Patent Description:
An example of an indoor unit of an air-conditioning apparatus according to the related art includes an air cleaning filter disposed between an air inlet and an indoor heat exchanger so that air that enters through the air inlet passes through the air cleaning filter and is cleaned (see, for example, Patent Literature <NUM>).

The indoor unit of the air-conditioning apparatus described in Patent Literature <NUM> is configured such that accommodating portions (333b) that accommodate air cleaning filters (<NUM>) are disposed behind a front panel (<NUM>). <CIT> discloses an air conditioner including a main chassis receiving various components inside, a heat exchanger installed inside the main chassis so as to exchange heat with a room air, a blow fan installed inside the main chassis so as to suck in and blow out the room air, a front panel attached to a front side of the main chassis and having an intake inlet at a front face so as to make an air flow in the heat exchanger, and an intake panel installed at the front face of the front panel to revolve to move so as to close/open the intake intake inlet selectively, the intake panel installed at the front face of the front panel so as to be detachable. The disclosure provides a compact air conditioner having an improved exterior. <CIT> discloses an air cleaner provided with a dust collecting unit detachably mounted on a fixing frame mounted on the indoor machine side. In this case, a boss par for locking is formed at the body case of a dust collecting unit, and the boss part for locking is detachably locked. A lock part having an elastic part to hold this lock state is mounted on fixing frame and the elastic part is situated in the delivery packing attitude of an indoor machine on the side not exerted by the own weight of the dust collecting unit. <CIT> provides an air-conditioner for preventing degradation of the air-conditioning capacity and reducing diffusion of air containing fine dust and odor indoors. <CIT> discloses that a hollow fiber type humidifier extracts moisture contained in off-gas discharged from a fuel cell and by giving the extracted moisture to a reactant gas, humidifies the reactant gas. A control unit estimates whether a crease has been generated or not in the hollow fiber membrane in the hollow fiber type humidifier and when it is estimated that the crease has been generated in the hollow fiber membrane of the hollow fiber type humidifier, the supply quantity of the reactant gas supplied to the fuel cell is increased. <CIT> is directed to an indoor unit for an air conditioner, wherein the indoor unit includes a front frame, a main chassis coupled on a rear portion of the front frame, an air discharge vane provided on a lower end of the front frame to control a discharge direction of cooled air, and an connecting frame provided in rear of the air discharge vane to allow an assembling or maintenance of the air discharge vane to be easily performed.

The indoor unit of the air-conditioning apparatus described in Patent Literature <NUM> is configured such that the air cleaning filters, which have a high airflow passage resistance, are inclined. Since the air cleaning filters are disposed behind the front panel, the air cleaning filters impede the flow of air toward a lower section of the indoor heat exchanger. When the flow of air toward the lower section of the indoor heat exchanger is impeded, the amount of air that contributes to heat exchange in the indoor heat exchanger is reduced and the performance of the indoor heat exchanger is degraded.

Thus, an indoor unit of an air-conditioning apparatus including an air cleaning filter that is separate from a pre-filter is required to reduce degradation in the performance of an indoor heat exchanger and ensure sufficient air cleaning performance of the air cleaning filter at the same time.

The present invention has been made to overcome the above-described problem, and an object of the present invention is to provide an indoor unit of an air-conditioning apparatus that enables an air cleaning filter to provide an air cleaning effect with less degradation in the performance of a heat exchanger.

An indoor unit of an air-conditioning apparatus according to an embodiment of the present invention includes a casing having an air inlet provided solely at a top face of the casing, an air outlet provided at a lower portion of the casing, and an airflow passage through which the air inlet and the air outlet communicate with each other; a fan disposed in the casing; a heat exchanger disposed upstream in airflow of the fan in the casing; a first filter disposed upstream in airflow of the heat exchanger in the casing; a front panel attached at a front portion of the casing; a protrusion provided at a back face of the front panel; and a second filter disposed behind the front panel and between the protrusion and the heat exchanger, the second filter being separate from the first filter, wherein the heat exchanger includes a bend portion at which the heat exchanger is bent at a certain position in a height direction, and the indoor unit being characterized by that: the protrusion, the second filter, and the bend portion align along a horizontal straight line in side view.

