JP2021131194A - Air conditioner - Google Patents

Abstract

To restrain fixing of an opening and closing device, and to restrain a leakage amount of a refrigerant from an indoor unit, in an air conditioner.SOLUTION: An air conditioner 1 includes an outdoor unit 20 having a compressor 201, an indoor unit 30 having a utilization side heat exchanger 301, refrigerant piping 11, 12, 13, 14 for connecting the outdoor unit 20 with the indoor unit 30, opening and closing devices 101, 102 arranged in the refrigerant piping 13, 14, and a control unit 100. The control unit 100 executes fixing preventive operation for opening and closing the opening and closing devices 101, 102 when a refrigerant is not leaked.SELECTED DRAWING: Figure 1

Description

The present invention relates to an air conditioner.

Conventionally, in an air conditioner, a configuration is known in which an opening / closing device is provided in a refrigerant pipe to suppress a leakage amount of the refrigerant when a leakage of the refrigerant occurs (see, for example, 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 the leakage of the refrigerant is detected, the upstream opening and closing of the indoor heat exchanger is opened and closed. The amount of refrigerant leakage is reduced by closing the device and the downstream switchgear.

International Publication No. 2017/20306

However, in the conventional air conditioner, the switchgear is not closed unless a refrigerant leak occurs. Therefore, sticking may occur by not closing the switchgear for a long period of time. If the switchgear is stuck, the switchgear cannot be closed when the refrigerant leaks, and the amount of refrigerant leaked from the indoor unit may increase.
The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress sticking of a switchgear in an air conditioner and to suppress a leakage amount of a refrigerant from an indoor unit.

In order to solve the above problems, the present invention is arranged in the outdoor unit having a compressor, the indoor unit having a heat exchanger on the user side, the refrigerant pipe connecting the outdoor unit and the indoor unit, and the refrigerant pipe. In the air conditioner including the opening / closing device and the control unit, the control unit executes a sticking prevention operation for opening / closing the opening / closing device when the refrigerant does not leak.
According to this, even if the refrigerant does not leak, the switchgear is opened and closed, so that the switchgear can be suppressed from sticking.

According to the present invention, since the sticking of the switchgear can be suppressed, it is easy to operate the switchgear appropriately when the refrigerant leaks, and the amount of the refrigerant leaking from the indoor unit can be effectively suppressed.

The figure which shows the structure of the air conditioner which concerns on 1st Embodiment Block diagram of the control unit of the air conditioner according to the first embodiment A flowchart showing a transition determination operation for preventing sticking of the air conditioner of the first embodiment. Flow chart showing the sticking prevention operation of the air conditioner Flow chart showing transition determination operation of abnormality detection of the air conditioner of the first embodiment Flow chart showing anomaly detection operation of the switchgear of the air conditioner Flow chart showing the rest of FIG. Flow chart showing the leakage detection operation of the refrigerant of the air conditioner of the first embodiment A flowchart showing a transition determination operation for preventing sticking of the air conditioner of the second embodiment. A flowchart showing a transition determination operation for preventing sticking of the air conditioner according to the third embodiment. Flow chart showing the transition determination operation of abnormality detection of the air conditioner of the fourth embodiment

The first invention comprises an outdoor unit having a compressor, an indoor unit having a heat exchanger on the user side, a refrigerant pipe connecting the outdoor unit and the indoor unit, and a switchgear arranged in the refrigerant pipe. In the air conditioner including the control unit, the control unit executes a sticking prevention operation for opening and closing the switchgear when the refrigerant does not leak.
As a result, it is possible to prevent the switchgear from not opening and closing for a long period of time, and to prevent the switchgear from sticking. Therefore, when the refrigerant leaks, it is easy to operate the switchgear appropriately, and the amount of the refrigerant leaking from the indoor unit can be effectively suppressed.

In the second invention, the refrigerant pipe has a liquid-side pipe and a gas-side pipe, and the switchgear includes a first switchgear that opens and closes the liquid-side pipe connected to the indoor unit, and the indoor unit. It has a second switchgear that opens and closes the gas side pipe connected to the machine.
As a result, each of the liquid side pipe and the gas side pipe connected to the indoor unit can be opened and closed, and when a refrigerant leaks, the amount of the refrigerant leaking from the indoor unit can be effectively suppressed.

In the third invention, the control unit executes the sticking prevention operation for opening and closing the first switchgear and the second switchgear.
As a result, it is possible to prevent the first switchgear and the second switchgear from not opening and closing for a long period of time, and it is possible to suppress the sticking of the first switchgear and the second switchgear. Therefore, when the refrigerant leaks, the liquid side pipe and the gas side pipe connected to the indoor unit can be appropriately opened and closed.

In the fourth invention, the liquid side piping is provided with a throttle device for controlling the flow rate of the refrigerant between the first switchgear and the utilization side heat exchanger.
As a result, the flow rate of the refrigerant flowing through the heat exchanger on the user side can be controlled by the throttle device.

A fifth invention comprises a plurality of the indoor units arranged in parallel, each of the indoor units is provided with the first switchgear and the second switchgear, and the throttle is provided for each indoor unit. A device is provided.
As a result, in an air conditioner including the plurality of indoor units arranged in parallel, the amount of refrigerant leaking from each indoor unit can be effectively suppressed.

In the sixth invention, when the control unit executes the sticking prevention operation, when the compressor is stopped, the control unit executes the sticking prevention operation for the opening / closing devices of all the indoor units.
As a result, it is possible to carry out the sticking prevention operation of the switchgear while suppressing the impact received from the flow of the refrigerant in all the indoor units.

According to a seventh aspect of the present invention, when the control unit executes the sticking prevention operation, the compressor is in operation and the indoor unit is stopped, if the operation is stopped. The throttle device of the indoor unit is opened and controlled, and the throttle device of the indoor unit during operation is closed and controlled to execute the sticking prevention operation for the opening and closing device of the indoor unit during operation.
As a result, it is easy to increase the flow rate of the refrigerant in the indoor unit that is stopped, and it is easy to decrease the flow rate of the refrigerant in the indoor unit that is in operation. Therefore, the switchgear corresponding to the indoor unit during operation can be opened and closed in a state where it is not easily impacted by the flow of the refrigerant. Further, since the refrigerant can be flowed by using the indoor unit that is stopped, the excessive pressure rise of the refrigerant circuit can be suppressed even if the switchgear is opened and closed.

In the eighth invention, when the control unit executes the sticking prevention operation, the compressor is in operation and there are a plurality of the indoor units in operation, the first operation is in progress. After closing and controlling the throttle device of the indoor unit to execute the sticking prevention operation for the switchgear of the indoor unit during the first operation, the throttle device of the indoor unit during the second operation. Is closed and controlled to execute the sticking prevention operation for the opening / closing device of the indoor unit during the second operation.
As a result, when the sticking prevention operation is executed, when the compressor is in operation and there are a plurality of indoor units in operation, the indoor unit in the first operation and the indoor unit in the second operation are in operation. Divide into indoor units and execute sticking prevention operation. Therefore, when the sticking prevention operation is executed for the opening / closing device of the indoor unit during the operation of one of the first and the second, the refrigerant flows by using the indoor unit during the operation of the other of the first and the second. Therefore, it is possible to suppress an excessive pressure rise in the refrigerant circuit.

In a ninth aspect of the invention, when the control unit executes the sticking prevention operation, the control unit executes the sticking prevention operation with respect to the switchgear of the indoor unit that is stopped.
As a result, when the compressor is in operation, the sticking prevention operation can be executed for the opening / closing device of the indoor unit that is stopped.

In the tenth invention, the control unit executes the sticking prevention operation again after the first predetermined time has elapsed from the execution of the sticking prevention operation.
As a result, the sticking prevention operation can be executed every first predetermined time, and the sticking prevention operation can be executed at a necessary and sufficient frequency.

