U.S. patent application number 14/394124 was filed with the patent office on 2015-02-26 for heat exchanger header, heat exchanger having the heat exchanger header, refrigeration cycle apparatus and air-conditioning apparatus.
The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Akira Ishibashi, Sangmu Lee, Takuya Matsuda, Takashi Okazaki.
Application Number | 20150053384 14/394124 |
Document ID | / |
Family ID | 49482333 |
Filed Date | 2015-02-26 |
United States Patent
Application |
20150053384 |
Kind Code |
A1 |
Ishibashi; Akira ; et
al. |
February 26, 2015 |
HEAT EXCHANGER HEADER, HEAT EXCHANGER HAVING THE HEAT EXCHANGER
HEADER, REFRIGERATION CYCLE APPARATUS AND AIR-CONDITIONING
APPARATUS
Abstract
A heat exchanger header for a heat exchanger in which
refrigerant is flowed in parallel through a plurality of flat tubes
disposed in parallel includes a header main body in which a
plurality of through-holes are arranged side by side in a
longitudinal direction, and a lid body that is joined to the header
main body. At least one chamber communicating with the plurality of
through-holes and serving as a refrigerant flow passage is formed
between the header main body and the lid body. Each of the
plurality of through-holes is an inlet side through-hole or an
outlet side through-hole to which a refrigerant inlet side end or a
refrigerant outlet side end of the plurality of flat tubes is
connected. In a part of the lid body that faces the inlet side
through-holes, a plurality of grooves are formed in a lateral
direction perpendicular to the longitudinal direction.
Inventors: |
Ishibashi; Akira; (Tokyo,
JP) ; Matsuda; Takuya; (Tokyo, JP) ; Lee;
Sangmu; (Tokyo, JP) ; Okazaki; Takashi;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
49482333 |
Appl. No.: |
14/394124 |
Filed: |
April 23, 2013 |
PCT Filed: |
April 23, 2013 |
PCT NO: |
PCT/JP2013/061858 |
371 Date: |
October 13, 2014 |
Current U.S.
Class: |
165/173 |
Current CPC
Class: |
F28D 2021/0071 20130101;
F28F 9/0268 20130101; F28F 9/02 20130101; F28F 2009/0292 20130101;
F28F 9/0265 20130101; F28D 7/16 20130101 |
Class at
Publication: |
165/173 |
International
Class: |
F28F 9/02 20060101
F28F009/02; F28D 7/16 20060101 F28D007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2012 |
JP |
PCT/JP2012/002879 |
Claims
1. A heat exchanger header for a heat exchanger in which a
refrigerant is flowed in parallel through a plurality of heat
transfer tubes disposed in parallel, the heat exchanger header
being configured to distribute the refrigerant to the plurality of
heat transfer tubes in parallel by effect of surface tension,
wherein a plurality of through-holes to which ends of the plurality
of heat transfer tubes are connected are arranged side by side in a
longitudinal direction, wherein at least one chamber communicating
with the plurality of through-holes and serving as a refrigerant
flow passage is formed, and wherein each of the plurality of
through-holes is either of an inlet side through-hole and an outlet
side through-hole to which a refrigerant inlet side end and a
refrigerant outlet side end, respectively, of the plurality of heat
transfer tubes are connected, and in a part of the chamber that
faces the inlet side through-holes, a plurality of grooves
extending in the longitudinal direction of the header are formed in
a lateral direction perpendicular to the longitudinal
direction.
2. The heat exchanger header of claim 1, wherein the at least one
chamber comprises a plurality of chambers separated in the
longitudinal direction of the header, each of the plurality of
chambers is classified as any one of an inflow chamber into which
the refrigerant from outside flows, a U-turn chamber serving as a
U-turn flow passage, and an outflow chamber from which refrigerant
flows to the outside, wherein through-holes communicating with the
inflow chamber are all inlet side through-holes, and the plurality
of grooves are formed over an entire length in the longitudinal
direction of the part forming the inflow chamber, wherein
through-holes communicating with the U-turn chamber are divided
into an inlet side through-hole group and an outlet side
through-hole group, and the plurality of grooves are formed in a
part facing the inlet side through-hole group, and wherein
through-holes communicating with the outflow chamber are all outlet
side through-holes, and the plurality of grooves are not formed in
a part forming the outflow chamber.
3. The heat exchanger header of claim 2, wherein the plurality of
grooves are formed by gaps between a plurality of protruding
protrusions, and every two of the plurality of protrusions formed
in the U-turn chamber that are adjacent in the lateral direction
differ in a position of an end closest to a border between the
inlet side through-hole group and the outlet side through-hole
group.
4. The heat exchanger header of claim 1, wherein the plurality of
grooves are formed by gaps between a plurality of protruding
protrusions, and every adjacent two of the plurality of protrusions
differ in height.
5. The heat exchanger header of claim 4, wherein heights of the
plurality of protrusions are alternately large and small in the
lateral direction.
6. The heat exchanger header of claim 4, wherein heights of the
plurality of protrusions are configured to be increasingly large
toward a central part in the lateral direction.
