EP4310404A1

EP4310404A1 - Indoor unit and air conditioning device

Info

Publication number: EP4310404A1
Application number: EP21931581.9A
Authority: EP
Inventors: Atsushi Kono; Takuya Teramoto; Yuki UGAJIN; Koji Yamaguchi; Tetsuo Yamashita; Takashi Ikeda
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2024-01-24
Also published as: US20240077214A1; CN117043517A; JPWO2022195834A1; WO2022195834A1; EP4310404A4

Abstract

An indoor unit includes: a casing that has an air outlet and an air inlet, and inside which an air passage is formed; a cross flow fan disposed in the air passage and configured to blow out, through the air outlet, air sucked in from the air inlet; a stabilizer configured to stabilize vortex of air caused by circulation of air and generated inside the cross flow fan upon rotation thereof; and a guide wall having a surface defining an outlet side air passage being a part of the air passage, the part being in downstream of the cross flow fan, wherein the stabilizer has a first surface that defines a surface opposite to the guide wall in the outlet side air passage, and a part of the outlet side air passage is formed such that a distance in a vertical direction from the first surface to the guide wall gradually decreases toward the downstream.

Description

Technical Field

The present disclosure relates to an indoor unit including a cross flow fan, and also relates to an air-conditioning apparatus.

Background Art

An indoor unit of an air-conditioning apparatus includes a cross flow fan. Conventionally, the indoor unit has a problem in that as air is more likely to flow reversely into the indoor unit from an air outlet, surging occurs in which the air is alternately blown out and sucked in through the air outlet. Therefore, an indoor unit with an improved surging-proof ability has been proposed (see, for example, Patent Literature 1).
The indoor unit in Patent Literature 1 includes a cross flow fan disposed in a casing, and a stabilizer to form an air flow passage between the cross flow fan and an air outlet. The stabilizer has a protruding portion disposed at a longitudinal end portion of the air outlet. On an inclined surface of the protruding portion on the downstream side in the blow-out direction, a rough surface is provided on which irregularities are formed. Due to this rough surface of the stabilizer, the blown air is less likely to flow away from the stabilizer at the end portion of the air outlet. This prevents the air from flowing reversely from the air outlet, which improves the surging-proof ability.

Citation List

Patent Literature

Patent Literature 1: Japanese Patent Laid-Open No. 2018-124004

Summary of Invention

Technical Problem

In the indoor unit disclosed in Patent Literature 1, airflow that passes along the stabilizer is less likely to flow away from the stabilizer. However, as the operational load of the cross flow fan increases due to an increase in airflow resistance caused by deposition of dust on a filter and other factors, the airflow on the stabilizer side passes over the protruding portion, which results in a reduction in the volume of airflow that passes along the stabilizer. This leads to a problem in that the indoor unit cannot obtain a sufficient effect of preventing the airflow from flowing reversely into the indoor unit from the air outlet, so that the surging-proof ability is reduced.
The present disclosure has been made to solve the above problems, and it is an object of the present disclosure to provide an indoor unit and an air-conditioning apparatus in which a reduction in its surging-proof ability is lessened even when a cross flow fan is under high operational load, and to provide an air-conditioning apparatus.

Solution to Problem

An indoor unit according to one embodiment of the present disclosure includes: a casing that has an air outlet and an air inlet, and inside which an air passage is formed; a cross flow fan disposed in the air passage and configured to blow out, through the air outlet, air sucked in from the air inlet; a stabilizer configured to stabilize vortex of air caused by circulation of air and generated inside the cross flow fan upon rotation thereof; and a guide wall having a surface defining an outlet side air passage being a part of the air passage, the part being in downstream of the cross flow fan, wherein the stabilizer has a first surface that defines a surface opposite to the guide wall in the outlet side air passage, and a part of the outlet side air passage is formed such that a distance in a vertical direction from the first surface to the guide wall gradually decreases toward the downstream.
An air-conditioning apparatus according to another embodiment of the present disclosure includes: the indoor unit described above; and an outdoor unit connected to the indoor unit by pipes to form a refrigerant circuit in which refrigerant circulates. Advantageous Effects of Invention
In the indoor unit according to one embodiment of the present disclosure and the air-conditioning apparatus according to another embodiment of the present disclosure, a part of the outlet side air passage is formed such that a distance in a vertical direction from the first surface to the guide wall gradually decreases toward the downstream, thus to evenly distribute airflow in the outlet side air passage. As a result, even when the operational load of the cross flow fan increases due to an increase in airflow resistance caused by deposition of dust on a filter and other factors, a low airflow-speed region is less likely to be generated in the outlet side air passage and thus air is less likely to flow reversely from the air outlet. This can accordingly lessen a reduction in the surging-proof ability.

