U.S. patent application number 13/632468 was filed with the patent office on 2013-01-31 for temperature control element and temperature control device for a vehicle.
This patent application is currently assigned to BEHR GMBH & CO. KG. The applicant listed for this patent is Behr GmbH & Co. KG. Invention is credited to Holger BREHM, Juergen GRUENWALD, Dirk NEUMEISTER, Holger SCHROTH.
Application Number | 20130025295 13/632468 |
Document ID | / |
Family ID | 44526162 |
Filed Date | 2013-01-31 |
United States Patent
Application |
20130025295 |
Kind Code |
A1 |
BREHM; Holger ; et
al. |
January 31, 2013 |
TEMPERATURE CONTROL ELEMENT AND TEMPERATURE CONTROL DEVICE FOR A
VEHICLE
Abstract
A temperature control element for a vehicle is provided that
includes a first Peltier element layer, a second Peltier element
layer, a first electrically conductive heat conductor layer for
conducting a first heat transfer fluid and a second electrically
conductive heat conductor layer for conducting a second heat
transfer fluid, wherein the first Peltier element layer, the second
Peltier element layer, the first heat conductor layer, and the
second heat conductor layer are disposed in the form of a stack, so
that the first heat conductor layer and/or the second heat
conductor layer is disposed between the first Peltier element layer
and the second Peltier element layer, and wherein an electrical
current conducted through the stack brings about a temperature
control of the first heat conductor layer and the second heat
conductor layer due to a Peltier effect.
Inventors: |
BREHM; Holger;
(Erdmannhausen, DE) ; GRUENWALD; Juergen;
(Ludwigsburg, DE) ; NEUMEISTER; Dirk; (Stuttgart,
DE) ; SCHROTH; Holger; (Maulbronn, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Behr GmbH & Co. KG; |
Stuttgart |
|
DE |
|
|
Assignee: |
BEHR GMBH & CO. KG
Stuttgart
DE
|
Family ID: |
44526162 |
Appl. No.: |
13/632468 |
Filed: |
October 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2011/054878 |
Mar 30, 2011 |
|
|
|
13632468 |
|
|
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|
Current U.S.
Class: |
62/3.6 |
Current CPC
Class: |
H01L 35/32 20130101;
B60N 2/5692 20130101 |
Class at
Publication: |
62/3.6 |
International
Class: |
F25B 21/02 20060101
F25B021/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2010 |
DE |
DE102010013467.8 |
May 6, 2010 |
DE |
DE102010019794.7 |
Jul 16, 2010 |
DE |
DE102010027470.4 |
Nov 9, 2010 |
DE |
DE102010043620.8 |
Claims
1. A temperature control element for a vehicle, the temperature
control element comprising: a first Peltier element layer; a second
Peltier element layer; a first electrically conductive heat
conductor layer for conducting a first heat transfer fluid; and a
second electrically conductive heat conductor layer for conducting
a second heat transfer fluid, wherein the first Peltier element
layer, the second Peltier element layer, the first heat conductor
layer, and the second heat conductor layer are arranged in the form
of a stack such that the first heat conductor layer and/or the
second heat conductor layer are arranged between the first Peltier
element layer and the second Peltier element layer, and wherein an
electric current conducted through the stack brings about a
temperature control of the first heat conductor layer and the
second heat conductor layer due to a Peltier effect.
2. The temperature control element according to claim 1, further
comprising an additional first electrically conductive heat
conductor layer and/or an additional second electrically conductive
heat conductor layer, which is arranged in the stack separated by
at least one of the first Peltier element layer or second Peltier
element layer from the first heat conductor layer or second heat
conductor layer.
3. The temperature control element according to claim 1, further
comprising an additional second electrically conductive heat
conductor layer, wherein the second heat conductor layer has a
first electrical contact and the additional second heat conductor
layer a second electrical contact, and wherein the first Peltier
element layer and the second Peltier element layer are arranged
between the second heat conductor layer and the additional second
heat conductor layer and the first heat conductor layer is arranged
between the first Peltier element layer and the second Peltier
element layer.
4. The temperature control element according to claim 1, further
comprising: an additional first heat conductor layer and an
additional second heat conductor layer, wherein the first heat
conductor layer has a first electrical contact and the additional
first heat conductor layer a second electrical contact; and an
electrical line configured to connect the second heat conductor
layer to the additional second heat conductor layer, wherein the
first heat conductor layer and the second heat conductor layer are
arranged between the first Peltier element layer and the second
Peltier element layer, wherein the first Peltier element layer and
the second Peltier element layer are arranged between the
additional first heat conductor layer and the additional second
heat conductor layer, and wherein a galvanic and thermal insulation
layer is arranged between the first heat conductor layer and the
second heat conductor layer.
5. The temperature control element according to claim 1, wherein
the first Peltier element layer has at least two first Peltier
element conductors arranged adjacent to one another and wherein the
second Peltier element layer has at least two second Peltier
element conductors arranged adjacent to one another.
6. The temperature control element according to claim 1, wherein
the first Peltier element layer and the second Peltier element
layer each have at least one first Peltier element conductor and at
least one second Peltier element conductor, which are arranged
adjacent to one another and connected to one another in an
electrically conductive manner so that the electric current
conducted through the stack flows serially through the first
Peltier element conductor and second Peltier element conductor.
7. The temperature control element according to claim 1, wherein
the first heat conductor layer is configured as a coolant channel
and the second heat conductor layer is configured as a rib
element.
8. The temperature control element according to claim 1, wherein
the first heat conductor layer on an outer side has a galvanic
insulation layer, which is surrounded by a conductor layer, which
is configured to enable a current flow between the first Peltier
element layer and the second Peltier element layer.
9. The temperature control device according to claim 3, wherein a
plurality of temperature control elements are interconnected in a
series connection via respective first contact and second
contact.
10. The temperature control device according to claim 8, wherein a
galvanic insulation layer is arranged between two each of the
plurality of temperature control elements.
11. A temperature control device for a vehicle, the temperature
control device comprising: a first heat conductor layer for
conducting a first heat transfer fluid; a Peltier element layer
that has a plurality of Peltier elements, which are arranged spaced
apart from one another and in each case comprise a plurality of
Peltier element conductors; and a second heat conductor layer for
conducting a second heat transfer fluid, wherein the layers are
arranged in the form of a stack such that the Peltier element layer
are arranged between the first heat conductor layer and the second
heat conductor layer.
12. The temperature control device according to claim 11, wherein
the plurality of Peltier elements covers a maximum of a tenth of a
total area of the Peltier element layer.
13. The temperature control device according to claim 11, further
comprising an additional Peltier element layer, which has a
plurality of additional Peltier elements, which are arranged spaced
apart from one another and in each case comprises a plurality of
additional Peltier element conductors and an additional first heat
conductor layer for conducting the first heat transfer fluid,
wherein the additional Peltier element layer is arranged in the
stack between the second heat conductor layer and the additional
first heat conductor layer.
