WO2013000773A2

WO2013000773A2 - Refrigeration device with evaporation pan and auxiliary device for promoting evaporation

Info

Publication number: WO2013000773A2
Application number: PCT/EP2012/061758
Authority: WO
Inventors: Adolf Feinauer; Hans Ihle
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2011-06-29
Filing date: 2012-06-20
Publication date: 2013-01-03
Also published as: DE102011078321A1; WO2013000773A3

Abstract

A refrigeration device, especially a household refrigeration device, comprises at least one storage chamber (3) that can be closed by a door (2), an evaporation pan (9) for evaporating condensed water that is drained off from the storage chamber (3) and an auxiliary device (10, 12) which can be switched on additionally by a control unit (13) to increase the evaporation rate in the evaporation pan (9). The control unit (13) is designed to detect when the door (2) is opened and to control the operation of the auxiliary device (10, 12) based on how many times and/or for how long the door has been opened and/or depending on the ambient temperature (T_ext) and/or to take the change of the temperature (Tv) of an evaporator (4) over time into consideration for controlling the operation of the auxiliary device (10, 12).

Description

Refrigerating appliance with evaporation tray and auxiliary device for

evaporation promotion

The present invention relates to a refrigeration appliance, in particular a household refrigeration appliance such as a refrigerator or freezer, with an evaporation tray for the evaporation of condensate discharged from a storage chamber of the device, and a

Auxiliary device, which is switchable to promote the evaporation of the dew water in the evaporation tray, if necessary.

Each time you open a door of the refrigerator with the ambient air also

Moisture in the storage chamber of a refrigerator and is reflected there over time at the coldest point down, that is, depending on the design of the refrigerator, for example, directly to an evaporator or cooled by the evaporator wall of the storage chamber. From there, the moisture must be removed so that it does not affect the heat exchange between the storage chamber and the evaporator and thus the efficiency of the refrigerator and / or so that drained from this coldest point water does not wet the refrigerated goods. It is therefore usually below this coldest point a gutter or shell provided in which the condensation can collect and from where it through a passage in the

heat-insulating wall of the refrigerator is passed to an evaporation tray. The evaporation tray is located beyond the heat-insulating wall to release moisture evaporating from it freely to the environment. To the

To promote evaporation in the shell, it is traditionally in one

Engine room of the refrigerator mounted on a compressor to pass through

Waste heat to be heated.

Improvements in insulation and cooling in modern refrigeration appliances mean that the ratio of accumulating condensate to the waste heat available at the compressor is becoming increasingly unfavorable. However, if the condensation is faster than it can evaporate in the evaporation tray, it overflows, and the leaking water can damage the unit and its surroundings. One way to replace the lack of waste heat from the compressor is to attach an electrical heater to the evaporation tray. However, it is obvious that the operation of such a heater, especially if he does not

controlled in a demand-oriented manner, which impairs the overall energy efficiency of the refrigeration device and improves efficiency through improved insulation or improved

Largely destroys refrigeration. Although it would be conceivable to attach a level sensor to the evaporation tray and to operate the heater only if it indicates the exceeding of a critical water level. However, such a level sensor must have a high degree of reliability, because if a fault of the level sensor is that an exceeding of the critical water level is not detected, overflowing the evaporation tray threatens with the resulting consequential damage. If, on the other hand, a malfunction of the level sensor leads to the fact that an exceeding of the critical water level is constantly detected, then the heating device runs non-stop, and energy is wasted uselessly. Since such a disturbance does not immediately manifest itself externally, it may be overlooked for a long time and cause considerable costs for the user. However, a level sensor with the reliability required for practice leads to not negligible and often dissuasive for the user costs in the device manufacturing. Object of the present invention is therefore to provide an inexpensive and reliable solution with which sufficient evaporation of condensation can be ensured and at the same time a good energy efficiency of the refrigerator is maintained.

Under a refrigeration device is in particular a household refrigeration appliance understood, ie a refrigeration appliance for household management in households or possibly in the

Catering area is used, and in particular serves to store food and / or drinks in household quantities at certain temperatures, such as a refrigerator, a freezer, a fridge-freezer, a freezer or a wine storage cabinet.