In the eleventh invention, the control unit executes the sticking prevention operation when the operating frequency of the compressor is equal to or less than a predetermined value.
As a result, the switchgear can be easily opened and closed while the flow rate of the refrigerant is small, and the switchgear is less likely to be impacted by the flow of the refrigerant.

A twelfth invention includes an input unit for inputting permission to shift to the sticking prevention operation, and the control unit executes the sticking prevention operation when the input by the input unit is detected.
As a result, the permission to shift to the sticking prevention operation can be input to the control unit. Therefore, the control unit can be allowed to shift to the sticking prevention operation at an arbitrary timing.

In a thirteenth invention, the control unit controls at least one of the first switchgear and the second switchgear to be closed while the throttle device is open, and the first switchgear and the second switchgear are closed. Of these, the abnormality determination control for determining the abnormal state of the switchgear whose closing control is controlled is executed.
Thereby, the abnormal state of the first switchgear and the second switchgear can be determined depending on whether or not the refrigerant flowing in the indoor unit is shut off by the switchgear controlled to close.

The fourteenth invention is a first temperature sensor arranged in the liquid side pipe between the first opening / closing device and the utilization side heat exchanger to detect the refrigerant temperature, and the second opening / closing device and the utilization side heat exchange. A second temperature sensor, which is arranged in the gas side pipe between the vessels and detects the temperature of the refrigerant, is provided, and the control unit is included in the first opening / closing device and the second opening / closing device in the abnormality determination control. When one opening / closing device is opened and controlled and the other opening / closing device is closed and the difference value between the detected temperatures of the first temperature sensor and the second temperature sensor is higher than a predetermined temperature, the other opening / closing device is abnormal. Determined to be in a state.
Thereby, the refrigerant temperature between the first switchgear and the user side heat exchanger and the refrigerant temperature between the second switchgear and the user side heat exchanger can be detected. Therefore, it is possible to determine whether or not the refrigerant is shut off based on the temperature difference between the liquid side and the gas side of the heat exchanger on the user side, and determine the abnormal state of the switchgear.

In the fifteenth invention, the control unit throttles the throttle device in the abnormality determination control, and opens and controls the switchgear on the upstream side in the flow direction of the refrigerant in the first switchgear and the second switchgear. At the same time, the opening / closing device on the downstream side is controlled to be closed, and it is determined whether or not the opening / closing device on the downstream side is in an abnormal state.
As a result, the throttle device closes and controls the switchgear on the downstream side in the flow direction of the refrigerant in a state where the flow rate of the refrigerant flowing to the switchgear on the downstream side is reduced, so that the impact received by the switchgear from the refrigerant can be suppressed.

In the sixteenth invention, the control unit determines in the abnormality determination control whether or not the switchgear on the downstream side is in an abnormal state, and then controls the opening and closing device on the downstream side to open and controls the switchgear on the upstream side. The opening / closing device of the above is controlled to be closed, and it is determined whether or not the opening / closing device on the upstream side is in an abnormal state.
Thereby, the abnormal state of the switchgear on the upstream side in the flow direction of the refrigerant can be determined.

In the seventeenth invention, 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.
This makes it easier to recognize that the switchgear is in an abnormal state.

In the eighteenth invention, when the operating frequency of the compressor is equal to or less than a predetermined value and the second predetermined time has elapsed after executing the abnormality determination control, the control unit again said. Executes abnormality judgment control.
As a result, when the impact received from the flow of the refrigerant is small, the switchgear can be opened and closed to execute the abnormality determination control. In addition, it is possible to suppress the execution of excessive abnormality determination control.

The nineteenth invention includes a second input unit for inputting permission to shift to the abnormality determination control, and the control unit executes the abnormality determination control when the input by the second input unit is detected.
As a result, the control unit can be allowed to shift to the abnormality determination control at an arbitrary timing.

In the twentieth invention, the control unit closes and controls the diaphragm device when it is determined in the abnormality determination control that at least one of the first switchgear and the second switchgear is in an abnormal state.
As a result, when the switchgear is in an abnormal state, the throttle device can be closed and controlled to regulate the flow of the refrigerant.

In the twenty-first invention, the indoor unit includes a refrigerant leakage sensor that detects a refrigerant concentration, and the control unit determines an operating frequency of the compressor when the detection concentration of the refrigerant leakage sensor is equal to or higher than a predetermined value. After controlling to a value or less, the opening / closing device is closed.
As a result, after the refrigerant leakage is detected, the operating frequency of the compressor is lowered and the switchgear is closed and controlled in a state where the flow rate of the refrigerant flowing in the refrigerant circuit is small, so that the impact of the refrigerant transmitted to the switchgear is suppressed. As a result, the risk of damage to the switchgear can be reduced, and the operational reliability of the switchgear can be improved.

In the 22nd invention, when the detection concentration of the refrigerant leakage sensor is equal to or higher than a predetermined value, the control unit closes the throttle device and then closes the switchgear.
As a result, after the refrigerant leakage is detected, the throttle device is closed and controlled, and the switchgear is closed and controlled while the flow rate of the refrigerant flowing in the refrigerant circuit is small, so that the impact of the refrigerant transmitted to the switchgear is suppressed. Therefore, the risk of damage to the switchgear can be reduced, and the operational reliability of the switchgear can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[1. First Embodiment]
FIG. 1 is a diagram showing a 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. The indoor units 30a, 30b, and 30c are connected to the outdoor unit 20 in parallel by the liquid side pipe 11 and the gas side pipe 12. The liquid side pipe 11 includes liquid side pipes 13a, 13b, 13c that are branched and connected to the indoor units 30a, 30b, 30c. The gas side pipe 12 includes gas side pipes 14a, 14b, 14c that are branched and connected to the indoor units 30a, 30b, 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, 30c, and air-conditions the harmonious space in which the indoor units 30a, 30b, 30c are installed. ..

Since the indoor units 30a, 30b, and 30c are configured in the same manner, in the following description, the corresponding components of the indoor units 30a, 30b, and 30c are designated by the same number and have subscripts. A, b, and c are added to distinguish them. When it is not necessary to distinguish the corresponding components, only the sign of the number may be used and the subscripts a, b, and c may be omitted.

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

The outdoor fan 203 blows air to the outdoor heat exchanger 202.
The expansion valve 204 decompresses and expands the high-pressure refrigerant. The expansion valve 204 is configured so that the opening degree can be adjusted. The opening degree of the expansion valve 204 is controlled by the control unit 100. The expansion valve 204 may be a valve whose opening degree can be adjusted and which can shut off the refrigerant.
The switching valve 205 is composed of, for example, a four-way valve. The switching valve 205 switches the flow of the discharged refrigerant of the compressor 201 and the refrigerant returning to the compressor 201. The switching valve 205 switches between the cooling operation mode and the heating operation mode of the air conditioner 1.

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 leakage sensor 307.
The indoor heat exchanger 301 exchanges heat between the refrigerant supplied from the outdoor unit 20 through the liquid side pipe 11 or the gas side pipe 12 and the indoor air. The indoor heat exchanger 301 corresponds to an example of a user-side heat exchanger.
The indoor fan 302 blows air to the indoor heat exchanger 301.

The indoor expansion valve 304 is an expansion valve arranged in the liquid side pipe 11 between the expansion valve 204 and the indoor heat exchanger 301. In the present embodiment, the indoor expansion valve 304 is arranged in the liquid side pipe 13 connected to the indoor heat exchanger 301. The indoor expansion valve 304 is configured in the same manner as the expansion valve 204. The 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 the present embodiment, the first temperature sensor 305 is provided at the 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 the present embodiment, the second temperature sensor 306 is provided at the 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 leakage sensor 307 is arranged in the vicinity of the indoor heat exchanger 301. The refrigerant leakage sensor 307 detects the concentration of the 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, the leakage of the refrigerant is detected.

