Patent Description:
Conventionally known air conditioning apparatuses include an outdoor unit, an indoor unit, and a refrigerant pipe which constitute a refrigeration cycle, and the indoor unit is provided with a refrigerant leakage sensor which detects leakage of a refrigerant flowing through the refrigeration cycle, the leakage being caused by, for example, breakage of the refrigerant pipe.

An air conditioning apparatus known as such an air conditioning apparatus is capable of determining whether detection of the refrigerant leakage sensor is erroneous detection to prevent the refrigerant leakage sensor from erroneously detecting, as refrigerant leakage, an object other than the refrigerant, such as smoke generated in a space where the indoor unit is installed (e.g., refer to <CIT>).

However, in the conventional air conditioning apparatus, after the refrigerant leakage sensor detects the refrigerant, it is determined whether the detection of the refrigeration leakage sensor is erroneous detection without closing the refrigerant pipe through which the refrigerant flows. Thus, when the detection of the refrigerant leakage sensor is not erroneous detection, the refrigerant may further leak during the determination as to whether the detection of the refrigerant leakage sensor is erroneous detection.

It is an object of the present invention to provide an air conditioning apparatus capable of determining whether detection of the refrigerant leakage sensor is erroneous detection while more reliably suppressing refrigerant leakage.

<CIT> describes a refrigeration apparatus that includes a compressor; a heat source-side expansion valve to be controlled to have a minimum opening degree and brought into a closed state in which the heat source-side expansion valve maximizes prevention of a flow of a refrigerant toward a usage-side refrigerant circuit; a fusible plug; a controller; and a refrigerant leak sensor configured to detect a refrigerant leak at the usage-side refrigerant circuit. An erroneous detection determination unit determines whether the refrigerant leak sensor erroneously detects a refrigerant leak when the refrigerant leak sensor detects the refrigerant leak.

The present invention provides an air conditioning apparatus as defined in appended claim <NUM>. The air conditioning apparatus includes: an outdoor unit; an indoor unit including an air blowing fan, an air outlet for blowing out air fed by the air blowing fan, an air direction plate capable of opening and closing the air outlet, and a refrigerant leakage sensor configured to detect a refrigerant; a refrigerant pipe connecting the outdoor unit and the indoor unit; an opening/closing device configured to open and close the refrigerant pipe; and a control unit configured to close the opening/closing device and drive the air blowing fan for a predetermined time when the refrigerant leakage sensor detects a refrigerant concentration higher than a predetermined value, then stop the air blowing fan and close the air direction plate when the refrigerant leakage sensor detects a refrigerant concentration higher than the predetermined value, then open the air direction plate when a refrigerant concentration detected by the refrigerant leakage sensor remains substantially equal to or decreases from the concentration previously detected, and then determine that detection of the refrigerant leakage sensor is erroneous detection when a refrigerant concentration detected by the refrigerant leakage sensor becomes higher than the concentration previously detected.

With this configuration, the control unit determines whether there is refrigerant leakage in a state where the opening/closing device configured to open and close the refrigerant pipe is closed. Thus, the control unit can determine whether detection of the refrigerant leakage sensor is erroneous detection while more reliably suppressing refrigerant leakage.

According to the present invention, it is possible to determine whether detection of the refrigerant leakage sensor is erroneous detection while more reliably suppressing refrigerant leakage.

Among others, the air conditioning apparatus of the present invention includes: an outdoor unit; an indoor unit including an air blowing fan, an air outlet for blowing out air fed by the air blowing fan, an air direction plate capable of opening and closing the air outlet, and a refrigerant leakage sensor configured to detect a refrigerant; a refrigerant pipe connecting the outdoor unit and the indoor unit; an opening/closing device configured to open and close the refrigerant pipe; and a control unit.

The control unit is configured to close the opening/closing device and drive the air blowing fan for a predetermined time when the refrigerant leakage sensor detects a refrigerant concentration higher than the predetermined value, then stop the air blowing fan and close the air direction plate when the refrigerant leakage sensor detects a refrigerant concentration higher than the predetermined value, then open the air direction plate when a refrigerant concentration detected by the refrigerant leakage sensor remains substantially equal to or decreases from the concentration previously detected, and then determine that detection of the refrigerant leakage sensor is erroneous detection when a refrigerant concentration detected by the refrigerant leakage sensor becomes higher than the concentration previously detected.