The problem is solved by a refrigeration device, in particular a

Domestic refrigerating appliance, with at least one lockable by a door storage chamber, an evaporation tray for the evaporation of derived from the storage chamber Condensation water and an auxiliary device, which can be switched by a control unit to increase the evaporation rate in the evaporation tray, the control unit is set up to detect an opening of the door and to control the operation of the auxiliary device based on the number and / or duration of detected door openings. The effectiveness of this solution is based on the fact that the air exchange between the storage chamber and the environment with each opening of the door is an essential source of condensate precipitating in the storage chamber and that therefore also the amount of condensation to be evaporated closely related to the number and duration of the door openings ,

To the accuracy with which the operation of the auxiliary device to the accruing

Further, the control unit may be configured to further control the operation of the auxiliary device depending on the

Ambient temperature to control because the amount of moisture that enters the storage chamber together with a given volume of air from the environment, generally increases sharply with the temperature of the air.

To detect the ambient temperature, the control unit may be connected to a suitable temperature sensor.

With comparable reliability cheaper techniques are feasible

Estimation of the ambient temperature on the basis of related variables. Thus, for example, if the refrigeration device comprises a compressor which is operated intermittently in a manner known per se, the control unit can be set up to estimate the ambient temperature on the basis of the duration of an operating phase of the compressor. The duration of an operating phase depends not only on the difference between the switch-on and switch-off temperature of the compressor, but also on the rate at which ambient heat penetrates into the storage chamber and delays its cooling during operation of the compressor. The higher the ambient temperature, the higher the rate, and accordingly, each operating phase lasts longer.

Refrigeration appliances are also known, in which the capacity of the compressor is variable and regulated to a value at which the compressor is continuous or near Run continuously while keeping the temperature of the storage chamber constant. The capacity of the compressor to equalize the flow of heat from the storage compartment environment depends on the ambient temperature, specifically the difference between the ambient temperature and the temperature of the storage chamber, so that the performance to which the compressor is subjected at one such refrigeration device is regulated, also allows a conclusion on the ambient temperature.

Also known are refrigerators in which a storage chamber with a

Humidity sensor is equipped to detect the humidity in the storage chamber and to allow a controlled dehumidification of the air to a tuned to the refrigerated goods contained therein target value. The amount of condensate arising in such a controlled dehumidification can be accurately estimated on the basis of the measured humidity values and can be used to control the auxiliary device.

An indirect estimate of the humidity is also without a special

Humidity sensor possible. Thus, for example, a temperature sensor for detecting the temperature of the evaporator may be arranged on an evaporator cooling the storage chamber in order to detect the change in the evaporator temperature during startup. Moisture condensing on the evaporator delays its cooling, so that by comparing the time course of cooling with a normal course without condensation, the amount of condensation can be estimated, which is reflected in this in an operating phase of the evaporator on this.

If the average operating temperature of the evaporator is so low that

Humidity precipitated as frost, which does not defrost between two phases of operation of the evaporator, then defrosting can be provided for defrosting the evaporator. Liquid condensate essentially only occurs when the

Defrost heater is in operation. Therefore, the control unit is in such a case

Preferably arranged to operate this device together with the defrost heater to quickly eliminate this condensation.

Appropriately, the consideration of the various above-mentioned, the amount of accumulating condensation water influencing variables can be done by the

Control unit is set, with each door open a count size by one increment based on at least one of door opening duration, ambient temperature, compressor run time, compressor capacity, humidity in the storage chamber and

Rate of change of the evaporator temperature selected size, and to operate the auxiliary device when the count size reaches a limit. As an auxiliary device, in particular a heater and / or a fan come into consideration.

Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. From this description and the figures are also features of the

Embodiments, which are not mentioned in the claims. Such features may also occur in combinations other than those specifically disclosed herein. Therefore, the fact that several such features are mentioned in the same sentence or in a different type of textual context does not justify the conclusion that they can occur only in the specific combination disclosed;

instead, it must be assumed that, of several such characteristics, it is also possible to omit or modify individual ones, provided that this is the case

Functionality of the invention is not in question. 1 is a schematic section in the width direction through a household refrigerator according to the present invention;

2 shows a section in the depth direction through the refrigeration device. Fig. 3 is a flowchart of a method for controlling the evaporation

supporting auxiliary device;

4 is a flow chart of one within the scope of the control method of FIG. 3

applicable method for estimating the ambient temperature;

5 is a flowchart of a method for estimating the

Ambient temperature applicable in a refrigeration unit with variable capacity compressor; FIG. 6 shows exemplary temperature profiles on the evaporator of the refrigerator of FIGS. 1 and 2; FIG. and

FIG. 7 is a flowchart of a method of controlling the auxiliary device based on the temperature characteristics shown in FIG. 6; FIG. and

8 is a flowchart of a second method based on the temperature curves of FIG. 6. Figs. 1 and 2 show schematic sections through a household refrigerator, to which the present invention is applicable. The sectional planes of the two figures are shown in the other Fig. As dash-dotted lines l-l and II-II.