Brief Description of Drawings

[Fig. 1] Fig. 1 is a perspective view illustrating the external appearance of an indoor unit according to Embodiment 1.
[Fig. 2] Fig. 2 is a vertical cross-sectional schematic diagram of the indoor unit according to Embodiment 1.
[Fig. 3] Fig. 3 is an enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit according to Embodiment 1.
[Fig. 4] Fig. 4 is an enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit according to Embodiment 2.
[Fig. 5] Fig. 5 is a first enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit according to Embodiment 3.
[Fig. 6] Fig. 6 is a second enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit according to Embodiment 3.
[Fig. 7] Fig. 7 is a cross-sectional view taken along the line between the Z-Z arrows in Fig. 6.
[Fig. 8] Fig. 8 is a vertical cross-sectional schematic diagram of the indoor unit according to Embodiment 4.
[Fig. 9] Fig. 9 illustrates an example of the configuration of an air-conditioning apparatus according to Embodiment 5.

Description of Embodiments

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited by the embodiments described below. In addition, the relationship of sizes of the components in the drawings described below may differ from that of actual ones.

Embodiment 1

Fig. 1 is a perspective view illustrating the external appearance of an indoor unit 100 according to Embodiment 1. Fig. 2 is a vertical cross-sectional schematic diagram of the indoor unit 100 according to Embodiment 1.
The configuration of the indoor unit 100 according to Embodiment 1 is described below. In the descriptions below, terms that represent directions including, for example, "up," "down," "right," "left," "front," and "rear," are appropriately used for the sake of easy understanding. However, these terms are used merely for description purposes, and the embodiments are not limited by these terms. In Embodiment 1, the terms, such as "up," "down," "right," "left," "front," and "rear," are used where the indoor unit 100 is viewed from the front (viewed in the direction of arrow X in Fig. 2).
The indoor unit 100 according to Embodiment 1 is a ceiling concealed indoor unit that is installed and concealed in a ceiling. However, the indoor unit 100 is not limited thereto, but may be, for example, a wall-mounted indoor unit. As illustrated in Figs. 1 and 2, the indoor unit 100 includes a box-shaped casing 1 concealed in a ceiling, a flat plate-like cosmetic panel 2 provided at a bottom portion of the casing 1 to serve as a design surface, and a flat plate-like suction grille 3 that is rotatably attached to the cosmetic panel 2.
At a rear bottom portion of the casing 1, an air inlet 1a is formed through which room air is sucked into the casing 1. At a front bottom portion of the casing 1, an air outlet 1b is formed through which conditioned air is blown out to the outside. The air inlet 1a is covered by the suction grille 3 when the suction grille 3 is closed. The air inlet 1a is provided with a filter 7 that is a porous part configured to remove dust, bacteria, and the like from the air. Room air sucked in from the air inlet 1a passes through the filter 7 and is drawn into the casing 1. The air outlet 1b is provided with an up-down vane 9a configured to change the airflow direction within a predetermined range of the up-down direction, and left-right vanes 9b configured to change the airflow direction within a predetermined range of the left-right direction.
In the casing 1, a cross flow fan 6, a motor (not illustrated), and a heat exchanger 5 are provided. The cross flow fan 6 is disposed to be rotatable in a direction illustrated by the arrow Y in Fig. 2, and is configured to generate airflow. The motor is connected to the cross flow fan 6 and rotationally driven. The heat exchanger 5 is disposed while being inclined to the horizontal plane and the depth direction, and is configured to exchange heat between refrigerant and room air sucked into the casing 1 through the air inlet 1a by the cross flow fan 6 to produce conditioned air. In the casing 1, an air passage 20 is formed such that air passes through the heat exchanger 5 from the air inlet 1a and flows to the air outlet 1b. The heat exchanger 5 and the cross flow fan 6 are disposed in the air passage 20.
