U.S. patent application number 13/884819 was filed with the patent office on 2013-11-07 for plate-type heat exchanger and air-conditioning circuit for a vehicle.
This patent application is currently assigned to Valeo Klimasysteme GMBH. The applicant listed for this patent is Roland Haussmann, Jens Meister, Reinhard Urban. Invention is credited to Roland Haussmann, Jens Meister, Reinhard Urban.
Application Number | 20130292090 13/884819 |
Document ID | / |
Family ID | 44913295 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130292090 |
Kind Code |
A1 |
Haussmann; Roland ; et
al. |
November 7, 2013 |
Plate-Type Heat Exchanger And Air-Conditioning Circuit For A
Vehicle
Abstract
A plate-type heat exchanger (30) for a vehicle cools a cooling
fluid by means of a coolant. The exchanger (30) has a plurality of
heat exchanger plates (40) which are stacked one on top of the
other. Coolant chambers (44) and cooling fluid chambers (46), which
each have an inflow (48, 52) and an outflow (50, 54) for the
coolant and/or the cooling fluid are formed between adjacent heat
exchanger plates (40). The coolant and/or cooling fluid chambers
(44, 46) are embodied in their entirety as U-shaped flow ducts (64,
68), wherein the assigned inflow (48, 52) is arranged at the end of
a first limb, and the assigned outflow(50, 54) is arranged at the
end of a second limb, of the flow ducts (64, 68). The invention
also relates to an air-conditioning circuit (10) for a vehicle.
Inventors: |
Haussmann; Roland;
(Wiesloch, DE) ; Meister; Jens; (Erftstadt,
DE) ; Urban; Reinhard; (Dietzhausen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Haussmann; Roland
Meister; Jens
Urban; Reinhard |
Wiesloch
Erftstadt
Dietzhausen |
|
DE
DE
DE |
|
|
Assignee: |
Valeo Klimasysteme GMBH
Bad Rodach
DE
|
Family ID: |
44913295 |
Appl. No.: |
13/884819 |
Filed: |
November 9, 2011 |
PCT Filed: |
November 9, 2011 |
PCT NO: |
PCT/EP11/69712 |
371 Date: |
July 18, 2013 |
Current U.S.
Class: |
165/96 ;
165/166 |
Current CPC
Class: |
F28F 9/027 20130101;
F28F 3/08 20130101; F28D 9/005 20130101 |
Class at
Publication: |
165/96 ;
165/166 |
International
Class: |
F28F 3/08 20060101
F28F003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2010 |
DE |
DE 102010050894.2 |
Claims
1. A plate-type heat exchanger (30) for a vehicle for cooling a
cooling fluid by means of a coolant, the heat exchanger (30) having
a plurality of heat exchanger plates (40) which are stacked one on
top of each other, wherein coolant chambers (44) and cooling fluid
chambers (46), which each have an inflow (48, 52) and an outflow
(50, 54) for the coolant and/or the cooling fluid, are formed
between adjacent heat exchanger plates (40), and the coolant and/or
cooling fluid chambers (44, 46) are embodied altogether as U-shaped
flow ducts (64, 68), wherein the assigned inflow (48, 52) is
arranged at the end of a first limb, and the assigned outflow (50,
54) is arranged at the end of a second limb, of the U-shaped flow
duct.
2. A plate-type heat exchanger (30) according to claim 1, wherein
the heat-exchanger plates (40) have, in the plane of their plates,
both a main extent direction (58) and a secondary extent direction
(60) running perpendicular thereto, and are arranged one next to
the other in a stacking direction (42) which runs perpendicular to
the main extent direction (58) and to the secondary extent
direction (60), and wherein the inflow (48) and outflow (50) for
the coolant are provided in the main extent direction (58), at the
same end of the heat exchanger plates (40).
3. A plate-type heat exchanger (30) according to claim 2,
comprising a common inflow connection (49) and outflow connection
(51) for all the coolant chambers (44), wherein a connection
component (62) is provided which permits direct attachment of an
expansion valve (28) for the coolant to the plate-type heat
exchanger (30).
4. A plate-type heat exchanger (30) according to claim 3, wherein
the connection component (62) has a coolant distributor (81) which
homogenizes distribution of the coolant phase mixture among
different coolant chambers (44) of the plate-type heat exchanger
(30).
