EP1180652B1 - Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur - Google Patents

Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur Download PDF

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Publication number
EP1180652B1
EP1180652B1 EP20000117310 EP00117310A EP1180652B1 EP 1180652 B1 EP1180652 B1 EP 1180652B1 EP 20000117310 EP20000117310 EP 20000117310 EP 00117310 A EP00117310 A EP 00117310A EP 1180652 B1 EP1180652 B1 EP 1180652B1
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EP
European Patent Office
Prior art keywords
defrost
evaporator
duration
temperature
compressor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP20000117310
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German (de)
English (en)
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EP1180652A1 (fr
Inventor
Mike Hirsch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ranco Inc of Delaware
Robertshaw US Holding Corp
Original Assignee
Ranco Inc of Delaware
Ranco Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Ranco Inc of Delaware, Ranco Inc filed Critical Ranco Inc of Delaware
Priority to EP20000117310 priority Critical patent/EP1180652B1/fr
Priority to DE2000630971 priority patent/DE60030971T2/de
Priority to TR2001/02371A priority patent/TR200102371A2/xx
Publication of EP1180652A1 publication Critical patent/EP1180652A1/fr
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Publication of EP1180652B1 publication Critical patent/EP1180652B1/fr
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/002—Defroster control
    • F25D21/008—Defroster control by timer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/15—Power, e.g. by voltage or current
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D2500/00—Problems to be solved
    • F25D2500/04—Calculation of parameters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D2700/00—Means for sensing or measuring; Sensors therefor
    • F25D2700/02—Sensors detecting door opening
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D2700/00—Means for sensing or measuring; Sensors therefor
    • F25D2700/14—Sensors measuring the temperature outside the refrigerator or freezer

Definitions

  • the present invention relates to a controller and a method for controlling a defrost operation in a refrigerator, according to the preamble of claims 1 and 22.
  • a controller and a method of this kind are known from DE 29 45 691 and US 5 440 893.
  • a controller for defrosting the evaporator of a refrigerator which adaptively controls a defrost operation for melting ice accumulated on the evaporator during a refrigeration period, that is during a period of normal operation of the refrigerator to maintain a food compartment of the refrigerator at a desired temperature. From this document it is known that when the compressor of the refrigerator is switched off to start a defrost operation, the time taken for the evaporator to reach a preset temperature above 0°C is approximately proportional to the amount of ice accumulated on the evaporator during the preceding refrigeration period.
  • Heater means are provided for supplying heat to the evaporator during the defrost operation.
  • the known controller delays a next defrost operation by a factor dependent on the time the evaporator takes to reach the preset temperature during the defrost operation.
  • the known controller measures the duration of a defrost time interval until the evaporator has reached the preset defrost temperature. If this duration is less than a predetermined target defrost duration, the known controller extends the next refrigeration period. If the defrost duration is larger than the target defrost duration, the known controller reduces the next refrigeration period and hence advances the beginning of the next defrost period. In this way, the known controller saves energy by carrying out less defrost operations in conditions of low ice formation rate. Similarly, if the ice formation rate is high, the frequency of defrost operations is increased thus ensuring that the evaporator stays largely ice free and hence operates at high efficiency.
  • the time taken by the evaporator to reach the preset defrost temperature above 0°C, signaling the end of a defrost operation is influenced not only by the amount of ice on the evaporator when an additional source of thermal energy, e.g. an electric heater, is used for accelerating the defrost operation.
  • the duration of the defrost time interval until the evaporator has reached the preset defrost temperature also depends on the amount of heat supplied by the additional source of energy per time unit to the evaporator during the defrost operation.
  • the energy that is supplied per time unit by the additional source of thermal energy in turn depends on the present condition of the power supply that feeds the thermal energy source.
  • Fig. 1a shows a typical behavior of the evaporator temperature T over time in a first condition A when the power supply of the refrigerator is weak, e.g. the mains voltage is low, and in a second condition B when the power supply is strong, e.g. the mains voltage is high. From Fig.
  • the known controller is furthermore unable to take into account the thermal dispersion through the refrigerator appliance insulation. Also, it initiates a defrost immediately after the calculated refrigeration period time limit has expired.
  • Fig. 1b shows a first situation A that the refrigeration period ends with the evaporator temperature having a comparatively high value.
  • Fig. 1b furthermore shows a situation B where the refrigeration period ends with the evaporator temperature being at a comparatively low value.
  • the total amount of time required for the evaporator to reach the preset defrost temperature differs in both situations A and B.
  • situation A the known controller will set the next refrigeration period time limit different than in situation B, due to the timing error in the defrost time interval. This again results in refrigeration periods less than optimum and in an increased energy consumption of the refrigerator.