The heat exchanger 5 is made up of an upper heat exchanger 5a and a lower heat exchanger 5b. One end of the upper heat exchanger 5a is connected to one end of the lower heat exchanger 5b. The heat exchanger 5 is disposed in such a manner as to form an obtuse angle between a surface of the upper heat exchanger 5a opposite to the cross flow fan 6, and a surface of the lower heat exchanger 5b opposite to the cross flow fan 6.
Further, inside the casing 1, a drain pan 4, a stabilizer 10, and a guide wall 11 are provided. The drain pan 4 is disposed below the heat exchanger 5 in such a manner as to be opposite to the lower heat exchanger 5b in its entirety and opposite to the lower end portion of the upper heat exchanger 5a. The drain pan 4 is configured to collect drain water from the heat exchanger 5. The stabilizer 10 divides the air passage 20 into an inlet side air passage 20a located upstream of the cross flow fan 6 and an outlet side air passage 20b located downstream of the cross flow fan 6. The guide wall 11 has a surface defining the outlet side air passage 20b.
Next, the operation of the indoor unit 100 according to Embodiment 1 is described.
When the motor is rotationally driven, the cross flow fan 6 connected to the motor rotates, so that room air is sucked in from the air inlet 1a. The room air sucked in from the air inlet 1a passes through the filter 7 and is sucked into the casing 1. The room air sucked into the casing 1 passes through the heat exchanger 5 during the process of flowing through the inlet side air passage 20a. At this time, the room air exchanges heat with refrigerant and becomes conditioned. Thereafter, the conditioned air flows through the outlet side air passage 20b and is blown out through the air outlet 1b toward the room. At this time, the direction of the conditioned air, to be blown out through the air outlet 1b, is changed depending on the directions of the up-down vane 9a and the left-right vanes 9b.
Fig. 3 is an enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit 100 according to Embodiment 1.
Next, the configuration of the stabilizer 10 according to Embodiment 1 is described in detail.
The stabilizer 10 is configured to stabilize vortex of air caused by circulation of air and generated inside the cross flow fan 6 upon rotation of the cross flow fan 6. As illustrated in Fig. 3, the stabilizer 10 has a first surface 10a, a second surface 10b, and a tongue-shaped portion 10c. The first surface 10a defines a surface opposite to the guide wall 11 in the outlet side air passage 20b. The second surface 10b is opposite to the cross flow fan 6. The tongue-shaped portion 10c is provided between the first surface 10a and the second surface 10b. The tongue-shaped portion 10c is the apex of a convex portion of the stabilizer 10 that is convex toward the cross flow fan 6. The second surface 10b is formed along the outer circumference of the cross flow fan 6. A gap is formed between the second surface 10b and the cross flow fan 6. Note that the gap between the second surface 10b and the cross flow fan 6 is minimized at the most downstream location of the second surface 10b in the rotation direction of the cross flow fan 6.
The first surface 10a has a flow-reduction surface 10d formed such that the cross-sectional area of the outlet side air passage 20b is reduced from the tongue-shaped portion 10c toward the downstream. This flow-reduction surface 10d is inclined in such a manner as to gradually approach the guide wall 11 toward the downstream. Specifically, as illustrated by the dotted arrows in Fig. 3, the flow-reduction surface 10d is formed such that a distance in a vertical direction from the flow-reduction surface 10d to the guide wall 11 gradually decreases toward the downstream. Where in the vertical direction, the position of the tongue-shaped portion 10c is illustrated by a dotted line H1, the position of the lower end of the air outlet 1b is illustrated by a dotted line H2, and the intermediate position between them is illustrated by a dotted line H3, then the flow-reduction surface 10d is formed at a position upstream of the intermediate position (the dotted line H3). The reason for this is to help conditioned air to be smoothly blown out downward through the air outlet 1b. Note that forming the flow-reduction surface 10d at a position downstream of the intermediate position (the dotted line H3) makes the conditioned air less likely to be smoothly blown out downward through the air outlet 1b. As described above, due to the flow-reduction surface 10d, a part of the outlet side air passage 20b is formed such that its cross-sectional area decreases toward the downstream. Note that the flow-reduction surface 10d may be shaped into a flat surface forming a straight line in side view as illustrated in Fig. 3, or may be shaped into a curved surface forming a convex curve toward the guide wall 11 in side view.
