Temperature-Controlled Container

Abstract

The invention relates to a temperature-controlled container (10) comprising a cooled or heated inner chamber (100) and a thermoelectric element (20), particularly a Peltier element (20), arranged such that said inner chamber (100) is cooled or heated by means of the thermoelectric element (20). In order to control the temperature of the inner chamber (100), a plurality of thermoelectric elements (20) are provided which are arranged to be spaced apart from one another.

Description

The present invention relates to a temperature-controlled container having at least one cooled or heated inner space and having a thermoelectric element, in particular having a Peltier element, that generates cold or heat in the inner space of the container in operation.

Different concepts are known from the prior art for cold production in refrigerator units and freezer units. In all cases, an effective heat exchanger is required both on the refrigerating space side and on the waste heat side for an efficiency which is as high as possible, and thus for good energy efficiency, to keep the temperature difference to be overcome as small as possible. In this connection, the coupling to the region of the cold production and to the refrigerating space as well as to the outside air to which the discharged air is output is of importance.

A major parameter in the required refrigeration capacity of a refrigerator unit or freezer unit is the thermal insulation which surrounds the cooled inner space. If the thermal insulation is improved, the requirement for refrigeration capacity is reduced. With a small refrigeration capacity, the provision can take place by simpler means than by compression refrigeration machines, namely in particular by a thermoelectric element. The use of a Peltier element is known, for example. A small refrigerator insulated by vacuum insulation thus, for example, only requires a refrigeration capacity of 3-4 W which can e.g. be produced by a thermoelectric element.

There is a special feature in the use of Peltier elements in that the refrigeration capacity produced and the waste heat occur in direct spatial proximity—a refrigerant as a heat carrier is not present. In this case, the heat transfer to the cooled inner space as well as to the outside air to which the heat is output is of special importance: It is known from the prior art to improve this heat transfer in Peltier refrigerator units such as portable coolers by ribbed recuperators and by an air flow produced by fans. Their power requirement is at a similar order of magnitude to that of the Peltier element.

These considerations are, however, by no means restricted to refrigerator units and/or freezer units, but rather apply to thermally insulating containers in general, with thermally insulated containers covered by these considerations having at least one temperature-controlled inner space which can be cooled or heated so that a temperature is produced in the inner space below or above the ambient temperature of e.g. 21° C.

It is the underlying object of the present invention to further develop a temperature-controlled container of the initially named kind such that a leading off of the produced heat into the temperature controlled inner space for the purpose of its heating or heat maintenance or to the outside for the purpose of cooling the inner space is achieved in the best possible manner.

This object is achieved by a temperature-controlled container having the features of claim 1.

Provision is accordingly made that a plurality of thermoelectric elements which are arranged at a spatial distance from one another are present for the temperature control of the inner space of the container.

It is thus the underlying idea of the present invention not only to use a single thermoelectric element for the temperature control of the cooled inner space, but rather to use at least two thermoelectric elements. An improved temperature control (heating or cooling) of the inner space can thereby be carried out since the waste heat can be easily distributed over the outer skin of the unit in the case of cooling and can be easily distributed over the wall bounding the inner space in the case of heating.

In addition, the use of a plurality of thermoelectric elements, which are arranged spatially distributed, provides the opportunity of a specific temperature control of the inner space so that different refrigeration/heating capacities can be provided at different points there.

Provision is preferably made that the container has main surfaces and that at least two of the thermoelectric elements are arranged at different main surfaces. “Main surfaces” are understood in the case of a cabinet-shaped container as the two side walls, the top wall, the bottom and the rear wall, and in the case of a chest-shaped container as the two side walls, the front wall, the rear wall and the bottom.

It is conceivable that at least one respective thermoelectric element is arranged in each of the main surfaces or in some of the main surfaces. It is, for example, conceivable in the case of a cabinet-shaped container that at least one respective thermoelectric element is arranged in the side walls, in the bottom and in the top wall.

Provision can be made alternatively or additionally thereto that one or more thermoelectric elements are arranged in the closing element (door, lid, flap, front of a drawer, etc.) by means of which the temperature-controlled inner space can be closed.

