EP1581776A1

EP1581776A1 - Auxiliary cooling device

Info

Publication number: EP1581776A1
Application number: EP03795913A
Authority: EP
Inventors: Klaus Flinner; Georg Hausmann; Stefan Holzer; Jörg STELZER; Fritz Hägele
Original assignee: BSH Bosch und Siemens Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2002-12-30
Filing date: 2003-12-18
Publication date: 2005-10-05
Also published as: DE10261366A1; CN1732363A; AU2003298199A1; WO2004059223A1; US20060053805A1; US7856831B2; US20100018221A1; CN100447503C; US8056347B2

Abstract

The invention relates to an auxiliary cooling device used in a cooling device, comprising a thermoelectric element, especially a Peltier element (2, 3), provided with a heat source (2) and a heat sink (3) which are connected in a circuit. The heat sink (3) is used for directly or indirectly cooling an item which is to be cooled (11). The heat source (2), which is thermally isolated in relation to the heat sink, is in close thermal contact with a heat exchange fluid in a container (1), which is used as a thermal buffer for the waste heat of the cooling process.

Description

Auxiliary cooling device

The present invention relates to an auxiliary cooling device which can be used in a cooling device, in particular a domestic refrigerator without a freezer compartment, in order to temporarily achieve cooling temperatures which are below a normal operating temperature of the cooling device. Conventionally, a user who wants to have storage areas with temperatures above and below 0 ° C. available in a refrigeration device has to buy a combination device or a refrigerator with a so-called 3 or 4 star freezer compartment. The normal cooling compartment and star compartment are cooled by a common refrigerant circuit, although lower evaporator temperatures must be reached in the star compartment than in the normal cooling compartment. Such a refrigerator therefore has a higher specific energy consumption than a comparable device without a star compartment. This is particularly uneconomical if the star compartment is only used occasionally for freezing small quantities.

Many users of a refrigerator also have a freezer that they use for long-term storage of frozen food, so they do not need a star compartment for this purpose. However, many users do not want to do without a star compartment, e.g. Making ice cubes or being able to cool drinks quickly. A freezer is less suitable for both purposes, on the one hand because of the difficulty of safely placing an ice cube maker in it, and on the other because beverages are at risk of freezing at the temperatures reached in the freezer and causing their container to burst. In addition, in contrast to a refrigerator, the freezer is generally not installed in the immediate living area, so that the use of the star compartment is simply and simply more convenient.

The object of the present invention is to provide an auxiliary cooling device for a refrigerator, in particular for a refrigerator without a star compartment, which enables a user to cool or freeze goods such as drinks or water quickly, which takes up little space inside a refrigerator and at Not used does not increase the energy consumption of the refrigerator. 5 The object is achieved by an auxiliary cooling device with the features of claim 1. By placing the container with the heat transfer fluid in a refrigerator, it is cooled to its operating temperature. Starting from this temperature, the Peltier element can be operated in order to quickly cool a good to be cooled, which is brought into thermal contact with the heat sink of the Peltier element

10 time to cool to a temperature that is below the storage temperature of the refrigerator and can be below 0 ° C. The heat released from the heat source during operation of the Peltier element is first released into the first heat transfer fluid, from where it is distributed into the surrounding storage space of the refrigerator. The close thermal contact with the heat transfer fluid

15 allows the heat source of the Peltier element to be kept at a significantly lower temperature during operation than if the heat source were freely located in the storage space of the refrigerator, so that a good efficiency of the Peltier element is achieved.

In order to achieve an effective heat exchange between the heat source and the first heat transfer fluid, the heat source can expediently be attached to a wall of the first container.

The heat sink, in turn, can be in close thermal contact with an ice cube tray 25 if the auxiliary cooling device is to be used for ice cube preparation.

Such an ice cube tray expediently consists of a good heat-conducting material such as aluminum or an aluminum alloy.

30 The heat sink is preferably attached to an underside of the ice cube tray.

A compact design is obtained if the ice cube tray forms an upper end of the first container.

3.5 According to a second embodiment, the thermal contact between the heat sink of the Peltier element and a material to be cooled is produced via a second heat transfer fluid, which is accommodated in a second container. To achieve quick, effective cooling, such a container can be designed of an object to be cooled, in particular in that it has a recess for receiving the object.

The heat sink can be attached directly to a wall of this second container, but it is also conceivable to attach it to a chamber which is connected by lines to the second container, and means for circulating the heat transfer fluid between the chamber and the second container, such as one Pump.

In order to be able to adapt the shape of the recess precisely to changing shapes of objects to be cooled, it is expedient that an inner wall of the second container, which delimits the recess, is flexible. The outer wall of the container, however, can be stiff in order to ensure good handling of the container. Another possibility is that the second container generally has flexible walls and can be shaped into a sleeve, which e.g. can be wrapped around a bottle to be cooled.

