EP2775226B1

EP2775226B1 - Indoor unit of air-conditioner

Info

Publication number: EP2775226B1
Application number: EP14154394.2A
Authority: EP
Inventors: Naoyuki Fushimi; Hajime Sasaki; Kazuho Hirao; Naoki Muramatsu
Original assignee: Hitachi Johnson Controls Air Conditioning Inc
Current assignee: Hitachi Johnson Controls Air Conditioning Inc
Priority date: 2013-03-06
Filing date: 2014-02-07
Publication date: 2018-05-09
Anticipated expiration: 2034-02-07
Also published as: EP2775226A2; JP2014173738A; EP2775226A3; JP5891190B2

Description

Technical Field

The present invention relates to an indoor unit of an air-conditioner and this is especially suitable for an in-ceiling type indoor unit. An indoor unit of an air-conditioner as described in the preamble portion of patent claim 1 has been known from JP-2008-101868 A .

Background Art

The indoor unit of the air-conditioner is configured to perform indoor air conditioning by drawing an indoor air flow through an air inlet, cooling the air flow by allowing the same to pass through a heat exchanger, and blowing the cooled air flow into a room through an air outlet. A wind direction adjusting louver (wind direction plate) is installed on the air outlet of such air-conditioner such that an air outlet direction of the air flow may be changed.
JP 2012-97958 A , for example, discloses this type of conventional art. JP 2012-97958 A discloses an air-conditioner capable of preventing dew condensation by eliminating a temperature difference between front and rear surfaces of the wind direction plate by allowing uniform temperature-regulated air flow (cold air) to flow on both surfaces of the wind direction plate. That is to say, JP 2012-97958 A discloses an air-conditioner provided with a jump ramp which allows a flow of air to flow toward an opposite side of a wind-receiving surface of the wind direction plate on a side wall of an air passage on a side opposed to the wind-receiving surface of the wind direction plate, the jump ramp provided with a ventilation opening which allows the flow of air to flow toward a side of the wind-receiving surface of the wind direction plate.
JP 2008-101868 A discloses an indoor unit of an air-conditioner, comprising: a casing embedded in a ceiling; a decorative air panel provided on a bottom surface of the casing; a blower and a heat exchanger provided within the casing; an air inlet for drawing an indoor air flow into the casing; an air outlet for blowing an air flow into a room; and a louver provided on the air outlet for adjusting a wind direction of an outlet air flow, wherein the louver has a cross-sectional shape formed of circular arcs with two or more curvature radii.

Summary of Invention

Technical Problem

In JP 2012-97958 A described above, it is configured to send the temperature-regulated air flow to a rear portion of the louver by providing the jump ramp and allow the temperature-regulated air flow to flow on a design surface side (opposed side of the wind-receiving surface) of the louver, thereby preventing the dew condensation.
Although the air outlet of the indoor unit is formed of a foamed polystyrene member in general, since the jump ramp cannot be integrally formed with the foamed polystyrene member forming the air outlet, it is necessary to manufacture the same as another member and attach the same to the foamed polystyrene member with an adhesive and the like, so that this increases a cost. Furthermore, if the jump ramp is provided on the air outlet, a flow passage of the air outlet becomes narrower, so that an air volume problematically decreases.
The wind direction adjusting louver installed on the air outlet of the indoor unit of the air-conditioner is configured to change a direction of the outlet air flow from a substantially vertical direction to a substantially horizontal direction. In contrast, the air passage on an upstream side of the air outlet of the indoor unit is a flow downward (vertical direction), and especially, when the outlet air flow is set to be blown in the substantially horizontal direction by the louver, the temperature-regulated air flow (cold air) is less likely to flow on the design surface side on a front side (tip end side) of the louver. Therefore, it is understood that there is a problem that a region (separated region) through which the cold air does not flow occurs on the design surface side on the front side of the louver and the indoor air flow enters the region and the dew condensation occurs. JP 2012-97958 A and JP 2008-101868 A described above do not consider about this problem.
An object of the present invention is to obtain the indoor unit of the air-conditioner capable of inhibiting the occurrence of the dew condensation on the design surface side of the louver even when the outlet air flow is blown in the substantially horizontal direction.

Solution to Problem

The above-described object is accomplished, according to the present invention, by an indoor unit of an air-conditioner, which has the features of patent claim 1.
Dependent claims are directed on features of preferred embodiments of the invention.

Advantageous Effect of Invention

According to the present invention, there is an effect of obtaining the indoor unit of the air-conditioner capable of inhibiting the occurrence of the dew condensation on the design surface side of the louver even when the outlet air flow is blown in the substantially horizontal direction.