7. The heat exchanger header of claim 1, wherein the header
includes a header main body that has a box-like shape with one side
open and whose bottom surface facing the opening has the plurality
of through-holes formed therein, and a lid body formed in a
plate-like shape covering the opening.
8. The heat exchanger header of claim 7, wherein the grooves are
formed in the lid body.
9. A heat exchanger comprising a heat exchanger header in which
refrigerant is flowed in parallel through a plurality of heat
transfer tubes disposed in parallel, the heat exchanger header
being configured to distribute the refrigerant to the plurality of
heat transfer tubes in parallel by effect of surface tension,
wherein a plurality of through-holes to which ends of the plurality
of heat transfer tubes are connected are arranged side by side in a
longitudinal direction, wherein at least one chamber communicating
with the plurality of through-holes and serving as a refrigerant
flow passage is formed, and wherein each of the plurality of
through-holes is an inlet side through-hole or an outlet side
through-hole to which a refrigerant inlet side end or a refrigerant
outlet side end of the plurality of heat transfer tubes is
connected, and in a part of the chamber that faces the inlet side
through-holes, a plurality of grooves extending in the longitudinal
direction of the header are formed in a lateral direction
perpendicular to the longitudinal direction.
10. A heat exchanger comprising, in an air passing direction, at
least two heat exchanging units including a pair of the heat
exchanger headers of claim 2 spaced from each other in a direction
perpendicular to the air passage direction, a plurality of heat
transfer tubes disposed in parallel between the pair of heat
exchanger headers and both ends of which are connected to the
plurality of through-holes of the pair of heat exchanger headers,
and a plurality of fins disposed such that air passes in the air
passage direction, wherein the heat exchanging units are connected
by an inter-line pipe, and a refrigerant flow passage is formed in
which the refrigerant flows through the plurality of heat transfer
tubes of the heat exchanging unit on an upstream side in the air
passage direction, from the inflow chamber to the outflow chamber
while making a U-turn in the U-turn chamber, then flows through the
inter-line pipe into the heat exchanging unit on a downstream side
in the air passage direction, and flows from the inflow chamber to
the outflow chamber of the heat exchanger header while making a
U-turn in the U-turn chamber, and wherein when the heat exchanger
is used as an evaporator, a number of refrigerant passes of the
refrigerant flowing through the heat exchanging unit on the
upstream side is less than a number of refrigerant passes of the
refrigerant flowing through the heat exchanging unit on the
downstream side.
11. The heat exchanger of claim 9, wherein the heat transfer tubes
are flat tubes having a plurality of through-holes serving as
refrigerant flow passages.
12. A refrigeration cycle apparatus comprising a heat exchanger
comprising a heat exchanger header in which refrigerant is flowed
in parallel through a plurality of heat transfer tubes disposed in
parallel, the heat exchanger header being configured to distribute
the refrigerant to the plurality of heat transfer tubes in parallel
by effect of surface tension, wherein a plurality of through-holes
to which ends of the plurality of heat transfer tubes are connected
are arranged side by side in a longitudinal direction, at least one
chamber communicating with the plurality of through-holes and
serving as a refrigerant flow passage is formed, and each of the
plurality of through-holes is an inlet side through-hole or an
outlet side through-hole to which a refrigerant inlet side end or a
refrigerant outlet side end of the plurality of heat transfer tubes
is connected, and in a part of the chamber that faces the inlet
side through-holes, a plurality of grooves extending in the
longitudinal direction of the header are formed in a lateral
direction perpendicular to the longitudinal direction.
13. An air-conditioning apparatus comprising a heat exchanger
comprising a heat exchanger header in which refrigerant is flowed
in parallel through a plurality of heat transfer tubes disposed in
parallel, the heat exchanger comprising a heat exchange header, the
heat exchanger header being configured to distribute the
refrigerant to the plurality of heat transfer tubes in parallel by
effect of surface tension, wherein a plurality of through-holes to
which ends of the plurality of heat transfer tubes are connected
are arranged side by side in a longitudinal direction, at least one
chamber communicating with the plurality of through-holes and
serving as a refrigerant flow passage is formed, and each of the
plurality of through-holes is an inlet side through-hole or an
outlet side through-hole to which a refrigerant inlet side end or a
refrigerant outlet side end of the plurality of heat transfer tubes
is connected, and in a part of the chamber that faces the inlet
side through-holes, a plurality of grooves extending in the
longitudinal direction of the header are formed in a lateral
direction perpendicular to the longitudinal direction.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a U.S. national stage application of
PCT/JP2013/061858 filed on Apr. 23, 2013, which claims priority to
international application no. PCT/JP2012/002879, filed on Apr. 26,
2012, the contents of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a heat exchanger header for
a heat exchanger used in a refrigeration cycle apparatus such as an
air-conditioning apparatus, and a heat exchanger having the heat
exchanger header, a refrigeration cycle apparatus and an
air-conditioning apparatus.
