Patent Publication Number: US-8117853-B2

Title: Method of operating a refrigerator unit and/or freezer unit as well as a refrigerator unit and/or freezer unit operated using such a method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Patent Application No. 10 2008 006 760.1, filed Jan. 30, 2008, and German Patent Application No. 10 2008 016 926.9 filed Apr. 2, 2008, both of which are hereby incorporated by reference in their entirety for all purposes. 
     BACKGROUND AND SUMMARY 
     The present disclosure relates to a method of operating a refrigerator unit and/or a freezer unit having two compartments or more than two compartments which each have at least one opening which is closable by a closure element and through which the compartments can be charged with cold air, with at least one temperature sensor being provided for the indirect or direct detection of the respective actual temperature value. 
     Refrigerator units and/or freezer units are known from the prior art which have a plurality of compartments, with the supply of refrigerated air to the compartments and the air return of heated air from the compartments being controlled by means of air flaps. In this connection, units are known in which an air flap is associated with each compartment with a different temperature. It is furthermore known from the prior art to provide units in which compartments are provided without any lower temperature limitation, for example, freezer parts which are also cooled on the refrigeration demand of another compartment. 
     It is the underlying object of the present disclosure to further develop a method of the initially named kind such that the setting of the temperatures in the compartments takes place in a particularly energy efficient manner. 
     This object is solved in accordance with the disclosure by a method for the operation of a refrigerator unit and/or a freezer unit having two compartments or more than two compartments which each have at least one opening which is closable by a closure element and through which the compartments can be charged with cold air, with at least one temperature sensor being provided for the indirect or direct detection of the respective actual temperature value of the compartments. 
     Provision is made in accordance with this that a temperature value (closing value) is defined for a plurality of the compartments or for all of the compartments, that the compartment with the lowest difference between the actual temperature value and the closing value (temperature difference) is determined, and that the closure element of this compartment is closed until its temperature difference is the same as or larger than the temperature difference of a compartment having a larger temperature difference, in one example the compartment having the next larger temperature difference. It is, for example, feasible that, at a specific temperature value above the closing value, the temperature differences of the compartments with an opened closure element are compared with one another and that the closure element of the compartment is thereupon closed in which the lowest temperature difference is present, that is, the smallest interval between the actual temperature value and the closing value. Due to the fact that the closure element of this already comparatively cold compartment is already closed, the total cold air is now supplied to the remaining compartments with an open closure element, which has the result that these undergo a relatively fast cooling and the comparatively cold compartment does not become too cold. The closure element of the named compartment is closed for so long until it is found that its temperature difference is the same as or larger than that of another compartment. Provision is preferably made that the respective compartment with the originally lowest temperature difference is opened by opening the closure element if its temperature difference is equal to or larger than the actual temperature difference value to the closing value of the compartment having the next larger temperature difference of actual value to closing value. The hysteresis can amount to 0.5 K, for example. 
     The present disclosure furthermore relates to a method of operating a refrigerator unit and/or a freezer unit having at least one evaporator as well as having two compartments or more than two compartments which each have at least one opening which is closable by a closure element and through which the compartments can be charged with cold air, with at least one temperature sensor being provided in the respective compartments for the indirect or direct detection of the actual value of the temperature, the method comprising. Provision is accordingly made that a temperature range (opening range) is defined for a plurality of compartments or for all of the compartments of the unit, that the evaporator is activated when the temperature in one of the compartments reaches or exceeds the upper value of the opening range and/or when the evaporator activation temperature is reached or exceeded. Provision is furthermore made that the closure element of this compartment as well as the closure elements of the further compartment or compartments are opened when their actual temperature values are within the respective opening range. 
     Provision is made in this case that the closure element of the compartment is opened when its temperature has reached or already exceeded the upper limit of the opening range. Furthermore, the closure elements of the compartments are opened whose actual temperature value is within the respective opening range. 
     The term “temperature sensor” is to be given a wide interpretation and includes any conceivable means suitable to draw conclusions on the temperature in the compartment. In one specific example, a respective one or a plurality of temperature sensors are provided in each or in some of the compartments. In another specific example, alternatively or additionally, a temperature sensor is provided which detects the evaporator temperature or a different temperature via which conclusions can be drawn on the temperatures in the compartments. 
