Patent Application
20160123650
This application claims the priority, under 35 U.S.C. ยง119, of German application DE 10 2014 222 113.7, filed Oct. 29, 2014; the prior application is herewith incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a refrigeration device with a heat circulation system.
During operation of a refrigeration device the air in the interior of the refrigeration device generally has a lower temperature than the air in the external area of the refrigeration device. Since cold air can take up a smaller volume of moisture than warm air, with a high air humidity water can condense on a surface of the interior of the refrigeration device. The result of a condensation of water can be an undesired wetting or formation of condensation on the goods stored in the refrigeration device.
To prevent a condensation of water in the interior of the refrigeration device, refrigeration devices can have electrical frame heating available to them, which heats up the frame of the refrigeration device.
The object of the present invention is to specify a refrigeration device in which the condensation of water on the frame of the refrigeration device is reduced.
In accordance with one aspect, the inventive object is achieved by a refrigeration device having a heat source and a heat circulation system for heating an opening area of a frame of the refrigeration device. The heat circulation system contains a heat transport substance, and the heat circulation system has a heat take-up area and frame heating. The heat source is embodied to emit a quantity of heat through the heat take-up area to the heat transport substance in the heat circulation system, in order to obtain a heated-up heat transport substance. The heat circulation system is embodied to convey the heated-up heat transport substance from the heat take-up area to the frame heating, and the frame heating is embodied to emit the quantity of heat taken up by the heat transport substance to the opening area of the frame of the refrigeration device.
The technical benefit achieved by this for example is that a condensation of water on the opening area of the frame of the refrigeration device is prevented. In order to avoid a condensation of water on the opening area refrigeration devices often need a separate heating of the frame of the refrigeration device. The frame heating can conventionally be provided by a lengthening of the condenser in a refrigerant system of the refrigeration device, which is placed in the form of a pipe around the opening. The lengthening of the condenser requires an increased quantity of refrigerant in the refrigerant system of the refrigeration device however, which leads to a greater use of resources of the refrigeration device.
The opening area of the frame of the refrigeration device is the area of the surface of the frame on the front side of the refrigeration device which, with a closed refrigeration device, is in contact with the refrigeration device door of the refrigeration device and which is revealed when the refrigeration device door is opened and is thereby in contact with the exterior of the refrigeration device.
Since only a slight heating is required for reducing the condensation of water at the opening area of the frame of the refrigeration device, the use of a heat circulation system, such as e.g. a thermosiphon or a heat pipe, is sufficient in order to achieve a sufficient heating of the opening area of the frame of the refrigeration device.
There is recourse here to a component of the refrigerant circulation of the refrigeration device, which, because mechanical energy is expended during the cooling process, generates heat and therefore serves as the heat source for the heat circulation system of the present invention. The heat generated by the heat source is transferred by the heat take-up element to the heat transport substance of the heat circulation. The heat transport substance emits the heat taken up through the frame heating to the opening area of the frame of the refrigeration device.
The frame heating is the area of the heat circulation system, i.e. for the example the area of a pipe of the thermosiphon or of the heat pipe, which is in thermal contact with the opening area of the frame of the refrigeration device. The frame heating is the area of the heat circulation system which is disposed below the surface of the opening area of the frame of the refrigeration device in the frame of the refrigeration device.
The heat transmission process of the heat circulation system runs exclusively on the basis of a temperature difference in the refrigeration device and therefore does not need any additional energy. This enables energy-saving heating of the opening area of the frame to be insured by the heat circulation system, and the size of the refrigerant circuit of the refrigeration device can be reduced, through which the quantity of refrigerant in the refrigeration device can be reduced.
Thus, by using a heat circulation system, an effective and energy-saving heating of the opening area of the frame of the refrigeration device can be achieved, by which the quantity of condensed water at the opening area of the frame of the refrigeration device can be effectively reduced.
A refrigeration device is especially understood as a household refrigeration device, i.e. a refrigeration device which is used for housekeeping in households or in the field of gastronomy and especially serves to store foodstuffs and/or drinks at specific temperatures, such as a refrigerator, a freezer, a fridge/freezer combination, a chest freezer or a wine cooling cabinet.
In an advantageous form of embodiment of the refrigeration device the heat circulation system contains a thermosiphon or a heat pipe.