In the manner as described above, the stabilizer 10 is provided with the flow-reduction surface 10d, thus to evenly distribute airflow in the outlet side air passage 20b. This increases the volume of airflow that passes along the stabilizer 10. As a result, even when the operational load of the cross flow fan 6 increases due to an increase in airflow resistance caused by deposition of dust on the filter 7 and other factors, a low airflow-speed region is less likely to be generated in the outlet side air passage 20b and thus air is less likely to flow reversely from the air outlet 1b. This can accordingly lessen a reduction in the surging-proof ability. In the outlet side air passage 20b, the airflow speed is lower on the downstream side in the rotation direction of the cross flow fan 6, while being higher on the upstream side in the rotation direction of the cross flow fan 6. The flow-reduction surface 10d is formed on the lower airflow-speed side, that is, on the first surface 10a of the stabilizer 10. This configuration can lessen an increase in the pressure loss, compared to the case where a flow-reduction surface with an inclination is formed on the higher airflow-speed side, that is, on the guide wall 11.
As described above, the indoor unit 100 according to Embodiment 1 includes the casing 1 that has the air outlet 1b and the air inlet 1a, and inside which the air passage 20 is formed, the cross flow fan 6 disposed in the air passage 20 and configured to blow out, through the air outlet 1b, air sucked in from the air inlet 1a, the stabilizer 10 configured to stabilize vortex of air caused by circulation of air and generated inside the cross flow fan 6 upon rotation of the cross flow fan 6, and the guide wall 11 having a surface defining the outlet side air passage 20b being a part of the air passage 20, the part being in downstream of the cross flow fan 6. The stabilizer 10 has the first surface 10a that defines a surface opposite to the guide wall 11 in the outlet side air passage 20b. A part of the outlet side air passage 20b is formed such that a distance in a vertical direction from the first surface 10a to the guide wall 11 gradually decreases toward the downstream.
In the indoor unit 100 according to Embodiment 1, a part of the outlet side air passage 20b is formed such that a distance in a vertical direction from the first surface 10a to the guide wall 11 gradually decreases toward the downstream, thus to evenly distribute airflow in the outlet side air passage 20b. As a result, even when the operational load of the cross flow fan 6 increases due to an increase in airflow resistance caused by deposition of dust on the filter 7 and other factors, a low airflow-speed region is less likely to be generated in the outlet side air passage 20b and thus air is less likely to flow reversely from the air outlet 1b. This can accordingly lessen a reduction in the surging-proof ability.
In the indoor unit 100 according to Embodiment 1, the first surface 10a has the flow-reduction surface 10d that is inclined in such a manner as to gradually approach the guide wall 11 toward the downstream.
In the indoor unit 100 according to Embodiment 1, the first surface 10a of the stabilizer 10 has the flow-reduction surface 10d that is inclined in such a manner as to gradually approach the guide wall 11 from the tongue-shaped portion 10c toward the downstream. That is, the flow-reduction surface 10d is formed on the lower airflow-speed side, that is, on the first surface 10a of the stabilizer 10. This can lessen an increase in the pressure loss, compared to the case where a flow-reduction surface with an inclination is formed on the higher airflow-speed side, that is, on the guide wall 11.