     Provision is made in a further embodiment of the disclosure that the determination of the compartment having the lowest temperature difference and the closing of its closure element only takes place when the actual temperature value has reached or fallen below a predetermined interval to the closing value. It is conceivable to determine the differences between the actual temperature values and the respective closing values for all the compartments. If it is found that the interval of the actual temperature value from the closing value has reached or fallen below a specific interval, for example 4 K, for a compartment, provision can be made that the temperature differences, that is, the differences between the respective actual temperature values and the closing values, of the compartments having open closure elements are compared with one another. Then the closure element of the compartment with the lowest temperature difference is closed. 
     Provision is made in a preferred embodiment of the disclosure that the unit has at least one fan by means of which cold air can be introduced into the compartments through the named closable openings. 
     The unit can have at least one refrigerated air passage, with the fan being arranged such that it moves the air through the refrigerated air passage into the compartment or compartments. The refrigerated air passage can, for example, be bounded by a vertical partition plate which is located in the rear region of the unit and which can, for example, form the rear wall of the compartment or compartments. 
     Provision is made in a further embodiment of the disclosure that the fan is activated when the evaporator temperature reaches or falls below a limit value. It is, for example, conceivable that the fan is activated when the evaporator temperature is below the temperature of the compartment whose temperature has reached or exceeded the upper value of the opening range by a predetermined value, for example 1 K. 
     Provision is made in a further embodiment of the disclosure that the closure elements of the compartments are opened when their actual temperature value reaches or exceeds the lower region of the opening range. If compartments are accordingly present whose actual temperature values are below the lower limit of the opening range, their closure elements first remain closed. Provided the actual temperature values reach the lower region of the opening range, the associated closure elements are opened so that the compartments are charged with cold air. 
     Provision is made in a further embodiment of the disclosure that the evaporator is deactivated when the actual temperature values of all the compartments have reached their respective closing values. 
     If this is the case, provision can additionally be made that the speed of the fan is reduced with respect to the actual refrigeration operation. 
     Provision can furthermore be made that the closure elements of the compartments whose closure elements are opened at times or permanently during the cooling procedure are now opened when the actual temperature values of all the compartments have reached their respective closing values. In this case, cold air is introduced into the compartments at a reduced speed of the fan. In this manner the residual cold can be utilized and the standing time shortened. Provision can furthermore be made that the fan is finally deactivated when the evaporator temperature reaches or exceeds a limit value. 
     Provision can finally be made that the respective closure element is closed as soon as the respective actual temperature value or a value characteristic for the temperature reaches a desired value or exceeds it by a preset amount. 
     Provision is made in a further embodiment of the disclosure that a desired temperature value is presettable for at least one of the compartments and that the opening range and/or the closing value of the other compartments depend on the desired temperature value. If, for example, with an unchanged desired value setting of the compartment arranged at the top, the desired value setting of a compartment arranged thereunder is changed in the direction of “cold”, the opening range and the closing value of the closure element of the upper compartment are corrected in the direction “warm” in order to compensate the increased cooling by the return air flow from the lower compartment. 
     The present disclosure furthermore relates to a refrigerator unit and/or a freezer unit having, comprising two or more compartments which each have at least one opening which is closable by a closure element and through which the compartments can be charged with cold air; at least one temperature sensor positioned in each of the two or more compartments, the temperature sensor providing indirect or direct detection of an actual temperature value of the respective compartments; and a control and/or regulation unit which is configured to determine a temperature value for each of the two or more compartments, determine a compartment with the lowest temperature difference between an actual temperature value and the determined temperature value; and close the closure element of this determined compartment until its temperature difference is the same as or larger than a temperature difference of another compartment having a larger temperature difference. 
     Further details and advantages of the disclosure will be explained in more detail with reference to an embodiment shown in the drawing. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1  shows a refrigerating unit in accordance with the present disclosure. 