BACKGROUND
[0003] Hitherto, there has been a heat exchanger configured such
that a pair of headers extending in the vertical direction are
spaced in the lateral direction, a plurality of flat tubes are
disposed in parallel between the pair of headers, and both ends of
the plurality of heat exchanging tubes communicate with the
plurality of headers. In this type of heat exchanger, when it is
used as an evaporator, two-phase gas-liquid refrigerant flows into
it, and therefore liquid is accumulated in the gravity direction in
an inlet side header, whereas gas is accumulated in the upper part
in the header. Therefore, there is a problem that refrigerant
cannot be equally distributed to each flat tube, and the
performance of the heat exchanger degrades.
[0004] So, when a heat exchanger is used as an evaporator, an inlet
side header is required to have a function of equally distributing
refrigerant. As a header having such a function, hitherto, there
has been a header in which a looped flow passage that makes a
U-turn in the vertical direction is formed in the header, and an
incoming two-phase refrigerant flow is circulated and homogenized
in the header, and is distributed to each of a plurality of heat
transfer tubes (see, for example, Patent Literature 1).
PATENT LITERATURE
[0005] Patent Literature 1: Japanese Unexamined Patent Application
Publication No. 2011-85324 (Abstract, FIG. 1)
[0006] However, in the header of Patent Literature 1, since
refrigerant is passed through a looped flow passage, there is a
problem that pressure loss occurs, and results in a degradation of
the heat transfer performance of the heat exchanger.
[0007] In addition, in the header of Patent Literature 1, since it
is necessary to separately form a looped flow passage inside the
header, there is a problem that the complicated structure results
in an increase in cost.
SUMMARY
[0008] The present invention has been made in view of such points,
and it is an object of the present invention to provide a heat
exchanger header that can suppress pressure loss, can equally
distribute refrigerant without degrading heat transfer performance
of a heat exchanger, and has a simple structure, and a heat
exchanger having the heat exchanger header, a refrigeration cycle
apparatus and an air-conditioning apparatus.
[0009] A heat exchanger header according to the present invention
is a heat exchanger header for a heat exchanger in which
refrigerant is flowed in parallel through a plurality of heat
transfer tubes disposed in parallel, the heat exchanger header
being configured to distribute the refrigerant to the plurality of
heat transfer tubes in parallel by effect of surface tension,
wherein a plurality of through-holes to which ends of the plurality
of heat transfer tubes are connected are arranged side by side in a
longitudinal direction, wherein at least one chamber communicating
with the plurality of through-holes and serving as a refrigerant
flow passage is formed, and wherein each of the plurality of
through-holes is an inlet side through-hole or an outlet side
through-hole to which a refrigerant inlet side or refrigerant
outlet side end of the plurality of heat transfer tubes is
connected, and in a part of the chamber that faces the inlet side
through-holes, a plurality of grooves extending in the longitudinal
direction of the header are formed in a lateral direction
perpendicular to the longitudinal direction.
[0010] According to the present invention, a heat exchanger header
that can suppress pressure loss, can equally distribute refrigerant
without degrading heat transfer performance of a heat exchanger,
and has a simple structure can be obtained.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a schematic front view of a heat exchanger 1
employing a heat exchanger header according to Embodiment 1 of the
present invention.
[0012] FIG. 2 is a perspective view showing one of the flat tubes
30 of FIG. 1.
[0013] FIG. 3 is an exploded perspective view of the inlet header
10 of FIG. 1.
[0014] FIG. 4 is a sectional view of the inlet header part of FIG.
1 taken along line A-A.
[0015] FIG. 5 is a diagram showing a refrigerant circuit of a
refrigeration cycle apparatus 50 to which the heat exchanger 1 of
FIG. 1 is applied.
[0016] FIG. 6 is a diagram showing the flow of refrigerant in the
case where the heat exchanger 1 of FIG. 1 is used as an
evaporator.
[0017] FIG. 7 is a diagram showing the flow state of refrigerant in
the inlet header 10.
[0018] FIG. 8 is a sectional view taken along line B-B of FIG.
7.
[0019] FIG. 9 shows the flow state of refrigerant in a header not
provided with grooves as a comparative example.
[0020] FIG. 10 is a diagram showing Modification 1 of the grooves
14 of FIG. 3.
[0021] FIG. 11 is a diagram showing Modification 2 of the grooves
14 of FIG. 3.
[0022] FIG. 12 is a diagram showing a heat exchanger 1A according
to Embodiment 2 of the present invention.
[0023] FIG. 13 is an exploded perspective view of the header 70 of
FIG. 124.
[0024] FIG. 14 shows modifications of the grooves 14 of FIG.
13.
[0025] FIG. 15 shows a heat exchanger 1B according to Embodiment 3
of the present invention.
DETAILED DESCRIPTION
Embodiment 1
[0026] FIG. 1 is a schematic perspective view of a heat exchanger
employing a heat exchanger header according to Embodiment 1 of the
present invention. In FIG. 1 and the other figures described later,
the same reference signs are used for the same or corresponding
components, and this is common throughout the specification. The
forms of components described in the whole specification are
illustrative only, and the present invention is not limited to
these descriptions.