14. The temperature control device according to claim 11, further
comprising: a thermal insulation layer; an additional first heat
conductor layer for conducting the first heat transfer fluid; and
an additional Peltier element layer, which has a plurality of
additional Peltier elements, which are arranged spaced apart from
one another and in each case comprise a plurality of additional
Peltier element conductors, wherein the thermal insulation layer is
arranged in the stack adjacent to the second heat conductor layer
and the additional first heat conductor layer in the stack between
the thermal insulation layer and the additional Peltier element
layer.
15. The temperature control device according to claim 11, further
comprising a switching device, which is configured to conduct the
second heat transfer fluid in a first operating mode of the
temperature control device or temperature control element through
the second heat conductor layer and an additional second heat
conductor layer and in a second operating mode of the temperature
control device either through the second heat conductor layer or
through the additional second heat conductor layer.
Description
[0001] This nonprovisional application is a continuation of
International Application No. PCT/EP2011/054878, which was filed on
Mar. 30, 2011, and which claims priority to German Patent
Application No. DE 10 2010 013 467.8, which was filed in Germany on
Mar. 30, 2010, German Patent Application No. DE 10 2010 019 794.7,
which was filed in Germany on May 6, 2010, German Patent
Application No. DE 10 2010 027 470.4, which was filed in Germany on
Jul. 16, 2010, and German Patent Application No. DE 10 2010 043
620.8, which was filed in Germany on Nov. 9, 2010, and which are
all herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a temperature control
element and a temperature control device for a motor vehicle,
particularly for an electric or hybrid vehicle.
[0004] 2. Description of the Background Art
[0005] No combustion waste heat for heating the passenger area is
available in electric vehicles. Electrically resistive heating
requires a considerable increase in battery capacity, which is
generally very cost-intensive. Alternative heating methods and also
cooling methods are therefore sought to reduce the need for
electric power to maintain passenger comfort.
[0006] PTC auxiliary heaters or PTC thermistor auxiliary heaters
are a possibility for electric vehicles without having to carry a
fuel such as gasoline, bioethanol, etc., to cover the heating
requirement for the passenger compartment in colder times of the
year. PTC auxiliary heaters disposed on the air side are already
being mass-produced for vehicles with at times limited waste heat,
for instance, for modern diesel vehicles during a cold start. A
form of realization here is, for example, a heater principle with
layers of ribbing, glued one on top of the other, with PTC stones
between the layers. In fact, this design is especially simple,
because no frame, housing, tube, or the like surrounding the
heating unit or parts thereof are needed, but there is a serial
material connection with the particular adjacent layers because of
the adhesive bonds. Because in this simple construction the ribbing
itself carries current, but it is suitable solely for low voltage
applications, e.g., for the 12 V on-board electrical system.
[0007] Another approach is a realization of a heating unit using
Peltier technology. In this regard, e.g., prototypes of a heating
unit with an alternative cooling function to support the AC circuit
have already been proposed. In these prototypes, however, the
design principle appears to be relatively complicated and
three-dimensional; e.g., a great depth is necessary. The Peltier
effect of thermoelectric materials is already utilized in niche
applications for cooling, for instance, cooling of electronic
components or in camping coolers. For applications in the
automobile, the efficiency has been regarded thus far as being too
low; in contrast the converse effect of current generation from
temperature differences by means of thermoelectrics in the exhaust
gas line of vehicles driven by internal combustion engines is
propagated by well-known manufacturers in expert circles and
developed in the direction of mass-production readiness. Thus far,
the conventional cooling circuit is employed for air conditioning
the passenger area, and electrical resistance heaters are largely
relied upon for heating in first generation electric vehicles.
[0008] In the case of purely electric heating, high-cost electrical
energy is converted to low-cost thermal energy. Two observations
indicate otherwise. On the one hand, provision of electrical
storage capacity, e.g., by means of Li-ion batteries, costs about
500-700 /kWh. The thus far envisaged technologies with Peltier
elements are more costly to realize than heating with PTC auxiliary
heaters because of the greater complexity of the electrical
interconnections of alternating p- and n-doped components in the
electrical series connection. Electrical insulators are usually
also thermally insulating and worsen the heat transfers. The
thermoelectrics at high driving temperature gradients are affected
even more greatly than conventional heat pumps by the reduction of
the COP or efficiency. Resistance heaters achieve only a COP=1 and
have a great negative effect on the cruising range of the electric
vehicle. The cooling circuit in principle works with an acceptable
COP, but contains many individual components and must be topped up
regularly with coolant. Overall, separate units for heating
(heating unit) and cooling (cooling circuit) must be installed for
each of the two functions.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the present invention to
provide an improved temperature control element and an improved
temperature control device.
[0010] The present invention is based on the realization that by a
skillful series connection of Peltier elements, a heating or
cooling unit in the layer design can be enabled in such a way that
in each case similarly doped Peltier elements are arranged adjacent
in a layer.
[0011] The use of Peltier elements differs from the use of PTC
stones, among others, in the fact that two differently doped
materials, therefore p- and n-doped elements, are interconnected.
By default, the Peltier elements form such a configuration that a
hot side of two differently doped Peltier elements and a cold side
of two differently doped Peltier elements are connected in an
electrically conducting manner, so that a series connection results
overall. This type of configuration, however, can hardly be applied
directly to a production-suitable heating or cooling unit, because
the metallic conductors do not form a continuous bar, which goes
beyond two differently doped, directly adjacent elements. The
breaks could be bridged only by an electrical nonconductor. These
nonconductors represent an obstacle for heat transfer on both
sides.
[0012] The approach of the invention describes a heating unit with
a possible cooling function for heating or cooling the passenger
area of an electric vehicle, which can be produced as
cost-effectively as possible with the lowest possible effort and
already usable production technologies, and in addition has a high
efficiency through heat transfer optimization.
[0013] A heating unit of the invention may have simple to produce,
continuous bars for a ribbing and continuous channels for cooling
water, which are made as electrical conductors. A high heat
transfer can be realized by as direct as possible thermal
connection of the Peltier elements on a liquid and/or air side;
this can be attributed in particular to the fact that no electrical
insulators are present in this area as heat barriers.
Advantageously, this type of combination of series and parallel
connections can be adjusted to 12 V. The heat transfer at ribs on
the air side and a cooling water channel can be made two-sided
according to an embodiment. This type of structure offers the
further advantage that a possible thermal insulation effect of a
galvanic separation, e.g., between the ribs, is not problematic,
because there is no temperature gradient here owing to the symmetry
requirement. Overall, there is an important advantage in a smallest
possible departure from heating units already produced according to
existing production methods, e.g., with PTC auxiliary heaters, with
a simultaneously optimal heat transfer. Therefore, an optimal
efficiency or COP (coefficient of performance) results. A basic
design formed according to the approach of the invention here thus
offers the advantage that it differs substantially in two points
from a heating unit with a material connection. First, cooling
water channels are already present as heat sources, for a heating
mode, or as heat sinks, for a cooling mode. And second, an
electrical insulation layer is present in the middle between the
corrugated ribs. Operation of a heating unit of the invention with
Peltier elements for a heating or cooling mode is accordingly such
that net heat flows in sum occur only in the vertical direction and
are to be understood in this way.