  • the known controller always reacts to past icing conditions on the evaporator.
  • the accumulation of ice on the evaporator generally results from opening the refrigerator door. If after a defrost operation a user frequently opens the refrigerator door in the subsequent refrigeration period, the amount of ice actually accumulating on the evaporator may differ substantially from what was detected during the previous defrost operation.
  • the known controller is not able to react appropriately to this situation. It cannot prevent that in the course of the current refrigeration period with many door openings a lot of ice accumulates hence lengthening the time taken for the evaporator to reach the preset defrost temperature. This will cause the known controller to shorten the next refrigeration period even if the rate of ice accumulation returns to normal.
  • an automatically defrosting refrigeration apparatus which includes a refrigerant evaporator, a heater for defrosting the evaporator, defrost initiating means for initiating a defrost operation and timer means for measuring a defrost time required to carry the defrost operation, in which the accumulated compressor run time interval between defrost operations is controlled based on a difference between two successive defrost times.
  • the defrost time is monitored by monitoring the voltage to the defrost heater via a voltage detection circuit.
  • this object is solved as defined in claims 1 and 22.
  • a power supply condition of the refrigerator is detected and the target defrost duration is adjusted in accordance with the detected thermal dispersion.
  • the detected power supply condition can be the mains voltage or the current through the electrical heater when in operation. It would however be feasible to detect the present power supply condition for instance by means of measuring the temperature of the electrical heater means or even its temperature dependent electrical resistance when in the energized state.
  • the present invention allows to adapt the duration of the refrigeration periods to the actual amount of ice accumulated on the evaporator essentially independent from the condition of the mains to which the refrigerator is connected.
  • the present invention therefore improves the energy efficiency of a refrigerator with an adaptive defrost function in an unstable mains voltage environment.
  • the optimum target defrost time can be determined during development testing of the refrigerator appliance at a number of different power supply conditions and preferably also at a number of different ambient temperatures which the appliance can be expected to see during its use.
  • These various target defrost durations in association with the various mains voltages and ambient temperatures can be stored in a memory and can be used at the end of each defrost to calculate a new value for the subsequent refrigeration period.
  • fuzzy logic can be used.
  • the target defrost duration can be calculated through a mathematical formula as a function of the detected power supply condition and preferably of the detected thermal dispersion.
  • a nominal target defrost duration of 30 minutes at 250 V mains voltage feeding the heater can be adjusted by an amount proportional to the square of the mains voltage deviation from the 250 V.
  • a linear approximation can be sufficient.
  • the target defrost duration is calculated as a function of the thermal dispersion with a linear term and/or a quadratic term.
  • a controller according to the present invention is preferably implemented using a microprocessor, and said look up table or said calculation routine of the target defrost duration can be stored in the microprocessor read-only memory or similar non volatile storage medium. The resulting programming complexity is well within the capabilities of a low-cost 4-bit or 8-bit microprocessor.
  • the controller according to the present invention measures the refrigeration period in terms of compressor running time rather than in terms of total time between defrost operations.
  • the amount of ice accumulated on the evaporator can be regarded as approximately proportional to the accumulated running time of the compressor. It is, however, possible to use the total time, that is ON periods and OFF periods of the compressor during the refrigeration operation, for determining the refrigeration period.
  • the controller preferably starts a defrost at a fixed evaporator temperature thus ensuring that the defrost operation is always timed between two fixed temperatures.
  • the fixed evaporator temperature at which the defrost may be started by switching on the heater can vary according to the type of appliance.
  • the fixed evaporator temperature at which a defrost is started is preferably programmed into the memory of the micro controller at the time of manufacture, for example by the use of an EEPROM or other non volatile programmable memory.
  • this problem can also be solved using for instance a preset target defrost duration.
  • the heater can take the form of a resistive heating element or can be the interior light within the food compartment. This will cause the evaporator temperature to rise to the desired preset defrost temperature at which point the defrost is terminated and normal temperature regulation is resumed.
  • Fig. 2a shows a first embodiment of a controller for controlling a defrost operation in a refrigerator in accordance with the present invention.
  • Reference numeral 1 in Fig. 2 denotes the controller.
  • Reference numeral 2 denotes an evaporator connected via pipe means 3a and 3b to a compressor 3 for circulating cooling fluid through the evaporator 2 to achieve a cooling effect.
  • Reference numeral 22 denotes a temperature sensor mounted in thermal contact with the evaporator 2.
  • Reference numeral 4 denotes a refrigeration controller for performing normal temperature regulation inside a food compartment of the refrigerator. The refrigeration controller 4 receives an input from evaporator temperature sensor 22 and controls the operation of compressor 3.
  • This refrigeration controller can be any kind of temperature controller, for instance a wellknown 2-point controller which keeps the evaporator temperature during a refrigeration period between a low temperature threshold and a high temperature threshold.