With this configuration, the control unit determines whether there is refrigerant leakage in a state where the opening/closing device configured to open and close the refrigerant pipe is closed. Thus, the control unit can determine whether detection of the refrigerant leakage sensor is erroneous detection while more reliably suppressing refrigerant leakage. Moreover, the control unit acquires the refrigerant concentration in a case where the air direction plate is open and the refrigerant concentration in a case where the air direction plate is closed and determines whether a detection signal of the refrigerant leakage sensor is generated by erroneous detection.

Thus, for example, even in the space to be air-conditioned constantly filled with a large amount of smoke or gas, such as a smoking area, the control unit can achieve erroneous detection determination for the refrigerant leakage sensor with higher accuracy.

In an embodiment, the control unit closes the opening/closing device and drives the air blowing fan for a predetermined time when the refrigerant leakage sensor detects a refrigerant concentration higher than the predetermined value, then opens the opening/closing device and stops the air blowing fan when the refrigerant leakage sensor detects a refrigerant concentration equal to or lower than the predetermined value, and then determines that detection of the refrigerant leakage sensor is erroneous detection when a refrigerant concentration detected by the refrigerant leakage sensor remains substantially equal to or decreases from the concentration previously detected.

With this configuration, when, for example, smoke temporarily builds up inside the indoor unit, the air conditioning apparatus feeds the smoke out by using the air blowing fan to remove the smoke, thereby preventing erroneous detection.

This enables the control unit to determine that the detection signal of the refrigerant leakage sensor is generated by erroneous detection when determining that the refrigerant concentration has temporarily increased due to, for example, spray gas or cigarette smoke.

Hereinbelow, an embodiment of the present invention will be described with reference to the drawings.

<FIG> is a diagram showing a schematic configuration of a refrigerant circuit of an air conditioning apparatus <NUM> according to the embodiment of the present invention. <FIG> is a block diagram schematically showing each part of the air conditioning apparatus <NUM>. For convenience of description, <FIG> shows only an indoor unit 30a as an indoor unit <NUM>, a first opening/closing device 101a as a first opening/closing device <NUM>, and a second opening/closing device 102a as a second opening/closing device <NUM>.

The air conditioning apparatus <NUM> includes an outdoor unit <NUM>, and a plurality of indoor units 30a, 30b, 30c. The indoor units 30a, 30b, 30c are connected in parallel to the outdoor unit <NUM> through a liquid-side pipe <NUM> and a gas-side pipe <NUM>. The liquid-side pipe <NUM> includes liquid-side pipes 13a, 13b, 13c which branch from the liquid-side pipe <NUM> and are respectively connected to the indoor units 30a, 30b, 30c. The gas-side pipe <NUM> includes gas-side pipes 14a, 14b, 14c which branch from the gas-side pipe <NUM> and are respectively connected to the indoor units 30a, 30b, 30c.

The outdoor unit <NUM>, the indoor units 30a, 30b, 30c, the liquid-side pipe <NUM>, and the gas-side pipe <NUM> constitute a refrigeration cycle.

The air conditioning apparatus <NUM> circulates, between the outdoor unit <NUM> and the indoor units 30a, 30b, 30c, a refrigerant compressed by the outdoor unit <NUM>, thereby air-conditioning a space to be air-conditioned where the indoor units 30a, 30b, 30c are installed.

The indoor units 30a, 30b, 30c are configured similarly to each other. Thus, corresponding elements between the indoor units 30a, 30b, 30c are designated with the same reference numeral and distinguished from each other with indexes a, b, c. When it is not necessary to particularly distinguish the corresponding elements from each other, only the reference numeral may be used, and the indexes a, b, c may be omitted.

The outdoor unit <NUM> includes a compressor <NUM> which compresses the refrigerant, an outdoor heat exchanger <NUM> which performs heat exchange of the refrigerant, an outdoor fan <NUM>, an expansion valve <NUM>, and a switching valve <NUM>.

The compressor <NUM> sucks the refrigerant from a suction pipe <NUM>, compresses the sucked refrigerant, and discharges the compressed refrigerant.

