pipe 13 connected to the indoor heat exchanger 301. Indoor expansion valve 304 is configured similarly to expansion valve 204. Indoor expansion valve 304 corresponds to an example of a throttle device.

A first temperature sensor 305 is provided in the liquid side pipe 13 of the indoor heat exchanger 301. In this embodiment, the first temperature sensor 305 is provided at a connection portion where the liquid side pipe 13 is connected to the indoor heat exchanger 301. The first temperature sensor 305 detects the temperature of the refrigerant and inputs a detection signal to the control unit 100.
A second temperature sensor 306 is provided in the gas side pipe 14 of the indoor heat exchanger 301. In this embodiment, the second temperature sensor 306 is provided at a connection portion where the gas side pipe 14 is connected to the indoor heat exchanger 301. The second temperature sensor 306 detects the temperature of the refrigerant and inputs a detection signal to the control unit 100.

A refrigerant leak sensor 307 is arranged near the indoor heat exchanger 301. The refrigerant leak sensor 307 detects the concentration of refrigerant and inputs a detection signal to the control unit 100. When the concentration of the refrigerant is equal to or higher than a predetermined value, refrigerant leakage is detected.

A first opening/closing device 101 and a second opening/closing device 102 that adjust the flow rate of refrigerant to the indoor unit 30 are provided on both sides of the indoor heat exchanger 301 of the indoor unit 30 .

The first opening/closing device 101 is provided in the liquid side piping 13 connected to the indoor heat exchanger 301. The first opening/closing device 101 of this embodiment is composed of an opening/closing valve such as an electric valve or a solenoid valve. The first opening/closing device 101 can be switched between an open state in which the refrigerant flows and a closed state in which the flow of the refrigerant is blocked. The first opening/closing device 101 is configured such that opening and closing can be controlled by the control unit 100. Further, the first switching device 101 is configured to be in a closed state during a power outage.
Note that the first opening/closing device 101 may be a valve that can be set between an open state and a closed state, and the opening degree of the first opening/closing device 101 may be controlled by the control unit 100.

The second opening/closing device 102 is provided in the gas side piping 14 connected to the indoor heat exchanger 301. The second opening/closing device 102 is configured similarly to the first opening/closing device 101.

In the cooling operation mode of the air conditioner 1, the refrigerant flows in the flow direction F1, and the refrigerant flows through the compressor 201, the switching valve 205, the outdoor heat exchanger 202, the expansion valve 204, the indoor expansion valve 304, the indoor heat exchanger 301, and the switching valve. It flows in the order of valve 205 and returns from switching valve 205 to suction pipe 208 .

In addition, in the heating operation mode of the air conditioner 1, the refrigerant flows in the flow direction F2, and the refrigerant flows through the compressor 201, the switching valve 205, the indoor heat exchanger 301, the indoor expansion valve 304, the expansion valve 204, and the outdoor heat exchanger 202. , the switching valve 205 , and returns from the switching valve 205 to the suction pipe 208 .

FIG. 2 is a block diagram of the control unit 100 of the air conditioner 1 according to the first embodiment.
As shown in FIGS. 1 and 2, the air conditioner 1 includes a control section 100. An operation section 100a composed of a remote control, an operation panel, etc. is connected to the control section 100 by wire or wirelessly. The operating section 100a is provided with a display section 100b. The display section 100b is configured to display the operating state of the operating section 100a and the operating state of the air conditioner 1. The operation unit 100a corresponds to an example of an input unit. The display section 100b corresponds to an example of a notification means.

The control unit 100 controls the operation of the compressor 201, controls the opening degree and opening/closing of the expansion valve 204 and the indoor expansion valve 304, controls switching of the flow path of the switching valve 205, and operates and stops the outdoor fan 203 and the indoor fan 302. control. Further, the control unit 100 controls opening and closing of the first opening/closing device 101 and the second opening/closing device 102.

The control unit 100 operates the expansion valve 204, the indoor expansion valve 304, and the switching valve 205 to switch the air conditioner 1 between the cooling operation mode and the heating operation mode. Further, the control unit 100 controls the operating frequency, operation and stop of the compressor 201, and controls the outdoor fan 203 and the indoor fan 302 in accordance with the target temperature set by operating the operation unit 100a. The conditioned space is air-conditioned according to the conditions.

The control unit 100 executes processing for the sticking prevention operation. In order to execute processing for the sticking prevention operation, the control unit 100 executes processing for an operation for determining whether or not the air conditioning apparatus 1 should transition to sticking prevention.
The control unit 100 also executes processing for an abnormality detection operation of the opening and closing device. The control unit 100 executes processing for a transition determination operation of abnormality detection of the air conditioning device 1 in order to execute processing for an abnormality detection operation of the opening and closing device.
Furthermore, the control unit 100 executes processing for detecting refrigerant leakage from the air conditioning device 1 .

Various types of refrigerants can be used in the air conditioner 1. In recent years, refrigerants such as hydrocarbons, ammonia, and R32 have been used in air conditioners as so-called alternative fluorocarbons. Some of these alternative fluorocarbons are slightly flammable or flammable. In the event of a leak of a slightly flammable or flammable refrigerant, it is necessary to suppress the amount of refrigerant leakage so that the refrigerant concentration in the conditioned space of the indoor unit 30 does not reach the lower flammability limit (LFL). In particular, it is desirable to suppress the amount of refrigerant leakage from the indoor unit 30 installed in the conditioned space or in its vicinity.

FIG. 3 is a flowchart showing a transition determination operation for preventing sticking of the air conditioner 1 according to the first embodiment. FIG. 4 is a flowchart showing the sticking prevention operation of the air conditioner 1. The operations shown in FIGS. 3 and 4 are executed by the control unit 100 controlling each part of the air conditioner 1.

As shown in Fig. 3, when the control unit 100 starts the process of the transition determination operation for sticking prevention, it starts measuring the first predetermined time (step ST11). The first predetermined time is a time for setting an interval for executing the sticking prevention operation. The first predetermined time allows the first opening/closing device 101 and the second opening/closing device 102 to be opened and closed at a necessary and sufficient frequency, and prevents excessive opening and closing, which would cause damage to the opening/closing devices 101 and 102. In this embodiment, as an example, the first predetermined time is set to one week.
When the control unit 100 starts measuring the first predetermined time, it determines whether or not the first predetermined time has elapsed (step ST12).

When the control unit 100 determines that the first predetermined time has not elapsed (step ST12; NO), it executes the process of step ST12.
When the control unit 100 determines that the first predetermined time has elapsed (step ST12; YES), it executes the sticking prevention operation shown in FIG. 4 (step ST13).
After executing the sticking prevention operation, the control unit 100 returns to step ST11 and starts measuring the first predetermined time (step ST11). That is, the control unit 100 executes the sticking prevention operation every first predetermined time period.

As shown in FIG. 4, when starting the sticking prevention operation, the control unit 100 determines whether the compressor 201 is in operation (ON) (step ST21).
When the compressor 201 is in operation (step ST21; YES), the control unit 100 determines whether or not the number of operating indoor units 30 is one (step ST22).