5. A plate-type heat exchanger (30) according to claim 1, wherein
the heat exchanger plates (40) have, in the plane of their plates,
both a main extent direction (58) and a secondary extent direction
(60) running perpendicular thereto, and are arranged one next to
the other in a stacking direction (42) which runs perpendicular to
the main extent direction (58) and to the secondary extent
direction (60), and wherein the inflow (52) and outflow (52) (54)
for the cooling fluid are provided in the main extent direction
(58), at the same end or at opposite ends of the heat exchanger
plates (40).
6. A plate-type heat exchanger (30) according to claim 1,
comprising in each case a one common inflow connection (49) and a
common outflow connection (51) for all the coolant chambers (44),
and in each case a common inflow connection (53) and a common
outflow connection (55) for all the cooling fluid chambers (46),
wherein the common inflow connection (49) and outflow connection
(51) for the coolant are arranged in the stacking direction (42) on
the same lateral surface or on opposite lateral surfaces of the
plate-type heat exchanger (30), as are the inflow connection (53)
and outflow connection (55) for the cooling fluid.
7. A plate-type heat exchanger (30) according to claim 1,
comprising a common inflow connection (53) and/or outflow
connection (55) for all the cooling fluid chambers (46), wherein an
end plate (56) is provided which is arranged in front of or behind
the heat exchanger plates (40) in the stacking direction (42) and
which forms at least one flow duct for the cooling fluid, the at
least one flow duct connects the common inflow connection (53)
and/or outflow connection (55) of the heat exchanger plates (40) to
a connection (72) for a cooling fluid system.
8. A plate-type heat exchanger (30) according to claim 1, wherein
the heat exchanger plates (40) have, in the plane of their plates,
both a main extent direction (58) and a secondary extent direction
(60) running perpendicular thereto, and are arranged one next to
the other in a stacking direction (42) which runs perpendicular to
the main extent direction (58) and to the secondary extent
direction (60), and in that the inflow (48) and outflow (50) for
the coolant are arranged in the main extent direction (58), at
opposite ends of the heat exchanger plates (40), as are the inflow
(52) and outflow (54) for the cooling fluid.
9. A plate-type heat exchanger (30) according to claim 8, wherein
the directions of flow in adjoining coolant chambers (44) and
cooling fluid chambers (46) are the same or opposed.
10. A plate-type heat exchanger (30) according to claim 1, wherein
the heat exchanger plates (40) form a flow duct (70) in the cooling
fluid chambers (46), and the flow duct (70) runs from an inflow
(52) of the cooling fluid at one end of the heat exchanger plates
(40) in the main extent direction (58) to an outflow (54) of the
cooling fluid at the opposite end of the heat exchanger plates
(40).
11. A plate-type heat exchanger (30) according to claim 1, wherein
the difference of pressure across the first limb of the U-shaped
flow duct (64) for the coolant is between 70% and 100% of the
overall difference of pressure, and the difference of pressure
across the second limb of the U-shaped flow duct (64) for the
coolant in the direction of flow is between 0% and 30% of the
overall difference of pressure.
12. A plate-type heat exchanger (30) according to claim 1, wherein
the U-shape of the flow ducts (64, 68) is formed by an intermediate
wall (66) which is formed by a part (74), which connects the
adjacent heat exchanger plates (40), or by a shaped section (76) of
at least one heat exchanger plate (40).
13. A plate-type heat exchanger (30) according to claim 1, wherein
the limbs of the U-shaped flow ducts (64, 68) are formed by
numerous elongated ducts arranged one next to the other.
14. An air-conditioning circuit (10) for a vehicle, the
air-conditioning circuit (10) having a primary circuit (12) for a
coolant and a secondary circuit (14) for a cooling fluid, wherein
the primary circuit (12) and the secondary circuit (14) are coupled
via the plate-type heat exchanger (30) according to claim 1.
Description
[0001] The invention relates to a plate-type heat exchanger for a
vehicle for cooling a cooling fluid by means of a coolant, having a
plurality of heat exchanger plates which are stacked one on top of
the other, and an air-conditioning circuit for a vehicle, in
particular for a vehicle having an electric motor.
[0002] Plate-type heat exchangers of the type specified at the
beginning are known in which the cooling fluid or the coolant flows
through the intermediate spaces between adjacent plates, wherein
the cooling fluid flows from a first side of the plate-type heat
exchanger to the opposite second side of the plate-type heat
exchanger, while the coolant flows in the opposite direction from
the second end to the first end of the plate-type heat exchanger.
The length of the flow ducts in the plate-type heat exchanger
corresponds here essentially to the length of the plate-type heat
exchanger from the first end to the second end. The outer
dimensions of the plate-type heat exchanger and the position of the
connections of the plate-type heat exchanger are therefore
dependent on the desired length of the flow ducts in the plate-type
heat exchanger.
