Patent Description:
In recent years, it has been considered that refrigerant for use in an air-conditioning apparatus is changed to, for example, R32 that has a low global warming potential, in order to take measures against an environmental problem such as global warming or ozone depletion. However, various kinds of refrigerants that are applied in measures against an environmental problem include flammable or mildly flammable refrigerant. Therefore, it has been proposed that a refrigerant sensor is provided in an indoor unit to detect a leak of refrigerant from a refrigerant circuit (see, for example, Patent Literature <NUM>).

Patent Literature <NUM>, according to its abstract, states that, to provide an air conditioner in which even when refrigerant leaks, an indoor side does not reach a combustible concentration, an air conditioner includes: a first pipeline space that is arranged on the side surface of a heat exchanger, and stores a plurality of first pipelines containing a pipeline in which refrigerant circulates; and a second pipeline space that stores a plurality of second pipelines connected to the plurality of first pipelines and extending to an outdoor side, stores a communication passage being an exhaust gas passage for discharging leaked refrigerant to the outdoor side in leakage of refrigerant, and is connected to the first pipeline space.

Patent Literature <NUM>, according to its abstract, states that, to provide an indoor unit of an air conditioner that can properly detect leakage of a refrigerant and is easily maintained, an indoor unit of an air conditioner comprises: a cabinet; a heat exchanger including a pipe through which a refrigerant having a higher specific gravity than that of air is passed; a drain pan arranged below the heat exchanger; removable covers located on the back side of the cabinet; and sensors arranged at positions facing the removable cover to detect leakage the refrigerant.

Patent Literature <NUM>, according to its abstract, states that, to provide a refrigerant-sensing device that can be used in a shared form even among devices having differing structures, and an indoor unit for an air conditioner in which the refrigerant-sensing device is used, the refrigerant-sensing device and the indoor unit for an air conditioner comprise a refrigerant-sensing air path of which both ends are connected to a main air path that extends from an inlet of the indoor unit for an air conditioner to an outlet thereof, and a refrigerant-sensing sensor for sensing refrigerant in the interior of the refrigerant-sensing air path.

In an indoor unit described in Patent Literature <NUM>, a leak detection operation in which air is circulated in the indoor unit after an air outlet is closed is performed to detect refrigerant. Because of this operation, it is possible to guide, with airflow, leaking refrigerant to a refrigerant sensor even if a place where a refrigerant leak occurs is located away from a place where the refrigerant sensor is provided. Accordingly, the refrigerant leak can be detected.

However, since the air outlet is open during a normal operation, air does not easily circulate in the indoor unit. As a result, there is a possibility that the refrigerant leak cannot be detected.

The present invention is made to solve the above problem, and relates to an air-conditioning apparatus capable of detecting a refrigerant leak even when the refrigerant leak occurs during the operation of the air-conditioning apparatus.

An air-conditioning apparatus according to the present invention is defined in claim <NUM>.

The air-conditioning apparatus of the embodiment of the present invention is capable of detecting a refrigerant leak even during operation of the air-conditioning apparatus.

An air-conditioning apparatus according to Embodiment <NUM> of the present invention will be described with reference to the above figures, for example. In each of the figures, components that are the same as or equivalent to those in a previous figure or figures are denoted by the same reference signs, and their descriptions will be omitted or simplified as appropriate. For example, the shapes, sizes, and locations of the components as illustrated in the figures can be changed as appropriate within the scope of the present invention that is defined by the appended claims.

<FIG> is a perspective view of the air-conditioning apparatus according to Embodiment <NUM> of the present invention. Regarding Embodiment <NUM>, a two-way blowing type indoor unit that has air outlets in two directions and that is at least partially embedded in a ceiling of a room will be described. An air-conditioning apparatus <NUM> includes a housing <NUM> and a decorative panel <NUM>. The housing <NUM> houses components such a fan and a heat exchanger that will descried later; the housing <NUM> is formed in the shape of a box having an opening portion on a lower side; and the housing <NUM> is provided in an opening formed in a ceiling. The decorative panel <NUM> is formed of a rectangular plate body, and is attached to the opening portion of the housing <NUM> in such a manner as to face an indoor space that is an air-conditioned space. The decorative panel <NUM> has air inlets <NUM> and air outlets <NUM>, and the air inlets <NUM> extend along long sides of the decorative panel <NUM> to allow indoor air to be sucked. The air inlets <NUM> are inlets through which indoor air is sucked along the long sides thereof, and air outlets <NUM> are located outward of the respective air inlets <NUM> and allow air conditioned in the air-conditioning apparatus <NUM> to blow out to the indoor space. The air-conditioning apparatus <NUM> is connected to an outdoor unit (not illustrated) by a refrigerant pipe and circulates refrigerant between the air-conditioning apparatus <NUM> and the outdoor unit.