The indoor unit of the air-conditioning apparatus according to the embodiment of the present invention is configured such that the protrusion is provided on the back face of the front panel and that the second filter is disposed between the protrusion and the heat exchanger. Accordingly, a flow of air directed from the front panel to the air cleaning filter can be generated by the protrusion, so that the air cleaning effect can be obtained with less degradation in the performance of the heat exchanger.

Embodiment of the present invention will now be described with reference to the drawings. <FIG> and other drawings do not necessarily depict the actual relative sizes of the components. In addition, elements denoted by the same reference signs are the same or corresponding elements in <FIG> and other figures. This applies throughout the entire specification. In addition, the configurations of the constituent elements described in the full text of the specification are merely examples, and are not limited to the description.

<FIG> is a schematic diagram illustrating an example of a refrigerant circuit structure of an air-conditioning apparatus <NUM> including an indoor unit <NUM> according to Embodiment of the present invention. In <FIG>, the solid line arrows indicate the flow of refrigerant in a cooling operation, and the broken line arrows indicate the flow of refrigerant in a heating operation.

As illustrated in <FIG>, the air-conditioning apparatus <NUM> includes the indoor unit <NUM> and an outdoor unit <NUM>.

The indoor unit <NUM> includes an indoor heat exchanger <NUM> and an indoor fan <NUM>.

The outdoor unit <NUM> includes an outdoor heat exchanger <NUM>, an outdoor fan <NUM>, a compressor <NUM>, a four-way valve <NUM>, and an expansion valve <NUM>.

A refrigerant circuit <NUM> is formed by connecting the indoor unit <NUM> and the outdoor unit <NUM> to each other with a gas-side connection pipe <NUM> and a liquid-side connection pipe <NUM>.

The operation of the air-conditioning apparatus <NUM> can be switched between a cooling operation and a heating operation by switching the paths formed by the four-way valve <NUM>. The air-conditioning apparatus <NUM> performs the cooling operation when the paths formed by the four-way valve <NUM> are as indicated by the solid lines in <FIG>. The air-conditioning apparatus <NUM> performs the heating operation when the paths formed by the four-way valve <NUM> are as indicated by the broken lines in <FIG>.

The indoor unit <NUM> is disposed in a space by which it can supply cooling energy or heating energy to the space or an air-conditioning target space (for example, an air-conditioning target space such as an indoor space, or another space connected to the air-conditioning target space by a duct or the like). The indoor unit <NUM> has a function of cooling or heating the air-conditioning target space by using cooling energy or heating energy supplied by the outdoor unit <NUM>.

The indoor heat exchanger <NUM> functions as a condenser in the heating operation and as an evaporator in the cooling operation. The indoor heat exchanger <NUM> may be composed of, for example, a fin-and-tube heat exchanger.

The indoor heat exchanger <NUM> corresponds to a "heat exchanger" according to the present invention.

The indoor fan <NUM> is arranged to be surrounded by the indoor heat exchanger <NUM> (see <FIG>), and supplies air, which serves as heat exchange fluid, to the indoor heat exchanger <NUM>. The indoor fan <NUM> may be composed of, for example, a cross-flow fan.

The indoor fan <NUM> corresponds to a "fan" according to the present invention.

The outdoor unit <NUM> is disposed in a space other than the air-conditioning target space (for example, an outdoor space), and has a function of supplying cooling energy or heating energy to the indoor unit <NUM>.

The outdoor heat exchanger <NUM> functions as an evaporator in the heating operation and as a condenser in the cooling operation.

The outdoor fan <NUM> supplies air, which serves as heat exchange fluid, to the outdoor heat exchanger <NUM>. The outdoor fan <NUM> may be composed of, for example, a propeller fan having a plurality of blades.