When the number of operating indoor units 30 is one (step ST22; YES), the control unit 100 fully opens the indoor expansion valve 304 of the indoor unit 30 that is not operating (step ST23) as an example of opening control. In this embodiment, the indoor expansion valves 304 of all the indoor units 30 whose operation is stopped are fully opened. This allows the refrigerant to flow through the indoor unit 30 while the operation is stopped. Since the refrigerant can flow through the indoor unit 30 when the operation is stopped, an excessive pressure rise in the refrigerant circuit is suppressed even if the flow of the refrigerant is cut off in the indoor unit 30 when the operation is stopped.
Here, instead of the configuration in which the indoor expansion valves 304 of all the indoor units 30 that are not in operation are fully opened, a configuration may be adopted in which the indoor expansion valves 304 of some of the indoor units 30 that are not in operation are fully opened. . In this case, for example, the indoor units 30a and 30b on the outdoor unit 20 side may be fully opened.

The control unit 100 controls the indoor expansion valve 304 of the indoor unit 30 in operation to close (step ST24). The closing control in step ST24 controls the opening degree of the indoor expansion valve 304 so that the opening degree of the indoor expansion valve 304 is closer to the fully closed side than the current opening degree. Thereby, the flow rate of the refrigerant flowing through the indoor unit 30 during operation is suppressed, and the impact that the opening/closing devices 101 and 102 receive from the flow of the refrigerant when opening and closing is suppressed.

The control unit 100 closes the first opening/closing device 101 corresponding to the indoor unit 30 in operation (step ST25).
The control unit 100 opens the first opening/closing device 101 corresponding to the indoor unit 30 that is in operation (step ST26).
The control unit 100 closes the second opening/closing device 102 corresponding to the indoor unit 30 in operation (step ST27).
The control unit 100 opens the second opening/closing device 102 corresponding to the indoor unit 30 that is in operation (step ST28).
In steps ST25 to ST28, the first opening/closing device 101 and the second opening/closing device 102 of the indoor unit 30 which was in operation are opened and closed, so that the first opening/closing device 101 and the second opening/closing device 102 are prevented from sticking.

The control unit 100 controls the opening of the indoor expansion valve 304 of the indoor unit 30 that is in operation (step ST29). The opening control in step ST29 controls the opening degree of the indoor expansion valve 304 to be the opening degree before the indoor expansion valve 304 is controlled to close in step ST24. This allows the refrigerant to flow at the same flow rate as when the indoor unit 30 is in operation.
The control unit 100 fully closes the indoor expansion valve 304 of the indoor unit 30, which is currently in operation and has been fully opened in step ST23 (step ST30). Thereby, the flow of refrigerant is cut off for the indoor unit 30 whose operation is stopped.

The control unit 100 closes the first opening/closing device 101 corresponding to the indoor unit 30 whose operation is stopped (step ST31).
The control unit 100 opens the first opening/closing device 101 corresponding to the indoor unit 30 whose operation is stopped (step ST32).
The control unit 100 closes the second opening/closing device 102 corresponding to the indoor unit 30 whose operation is stopped (step ST33).
The control unit 100 opens the second opening/closing device 102 corresponding to the indoor unit 30 whose operation is stopped (step ST34).
In steps ST31 to ST34, the first switching device 101 and the second switching device 102 corresponding to the indoor unit 30 that has been stopped are opened and closed, thereby preventing the first switching device 101 and the second switching device 102 from sticking. be done.
Then, the control unit 100 ends the sticking prevention operation when the number of operating indoor units 30 is one.

When the number of operating indoor units 30 is not one, that is, when there is a plurality of indoor units 30 in operation (step ST22; NO), the control unit 100 determines whether the indoor units 30 in operation are "first mover" or "later mover". ” is set for grouping (step ST41). At least one indoor unit 30 in operation may be set in the "starter" and "later" groups. As long as one or more units are set, the setting method for the "starter" and "later" groups is arbitrary. In the present embodiment, when the indoor unit 30a is in operation, the indoor unit 30a is set as the "starter", and the remaining operating indoor units 30b and 30c are set as "later". There is. Further, when the indoor unit 30a is not operating, the indoor unit 30b is set to be the "first mover" and the indoor unit 30c is set to be the "later start". The "first" operating indoor unit 30 corresponds to an example of the first operating indoor unit 30. Furthermore, the indoor unit 30 that is in operation as a “later” corresponds to an example of the second indoor unit 30 that is in operation.

The control unit 100 controls the indoor expansion valve 304 of the indoor unit 30 that is being operated by the "first" to close (step ST42). The closing control in step ST42 is the same closing control as step ST24.
The control unit 100 closes the opening/closing devices 101 and 102 corresponding to the indoor unit 30 that is in operation as the "first mover" (step ST43).
The control unit 100 opens the opening/closing devices 101 and 102 corresponding to the indoor unit 30 that is in operation as the "first mover" (step ST44).
Through steps ST43 and ST44, the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 that is in operation as the "starter" are opened and closed, so that the first switchgear 101 and the second switchgear 102 are prevented from sticking. Prevented. At this time, since the refrigerant can flow through the indoor unit 30 during the "later" operation, excessive pressure rise in the refrigerant circuit is suppressed.
The control unit 100 controls the opening of the indoor expansion valve 304 corresponding to the indoor unit 30 that is being operated by the "starter" (step ST45). The opening control in step ST45 is the same opening control as step ST29.

The control unit 100 closes the indoor expansion valve 304 corresponding to the indoor unit 30 that is in operation as a "later" (step ST46). The closing control in step ST46 is the same closing control as step ST24.
The control unit 100 closes the opening/closing devices 101 and 102 corresponding to the indoor unit 30 that is in operation as a "later" (step ST47).
The control unit 100 opens the opening/closing devices 101 and 102 corresponding to the indoor unit 30 that is in operation as a "later" (step ST48).
In steps ST47 and ST48, the first switching device 101 and the second switching device 102 corresponding to the indoor unit 30 that is in operation as a “later” are opened and closed, so that the first switching device 101 and the second switching device 102 are prevented from sticking. Prevented. At this time, since the refrigerant can flow through the indoor unit 30 that is in operation as the "first", excessive pressure rise in the refrigerant circuit is suppressed.
The control unit 100 controls the opening of the indoor expansion valve 304 corresponding to the indoor unit 30 that is in operation as a “later starter” (step ST49). The opening control in step ST49 is the same opening control as step ST29.

The control unit 100 determines whether there is any indoor unit 30 that is not operating (step ST50).
If the control unit 100 determines that there is no indoor unit 30 in operation (step ST50; YES), it ends the sticking prevention operation when there are a plurality of indoor units 30 in operation.

When there is an indoor unit 30 that is not operating (step ST50; NO), the control unit 100 executes the processes of steps ST31 to ST34 for the indoor unit 30 that is not operating. Then, the control unit 100 ends the sticking prevention operation when there are a plurality of indoor units 30 in operation.

