INDOOR UNIT FOR AIR CONDITIONING APPARATUS

Abstract

An indoor unit for an air conditioning apparatus is provided. The indoor unit includes a cross flow fan having a structure that can reduce noise and flow resistance of air passing through a heat exchanger in the indoor unit.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This claims the priority to Korean Patent Application No. 10-2008-0117860 (filed in Korea on Nov. 26, 2008), the entirety of which is incorporated herein by reference.

BACKGROUND

1. Field

An air conditioning system is provided, and in particular an indoor unit for an air conditioning system is provided.

2. Background

In general, an air conditioning apparatus cools/heats a room using a compressor, a condenser, an expander, and an evaporator. The air conditioning apparatus may be a separated-type air conditioning apparatus in which an indoor unit is separated from an outdoor unit, or an integrated-type air conditioner in which an indoor unit is integrated with an outdoor unit. Improvements in efficiency, effectiveness and noise level during operation are desirable in either type of air conditioning apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, wherein:

FIG. 1 is a side cross-sectional view of a structure of an indoor unit for an air conditioning apparatus according to an embodiment as broadly described herein;

FIG. 2 is a front perspective view of a chassis of the indoor unit shown in FIG. 1;

FIG. 3 is a partial perspective view of a fan of the indoor unit shown in FIG. 1;

FIG. 4 is a side view of the fan shown in FIG. 3;

FIG. 5 is a perspective view of a blade corresponding to a portion A of FIG. 4;

FIG. 6 is a graph of a relationship between an outer circumferential angle and noise in a fan of an indoor unit according to an embodiment as broadly described herein;

FIG. 7 is a graph of a relationship between a ratio of inner diameter to outer diameter and noise in a fan of an indoor unit according to an embodiment as broadly described herein;

FIG. 8 is a graph of a relationship between a ratio of thickness to length of a fan and noise in a fan of an indoor unit according to an embodiment as broadly described herein;

FIG. 9 is a graph of a relationship between a ratio of an insertion depth to length of a fan and noise in a fan of an indoor unit according to an embodiment as broadly described herein; and

FIG. 10 is a graph of noise performance improvement of an indoor unit including a fan and an indoor unit as embodied and broadly described herein.

DETAILED DESCRIPTION

In a separated air conditioning apparatus, a fan and a heat exchanger that performs a heat exchange operation with indoor air drawn in by the fan may be received in the indoor unit. Air may flow from, for example, a front upper surface of the indoor unit downward to be discharged at a lower portion of the front surface of the indoor unit. A high efficiency cross flow fan may be installed in an indoor unit that is installed on a wall surface to reduce power consumption.

A heat exchanger that has an increased heat exchange area may also be used to improve efficiency. Such a heat exchanger may include coolant pipes arranged in 3 rows forward and backward. However, if this type of 3 row heat exchanger is used in an indoor unit in combination with a cross flow fan, system resistance may be increased. As system resistance is increased, the noise level at a given air flow rate may also be increased. For example, a surging noise may be generated. A structure in which the fan may be operated at a desired level without generating abnormal noise would be beneficial, especially when air resistance is increased due to dust accumulated on a heat exchanger or a filter after extended use, and a 3 row heat exchanger and cross flow fan are used.

FIG. 1 is a side cross-sectional view of an indoor unit 10 for an air conditioning apparatus, including a chassis 11 that may be closely adhered to a support surface, such as, for example, a wall, a front frame 12 that is coupled to a front side of the chassis 11, a front panel 13 that is rotatably or slidably provided on a front surface of the front frame 12, a fan 17 that is received in a space formed by the chassis 11 and the front frame 12 to draw indoor air into the indoor unit 10, and a heat exchanger 16 that surrounds the fan 17 to perform a heat exchange operation with the indoor air.

A stabilizer 112 may be provided on a front surface of the chassis 11 to allow air flow to be generated as the fan 17 rotates. A heat exchanger seating part 111 that supports a first end of the heat exchanger 16 may be formed on an upper side of the stabilizer 112. An inlet grill 121 may be formed on an upper surface of the front frame 12 to guide the flow of indoor air into the indoor unit 10, and a front surface inlet port 122 may be formed on a front surface of the front frame 12. A filter 15 may be mounted on a front surface of the heat exchanger 16 to filter indoor air drawn in through the inlet grill 121 and the front surface inlet port 122.

