U.S. patent application number 16/977284 was filed with the patent office on 2021-01-07 for heat exchanger.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. The applicant listed for this patent is DAIKIN INDUSTRIES, LTD.. Invention is credited to Tooru Andou, Hideyuki Kusaka, Hiroyuki Nakano, Shun Yoshioka.
Application Number | 20210003350 16/977284 |
Document ID | / |
Family ID | |
Filed Date | 2021-01-07 |
![](/patent/app/20210003350/US20210003350A1-20210107-D00000.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00001.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00002.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00003.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00004.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00005.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00006.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00007.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00008.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00009.png)
![](/patent/app/20210003350/US20210003350A1-20210107-D00010.png)
View All Diagrams
United States Patent
Application |
20210003350 |
Kind Code |
A1 |
Nakano; Hiroyuki ; et
al. |
January 7, 2021 |
HEAT EXCHANGER
Abstract
A heat exchanger includes: heat transfer units that each
comprise heat transfer channel portions and auxiliary heat transfer
portions. The heat transfer channel portions and the auxiliary heat
transfer portions extend in a first direction and are disposed in a
second direction that intersects with or is perpendicular to the
first direction. The heat transfer units are disposed in a third
direction that is different from both of the first direction and
the second direction. The heat transfer units each has an
airflow-upstream region and an airflow-downstream region in the
second direction. When the heat exchanger is used as an evaporator,
the heat exchanger causes a refrigerant to flow into a heat
transfer channel portion disposed in the airflow-upstream region,
and then causes the refrigerant to flow out to a heat transfer
channel portion disposed in the airflow-downstream region.
Inventors: |
Nakano; Hiroyuki;
(Osaka-shi, Osaka, JP) ; Andou; Tooru; (Osaka-shi,
Osaka, JP) ; Kusaka; Hideyuki; (Osaka-shi, Osaka,
JP) ; Yoshioka; Shun; (Osaka-shi, Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAIKIN INDUSTRIES, LTD. |
Osaka |
|
JP |
|
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka
JP
|
Appl. No.: |
16/977284 |
Filed: |
February 22, 2019 |
PCT Filed: |
February 22, 2019 |
PCT NO: |
PCT/JP2019/006840 |
371 Date: |
September 1, 2020 |
Current U.S.
Class: |
1/1 |
International
Class: |
F28F 1/26 20060101
F28F001/26 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 1, 2018 |
JP |
2018-036981 |
Claims
1-9. (canceled)
10. A heat exchanger comprising: heat transfer units that each
comprise heat transfer channel portions and auxiliary heat transfer
portions, wherein the heat transfer channel portions and the
auxiliary heat transfer portions extend in a first direction and
are disposed in a second direction that intersects with or is
perpendicular to the first direction, the heat transfer units are
disposed in a third direction that is different from both of the
first direction and the second direction, the heat transfer units
each has an airflow-upstream region and an airflow-downstream
region in the second direction, and when the heat exchanger is used
as an evaporator, the heat exchanger causes a refrigerant to flow
into a heat transfer channel portion disposed in the
airflow-upstream region, and then causes the refrigerant to flow
out to a heat transfer channel portion disposed in the
airflow-downstream region.
11. The heat exchanger according to claim 1, wherein a number of
heat transfer channel portions disposed in the airflow-downstream
region is larger than a number of heat transfer channel portions
disposed in the airflow-upstream region.
12. The heat exchanger according to claim 10, further comprising: a
decompressing mechanism that decompresses the refrigerant, wherein
the heat exchanger causes the refrigerant to flow from the heat
transfer channel portion disposed in the airflow-upstream region
into the heat transfer channel portion disposed in the
airflow-downstream region via the decompressing mechanism.
13. The heat exchanger according to claim 10, further comprising:
an upper header connected to the heat transfer units from above in
the first direction; and a lower header connected to the heat
transfer units from below in the first direction, wherein the upper
header and the lower header form a part of a channel of the
refrigerant.
14. The heat exchanger according to claim 13, wherein the
airflow-upstream region and the airflow-downstream region are
separated by a partition disposed inside of at least one of the
upper header or the lower header.
15. The heat exchanger according to claim 10, wherein each of the
heat transfer units comprises eight or more heat transfer channel
portions, and at least two or more of the heat transfer channel
portions are disposed in the airflow-upstream region.
16. The heat exchanger according to claim 10, wherein, when viewed
from the first direction, a heat insulator is applied to an end
portion of each of the heat transfer units in the second
direction.
17. The heat exchanger according to claim 7, wherein in each of the
heat transfer units, one of the auxiliary heat transfer portions is
at an end of the respective heat transfer units in the second
direction when viewed from the first direction, and the one of the
auxiliary heat transfer portion in each of the heat transfer units
has a closed shape.
18. An air conditioner comprising the heat exchanger according to
claim 10.
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat exchanger.
BACKGROUND
[0002] Conventional heat exchangers used in an air conditioner or
the like include a small-diameter heat transfer tube unit that is
formed by stacking heat transfer fin plates (see, for example,
Patent Literature 1 (Japanese Unexamined Patent Application
Publication No. 2006-90636) and the like).
[0003] When a heat exchanger is used as an evaporator in a low
temperature environment, frosting may concentratedly occur in a
part of the heat exchanger due to internal heat flux distribution.
Then, blockage of an air passage may occur in the part where
frosting has concentratedly occurred, and the performance of the
heat exchanger may decrease.