The compressor <NUM> compresses refrigerant and discharges the compressed refrigerant. The compressor <NUM> may be composed of, for example, a rotary compressor or a scroll compressor. When the outdoor heat exchanger <NUM> functions as a condenser, the refrigerant discharged from the compressor <NUM> flows into the outdoor heat exchanger <NUM> through a refrigerant pipe. When the outdoor heat exchanger <NUM> functions as an evaporator, the refrigerant discharged from the compressor <NUM> passes through the indoor unit <NUM> and then flows into the outdoor heat exchanger <NUM> through a refrigerant pipe.

The four-way valve <NUM> is connected to a discharge side of the compressor <NUM> and switches the flow of the refrigerant between that for the heating operation and that for the cooling operation. A combination of two-way valves or a combination of three-way valves may be provided instead of the four-way valve <NUM>.

The expansion valve <NUM> expands the refrigerant that has passed through the indoor heat exchanger <NUM> or the outdoor heat exchanger <NUM>, thereby reducing the pressure of the refrigerant. The expansion valve <NUM> may be composed of, for example, an electric expansion valve capable of adjusting the flow rate of the refrigerant. The expansion valve <NUM> may be included in the indoor unit <NUM> instead of the outdoor unit <NUM>.

The refrigerant circuit <NUM> is formed by connecting the compressor <NUM>, the indoor heat exchanger <NUM>, the expansion valve <NUM>, and the outdoor heat exchanger <NUM> with refrigerant pipes including the gas-side connection pipe <NUM> and the liquid-side connection pipe <NUM>.

The four-way valve <NUM> may be omitted so that the direction in which the refrigerant flows through the refrigerant circuit <NUM> is constant.

The operation of the air-conditioning apparatus <NUM> will be described together with the flow of the refrigerant. The operation of the air-conditioning apparatus <NUM> described below is an example in which the heat exchange fluid is air and fluid that exchanges heat with the heat exchange fluid is refrigerant.

The cooling operation performed by the air-conditioning apparatus <NUM> will now be described.

When the compressor <NUM> is activated, high-temperature high-pressure refrigerant in a gas state is discharged from the compressor <NUM>. After that, the refrigerant flows as indicated by the solid line arrows. The high-temperature high-pressure gas refrigerant (single phase) discharged from the compressor <NUM> passes through the four-way valve <NUM> and flows into the outdoor heat exchanger <NUM>, which functions as a condenser. The high-temperature high-pressure gas refrigerant that has flowed into the outdoor heat exchanger <NUM> exchanges heat with air supplied by the outdoor fan <NUM>, so that the high-temperature high-pressure gas refrigerant is condensed into high-pressure liquid refrigerant (single phase).

The high-pressure liquid refrigerant flowing out of the outdoor heat exchanger <NUM> flows into the expansion valve <NUM>, and is expanded by the expansion valve <NUM> to thereby change into two-phase refrigerant including low-pressure gas refrigerant and liquid refrigerant. The two-phase refrigerant flows into the indoor heat exchanger <NUM>, which functions as an evaporator. The two-phase refrigerant that has flowed into the indoor heat exchanger <NUM> exchanges heat with air supplied by the indoor fan <NUM>, so that the liquid refrigerant included in the two-phase refrigerant is evaporated and thus the two-phase refrigerant turns into low-pressure gas refrigerant (single phase). As a result of this heat exchange, the air-conditioning target space is cooled. The low-pressure gas refrigerant flowing out of the indoor heat exchanger <NUM> passes through the four-way valve <NUM> and flows into the compressor <NUM>, where the refrigerant is compressed into high-temperature high-pressure gas refrigerant, and discharged from the compressor <NUM> again. The above-described cycle is repeated.

The heating operation performed by the air-conditioning apparatus <NUM> will now be described.