A first switchgear 101 and a second switchgear 102 for adjusting the flow rate of the refrigerant to the indoor unit 30 are provided on both sides of the indoor heat exchanger 301 of the indoor unit 30.

The first switchgear 101 is provided in the liquid side pipe 13 connected to the indoor heat exchanger 301. The first switchgear 101 of the present embodiment is composed of a switchgear such as an electric valve or a solenoid valve. The first switchgear 101 can switch between an open state in which the refrigerant flows and a closed state in which the flow of the refrigerant is blocked. The first switchgear 101 is configured so that opening and closing can be controlled by the control unit 100. Further, the first switchgear 101 is configured to be closed in the event of a power failure.
The first switchgear 101 may be a valve that can set a state between the open state and the closed state, and the opening / closing device 101 may be controlled by the control unit 100.

The second switchgear 102 is provided in the gas side pipe 14 connected to the indoor heat exchanger 301. The second switchgear 102 is configured in the same manner as the first switchgear 101.

In the cooling operation mode of the air conditioner 1, the refrigerant flows in the flow direction F1, and the refrigerant flows into 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. The flow flows in the order of the valve 205, and returns from the switching valve 205 to the suction pipe 208.

Further, in the heating operation mode of the air conditioner 1, the refrigerant flows in the flow direction F2, and the refrigerant flows in 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. , Flowing in the order of the switching valve 205, and returning 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 unit 100. An operation unit 100a composed of a remote controller, an operation panel, or the like is connected to the control unit 100 by wire or wirelessly. The operation unit 100a is provided with a display unit 100b. The display unit 100b is configured to display the operating state of the operating unit 100a and the operating state of the air conditioner 1. The operation unit 100a corresponds to an example of an input unit. The display unit 100b corresponds to an example of the notification means.

The control unit 100 controls the operation of the compressor 201, controls the opening and closing of the expansion valve 204 and the indoor expansion valve 304, controls the switching of the flow path of the switching valve 205, and operates and stops the outdoor fan 203 and the indoor fan 302. Perform control of. Further, the control unit 100 controls the 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 between the cooling operation mode and the heating operation mode of the air conditioner 1. Further, the control unit 100 executes control of the operating frequency, operation and stop of the compressor 201, control of the outdoor fan 203 and the indoor fan 302 in accordance with the target temperature set by the operation of the operation unit 100a, and controls the target temperature. Air-condition the harmonized space according to.

The control unit 100 executes the process of the sticking prevention operation. The control unit 100 executes the process of the transition determination operation of the air conditioner 1 to prevent the sticking in order to execute the process of the sticking prevention operation.
In addition, the control unit 100 executes the processing of the abnormality detection operation of the switchgear. The control unit 100 executes the processing of the transition determination operation of the abnormality detection of the air conditioner 1 in order to execute the processing of the abnormality detection operation of the switchgear.
Further, the control unit 100 executes the processing of the refrigerant leakage detection operation of the air conditioner 1.

Various refrigerants used in the air conditioner 1 can be mentioned. In recent years, as so-called CFC substitutes, refrigerants such as hydrocarbons, ammonia, and R32 have been used in air conditioners. Some of these CFC substitutes are slightly flammable or flammable. When a slightly flammable or flammable refrigerant leaks, the amount of refrigerant leaked should be suppressed so that the refrigerant concentration in the harmonious space of the indoor unit 30 does not reach the lower flammability limit (LFL). Is required. In particular, it is desired to suppress the amount of refrigerant leaked from the indoor unit 30 installed in or near the harmonious space.

FIG. 3 is a flowchart showing a transition determination operation for preventing sticking of the air conditioner 1 of the first embodiment. FIG. 4 is a flowchart showing a sticking prevention operation of the air conditioner 1. The operations of FIGS. 3 and 4 are executed by the control unit 100 controlling each unit 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, the control unit 100 starts the measurement for the first predetermined time (step ST11). The first predetermined time is a time for setting an interval for executing the sticking prevention operation. With the first predetermined time, the first switchgear 101 and the second switchgear 102 can be opened and closed with a necessary and sufficient frequency, and it is possible to suppress excessive opening and closing of the switchgear 101 and 102. In the present embodiment, as an example, the first predetermined time is set to one week.
When the control unit 100 starts the measurement of the first predetermined time, the control unit 100 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), the control unit 100 executes the process of step ST12.
When the control unit 100 determines that the first predetermined time has elapsed (step ST12; YES), the control unit 100 executes the sticking prevention operation shown in FIG. 4 (step ST13).
When the control unit 100 executes the sticking prevention operation, the control unit 100 returns to step ST11 and starts the measurement for the first predetermined time (step ST11). That is, the control unit 100 executes the sticking prevention operation every first predetermined time.

As shown in FIG. 4, when the sticking prevention operation is started, the control unit 100 determines whether or not 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 indoor units 30 in operation is one (step ST22).

When the number of indoor units 30 in operation is one (step ST22; YES), the control unit 100 fully opens the indoor expansion valve 304 of the indoor unit 30 that is stopped (step ST23) as an example of open control. In the present embodiment, the indoor expansion valve 304 of all the indoor units 30 that are stopped is fully opened. As a result, the refrigerant can be circulated in the indoor unit 30 that has been stopped. Since the refrigerant can flow through the indoor unit 30 that is stopped, even if the flow of the refrigerant is cut off by the indoor unit 30 that is in operation, an excessive increase in pressure in the refrigerant circuit is suppressed.
Here, instead of the configuration in which the indoor expansion valves 304 of all the indoor units 30 that are stopped are fully opened, the indoor expansion valves 304 of some of the indoor units 30 that are stopped may be 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 closes and controls the indoor expansion valve 304 of the indoor unit 30 during operation (step ST24). The closing control of step ST24 controls the opening degree of the indoor expansion valve 304 so that the opening degree of the indoor expansion valve 304 is on the fully closed side from the present. As a result, the flow rate of the refrigerant flowing in the indoor unit 30 during operation is suppressed, and the impact received from the flow of the refrigerant when the switchgear 101 and 102 are opened and closed is suppressed.

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

The control unit 100 opens and controls the indoor expansion valve 304 of the indoor unit 30 during operation (step ST29). The open control of step ST29 controls the opening degree of the indoor expansion valve 304 so as to be the opening degree before closing control of the indoor expansion valve 304 in step ST24. As a result, the refrigerant of the same flow rate as during operation of the indoor unit 30 is allowed to flow.
The control unit 100 fully closes the indoor expansion valve 304 of the indoor unit 30 that has been stopped and is fully opened in step ST23 (step ST30). As a result, the flow of the refrigerant is cut off for the indoor unit 30 that has been stopped.

The control unit 100 closes the first switchgear 101 corresponding to the indoor unit 30 whose operation is stopped (step ST31).
The control unit 100 opens the first switchgear 101 corresponding to the indoor unit 30 that has been stopped (step ST32).
The control unit 100 closes the second switchgear 102 corresponding to the indoor unit 30 whose operation is stopped (step ST33).
The control unit 100 opens the second switchgear 102 corresponding to the indoor unit 30 that has been stopped (step ST34).
By steps ST31 to ST34, the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 that has been stopped are opened and closed, so that the first switchgear 101 and the second switchgear 102 are prevented from sticking. Will be done.
Then, the control unit 100 ends the sticking prevention operation when the number of operating units of the indoor unit 30 is one.