If the second container has a rigid outer wall and a flexible inner wall, it is expedient if the chamber in which the heat exchange takes place is lower than the container. If, in addition, a pump is arranged in a supply line for the heat transfer fluid from the chamber into the second container, it generates an overpressure in the second container during operation, which presses its flexible inner wall firmly against an object to be cooled, whereas the heat transfer fluid tends to do so when the pump is switched off to flow into the chamber, thereby releasing the object to be cooled. The same effect can be achieved or enhanced if a bottleneck is formed in a return line of the heat transfer fluid from the second container into the chamber, at which a pressure drop occurs when the pump is running.

Means for reversing the current direction in the circuit of the Peltier element are expedient in order to be able to temporarily interchange the functions of the heat sink and heat source. In the case of an auxiliary cooling device used as an ice cube maker, it is possible in this way to thaw the finished ice cubes superficially and thus to facilitate the release of the ice cubes from their shell. In order to avoid an unnecessary thermal load on a refrigerator in which the auxiliary cooling device is located by its operation, it is expedient to equip the auxiliary cooling device with a temperature sensor in contact with the second heat transfer fluid and with a control circuit which controls the thermoelectric element - and, if available, also the means for circulating the heat transfer fluid - switches off when the temperature detected by the temperature sensor falls below a limit value.

A similar effect can also be achieved with the aid of a time switching device which switches off the thermoelectric element - and, if appropriate, the means for circulating the heat transfer fluid - after a predetermined operating time.

The auxiliary cooling device can be designed as a device which is independent of the refrigerator or, more generally, the refrigerator in which it can be used, and is placed therein only when required. In the case of an auxiliary cooling device permanently installed in a refrigeration device, it may be expedient for reasons of space saving to embed the first container in an insulating wall of the refrigeration device.

Further features and advantages of the auxiliary device according to the invention result from the following description of exemplary embodiments with reference to the attached figures. Show it:

1 shows a schematic section through a first embodiment of an auxiliary cooling device according to the invention, which is specially designed for cooling bottles;

2: a simplified, compact design of the auxiliary cooling device for cooling bottles;

3 shows a schematic section through an auxiliary cooling device for ice cube preparation; 4 shows a perspective view of a second container of an auxiliary cooling device, which is designed as a sleeve:

5 shows a schematic view of a bottle to be cooled, to which the cuff from FIG. 4 is attached;

6: a modification of the auxiliary cooling device from FIG. 1, in which the first container is embedded in the wall of a refrigerator; and

FIG. 7 shows a second modification of the auxiliary cooling device from FIG. 1.

Fig. 1 is a schematic section through an auxiliary cooling device according to the present invention. The auxiliary cooling device comprises a first container 1 which is filled with a heat transfer fluid. A brine or an alcohol-water mixture which has a freezing point below 0 ° C. is generally used as the heat transfer fluid. Since the auxiliary cooling device is intended to be used in the storage compartment of a refrigerator, which generally does not reach temperatures below 0 ° C., the use of pure water as the first heat transfer fluid could also be considered.

A Peltier element is shown schematically here as a heat source 2, which extends over a wall of the first container 1, and a heat sink 3, which forms a wall of a chamber 4. The heat source and the heat sink are shown here as two large-area elements which are connected in series in a DC circuit with supply connections 5. In practice, the Peltier element can comprise a multiplicity of source-sink pairs connected in series, each source or sink being formed by a flat contact between two metals, the current in a sink in each case from a first into the second metal and flows in a heat source from the second metal back to the first.

The chamber 4 is connected to a second container 7 via two pipes 6. An electrically operated pump 8 is arranged in one of the pipelines 6 and can be operated to deliver a second heat transfer fluid between the chamber 4 and to circulate the second container 7. The composition of the second heat transfer fluid can be identical to that of the first.

The second container 7 has the shape of an upwardly open cup with a rigid outer wall 9 and an inner wall 10 formed by a thin, flexible membrane. As a result of its flexibility, the inner wall 10 can fit snugly against a bottle 11 or another object that is used for Cooling is placed in the upwardly open recess 12 of the second container 7.

When the auxiliary cooling device is in operation and the pump 8 and the Peltier element are supplied with current, the second heat transfer fluid cools down at the heat sink 3, is passed by the pump 8 into the second container 7, where it flows around the bottle 11 and cools quickly, and then flows back into chamber 4. The one from the

Heat sink 3 is absorbed heat from the heat source 2 to the

Heat transfer fluid released in the first container 1 and is distributed from there in the storage room of the refrigerator. When the auxiliary cooling device is in operation, the

Power requirement of the refrigerator's refrigerator increases, as this also increases the

Waste heat from the auxiliary cooling device must dissipate. If the auxiliary cooler is not in

Operation, it has no effect on the energy requirements of the refrigerator.