[0014] Advantageously, heating without combustion waste heat with a
COP>1 and a combination of the functions of cooling and heating
in one structure are possible. In addition, elimination of coolants
and a simple decentralization through modularity result, because of
the repeating layers and a repeating planar structure within a
layer.
[0015] The present invention provides a temperature control element
for a vehicle, with the following features: a first Peltier element
layer; a second Peltier element layer; a first electrically
conductive heat conductor layer for conducting a first heat
transfer fluid; and a second electrically conductive heat conductor
layer for conducting a second heat transfer fluid, whereby the
first Peltier element layer, the second Peltier element layer, the
first heat conductor layer, and the second heat conductor layer are
arranged in the form of a stack, so that the first heat conductor
layer and/or the second heat conductor layer are arranged between
the first Peltier element layer and the second Peltier element
layer, and whereby an electric current conducted through the stack
brings about a temperature control of the first heat conductor
layer and the second heat conductor layer due to a Peltier
effect.
[0016] The temperature control element can be used, for example, in
an electric or hybrid vehicle, to control the temperature of a
passenger cell in the vehicle. Temperature control in this case can
mean both heating and cooling. The first Peltier element layer and
the second Peltier element layer can be formed from two differently
doped semiconductor materials. Thus, for example, the first Peltier
element layer can be n-doped and the second Peltier element layer
p-doped or, vice versa, the first Peltier element layer can be
p-doped and the second Peltier element layer n-doped. Instead of
semiconductor materials, other suitable conductors can also be used
for the Peltier element layers. The first and second electrically
conductive heat conductor layer can be made from a highly
conductive metal. A current applied to the temperature control
element can enter at one end of the stack into the temperature
control element, pass through the entire stack, and again leave it
at an opposite end, for example, via suitable contacts that are
connected to an electrical line. A heat transfer fluid can flow
through the first and second electrically conductive heat conductor
layer. The first and second heat conductor layer can be arranged in
the stack relative to the first and second Peltier element layer,
so that a temperature generated by the Peltier effect can be
transferred to the heat transfer fluid being conducted in said
layer. According to the Peltier effect and the arrangement of the
heat conductor layers in regard to the Peltier element layers, one
of the heat transfer fluids is always heated and the other cooled
during operation of the temperature control element. The first and
second heat transfer fluid can be in each case, e.g., a gas or a
fluid. According to a temperature control element task to be
achieved, one of the heat transfer fluids can be used to be
conducted to a passenger cell of the vehicle in order to cool or
heat said cell. If the current flow in the temperature control
element is reversed, the heat transfer fluid, which was previously
heated by the temperature control element, can now be cooled or
vice versa. To prevent a leakage current via the heat transfer
fluid, electrical insulation can be arranged between the heat
transfer fluid and a surface, facing the heating fluid, of the heat
conductor layer.
[0017] According to an embodiment, the temperature control element
can comprise an additional first electrically conductive heat
conductor layer and in addition or alternatively an additional
second electrically conductive heat conductor layer. In this case,
the additional first and/or additional second heat conductor layer
can be arranged in the stack separated by at least one of the first
or second Peltier element layer from the first or second heat
conductor layer. For example, the stack can be structured so that
the additional second heat conductor layer, on which the first
Peltier element layer is arranged, is located at the very bottom of
the stack. On this layer, the first heat conductor layer, on which
the second Peltier element layer is located, can be arranged in
turn. The second heat conductor layer can form the closure of the
temperature control element stack. Alternatively, the stack can be
built so that the additional first heat conductor layer forms the
first layer of the stack. On this layer, for example, the first
Peltier element layer, the second heat conductor layer, the first
heat conductor layer, the second Peltier element layer, and the
additional second heat conductor layer can be arranged one after
another, whereby a thermal insulation layer can be arranged between
the second heat conductor layer and the first heat conductor
layer.
[0018] In case that the temperature control element comprises an
additional second electrically conductive heat conductor layer, the
second heat conductor layer can have a first electrical contact and
the additional second heat conductor layer a second electrical
contact. In this case, the first Peltier element layer and the
second Peltier element layer can be arranged between the second
heat conductor layer and the additional second heat conductor
layer. The first heat conductor layer can be arranged between the
first Peltier element layer and the second Peltier element layer.
According to this arrangement, a first Peltier effect can be
achieved at the first heat conductor layer, so that the first heat
conductor layer can be heated or cooled according to a polarity of
the current conducted through the stack. According to a Peltier
effect opposite to the first Peltier effect, the second heat
conductor layer can be heated when the first heat conductor layer
is cooled or cooled when the first heat conductor layer is heated.
This arrangement offers the further advantage that no thermally
insulating layer is needed between the individual layers and
differently temperature-controlled heat conductor layers are always
separated by a Peltier element layer. In a stacking of the
temperature control element with another similar temperature
control element, moreover, only a galvanic separation and no
thermogalvanic separation between the temperature control elements
are necessary, because here two heat conductor layers are arranged
adjacent to one another that are exposed to the same Peltier effect
and thus have a similar temperature.
[0019] Alternatively, the temperature control element can comprise
an additional first heat conductor layer and an additional second
heat conductor layer. The first heat conductor layer can have a
first electrical contact, and the additional first heat conductor
layer can have a second electrical contact. Further, the
temperature control element can have an electrical line for
connecting the second heat conductor layer to the additional second
heat conductor layer. In this regard, the first heat conductor
layer and the second heat conductor layer can be arranged between
the first and second Peltier element layer and the first Peltier
element layer and the second Peltier element layer are arranged
between the additional first heat conductor layer and the
additional second heat conductor layer. A galvanic and thermal
insulation layer can be arranged, moreover, between the first heat
conductor layer and the second heat conductor layer. According to
this arrangement, an electric current can enter the temperature
control element at the first electrical contact and from there pass
through the second Peltier element layer, the second heat conductor
layer, and via the electrical line the additional second heat
conductor layer, the first Peltier element layer, and finally the
additional first heat conductor layer. At the second electrical
contact, the electric current can be conducted out of the
temperature control element and perhaps into an additional
temperature control element.
[0020] According to a further embodiment, the different heat
conductor layers of the temperature control element can also be
connected together via additional electrical lines. The additional
lines in this regard can be arranged in each case at the ends,
opposite to the lines, of the particular heat conductor layers of
the temperature control element. Accordingly, the heat conductor
layers provided with a first or second contact can each have
additional contacts for connecting the additional lines. This type
of two-sided supplying and removal of the electric current on the
left and right at the temperature control element, for example, by
means of cables, can contribute to reducing the current strengths
in the bars or ribs of the various heat conductor layers of the
temperature control element. The disadvantage that in case of a
one-sided connection the current strength at the entrance into the
heat conductor layer, namely, the sum of all currents through the
Peltier element conductors would correspond to a series, which can
lead to unallowable current densities, can thereby be
eliminated.
[0021] The first Peltier element layer can have at least two first
Peltier element conductors arranged adjacent to one another, and
the second Peltier element layer can have at least two second
Peltier element conductors arranged adjacent to one another. A
distance between the individual Peltier elements can be selected
depending on a heat output of the Peltier element conductors. An
electrical insulation can be arranged between the individual
Peltier element conductors. Depending on the expanse of the Peltier
element layers, accordingly many Peltier element conductors can be
arranged adjacent to one another. In this regard, the Peltier
element conductors can be arranged in a planar manner, therefore,
for example, next to one another in both the longitudinal and
transverse direction.