Embodiment 2

Hereinafter, Embodiment 2 will be described. The descriptions of the parts overlapping with those of Embodiment 1 will be omitted, and the same parts as or the corresponding parts to those of Embodiment 1 will be designated by the same reference numerals.
Fig. 4 is an enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit 100 according to Embodiment 2.
As illustrated in Fig. 4, the first surface 10a of the stabilizer 10 has a downstream surface 10e located downstream of the flow-reduction surface 10d. Where an angle formed between a vertical plane (a dotted line V) and a plane connecting an upstream end and a downstream end of the downstream surface 10e is defined as θ2, and an angle formed between the vertical plane (the dotted line V) and a plane connecting an upstream end and a downstream end of the flow-reduction surface 10d is defined as θ1, θ2 is smaller than θ1. Note that since θ2 is equal to 0 degrees in Fig. 4, Fig. 4 omits illustration of θ2.
In the manner as described above, the angle formed between the vertical plane (the dotted line V) and the plane connecting the upstream end and the downstream end of the downstream surface 10e is smaller than the angle formed between the vertical plane (the dotted line V) and the plane connecting the upstream end and the downstream end of the flow-reduction surface 10d, so that the outlet side air passage 20b is inclined gently on the downstream side of the flow-reduction surface 10d. As a result, this helps stabilize airflow in the outlet side air passage 20b toward the air outlet 1b, and increases the volume of airflow that passes along the stabilizer 10, which can improve the surging-proof ability.
The flow-reduction surface 10d and the downstream surface 10e are formed such that the difference between θ2 and θ1 is equal to or smaller than 20 degrees. The reason for this is that if the difference between θ2 and θ1 is too large, airflow is more likely to flow away from the stabilizer 10, and thus the airflow blown out from the cross flow fan 6 flows away from the stabilizer 10, and thereafter is more likely to hit the stabilizer 10 again, so that the pressure loss in the outlet side air passage 20b is more likely to increase. Therefore, provided that the difference between θ2 and θ1 is equal to or smaller than 20 degrees, the indoor unit 100 can allow for an increase in the pressure loss in the outlet side air passage 20b.
As described above, in the indoor unit 100 according to Embodiment 2, the first surface 10a has the downstream surface 10e located downstream of the flow-reduction surface 10d, and the angle formed between the vertical plane (the dotted line V) and the plane connecting the upstream end and the downstream end of the downstream surface 10e is smaller than the angle formed between the vertical plane (the dotted line V) and the plane connecting the upstream end and the downstream end of the flow-reduction surface 10d.
In the indoor unit 100 according to Embodiment 2, the angle formed between the vertical plane (the dotted line V) and the plane connecting the upstream end and the downstream end of the downstream surface 10e is smaller than the angle formed between the vertical plane (the dotted line V) and the plane connecting the upstream end and the downstream end of the flow-reduction surface 10d, so that the outlet side air passage 20b is inclined gently on the downstream side of the flow-reduction surface 10d. As a result, this helps stabilize airflow in the outlet side air passage 20b toward the air outlet 1b, and increases the volume of airflow that passes along the stabilizer 10, which can improve the surging-proof ability.