<FIG> is a top view of the air-conditioning apparatus as illustrated in <FIG>. <FIG> is a view of the housing <NUM> that is obtained as viewed from above, with an upper surface of the housing <NUM> removed from the housing <NUM>. The housing <NUM> has a first space <NUM> in which a fan <NUM> and a heat exchanger <NUM> are provided and a second space <NUM> in which a refrigerant sensor <NUM> and a pipe (not illustrated) are provided. The first space <NUM> and the second space <NUM> are adjacent to each other in parallel with a surface of the ceiling and along the air inlets <NUM> and the air outlets <NUM>. The first space <NUM> and the second space <NUM> are partitioned off by a partition plate <NUM>.

<FIG> is a side view illustrating a section taken along line A-A in <FIG>, as viewed in a direction indicated by arrows for the line A-A. <FIG> is a side view illustrating a section taken along line B-B in <FIG>, as viewed in a direction indicated arrows for line B-B. The fan <NUM> sucks indoor air into the housing <NUM> through the air inlets <NUM>, and blows conditioned-air into the indoor space through the air outlets <NUM> after the conditioned-air is obtained by causing the air to be subjected to heat exchange. The fan <NUM> includes a motor <NUM> and a fan <NUM>. When the motor <NUM> is driven, the fan <NUM> is rotated to generate airflow.

The heat exchanger <NUM> causes heat exchange to be performed between air sucked by the fan <NUM> and refrigerant, and is provided downstream of the fan <NUM> in the flow of air and in such a manner as to surround the fan <NUM>. The heat exchanger <NUM> is, for example, a finned tube heat exchanger. The heat exchanger <NUM>, a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and other components not illustrated, form a refrigeration cycle circuit. At least the compressor and the outdoor heat exchanger of the refrigeration cycle circuit are mounted together with an outdoor fan in the outdoor unit. The outdoor fan sends outside air to the outdoor heat exchanger. In a cooling operation, the heat exchanger <NUM> operates as an evaporator, and when the air sent by the fan <NUM> passes through the heat exchanger <NUM>, the air exchanges with refrigerant and is thus cooled. On the other hand, in a heating operation, the heat exchanger <NUM> operates as a condenser, and when the air sent by the fan <NUM> passes through the heat exchanger <NUM>, the air exchanges with refrigerant and is thus heated. As the refrigerant, a low-GWP refrigerant that is hydrochlorofluorocarbon such as R32, and that is, for example, a flammable or mildly flammable refrigerant, is used. In Embodiment <NUM>, R32 is used.

The heat exchanger <NUM> of Embodiment <NUM> has a section that has such a substantially U-shape as to surround three sides of an outer periphery of the fan <NUM>. Between one end portion 22a and another end portion 22b of the heat exchanger <NUM>, the partition plate <NUM>, which is formed in the shape of a flat rectangular plate, is provided to cover the other side of the fan <NUM>. That is, the entire outer periphery of the fan <NUM> is surrounded by the heat exchanger <NUM> and the partition plate <NUM>.

The partition plate <NUM> partitions off the first space <NUM> in which the fan <NUM> and the heat exchanger <NUM> are located and the second space <NUM> in which the refrigerant sensor <NUM> and the pipe (not illustrated) are located. In the partition plate <NUM>, a rectangular opening portion <NUM> is formed. The opening portion <NUM> has, for example, a length of approximately <NUM> to <NUM> in a horizontal direction and a length of approximately <NUM> to <NUM> in a vertical direction. The opening portion <NUM> is closed by a maintenance panel <NUM>. The maintenance panel <NUM> has a size greater than or nearly equal to the size of the opening portion <NUM>. The maintenance panel <NUM> is detachably attached to the partition plate <NUM> by, for example, screws. The maintenance panel <NUM> is detached for cleaning of the fan <NUM> or maintenance of a drain pan provided below the heat exchanger <NUM>. In the other cases (including the case in which the air-conditioning apparatus <NUM> is in operation), the maintenance panel <NUM> is attached to the partition plate <NUM> to close the opening portion <NUM>.