The household refrigerator, here a refrigerator, has in the usual way

heat-insulating housing having a body 1 and a door 2 defining a storage chamber 3. The storage chamber 3 is here cooled by a coldwall evaporator 4 arranged on its rear wall between an inner container of the body 1 and an insulating foam layer surrounding it, but it should be immediately obvious to the person skilled in the art that the features of the invention explained below also apply in connection with FIG any other types of evaporator are applicable.

The evaporator 4 is part of a refrigerator which further comprises a compressor 6 housed in a machine room 5 recessed from the cabinet 1 and a condenser not shown in the figures, which may for example be accommodated on the outside of the rear wall of the cabinet 1 or in the machine room 5 ,

At the foot of the cooled by the evaporator 4 rear wall of the storage chamber 3, a collecting channel 7 extends for condensed water, which is reflected at the area cooled by the evaporator 4 of the inner container and flows down there. A pipeline 8 leads from the lowest point of the gutter 7 through the insulating

Foam layer through to an evaporation tray 9, which is mounted on a housing of the compressor 6, to be heated by waste heat of the compressor 6. An electric heater 10 is here in the form of a inside of the Evaporation tray 9 extending heating loop shown; she could too

for example in the form of a film heater on an outer wall 1 1 of

Evaporation tray 9 may be mounted, in which case outside the film heater around still an insulating layer may be provided to ensure that the heater emits its heat substantially in the evaporation tray 9 inside.

In order to promote the evaporation of condensate in the evaporation tray 9, instead of the heater 10 or in addition to this still a fan 12 may be arranged in the engine room 5 so that it drives an air flow over the water level of the evaporation tray 9. Since the on and off times of the

Heater 10 and the fan 12 are linked and preferably the same, the description may be limited to the case that both are present.

Heating device 10 and fan 12 are controlled by an electronic

Control unit 13, which is shown here for simplicity in the engine room 5, but in practice largely arbitrarily on the refrigerator and in particular adjacent to a - not shown - control panel can be arranged. The control unit 13 also controls the operation of the compressor 6 on the basis of a temperature sensor 14 arranged on the bearing chamber 3. As will be explained in more detail below, a simple on-off control of the compressor 6 can be provided within the scope of the invention, in which the control unit 13 turns on the compressor 6, when the temperature of the storage chamber, a switch-on threshold T _a exceeds 3, and it turns off again as soon as the temperature of the storage chamber 3 is below a switch-off threshold T _off. However, it is also a continuous control of the power, in particular the speed of the compressor 6 or switching between numerous discrete non-vanishing power levels of the compressor 6 in dependence on the measured temperature into consideration.

On a side wall of the body 1 an operable by the door 2 switch 15 is mounted, which can serve in a conventional manner for switching on and off a lamp 16 of the storage chamber 3 when opening or closing the door 2. The switch 15 is connected to the control unit 13 to allow detection of the opening and closing of the door 2 by the control unit 13. For some of the control methods described below, a second temperature sensor 17 may be arranged directly on the evaporator 4 in order to control its temperature

To detect temperature and report to the control unit 13. 3 is a schematic flow diagram of a method executable in the control unit 13 according to a first embodiment of the invention to control the operation of the heater 10 and the fan 12. In step S31, the

Control unit 13 from that the switch 15 detects an opening of the door 2. If this is the case, an internal counter c of the control unit 13 is incremented in step S32 by an increment incr, which may be a constant in a simple embodiment, however, according to a preferred embodiment, directly or indirectly from the temperature T _ext in the environment of the refrigerator and possibly still depends on other sizes. In order to estimate the outside temperature T _ext , a

Ambient temperature sensor may be provided on the refrigeration device outside the insulation layer. However, it is preferable to save the cost of such a sensor and the

Ambient temperature T _ex t estimate indirectly, as will be explained in more detail below.