When determining that the compressor 201 is stopped (step ST21; NO), the control unit 100 closes the first opening/closing device 101 corresponding to all indoor units 30 (step ST51).
The control unit 100 opens the first switching devices 101 corresponding to all the indoor units 30 (step ST52).
The control unit 100 closes the second opening/closing devices 102 corresponding to all the indoor units 30 (step ST53).
The control unit 100 opens the second switching devices 102 corresponding to all the indoor units 30 (step ST54).
In steps ST51 to ST54, the first switching device 101 and the second switching device 102 corresponding to the indoor unit 30 that is not in operation are opened and closed, so that the first switching device 101 and the second switching device 102 are prevented from sticking. . At this time, since the compressor 201 is stopped and no refrigerant is flowing, control of the indoor expansion valve 304 is omitted.
Then, the control unit 100 ends the sticking prevention operation when the compressor 201 is stopped.

Here, in the conventional configuration described in Patent Document 1, the opening/closing device is not brought into the closed state unless refrigerant leakage occurs. For this reason, there is a risk that sticking may occur due to the opening/closing device not being in the closed state for a long period of time. Therefore, when a refrigerant leak actually occurs, the opening/closing device does not function properly and the refrigerant circuit cannot be shut off, resulting in an increase in the amount of refrigerant leakage.

On the other hand, in the present embodiment, the switching device 101 is operated even when there is no refrigerant leakage through the processes of steps ST25 to ST28, steps ST31 to ST34, steps ST43 to ST44, steps ST47 to ST48, and steps ST51 to ST54. , 102 are opened and closed. As a result, the opening/closing devices 101 and 102 are moving between the closed state (fully closed) and the open state (fully open), and sticking of the opening/closing devices can be suppressed. Therefore, when refrigerant leakage occurs, the opening/closing devices 101 and 102 can be easily operated appropriately, and the amount of refrigerant leaking from the indoor unit 30 can be effectively suppressed.

In this embodiment, in steps ST25 to ST28 described above, after the first opening/closing device 101 is opened and closed, the second opening/closing device 102 is opened and closed. However, instead of this, the first switching device 101 may be opened and closed after the second switching device 102 is opened and closed. Further, the first opening/closing device 101 and the second opening/closing device 102 may be opened and closed simultaneously.
Similarly, in the present embodiment, in steps ST31 to ST34 described above, after the first switching device 101 is opened and closed, the second switching device 102 is opened and closed, but instead of this, the second switching device 102 is opened and closed. After that, the first opening/closing device 101 may be opened/closed, or the first opening/closing device 101 and the second opening/closing device 102 may be opened/closed simultaneously.

Furthermore, in the present embodiment, in steps ST31 to ST34 described above, all the opening/closing devices 101 and 102 of the indoor unit 30 that is not in operation are simultaneously opened and closed. However, instead of this, steps ST31 to ST34 are executed for each indoor unit 30 that is not operating, and the opening/closing devices 101 and 102 are opened and closed in the order of the indoor units 30 that are not operating. All the opening/closing devices 101 and 102 of the indoor unit 30 may be opened and closed.

As described above, the air conditioner 1 of the present embodiment includes an outdoor unit 20 having a compressor 201, an indoor unit 30 having an indoor heat exchanger 301, and a liquid side connecting the outdoor unit 20 and the indoor unit 30. It includes pipes 11 and 13 and gas side pipes 12 and 14, switching devices 101 and 102 arranged on liquid side pipe 13 and gas side pipe 14, and a control unit 100. In this air conditioner 1, the control unit 100 executes a sticking prevention operation in which the opening/closing devices 101 and 102 are opened and closed when there is no refrigerant leakage.
This prevents the opening/closing devices 101, 102 from not opening or closing for a long period of time, and prevents the opening/closing devices 101, 102 from sticking. Therefore, when refrigerant leakage occurs, the opening/closing devices 101 and 102 can be easily operated appropriately, and the amount of refrigerant leaking from the indoor unit 30 can be effectively suppressed.

In this embodiment, the refrigerant piping has liquid side piping 11, 13 and gas side piping 12, 14. The opening and closing device has a first opening and closing device 101 that opens and closes the liquid side piping 13 connected to the indoor unit 30, and a second opening and closing device 102 that opens and closes the gas side piping 14 connected to the indoor unit 30.
This makes it possible to open and close both the liquid side piping 13 and the gas side piping 14 connected to the indoor unit 30, and in the event of a refrigerant leak, the amount of refrigerant leaking from the indoor unit 30 can be effectively suppressed.

Further, in the present embodiment, the control unit 100 executes a sticking prevention operation in which the first switching device 101 and the second switching device 102 are opened and closed.
This can prevent the first opening/closing device 101 and the second opening/closing device 102 from not opening or closing for a long period of time, and can suppress the first opening/closing device 101 and the second opening/closing device 102 from sticking together. Therefore, when refrigerant leakage occurs, the liquid side pipe 11 and the gas side pipe 12 connected to the indoor unit 30 can be appropriately opened and closed.

Further, in this embodiment, the liquid side pipe 11 is provided with an indoor expansion valve 304 that controls the flow rate of refrigerant between the first opening/closing device 101 and the indoor heat exchanger 301.
Thereby, the flow rate of refrigerant flowing through the indoor heat exchanger 301 can be controlled by the indoor expansion valve 304.

Further, in this embodiment, a plurality of indoor units 30a, 30b, and 30c are arranged in parallel, and each of the indoor units 30a, 30b, and 30c has a first switching device 101a, 101b, and 101c, and a second switching device 102a. , 102b, and 102c are provided, and indoor expansion valves 304a, 304b, and 304c are provided for each of the indoor units 30a, 30b, and 30c.
Thereby, in the air conditioner 1 including a plurality of indoor units 30a, 30b, and 30c arranged in parallel, the amount of refrigerant leaking from each indoor unit 30a, 30b, and 30c can be effectively suppressed.

Furthermore, in this embodiment, when the sticking prevention operation is executed, if the compressor 201 is stopped, the control unit 100 executes the sticking prevention operation for the opening and closing devices 101, 102 of all the indoor units 30.
As a result, for all of the indoor units 30, the sticking prevention operation of the opening and closing devices 101, 102 can be executed while suppressing the impact from the refrigerant flow.

Furthermore, in the present embodiment, when performing the sticking prevention operation, if the compressor 201 is in operation and there is an indoor unit 30 that is not operating, the control unit 100 controls the The indoor expansion valve 304 of the indoor unit 30 in operation is controlled to open, and the indoor expansion valve 304 of the indoor unit 30 in operation is controlled to close, thereby executing a sticking prevention operation for the opening/closing devices 101 and 102 of the indoor unit 30 in operation.
This makes it easier to increase the flow rate of the refrigerant in the indoor unit 30 that is not operating, and makes it easier to decrease the flow rate of the refrigerant in the indoor unit 30 that is in operation. Therefore, the opening/closing devices 101 and 102 corresponding to the indoor unit 30 in operation can be opened and closed in a state where they are not easily affected by the impact from the flow of refrigerant. Further, since the refrigerant can be circulated using the indoor unit 30 that is not in operation, it is possible to suppress an excessive pressure rise in the refrigerant circuit even if the opening/closing devices 101 and 102 are opened and closed.

