U.S. patent application number 14/917833 was filed with the patent office on 2016-10-20 for thermoelectric module, thermoelectric device, heat exchanger and egr loop.
This patent application is currently assigned to Valeo Systemes Thermiques. The applicant listed for this patent is VELEO SYSTEMS THERMIQUES. Invention is credited to Kamel Azzouz, Georges De Pelsemaeker, Cedric De Vaulx.
Application Number | 20160305304 14/917833 |
Document ID | / |
Family ID | 50069029 |
Filed Date | 2016-10-20 |
United States Patent
Application |
20160305304 |
Kind Code |
A1 |
Azzouz; Kamel ; et
al. |
October 20, 2016 |
THERMOELECTRIC MODULE, THERMOELECTRIC DEVICE, HEAT EXCHANGER AND
EGR LOOP
Abstract
The invention relates to a thermoelectric module (1), comprising
at least one thermoelectric element (3) allowing the generation of
an electric current from a temperature gradient applied between two
of its active faces (4a, 4p), a first so-called hot circuit (2)
able to allow the flow of a first fluid in a heat exchange
relationship with one of said active faces and a sheath (8)
surrounding said thermoelectric elements (3) and said hot circuit
(2) such that the sheath (8) is arranged to establish thermal
contact between a so-called cold liquid with a temperature lower
than that of the first fluid, and the other of said active faces
and to hermetically separate said cold liquid on the one hand and
said thermoelectric element(s) (3) and said hot circuit (2) on the
other hand. The invention also relates to a thermoelectric device
comprising at least one module as described and a heat exchanger
comprising such a device.
Inventors: |
Azzouz; Kamel; (Paris,
FR) ; De Pelsemaeker; Georges; (Poigny-la-foret,
FR) ; De Vaulx; Cedric; (Autouillet, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VELEO SYSTEMS THERMIQUES |
Le Mesnil Saint Denis |
|
FR |
|
|
Assignee: |
Valeo Systemes Thermiques
Le Mesnil Saint Denis
FR
|
Family ID: |
50069029 |
Appl. No.: |
14/917833 |
Filed: |
September 9, 2014 |
PCT Filed: |
September 9, 2014 |
PCT NO: |
PCT/EP2014/069228 |
371 Date: |
May 6, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01N 5/025 20130101;
F28D 7/1692 20130101; F28D 21/0003 20130101; H01L 35/30 20130101;
Y02T 10/166 20130101; Y02T 10/12 20130101; F02M 26/30 20160201;
Y02T 10/16 20130101; F25B 21/02 20130101 |
International
Class: |
F01N 5/02 20060101
F01N005/02; F25B 21/02 20060101 F25B021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2013 |
FR |
1358714 |
Claims
1. A thermoelectric module , comprising: at least one
thermoelectric element for generating an electric current from a
temperature gradient applied between two of its active faces a
first hot circuit for allowing the circulation of a first fluid in
heat exchange relation with one of said active faces and a cladding
surrounding said thermoelectric element or elements and said hot
circuit, such that the cladding is arranged to establish a thermal
contact between a cold liquid, of a temperature lower than that of
the first fluid, and another of said active faces, and hermetically
separate said cold liquid and said thermoelectric element or
elements and said hot circuit.
2. The thermoelectric module as claimed in claim 1, in which the
thermoelectric element is of annular form such that it comprises an
inner face, corresponding to the active face in heat exchange
relation with the hot circuit, and an outer face, corresponding to
the other of said active faces.
3. The thermoelectric module as claimed in claim 2, in which the
thermoelectric element is of flattened cross section.
4. The thermoelectric module as claimed in claim 1, in which the
cladding is electrically insulating.
5. The thermoelectric module as claimed in claim 1, in which the
thermoelectric module comprises separators electrically insulating
two neighboring thermoelectric elements at one of their active
faces.
6. The thermoelectric module as claimed in claim 5, in which the
cladding comprises said separators.
7. The thermoelectric module as claimed in claim 1, in which the
cladding is heat-shrinkable.
8. A thermoelectric device comprising; a casing; and at least one
thermoelectric module as claimed in claim 1, said module being
inserted into the casing and said casing comprising a first zone in
which said cold liquid is intended to be in contact with said
cladding.
