U.S. patent application number 13/980584 was filed with the patent office on 2013-11-14 for heat exchanger and air conditioner.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. The applicant listed for this patent is Junichi Hamadate, Masanori Jindou, Takuya Kazusa, Yasutaka Ohtani, Yoshio Oritani, Shun Yoshioka. Invention is credited to Junichi Hamadate, Masanori Jindou, Takuya Kazusa, Yasutaka Ohtani, Yoshio Oritani, Shun Yoshioka.
Application Number | 20130299152 13/980584 |
Document ID | / |
Family ID | 46515551 |
Filed Date | 2013-11-14 |
United States Patent
Application |
20130299152 |
Kind Code |
A1 |
Ohtani; Yasutaka ; et
al. |
November 14, 2013 |
HEAT EXCHANGER AND AIR CONDITIONER
Abstract
A fin of a heat exchanger includes: a plurality of intermediate
plates arranged one above another and dividing a space between
adjacent ones of flat tubes into air passages; a plurality of tube
insertion portions each provided between vertically adjacent ones
of the intermediate plates, with an upwind side thereof being open
such that a corresponding one of the flat tubes is inserted
therein; a vertically extending downwind plate that is continuous
with downwind ends of the plurality of intermediate plates arranged
one above another; and a plurality of upwind plates extending
further toward an upwind side than the flat tubes from upwind side
ends of the intermediate plates. Each of the upwind plates is
provided with at least one upwind side heat-transfer portion which
projects toward the air passages.
Inventors: |
Ohtani; Yasutaka; (Osaka,
JP) ; Oritani; Yoshio; (Osaka, JP) ; Kazusa;
Takuya; (Osaka, JP) ; Jindou; Masanori;
(Osaka, JP) ; Hamadate; Junichi; (Osaka, JP)
; Yoshioka; Shun; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ohtani; Yasutaka
Oritani; Yoshio
Kazusa; Takuya
Jindou; Masanori
Hamadate; Junichi
Yoshioka; Shun |
Osaka
Osaka
Osaka
Osaka
Osaka
Osaka |
|
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
46515551 |
Appl. No.: |
13/980584 |
Filed: |
January 23, 2012 |
PCT Filed: |
January 23, 2012 |
PCT NO: |
PCT/JP2012/000392 |
371 Date: |
July 19, 2013 |
Current U.S.
Class: |
165/181 |
Current CPC
Class: |
F28F 1/325 20130101;
F28F 2215/12 20130101; F28D 1/05383 20130101; F28D 2021/0068
20130101; F28F 9/02 20130101; F25B 39/00 20130101; F28F 1/12
20130101; F28F 2215/04 20130101 |
Class at
Publication: |
165/181 |
International
Class: |
F28F 1/12 20060101
F28F001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 2011 |
JP |
2011-011269 |
Claims
1. A heat exchanger, comprising: a plurality of flat tubes arranged
one above another such that flat surfaces thereof face each other;
and a plurality of vertically extending, plate-like fins arranged
in an extension direction of the flat tubes, wherein each of the
fins includes a plurality of intermediate plates arranged one above
another and dividing a space between adjacent ones of the flat
tubes into air passages, a plurality of tube insertion portions
each provided between vertically adjacent ones of the intermediate
plates, with an upwind side thereof being open such that a
corresponding one of the flat tubes is inserted therein, a
vertically extending downwind plate that is continuous with
downwind ends of the plurality of intermediate plates arranged one
above another, and a plurality of upwind plates extending further
toward an upwind side than the flat tubes from upwind side ends of
the intermediate plates, and each of the upwind plates is provided
with at least one upwind side heat-transfer portion which projects
in a thickness direction of the fins.
2. The heat exchanger of claim 1, wherein the upwind side
heat-transfer portion includes a rib which extends in a protruding
direction of the upwind plates.
3. The heat exchanger of claim 2, wherein the upwind side
heat-transfer portion includes an intermediate heat-transfer
portion provided at a middle portion, in a vertical direction, of
each of the upwind plates, and the rib provided on at least one of
an upper side or a low side of the intermediate heat-transfer
portion.
4. The heat exchanger of claim 1, wherein the upwind side
heat-transfer portion includes a protrusion which extends in a
direction orthogonal to an air passage direction.
5. The heat exchanger of claim 1, wherein the upwind side
heat-transfer portion includes a raised portion formed by cutting
and bending part of the fin.
6. An air conditioner, comprising a refrigerant circuit including
the heat exchanger of claim 1, wherein the refrigerant circuit
performs a refrigeration cycle by circulating a refrigerant.
7. The heat exchanger of claim 2, wherein the upwind side
heat-transfer portion includes a protrusion which extends in a
direction orthogonal to an air passage direction.
8. The heat exchanger of claim 3, wherein the upwind side
heat-transfer portion includes a protrusion which extends in a
direction orthogonal to an air passage direction.
9. The heat exchanger of claim 2, wherein the upwind side
heat-transfer portion includes a raised portion formed by cutting
and bending part of the fin.
10. The heat exchanger of claim 3, wherein the upwind side
heat-transfer portion includes a raised portion formed by cutting
and bending part of the fin.
11. The heat exchanger of claim 4, wherein the upwind side
heat-transfer portion includes a raised portion formed by cutting
and bending part of the fin.
12. An air conditioner, comprising a refrigerant circuit including
the heat exchanger of claim 2, wherein the refrigerant circuit
performs a refrigeration cycle by circulating a refrigerant.