Furthermore, an air inlet port <NUM> and an air outlet port <NUM> are formed in the partition plate <NUM>. The air inlet port <NUM> and the air outlet port <NUM> are, for example, openings each having a rectangular shape and having a length of approximately <NUM> to <NUM> in the horizontal direction and a length of approximately <NUM> to <NUM> in the vertical direction. The air inlet port <NUM> is an opening through which air flows from the first space <NUM> into the second space <NUM>, and is formed in a lower portion of the partition plate <NUM> where the pressure of air from the fan <NUM> is high. The air outlet port <NUM> is an opening through which air flows from the second space <NUM> into the first space <NUM>, and is formed in an upper portion of the partition plate <NUM> where the pressure of air from the fan <NUM> is low. At the portion where the air inlet port <NUM> is formed, the pressure of air from the fan <NUM> is higher than that at the portion where the air outlet port <NUM> is formed. It is therefore possible to cause some of air sucked into the first space <NUM> to flow into the second space <NUM> through the air inlet port <NUM>.

The refrigerant sensor <NUM> is provided in the second space <NUM> and is configured to detect whether refrigerant is contained in air in the second space <NUM> or not. To detect refrigerant efficiently, preferably, the refrigerant sensor <NUM> should be provided at a position in the second space <NUM> where refrigerant easily collects. Thus, the refrigerant sensor <NUM> is provided in a lower region in the second space <NUM> and closer to the air outlet port <NUM> than to the air inlet port <NUM>.

Next, an air-conditioning operation of the air-conditioning apparatus <NUM> according to Embodiment <NUM> will be briefly described. In the cooling operation, high-temperature and high-pressure gas refrigerant that is discharged from the compressor of the refrigeration cycle circuit after being obtained by compression performed by the compressor flows into the outdoor heat exchanger (condenser) via the four-way valve. The gas refrigerant that has flowed into the outdoor heat exchanger exchanges heat with outside air sent by the outdoor fan to condense into low-temperature refrigerant. The low-temperature refrigerant then flows out of the outdoor heat exchanger. The refrigerant that has flowed out of the outdoor heat exchanger is expanded and reduced in pressure by an expansion device to change into low-temperature and low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the heat exchanger <NUM> (evaporator) and exchanges heat with indoor air sent by the fan <NUM> to evaporate and change into low-temperature and low-pressure gas refrigerant. The low-temperature and low pressure gas refrigerant flows out of the heat exchanger <NUM>. In the above heat exchange, heat from the indoor air is received by the refrigerant and the indoor air is cooled. The cooled indoor air is blown as cold air into the indoor space. The gas refrigerant that has flowed of the heat exchanger <NUM> is sucked into the compressor via the four-way valve and is re-compressed. In the refrigeration cycle circuit, during the cooling operation, the above series of operations are continuously repeated.

By the fan <NUM>, indoor air is sucked into the air-conditioning apparatus <NUM> through the air inlets <NUM> and is then blown out from the air-conditioning apparatus <NUM>. To be more specific, the air sucked by the fan <NUM> passes through the heat exchanger <NUM> and is cooled. The air is then blown out as cold air into the indoor space through the air outlets <NUM>.

In the heating operation, high-temperature and high-pressure gas refrigerant discharged from the compressor after being obtained by compression by the compressor flows into the heat exchanger <NUM> (condenser) via the four-way valve. The gas refrigerant that has flowed into the heat exchanger <NUM> exchanges heat with indoor air sent by the fan <NUM> to condense into low-temperature refrigerant, and then the low-temperature refrigerant flows out of the heat exchanger <NUM>. In the above heat exchange, the indoor air receives heat from the refrigerant and is thus heated, and is then blown out as warm air into the indoor space. The above refrigerant that has flowed out of the heat exchanger <NUM> is expanded and reduced in pressure by the expansion device to change into low-temperature and low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the outdoor heat exchanger (evaporator) and exchanges heat with outside air sent by the outdoor fan to evaporate and change into low-temperature and low-pressure gas refrigerant. The low-temperature and low-pressure gas refrigerant flows out of the outdoor heat exchanger. The gas refrigerant that has flowed out of the outdoor heat exchanger is sucked into the compressor via the four-way valve and is re-compressed. In the refrigeration cycle circuit, in the heating operation, the above series of operations are continuously repeated.