Embodiment 3

Hereinafter, Embodiment 3 will be described. The descriptions of the parts overlapping with those of Embodiments 1 and 2 will be omitted, and the same parts as or the corresponding parts to those of Embodiments 1 and 2 will be designated by the same reference numerals.
Fig. 5 is a first enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit 100 according to Embodiment 3. Note that in Fig. 5, the position of the end portion of the cross flow fan 6 located nearest the air outlet in the horizontal direction is illustrated by a dotted line B, the position of the tongue-shaped portion 10c is illustrated by a dotted line A, and the position of the downstream end of the flow-reduction surface 10d is illustrated by a dotted line C.
In Embodiment 3, as illustrated in Fig. 5, the end portion (the dotted line B) of the cross flow fan 6 located nearest the air outlet in the horizontal direction is positioned between the tongue-shaped portion 10c (the dotted line A) and the downstream end (the dotted line C) of the flow-reduction surface 10d in the horizontal direction. This configuration helps airflow, blown out from the cross flow fan 6, to easily approach the stabilizer 10 when the cross flow fan 6 is under normal operational load. As a result, even when the operational load of the cross flow fan 6 increases, the airflow blown out from the cross flow fan 6 is less likely to approach the guide wall 11. Therefore, a low airflow-speed region is less likely to be generated in the outlet side air passage 20b and thus air is less likely to flow reversely from the air outlet 1b. This can accordingly lessen a reduction in the surging-proof ability.
Note that in a case where the tongue-shaped portion 10c (the dotted line A) is located closer to the air outlet 1b than the end portion (the dotted line B) of the cross flow fan 6 located nearest the air outlet in the horizontal direction, airflow blown out from the cross flow fan 6 is more likely to approach the guide wall 11. As a result, when the operational load of the cross flow fan 6 increases, the airflow blown out from the cross flow fan 6 is even more likely to approach the guide wall 11. Therefore, a low airflow-speed region is more likely to be generated in the outlet side air passage 20b and thus air is more likely to flow reversely from the air outlet 1b. This results in a reduction in the surging-proof ability. In a case where the end portion (the dotted line B) of the cross flow fan 6 located nearest the air outlet in the horizontal direction is closer to the air outlet 1b than the downstream end (the dotted line C) of the flow-reduction surface 10d in the horizontal direction, airflow blown out from the cross flow fan 6 is less likely to pass along the stabilizer 10. As a result, the airflow blown out from the cross flow fan 6 flows away from the stabilizer 10, becomes turbulent, and is thus more likely to hit the stabilizer 10. This leads to an increase in the pressure loss in the outlet side air passage 20b, resulting in an increase in noise level and an increase in operational load of the cross flow fan 6.
Fig. 6 is a second enlarged vertical cross-sectional schematic diagram illustrating the relevant parts of the indoor unit 100 according to Embodiment 3. Fig. 7 is a cross-sectional view taken along the line between the Z-Z arrows in Fig. 6.
As illustrated in Figs. 6 and 7, the distance from the downstream end of the flow-reduction surface 10d to the guide wall 11 differs in the rotational axis direction of the cross flow fan 6 (hereinafter, simply referred to as "rotational axis direction"). Note that the rotational axis direction in Fig. 6 is perpendicular to the drawing. Where in the outlet side air passage 20b, a distance from the downstream end of the flow-reduction surface 10d to the guide wall 11 at opposite end portions of the outlet side air passage 20b in the rotational axis direction is defined as Lb1, and a distance from the downstream end of the flow-reduction surface 10d to the guide wall 11 at the central portion of the outlet side air passage 20b in the rotational axis direction is defined as Lb2, Lb1 is smaller than Lb2.
Due to the influence of opposite sides (not illustrated) of the casing 1 defining opposite sides of the outlet side air passage 20b, air tends to be blown out from the air outlet 1b at a slower speed at opposite end portions in the rotational axis direction than the speed at the central portion in the rotational axis direction. Thus, at opposite end portions of the outlet side air passage 20b in the rotational axis direction, a lower airflow-speed region tends to be generated, and air is more likely to flow reversely from the air outlet 1b. Accordingly, the surging-proof ability tends to be reduced. Note that if the cross-sectional area of the outlet side air passage 20b is reduced, the volume of airflow that passes along the stabilizer 10 increases and accordingly the surging-proof ability can improve. On the other hand, since the airflow blown out from the cross flow fan 6 is more likely to hit the stabilizer 10, the pressure loss increases.
In view of that, in the outlet side air passage 20b, the distance from the downstream end of the flow-reduction surface 10d to the guide wall 11 at opposite end portions of the outlet side air passage 20b in the rotational axis direction is set shorter than the distance from the downstream end of the flow-reduction surface 10d to the guide wall 11 at the central portion of the outlet side air passage 20b in the rotational axis direction. This configuration can increase the volume of airflow that passes along the stabilizer 10 at opposite ends of the outlet side air passage 20b in the rotational axis direction, while lessening an increase in the pressure loss at the central portion of the outlet side air passage 20b in the rotational axis direction. Consequently, this can lessen a reduction in the surging-proof ability, while lessening an increase in the pressure loss in the outlet side air passage 20b.
As described above, in the indoor unit 100 according to Embodiment 3, the end portion of the cross flow fan 6 located nearest the air outlet 1b in the horizontal direction is positioned between the tongue-shaped portion 10c and the downstream end of the flow-reduction surface 10d in the horizontal direction.
In the indoor unit 100 according to Embodiment 3, this configuration helps airflow, blown out from the cross flow fan 6, to easily approach the stabilizer 10 when the cross flow fan 6 is under normal operational load. As a result, even when the operational load of the cross flow fan 6 increases, the airflow blown out from the cross flow fan 6 is less likely to approach the guide wall 11. Therefore, a low airflow-speed region is less likely to be generated in the outlet side air passage 20b and thus air is less likely to flow reversely from the air outlet 1b. This can accordingly lessen a reduction in the surging-proof ability.
In the indoor unit 100 according to Embodiment 3, the distance from the downstream end of the flow-reduction surface 10d to the guide wall 11 differs in the rotational axis direction of the cross flow fan 6. This distance is shorter at each end portion in the rotational axis direction than at the central portion in the rotational axis direction.
In the indoor unit 100 according to Embodiment 3, this configuration can increase the volume of airflow that passes along the stabilizer 10 at opposite ends of the outlet side air passage 20b in the rotational axis direction, while lessening an increase in the pressure loss at the central portion of the outlet side air passage 20b in the rotational axis direction. Consequently, this can lessen a reduction in the surging-proof ability, while lessening an increase in the pressure loss in the outlet side air passage 20b.