The technical benefit achieved by this is that an effective and energy-saving heat transmission from the heat source to the opening area of the frame of the refrigeration device is made possible by the thermosiphon or heat pipe.
A thermosiphon is a passive heat circulation system which makes possible an exchange of heat by using the natural convection in a vertical, closed fluid circuit. The thermosiphon contains a heat transport substance which is heated in the lower area of the thermosiphon by a heat source, which results in an evaporation of the heat transport substance, which causes the substance to rise in the vertical fluid circuit. In the upper area of the thermosiphon this results in a condensation of the heat transport substance and an emission of heat, through which the heat transport substance falls in the vertical fluid circuit as a result of the force of gravity. Thus a thermosiphon contains a two-phase gas mixture with a constant pressure and a constant temperature and is operated by a temperature difference in different external areas of the thermosiphon. Thus an effective and energy-saving conveyance of heat from the heat source to the opening area of the frame of the refrigeration device can be made possible by a thermosiphon.
A heat pipe is likewise a passive heat circulation system, which makes possible an exchange of heat through a heat transport substance in a closed pipe. The method of operation of the heat pipe is similar to the method of operation of the thermosiphon, only that the ends of the heat pipe are not connected to one another and therefore no pipe circuit is present. Instead the inner walls of the heat pipe are equipped with a coating that has a high capillary effect. When the heat transport substance, because of a temperature difference of areas outside the heat pipe, flows into a core area of the pipe, then the heat transport substance, because of the capillary effect, can flow back again on the outer side of the inner area of the pipe. Through this an effective heat transmission from the heat source to the opening area of the frame of the refrigeration device can likewise be made possible.
In a further advantageous form of embodiment of the refrigeration device the heat source includes a compressor or a condenser.
The technical benefit achieved by this is that the compressor or the condenser, as a component of the refrigerant circuit of the refrigeration device already present, can be used as a heat source and through this the waste heat necessarily arising through the operation of refrigeration device can be used for heating the opening area.
The compressor is a mechanically-operated component which sucks up the refrigerant vapor from the evaporator of the refrigerant circuit and discharges it at a higher pressure to the condenser. The condenser is a heat exchanger, in which, after the compression, the evaporated refrigerant of the refrigerant circulation is condensed by emission of heat to an external cooling medium, e.g. the surrounding air. Thus, by the use of the compressor or the condenser as heat source in combination with a heat circulation system, an effective heating of the opening area of the frame of the refrigeration device can be insured.
In a further advantageous form of embodiment of the refrigeration device the heat source contains a condenser made from multi-port extruded pipe.
The technical benefit achieved by this is that the use of a condenser made of multi-port extruded pipe (MPE condenser) as a heat source makes possible an especially effective transmission of heat to the heat circulation system.
An MPE condenser has a large internal surface, which makes possible an effective transmission of heat from the refrigerant to the external area of the MPE condenser. When there is a thermally-conductive contact between the MPE condenser and the heat circulation system, an effective heat transmission from the MPE condenser to the heat transport substance in the heat circulation system can take place.
In a further advantageous form of embodiment of the refrigeration device the condenser made of multi-port extruded pipe contains a plurality of channels which are each separated by webs.
The technical benefit achieved by this is that the use of channels which are separated by webs enables a large volume of refrigerant in the refrigerant circulation to flow through the MPE condenser. If the webs consist of a thermally-conductive material a large inner surface is available to take up a quantity of heat from the refrigerant and emit it to the heat circulation system.
In a further advantageous form of embodiment of the refrigeration device the heat transport substance contains an alkane or a fluorinated hydrocarbon, preferably tetrafluorethane or isobutane, and especially preferably water.
The technical benefit achieved by this is that the heat transport substances have advantageous heat-transporting properties. For this reason alkanes, fluorinated hydrocarbons and water are suitable especially for the use of a two-phase gas mixture in a heat circulation system of a refrigeration device. Tetraflourethane and isobutane have proved to be especially advantageous heat transport substances, which are suitable for use in refrigeration devices. Isobutane and water is especially preferred here because of its very low harmfulness. In a further preferred form of embodiment the quantity of isobutane in the heat circulation system amounts to between 25 g and 57 g.
In a further advantageous form of embodiment of the refrigeration device the heat transport substance has a fluid aggregate state in the heat take-up area before taking up the quantity of heat, wherein the heat transport substance in the frame heating has a gaseous aggregate state before emitting the quantity of heat.