When the number of indoor units 30 in operation is not one, that is, when the number of indoor units 30 in operation is multiple (step ST22; NO), the control unit 100 determines that the indoor unit 30 in operation is "starter" and "later". Is set for grouping (step ST41). At least one or more indoor units 30 in operation may be set in the "starter" and "later" groups. As long as one or more units are set, the method of setting 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 to "starter", and the remaining indoor units 30b and 30c in operation are set to "late". There is. Further, when the indoor unit 30a is stopped, the indoor unit 30b is set to "starter" and the indoor unit 30c is set to "later". The "starter" operating indoor unit 30 corresponds to an example of the first operating indoor unit 30. Further, the "latecomer" operating indoor unit 30 corresponds to an example of the second operating indoor unit 30.

The control unit 100 closes and controls the indoor expansion valve 304 of the indoor unit 30 during the "starting" operation (step ST42). The closing control in step ST42 is the same closing control as in step ST24.
The control unit 100 closes the opening / closing devices 101 and 102 corresponding to the indoor unit 30 during the "starting" operation (step ST43).
The control unit 100 opens the opening / closing devices 101 and 102 corresponding to the indoor unit 30 during the "starting" operation (step ST44).
In steps ST43 to ST44, the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 in operation of the "starter" are opened and closed, so that the first switchgear 101 and the second switchgear 102 are fixed. Be prevented. At this time, since the refrigerant can flow through the indoor unit 30 during the “late” operation, an excessive increase in pressure in the refrigerant circuit is suppressed.
The control unit 100 opens and controls the indoor expansion valve 304 corresponding to the indoor unit 30 in operation of the “starter” (step ST45). The open control in step ST45 is the same open control as in step ST29.

The control unit 100 closes and controls the indoor expansion valve 304 corresponding to the indoor unit 30 during the “late” operation (step ST46). The closing control in step ST46 is the same closing control as in step ST24.
The control unit 100 closes the opening / closing devices 101 and 102 corresponding to the indoor unit 30 during the “late” operation (step ST47).
The control unit 100 opens the opening / closing devices 101 and 102 corresponding to the indoor unit 30 during the “late” operation (step ST48).
In steps ST47 to ST48, the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 during the "later" operation are opened and closed, so that the first switchgear 101 and the second switchgear 102 are fixed. Be prevented. At this time, since the refrigerant can flow through the indoor unit 30 during the "starting" operation, an excessive increase in pressure in the refrigerant circuit is suppressed.
The control unit 100 opens and controls the indoor expansion valve 304 corresponding to the indoor unit 30 during the “late” operation (step ST49). The open control in step ST49 is the same open control as in step ST29.

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

When the control unit 100 determines that the compressor 201 is stopped (step ST21; NO), the control unit 100 closes the first switchgear 101 corresponding to all the indoor units 30 (step ST51).
The control unit 100 opens the first switchgear 101 corresponding to all the indoor units 30 (step ST52).
The control unit 100 closes the second switchgear 102 corresponding to all the indoor units 30 (step ST53).
The control unit 100 opens the second switchgear 102 corresponding to all the indoor units 30 (step ST54).
In steps ST51 to ST54, the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 that has been stopped are opened and closed, so that the first switchgear 101 and the second switchgear 102 are prevented from sticking. .. At this time, since the compressor 201 is stopped and the refrigerant is not flowing, the 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 switchgear is not closed unless a refrigerant leak occurs. Therefore, sticking may occur by not closing the switchgear for a long period of time. Therefore, when a refrigerant leak actually occurs, the switchgear does not function normally, the refrigerant circuit cannot be interrupted, and there is a problem that the amount of the refrigerant leak increases.

On the other hand, in the present embodiment, the switchgear 101 is processed even when the refrigerant does not leak due to 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 switchgear 101 and 102 move between the closed state (fully closed) and the open state (fully open), and the sticking of the switchgear can be suppressed. Therefore, when the refrigerant leaks, the switchgear 101 and 102 can be easily operated appropriately, and the amount of the refrigerant leaked from the indoor unit 30 can be effectively suppressed.

In the present embodiment, in steps ST25 to ST28 described above, the first switchgear 101 is opened and closed, and then the second switchgear 102 is opened and closed. However, instead of this, the first switchgear 101 may be opened and closed after the second switchgear 102 is opened and closed. Further, the first switchgear 101 and the second switchgear 102 may be opened and closed at the same time.
Similarly, in the present embodiment, in steps ST31 to ST34 described above, the first switchgear 101 is opened and closed, and then the second switchgear 102 is opened and closed. Instead, the second switchgear 102 is opened and closed. After that, the first switchgear 101 may be opened and closed, or the first switchgear 101 and the second switchgear 102 may be opened and closed at the same time.

Further, in the present embodiment, in the above-mentioned steps ST31 to ST34, all the opening / closing devices 101 and 102 of the indoor unit 30 whose operation is stopped are opened / closed at the same time. However, instead of this, steps ST31 to ST34 are executed for each of the indoor units 30 that are stopped, and the opening / closing devices 101 and 102 are opened and closed in the order of the indoor units 30 that are stopped, so that the operation is stopped. All the opening / closing devices 101 and 102 of the indoor unit 30 may be opened / closed.

As described above, the air conditioner 1 of the present embodiment is the liquid side that connects the outdoor unit 20 having the compressor 201, the indoor unit 30 having the indoor heat exchanger 301, and the outdoor unit 20 and the indoor unit 30. The pipes 11 and 13 and the gas side pipes 12 and 14, the opening and closing devices 101 and 102 arranged in the liquid side pipe 13 and the gas side pipe 14, and the control unit 100 are provided. In the air conditioner 1, the control unit 100 executes a sticking prevention operation that opens and closes the switchgear 101 and 102 when the refrigerant does not leak.
As a result, it is possible to prevent the switchgear 101 and 102 from not opening and closing for a long period of time, and to prevent the switchgear 101 and 102 from sticking. Therefore, when the refrigerant leaks, the switchgear 101 and 102 can be easily operated appropriately, and the amount of the refrigerant leaked from the indoor unit 30 can be effectively suppressed.

In the present embodiment, the refrigerant pipe has liquid side pipes 11 and 13 and gas side pipes 12 and 14. The switchgear includes a first switchgear 101 that opens and closes the liquid side pipe 13 connected to the indoor unit 30, and a second switchgear 102 that opens and closes the gas side pipe 14 connected to the indoor unit 30.
As a result, each of the liquid side pipe 13 and the gas side pipe 14 connected to the indoor unit 30 can be opened and closed, and when a refrigerant leaks, the amount of the refrigerant leaking from the indoor unit 30 is effectively suppressed. can.

Further, in the present embodiment, the control unit 100 executes a sticking prevention operation for opening and closing the first switchgear 101 and the second switchgear 102.
As a result, it is possible to prevent the first switchgear 101 and the second switchgear 102 from not opening and closing for a long period of time, and it is possible to suppress the sticking of the first switchgear 101 and the second switchgear 102. Therefore, when the refrigerant leaks, 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 the present embodiment, the liquid side pipe 11 is provided with an indoor expansion valve 304 that controls the flow rate of the refrigerant between the first switchgear 101 and the indoor heat exchanger 301.
Thereby, the flow rate of the refrigerant flowing through the indoor heat exchanger 301 can be controlled by the indoor expansion valve 304.

Further, in the present embodiment, a plurality of indoor units 30a, 30b, 30c arranged in parallel are provided, and the first opening / closing devices 101a, 101b, 101c and the second opening / closing device 102a are provided for each of the indoor units 30a, 30b, 30c. , 102b, 102c are provided, and indoor expansion valves 304a, 304b, 304c are provided for each of the indoor units 30a, 30b, 30c.
As a result, in the air conditioner 1 including a plurality of indoor units 30a, 30b, 30c arranged in parallel, the amount of refrigerant leaking from each indoor unit 30a, 30b, 30c can be effectively suppressed.