13. An air conditioner, comprising a refrigerant circuit including
the heat exchanger of claim 3, wherein the refrigerant circuit
performs a refrigeration cycle by circulating a refrigerant.
14. An air conditioner, comprising a refrigerant circuit including
the heat exchanger of claim 4, wherein the refrigerant circuit
performs a refrigeration cycle by circulating a refrigerant.
15. An air conditioner, comprising a refrigerant circuit including
the heat exchanger of claim 5, wherein the refrigerant circuit
performs a refrigeration cycle by circulating a refrigerant.
Description
TECHNICAL FIELD
[0001] The present invention relates to heat exchangers having a
flat tube and a fin and configured to exchange heat between a fluid
flowing in the flat tube and air, and air conditioners having the
heat exchangers.
BACKGROUND ART
[0002] Heat exchangers having a flat tube and a fin have been
known. Patent Document 1 and Patent Document 2 show heat exchangers
of this type. In the heat exchangers shown in these patent
documents, a plurality of flat tubes, each extending in a
horizontal direction, are arranged one above another with a
predetermined space between the flat tubes, and plate-like fins are
arranged in a direction along which the flat tubes extend, with a
predetermined space between the fins. For example, in the heat
exchanger shown in FIG. 2 of Patent Document 2, elongated cutouts
are formed in the fins, and the flat tube is inserted in each of
the cutouts. In this heat exchanger, air flowing in an air passage
between adjacent flat tubes is heat exchanged with a fluid flowing
in the flat tube.
CITATION LIST
Patent Document
[0003] Patent Document 1: Japanese Patent Publication No.
2003-262485 [0004] Patent Document 2: Japanese Patent Publication
No. 2010-054060
SUMMARY OF THE INVENTION
Technical Problem
[0005] In the heat exchanges shown in Patent Documents 1 and 2,
when the air flowing in the air passage is 0.degree. C. or lower,
moisture in the air freezes and frost may adhere to the surfaces of
the fins. If the amount of frost adhering to the surfaces of the
fins increases in the air passage, a heat-transfer rate of the fin
may decrease, or a flow pass resistance of the air passage may
increase.
[0006] The present invention is thus intended to prevent frost, in
a heat exchanger having a plurality of flat tubes and a plurality
of fins, from adhering to a surface of each fin in an air
passage.
Solution to the Problem
[0007] The first aspect of the present invention is directed to a
heat exchanger, including: a plurality of flat tubes (33) arranged
one above another such that flat surfaces thereof face each other;
and a plurality of vertically extending, plate-like fins (36)
arranged in an extension direction of the flat tubes (33), wherein
each of the fins (36) includes a plurality of intermediate plates
(70) arranged one above another and dividing a space between
adjacent ones of the flat tubes (33) into air passages (40), a
plurality of tube insertion portions (46) each provided between
vertically adjacent ones of the intermediate plates (70), with an
upwind side thereof being open such that a corresponding one of the
flat tubes (33) is inserted therein, a vertically extending
downwind plate (75) that is continuous with downwind ends of the
plurality of intermediate plates (70) arranged one above another,
and a plurality of upwind plates (77) extending further toward an
upwind side than the flat tubes (33) from upwind side ends of the
intermediate plates (70), and each of the upwind plates (77) is
provided with at least one upwind side heat-transfer portion (81,
91, 92, 95) which projects in a thickness direction of the fins
(36).
[0008] In the fin (36) of the first aspect of the present
invention, a plurality of upwind plates (77) project from the
upwind ends of the plurality of intermediate plates (70) to the
upwind side. When air passes through the heat exchanger serving as
an evaporator, the air is cooled first by the upwind plates (77).
When the air is cooled by the upwind plates (77) to a temperature
equal to or lower than a dew point, moisture in the air is
condensed. When the temperature of the air flowing on the lateral
sides of the upwind plates (77) is equal to or lower than 0.degree.
C., moisture in the air turns into frost on the surface of the
upwind plates (77). In the present invention, since moisture in the
air flowing on the lateral sides of the upwind plates (77) is
condensed, or turns into frost as described above, the air is
dehumidified.
[0009] The air dehumidified in this manner flows in the air
passages (40) along the intermediate plates (70). The intermediate
plates (70) are located relatively close to the flat tubes (33),
and thus, the air flowing in the air passages (40) is cooled
rapidly. However, this air has been dehumidified by the upwind
plates (77), and therefore, the accumulation of frost on the
surfaces of the intermediate plate (70) is reduced.
[0010] Here, the air flowing on the lateral sides of the upwind
plates (77) is not easily cooled, compared to the air flowing in
the air passages (40), because the upwind plates (77) are located
relatively far from the flat tubes (33). However, in the fin (36)
of the present invention, each of the upwind plates (77) is
provided with an upwind side heat-transfer portion (81, 91, 92,
95), and therefore, heat transfer between the air and the upwind
plates (77) is promoted. As a result, the air flowing on the
lateral sides of the upwind plates (77) can be easily cooled, and
the effect of dehumidifying the air is improved. Thus, in the
present invention, the accumulation of frost on the surfaces of the
intermediate plates (70) can be further advantageously reduced.
[0011] The second aspect of the present invention is that in the
first aspect of the present invention, the upwind side
heat-transfer portion includes a rib (91, 92) which extends in a
protruding direction of the upwind plates (77).
[0012] According to the second aspect of the present invention, the
upwind plate (77) is provided with the rib (91, 92). The rib (91,
92) comprises an upwind side heat-transfer portion. Thus, the air
flowing on the lateral sides of the upwind plates (77) can be
easily cooled, and the effect of dehumidifying the air is
improved.