9. The thermoelectric device as claimed in claim 8, in which said
casing defines at least partly, a second circuit in which said cold
liquid is intended to circulate.
10. A heat exchanger, comprising a thermoelectric device as claimed
in claim 8, said easing comprising a second zone which the hot
circuit is configured to be directly in contact with the cold
liquid.
11. The heat exchanger as claimed in claim 10, in which the first
zone and the second zone are positioned in series in the direction
of circulation of the hot fluid.
12. The heat exchanger as claimed in claim 11, in which the first
circuit is configured such that the first zone is situated upstream
of the second zone in the direction of circulation of the hot
fluid.
13. The heat exchanger as claimed in claim 10, in which the
exchanger is configured such that the cold liquid is intended to
run parallel through the first zone and the second zone.
14. The heal exchanger as claimed in claim 13, in which the
exchanger comprises a partition separating the first zone from the
second zone such that the cold liquid circulating in the first zone
0 and the cold liquid circulating in the second zone are
separated.
15. The heat exchanger as claimed in claim 10, in which the first
zone and the second zone are situated in series in the direction of
circulation of the cold liquid.
16. The heat exchanger as claimed in 10, in which the first zone
represents 40% to 90% of a volume defined by the interior of the
casing, the second zone representing the remaining portion of said
volume.
17. The heat exchanger as claimed in claim 10, in which the hot
fluid comprises EGR gases.
18. An EGR gas recirculation circuit of a motor vehicle comprising
a thermoelectric device as claimed in claim 8.
19. An EGR gas recirculation circuit of a motor vehicle comprising
a heat exchanger as claimed in claim 10.
Description
[0001] The present invention relates to a thermoelectric module, a
thermoelectric device comprising such a module, a heat exchanger
comprising such a device and an EGR (exhaust gas recirculation)
loop comprising such an exchanger.
[0002] Thermoelectric modules have already been proposed that use
so-called thermoelectric elements, making it possible to generate
an electric current in the presence of a temperature gradient
between two of their opposite faces by the phenomenon known as the
Seebeck effect. These devices comprise a stack of first tubes,
intended for the circulation of the exhaust gases from an engine,
and of second tubes, intended for the circulation of a heat
transfer fluid of a cooling circuit. The thermoelectric elements
are sandwiched between the tubes so as to be subjected to a
temperature gradient originating from the temperature difference
between the hot exhaust gases and the cold coolant.
[0003] These stacks of first tubes, of thermoelectric elements and
of second tubes do however have a complex structure and requires a
precise and complicated assembly to ensure a good contact between
the tubes and the thermoelectric elements.
[0004] The invention aims to improve the situation. For that, it
relates to a thermoelectric module, comprising at least one
thermoelectric element making it possible to generate an electric
current from a temperature gradient applied between two of its
active faces, a first so-called hot circuit, suitable for allowing
the circulation of a first fluid in heat exchange relation with one
of said active faces and a cladding surrounding said thermoelectric
element or elements and said hot circuit such that the cladding is
arranged to establish a thermal contact between a so-called cold
liquid, of a temperature lower than that of the first fluid, and
the other of said active faces and hermetically separate, on the
one hand, said cold liquid and, on the other hand, said
thermoelectric element or elements and said hot circuit.
[0005] Thus, by virtue of the invention, it is possible to use, as
cold fluid, a liquid without the latter circulating in a complex
cold tube stack. There is thus a wide degree of freedom in
designing the thermoelectric devices intended to accommodate said
modules.
[0006] According to different embodiments of the invention, which
will be able to be taken together or separately: [0007] the
thermoelectric element is of annular form such that it comprises an
inner face, corresponding to the active face in heat exchange
relation with the hot circuit, and an outer face, corresponding to
the other of said active faces; [0008] the thermoelectric element
is of flattened cross section; [0009] the cladding is electrically
insulating; [0010] the thermoelectric module comprises separators
electrically insulating two neighboring thermoelectric elements at
one of their active faces; [0011] the cladding comprises said
separators; [0012] the cladding is heat-shrinkable; [0013] the
first circuit comprises at least one tube passing through said
thermoelectric elements.