Brief Description of Drawings

FIG. 1 is a vertical cross-sectional view of a first embodiment of an indoor unit of an air-conditioner of the present invention.
FIG. 2 is an enlarged cross-sectional view of a substantial part for illustrating a shape of a louver and a flow of air around the same in the indoor unit of a conventional air-conditioner.
FIG. 3 is an enlarged cross-sectional view of a substantial part of a state in which the louver illustrated in FIG. 2 is fully closed.
FIG. 4 is an enlarged cross-sectional view of a substantial part for illustrating the flow of air around the louver having an initially studied louver shape.
FIG. 5 is an enlarged cross-sectional view of a substantial part of a state in which the louver illustrated in FIG. 4 is oriented in a substantially vertical direction to realize vertical outlet.
FIG. 6 being an enlarged cross-sectional view of a substantial part of a configuration in the vicinity of an air outlet in the first embodiment of the present invention is a view for illustrating the flow of air around the louver.
FIG. 7 is an enlarged cross-sectional view of a substantial part of a state in which the louver illustrated in FIG. 6 is oriented in the substantially vertical direction to realize the vertical outlet.
FIG. 8 being an enlarged view of the louver illustrated in FIG. 6 is a view for illustrating a shape of the louver.
FIG. 9B is a diagram for illustrating an air volume on a design surface side of a louver tip end in a horizontal outlet state (FIG. 9A) in the first embodiment of the present invention.
FIG. 10B is a diagram illustrating a total air volume blown through the air outlet in a downward outlet state (FIG. 10A) in the first embodiment of the present invention.

Description of Embodiments

A specific embodiment of the present invention is hereinafter described with reference to the drawings. Meanwhile, in each drawing, a part to which the same reference sign is assigned indicates an identical or equivalent part.