[0003] The object of the invention is to provide a plate-type heat
exchanger with a compact design as well as an air-conditioning
circuit for a vehicle, which air-conditioning circuit can be
embodied in a compact fashion which is optimized for the
installation space.
[0004] The object of the invention is achieved by means of a
plate-type heat exchanger for a vehicle for cooling a cooling fluid
by means of a coolant, having a plurality of heat exchanger plates
which are stacked one on top of the other, wherein coolant chambers
and cooling fluid chambers, which each have an inflow and an
outflow for the coolant and/or the cooling fluid, are formed
between adjacent heat exchanger plates. The coolant and/or cooling
fluid chambers are embodied in their entirety as U-shaped flow
ducts, wherein the assigned inflow is arranged at the end of the
first limb, and the assigned outflow is arranged at the end of the
second limb, of the U-shaped flow duct. The U-shaped flow ducts
make it possible to double the length of the flow duct of the
coolant chambers and/or cooling fluid chambers without increasing
the length of the plate-type heat exchanger, and to position the
connections for the inflow and outflow of the coolant and/or of the
cooling fluid in a flexible way.
[0005] The heat exchanger plates preferably have, in the plane of
their plates, both a main extent direction and a secondary extent
direction running perpendicular thereto, and are arranged one next
to the other in a stacking direction which runs perpendicular to
the main extent direction and to the secondary extent direction
(referred to below as "definition of direction").
[0006] With this predefined definition of direction it is
advantageous that the inflow and outflow for the coolant are
provided in the main extent direction, at the same end of the heat
exchanger plates. In this way, the inflow and outflow for the
coolant can be positioned near to one another without having to
shorten the length of the flow duct for the coolant.
[0007] The heat exchanger plates can be substantially rectangular
and the main extent direction can then run in the longitudinal
direction of the plates.
[0008] A common inflow connection and outflow connection for all
the coolant chambers is provided with a connection component which
permits direct attachment of an expansion valve for the coolant to
the plate-type heat exchanger. In this way it is possible to
eliminate the need for a line system between the expansion valve
and the plate-type heat exchanger.
[0009] In order to achieve a uniform cooling performance in all of
the coolant chambers, the connection component can have a coolant
distributor which homogenizes distribution of the coolant phase
mixture among the various coolant chambers of the plate-type heat
exchanger.
[0010] In the above-mentioned definition of direction, the inflow
and outflow for the cooling fluid are provided at the same or at
opposite ends of the heat exchanger plates in the main extent
direction. This permits a variable arrangement of the connections
for the cooling fluid.
[0011] For a flexible arrangement of the connections of the
plate-type heat exchanger on a primary circuit and secondary
circuit, in each case a common inflow connection and a common
outflow connection can be provided for all the coolant chambers and
in each case a common inflow connection and a common outflow
connection can be provided for all the cooling fluid chambers,
wherein the common inflow connection and outflow connection for the
coolant are arranged in the stacking direction on the same lateral
surface or on opposite lateral surfaces of the plate-type heat
exchanger, as are the inflow connection and outflow connection for
the cooling fluid.
[0012] An end plate can be provided on a common inflow connection
and/or outflow connection for all the cooling fluid chambers, which
end plate is arranged in front or behind the heat exchanger plates
in the stacking direction and forms at least one flow duct for the
cooling fluid, which flow duct connects the common inflow
connection and/or outflow connection of the heat exchanger plates
to a connection for a cooling fluid system. In this way, the end
plate of the plate-type heat exchanger forms a type of adaptor
which permits a compact and advantageously arranged connection to
the cooling fluid system.
[0013] In the above-mentioned definition of direction, a further
embodiment provides for the inflow and outflow for the coolant to
be arranged in the main extent direction, at opposite ends of the
heat exchanger plates, in the same way as the inflow and outflow
for the cooling fluid. Given a corresponding orientation of the
plate-type heat exchanger, this arrangement of the connections
permits a connection for cooling fluid at the upper end of the heat
exchanger plates and a connection for coolant at the lower end of
the heat exchanger plates. This therefore easily permits, on the
one hand, degassing of the cooling fluid chambers and, on the other
hand, a return flow of oil in the coolant chambers.
[0014] The directions of flow in adjoining coolant chambers and
cooling fluid chambers can be the same or opposite. The
transmission of heat between the coolant and the cooling fluid
along the flow duct can be optimized by the selection of the
direction of flow of the coolant and cooling fluid.