By the fan <NUM>, indoor air is sucked into the air-conditioning apparatus <NUM> through the air inlets <NUM> and is flown out of the air-conditioning apparatus <NUM>. To be more specific, the air sucked by the fan <NUM> passes through the heat exchanger <NUM> and is heated. The air is blown out as warm air into the indoor space through the air outlets <NUM>.

Next, the following description is made with respect to the air-conditioning operation in the case where refrigerant leaks into the air-conditioning apparatus <NUM> during the cooling operation or the heating operation. Regarding Embodiment <NUM>, the air-conditioning operation in the case where refrigerant leaks from the heat exchanger <NUM> located in the first space <NUM> will be described. When refrigerant leaks from the heat exchanger <NUM> in the first space <NUM>, the refrigerant is mixed into air sucked by the fan <NUM>. Some of the air containing the refrigerant flows from the first space <NUM> into the second space <NUM> through the air inlet port <NUM>. When the air containing the refrigerant flows into the second space <NUM>, the refrigerant sensor <NUM> detects the refrigerant and makes a notification indicating this refrigerant leak.

The air inlet port <NUM> is formed at a location where the pressure of air from the fan <NUM> is higher than that at the air outlet port <NUM>. Because of this configuration, the air containing refrigerant in the first space <NUM> easily flows into the second space <NUM>, in which the refrigerant sensor <NUM> is provided, through the air inlet port <NUM>.

Furthermore, the air inlet port <NUM> is provided in the lower portion of the partition plate <NUM>. Because of this configuration, since R32 refrigerant adopted in Embodiment <NUM> has a higher specific gravity than that of air, the concentration of refrigerant in a lower region of the air-conditioning apparatus is higher and air that contains refrigerant such that the concentration of the refrigerant is higher can thus be made to flow into the second space <NUM>.

Furthermore, the air outlet port <NUM> is provided in the upper portion of the partition plate <NUM>. Because of this configuration, since the R32 refrigerant adopted in Embodiment <NUM> has a higher specific gravity than that of air, and the concentration of the refrigerant in an upper region in the air-conditioning apparatus <NUM> is lower, and air that contains refrigerant such that the concentration of the refrigerant is lower can be made to flow into the first space <NUM>. That is, the air inlet port <NUM> is provided at a lower location than the air outlet port <NUM>, and the concentration of the refrigerant in the second space <NUM> can thus be increased, and the accuracy of refrigerant detection by the refrigerant sensor <NUM> can be improved.

It is preferable that the area of the air inlet port <NUM> be larger than that of the air outlet port <NUM>. Because of this configuration, air containing refrigerant in the first space <NUM> easily flows into the second space <NUM>, and the air containing refrigerant does not easily flow from the second space <NUM> into the first space <NUM>; that is, the air containing refrigerant can be stayed in the second space <NUM> and the accuracy of refrigerant detection by the refrigerant sensor <NUM> can be improved.

The refrigerant sensor <NUM> is provided in the lower region in the second space <NUM>. Because of this configuration, the accuracy of the refrigerant detection can be improved, since the R32 refrigerant adopted in Embodiment <NUM> has a specific gravity higher than that of air, and the concentration of the refrigerant in a lower region in the air-conditioning apparatus <NUM> is thus higher.

In addition, the refrigerant sensor <NUM> is provided closer to the air outlet port <NUM> than to the air inlet port <NUM>. This location is not easily affected by air from the air inlet port <NUM>, and air gently flows at the location. It is therefore possible to improve the accuracy of refrigerant detection.

Furthermore, it is preferable that the refrigerant sensor <NUM> be provided below the air outlet port <NUM> and adjacent to the partition plate <NUM>. By applying this configuration, it is possible to improve the accuracy of refrigerant detection, because the refrigerant sensor <NUM> is provided at a position where refrigerant easily collects. It should be noted that the refrigerant sensor <NUM> does not need to be completely adjacent to the partition plate <NUM>, and it suffices that the refrigerant sensor <NUM> is provided in the vicinity of the partition plate <NUM>.