The outdoor heat exchanger <NUM> exchanges heat between the refrigerant and outdoor air in the outdoor unit <NUM>. The outdoor heat exchanger <NUM> functions as a condenser in a cooling operation mode and functions as an evaporator in a heating operation mode.

The outdoor fan <NUM> blows air to the outdoor heat exchanger <NUM>.

The expansion valve <NUM> decompresses and expands the high-pressure refrigerant. The expansion valve <NUM> has an adjustable opening degree. The opening degree of the expansion valve <NUM> is controlled by a control unit <NUM>. The expansion valve <NUM> may be a valve that has an adjustable opening degree and is capable of blocking the refrigerant.

The switching valve <NUM> includes, for example, a four-way valve. The switching valve <NUM> switches the flow of the refrigerant discharged from the compressor <NUM> and the refrigerant returning to the compressor <NUM>. The switching valve <NUM> switches between the cooling operation mode and the heating operation mode of the air conditioning apparatus <NUM>.

The indoor unit <NUM> includes an indoor heat exchanger <NUM>, an indoor fan <NUM>, an indoor expansion valve <NUM>, a first temperature sensor <NUM>, a second temperature sensor <NUM>, and a refrigerant leakage sensor <NUM>.

The indoor heat exchanger <NUM> exchanges heat between the refrigerant supplied from the outdoor unit <NUM> through the liquid-side pipe <NUM> or the gas-side pipe <NUM> and indoor air. The indoor heat exchanger <NUM> corresponds to an example of a use-side heat exchanger.

The indoor fan <NUM> functions as an air blowing fan that blows air to the indoor heat exchanger <NUM> to feed air-conditioning air.

The indoor expansion valve <NUM> is disposed on the liquid-side pipe <NUM> between the expansion valve <NUM> and the indoor heat exchanger <NUM>. In the present embodiment, the indoor expansion valve <NUM> is disposed on the liquid-side pipe <NUM> connected to the indoor heat exchanger <NUM>. The indoor expansion valve <NUM> is configured similarly to the expansion valve <NUM>. The indoor expansion valve <NUM> corresponds to an example of a throttle device.

The liquid-side pipe <NUM> connected to the indoor heat exchanger <NUM> is provided with a first temperature sensor <NUM>. In the present embodiment, the first temperature sensor <NUM> is disposed in a connection part where the liquid-side pipe <NUM> is connected to the indoor heat exchanger <NUM>. The first temperature sensor <NUM> detects the temperature of the refrigerant and inputs a detection signal to the control unit <NUM>.

The gas-side pipe <NUM> connected to the indoor heat exchanger <NUM> is provided with a second temperature sensor <NUM>. In the present embodiment, the second temperature sensor <NUM> is disposed in a connection part where the gas-side pipe <NUM> is connected to the indoor heat exchanger <NUM>. The second temperature sensor <NUM> detects the temperature of the refrigerant and inputs a detection signal to the control unit <NUM>.

Examples of the refrigerant used in the air conditioning apparatus <NUM> include various refrigerants. In recent years, refrigerants such as hydrocarbons, ammonia, and R32 are used as so-called CFC substitutes in air conditioning apparatuses. The CFC substitutes include a slightly flammable or flammable CFC substitute. When the slightly flammable or flammable refrigerant leaks, it is required that the amount of refrigerant leakage be reduced so that the refrigerant concentration in the space to be air-conditioned of the indoor unit <NUM> does not reach a lower flammability limit (LFL). In particular, reducing the amount of refrigerant leakage from the space to be air-conditioned or the indoor unit <NUM> installed near the space to be air-conditioned is desired.

The refrigerant leakage sensor <NUM> is disposed near the indoor heat exchanger <NUM>. The refrigerant leakage sensor <NUM> detects a refrigerant concentration and transmits the detected refrigerant concentration as a detection signal to the control unit <NUM>.

The indoor unit <NUM> includes an air outlet <NUM> for blowing out air-conditioning air fed by the indoor fan <NUM>. The air outlet <NUM> is provided with an air direction plate <NUM> which is capable of opening and closing the air outlet <NUM>. The air direction plate <NUM> turns to open or close the air outlet <NUM>. Moreover, the air direction plate <NUM> functions as a member that controls a blow-out direction of the air-conditioning air.