[0014] The invention relates also to a thermoelectric device
comprising a casing and at least one thermoelectric module as
described previously, said module being inserted into the casing
and said casing comprising a first zone in which said cold liquid
is intended to be in contact with said cladding.
[0015] Advantageously, said casing defines, at least partly, a
second circuit in which said cold liquid is intended to
circulate.
[0016] The invention relates also to a heat exchanger comprising a
thermoelectric device as described previously, said casing
comprising a second zone in which the hot circuit is configured to
be directly in contact with the cold liquid.
[0017] There is thus assured, using just one and the same
exchanger, on the one hand a heat exchange function making it
possible to cool the hot field and to reheat the cold liquid, and,
on the other hand, a function of input from the hot and cold
sources necessary to the operation of the thermoelectric
elements.
[0018] That being the case, the invention relates also to such a
heat exchanger, configured to be positioned in an exhaust gas
recirculation circuit, without said thermoelectric modules
comprising the abovementioned cladding. It will be sufficient for
them to be configured to make it possible to create a temperature
gradient between said active faces of said thermoelectric element
or elements from said hot circuit, passed through by said
recirculated exhaust gases, and a cold circuit passed through by a
cold liquid, notably a cold circuit comprising tubes.
[0019] According to different embodiments of the invention, which
will be able to be taken together or separately: [0020] the first
zone and the second zone are positioned in series in the direction
of circulation of the hot fluid; [0021] the first circuit is
configured such that the first zone is situated upstream of the
second zone in the direction of circulation of the hot fluid;
[0022] the exchanger is configured such that the cold liquid is
intended to run parallel through the first zone and the second
zone; [0023] the exchanger comprises a partition separating the
first zone from the second zone such that the cold liquid
circulating in the first zone and the cold liquid circulating in
the second zone are separated; [0024] the first cone and the second
zone are situated in series in the direction of circulation of the
cold liquid; [0025] the first zone represents 40% to 90% of a
volume defined by the interior of the casing, the second zone
representing the remaining portion of said volume; [0026] the first
zone represents 50% of a volume defined by the inferior of the
casing, the second zone representing 50% of this volume; [0027] the
first zone represents 80% of a volume defined by the interior of
the casing, the second zone representing 20% of this volume; [0028]
the hot fluid comprises EGR gases.
[0029] The invention relates also to an EGR gas recirculation
circuit of a motor vehicle comprising a thermoelectric device or a
heat exchanger as described previously.
[0030] In effect, with the dimension of the exchanger being
reduced, it is possible to incorporate it in an exhaust gas
recirculation duct of the motor vehicle.
[0031] The invention will be better understood in light of the
following description which is given by way of indication and which
is in no way intended to limit it, accompanied by the attached
drawings in which;
[0032] FIG. 1 schematically represents, in exploded perspective, a
thermoelectric module according to the invention;
[0033] FIG. 2 schematically illustrates, in cross section, the
thermoelectric module of FIG. 1;
[0034] FIG. 3 represents, in exploded perspective, a thermoelectric
device comprising said module;
[0035] FIG. 4 schematically illustrates, in transverse cross
section, a heat exchanger according to the invention comprising the
thermoelectric device of the invention;
[0036] FIG. 5 schematically illustrates, in lateral cross section,
a part of the heat exchanger illustrated in FIG. 4.
[0037] The invention relates to a thermoelectric module 1 as
represented in FIGS. 1 and 2. Such a module 1 comprises a first
so-called hot circuit 2, suitable for allowing the circulation of a
first fluid, notably exhaust gases from an engine. The first
circuit 2 here comprises a tube 5.
[0038] The module 1 also comprises a plurality of thermoelectric
elements 3 capable of generating an electric current under the
action of a temperature gradient exerted between two of their
active faces 4a, 4b, Such thermoelectric elements 3 operate,
according to the Seebeck effect, by making it possible to create an
electric current in a load connected between said faces 4a, 4b
subjected to the temperature gradient. As is known to those skilled
in the art, such elements consist, for example, of bismuth and
tellurium (Bi.sub.2Te.sub.3).
