EP2694897B1 - A refrigerator and a method for controlling the refrigerator - Google Patents

Description

The present invention relates to a refrigeration device and a method for controlling the refrigeration device. The refrigeration device comprises at least one cold room, which can be closed by at least one door. Furthermore, the refrigeration device comprises a refrigeration cycle which has a compressor and a control device which is suitable for switching on or off the compressor.

A method according to the preamble of claim 1 for controlling a refrigeration device is off DE 10 2009 001 678 A1 known. In the known method, the temperature prevailing in the cold room is first determined and compared in each case with a maximum temperature and a minimum temperature. The compressor is switched on when the temperature exceeds the maximum temperature and switched off when the temperature falls below the minimum temperature. If the temperature is below the maximum temperature and above the minimum temperature, ie between maximum temperature and minimum temperature, then the compressor is switched on alternately during a switch-on period and switched off during a switch-off period. In the known method, the duty cycle and the switch-off are predetermined, that is, the switching on of the compressor and the switching off of the compressor is time-controlled. This refinement has the disadvantage that the switch-on duration and the switch-off duration for a refrigeration device must be predetermined. This can lead, in particular, when the prevailing conditions deviate greatly from the conditions that are foreseen for the refrigeration appliance, that uneven cooling cycles arise. This has the consequence that the temperature in the cold room often exceeds the maximum temperature or falls below the minimum temperature, whereby the efficiency of the refrigerator decreases. In addition, the prediction of the switch-on duration and the switch-off duration has the disadvantage that the switch-on duration and the switch-off duration are to be determined in advance by lengthy test series.

The object of the present invention is to overcome the disadvantages of the known from the prior art method, and thus to improve the known method for controlling a refrigeration device.

To solve this problem, a method according to claim 1, and a refrigerator according to claim 10 is proposed.

Advantageous embodiments of the method according to the invention are described in claims 2 to 9. Advantageous embodiments of the refrigerator according to the invention are described in the claims 11 and 12.

The inventive method for controlling a refrigeration device is characterized in particular by the fact that the control of the refrigeration device is dynamically adjusted by the temperature-dependent control of the switch-off. This means that longer test series for setting the control behavior can be dispensed with.

The inventive method further has the advantage that the control behavior is optimized in particular for different ambient and compartment temperatures. Furthermore, the method according to the invention achieves an efficiency optimization of the operated device.

Preferably, the difference between the maximum temperature and the minimum temperature is between 0.1 ° and 10 °, preferably between 0.2 ° and 2 °, more preferably between 0.5 ° and 1 °.

In a preferred embodiment of the method according to the invention, the temperature-dependent control of the switch-off only takes place in the presence of constant conditions. This embodiment has the advantage that the control behavior of the refrigeration device is not adapted to short-term changing conditions, whereby the control behavior is optimized in the presence of these constant conditions.

Preferably, the method according to the invention is characterized in that the presence of constant conditions comprises that, over a time interval, the door remains closed and / or an ambient temperature remains approximately constant and / or no defrosting phase occurs. This embodiment has the advantage that disturbing external influences are not included in the adaptation of the control of the refrigeration device, whereby the control behavior for long-term conditions is improved. Such external influences may be, for example, a strongly changing ambient temperature or an internal temperature which, in the cooling compartment, adjusts itself briefly to the outside temperature by opening the door. A defrosting phase can also influence the temperatures in the interior of the refrigeration device in such a way that a sensible temperature-dependent adaptation of the control can not take place. For this reason, it is advantageous to make no temperature control during a defrosting phase.

Alternatively, the presence of constant conditions can be determined from the control behavior of the control device. In particular, a cyclical recurrence of the control behavior over time indicates the presence of more constant conditions. It does not matter whether the control behavior is optimized with regard to the existing environmental conditions or not. If the control behavior over the time interval is constant and / or cyclically recurrent, conclusions about the existence of constant conditions can be drawn.