A first opening/closing device <NUM> and a second opening/closing device <NUM> which regulate the flow rate of the refrigerant to the indoor unit <NUM> are disposed on opposite sides of the indoor heat exchanger <NUM> of the indoor unit <NUM>.

The first opening/closing device <NUM> is disposed on the liquid-side pipe <NUM> connected to the indoor heat exchanger <NUM>. The first opening/closing device <NUM> of the present embodiment includes an on-off valve such as a motor-operated valve or an electromagnetic valve. The first opening/closing device <NUM> is switchable between an open state in which the refrigerant circulates therethrough and a closed state in which the flow of the refrigerant is blocked. Opening and closing of the first opening/closing device <NUM> are controllable by the control unit <NUM>. The first opening/closing device <NUM> is configured to automatically become the closed state when power fails.

The first opening/closing device <NUM> may be a valve settable to a state between the open state and the closed state, or the opening degree of the first opening/closing device <NUM> may be controlled by the control unit <NUM>.

The second opening/closing device <NUM> is disposed on the gas-side pipe <NUM> connected to the indoor heat exchanger <NUM>. The second opening/closing device <NUM> is configured similarly to the first opening/closing device <NUM>.

In the cooling operation mode of the air conditioning apparatus <NUM>, the refrigerant flows in a circulation direction F1. The refrigerant flows through the compressor <NUM>, the outdoor heat exchanger <NUM>, the expansion valve <NUM>, the indoor expansion valve <NUM>, the indoor heat exchanger <NUM>, and the switching valve <NUM> in this order and returns to the suction pipe <NUM> from the switching valve <NUM>.

On the other hand, in the heating operation mode of the air conditioning apparatus <NUM>, the refrigerant flows in a circulation direction F2. The refrigerant flows through the compressor <NUM>, the indoor heat exchanger <NUM>, the indoor expansion valve <NUM>, the expansion valve <NUM>, the outdoor heat exchanger <NUM>, and the switching valve <NUM> in this order and returns to the suction pipe <NUM> from the switching valve <NUM>.

As described above, the air conditioning apparatus <NUM> includes the control unit <NUM>. The control unit <NUM> includes a computer including a processor, such as a CPU or an MPU, and a memory device, such as a ROM or a RAM, and controls each part of the air conditioning apparatus <NUM>.

An operation unit 100a which includes a remote controller or an operation panel is connected to the control unit <NUM> through a wire or wirelessly. The operation unit 100a is provided with a display unit 100b. The display unit 100b is configured to display an operation state of the operation unit 100a and an operating state of the air conditioning apparatus <NUM>. The operation unit 100a corresponds to an example of an input unit.

As shown in <FIG>, the control unit <NUM> is connected to the outdoor unit <NUM>, the indoor unit <NUM>, the first opening/closing device <NUM>, and the second opening/closing device <NUM> through a wire or wirelessly. The control unit <NUM> receives, for example, a detection signal transmitted from the refrigerant leakage sensor <NUM> and a signal transmitted from each part of the air conditioning apparatus <NUM> and also transmits a signal to each part of the air conditioning apparatus <NUM>.

The control unit <NUM> controls operation of each part in the refrigeration cycle of the air conditioning apparatus <NUM>.

Specifically, the control unit <NUM> executes control of the operation of the compressor <NUM>, control of the opening degree and opening and closing of the expansion valve <NUM> and the indoor expansion valve <NUM>, control of switching of a flow passage of the switching valve <NUM>, and control of the operation and stop of the outdoor fan <NUM> and the indoor fan <NUM>.

The control unit <NUM> operates the expansion valve <NUM>, the indoor expansion valve <NUM>, and the switching valve <NUM> to switch between the cooling operation mode and the heating operation mode of the air conditioning apparatus <NUM>. Moreover, the control unit <NUM> executes control of the operation frequency, operation, and stop of the compressor <NUM> and control of the outdoor fan <NUM> and the indoor fan <NUM> according to a target temperature set by an operation on the operation unit 100a to air-condition the space to be air-conditioned according to the target temperature.

The control unit <NUM> executes control of opening and closing of the first opening/closing device <NUM> and the second opening/closing device <NUM>.