[0027] The heat exchanger 1 is a parallel flow heat exchanger in
which refrigerant is flowed in parallel, particularly a one-way
flow passage type heat exchanger in which refrigerant is flowed
from one side to the other side in the whole heat exchanger 1. The
heat exchanger 1 has a pair of headers 10 and 20 spaced from each
other, a plurality of flat tubes (heat transfer tubes) 30 that are
disposed in parallel between the pair of headers 10 and 20 and both
ends of which are connected to the pair of headers 10 and 20, and a
plurality of fins 40. The pair of headers 10 and 20, the flat tubes
30, and the fins 40 are all formed of aluminum or aluminum
alloy.
[0028] The fins 40 are plate-like fins that are stacked at
intervals between the pair of headers 10 and 20 and between which
air passes, and the plurality of flat tubes 30 are passed
therethrough. The fins 40 do not necessarily have to be plate-like
fins, and only have to be fins 40 disposed such that air passes in
the air passage direction. The fins 40 may be, for example,
corrugated fins or the like alternately stacked with the flat tubes
30 in the vertical direction. In short, the fins 40 only have to be
fins disposed such that air passes in the air passage
direction.
[0029] The flat tubes 30 have a plurality of through-holes 30a
serving as refrigerant flow passages as shown in FIG. 2. Heat
transfer tubes are not limited to flat tubes, and circular tubes
and tubes having any other shape can be used.
[0030] Of the pair of headers 10 and 20, the inlet header 10 on the
refrigerant inlet side of the plurality of flat tubes 30 is
connected to a refrigerant inlet pipe 10a, and the outlet header 20
on the refrigerant outlet side of the plurality of flat tubes 30 is
connected to a refrigerant outlet pipe 20a.
[0031] The present invention has a characteristic in, of the pair
of headers 10 and 20, particularly the header on the inlet side
(hereinafter referred to as inlet header 10). The structure thereof
will be described with reference to FIG. 3 below.
[0032] FIG. 3 is an exploded perspective view of the inlet header
10 of FIG. 1. FIG. 4 is a sectional view of the inlet header part
of FIG. 1 taken along line A-A.
[0033] The inlet header 10 has a box-like header main body 11 with
one side open, and a plate-like lid body 13 covering an opening 11a
of the header main body 11, and at least one chamber 10A serving as
a refrigerant flow passage is formed therebetween. In a bottom
surface 11b of the header main body 11 that faces the opening 11a,
a plurality of through-holes 12 serving as inlet side through-holes
are arranged side by side along the longitudinal direction of the
header main body 11. The refrigerant inlet side ends of the
plurality of flat tubes 30 are connected to the plurality of
through-holes 12, and communicate with the chamber 10A. The
refrigerant inlet pipe 10a is connected to the inlet header 10.
[0034] On a surface 13a of the lid body 13 that faces the
through-holes 12 in the at least one chamber 10A, a plurality of
grooves 14 extending in the longitudinal direction are formed over
the entire length in the lateral direction perpendicular to the
longitudinal direction. Specifically, the grooves 14 are formed by
the gaps between a plurality of protrusions 15 protruding from the
lid body 13. The grooves 14 are provided in order to draw
refrigerant liquid flowing into the inlet header 10 into the
grooves by the effect of surface tension and to thereby equally
distribute the refrigerant from the inlet header 10 to each
pass.
[0035] When manufacturing the inlet header 10 thus configured, the
box-like header main body 11 is formed by cutting or the like, and
the through-holes 12 are formed in the header main body 11. The lid
body 13 is formed by cutting or the like. The lid body 13 is
fittably configured so as to be able to be temporarily fastened to
the opening 11a of the header main body 11, and brazing filler
metal is applied to the fitting parts.
[0036] When manufacturing the whole heat exchanger 1, the lid body
13 is fitted in and temporarily fastened to the opening 11a of the
header main body 11, and, in a state where the outlet header 20,
the flat tubes 30, and the fins 40 are all assembled, the whole is
joined by brazing at the same time.
[0037] FIG. 5 is a diagram showing a refrigerant circuit of a
refrigeration cycle apparatus 50 to which the heat exchanger 1 of
FIG. 1 is applied.
[0038] The refrigeration cycle apparatus 50 includes a compressor
51, a condenser 52, an expansion valve 53 as a pressure reducing
device, and a evaporator 54. The heat exchanger 1 is used as at
least one of the condenser 52 and the evaporator 54. Gas
refrigerant discharged from the compressor 51 flows into the
condenser 52, exchanges heat with air passing through the condenser
52 to become high-pressure liquid refrigerant, and flows out. The
high-pressure liquid refrigerant flowing out of the condenser 52 is
reduced in pressure by the expansion valve 53 to become
low-pressure two-phase gas-liquid refrigerant, and flows into the
evaporator 54. The low-pressure two-phase gas-liquid refrigerant
flowing into the evaporator 54 exchanges heat with air passing
through the evaporator 54 to become low-pressure gas refrigerant,
and is sucked into the compressor 51 again.