Advantageously, the method according to the invention is further characterized in that the time interval is between 10 minutes and 12 hours, preferably between 30 minutes and 6 hours, more preferably between 1 hour and 5 hours. This embodiment has the advantage that it is excluded that short-term changes in temperature are used as a basis for adapting the control of the refrigeration device. Thus, for example, when filling the refrigerator with a relatively large amount of comparatively warm liquid, such as uncooled beverages, the temperature within the refrigerator increases for a certain period of time. If the control behavior of the refrigeration device would now adapt to these conditions, the efficiency of the refrigeration device would also be less adapted in the case of constant conditions. Accordingly, the adjustment of the control of the refrigeration device is performed only at present constant conditions.

In a preferred embodiment of the method according to the invention, the regulation of the switch-off duration takes place in that the switch-off duration is reduced when the maximum temperature is exceeded. Furthermore, the method is preferably characterized in that the regulation of the switch-off duration takes place in that the switch-off duration is increased when the minimum temperature is undershot.

This embodiment has the advantage that the temperature in the interior of the refrigeration device as possible within the temperature interval, which is limited by the minimum temperature and the maximum temperature remains. This increases the energy efficiency. The embodiment further offers the advantage that the switch-off duration is automatically selected so that the temperature inside the refrigeration device remains as long as possible within the temperature interval at constantly constant conditions. In addition, it is thus possible to dispense with the time-consuming predetermination of the switch-off duration for the given refrigeration appliance.

As an alternative to the embodiment described above, it would also be possible to increase the switch-on duration instead of reducing the switch-off duration. This would also lead to an improved control behavior of the refrigerator. However, this embodiment has the disadvantage that the optimal duty cycle, or running time, of the compressor, which can be determined in advance for a given refrigeration cycle, is left. In this respect, to optimize the control of the refrigeration appliance, the change of the switch-off duration with respect to the change in the switch-on duration is to be preferred.

In a preferred embodiment, the method according to the invention is characterized in that, after reducing and / or increasing the switch-off duration, a flag is set in order to prevent the switch-off duration from being reduced and / or increased once again and that the flag after expiration a blocking period is cleared to allow the off period is reduced again and / or increased. Preferably, the lockout time may be determined by a number of compressor run times. A compressor running time results from the sum of the switch-off duration and the switch-on duration.

This embodiment has the advantage that the control is better adapted to long-term changes in the environment.

The blocking time is preferably at least two transit times. Further preferably, the blocking time is between two and twenty terms. Further preferably, the blocking time is between two and ten terms.

In a preferred embodiment, the method is characterized in that the duty cycle is between 30 seconds and 30 minutes, preferably between 1 minute and 10 minutes, more preferably about 4 minutes. Furthermore, the switch-off duration is preferably between 1 minute and 60 minutes, preferably between 2 minutes and 20 minutes, more preferably about 8 minutes.

Advantageously, when the maximum temperature is exceeded, the switch-off duration is reduced by a constant amount, and increased by the constant amount when the minimum temperature is undershot. The constant amount is between 5 seconds and 5 minutes, preferably between 10 seconds and 2 minutes, more preferably about 0.5 minutes.

The refrigeration device according to the invention for carrying out the method according to one of claims 1 to 9 comprises at least one cold room, which is closed by at least one door, a refrigeration cycle having a compressor, a control device which performs the control according to one of the claims 1 to 9 , and a temperature sensor which is suitable for determining the temperature prevailing in the cold room.

The refrigerator according to the invention makes use of the advantages of the method according to the invention. Preferably, the refrigeration device according to the invention comprises a device which is suitable for determining whether constant conditions prevail.

Further preferably, the device comprises an outside temperature sensor which is suitable for measuring an ambient temperature. Preferably, the device comprises a door sensor adapted to determine if the door is open. Further preferably, the device is adapted to determine whether a defrost phase occurs.

Fig. 1:

eine schematische Ansicht eines erfindungsgemäßen Kältegeräts;

Fig. 2:

ein Diagramm, das den Verlauf der in dem Kälteraum des Kältegeräts gemessenen Temperatur und den Verlauf der durch den Verdichter erbrachten Leistung, im Laufe der Zeit für ein herkömmliches Kältegerät wiedergibt;

Fig. 3

ein Diagramm, das den Verlauf der in dem Kälteraum des Kältegeräts gemessenen Temperatur und den Verlauf der durch den Verdichter erbrachten Leistung, im Laufe der Zeit für ein erfindungsgemäßes Kältegerät wiedergibt.