Moreover, the control unit <NUM> adjusts opening and closing and the opening degree of the air direction plate <NUM>.

The control unit <NUM> receives a detection signal of the refrigerant leakage sensor <NUM> and determines whether there is refrigerant leakage in the indoor unit <NUM>.

The control unit <NUM> of the present embodiment acquires the refrigerant concentration in the indoor unit <NUM> by acquiring the detection signal from the refrigerant leakage sensor <NUM>. Then, the control unit <NUM> determines whether the acquired refrigerant concentration is higher than a predetermined value. When it is determined that the acquired refrigerant concentration is higher than the predetermined value, the control unit <NUM> executes an anti-leakage measure operation.

Specifically, the control unit <NUM> stops the compressor <NUM> and brings the first opening/closing device <NUM> and the second opening/closing device <NUM> into the closed state. This enables the air conditioning apparatus <NUM> to suppress refrigerant leakage.

The refrigerant leakage sensor <NUM> may erroneously detect, as the refrigerant, for example, cigarette smoke or spray gas that is emitted into the space to be air-conditioned and taken into the indoor unit <NUM> by the operation of the indoor fan <NUM>.

Thus, after the execution of the anti-leakage measure operation, the control unit <NUM> determines whether the refrigerant concentration determined to be higher than the predetermined value is erroneously detected by the refrigerant leakage sensor <NUM>.

Specifically, when the refrigerant leakage sensor <NUM> detects a refrigerant concentration higher than the predetermined value, the control unit <NUM> operates and stops the indoor fan <NUM> and opens and closes the air direction plate <NUM> and acquires the refrigerant concentration or a change amount of the refrigerant concentration as occasion arises. Then, the control unit <NUM> determines whether the detection signal of the refrigerant leakage sensor <NUM> is generated by erroneous detection from the acquired refrigerant concentration or the required change amount of the refrigerant concentration.

When it is determined that the detection is erroneous detection, the control unit <NUM> brings the first opening/closing device <NUM> and the second opening/closing device <NUM> into the open state, resumes the operation of the compressor <NUM>, and returns the air conditioning apparatus <NUM> to normal operation. That is, when it is determined that the detection signal of the refrigerant leakage sensor <NUM> is generated by erroneous detection, the control unit <NUM> causes the air conditioning apparatus <NUM> to automatically resume the normal operation.

On the other hand, when it is determined that the detection is not erroneous detection, that is, there is refrigerant leakage, the control unit <NUM> continues the anti-leakage measure operation and notifies a user, through the operation unit 100a, that there is refrigerant leakage.

With this configuration, when there is refrigerant leakage, the control unit <NUM> can promptly suppress the refrigerant leakage. Moreover, when detection of the refrigerant leakage sensor <NUM> is erroneous detection, the control unit <NUM> can promptly return the air conditioning apparatus <NUM> to the normal operation.

Thus, the air conditioning apparatus <NUM> can reduce temperature changes in the space to be air-conditioned and improve the comfort of the user.

The control unit <NUM> further includes a storage unit <NUM> which stores various pieces of data related to the operation of the air conditioning apparatus <NUM>, such as the operation mode of the air conditioning apparatus <NUM> and the refrigerant concentration detected by the refrigerant leakage sensor <NUM>.

The storage unit <NUM> includes a leakage flag <NUM> indicating that there is refrigerant leakage. The leakage flag <NUM> is set by the control unit <NUM> when the control unit <NUM> determines that there is refrigerant leakage.

Next, an erroneous detection determination process for determining whether the detection signal of the refrigerant leakage sensor <NUM> is generated by erroneous detection, the erroneous detection determination process being performed by the control unit <NUM> of the air conditioning apparatus <NUM>, will be described with reference to <FIG>.

<FIG> is a flowchart showing an operation of the air conditioning apparatus <NUM>. Although <FIG> and the following description show a case where one of the refrigerant leakage sensors <NUM> of the three indoor units <NUM> included in the air conditioning apparatus <NUM> transmits a detection signal, the air conditioning apparatus <NUM> performs an operation similar to the described operation also when two or more of the refrigerant leakage sensors <NUM> of the indoor units <NUM> transmit detection signals.