[0022] According to an alternative embodiment, the first Peltier
element layer and the second Peltier element layer can each have at
least one first Peltier element conductor and at least one second
Peltier element conductor. The first and second Peltier element
conductor in this regard can be arranged adjacent to one another
and be connected in an electrically conductive manner. As a result,
the electric current conducted through the stack can flow serially
through the first Peltier element conductor and second Peltier
element conductor. For example, the first Peltier element conductor
can be n-doped and the second Peltier element conductor can be
p-doped, or vice versa. This embodiment of the temperature control
element offers the advantage that perhaps already available
prototypes of heating elements based in Peltier technology can be
used for constructing the temperature control element proposed
here. This results in a saving of time and cost during
production.
[0023] According to an embodiment, the first heat conductor layer
can be configured as a coolant channel and the second heat
conductor layer can be configured as a rib element. For example,
the coolant channel can be formed as a tube for carrying a coolant
fluid. The rib element can be formed, for example, from two bars,
between which a zigzag-shaped or wavelike bent metal band is
arranged, so that, for example, obliquely arranged ribs are formed
between the bars. The second heat transfer fluid, for example, can
be air, which is brought into the vehicle from the vehicle
environment and is passed through the second heat conductor layer,
where it is cooled or heated according to a temperature of the
second heat conductor layer. This type of structure for the second
heat conductor layer advantageously offers a large temperature
transfer area for the fluid passed through the second heat
conductor layer. Of course, the first heat conductor layer can be
configured to carry air and the second heat conductor layer to
carry a fluid. Likewise, the first heat conductor layer can have a
plurality of adjacently arranged coolant channels and the
additional heat conductor layer can have a plurality of adjacently
arranged rib elements.
[0024] The first heat conductor layer can have a galvanic
insulation layer on an outer side. It can be surrounded by a
conductor layer, which can be formed to enable a current flow
between the first Peltier element layer and the second Peltier
element layer. For example, the first heat conductor layer can be
surrounded completely by the conductor layer, or the conductor
layer can be applied to two opposite sides of the first heat
conductor layer and be connected to an electric line. The electric
current flow through the temperature control element stack can be
assured in this way, whereby at the same time the first heat
conductor layer is excluded from an electric current flow. Thus,
leakage currents in the coolant flowing through the first heat
conductor layer can be prevented.
[0025] The first heat conductor layer and the second heat conductor
layer can be configured to provide flow directions, orthogonal to
one another, for the first heat transfer fluid and the second heat
transfer fluid. In this way, inlets and outlets for the different
heat transfer fluids can be arranged on different sides of the
temperature control element.
[0026] The present invention provides further a temperature control
device, which comprises a plurality of temperature control
elements, whereby the plurality of temperature control elements are
interconnected in a series connection via the respective first and
second contacts.
[0027] According to an embodiment, a galvanic insulation layer can
be arranged between two each of the plurality of temperature
control elements. In this way, an electric current flow can be
assured one after the other through all temperature control
elements of the temperature control device. Contacts of a first and
last temperature control device in regard to the current flow can
be connected to a current source. Galvanic insulation layers
arranged between adjacent temperature control elements can,
moreover, provide a thermal insulation between the individual
temperature control elements. This is especially important when two
differently temperature-controlled heat conductor layers are
arranged adjacent to one another in the temperature control device.
The temperature control elements can be interconnected both in a
series connection and in a parallel connection or in a combination
form in the temperature control device.
[0028] The plurality of temperature control elements can be
arranged in at least one stack. In this regard, a dimension of the
temperature control device can be adapted to existing spatial
circumstances by a suitable number of stacked temperature control
elements and/or a horizontal extent of the individual layers of the
plurality of temperature control elements. Of course, the
temperature control device can also be formed from a plurality of
stacks, which are arranged adjacently and are connected via the
respective contacts in a series or parallel connection.
[0029] The present invention provides further a temperature control
device for a vehicle, with the following features: a first heat
conductor layer for conducting a first heat transfer fluid; a
Peltier element layer which has a plurality of Peltier elements,
which are arranged spaced apart from one another and each comprise
a plurality of Peltier element conductors; and a second heat
conductor layer for conducting a second heat transfer fluid,
whereby the layers are arranged in the form of a stack, so that the
Peltier element layer is arranged between the first heat conductor
layer and the second heat conductor layer. During operation of the
temperature control device, the Peltier element layer can be
configured to cool the first heat conductor layer and to heat the
second heat conductor layer, or vice versa. Each Peltier element
can be made as a separate Peltier module. This means that each
Peltier element has its own electrical connections for supplying
and removing a current flowing through the Peltier element
conductors of the Peltier element. The Peltier elements can each
have a base plate on which solely the Peltier element conductors of
the particular Peltier element are arranged. A distance between
adjacent Peltier element conductors within a Peltier element can be
smaller than a distance between adjacent Peltier elements. The
Peltier elements can have both n-doped Peltier element conductors
and p-doped Peltier element conductors. The Peltier element
conductors can also be made as vapor-deposited conductive tracks or
as a textile.
[0030] The plurality of Peltier elements of a Peltier element layer
can cover a maximum of a tenth of the total area of the Peltier
element layer. A thermally insulating interspace can be located
between the Peltier elements. Alternatively, the plurality of
Peltier element conductors can cover a maximum of a tenth of the
total area of the Peltier element layer.
[0031] According to an embodiment, the temperature control device
can have an additional Peltier element layer, which has a plurality
of additional Peltier elements, which are arranged spaced apart
from one another and in each case comprise a plurality of
additional Peltier element conductors, and an additional first heat
conductor layer for conducting the first heat transfer fluid. In
this regard, the additional Peltier element layer can be arranged
in the stack between the second heat conductor layer and the
additional first heat conductor layer. In this way, no thermal
insulation is needed between adjacent layers.
[0032] Alternatively, the temperature control device can have a
thermal insulation layer, an additional first heat conductor layer
for conducting the first heat transfer fluid, and an additional
Peltier element layer, which has a plurality of additional Peltier
elements (600), which are arranged spaced apart from one another
and each comprise a plurality of additional Peltier element
conductors. In this regard, the thermal insulation layer can be
arranged in the stack adjacent to the second heat conductor layer
and the additional first heat conductor layer in the stack between
the thermal insulation layer and the additional Peltier element
layer.
[0033] According to an embodiment, a temperature control device has
a switching device, which is configured to conduct the first heat
transfer fluid in a first operating mode of the temperature control
device through the first heat conductor layer and the additional
first heat conductor layer and in a second operating mode of the
temperature control device either through the first heat conductor
layer or through the additional first heat conductor layer. The
temperature control element can be designed as a flap. The
temperature control device can achieve a higher heat output in the
first operating mode than in the second operating mode.
Advantageously, an electric current, which has an optimal current
strength for operating the Peltier element conductors, can flow
through active Peltier element conductors both in the first
operating mode and in the second operating mode.