Another variable that can affect the increment is the duration of the

It is easy to understand that the amount of ambient air entering the storage chamber 3 when the door 2 is opened is greater the longer the door 2 is open and, accordingly, the amount of ambient air of registered water is growing. However, as soon as the air in the storage chamber 3 is completely replaced, the registered amount of moisture increases only slowly. Therefore, it can be assumed in a simple embodiment of the method that with each door opening the air is completely replaced; then only the number of door openings, but not their duration in the increment needs to be considered. A more accurate estimate of the moisture input is achieved if a correspondingly reduced increment is taken as the basis for a short door open which is insufficient for complete air exchange.

If an air humidity sensor is provided in the storage chamber 3, its measured value can be used after the door 2 has been closed again in order to reduce the amount of fuel Quantify water vapor in storage chamber 3 quantitatively and set the increment accordingly.

In step S33, it is checked whether the counter has exceeded a limit value c _ma x which corresponds to a critical water level in the evaporation tray 9. If so, in step S34, the heater 10 and / or the fan 12

turned on, the counter c is reset in step S35, and the process returns to the output. While heater 10 and fan 12 are in operation, the detection of door openings continues with steps S31, S32, S33 and the concomitant re-increment of counter c. Each after a predetermined period of operation, which is empirically determined as sufficient to a the

Threshold c _ma x corresponding amount of water to evaporate and so to reduce the water level in the evaporation tray 9 back to a safe level, heater 10 and fan 12 are turned off again. To the contribution of the waste heat of the compressor 6 to the evaporation in the shell. 9

In the case of on-off control of the compressor 6 by the control unit 13, it may be provided that, when the compressor 6 is in operation, the count value c is reduced by a predetermined decrement at regular time intervals. In the case that the compressor 6 is continuously operated at variable power, the amount of decrement may be proportional or the time interval between two

Decrements are set inversely proportional to the compressor power.

FIG. 4 illustrates a first method for indirectly estimating the

Outside temperature T _ext , which is applicable when the compressor 6 is controlled by the control unit 13 on-off. In step S41, it is waited until the temperature detected by the temperature sensor 14 temperature T of the storage chamber 3 rises above the turn-T _a. Once this is the case, the compressor 6 is turned on and on in step S42

Timers started. In particular, the timepiece can count on the count of

Clock periods of a clock of the control unit 13 based. Once it is determined in step S43 that the temperature of the storage chamber 3 to the switch-off threshold T _from has dropped, the compressor 6 is turned off again, the timer is stopped and since the step S42, elapsed time detected t, and the outdoor temperature T _ext is the basis of a Look-up table estimated in which these as a function of the f (from User adjustable) on threshold T _and the delay time t of the compressor 6 is recorded. The table that describes the relationship between f T _a turn-on threshold, compressor running time t and ambient temperature T _ext, has been previously determined empirically by the manufacturer of the refrigeration unit and stored in a read-only memory of the controller. 13

An estimation of the outside temperature T _ext on the basis of the measured compressor running time t is then possible in a particularly exact manner if the door 2 is not opened during the operation of the compressor 6, between the steps S42 and S44. It can therefore be provided that the method of FIG. 4 terminates without result and a previous estimate of T _{ext is} further used, if an opening of the door 2 is detected during operation of the compressor 6.

Since the difference between the input and switch-off thresholds T _a, T is fixed _from generally is obvious that also the switch-off _of T or

Mean value between the two thresholds T _a, T _of for the estimation of T _ext

could be used.

5 shows the flowchart of a method for estimating the

Ambient temperature T _ext , which is applicable to a refrigerator, the compressor 6 is switchable between different non-vanishing power levels. The

Procedure is repeated at regular intervals. In this method, an upper limit T _max and a lower limit T _{min are set} for the temperature of the storage chamber 3, which should not be exceeded or fallen below for a long time if possible. If it is determined in step S51 when comparing the temperature T of the storage chamber 3 with the upper limit T _max that the temperature T of the storage chamber 3 is above the upper limit T _max , the power PV of the compressor 6 is increased by a predetermined increment in step S52 ε increased.

The time interval between two repetitions of the method is chosen to be large enough to be able to observe an effect of the changed compressor power PV on the temperature T. If the compressor power PV after the boost is sufficient to lower the temperature T, and it is determined in step S51 that the temperature T has fallen below T _max , then the process branches from step S51 to S53, where the temperature T is compared with the lower limit T _min . If this is not exceeded, the compressor power PV remains unchanged, and in turn begins after the predetermined time interval, the process again.

