EP3051231B1 - Refrigerating and/or freezing apparatus - Google Patents

Description

The present invention relates to a refrigerator and / or freezer that cools an interior of the refrigerator and / or freezer with the aid of several thermoelectric elements.

In the prior art, the production of refrigerators and / or freezers based on thermoelectric elements is considered to be of little promise because such a device has poor efficiency and high demands on the external heat exchanger for removal of those produced by the thermoelectric element or elements Waste heat calls.

So-called multi-stage Peltier elements are known from Peltier technology, which treats thermoelectric elements, with which it is possible to achieve larger temperature differences than with single-stage Peltier elements.

The outer Peltier element is dimensioned so that it can pump off the waste heat from the next inner Peltier element. Due to the low efficiency of Peltier elements, a significantly higher cooling capacity of the outer Peltier element is required.

With regard to the cooling capacities required in a refrigeration device, the heat exchanger for the removal of the waste heat is the critical variable. A locally installed two-stage Peltier element would generate too much waste heat, which would create a large temperature gradient when it was removed. This large temperature gradient would conflict with the effect of the Peltier element.

However, these considerations are by no means limited to refrigerators and / or freezers, but apply in general to heat-insulated containers.

The heat-insulated container has at least one temperature-controlled interior, which can be cooled or heated, so that a temperature below or above the ambient temperature of e.g. 21 ° C results.

DE 11 34 395 B relates to a refrigerator which is equipped with two cooling devices which are assigned to two refrigerated goods compartments of different temperature, of which one compartment is designed as a freezer compartment and which is separated from the normal refrigerating compartment by a flap and by an intermediate wall accommodating an electrothermal cooling device such that the heat-emitting side of the electrothermal cooling device built into the partition protrudes into the normal cooling compartment.

The object of the invention is to provide a refrigerator and / or freezer which is cooled with the aid of thermoelectric elements without attaching too much importance to the prejudices prevailing in the prior art.

This object is achieved by the thermally insulated container with the features of claim 1.

This arrangement of the thermoelectric element makes it possible to dissipate the heat of the thermoelectric element particularly advantageously with the aid of the temperature level prevailing in the first cooling space. This makes it possible to control the critical size of the waste heat generated by the thermoelectric element.

A vacuum element can preferably be used as the insulation element, the outer boundaries of which consist of a high barrier film which closes the inner region defined by the high barrier film in a diffusion-tight manner. Such a vacuum element is typically called a vacuum insulation body.

A particularly preferred embodiment is one in which thermal insulation, which consists of a full vacuum system, is arranged between the inner wall of the container delimiting the interior and the outer skin of the container. This means thermal insulation that consists exclusively or predominantly of an evacuated area that is filled with a core material. The boundary of this area can be formed, for example, by a vacuum-tight film and preferably by a high barrier film. Thus, between the inner wall of the container, preferably a device, and the outer skin of the container, preferably a device, only such a film body can be present as thermal insulation, which has a region surrounded by a vacuum-tight film, in which vacuum prevails and in which a core material is arranged. Foaming and / or vacuum insulation panels as thermal insulation or other thermal insulation apart from the full vacuum system between the inside and the outside of the container or device are preferably not provided.

This preferred type of thermal insulation in the form of a full vacuum system can be between the wall delimiting the interior and the outer skin of the body and / or between the inside and the outside of the closure element, e.g. a door, flap, cover or the like.

The full vacuum system can be obtained in such a way that an envelope made of a gas-tight film is filled with a core material and then vacuum-tight is sealed. In one embodiment, both the filling and the vacuum-tight sealing of the casing are carried out at normal or ambient pressure. The evacuation is then carried out by connecting a suitable interface, for example an evacuation socket, which may have a valve, incorporated into the casing to a vacuum pump. Normally, ambient or ambient pressure prevails outside the casing during the evacuation. In this embodiment, it is preferably not necessary at any time during manufacture to introduce the casing into a vacuum chamber. In this respect, in one embodiment, a vacuum chamber can be dispensed with during the production of the vacuum insulation.

A vacuum-tight or diffusion-tight sheathing or a vacuum-tight or diffusion-tight connection or the term high-barrier film is preferably understood to mean a sheathing or a connection or a film by means of which the gas entry into the vacuum insulation body is reduced to such an extent that that caused by gas entry conditional increase in the thermal conductivity of the vacuum insulation body over its service life is sufficiently small. A period of 15 years, preferably 20 years and particularly preferably 30 years, is to be assumed as the life span, for example. The increase in the thermal conductivity of the vacuum insulation body over its service life caused by the introduction of gas is preferably <100% and particularly preferably <50%.