[0034] According to an embodiment, adjacently arranged Peltier
element layers, for example, the first Peltier element layer and
the second Peltier element layer, can have a different number of
Peltier element conductors or Peltier elements. Alternatively or in
addition, an arrangement of Peltier element conductors or Peltier
elements on adjacently arranged Peltier elements layers can be
different. Alternatively or in addition, an extended area for the
Peltier element conductors or the Peltier elements on the
adjacently arranged Peltier element layers can be different. A
temperature distribution within the Peltier element layers can be
influenced by a suitable selection of the arrangement, number,
and/or size. A homogeneous temperature distribution in particular
can be achieved.
[0035] Further scope of applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus, are
not limitive of the present invention, and wherein:
[0037] FIG. 1 is a schematic diagram of a temperature control
device according to an exemplary embodiment of the present
invention;
[0038] FIG. 2 is a schematic diagram of a temperature control
device according to a further exemplary embodiment of the present
invention;
[0039] FIG. 3 is an enlarged illustration of a detail of the
temperature control device of FIG. 2;
[0040] FIG. 4 is a schematic diagram of a temperature control
device according to a further exemplary embodiment of the present
invention;
[0041] FIG. 5 is a schematic diagram of a series connection of a
plurality of temperature control devices according to a further
exemplary embodiment of the present invention;
[0042] FIG. 6 is a schematic diagram of a Peltier element of a
further exemplary embodiment of the present invention;
[0043] FIG. 7 is a schematic diagram of a Peltier element layer
according to an exemplary embodiment of the present invention;
[0044] FIG. 8 is a schematic diagram of a temperature control
device according to an exemplary embodiment of the present
invention;
[0045] FIG. 9 is an exploded diagram of a section of a temperature
control device according to an exemplary embodiment of the present
invention;
[0046] FIG. 10 is a schematic diagram of a Peltier element layer
and a Peltier element according to an exemplary embodiment of the
present invention; and
[0047] FIG. 11 is a projection of two Peltier element layers
according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION
[0048] In the following description of the exemplary embodiments of
the present invention, the same or similar reference characters are
used for elements with a similar action and shown in the various
drawings, whereby a repeated description of these elements is
omitted.
[0049] FIG. 1 shows a schematic diagram of a temperature control
device 100 according to an exemplary embodiment of the present
invention. Temperature control device 100 is formed here by a stack
of four temperature control elements 105. For the sake of clarity,
only one of temperature control devices 105 is provided with a
reference character. Temperature control device 100 can also have
more or fewer temperature control elements 105.
[0050] Each temperature control device 105 in FIG. 1 has a first
Peltier element layer 110, a second Peltier element layer 115, a
first heat conductor layer 120, a second heat conductor layer 125,
and an additional second heat conductor layer 130. According to the
illustration in FIG. 1, second heat conductor layer 125 forms the
base of the stack. On this layer, first Peltier element layer 110
is arranged, on which in turn first heat conductor layer 120 is
arranged. It is covered by second Peltier element layer 115, on
which finally there is the additional second heat conductor layer
130. According to the illustration in FIG. 1, first Peltier element
layer 110 and second Peltier element layer 115 each include three
individual spaced-apart, adjacently arranged Peltier element
conductors 135. For the sake of clarity, only one of the Peltier
element conductors 135 is provided with a reference character.
According to the illustration in FIG. 1, Peltier element conductors
135 in first Peltier element layer 110 are n-doped and Peltier
element conductors 135 in second Peltier element layer 115 are
p-doped.
[0051] In the exemplary embodiment of temperature control device
100 in FIG. 1, first heat conductor layer 120 is configured in each
case as a coolant channel. Second heat conductor layer 125 and
additional second heat conductor layer 130 are each made as a rib
element with two parallel bars and ribs arranged obliquely between
the bars. A galvanic insulation layer 140 is arranged between two
adjacent temperature control elements 105. For the sake of clarity,
only one of the galvanic insulation layers 140 is labeled with a
reference character. Optionally, one of the two bars of rib
elements 130 can also be omitted, for example, when two temperature
control elements 105 follow one another in the stack, so that a
second heat conductor layer 125 is adjacent to a temperature
control element 105, and is arranged separated perhaps only by a
galvanic insulation layer 140 from another second heat conductor
layer 130 of a following temperature control element 105. Here, for
example, in each case the bar adjacent to insulation layer 140 can
be omitted. Adjacent layers can be in direct contact to one
another.
[0052] According to the exemplary embodiment of temperature control
device 100 as shown in FIG. 1, each second heat conductor layer 125
has a first electrical contact 145 and additional second heat
conductor layer 130 a second electrical contact 150. To produce an
electrical series connection between temperature control elements
105 each time a second contact 150 of a temperature control element
105 is connected to a first contact 145 of an adjacent temperature
control element 105 via an electrical line 155. According to the
illustration in FIG. 1, first contact 145 of the topmost
temperature control element 105 in temperature control device 100
and second contact 150 of the lowest temperature control element
105 are connected to an electrical supply line or discharge line,
so that a current introduced by the supply line in temperature
control device 100 flows through the entire stack and can again
leave it through the discharge line.
[0053] Each heating unit or each temperature control element 105,
according to the illustration in FIG. 1, contains a coolant channel
120 and air passages 125, 130. Heat is transported over Peltier
elements 135 between the coolant and Peltier elements 135 and
between Peltier elements 135 and ribbed air side 125, 130. A design
principle that is simple to produce can be achieved by the
advantageous electrical interconnection 155. In addition, heating
unit 105 manages without electrical insulators, which generally
would negatively affect heat conduction properties in areas of high
required heat transfer.
[0054] Coolant flows through coolant channels 120. Peltier elements
135 are attached to these on both sides, so that heat transfer can
occur in both directions. The heat is transferred via Peltier
elements 135 and reaches the ribbed air side 125, 130, and ribs
125, 130 facilitate the heat transfer to the air. This heat path is
also made electrically continuously conductive, because the
electrically conductive heat conductor layers 120, 125, 130 are
made of metal, e.g., aluminum, and Peltier elements 135 contain
thermoelectrically active functional material. Electrical
insulation layer 140 is located in the middle between corrugated
ribs 125, 130. A possible heat transfer resistance by insulation
layer 140 plays no role, because according to the symmetry no heat
transfer occurs here in the vertical direction within the meaning
of the operating principle.
[0055] Peltier elements 135 in FIG. 1 are configured in a row
(layer) and are exclusively p- or n-doped. The electrical
interconnection 155 occurs in such a way that an enlargement of
temperature control device 100 in the vertical direction by an
increase in the number of layers of temperature control elements
105 brings about an increase in the total voltage drop at
temperature control device 100. In the exemplary embodiment shown
in FIG. 1, temperature control device 100 comprises four layers of
temperature control elements 105 each with an identical internal
structure. In contrast, a horizontal enlargement of temperature
control device 100 brings about a greater current strength, because
all elements in a layer are connected electrically in parallel.