SUMMARY
[0004] A heat exchanger according to a first aspect includes a
plurality of heat transfer units in each of which a plurality of
heat transfer channel portions and a plurality of auxiliary heat
transfer portions, each of which extends in a first direction, are
formed so as to be arranged in a second direction that intersects
with or is perpendicular to the first direction, the heat transfer
units being arranged in a third direction that is different from
both of the first direction and the second direction.
[0005] In the heat exchanger according to the first aspect, the
heat transfer units are each divided into an airflow-upstream
region and an airflow-downstream region in the second direction.
When used as an evaporator, the heat exchanger according to the
first aspect causes a refrigerant to flow into a heat transfer
channel portion disposed in the airflow-upstream region, and then
causes the refrigerant to flow out to a heat transfer channel
portion disposed in the airflow-downstream region. Such a
configuration can optimize the heat exchange performance of the
entirety of the heat exchanger.
[0006] A heat exchanger according to a second aspect is the heat
exchanger according to the first aspect, in which the number of
heat transfer channel portions disposed in the airflow-downstream
region is larger than the number of heat transfer channel portions
disposed in the airflow-upstream region. Such a configuration can
realize optimal heat exchange while suppressing frosting.
[0007] A heat exchanger according to a third aspect is the heat
exchanger according to the first or second aspect, further
including a decompressing mechanism that decompresses the
refrigerant. The heat exchanger according to the third aspect
causes the refrigerant to flow from the heat transfer channel
portion disposed in the airflow-upstream region into the heat
transfer channel portion disposed in the airflow-downstream region
via the decompressing mechanism. Such a configuration can further
suppress frosting.
[0008] A heat exchanger according to a fourth aspect is the heat
exchanger according to any one of the first to third aspects,
further including an upper header and a lower header that are
connected to the heat transfer units from above and below in the
first direction and that form a part of a channel of the
refrigerant. Such a configuration can realize a heat exchanger that
can easily discharge dew condensation water.
[0009] A heat exchanger according to a fifth aspect is the heat
exchanger according to the fourth aspect, in which the
airflow-upstream region and the airflow-downstream region are
formed by a partition member (i.e., partition) disposed inside of
the upper header and/or the lower header. Accordingly, the
airflow-upstream region and the airflow-downstream region can be
easily formed.
[0010] A heat exchanger according to a sixth aspect is the heat
exchanger according to any one of the first to fifth aspects, in
which each of the heat transfer units includes at least eight or
more heat transfer channel portions, and at least two or more of
the heat transfer channel portions are disposed in the
airflow-upstream region. Such a configuration can optimize heat
exchange performance.
[0011] A heat exchanger according to a seventh aspect is the heat
exchanger according to any one of the first to sixth aspects, in
which, when seen in the first direction, a heat insulator is
applied to an end portion of each of the heat transfer units in the
second direction. Accordingly, decrease of temperature at the end
portion can be suppressed.
[0012] A heat exchanger according to an eighth aspect is the heat
exchanger according to the seventh aspect, in which, in each of the
heat transfer units, a first auxiliary heat transfer portion that
is one of the auxiliary heat transfer portions is formed at an end
portion in the second direction when seen in the first direction.
The first auxiliary heat transfer portion has a closed shape. Thus,
water drainage performance during a defrosting operation can be
increased.
[0013] An air conditioner according to a ninth aspect includes the
heat exchanger according to any one of the first to eighth
aspects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic view illustrating the concept of a
heat exchanger 10 according to one or more embodiments.
[0015] FIG. 2 is a schematic view illustrating the configuration of
the heat exchanger 10 according to one or more embodiments.
[0016] FIG. 3 is a schematic view illustrating the cross-sectional
shape of a first header 21 according to one or more
embodiments.
[0017] FIG. 4 is a schematic view illustrating the cross-sectional
shape of a second header 22 according to one or more
embodiments.
[0018] FIG. 5 is a schematic view illustrating the configuration of
a heat transfer unit 30 according to one or more embodiments.
[0019] FIG. 6 is a schematic view for describing the configuration
of the heat transfer unit 30 according to one or more
embodiments.
[0020] FIG. 7 is a schematic view for describing the configuration
of a heat transfer unit group 15 according to one or more
embodiments.
[0021] FIG. 8 is a schematic view illustrating the cross-sectional
shape of the heat exchanger 10 according to one or more
embodiments.
[0022] FIG. 9 is a view for describing a refrigerant channel of the
heat exchanger 10 according to one or more embodiments.
[0023] FIG. 10 is a view for describing the refrigerant channel of
the heat exchanger 10 according to one or more embodiments.
[0024] FIG. 11 is a schematic view illustrating the configuration
of a heat exchanger 10Z for comparison.
[0025] FIG. 12 is a view for describing a refrigerant channel of a
heat exchanger 10 according to a modification A.
[0026] FIG. 13 is a view for describing a refrigerant channel of a
heat exchanger 10Y according to a modification B.
[0027] FIG. 14 is a schematic view for describing the configuration
of a heat transfer unit group 15 according to a modification C.
[0028] FIG. 15 is a schematic view for describing the configuration
of the heat transfer unit group 15 according to a modification
C.
[0029] FIG. 16 is a schematic view for describing the configuration
of a heat transfer unit group 15 according to a modification E.
[0030] FIG. 17 is a schematic view for describing the configuration
of the heat transfer unit group 15 according to the modification E
(partial enlarged view of FIG. 16).
