METHOD FOR OPERATING A DOMESTIC REFRIGERATION APPLIANCE, IN WHICH A MISTING RATE IS ADAPTED, AND DOMESTIC REFRIGERATION APPLIANCE

Abstract

A domestic refrigeration appliance has a separate storage area in an internal space into which foodstuffs, forming storage items, can be introduced. A liquid fluid can be introduced in the storage area independently of the internal space. For keeping the storage items fresh in the storage area a first operating mode and a storage mode, different therefrom, can be carried out. In the storage mode an aerosol mist generated by a misting device of the domestic refrigeration appliance is introduced as a fluid, and a misting rate of the aerosol mist during the storage mode is matched to a setpoint misting rate in dependence on at least one misting device-specific influencing parameter and/or a fluid-specific influencing parameter and/or a storage area-specific influencing parameter. There is also described a domestic refrigeration appliance.

Claims

1-13. (canceled)

14. A method for operating a domestic refrigeration appliance, the refrigeration appliance having an internal space formed with a separate storage area configured to receive foodstuffs to be stored therein as storage items and configured for a liquid fluid to be introduced in the storage area independently of the internal space, the method which comprises: keeping the storage items fresh in the storage area by operating the refrigeration appliance in a first operating mode and in a storage mode different from the first operating mode; in the storage mode, introducing an aerosol mist generated by a misting device of the domestic refrigeration appliance as a fluid and matching a misting rate of the aerosol mist during the storage mode to a setpoint misting rate in dependence on at least one parameter selected from the group consisting of a misting device-specific influencing parameter, a fluid-specific influencing parameter, and a storage area-specific influencing parameter.

15. The method according to claim 14, which comprises predetermining a constant setpoint misting rate over an entire storage time period of the storage items, and adapting a current misting rate such that the entire storage time of the storage items is divided into at least two time intervals and a misting rate in a first time interval of the storage mode is within a tolerance interval of a misting rate in a second time interval of the storage mode and the misting rates of the at least two time intervals lie within a tolerance interval of the setpoint misting rate.

16. The method according to claim 15, wherein the storage time period is at least two days and each of the first and second time intervals is one day.

17. The method according to claim 15, which comprises setting the misting rates in the time intervals with values of between 0.4 g and 0.6 g per 100 cm.sup.2 during the storage mode according to at least one misting device-specific influencing parameter and/or a fluid-specific influencing parameter.

18. The method according to claim 17, which comprises setting the misting rates according to at least one parameter selected from the group consisting of a water hardness and a storage area-specific influencing parameter.

19. The method according to claim 17, which comprises setting a mist quantity to between 0.4 g and 0.6 g per 100 cm.sup.2, in 15 to 20 discharge cycles in the storage area with cycle times of between 55 seconds and 65 seconds, and setting a number of discharge cycles and/or a duration thereof during the storage mode according to at least one parameter selected from the group consisting of a misting device-specific influencing parameter, a fluid-specific influencing parameter, and a storage area-specific influencing parameter.

20. The method according to claim 14, which comprises adapting the misting rate during an implementation of the storage mode to a loading quantity of the storage area with specific storage items and/or a total volume of the storage area as a storage area-specific influencing parameter.

21. The method according to claim 14, which comprises adapting the misting rate during an implementation of the storage mode according to at least one fluid-specific influencing parameter selected from the group consisting of a temperature of the fluid to be misted, a temperature alteration of the fluid to be misted, a temperature in the surroundings of a tank comprising the fluid to be misted and a temperature alteration of a tank comprising the fluid to be misted.

22. The method according to claim 14, which comprises adapting the misting rate during an implementation of the storage mode according to at least one fluid-specific influencing parameter selected from the group consisting of a filling height of the fluid to be misted in a tank of the domestic refrigeration appliance and a water hardness of the fluid.

23. The method according to claim 14, which comprises adapting the misting rate during the implementation of the storage mode according to a total operating time of the misting device as a misting device-specific influencing parameter.

24. The method according to claim 14, which comprises adapting the misting rate during the implementation of the storage mode according to a service life of a component of a refrigerating circuit of the domestic refrigerating appliance.

25. The method according to claim 24, wherein the component is an evaporator of the domestic refrigerating appliance.

26. The method according to claim 14, which comprises introducing the aerosol mist in accordance with a type, a quantity and a position of the storage items in the storage area, which at times are at least locally limited in a storage area zone.