         FIG. 2  shows an example method of operation, 
     
    
    
     DETAILED DESCRIPTION 
     The refrigerating and/or freezing unit  8  in accordance with the embodiment shown here has a refrigerating part  10  arranged at the top as well as a compartment (“BioFresh, variable) arranged thereunder and a compartment  30  (“BioFresh, fixed) arranged thereunder. This arrangement is only by way of example. Other arrangements of the compartments are also conceivable. A fan is marked by the reference numeral  40  which extracts air from the compartment  10  and conveys it into the refrigeration air passage  50  as indicated by the dashed line arrows. The evaporator  60  with the evaporator sensor  62  is located therein. The evaporator sensor  62  emits a temperature value characteristic for the temperature of the evaporator  60 . The unit  8  further includes a refrigeration circuit  80  having a compressor  82  coupled to the evaporator  60 . 
     The refrigerating unit  8  may further include a control system  70 . Control system  70  is shown receiving information from a plurality of sensors  74  (such as sensors  62 ,  12 ,  22 ,  32 ) and sending control signals to a plurality of actuators  76  (such as fan  40 , closure elements  14 ,  24 ,  34 , etc.). The control system  70  may include a control/regulation unit  72  (controller). The controller may receive the input data from the various sensors, process the input data according to various routines, and trigger the actuators in response to the processed input data based on instructions or code programmed therein corresponding to one or more routines or methods. Example control routines and methods are described herein (e.g., with regard to  FIG. 2 ). In one example, the routines and/or methods are embodied in instructions and/or code on computer readable storage media included in the controller  72 . 
     As can further be seen from  FIG. 1 , a temperature sensor  12 ,  22 ,  32  is located in each of the compartments. 
     Furthermore, each of the compartments  10 ,  20 ,  30  can be connected to the refrigeration air passage  50  via an air flap or any other closure element  14 ,  24 ,  34 . When the air flap  14 ,  24 ,  34  is open, air is accordingly introduced from the refrigeration air passage  50  into the respective compartment  10 ,  20 ,  30 .  FIG. 1  shows an example airflow configuration via arrows in which the fan is operating and each of air flaps  14 ,  24 , and  34  are open. As described herein, various other flap configurations may be used to adjust airflow differently among the compartments. 
     As can furthermore be seen from  FIG. 1 , the air which has flowed through the compartments  10 ,  20 ,  30 , is led back through the actual useful capacity of the unit to the fan  40 . In this way, a useful capacity loss is avoided by separately provided air passages for the returning of already heated air. The air return of all temperature zones or compartments rather takes place together in the useful capacity zone in accordance with the depicted example. 
       FIG. 2  shows an example method  200  for controlling operation of the refrigerator unit. The refrigerator unit in accordance with the present disclosure has an evaporator and a fan and serves for the control or regulation of the temperatures in the individual compartments which takes place independently of one another. 
     To minimize the compressor running times, the times at which the air flaps  14 ,  24 ,  34  are open are synchronized in dependence on the respective cold demands. 
     Any temperature influence due to the air return through the useful capacity zone can be prevented by a corresponding control/regulation of the opening and closing times of the respective air flaps  14 ,  24 ,  34  associated with the individual temperature zones or compartments  10 ,  20 ,  30 . 
     Provision is made in the embodiment shown here, e.g., via the control system, that the compartments  10 ,  20 ,  30  are each operated at a specific desired temperature value or in a desired temperature value range, with the desired values or the desired value ranges being able to differ from one another. 
     The control of the air flaps  14 ,  24 ,  34  takes place via a corresponding control member which is in turn connected to the control/regulation unit. As noted above, it receives temperature values from the temperature sensors  12 ,  22 ,  32 . 
     An opening range and a closing value are defined for each of the compartments  10 ,  20 ,  30 . The opening range should allow a proportion of parallel operation of the individual compartments which is as high as possible and thus an energy-saving operation. 
