U.S. patent application number 15/319533 was filed with the patent office on 2017-05-11 for thermoelectrically cooled or heated container.
This patent application is currently assigned to Liebherr-Hausgerate Lienz GmbH. The applicant listed for this patent is Liebherr-Hausgerate Lienz GmbH, Liebherr-Hausgerate Ochsenhausen GmbH. Invention is credited to Michael FREITAG, Jochen HIEMEYER, Martin KERSTNER.
Application Number | 20170131001 15/319533 |
Document ID | / |
Family ID | 54706798 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170131001 |
Kind Code |
A1 |
HIEMEYER; Jochen ; et
al. |
May 11, 2017 |
THERMOELECTRICALLY COOLED OR HEATED CONTAINER
Abstract
The present invention relates to a thermoelectrically cooled or
heated container, in particular a refrigerator unit and/or a
freezer unit, having at least one cooled or heated inner space and
having at least one thermoelectric element, in particular having at
least one Peltier element, for generating cold or heat in the inner
space, wherein the thermoelectric element is arranged between two
thermoconductive solid bodies of which one or both have an
increasing cross-sectional area as the spacing from the
thermoelectric element increases.
Inventors: |
HIEMEYER; Jochen;
(Karlstadt, DE) ; KERSTNER; Martin; (Wurzburg,
DE) ; FREITAG; Michael; (Wurzburg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liebherr-Hausgerate Lienz GmbH
Liebherr-Hausgerate Ochsenhausen GmbH |
Lienz
Ochsenhausen |
|
AT
DE |
|
|
Assignee: |
Liebherr-Hausgerate Lienz
GmbH
Lienz
AT
Liebherr-Hausgerate Ochsenhausen GmbH
Ochsenhausen
DE
|
Family ID: |
54706798 |
Appl. No.: |
15/319533 |
Filed: |
June 12, 2015 |
PCT Filed: |
June 12, 2015 |
PCT NO: |
PCT/EP2015/001194 |
371 Date: |
December 16, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25D 31/005 20130101;
F25D 2201/14 20130101; F25B 21/02 20130101; F25B 2321/025 20130101;
F25B 2321/023 20130101; F25B 2500/11 20130101; F25B 21/04
20130101 |
International
Class: |
F25B 21/04 20060101
F25B021/04; F25D 31/00 20060101 F25D031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 16, 2014 |
DE |
10 2014 008 668.2 |
Jan 20, 2015 |
DE |
10 2015 000 553.7 |
May 20, 2015 |
DE |
10 2015 006 557.2 |
Claims
1. A thermoelectrically cooled or heated container, in particular a
refrigerator unit and/or a freezer unit, having at least one cooled
or heated inner space and having at least one thermoelectric
element, in particular having at least one Peltier element, for
generating cold or heat in the inner space, characterized in that
the thermoelectric element is arranged between two thermoconductive
solid bodies of which one or both have an increasing
cross-sectional area as the spacing from the thermoelectric element
increases.
2. A container in accordance with claim 1, characterized in that
the thermoelectric element is received between the two
thermoconductive solid bodies such that forces acting on the solid
body or bodies are not transferred or are only transferred to a
reduced degree onto the thermoelectric element.
3. A container in accordance with claim 1, characterized in that
the thermoelectric element is clamped between the solid bodies;
and/or in that the thermoelectric element is mechanically fixedly
clamped to the solid bodies.
4. A container in accordance with claim 1, characterized in that
one of the solid bodies is thermoconductively connected to the
outer skin of the unit and one of the solid bodies is
thermoconductively connected to the inner wall of the unit.
5. A container in accordance with claim 1, characterized in that
the container has a vacuum insulation or another insulation as the
thermal insulation of the inner space that completely or partly
surrounds the cooled inner space, with provision preferably being
made that the thermoelectric element and/or one or both of the two
solid bodies are arranged in the insulation layer.
6. A container in accordance with claim 5, characterized in that a
heat insulation which consists in total or regionally of a full
vacuum system is arranged between an inner wall bounding the inner
space and an outer skin of the container.