When the air conditioning apparatus <NUM> is in operation, the control unit <NUM> acquires a refrigerant concentration detected by the refrigerant leakage sensor <NUM> at a predetermined frequency and determines whether the acquired refrigerant concentration is higher than the predetermined value (step ST1).

When it is determined that the refrigerant concentration detected by the refrigerant leakage sensor <NUM> is higher than the predetermined value (step ST1: YES), the control unit <NUM> causes a predetermined part to execute the anti-leakage measure operation.

Specifically, the control unit <NUM> stops the operation of the compressor <NUM> (step ST2). Moreover, the control unit <NUM> brings the first opening/closing device <NUM> and the second opening/closing device <NUM> into the closed state and operates the indoor fan <NUM> (step ST3).

This blocks the flow of the refrigerant and enables the air conditioning apparatus <NUM> to suppress refrigerant leakage. Furthermore, when there is leaked refrigerant inside the indoor unit <NUM>, the air conditioning apparatus <NUM> can release the leaked refrigerant inside the indoor unit <NUM> to the space to be air-conditioned by operating the indoor fan <NUM>.

Next, the control unit <NUM> determines whether the leakage flag <NUM> indicating that there is refrigerant leakage is set (step ST4).

When the leakage flag <NUM> is not set (step ST4: NO), the control unit <NUM> again acquires a refrigerant concentration detected by the refrigerant leakage sensor <NUM> and determines whether the refrigerant concentration has become equal to or lower than the predetermined value by the anti-leakage measure operation (step ST5).

When it is determined that the refrigerant concentration has become equal to or lower than the predetermined value (step ST5: YES), the control unit <NUM> brings the first opening/closing device <NUM> and the second opening/closing device <NUM> into the open state and stops the indoor fan <NUM> (step ST6).

Then, in this state, the control unit <NUM> again acquires a refrigerant concentration detected by the refrigerant leakage sensor <NUM> and determines whether the refrigerant concentration has remained unchanged or has decreased (step ST7).

When it is determined that the refrigerant concentration has remained unchanged or has decreased even though the first opening/closing device <NUM> and the second opening/closing device <NUM> are in the open state (step ST7: YES), the control unit <NUM> determines that there is no refrigerant leakage. That is, the control unit <NUM> determines that the refrigerant concentration determined in step ST1 is erroneously detected by the refrigerant leakage sensor <NUM> (step ST8).

On the other hand, when it is determined that the refrigerant concentration has increased in step ST7 (step ST7: NO), the control unit <NUM> turns the air direction plate <NUM> to close the air outlet <NUM> and stops the indoor fan <NUM> (step ST9). Then, in this state, the control unit <NUM> again acquires a refrigerant concentration detected by the refrigerant leakage sensor <NUM> and determines whether the refrigerant concentration has remained unchanged or has decreased (step ST10).

This prevents smoke or gas emitted into the space to be air-conditioned from entering the inside of the indoor unit <NUM> and enables the refrigerant leakage sensor <NUM> to detect the refrigerant concentration inside the indoor unit <NUM> with higher accuracy.

When it is determined that the refrigerant concentration has remained unchanged or has decreased (step ST10: YES), the control unit <NUM> determines that there is no refrigerant leakage. That is, the control unit <NUM> determines that the refrigerant concentration determined in step ST1 is erroneously detected by the refrigerant leakage sensor <NUM> (step ST11).

On the other hand, when it is determined that the refrigerant concentration has increased in step ST10 (step ST10: NO), there is a high possibility that there is refrigerant leakage inside the indoor unit <NUM>. Thus, the control unit <NUM> sets the leakage flag <NUM> (step ST12).

Then, the control unit <NUM> brings the first opening/closing device <NUM> and the second opening/closing device <NUM> into the closed state, operates the indoor fan <NUM>, and causes the predetermined part to execute the anti-leakage measure operation. The control unit <NUM> again determines whether the leakage flag <NUM> is set (step ST4) and determines that there is refrigerant leakage (step ST13) when the leakage flag <NUM> is set (step ST4: YES).

On the other hand, when it is determined in step ST5 that the refrigerant concentration has not become equal to or lower than the predetermined value (step ST5: YES), it is assumed that, for example, a large amount of refrigerant leaks out into the indoor unit <NUM> or a large amount of smoke or gas is emitted into the space to be air-conditioned.