As the indoor unit 10 operates, an upper end or a lower end of the front panel 13 may be rotated away from the front frame 12 or may be moved vertically relative to the front frame 12 to allow the front surface inlet port 122 to be opened or exposed. A discharge grill 14 may be provided on a lower end of the indoor unit 10 so that a second end of the heat exchanger 16 may be seated on an upper side of the discharge grill 14. An air outlet port 141 may be formed on a lower side of the discharge grill 14. A lower end of the stabilizer 112 may extend to the air outlet port 141. A discharge louver 143 that controls a leftward and rightward flow of discharged air and a discharge vane 142 that not only selectively opens/closes the air outlet port 141 but also controls an upward and downward flow of the discharged air may each be provided on the air outlet port 141. The discharge vane 142 and the discharge louver 143 may be rotatably coupled to each other on a lower side of the discharge grill 14. In certain embodiments, the heat exchanger 16 may have a shape in which coolant pipes are arranged in 3 rows from front to back or are divided into plural sections so as to surround a front and an upper portion of the fan 17, and the fan 17 may be a cross flow fan.

FIG. 2 is a front perspective view of the chassis shown in FIG. 1. In the embodiment shown in FIG. 2, the heat exchanger seating part 111 and the stabilizer 112 are formed on the front surface of the chassis 11, and a fan supporter 114 is provided at a first end of the chassis 11, along a corresponding end of the stabilizer 112. A motor seating part 113 is provided on a side of the fan supporter 114 to support a motor that drives the fan 17. A fan insertion groove 115 may be formed at a second end of the chassis 11 opposite the first end. The fan insertion groove 115 may have a predetermined depth t, or thickness, to support the corresponding end of the fan 17.

Fan noise may be generated differently depending on the extent to which the fan insertion groove 115 extends into the chassis 11, its thickness or depth t, and its shape. Therefore, the depth t of the fan insertion groove 115 may be one design factor to consider for reducing noise of the indoor unit 10. Hereinafter, the relationship between the depth t of the fan insertion grove 115 and noise, and determination of an appropriate depth t of the fan insertion groove 115 will be explained.

Referring to FIGS. 3 and 4, the fan 17 included with an indoor unit 10 as embodied and broadly described herein may be a cross flow fan, and the cross flow fan may include a plurality of blades 171 that are radially arranged in a circumferential direction. Each blade 171 may be slanted at a predetermined angle θ, such that a line that extends along a width s (see FIG. 5) direction of each blade is not parallel to a rotation shaft of the fan 17, but instead is slanted by the predetermined angle θ. The fan 17 defines a mean camber line by means of an inner diameter D1 from a center to an inner end, or root end, of the blade 171, an outer diameter D2 from a center to an outer end, or tip end, of the blade 171, an inner circumferential angle β1 and an outer circumferential angle β2. The mean camber line of the blade 171 (hereinafter, referred to as a camber line) is a line that bisects a thickness T of the blade 171, essentially following the contour of the blade.

The inner circumferential angle β1 is an angle defined by a line connecting the inner end, or root end, of the camber line to the center of the fan 17 and a tangential line that passes through the inner end, or root end, of the camber line at the inner diameter D1. Hereinafter, the inner circumferential angle β1 will be set to approximately 90 degrees. The outer circumferential angle β2 is an angle is defined by a straight line that extends outward from the outer end, or tip end, of the camber line and a tangential line that passes through the outer end, or tip end, of the camber line at the outer diameter D2.

Referring to FIG. 5, the blade 171 may have a predetermined chord length L and a predetermined width s and may be somewhat rounded in the length L direction. More specifically, an inner curvature p1 of the blade 171 (at a surface of the blade 171 that is oriented toward the center of the fan 17) may be different from an outer curvature p2 thereof (at a surface of the blade 117 that is oriented away from the center of the fan 17). Therefore, a thickness of the edge portion of the blade 171 may be different from that of the central portion. In other words, the blade 171 has a shape that is thick and then becomes thin from one end to the other end. And, the length L of the blade 171 is defined based on a straight line distance from the inner, root, end of the blade 171 to the outer, tip, end thereof.