[0013] Further, in the fin (36) of the present invention, the
upwind plate (77) projects from the intermediate plate (70). This
may lead to easy bending of the upwind plate (77) in a horizontal
direction with respect to the intermediate plate (70). However, the
rib (91, 92) of the upwind plate (77) is provided so as to extend
in the projecting direction of the upwind plate (77) to increase
the bending strength of the upwind plate (77) in the horizontal
direction. Thus, it is possible to prevent the upwind plate (77)
from being bent in the horizontal direction.
[0014] The third aspect of the present invention is that in the
second aspect of the present invention, the upwind side
heat-transfer portion includes an intermediate heat-transfer
portion (81, 95) provided at a middle portion, in a vertical
direction, of each of the upwind plates (77), and the rib (91, 92)
provided on at least one of an upper side or a low side of the
intermediate heat-transfer portion (81, 95).
[0015] According to the third aspect of the present invention, the
upwind plate (77) is provided with the intermediate heat-transfer
portion (81, 95). The intermediate heat-transfer portion (81, 95)
comprises an upwind side heat-transfer portion. Since the
intermediate heat-transfer portion (81, 95) is provided at a middle
portion, in the vertical direction, of the upwind plate (77), heat
transfer between the air and the intermediate heat-transfer portion
(81, 95) is promoted, and the effect of cooling the air is
improved. The intermediate heat-transfer portion (81, 95) provided
on the upwind plate (77) may easily lead the air to the upper side
or the lower side of the intermediate heat-transfer portion (81,
95). However, in the present invention, the rib (91, 92) is
provided on the upper side or the lower side of the intermediate
heat-transfer portion (81, 95), and therefore, heat transfer
between the air and the rib (91, 92) is promoted as well. As a
result, the effect of cooling the air flowing on the lateral sides
of the upwind plates (77) is further improved.
[0016] The fourth aspect of the present invention is that in any
one of the first to third aspects of the present invention, the
upwind side heat-transfer portion includes a protrusion (81) which
extends in a direction orthogonal to an air passage direction.
[0017] According to the fourth aspect of the present invention, the
upwind plate (77) is provided with the protrusion (81). The
protrusion (81) comprises an upwind side heat-transfer portion.
Since the protrusion (81) extends in a direction which intersects
with the air passage direction, heat transfer between the air and
the protrusion (81) is promoted, and the effect of cooling the air
is improved.
[0018] The fifth aspect of the present invention is that in any one
of the first to fourth aspects of the present invention, the upwind
side heat-transfer portion includes a raised portion (95) formed by
cutting and bending part of the fin (36).
[0019] According to the fifth aspect of the present invention, the
upwind plate (77) is provided with the raised portion (95) as an
upwind side heat-transfer portion. As a result, heat transfer
between the air and the raised portion (95) is promoted, and the
effect of cooling the air is improved.
[0020] The sixth aspect of the present invention is directed to an
air conditioner, and having a refrigerant circuit (20) including
the heat exchanger (30) of any one of the first to fifth aspects of
the present invention, wherein the refrigerant circuit (20)
performs a refrigeration cycle by circulating a refrigerant.
[0021] According to the sixth aspect of the present invention, the
heat exchanger (30) of the first to fifth aspects of the present
invention is applied to the air conditioner. Thus, in the heat
exchanger (30) serving as an evaporator, the accumulation of frost
on the surfaces of the intermediate plates (70) which partition the
air passages (40) is reduced.
Advantages of the Invention
[0022] In the present invention, the upwind plates (77) are
provided so as to extend from the intermediate plates (70) of the
fin (36) to the upwind side, and each of the upwind plates (77) is
provided with the upwind side heat-transfer portion (81, 91, 92,
95). Thus, the air before flowing into the air passages (40) can be
dehumidified by the upwind plates (77). This can reduce the
accumulation of frost on the surfaces of the intermediate plates
(70), and thus, it is possible to prevent a reduction in
heat-transfer rate of the fin (36), and an increase in flow pass
resistance of the air passages (40).
[0023] According to the second aspect of the present invention, the
rib (91, 92) can improve the effect of cooling the air, and prevent
bending of the upwind plates (77). Since leaning of the upwind
plates (77) is prevented as mentioned, the air can flow evenly into
the air passages (40). As a result, reliability of the heat
exchanger can be ensured.
[0024] According to the third to fifth aspects of the present
invention, heat transfer between the air and the upwind plates (77)
can be promoted, and the effect of cooling the air by the upwind
plates (77) can be further improved. Further, according to the
fifth aspect of the present invention, the tip of the raised
portion (95) is in contact with the adjacent upwind plate (77),
thereby preventing the upwind plate (77) from leaning
horizontally.
[0025] According to the sixth aspect of the present invention, in
the heat exchanger (30) serving as an evaporator, the amount of
frost adhering to the intermediate plates (70) facing the air
passages (40) can be reduced. Thus, it is possible to reduce the
time of the defrosting operation of the heat exchanger (30) for
melting the frost, and accordingly extend the time of the heating
operation by the reduced period of time. As a result, it is
possible to promote energy conservation of the air conditioner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a refrigerant circuit diagram showing a schematic
configuration of an air conditioner having a heat exchanger of an
embodiment.
[0027] FIG. 2 is an oblique view schematically showing the heat
exchanger of the embodiment.
[0028] FIG. 3 is a partial cross-sectional view of the front side
of the heat exchanger of the embodiment.