[0039] FIG. 6 is a diagram showing the flow of refrigerant in the
case where the heat exchanger 1 of FIG. 1 is used as an
evaporator.
[0040] Two-phase gas-liquid refrigerant flowing out of the
expansion valve 53 flows through the refrigerant inlet pipe 10a
into the inlet header 10. The refrigerant flowing into the inlet
header 10 flows from one end to the other end of the flat tubes 30
constituting each pass of the heat exchanger 1, merges in the
outlet header 20, and flows through the refrigerant outlet pipe 20a
to the outside.
[0041] Next, the operation inside the inlet header will be
described. FIG. 7 is a diagram showing the flow state of
refrigerant in the inlet header 10. FIG. 8 is a sectional view
taken along line B-B of FIG. 7, and is a schematic diagram showing
a state where liquid refrigerant is accumulated between the grooves
in the inlet header 10. FIG. 9 includes diagrams (a) and (b)
showing the flow state of refrigerant in a header not provided with
grooves 14 as a comparative example.
[0042] First, the flow state of refrigerant in the comparative
example will be described with reference to FIG. 9. When the amount
of refrigerant circulating in the refrigerant circuit is large,
two-phase gas-liquid refrigerant flowing through the refrigerant
inlet pipe 10a into the inlet header 10 accumulates in the upper
part of the inlet header 10 owing to momentum at the time of inflow
as shown in FIG. 9 (a). In contrast, when the amount of refrigerant
circulating in the refrigerant circuit is small, two-phase
gas-liquid refrigerant flowing through the refrigerant inlet pipe
10a into the inlet header 10 accumulates in the lower part of the
inlet header 10 by the influence of gravity. As described above, in
the case of a configuration in which an inlet header 10 is not
provided with grooves 14, liquid refrigerant concentrates in the
upper part or the lower part, and distribution to each pass is
unequal.
[0043] Next, the flow state of refrigerant in the inlet header 10
of Embodiment 1 will be described with reference to FIG. 7 and FIG.
8. Two-phase gas-liquid refrigerant flowing through the refrigerant
inlet pipe 10a into the inlet header 10 flows in the inlet header
10, and liquid refrigerant is drawn into the grooves 14 by the
effect of surface tension. Thus, the liquid refrigerant is held
equally in the longitudinal direction in the inlet header 10, and
the amount of liquid refrigerant flowing into each flat tube 30 is
equalized.
[0044] As described above, according to Embodiment 1, by providing
the lid body 13 with a plurality of grooves 14 and causing surface
tension to act, unevenness of liquid refrigerant can be suppressed,
and refrigerant can be equally distributed to and caused to flow
into each of the plurality of flat tubes 30. Thus, the heat
exchange efficiency can be improved, and the capacity in the case
where the heat exchanger 1 is used as an evaporator can be exerted
to the maximum.
[0045] Since Embodiment 1 utilizes the action of surface tension of
liquid refrigerant to prevent uneven refrigerant distribution, the
pressure loss can be suppressed as compared to the conventional
configuration, and the performance degradation in the case where
the heat exchanger 1 is used as an evaporator can be
suppressed.
[0046] Since the inlet header 10 of Embodiment 1 is composed of a
header main body 11 and a lid body 13 having grooves 14, and has a
simple structure, it is easy to manufacture, and can be reduced in
cost.
[0047] The inlet header of the present invention is not limited to
the structure shown in FIG. 3, and various modifications, such as
the following (1) and (2), may be made without departing from of
the scope of the present invention.
(1) FIG. 10 is a Diagram Showing Modification 1 of the Grooves 14
of FIG. 3.
[0048] In the configuration of the grooves 14 of Embodiment 1 shown
in FIG. 5, the protrusions 15 are all the same in height. As shown
in FIG. 10, the height of the protrusions 15 may be alternately
large and small in the lateral direction of the lid body 13 (the
vertical direction in FIG. 10). In this case, the end faces
(inclined surfaces) of the grooves 14 closest to the flat tubes 30
(shown by dashed line 14a in FIG. 10) are wide as compared to the
configuration in which the protrusions 15 are all the same in
height as shown in FIG. 5. Therefore, it can be expected that the
effect of drawing liquid refrigerant is improved. The height of the
protrusions 15 is not limited to the configuration in which the
height of the protrusions 15 is alternately long and short. As long
as every two of the protrusions 15 adjacent in the lateral
direction of the lid body 13 differ in height, the same effects can
be expected. The following Modification 2 is another example of the
configuration in which every two of the protrusions 15 adjacent in
the lateral direction of the lid body 13 differ in height.
(2) FIG. 11 is a Diagram Showing Modification 2 of the Grooves 14
of FIG. 3.
