Patent Application
20190049164
The present invention relates to a refrigerator unit and/or a freezer unit having at least one carcass and at least one inner space arranged in the carcass, wherein the unit has at least one refrigerant circuit that serves the cooling of the inner space and wherein the refrigerant circuit has at least one evaporator, at least one compressor, at least one condenser, and at least one restrictor or capillary.
Such refrigerator units and/or freezer units are known in various embodiments from the prior art.
Within the framework of such refrigerator or freezer units, frost occurs at the evaporator that has the result that the efficiency of the evaporator is reduced. There is therefore the need to defrost the evaporator at specific time intervals or at least on the occurrence of a specific quantity of frost at the evaporator.
It is known for this purpose from the prior art to arrange a heating device directly at the evaporator, with this heating device e.g. being able to be an electrical heating.
It is also known from the prior art to carry out a hot gas defrosting by means of which hot refrigerant is conducted into the evaporator. The latter is hereby heated and is defrosted in this manner.
It is the underlying object of the present invention to further develop a refrigerator unit and/or freezer unit of the initially named kind such that it has a particularly simple and efficient defrost heating.
This object is achieved by a refrigerator unit and/or freezer unit having the features of claim 1.
Provision is accordingly made that the refrigerator unit and/or freezer unit has a no frost function that is formed by a bypass that extends as a bypass to the restrictor or to the capillary, with the bypass extending from the condenser directly or indirectly to the evaporator and being configured with at least one valve for shutting off the bypass. This valve is closed when a defrosting is not desired and is open when the evaporator should be defrosted.
In accordance with the invention, the evaporator and the bypass are arranged and configured such that a heat pipe effect is present in the bypass and/or in components of the unit connected upstream and/or downstream thereof.
A heat pipe effect is to be understood such that the refrigerant evaporates at the hot end of the heat pipe and condenses, and in so doing releases heat, at the other end or in another region of the heat pipe.
A heat pipe represents a particularly efficient possibility of heat transfer and in the present case serves to defrost the evaporator as required or at specific points in time. The heat pipe is formed in the present case by at least one bypass line, also simply called a “bypass” within the framework of the invention, and/or by components such as line sections of the refrigerant circuit connected upstream and/or downstream thereof, with the bypass line extending in the bypass to the restrictor or capillary that connects the condenser to the evaporator.
A particularly efficient heat transfer from the condenser to the evaporator is brought about by the heat pipe effect.
The bypass can extend directly from the condenser to the evaporator or also indirectly from the condenser to the evaporator, which is to be understood such that the bypass is not arranged directly at the condenser or at the evaporator, but that rather one or more elements of the refrigerant circuit or of the unit such as a refrigerant collector are interposed.
Provision is made in a conceivable embodiment of the invention that the bypass extends between the condenser and a collector for the refrigerant connected downstream of the evaporator.
In normal operation of the refrigerant circuit, the refrigerant moves from the evaporator into the collector in which liquid, non-evaporated refrigerant is collected before the evaporated refrigerant is conducted into the compressor.
Provision is made in a further embodiment of the invention that the collector is located within the cooled inner space or preferably outside thereof.
It is thus particularly preferred if the collector is attached to the heat side, that is, not in the cooled inner space.
In this case, the bypass extends between the condenser and said collector and the refrigerant moves from there through the suction line into the evaporator. Conversely, the backflow of the condensed refrigerant takes place through the suction line and the collector back to the condenser.
Provision is made in a further embodiment of the invention that the bypass extends between the condenser and the suction pipe that extends between the evaporator and the compressor.
It is conceivable that the bypass extends between the condenser and the suction pipe that extends between the evaporator and the compressor.
In an embodiment of the invention, the collector is located in the cooled inner space.
Provision can furthermore be made that the collector is located outside the cooled inner space.
Provision is made in accordance with a further embodiment of the invention that the condenser is connected to at least one heat accumulator and is preferably arranged in a liquid bath, in particular in a water bath.
It is thus particularly preferred if the condenser is in thermally conductive communication with at least one heat accumulator, for example with a liquid bath and in particular with a water bath.
It is thus conceivable that the condenser is located within a liquid bath. In operation of the refrigerant circuit, the waste condenser heat is thus dissipated to the water bath; the water bath thus serves as a heat buffer and as a heat reserve for the defrosting of the evaporator or of a heat exchanger at the evaporator.
Provision can furthermore be made that the evaporator is configured such that the backflow of the condensed refrigerant into the condenser takes place by gravity.
The refrigerant liquefied as part of the heat pipe effect thus runs back into the condenser solely due to the effect of gravity and evaporates there again.
This process is continued for so long as the condenser or the heat accumulator connected thereto can dissipate sufficient heat or for so long until the valve or another shut-off means of the bypass is opened.