27. The method according to claim 14, which comprises, for keeping the storage items fresh in the storage area, carrying out a refreshing mode as a first operating mode, and thereby introducing the fluid into the storage area for adjusting an application of the fluid onto the storage items in the storage area according to a reduced mass of the storage items in comparison with a fresh mass thereof and, as a result, to thereby increase a mass of the storage items.

28. A domestic refrigeration appliance, comprising: a housing having an internal space with a separate storage area configured therein for foodstuffs as storage items; a misting device for introducing a liquid fluid into said storage area independently of said internal space; and a control unit for controlling said misting device in accordance with the method accordance with claim 14.

Description

[0054] Exemplary embodiments of the invention are described in more detail hereinafter with reference to the schematic drawings. The single figure shows a perspective view of an exemplary embodiment of a domestic refrigeration appliance according to the invention.

[0055] In the figure a domestic refrigeration appliance 1 which, for example, may be a refrigerator is shown in a schematic view. The domestic refrigeration appliance 1 comprises a housing 2 which surrounds an internal container 3. The internal container 3 defines with its walls an internal space 4 in which foodstuffs may be introduced for storage and preservation. Cold air is introduced into the internal space 4, said cold air being provided by a refrigerating circuit 5 provided schematically with the reference numeral. The refrigerating circuit 5 may comprise, for example, a compressor which is arranged in a machine chamber. Moreover, an evaporator which is arranged in the internal space 4 or at least thermodynamically coupled thereto may also be provided. The refrigerating circuit 5 may also have a condenser which is preferably arranged outside the internal container 3, in particular in a rear region of the housing 2.

[0056] In the exemplary embodiment, the domestic refrigeration appliance 1 comprises a storage area 6 which, although it is arranged in the internal space 4, is separated by a partition 7. The partition 7 thus divides the internal space 4 into a partial volume 8 and the storage area 6. The storage area 6 also comprises a drawer 9 into which foodstuffs may also be introduced.

[0057] The domestic refrigeration appliance 1 is designed with its refrigerating circuit 5, so that different levels of ambient humidity may be set in the partial volume 8 and in the storage area 6. The domestic refrigeration appliance 1 may, for example, be a no-frost appliance.

[0058] Preferably, in this connection the storage area 6 may be a compartment in which, in particular, temperatures of between greater than 0° C. and 4° C. are set. In specific embodiments, the temperatures in the remaining partial volume 8 may be slightly higher and may also be set by the user.

[0059] The internal space 4 and thus also the storage area 6 are able to be closed on the front side by a door 10.

[0060] The domestic refrigeration appliance 1 also comprises the humidifying device 11 which is also provided merely symbolically with a reference numeral. The humidifying device 11 is designed to bring sufficient moisture into the storage area 6. To this end, it may comprise a blower and/or fan otherwise present. Moreover, an air duct system is provided. In particular, the humidifying device 11 comprises a container and/or a tank into which water, in particular as fluid, is introduced. The humidifying device 11 also preferably comprises at least one further container into which an additive is introduced. This may then be mixed with the water from the tank for carrying out a hygienization mode and then introduced into the storage area 6 as mist or vapor.

[0061] The humidifying device 11 also comprises a unit, in particular a misting device, by means of which this fluid may be misted or evaporated. In this connection, it may be provided that this unit is an electric heating unit or a low pressure atomizer or a rotating disk and thus a rotary atomizer. Preferably, it is provided that this unit is an ultrasonic nebulizer or membrane nebulizer. The mist produced thereby is conducted by means of a duct into the storage area 6, wherein small inlet openings are arranged to this end at specific positions, the mist being conducted via said openings into the volume of the storage area 6.

[0062] The humidifying device 11 also comprises a control unit, in particular a control and/or evaluation unit, by means of which the control of the ambient humidity in the storage area 6 is regulated. In this connection, a sensor or a plurality of sensors may also be provided, said sensors detecting information about parameters of the storage area 6 and/or the introduced storage items and delivering said information to the control unit, wherein the control is carried out according to this information. In this connection, at least one temperature sensor and/or at least one humidity sensor and/or at least one weight sensor and/or a sensor for detecting the type and/or the freshness state of the introduced storage items may be provided.

[0063] In the exemplary embodiment it is provided that the domestic refrigeration appliance 1 with its humidifying device 11 is configured to implement a storage mode and a refreshing mode and a hygienization mode.