Further, in the present embodiment, when the control unit 100 executes the sticking prevention operation, when the compressor 201 is stopped, the control unit 100 executes the sticking prevention operation for all the opening / closing devices 101 and 102 of the indoor unit 30. ..
As a result, it is possible to execute the sticking prevention operation of the switchgear 101 and 102 while suppressing the impact received from the flow of the refrigerant in all the indoor units 30.

Further, in the present embodiment, when the control unit 100 executes the sticking prevention operation, if the compressor 201 is in operation and there is an indoor unit 30 that is stopped, the operation is stopped in the room. The indoor expansion valve 304 of the machine 30 is opened and controlled, and the indoor expansion valve 304 of the indoor unit 30 during operation is closed and controlled to execute the sticking prevention operation for the opening / closing devices 101 and 102 of the indoor unit 30 during operation.
As a result, it is easy to increase the flow rate of the refrigerant in the indoor unit 30 that is stopped, and it is easy 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 during operation can be opened / closed in a state where they are not easily impacted by the flow of the refrigerant. Further, since the refrigerant can be circulated by using the indoor unit 30 which is stopped, the excessive pressure rise of the refrigerant circuit can be suppressed even if the switching devices 101 and 102 are opened and closed.

Further, in the present embodiment, when the control unit 100 executes the sticking prevention operation, when the compressor 201 is in operation and there are a plurality of indoor units 30 in operation, the control unit 100 operates as a "starter". The indoor expansion valve 304 of the indoor unit 30 inside is closed and controlled to execute the sticking prevention operation for the opening / closing devices 101 and 102 of the indoor unit 30 during the "starting" operation. Then, after that, the indoor expansion valve 304 of the indoor unit 30 during the "late" operation is closed and controlled, and the sticking prevention operation is executed for the opening / closing devices 101 and 102 of the indoor unit 30 during the "late" operation.
As a result, when the sticking prevention operation is executed, when the compressor 201 is in operation and there are a plurality of indoor units 30 in operation, the indoor unit 30 in operation of the "starter" and the indoor unit 30 in operation and the "later" Is divided into the indoor units 30 that are in operation, and the sticking prevention operation is executed. Therefore, when the sticking prevention operation is executed for the opening / closing devices 101 and 102 of the indoor unit 30 in operation of one of the "starter" and the "late", the indoor unit in the other of the "starter" and "late" is in operation. Since the refrigerant can be circulated by using 30, the excessive pressure rise of the refrigerant circuit can be suppressed.

Further, in the present embodiment, when the control unit 100 executes the sticking prevention operation, the control unit 100 executes the sticking prevention operation for the opening / closing devices 101 and 102 of the indoor unit 30 which is stopped.
As a result, 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 unit that are stopped.

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

FIG. 5 is a flowchart showing a transition determination operation for abnormality detection of the air conditioner 1 of the first embodiment. FIG. 6 is a flowchart showing an abnormality detection operation of the switchgear of the air conditioner 1. FIG. 7 is a flowchart showing the rest of FIG. The operations of FIGS. 5 to 7 are executed by the control unit 100 controlling each unit of the air conditioner 1.

As shown in FIG. 5, when the control unit 100 starts the process of the transition determination operation of the abnormality detection, the control unit 100 starts the measurement of the second predetermined time (step ST101). The second predetermined time is the shortest time interval for executing the abnormality detection operation. As a result, it is possible to suppress excessive abnormality detection operation of the switchgear. That is, it is possible to prevent the first switchgear 101 and the second switchgear 102 from being excessively opened and closed to wear the switchgear 101 and 102. In the present embodiment, the second predetermined time is set to one month as an example.

The control unit 100 determines whether or not there is an instruction for lowering the operating frequency of the compressor 201 (step ST102).
The control unit 100 executes the process of step ST102 when there is no instruction for lowering control of the operating frequency of the compressor 201 (step ST102; NO).
When the control unit 100 is instructed to control the lowering of the operating frequency of the compressor 201 (step ST102; YES), the control unit 100 determines whether or not the operating frequency of the compressor 201 is equal to or lower than a predetermined value (step ST103). The predetermined value of step ST103 is set to an operating frequency at which the flow rate of the refrigerant is small and the switchgear 101 and 102 are less likely to be impacted by the flow of the refrigerant when the switchgear 101 and 102 are opened and closed.

When the control unit 100 determines that the operating frequency of the compressor 201 is not equal to or lower than a predetermined value (step ST103; NO), the control unit 100 executes the process of step ST102.
When the control unit 100 determines that the operating frequency of the compressor 201 is equal to or lower than a predetermined value (step ST103; YES), the control unit 100 determines whether or not the operating 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), the control unit 100 stops the operation of the air conditioner 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 or not the second predetermined time has elapsed (step ST105). As a result, it is determined whether or not the second predetermined time has elapsed in a state where the flow rate of the refrigerant is low.
When it is determined that the second predetermined time has not elapsed (step ST105; NO), the control unit 100 executes the process of step ST102.
When it is determined that the second predetermined time has elapsed (step ST105; YES), the control unit 100 executes the abnormality detection operation of the switchgear shown in FIGS. 6 and 7 (step ST106).
When the abnormality detection operation of the switchgear 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 switchgear is executed every 30a, 30b, and 30c of the indoor units. In the present embodiment, the flowchart of the abnormality detection operation of the switchgear 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 switchgear corresponds to an example of abnormality determination control of the switchgear.
As shown in FIG. 6, when the control unit 100 starts the processing of the abnormality detection operation of the switchgear, 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 which of the first switchgear 101 and the second switchgear 102 is upstream in the refrigerant flow direction is determined.

When the control unit 100 determines that the cooling operation mode is set (step ST110; YES), the control unit 100 closes and controls the indoor expansion valve 304 to throttle (step ST111). By reducing the flow rate of the refrigerant by reducing the indoor expansion valve 304 and then closing the second switchgear 102 on the downstream side, the impact on the second switchgear 102 that is closed can be suppressed.
The control unit 100 opens the first switchgear 101 corresponding to the upstream side and closes the second switchgear 102 corresponding to the downstream side (step ST112). As a result, when the second switchgear 102 functions normally, the second switchgear 102 is closed, so that the refrigerant is shut off. Therefore, the refrigerant stays in the indoor heat exchanger 301, and the indoor heat exchange 301 does not exchange heat. Therefore, the temperature difference between the refrigerant of the liquid side pipe 13 on the upstream side of the indoor heat exchange 301 and the refrigerant of 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 makes it easier for the refrigerant to flow into the indoor heat exchanger 301 when there is an abnormality in the second switchgear 102.
The control unit 100 determines whether or not the third predetermined time has elapsed (step ST114). The third predetermined time of step ST114 is set to a time during which the refrigerant staying in the indoor heat exchanger 301 does not exchange heat with the indoor air. In the present embodiment, 4 minutes is set as an example of the third predetermined time.

The control unit 100 determines whether or not the refrigerant temperature of the liquid side pipe 13 of the indoor heat exchanger 301 and the refrigerant temperature of the gas side pipe 14 are equal to or less than a predetermined value (step ST115). In the present embodiment, the difference value between the detection temperature of the first temperature sensor 305 provided in the liquid side pipe 13 and the detection temperature of the second temperature sensor 306 provided in the gas side pipe 14 is calculated. Then, it is determined whether or not the difference value of the detected temperature is equal to or less than a minute predetermined value.
Here, when the second switchgear 102 operates normally, the flow of the refrigerant is cut off and the refrigerant stays in the indoor heat exchange 301. Therefore, in the indoor heat exchanger 301, heat exchange between the refrigerant and the indoor air is not performed, 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, when the second switchgear 102 is abnormal, the refrigerant continues to flow through the indoor heat exchange 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 opening / closing device 102, whether the refrigerant temperature of the liquid side pipe 11 of the indoor heat exchanger 301 and the refrigerant temperature of the gas side pipe 12 are equal to or less than a predetermined value. Judge whether or not.