When the compressor <NUM> is activated, high-temperature high-pressure refrigerant in a gas state is discharged from the compressor <NUM>. After that, the refrigerant flows as indicated by the broken line arrows. The high-temperature high-pressure gas refrigerant (single phase) discharged from the compressor <NUM> passes through the four-way valve <NUM> and flows into the indoor heat exchanger <NUM>, which functions as a condenser. The high-temperature high-pressure gas refrigerant that has flowed into the indoor heat exchanger <NUM> exchanges heat with air supplied by the indoor fan <NUM>, so that the high-temperature high-pressure gas refrigerant is condensed into high-pressure liquid refrigerant (single phase). As a result of this heat exchange, the air-conditioning target space is heated.

The high-pressure liquid refrigerant flowing out of the indoor heat exchanger <NUM> flows into the expansion valve <NUM>, and is expanded by the expansion valve <NUM> to thereby change into two-phase refrigerant including low-pressure gas refrigerant and liquid refrigerant. The two-phase refrigerant flows into the outdoor heat exchanger <NUM>, which functions as an evaporator. The two-phase refrigerant that has flowed into the outdoor heat exchanger <NUM> exchanges heat with air supplied by the outdoor fan <NUM>, so that the liquid refrigerant included in the two-phase refrigerant is evaporated and thus the two-phase refrigerant turns into low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant flowing out of the outdoor heat exchanger <NUM> passes through the four-way valve <NUM> and flows into the compressor <NUM>, where the refrigerant is compressed into high-temperature high-pressure gas refrigerant, and is discharged from the compressor <NUM> again. The above-described cycle is repeated.

The indoor unit <NUM> will now be described in detail.

<FIG> is a schematic perspective view of the indoor unit <NUM>. <FIG> is a schematic perspective view of the indoor unit <NUM> when a front panel <NUM> is open. The indoor unit <NUM> will be described in detail with reference to <FIG> and <FIG>.

In <FIG> and <FIG>, a face of the indoor unit <NUM> facing a wall face K is defined as a back face, and a face opposite to the back face is defined as a front face. A face of the indoor unit <NUM> facing a ceiling T is defined as a top face, and a face opposite to the top face is defined as a bottom face. A side face of the indoor unit <NUM> at the right side in <FIG> is defined as a right side face, and a face opposite to the right side face is defined as a left side face. Components included in the indoor unit <NUM> will be described based on similar definitions of positional relationships.

As illustrated in <FIG>, the indoor unit <NUM> is mounted on, for example, the wall face K of a room R that is an air-conditioning target space. The room R includes a space surrounded by the ceiling T and the wall face K. The indoor unit <NUM> is mounted such that the back face thereof is fixed to the wall face K and the top face thereof is near the ceiling T.

As illustrated in <FIG>, the indoor unit <NUM> includes a casing <NUM> having a horizontally elongated cuboid shape. However, the shape of the casing <NUM> is not limited to a horizontally elongated cuboid shape.

The casing <NUM> has an open front side, which is covered by a front panel <NUM>. The left and right sides of the casing <NUM> are covered by side panels <NUM>. The back face of the casing <NUM> is covered by a back panel <NUM>. The bottom face of the casing <NUM> is covered by the back panel <NUM>, a bottom panel <NUM>, and vertical flow directing plates <NUM>. The top face of the casing <NUM> is covered by a top panel <NUM>.

The top panel <NUM> has a grid-shaped opening, which functions as an air inlet <NUM>. Thus, the air inlet <NUM> is formed solely at the top side of the indoor unit <NUM>, and is not visible when viewed from the front.

The front panel <NUM> constitutes a design face at the front side of the indoor unit <NUM>. The front panel <NUM> has a recess 23a that extends in a width direction of the casing <NUM> at the center in a height direction of the front panel <NUM>. The front panel <NUM> is capable of covering and exposing the front side of the casing <NUM>.

As illustrated in <FIG> and <FIG>, the casing <NUM> has an opening in a region covered by the vertical flow directing plates <NUM>, and this opening serves as an air outlet <NUM>. More specifically, the air outlet <NUM> is formed at a bottom portion of the casing <NUM> including the front and bottom sides.

