U.S. patent application number 11/418611 was filed with the patent office on 2006-11-16 for intermediate cooler for air-conditioning refrigerant.
Invention is credited to Hubertus Rudolf Kamsma.
Application Number | 20060254757 11/418611 |
Document ID | / |
Family ID | 36889203 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060254757 |
Kind Code |
A1 |
Kamsma; Hubertus Rudolf |
November 16, 2006 |
Intermediate cooler for air-conditioning refrigerant
Abstract
An intermediate heat exchanger for refrigerant which passes
through a high pressure side and a low pressure side in which the
refrigerant has a different temperature circulating in an air
conditioning loop. The heat exchanger includes a thin
pressure-stable vessel defining at least one longitudinal
compartment therein, and a flat multi-chamber tube through which
refrigerant on one side flows. The tube extends through the at
least one compartment and is spaced from at least two opposing
walls of the compartment. Heat exchange ribs roughly fill the
compartment between the tube and the two opposing walls, wherein
refrigerant on the other side flows through the compartment between
the tube and the two opposing walls.
Inventors: |
Kamsma; Hubertus Rudolf;
(Filderstadt, DE) |
Correspondence
Address: |
WOOD, PHILLIPS, KATZ, CLARK & MORTIMER
500 W. MADISON STREET
SUITE 3800
CHICAGO
IL
60661
US
|
Family ID: |
36889203 |
Appl. No.: |
11/418611 |
Filed: |
May 5, 2006 |
Current U.S.
Class: |
165/163 ;
165/157; 165/183 |
Current CPC
Class: |
F28D 7/106 20130101;
F28D 7/1692 20130101; F25B 2500/18 20130101; F28F 1/126 20130101;
F25B 40/00 20130101; F28F 2255/16 20130101; F28F 1/022 20130101;
F25B 9/008 20130101; F25B 2309/061 20130101; F28F 2009/224
20130101; F28F 9/005 20130101 |
Class at
Publication: |
165/163 ;
165/157; 165/183 |
International
Class: |
F28D 7/02 20060101
F28D007/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 10, 2005 |
DE |
DE 102005021464.9 |
Claims
1. An intermediate heat exchanger for refrigerant which passes 2
through a high pressure side and a low pressure side in which the
refrigerant has a different temperature circulating in an air
conditioning loop, comprising: a thin pressure-stable vessel
defining at least one longitudinal compartment therein; a flat
multi-chamber tube through which refrigerant on one side flows,
said tube extending through said at least one compartment and
spaced from at least two opposing walls of said compartment; heat
exchange ribs roughly filling the compartment between the tube and
said two opposing walls, wherein refrigerant on the other side
flows through the compartment between the tube and the two opposing
walls.
2. The heat exchanger of claim 1, wherein at least one of the
opposing walls is curved, and said ribs fill the compartment
between said curved wall and said flat multi-chamber tube.
3. The heat exchanger of claim 1, further comprising at least one
longitudinal wall dividing the vessel into at least two
compartments, wherein the multi-chamber tube extends in the
longitudinal direction of said compartments and is substantially
straight through at least one compartment.
4. The heat exchanger of claim 3, wherein said flat multi-chamber
tube has a U-bend between two parallel straight portions, wherein
said straight portions separately extend through two parallel
compartments separated by said at least one longitudinal wall.
5. The heat exchanger of claim 1, wherein said heat exchange ribs
are arranged so as to be exposed to essentially no pressure
loads.
6. The heat exchanger of claim 1, wherein said vessel is
substantially cylindrical with closing covers at each end of the
cylinder.
7. The heat exchanger of claim 1, further comprising a plurality of
longitudinal walls dividing said vessel into a plurality of
parallel longitudinal compartments.
8. The heat exchanger of claim 7, wherein a flat multi-chamber tube
extends through each vessel compartment, with said tubes being
arranged in series with one tube configured to input or output the
refrigerant, and at least one other tube configured to output or
input, respectively, the refrigerant.
9. The heat exchanger of claim 8, wherein said one tube has a
greater cross-section than the other tubes.
10. The heat exchanger of claim 9, wherein said vessel is
substantially cylindrical, and said one tube extends substantially
along the center plane of the cylindrical vessel.
11. The heat exchanger of claim 1, wherein said vessel is
substantially cylindrical, and the cross-sectional shape of the
compartments is generally rectangular.
12. The heat exchanger of claim 1, wherein the chambers in the flat
multi-chamber tube have a diameter of about 1.20 mm or less.
13. The heat exchanger of claim 1, wherein the length to diameter
ratio (L/D) of the vessel is at least 3:1.