[0049] The smaller the width (the length in the vertical direction
in FIG. 11) of the grooves 14 and the larger the height of the
grooves 14, the larger the refrigerant holding action in the
grooves 14 due to surface tension. Liquid refrigerant flowing into
the inlet header 10 tends to accumulate at both ends in the lateral
direction of the lid body 13. So, in Modification 2, the height of
the protrusions 15 increases from both ends toward the central part
in the lateral direction and the height of the grooves 14 is
adjusted so that the refrigerant holding force increases toward the
central part in the lateral direction. Thus, unevenness of
refrigerant is suppressed also in the lateral direction, and the
amount of refrigerant in each groove 14 can be equalized in both
the longitudinal direction and the lateral direction. As a result,
it can be expected that refrigerant can be more equally distributed
to each of the flat tubes 30. Although an example is shown here in
which only the height of the grooves 14 is varied, the width of the
grooves 14 may be decreased toward the central part.
[0050] As described above, the present invention is characterized
in that the inlet header 10 is provided with a plurality of grooves
14. As a heat exchanger 1 to which the character is applied, in
Embodiment 1, an example of a one-way flow passage type heat
exchanger is shown in which refrigerant flows from one side to the
other in the whole heat exchanger. The character can also be
applied to a U-turn flow passage type heat exchanger in which
refrigerant flows while making U-turns. The configuration in which
the present invention is applied to a U-turn flow passage type heat
exchanger will be described below with reference to the following
Embodiment 2 and Embodiment 3.
Embodiment 2
[0051] FIG. 12 is a diagram showing a heat exchanger 1A according
to Embodiment 2 of the present invention.
[0052] The heat exchanger 1A is a parallel flow heat exchanger in
which refrigerant is flowed in parallel, particularly a U-turn flow
passage type heat exchanger. Here, a configuration example is shown
in which the number of passes is five.
[0053] The heat exchanger 1A has a pair of headers 70 and 80 spaced
from each other, a plurality of (20 here) flat tubes (heat transfer
tubes) 30 that are disposed in parallel between the pair of headers
70 and 80 and both ends of which are connected to the pair of
headers 70 and 80, and a plurality of fins 40. The pair of headers
70 and 80, the flat tubes 30, and the fins 40 are all formed of
aluminum or aluminum alloy. The configurations of the flat tubes 30
and the fins 40 are the same as Embodiment 1.
[0054] FIG. 13 is an exploded perspective view of the header 70 of
FIG. 12. The header 70 has a box-like header main body 71 with one
side open. In a bottom surface 71b of the header main body 71 that
faces the opening 71a, a plurality of through-holes 72 to which a
plurality of flat tubes 30 are connected are arranged side by side
along the longitudinal direction of the header main body 71. Two
partition plates 73 are provided inside the header main body 71,
and three independent chambers A, B, and C that communicate with
the plurality of through-holes 72 and serve as refrigerant flow
passages are formed, and are covered by lid bodies 74A, 74B, and
74C, respectively.
[0055] The flow of refrigerant in the heat exchanger 1A will be
described later. A plurality of grooves 14 having the same function
as Embodiment 1 are formed in parts of the lid bodies 74A, 74B, and
74C that face the refrigerant inlet side ends of the flat tubes 30.
A specific description will be given below.
[0056] The chamber A is an inflow chamber into which refrigerant
from the outside flows. The refrigerant inlet side ends of the flat
tubes 30 are connected to the plurality of through-holes 72
communicating with the chamber A, and therefore grooves 14 are
formed on the whole of the lid body 74A. The chamber B is a U-turn
chamber serving as a U-turn flow passage. Of the plurality of
through-holes 72 communicating with the chamber B, the upper half
is connected to the refrigerant inlet side ends of the flat tubes
30, and the lower half is connected to the refrigerant outlet side
ends of the flat tubes 30, and therefore grooves 14 are formed on
the upper half of the lid body 74B. The chamber C is an outflow
chamber from which refrigerant flows to the outside. The plurality
of through-holes 72 communicating with the chamber C are connected
to the refrigerant outlet side ends of the flat tubes 30, and
therefore grooves 14 are not formed on the lid body 74C.
Hereinafter, of the plurality of through-holes 72, the
through-holes to which the refrigerant inlet side ends of the flat
tubes 30 are connected may be referred to as inlet side
through-holes, and the through-holes to which the refrigerant
outlet side ends of the flat tubes 30 are connected may be referred
to as outlet side through-holes.
[0057] On the other hand, the header 80 is provided with one
partition plate 83 as shown in FIG. 12, and the inside thereof is
divided into two chambers D and E. As with the header 70, the
chambers D and E are covered by lid bodies 84D and 84E,
respectively. Similarly to the above, a plurality of grooves 14 are
formed in parts of the lid bodies 84D and 84E that face the inlet
side through-holes of the flat tubes 30. Specifically, in each of
the lid bodies 84D and 84E, a plurality of grooves 14 are formed on
the upper half thereof.