[0015] According to a further embodiment, the heat exchanger plates
can form a flow duct in the cooling fluid chambers, which flow
ducts runs from an inflow of the cooling fluid at one end of the
heat exchanger plates in the main extent direction to an outflow of
the cooling fluid at the opposite end of the heat exchanger
plates.
[0016] In order to improve the overall effectiveness of the
exchange of heat between the cooling fluid and the coolant, the
difference in pressure across the first limb of the U-shaped flow
duct for the coolant is between 70% and 100%, preferably between
80% and 92% of the overall difference in pressure, and the
difference in pressure across the second limb of the U-shaped flow
duct for the coolant in the direction of flow is between 0% and
30%, preferably between 8% and 20% of the overall difference in
pressure.
[0017] The U shape of the flow ducts is preferably formed by an
intermediate wall which is provided by a part, which connects the
adjacent heat exchanger plates, or by a shaped section of at least
one heat exchanger plate. This permits a simple design of the
plate-type heat exchanger.
[0018] In order to homogenize the distribution of the coolant or
the cooling fluid in the U-shaped flow ducts, the limbs of the
U-shaped flow ducts can be formed by numerous elongated ducts
arranged one next to the other.
[0019] The invention also relates to an air-conditioning circuit
for a vehicle, in particular for a vehicle having an electric
motor, with a primary circuit for a coolant and a secondary circuit
for a cooling fluid, wherein the primary circuit and the secondary
circuit are coupled to the plate-type heat exchanger according to
the invention. Since the plate-type heat exchanger itself is of
compact design and has a flexible arrangement of the connections
for the coolant and cooling fluid, a compact design which can be
implemented in a flexible way is made possible for the
air-conditioning circuit.
[0020] Further features and advantages of the invention can be
found in the following description and in the following drawings,
to which reference is made. In the drawings:
[0021] FIG. 1 shows a schematic view of an air-conditioning circuit
according to the invention with a primary circuit for a coolant and
a secondary circuit for a cooling fluid;
[0022] FIG. 2 shows a sectional view of a plate-type heat exchanger
according to the invention along the sectional line II-II in FIG.
3;
[0023] FIG. 3 shows a plan view of the plate-type heat exchanger
according to FIG. 2 in a stacking direction;
[0024] FIG. 4 shows a schematic view of the plate-type heat
exchanger according to FIG. 2 with connections for the coolant and
cooling fluid which are arranged on the same lateral surface of the
plate-type heat exchanger;
[0025] FIG. 5 shows a schematic view of the plate-type heat
exchanger according to FIG. 2 having connections for coolant and
cooling fluid which are arranged on opposite lateral surfaces of
the plate-type heat exchanger;
[0026] FIG. 6 shows a direction of flow diagram with associated
temperature profile diagram according to a first embodiment of the
invention;
[0027] FIG. 7 shows a direction of flow diagram with associated
temperature profile diagram according to a second embodiment of the
invention;
[0028] FIG. 8 shows a direction of flow diagram with associated
temperature profile diagram according to a third embodiment of the
invention;
[0029] FIG. 9 shows a direction of flow diagram with associated
temperature profile diagram according to a fourth embodiment of the
invention;
[0030] FIG. 10 shows a plate-type heat exchanger according to FIG.
9 with a first arrangement of the connections for the cooling
fluid;
[0031] FIG. 11 shows a plate-type heat exchanger according to FIG.
9 with a second alternative arrangement of the connections for the
cooling fluid;
[0032] FIG. 12 shows a plate-type heat exchanger according to FIG.
9 with a third alternative arrangement of the connections for the
cooling fluid;
[0033] FIG. 13 shows a schematic view of four heat exchanger plates
of a plate-type heat exchanger according to the invention;
[0034] FIG. 14 shows an alternative embodiment of four heat
exchanger plates of a plate-type heat exchanger according to the
invention;
[0035] FIG. 15 shows a view of a detail of the plate-type heat
exchanger according to FIG. 2 with a coolant distributor; and
[0036] FIGS. 16a, 16b and 16c show schematic views of various
embodiments of a coolant distributor according to FIG. 15.
[0037] FIG. 1 shows a schematic drawing of an air-conditioning
circuit 10 for a vehicle with a primary circuit 12 for a coolant
and a secondary circuit 14 for a cooling fluid.
[0038] The vehicle is, for example, a vehicle having an electric
motor, in particular a hybrid vehicle or a pure electric vehicle,
with a battery which is to be cooled by the air-conditioning
circuit.