  • Reference numeral 5 denotes a user-adjustable temperature dial for setting a desired temperature in the food compartment.
  • Reference numeral 6 denotes a timer means for inhibiting normal temperature regulation of the refrigeration controller 4 after expiry of a refrigeration period time limit.
  • the timer means 6 has a trigger input for triggering the timer. It furthermore has an input for setting a value for the refrigeration period time limit. After the timer has been triggered through its trigger input, it will output an inhibit signal to the refrigeration controller 4 after expiry of the set refrigeration period time limit.
  • the timer 6 counts the compressor running time and does not count time when the compressor is off. To this end the timer 6 receives from the refrigeration controller an indication on the operating state of the compressor.
  • Reference numeral 7 denotes a unit for measuring a defrost duration.
  • Unit 7 receives an input from evaporator temperature sensor 22. It furthermore receives a preset defrost temperature value. It also receives an input from timer 6 indicating when a refrigeration period time limit has been reached and a defrost operation starts.
  • Unit 7 for measuring a defrost duration begins a time measurement whenever this indication has been received from timer 6.
  • Unit 7 terminates the measurement of the defrost time interval when the temperature measured by sensor 22 at the evaporator has reached the preset defrost temperature.
  • Unit 7 outputs the actual defrost duration thus determined to a comparator 8a.
  • Comparator 8a compares the actual defrost duration measured by unit 7 with a target defrost duration value and outputs a difference between the actual defrost duration and the target defrost duration to a unit 8b which calculates a new refrigeration period time limit based on the deviation of the actual defrost duration from the target defrost duration value.
  • the calculated time limit in turn is input into timer 6 for setting the next refrigeration period time limit.
  • Reference numeral 13 denotes an electric heater arranged to supply heat to the evaporator when the same is defrosted.
  • Heater 13 can be in thermal contact with the evaporator or can be arranged elsewhere within the food compartment.
  • Heater 13 can be a resistive or inductive heating element or can be a light bulb for illuminating the food compartment.
  • the heater 13 is switched on to receive electric power from the mains whenever timer 6 outputs an inhibit signal to refrigeration controller 4 to perform a defrost operation.
  • Reference numeral 19 denotes means for detecting a voltage level of the mains supplying the refrigerator with power.
  • the mains voltage level detected by unit 19 is input into a unit 10 for determining a target defrost duration value on the basis of the detected mains voltage.
  • the target defrost duration thus determined is input into comparator 8a.
  • the mains voltage detector 19 is a simple detector circuit consisting of a rectifier diode, a smoothing capacitor connected to that diode and a resistive voltage divider network for lowering the voltage across the capacitor down to a level that can be handled by an Analog to Digital converter circuit.
  • Unit 10 for determining a target defrost duration receives the detected mains voltage level and converts it into a digital value. This digital mains voltage level value is then used by unit 10 to look up a table storing target defrost duration values for a variety of different mains voltage level values.
  • the target defrost duration value looked up in the table of unit 10 is either input into comparator 8a for digitally determining a deviation between the actual defrost duration and the target defrost duration value, or unit 10 converts a value read from its look up table into an analogue value for further processing in comparator 8a.
  • the controller 1 of this embodiment is implemented in digital technology by means of programming the functions of the timer 6, the unit 7 for measuring the defrost duration, the comparator 8a, the unit 8b for calculating a new refrigeration time limit and the unit 10 into a micro controller.
  • the micro controller preferably has A/D conversion means on the chip for processing the analogue signals provided by temperature sensor 22 and the mains voltage level detector 19.
  • the micro controller furthermore implements the control functions of refrigeration controller 4.
  • unit 10 stores a table with different target defrost duration values associated with different mains voltage levels and preferably, moreover with different thermal dispersion values.
  • the determination of the target defrost duration in accordance with the detected power supply condition and possibly other parameters like detected thermal dispersion can be implemented in a variety of different ways.
  • the target defrost duration can be determined depending on these parameters without actually changing a target defrost duration value if the measured value indicating the duration of the defrost time interval is modified in accordance with these parameters before judging on the basis of the modified defrost time interval duration value whether an adjustment of the refrigeration period time limit is necessary.
  • the existence of an explicit target defrost duration value and an explicit comparison of the defrost time interval duration with the target defrost duration is by no means mandatory for implementing a controller in accordance with the principles of the present invention.
  • Fig. 2b shows a modification of the embodiment of Fig. 2a.
  • reference numeral 14 denotes a unit that receives from unit 7 a value indicative of the measured defrost time interval duration.
  • Unit 14 furthermore receives from detector 19 a value indicative of the power supply condition of the refrigerator, e.g. the mains voltage level.