[0056] According to the illustration in FIG. 1, the rib elements or
air sides 125, 130 of two adjacent vertical layers are connected by
a separate electrical conductor 155, which is symbolized as a
"cable" in the illustration, in such a way that the Peltier
elements 135, attached directly on an air side 125, 130, have a
different doping. The connection between two layers at Peltier
elements 135, which are attached to the same coolant channel 120,
need not be bridged by separate conductors, because coolant channel
120 itself is electrically conductive.
[0057] Depending on the construction, naturally also layers not
directly adjacent could be interconnected together, but adjacent
layers because of the shortest needed line length are obvious and
to be preferred. Likewise, a temperature control element layer 105
could be rotated 180.degree., so that the same doping does not
always lie on top and the other doping on the bottom. However, the
always invariable arrangement of the layers of temperature control
elements 105, as shown in FIG. 1, is useful for error prevention
during production. Electrical connections 145, 150 are attached as
shown in FIG. 1, so that they are integrated seamlessly into the
interconnection principle. As already described, the number of
layers of temperature control elements 105 defines the range of the
voltage drop at heating unit 100. If it were to be too high at a
given height of heating unit 100, the electrical interconnection
can be interrupted by additional electrical supply lines. According
to an exemplary embodiment, the heating unit section of FIG. 1 can
be replicated precisely and placed at the top on the existing
section. The separation would then be purely electrical, and the
mechanical attachment could be made similar to the connection
between the other layers. A too low voltage drop would more likely
be expected, however, for example, when the voltage made available
by a voltage source is to be tapped as completely as possible, for
instance, 12 V in a low-voltage on-board electrical system of the
vehicle. In this case, there is the possibility as well of an
expanded electrical series connection by an arrangement of a number
of such heating units 100 in a previously not utilized depth
dimension in a row, so that the free flow cross section on the air
side is retained. This aspect of the approach of the invention is
explained in conjunction with FIG. 5.
[0058] In summary for the exemplary embodiment of temperature
control device 100, as shown in FIG. 1, the current flow can again
be described as follows: The current flows through a row of Peltier
elements 135 with the same doping, in a parallel connection, to
cooling water channel 120 and through this channel to a row of
differently doped elements 135, which are also connected in series.
Via the air side 125, here a ribbing or a base plate with, e.g.,
ribs applied by soldering, there is an electrical connection 150 to
a separate conductor 155, of possible random design, which causes
the current flow in the ribbing or base plate 130 with, e.g., ribs,
applied by soldering, of another layer 105. Accordingly, the doping
changes in the electrical series connection of adjacent
elements.
[0059] FIG. 2 shows a schematic diagram of a temperature control
device 200 according to a further exemplary embodiment of the
present invention. Temperature control device 200 has a structure
that is virtually identical to temperature control device 100 of
FIG. 1, with the difference that each temperature control element
105 has an outer electrical connection 205 for bypassing coolant
channel 120. For the sake of clarity, only one of the electrical
connections 205 is provided with a reference character. The use of
electrical connections 205 is due to the fact that as a rule no
purely organic coolants are used, but those that contain a certain
amount of water. As a result, the coolant becomes electrically
conductive and would be exposed to a voltage difference during use
in a temperature control device according to FIG. 1. This can be
prevented by removing coolant channel 120 from the current cascade:
Accordingly, for example, a nonconductor is applied in a thin layer
to coolant tube 120, so that a heat transport resistance is as low
as possible. A preferably continuous conductive layer is in turn
applied to said layer. Coolant channel 120 itself thus remains
potential-free, but must be bypassed for this by the separate
conductor 205, as is the case on the air side 125, 130. Conductor
205 can also be designed differently than shown in FIG. 2.
[0060] FIG. 3 in a detail enlargement shows a structure of a
coolant channel 120 according to the exemplary embodiment shown in
FIG. 2. Shown is a section of coolant channel 120 in a longitudinal
section illustration. A galvanic insulation layer 305 made from an
insulator is applied to coolant channel 120, so that an electrical
voltage transmitted to a tube wall 310 cannot be transmitted to a
cooling fluid flowing through coolant tube 120. A conductor layer
315 made from an electrical conductor is applied over galvanic
insulation layer 305. Conductor layer 315 in turn has an electrical
contact to discharge line 320, which here can tap the electric
current and supply it to conductor layer 315 at another place, so
that the cooling fluid remains excluded from the electric current
flow. Tube wall 310 can be made, for example, of aluminum.
[0061] FIG. 4 in a schematic diagram shows an alternative exemplary
embodiment of a temperature control device 400. Temperature control
device 400 comprises a vertical stack of three temperature control
elements 405. These have a structure different from the temperature
control elements explained in conjunction with FIG. 1. Here, second
heat conductor layer 125 between first Peltier element layer 110
and second Peltier element layer 115 is also arranged next to first
heat conductor layer 120. A galvanic and thermal insulation layer
410 is located between first heat conductor layer 120 and second
heat conductor layer 125. The galvanic and thermal insulation layer
410 can have an optional bar for rib element 125 or rib element
130. The galvanic insulation layer, explained in regard to FIG. 1,
is omitted here. In the exemplary embodiment shown here,
temperature control element 405 has an additional first heat
conductor layer 415, which forms a base of temperature control
element 405. Here, first heat conductor layer 120 has first
electrical contact 145 and the additional first heat conductor
layer 415 second electrical contact 150. Further, second heat
conductor layer 125 of each temperature control element 405 is
connected via an electrical line 420 to additional second heat
conductor layer 130.
[0062] According to the illustration in FIG. 4, compared with the
exemplary embodiment explained in conjunction with FIG. 1, there is
only a one-sided heat transfer each on the cold and hot side. Thus,
insulation layer 410 on the other side now acts not just in an
electrically insulating manner against low voltage but also in a
thermally insulating manner. Accordingly, a thickness of insulation
layer 410 can be greater here. Air sides 125, 130 of adjacent
layers are connected electrically here via lines 420; likewise
cooling water sides 120, 415 of adjacent layers are no longer
connected directly electrically to one another, but analogous to
the air side also indirectly via separate conductors 425. This
occurs again in such a way that two electrically connected layers
120, 415 or 125, 130 have alternating dopings of Peltier stones 135
doped uniformly within a layer.
[0063] In regard to the exemplary embodiments explained with the
previous FIGS. 1 to 4, it is emphasized that, within the scope of
the approach presented here, an absolute sequence, i.e., a
beginning and end of a series connection with a specific doping (p
or n), and a number of Peltier elements in each spatial direction
basically remain open. Also open is an operation as a heat pump,
whereby air is heated, or as an air conditioning unit, whereby air
is cooled. The particular functionality can be changed by changing
the polarity.
[0064] FIG. 5 shows in a schematic diagram an exemplary embodiment
of an expanded electrical series connection 500 of temperature
control devices 100, 200, or 400 according to FIGS. 1 to 4 in a
horizontal direction. The plurality of temperature control devices
100, 200, or 400 is shown in simplified form. According to the
illustration in FIG. 5, temperature control devices 100, 200, or
400 are arranged in a plane one behind the other in a depth
direction 510 indicated by an arrow. According to structural
circumstances of the site of use, arrangement 500 shown here can
also be expanded with additional temperature control devices 100,
200, or 400. The individual temperature control devices 100, 200,
or 400 are connected together in an electrically conductive manner,
so that a current flow can occur through the entire arrangement
500. The electrical connections are not shown in FIG. 5. Another
arrow represents a flow direction 520 of a heat transfer fluid
carried, for example, through the second and additional second heat
conductor layers of temperature control devices 100, 200, or 400.