[0029] FIG. 4 is a cross-sectional view of part of the heat
exchanger taken along the line A-A of FIG. 3.
[0030] FIG. 5 shows a main part of a fin of the heat exchanger of
the embodiment. FIG. 5(A) is a front side of the fin. FIG. 5(B) is
a cross-sectional view taken along the line B-B of FIG. 5(A).
[0031] FIG. 6 shows cross-sectional views of the fins of the heat
exchanger of the embodiment. FIG. 6(A) is a cross-section taken
along the line C-C of FIG. 5. FIG. 6(B) is a cross-section taken
along the line D-D of FIG. 5.
DESCRIPTION OF EMBODIMENTS
[0032] An embodiment of the present invention will be described in
detail below, based on the drawings. The following embodiment is
merely a preferred example in nature, and is not intended to limit
the scope, applications, and use of the invention.
[0033] A heat exchanger (30) of the embodiment comprises an outdoor
heat exchanger (23) of an air conditioner (10) described later.
[0034] --Air Conditioner--
[0035] The air conditioner (10) having the heat exchanger (30) of
the present embodiment will be described with reference to FIG.
1.
[0036] <Configuration of Air Conditioner>
[0037] The air conditioner (10) has an outdoor unit (11) and an
indoor unit (12). The outdoor unit (11) and the indoor unit (12)
are connected to each other via a liquid communication pipe (13)
and a gas communication pipe (14). In the air conditioner (10), a
refrigerant circuit (20) is formed by the outdoor unit (11), the
indoor unit (12), the liquid communication pipe (13), and the gas
communication pipe (14).
[0038] The refrigerant circuit (20) includes a compressor (21), a
four-way valve (22), an outdoor heat exchanger (23), an expansion
valve (24), and an indoor heat exchanger (25). The compressor (21),
the four-way valve (22), the outdoor heat exchanger (23), and the
expansion valve (24) are accommodated in the outdoor unit (11). The
outdoor unit (11) is provided with an outdoor fan (15) configured
to supply outdoor air to the outdoor heat exchanger (23). The
indoor heat exchanger (25) is accommodated in the indoor unit (12).
The indoor unit (12) is provided with an indoor fan (16) configured
to supply indoor air to the indoor heat exchanger (25).
[0039] The refrigerant circuit (20) is a closed circuit filled with
a refrigerant. In the refrigerant circuit (20), a discharge side of
the compressor (21) is connected to a first port of the four-way
valve (22), and a suction side of the compressor (21) is connected
to a second port of the four-way valve (22). In the refrigerant
circuit (20), the outdoor heat exchanger (23), the expansion valve
(24), and the indoor heat exchanger (25) are provided sequentially
from a third port to a fourth port of the four-way valve (22).
[0040] The compressor (21) is a scroll type or rotary type hermetic
compressor. The four-way valve (22) switches between a first state
(the state shown in broken line in FIG. 1) in which the first port
communicates with the third port, and the second port communicates
with the fourth port, and a second state (the state shown in solid
line in FIG. 1) in which the first port communicates with the
fourth port, and the second port communicates with the third port.
The expansion valve (24) is a so-called electronic expansion valve
(24).
[0041] In the outdoor heat exchanger (23), the outdoor air is heat
exchanged with the refrigerant. The outdoor heat exchanger (23) is
comprised of the heat exchanger (30) of the present embodiment. In
the indoor heat exchanger (25), the indoor air is heat exchanged
with the refrigerant. The indoor heat exchanger (25) is comprised
of a so-called cross-fin type fin-and-tube heat exchanger having a
circular heat-transfer tube.
[0042] <Cooling Operation>
[0043] The air conditioner (10) performs a cooling operation. The
four-way valve (22) is set to the first state during the cooling
operation. The outdoor fan (15) and the indoor fan (16) are driven
during the cooling operation.
[0044] The refrigerant circuit (20) performs a refrigeration cycle.
Specifically, the refrigerant discharged from the compressor (21)
passes through the four-way valve (22), flows into the outdoor heat
exchanger (23), and dissipates heat to the outdoor air and
condenses. The refrigerant flowing out of the outdoor heat
exchanger (23) expands when it passes through the expansion valve
(24), flows into the indoor heat exchanger (25), and takes heat
from the indoor air and evaporates. The refrigerant flowing out of
the indoor heat exchanger (25) passes through the four-way valve
(22) and is then sucked into the compressor (21) and compressed.
The indoor unit (12) supplies air which has been cooled in the
indoor heat exchanger (25) to an indoor space.
[0045] <Heating Operation>
[0046] The air conditioner (10) performs a heating operation. The
four-way valve (22) is set to the second state during the heating
operation. The outdoor fan (15) and the indoor fan (16) are driven
during the heating operation.
[0047] The refrigerant circuit (20) performs a refrigeration cycle.
Specifically, the refrigerant discharged from the compressor (21)
passes the four-way valve (22), flows into the indoor heat
exchanger (25), and dissipates heat to the indoor air and
condenses. The refrigerant flowing out of the indoor heat exchanger
(25) expands when it passes through the expansion valve (24), flows
into the outdoor heat exchanger (23), and takes heat from the
outdoor air and evaporates. The refrigerant flowing out of the
outdoor heat exchanger (23) passes through the four-way valve (22)
and is then sucked into the compressor (21) and compressed. The
indoor unit (12) supplies air which has been heated in the indoor
heat exchanger (25) to an indoor space.