The technical benefit achieved by this is that an especially effective heat transmission from the heat source to the opening area of the frame of the refrigeration device is made possible by the use of a two-phase mixture in the heat circulation system.
In a further advantageous form of embodiment of the refrigeration device the heat take-up area and the frame heating of the heat circulation system are separated by an area of insulation.
The technical benefit achieved by this is that thermal insulation between the heat take-up area and the frame heating is insured by the area of insulation. Through this a temperature gradient between the external area of the heat take-up area and the external area of the frame heating is guaranteed, which is necessary to guarantee a transmission of heat from the heat take-up area to the frame heating through the heat transport substance, through which an effective heating of the opening area of the frame of the refrigeration device is insured.
In a further advantageous form of embodiment of the refrigeration device the area of insulation contains an area with an insulation material, which is selected from the group consisting of styrofoam, mineral wool and plastic foam.
The technical benefit achieved by this is that an especially effective heat insulation is achieved by the insulation materials.
In a further advantageous form of embodiment of the refrigeration device the frame heating is in thermally-conductive contact with the opening area of the frame in order to guarantee an effective emission of the quantity of heat to the opening area of the frame.
The technical benefit achieved by this is that, through the thermally-conductive contact between the frame heating and the opening area of the frame, an effective heating of the opening area of the frame is insured. In particular what is achieved by the thermally-conductive contact is that the majority of the heat emitted by the frame heating is not emitted at random to the refrigeration device, but the opening area of the frame is heated explicitly. The thermally-conductive contact can contain a direct contact between the frame heating and the opening area of the frame. The thermally-conductive contact can contain an indirect contact, which can be realized by a thermally-conductive element, such as a thermally-conductive metal for example, through which heat is conducted from the frame heating to the opening area of the frame.
In a further advantageous form of embodiment of the refrigeration device the surface of the frame heating makes up more than 60% of the surface of the opening area of the frame, preferably more than 80%.
The technical benefit achieved by this is that the large proportion of the surface of the frame heating, which is in thermal contact with the surface of the opening area of the frame, makes effective heating of the opening area of the frame possible. In particular the large proportion of the surface of the frame heating insures an even heating of a large part of the opening area of the frame. What is achieved by this is that almost all areas of the opening area of the frame which are in thermal contact with the frame heating are sufficiently heated and this enables condensation of water on the opening area of the frame to be prevented.
In a further advantageous form of embodiment of the refrigeration device the heat source contains a heat source surface, wherein the heat take-up area includes a heat receiving surface which is disposed in parallel to the heat source surface in order to guarantee an effective take-up of the quantity of heat by the heat take-up area.
The technical benefit achieved by this is that by the parallel arrangement of heat source surface and heat take-up surface, a large quantity of heat can be transmitted from the heat source to the heat take-up area of the heat circulation system. The heat source surface can contain an external surface of the heat source, such as the external surface of an MPE condenser for example. The heat take-up surface can contain a surface of the heat take-up area of the heat circulation system. The heat take-up surface of the heat take-up area can transmit a large quantity of heat to the heat circulation system, since the heat transport substance flows past the heat take-up surface and thus emits a large quantity of heat in a specific time interval. The parallel arrangement of the heat source surface and the heat take-up surface prevents heat emitted by the heat source escaping into the refrigeration device, but enables it to be taken up by the heat take-up surface.
In a further advantageous form of embodiment of the refrigeration device the heat source is connected to the heat take-up area by a thermally-conductive element in order to guarantee an effective take-up of heat by the heat take-up area.
The technical benefit achieved by this is that an effective transmission of heat from the heat source to the heat take-up area of the heat circulation system is insured by the thermally-conductive element. In particular what is achieved by the thermally-conductive element is that a majority of the heat emitted by the heat source is not emitted at random to the refrigeration device but explicitly reaches the heat take-up area.
In a further advantageous form of embodiment of the refrigeration device the thermally-conductive element contains a thermally-conductive material which is selected from the group consisting of silver, copper, iron and glass.
The technical benefit achieved by this is that an especially effective conduction of heat is achieved by the thermally-conductive materials.
In a further advantageous form of embodiment of the refrigeration device the heat circulation system has a filler nozzle for filling it with the heat transport substance.