[0064] Foodstuffs in the form of vegetables and fruit after harvest discharge moisture to the surroundings, until a product-specific ambient humidity has been set. As a result, these food products lose fresh mass. The products become limp. If the relative air humidity in the storage area 6 is adjusted according to the equilibrium moisture content of the stored storage items, the loss of humidity may be reduced. Other types of vegetables, such as for example onions, require a relatively low air humidity which, for example, is 65% rH. Other vegetables or fruit require a relatively high air humidity which is greater than or the equal to 90% rH, in particular between 90% rH and 95% rH. For active humidity control the storage compartment and/or the storage area 6 comprises a system in which different operating modes may be set for keeping the storage items fresh. In particular, four different operating modes may be supplied here. It is provided here that the first operating mode is a refreshing mode in which in a relatively short time a very high level of mist is input and thus a very high level of aerosol mist is introduced. A second operating mode is the storage mode in which a quite specific adaptation is carried out relative to the quantity of the aerosol mist and the temperature and the surrounding humidity.

[0065] A third operating mode for keeping the storage items fresh is a drying mode. In this drying mode, no mist is produced. A fan of the misting device, optionally depending on a sensor, for example a humidity sensor, transports air from the internal space 4, which preferably is a refrigerator space, into the storage area. A corresponding air volume escapes via openings in a cover of the storage area 6 or optionally through leaks between the cover and a drawer of the storage area 6. The air transported into the storage compartment and/or the storage area 6, is dependent on the selected cryogenics of the domestic refrigeration appliance and in this connection whether it is a so-called no-frost appliance or a static appliance. Moreover, the relative air humidity of the transported air also depends on the refrigerating cycle of the domestic refrigeration appliance which means that this is dependent on whether the refrigerating circuit is active or inactive and/or how long the refrigerating circuit is active and how long it is inactive. If these states are observed during the operation of the fan, in the storage area 6 the air humidity may be reduced relative to a further third operating mode, namely a neutral mode. In the drying mode, the fan may be operated synchronously with the running time of the refrigeration compartment or even asynchronously. As a result, depending on the refrigerator, air containing different levels of relative humidity may be introduced into the storage area 6. It is also possible that a control is carried out according to the relative air humidity in the storage area 6 or even in the refrigeration compartment.

[0066] In the aforementioned fourth operating mode for keeping the storage items fresh, the neutral mode, the system is in standby mode, and in standby mode the fan does not run. The storage area 6 is subjected to conditions which are predetermined by a superordinate control of the domestic refrigeration appliance in which the storage area 6 is located.

[0067] In the aforementioned storage mode, the misting rate may be set by a user. The misting rate varies for different foodstuffs, such as fruit or vegetables, so that according to the storage items the misting rate which is adapted thereto may be set individually. Thus, for example, herbs or salads require a misting rate of approximately 10 g per day up to 12 g aerosol mist per day for a specific volume of, for example, 23 liters of a storage area 8 and/or a floor surface of the storage area 8 of approximately 0.13 m.sup.2. Fruit or mushrooms require in this case a lower misting rate which, for example, is 2 g per day.

[0068] The quantity of mist discharged into the storage area 6 in the case of a relatively long storage time which is several days, preferably more than ten days, may in particular be introduced uniformly over the stored products and/or the product surface. The quantity of mist introduced into the storage area 6, in particular aerosol mist, is kept as uniform as possible over the storage time.

[0069] The misting rate required for the storage compartment and/or the storage area 6 may preferably be adapted according to the loading quantity and also the volume of the storage area 6. After a relatively short time, for example after one to two minutes, the aerosol mist is deposited on the foodstuffs, amongst other things. Therefore, the dimensioning of the storage area 6 and also the droplet size of the aerosol mist are parameters which preferably have to be taken into account in the control of the misting device and the fan for transporting the generated aerosol mist, with regard to a uniform distribution of the mist which is introduced. It is possible for these influencing parameters to have been previously determined and stored as reference values in a control unit, so that the desired quantity of the mist and the distribution is implemented as required and according to the situation, and a misting rate which is adapted very individually to these influencing parameters is produced. Therefore, the current actual misting rate is compared with a setpoint misting rate and in the case of an undesired deviation, in particular with a deviation outside a tolerance interval which is also in turn predeterminable, a corresponding adaptation takes place immediately. It may also be provided that such an undesired deviation is already prevented in advance, wherein by a corresponding detection of parameter values a possible occurrence of an actual misting rate outside the tolerance interval for a setpoint misting rate is avoided.

[0070] For hygiene reasons, and thus in order to halt bacterial growth on the storage items, the introduction of the aerosol mist is preferably carried out at intervals and thus in corresponding cycles. As a result, sufficient mist is introduced and also sufficient time remains for the aerosol mist to drop down and for the storage items to absorb this moisture.