[0048] <Defrosting Operation>
[0049] As described above, the outdoor heat exchanger (23)
functions as an evaporator in the heating operation. In the
operation under low outdoor air temperature conditions, the
evaporation temperature of the refrigerant in the outdoor heat
exchanger (23) may sometimes be below 0.degree. C. In this case,
the moisture in the outdoor air turns into frost and adheres to the
outdoor heat exchanger (23). To avoid this, the air conditioner
(10) performs a defrosting operation every time a duration of the
heating operation reaches a predetermined value (e.g., several tens
of minutes), for example.
[0050] To start the defrosting operation, the four-way valve (22)
is switched from the second state to the first state, and the
outdoor fan (15) and the indoor fan (16) are stopped. In the
refrigerant circuit (20) during the defrosting operation, a high
temperature refrigerant discharged from the compressor (21) is
supplied to the outdoor heat exchanger (23). The frost adhering to
the surface of the outdoor heat exchanger (23) is heated and melted
by the refrigerant. The refrigerant which dissipates heat in the
outdoor heat exchanger (23) sequentially passes through the
expansion valve (24) and the indoor heat exchanger (25), and is
then sucked into the compressor (21) and compressed. When the
defrosting operation is finished, the heating operation starts
again. That is, the four-way valve (22) is switched from the first
state to the second state, and the outdoor fan (15) and the indoor
fan (16) are driven again.
[0051] --Heat Exchanger of First Embodiment--
[0052] The heat exchanger (30) of the present embodiment which
comprises the outdoor heat exchanger (23) of the air conditioner
(10) will be described with reference to FIGS. 2 to 6.
[0053] <General Configuration of Heat Exchanger>
[0054] As shown in FIG. 2 and FIG. 3, the heat exchanger (30) of
the present embodiment includes one first header collecting pipe
(31), one second header collecting pipe (32), a plurality of flat
tubes (33), and a plurality of fins (35). The first header
collecting pipe (31), the second header collecting pipe (32), the
flat tubes (33), and the fins (35) are all aluminum alloy members,
and are attached to one another with solder.
[0055] Both of the first header collecting pipe (31) and the second
header collecting pipe (32) are in an elongated hollow cylindrical
shape, with both ends closed. In FIG. 3, the first header
collecting pipe (31) is provided upright at the left end of the
heat exchanger (30), and the second header collecting pipe (32) is
provided upright at the right end of the heat exchanger (30). In
other words, the first header collecting pipe (31) and the second
header collecting pipe (32) are provided such that their axial
directions are vertical.
[0056] As is also shown in FIG. 4, the flat tube (33) is a
heat-transfer tube having a flat oblong cross section or a
rectangular cross section with rounded corners. In the heat
exchanger (30), the plurality of flat tubes (33) extend in a
horizontal direction, and are arranged such that the flat surfaces
thereof face each other. Further, the plurality of flat tubes (33)
are arranged one above another with a predetermined space between
the flat tubes (33). One end of each of the flat tubes (33) is
inserted in the first header collecting pipe (31), and the other
end of the flat tube (33) is inserted in the second header
collecting pipe (32).
[0057] Each fin (36) is in a plate-like shape, and the fins (36)
are arranged in an extension direction of the flat tube (33) with a
predetermined space between the fins (36). In other words, the fins
(36) are arranged to be substantially orthogonal to the extension
direction of the flat tube (33). As will be described in detail
later, an area of each fin (36) which is located between vertically
adjacent flat tubes (33) comprises an intermediate plate (70).
[0058] As shown in FIG. 3, in the heat exchanger (30), a space
between vertically adjacent flat tubes (33) is divided into a
plurality of air passages (40) by the intermediate plates (70) of
the fins (36). In the heat exchanger (30), the refrigerant flowing
in the fluid passages (34) of the flat tube (33) exchanges heat
with the air flowing in the air passages (40).
[0059] <Configuration of Fin>
[0060] As shown in FIG. 4 and FIG. 5, each of the fins (36) is a
vertically elongate plate-like fin formed by pressing a metal
plate. The thickness of each fin (36) is approximately 0.1 mm.
[0061] The fin (36) is provided with a plurality of elongate
cutouts (45) each extending in a width direction (i.e., in an air
passage direction) of the fin (36) from a leading edge (38) of the
fin (36). The plurality of cutouts (45) are formed in the fin (36)
at predetermined intervals in a longitudinal direction (i.e., a
vertical direction) of the fin (36). Of the cutout (45), a portion
between the intermediate plates (70) of the fins (36) comprises a
tube insertion portion (46). The flat tube (33) is inserted in the
tube insertion portion (46) from the open upwind side, and is held.
The width of the tube insertion portion (46) in the vertical
direction is substantially equal to the width of the thickness of
the flat tube (33), and the length of the tube insertion portion
(46) is substantially equal to the width of the flat tube (33).
[0062] The flat tube (33) is inserted in the tube insertion portion
(46) of the fin (36) from the leading edge (38) of the fin (36).
The flat tube (33) is attached to the periphery of the tube
insertion portion (46) with solder. That is, the flat tube (33) is
fitted to the periphery of the tube insertion portion (46) which is
part of the cutout (45).
[0063] The fin (36) includes a plurality of intermediate plates
(70) in areas between vertically adjacent flat tubes (33), a
downwind plate (75) provided on the downwind side of the
intermediate plates (70), and an upwind plate (77) provided on the
upwind side of each of the plurality of intermediate plates (70).