Finally, if the temperature T is less than T _min , in step S54 the

Compressor power reduced by the value ε again. In this way, the compressor power PV continuously adapts to the cooling temperature of the storage chamber 3 that is variable according to the ambient temperature T _ext . Thus, whenever the door 2 of the refrigeration device is opened, in step S55 the ambient temperature T _{ext can be used} as a function of the actual temperature T of the storage chamber 3 or its user set limits T _max , T _min and the compressor power PV a table empirically determined for the respective model of the refrigerator can be estimated.

A method for controlling the operation of heater 10 and fan 12, which does not introduce the moisture input by way of an estimation of the

Ambient temperature, but directly determined, will be explained with reference to Figures 6 and 7. The diagram of FIG. 6 shows two curves of the temperature Tv of the

Evaporator 4 as a function of time t, in each case assumed that at a time tO, the control unit 13 turns on the compressor 6. Before the switch-on time tO, with the compressor 6 switched off, the temperature Tv of the evaporator 4 rises very slowly together with the temperature T of the storage chamber 3. A short time after switching on the compressor 6, the temperature Tv starts to fall. The speed of the temperature drop depends on the humidity in the storage chamber 3 and the rate at which this humidity on the evaporator 4 is reflected as condensation. The fastest drop, shown as curve A in Fig. 6, then arises when the air in the storage chamber 3 is dry and no condensation heat through

Condensation water is released at the evaporator 4. However, when condensation is precipitated, this delays the cooling of the evaporator 4 and results in a curve such as curve B. In practice this means: if between two operating phases of the compressor 6 the door 2 has not been opened and no

Humidity newly arrived in the storage chamber 3, then a temperature profile according to curve A is expected; on the other hand, if the door 2 has been opened, then the curve B results, and the deviation between the two curves allows a conclusion to be drawn about the amount of condensation water separated off at the evaporator. The method illustrated in the flowchart of FIG. 7 utilizes this variable cooling behavior of the evaporator 4 to control the heater 10 and the fan 12: in step S71, the control unit 13 waits until the temperature T of the evaporator 4 stops

Storage chamber 3 has risen above the switch-on threshold T _a . Once this is the case, the compressor 6 is turned on in step S72, and a timer is started to measure the elapsed time t from the switch-on time tO.

In step S73, it is decided whether the door 2 has been open since the last time the compressor 6 was turned on. If not, then it can be assumed that the air in the storage chamber 3 is so dry that the frosting at the evaporator 4 will be negligible in the now commencing phase of operation, and the method advances to step S74 at the temperatures measured during this phase of operation of the evaporator as reference temperatures Tv _ref (t) corresponding to the curve A of FIG. 6.

If, on the other hand, a door opening has taken place, then in step S75 by means of the

Temperature sensor 17, the actual temperature Tv measured at the evaporator at the current time t and compared with the value obtained in an earlier operating phase Tv _ref (t). The difference between the two temperatures Tv (t) and Tv _ref (t) is a measure of the rate at which condensate condenses on the evaporator 4. A count c is incremented by this difference. In step S76, the count value c is compared with a threshold value c _max , and as described with reference to Fig. 3, if the threshold value c _ma x heater 10 and fan 12 are exceeded, the count value c is reset (S77) (S78). The steps S75, S76 are repeated so long until it is determined in step S79 that the storage chamber to the switch-off temperature T _out is cooled. Once this is the case, the process returns to the origin S71.

The repeated summation in step S75 corresponds to a numerical integration of the difference between the two curves B, A of FIG. 6. The value of the integral, c, is proportional to the accumulated amount of condensation water. The time span during which

Heating device 10 and fan 12 remain switched on after step S77, is empirically set so that it is sufficient to the c _ma x corresponding amount of condensation water evaporate. This period obviously depends on the power of the heater 10 and the fan 12, but also on the waste heat capacity of the compressor 6 in operation.

8 shows a flowchart of a second on the evaluation of

Condensation heat based method. The steps of waiting for the on-temperature T to come on _, S81 and to turn on the compressor S82 and start the timer correspond to steps S71, S72. When the compressor has run for a first predetermined time t1, a first measurement of the

Evaporator temperature Tv (t1) instead (S83). A second measurement (S84) takes place at time t2.