At most, the heat transfer fluids in the containers 1, 7 and the chamber 4 act as a thermal ballast, which extends the on-off cycles of the refrigerator and thus even improves their efficiency.

A control circuit 24 is connected on the one hand to a temperature sensor 25 arranged in contact with the heat transfer fluid in the second container 7 and on the other hand to the pump 8 and a switch 26 in the supply line of the Peltier element 2, 3. The control circuit 24 keeps the pump 8 in operation and maintains the power supply to the Peltier element 2, 3 as long as the temperature detected by the sensor 25 does not fall below a predetermined limit value. If the limit is undershot, it switches off the Peltier element and the pump and does not start them up again until the sensor 25 indicates an increase in temperature. With the help of the sensor 25 and the control circuit 24, undercooling of the bottle 11 can be prevented if it is in the auxiliary cooling device longer than is necessary for cooling. The limit value can be fixed, for example at a temperature of 1 to 2 ° C, around a to prevent accidental freezing of a bottle of water, or it can be adjustable by a user.

In a simpler embodiment, the control circuit 24 and the temperature sensor 25 can also be replaced by a delay circuit, which switches off the pump 8 and the Peltier element 2, 3 again with a fixed delay or a delay that can be set by a user after the auxiliary cooling device has been started up.

2, the Peltier element with heat source 2 and heat sink 3 is attached directly between the first container 1 and the second container 7 mounted thereon. The chamber 4 and the pump 8 are omitted. In this embodiment, despite the absence of forced circulation of the second heat transfer fluid in the container 7, effective cooling of the bottle 11 is possible if the second heat transfer fluid consists essentially of water. Water is known to have its greatest density at approximately 4 ° C., so that when it is cooled below this value at the heat sink 3, it tends to rise in the second container 7 so as to cool the bottle 11.

The auxiliary cooling device shown schematically in FIG. 3 is designed as an ice cube maker. The first container 1 and the Peltier element with heat source 2 and heat sink 3 do not differ from the corresponding parts in FIG. 2. However, the second container 7 from FIG. 2 is replaced by a solid aluminum shell 13, on the top of which a large number of Recesses 14 are formed, which each serve as shapes for ice cubes.

Between the supply connections 5 and the Peltier element, a changeover switch 15 with two switch positions is attached, which allows the direction of current flow through the Peltier element to be reversed. The switching position corresponding to the normal operation of the auxiliary cooling device is the one in which the part of the Peltier element which is in thermal contact with the first container 1 acts as a heat source and the part which is in thermal contact with the aluminum shell 13 acts as a heat sink in order to remove water in the cutouts 14 to freeze. When the water is frozen in the recesses, a user can change switch 15 in his bring another switch position, in which the current direction through the Peltier element is reversed and its part in thermal contact with the aluminum shell 13 acts as a heat source. By briefly heating the shell 13, the ice cubes in the recesses 14 are thawed on the surface, so that they can be easily removed from the recesses.

3, a control circuit 24 and a temperature sensor 25 can also be provided, the temperature sensor 25 being attached here in contact with the aluminum shell 13 and the control circuit 24 the switch 15 when the temperature falls below a limit brings into a third position in which the current flow through the Peltier element 2, 3 is interrupted.

Fig. 4 shows a modified embodiment of the second container. The walls of the second container 17 shown in FIG. 4 are formed by flexible plastic films which are locally welded to one another in order to form a zigzag tubular interior. At one longitudinal end, the foils are welded together flat to form a flat tongue 18. Two pipes 6 for supplying and discharging the second heat transfer fluid, enclosed between the two foils, extend along the tongue 18 and each open onto one longitudinal end of the tubular cavity. A Velcro patch 19 is attached to the side of the tongue 18 facing the viewer in FIG. 4. A Velcro strip 20 complementary to the patch 19, shown in the figure as a dashed outline, is located on the side of the container 17 facing away from the viewer.

FIG. 5 shows the container 17 in use when cooling a bottle 11. The container is wrapped around the belly of the bottle 11 in such a way that the two Velcro fastener parts 19, 20 covered in FIG. 5 come into contact with one another and adhere to one another. Because of its flexibility, the container 17 is able to nestle in a form-fitting manner on bottles with different diameters and thus bring about a very intensive heat exchange between the bottle and the second heat transfer fluid circulating in the second container 17. FIG. 6 shows a modification of the auxiliary cooling device from FIG. 1, in which the first container 1 and the chamber 4 are embedded in a recess 22 in an inner container wall 21 of a refrigerator. With this construction, the space requirement of the auxiliary cooling device inside the refrigerator is considerably reduced. The recess 22 locally reduces the thickness of an insulating foam layer 23 which fills the space between the inner container wall 21 and an outer wall, not shown, of the refrigerator. However, this can be accepted, since the chamber 4, the insulating space between the heat source 2 and the heat sink 3 of the Peltier element and the first container with the heat transfer fluid contained in turn contribute to the thermal insulation of the interior of the refrigerator and thus the effect of the thinner Compensate insulating foam layer 23.