The intermediate plates (70) divide the space between vertically
adjacent flat tubes (33) into the air passages (40). That is, the
intermediate plates (70) face the air passages (40). The downwind
plate (75) is continuous with the downwind ends of all the
intermediate plates (70) arranged one above another. Each of the
upwind plate (77) projects from a middle portion in the vertical
direction of the upwind end of each intermediate plate (70) toward
the upwind side. The height of each upwind plate (77) is smaller
than the height of each intermediate plate (70), and the width of
the upwind plate (77) is narrower than the width of the
intermediate plate (70).
[0064] The fin (36) is provided with louvers (50a, 50b) and
protrusions (81-83). In the fin (36), the protrusions (81-83) are
located upwind of the louvers (50a, 50b). The numbers of the
protrusions (81-83) and the louvers (50a, 50b) described below are
merely examples.
[0065] Specifically, the fin (36) is provided with three
protrusions (81-83) in an upwind side area. The three protrusions
(81-83) are arranged side by side in the air passage direction
(i.e., the direction from the leading edge (38) to the trailing
edge (39) of the fin (36)). That is, the fin (36) is provided with
a first protrusion (81), a second protrusion (82), and a third
protrusion (83) sequentially from the upwind side to the downwind
side. In the fin (36), the first protrusion (81) lies across the
upwind plate (77) and the intermediate plate (70), and the second
protrusion (82) and the third protrusion (83) are provided on the
intermediate plate (70).
[0066] Each of the protrusions (81-83) has an inverted V shape
formed by making the fin (36) protrude toward the air passage (40).
The three protrusions (81-83) protrude to the same direction. In
the fin (36) of the present embodiment, the protrusions (81-83)
protrude to the right when viewed from the leading edge (38) of the
fin (36). Ridges (81a, 82a, 83a) of the protrusions (81-83) (i.e.,
the line on the tip of each protrusion in the inverted V shape) are
substantially in parallel with the leading edge (38) of the fin
(36). That is, the ridges (81a, 82a, 83a) of the protrusions
(81-83) intersect with the airflow direction in the air passage
(40).
[0067] As shown in FIG. 5(B), the height H1 of the first protrusion
(81) in the protrusion direction, the height H2 of the second
protrusion (82) in the protrusion direction, and the height H3 of
the third protrusion (83) in the protrusion direction are equal
(H1=H2=H3). As shown in FIG. 5(A), the width W1 of the first
protrusion (81) in the air passage direction is smaller than the
width W2 of the second protrusion (82) in the air passage
direction, and the width W3 of the third protrusion (83) is smaller
than the width W1 of the first protrusion (81) in the air passage
direction (W1<W2<W3).
[0068] The intermediate plate (70) of the fin (36) is provided with
a group of louvers (50a, 50b) at the downwind side of the
protrusions (81-83). The louvers (50a, 50b) are obtained by giving
a plurality of slit-like cuts in the intermediate plate (70) and
plastically deforming a portion between adjacent cuts as if
twisting the portion. The longitudinal direction of each louver
(50a, 50b) is substantially parallel to the leading edge (38) of
the fin (36) (i.e., the vertical direction). That is, the
longitudinal direction of each louver (50a, 50b) intersects with
the air passage direction. The lengths of the louvers (50a, 50b)
are equal to each other.
[0069] As shown in FIG. 5(B), the louvers (50a, 50b) are tilted
with respect to their peripheral flat portions. Specifically,
bent-out ends (53a, 53b) on the upwind side of the louvers (50a,
50b) protrude to the left when viewed from the leading edge (38) of
the fin (36). On the other hand, bent-out ends (53a, 53b) of the
louvers (50a, 50b) on the downwind side protrude to the right when
viewed from the leading edge (38) of the fin (36).
[0070] As shown in FIGS. 6(A) and 6(B), each of the bent-out ends
(53a, 53b) of the louvers (50a, 50b) includes a main edge (54a,
54b), an upper edge (55a, 55b), a lower edge (56a, 56b). The main
edge (54a, 54b) extends substantially in parallel with the leading
edge (38) of the fin (36). The upper edge (55a, 55b) extends from
the upper end of the main edge (54a, 54b) to the upper end of the
louver (50a, 50b), and is tilted with respect to the main edge
(54a, 54b). The lower edge (56a, 56b) extends from the lower end of
the main edge (54a, 54b) to the lower end of the louver (50a, 50b),
and is tilted relative to the main edge (54a, 54b).
[0071] As shown in FIG. 5(A) and FIG. 6(A), in each of the
plurality of louvers (50a) located on the upwind side, a tilt angle
.theta.2 of the lower edge (56a) with respect to the main edge
(54a) is smaller than a tilt angle .theta.1 of the upper edge (55a)
with respect to the main edge (54a) (i.e., .theta.2<.theta.1).
Thus, in each louver (50a), the lower edge (56a) is longer than the
upper edge (55a). The upwind side louver (50a) is an asymmetric
louver in which the shape of the bent-out end (53a) is asymmetric
in the vertical direction.
[0072] On the other hand, as shown in FIG. 5(A) and FIG. 6(B), in
each of the plurality of louvers (50b) located on the downwind
side, a tilt angle .theta.4 of the lower edge (56b) with respect to
the main edge (54b) is equal to a tilt angle .theta.3 of the upper
edge (55b) with respect to the main edge (54b) (i.e.,
.theta.4=.theta.3). The louver (50b) is a symmetric louver in which
the shape of the bent-out end (53b) is symmetric in the vertical
direction. The tilt angle .theta.3 of the upper edge (55b) of the
downwind side louver (50b) is equal to the tilt angle .theta.1 of
the upper edge (55a) of the upwind side louver (50a) (i.e.,
.theta.3=.theta.1).