Provision is made in a further embodiment of the invention that the thermoelectric element or elements is/are thermoconductively connected to a preferably passively operating primary heat exchanger. A passively operating heat exchanger is to be understood as an element that conducts heat from or to the thermoelectric element or transfers it otherwise, without an energy supply being required for this purpose.

The primary heat exchanger can be arranged at the cold side and/or at the hot side of the thermoelectric element.

It is conceivable that the primary heat exchanger consists of a metallic body, preferably of aluminum, or comprises a metal, in particular aluminum. The metal body or bodies is/are thus connected to the cold side and/or to the hot side of the thermoelectric element and conducts/conduct heat toward the thermoelectric element or conducts/conduct heat away from the thermoelectric element.

It is advantageous for a coupling of the waste heat, i.e. for a transfer of the heat without a large temperature gradient, if the primary heat exchanger or heat exchangers has/have a cross-sectional surface which increases as the distance from the thermoelectric element increases so that the heat or waste heat is distributed over a larger surface.

It is particularly advantageous if the thermoelectric element or elements are arranged such that they are connected in a thermoconductive manner or in another heat-transferring manner to the outer skin and/or to the inner wall of the container bounding the inner space such that the outer skin and/or the inner wall serve(s) as a secondary heat exchanger.

The outer skin of the container and/or the inner wall of the container bounding the inner space can consist of metal in part or in total or can comprise metal, with the metal preferably being aluminum.

If at least one primary heat exchanger and at least one secondary heat exchanger are provided, they are connected to one another directly or indirectly in a heat-transferring manner, in particular an a thermoconductive manner.

Provision is preferably made that the outer skin and/or the inner wall of the container bounding the inner space consists partly or completely of sheet metal.

Provision is preferably made in this respect that the sheet metal has a thickness of <3 mm, preferably a thickness of 1 to 2 mm.

If the temperature-controlled container is a refrigerator unit and/or a freezer unit, it is sufficient for the distribution of the waste heat over the complete outer skin of the unit if it is made up of an aluminum metal sheet having a thickness of 1 to 2 mm. This outer skin can be located on each side of the carcass or only on some parts of the carcass sides.

Since the cooling energy which is generated is smaller than the waste heat, the demands on the heat exchanger are not so high in the unit interior, i.e. in the inner space. It is nevertheless sensible likewise to produce the inner container, i.e. the wall bounding the inner space, from a sheet metal and preferably from an aluminum metal sheet, with a smaller sheet metal thickness being able to be used for this purpose than for the outer skin.

The container can be designed in the manner of a cabinet and can have a rear wall, two side walls a top and a bottom or, in the case of a chest, can have two side walls, a rear wall, a bottom and a front wall. At least one thermoelectric element can be arranged in each or in at least two of the named walls.

As stated above, the container can have a closing element such as a door, a lid or the like and the at least one thermoelectric element can be arranged in the closing element.

Provision is made in a further embodiment of the invention that different temperature zones exist in the inner space. Cooling zones of different temperatures can thus be provided, for example, with the customary temperature of a conventional refrigerating compartment being able to be present in one zone and with the customary temperature of a cold storage compartment being able to present in another zone.

This can e.g. be achieved by a separate control of the individual thermoelectric elements.

This separate control cannot only be used to provide regions of different temperature within the cooled or heated inner space, but rather also to generate a particularly large refrigeration capacity in the case of a particularly large heat input in a region of the inner space, e.g. by the placing in of refrigerated goods or frozen goods. The same applies accordingly to the reverse case of a heated container.

At least one control or regulation unit can thus be provided which controls all the plurality of thermoelectric elements the same or differently so that they produce a capacities which are identical or which differ from one another.

An embodiment is particularly preferred in which a thermal insulation is arranged between the inner wall bounding the inner space and the outer wall 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 core 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 unit and the outer wall of 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 core material is arranged. A foaming and/or vacuum insulation panels 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.

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.

The full vacuum system can be obtained such that an envelope of a gas-tight film is filled with a core material and is subsequently sealed in a gas-tight manner. In an embodiment, both the filling and the vacuum-tight sealing of the envelope take place at normal or environmental 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.

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.