In a further embodiment of the invention, the evaporator is thermally connected to at least one cold accumulator, with the bypass being arranged such that heat can be supplied to the cold accumulator by means of the bypass.
It is also conceivable here that the bypass is directly or indirectly connected to said cold accumulator. This cold accumulator can, for example, be a latent heat accumulator.
Conveying means can furthermore be provided that are arranged such that they convey air to or through the condenser.
It is conceivable here that these conveying means, that can, for example, be configured as one or more fans, are switched off when the defrost operation of the evaporator is running to be able to provide an amount of heat at the condenser that is as large as possible and to keep the heat dissipation due to enforced convection as small as possible.
It is also conceivable to let such a fan run, in particular when the room heat should be used by means of the condenser. In this case, the room heat is ultimately transferred to the condenser and is supplied from the condenser directly or indirectly to the evaporator by means of the heat pipe effect.
Further details and advantages of the invention will be explained in more detail with reference to an embodiment shown in the drawing.
There are shown:
The carcass can be designed with a full vacuum insulation system. It is to be understood by this that a full vacuum insulation 20 is located between the inner side or the inner container and the outer skin or outer jacket of the unit. This full vacuum insulation can comprise a film bag in which a core material such as pearlite is located. This film bag is welded in a vacuum tight manner at its open sides. There is a vacuum in the interior of the film bag so that a thermal resistance that is as large as possible is provided in the carcass. Alternatively or additionally to this, a corresponding full vacuum insulation can be present in the closure element, that is, in the door, flap or drawer of the unit.
A full vacuum insulation is here preferably understood within the framework of the present invention such that the carcass and/or the closure element of the unit comprises a continuous vacuum insulation space over more than 90% of the insulation surface.
No further heat insulation materials are preferably present except for the full vacuum insulation.
The envelope of the film bag is typically a diffusion-tight covering by means of which the gas input in the film bag is reduced so much that the increase in thermal conductivity caused by the gas input of the vacuum insulation body that is produced is sufficiently small 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 flow rate of the cover is preferably <10−6 mbar*l/s*m2 and particularly preferably <10−6 mbar*l/s*m2 (measured according to ASTM D-3985). This gas flow rate applies to nitrogen and to oxygen. There are likewise low gas flow rates for other types of gas (in particular steam), preferably in the range from <10−2 mbar*l/s*m2 and particularly preferably in the range from <10−3 mbar*l/s*m2 (measured according to ASTM F-1249-90). The aforesaid small increases in the thermal conductivity are preferably achieved by these small gas flow rates.
The above-named values are exemplary, preferred indications that do not restrict the invention.
The present invention is not, however, restricted to such full vacuum refrigerator units or full vacuum freezer units, but rather also comprises refrigerator or freezer units having conventional insulation, for example in the form of PU foam.
Reference numeral 30 designates the evaporator of the unit. It is located within the refrigerated inner space and is connected to the collector 40 at the outlet side. The suction line 50 extends from the collector to the compressor 60.
The condenser 70 adjoins the compressor 60 and the refrigerant flows in operation of the refrigerant circuit, that is, of the compressor 60, from said condenser 70 over the capillary 80 back into the evaporator 30. A condensation of the refrigerant takes place in the condenser 70, with heat being dissipated. An evaporation of the refrigerant takes place in the evaporator, whereby heat is withdrawn from the refrigerated inner space.
The collector 40 has the task of collecting non-evaporated refrigerant from the evaporator 30 so that the compressor 60 is only acted on by gaseous refrigerant.
Reference numeral 110 designates a drier around which the capillary 80 is wound that connects the condenser outlet to the evaporator inlet.
A bypass or a bypass line is designated by reference numeral 90 and extends from a region of the condenser 70 at the outlet side to the collector 40. The shut-off valve 100 is located in this line 90.
If the evaporator is to be defrosted, the valve 100 is opened, which has the result that refrigerant flows from the condenser 70 through the line 90 into the collector 40 and from there into the evaporator 30. The evaporator and the bypass 90 and the collector 40 are here configured and arranged such that a heat pipe arises, that is, liquid refrigerant evaporates and condenses in the region of the evaporator. A particularly high amount of heat can thereby be dissipated in the region of the evaporator so that a particularly efficient defrosting of the evaporator takes place. The compressor 60 is preferably switched off during this process.
The heat pipe effect can take place in the bypass 90 and/or in the collector 40 and/or in the evaporator 30 itself.
A particularly high amount of heat is transported due to the heat pipe effect so that a particularly efficient defrosting of the evaporator 30 takes place.
The difference from
It must be named as a further difference from
A heat accumulator that serves as a heat reserve for the defrosting of the heat exchanger at the evaporator can be arranged at the condenser. The heat exchanger at the evaporator can, for example, be designed as a latent heat accumulator.
In addition to the elements shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 003 245.6 | Mar 2016 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/000321 | 3/10/2017 | WO | 00 |