[0073] As shown in FIG. 5(A), the length L1 from the upper ends of
the second protrusion (82) and the third protrusion (83) to the
upper end of the intermediate plate (70), the length L2 from the
lower ends of the second protrusion (82) and the third protrusion
(83) to the lower end of the intermediate plate (70), the length L3
from the upper ends of the louvers (50a, 50b) to the upper end of
the intermediate plate (70), and the length L4 from the lower ends
of the louvers (50a, 50b) to the lower end of the intermediate
plate (70) are the same.
[0074] In each fin (36), one auxiliary protrusion (85) lies across
the intermediate plate (70) and the downwind plate (75).
[0075] The auxiliary protrusion (85) has an inverted V shape formed
by making the fin (36) protrude. In the fin (36) of the present
embodiment, each auxiliary protrusion (85) protrudes to the right
when viewed from the leading edge (38) of the fin (36). The ridge
(85a) of the auxiliary protrusion (85) is substantially in parallel
with the leading edge (38) of the fin (36). That is, the ridge
(85a) of the auxiliary protrusion (85) intersects with the airflow
direction in the air passage (40). In addition, the lower end of
the auxiliary protrusion (85) is tilted downward toward the
downwind side.
[0076] As shown in FIG. 5(B), the height H5 of the auxiliary
protrusion (85) in the protrusion direction is smaller than the
heights H1, H2, H3 of the first to third protrusions (81, 82, 83)
(H5<H1=H2=H3). As shown in FIG. 5(A), the width W5 of the
auxiliary protrusion (85) in the air passage direction is smaller
than the width W3 of the third protrusion (83) in the air passage
direction (W5<W3).
[0077] The downwind plate (75) of the fin (36) is provided with a
vertically extending water-conducting rib (49), a plurality of
downwind tabs (48) arranged in the vertical direction, and a
plurality of downwind protrusions (84) each provided between
vertically adjacent downwind tabs (48).
[0078] The water-conducting rib (49) is an elongated recessed
groove extending vertically along the trailing edge (39) of the fin
(36). The water-conducting rib (49) extends from the upper end to
the lower end of the downwind plate (75) of the fin (36).
[0079] Each of the downwind tabs (48) is a small rectangular piece
formed by cutting and bending the fin (36). The downwind tabs (48)
keep a space between the fins (36), with the tips thereof being in
contact with their adjacent fin (36).
[0080] Each downwind protrusion (84) has an inverted V shape formed
by making the downwind plate (75) protrude. In the fin (36) of the
present embodiment, each downwind protrusion (84) protrudes to the
right when viewed from the leading edge (38) of the fin (36).
Ridges (84a) of the downwind protrusions (84) are substantially in
parallel with the leading edge (38) of the fin (36). That is, the
ridges (84a) of the downwind protrusions (84) intersect with the
airflow direction in the air passage (40).
[0081] As shown in FIG. 5(B), the height H4 of the downwind
protrusion (84) in the protrusion direction is equal to the heights
H1, H2, H3 of the first to third protrusions (81, 82, 83)
(H4=H1=H2=H3). As shown in FIG. 5(A), the width W4 of the downwind
protrusion (84) in the air passage direction is equal to the width
W2 of the second protrusion (82) in the air passage direction
(W4=W2).
[0082] The fin (36) is provided with two horizontal ribs (91, 92),
and the above-described first protrusion (81) which lie across the
upwind plate (77) and the intermediate plate (70).
[0083] The first protrusion (81) comprises an intermediate
heat-transfer portion provided at a middle portion, in the vertical
direction, of the upwind plate (77). The first protrusion (81)
comprises an upwind side heat-transfer portion which promotes heat
transfer between the fin (36) and air on the upwind side of the
intermediate plate (70).
[0084] In each fin (36), the upper horizontal rib (91) is provided
at an area on the upper side of the first protrusion (81) and the
upwind tab (95), and the lower horizontal rib (92) is provided at
an area on the lower side of the first protrusion (81) and the
upwind tab (95). The horizontal ribs (91, 92) are comprised of
raised lines which protrude toward the air passage (40). The
direction to which the horizontal ribs (91, 92) protrude is the
same as the protrusion direction of the protrusions (81, 82, 83,
84). The upper horizontal rib (91) extends horizontally from the
leading edge (38) of the fin (36) to an upper portion of the second
protrusion (82). The lower horizontal rib (92) extends horizontally
from the leading edge (38) of the fin (36) to a lower portion of
the second protrusion (82). That is, in the fin (36), the two
horizontal ribs (91, 92) extend linearly in the protruding
direction of the upwind plates (77) (i.e., in the air passage
direction). The horizontal ribs (91, 92) comprise reinforcing ribs
which prevent the upwind plate (77) from being bent toward the air
passage (40) with respect to the intermediate plate (70) of the fin
(36). The horizontal ribs (91, 92) also comprise upwind side
heat-transfer portions which promote heat transfer between the fin
(36) and air on the upwind side of the intermediate plate (70).