The technical benefit achieved by this is that the system can be filled with the heat transport substance through the nozzle. The filler nozzle can subsequently be closed in order to prevent a subsequent escape of the heat transport substance from the heat circulation system.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a refrigeration device with a heat circulation system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
Referring now to the figures of the drawings in detail and first, particularly to
The refrigeration device 100 has a refrigerant circuit with an evaporator, a compressor, a condenser and a throttle valve. The evaporator is a heat exchanger, in which the liquid refrigerant is evaporated after expansion by taking up heat from the cooling medium, e.g. the air in the interior of the refrigerator. The compressor is a mechanically-operated component which sucks refrigerant vapor from the evaporator and emits it at a higher pressure to the condenser. The condenser is a heat exchanger, in which after the compression the vaporized refrigerant is condensed by emitting heat to an external cooling medium, e.g. the surrounding air. The throttle valve is an apparatus for constantly reducing the pressure by narrowing the cross-section.
The refrigerant is a fluid which is used for the transmission of heat into the refrigerating system which, at lower temperatures and lower pressure of the fluid, takes up heat and at higher temperature and higher pressure of the fluid emits heat, wherein this usually encompasses changes of state of the fluid.
If the refrigerator door 101 of the refrigeration device 100 is opened and the external air has a high humidity, then moist external air flows into the interior of the refrigeration device 100 and, in doing so, introduces moisture into the interior of the refrigeration device 100. This increases the humidity of the air in the interior of the of the refrigeration device 100. Since the cool air in the interior of the refrigeration device 100 can take up a lower quantity of moisture than the warmer external air, the result is a condensation of water in the opening area 105 of the frame 103 of the refrigeration device 100 located in the vicinity of the opening of the refrigeration device 100, if the area has a lower surface temperature.
Between the heat take-up area 109 and the frame heating 111 the heat circulation system 107 includes an area of insulation 117, which is embodied to prevent an external flow of heat outside the heat circulation system 107 between the heat take-up area 109 and the frame heating 111. The heat circulation system 107 includes a substance line 119, which is embodied to transport the heat transport substance in the flow direction 121 from the heat take-up area 109 to the frame heating 111 and from the frame heating 111 to the heat take-up area 109.
During the refrigeration process in a refrigeration device 100 the interior of the refrigeration device 100 is cooled. However the refrigeration in the cooling circuit of the refrigeration device 100 only succeeds through the expenditure of mechanical energy by various components of the cooling circuit, such as compressor, evaporator or condenser for example. The components of the cooling circuit themselves create heat when expending mechanical energy, through which the components of the cooling circuit function as heat sources 123. The heat created by the heat source 123 during the operation of the cooling circuit in the refrigeration device 100 is emitted to the heat take-up area 109 of the heat circulation system 107 in order to heat the heat transport substance. A thermally-conductive element 125 can be fitted between the heat source 123 and the heat take-up area 109, in order to make possible an effective transmission of heat.
The heat transport substance heated in the heat take-up area 109 is transported to the frame heating 111 of the heat circulation system 107 in the flow direction 121 through the substance line 119. Through the frame heating 111 the heated heat transport substance emits the heat taken up to the environment of the heat circulation system 107 and is cooled thereby. The frame heating 111 is embodied such that it is in thermally-conductive contact with the opening area 105 of the frame 103 of the refrigeration device 100. This enables an effective transmission of heat to the opening area 105 of the frame 103 to take place, through which a condensation of moisture at the opening area 105 is prevented. The cooled heat transport substance is conveyed again through the substance line 119 into the heat take-up area 109, in which a renewed heating of the heat transport substance takes place.
The inventive frame heating 111 in a refrigeration device 100 as a closed-circuit heat system 107 enables the refrigeration circuit of the refrigeration device 100 to be designed smaller. The quantity of heat transport substance which is needed for the frame heating 111 is used in a heat circulation system 107 separate from the refrigerant circuit of the refrigeration device 100. This enables the quantity of refrigerant in the refrigeration device 100 to be reduced and efficient and cost-effective operation of the refrigeration device 100 is insured.
All features explained and shown in connection with individual forms of embodiment of the invention can be provided in different combination with the inventive subject matter in order to simultaneously realize its advantageous effects.
The area of protection of the present invention is given by the claims and is not restricted by the features explained in the description or shown in the figures.
The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:
| Number | Date | Country | Kind |
|---|---|---|---|
| 102014222113.7 | Oct 2014 | DE | national |