[0071] When introducing the aerosol mist into the storage area 6 the time of a mist impulse and/or discharge cycle is selected such that this mist fills the storage area 6 as completely as possible without the mist escaping from the vents of the storage area 6.

[0072] The misting rate which is produced by the misting device also depends on storage area-specific influencing factors and/or fluid-specific influencing factors and/or misting device-specific influence factors. In this connection, an ambient temperature and a water temperature of the fluid provided for the misting are taken into account. In a closed storage area 6, the introduction of the aerosol mist is preferably carried out cyclically. In particular, misting rates of 0.5 g per day and per 100 cm.sup.2 are introduced, wherein this is preferably carried out with a number of 15 to 20 discharge cycles having one respective mist impulse duration and/or cycle duration of between 55 seconds and 65 seconds.

[0073] Preferably, these product-specific setpoint misting rates, which are then preferably stored as reference values in the control unit, and the respective actual misting rates, which are storage item-specific, are then compared with corresponding stored reference values.

[0074] Preferably, inlet openings for introducing the aerosol mist into the storage area 6 are located in a front zone of the storage area 6 so that the accessibility and facility for cleaning is also improved thereby. These openings may be preferably positioned in the cover or the drawer of the storage area 6, so that the aerosol mist to be introduced is distributed as uniformly as possible over the bottom surface. Preferably, these ventilation openings are located in a rear zone and are thus at a distance from the mist inlet openings in the front zone.

[0075] In addition to the already-mentioned temperatures as influencing factors, it may also be provided that a misting rate drops according to a filling height of the fluid to be misted in a tank and this is compensated over time by the misting rate being adapted. This may take place via a piezo element, in particular a piezo-ceramic of the mist generator, which represents the misting device. However, in order to be able to introduce a mist quantity into the storage area 6 which is as uniform as possible, via a complete filling of the tank, i.e. up to the maximum filling height, for example, at least the mist impulse duration is shown as a function of the operating time and the filling height and the adaptation of the misting rate carried out as a function thereof. In this connection, correction factors which are stored in a memory of the control unit may be taken into account. By these correction factors, the misting rate is preferably kept in a set range, relative to one day as a time interval unit of an entire storage time, and relative to a surface, and thus a setpoint misting rate is sought. In this connection, the mist quantity discharged in the storage area 6 is produced, preferably between 0.4 g per day and per 100 cm.sup.2 storage surface up to 0.6 g per day per 100 cm.sup.2 storage surface.

[0076] Moreover, for adapting a current misting rate the loading of the storage area 6 and/or the volume of the storage area 6 may be taken into account as further influencing factors. The mass and/or the surface of the storage items may also be considered relative thereto.

[0077] It may also be provided that a mist impulse duration relative to the running time of the misting device is also stored in the memory of the control unit. It is then assumed that the filling state of the fluid in the tank is only altered by the misting device but not by the user as long as the tank has not been removed. If this tank has been removed for filling, then it is assumed in this controller that the user has filled up the tank up to the set level, in particular the maximum level.

[0078] For detecting the filling state of the water tank it is also possible that the filling state is detected via a sensor, for example via a capacitive sensor or via an ultrasonic measurement. Thus the misting rate may be corrected via the controller according to the filling state.

[0079] In order to take into account the influence of the ambient temperature on the temperature of the storage area 6 and thus also of the misting device, corresponding correction values or correction factors may be stored in the memory of the control unit.

[0080] The temperature may also be detected by sensor. As a result, the influence of the surface tension of the fluid on an optionally undesirable deviation of the misting rate may be partially taken into account. This surface tension, however, may also be detected by measurement technology, for example by a force measurement. Moreover, the water hardness of the fluid to be misted may also be detected and considered as influencing parameters, so that this influencing factor is also taken into account here in order to adapt the misting rate such that it is corrected within a tolerance interval around a predetermined setpoint misting rate.

[0081] Due to the water hardness, deposits may be formed on the piezo element of the misting device, which may contribute to the impairment of the mist generating rate. Therefore, it is preferably provided that this piezo element is decalcified, wherein this is indicated to a user preferably acoustically or optically via the control unit.

[0082] It may also be provided that the misting rate is influenced by altering the electrical voltage of this piezo element and in this connection an adaptation has to take place in order to be able to compensate for this alteration.

[0083] It is also possible that the frequency of the electrical operating voltage of this piezo element is altered in order to influence the aerosol droplet size and thus also to influence the misting rate. By means of this embodiment, the dropping time of these aerosol droplets may be varied and thus the distribution of the aerosol mist may be influenced.