When the control unit 100 determines that the refrigerant temperature of the liquid side pipe 13 of the indoor heat exchanger 301 and the refrigerant temperature of the gas side pipe 14 are equal to or less than a predetermined value (step ST115; YES), the first opening / closing device corresponding to the upstream side. The 101 is closed and the second opening / closing device 102 corresponding to the downstream side is opened (step ST116).
The control unit 100 determines whether or not the third predetermined time has elapsed (step ST117). Step ST117 is the same as step ST114.
The control unit 100 determines whether or not the refrigerant temperature of the liquid side pipe 13 of the indoor heat exchanger 301 and the refrigerant temperature of the gas side pipe 14 are equal to or less than a predetermined value (step ST118). Step ST118 is the same as step ST115.

When the control unit 100 determines that the refrigerant temperature of the liquid side pipe 13 of the indoor heat exchanger 301 and the refrigerant temperature of the gas side pipe 14 are equal to or less than a predetermined value (step ST118; YES), the control unit 100 opens the first opening / closing device 101. (Step ST119). As a result, the first switchgear 101 is returned 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 of the liquid side pipe 13 of the indoor heat exchanger 301 and the refrigerant temperature of the gas side pipe 14 are not equal to or lower than a predetermined value (step ST115; NO), an abnormality is found in the second switchgear 102. It is determined that there is, and an abnormality of the second switchgear 102 is notified (step ST122). As the means for notifying the abnormality of the second switchgear 102, the operation screen 100b may indicate that the second switchgear 102 is abnormal, or a sound source as an example of the not shown not shown may be controlled to sound a notification sound. It can be configured.
The control unit 100 fully closes the indoor expansion valve 304 (step ST121). As a result, the flow of the refrigerant is blocked.
Then, the control unit 100 ends the abnormality detection operation of the switchgear.

When the control unit 100 determines that the refrigerant temperature of the liquid side pipe 13 of the indoor heat exchanger 301 and the refrigerant temperature of the gas side pipe 14 are not equal to or lower than a predetermined value (step ST118; NO), an abnormality is found in the first switchgear 101. It is determined that there is, and an abnormality of the first switchgear 101 is notified (step ST120).
The control unit 100 fully closes the indoor expansion valve 304 (step ST121), and ends the abnormality detection operation of the switchgear.

When the control unit 100 is not in the cooling operation mode, that is, in the heating operation mode (step ST110; NO), the indoor expansion valve 304 is closed and throttled (step ST130 in FIG. 7). The flow rate of the refrigerant is reduced by throttle the indoor expansion valve 304.
The control unit 100 opens the second switchgear 102 corresponding to the upstream side and closes the first switchgear 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 switchgear on the upstream side and the switchgear on the downstream side are opposite to the switchgear of steps ST112 to ST121 shown in FIG. , Detailed description will be omitted.

Here, in the conventional configuration described in Patent Document 1, since the switchgear is not closed unless a refrigerant leak occurs, the switchgear may be stuck, and the reliability of the switchgear is lowered. Had the task of doing.

On the other hand, in the present embodiment, the refrigerant is normally released when the switchgear 101 and 102 are closed by the processes of steps ST112 to ST115, steps ST116 to ST118, steps ST131 to ST134, and steps ST135 to ST137. It is determined whether or not it is blocked. Therefore, when the switchgear 101, 102 is determined to be abnormal, the switchgear 101, 102 can be repaired or replaced, so that the reliability of the switchgear 101, 102 is improved.

As described above, the air conditioner 1 of the present embodiment is the liquid side that connects the outdoor unit 20 having the compressor 201, the indoor unit 30 having the indoor heat exchanger 301, and the outdoor unit 20 and the indoor unit 30. The first opening / closing device 101 that opens / closes the pipes 11 and 13 and the gas side pipes 12 and 14, the liquid side pipe 13 connected to the indoor unit 30, and the second opening / closing the gas side pipe 13 connected to the indoor unit 30. It includes an opening / closing device 102, an indoor expansion valve 304 provided between the first opening / closing device 101 and the indoor heat exchanger 301 to control the flow rate of the refrigerant, and a control unit 100. In the air conditioner 1, the control unit 100 controls at least one of the first switchgear 101 and the second switchgear 102 to be closed while the indoor expansion valve 304 is open, and the first switchgear 101 and the second switchgear 102 are closed. An abnormality detection operation for determining an abnormal state of the switchgear 101, 102 whose closing control is controlled among the devices 102 is executed.
Thereby, the abnormal state of the first switchgear 101 and the second switchgear 102 can be determined depending on whether or not the refrigerant flowing in the indoor unit 30 is blocked by the switchgear 101 and 102 controlled to be closed.

In the present embodiment, the air conditioner 1 includes a first temperature sensor 305 arranged in the liquid side pipe 13 between the first opening / closing device 101 and the indoor heat exchanger 301 to detect the refrigerant temperature, and the second opening / closing device 102. A second temperature sensor 306, which is arranged in the gas side pipe 14 between the indoor heat exchangers 301 and detects the refrigerant temperature, is provided. Then, in the abnormality detection operation, the control unit 100 of the air conditioner 1 controls to open one of the first switchgear 101 and the second switchgear 102, and the other switchgear 102, 101. Is closed, and when the difference value between the detected temperatures of the first temperature sensor 305 and the second temperature sensor 306 is higher than the predetermined temperature, it is determined that the other switchgear 102, 101 is in an abnormal state.
Thereby, the refrigerant temperature between the first switchgear 101 and the indoor heat exchanger 301 and the refrigerant temperature between the second switchgear 102 and the indoor heat exchanger 301 can be detected. Therefore, it is possible to determine whether or not the refrigerant is shut off based on the temperature difference between the liquid side and the gas side of the indoor heat exchanger 301, and determine the abnormal state of the switchgear 101 and 102.

Further, in the present embodiment, the control unit 100 throttles the indoor expansion valve 304 in the abnormality detection operation, and the switchgear 101 on the upstream side in the flow direction of the refrigerant in the first switchgear 101 and the second switchgear 102, The opening control of 102 and the closing control of the opening / closing devices 102 and 101 on the downstream side are performed to determine whether or not the opening / closing devices 102 and 101 on the downstream side are in an abnormal state.
As a result, the indoor expansion valve 304 closes and controls the opening / closing devices 102 and 101 on the downstream side in the refrigerant flow direction in a state where the flow rate of the refrigerant flowing to the opening / closing devices 102 and 101 on the downstream side in the refrigerant flow direction is reduced. Therefore, the impact that the switchgear 102, 101 receives from the refrigerant can be suppressed.

Further, in the present embodiment, the control unit 100 opens and controls the downstream opening / closing devices 102 and 101 after determining whether or not the downstream opening / closing devices 102 and 101 are in an abnormal state in the abnormality detection operation. At the same time, the opening / closing devices 101 and 102 on the upstream side are controlled to be closed, and it is determined whether or not the opening / closing devices 101 and 102 on the upstream side are in an abnormal state.
As a result, it is possible to determine the abnormality of the switchgear 102, 101 on the upstream side in the flow direction of the refrigerant.

Further, in the present embodiment, when the control unit 100 determines that the switchgear 101, 102 is in the abnormal state in the abnormality detection operation, the control unit 100 notifies that the switchgear 101, 102 is in the abnormal state.
This makes it easier to recognize that the switchgear 101, 102 is in an abnormal state.