[0058] When manufacturing the header 70 thus configured, the header
main body 71 is formed by cutting or the like, and the
through-holes 72 are formed in the header main body 71. The lid
bodies 74A, 74B, and 74C are formed by cutting or the like. The lid
bodies 74A, 74B, and 74C are fittably configured so as to be able
to be temporarily fastened to the openings of the chambers A, B,
and C of the header main body 71, and brazing filler metal is
applied to the fitting parts. The header 80 can be manufactured in
the same manner.
[0059] When manufacturing the whole heat exchanger 1B, the lid
bodies 74A, 74B, and 74C are fitted in and temporarily fastened to
the openings of the chambers A, B, and C, respectively, of the
header 70, and similarly, the lid bodies 84D and 84E are fitted in
and temporarily fastened to the openings of the chambers D and E,
respectively, of the header 80. In a state where the flat tubes 30
and the fins 40 are all assembled, the whole is joined by brazing
at the same time.
[0060] The flow of refrigerant in the heat exchanger 1A will be
described with reference to FIG. 12 below. Here, the flow of
refrigerant in the case where the heat exchanger 1A is used as an
evaporator. In FIG. 12, the solid arrows show the flow of
refrigerant.
[0061] Two-phase gas-liquid refrigerant flowing through the
refrigerant inlet pipe 10a flows into the chamber A, flows from one
end to the other end of a flat tube group connected to the chamber
A, and flows into the chamber D. The refrigerant flowing into the
chamber D makes a U-turn here, flows from one end to the other end
of another flat tube group connected to the chamber D, and flows
into the chamber B. The refrigerant flowing into the chamber B
makes a U-turn here, flows from one end to the other end of another
flat tube group connected to the chamber B, and flows into the
chamber E. The refrigerant flowing into the chamber E makes a
U-turn here, and flows from one end to the other end of another
flat tube group connected to the chamber E. The refrigerant flowing
out of this other end merges in the chamber C, and flows through
the refrigerant outlet pipe 20a to the outside.
[0062] In the above flow of refrigerant, since grooves 14 are
provided so as to face the refrigerant inlet side end of each flat
tube group, as in Embodiment 1, an uneven flow of refrigerant is
suppressed by the effect of surface tension of liquid refrigerant,
and refrigerant is substantially equally distributed from each
chamber to each pass.
[0063] As described above, according to Embodiment 2, also in a
U-turn flow passage type heat exchanger, the same advantageous
effects as Embodiment 1 can be obtained.
[0064] In Embodiment 2, in the plurality of protrusions 15 formed
on the lid bodies 74B, 84D, and 84E of the chambers B, D, and E
serving as U-turn chambers, the positions of the ends closest to
the border between the inlet side through-hole group and the outlet
side through-hole group are all the same. However, they may be as
shown in FIG. 14.
[0065] FIG. 14 shows modifications of the grooves 14 of FIG. 13 and
includes views of the lid body 74B, 84D, 84E as viewed from the
side of the surface on which grooves 14 are formed.
[0066] As shown in FIG. 14 (a), in the plurality of protrusions 15,
the positions of the ends closest to the border between the inlet
side through-hole group and the outlet side through-hole group may
be alternately staggered in the lateral direction of the lid body.
In this case, the end faces of the grooves 14 closest to the border
are inclined surfaces, the end faces are wide as compared to a
configuration in which the positions of the ends are all the same
as shown in FIG. 13, and therefore it can be expected that the
effect of drawing liquid refrigerant is improved. The positions of
the ends of the protrusions 15 are not limited to such an
alternately staggered configuration. As long as every two of the
protrusions 15 adjacent in the lateral direction of the lid body
differ in position, the same effect can be expected.
[0067] FIG. 14 (b) shows another example of the configuration in
which every two of the protrusions 15 adjacent in the lateral
direction of the lid body differ in position. As shown, the length
in the longitudinal direction of the protrusions 15 may decrease
toward the central part in the lateral direction, or, although not
shown, the length in the longitudinal direction of the protrusions
15 may increase toward the central part in the lateral
direction.
[0068] Modifications applied to the same component part as that of
Embodiment 1 are also applied to Embodiment 2. Modifications
described in Embodiment 2 may be combined with modifications
described in Embodiment 1. The same can be said also in Embodiment
3 described later.
Embodiment 3
[0069] Embodiment 3 corresponds to a configuration in which a
plurality of (two here) lines of U-turn flow passage type heat
exchangers of Embodiment 2 are provided in the air passage
direction.
[0070] FIG. 15 includes diagrams showing a heat exchanger according
to Embodiment 3 of the present invention. FIG. 15 (a) is a
schematic side view of the heat exchanger as viewed from a
direction perpendicular to the air passage direction shown by
dashed arrows. FIG. 15 (b) is a schematic sectional view of an
upstream side heat exchanging unit 1Ba on the upstream side in the
air passage direction. FIG. 15 (c) is a schematic sectional view of
a downstream side heat exchanging unit 1Bb on the downstream side
in the air passage direction. FIG. 15 (d) is a plan view of the
heat exchanger. Embodiment 3 will be described below focusing on
differences from Embodiment 2.