  • Unit 14 modifies the received defrost time interval duration value in accordance with the received power supply condition value and outputs the modified duration value to unit 8b that calculates the next refrigeration period time limit based on the modified duration value received from unit 14.
  • Unit 8b can be implemented in the form of a table that associates refrigeration period time limits to a variety of received duration values. Instead of using tables unit 8b can of course evaluate an analytical function that relates refrigeration period time limits to modified defrost duration values received from unit 14.
  • the entity t real denotes the measured defrost duration.
  • the entity t rated is a modified defrost duration value that takes into account the variation of the thermal energy supplied by the heater during the defrost time interval as a function of a ratio between the rated mains voltage and the real mains voltage detected by unit 19.
  • t cor denotes a corrected defrost time interval duration value.
  • the value t cor is output to unit 8b for calculating the next refrigeration period time limit.
  • the mains voltage U real can be obtained for instance by means of sampling and preferably averaging the samples obtained during the defrost period.
  • Fig. 3 shows a second embodiment of a controller for controlling a defrost operation of a refrigerator in accordance with the present invention.
  • the embodiment of Fig. 3 differs from the embodiment of Fig. 2a in the provision of an ambient temperature detection means 9.
  • the ambient temperature detection means 9 receives a signal from temperature sensor 22 on the evaporator 2. It furthermore receives a signal from refrigeration controller 4 indicating the operating state of the compressor, that is whether the compressor is currently in the ON state or in the OFF state.
  • the embodiment of Fig. 3 is advantageous in that the ambient temperature detection means 9 does not require a separate temperature sensor for sensing the ambient temperature. Rather, the ambient temperature detection means 9 estimates thermal dispersion of the refrigerator based on the temperature curve of the evaporator temperature 22. Preferably, the ambient temperature detection means 9 calculates a rate of rise of evaporator temperature when the compressor is off.
  • rates of rise or fall can be measured either over a constant time period or over a constant temperature change.
  • a simple way to determine the rate of change over a constant temperature is to measure the time toff that the compressor is off and the time t on that the compressor is on, during normal temperature regulation of the refrigeration controller 4, that is in the course of a refrigeration period.
  • the ratio t on /t off is essentially equivalent to the ratio of the rate of rise of evaporator temperature when the compressor is off to the rate of fall of evaporator temperature when the compressor is on, as long as the low temperature threshold and the high temperature threshold used by the refrigeration controller 4 controlling the compressor 3, remain unchanged.
  • the ambient temperature detection means 9 is adapted to evaluate the thermal dispersion of the refrigerator from the ratio of t on /t off , then the ambient temperature detection means 9 need not receive a signal from temperature sensor 22.
  • the thermal dispersion ratio is preferably calculated by unit 9 on a continuous basis in the course of every refrigeration period. Each time the compressor changes its operating state from ON to OFF or from OFF to ON, unit 9 provides a new value for the thermal dispersion ratio to unit 10.
  • unit 10 has a look up storing target defrost duration values for a variety of different mains voltage level values and for a variety of different thermal dispersion values.
  • target defrost duration values for a variety of different mains voltage level values and for a variety of different thermal dispersion values.
  • the thermal dispersion detection means 9 In order to avoid an adverse influence of disturbing factors like frequent or long door openings or the introduction of extremely or cold goods into the food compartment onto the evaluation of the thermal dispersion it is advantageous to provide the thermal dispersion detection means 9 with means for detecting whether said calculated thermal dispersion ratio is stable or not.
  • unit 9 can be provided with memory locations for storing a predetermined number of preceding thermal dispersion ratios, and with means for investigating whether the stored thermal dispersion ratios differ from each other by more than a predetermined threshold variance. Each time a new thermal dispersion ratio is calculated by unit 9, the oldest thermal dispersion ratio in said memory locations is replaced by the newest. If the differences between the stored thermal dispersion ratios is smaller than said predetermined variance threshold, the detected thermal dispersion ratio will then be used by unit 10 for calculating an updated target defrost duration value on the basis of the detected ambient conditions.
  • unit 10 will maintain unchanged the target defrost duration value output to unit 8a unchanged until the conditions for detecting a thermal dispersion ratio have been stabilized, that is, until all thermal dispersion ratios stored in unit 9 differ from each other by no more than said predetermined variance threshold.
  • Unit 8b for determining an updated refrigeration period time limit based on a deviation of the actual defrost duration from the target defrost duration given by unit 10 can be provided to increase the refrigeration period time limit each time the actual defrost duration is smaller than the target defrost duration, and to decrease the refrigeration period time limit each time the actual defrost duration has been found to be larger than the target defrost duration.
  • unit 8b may contain a look up table storing a plurality of refrigeration period time limits in association with respective defrost duration deviation values.