Further, in the present embodiment, the control unit 100 closes and controls the indoor expansion valve 304 when it is determined in the abnormality detection operation that at least one of the first switchgear 101 and the second switchgear 102 is in an abnormal state. ..
As a result, when the switchgear 101, 102 is in an abnormal state, the indoor expansion valve 304 can be closed and controlled to regulate the flow of the refrigerant.

Further, in the present embodiment, when the operating frequency of the compressor 201 is equal to or less than a predetermined value and the second predetermined time has elapsed after executing the abnormality detection operation, the control unit 100 again has an abnormality. Execute the detection operation.
As a result, when the impact received from the flow of the refrigerant is small, the switchgear 101 and 102 can be opened and closed to execute the abnormality detection operation. In addition, it is possible to suppress the execution of an excessive abnormality detection operation.

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

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

The control unit 100 lower-controls the operating frequency of the compressor 201 (step ST203). The operation frequency lowering control 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 is detected to the operating capacity of the indoor unit 30. Specifically, for example, when the operating frequency before detection is 60 Hz, the operating capacity of the indoor unit 30 in which leakage is detected is 5 HP (horsepower), and the operating capacity of all indoor units 30 is 15 HP. , 60Hz × (5HP / 15HP) = 20Hz, the operation frequency is lowered.

The control unit 100 fully closes the indoor expansion valve 304 in the indoor unit 30 in which the leak is detected (step ST204). Thereby, the flow of the refrigerant can be regulated.
The control unit 100 closes the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 in which the leak is detected (step ST205).
The control unit 100 determines whether or not the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 in which leakage has not been detected are in the open state (step ST206).

When the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 in which leakage has not been detected are in the open state (step ST206; YES), the control unit 100 continues the operation (step ST207), and the refrigerant Ends the processing of the leak detection operation.
When the first switchgear 101 and the second switchgear 102 corresponding to the indoor unit 30 in which leakage has not been detected are not in the open state (step ST206; NO), the control unit 100 stops the operation (step ST208), and the refrigerant Ends the processing of the leak detection operation.

Here, in the conventional configuration described in Patent Document 1, the switchgear is closed when a refrigerant leak occurs. However, when a refrigerant leak occurs, simply closing the switchgear in the closed state may cause the shock of the refrigerant flowing in the refrigerant circuit to be transmitted to the closed switchgear, resulting in damage to the switchgear. There is. Therefore, in the conventional configuration, there is a problem that the operation reliability of the switchgear is lowered.

On the other hand, in the present embodiment, the drive frequency is reduced by step ST203 to reduce the flow rate of the refrigerant, and the indoor expansion valve 304 is closed by step ST204 to regulate the flow of the refrigerant, and then the first step ST205 is performed. The switchgear 101 and the second switchgear 102 are in the closed state. Therefore, the impact of the refrigerant flowing in the refrigerant circuit is prevented from being transmitted to the switchgear 101 and 102 in the closed state. Therefore, the risk of damage to the switchgear 101 and 102 can be reduced, and the operational reliability of the switchgear 101 and 102 can be improved.

The above-mentioned step ST204 is preferably present, but may be omitted. That is, the control unit 100 may shift to step ST205 after executing step ST203.

As described above, the air conditioner 1 of the present embodiment has the refrigerant pipes 11, 12, 13, 14 connecting the outdoor unit 20 having the compressor 201, the indoor unit 30, the outdoor unit 20 and the indoor unit 30. It also includes opening / closing devices 101 and 102 for opening and closing the refrigerant pipes 13 and 14, a refrigerant leakage sensor 307 for detecting the refrigerant concentration, and a control unit 100. Then, when the detection concentration of the refrigerant leakage sensor 307 is equal to or higher than a predetermined value, the control unit 100 controls the operating frequency of the compressor 201 to be equal to or lower than the predetermined value, and then closes the switchgear 101 and 102.
As a result, after the refrigerant leakage is detected, the operating frequency of the compressor 201 is lowered and the switching devices 101 and 102 are closed and controlled in a state where the flow rate of the refrigerant flowing in the refrigerant circuit is small, so that the refrigerant transmitted to the switching devices 101 and 102 is transmitted. Impact is suppressed. Therefore, the risk of damage to the switchgear 101 and 102 can be reduced, and the operational reliability of the switchgear 101 and 102 can be improved.

In the present embodiment, when the detection concentration of the refrigerant leakage sensor 307 is equal to or higher than a predetermined value, the control unit 100 closes the indoor expansion valve 304 and then closes the opening / closing devices 101 and 102.
As a result, after the refrigerant leakage is detected, the indoor expansion valve 304 is closed and controlled, and the switchgear 101 and 102 are closed and controlled while the flow rate of the refrigerant flowing in the refrigerant circuit is small, so that the impact of the refrigerant transmitted to the switchgear is suppressed. NS. Therefore, the risk of damage to the switchgear 101 and 102 can be reduced, and the operational reliability of the switchgear 101 and 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 of the second embodiment. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.
The control unit 100 of the air conditioner 1 of the second embodiment is different from the first embodiment in that it controls the flowchart shown in FIG. 9 instead of controlling the flowchart shown in FIG.
As shown in FIG. 9, when the process of the transition determination operation for sticking prevention is started, the control unit 100 determines whether or not the operating frequency of the compressor 201 is equal to or less than a predetermined value (step ST61). The predetermined value of step ST61 is set to a frequency at which the flow rate of the refrigerant is small and the flow of the refrigerant does not easily give an impact to the switchgear 101 and 102.

When the control unit 100 determines that the operating frequency of the compressor 201 is not equal to or lower than a predetermined value (step ST61; NO), the control unit 100 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 a 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 the present 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.
As a result, the switchgear 101 and 102 can be easily opened and closed while the flow rate of the refrigerant is low, and the switchgear 101 and 102 are less likely to be impacted by the flow of the refrigerant.

[3. Third Embodiment]
FIG. 10 is a flowchart showing a transition determination operation for preventing sticking of the air conditioner 1 of the third embodiment. In the third embodiment, the components common to the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted.
The operation unit 100a of the air conditioner 1 of the third embodiment is configured to input the permission to shift 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 conditioner 1 of the third embodiment is different from the first embodiment in that it controls the flowchart shown in FIG. 10 instead of controlling the flowchart shown in FIG.
As shown in FIG. 10, the control unit 100 detects the presence / absence of an input of the operation unit 100a and determines whether or not there is an input of 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 the present embodiment, the operation unit 100a for inputting the permission to shift to the sticking prevention operation is provided, and the control unit 100 executes the sticking prevention operation when the input by the operation unit 100a is detected.
As a result, the permission to shift to the sticking prevention operation can be input to the control unit 100. Therefore, the control unit 100 can be allowed to shift to the sticking prevention operation at an arbitrary timing.

[4. Fourth Embodiment]
FIG. 11 is a flowchart showing a transition determination operation for abnormality detection of the air conditioner 1 of the fourth embodiment. In the fourth embodiment, the components common to the first to third embodiments are designated by the same reference numerals, and the description thereof will be omitted.
The operation unit 100a of the air conditioner 1 of the fourth embodiment is configured to input to the control unit 100 permission to shift to the abnormality detection operation of the switchgear. The operation unit 100a corresponds to an example of the second input unit.

The control unit 100 of the air conditioner 1 of the fourth embodiment is different from the first embodiment in that it controls the flowchart shown in FIG. 11 instead of controlling the flowchart shown in FIG.
As shown in FIG. 11, the control unit 100 detects the presence / absence of an input of the operation unit 100a, and determines whether or not there is an input of permission to shift to the abnormality detection operation of the switchgear (step ST181).