Further advantages of the method and the refrigerating appliance according to the invention will become apparent from the preferred embodiment described below. In the drawings, which only schematically illustrate the exemplary embodiment, illustrate in detail:

Fig. 1:

a schematic view of a refrigerator according to the invention;

Fig. 2:

a diagram showing the course of the measured in the cold room of the refrigerator temperature and the course of the power provided by the compressor, over time for a conventional refrigeration appliance;

Fig. 3

a diagram showing the course of the temperature measured in the cold room of the refrigerator and the course of the power provided by the compressor over time for a refrigeration device according to the invention.

FIG. 1 shows a schematic view of a refrigeration device 10. The refrigeration device 10 includes a cold room 14, which is closed by a door 12, a refrigeration circuit 20 and a control device 30. The refrigeration cycle 20 includes in particular a compressor 22. A temperature sensor 32 of the control device 30 is inside arranged the cold room 14 and measures the temperature T of the air in the cold room 14.

In a preferred embodiment, the control device 30 of the refrigeration device 10 has a door sensor 34, which determines whether the door 12 of the refrigeration device 10 is open or closed. Accordingly, the door sensor 34 can determine whether the air in the cold room 14 is prevented from mixing with the air outside the refrigerator 10. A closed door 12 thus contributes to constant temperatures in the interior of the cold room 14.

The control device 30 of the refrigeration device 10 may have an outside temperature sensor 36. Suitably, the outside temperature sensor 36 is arranged on the outside of the refrigeration device 10. Preferably, the outside temperature sensor 36 of the control device 30 is arranged such that a possible heat release of an evaporator of the refrigeration cycle 20 does not affect the measurement of the outside temperature.

FIG. 2 shows a diagram representing the temperature profile and the performance of a compressor 22 of a refrigeration device 10, wherein the control behavior is not yet optimally adapted to the prevailing environmental conditions. The course of the temperature T within the cooling space 14 of the refrigeration device 10 is reproduced in the lower area of the diagram. The temperature T has strong fluctuations due to the irregular control behavior.

The temperature T is within the interval T _min to T _max, the compressor 22 of the refrigerating device 10 of the invention is _an on and off time t off during an _out alternately t during a duty cycle.

If the temperature T exceeds the temperature T _max , then, if no flag is set yet, the flag is set and the switch-off duration t _off is reduced for future cycles. If a flag has already been set, the switch-off duration t _{off is} retained. Markers are cleared after a predefined number of cycles.

If the temperature T falls below the minimum temperature T _min , the compressor 22 is switched on and the switch-off duration t _out is increased by the same constant value if no flag is set, and such a flag is then set. The flag is cleared after a run of a predetermined number of cycles.

If the temperature T from a temperature above the maximum temperature T _max, so that the temperature T is again in the interval between T _min and T _max, the compressor 22 is initially the duration t _of an off-off. If the temperature T rises from a temperature below the minimum temperature T _min to a temperature which is within the minimum temperature T _min and the Maximum temperature T _{max is} defined interval, it is switched off for the duration of the switch-off t _from the compressor 22.

As can be seen in particular from the curve representing the compressor performance, the existing constant conditions for the exemplary embodiment are expressed by a regular and recurring control behavior (3 short peaks followed by a long peak power).

FIG. 3 indicates an optimized control behavior of a refrigeration device 10 according to the invention. With the optimized control behavior, the duty to remain _a t and the off time t _from the passage of time equal in length. Also, the temperature T remains relatively constant, and moves within the interval between the minimum temperature T _min and the maximum temperature T _max .

This in FIG. 3 reproduced control behavior has been adjusted according to the invention itself, so that the predetermined temperature interval is not left and the switch-off t _off and the _switch-ta remain constant for a long time.

Like that in FIG. 2 reproduced diagram illustrates, the compressor 22 is three times in succession for a duration t _a is turned on and a switched-off _from t off. Following this, a longer activation of the compressor 22, which t a duty follows _a beyond. This is due to the fact that the temperature T has increased beyond the maximum temperature T _max . As the FIG. 2 can be seen further, the control pattern described follows again after a prolonged switch-off. This regular and recurring control behavior thus indicates the existence of constant conditions. Also in FIG. 3 The diagram reproduced shows a repetitive control behavior of the control device 30 FIG. 3 also deduce that constant conditions prevail. A regulation of the switch-off duration t _off can accordingly take place to improve the control behavior of the controller 30

The method according to the invention for a refrigeration device enables the efficiency of the refrigeration device to be optimized. Furthermore, the inventive method is optimal Regulator settings available, regardless of the existing ambient and compartment temperatures. In addition, the trial and development effort is reduced by the inventive method. The method according to the invention can also be implemented cost-effectively, on a software basis.