As described above, the air-conditioning apparatus <NUM> according to Embodiment <NUM> includes the housing <NUM> in which the first space <NUM> and the second space <NUM> are provided adjacent to each other, and that includes: the fan <NUM> that is provided in the first space <NUM> and sucks air into the housing <NUM>; the heat exchanger <NUM> that is provided in the first space <NUM> and causes heat exchange to be performed between air sucked by the fan <NUM> and refrigerant; the refrigerant sensor <NUM> that is provided in the second space <NUM> and detects refrigerant; and the partition plate <NUM> that partitions off the first space <NUM> and the second space <NUM> and has the air inlet port <NUM> and the air outlet port <NUM>.

In the above configuration, even when refrigerant leaks during the operation of the air-conditioning apparatus, this refrigerant leak can be detected.

In the air-conditioning apparatus <NUM> according to Embodiment <NUM>, the air inlet port <NUM> is provided at a location where the pressure of air from the fan <NUM> is higher than that at the air outlet port <NUM>.

In the above configuration, air containing refrigerant in the first space <NUM> easily flows into the second space <NUM> in which the refrigerant sensor <NUM> is provided, through the air inlet port <NUM>.

In the air-conditioning apparatus <NUM> according to Embodiment <NUM>, the refrigerant has a higher specific gravity than that of air, the refrigerant sensor <NUM> is provided in the lower region in the second space <NUM>, and the air inlet port <NUM> is provided below the air outlet port <NUM>.

Because of the above configuration, the refrigerant concentration in the second space <NUM> can be increased, and the accuracy of refrigerant detection by the refrigerant sensor <NUM> can be improved, because an R32 refrigerant has a higher specific gravity than that of air and the refrigerant concentration in the lower region in the air-conditioning apparatus <NUM> is increased.

In the air-conditioning apparatus <NUM> according to Embodiment <NUM>, the area of the air inlet port <NUM> is larger than the area of the air outlet port <NUM>.

Because of this configuration, air containing refrigerant can be stayed in the second space <NUM>, and the accuracy of refrigerant detection by the refrigerant sensor <NUM> can be improved.

In the air-conditioning apparatus <NUM> according to Embodiment <NUM>, the refrigerant sensor <NUM> is provided closer to the air outlet port <NUM> than to the air inlet port <NUM>, and located below the air outlet port <NUM>.

Because of this configuration, the above location is not easily affected by air from the air inlet port <NUM>, and air gently flows at the location. It is therefore possible to improve the accuracy of refrigerant detection.

In the air-conditioning apparatus <NUM> according to Embodiment <NUM>, the refrigerant sensor <NUM> is provided adjacent to the partition plate <NUM>.

In this configuration, since the refrigerant sensor <NUM> is located at a position where refrigerant easily collects, the accuracy of refrigerant detection can be improved.

The technical scope of the present invention is not limited to the scope as described above regarding Embodiment <NUM>. Embodiment <NUM> can be variously modified or improved without departing from the subject matter of the present invention, as long as such modified or improved embodiments also fall within the technical scope of the present invention that is defined by the appended claims.

Although, for example, regarding Embodiment <NUM>, a two-way blowing type indoor unit is described above as the air-conditioning apparatus <NUM>, an indoor unit having air outlets in four directions may be used.

Claim 1:
An air-conditioning apparatus (<NUM>) comprising:
a housing (<NUM>) having a first space (<NUM>) and a second space (<NUM>) that are adjacent to each other;
a fan (<NUM>) provided in the first space (<NUM>), and configured to suck air into the housing (<NUM>);
a heat exchanger (<NUM>) provided in the first space (<NUM>), and configured to cause heat exchange to be performed between the air sucked by the fan (<NUM>) and refrigerant;
a refrigerant sensor (<NUM>) provided in the second space (<NUM>), and configured to detect the refrigerant; and
a partition plate (<NUM>) provided to partition off the first space (<NUM>) and the second space (<NUM>),
wherein the refrigerant has a higher specific gravity than air,
wherein the refrigerant sensor (<NUM>) is provided in a lower region in the second space (<NUM>),
characterized in that the partition plate (<NUM>) has an air inlet port (<NUM>) and an air outlet port (<NUM>), wherein the air inlet port (<NUM>) is provided below the air outlet port (<NUM>).