This can be air, for example.
[0065] Alternatively to the exemplary embodiments of temperature
control devices 100, 200, 400, as presented according to FIGS. 1 to
4, a further exemplary embodiment of a temperature control device
of the invention can have a Peltier element layer, which has a
plurality of Peltier elements, which in turn have a plurality of
Peltier element conductors. Thus, instead of pure n- or p-doped
elements 135 externally geometrically identical elements can be
used, which intrinsically have any desired planar fine structure of
n- and p-series connected components.
[0066] FIG. 6 shows a schematic diagram of such a Peltier element
600. Shown is a horizontal arrangement of Peltier element
conductors 135. In this regard, in each case an n-doped Peltier
element conductor and a p-doped Peltier element conductor are
arranged alternately in a plane. Adjacently arranged and
differently doped Peltier element conductors 135 are each connected
to one another alternately via an electrical conductor 605 on a hot
side and an additional electrical conductor 605 on a cold side.
There are gaps 610 in the electrical conductors 605 on a hot side
or cold side opposite to the particular electrical conductors. An
electrical insulator 615 is arranged in each case above and below
the layer of Peltier element conductors 135.
[0067] An exemplary embodiment of a temperature control device of
the invention can be built according to the principle of
temperature control devices 100, 200, 400 shown in the FIGS. 1 to
4, whereby, however, Peltier elements 600 are used. So that an
electric current flow through the entire stack of a temperature
control device built in such a way is assured, in contrast to the
shown exemplary embodiments 100, 200, 400, here each Peltier
element 600 has a supply line and discharge line for the electric
current. In contrast to the exemplary embodiments according to
FIGS. 1 to 4, the electric current here flows not vertically but
horizontally through the particular Peltier element 600. Possible
is either a serial interconnection between individual Peltier
elements 600 or a parallel connection, in which each Peltier
element 600 is connected to a central current supply of the
vehicle, generally the car battery, so that a voltage drop of 12 V
across the entire stack of the temperature control device is
assured.
[0068] According to an embodiment, in which Peltier elements 600
are used, a current flow occurs not through the entire stack, and
particularly not through the heat conductor layers, but solely
through the Peltier element layers. The individual Peltier element
layers can each be connected parallel or serially.
[0069] Depending on the voltage drop at Peltier elements 600, it
would be possible to also use the electrical interconnection
described here between the rows to increase further the total
voltage drop across the heating unit. Alternatively, simply each
row with thermoelectric elements 600 can be treated separately as a
single circuit, when, e.g., the fine structure of Peltier module
600 already causes a voltage drop of 12 V, which corresponds to the
conventional functionality. For example, an n- or p-component or n-
or p-Peltier element conductor can have a voltage drop of 0.0625 V.
With 16 components, this would result in 1 V for a Peltier element.
If heating unit 12 has serially connected rows, a 12 V voltage drop
would be realized overall.
[0070] FIG. 7 shows a perspective view of a planar layer,
particularly a Peltier element layer 710, according to an exemplary
embodiment of the present invention. Peltier element layer 710 has
a plurality of Peltier elements 600. Peltier elements 600 can each
be a module, as is shown, for example, in FIG. 6. The individual
Peltier elements 600 are each separated from one another by a
thermally insulated interspace 712. A heat flow direction is
indicated by an arrow.
[0071] FIG. 8 shows a schematic illustration of a temperature
control device 800, according to an exemplary embodiment of the
present invention. The temperature control device has a stack of
heat conductor layers, of which by way of example an air channel is
labeled with reference character 125, and Peltier element layers,
of which by way of example one is labeled with reference character
710. According to this exemplary embodiment, warm air flows as
indicated by the arrow into temperature control device 800 and cold
air out of temperature control device 800. This means that the
Peltier elements are arranged or operated so that air channels 125
are cooled. In contrast, additional heat conductor layers of
temperature control device 800, through which, for example, a
coolant can flow, are heated.
[0072] FIG. 9 on the left shows a layer of the temperature control
device shown in FIG. 8 and on the right an exploded view of this
layer, according to an exemplary embodiment of the present
invention. Shown is a stack-shaped structure of a first heat
conductor layer 120, two second heat conductor layers 125, and two
Peltier element layers 710. Peltier element layers 710 are each
arranged between first heat conductor layer 120 and one of the
second heat conductor layers 125. First heat conductor layer 120 is
designed in the form of a flat coolant channel, through which a
coolant 950 flows. Peltier element layers 710 can be configured as
Peltier layers with electrical contacting and bonded electrical
insulation.
[0073] FIG. 10 shows a Peltier element layer 710 and a detailed
Peltier element 600, according to an exemplary embodiment of the
present invention. Peltier element layer 710 can be the Peltier
layer used in FIG. 9.
[0074] An occupancy rate .epsilon. can be less than or equal to
10%:
.epsilon.=(sum of the areas of the Peltier elements 600)/(area of
layer 710)=<10%
[0075] Peltier element 600 has a base plate and a cover plate,
between which a plurality of Peltier element conductors is
arranged. The Peltier element conductors can be arranged according
to the arrangement shown in FIG. 6.
[0076] According to the exemplary embodiment shown in FIG. 10,
instead of doped stones entire elements 600 are placed in a layer
710. In this regard, at most 10% of the area of a layer 710 is
occupied by Peltier elements 600. Thus, the integration level can
no longer be in the doped P and N stones, but entire purchased
elements can be used, which have a particular fine structure, i.e.,
P and N. The fine structure can have stones. Instead of
interconnected stones, for example, vapor-deposited conductive
tracks or textile can be used.
[0077] According to an exemplary embodiment, the approach of the
invention can be used in a thermoelectric heating and
air-conditioning device. A device with a modular structure is used
for heating or cooling the internal compartment air. The heat
absorption or heat dissipation occurs via the low-temperature
circuit of the vehicle, preferably an electric vehicle. In order to
be economical with commercially available thermoelectric materials,
the basic design of the device is conceived for the best possible
heat transfer.
[0078] In the electric vehicle, heating of the passenger area
represents a challenge, because no notable engine waste heat is
available. Electrical resistance heaters convert the current stored
in the battery with a COP=1 (coefficient of performance) into heat
and reduce the cruising range significantly. More efficient are
heat pumps that operate with a COP>1 and recover heat in part
from current, in part also from the environment or from waste heat
sources with low temperature levels. Apart from the use of
coolant-heat pumps, thermoelectric materials are also suitable
which could produce the effect without moving parts and without
coolant. An ideal situation would be when the cooling function for
the passenger area (summer operation) could be realized by means of
the same thermoelectric elements, because then the cooling circuit
would be completely eliminated and the switching between heating
and cooling would be accomplished by changing the polarity of the
applied voltage without mechanical changes.