[0031] FIG. 18 is a schematic view for describing the configuration
of a heat transfer unit group 15 according to a modification F.
[0032] FIG. 19 is a schematic view for describing the configuration
of the heat transfer unit group 15 according to the modification F
(partial enlarged view of FIG. 18).
[0033] FIG. 20 is a schematic view for describing a heat transfer
unit group 15 according to a modification G.
[0034] FIG. 21 is a schematic view for describing the heat transfer
unit group 15 according to the modification G.
[0035] FIG. 22 is a schematic view for describing the configuration
of a heat transfer unit group 15 according to a modification H.
DETAILED DESCRIPTION
[0036] (1) Overview of Heat Exchanger
[0037] A heat exchanger 10 performs heat exchange between a fluid
that flows inside and air that flows outside. To be specific, as
conceptually illustrated in FIG. 1, a first pipe 41 and a second
pipe 42, through which a refrigerant flows into or out from the
heat exchanger 10, are attached to the heat exchanger 10. A fan 6,
for sending air to the heat exchanger 10, is disposed near the heat
exchanger 10. The fan 6 generates airflow toward the heat exchanger
10, and, when the airflow passes through the heat exchanger 10,
heat exchange is performed between the heat exchanger 10 and air.
The heat exchanger 10 functions as an evaporator that absorbs heat
from air and as a condenser (radiator) that releases heat to air,
and can be installed in an air conditioner or the like.
[0038] (2) Details of Heat Exchanger
[0039] (2-1) Overall Configuration
[0040] As illustrated in FIG. 2, the heat exchanger 10 includes a
heat transfer unit group 15, a first header 21, and a second header
22.
[0041] The heat transfer unit group 15 includes a plurality of heat
transfer units 30. The heat transfer unit group 15 is disposed so
that airflow generated by the fan 6 passes through spaces between
the heat transfer units 30. Details of the arrangement of these
members will be described below.
[0042] (2-2) Header
[0043] As illustrated in FIG. 3, the first header 21 is a hollow
member that is configured so that a refrigerant in a gas phase, a
liquid phase, and a gas-liquid two-phase can flow through the
inside thereof. The first header 21 is connected to the heat
transfer units 30 at a position above the heat transfer units 30. A
connection surface 21S, to which the heat transfer units 30 are
connected, is formed on the lower side of the first header 21.
Coupling holes, into which end portions 31e of heat transfer
channel portions 31 (described below) are inserted, are formed in
the connection surface 21S. FIG. 3 illustrates a cross section of
the first header 21 when seen in a third direction D3. The
definition of the third direction D3 will be described below.
[0044] The second header 22 is connected to the first pipe 41, the
second pipe 42, and the heat transfer unit 30 at a position below
the heat transfer units 30; and allows a refrigerant to flow into
and flow out of the first pipe 41, the second pipe 42, and the heat
transfer units 30. As with the first header 21, the second header
22 is a hollow member that is configured so that a refrigerant in a
gas phase, a liquid phase, and a gas-liquid two-phase can flow
through the inside thereof. As illustrated in FIG. 4, the second
header 22 has a partition member 22p that extends in the third
direction D3 and partitions the inside of the second header 22. In
the example shown in FIG. 4, for convenience of description, it is
assumed that the second header 22 is partitioned by the partition
member 22p into an airflow-upstream second header 22U and an
airflow-downstream second header 22L. The airflow-upstream second
header 22U and the airflow-downstream second header 22L are
respectively connected to the second header 22 and the first header
21. The partition member 22p may be integrally formed with the
second header 22 or may be formed as an independent object. A
connection surface 22S, to which the heat transfer units 30 are
connected, is formed on the upper side of the second header 22.
Coupling holes, into which end portions 31e of heat transfer
channel portions 31 (described below) are inserted, are formed in
the connection surface 22S. FIG. 4 illustrates the cross-sectional
shape of the second header 22 when seen in a third direction D3.
The definition of the third direction D3 will be described
below.
[0045] (2-3) Heat Transfer Unit
[0046] (2-3-1)
[0047] As illustrated in FIG. 5, in the heat transfer unit 30, a
plurality of heat transfer channel portions 31 and a plurality of
auxiliary heat transfer portions 32, each of which extends in a
"first direction D1", are formed so as to be arranged in a "second
direction D2" that intersects with or is perpendicular to the first
direction D1. Here, the heat transfer channel portions 31 each have
a substantially cylindrical shape, and the auxiliary heat transfer
portions 32 each have a substantially flat plate-like shape. As
illustrated in FIG. 6, the heat transfer channel portions 31 are
formed so as to be aligned in the second direction D2 at a
predetermined pitch PP. The heat transfer unit group 15 illustrated
in FIG. 7 is formed by arranging such heat transfer units 30 in a
"third direction D3" that is different from both of the first
direction D1 and the second direction D2. Here, the heat transfer
unit group 15 includes at least three or more heat transfer units
30 that are arranged in a stacked manner.
[0048] For convenience of description, it is assumed that the first
direction D1, the second direction D2, and the third direction D3
are perpendicular to each other. However, these directions D1 to D3
need not be completely perpendicular to each other, and it is
possible to realize the heat exchanger 10 according to the present
embodiment as long as these directions intersect with each
other.