Embodiment 4

Hereinafter, Embodiment 4 will be described. The descriptions of the parts overlapping with those of Embodiments 1 to 3 will be omitted, and the same parts as or the corresponding parts to those of Embodiments 1 to 3 will be designated by the same reference numerals.
Fig. 8 is a vertical cross-sectional schematic diagram of the indoor unit 100 according to Embodiment 4. Note that in Fig. 8, the position of the tongue-shaped portion 10c is illustrated by the dotted line A, and the end portion of the heat exchanger 5 located nearest the air outlet in the horizontal direction is illustrated by a dotted line D.
In Embodiment 4, as illustrated in Fig. 8, the end portion (the dotted line D) of the heat exchanger 5 located nearest the air outlet in the horizontal direction is positioned closer to the air outlet 1b than the tongue-shaped portion 10c (the dotted line A) in the horizontal direction. Note that the end portion (the dotted line D) of the heat exchanger 5 located nearest the air outlet in the horizontal direction may be at the same position as the tongue-shaped portion 10c (the dotted line A) in the horizontal direction. This configuration can increase the heat transfer area of the heat exchanger 5, and accordingly improve heat exchange efficiency. As the heat transfer area of the heat exchanger 5 increases, air passes through the heat exchanger 5 at a decreased speed. This lessens an increase in the pressure loss in the air passage, further can secure a sufficient margin for the stall point of the cross flow fan 6, and accordingly can lessen a reduction in the surging-proof ability.
As described above, the indoor unit 100 according to Embodiment 4 includes the heat exchanger 5 configured to exchange heat between refrigerant and air sucked in from the air inlet 1a by the cross flow fan 6. The end portion of the heat exchanger 5 located nearest the air outlet 1b in the horizontal direction is at the same position as the tongue-shaped portion 10c or is positioned closer to the air outlet 1b than the tongue-shaped portion 10c in the horizontal direction.
In the indoor unit 100 according to Embodiment 4, this configuration can increase the heat transfer area of the heat exchanger 5, and accordingly improve heat exchange efficiency. As the heat transfer area of the heat exchanger 5 increases, air passes through the heat exchanger 5 at a decreased speed. This lessens an increase in the pressure loss in the air passage, further can secure a sufficient margin for the stall point of the cross flow fan 6, and accordingly can lessen a reduction in the surging-proof ability.

Embodiment 5

Hereinafter, Embodiment 5 will be described. The descriptions of the parts overlapping with those of Embodiments 1 to 4 will be omitted, and the same parts as or the corresponding parts to those of Embodiments 1 to 4 will be designated by the same reference numerals.
Fig. 9 illustrates an example of the configuration of an air-conditioning apparatus according to Embodiment 5.
In the air-conditioning apparatus illustrated in Fig. 9, the indoor unit 100 and an outdoor unit 200 are connected by a gas refrigerant pipe 300 and a liquid refrigerant pipe 400, forming a refrigerant circuit 500 in which refrigerant circulates. The indoor unit 100 is any of those described in Embodiments 1 to 4. The outdoor unit 200 includes a compressor 201, a flow switching device 202, an outdoor heat exchanger 203, an outdoor fan 204, and an expansion device 205.
The compressor 201 is configured to suction low-temperature low-pressure refrigerant, compress the suctioned refrigerant into a high-temperature high-pressure state, and discharge the compressed high-temperature high-pressure refrigerant. The compressor 201 is, for example, an inverter compressor whose capacity is controlled by changing the operational frequency. The capacity is the volume of refrigerant to be delivered per unit time.
The flow switching device 202 is, for example, a four-way valve, and configured to change the refrigerant flow direction to switch the operation mode between cooling and heating. Note that, in place of the four-way valve, a combination of a two-way valve and a three-way valve, for example, may be used as the flow switching device 202.
The outdoor heat exchanger 203 is configured to exchange heat between outside air and refrigerant. For example, during heating operation, the outdoor heat exchanger 203 serves as an evaporator to evaporate and gasify the refrigerant. During cooling operation, the outdoor heat exchanger 203 serves as a condenser to condense and liquefy the refrigerant.
The outdoor fan 204 is provided in the vicinity of the outdoor heat exchanger 203, and is configured to supply outside air to the outdoor heat exchanger 203. The volume of air to be delivered to the outdoor fan 204 is adjusted by controlling its rotation speed. For example, as the outdoor fan 204, a centrifugal fan or a multiblade fan is used, which is driven by a motor such as a direct current (DC) fan motor or an alternating current (AC) fan motor.
The expansion device 205 is configured to reduce the pressure of refrigerant and expand the refrigerant. The expansion device 205 is, for example, an electronic expansion valve that can adjust the throttle opening degree. The expansion device 205 adjusts the opening degree to control the pressure of refrigerant that enters the heat exchanger 5 during cooling operation, and control the pressure of refrigerant that enters the outdoor heat exchanger 203 during heating operation.
As described above, the air-conditioning apparatus according to Embodiment 5 includes the indoor unit 100 described in any of Embodiments 1 to 4, and the outdoor unit 200 connected to the indoor unit 100 by pipes to form the refrigerant circuit in which refrigerant circulates.
The air-conditioning apparatus according to Embodiment 5 includes the indoor unit 100 described in any of Embodiments 1 to 4, and therefore can obtain the same effects as those obtained by the indoor unit 100 described in any of Embodiments 1 to 4.