  • Unit 7 for measuring the actual defrost duration comprises a time counter the operation of which is started when receiving an end of refrigeration period signal from timer 6.
  • the time counter stops counting when a comparator for comparing the actual evaporator temperature from temperature sensor 22 with a preset defrost temperature value indicates that the evaporator temperature 22 has reached the preset defrost temperature.
  • unit 7 outputs the end of defrost signal to trigger timer 6 for starting a new refrigeration period.
  • Unit 7 then furthermore outputs the actual defrost duration value to comparator 8a.
  • Fig. 3 can be modified in a way similar to the modifications shown and described in Fig. 2b.
  • modification unit 14 modifies the measured defrost duration in accordance with the detected mains voltage level and in accordance with the detected thermal dispersion of the refrigerator.
  • Fig. 4a shows a third embodiment of a controller according to the present invention. This embodiment differs from the embodiment shown in Fig. 2a in the provision of a unit 11 for updating the refrigeration period time limit set in timer 6. Unit 11 for updating the time limit of timer 6 receives an input from a door position sensor 12. All remaining elements of Fig. 4a are identical with the corresponding elements of Fig. 2a and are denoted with the same reference numerals, such that their description need not be repeated.
  • Fig. 4a addresses the problem that the refrigeration period time limit calculated in unit 8b and set in timer 6 has been determined on the basis of the duration of the preceding defrost operation. If in the course of the refrigeration period there are frequent or long lasting door openings, the time limit for the refrigeration period calculated by unit 8b is no longer up to date.
  • Unit 11 for updating the refrigeration period time limit counts the total time for which the door of the food compartment of the refrigerator is open during the refrigeration period. The total time count is received by timer 6, and the timer 6 subtracts the current total time count from the current period of time left until the refrigeration period time limit is reached. As soon as the updated refrigeration period time limit has been reached, the defrost period starts and the timer means 6 outputs a signal to unit 11 to reset the open door time counter.
  • the controller according to this embodiment is able to reduce the refrigeration period based on an estimation of additional ice accumulation due to door openings without waiting for the next measurement of a defrost duration. A controller according to this embodiment can, therefore, quickly cope with changes in the actual icing conditions of the evaporator and keep the defrost operation of the refrigerator energy-efficient.
  • unit 11 can be provided to count the number of door openings during the refrigeration period. This alternative is, however, inferior to counting the total door open time period in that it will not be able to appropriately react to the situation that the door of the food compartment is opened and left open.
  • Fig. 4a While the embodiment of Fig. 4a includes a unit 10 for calculating a target defrost duration and a unit 19 for detecting a mains voltage level of the refrigerator, the units 9 and 10 are not essential for solving the problem to enable a controller for controlling a defrost operation of a refrigerator to quickly react to changes of the icing conditions of the evaporator due to frequent or long lasting door openings.
  • Fig. 4b is a time chart illustrating the behavior of the evaporator temperature and the sequence of refrigeration periods and defrost periods according to the third embodiment shown in Fig. 4a.
  • the time chart of Fig. 4b shows a refrigeration period n and the evaporator temperature T in the course of that refrigeration period n. No door openings take place during that period n.
  • an n th defrost operation takes place.
  • the measured duration of the n th defrost period influences the duration of the subsequent refrigeration period (n+1).
  • door openings take place, as indicated in the bottom part of Fig. 4b.
  • Updating the refrigeration period time limit on the basis of door openings furthermore has the effect that also the (n+1) st defrost duration is not significantly different from the n th defrost duration since the increased accumulation of ice on the evaporator due to the door of the refrigerator having been open is compensated by means of advancing the next defrost operation, such that both in refrigeration period n and in refrigeration period n+1 the peak amount of ice accumulated on the evaporator is substantially the same.
  • Fig. 4a can be modified in a variety of different ways.
  • the modifications described in connection with Fig. 2b are of course applicable also to the embodiment of Fig. 4a.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Defrosting Systems (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)

Claims (22)

  1. Dispositif de commande (1) pour commander une opération de dégivrage dans un réfrigérateur ayant au moins un compartiment pour aliments, au moins un évaporateur (2) pour refroidir ledit compartiment pour aliments, un moyen de chauffage électrique pour apporter de la chaleur pour dégivrer ledit évaporateur, et un compresseur (3) pour faire circuler du fluide de refroidissement dans ledit évaporateur, le dispositif de commande (1) comprenant :
    - un moyen (4) pour commander une opération de réfrigération dudit compresseur (3) ;
    - un moyen de temporisation (6) pour dégivrer ledit évaporateur après expiration d'une limite de durée de réfrigération ;
    - un moyen (7) pour mesurer une durée d'un intervalle de dégivrage se terminant avec ledit évaporateur (2) ayant atteint une température de dégivrage prédéfinie ;
    - un moyen (8a, 8b) pour comparer ladite durée de l'intervalle de dégivrage avec une durée de dégivrage cible et fixer ladite limite de durée de réfrigération conformément à un écart dudit intervalle de dégivrage par rapport à ladite durée de dégivrage cible ;
    caractérisé par
    - un moyen (19) pour détecter une condition d'alimentation électrique pour ledit moyen de chauffage ; et
    - un moyen (10, 14) pour déterminer ladite durée de dégivrage cible conformément à ladite condition d'alimentation électrique détectée.