[0039] In the primary circuit 12, a compressor 16, a condenser 18
and a drier 20 are provided. The primary circuit 12 is divided into
two secondary regions, which can each be closed or opened by a
valve 22.
[0040] In the first secondary region of the primary circuit 12, an
expansion valve 24 and vaporizer 26 are provided. The vaporizer 26
is part of a vehicle air-conditioning system for the passenger
compartment of a vehicle.
[0041] An expansion valve 28 and a plate-type heat exchanger 30 are
provided in the second secondary region of the primary circuit 12.
The plate-type heat exchanger 30 is, furthermore, integrated into
the secondary circuit 14 and permits a cooling fluid in the
secondary circuit 14 to be cooled by the coolant in the primary
circuit 12.
[0042] The secondary circuit 14 has a pump 32 which pumps the
cooling fluid through the secondary circuit 14. The secondary
circuit 14 also comprises a storage device 34 for the cooling
fluid. A first cooling device 36 for a battery and a second cooling
device 38 for an electronic component are arranged at various
positions in the secondary circuit 14. The position of the cooling
devices 36, 38 in the secondary circuit 14 can depend, in
particular, on the required cooling performance.
[0043] FIG. 2 shows a sectional view through the plate-type heat
exchanger 30. A plurality of heat exchanger plates 40 are stacked
one on top of the other in a stacking direction 42, wherein coolant
chambers 44 and cooling fluid chambers 46, which each have an
inflow 48, 52 and an outflow 50, 54 for the coolant and/or the
cooling fluid, are formed alternately between adjacent heat
exchanger plates 40.
[0044] On the right-hand side in FIG. 2, an end plate 56 is
provided which is arranged behind the heat exchanger plates 40 in
the stacking direction. In the embodiment shown, the end plate 56
serves, for example, to attach the plate-type heat exchanger 30.
The end plate 56 can also be part of a housing of the plate-type
heat exchanger 30.
[0045] The heat exchanger plates 40 have, in the plane of their
plates, both a main extent direction 58 and a secondary extent
direction 60 running perpendicular thereto, said main extent
direction 58 and secondary extent direction 60 each running
perpendicular to the stacking direction 42. In FIG. 2, the
secondary extent direction 60 runs perpendicular to the plane of
the drawing.
[0046] The various inflows 48 of the various coolant chambers 44
lie in a straight line and therefore form a common inflow
connection 49 for all the coolant chambers 44. At the common inflow
connection 49, a connection component 62 is provided which permits
direct attachment to the expansion valve 28 to the plate-type heat
exchanger 30. Such expansion valves 28 have a small lateral
distance between the inflow duct and the outflow duct. In the
embodiments according to the invention, these ducts are coaxial to
the inflows 48 and outflows 50.
[0047] In a way which is analogous to the inflows 48 of the
coolant, the inflows 52 of the cooling fluid of the various cooling
fluid chambers 46 also lie along a straight line and form a common
inflow connection 53 for all the cooling fluid chambers. On the
left-hand side of the plate-type heat exchanger 30, a pipe of the
secondary circuit 14 is connected to the common inflow connection
53 of the cooling fluid chambers 46.
[0048] In a way which is analogous to the inflow connections 49,
53, all the outflows 50, 54 for the coolant and/or the cooling
fluid are embodied as common outflow connections 51, 55.
[0049] FIG. 3 shows a plan view of the plate-type heat exchanger 30
in the stacking direction 42. The heat exchanger plates 40 are
substantially elongate and rectangular, and the main extent
direction 58 is in the longitudinal direction of the heat exchanger
plates 40. Shown in the lower region of the plate-type heat
exchanger 30 is the connection component 62 with the common inflow
connection 49 of all the coolant chambers 44, and with the common
outflow connection 51 of all the coolant chambers 44.
[0050] The distance between the inflow 48 and outflow 50 of the
coolant of the coolant chambers 44 is small compared to the extent
of the heat exchanger plates 40 in the main extent direction 58. As
is shown in the following figures, this small distance permits the
expansion valve 28 to be mounted directly on the plate-type heat
exchanger 30 without pipes or lines for the coolant being required
between the expansion valve 28 and the plate-type heat exchanger
30.
[0051] The common inflow connection 53 and the common outflow
connection 55 of all the cooling fluid chambers 46 of the
plate-type heat exchanger 30 are in turn arranged with small
spacing in the upper region of the plate-type heat exchanger
30.