The area-specific gas passage rate of the casing or of the connection or of the high barrier film is preferably <10-5 mbar * l / s * m ² and particularly preferably <10-6 mbar * l / s * m ² (measured in accordance with ASTM D-3985) . This gas passage rate applies to nitrogen and oxygen. For other types of gas (in particular water vapor) there are also low gas passage rates, preferably in the range of <10-2 mbar * l / s * m ² and particularly preferably in Range of <10-3 mbar * l / s * m ² (measured according to ASTM F-1249-90). These low gas passage rates preferably achieve the aforementioned slight increases in thermal conductivity.

A wrapping system known from the field of vacuum panels are so-called high barrier films. In the context of the present invention, this is preferably understood to mean single-layer or multilayer films (which are preferably sealable) with one or more barrier layers (typically metallic layers or oxide layers, aluminum or an aluminum oxide preferably being used as the metal or oxide), which above requirements (increase in thermal conductivity and / or area-specific gas passage rate) are sufficient as a barrier against the gas entry.

The above-mentioned values or the structure of the high barrier film are exemplary, preferred statements which do not limit the invention.

In the invention, the thermoelectric element is preferably embodied by a Peltier element, which can form a temperature difference between two surfaces by the supply of current. The two surfaces typically run parallel to one another and are spaced apart from one another.

The second cooling space can preferably be used as a freezer compartment.

According to the invention, the thermoelectric element for cooling the second cooling space is in contact with a heat exchanger which is also in contact with a thermoelectric element for cooling the first cooling space.

The waste heat from the thermoelectric element for cooling the second cooling space is released to the heat exchanger in regular operation of the refrigerator and / or freezer. The heat exchanger is also in a thermal connection with the cooling side or heat side of the other thermoelectric element for cooling the first cooling space.

According to the invention, there is more than one thermoelectric element for cooling the first cooling space. The thermoelectric element for cooling the first cooling space is preferably also arranged in an insulating element which surrounds the first cooling space. The thermoelectric element for cooling the first cooling space is not arranged in an area that is arranged between the first cooling space and the second cooling space, but in a region between the first cooling space and an outer wall of the cooling device.

The thermoelectric element for cooling the first cooling space is in a thermal or physical connection with the outer wall of the refrigerator and / or freezer. Here, the outer wall is used to dissipate any waste heat generated at the thermoelectric element and to dissipate it to the surroundings or to conduct heat required by the thermoelectric element and to draw it from the surroundings. If the thermoelectric element is arranged in a vacuum body, there is a high barrier film between the outer wall of the device and the waste heat surface or heat absorption surface of the thermoelectric element, but this does not prevent effective heat conduction.

The heat exchanger, which is connected to both the thermoelectric element for cooling the first and the second cooling space, is the inner container itself or part of the inner container of the first cooling space. For example, a metal, in particular an aluminum, is suitable as the material for this heat exchanger. The use of a metal makes it possible to distribute or absorb the waste heat to be dissipated or heat to be absorbed particularly quickly and to cool or heat it with the aid of the temperature prevailing in the first compartment, preferably the first cooling space, or the other thermoelectric elements.

According to a further feature of the present invention, the thermoelectric element for cooling the second cooling space is arranged within the insulating element, which separates the first cooling space and the second cooling space. According to the invention, the second temperature level is lower than the first temperature level.

The refrigerator and / or freezer preferably comprises a heat exchanger which is arranged in the second cooling space and which represents a thermally delimited surface which has a colder or warmer temperature than the air present in the second cooling space. Typically, the heat exchanger is arranged in the second cooling space near the thermoelectric element for cooling the second cooling space and is at a lower or higher temperature level than the air present in the second cooling space.

In one embodiment, the thermoelectric element for cooling the second cooling space can be operated in reverse in order to heat the heat exchanger in the second cooling space and to defrost an ice layer that forms on this heat exchanger.

Moisture present in the second cooling room will condense and possibly freeze due to the low temperature at the heat exchanger of the second cooling room. The cooling of the second cooling space by means of the thermoelectric element offers a simple and efficient possibility to design the second cooling space as a so-called "no-frost" cooling space. This is achieved by exchanging the polarity on the thermoelectric element so that the heat exchanger heats the second cooling room. As a result, the ice that may have formed on the heat exchanger melts and can be guided out of the second cooling space using suitable means. In this case, it is particularly advantageous to integrate a line for draining condensation and / or condensation water into the heat exchanger into the insulation, in order to discharge the condensation and / or condensation water through the insulation.