First Embodiment

FIG. 1 being a vertical cross-sectional view of an indoor unit of an air-conditioner of the first embodiment illustrates an example in which the present invention is applied to an in-ceiling type indoor unit.
An indoor unit 1 includes a main body 1a embedded in a ceiling 11 and a decorative air panel 1b covering an opening on a lower surface of the main body 1a. The decorative air panel 1b is provided with an air inlet 2 through which an indoor air flow is drawn and an air outlet 4 through which an air flow (conditioned air flow) conditioned by a heat exchanger 3 installed within the main body 1a is blown into a room. A louver 7 which makes an air outlet direction of the air flow changeable is pivotally supported by the air outlet 4 at end portions in a longitudinal direction thereof so as to be rotatable.
A length of the louver 7 in the air outlet direction is made relatively long such that the louver 7 in a closed state may substantially block the air outlet 4 (substantially the same length as a width of the air outlet) for aesthetic purposes on a side of a design surface of the decorative air panel 1b and for improved wind direction controllability of an outlet air flow. The louver 7 in this embodiment is configured so as to be able to change a wind direction of the outlet air flow from a substantially vertical direction to a substantially horizontal direction.
An air passage 6 communicating with the air inlet 2 and the air outlet 4 is formed within a casing 10 forming the main body 1a of the indoor unit 1, in the middle of which an air blower 8 and the heat exchanger 3 are installed. It is configured such that, when the air blower 8 is rotary-driven, the indoor air flow is drawn through the air inlet 2, and the drawn air flow passes through the heat exchanger 3 and thereafter sent toward the air outlet 4 to be blown into the room.
The heat exchanger 3 in which a cooling medium flowing therein forms a refrigeration cycle is configured to operate as an evaporator at the time of cooling and operate as a condenser at the time of heating, and to generate warm air or cold air by heat exchange with the drawn air flow. The heat exchanger 3 is installed on a drain pan 5 and the drain pan 5 is configured to temporarily store drain water dropped from the heat exchanger 3.
It is configured such that the air flow cooled, for example, by passage through the heat exchanger 3 passes through the air passage 6 formed of the drain pan 5 and a heat insulating material 9 provided on an inner surface of the casing 10 to be blown through the air outlet 4 after the air outlet direction thereof is adjusted by the louver 7.
Herein, a conventional structure of the louver 7 is first described with reference to FIGS. 2 and 3. FIG. 2 is an enlarged cross-sectional view of a substantial part for illustrating a shape of the louver and a flow of air around the same of the indoor unit of a conventional air-conditioner, and FIG. 3 is an enlarged cross-sectional view of a substantial part of a state in which the louver illustrated in FIG. 2 is fully closed.
The conventional normal louver 7 has the shape as illustrated in FIGS. 2 and 3. That is to say, as illustrated in FIG. 3, a curvature of the louver 7 on the design surface side is often made similar to a curvature of a surface of the decorative air panel 1b in a portion of the air outlet 4 in consideration of design when the louver 7 is closed. The flow of air in the vicinity of the air outlet 4 in the conventional indoor unit 1 provided with the louver having such shape is described with reference to FIG. 2.
FIG. 2 illustrates the flow of air when the wind direction of the outlet air flow is in the substantially horizontal direction (horizontal outlet state). In a case of cooling operation, cold air (conditioned air flow) 12 passing through the air passage 6 is branched into a flow (branched flow) 12a on a side of a pressure surface of the louver 7 and a flow (branched flow) 12b on an opposite side of the pressure surface (design surface side) with a rear side (upstream side) end portion of the louver 7, that is to say, a portion of a rear end 7a as a branching point. The branched flow 12b briefly flows in a direction opposite to the air outlet direction (direction to the center of the indoor unit) by resistance of the rear end 7a of the louver 7. Therefore, this cannot flow along the design surface side of the louver 7 and a region in which the cold air does not flow along a louver surface, that is to say, a separated region 13 occurs. It is understood that, when the indoor air flow with high humidity enters the separated region 13, this is brought into contact with the louver 7 cooled by the cold air and dew condensation problematically occurs.
An initially studied plan for solving the problem is described with reference to FIGS. 4 and 5. FIG. 4 is an enlarged cross-sectional view of a substantial part for illustrating the flow of air around the louver having an initially studied louver shape, and FIG. 5 is an enlarged cross-sectional view of a substantial part of a state in which the louver illustrated in FIG. 4 is oriented in the substantially vertical direction to realize vertical outlet.
In the louver shape illustrated in FIGS. 4 and 5, a curvature radius of the louver is made small. FIG. 4 illustrates the flow of air when the wind direction of the outlet air flow is in the substantially horizontal direction (horizontal outlet state) with the rear end 7a of the louver 7 oriented upward. Although the cold air 12 passing through the air passage 6 is branched into the branched flow 12a on the side of the pressure surface of the louver 7 and the branched flow 12b on the opposite side of the pressure surface with the portion of the rear end 7a of the louver 7 as the branching point in this case also, the outlet air flow is smoothly branched at the rear end 7a of the louver 7 and the branched flow 12b does not flow in the direction opposite to the air outlet direction but flows along the design surface side of the louver 7.
However, due to the small curvature radius, the Coanda effect by which the outlet air flow (branched flow 12b) flows along the opposite side of the pressure surface of the louver 7 does not sustain to a louver tip end, so that the outlet air flow is separated in the vicinity of a tip end 7b of the louver 7 and the separated region 13 also occurs as represented by a reference sign 13 in FIG. 4. Although the separated region 13 is smaller than the separated region in a case of the conventional louver shape illustrated in FIG. 2, as in the case in FIG. 2, the indoor air flow with high humidity enters the separated region 13 to be brought into contact with the cooled louver 7 and the dew condensation occurs.
Also, as illustrated in FIG. 5, in a state in which the louver 7 is oriented in the substantially vertical direction to blow downward (downward outlet state), due to the small curvature radius of the louver 7, the outlet air flow is less likely to flow along the side of the pressure surface (inner side) of the louver 7, and a region 14 in which the air flow flows with difficulty in FIG. 5 occurs. This has the same meaning as a narrow air passage 6 or air outlet 4 and this causes decrease in air volume due to increase in ventilation resistance.
Furthermore, in this example, due to the small curvature radius of the louver 7, there also is a problem that the tip end 7b of the louver 7 is also oriented upward at the time of the horizontal outlet state as illustrated in FIG. 4, smudging in which an outlet air flow 12c blown through the air outlet 4 flows in a direction toward the ceiling 11 occurs, and a ceiling surface gets dirty.
Next, the louver shape in the indoor unit of this embodiment illustrated in FIG. 1 is described with reference to FIGS. 6 to 8. FIG. 6 being an enlarged cross-sectional view of a substantial part of a configuration in the vicinity of the air outlet in the first embodiment of the present invention is a view for illustrating the flow of air around the louver, FIG. 7 is an enlarged cross-sectional view of a substantial part of a state in which the louver illustrated in FIG. 6 is oriented in the substantially vertical direction to realize the vertical outlet, and FIG. 8 being an enlarged view of the louver illustrated in FIG. 6 is a view for illustrating the louver shape.