Thus, the control unit <NUM> turns the air direction plate <NUM> to close the air outlet <NUM> and stops the indoor fan <NUM> (step ST14).

This prevents air from the space to be air-conditioned from flowing into the indoor unit <NUM>. That is, even if there is smoke or gas emitted into the space to be air-conditioned, the entry of the smoke or gas into the indoor unit <NUM> is prevented.

Then, in this state, the control unit <NUM> again acquires a refrigerant concentration detected by the refrigerant leakage sensor <NUM> and determines whether the refrigerant concentration has remained unchanged or has decreased (step ST15).

When it is determined that the refrigerant concentration has remained unchanged or has decreased (step ST15: YES), the control unit <NUM> turns the air direction plate <NUM> to again open the air outlet <NUM> (step ST16).

Then, in this state, the control unit <NUM> again acquires a refrigerant concentration detected by the refrigerant leakage sensor <NUM> and determines whether the refrigerant concentration has increased (step ST17). That is, in a state where air from the space to be air-conditioned flows in, the control unit <NUM> determines whether the refrigerant concentration has increased.

When it is determined that the refrigerant concentration has increased (step ST17: YES), the control unit <NUM> determines that there is no refrigerant leakage. That is, the control unit <NUM> determines that the refrigerant concentration determined in step ST1 is erroneously detected by the refrigerant leakage sensor <NUM>, for example, because a large amount of smoke or gas is emitted into the space to be air-conditioned (step ST18).

On the other hand, when it is determined that the refrigerant concentration has not increased (step ST17: NO), the control unit <NUM> shifts to step ST6 and performs steps ST7 to ST13 described above, thereby determining whether the detection signal of the refrigerant leakage sensor <NUM> is generated by erroneous detection.

When it is determined that the refrigerant concentration has increased (step ST15: NO), there is a high possibility that there is refrigerant leakage inside the indoor unit <NUM> because the refrigerant concentration inside the indoor unit <NUM> has increased in a state where the entry of air from the space to be air-conditioned is prevented. Thus, the control unit <NUM> sets the leakage flag <NUM> (step ST19).

In this manner, when the refrigerant leakage sensor <NUM> detects a refrigerant concentration higher than the predetermined value, the air conditioning apparatus <NUM> executes the anti-leakage measure operation, and the control unit <NUM> then determines whether the detection of the refrigerant leakage sensor <NUM> is erroneous detection.

Then, when it is determined that the detection is erroneous detection, the control unit <NUM> brings the first opening/closing device <NUM> and the second opening/closing device <NUM> into the open state, resumes the operation of the compressor <NUM>, and returns the air conditioning apparatus <NUM> to the normal operation.

On the other hand, when it is determined that the detection is not erroneous detection, that is, there is refrigerant leakage, the control unit <NUM> continues the anti-leakage measure operation and notifies the user, through the operation unit 100a, that there is refrigerant leakage.

As described above, according to the present embodiment, the air conditioning apparatus <NUM> includes the outdoor unit <NUM>, the indoor unit <NUM> including the indoor fan <NUM>, the air outlet <NUM>, and the refrigerant leakage sensor <NUM> which detects the refrigerant, the liquid-side pipes <NUM>, <NUM> and the gas-side pipe <NUM> which connect the outdoor unit <NUM> and the indoor unit <NUM>, and the first opening/closing device <NUM> and the second opening/closing device <NUM> which open and close these pipes. The air conditioning apparatus <NUM> includes the control unit <NUM> which, when the refrigerant leakage sensor <NUM> detects a refrigerant concentration higher than the predetermined value, closes the first opening/closing device <NUM> and the second opening/closing device <NUM> and determines whether the detection of the refrigerant leakage sensor <NUM> is erroneous detection.

With this configuration, the control unit <NUM> determines whether there is refrigerant leakage in a state where the first opening/closing device <NUM> and the second opening/closing device <NUM> are closed. Thus, the control unit <NUM> can determine whether detection of the refrigerant leakage sensor <NUM> is erroneous detection while more reliably suppressing refrigerant leakage.

According to the present embodiment, when the refrigerant leakage sensor <NUM> detects a refrigerant concentration higher than the predetermined value, the control unit <NUM> closes the first opening/closing device <NUM> and the second opening/closing device <NUM> and drives the indoor fan <NUM> for a predetermined time.