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*m² and particularly preferably <10-6 mbar*I/s*m² (measured according to ASTM D-3985). This gas flow permeation 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*m² and particularly preferably in the range from <10-3 mbar*I/s* m² (measured according to ASTM F-1249-90). The aforesaid small increases in the thermal conductivity are preferably achieved by these small gas permeation rates.

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.

The above-named values or the make-up of the high barrier film are exemplary, preferred values which do not restrict the invention.

The container in accordance with the invention is preferably a refrigerator unit and/or freezer unit whose inner space is cooled by the thermoelectric elements. The case is also covered by the invention that it is a container whose inner space is heated by the thermoelectric elements.

The temperature-controlled inner space is either cooled or heated depending on the type of the unit (cooling appliance, heating cabinet, etc.).

The refrigerator unit and/or freezer unit can, for example, be a domestic appliance or a commercial cooling device. 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.

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.

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.

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.

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 m³, less than 0.4 m³ or less than 0.3 m³.

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.

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.

Further details and advantages of the invention will be explained in more detail with reference to an embodiment shown in the drawing. The only FIGURE shows a longitudinal sectional view through a refrigerator unit and/or freezer unit in accordance with the invention.

In the FIGURE, the carcass of a cabinet-like refrigerator unit and/or freezer unit is marked by the reference numeral 10.

The carcass 10 has two side walls 12, a top 14 and a bottom 16. They bound the cooled inner space 100 together with the rear wall and a door.

As can be seen from the FIGURE, a respective thermoelectric element 20 is provided in the two side walls 12, in the top wall 14, and in the bottom 16.

Exactly one such thermoelectric element can generally be provided per wall. However, the case is also covered by the invention that two or more than two thermoelectric elements are present in one or more walls.

The arrangement of one or more thermoelectric elements at the rear side of the unit is also conceivable and covered by the invention.

Each of the thermoelectric elements 20 is connected in a heat-transferring manner, in particular in a thermoconductive manner, to a respective one heat exchanger 30, 40 both on the cold side facing the inner space 100 and on the outwardly directed hot side. These primary heat exchangers 30, 40 are metal bodies, e.g. composed of aluminum.

In the operation of the thermoelectric elements 20, heat is extracted from the cooled inner space over their cold sides and by means of the heat exchanger 30 and of the inner wall I. This heat is discharged to the environment via the hot side of the thermoelectric element 20, via the heat exchanger 40 and via the outer wall A.

As can further be seen from the FIGURE, the cross-section of the primary heat exchangers 30, 40 increases, starting from the thermoelectric element 20 toward the outer wall A and also toward the inner wall I which bounds the cooled inner space 100 together with the inside of the door. In this manner, the waste heat which is extracted from the inner space 100 by means of the thermoelectric elements 20 can be distributed over a larger surface without a larger temperature gradient.

The outer unit side is formed by the outer wall A which comprises in total or regionally a metal sheet, preferably an aluminum metal sheet.

In the embodiment shown here, this metal sheet forms the outer side A of the side walls 12, of the top 14 and also of the bottom 16. The rear side and/or the door can also be correspondingly formed on the outer side.

The metal sheet forming the outer wall A forms the secondary heat exchanger which is connected in a heat-transferring manner, in particular in a thermoconductive manner, to the primary heat exchangers 40.

The inner wall I is likewise formed by a metal sheet, in particular by an aluminum metal sheet. The inner wall I is connected in a heat-transferring manner, in particular in a thermoconductive manner, to the primary heat exchangers 30.

The term “heat exchanger” in accordance with the present invention includes any desired element that is suitable for transferring heat. In the preferred embodiment, the heat exchangers are formed by metallic bodies.

Reference numeral 50 denotes the thermal insulation which extends between the inner wall I and the outer wall A of the carcass. This thermal insulation comprises a volume which is bounded by one or more vacuum-tight films and in which a core material, in particular pearlite, is located. Further insulating materials such as foaming and/or vacuum insulation panels are preferably provided between the inner wall I and the outer wall A.

A corresponding full vacuum thermal insulation can also be provided for the door or for another closing element.

The Peltier elements 20 or the other thermoelectric elements are distributed over the unit geometry such that their waste heat is distributed as much as possible over the outer skin A of the unit. The outer skin A can be made up of an aluminum metal sheet having a thickness of 1 to 2 mm for the distribution of the waste heat over the complete outer skin.