[0084] The misting device also reduces its misting rate over its entire operating time. Thus the misting rate may be reduced in otherwise constant conditions. For example, after several 1000 operating hours, for example after 3000 operating hours, the misting rate is reduced by 30 percent. In order to take into account these misting device-specific influencing factors, and then also in order to be able to keep the actually produced misting rate at the desired setpoint misting rate, the running time of the misting device may be detected and correspondingly corrected. Correction factors of the misting rate are assigned to the running time of the misting device, for example by means of a table. Thus the running time may be stored as a number, wherein a counter unit, for example, then matches a time interval thereto of preferably one day. Depending on the status of the counter unit, the factor for the correction of the running time of the mist impulse is used in the control program for the adaptation.

[0085] In order to keep the equilibrium moisture content of the stored storage items as far as possible at the respective individual level, in terms of time the aerosol mist has to be introduced into the storage area 6 so that the moisture losses of the storage items but also the losses due to condensation on the walls, the floor and the cover or caused by opening the storage area 6 for the removal or the storage of storage items, are compensated. To this end, one or more humidity sensors may be present for controlling the mist input and which are preferably connected so that they permit sufficiently accurate information about the relative air humidity in the storage area 6. Preferably, these sensors may be arranged in the region of a door and/or in the region of an evaporator of a refrigerating circuit of the domestic refrigeration appliance and/or at a cool air inlet in the case of a no-frost appliance.

[0086] Alternatively, the mist input may be controlled according to the running time of the refrigeration compartment, for example of an evaporator or a cold air inlet, and thus also device-specific influencing factors for adapting the misting rate may be taken into account. In a so-called standby time of the compressor or a standby time of the cold air inlet, the temperature in the refrigeration compartment and thus also in the storage area rises. As a result, the air in the storage area may absorb more moisture. The relative air humidity drops. In order to counteract the drop in the relative air humidity a short mist impulse, preferably in addition to the already discharged mist impulses, may be discharged into the storage area 6. As a result, it is achieved that the relative air humidity in the storage area 6 is kept as constant as possible for each time interval of a storage time.

[0087] Preferably, it is provided that the humidity applied to the storage items is detected, wherein the mist deposit on the storage items is detected. To this end, in particular, a detection unit which operates with infrared radiation is provided. This detection unit is arranged in the domestic refrigeration appliance. The absorption ranges of water are located in the wavelength range of between 1.920 nm and 1.950 nm and/or between 1.400 nm and 1.450 nm which may then be detected by sensor. The absorption may then be taken into account as a measurement of the film of moisture on the storage items or even for determining the entire water contents of the foodstuffs and thus of the storage items, even without wetting. For establishing this the infrared source of this unit is activated and the storage items illuminated thereby. An infrared receiver of this unit detects the radiation reflected by the storage items. A comparison of this radiation without a film of moisture, which then, for example, may be stored as a reference value in the control unit, then permits information to be provided about the film of water and/or mist deposit present on the storage items.

[0088] A reflection of light in the visible spectral range is also a measurement of the wetting of the storage items by water and/or a mist deposit. In this case, a correspondingly operating light source may illuminate the storage items and a corresponding detector, for example a photodiode, detects the reflected radiation. The voltage discharged by the detector is compared with a comparison value, in particular determined from the detector voltage without the film of water. A measurement of a control variable for scattering the mist input and thus the misting rate in the storage area is also permitted thereby.

[0089] The water content may also be determined by a further alternative measuring method. This may be determined, for example, via an acoustic measuring method, by means of ultrasound signals between 20 kHz to 10 gHz or by a terahertz measuring technology. The terahertz radiation has a penetration depth in the storage items. Therefore, this radiation is better suited to determining the wetting of the storage items. In this connection, in the disclosed alternative methods it may also be provided that the stored product is identified and/or may be input in further detail in terms of its type and design, so that the measurements which are relevant thereto are more accurate and more relevant to the situation. It may also be provided that a camera is provided which permits the recording of an image relating to the contents of the storage area 6.

LIST OF REFERENCE NUMERALS

[0090] 1 Domestic refrigeration appliance

[0091] 2 Housing

[0092] 3 Internal container

[0093] 4 Internal space

[0094] 5 Refrigerating circuit

[0095] 6 Storage area

[0096] 7 Partition

[0097] 8 Partial volume

[0098] 9 Drawer

[0099] 10 Door

[0100] 11 Humidifying device