FIG. 6 illustrates the flow of air when the wind direction of the outlet air flow is in the substantially horizontal direction (horizontal outlet state) with the rear end 7a of the louver 7 oriented upward. In this embodiment also, the cold air 12 passing through the air passage 6 is branched into the branched flow 12a on the side of the pressure surface of the louver 7 and the branched flow 12b on the opposite side of the pressure surface with the portion of the rear end 7a of the louver 7 as the branching point, but the outlet air flow is smoothly branched at the rear end 7a of the louver 7 and the branched flow 12b does not flow in the direction opposite to the air outlet direction but flows along the design surface side of the louver 7.
That is to say, in the louver 7 of this embodiment, the rear end 7a of the louver 7 is oriented upward in order to realize smooth branching of the outlet air flow at the louver rear end 7a in the horizontal outlet state. In order to prevent separation of the outlet air flow (cold air) on the design surface side (opposite side of the pressure surface) on a side of the louver tip end 7b and prevent the occurrence of the smudging in which the outlet air flow flows in the direction toward the ceiling 11 and the ceiling surface gets dirty, a shape of a front side portion of the louver 7 is made different from a shape of a rear side portion to obtain a forward-backward asymmetric shape. According to this, the separation of the cold air on the design surface side of the louver 7 is prevented, and the occurrence of the dew condensation is inhibited.
FIG. 7 illustrates the flow of air in a state in which the louver 7 is oriented in the substantially vertical direction and the wind direction of the outlet air flow is in the substantially vertical direction (downward outlet state) in the indoor unit of this embodiment. As illustrated in FIG. 7, in this embodiment, the wind easily flows along the side of the pressure surface (inner side) of the louver 7 also in the downward outlet state, so that the region 14 in which the air flow flows with difficulty as illustrated in FIG. 5 does not occur or this is extremely small as represented by a reference sign 14 in FIG. 7 even if this occurs. Therefore, the ventilation resistance in the air passage 6 and the air outlet 4 may be made small, so that it is also possible to prevent decrease in total air volume blown through the air outlet 4.
A detailed shape of the louver 7 in this embodiment is described with reference to FIG. 8. A cross-sectional shape of the louver 7 of this embodiment is formed of circular arcs 30 and 31 with two curvature radii R1 and R2, respectively. Meanwhile, it is also possible to form the louver 7 of circular arcs with three or more curvature radii. In this embodiment, the louver 7 is formed such that the curvature radius R2 forming the rear side portion of the louver 7 is smaller than the curvature radius R1 forming the front side portion of the louver 7.
An angle between a tangent 32 at the louver tip end 7a of the circular arc 30 with the curvature radius R1 forming the front side portion of the louver 7 and a level line (a line indicating level line 34) in a fully-closed state as illustrated in FIG. 8 is set to an angle A. An angle between a tangent 33 at the louver rear end 7b of the circular arc 31 with the curvature radius R2 forming the rear side portion of the louver 7 and the level line (the line indicating level line 34) is set to an angle B.
In the conventional normal louver shape, "B/A = 1" is satisfied in general. In contrast, the louver shape of this embodiment illustrated in FIG. 8 is configured to satisfy "B/A ≈ 3". Meanwhile, the shape of the louver in this embodiment may be in a range of "B/A = 2 to 4". A reason for this is hereinafter described with reference to FIGS. 9 and 10.
FIG. 9A is a view of the louver having the shape illustrated in FIG. 8 in the horizontal outlet state, and FIG. 9B illustrates the air volume in a part 15 on the design surface side of the louver tip end with respect to the louver shape B/A in the state illustrated in FIG. 9A. It is indicated that, the larger the air volume in the part 15 is, the more the outlet air flow flows along the louver, so that the dew condensation is less likely to occur, that is to say, dew condensation proof is higher. The air volume in the part 15 tends to be larger when B/A of the louver shape is larger, and the air volume is the largest when "B/A = 4" is satisfied. It is also understood that the air volume significantly decreases with the conventional louver shape (B/A = 1) and the dew condensation easily occurs. From FIG. 9B, it is understood that the occurrence of the dew condensation may be inhibited when B/A is set to 2 or larger and especially, the occurrence of the dew condensation may be significantly inhibited when this is set to 3 or larger.
FIG. 10A is a view of the louver having the shape illustrated in FIG. 8 in the downward outlet state, and FIG. 10B illustrates the total air volume blown through the air outlet 4 with respect to the louver shape B/A in the state illustrated in FIG. 10A. It is indicated that, the larger the total air volume is, the smaller the ventilation resistance at the air outlet 4 is, so that pressure loss is smaller. The total air volume tends to be smaller as B/A of the louver shape is larger. That is to say, it is understood that, in the downward outlet state of the louver, the louver 7 does not block the air passage 6 and the air outlet 4 when the louver shape B/A is smaller, so that the total air volume increases. From FIG. 10B, B/A is preferably set to 4 or smaller.
From a result of FIGS. 9 and 10 described above, it is understood that the occurrence of the dew condensation may be inhibited even in the horizontal outlet state of the louver and decrease in total air volume may be inhibited even in the downward outlet state of the louver when
B/A = 2 to 4 of the louver shape B/A is satisfied. Therefore, the louver shape B/A may be set to 2 to 4 and preferably set to approximately 3 (2.5 to 3.2).
As described above, according to this embodiment, since the angle of the louver rear portion relative to the level line is made larger than that of the front portion, specifically, the louver shape B/A is set to 2 to 4, it is possible to allow the cold air (conditioned air flow) to flow along the design surface side of the louver even in the horizontal outlet state in which the outlet air flow is blown in the substantially horizontal direction, so that the indoor unit of the air-conditioner capable of inhibiting the occurrence of the dew condensation on the design surface side of the louver may be obtained. In addition, according to this embodiment, the dew condensation may be prevented without providing a member such as a jump ramp disclosed in PTL 1, and further, it is possible to prevent the ceiling surface from getting dirty by the smudging. According to this embodiment, an effect of minimizing the decrease in total air volume even in the downward outlet state of the outlet air flow may also be obtained.
Meanwhile, the present invention is not limited to the above-described embodiment and various modifications may be included. For example, although a case in which the present invention is applied to a one-way outlet type indoor unit which draws the indoor air flow from a lower surface on a rear side of the indoor unit 1 and blows the conditioned air flow from the lower surface on a front side of the indoor unit 1 is described in this embodiment, this may also be similarly applied to a four-way outlet type indoor unit which draws the indoor air flow from the lower surface on the center of the indoor unit and blows the conditioned air flow from four portions on the lower surface on an outer peripheral side of the indoor unit.