Since the cooling energy which is generated is smaller than the waste heat, the demands on the heat exchanger are not so high in the unit interior 100. A metal sheet (e.g. an aluminum metal sheet) is preferably equally used for the inner wall of the unit and can have a smaller thickness than the metal sheet forming the outer skin A or can have an identical configuration.

As stated above, a refrigerator unit and/or a freezer unit or a heated container, in which different temperature zones are present, can be implemented by a separate control of the thermoelectric elements 20. However, the case is generally also covered by the invention that exactly one temperature is present in the cooled or heated inner space 100.

Depending on the interconnection of the thermoelectric elements, they can heat or cool the inner space such that the container in accordance with the invention can be used for both purposes. The container can thus exert a heat-maintaining function. The embodiment thus also applies with conversely controlled thermoelectric elements 20, in which the hot side is at the inside and the cold side is at the outside, to a heated container.

If the container is not required for heating, the same container can be used for cooling by a corresponding control of the thermoelectric elements.

The present invention thus relates to a temperature-controlled container having a thermoelectric heat pump, with more than one thermoelectric element being used at a spatial distance to achieve the desired inner space temperature.

Only thermoelectric elements are preferably used for the temperature control of the cooled inner space.

Claims

1. A temperature-controlled container having a cooled or heated inner space; and having a thermoelectric element, in particular having a Peltier element, that is arranged such that the inner space is cooled or heated by means of the thermoelectric element, characterized in that a plurality of thermoelectric elements that are arranged at a spatial distance from one another are present for the temperature control of the inner space.

2. A container in accordance with claim 1, characterized in that the container has main surfaces; and in that at least two of the thermoelectric elements are arranged at different main surfaces.

3. A container in accordance with claim 1, characterized in that the thermoelectric elements are connected in a thermoconductive manner to a primary heat exchanger which preferably operates passively, with the primary heat exchanger being arranged on the cold side and/or on the hot side of the thermoelectric element.

4. A container in accordance with claim 3, characterized in that the primary heat exchanger consist of a metal body or comprises it, with the metal preferably being aluminum.

5. A container in accordance with claim 3, characterized in that the primary heat exchanger has a cross-sectional area which increases as the spacing from the thermoelectric element increases.

6. A container in accordance with claim 1, characterized in that the thermoelectric element or elements is/are arranged such that it/they are connected in a heat-transferring manner, in particular in a thermoconductive manner, to an outer skin and/or to an inner wall of the container bounding the inner space such that the outer skin and/or the inner wall serve/serves as a secondary heat exchanger.

7. A container in accordance with claim 6, characterized in that the outer skin and/or the inner wall of the unit bounding the inner space consists of metal or comprises metal, with the metal preferably being aluminum.

8. A container in accordance with claim 1, characterized in that the outer skin and/or the inner wall of the container bounding the inner space consist/consists partly or completely of a metal sheet, with provision preferably being made that the metal sheet has a thickness of <3 mm, preferably a thickness of 1 to 2 mm.

9. A container in accordance with claim 1, characterized in that the inner wall bounding the inner space has a smaller thickness than the outer skin of the container.

10. A container in accordance with claim 1, characterized in that the container is designed in cabinet form and has a rear wall, two side walls, a top and a bottom or, in the case of a chest, two side walls, a rear wall, a bottom and a front wall; and in that at least one thermoelectric element is arranged in each or in at least two of the named walls.

11. A container in accordance with claim 1, characterized in that the container has a closing element such as a door, a lid or the like; and in that the at least one thermoelectric element is arranged in the closing element.

12. A container in accordance with claim 1, characterized in that different temperature zones exist in the inner space.

13. A container in accordance with claim 1, characterized in that a control or regulation unit is provided which controls all the plurality of thermoelectric elements the same or differently.

14. A container in accordance with claim 1, characterized in that a thermal insulation is arranged between the inner wall bounding the inner space and the outer wall and comprises a full vacuum system in full or regionally.

15. A container in accordance with claim 1, characterized in that the container is a refrigerator unit and/or a freezer unit.