     The temperature control or temperature regulation is as follows: 
     At  202 , the compressor, evaporator, and fan are operated according to operating conditions. For example, as soon as one of the three temperature sensors  12 ,  22 ,  32  exceeds the upper value of the opening range associated with the respective compartment and the evaporator sensor has reached its activation value, the evaporator  60  is activated, which in other words means that the refrigerant circuit, optionally with the compressor, magnetic valve, etc., is set into operation. If the evaporator sensor  62  reports a temperature value of, for example, 1 K below the temperature value of the compartment whose temperature has exceeded the opening range associated with the compartment, the fan  40  is switched on at a high speed and the corresponding air flap of the compartment is opened. If, for example, the temperature value in the compartment  10  has exceeded the upper limit of the opening range and if the evaporator sensor  62  has reached the activation value, the evaporator is activated. If the evaporator  60  is sufficiently cold, if the temperature measured with the temperature sensor  62  is, for example, 1 K below the temperature measured with the temperature sensor  12 , the fan  40  is switched on and the air flap  14  is opened so that the compartment  10  is charged with cold air. 
     The same naturally applies accordingly to the other compartments, provided that their actual temperature values have exceeded the upper values of the respective opening ranges. 
     At  204 , the method determines a desired opening temperature range and closing value temperature for each compartment. 
     At  206 , the flaps are adjusted (e.g., opened, closed, or made more or less open/closed) based on the determined and actual temperatures. For example, if the temperature values of the other compartments are within the respective opening range, their associated air flaps (in the aforesaid example thus the air flaps  24  and  34 ) are also opened. If compartments are present whose actual temperature values are not (yet) in the respective opening range, their air flaps remain closed until the actual temperature value has reached the lower value of the associated opening range. The associated air flap is then opened. 
     It is conceivable in the embodiment shown here that all the closure elements or air flaps  14 ,  24 ,  34  are open during the refrigerating procedure so that all the compartments  10 ,  20 , are supplied with cold air from the refrigeration air passage  50  through the openings, as shown in  FIG. 1 . 
     At  208 , from a specific interval (e.g. 4 K) before the respective closing value, the temperature differences, that is, the differences from the actual temperature value to the closing value of the compartments  10 ,  20 ,  30  whose closure elements  14 ,  24 ,  34  are open are compared with one another. In this respect, the compartment with the lowest temperature difference from the actual temperature value and the closing value is determined and its closure element is closed. If, for example, the difference between the actual temperature value and the closing value in the compartment  30  is lower than in the compartments  10  and  20 , the closure element  34  is closed at  210 . The closure element remains closed for so long until the temperature difference of this compartment is equal to or larger than the temperature difference of the compartment with the next higher temperature difference. If, for example, at a specific time, the temperature difference between the actual temperature value and the closing value in the compartment  30  whose closure element  34  is closed is 5 K and if the compartment  20  has cooled so much that the temperature difference is likewise 5 K or less there, the closure element  34  of the compartment  30  is opened again. 
     Additional operations may also be provided in method  200 , e.g., at  202 . For example, if all the compartments  10 ,  20 ,  30  have reached their closing values, the evaporator  60  is deactivated by switching off the compressor or by connection of a magnetic valve, for instance, and the speed of the fan  40  is set to a lower value. If the air flaps  14 ,  24 ,  34  are closed, they are opened, provided that they were at least partly opened in the phase in which all the compartments have not yet reached their closing values, i.e. in the cooling phase. 
     If the evaporator  62  reports a specific temperature value, for example, 5° C., the fan  40  is completely switched off. 
     In one example, the flaps  14 ,  24 ,  34  are closed as soon as the corresponding temperature sensor  12 ,  22 ,  32  reports a temperature which corresponds to the desired temperature value of the respective compartment and optionally corresponds to a supplement of, for example, 3 K. 
     The evaporator remains deactivated until the evaporator sensor  62  has reached the activation value and/or an air sensor reaches an upper corridor value. 
     Further, the setting of the individual temperature zones influences the opening and closing values of the air flaps associated with the other temperature zones or compartments due to the parallel correction factors defined in steepness. 
     If, for example, with an unchanged desired value setting of the upper compartment  10 , the desired value setting of the compartment  20  is changed downwardly, that is, in the direction of “cold”, the opening and closing values or the opening range and the closing value of the upper compartment  10  are corrected in the direction of “warm” to compensate the increased cooling due to the return air flow from the lower compartment  20 . The reverse naturally applies correspondingly when the desired value setting of a compartment is changed in the direction of “warm”.