In step S85, it is decided whether the door 2 has been open since the last time the compressor 6 was turned on. If not, the measured values obtained in steps S83 and S84 are stored as reference values TV _ref (t1), TV _ref (t2) of the curve A (S86). If yes, then a typical rate of decrease of curve B can be determined from these two measurements. In step S87, the difference between this decrease rate and the decrease rate Tv _ref (t2) -Tv _ref (t1) of the curve A determined at an earlier operating phase of the compressor 6 is calculated at these two points in time. This difference is again representative of the condensation rate at the evaporator 4 and thus for the total amount of moisture contained in the air of the storage chamber 3 and will be reflected in the course of the current operating phase of the compressor 6 at the evaporator 4. Accordingly, the count c is incremented by this difference in S87. The value of c is thus representative of the amount of condensation water at the end of the

Operating phase of the compressor 6 of the evaporation tray 9 would be included, unless the evaporation is promoted by operation of the heater 10 and the fan 12.

In step S88, it is checked whether the count value c has exceeded the threshold c _ma x. If not, in the current operating phase of the compressor, the fan 12 and the heater 10 are not needed, and the process returns to step S81 to await the next compressor operation phase. If c _ma x is exceeded, then

Heating device 10 and fan 12 is turned on (S89) and remain in operation as long as necessary to evaporate the c _ma x corresponding amount of water. Accordingly, the count value is decremented by c _ma x in step S90 before the process returns to step S81

Claims

Refrigerating appliance, in particular household refrigerating appliance, with at least one storage chamber (3) which can be closed by a door (2), an evaporation tray (9) for

Evaporation of condensate discharged from the storage chamber (3) and an auxiliary device (10, 12) which can be switched by a control unit (13) in order to increase the evaporation rate in the evaporation tray (9)

characterized in that the control unit (13) is arranged to detect an opening of the door (2) and to control the operation of the auxiliary device (10, 12) on the basis of the number and / or duration of detected door openings.

Refrigeration appliance according to claim 1, characterized in that the control unit (13) is arranged to further control the operation of the auxiliary device in dependence on the ambient temperature (T _ext ).

Refrigerating appliance according to claim 2, characterized by an ambient temperature sensor connected to the control unit.

Refrigerating appliance according to claim 2, characterized in that it has a

intermittently operated compressor (6) and in that the control unit (13) is arranged to estimate the ambient temperature (T _ext ) based on the duration (t) of an operating phase of the compressor (6) (S42-S44).

Refrigeration appliance according to claim 2, characterized in that it comprises a compressor (6) which is operable to hold the storage chamber (3) at a target temperature with variable power, and that the control unit (13) is adapted to the ambient temperature based on the performance of Estimate compressor (6) (S55).

Refrigerating appliance according to one of the preceding claims, characterized in that it comprises a humidity sensor for detecting the humidity in the

Storage chamber and the control unit is adapted to take into account the measured humidity in controlling the operation of the auxiliary device.

7. Refrigerating appliance according to one of the preceding claims, characterized in that it comprises an evaporator (4) for cooling the storage chamber (3) and one to the evaporator (4) for detecting the temperature (Tv) arranged temperature sensor (17) and that the control unit (13) is arranged to take into account the time course of the evaporator temperature (Tv) in controlling the operation of the auxiliary device (10, 12) (S73-S75, S83-S87).

8. Refrigerating appliance according to claim 7, characterized in that the control unit (13) is set up, the deviation of the time derivative of

Evaporator temperature from a reference value (S85).

9. Refrigerating appliance according to claim 7, characterized in that the control unit (13) is adapted to integrate the difference between a measured and an expected temperature of the evaporator (S73).

10. Refrigerating appliance according to one of the preceding claims, characterized in that it has a defrost heater and that the control unit is adapted to operate the auxiliary device together with the defrost heater.

1 1. Refrigerating appliance according to claim 1, characterized in that the control unit is set up at each door open a count size (c) to change an increment (S32), based on at least one under door opening duration,

Ambient temperature, compressor running time, compressor power, humidity in the storage chamber and rate of change of the evaporator temperature selected size, and the auxiliary device (10, 12) to operate (S34) when the count size (c) reaches a limit (c _ma x).

12. Refrigerating appliance according to one of the preceding claims, characterized in that the auxiliary device comprises a heater (10) and / or a fan (12).