7. A container in accordance with claim 1, characterized in that
the two solid bodies are connected, and preferably clamped, to one
another by one or more connection means, with the connection means
preferably having a smaller thermal conductivity than the solid
bodies, with provision preferably being made that the connection
means consist of plastic or comprise plastic.
8. A container in accordance with claim 7, characterized in that
the single connection means or plurality of connection means
fixes/fix the spacing of the solid bodies.
9. A container in accordance with claim 7, characterized in that
the single connection means or plurality of connection means is/are
arranged at a spacing from the thermoelectric element which is as
large as possible; and/or in that in the case of a plurality of
connection means they have the same spacing from the thermoelectric
element.
10. A container in accordance with claim 7, characterized in that
the spacing of the single connection means or plurality of
connection means from the thermoelectric element is larger than the
edge length of the thermoelectric element.
11. A container in accordance with claim 1, characterized in that
the solid bodies consist of metal and preferably of aluminum or
comprise it.
Description
[0001] The present invention relates to a thermoelectrically cooled
or heated container, in particular to a refrigerator unit and/or a
freezer unit, having at least one cooled or heated inner space and
having at least one thermoelectric element, in particular having at
least one Peltier element that is arranged such that is generates
cold or heat in the inner space.
[0002] In a thermoelectric refrigerator unit or freezer unit, the
heat transfer from the refrigerated inner side to the
thermoelectric element and from the thermoelectric element to the
outside of the unit can be based solely on solid body thermal
conduction. Solid bodies are used for this purpose that are in
thermoconductive connection with the thermoelectric element. With
such a unit, the heat transfer from the solid bodies to the
thermoelectric element is of great importance. If a defect in the
contact occurs, it may result in a temperature drop at the border
surface and thus in an inefficient generation of cold or heat. A
fixed interconnection between the thermoelectric element and the
solid body, e.g. via a thermoconductive adhesive, is
advantageous.
[0003] Provision is furthermore made in a preferred embodiment that
a thin graphite film is arranged at one side as a coupling element
for the mechanical relief of the thermoelectric element in the
production process, with the thermoelectric element being fixed by
clamping between the two solid bodies via connection elements
described in more detail in the following. At the other side, the
thermoconductive adhesive is also used to compensate production
tolerances in the thicknesses of the thermoelectric element, the
solid bodies and the connection elements. The graphite film is
preferably used at the hot side since the higher heat flows flow
here and the heat transfer resistance through the thin graphite
film is typically smaller than that through the thermoconductive
adhesive layer somewhat thicker due to tolerance compensation.
[0004] A further special feature is that material transitions in
the heat exchanger, i.e. in the solid body, are avoided as much as
possible since they result in additional heat transfer resistances.
In the ideal case, the heat exchanger, i.e. one of the solid bodies
that can comprise aluminum, for example, and that is connected to
the thermoelectric element represents the outer skin of the unit.
This produces a technical production challenge in the contacting of
the thermoelectric element.
[0005] In addition, there is a rigid connection between the inner
container and the outer skin via the thermoelectric element.
[0006] If thermal strains occur in operation or also in the
manufacture of the container, this can produce a mechanical strain
and possibly a breakage of the thermoelectric element.
[0007] These considerations are by no means restricted to
refrigerator units and/or freezer units, but also apply to
thermally insulated containers in general.
[0008] The thermally insulated container has at least one
temperature-controlled inner space, with this being able to be
cooled or heated so that a temperature results in the inner space
below or above the ambient temperature of e.g. 21.degree. C.
[0009] It is the underlying object of the present invention to
further develop a container of the initially named type such that
the mechanical strain of the thermoelectric element is kept as
small as possible and simultaneously a good thermal transport is
ensured.
[0010] This object is achieved by a container having the features
of claim 1. Provision is accordingly made that the thermoelectric
element is arranged or received between at least two
thermoconductive solid bodies of which one or both has/have an
increasing cross-sectional area as the distance from the
thermoelectric element increases.
[0011] The at least two solid bodies with good thermal conductivity
are in thermoconductive contact with the thermoelectric element
such that, in operation of the thermoelectric element, one of the
solid bodies represents the cold side and the other solid body
represents the hot side in operation of the thermoelectric
element.