In an indoor unit 10 in which the fan 17 constituted as described above is installed, the relationship between a ratio of inner diameter D1 to outer diameter D2 of the fan 17 and noise, the relationship between an outer circumferential angle β2 and noise, the relationship between a ratio of thickness T to length L of a fan and noise, the relationship between a ratio of an insertion depth t of a side end of a fan to a length L of the fan and noise, may all be taken into consideration in reducing fan noise.

FIG. 6 is a graph of the relationship between an outer circumferential angle β2 and noise in a fan in which an inner circumferential angle β1 is set to approximately 90 degrees. As shown in FIG. 6, noise is on a downward trend and continues to be reduced until the outer circumferential angle β2 of the blade 171 reaches approximately 30 degrees and then begins to increase as it exceeds 30 degrees. Thus, noise may be minimized when the outer circumferential angle β2 is approximately 30 degrees. In certain embodiments, the outer circumferential angle β2 of the blade 171 is preferably 28 degrees≦β2≦32 degrees, and more preferably, 30 degrees≦β2≈32 degrees.

FIG. 7 is a graph of the relationship between a ratio of inner diameter to outer diameter D1/D2 and noise in a fan of an indoor unit as embodied and broadly described herein. As shown in FIG. 7, noise is on a downward trend and continues to be reduced until the ratio of inner diameter to outer diameter D1/D2 is approximately 0.79 and then increases as the ratio of inner diameter D1/D2 to outer diameter exceeds 0.79. In certain embodiments, the ratio of inner diameter to outer diameter of the blade 171 is preferably 0.77≦D1/D2≦0.81, and more preferably, 0.77≦D1/D2≦0.8.

FIG. 8 is a graph of the relationship between a ratio of thickness to length T/L of a fan blade 117 and noise in a fan of an indoor unit according to an embodiment as broadly described herein. As shown in FIG. 8, noise is on a downward trend and continues to be reduced until the ratio of thickness to length T/L reaches approximately 0.1, and then increases as the ratio of thickness to length T/L exceeds 0.1. In other words, the noise level is minimized at a point where the ratio of thickness to length T/L is approximately 0.1. In certain embodiments, the ratio of thickness to length of a fan is preferably 0.088≦T/L≦0.132.

FIG. 9 is a graph of a relationship between a ratio of an insertion depth t to length L and noise in a fan of an indoor unit according to an embodiment as broadly described herein. As shown in FIG. 9, noise is on a downward trend and continues to be reduced until the ratio of an insertion depth to length t/L reaches approximately 0.007, and then increases as the ratio of an insertion depth to length t/L exceeds 0.007. In other words, the noise level is minimized at a point where the ratio of an insertion depth to length is approximately 0.007. In certain embodiments, the ratio of thickness to length t/L is preferably 0.0044≦t/L≦0.0143.

Thus, a blowing function may be improved or maximized in a fan of an indoor unit as embodied and broadly described herein when designed based on the noise level parameters shown in FIGS. 6 to 9. In particular, the blowing function may be improved and the noise level may be reduced when a fan 17 and its blade 171 have a structure that takes these parameters into consideration.

FIG. 10 is a graph of noise performance improvement of an indoor unit including such a fan. As shown in FIG. 10, noise generated by a fan that does not include the improved structure as described above is represented by the lighter, grey portion of the graph, while noise generated by a fan including the improved structure as described above is represented by the black portion of the graph. A mean, or average, noise difference between these two exemplary fans, i.e., the mean or average of the noise level difference between the “before” and “after” lines at measured corresponding points is approximately 2.2. Thus, noise may be reduced by about 2.2 dB when the structure of the fan is improved as described above. This allows blowing performance of the fan to be increased and system resistance and fan noise to be reduced, and may be applied regardless of the size of the indoor unit and/or the size of the fan.