[0052] FIG. 4 shows a schematic view of the plate-type heat
exchanger 30 in a plan view in the direction of the secondary
extent direction 60. As can be clearly seen in this perspective,
the common inflow connection 49 and the common outflow connection
51 for all the coolant chambers 44, and the common inflow
connection 53 and the common outflow connection 55 for all the
coolant chambers 46, are arranged on the same lateral surface of
the plate-type heat exchanger 30 with respect to the stacking
direction 42.
[0053] FIG. 5 shows an alternative arrangement of the inflow
connection 53 and of the outflow connection 55 of the cooling fluid
chambers 46 on the opposite side surface of the plate-type heat
exchanger 30 with respect to the stacking direction 42. The inflow
connection 49 and the outflow connection 51 of the cooling fluid
chambers 44 have the common connection component 62, on which the
expansion valve 28 is directly provided.
[0054] In each case a pipeline element of the secondary circuit 14
is connected to the inflow connection 53 and to the outflow
connection 55 of the cooling fluid chambers 46.
[0055] FIG. 6 shows the flow profile of the coolant in the coolant
chambers 44 and the profile of the cooling fluid in the cooling
fluid chambers 46 of a first embodiment of the plate-type heat
exchanger 30, and the temperature profile of the coolant and of the
cooling fluid.
[0056] The coolant passes via the inflow 48 into the coolant
chamber 44 which is formed by two adjacent heat exchanger plates
40. The coolant chamber 44 is in its entirety a U-shaped flow duct
64, wherein the inflow 48 of the coolant is arranged at the end of
the first limb, and the outflow 50 is arranged at the end of the
second limb, of the U-shaped flow duct 64. The two limbs of the
U-shaped flow duct 64 are separated by an intermediate wall 66.
[0057] The "U" extends over approximately the entire length of the
heat exchanger plates 40.
[0058] The cooling fluid chamber 46 is embodied as a U-shaped flow
channel 68 for the cooling fluid, in the same way by an
intermediate wall 66. The inflow 52 of the cooling fluid chamber 46
is arranged at the end of the first limb, and the outflow 54 is
arranged at the end of the second limb, of the U-shaped flow duct
68 in the cooling fluid chamber 46. The U shape of the flow duct 68
for the cooling fluid is therefore inverted compared to the
U-shaped flow duct 64 of the coolant, wherein the limbs of the two
flow ducts 64, 68 rest one on the other.
[0059] In the embodiment according to FIG. 6, the directions of
flow of the coolant and cooling fluid in adjoining coolant chambers
44 and cooling fluid chambers 46 in the two limbs are respectively
opposed to one another.
[0060] FIG. 6 also shows the temperature profile in the first limb
A from position A.sub.1 to A.sub.2, and in the second limb B from
the position B.sub.1 to B.sub.2 in both chambers 44, 46. Given an
inflow temperature of the cooling fluid at A.sub.2 of 10.degree. C.
and an outflow temperature of the cooling fluid at B.sub.1 of
4.degree. C. as well as an inflow temperature of the coolant at
A.sub.1 of 4.degree. C. and an outflow temperature of the coolant
at B.sub.2 of 1.degree. C., an effective difference in temperature
.DELTA.tlog of 5.1 K occurs in the limb A, an effective difference
in temperature .DELTA.tlog of 3.6 K occurs in the limb B, and
overall an average difference in the temperature .DELTA.tlog of 4.4
K respectively occurs between adjacent chambers 44, 46. The higher
the difference in temperature between the coolant and the cooling
fluid, the better the exchange of heat between the two.
[0061] FIG. 7 shows a second embodiment of the plate-type heat
exchanger 30, wherein the design is essentially identical to the
first embodiment. The second embodiment differs from the first in
that the direction of flow in the coolant chamber 44 has been
inverted. In the coolant chamber 44, the inflow 48 is therefore
interchanged with the outflow 50 compared to the first
embodiment.
[0062] The direction of flow in adjoining coolant chambers 44 and
cooling fluid chambers 46 is therefore the same.
[0063] The coolant now firstly flows through the limb B of the
U-shaped flow duct 64 from B.sub.1 to B.sub.2 and in the process
cools from 4.degree. C. to 2.degree. C. The coolant subsequently
flows through the limb A from A.sub.1 to A.sub.2, wherein it cools
from 2.degree. C. to 1.degree. C. The saturation temperature is
0.degree. C. As is apparent from the temperature profile diagrams,
the difference in temperature in the limb A is greater than in the
preceding embodiment, wherein the effective difference in
temperature at .DELTA.tlog is 7 K. In the limb B, the difference in
temperature is, in contrast, somewhat smaller and is 2.5 K at
.DELTA.tlog. The average effective difference in temperature across
the entire flow duct is 4.7 K at .DELTA.tlog. By making the
directions of flow the same in adjoining coolant chambers 44 and
cooling fluid chambers 46, an improved difference in temperature
can be surprisingly achieved with the U-shaped flow ducts, as a
result of which the effectiveness of the plate-type heat exchanger
30 is increased.