Reference Signs List

1: casing, 1a: air inlet, 1b: air outlet, 2: cosmetic panel, 3: suction grille, 4: drain pan, 5: heat exchanger, 5a: upper heat exchanger, 5b: lower heat exchanger, 6: cross flow fan, 7: filter, 9a: up-down vane, 9b: left-right vane, 10: stabilizer, 10a: first surface, 10b: second surface, 10c: tongue-shaped portion, 10d: flow-reduction surface, 10e: downstream surface, 11: guide wall, 20: air passage, 20a: inlet side air passage, 20b: outlet side air passage, 100: indoor unit, 200: outdoor unit, 201: compressor, 202: flow switching device, 203: outdoor heat exchanger, 204: outdoor fan, 205: expansion device, 300: gas refrigerant pipe, 400: liquid refrigerant pipe, 500: refrigerant circuit

Claims

An indoor unit comprising:
a casing that has an air outlet and an air inlet, and inside which an air passage is formed:
a cross flow fan disposed in the air passage and configured to blow out, through the air outlet, air sucked in from the air inlet;

a stabilizer configured to stabilize vortex of air caused by circulation of air and generated inside the cross flow fan upon rotation thereof; and

a guide wall having a surface defining an outlet side air passage being a part of the air passage, the part being in downstream of the cross flow fan, wherein

the stabilizer has a first surface that defines a surface opposite to the guide wall in the outlet side air passage, and

a part of the outlet side air passage is formed such that a distance in a vertical direction from the first surface to the guide wall gradually decreases toward the downstream.
The indoor unit of claim 1, wherein the first surface
has a flow-reduction surface that is inclined in such a manner as to gradually approach the guide wall toward the downstream.
The indoor unit of claim 2, wherein
the first surface has a downstream surface located downstream of the flow-reduction surface, and

an angle formed between a vertical plane and a plane connecting an upstream end and a downstream end of the downstream surface is smaller than an angle formed between the vertical plane and a plane connecting an upstream end and a downstream end of the flow-reduction surface.
The indoor unit of claim 2 or 3, wherein
a distance from the downstream end of the flow-reduction surface to the guide wall differs in a rotational axis direction of the cross flow fan, and

the distance is shorter at an end portion in the rotational axis direction than at a central portion in the rotational axis direction.
The indoor unit of any one of claims 2 to 4, wherein the stabilizer
has a tongue-shaped portion that is an apex of a convex portion of the stabilizer toward the cross flow fan.
The indoor unit of claim 5, wherein an end portion of the cross flow fan located nearest the air outlet in a horizontal direction
is positioned between the tongue-shaped portion and the downstream end of the flow-reduction surface in a horizontal direction.
The indoor unit of claim 5 or 6, further comprising a heat exchanger configured to exchange heat between refrigerant and air sucked in from the air inlet by the cross flow fan, wherein
an end portion of the heat exchanger located nearest the air outlet in a horizontal direction

is at a same position as the tongue-shaped portion or is positioned closer to the air outlet than the tongue-shaped portion in a horizontal direction.
An air-conditioning apparatus comprising:
the indoor unit of any one of claims 1 to 7; and

an outdoor unit connected to the indoor unit by pipes to form a refrigerant circuit in which refrigerant circulates.