An indoor unit for an air conditioning apparatus as embodied and broadly described herein may include a chassis including a stabilizer that generates a flow of air, and a fan insertion groove; a cross flow fan that is mounted on a front surface of the chassis corresponding to an upper end of the stabilizer, to inhale indoor air; a heat exchanger that is provided on a front side of the fan to perform a heat exchange with the indoor air, wherein 0.088≦T/L≦0.132 (T: thickness of fan, L: length of fan).

In an indoor unit for an air conditioning apparatus as embodied and broadly described herein, system resistance may be reduced even when a 3 row heat exchanger is applied in order to improve heat exchange efficiency of the indoor unit. Also, although resistance due to dust accumulated on a heat exchanger or a filter is increased due to extended use, the fan may be normally operated without generating abnormal noise. Also, although a 3 row heat exchanger is used, the noise level may be reduced.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, numerous variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

1. An indoor unit for an air conditioning apparatus, comprising: a chassis, including: a stabilizer; anda fan insertion groove formed at a first end of the stabilizer and a fan supporter provided at a second end of the stabilizer;a cross flow fan supported in the chassis by the fan insertion groove and the fan supporter, and extending across a portion of the stabilizer, wherein the fan draws indoor air into the indoor unit and the stabilizer guides the indoor air through the indoor unit; anda heat exchanger provided an inlet side of the cross flow fan so as to perform a heat exchange with the indoor air, wherein a ratio of a thickness T of a blade of the fan to a chord length L of the blade of the fan is greater than or equal to 0.088 and less than or equal to 0.132.

2. The indoor unit of claim 1, wherein a ratio of an inner diameter D1 to an outer diameter D2 of the fan is greater than or equal to 0.77 and less than or equal to 0.80.

3. The indoor unit of claim 1, wherein an outer circumferential angle β2 of the cross flow fan is greater than or equal to 30 degrees and less than or equal to 32 degrees.

4. The indoor unit of claim 1, wherein a ratio of an insertion depth t of the fan to the chord length L of the blade is greater than or equal to 0.0044 and less than or equal to 0.0143.

5. The indoor unit of claim 1, further comprising: a front frame coupled to the chassis so as to form an interior space of the indoor unit therebetween, wherein the fan and the heat exchanger are positioned in the interior space;an inlet grill and an inlet port formed in the front frame, each at positions corresponding to respective portions of the heat exchanger so as to guide indoor air therethrough and into the heat exchanger;a front panel movably coupled to the front frame so as to selectively open and close the inlet port; anda discharge grill coupled to the front frame and positioned so as to define an outlet port together with the chassis.

6. The indoor unit of claim 5, wherein the heat exchanger is positioned in the interior space between the inlet grill and the fan, and between the inlet port and the fan, such that rotation of the fan draws indoor air through the inlet grill and the inlet port and through the heat exchanger for heat exchange, and then draws heat exchanged air through the fan for discharge from the indoor unit through the outlet port.

7. The indoor unit of claim 5, further comprising: a louver rotatably positioned between an outlet of the fan and the outlet port, wherein the louver controls a lateral flow direction of heat exchanged air through the outlet port; anda vane rotatably positioned at the outlet port, wherein the vane selectively opens and closes the outlet port and controls a vertical flow direction of heat exchanged air through the outlet port.

8. The indoor unit of claim 1, wherein the fan includes a plurality of blades each having a predetermined curvature from a root end to a tip end thereof, and a mean camber line that bisects the thickness T of the blade and follows the predetermined curvature of the blade.

9. The indoor unit of claim 8, wherein an inner circumferential angle β1 is formed between a first line that connects a root end of the mean camber line and a center of the fan and a second line that extends tangentially through the root end of the blade, and an outer circumferential angle β2 is formed between a third line formed as an extension of the mean camber line from a tip end of the blade and a fourth line that extends tangentially through the tip end of the blade.

10. The indoor unit of claim 8, wherein the predetermined curvature of the blade includes a first predetermined curvature that defines a first surface of the blade, and a second predetermined curvature that defines a second surface of the blade opposite the first surface, wherein the first predetermined curvature is different from the second predetermined curvature such that the thickness T of the blade varies along the chord length.