Since the thermoelectric element can be operated as a heat pump with a very high degree of efficiency, the "no-frost" cycle in this structure is associated with very low energy losses.

Accordingly, the thermoelectric element for cooling the second cooling space can preferably be operated in reverse in order to heat the heat exchanger in the second cooling space and to defrost an ice layer that forms on this heat exchanger.

It can be advantageous to provide a line for conveying condensation and / or condensation water from the heat exchanger in the second cooling space, which conducts the water in the direction of an outer skin of the refrigerator and / or freezer in order to evaporate the condensation water and / or condensation water enable. It is preferably possible to transport the condensed water and / or the condensed water to a specific location on the outside of the refrigerator by capillary forces.

In addition, it can be advantageous for the refrigerator and / or freezer if it comprises a fan in the second cooling space in order to support natural convection in the second cooling space.

For "no-frost" operation in a refrigerator and / or freezer, it can be useful to install a fan in the second cooling room if the natural convection that is set is not strong enough to reliably bring the moisture to the coldest point in the room to transport the second cooling room (heat exchanger). It is then advantageous to use a fan with very low power that drives the convection and guarantees that the moisture is transported to the heat exchanger. This prevents ice formation at points other than the heat exchanger and supports successful "no-frost" operation. However, it is advisable to use a fan with very low power, since the electrical power of the fan in the second cooling room is generated as heat and must also be removed.

In one embodiment it is provided that the refrigerator and / or freezer according to the invention is a household appliance or a commercial refrigerator. For example, devices are included that are designed for a stationary arrangement in the household, in a hotel room, in a commercial kitchen or in a bar. For example, it can also be a wine refrigerator. The invention also includes freezers and / or freezers. The devices according to the invention can have an interface for connection to a power supply, in particular to a household power network (for example a plug) and / or a standing or installation aid such as adjustable feet or an interface for fixing within a Have furniture niches. For example, the device can be a built-in device or a free-standing device.

In one embodiment, the device is designed in such a way that it is supplied with an AC voltage, such as, for example, with a domestic network voltage of e.g. 120 V and 60 Hz or 230 V and 50 Hz can be operated. In an alternative embodiment, the device is designed such that it can be operated with direct current of a voltage of, for example, 5 V, 12 V or 24 V. In this embodiment it can be provided that a plug-in power supply is provided inside or outside the device, via which the device is operated. An advantage of using thermoelectric heat pumps in this embodiment is that the complete EMC problem only occurs on the power supply.

In particular, it can be provided that the refrigerator and / or freezer has a cabinet-like shape and has a usable space which is accessible to a user on its front side (in the case of a chest on the top). The usable space can be divided into several compartments, all of which are operated at the same or at different temperatures. Alternatively, only one compartment can be provided. Storage aids such as storage compartments, drawers or bottle holders (in the case of a chest also room dividers) can also be provided within the usable space or a compartment to ensure optimal storage of refrigerated or frozen goods and optimal use of space.

The usable space can be closed by at least one door pivotable about a vertical axis. In the case of a chest, a flap that can be pivoted about a horizontal axis or a sliding lid is conceivable as a closing element. The door or another locking element can be closed are essentially airtight in connection with the body by means of a circumferential magnetic seal. The door or another closure element is preferably also thermally insulated, the heat insulation being able to be achieved by means of a foaming process and, if appropriate, using vacuum insulation panels, or preferably using a vacuum system and particularly preferably using a full vacuum system. If necessary, door racks can be provided on the inside of the door in order to also be able to store refrigerated goods there.

In one embodiment, it can be a small device. In such devices, the usable space defined by the inner wall of the container has, for example, a volume of less than 0.5 m ³ , less than 0.4 m ³ or less than 0.3 m ³ .

The outer dimensions of the container or device are preferably in the range up to 1 m in terms of height, width and depth.

Fig. 1:

eine Ausführungsform des erfindungsgemäßen Kühl und/oder Gefriergeräts in einer Querschnittsansicht.

Further advantages and features of the invention are described in detail below using an exemplary embodiment which is illustrated in the figure. It shows:

Fig. 1:

an embodiment of the refrigerator and / or freezer according to the invention in a cross-sectional view.

Fig. 1 shows a refrigerator and / or freezer, with a first refrigerator 1, which is arranged above a second refrigerator 2. The two are limited Cold rooms through respective insulation elements 3, which define the dimensions of the cold room. Of course, each of the two cold rooms is accessible from the outside via a separate or a common access door (not shown).