[0079] The approach of the invention makes it possible to
accomplish the function "heating of the passenger area" with a
COP>1 (heat pump operation) and to eliminate the separate
cooling circuit by electrical switching to the cooling operation,
whereby the COP in the cooling operation should not be inferior to
the COP of a cooling circuit.
[0080] The essential feature of a heating and air-conditioning
device with utilization of the Peltier effect is a considerably
increased heat transfer with the lowest possible temperature
differences between fluid and the thermally connected side of the
thermoelectric elements. Because the efficiency of heat exchangers
rapidly reaches its limits, the solution remains to bring about
small driving temperature differences by a significant reduction of
the transferred heat flux density. The association between
decreasing COPs at greater temperature differences is much more
greatly pronounced in thermoelectrics than in cooling circuits,
because undesirable heat conduction in a natural heat flow
direction occurs between the warmer and cooler side of a Peltier
element. A few Kelvin in the cooling operation can already
constitute the difference between an acceptable use and a no longer
economic or even a physically no longer possible configuration,
because the following feedback mechanism is present: Rather poor
COPs cause a greater amount of heat on the waste heat side and
increase the temperature there, which in turn worsens the COP and
further increases the power requirement and heat amount on the
waste heat side.
[0081] During the reduction of the power density, one cannot simply
reduce the supplying of current to the thermoelectric element,
because here the COP would worsen severely, and the elements remain
as undesirable thermal bridges between the hot and cold side. The
employed semiconductors usually have thermal conductivities in the
single-digit range (W/m2K). Instead, the Peltier elements must be
supplied with an optimal current strength to be calculated or as a
characteristic diagram to be provided, and for reducing the power
density may only occupy a small portion of the area of their
particular integration-surface layer. The portions of the area not
occupied by the thermoelectric material are to be filled, for
example, with insulation material, with air, or with gas, as is
shown in FIG. 7.
[0082] The low power density based on a surface layer of Peltier
elements must be compensated in the remaining dimension by
successive layers as close as possible, so that overall an
acceptable volumetric power density is available and the
combination heating/cooling device is not built too large, as is
shown in FIG. 8. The air channels are naturally ribbed, even if no
ribs are shown in FIG. 8.
[0083] The desired advantages and effects can be amplified by
countercurrent flow of the passenger area air and coolant, as is
shown in FIG. 8, and by material connection of the individual
layers, as is shown in FIG. 9. Thus, for instance, a bonding
application of a very thin electrical insulation layer to the
conductor layer can occur. Ideally, in every layer toward each
side, successive layers are connected by material bonding and made
only as thick as absolutely necessary to fulfill their task:
Peltier element->electrical conductor->electrical
insulator->bottom of the flow channel (coolant or air side). As
illustrated in FIG. 9, coolant channel 120, which can be provided
with baffles, turbulators, and the like, is attached thermally on
both sides to thermoelectric elements. A further advantage of this
configuration is the modular structure and the possibility provided
thereby by suitable adjustment of the number of layers and choice
of the planar dimensions to develop decentralized components, which
can be placed close to the particular outlet openings in the front
or rear area.
[0084] During cold operation with a 1200 W cooling capacity,
15.degree. C. exhaust temperature, 35.degree. C. coolant
temperature, dimensions of 150.times.150.times.300 mm.sup.3, 10
coolant layers, realistic air and coolant flows, and suitable
thermoelectric material, a=>COP=Q.sub.cold/P.sub.electric=2 can
be realized.
[0085] The heating and cooling unit is designed so that the maximum
COP at one or more relevant operating points can be approximated as
closely as possible. At a lower power requirement, therefore a
reduced current supply, the COP would worsen, because the Peltier
elements act increasingly as a natural thermal bridge. Therefore,
after values fall below a certain power level, individual layers
are separated not only electrically, but also thermally from the
air stream in that, e.g., flaps close the inlet. This possibility
can be realized for a certain number of individual layers, or also
overlapping for a number of layers. A finer gradation improves the
COP over the operating cycle, and a rougher gradation reduces the
cost of production.
[0086] For example, 12 layers can be provided in a heating and
cooling unit. Of these, in the case of a total of 6 layers, 3
layers each can be closed jointly on the air side. Thus, 2 flaps
are needed. The number of simultaneously passed-through layers can
therefore assume the following values: 6 layers if two flaps are
closed, 9 layers if one flap is closed, and 12 layers if all flaps
are open.
[0087] Further, the component is to be dimensioned so that during
heat-up or cool-down, i.e., during heating and cooling, the
required heating or cooling performance can be achieved,
independent of the COP achieved in these phases.
[0088] FIG. 11 shows a vertical projection of two adjacent Peltier
element layers in a view plane, according to an exemplary
embodiment of the present invention. Shown is a front Peltier
element layer, the top layer in FIG. 11, with a plurality of
schematically shown Peltier elements 600. For the sake of clarity,
only one of the plurality of Peltier elements 600 is provided a
reference character 600. Further, a back Peltier element layer is
shown with a plurality of schematically shown Peltier elements
1600. Peltier elements 1600 are shown by broken lines. For the sake
of clarity, only one of the plurality of Peltier elements 1600 is
again provided with a reference character 1600.
[0089] According to this exemplary embodiment, the front Peltier
element layer and the back Peltier element layer have a different
number of Peltier elements 600, 1600. By way of example, the front
Peltier element layer has 16 Peltier elements 600 and the back
Peltier element layer 9 Peltier elements 1600. Moreover, Peltier
elements 600 have a different arrangement on the front Peltier
element layer than Peltier elements 1600 on the back Peltier
element layer. Shown is a staggered arrangement in which a row or
column with Peltier elements 600 alternates with a row or column
with Peltier elements 1600. In this regard, Peltier elements 600
have no overlapping areas relative to Peltier elements 1600.
According to this exemplary embodiment, Peltier elements 600 and
Peltier elements 1600 each have the same size. Peltier elements
600, 1600 can be identical. Alternatively, Peltier elements 600,
1600 can be different in size.
[0090] Ideally, in each case a surface of a Peltier element layer
has a homogeneous temperature distribution. In reality, however,
corresponding temperature maxima or temperature minima, so-called
hot spots and cold spots, develop at Peltier elements 600, 1600,
which represent heat sources or heat sinks. This is caused by the
fact that the horizontal heat conduction is limited. The planar
arrangement and number of Peltier elements 600, 1600 and in
addition or alternatively, the element size of Peltier elements
600, 1600 can vary between two adjacent Peltier element layers.
This can result in the advantage of reducing the formation of hot
spots or cold spots, in that the heat sources or heat sinks, which,
for example, act on a ribbing, turbulators, or a fluid, in the
conceptual vertical projection, shown in FIG. 11, of both Peltier
element layers on a projection area increase in number and have
smaller distances.
[0091] The described exemplary embodiments have been selected only
by way of example and can be combined with one another.
Particularly, a combination of the exemplary embodiments with
Peltier element layers made up of individual Peltier element
conductors and the exemplary embodiments with Peltier element
layers made up of Peltier elements is possible. In this regard, the
electrical interconnection of the Peltier element layers can be
adjusted accordingly.
[0092] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are to be included within the scope of the following
claims.
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