[0085] The upwind tab (95) as a raised portion is provided on the
front side of each of the upwind plates (77). The upwind tab (95)
comprises an intermediate heat-transfer portion provided at a
middle portion, in the vertical direction, of the upwind plate
(77). The upwind tab (95) is a small rectangular piece formed by
cutting and bending the fin (36) so as to protrude in a thickness
direction of the fin (36). The front surface of the upwind tab (95)
is tilted obliquely downward with respect to the air passage
direction (i.e., the horizontal direction). Thus, an airflow
resistance of the heat exchanger (30) can be reduced, compared to
the case in which the front surface of the upwind tab (95) is
vertical. The upwind tab (95) keeps a space between the fins (36),
with the tips thereof being in contact with the adjacent fin (36).
The upwind tab (95) also comprises an upwind side heat-transfer
portion which promotes heat transfer between the fin (36) and air
on the upwind side of the intermediate plate (70).
[0086] --Reduction of Frost Adhering on Surfaces of Fins--
[0087] As described above, the outdoor heat exchanger (23) of the
present embodiment functions as an evaporator in the heating
operation. In the heat exchanger (30) in the heating operation, the
evaporation temperature of the refrigerant may sometimes be below
0.degree. C., and frost may adhere to the surface of the fin (36).
In the heat exchanger (30) of the present embodiment, the air
before flowing into the air passage (40) is cooled/dehumidified by
the upwind plates (77), thereby reducing the accumulation of frost
on the inner side of the air passage (40).
[0088] Specifically, the air which has been transferred by the
outdoor fan (15) and flowed into the heat exchanger (30) flows to
the downwind side along each of the upwind plates (77). The air
flowing on lateral sides of the upwind plates (77) contacts the
upwind tab (95) and the first protrusion (81), and is cooled. The
air which has flowed around the upwind tab (95) and the first
protrusion (81) and moved to the upper side or the lower side of
the upwind tab (95) and the first protrusion (81) contacts the
horizontal ribs (91, 92), and is cooled. Thus, in the fin (36), the
upwind tab (95), the first protrusion (81), and the horizontal ribs
(91, 92) comprise heat-transfer promotion portions which promote
heat transfer between air and the upwind plates (77).
[0089] When the air is cooled by the upwind plates (77) to a
temperature equal to or lower than a dew point, moisture in the air
is condensed. When the air is cooled by the upwind plates (77) to a
temperature equal to or lower than 0.degree. C., moisture in the
air is frozen, and frost adheres to the surfaces of the upwind
plates (77). Thus, on the lateral sides of the upwind plates (77),
moisture in the air is condensed or turns into frost, thereby
dehumidifying the air.
[0090] The air dehumidified on the lateral sides of the upwind
plates (77) flows to the air passages (40) partitioned by the
intermediate plates (70). The intermediate plates (70) are
relatively close to the flat tubes (33), and thus, the air flowing
in the air passages (40) is cooled rapidly. However, this air has
been dehumidified before flowing into the air passages (40), and
therefore, the accumulation of frost on the surfaces of the
intermediate plates (70) is reduced.
Advantages of Embodiment
[0091] In the above embodiment, the upwind plates (77) extend from
the intermediate plates (70) of the fin (36) toward the upwind
side. Thus, the air before flowing into the air passages (40) can
be cooled and dehumidified. Moreover, since each of the upwind
plates (77) is provided with the upwind tab (95), the first
protrusion (81), and the horizontal ribs (91, 92), it is possible
to promote heat transfer between the air and the upwind plates
(77), and improve the effect of dehumidifying the air. By
dehumidifying the air before flowing into the air passages (40) in
the manner as described above, the accumulation of frost on the
surfaces of the intermediate plates (70) is reduced. As a result,
it is possible to prevent a reduction in heat-transfer rate of the
fin (36) and an increase in flow pass resistance of the air
passages (40) due to accumulation of frost.
[0092] Since the accumulation of frost on the intermediate plates
(70) is reduced as described above, it is possible to reduce the
time of the above-mentioned defrosting operation. As a result, it
is possible to extend the time of the heating operation, and
promote energy conservation.
[0093] Further, the two horizontal ribs (91, 92) provided on each
of the upwind plates (77) prevent the upwind plates (77) from being
bent in the horizontal direction with respect to the intermediate
plate (70). Such bending of the upwind plates (77) can be further
prevented by the upwind tab (95) whose tip is brought into contact
with the adjacent fin (36).
Other Embodiments
[0094] In the upwind plates (77) of the above embodiment, any of
the upwind tab (95), the first protrusion (81), and the two
horizontal ribs (91, 92) may be omitted. Further, each of the
upwind plates (77) may be provided with the louvers (50a, 50b) of
the above embodiment, and the louvers (50a, 50b) may be used as
upwind side heat-transfer portions (raised portions).
INDUSTRIAL APPLICABILITY
[0095] As described above, the present invention is useful for a
heat exchanger having a flat tube and a fin, and configured to
exchange heat between a fluid flowing in the flat tube and air.
DESCRIPTION OF REFERENCE CHARACTERS
[0096] 10 air conditioner [0097] 20 refrigerant circuit [0098] 30
heat exchanger [0099] 33 flat tube [0100] 36 fin [0101] 38 leading
edge [0102] 40 air passage [0103] 46 tube insertion portion [0104]
70 intermediate plate [0105] 75 downwind plate [0106] 77 upwind
plate [0107] 81 first protrusion (upwind side heat-transfer
portion, intermediate heat-transfer portion) [0108] 91 upper
horizontal rib (upwind side heat-transfer portion) [0109] 92 lower
horizontal rib (upwind side heat-transfer portion) [0110] 95 upwind
tab (upwind side heat-transfer portion, raised portion,
intermediate heat-transfer portion)
* * * * *