  2. Dispositif de commande selon la revendication 1, caractérisé en ce que ledit moyen pour détecter une condition d'alimentation électrique dudit moyen de chauffage est approprié pour détecter une tension de l'alimentation à laquelle le réfrigérateur est connecté, ou pour détecter un courant d'alimentation à travers ledit moyen de chauffage.
  3. Dispositif de commande selon la revendication 1 ou 2, caractérisé par un moyen pour alimenter ledit moyen de chauffage lors du dégivrage dudit évaporateur.
  4. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé par
    - un moyen (9) pour détecter une dispersion thermique dudit réfrigérateur.
  5. Dispositif de commande selon la revendication 4,
    caractérisé en ce que
    - ledit moyen (9) pour détecter une dispersion thermique comprend un capteur de température pour détecter une température ambiante et/ou est approprié pour estimer une température ambiante du réfrigérateur sur la base d'une vitesse d'augmentation de la température de l'évaporateur lorsque le compresseur (3) est hors service et/ou sur la base d'une vitesse de diminution de la température de l'évaporateur lorsque le compresseur (3) est en service.
  6. Dispositif de commande selon la revendication 5,
    caractérisé en ce que
    - ledit moyen (9) pour détecter une dispersion thermique est approprié pour estimer la température ambiante dudit réfrigérateur sur la base d'un rapport de dispersion thermique entre ladite vitesse d'augmentation de la température de l'évaporateur lorsque ledit compresseur (3) est hors service et ladite vitesse de diminution de la température de l'évaporateur lorsque ledit compresseur (3) est en service.
  7. Dispositif de commande selon la revendication 6,
    caractérisé en ce que
    - ledit moyen (9) pour détecter une dispersion thermique est approprié pour mesurer une durée hors service et une durée en service du compresseur (3) pendant ladite période de réfrigération et pour évaluer ledit rapport de dispersion thermique sur la base d'un rapport entre ladite durée en service du compresseur (3) et ladite durée hors service du compresseur (3) ou sur la base d'un rapport entre ladite durée en service du compresseur (3) et une somme de ladite durée en service du compresseur et de ladite durée hors service du compresseur.
  8. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    - ledit moyen (10) pour déterminer une durée de dégivrage cible comprend un moyen de mémoire pour stocker une table de conversion qui comprend une pluralité de conditions d'alimentation électrique et de valeurs de durée de dégivrage cible associées.
  9. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    - ledit moyen (8a, 8b) pour comparer ledit intervalle de dégivrage avec une durée de dégivrage cible et pour fixer ladite limite de durée de réfrigération conformément à un écart dudit intervalle de dégivrage par rapport à ladite durée de dégivrage cible inclut un moyen de mémoire pour stocker une table de conversion qui comprend une pluralité de valeurs de durée de dégivrage cible, de valeurs d'intervalle de dégivrage et de valeurs de limite de durée de réfrigération associées.
  10. Dispositif de commande selon l'une quelconque des revendications 1 à 8,
    caractérisé en ce que
    - ledit moyen (8a, 8b) pour comparer ledit intervalle de dégivrage avec une durée de dégivrage ciblé et pour fixer ladite limite de durée de réfrigération conformément à un écart dudit intervalle de dégivrage par rapport à ladite durée de dégivrage cible est approprié pour incrémenter ladite limite de durée de réfrigération si ledit intervalle de dégivrage est plus petit que ladite durée de dégivrage cible, et pour décrémenter ladite limite de durée de réfrigération si ledit intervalle de dégivrage est plus grand que ladite durée de dégivrage cible.
  11. Dispositif de commande selon l'une quelconque des revendications 1 à 7,
    caractérisé en ce que
    - ledit moyen pour déterminer la durée de dégivrage cible comprend un moyen (14) pour modifier une valeur indiquant la durée de l'intervalle de dégivrage mesurée conformément à ladite condition d'alimentation électrique détectée par ledit moyen de détection (19) ; et
    - ledit moyen (8b) pour comparer ledit intervalle de dégivrage avec une durée de dégivrage cible est approprié pour fixer ladite limite de durée de réfrigération conformément à ladite valeur modifiée indiquant la durée de l'intervalle de dégivrage mesurée reçue dudit moyen modifié (14).