[0064] FIG. 8 shows a third embodiment of the plate-type heat
exchanger 30. The direction of flow in the U-shaped flow ducts 64,
68 of the coolant chambers 44 and/or of the cooling fluid chambers
46 is identical to the second embodiment. The third embodiment
differs from the second embodiment only in that the difference in
pressure across the limb B of the U-shaped flow duct 64 for the
coolant is between 70% and 100%, preferably between 80% and 92% of
the overall difference in pressure, while the difference in
pressure across the limb A is between 0% and 30%, preferably
between 8% and 20% of the overall difference in pressure. In the
limb B, the first limb in the direction of flow of the coolant, the
coolant cools to a large degree and reaches 0.5.degree. C. in the
example shown. The cooling results from the static pressure which
drops owing to the pressure loss, and owing to the resulting
lowering of the coolant saturation temperature.
[0065] In contrast, no further cooling of the coolant takes place
in the limb A since the saturation temperature only now drops at
minimum by approximately 0.5 K due to the small pressure loss in
the limb A. However, this drop in temperature has a superimposed
coolant overheating of 1 K, with the result that the temperature at
the coolant outlet A.sub.2 of the limb A is even 0.5 K higher than
at the inlet A.sub.1. In this way, a very large difference in
temperature is possible between the coolant chamber 44 and the
cooling fluid chamber 46 in the region of limb A, wherein the
effective difference in temperature at .DELTA.tlog is 7.6 K. In the
limb B, the effective difference in temperature at .DELTA.tlog is
3.2 K. The average effective difference in temperature between the
two limbs is 5.4 K at .DELTA.tlog, as a result of which a further
improvement was achieved in the effectiveness of the plate-type
heat exchanger 30.
[0066] The differences in pressure in the two limbs of the U-shaped
flow duct 64 for the coolant can be achieved in various ways. In
the example shown, the difference in pressure is achieved by a
different flow resistance in the two limbs of the flow duct 64. For
this purpose, different fin arrangements of the flow ducts or
various inserts in the flow ducts are provided. Alternatively, the
two limbs can also be embodied with a different flow cross section,
by virtue of the fact that, for example, the intermediate wall 66
does not divide the two limbs of the U-shaped flow duct 64
uniformly.
[0067] FIG. 9 shows a fourth embodiment of the plate-type heat
exchanger 30, wherein only the flow duct 64 for the coolant in the
coolant chambers 44 is embodied in a U shape. The position of
expansion valve 28 in the coolant chamber 44 is shown by dotted
lines. The embodiment of the coolant chambers 44 and the direction
of flow of the coolant through the U-shaped flow duct 64 is
identical to the third embodiment of the plate-type heat exchanger
30. The fourth embodiment differs from the preceding embodiments in
that the cooling fluid chambers 46 have a flow duct 70 which runs
from the inflow 52 of the cooling fluid at the one end of the heat
exchanger plates 40, parallel to the main extent direction 58 to an
outflow 54 of the cooling fluid at the opposite end of the heat
exchanger plates 40.
[0068] The difference in temperature diagrams at the top and bottom
in FIG. 9 relate to the regions of the limbs A and B of the coolant
chambers 44. The regions A and B are part of the same flow duct 70
through which there is a flow in one direction in the adjacent
cooling fluid chambers 46. The temperature profile of the cooling
fluid is therefore the same in both regions.
[0069] The temperature profile of the coolant corresponds to the
temperature profile of the coolant in the third embodiment of the
plate-type heat exchanger 30.
[0070] The effective difference in temperature in the limb A is
5.64 K at .DELTA.tlog, and the effective difference in temperature
in the region of the limb B is 4.63 K at .DELTA.tlog.
[0071] In the embodiment shown in FIG. 9, the flow duct 70 of the
cooling fluid chambers 46 does not need an intermediate wall 66.
All that is therefore necessary is to provide an intermediate wall
66 in the coolant chambers 44. An intermediate wall 66 is therefore
necessary only in every second chamber in the plate-type heat
exchanger 30, which simplifies the design of the plate-type heat
exchanger 30.