14. The heat exchanger of claim 1, wherein both the vessel and the
multi-chamber tube are extruded.
15. The heat exchanger of claim 1, wherein said ribs have walls
extending longitudinally through said compartment.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO A MICROFICHE APPENDIX
[0003] Not applicable.
TECHNICAL FIELD
[0004] The present invention relates to heat exchangers, and more
particularly toward intermediate cooling of refrigerant circulating
in an air-conditioning loop.
BACKGROUND OF THE INVENTION
AND
TECHNICAL PROBLEMS POSED BY THE PRIOR ART
[0005] Air-conditioning loops commonly include a refrigerant
flowing through a compressor, gas cooler, evaporator (heat
exchanger) and expansion valve, where the refrigerant passes
through a high pressure side and a low pressure side in which the
refrigerant has a different temperature.
[0006] One heat exchanger for exchanging heat between the high and
low pressure sides, often referred to as an internal heat exchanger
in transcritical air conditioning loops, is known from DE 196 35
454 A1 which provides improved heat exchange rates. However,
manufacture of this device (arranged flat in the incorporation
space in the vehicle) appears to be fairly demanding, among other
things because the flat multi-chamber tubes are deformed as coils
and insertion of the heat-conducting ribs between the windings of
the coils is also complicated.
[0007] An intermediate heat exchanger is also disclosed in DE 103
22 028 B4, which is integrated as a coaxial tube in the collecting
tube of the evaporator. This is a compact configuration which
provides some ease of manufacture.
[0008] Another device for the same area of application is disclosed
in U.S. Pat. No. 6,681,597 B1, in which the high pressure side and
low pressure side flow through extruded, flat multi-chamber tubes
which extend into a collection reservoir with their broad flat
sides in conductive heat exchange relationship.
[0009] The present invention is directed toward improving upon the
prior art to provide an easy to manufacture, compact heat exchanger
for high and low pressure sides of an air-conditioning loop which
provides efficient heat exchange.
SUMMARY OF THE INVENTION
[0010] In one aspect of the present invention, an intermediate heat
exchanger is provided for refrigerant which passes through a high
pressure side and a low pressure side in which the refrigerant has
a different temperature circulating in an air conditioning loop.
The heat exchanger includes a thin pressure-stable vessel defining
at least one longitudinal compartment therein, and a flat
multi-chamber tube through which refrigerant on one side flows. The
tube extends through the at least one compartment and is spaced
from at least two opposing walls of the compartment. Heat exchange
ribs roughly fill the compartment between the tube and the two
opposing walls, wherein refrigerant on the other side flows through
the compartment between the tube and the two opposing walls.
[0011] In one form of this aspect of the present invention, at
least one of the opposing walls is curved, and the ribs fill the
compartment between the curved wall and the flat multi-chamber
tube.
[0012] In another form of this aspect of the present invention, at
least one longitudinal wall divides the vessel into at least two
compartments, wherein the. multi-chamber tube extends in the
longitudinal direction of the compartments and is substantially
straight through at least one compartment. In a further form, the
flat multi-chamber tube has a U-bend between two parallel straight
portions, wherein the straight portions separately extend through
two parallel compartments separated by the at least one
longitudinal wall.
[0013] In still another form of this aspect of the present
invention, the heat exchange ribs are arranged so as to be exposed
to essentially no pressure loads.
[0014] In yet another form of this aspect of the present invention,
the vessel is substantially cylindrical with closing covers at each
end of the cylinder.
[0015] In another form of this aspect of the present invention, a
plurality of longitudinal walls divide the vessel into a plurality
of parallel longitudinal compartments. In a further form, a flat
multi-chamber tube extends through each vessel compartment, with
the tubes being arranged in series with one tube configured to
input or output the refrigerant, and at least one other tube
configured to output or input, respectively, the refrigerant. In a
still further form, the one tube has a greater cross-section than
the other tubes. In yet a further form, the vessel is substantially
cylindrical, and the one tube extends substantially along the
center plane of the cylindrical vessel.
[0016] In still another form of this aspect of the present
invention, the vessel is substantially cylindrical, and the
cross-sectional shape of the compartments is generally
rectangular.
[0017] In yet another form of this aspect of the present invention,
the chambers in the flat multi-chamber tube have a diameter of
about 1.20 mm or less.
[0018] In another form of this aspect of the present invention, the
length to diameter ratio (L/D) of the vessel is at least 3:1.
[0019] In still another form of this aspect of the present
invention, both the vessel and the multi-chamber tube are
extruded.