[0049] The heat transfer units 30 are connected to the first header
21 and the second header 22 at the connection surfaces 21S and 22S
of the first header 21 and the second header 22. To be specific, as
illustrated in FIG. 5, at end portions of the heat transfer units
30 in the first direction D1, end portions 31e of the heat transfer
channel portions 31 protrude from end portions 32e of the auxiliary
heat transfer portions 32. The end portions 31e of the heat
transfer channel portions 31 are inserted into the coupling holes
formed in the connection surfaces 21S and 22S of the first header
21 and the second header 22. The heat transfer units 30 are fixed
in place between the first header 21 and the second header 22 by,
for example, brazing the connection portions (see FIG. 8).
[0050] The heat transfer channel portion 31 enables a refrigerant
to move between the first header 21 and the second header 22. To be
specific, a substantially cylindrical passage is formed in the heat
transfer channel portion 31, and the refrigerant moves in the
passage. The heat transfer channel portion 31 according to the
present embodiment has a linear shape in the first direction
D1.
[0051] The auxiliary heat transfer portion 32 accelerates heat
exchange between a refrigerant that flows in adjacent heat transfer
channel portions 31 and ambient air. Here, as with the heat
transfer channel portion 31, the auxiliary heat transfer portion 32
is formed so as to extend in the first direction D1 and is disposed
so as to be in contact with the adjacent heat transfer channel
portions 31. The auxiliary heat transfer portion 32 may be
integrally formed with or may be independently formed from the heat
transfer channel portions 31.
[0052] (2-3-2)
[0053] At least eight or more heat transfer channel portions 31 are
formed in the heat transfer unit 30 according to the present
embodiment. At least two or more of the heat transfer channel
portions 31 are disposed in an airflow-upstream region.
[0054] FIG. 8 illustrates an example of such a configuration. Here,
ten heat transfer channel portions 31 are formed in one heat
transfer unit 30. The inside of the second header 22 is partitioned
by the partition member 22p into the airflow-upstream second header
22U, which is disposed in an airflow-upstream region WU, and the
airflow-downstream second header 22L, which is disposed in an
airflow-downstream region WL. Three heat transfer channel portions
31U are connected to the airflow-upstream second header 22U, and
seven heat transfer channel portions 31L are connected to the
airflow-downstream second header 22L. An auxiliary heat transfer
portion 32g is formed at an end portion on the most
airflow-upstream side of the heat transfer unit 30. FIG. 8 is a
schematic view illustrating the cross-sectional shape of the heat
exchanger 10 when seen in the third direction D3.
[0055] (2-4) Refrigerant Channel
[0056] When the heat exchanger 10 is used as an evaporator, airflow
W that is generated by the fan 6 flows in the second direction D2
as illustrated in FIG. 9. In this state, a refrigerant F in a
liquid phase flows into the heat exchanger 10 from the second pipe
42. Next, the refrigerant F flows into the airflow-upstream second
header 22U from the second pipe 42. Then, as illustrated in FIG.
10, the refrigerant F flows from a lower position to an upper
position via the heat transfer channel portions 31U, which are
connected to the airflow-upstream second header 22U. Next, the
refrigerant F flows into the airflow-downstream second header 22L
via the heat transfer channel portions 31L, which are connected to
the first header 21 and the airflow-downstream second header 22L.
While the refrigerant F flows through the heat transfer channel
portions 31U and 31L, the refrigerant F exchanges heat with the
airflow W. Thus, the refrigerant F evaporates and changes into a
gas phase. Then, the refrigerant F in the gas phase flows out from
the first pipe 41. FIG. 10 illustrates a state when the heat
transfer unit 30 is seen in a third direction D3.
[0057] When the heat exchanger 10 is used as a condenser, the
refrigerant F flows in a direction opposite from that when the heat
exchanger 10 is used as an evaporator. That is, the refrigerant F
in a gas phase flows through the first pipe 41 into the heat
exchanger 10, and the refrigerant F in a liquid phase flows through
the second pipe 42 out from the heat exchanger 10.
[0058] (3) Method of Manufacturing Heat Exchanger 10
[0059] The heat transfer unit 30 is manufactured from, for example,
a metal material such as aluminum or an aluminum alloy. To be
specific, first, extrusion of a metal material is performed by
using a die corresponding to the cross-sectional shape of FIG. 5,
and the heat transfer channel portions 31 and the auxiliary heat
transfer portions 32 are integrally formed. Next, cutouts 33 are
formed by cutting off parts of the auxiliary heat transfer portions
32. The cutouts 33 are formed, for example, by punching and cutting
off a plurality of parts of the auxiliary heat transfer portions
32.
[0060] The first header 21 and the second header 22 are
manufactured by processing a metal material into a tubular shape.
Coupling holes for inserting the end portions 31e of the heat
transfer channel portions 31 are formed in the first header 21 and
the second header 22. The coupling holes are circular through-holes
that are formed by using, for example, a drill.
[0061] In assembling the heat exchanger 10, the end portions 31e of
the heat transfer channel portions 31 of the heat transfer units 30
are inserted into the coupling holes of the first header 21 and the
second header 22. Thus, the end portions 32e of the auxiliary heat
transfer portions 32 are brought into contact with the connection
surfaces 21S and 22S of the first header 21 and the second header
22. At the contact portions, the heat transfer units 30, the first
header 21, and the second header 22 are fixed by, for example,
brazing.
[0062] (4) Features
[0063] (4-1)
[0064] As heretofore described, the heat exchanger 10 according to
the present embodiment includes the heat transfer unit 30 in which
the plurality of heat transfer channel portions 31 and the
plurality of auxiliary heat transfer portions 32, each of which
extends in the first direction D1, are formed so as to be arranged
in the second direction D2 that intersects with or is perpendicular
to the first direction D1. Here, a plurality of heat transfer units
30 are arranged in the third direction D3 that is different from
both of the first direction D1 and the second direction D2, and
form the heat transfer unit group 15.