  12. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé par
    - un moyen (12) pour détecter si une porte dudit compartiment pour aliments est ouverte, et pour accumuler une durée d'ouverture de porte pendant chaque période de réfrigération ; et
    - un moyen (11) pour réduire ladite limite de durée de réfrigération conformément à ladite durée d'ouverture de porte accumulée.
  13. Dispositif de commande selon la revendication 12,
    caractérisé en ce que
    - ledit moyen (11) pour réduire ladite limite de durée de réfrigération est approprié pour réduire ladite limite de durée de réfrigération en proportion de ladite durée d'ouverture de porte accumulée ou en proportion d'un nombre compté d'ouvertures de porte.
  14. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    - ledit moyen (7) pour mesurer l'intervalle de dégivrage est approprié pour commencer de mesurer ledit intervalle de dégivrage à l'expiration de ladite limite de durée de réfrigération.
  15. Dispositif de commande selon l'une quelconque des revendications 1 à 13,
    caractérisé en ce que
    - ledit moyen de temporisation (6) pour inhiber une opération dudit compresseur (3) après l'expiration d'une limite de durée de réfrigération et dégivrer ledit évaporateur est approprié pour recevoir un signal indiquant une température réelle dudit évaporateur (2) ; et
    - pour inhiber l'opération dudit compresseur (3) et commencer le dégivrage dudit évaporateur (2) lorsque ladite limite de durée de réfrigération est parvenue à expiration et lorsque ladite température de l'évaporateur a atteint une valeur inférieure à une température de début de dégivrage prédéterminée ;
    - ledit moyen (7) pour mesurer l'intervalle de dégivrage étant approprié pour commencer de mesurer ledit intervalle de dégivrage lorsque ladite température de l'évaporateur a atteint ladite température de début de dégivrage.
  16. Dispositif de commande selon la revendication 15,
    caractérisé en ce que
    - ledit moyen de temporisation (6) est approprié pour initier une phase additionnelle de service du compresseur lorsque ledit intervalle de réfrigération vient à expiration et que ladite température de l'évaporateur est supérieure à ladite température de début de dégivrage prédéterminée, et pour mettre fin à ladite phase additionnelle de service du compresseur lorsque ledit évaporateur (2) a atteint ladite température de début de dégivrage.
  17. Dispositif de commande selon la revendication 15 ou 16,
    caractérisé en ce que
    - ledit moyen (4) pour commander une opération de réfrigération est approprié pour activer ledit compresseur (3) lorsque la température de l'évaporateur a atteint un seuil supérieur de température, et pour couper ledit compresseur (3) lorsque la température de l'évaporateur a atteint un seuil inférieur de température ;
    - ladite température de début de dégivrage étant ledit seuil inférieur de température.
  18. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé par
    - ledit moyen pour alimenter ledit moyen de chauffage est approprié pour alimenter ledit moyen de chauffage lorsque ladite limite de durée de réfrigération est parvenue à expiration et que ladite température de l'évaporateur a atteint une valeur inférieure à ladite température de début de dégivrage prédéterminée, et pour couper l'alimentation dudit moyen de chauffage lorsque ladite température de l'évaporateur a atteint ladite température de dégivrage prédéterminée.
  19. Dispositif de commande selon l'une quelconque des revendications 2 à 18,
    caractérisé par
    - ledit moyen pour alimenter ledit moyen de chauffage étant connecté pour alimenter une porte opérée pour ledit compartiment pour aliments.
  20. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    - ledit moyen de temporisation (6) est approprié pour mesurer ladite période de réfrigération au moyen de l'accumulation du temps de fonctionnement du compresseur uniquement, ou au moyen d'une mesure du temps réel.
  21. Dispositif de commande selon l'une quelconque des revendications précédentes,
    caractérisé en ce que
    - ledit moyen (4) pour commander une opération de réfrigération dudit compresseur (3) est approprié pour commander conformément à une valeur (5) de température cible du compartiment pour aliments réglable par l'utilisateur.
  22. Procédé pour commander une opération de dégivrage dans un réfrigérateur ayant un compartiment pour aliments, un évaporateur (2) pour refroidir ledit compartiment pour aliments, un moyen de chauffage électrique pour fournir de la chaleur pour dégivrer ledit évaporateur, et un compresseur (3) pour faire circuler du fluide de refroidissement dans ledit évaporateur, le procédé comprenant les étapes de
    - commander une opération de réfrigération dudit compresseur (3),
    - dégivrer ledit évaporateur (2) après expiration d'une limite de durée de réfrigération en alimentant ledit moyen de chauffage, et
    - mesurer un intervalle de dégivrage se terminant avec ledit évaporateur (2) ayant atteint une température de dégivrage prédéterminée ;
    - comparer ledit intervalle de dégivrage avec une durée de dégivrage cible et fixer ladite limite de durée de réfrigération conformément à un écart dudit intervalle de dégivrage par rapport à ladite durée de dégivrage cible ;
    caractérisé par
    - détecter une condition d'alimentation électrique pour ledit moyen de chauffage ; et
    - déterminer ladite durée de dégivrage cible conformément à ladite condition d'alimentation électrique détectée.