FIG. 7 shows a second modification of the auxiliary cooling device from FIG. 1, in which the second container 7 is placed on a shelf 27 of the refrigerator and the chamber 4 and the first container 1 are arranged directly below the shelf 27. The distance between the chamber 4 and the shelf 27 that appears in the schematic representation of the figure only serves to show the lines 6 for the heat transfer fluid between the chamber 4 and the second container 7 and the pump 8.

The first container 1 and the chamber 4 extend over the entire width of the shelf 27 and therefore have large, mutually facing walls on which the Peltier element 2, 3 can be accommodated. The large wall surfaces also facilitate flexible deformation of the chamber 4 in the event of pressure fluctuations.

A bottleneck 28 is formed in one of the lines 6, in which the heat transfer fluid flows from the second container 7 back into the chamber 4. The heat transfer fluid builds up at this bottleneck 28 when the pump 8 is in operation, so that an overpressure builds up in the container 7, which presses the flexible wall 10 closely against the bottle 11 and thus enables a highly effective heat exchange. The resulting lack of heat transfer fluid in the chamber 4 is compensated for by a deformation of the upper wall of the chamber 4. If the pump 8 is switched off, the tends

Heat transfer fluid to be located in the lower than the second container 7

To collect chamber 4, whereby the upper wall of the chamber bulges and the flexible wall 10 of the second container 7 withdraws from the bottle 11 and releases it.

Claims

claims

1. Auxiliary cooling device for use in a refrigerator, with a thermoelectric element, in particular a Peltier element (2, 3), which comprises a heat source (2) and a heat sink (3), which are connected in a circuit, and with a first container (1) for a first heat transfer fluid, the first heat transfer fluid being in close thermal contact with the heat source (2) and being thermally insulated from the heat sink.

2. auxiliary cooling device according to claim 1, characterized in that the heat source (2) is attached to a wall of the first container (1).

3. Auxiliary cooling device according to claim 1 or 2, characterized in that the heat sink (3) is in close thermal contact with an ice cube tray (13).

4. Auxiliary cooling device according to claim 3, characterized in that the ice cube tray (13) consists of aluminum or an aluminum alloy.

5. Auxiliary cooling device according to claim 3 or 4, characterized in that the heat sink (3) extends over an underside of the ice cube tray (13).

6. Auxiliary cooling device according to one of claims 3 to 5, characterized in that the ice cube tray (13) forms an upper end of the first container (1).

7. Auxiliary cooling device according to claim 1 or 2, characterized in that the heat sink (3) is in close thermal contact with a second heat transfer fluid which is accommodated in a second container (4, 7, 17).

8. Auxiliary cooling device according to claim 7, characterized in that the heat sink (3) is attached to a wall of the second container (7).

9. Auxiliary cooling device according to claim 7, characterized in that the heat sink (3) is attached to a chamber (4) connected to the second container (7, 17) by lines (6) for the heat transfer fluid, and in that it

Has means (8) for circulating the heat transfer fluid between the chamber (4) and the second container (7, 17).

10. Auxiliary cooling device according to one of claims 7 to 9, characterized in that the second container (7) surrounds a recess (12) for receiving an object (11) to be cooled.

11. Auxiliary cooling device according to claim 10, characterized in that an inner wall (10) of the second container delimiting the recess is more flexible than an outer wall (9) of the second container (7).

12. Auxiliary cooling device according to claim 9 and claim 11, characterized in that the chamber (4) is arranged lower than the second container (7).

13. Auxiliary cooling device according to claim 9 and 11 or according to claim 12, characterized in that a bottleneck (28) is formed in a return line (6) of the heat transfer fluid from the second container (7) to the chamber (4).

14. Auxiliary cooling device according to claim 7, 8 or 9, characterized in that the second container (17) has flexible walls and can be shaped into a sleeve.

15. Auxiliary cooling device according to one of claims 7 to 14, characterized in that it has a temperature sensor (25) in thermal contact with the second heat transfer fluid and a control circuit (24) for switching off the thermoelectric element (2, 3) when the by the temperature sensor (25) temperature recorded falls below a limit value.

16. Auxiliary cooling device according to one of claims 7 to 14, characterized in that it comprises a time switching device for automatically switching off the thermoelectric element (2, 3) after a predetermined operating time.

17. Auxiliary cooling device according to one of the preceding claims, characterized in that it has means (15) for reversing the direction of current in the circuit.

18. Refrigerating appliance with an auxiliary cooling device according to one of the preceding claims, characterized in that the first container (1) is embedded in an insulating wall (21, 22, 23) of the refrigerating appliance.