[0012] The at least two thermoconductive solid bodies form a
primary heat exchanger which is connected to the thermoelectric
element such that one of the solid bodies forms the cold side and
one of the solid bodies forms the hot side in operation of the
thermoelectric element.
[0013] This primary heat exchanger is preferably thermoconductively
connected to at least one secondary heat exchanger. The secondary
heat exchanger comprises at least one solid body and preferably two
solid bodies. These solid bodies of the secondary heat exchanger
can e.g. form the inner container, i.e. the wall, of the cooled or
heated inner space and/or the outer skin of the container.
[0014] The solid bodies of the primary solid body and/or of the
secondary solid body preferably consist of metal or comprise metal.
Aluminum can be considered, for example.
[0015] The reception of the thermoelectric element in the primary
heat exchanger that is formed by the at least two solid bodies
protects it from excessive mechanical strains.
[0016] The primary heat exchanger that comprises the solid bodies
between which the thermoelectric element is arranged has a very
good thermal coupling of the generated cold and of the waste heat
and brings the heat flow to a comparatively large surface due to
its increasing cross-sectional area, which brings along the
advantage that on a further coupling to further solid bodies such
as to the above-named secondary heat exchanger a heat loss occurs
which is as small as possible.
[0017] Provision is preferably made that the thermoelectric element
is received between the two thermoconductive solid bodies such that
forces acting on the solid body or bodies are not transferred or
are only transferred to a reduced degree onto the thermoelectric
element.
[0018] Provision is made in accordance with a preferred embodiment
that the thermoelectric element is clamped between the solid bodies
which form the primary heat exchanger. Provision is preferably made
in this respect that the connection element or elements which
connects/connect the solid bodies has/have a small thermal
conductivity so that no significant heat bridge is produced.
[0019] In this respect, the clamping or the connection between the
solid bodies is thus preferably made in that the heat bridge is as
low as possible due to the connection means which connect the solid
bodies.
[0020] It can generally be a single connection means or also two or
more connection means.
[0021] It is conceivable to clamp the two solid bodies to one
another, i.e. to pull the solid bodies together such that the
connection means are tensioned.
[0022] In an embodiment, the connection means is a spacer. It is
conceivable that the connection means is designed such that it is
subjected to one or more of tension, compression, torsion and
shear.
[0023] Provision is made in a further embodiment of the invention
that one of the solid bodies is thermoconductively connected to the
outer skin of the unit and one of the solid bodies is
thermoconductively connected to the inner wall of the unit. This
connection can be direct or indirect, with a direct connection
being preferred.
[0024] Provision is made in a further embodiment of the invention
that the container has a vacuum insulation as the thermal
insulation of the inner space that surrounds the cooled inner space
completely or partly. Another insulation such as a foaming is also
conceivable.
[0025] The primary heat exchanger and/or the thermoelectric element
is/are preferably located in the insulation layer which is located
between the inner wall and the outer wall of the container.
[0026] The thermal insulation is located between the outer skin and
the inner container of the unit and/or between the inner wall and
the outer wall of a closing element such as a door, a lid or a
flap, drawer, etc. The thermal insulation can e.g. have one or more
vacuum insulation panels. It is also conceivable to use one or more
enveloping bodies composed of a vacuum-tight envelope and in
particular of a high barrier film which are filled with a support
material such as Pearlite for thermal insulation. The enveloping
bodies are closed structures in which there is a vacuum.
[0027] An embodiment is particularly preferred in which a thermal
insulation is arranged between the inner wall bounding the inner
space and the outer skin and comprises a full vacuum system. A
thermal insulation is to be understood by this which comprises only
or primarily an evacuated region which is filled with a support
material. The bounding of this region can be formed, for example,
by a vacuum-tight film and preferably by a high barrier film. Only
such a film body can thus be present between the inner wall of the
container, preferably of the unit, and the outer skin of the
container, preferably of the unit, as the thermal insulation which
has a region which is surrounded by a vacuum-tight film, in which
there is a vacuum and in which a support material is arranged. A
foaming and/or vacuum insulation panels is/are preferably not
provided as thermal insulation or another thermal insulation is not
provided, except for the full vacuum system between the inner side
and the outer side of the container or unit.