[0039] The thermoelectric elements 3 are, for a first part,
elements 3P of a first type, called Pf making it possible to
establish an electric potential difference in one direction, called
positive, when they are subjected to a given temperature gradient,
and, for the other part, elements 3N of a second type, called
making it possible to create an electric potential difference in an
opposite direction, called negative, when they are subjected to the
same temperature gradient. Said thermoelectric elements 3 are, for
example, grouped in pairs, each pair being formed by one said
P-type thermoelectric element and one said N-type thermoelectric
element.
[0040] The thermoelectric elements 3 are here of annular form and
are notably of flattened cross section. The active faces 4a, 4b are
therefore situated on the inner and outer periphery of the annular
form such that the thermoelectric elements 3 has an inner active
face 4a and an outer active face 4b. That thus makes it possible to
have the first circuit 2 at least partly inside the thermoelectric
elements 3 in contact with the inner active face 4a.
[0041] The module 1 also comprises at least one internal ring 6
arranged between the first circuit 2 and the thermoelectric
elements 3, that is to say in contact with the inner face 4a of the
thermoelectric elements 3. The internal ring 6 is electrically and
thermally conductive and links together two thermoelectric elements
3 of a same pair.
[0042] The module 1 further comprises at least one external ring 7
in contact with the outer active face 4b of the thermoelectric
elements 3, The external ring 7 is electrically and thermally
conductive and links together two thermoelectric elements 3 of two
neighboring pairs.
[0043] Said module 1 is thus configured to allow a circulation of
current between the inner active faces 4a of the thermoelectric
elements 3 of a same pair by virtue of the internal rings 6 and a
circulation of current between the outer active faces 4b of two
neighboring thermoelectric elements 3 belonging to two different
pairs by virtue of the external rings 7. In this way, a circulation
of current is established in series from one thermoelectric element
to another, by alternating the P-type and N-type thermoelectric
elements.
[0044] The module 1 of the invention further comprises a hermetic
cladding 8, here surrounding the thermoelectric elements 3 and the
first circuit 2 such that they are situated inside the cladding 8.
The cladding 8 is thus arranged on the side of the outer active
face 4b of the thermoelectric elements. It is here in contact with
the external rings 7.
[0045] This cladding 8 hermetically separates the thermoelectric
elements 3 and the first circuit 2 from the outside of the module
1, that is to say that it prevents any contact of a fluid outside
the module 1 with the thermoelectric elements 3 and the first
circuit 2 situated inside the cladding, as well as, here, with the
internal 6 and external 7 rings. In other words, the assembly is
encapsulated in the cladding 8 which jackets it.
[0046] The cladding 8 is also thermally conductive. It can thus be
positioned in contact with a coolant, called cold liquid, in order
to provide the thermoelectric elements 3, notably via the external
rings 7, with the cold source necessary to provide the temperature
gradient that the thermoelectric elements need to generate
electricity without the liquid entering into contact with the
internal rings 6, the external rings 7, the thermoelectric elements
3 and the first circuit 2.
[0047] The cladding 8 is also electrically insulating. It thus
makes it possible to electrically insulate the external ring 7 and
the thermoelectric elements 3 from the outside of the module 1 and
in particular from the cold liquid intended to be in contact with
the cladding 8.
[0048] The module 1 of the invention will also be able to comprise
separators 9 arranged between the neighboring thermoelectric
elements 3 so as to electrically insulate them from, one another at
one of their active faces 4a, 4b. Thus, the separators electrically
insulate the outer faces 4b of the thermoelectric elements 3 of a
same pair and the inner faces 4a of the neighboring thermoelectric
elements 3 of two different pairs. The separators 9 further help to
promote the seal-tightness of the module provided by the cladding 8
as seen previously.
[0049] In a particular embodiment of the invention, and as
illustrated in FIGS. 1 and 2, it is the cladding 8 which comprises
these separators 9 such that the cladding 8 extends between said
thermoelectric elements. They are for example made in a single
piece with the cladding 8. This notably facilitates the
manufacturing and the assembly of the module 1,
[0050] The cladding 8 is advantageously heat-shrinkable such that
the tight fitting of the cladding 8 on the rest of the module is
facilitated,
[0051] As explained previously, the invention relates also to a
thermoelectric device 10 as illustrated in FIG. 3. This device 10
comprises at least one module 1 as described previously and in
particular a plurality of modules 1. The device 10 also comprises a
casing 11 defining a volume and inside which are inserted the
modules 1. The modules 1 are here stacked one on top of the other
and arranged in two rows side by side.