[0071] The heat exchanger 1B has a heat exchanger 1A that is the
same as Embodiment 2, as the upstream side heat exchanging unit
1Ba, and has the downstream side heat exchanging unit 1Bb on the
downstream side in the air passage direction. The upstream side
heat exchanging unit 1Ba and the downstream side heat exchanging
unit 1Bb are connected by an inter-line pipe 90.
[0072] Whereas the upstream side heat exchanging unit 1Ba has five
passes, the downstream side heat exchanging unit 1Bb has ten
passes. The downstream side heat exchanging unit 1Bb has more
passes than the upstream side heat exchanging unit 1Ba. The reason
that the number of passes differs between the upstream side heat
exchanging unit 1Ba and the downstream side heat exchanging unit
1Bb will be described later. The downstream side heat exchanging
unit 1Bb is the same as the upstream side heat exchanging unit 1Ba
except that it differs in the configuration of the header part from
the upstream side heat exchanging unit 1Ba.
[0073] A header 700 to which the inter-line pipe 90 is connected in
the downstream side heat exchanging unit 1Bb differs in the number
of partition plates from the upstream side heat exchanging unit
1Ba. The header 700 is provided with one partition plate 703, and
two chambers F and G are formed therein. A header 800 is provided
with no partition plate, and one chamber H is formed in the whole
thereof. As in Embodiments 1 and 2, grooves 14 are provided in
parts of the headers 700 and 800 of the downstream side heat
exchanging unit 1Bb that face the refrigerant inlet side end of
each flat tube 30.
[0074] The flow of refrigerant in the heat exchanger 1B will be
described with reference to FIG. 15 below. Here, the flow of
refrigerant in the case where the heat exchanger 1B is used as an
evaporator. In FIG. 15, the solid arrows show the flow of
refrigerant.
[0075] The flow of refrigerant in the upstream side heat exchanging
unit 1Ba of the heat exchanger 1B is the same as that in Embodiment
2. Refrigerant flowing out of the refrigerant outlet pipe 20a of
the upstream side heat exchanging unit 1B flows through the
inter-line pipe 90 and the refrigerant inlet pipe 100a into the
chamber F of the downstream side heat exchanging unit 1Bb. The
refrigerant flowing into the chamber F flows from one end to the
other end of a flat tube group communicating with the chamber F,
and flows into the chamber H. The refrigerant flowing into the
chamber H makes a U-turn here, flows from one end to the other end
of another flat tube group connected to the chamber H. The
refrigerant flowing out of this other end merges in the chamber G,
and flows through the refrigerant outlet pipe 200a to the
outside.
[0076] In the above flow of refrigerant, since grooves 14 are
provided so as to face the refrigerant inlet side end of each flat
tube group, as in Embodiments 1 and 2, an uneven flow of
refrigerant is suppressed by the effect of surface tension of
liquid refrigerant, and refrigerant is substantially equally
distributed from each chamber to each pass.
[0077] Next, the reason that the number of passes differs between
the upstream side heat exchanging unit 1Ba and the downstream side
heat exchanging unit 1Bb will be described.
[0078] When the heat exchanger 1B is used as an evaporator,
refrigerant inflows in a two-phase gas-liquid state, and finally
outflows in a state of gas refrigerant. Therefore, the quality
increases as refrigerant flows toward the second half of the flow
passage. When the quality is low, the pressure loss during passing
through the flow passage is small, and therefore it is preferable
to increase the flow rate of refrigerant to increase the heat
transfer coefficient. On the other hand, when the quality is high,
the pressure loss during passing through the flow passage is large,
and therefore it is preferable to decrease the flow rate of
refrigerant. The larger the number of passes, the lower the flow
rate of refrigerant.
[0079] In the upstream side heat exchanging unit 1Ba corresponding
to the first half of the flow passage in the heat exchanger 1B, the
quality of refrigerant is low. Therefore, the number of passes is
reduced to increase the flow rate of refrigerant, and to increase
the heat transfer coefficient. On the other hand, in the downstream
side heat exchanging unit 1Bb corresponding to the second half of
the flow passage, the quality is high. Therefore, the number of
passes is increased to reduce the flow rate of refrigerant, and to
reduce the pressure loss.
[0080] As described above, according to Embodiment 3, the same
advantageous effects as Embodiment 1 and 2 can be obtained, and
owing to the multi-line configuration, the heat exchange capacity
can be improved. Since the number of passes on the upstream side in
the air passage direction where the quality of passing refrigerant
is low is reduced to increase the flow rate of refrigerant, and to
increase the heat transfer coefficient, the heat exchange capacity
can also be improved thereby.
[0081] Although a two-line configuration is described in Embodiment
3, a three or more-line configuration may be used.
[0082] Although, in Embodiments 1 to 3, examples are shown in which
the outer shape of header is square, the outer shape of header is
not limited to a square shape, and may be a cylindrical shape. In
the case of a multi-line configuration as in Embodiment 3, a square
shape is preferable in terms of securing the size required as a
header and causing lines to interfere with each other.
* * * * *