[0028] This preferred form of thermal insulation in the form of a
full vacuum system can extend between the wall bounding the inner
space and the outer skin of the carcass and/or between the inner
side and the outer side of the closing element such as a door,
flap, lid, or the like.
[0029] The full vacuum system can be obtained such that an envelope
of a gas-tight film is filled with a support material and is
subsequently sealed in a vacuum-tight manner. In an embodiment,
both the filling and the vacuum-tight sealing of the envelope take
place at normal or ambient pressure. The evacuation then takes
place by the connection to a vacuum pump of a suitable interface
worked into the envelope, for example an evacuation stub which can
have a valve. Normal or ambient pressure is preferably present
outside the envelope during the evacuation. In this embodiment, it
is preferably not necessary at any time of the manufacture to
introduce the envelope into a vacuum chamber. A vacuum chamber can
be dispensed with in an embodiment to this extent during the
manufacture of the vacuum insulation.
[0030] A vacuum-tight or diffusion-tight envelope or a vacuum-tight
or diffusion-tight connection or the term high barrier film is
preferably understood as an envelope or as a connection or as a
film by means of which the gas input into the vacuum insulation
body is reduced so much that the increase in the thermal
conductivity of the vacuum insulation body caused by gas input is
sufficiently low over its service life. A time period of 15 years,
preferably of 20 years, and particularly preferably of 30 years, is
to be considered as the service life, for example. The increase in
the thermal conductivity of the vacuum insulation body caused by
gas input is preferably <100%, and particularly preferably
<50%, over its service life.
[0031] The surface-specific gas permeation rate of the envelope or
of the connection or of the high barrier film is preferably
<10-5 mbar*I/s*m.sup.2 and particularly preferably <10-6
mbar*I/s*m.sup.2 (measured according to ASTM D-3985). This gas
permeation rate applies to nitrogen and to oxygen. There are
likewise low gas permeation rates for other types of gas (in
particular steam), preferably in the range from <10-2
mbar*I/s*m.sup.2 and particularly preferably in the range from
<10-3 mbar*I/s*m.sup.2 (measured according to ASTM F-1249-90).
The aforesaid small increases in the thermal conductivity are
preferably achieved by these small gas permeation rates.
[0032] An enveloping system known from the sector of vacuum panels
are so-called high barrier films. Single-layer or multilayer films
(which are preferably able to be sealed) having one or more barrier
layers (typically metal layers or oxide layers, with aluminum and
an aluminum oxide preferably being used as the metal or oxide
respectively) are preferably understood by this within the
framework of the present invention which satisfy the above-named
demands (increase in thermal conductivity and/or surface-specific
gas permeation rate) as a barrier to the gas input.
[0033] The above-named values or the make-up of the high barrier
film are exemplary, preferred values which do not restrict the
invention.
[0034] Provision is preferably made that the thermoelectric element
is mechanically fixedly clamped to the solid bodies.
[0035] Provision is preferably made that the one connection means
or the plurality of connection means clamps/clamp the at least two
thermoconductive solid bodies via a clamping connection.
[0036] To keep the thermal conduction through the connection means
of the solid bodies as small as possible, provision can be made
that the two solid bodies are connected, and preferably clamped, to
one another by connection means, with the connection means having a
smaller thermal conductivity than the solid bodies.
[0037] The connection means preferably comprise a different
material than the solid bodies which form the primary heat
exchanger and/or the secondary heat exchanger.
[0038] It is conceivable that the connection means consist of
plastic or comprise plastic. Polyamide or also another plastic can
be considered, for example.
[0039] Provision is made in a further preferred embodiment of the
invention that the connection means fix the spacing of the
thermoconductive solid bodies from one another.
[0040] As stated above, a preferred embodiment of the invention
comprises the solid bodies consisting of metal, and preferably of
aluminum, or comprising it.