[0065] In the heat exchanger 10 according to the present
embodiment, the heat transfer units 30 are each divided into the
airflow-upstream region WU and the airflow-downstream region WL in
the second direction D2. When used as an evaporator, the heat
exchanger 10 causes a refrigerant F to flow into the heat transfer
channel portions 31U disposed in the airflow-upstream region WU,
and then causes the refrigerant F to flow out to the heat transfer
channel portions 31L disposed in the airflow-downstream region
WL.
[0066] In short, in the heat exchanger 10 according to the present
embodiment, the refrigerant channel is folded back at least once in
the second direction D2 in which airflow W is generated. Thus, a
heat exchanger having high heat exchange performance can be
provided.
[0067] To be more specific, for example, with a heat exchanger 10Z
illustrated in FIG. 11, which is configured to cause a refrigerant
F to flow through the heat transfer units 30Z only once from a
lower position to an upper position in the first direction D1, when
used as an evaporator in a low temperature environment (for
example, 7.degree. C. or lower), frosting may occur between the
heat transfer units 30Z, because the heat transfer amount in the
heat transfer channel portions on the airflow-upstream side is
large. Moreover, blockage of the air passage may occur due to
frosting. A partition member or the like is not provided inside of
a first header 21Z and a second header 22Z illustrated in FIG.
11.
[0068] In contrast, with the configuration of the heat exchanger 10
according to the present embodiment, because the number of channels
of a refrigerant F flowing from the second pipe 42 is limited to
the number of the airflow-upstream heat transfer channel portions
31U, pressure loss of the refrigerant occurs. Due to the pressure
loss, the refrigerant temperature in the airflow-upstream heat
transfer channel portions 31U increases. Therefore, when the heat
exchanger 10 is used as an evaporator, the heat exchange amount in
the airflow-upstream heat transfer channel portions 31U is
suppressed. Thus, variation of heat flux in accordance with the
position in the heat transfer unit group 15 can be suppressed. As a
result, when the heat exchanger 10 is used as an evaporator in a
low temperature environment (for example, 7.degree. C. or lower),
local occurrence of frosting can be avoided, and a heat exchanger
having high heat exchange performance can be provided.
[0069] With the heat exchanger 10Z having the configuration
illustrated in FIG. 11, due to the front-edge effect of the
auxiliary heat transfer portions on the most airflow-upstream side,
the heat exchange amount of the heat transfer channel portions on
the airflow-upstream side is large, compared with the heat exchange
amount of the heat transfer channel portions on the
airflow-downstream side. Therefore, when the refrigerant F flowing
from the second pipe 42 is caused to flow to a plurality of heat
transfer channel portions, the refrigerant F may completely
evaporate in the heat transfer channel portions on the
airflow-upstream side. As a result, sufficient heat exchange may
not be performed in the heat exchanger 10Z.
[0070] In contrast, with the configuration of the heat exchanger
according to the present embodiment, because all of the refrigerant
F flowing from the second pipe 42 is caused to temporarily flow to
the airflow-upstream heat transfer channel portions 31U, the
refrigerant is prevented from completely evaporating in the
airflow-upstream heat transfer channel portions 31U. As a result,
the heat exchange performance of the heat exchanger 10 can be
optimized.
[0071] (4-2)
[0072] In the heat exchanger 10 according to the present
embodiment, the number of heat transfer channel portions 31L
disposed in the airflow-downstream region WL is larger than the
number of heat transfer channel portions 31U disposed in the
airflow-upstream region WU. Each of the heat transfer units 30
includes at least eight or more heat transfer channel portions 31,
and at least two or more heat transfer channel portions 31U are
disposed in the airflow-upstream region WU. With such a
configuration, when the heat exchanger 10 is used as an evaporator
in a low temperature environment (for example, 7.degree. C. or
lower), optimal heat exchange can be realized, while suppressing
occurrence of frosting.
[0073] (4-3)
[0074] The heat exchanger 10 according to the present embodiment
further includes the first header 21 (upper header) and the second
header 22 (lower header) that are connected to the heat transfer
units 30 from above and below in the first direction D1 and that
form a part of the refrigerant channel. With such a configuration,
the longitudinal direction of the heat transfer units 30 can be
directed in the vertical direction, and water adhered to the heat
transfer units 30 (dew condensation water and the like) can be
easily discharged. Moreover, ease of assembling and processing can
be also increased.
[0075] However, the heat exchanger 10 according to the present
embodiment does not exclude a configuration such that the first
header 21 and the second header 22 are arranged in the left-right
direction instead of the up-down direction.
[0076] (4-4)
[0077] In the heat exchanger 10 according to the present
embodiment, the airflow-upstream region WU and the
airflow-downstream region WL are formed by the partition member 22p
disposed inside of the second header 22 (lower header). Thus, the
airflow-upstream region WU and the airflow-downstream region WL can
be easily formed without performing special processing or the like
on the heat transfer units 30.
[0078] In the heat exchanger 10 according to the present
embodiment, a partition member may be provided in the first header
21, instead of in the second header 22, in accordance with the flow
path of refrigerant. Alternatively, partition members may be
provided in both of the first header 21 and the second header 22,
in accordance with the flow path of refrigerant.