Furthermore, in the present embodiment, when performing the sticking prevention operation, if the compressor 201 is in operation and there are a plurality of indoor units 30 in operation, the control unit 100 performs the "first" operation. The indoor expansion valve 304 of the indoor unit 30 inside is controlled to close, and a sticking prevention operation is executed for the opening/closing devices 101 and 102 of the indoor unit 30 that is currently in operation. After that, the indoor expansion valve 304 of the indoor unit 30 that is in operation as a "later" is controlled to close, and a sticking prevention operation is performed for the opening/closing devices 101 and 102 of the indoor unit 30 that is in operation as a "later".
As a result, when performing the sticking prevention operation, if the compressor 201 is in operation and there are multiple indoor units 30 in operation, the "first" operating indoor unit 30 and the "later The sticking prevention operation is performed for the indoor units 30 that are currently in operation. For this reason, when performing sticking prevention operation for the opening/closing devices 101 and 102 of the indoor units 30 that are in operation in one of the "earlier" and "later" indoor units, the 30 to allow the refrigerant to flow, it is possible to suppress excessive pressure rise in the refrigerant circuit.

Furthermore, in the present embodiment, when executing the sticking preventive operation, the control unit 100 executes the sticking preventive operation for the opening/closing devices 101 and 102 of the indoor unit 30 that is not in operation.
Thereby, when the compressor 201 is in operation, the sticking prevention operation can be executed for the opening/closing devices 101 and 102 of the indoor units that are not in operation.

Further, in the present embodiment, the control unit 100 executes the sticking prevention operation again after a first predetermined period of time has elapsed since the execution of the sticking prevention operation.
Thereby, the sticking preventive operation can be executed at every first predetermined time period, and the sticking preventive operation can be executed with necessary and sufficient frequency.

Figure 5 is a flowchart showing the transition determination operation for abnormality detection of the air conditioning apparatus 1 of the first embodiment. Figure 6 is a flowchart showing the abnormality detection operation of the opening and closing device of the air conditioning apparatus 1. Figure 7 is a flowchart showing the rest of Figure 6. The operations in Figures 5 to 7 are executed by the control unit 100 controlling each part of the air conditioning apparatus 1.

As shown in FIG. 5, the control unit 100 starts measuring the second predetermined time after starting the processing of the abnormality detection transition determination operation (step ST101). The second predetermined time is the shortest time interval for performing the abnormality detection operation. Thereby, it is possible to suppress excessive abnormality detection operations of the opening/closing device. That is, it is possible to prevent the first opening/closing device 101 and the second opening/closing device 102 from being opened and closed excessively and causing wear and tear on the opening/closing devices 101 and 102. In this embodiment, the second predetermined time is set to one month, as an example.

The control unit 100 determines whether there is an instruction to lower the operating frequency of the compressor 201 (step ST102).
If there is no instruction to lower the operating frequency of the compressor 201 (step ST102; NO), the control unit 100 executes the process of step ST102.
If there is an instruction to lower the operating frequency of the compressor 201 (step ST102; YES), the control unit 100 determines whether the operating frequency of the compressor 201 is below a predetermined value (step ST103). The predetermined value in step ST103 is set to an operating frequency where the flow rate of the refrigerant is small and the opening/closing devices 101, 102 are hardly affected by the impact from the flow of the refrigerant when the opening/closing devices 101, 102 are opened or closed.

When the control unit 100 determines that the operation frequency of the compressor 201 is not equal to or lower than the predetermined value (step ST103; NO), the control unit 100 executes the process of step ST102.
When the control unit 100 determines that the operation frequency of the compressor 201 is equal to or lower than the predetermined value (step ST103; YES), the control unit 100 determines whether or not the operation frequency is not 0 (step ST103).
When the control unit 100 determines that the operating frequency of the compressor 201 is 0 (step ST104; NO), it stops the operation of the air-conditioning apparatus 1 (step ST107) and executes the process of step ST102.

When the control unit 100 determines that the operating frequency of the compressor 201 is not 0 (step ST104; YES), the control unit 100 determines whether the second predetermined time has elapsed (step ST105). Thereby, it is determined whether the second predetermined time has elapsed in a state where the flow rate of the refrigerant is low.
If the control unit 100 determines that the second predetermined time has not yet elapsed (step ST105; NO), it executes the process of step ST102.
If the control unit 100 determines that the second predetermined time has elapsed (step ST105; YES), it executes the abnormality detection operation of the opening/closing device shown in FIGS. 6 and 7 (step ST106).
When the abnormality detection operation of the opening/closing device is completed, the control unit 100 returns to step ST101 and executes the process of step ST101.

In FIGS. 6 and 7, the abnormality detection operation of the opening/closing device is performed for each of the indoor units 30a, 30b, and 30c. In this embodiment, the flowchart of the abnormality detection operation of the opening/closing device shown in FIGS. 6 and 7 is repeated in the order of the indoor unit 30a, the indoor unit 30b, and the indoor unit 30c. The abnormality detection operation of the switching device corresponds to an example of abnormality determination control of the switching device.
As shown in FIG. 6, when the control unit 100 starts processing the abnormality detection operation of the opening/closing device, it determines whether or not it is in the cooling operation mode (step ST110). Thereby, the refrigerant flow directions F1 and F2 are determined, and it is determined which of the first opening/closing device 101 and the second opening/closing device 102 is located upstream in the refrigerant distribution direction.

When the control unit 100 determines that the mode is the cooling operation mode (step ST110; YES), the indoor expansion valve 304 is controlled to close and throttled (step ST111). By reducing the refrigerant flow rate by throttling the indoor expansion valve 304 and then closing the second opening/closing device 102 on the downstream side, it is possible to suppress the impact on the second opening/closing device 102 in the closed state.
The control unit 100 opens the first switching device 101 corresponding to the upstream side and closes the second switching device 102 corresponding to the downstream side (step ST112). As a result, when the second opening/closing device 102 functions normally, the second opening/closing device 102 is in the closed state, so that the refrigerant is cut off. Therefore, the refrigerant remains in the indoor heat exchanger 301, and no heat exchange is performed in the indoor heat exchanger 301. Therefore, the temperature difference between the refrigerant in the liquid side pipe 13 on the upstream side of the indoor heat exchanger 301 and the refrigerant in the gas side pipe 14 on the downstream side becomes small.

The control unit 100 fully opens the indoor expansion valve 304 (step ST113). This allows the refrigerant to easily flow into the indoor heat exchanger 301 when there is an abnormality in the second opening/closing device 102.
The control unit 100 determines whether the third predetermined time has elapsed (step ST114). The third predetermined time in step ST114 is set as a time when the refrigerant staying in the indoor heat exchanger 301 stops exchanging heat with the indoor air. In this embodiment, four minutes is set as an example of the third predetermined time.