[0020] In yet another form of this aspect of the present invention,
the ribs have walls extending longitudinally through the
compartment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a longitudinal cross-section through a first
embodiment of an intermediate heat exchanger incorporating the
present invention;
[0022] FIG. 2 is an axial cross-section through heat exchanger of
FIG. 1;
[0023] FIG. 3 is a perspective view of one end of the heat
exchanger of FIG. 1 showing inlets and outlets for the
refrigerant;
[0024] FIG. 4 is an axial cross-section through a second embodiment
of a heat exchanger incorporating the present invention;
[0025] FIG. 5 is a longitudinal schematic view of a third
embodiment of a heat exchanger incorporating the present
invention;
[0026] FIG. 6 is an axial cross-section through a fourth embodiment
of a heat exchanger incorporating the present invention;
[0027] FIG. 7 is an axial cross-section through a fifth embodiment
of a heat exchanger incorporating the present invention;
[0028] FIG. 8 is an axial cross-section through a sixth embodiment
of a heat exchanger incorporating the present invention; and
[0029] FIG. 9 is an axial cross-section through a seventh
embodiment of a heat exchanger incorporating the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] As illustrated in FIGS. 1 and 2, in accordance with one
embodiment of the invention, a vessel 20 is formed as a round tube
produced by extrusion. The tube has two longitudinal walls 22 and
24, which divide the tube into three compartments 26, 28, 30, each
of which include a flat extruded multi-chamber tube 34 extending
roughly the entire length of the compartments (the multi-chamber
tube 34 could also be a soldered or welded tube with an internal
insert forming the chambers).
[0031] In the illustrated embodiment, each multi-chamber tube 34
has two rows of passages 36 having a diameter of about 1.20 mm or
less.
[0032] Further, each multi-chamber tube 34 is provided with one or
more heat-conducting ribs 40 that fills up the cross-section of the
corresponding compartmet, preferably as fully as possible, so that
the refrigerant flowing there does not flow through large, free
cross-sectional spaces and therefore heat exchange with the tubes
34 is enhanced.
[0033] In the FIGS. 1-2 embodiment, the refrigerant on the high
pressure side (arrows in FIG. 1) flows on the top through the
middle connection opening into the flat and larger multi-chamber
tube 34 (in the center of the vessel 20). The refrigerant then
flows downward through that tube, and at the vessel bottom is
distributed to the two other smaller multi-chamber tubes 34,
through which the refrigerant flows back up. From the two smaller
tubes 34, the refrigerant flows via two outflow openings to an
expansion device (not shown), and then, for example, through an
evaporator.
[0034] In the FIGS. 1-2 embodiment, the refrigerant on the low
pressure side flows into a corresponding inflow opening 44 either
into the middle compartment 28 (in which case it flows downward
through the heat exchange ribs 40 in the middle compartment 28 and
then is distributed to the two other compartments to flow up
through them), or the refrigerant on the low pressure side is
distributed from the inflow opening 44 to all three compartments
26, 28, 30 (in which case it flows downward through all three
compartments 26, 28, 30 and then to the compressor [not shown] in
the loop).
[0035] The tube on the top and bottom has appropriate covers 48,
which complete the vessel 20. As is apparent, flow channels for the
refrigerant on the high pressure side are formed in cover 48.
[0036] The above described components may advantageously be made of
aluminum, which parts may be assembled and joined by soldering.
[0037] FIG. 3 shows inflow and outflow of the refrigerant on the
high pressure side and low pressure side one embodiment such as
described in connection with FIGS. 1-2 above. Reference numbers 44,
50, 52 show flow passages of the refrigerant on the low pressure
side, with this low pressure refrigerant flowing at 44 into the
middle compartment 28 (or flowing out of this compartment there). A
connection block 54 includes channels and may be soldered with the
other mentioned components, and includes two additional inflow (or
outflow) openings or channels 50, 52 that communicate with the
other two compartments 28, 30. Openings or channels 60, 62, 64, 66,
68 are also provided for the refrigerant on the high pressure side,
such openings being formed in the upper cover 48 and communicate
with the multi-chamber tubes 34.
[0038] FIG. 4 illustrates another practical example in which only
the middle compartment 28 is occupied by the multi-chamber tube 34
and heat exchange ribs 40. Refrigerant on the low pressure side
flows through the ribs 40 in the middle compartment 28, and may (or
may not) also flow in the two other compartments 26, 30. (It should
be recognized that the longitudinal walls 70 can be made
significantly thinner than is illustrated by FIG. 4, since roughly
the same pressure is present in the compartments 26, 28, 30).