[0079] (4-5)
[0080] In the heat exchanger 10 according to the present
embodiment, each heat transfer unit 30 can be formed from a single
member by extrusion of a metal material. The plurality of cutouts
33 can be simultaneously formed by punching. Accordingly, it is
possible to provide the heat exchanger 10 that can be easily
assembled and processed.
[0081] (5) Modifications
[0082] (5-1) Modification A
[0083] A heat exchanger 10 according to the present embodiment may
further include a decompressing mechanism that decompresses a
refrigerant. To be specific, as conceptually illustrated in FIG.
12, the heat exchanger 10 may include a decompressing mechanism 25,
which is an electromagnetic valve or the like, between the
refrigerant channel (heat transfer channel portions 31U) in the
airflow-upstream region WU and the refrigerant channel (heat
transfer channel portions 31L) in the airflow-downstream region WL.
Because the decompressing mechanism 25 expands the refrigerant F,
the refrigerant temperature in the airflow-upstream region can be
optimized. As a result, when the heat exchanger 10 is used as an
evaporator in a low temperature environment (for example, 7.degree.
C. or lower), occurrence of frosting can be further suppressed.
[0084] (5-2) Modification B
[0085] A heat exchanger 10 according to the present embodiment is
not limited to the configuration described above. That is, the heat
exchanger 10 according to the present embodiment may have any
configuration in which the refrigerant channel is folded back at
least once in the second direction D2 in which airflow W is
generated. For example, a heat exchanger 10Y having a refrigerant
channel as illustrated in FIG. 13 may be used. FIG. 13 is a
schematic view for describing the refrigerant channel formed in the
heat exchanger 10Y.
[0086] In the example illustrated in FIG. 13, near a middle portion
of the airflow-upstream second header 22U, a partition member 22ps
is provided inside of the airflow-upstream second header 22U in the
second direction D2. Thus, the airflow-upstream second header 22U
is partitioned into two regions, which are an airflow-upstream
upstream second header 22UA and an airflow-upstream downstream
second header 22UB. In the example illustrated in FIG. 13, a
partition member 21p and the like are disposed inside of the first
header 21, and the first header 21 is partitioned into an
airflow-upstream first header 21U and an airflow-downstream first
header 21L in the second direction D2. With the heat exchanger 10Y
having such a configuration, a refrigerant F that has flowed into
the airflow-upstream upstream second header 22UA from the second
pipe 42 flows into the airflow-upstream first header 21U through
the heat transfer channel portions in the airflow-upstream upstream
region. Next, the refrigerant F flows into the heat transfer
channel portions in the airflow-upstream downstream region via the
airflow-upstream first header 21U. The refrigerant that has flowed
into the airflow-upstream downstream second header 22UB flows into
the airflow-downstream second header 22L via a connection pipe and
the like (not shown). The refrigerant F that has flowed into the
airflow-downstream second header 22L flows into the first pipe 41
via the airflow-downstream first header 21L. In the heat exchanger
10Y, the first pipe 41 is connected to the airflow-downstream first
header 21L.
[0087] Also with the heat exchanger 10Y having such a
configuration, advantageous effects that are the same as those
described above are realized, because the refrigerant channel is
folded back at least once in the second direction D2 in which
airflow W is generated.
[0088] (5-3) Modification C
[0089] In the heat exchanger 10 according to the present
embodiment, when seen in the first direction D1, a heat insulator I
may be applied to an end portion of the heat transfer unit 30 on
the airflow-upstream side in the second direction D2 (here, the
auxiliary heat transfer portion 32g) (see FIGS. 14 and 15). Thus,
decrease of temperature at the end portion can be suppressed. As a
result, when the heat exchanger 10 is used as an evaporator in a
low temperature environment (for example, 7.degree. C. or lower),
frosting can be suppressed, and blockage of the air passage can be
avoided or retarded.
[0090] In the example illustrated in FIGS. 14 and 15, the end
portion of the heat transfer unit 30 is the auxiliary heat transfer
portion 32g. Moreover, the auxiliary heat transfer portion 32g on
the most airflow-upstream side (first auxiliary heat transfer
portion) has a closed shape. Here, the term "closed shape" refers
to a flat shape without a hole or a cutout. Thus, water-drainage
performance during a defrosting operation can be further
increased.
[0091] To be more specific, if a hole, a cutout, or the like is
formed in the auxiliary heat transfer portion 32g, water generated
by defrosting may be retained in the hole, the cutout, or the like.
In this case, next frosting may spread from a portion where water
is retained. In contrast, with the heat exchanger 10 according to
the modification C, because the auxiliary heat transfer portion 32g
has a shape without a hole, a cutout, or the like, occurrence of
frosting after a defrosting operation can be suppressed.
[0092] (5-4) Modification D
[0093] The heat transfer channel portion 31 according to the
present embodiment is not limited to the one described above, and
may have another configuration. For example, the cross-sectional
shape of the heat transfer channel portions 31 when seen in the
first direction D1 may be any of: a semicircular shape, an
elliptical shape, a flat shape, a shape like an upper half of an
airfoil, and/or a shape like a lower half of an airfoil; or any
combination of these. In short, the heat exchanger 10 may have any
shape that optimizes heat exchange performance.
[0094] (5-5) Modification E The heat transfer unit group 15
according to the present embodiment may have a configuration as
illustrated in FIGS. 16 and 17. FIG. 17 is a partial enlarged view
of FIG. 16 (corresponding to a dotted-line part of FIG. 16).