Then, when the refrigerant leakage sensor <NUM> detects a refrigerant concentration higher than the predetermined value, the control unit <NUM> stops the indoor fan <NUM> and closes the air direction plate <NUM>.

Then, when the refrigerant concentration detected by the refrigerant leakage sensor <NUM> remains substantially equal to or decreases from the concentration previously detected, the control unit <NUM> opens the air direction plate <NUM>.

Then, when the refrigerant concentration detected by the refrigerant leakage sensor <NUM> becomes higher than the concentration previously detected, the control unit <NUM> determines whether detection of the refrigerant leakage sensor <NUM> is erroneous detection.

With this configuration, the control unit <NUM> acquires the refrigerant concentration in a case where the air direction plate <NUM> is open and the refrigerant concentration in a case where the air direction plate <NUM> is closed and determines whether the detection signal of the refrigerant leakage sensor <NUM> is generated by erroneous detection.

Thus, for example, even in the space to be air-conditioned constantly filled with a large amount of smoke or gas, such as a smoking area, the control unit <NUM> can achieve erroneous detection determination for the refrigerant leakage sensor <NUM> with higher accuracy.

Then, when the refrigerant leakage sensor <NUM> detects a refrigerant concentration equal to or lower than the predetermined value, the control unit <NUM> opens the first opening/closing device <NUM> and the second opening/closing device <NUM> and stops the indoor fan <NUM>.

Then, when a refrigerant concentration detected by the refrigerant leakage sensor <NUM> remains substantially equal to or decreases from the concentration previously detected, the control unit <NUM> determines that detection of the refrigerant leakage sensor <NUM> is erroneous detection.

This enables the control unit <NUM> to determine that the detection signal of the refrigerant leakage sensor <NUM> is generated by erroneous detection when determining that the refrigerant concentration has temporarily increased due to, for example, spray gas or cigarette smoke.

According to the present embodiment, the control unit <NUM> determines that there is refrigerant leakage by setting the leakage flag <NUM>.

This enables the control unit <NUM> to determine that there is refrigerant leakage on the erroneous detection determination process.

In the above embodiment, when it is determined that the detection is not erroneous detection, that is, there is refrigerant leakage, the control unit <NUM> continues the anti-leakage measure operation and notifies the user, through the operation unit 100a, that there is refrigerant leakage. However, the present invention is not limited thereto. While the erroneous detection determination process is being performed, the control unit <NUM> may display, on an element provided with a display unit, such as the operation unit 100a, that the erroneous detection determination is being performed to notify the user of the erroneous detection determination.

Claim 1:
An air conditioning apparatus (<NUM>) comprising:
an outdoor unit (<NUM>);
an indoor unit (<NUM>) including an air blowing fan (<NUM>), an air outlet (<NUM>) for blowing out air fed by the air blowing fan (<NUM>), and a refrigerant leakage sensor (<NUM>) configured to detect a refrigerant;
a refrigerant pipe (<NUM>, <NUM>, <NUM>) connecting the outdoor unit (<NUM>) and the indoor unit (<NUM>);
an opening/closing device (<NUM>, <NUM>) configured to open and close the refrigerant pipe, characterized in that
the indoor unit (<NUM>) includes an air direction plate (<NUM>) capable of opening and closing the air outlet (<NUM>), and in that
the air conditioning apparatus (<NUM>) comprises a control unit (<NUM>) configured to close the opening/closing device (<NUM>, <NUM>) and drive the air blowing fan (<NUM>) for a predetermined time when the refrigerant leakage sensor (<NUM>) detects a refrigerant concentration higher than a predetermined value,
then stop the air blowing fan (<NUM>) and close the air direction plate (<NUM>) when the refrigerant leakage sensor (<NUM>) detects a refrigerant concentration higher than the predetermined value,
then open the air direction plate when a refrigerant concentration detected by the refrigerant leakage sensor (<NUM>) remains substantially equal to or decreases from the concentration previously detected, and
then determine that detection of the refrigerant leakage sensor (<NUM>) is erroneous detection when a refrigerant concentration detected by the refrigerant leakage sensor (<NUM>) becomes higher than the concentration previously detected.