A pre-filter <NUM> and an air cleaning filter <NUM> are disposed in the casing <NUM>. The pre-filter <NUM> collects large particles of dust contained in air that enters through the air inlet <NUM>. The air cleaning filter <NUM> collects small particles of dust contained in air that enters through the air inlet <NUM>.

The pre-filter <NUM> corresponds to a "first filter" according to the present invention.

The air cleaning filter <NUM> corresponds to a "second filter" according to the present invention.

<FIG> is a schematic perspective view illustrating an exemplary structure of the pre-filter <NUM> installed in the indoor unit <NUM>. <FIG> is a schematic perspective view illustrating an exemplary structure of the air cleaning filter <NUM> installed in the indoor unit <NUM>. <FIG> is a schematic diagram illustrating an exemplary internal structure of the indoor unit <NUM>. The pre-filter <NUM> and the air cleaning filter <NUM> will be described with reference to <FIG>.

The pre-filter <NUM> is removably attachable to the casing <NUM> at a location upstream of the indoor heat exchanger <NUM>. The pre-filter <NUM> includes a partially bent grid-shaped frame portion 37b and a filter portion 37c attached to the frame portion 37b. When the pre-filter <NUM> is installed in the indoor unit <NUM>, as illustrated in <FIG>, the pre-filter <NUM> is located near the front and top sides of the casing <NUM>. The frame portion 37b is partially bent so that the pre-filter <NUM> can be easily attached to the casing <NUM>.

A part of the frame portion 37b of the pre-filter <NUM> serves as an attachment portion 37a to which the air cleaning filter <NUM> is attached.

The air cleaning filter <NUM> has a greater airflow passage resistance against the flow of air than that of the pre-filter <NUM>. The air cleaning filter <NUM> has, for example, a cuboid shape. The air cleaning filter <NUM> is formed separately from the pre-filter <NUM>, and is removably retained by the attachment portion 37a of the pre-filter <NUM>. Therefore, the air cleaning filter <NUM> can be installed in the casing <NUM> without using a special component. In addition, the air cleaning filter <NUM> can be installed in the casing <NUM> simply by attaching the air cleaning filter <NUM> to the attachment portion 37a, which is provided on a portion of the pre-filter <NUM>. Thus, the air cleaning filter <NUM> can be easily installed and retained in the casing <NUM>.

The air cleaning filter <NUM> may have, for example, a honeycomb structure of an electrostatically charged material. Alternatively, the air cleaning filter <NUM> may have, for example, a pleated multilayer structure having multiple layers of an electrostatically charged material. When the air cleaning filter <NUM> has such a structure, small particles of dust contained in air that passes through the air cleaning filter <NUM> can be electrostatically attracted by the air cleaning filter <NUM>.

The material that forms the air cleaning filter <NUM>, for example, a ceramic material, may have a catalyst deposited thereon so that the air cleaning filter <NUM> additionally provides a deodorizing effect. Also, the material that forms the air cleaning filter <NUM>, for example, a ceramic material, may additionally contain an antibacterial component so that the air cleaning filter <NUM> additionally provides an antibacterial effect. These effects may be selectively provided depending on needs. The material, size, shape, etc., of the air cleaning filter <NUM> are not particularly limited, and may be determined as necessary in accordance with the structure of the indoor unit <NUM>.

As illustrated in <FIG>, an airflow passage <NUM>, through which the air inlet <NUM> and the air outlet <NUM> communicate, is formed in the casing <NUM>.

The vertical flow directing plates <NUM> are disposed in the air outlet <NUM>. Also, horizontal flow directing plates <NUM> are disposed in the airflow passage <NUM> in the region between the indoor fan <NUM> and the air outlet <NUM>.

The vertical flow directing plates <NUM> adjust the direction in which air is blown from the air outlet <NUM> in the vertical direction. When the operation is stopped, the vertical flow directing plates <NUM> cover the air outlet <NUM> and form a design face at the bottom of the indoor unit <NUM>.

The horizontal flow directing plates <NUM> are disposed upstream of the vertical flow directing plates <NUM>, and adjust the blowing direction of the air from the air outlet <NUM> in a horizontal direction.