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

In the present embodiment, the operation unit 101a for inputting the permission to shift to the abnormality detection operation of the switchgear is provided, and the control unit 101 executes the abnormality detection operation of the switchgear when the input by the operation unit 101a is detected.
As a result, the control unit 101 can be allowed to shift to the abnormality detection operation of the switchgear at an arbitrary timing.

[5. Other embodiments]
Although the present invention has been described based on the embodiments, the present invention is not limited to the present embodiment. Since it merely illustrates one embodiment of the present invention, it can be arbitrarily modified and applied without departing from the spirit of the present invention.

The sticking prevention operation is executed based on the first predetermined time in the first embodiment, is executed based on the operating frequency of the compressor 201 in the second embodiment, and is based on the input of the operation unit 100a in the third embodiment. The configuration to be executed was explained. However, for example, the sticking prevention operation may be executed based on the first predetermined time and may be executed 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 be executed based on the input of the operation 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 separately. The control unit 100 may be configured to process in parallel.

The abnormality detection operation of the switchgear is executed based on the second predetermined time and the operating frequency of the compressor 201 in the first to third embodiments, and is executed based on the input of the operation unit 100a in the fourth embodiment. The configuration was explained. However, the abnormality detection operation of the switchgear may be executed based on the second predetermined time and the operating frequency of the compressor 201, and may be executed based on the input of 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 separately, and the control unit 100 processes them in parallel. It may be configured.

In the above embodiment, as an example, an air conditioner 1 having a package air conditioner (PAC) configuration including one outdoor unit 20 and three indoor units 30 is shown, but the present invention is not limited thereto. .. For example, a room air conditioner (RAC) having one outdoor unit 20 and one indoor unit 30, a package air conditioner (PAC) in which a plurality of indoor units are connected to a plurality of outdoor units, and a multi air conditioner for buildings (multi air conditioner for buildings). It is also applicable to VRF) configurations.

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 the leaked refrigerant even when the refrigerant leaks.

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 switchgear 102a, 102b, 102c Second switchgear 201 Compressor 301a, 301b, 301c Indoor heat exchanger (utility side heat exchanger)
302a, 302b, 302c Indoor fan 304a, 304b, 304b Indoor expansion valve (squeezing device)
305a, 305b, 305c 1st temperature sensor 306a, 306b, 306c 2nd temperature sensor 307a, 307b, 307c Refrigerant leakage sensor

Claims (22)

An outdoor unit with a compressor and
An indoor unit with a heat exchanger on the user side and
Refrigerant piping connecting the outdoor unit and the indoor unit,
A switchgear arranged in the refrigerant pipe and
Control unit and
In an air conditioner equipped with
The control unit is an air conditioner that executes a sticking prevention operation that opens and closes the switchgear when the refrigerant does not leak. The refrigerant pipe has a liquid side pipe and a gas side pipe.
The switchgear is characterized by having a first switchgear that opens and closes the liquid side pipe connected to the indoor unit and a second switchgear that opens and closes the gas side pipe connected to the indoor unit. The air conditioner according to claim 1. The air conditioner according to claim 2, wherein the control unit executes the sticking prevention operation for opening and closing the first switchgear and the second switchgear. The air conditioner according to claim 3, wherein the liquid side pipe is provided with a throttle device for controlling the flow rate of the refrigerant between the first switchgear and the user side heat exchanger. Equipped with a plurality of the indoor units arranged in parallel,
The first switchgear and the second switchgear are provided for each indoor unit.
The air conditioner according to claim 4, wherein the throttle device is provided for each indoor unit. A claim, wherein the control unit executes the sticking prevention operation for the opening / closing devices of all the indoor units when the compressor is stopped when the sticking prevention operation is executed. 5. The air conditioner according to 5. When the control unit executes the sticking prevention operation, if the compressor is in operation and there is an indoor unit that is stopped, the throttle device of the indoor unit that is stopped is operated. 5. The air conditioner described in. When the control unit executes the sticking prevention operation, if the compressor is in operation and there are a plurality of the indoor units in operation, the control unit is the indoor unit in the first operation. After the throttle device is closed and controlled to execute the sticking prevention operation for the switchgear of the indoor unit during the first operation, the throttle device of the indoor unit during the second operation is closed and controlled. The air conditioner according to any one of claims 5 to 7, wherein the switchgear of the indoor unit during the second operation is subjected to the sticking prevention operation. The air conditioner according to claim 7 or 8, wherein the control unit executes the sticking prevention operation with respect to the switchgear of the indoor unit that is stopped when the sticking prevention operation is executed. .. The air conditioning according to any one of claims 1 to 9, wherein the control unit executes the sticking prevention operation again after a lapse of a first predetermined time. Device. The air conditioner according to any one of claims 1 to 10, wherein the control unit executes the sticking prevention operation when the operating frequency of the compressor is equal to or less than a predetermined value. It is equipped with an input unit for inputting permission to shift to the sticking prevention operation.
The air conditioner according to any one of claims 1 to 11, wherein the control unit executes the sticking prevention operation when the input by the input unit is detected. With the throttle device open, the control unit closes and controls at least one of the first switchgear and the second switchgear, and closes and controls the first switchgear and the second switchgear. The air conditioner according to claim 4 or 5, wherein an abnormality determination control for determining an abnormal state of the apparatus is executed. A first temperature sensor arranged in the liquid side pipe between the first switchgear and the utilization side heat exchanger to detect the refrigerant temperature, and
A second temperature sensor, which is arranged in the gas side pipe between the second switchgear and the utilization side heat exchanger and detects the refrigerant temperature, is provided.
In the abnormality determination control, the control unit opens and controls one of the first switchgear and the second switchgear and closes and controls the other switchgear, and the first temperature sensor and the second switchgear. The air conditioner according to claim 13, wherein when the difference value of the detection temperature of the second temperature sensor is higher than a predetermined temperature, it is determined that the other switchgear is in an abnormal state. In the abnormality determination control, the control unit throttles the throttle device, opens and controls the switchgear on the upstream side in the flow direction of the refrigerant in the first switchgear and the second switchgear, and opens and closes on the downstream side. The air conditioner according to claim 14, wherein the device is closed and controlled to determine whether or not the switchgear on the downstream side is in an abnormal state. In the abnormality determination control, the control unit determines whether or not the downstream opening / closing device is in an abnormal state, and then controls the opening / closing of the downstream opening / closing device and closes the upstream opening / closing device. The air conditioner according to claim 15, further comprising determining whether or not the switchgear on the upstream side is in an abnormal state. When the switchgear is determined to be 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 13 to 16, wherein the air conditioner is characterized by the above. The control unit executes the abnormality determination control again when the operating frequency of the compressor is equal to or less than a predetermined value and the second predetermined time has elapsed after executing the abnormality determination control. The air conditioner according to any one of claims 13 to 17, wherein the air conditioner. A second input unit for inputting permission to shift to the abnormality determination control is provided.
The air conditioner according to any one of claims 13 to 18, wherein the control unit executes the abnormality determination control when the input by the second input unit is detected. The claim is characterized in that the control unit closes and controls the diaphragm device when it is determined in the abnormality determination control that at least one of the first switchgear and the second switchgear is in an abnormal state. The air conditioner according to any one of 13 to 19. The indoor unit includes a refrigerant leakage sensor that detects the refrigerant concentration.
The control unit is characterized in that, when the detection concentration of the refrigerant leakage sensor is equal to or higher than a predetermined value, the operating frequency of the compressor is controlled to be equal to or lower than a predetermined value, and then the switchgear is closed. The air conditioner according to 4 or 5. The air conditioner according to claim 21, wherein when the detection concentration of the refrigerant leakage sensor is equal to or higher than a predetermined value, the control unit closes the throttle device and then closes the switchgear. ..

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