[0041] The single connection means or the plurality of connection
means can be arranged at a spacing from the thermoelectric element
which is as large as possible. Since the most critical strains are
deformations at the total unit or container that are led off onto
the thermoelectric element via the rigid primary heat exchanger as
a lever, a stabilization at all sides as far as possible outside
the thermoelectric element is of advantage.
[0042] The spacing of the connection means from the thermoelectric
element is preferably larger than the edge length of the
thermoelectric element.
[0043] Further details and advantages of the invention will be
explained in more detail with reference to an embodiment shown in
the drawing.
[0044] The only FIGURE shows a perspective view of a primary heat
exchanger having a thermoelectric element arranged therein. It can
be configured as a Peltier element.
[0045] The thermoelectric element is clamped between two solid
bodies 10, 12 of good thermoconduction, with the solid body 10
reducing in cross-section when passing across the insulation plane
from left to right in accordance with the FIGURE and with the solid
body 12 increasing in cross-section when passing across the
insulation plane from left to right in accordance with the
FIGURE.
[0046] The thermoelectric element is located between the two solid
bodies. The solid bodies can be arranged with specular symmetry
relative to an axis extending through the thermoelectric
element.
[0047] The two solid bodies form a primary heat exchanger. It is
preferably thermoconductively connected to at least one secondary
solid body or heat exchanger via the outwardly disposed surfaces
10' and 12' of the solid bodies 10, 12 that are preferably planar.
The secondary heat exchanger is preferably arranged directly at the
surfaces 10' and 12'.
[0048] The secondary heat exchanger can have two or more solid
bodies that form the outer skin of the container, on the one hand,
and the inner wall of the container, on the other hand, or can be
connected thereto, for example. The inner wall bounds the heated or
cooled inner space of the container in accordance with the
invention.
[0049] The term "container" is to be understood generally and
comprises every arrangement that has at least one inner space that
is heated or cooled. In a preferred embodiment of the invention, a
"container" is understood as a refrigerator unit and/or a freezer
unit. This unit preferably does not have any conventional
refrigerant circuit, but rather only has the Peltier element or
another thermoelectric element as the heat source or for cold
generation.
[0050] The temperature-controlled inner space is either cooled or
heated depending on the type of the unit (cooling appliance,
heating cabinet, etc.)
[0051] Provision is made in an embodiment that the container in
accordance with the invention is a refrigerator unit and/or a
freezer unit, in particular a domestic appliance or a commercial
refrigerator. Such units are, for example, covered which are
designed for a stationary arrangement at a home, in a hotel room,
in a commercial kitchen or in a bar. It can, for example, be a wine
cooler. Chest refrigerators and/or freezers are furthermore also
covered by the invention. The units in accordance with the
invention can have an interface for connection to a power supply,
in particular to a domestic mains supply (e.g. a plug) and/or can
have a standing aid or installation aid such as adjustment feet or
an interface for fixing within a furniture niche. The unit can, for
example, be a built-in unit or also a stand-alone unit.
[0052] In an embodiment, the container or the unit is configured
such that it can be operated at an AC voltage such as a domestic
mains voltage of e.g. 120 V and 60 Hz or of 230 V and 50 Hz. In an
alternative embodiment, the container or the unit is configured
such that it can be operated with DC current of a voltage of, for
example, 5 V, 12 V or 24 V. Provision can be made in this
embodiment that a plug-in power supply is provided inside or
outside the unit via which the unit is operated. An advantage of
the use of thermoelectric heat pumps in this embodiment is that the
whole EMC problem only occurs at the power pack.
[0053] Provision can in particular be made that the refrigerator
unit and/or freezer unit has a cabinet-type design and has a useful
space which is accessible to a user at its front side (at the upper
side in the case of a chest). The useful space can be divided into
a plurality of compartments which are all operated at the same
temperature or at different temperatures. Alternatively, only one
compartment can be provided. Storage aids such as trays, drawers or
bottle-holders (also dividers in the case of a chest) can also be
provided within the useful space or within a compartment to ensure
an ideal storage of refrigerated goods or frozen goods and an ideal
use of the space.