As illustrated in <FIG>, the indoor fan <NUM> and the indoor heat exchanger <NUM> are also disposed in the casing <NUM>. The indoor heat exchanger <NUM> is disposed upstream of the indoor fan <NUM> along the airflow passage <NUM>. The indoor fan <NUM> is driven by a motor (not shown) and generates a flow of air along the airflow passage <NUM>. The indoor fan <NUM> is disposed downstream of the indoor heat exchanger <NUM> along the airflow passage <NUM>. More specifically, the indoor heat exchanger <NUM> is disposed around the indoor fan <NUM>, that is, upstream of the indoor fan <NUM>, and causes heat exchange between the refrigerant that circulates through the refrigerant circuit <NUM> and indoor air supplied by the indoor fan <NUM>.

The indoor heat exchanger <NUM> includes a bend portion 4a that is provided at a certain position in the height direction of the indoor heat exchanger <NUM> and at which the indoor heat exchanger <NUM> is bent and divided into two portions, which are upper and lower portions. The indoor heat exchanger <NUM> may have a plurality of the bend portions 4a at a plurality of positions. More specifically, one or more bend portions 4a may be provided in accordance with the arrangement, size, etc., of the indoor heat exchanger <NUM> in the casing <NUM>.

The pre-filter <NUM> is disposed upstream of the indoor heat exchanger <NUM> in the casing <NUM>, and the air cleaning filter <NUM> is attached to the pre-filter <NUM>.

A protrusion 23b that projects toward the airflow passage <NUM> is formed on an inner face of the casing <NUM> that corresponds to the recess 23a in the front panel <NUM>, that is, on the back face of the front panel <NUM>.

The recess 23a and the protrusion 23b may be formed by, for example, pressing the front panel <NUM> from the outside toward the inside. In this case, the recess 23a and the protrusion 23b can be integrally formed together on the front panel <NUM>, and formation of the protrusion 23b can be facilitated. However, the protrusion 23b may instead be formed on the back face of the front panel <NUM> without forming the recess 23a in the front panel <NUM>. In such a case, the protrusion 23b may be formed by causing a portion of the back face of the front panel <NUM> to project toward the inside of the casing <NUM>. Alternatively, the protrusion 23b may be formed as a separate component and attached to the back face of the front panel <NUM>.

The protrusion 23b may be formed to extend over the entire width of the front panel <NUM>, but is not limited to this. As described below, the protrusion 23b generates a flow of air toward the air cleaning filter <NUM>. Accordingly, the length of the protrusion 23b is not limited as long as it corresponds to the dimension of the air cleaning filter <NUM> in the width direction. The cross sectional shape of the protrusion 23b is not limited to the rectangular shape illustrated in <FIG>, and may instead be, for example, a triangle, a polygon having five of more vertices, or a smooth shape having a curved face that follows the flow of air.

When the casing <NUM> is covered by the front panel <NUM>, the protrusion 23b, the air cleaning filter <NUM>, and the bend portion 4a are roughly arranged along a straight line in the direction from the front panel <NUM> to the indoor fan <NUM>. More specifically, the protrusion 23b, the air cleaning filter <NUM>, and the bend portion 4a align along line X in <FIG>. In other words, when the indoor unit <NUM> is viewed from the front, the protrusion 23b, the air cleaning filter <NUM>, and the bend portion 4a are located on a projection of the recess 23a in a horizontal direction. The line X is a straight line that extends in the horizontal direction against the indoor unit <NUM> mounted on the wall face K. When a plurality of the bend portions 4a are provided at a plurality of positions, one of the bend portions 4a, the protrusion 23b, and the air cleaning filter <NUM> may be roughly align along a straight line.

<FIG> is a schematic diagram illustrating the manner in which air flows through the indoor unit <NUM>. The flow of air through the indoor unit <NUM> will be described with reference to <FIG>.

In <FIG>, arrows A1 to A7 indicate the flow of air in the casing <NUM>. Among these arrows, the arrows A1 to A4 indicate the flow of air in a region around the air inlet <NUM> in the casing <NUM>.