One recognizes the thermoelectric element 4 for cooling the second cooling space, which is arranged between the first cooling space 1 and the second cooling space 2. With its surfaces, between which a temperature gradient can be created, it is oriented towards the cold rooms. In normal operation, the second cooling space 2 is cooled by the colder surface of the thermoelectric element 4 to a second temperature level, which is lower than the temperature level of the first cooling space 1. The surface of the thermoelectric element 4 that emits waste heat is in contact with a heat exchanger, which at the same time defines the inner container of the first cold room.

In addition, one can see further thermoelectric elements 7 (in Fig. 1 a total of 3 pieces) which are arranged between the first cooling space 1 and the outside 5 of the refrigerator and / or freezer. Here too, in normal operation, the cold side of the thermoelectric elements 7 is oriented toward the first cooling space and is in thermal connection with the heat exchanger, at which the thermoelectric element 4 emits its waste heat for cooling the second cooling space. The warm side of the thermoelectric elements 7 is in (thermal) contact with the outer surface 5 of the refrigerator and / or freezer and releases the waste heat produced to the environment.

The reference numeral 8 denotes the heat exchanger in the second cooling space, which has a colder temperature than air in the second cooling space 2. Thus, a heat exchanger 8 is first formed Ice layer, provided there is sufficient convection in the second cooling space 2.

The Peltier elements (thermoelectric elements) 7 for cooling the first cooling space 1 serve to maintain the temperature level in the first cooling space 1. They give off their cooling capacity to a heat exchanger 6, which is located in the Fig. 1 corresponds to the inner container of the first cold room 1. The Peltier element 4, which is arranged between the first cooling space 1 and the second cooling space 2, also gives off its waste heat to the heat exchanger 6. Here, the size and insulation of the first cooling space 1 and the second cooling space 2 are dimensioned such that the heat exchanger 6 does not generate any waste heat from the Peltier element 4, which is arranged between the first cooling space 1 and the second cooling space 2, without a large temperature difference from the Peltier elements 7 can transport and can be released into the air via the outer skin 5 of the refrigerator and / or freezer. The outer skin 5 of the refrigerator and / or freezer also acts like a heat exchanger, since heat can be given off to the environment. Reference number 9 denotes an evaporation tray for condensed and / or condensed water.

Claims (7)

1. Refrigeration and/or freezer device, including a first cooled space (1) for cooling to a first temperature level, and a second cooled space (2) for cooling to a second temperature level, wherein the second temperature level is smaller than the first temperature level, wherein the second cooled space (2) is separated from the first cooled space (1) by a thermally-insulating insulating element (3), wherein first thermoelectric elements (7) are provided for cooling the first cooled space (1), which are arranged in a region between the first cooled space and an outer wall (5) of the device, and wherein a second thermoelectric element (4) for cooling the second cooled space (2) is arranged inside the insulating element (3) that separates the first cooled space (1) and the second cooled space (2) from one another and that emits its dissipation heat into the first cooled space (1) in a cooling operation of the second cooled space (2), wherein the first thermoelectric elements (7) for cooling the first cooled space (1) emit their cooling capacity to a heat exchanger (6) that corresponds to an inner container of the first cooled space (1), and the second thermoelectric element (4) for cooling the second cooled space (2) emits its dissipation heat to this heat exchanger (6).
2. Refrigeration and/or freezer device according to any one of the preceding claims, wherein the first cooled space and the second cooled space are arranged in one common housing of the device.
3. Refrigeration and/or freezer device according to any one of the preceding claims, wherein the inner container is made of a metal, preferably aluminum.
4. Refrigeration and/or freezer device according to any one of the preceding claims, further comprising a heat exchanger in the second cooled space, which represents a thermally limited area that has a colder temperature than the second cooled space.
5. Refrigeration and/or freezer device according to claim 4, wherein the second thermoelectric element for cooling the second cooled space can be operated in a reverse manner in order to heat the heat exchanger in the second cooled space and to defrost a layer of ice forming at this heat exchanger.
6. Refrigeration and/or freezer device according to claim 5, further with a line for supplying thaw water and/or condensation water of the heat exchanger in the second cooled space towards an outer skin of the refrigeration and/or freezer device, in order to make an evaporation of the thaw water and/or condensation water possible, wherein preferably the thaw water and/or condensation water is transported to a certain location of a fridge outer side by means of capillary forces.
7. Refrigeration and/or freezer device according to any one of the preceding claims, further comprising a ventilator in the second cooled space in order to support convection in the second cooled space.

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