[0039] FIG. 5 schematically shows another embodiment incorporating
the present invention, wherein the vessel 20 may have with a
somewhat smaller degree of thinness. The multi-chamber tube 34 in
this embodiment has a U-shaped bend 74, whereby inflow and outflow
of the refrigerant may both occur on the upper cover 48 (where the
reference HP stands for the high pressure side and LP for the low
pressure side). The lower cover 48A is arched and the longitudinal
wall 22 ends so that the refrigerant on the low pressure side can
flow from compartment 26 back to the other compartment 28, with the
remaining cross-section of both compartments 26, 28 being filled by
heat exchange ribs 40 such as previously described.
[0040] FIGS. 6 and 7 show embodiments which facilitate insertion of
the heat exchange ribs 40 with the multi-chamber tube 34 into the
corresponding compartments, where the cross-section of compartments
26 and 30 in vessel 20 is configured with an appropriate shape. In
the FIG. 6 embodiment, the wall thickness of the vessel 20 is
partially increased somewhat at reference number 78, whereas, in
FIG. 7, recesses 80 are included in the wall of vessel 20. Such
embodiments are easy to produce by extrusion. Further, ordinary
corrugated ribs can be used as heat exchange ribs 40, which are
wound coil-like around the corresponding multi-chamber tube 34 and
then inserted together with the tube into the appropriate
compartment 26, 28, 30X.
[0041] Perhaps the simplest form of the present invention is shown
in FIG. 8, wherein the multi-chamber tube 34 extends linearly
through the vessel 20 along its center longitudinal plane. The
semicircular cross-sections of the compartments 26 of vessel 20
created by the multi-chamber tube 34 are filled up with
heat-conducting ribs 40 which have a rib height adapted to the
round shape of vessel 20.
[0042] FIG. 9 illustrates yet another embodiment of an intermediate
heat exchanger incorporating the present invention, which
embodiment is particularly suitable for manufacture. In this
embodiment, two longitudinal walls 22A, 24A include bent
longitudinal edges 84, preferably having some elasticity, which lie
against the inside of the vessel wall. The multi-chamber tube 34,
the heat-conducting ribs 40 and the two longitudinal walls 22A, 24A
may be advantageously combined into a stack and pushed together
into the vessel 20 so that the longitudinal edges 84 abut the
vessel wall, whereby perfect solder connections are made possible
or supported. Moreover, the compartment 28 is filled up by
heat-conducting ribs 40 that have a uniform rib height and are
therefore favorable to manufacture.
[0043] Overall, the suitability for manufacture of intermediate
heat exchangers incorporating the present invention can be
understood from the description and the drawings. Further, it
should be appreciated that the efficiency of heat exchange, and the
ability to fit into limited space requirements, are further of heat
exchangers according to the present invention because of a very
thin configuration of the vessel 20. The thinness of the vessel 20,
expressed by the length L/diameter D ratio (see FIG. 1), may be
advantageously at least 3:1, although an L/D ration of 6:1 or even
thinner is preferred.
[0044] Since the vessel 20 over its entire length is designed as a
heat exchanger, good results in terms of heat exchange efficiency
can be achieved. The vessel 20 and the intermediate heat exchanger
have a noticeably slim appearance and are therefore particularly
suitable for applications in which narrow spaces are present
(according to the present invention, vessels with a length/diameter
ratio of at least 3:1 or larger are considered slim vessels).
Further, since the multi-chamber tubes 34 extend essentially
straight through the compartments 26, 28, 30 (i.e., it need not be
deformed), they may be readily assembled in the compartments
together with the heat exchange ribs 40 almost completely filling
up the remaining compartment cross-section, thereby providing both
easy assembly and good heat exchange efficiency.
[0045] It should also be appreciated that the round shape of the
longitudinal wall of the vessel 20 is able to withstand enormously
high pressures, and therefore the heat exchange ribs 40 can be made
from a very thin sheet material since it is not exposed to
significant pressure stresses.
[0046] In addition, it should also be appreciated that the
extrusion process for production of the vessel 20 makes it possible
to design cross-section of the internal compartments 26, 28, 30 in
the otherwise preferably round pressure vessel 20 to be
rectangular, and as a result the heat exchange ribs 40 can be very
favorably inserted there without significant squeezing and in so
doing almost completely fill up the compartment as mentioned.
Roughly rectangular or square compartment cross-sections can be
advantageously achieved either by partially increasing the wall
thickness of the vessel 20 or by including gradations of the
otherwise round vessel in the longitudinal direction of the vessel
20, both of which can be efficiently manufactured by the
deformation method of extrusion.
[0047] Still other aspects, objects, and advantages of the present
invention can be obtained from a study of the specification, the
drawings, and the appended claims. It should be understood,
however, that the present invention could be used in alternate
forms where less than all of the objects and advantages of the
present invention and preferred embodiment as described above would
be obtained.
* * * * *