LIST OF REFERENCE NUMBERS

10

The refrigerator

12

door

14

cold room

20

Refrigeration circuit

22

compressor

30

control device

32

temperature sensor

34

door sensor

36

Outdoor temperature sensor

T

temperature

T _max

maximum temperature

T _min

minimum temperature

_ta

duty

t _off

off time

Claims (12)

1. Method for controlling a refrigerator (10) including at least one refrigeration compartment (14) which can be closed by at least one door (12), a refrigerant circuit (20) comprising a compressor (22) and a control apparatus (30) which is suited to switching the compressor (22) on or off, having the following method steps:

   a) determining the temperature (T) prevailing in the refrigeration compartment (14);

   b) comparing the temperature (T) with a maximum temperature (T_max );

   c) comparing the temperature (T) with a minimum temperature (T_min );

   d) switching the compressor (22) on if the temperature (T) exceeds the maximum temperature (T_max );

   e) switching the compressor (22) off if the temperature (T) falls below the minimum temperature (T_min );

   f) alternately switching the compressor (22) on during a switch-on duration (t_on ) and switching the compressor (22) off during a switch-off duration (t_off ) if the temperature (T) lies below the maximum temperature (T_max ) and above the minimum temperature (T_min ); characterised by the following method step:

   g) changing the switch-off duration (t_off ) as a function of the temperature (T).
2. Method according to claim 1, characterised in that the temperature-dependent change in the switch-off duration (t_off ) only occurs if constant conditions exist.
3. Method according to claim 2, characterised in that the existence of constant conditions includes the door (12) remaining closed and/or an ambient temperature remaining approximately constant and/or no thaw phase occurring during a time interval.
4. Method according to claim 3, characterised in that the time interval amounts to between 10 minutes and 12 hours, preferably between 30 minutes and 6 hours, further preferably between 1 hour and 3 hours.
5. Method according to one of claims 1 to 4, characterised in that the change in the switch-off duration (t_off ) takes place such that the switch-off duration (t_off ) is reduced if the maximum temperature (T_max ) is exceeded.
6. Method according to one of claims 1 to 5, characterised in that the change in the switch-off duration (t_off ) takes place such that the switch-off duration (t_off ) is increased if the minimum temperature (T_min ) is not reached.
7. Method according to one of claims 1 to 6, characterised in that a marker is set after reducing and/or increasing the switch-off duration (t_off ) in order to prevent the switch-off duration (t_off ) from being reduced again and/or increased and that the marker is deleted after an off-period has elapsed in order to allow the switch-off duration (t_off ) to be reduced and/or increased again.
8. Method according to one of claims 1 to 7, characterised in that the switch-on duration (t_on ) amounts to between 30 seconds and 30 minutes, preferably between 1 minute and 10 minutes, further preferably approx. 4 minutes.
9. Method according to one of claims 1 to 8, characterised in that the switch-off duration (t_off ) amounts to between 1 minute and 60 minutes, preferably between 2 minutes and 20 minutes, further preferably approx. 8 minutes.
10. Refrigerator for executing the method according to one of claims 1 to 9, including:

    at least one refrigeration compartment (14) which can be closed by at least one door (12);

    a refrigerant circuit (20) comprising a compressor (22);

    a control apparatus (30) which executes the control according to one of the method claims 1 to 9, and

    a temperature sensor (32) which is suited to determining the temperature (T) prevailing in the refrigeration compartment (14).
11. Refrigerator according to claim 10, characterised by a facility which is suited to determining whether constant conditions prevail.
12. Refrigerator according to claim 11, characterised in that the facility includes an exterior temperature sensor (36) which is suited to measuring an ambient temperature and/or a door sensor (34) which is suited to determining whether the door (12) is open and/or that the facility is suited to determining whether a thaw phase is occuring.

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