[0095] In the example illustrated in FIGS. 16 and 17, the heat
transfer unit 30 (including 30a, 30b, and 30c) includes a first
bulging portion 31p (including 31pa, 31pb, and 31pc) that bulges at
a first position L1 (including L1a, L1b, and L1c) in the second
direction D2 and forms the heat transfer channel portion 31, and a
first flat surface portion 31q (including 31qa, 31qb, and 31qc)
that is formed at the first position L1 so as to face in a
direction opposite from the direction in which the first bulging
portion 31p is formed. In the modification E, the "first position"
is defined for each heat transfer unit, and the first position L1a
of the heat transfer unit 30a and the first positions Lib and L1c
of the heat transfer units 30b and 30c are different positions.
[0096] Moreover, at least one heat transfer unit 30a is disposed in
a direction such that, with respect to a heat transfer unit 30b
adjacent on one side, a surface on which the first bulging portion
31pa is formed and a surface of the adjacent heat transfer unit 30b
on which the first bulging portion 31pb is formed face each other.
The heat transfer unit 30a is disposed in a direction such that,
with respect to the heat transfer unit 30c adjacent on the other
side, a surface on which the first flat surface portion 31qa is
formed and a surface of the other heat transfer unit 30c on which
the first flat surface portion 31qc is formed face each other.
[0097] With such a configuration, when the heat exchanger 10 is
used as an evaporator, because airflow straightly passes through an
air passage in which the first flat surface portions 31qa and 31qc
face each other, the generation amount of frost can be suppressed.
Thus, heat exchange performance can be increased depending on a use
environment.
[0098] In an air passage in which the first bulging portions 31pa
and 31pb face each other, contraction flow of airflow occurs, and
frost is likely to concentratedly occur in the air passage.
However, even if such frosting occurs, depending on a use
environment, the heat exchange performance of the entirety of the
heat exchanger can be increased, compared with a heat exchanger in
which substantially the same bulging portions are formed on both
surfaces of the heat transfer units as illustrated in FIG. 7.
[0099] Moreover, as illustrated in FIG. 17, in the heat exchanger
according to the modification E, when seen in the first direction
D1, the first positions L1a and L1b of the adjacent heat transfer
units 30a and 30b are arranged so as not to overlap. In other
words, in the air passage between the adjacent heat transfer units
30a and 30b, the first bulging portions 31pa and 30pb are arranged
in a staggered pattern. Therefore, the channel cross-sectional area
of the air passage between the adjacent heat transfer units 31a and
31b can be increased, compared with a configuration in which the
bulging portions are disposed close to each other as illustrated in
FIG. 7. Accordingly, when the heat exchanger 10 is used as an
evaporator in a low temperature environment (for example, 7.degree.
C. or lower), blockage of the air passage due to frosting can be
further suppressed.
[0100] Furthermore, the heat transfer unit 30 may have a second
bulging portion that bulges to a smaller degree than the first
bulging portion 31p, instead of the first flat surface portion 31q.
An argument similar to that described above also applies to this
case.
[0101] (5-6) Modification F
[0102] The heat transfer unit group 15 according to the present
embodiment may have a configuration as illustrated in FIGS. 18 and
19. FIG. 19 is a partial enlarged view of FIG. 18 (corresponding to
a dotted-line part of FIG. 18).
[0103] In the example illustrated in FIGS. 18 and 19, the heat
transfer unit 30 (including 30a, 30b, and 30c) includes: a first
bulging portion 31p (including 31pa, 31pb, and 31pc) that bulges at
a first position L1 (including L1a, L1b, and L1c) in the second
direction D2 and forms the heat transfer channel portion 31; a
first flat surface portion 31q (including 31qa, 31qb, and 31qc)
that is formed at the first position L1 so as to face in a
direction opposite from the direction in which the first bulging
portion 31p is formed; a third bulging portion 31r (including 31ra,
31rb, and 31rc) that bulges at a second position L2 (including L2a,
L2b, and L2c) in the second direction D2 so as to face in a
direction opposite from the direction in which the first bulging
portion 31p is formed, and that forms the heat transfer channel
portion 31; and a second flat surface portion 31s (including 31sa,
31sb, and 31sc) that is formed at the second position L2 so as to
face in a direction opposite from the direction in which the third
bulging portion 31r is formed. Here, the first bulging portion 31p
and the third bulging portion 31r have the same shape. The first
bulging portion 31p and the third bulging portion 31r are adjacent
to each other in the second direction D2.
[0104] Moreover, at least one heat transfer unit 30a is disposed in
a direction such that, with respect to a heat transfer unit 30b
adjacent on one side, a surface on which the first bulging portion
31pa is formed and a surface of the adjacent heat transfer unit 30b
on which the first flat portion 31qb is formed face each other. The
heat transfer unit 30a is disposed in a direction such that, with
respect to the heat transfer unit 30c adjacent on the other side, a
surface on which the third bulging portion 31ra is formed and a
surface of the other adjacent heat transfer unit 30c on which the
second flat surface portion 30sc is formed face each other.
[0105] Furthermore, the first positions L1a and L1b (or L1a and
L1c) in the adjacent heat transfer units 30a and 30b (or 30a and
30c) are arranged so as to overlap when seen in the first direction
D1. The second positions L2a and L2b (or L2a and L2c) are arranged
so as to overlap when seen in the first direction D1. To be more
specific, although the "first position L1" and the "second position
L2" are defined for each heat transfer unit, here, these positions
are the same in the heat transfer units 30a, 30b, and 30c.