The control unit 100 determines whether the refrigerant temperature in the liquid side pipe 13 and the refrigerant temperature in the gas side pipe 14 of the indoor heat exchanger 301 are equal to or lower than a predetermined value (step ST115). In this embodiment, the difference value between the temperature detected by the first temperature sensor 305 provided in the liquid side pipe 13 and the temperature detected by the second temperature sensor 306 provided in the gas side pipe 14 is calculated. Then, it is determined whether the difference value of the detected temperatures is less than or equal to a small predetermined value.
Here, when the second opening/closing device 102 operates normally, the flow of the refrigerant is blocked and the refrigerant remains in the indoor heat exchanger 301 . Therefore, heat exchange between the refrigerant and the indoor air is no longer performed in the indoor heat exchanger 301, and the temperature difference of the refrigerant between the liquid side pipe 13 and the gas side pipe 14 becomes small. On the other hand, if the second switching device 102 is abnormal, the refrigerant continues to flow through the indoor heat exchanger 301, and the indoor heat exchanger 301 continues to exchange heat between the refrigerant and the indoor air. Therefore, a temperature difference of the refrigerant occurs between the liquid side pipe 13 and the gas side pipe 14. Therefore, in step ST115, in order to determine whether or not there is an abnormality in the second switching device 102, it is determined whether the refrigerant temperature of the liquid side pipe 11 and the refrigerant temperature of the gas side pipe 12 of the indoor heat exchanger 301 are below a predetermined value. Determine whether or not.

When the control unit 100 determines that the refrigerant temperature in the liquid side pipe 13 and the refrigerant temperature in the gas side pipe 14 of the indoor heat exchanger 301 are below a predetermined value (step ST115; YES), the control unit 100 controls the first switching device corresponding to the upstream side. 101 is closed, and the second switching device 102 corresponding to the downstream side is opened (step ST116).
The control unit 100 determines whether the third predetermined time has elapsed (step ST117). Step ST117 is similar to step ST114.
The control unit 100 determines whether the refrigerant temperature in the liquid side pipe 13 and the refrigerant temperature in the gas side pipe 14 of the indoor heat exchanger 301 are equal to or lower than a predetermined value (step ST118). Step ST118 is similar to step ST115.

When the control unit 100 determines that the refrigerant temperature in the liquid side pipe 13 and the refrigerant temperature in the gas side pipe 14 of the indoor heat exchanger 301 are equal to or lower than the predetermined values (step ST118; YES), the control unit 100 opens the first switching device 101. (Step ST119). This returns the first opening/closing device 101 to its original state.
Then, the control unit 100 ends the abnormality detection operation of the switchgear.

When the control unit 100 determines that the refrigerant temperature in the liquid side pipe 13 of the indoor heat exchanger 301 and the refrigerant temperature in the gas side pipe 14 are not equal to or lower than a predetermined value (step ST115; NO), it determines that there is an abnormality in the second opening and closing device 102 and notifies the abnormality of the second opening and closing device 102 (step ST122). As a means for notifying the abnormality of the second opening and closing device 102, it is possible to configure it to display on the operation screen 100b that the second opening and closing device 102 is abnormal, or to control a sound source as an example of a notifying means (not shown) to sound an alarm.
The control unit 100 fully closes the indoor expansion valve 304 (step ST121), thereby blocking the flow of refrigerant.
Then, the control unit 100 ends the operation of detecting an abnormality in the opening and closing device.

If the control unit 100 determines that the refrigerant temperature in the liquid side piping 13 and the refrigerant temperature in the gas side piping 14 of the indoor heat exchanger 301 are not below a predetermined value (step ST118; NO), it determines that there is an abnormality in the first opening and closing device 101 and reports the abnormality in the first opening and closing device 101 (step ST120).
The control unit 100 fully closes the indoor expansion valve 304 (step ST121), and ends the operation of detecting an abnormality in the opening and closing device.

When the control unit 100 is not in the cooling operation mode, that is, in the heating operation mode (step ST110; NO), the control unit 100 controls the indoor expansion valve 304 to close and throttle it (step ST130 in FIG. 7). The refrigerant flow rate is reduced by throttling the indoor expansion valve 304.
The control unit 100 opens the second switching device 102 corresponding to the upstream side, and closes the first switching device 101 corresponding to the downstream side (step ST131).
Steps ST131 to ST141 shown in FIG. 7 are the same as steps ST112 to ST121 except that the upstream switching device and the downstream switching device are opposite to the switching devices of steps ST112 to ST121 shown in FIG. , detailed explanation will be omitted.

Here, in the conventional configuration described in Patent Document 1, the switchgear is not closed unless refrigerant leakage occurs, so the switchgear may become stuck, reducing the reliability of the switchgear. We had the challenge of doing so.

In contrast, in this embodiment, by processing steps ST112 to ST115, steps ST116 to ST118, steps ST131 to ST134, and steps ST135 to ST137, it is determined whether the refrigerant is normally shut off when the opening and closing devices 101 and 102 are in the closed state. Therefore, if it is determined that the opening and closing devices 101 and 102 are abnormal, the opening and closing devices 101 and 102 can be repaired or replaced, improving the reliability of the opening and closing devices 101 and 102.

As described above, the air conditioner 1 of the present embodiment includes an outdoor unit 20 having a compressor 201, an indoor unit 30 having an indoor heat exchanger 301, and a liquid side connecting the outdoor unit 20 and the indoor unit 30. A first opening/closing device 101 opens and closes the liquid side piping 13 connected to the indoor unit 30, and a second opening/closing device 101 opens and closes the gas side piping 13 connected to the indoor unit 30. The control unit 100 includes an opening/closing device 102, an indoor expansion valve 304 that is provided between the first opening/closing device 101 and the indoor heat exchanger 301 and controls the flow rate of refrigerant. In this air conditioner 1, the control unit 100 controls at least one of the first opening/closing device 101 and the second opening/closing device 102 to close while the indoor expansion valve 304 is open. An abnormality detection operation is performed to determine an abnormal state of the opening/closing devices 101 and 102 of the device 102 that have been controlled to close.
Thereby, it is possible to determine whether the first switching device 101 and the second switching device 102 are in an abnormal state depending on whether or not the refrigerant flowing inside the indoor unit 30 is blocked by the switching devices 101 and 102 that are controlled to close.

In this embodiment, the air conditioner 1 includes a first temperature sensor 305 that is arranged in the liquid side pipe 13 between the first switching device 101 and the indoor heat exchanger 301 and detects the refrigerant temperature, and a second switching device 102. A second temperature sensor 306 is provided, which is disposed on the gas side pipe 14 between the indoor heat exchangers 301 and detects the refrigerant temperature. In the abnormality detection operation, the control unit 100 of the air conditioner 1 controls opening of one of the first and second switching devices 101 and 102, and controls the opening of the other of the switching devices 102 and 102. is controlled to close, and if the difference value between the temperatures detected by the first temperature sensor 305 and the second temperature sensor 306 is higher than a predetermined temperature, it is determined that the other opening/closing device 102, 101 is in an abnormal state.
Thereby, the refrigerant temperature between the first switching device 101 and the indoor heat exchanger 301 and the refrigerant temperature between the second switching device 102 and the indoor heat exchanger 301 can be detected. Therefore, it is possible to determine whether the refrigerant is cut off based on the temperature difference between the liquid side and the gas side of the indoor heat exchanger 301, and determine whether the opening/closing devices 101 and 102 are in an abnormal state.