[0052] The device 10 is configured to have the cold liquid
circulate in contact with said thermoelectric modules 1. Here it is
the casing 11 which defines a second circuit inside which the cold
liquid circulates by passing between said modules 1.
[0053] The device 10 comprises a first zone in which the cold
liquid is intended to be in contact with the cladding of the
modules 1.
[0054] The device 10 also comprises a collecting box 15 situated at
a second longitudinal end 16 of the modules 1. Thus, the hot fluid
can circulate from a first longitudinal end 17 of a first group of
modules 1 to the collecting box 15, which then directs it to a
second group of modules 1 into which it enters by the second
longitudinal end 16. The hot fluid then circulates in the opposite
direction until it exits from the second group of modules 1 then
from the device 10 at the same first longitudinal end 17 of the
modules 1 by which it entered.
[0055] The invention relates also to a heat exchanger 20,
comprising such a device 10, The exchanger then comprises, as
illustrated in FIGS. 4 and 5, a second zone 32, situated inside
said casing 11 and in which the first circuit 2 and the cold liquid
are directly in contact.
[0056] In these exemplary embodiments, the first zone 31 and the
second zone 32 are positioned in series according to the first
circuit 2, that is to say in the direction of circulation of the
hot fluid. Thus, the hot fluid enters into the exchanger 20 in the
first zone 31, passes through the first circuit 2 in the modules 1
and continues to pass through the first circuit 2 by exiting from
the modules 2 and therefore by entering into the second zone 32
before exiting from the exchanger 20.
[0057] It can be noted that the first circuit 2 is, here,
continuous over the entire path of the hot fluid notably between
the first and second zones 31, 32, that is to say that the tubes 5
are continuous. Thus, the first zone 31 allows the modules 1 to
generate electricity by virtue of the temperature gradient created
by the hot fluid and the cold liquid. The hot fluid is then
insulated from the cold liquid by the internal ring, the
thermoelectric elements 3, the external ring and the cladding 8. It
therefore changes temperature only very little when it passes
through the modules 1 which guarantee the electrical generating
efficiency of the modules 1.
[0058] On the other hand, when the hot fluid is in the second zone
32, the second circuit is directly in contact with the cold liquid.
The heat exchange between the two fluids is therefore much greater
and the cooling of hot fluid will then be able to be performed.
[0059] It can be noted that the invention makes it possible to
allow the zones 31, 32 to spread in the exchanger 20 as a function
of the electrical and thermal efficiency that is desired. Thus, to
increase the production of electricity, the size of the first zone
31 is increased whereas, to increase the cooling of the hot fluid,
the dimensions of the second zone 32 are increased. FIG. 4
illustrates an example in which 50% of the internal volume defined
by the casing 11 is occupied by the first zone 31 and 50% by the
second zone 32. In the exemplary embodiment of FIG. 5, 80% of the
internal volume is occupied by the first zone 31 and 20% by the
second zone 32.
[0060] The liquid can pass, for example, parallel through the first
and second zones 31, 32 as illustrated in FIG. 4. The exchanger
here comprises a partition 21 separating the cold liquid in contact
with the first circuit 2 in the second zone 32 from the cold liquid
in contact with the modules 1 in the first zone 31. The cold liquid
in contact with the modules 1 exchanges only very little heat with
the first circuit 2 which guarantees the efficiency of the
thermo-generating elements.
[0061] According to an alternative, the first zone and the second
zone are situated in series in the direction of circulation of the
liquid. The cold liquid firstly adds the cold source to the modules
1 without exchanging much heat with the first circuit 2 then
directly exchanges heat with the first circuit 2 in order to cool
the hot fluid, or vice versa to favor the heat exchange, the
temperature gradient for the thermoelectric function then remaining
sufficient given the high heat capacity of the cold fluid, the
latter being liquid.
* * * * *