Reference Signs List

1 indoor unit, 1a main body, 1b decorative air panel, 2 air inlet, 3 heat exchanger, 4 air outlet, 5 drain pan, 6 air passage, 7 louver, 7a tip end, 7b rear end, 8 blower, 9 heat insulating material, 10 casing, 11 ceiling, 12 cold air (conditioned air flow), 12a, 12b branched flow, 12c outlet air flow, 13 separated region, 14 region in which air flow flows with difficulty, 15 part on design surface side of louver tip end, 30, 31 circular arc, 32, 33 tangent, 34 line indicating level line.

Claims

An indoor unit (1) of an air-conditioner, comprising:
a casing (10) embedded in a ceiling (11); a decorative air panel (1b) provided on a bottom surface of the casing (10); a blower (8) and a heat exchanger (3) provided within the casing (10); an air inlet (2) for drawing an indoor air flow into the casing (10); an air outlet (4) for blowing an air flow into a room; and a louver (7) provided on the air outlet (4) for adjusting a wind direction of an outlet air flow, wherein

the louver (7) has a cross-sectional shape formed of circular arcs (30, 31) with two or more curvature radii (R1, R2),

characterized in that the louver (7) is formed such that louver shape B/A is in a range of $B / A = 2 to 4$

if an angle (A) between a tangent (32) at a louver tip end (7b) of the circular arc (30) forming a front side portion of the louver (7) and a level line (34) is set to A and an angle (B) between a tangent (33) at a louver rear end (7a) of the circular arc (31) forming a rear side portion of the louver (7) and the level line (34) is set to B in a fully-closed state of the louver (7), and wherein the louver (7) is configured in such a shape that the rear end (7a) of the louver (7) is oriented upward facing the upper air passage (6) when the wind direction of the outlet air flow is in the horizontal direction.
The indoor unit (1) of the air-conditioner according to claim 1, characterized in that the louver (7) is formed such that a curvature radius (R2) forming the rear side portion of the louver (7) is smaller than a curvature radius (R1) forming the front side portion of the louver (7) .
The indoor unit (1) of the air-conditioner according to claim 1, characterized in that the louver (7) is configured to be able to change a wind direction of the outlet air flow from a substantially vertical direction to a substantially horizontal direction.
The indoor unit (1) of the air-conditioner according to any one of claims 1 to 3, characterized in that the louver (7) is formed such that the louver shape B/A is in a range of $B / A = 2.5 to 3.2.$
The indoor unit (1) of the air-conditioner according to any one of claims 1 to 3, characterized in that a length of the louver (7) in an air outlet direction is set such that the louver (7) is capable of substantially blocking the air outlet (4) when being closed.