Further, in the present embodiment, in the abnormality detection operation, the control unit 100 throttles the indoor expansion valve 304, and controls the upstream opening/closing device 101 in the refrigerant flow direction of the first opening/closing device 101 and the second opening/closing device 102. 102 to open and control the downstream switching devices 102 and 101 to close, thereby determining whether or not the downstream switching devices 102 and 101 are in an abnormal state.
As a result, the indoor expansion valve 304 controls the closing of the opening/closing devices 102, 101 on the downstream side in the refrigerant distribution direction while the flow rate of refrigerant flowing to the downstream opening/closing devices 102, 101 in the refrigerant distribution direction is reduced. Therefore, the impact that the opening/closing devices 102, 101 receive from the refrigerant can be suppressed.

Further, in the present embodiment, in the abnormality detection operation, the control unit 100 controls the opening of the downstream switching devices 102 and 101 after determining whether the downstream switching devices 102 and 101 are in an abnormal state. At the same time, the upstream switching devices 101 and 102 are controlled to close, and it is determined whether the upstream switching devices 101 and 102 are in an abnormal state.
Thereby, it is also possible to determine whether the opening/closing devices 102, 101 on the upstream side in the refrigerant flow direction are abnormal.

Further, in this embodiment, when the control unit 100 determines that the opening and closing devices 101 and 102 are in an abnormal state in the abnormality detection operation, it notifies that the opening and closing devices 101 and 102 are in an abnormal state.
This makes it easier to recognize that the opening/closing devices 101 and 102 are in an abnormal state.

Furthermore, in the present embodiment, the control unit 100 controls the indoor expansion valve 304 to close when it is determined that at least one of the first opening/closing device 101 and the second opening/closing device 102 is in an abnormal state in the abnormality detection operation. .
Thereby, when the opening/closing devices 101 and 102 are in an abnormal state, the indoor expansion valve 304 can be controlled to close to regulate the flow of refrigerant.

Furthermore, in the present embodiment, when the operating frequency of the compressor 201 is below a predetermined value and a second predetermined time has elapsed since the abnormality detection operation was performed, the control unit 100 detects the abnormality again. Execute detection operation.
Thereby, when the impact received from the flow of refrigerant is small, the opening/closing devices 101 and 102 can be opened and closed to perform an abnormality detection operation. Further, it is possible to suppress execution of excessive abnormality detection operations.

FIG. 8 is a flowchart showing the refrigerant leak detection operation of the air conditioner 1 of the first embodiment. The operation in FIG. 8 is executed by the control unit 100 controlling each part of the air conditioner 1.
As shown in FIG. 8, when the control unit 100 starts processing the refrigerant leakage detection operation, it determines whether or not refrigerant leakage is detected based on the detection result of the refrigerant leakage sensor 307 (step ST201). .

When control unit 100 does not detect a refrigerant leak (step ST201; NO), it executes the process of step ST201.
When the control unit 100 detects a refrigerant leak (step ST201; YES), it continues to operate the indoor fan 302 (step ST202). As a result, the refrigerant leaked into the room is transported by the air blown by the indoor fan 302, and the refrigerant leaked into the room is easily diluted.

The control unit 100 controls the operating frequency of the compressor 201 to decrease (step ST203). The control to lower the operating frequency is performed, for example, as follows. The operating frequency of the compressor 201 before detection is multiplied by the ratio of the operating capacity of the indoor unit 30 in which leakage has been detected to the operating capacity of all indoor units 30. Specifically, for example, if the operating frequency before detection is 60 Hz, the operating capacity of the indoor unit 30 in which leakage was detected is 5 HP (horsepower), and the operating capacity of all indoor units 30 is 15 HP. , 60Hz×(5HP/15HP)=20Hz, the operating frequency is controlled to decrease.

The control unit 100 fully closes the indoor expansion valve 304 in the indoor unit 30 in which leakage has been detected (step ST204). This allows the flow of refrigerant to be regulated.
The control unit 100 closes the first opening/closing device 101 and the second opening/closing device 102 corresponding to the indoor unit 30 in which leakage has been detected (step ST205).
The control unit 100 determines whether the first switching device 101 and the second switching device 102 corresponding to the indoor unit 30 in which no leakage is detected are in the open state (step ST206).

If the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 for which no leakage has been detected are in the open state (step ST206; YES), the control unit 100 continues the operation (step ST207) and removes the refrigerant. The leak detection operation process ends.
If the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 for which no leakage has been detected are not in the open state (step ST206; NO), the control unit 100 stops the operation (step ST208) and stops the refrigerant. The leak detection operation process ends.

Here, in the conventional configuration described in Patent Document 1, the opening/closing device is brought into a closed state when refrigerant leakage occurs. However, if a refrigerant leak occurs, simply closing the switchgear may cause the impact of the refrigerant flowing in the refrigerant circuit to be transmitted to the closed switchgear, causing damage to the switchgear. There is. Therefore, in the conventional configuration, there was a problem that the operational reliability of the switchgear decreased.

In contrast, in the present embodiment, the drive frequency is reduced in step ST203 to reduce the flow rate of the refrigerant, and the indoor expansion valve 304 is further closed in step ST204 to regulate the flow of the refrigerant, and then the first The opening/closing device 101 and the second opening/closing device 102 are in a closed state. Therefore, the impact of the refrigerant flowing in the refrigerant circuit is prevented from being transmitted to the opening/closing devices 101 and 102 in the closed state. Therefore, the risk of damage to the switching devices 101, 102 can be reduced, and the operational reliability of the switching devices 101, 102 can be improved.

Although it is desirable to include step ST204 described above, it may be omitted. That is, the control unit 100 may proceed to step ST205 after executing step ST203.

As described above, the air conditioner 1 of the present embodiment includes an outdoor unit 20 having a compressor 201, an indoor unit 30, and refrigerant pipes 11, 12, 13, 14 that connect the outdoor unit 20 and the indoor unit 30. , opening/closing devices 101 and 102 that open and close the refrigerant pipes 13 and 14, a refrigerant leak sensor 307 that detects refrigerant concentration, and a control unit 100. Then, when the concentration detected by the refrigerant leakage sensor 307 is above a predetermined value, the control unit 100 controls the operating frequency of the compressor 201 to be below a predetermined value, and then closes the opening/closing devices 101 and 102.
As a result, after a refrigerant leak is detected, the operating frequency of the compressor 201 is lowered and the switching devices 101 and 102 are controlled to close while the flow rate of refrigerant flowing in the refrigerant circuit is small. Shock is suppressed. Therefore, the risk of damage to the opening/closing devices 101, 102 can be reduced, and the operational reliability of the opening/closing devices 101, 102 can be improved.