When the indoor fan <NUM> is activated, air is sucked into the casing <NUM> through the air inlet <NUM>.

A part of the air that has been sucked into the casing <NUM> through the air inlet <NUM> is supplied to an upper portion of the indoor heat exchanger <NUM> (arrows A1). The upper portion of the indoor heat exchanger <NUM> is a portion of the indoor heat exchanger <NUM> disposed above the bend portion 4a in <FIG>.

Another part of the air that has been sucked into the casing <NUM> through the air inlet <NUM> flows along the inner side of the front panel <NUM>, comes into contact with the protrusion 23b, and is directed toward the indoor heat exchanger <NUM> (arrow A2).

Another part of the air that has been sucked into the casing <NUM> through the air inlet <NUM> passes through the region between the inner side of the front panel <NUM> and the air cleaning filter <NUM>, and is supplied to a lower portion of the indoor heat exchanger <NUM> (arrow A3). The lower portion of the indoor heat exchanger <NUM> is a portion of the indoor heat exchanger <NUM> below the bend portion 4a in <FIG>.

Another part of the air that has been sucked into the casing <NUM> through the air inlet <NUM> passes through the region between the inner side of the front panel <NUM> and the air cleaning filter <NUM> and then through the air cleaning filter <NUM>, and flows toward the indoor heat exchanger <NUM> (arrow A4).

Referring to the arrow A4, the air that passes through the region between the inner side of the front panel <NUM> and the air cleaning filter <NUM> is caused to flow through the air cleaning filter <NUM> by the flow of air indicated by the arrow A2. The air that has passed through the air cleaning filter <NUM> flows toward the indoor heat exchanger <NUM>.

Also, referring to the arrow A3, the air that passes through the region between the inner side of the front panel <NUM> and the air cleaning filter <NUM> is directed toward the indoor heat exchanger <NUM> by the flow of air indicated by the arrow A2 when passing through the region between the inner side of the front panel <NUM> and the air cleaning filter <NUM>, but flows toward the lower portion of the indoor heat exchanger <NUM> without passing through the air cleaning filter <NUM>.

The air supplied to the indoor heat exchanger <NUM> passes through the indoor heat exchanger <NUM> while exchanging heat with the refrigerant that flows through the indoor heat exchanger <NUM>. Thus, the air is cooled in the cooling operation and heated in the heating operation, and then reaches the indoor fan <NUM> (arrows A5). The air that has passed through the indoor fan <NUM> or the gap between the indoor fan <NUM> and the back panel <NUM> (arrow A6) is blown forward or downward from the air outlet <NUM> (arrow A7).

As illustrated in <FIG>, the air cleaning filter <NUM> is oriented to extend in the direction of the flow of air that has entered through the air inlet <NUM>. More specifically, the air cleaning filter <NUM> is retained by the pre-filter <NUM> such that an air-receiving face of the air cleaning filter <NUM> extends in the vertical direction. Therefore, when the protrusion 23b is not provided, very little air passes through the air cleaning filter <NUM> having a high air resistance. In other words, the air that has been sucked in flows along the face of the air cleaning filter <NUM>. Although the flow of air is not impeded and the performance of the indoor heat exchanger <NUM> is not degraded since air does not pass through the air cleaning filter <NUM>, the air cleaning effect cannot be provided.

Since the protrusion 23b is provided on the back face of the front panel <NUM> of the indoor unit <NUM>, the flow of air toward the inside of the indoor unit <NUM> (arrow A2) is generated by the protrusion 23b. In other words, the protrusion 23b enables a part of the air to pass through the air cleaning filter <NUM> without greatly impeding the flow in the casing <NUM>. Thus, the indoor unit <NUM> enables the air cleaning filter <NUM> to provide the air cleaning effect with less degradation in the performance of the indoor heat exchanger <NUM>.