[0054] The useful space can be closed by at least one door
pivotable about a vertical axis. In the case of a chest, a lid
pivotable about a horizontal axis or a sliding cover is conceivable
as the closing element. The door or another closing element can be
connected in a substantially airtight manner to the carcass by a
peripheral magnetic seal in the closed state. The door or another
closing element is preferably also thermally insulated, with the
thermal insulation being able to be achieved by a foaming and
optionally by vacuum insulation panels or also preferably by a
vacuum system and particularly preferably by a full vacuum system.
Door storage areas can optionally be provided at the inside of the
door in order also to be able to store refrigerated goods
there.
[0055] It can be a small appliance in an embodiment. In such units,
the useful space defined by the inner wall of the container has,
for example, a volume of less than 0.5 m.sup.3, less than 0.4
m.sup.3 or less than 0.3 m.sup.3.
[0056] The outer dimensions of the container or unit are preferably
in the range up to 1 m with respect to the height, width and
depth.
[0057] The invention is, however, not restricted to refrigerator
units and/or freezer units, but rather generally applies to units
having a temperature-controlled inner space, for example also to
heat cabinets or heat chests.
[0058] In the case of a container or unit having a heated inner
space, a thermal conduction takes place from the environment or
from the outer skin of the container by means of the solid body to
the thermoelectric element and from it by means of a solid body
through heat conduction to the inner space or to the inner wall of
the container bounding the inner space.
[0059] The solid bodies 10, 12 preferably comprise aluminum.
[0060] Connection elements are marked by reference numeral 20 that
fixedly mechanically clamp the at least one thermoelectric element
to the thermoconductive solid bodies 10, 12.
[0061] The clamping preferably takes place by a clamp connection.
The element with little thermal conductivity or the connection
element or elements 20 clamps/clamp the two solid bodies 10, 12 via
a clamp connection.
[0062] The connection elements 2 form a non-thermoconductive
fastening or a fastening with little thermal conductivity of the
two solid bodies 10, 12 to one another. The connection elements 20
fix the spacing of the solid bodies 10, 12 from one another.
[0063] The spacing of the connection elements 20 from the
thermoelectric element is selected as large as possible. In the
embodiment shown here, the spacing of one of the connection
elements 20 from the thermoelectric element is larger than its edge
length.
[0064] Exactly one connection element 20 can generally be provided.
The use of more than one connection element 20 is also conceivable
and covered by the invention.
[0065] In the embodiment, the four connection elements 20 are
located in the corner regions of the solid bodies 10, 12. They are
all exactly at the same distance from the thermoelectric
element.
[0066] The primary heat exchanger comprising the molded bodies 10,
12 provides a very good thermal coupling of the generated cold or
heat of the thermoelectric element. Due to the cross-sectional area
increasing starting from the thermoelectric element, the thermal
flow is brought to a larger surface so that heat loss arises which
is as small as possible on a coupling to a further element such as
to a further thermoconductive element.
[0067] The thermoelectric element is preferably clamped between the
molded bodies 10, 12 without a significant heat bridge arising due
to the connection element or elements.
[0068] The molded bodies 10, 12 are aluminum bodies that are seated
on the thermoelectric element.
[0069] As can be seen from the FIGURE, the molded bodies are
clamped via plastic connections having a small or having a smaller
thermal conductivity.
[0070] It is conceivable to use screws as the connection element or
connection elements.
[0071] It is also possible to use a part such as an injection
molded part as a connection element or as connection elements that
is fastened to one of the molded parts 10, 12 and that latches at
another molded part on assembly.
[0072] Since plastic binders and also other connection elements
represent heat bridges, a cross-selection is used for them that is
as small as possible, whereby the construction support is reduced,
on the other hand. Since the critical loads are deformations at the
total unit that are transmitted to the thermoelectric element via
the rigid primary heat exchanger, i.e. via the molded parts 10, 12,
a stabilization--as can be seen from the FIGURE--is preferred at
all sides and as far away as possible from or outside the
thermoelectric element.
[0073] The described primary heat exchangers can be used sensibly
wherever a temperature difference is to be built up via an
insulation with the aid of a thermoelectric element.
* * * * *