In this embodiment, when the concentration detected by the refrigerant leak sensor 307 is equal to or higher than a predetermined value, the control unit 100 controls the indoor expansion valve 304 to close, and then closes the opening/closing devices 101 and 102.
As a result, after a refrigerant leak is detected, the indoor expansion valve 304 is controlled to close and the switching devices 101 and 102 are controlled to close while the flow rate of refrigerant flowing in the refrigerant circuit is small, thereby suppressing the impact of the refrigerant transmitted to the switching devices. Ru. Therefore, the risk of damage to the opening/closing devices 101, 102 can be reduced, and the operational reliability of the opening/closing devices 101, 102 can be improved.

[2. Second embodiment]
FIG. 9 is a flowchart showing a transition determination operation for preventing sticking of the air conditioner 1 according to the second embodiment. In the second embodiment, constituent parts common to those in the first embodiment are given the same reference numerals and description thereof will be omitted.
The control unit 100 of the air conditioner 1 according to the second embodiment differs from the first embodiment in that the control unit 100 performs the control according to the flowchart shown in FIG. 9 instead of the control according to the flowchart shown in FIG. 3.
As shown in FIG. 9, when the control unit 100 starts the process of the sticking prevention transition determination operation, the control unit 100 determines whether the operating frequency of the compressor 201 is equal to or lower than a predetermined value (step ST61). The predetermined value in step ST61 is set to a frequency where the flow rate of the refrigerant is small and the flow of the refrigerant does not easily impact the opening/closing devices 101 and 102.

When the control unit 100 determines that the operating frequency of the compressor 201 is not below the predetermined value (step ST61; NO), it executes the process of step ST61.
When the control unit 100 determines that the operating frequency of the compressor 201 is equal to or lower than the predetermined value (step ST61; YES), the control unit 100 executes the sticking prevention operation shown in FIG. 4 in step ST62, and returns to step ST61.

In this embodiment, the control unit 100 executes the sticking prevention operation when the operating frequency of the compressor 201 is equal to or less than a predetermined value.
This makes it easier to open and close the opening/closing devices 101, 102 in a state where the flow rate of refrigerant is small, and the opening/closing devices 101, 102 are less susceptible to impact from the flow of refrigerant.

[3. Third embodiment]
10 is a flowchart showing the operation of determining whether to transition to sticking prevention in the air conditioning apparatus 1 of the third embodiment. In the third embodiment, components that are common to the first and second embodiments are given the same reference numerals and descriptions thereof will be omitted.
The operation unit 100a of the air conditioning apparatus 1 of the third embodiment is configured to input permission to transition to the sticking prevention operation to the control unit 100. The operation unit 100a corresponds to an example of an input unit.

The control unit 100 of the air conditioning apparatus 1 of the third embodiment differs from that of the first embodiment in that it performs control according to the flowchart shown in FIG. 10 instead of the control according to the flowchart shown in FIG.
As shown in FIG. 10, the control unit 100 detects the presence or absence of an input from the operation unit 100a, and determines whether or not there is an input for the sticking prevention operation (step ST71).

When the control unit 100 does not detect the input of the sticking prevention operation (step ST71; NO), the control unit 100 executes the process of step ST71.
When the control unit 100 detects the input of the sticking prevention operation (step ST71; YES), the control unit 100 executes the sticking prevention operation shown in FIG. 4 in step ST72, and returns to step ST71.

In this embodiment, the control unit 100 includes an operation unit 100a for inputting permission to shift to the anti-sticking operation, and executes the anti-sticking operation when the control unit 100 detects an input from the operating unit 100a.
Thereby, permission to shift to the sticking prevention operation can be input to the control unit 100. Therefore, the control unit 100 can be permitted to shift to the sticking prevention operation at any timing.

[4. Fourth embodiment]
FIG. 11 is a flowchart showing a transition determination operation for abnormality detection of the air conditioner 1 according to the fourth embodiment. In the fourth embodiment, constituent parts common to those in the first to third embodiments are given the same reference numerals and description thereof will be omitted.
The operation unit 100a of the air conditioner 1 according to the fourth embodiment is configured to input permission for transition to an abnormality detection operation of the opening/closing device to the control unit 100. The operation unit 100a corresponds to an example of a second input unit.

The control unit 100 of the air conditioner 1 according to the fourth embodiment differs from the first embodiment in that the control unit 100 performs the control according to the flowchart shown in FIG. 11 instead of the control according to the flowchart shown in FIG. 5.
As shown in FIG. 11, the control unit 100 detects the presence or absence of an input from the operation unit 100a, and determines whether there is an input for permission to shift to the abnormality detection operation of the opening/closing device (step ST181).

When the control unit 100 does not detect the input of permission to shift to the abnormality detection operation of the opening/closing device (step ST181; NO), the control unit 100 executes the process of step ST181.
When the control unit 100 detects the input of permission to shift to the abnormality detection operation of the switchgear (step ST181; YES), in step ST182, it executes the abnormality detection operation of the switchgear shown in FIGS. 6 and 7, Return to step ST181.

The present embodiment includes an operation unit 101a for inputting permission to shift to an abnormality detection operation of the opening/closing device, and when the control unit 101 detects an input from the operation unit 101a, executes the operation of detecting an abnormality of the opening/closing device.
Thereby, the control unit 101 can be permitted to shift to the abnormality detection operation of the opening/closing device at any timing.

[5. Other embodiments]
Note that although the present invention has been described based on the embodiment, the present invention is not limited to the present embodiment. Since this is merely an example of one embodiment of the present invention, arbitrary changes and applications can be made without departing from the spirit of the present invention.

In the first embodiment, the sticking prevention operation is executed based on the first predetermined time, in the second embodiment, it is executed based on the operating frequency of the compressor 201, and in the third embodiment, it is executed based on the input from the operating unit 100a. The configuration that is executed is explained. However, for example, the sticking prevention operation may be executed based on the first predetermined time period and also based on the operating frequency of the compressor 201. Further, for example, the sticking prevention operation may be executed based on the operating frequency of the compressor 201, and may also be executed based on input from the operating unit 100a. That is, the flowchart shown in FIG. 3 of the first embodiment, the flowchart shown in FIG. 9 of the second embodiment, and the flowchart shown in FIG. 10 of the third embodiment are not limited to the configuration in which the control unit 100 processes them separately. A configuration in which the control unit 100 processes in parallel may be used.

In the first to third embodiments, the abnormality detection operation of the opening/closing device is performed based on the second predetermined time period and the operating frequency of the compressor 201, and in the fourth embodiment, it is performed based on the input from the operating unit 100a. I explained the configuration. However, the abnormality detection operation of the opening/closing device may be executed based on the second predetermined time period and the operating frequency of the compressor 201, and may also be executed based on an input from the operation unit 100a. That is, the flowchart shown in FIG. 5 of the first to third embodiments and the flowchart shown in FIG. 11 of the fourth embodiment are not limited to the configuration in which the control unit 100 processes them separately, but the control unit 100 processes them in parallel. It may be a configuration.

In the above embodiment, as an example, the air conditioner 1 has a package air conditioner (PAC) configuration including one outdoor unit 20 and three indoor units 30, but the present invention is not limited to this. . For example, a room air conditioner (RAC) that includes one outdoor unit 20 and one indoor unit 30, a package air conditioner (PAC) that has multiple indoor units connected to multiple outdoor units, and a building multi-air conditioner ( It is also applicable to the configuration of VRF).