[0106] In short, in the heat exchanger 10 according to the
modification F, between adjacent heat transfer units 30a and 30b,
the first bulging portions 31pa and 31pb and the like do not face
each other, but are formed in opposite directions. Therefore,
compared with a configuration in which the first bulging portions
31pa and 31pb and the like face each other, occurrence of
contraction can be suppressed. As a result, it is possible to
suppress increase of airflow resistance, and to realize optimal
heat exchange performance. With the heat exchanger 10 having a
configuration described above, when used as an evaporator (for
example, 7.degree. C. or lower), local frosting can be suppressed,
compared with a heat exchanger in which substantially the same
bulging portions are formed on both sides of the heat transfer
units as illustrated in FIG. 7.
[0107] The heat transfer unit 30 may have a second bulging portion
that bulges to a smaller degree than the first bulging portion 31p,
instead of the first flat surface portion 31q, and may have a
fourth bulging portion that bulges to a smaller degree than the
third bulging portion 31r, instead of the second flat surface
portion 31s. An argument similar to that described above also
applies to these cases.
[0108] (5-7) Modification G
[0109] In the heat exchanger 10 according to the present
embodiment, as illustrated in FIG. 20, when seen in the first
direction D1, an auxiliary heat transfer portion 32g (first
auxiliary heat transfer portion) that is longer than the other
auxiliary heat transfer portions 32 may be formed at an end portion
of the heat transfer unit 30 in the second direction D2. With such
a heat exchanger 10, because the distance between the heat transfer
channel portion 31g on the most airflow-upstream side and an
adjacent auxiliary heat transfer portion 32g is large, the amount
of heat transferred from the heat transfer channel portion 31g on
the most airflow-upstream side to the auxiliary heat transfer
portion 32g can be reduced. Thus, heat flux distribution on the
surface of the heat transfer unit 30 can be made uniform. As a
result, when the heat exchanger 10 is used as an evaporator in a
low temperature environment (for example, 7.degree. C. or lower),
local occurrence of frosting at an inlet portion of the air passage
can be suppressed or avoided.
[0110] Moreover, in the heat exchanger 10 according to the present
embodiment, as illustrated in FIG. 21, end portions of adjacent
heat transfer units 30 may be arranged in a staggered pattern so
that the lengths of the auxiliary heat transfer portions 32g in the
second direction D2 differ from each other between the adjacent
heat transfer units 30. In such a heat exchanger, a portion having
a large area is formed at an inlet portion of the air passage.
Accordingly, when the heat exchanger 10 is used as an evaporator in
a low temperature environment (for example, 7.degree. C. or lower),
frosting at the inlet portion of the air passage can be suppressed
or avoided.
[0111] (5-8) Modification H
[0112] As illustrated in FIG. 22, in the heat exchanger 10
according to the present embodiment, when seen in the first
direction D1, the heat transfer unit 30 may be processed so as to
have a wave-like shape in addition to a linear shape. When the heat
transfer unit 30 has a linear shape, air passage resistance can be
suppressed. On the other hand, when the heat transfer units 30 has
a wave-like shape, heat exchange amount between airflow and a
refrigerant can be increased. In short, it is possible to provide a
heat exchanger having optimal heat exchange performance in
accordance with a use environment.
[0113] (5-9) Modification I
[0114] The heat exchanger 10 according to the present embodiment
can be applied to a vessel heat exchanger (small-diameter
multi-pipe heat exchanger) in which heat transfer tubes and fins
are arranged in one direction although it is not limited to this
configuration. For example, application to a microchannel heat
exchanger (flat multi-hole-pipe heat exchanger) is also
possible.
OTHER EMBODIMENTS
[0115] Heretofore, embodiments have been described, and it should
be understood that the configurations and details may be modified
in various ways within the sprit and scope of the claims.
[0116] Although the disclosure has been described with respect to
only a limited number of embodiments, those skilled in the art,
having benefit of this disclosure, will appreciate that various
other embodiments may be devised without departing from the scope
of the present invention. Accordingly, the scope of the invention
should be limited only by the attached claims.
REFERENCE SIGNS LIST
[0117] 10 heat exchanger [0118] 21 first header (upper header)
[0119] 21p partition member [0120] 22 second header (lower header)
[0121] 22p partition member [0122] 22ps partition member [0123] 25
decompressing mechanism [0124] 30 heat transfer unit [0125] 30a
heat transfer unit (one heat transfer unit) [0126] 30b heat
transfer unit (heat transfer unit adjacent on one side) [0127] 30c
heat transfer unit (heat transfer unit adjacent on the other side)
[0128] 31p heat transfer channel portion [0129] 31p first bulging
portion [0130] 31q first flat surface portion [0131] 31r third
bulging portion [0132] 31s second flat surface portion [0133] 31L
airflow-downstream heat transfer channel portion [0134] 31U
airflow-upstream heat transfer channel portion [0135] 32 auxiliary
heat transfer portion [0136] 32g auxiliary heat transfer portion at
end portion in second direction (first auxiliary heat transfer
portion) [0137] D1 first direction [0138] D2 second direction
[0139] D3 third direction [0140] I heat insulator [0141] L1 first
position [0142] L2 second position [0143] WL airflow-downstream
region [0144] WU airflow-upstream region
Patent Literature
[0145] Patent Literature 1: Japanese Unexamined Patent Application
Publication No. 2006-90636
* * * * *