[0072] Various connection variants for connecting the plate-type
heat exchanger 30 to the secondary circuit 14 are provided in the
FIGS. 10, 11 and 12.
[0073] FIG. 10 shows a perspective view of the plate-type heat
exchanger 30, wherein the expansion valve 28 is provided at the
bottom on the left-hand side of the plate-type heat exchanger 30.
Owing to the space requirement of the expansion valve 28, the
outflow connection 55 for the cooling fluid is possible at the same
end in the main extent direction 58 of the plate-type heat
exchanger 30 only on the lateral surface, lying opposite the
expansion valve 28, in the stacking direction 42. The inflow
connection 53 which lies at the top in the main extent direction 58
can lie on the same lateral surface in the stacking direction 42 as
the outflow connection 55, as is shown by a dotted line in FIG. 10,
on the opposite lateral surface with respect to the stacking
direction 42.
[0074] In the plate-type heat exchanger 30 which is shown in FIG.
11, an additional end plate 56 is provided on the lateral surface,
lying opposite the expansion valve 28, of the plate-type heat
exchanger 30 in the stacking direction 42. The end plate 56 forms a
flow duct, indicated by the dotted line, for the cooling fluid,
which flow duct connects the common outflow connection 55 of the
heat exchanger plates 40 to a connection 72 for the cooling fluid
system of the secondary circuit 12. In this way it is possible for
the line systems of the secondary circuit 14 to each be provided at
the same end in the main extent direction 58 of the plate-type heat
exchanger 30, even though the common inflow and outflow connections
53, 55 of the cooling fluid chambers 46 lie at opposite ends of the
plate-type heat exchanger 30 in the main extent direction 58.
[0075] FIG. 12 shows a similar embodiment, wherein the cooling
fluid connections of the secondary circuit 14 lie on opposite sides
of surfaces of the plate-type heat exchanger 30 in the stacking
direction 42.
[0076] FIG. 13 in turn represents an embodiment of the plate-type
heat exchanger 30, wherein the heat exchanger plates 40 are each of
planar design and are spaced apart by wall elements 74 in order to
form the coolant chambers 44 and the cooling fluid chambers 46.
Further wall elements form the intermediate wall 66, which connects
the adjacent heat exchanger plates 40.
[0077] FIG. 14 shows a further embodiment of the plate-type heat
exchanger 30, wherein in each case two adjacent heat exchanger
plates 40 have a shaped section 76, which shaped sections together
form the intermediate wall 66 of the cooling fluid chambers 46. The
intermediate wall 66 of the coolant chambers 44 is, in contrast,
formed, in a way which is analogous to FIG. 13, by a wall element
which connects the adjacent heat exchanger plates 40 to one
another.
[0078] Inserts 78, which divide the coolant chambers 44 or cooling
fluid chambers 46 into small parallel ducts which run along the
limbs A and B in FIGS. 6 to 9, are provided in the coolant chambers
44 and the cooling fluid chambers 46 in FIGS. 13 and 14.
[0079] FIG. 15 shows a view of a detail of the plate-type heat
exchanger 30 according to FIG. 2, wherein a throttle direction 80
is provided in the region of the connection component 62. In the
embodiment shown in FIG. 15, the throttle device 80 is a pipe with
calibrated diameter which projects from the connecting flange at
least partially into one or more coolant chambers 44. A filter 82
is provided in front of the throttle device 80.
[0080] FIG. 16a illustrates an embodiment of a coolant distributor
81 of a simple design, wherein an opening which is relatively large
compared to the throttle device 80 is provided at the common inflow
connection 49 of the coolant chambers 44, which opening causes only
part of the overall difference in pressure between the high
pressure and low pressure; the rest of the difference in pressure
is compensated by the expansion valve 28.
[0081] FIG. 16b shows an embodiment of the coolant distributor with
a pipe with a calibrated diameter which extends into the common
inflow connection 49 of the coolant chambers 44.
[0082] When the coolant exits the reduced opening 81 or the pipe
with a calibrated diameter, the mixture of coolant phase is
swirled, wherein homogenization of the mixture takes place and a
more uniform distribution among the various coolant chambers 44 is
made possible. In this way, a uniform cooling performance in all
the coolant chambers 44 is achieved.
[0083] FIG. 16c shows a coolant distributor 81 in the form of a
distributor insert which permits homogenous distribution of the
coolant phase mixture among the various coolant chambers 44 of the
plate-type heat exchanger 30.
* * * * *