As described above, the air conditioner according to the present invention can be suitably used as an air conditioner capable of suppressing the amount of refrigerant leaking even when refrigerant leakage occurs.

1 Air conditioner 11, 13a, 13b, 13c Liquid side piping (refrigerant piping)
12, 14a, 14b, 14c Gas side piping (refrigerant piping)
20 outdoor unit 30a, 30b, 30c indoor unit 100 control unit 100a operation unit (input unit, second input unit)
101a, 101b, 101c First switching device 102a, 102b, 102c Second switching device 201 Compressor 301a, 301b, 301c Indoor heat exchanger (user side heat exchanger)
302a, 302b, 302c Indoor fan 304a, 304b, 304b Indoor expansion valve (throttle device)
305a, 305b, 305c First temperature sensor 306a, 306b, 306c Second temperature sensor 307a, 307b, 307c Refrigerant leak sensor

Claims (23)

an outdoor unit having a compressor;
an indoor unit having a user-side heat exchanger;
refrigerant piping connecting the outdoor unit and the indoor unit;
a switchgear disposed in the refrigerant pipe;
a control unit;
In an air conditioner comprising:
The control unit executes a sticking prevention operation in which the switching device opens and closes when no refrigerant is leaking;
The air conditioner is characterized in that the control unit executes abnormality determination control for determining an abnormal state of the opening/closing device after a predetermined period of time has elapsed since the closing control of the opening/closing device was performed. Equipped with a temperature sensor that detects the temperature of the refrigerant,
The air conditioner according to claim 1, wherein the control unit executes the abnormality determination control based on the temperature detected by the temperature sensor. The refrigerant piping has a liquid side piping and a gas side piping,
The switching device includes a first switching device that opens and closes the liquid side pipe connected to the indoor unit, and a second switching device that opens and closes the gas side pipe connected to the indoor unit. The air conditioner according to claim 1 or claim 2. The air-conditioning apparatus according to claim 3 , wherein the control unit executes the sticking prevention operation by performing an opening and closing operation on the first opening and closing device and the second opening and closing device. The air conditioner according to claim 4, wherein the liquid side piping is provided with a throttle device that controls the flow rate of refrigerant between the first switching device and the usage side heat exchanger. comprising a plurality of the indoor units arranged in parallel,
The first switching device and the second switching device are provided for each indoor unit,
The air conditioner according to claim 5, wherein the diaphragm device is provided for each indoor unit. When the control unit executes the sticking preventive operation, if the compressor is stopped, the control unit executes the sticking preventive operation for the opening/closing devices of all the indoor units. 6. The air conditioner according to 6. When executing the sticking prevention operation, if the compressor is in operation and there is an indoor unit that is out of operation, the control unit controls the throttle device of the indoor unit that is out of operation. 6 or 7, wherein the locking prevention operation is performed for the opening/closing device of the indoor unit that is in operation by controlling the throttle device to open and closing the throttle device of the indoor unit that is in operation. Air conditioner described in. When executing the sticking prevention operation, when the compressor is in operation and there are a plurality of the indoor units in operation, the control unit controls the After controlling the throttle device to close and performing the sticking prevention operation for the opening/closing device of the indoor unit in the first operation, controlling the throttle device in the indoor unit in a second operation to close it; The air conditioner according to any one of claims 6 to 8, wherein the sticking prevention operation is performed for the opening/closing device of the indoor unit during the second operation. The air conditioner according to claim 8 or 9, wherein when executing the sticking preventive operation, the control unit executes the sticking preventive operation for the opening/closing device of the indoor unit that is not operating. . The air conditioner according to any one of claims 1 to 10, wherein the control unit executes the sticking prevention operation again after a first predetermined period of time has elapsed since the execution of the sticking prevention operation. Device. The air-conditioning apparatus according to any one of claims 1 to 11, wherein the control unit executes the sticking prevention operation when an operating frequency of the compressor is equal to or lower than a predetermined value. comprising an input section for inputting permission to shift to the sticking preventive driving,
The air conditioner according to any one of claims 1 to 12, wherein the control unit executes the sticking prevention operation when detecting an input from the input unit. The control unit controls at least one of the first opening and closing device and the second opening and closing device to close while the diaphragm device is open, and controls the opening and closing of the first opening and closing device and the second opening and closing device that are controlled to close. The air conditioner according to claim 5, wherein abnormality determination control is executed to determine an abnormal state of the device. a first temperature sensor arranged in the liquid side piping between the first switching device and the usage side heat exchanger to detect refrigerant temperature;
a second temperature sensor arranged in the gas side piping between the second switching device and the usage side heat exchanger to detect refrigerant temperature;
In the abnormality determination control, the control unit controls one of the first switching device and the second switching device to open and controls the other switching device to close, and controls the first switching device and the second switching device to close. The air conditioner according to claim 14, wherein the other opening/closing device is determined to be in an abnormal state when a difference value between the temperatures detected by the second temperature sensor is higher than a predetermined temperature. In the abnormality determination control, the control unit throttles the throttle device, controls the opening and closing of the upstream switching device in the refrigerant flow direction of the first switching device and the second switching device, and also controls the opening and closing of the downstream switching device. 16. The air conditioning apparatus according to claim 15, wherein the apparatus is controlled to close and it is determined whether or not the downstream opening/closing device is in an abnormal state. The air conditioning apparatus according to claim 16, characterized in that, in the abnormality determination control, the control unit determines whether or not the opening and closing device on the downstream side is in an abnormal state, and then controls the opening and closing device on the downstream side to open and the opening and closing device on the upstream side to close, thereby determining whether or not the opening and closing device on the upstream side is in an abnormal state. When the control unit determines that the switchgear is in an abnormal state in the abnormality determination control, the control unit notifies that the switchgear is in an abnormal state.
The air conditioner according to any one of claims 14 to 17. The air conditioning apparatus according to any one of claims 14 to 18, characterized in that when the operating frequency of the compressor is equal to or lower than a predetermined value, if a second predetermined time has elapsed since the abnormality determination control was executed, the control unit executes the abnormality determination control again. a second input unit for inputting permission for transition to the abnormality determination control,
The air-conditioning apparatus according to any one of claims 14 to 19, wherein the control unit executes the abnormality determination control when detecting an input via the second input unit. The control unit controls the diaphragm device to close when it is determined that at least one of the first opening and closing device and the second opening and closing device is in an abnormal state in the abnormality determination control. 21. The air conditioner according to any one of 14 to 20. The indoor unit includes a refrigerant leak sensor that detects refrigerant concentration,
The control unit controls the operating frequency of the compressor to be below a predetermined value when the concentration detected by the refrigerant leakage sensor is above a predetermined value, and then closes the opening/closing device. 6. The air conditioner according to 5 or 6. The air conditioner according to claim 22, wherein the control unit closes the expansion device and then closes the opening and closing device when the concentration detected by the refrigerant leakage sensor is equal to or higher than a predetermined value.

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