EP20000117310 2000-08-18 2000-08-18 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur Expired - Lifetime EP1180652B1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP20000117310 EP1180652B1 (fr) 2000-08-18 2000-08-18 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur
DE2000630971 DE60030971T2 (de) 2000-08-18 2000-08-18 Steuervorrichtung und Verfahren zum Steuern des Abtauvorgangs in einem Kühlschrank
TR2001/02371A TR200102371A2 (tr) 2000-08-18 2001-08-16 Bir buzdolabìnda eritme içleminin kontrol edilmesi i‡in kontrol cihazì ve y”ntem.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20000117310 EP1180652B1 (fr) 2000-08-18 2000-08-18 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur

Publications (2)

Publication Number Publication Date
EP1180652A1 EP1180652A1 (fr) 2002-02-20
EP1180652B1 true EP1180652B1 (fr) 2006-09-27

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EP20000117310 Expired - Lifetime EP1180652B1 (fr) 2000-08-18 2000-08-18 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur

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Country Link
EP (1) EP1180652B1 (fr)
DE (1) DE60030971T2 (fr)
TR (1) TR200102371A2 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10221904A1 (de) * 2002-05-16 2003-12-04 Bsh Bosch Siemens Hausgeraete Gefriergerät mit Abtaufunktion und Betriebsverfahren dafür
DE10315522A1 (de) * 2003-04-04 2004-10-14 BSH Bosch und Siemens Hausgeräte GmbH Verfahren zur Leistungsregelung einer Abtauheizung und Kältegerät mit integrierter Abtauheizung
US6964172B2 (en) 2004-02-24 2005-11-15 Carrier Corporation Adaptive defrost method
DE102008054935A1 (de) * 2008-12-18 2010-06-24 BSH Bosch und Siemens Hausgeräte GmbH Kältegerät mit einer Abtauheizung
EP2811244A3 (fr) 2013-06-07 2015-04-22 Indesit Company Beyaz Esya San.Ve Tic A.S. Cartouche d'absorbeur d'humidité utilisée dans les conduites d'air de réfrigérateurs
CN115183514A (zh) * 2022-06-14 2022-10-14 海信（山东）冰箱有限公司 冰箱及压缩机转速控制方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4251988A (en) 1978-12-08 1981-02-24 Amf Incorporated Defrosting system using actual defrosting time as a controlling parameter
US4327557A (en) * 1980-05-30 1982-05-04 Whirlpool Corporation Adaptive defrost control system
US4528821A (en) * 1982-07-28 1985-07-16 Whirlpool Corporation Adaptive demand defrost control for a refrigerator
DE3235642A1 (de) * 1982-09-25 1984-03-29 3 E Elektronik-Elektro-Energieanlagen Baugesellschaft mbH, 5500 Trier Einrichtung zur elektrischen abtauregelung fuer den verdampfer einer kaelteanlage
US4689965A (en) * 1985-12-27 1987-09-01 Whirlpool Corporation Adaptive defrost control for a refrigerator
GB8702722D0 (en) * 1987-02-06 1987-03-11 York Int Ltd Defrosting of heat exchangers
KR0159506B1 (ko) * 1990-08-16 1999-01-15 강진구 냉장고의 제상타이머 장치
US5363669A (en) * 1992-11-18 1994-11-15 Whirlpool Corporation Defrost cycle controller
US5415005A (en) * 1993-12-09 1995-05-16 Long Island Lighting Company Defrost control device and method
US5440893A (en) * 1994-02-28 1995-08-15 Maytag Corporation Adaptive defrost control system
DE4418874A1 (de) * 1994-05-30 1996-03-21 Bosch Siemens Hausgeraete Steuereinrichtung zum Betrieb eines Kühl- oder Gefriergerätes
EP1030137B1 (fr) * 1999-02-19 2005-02-02 Ranco Incorporated of Delaware Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur

Also Published As

Publication number Publication date
EP1180652A1 (fr) 2002-02-20
TR200102371A3 (tr) 2002-03-21
DE60030971T2 (de) 2007-06-14
DE60030971D1 (de) 2006-11-09
TR200102371A2 (tr) 2002-03-21

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