The bend portion 4a of the indoor heat exchanger <NUM> is disposed downstream of the air cleaning filter <NUM>. As is clear from <FIG>, the air resistance of the bend portion 4a is less than that of the main portion of the indoor heat exchanger <NUM>. Therefore, when the protrusion 23b is provided, the amount of air that flows can be increased. More specifically, although the air cleaning filter <NUM> has a high air resistance, the bend portion 4a disposed downstream thereof has a low air resistance, so that air easily flows toward the air cleaning filter <NUM> and that the air cleaning effect can be increased.

As described above, the indoor unit <NUM> includes the casing <NUM> having the air inlet <NUM> in the top face, the air outlet <NUM> in the lower portion, and the airflow passage <NUM> through which the air inlet <NUM> and the air outlet <NUM> communicate; the indoor heat exchanger <NUM> disposed in the casing <NUM>; the indoor fan <NUM> disposed downstream of the indoor heat exchanger <NUM> in the casing <NUM>; the front panel <NUM> that covers the front side of the casing <NUM>; the protrusion 23b provided on the back face of the front panel <NUM>; and the air cleaning filter <NUM> disposed between the protrusion 23b and the indoor heat exchanger <NUM> in the casing <NUM>.

Thus, according to the indoor unit <NUM>, a flow of air directed from the front panel <NUM> to the air cleaning filter <NUM> can be generated by the protrusion 23b, so that the air cleaning effect can be obtained with less degradation in the performance of the indoor heat exchanger <NUM>.

The indoor unit <NUM> is configured such that the indoor heat exchanger <NUM> includes the bend portion 4a that is provided at a certain position in the height direction and at which the indoor heat exchanger <NUM> is bent, and such that the protrusion 23b, the air cleaning filter <NUM>, and the bend portion 4a of the indoor heat exchanger <NUM> align in side view, for example, along a horizontal straight line in side view.

Thus, according to the indoor unit <NUM>, the bend portion 4a, which has a lower air resistance than does the main portion of the indoor heat exchanger <NUM>, is disposed downstream of the air cleaning filter <NUM>, so that the amount of air that flows toward the air cleaning filter <NUM> can be increased.

In addition, the indoor unit <NUM> is configured such that the pre-filter <NUM> is disposed upstream of the indoor heat exchanger <NUM>, and the air cleaning filter <NUM> is retained by a portion of the pre-filter <NUM> such that the air-receiving face thereof extends in the vertical direction.

Therefore, according to the indoor unit <NUM>, the air cleaning filter <NUM> can be easily installed and retained in the casing <NUM> without using a special component.

In addition, according to the indoor unit <NUM>, the protrusion 23b is formed integrally with the recess 23a formed in a portion of the front panel <NUM>. Therefore, the protrusion 23b can be easily formed.

Claim 1:
An indoor unit (<NUM>) of an air-conditioning apparatus (<NUM>) comprising:
a casing (<NUM>) having an air inlet (<NUM>) provided solely at a top face (<NUM>) of the casing, an air outlet (<NUM>) provided at a lower portion of the casing (<NUM>), and an airflow passage (<NUM>) through which the air inlet (<NUM>) and the air outlet (<NUM>) communicate with each other;
a fan (<NUM>) disposed in the casing (<NUM>);
a heat exchanger (<NUM>) disposed upstream in airflow of the fan (<NUM>) in the casing (<NUM>);
a first filter (<NUM>) disposed upstream in airflow of the heat exchanger (<NUM>) in the casing (<NUM>);
a front panel (<NUM>) attached at a front portion of the casing (<NUM>);
a protrusion (23b) provided at a back face of the front panel (<NUM>); and
a second filter (<NUM>) disposed behind the front panel (<NUM>) and between the protrusion (23b) and the heat exchanger (<NUM>), the second filter (<NUM>) being separate from the first filter (<NUM>),
wherein the heat exchanger (<NUM>) includes a bend portion (4a) at which the heat exchanger (<NUM>) is bent at a certain position in a height direction, and
the indoor unit being characterized by that:
the protrusion (23b), the second filter (<NUM>), and the bend portion (4a) align along a horizontal straight line in side view.