EP1030137B1 - 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
EP1030137B1
EP1030137B1 EP19990102741 EP99102741A EP1030137B1 EP 1030137 B1 EP1030137 B1 EP 1030137B1 EP 19990102741 EP19990102741 EP 19990102741 EP 99102741 A EP99102741 A EP 99102741A EP 1030137 B1 EP1030137 B1 EP 1030137B1
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EP
European Patent Office
Prior art keywords
defrost
temperature
evaporator
compressor
refrigeration
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
EP19990102741
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German (de)
English (en)
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EP1030137A1 (fr
Inventor
Graham Bailey
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
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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.)
Filing date
Publication date
Application filed by Ranco Inc of Delaware, Ranco Inc filed Critical Ranco Inc of Delaware
Priority to DE1999623531 priority Critical patent/DE69923531T2/de
Priority to ES99102741T priority patent/ES2236975T3/es
Priority to EP19990102741 priority patent/EP1030137B1/fr
Priority to AU34242/00A priority patent/AU3424200A/en
Priority to PCT/EP2000/001364 priority patent/WO2000049350A1/fr
Priority to EP00912486A priority patent/EP1157245A1/fr
Publication of EP1030137A1 publication Critical patent/EP1030137A1/fr
Application granted granted Critical
Publication of EP1030137B1 publication Critical patent/EP1030137B1/fr
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Expired - Lifetime legal-status Critical Current

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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
    • F25B2500/00—Problems to be solved
    • F25B2500/29—High ambient temperatures
    • 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
    • F25B2500/00—Problems to be solved
    • F25B2500/31—Low ambient temperatures
    • 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 21.
  • a controller and a method of this kind are known from DE 29 45 691.
  • 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.
  • 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, particularly if no additional source of energy 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 thermal dispersion through the refrigerator appliance insulation.
  • Fig. 1a shows a typical behavior of the evaporator temperature T over time in a first condition A when the ambient temperature is low, and in a second condition B when the ambient temperature is high. From Fig.
  • the controller detects a shorter defrost time interval t 2 than the target defrost duration and, therefore, decreases the frequency of defrost operations, that is increases the refrigeration period between consecutive defrost operations.
  • the known controller is furthermore adapted to initiate a defrost immediately after the calculated refrigeration period time limit has expired.
  • This has the disadvantage that the duration of the defrost time interval until the evaporator has reached the preset defrost temperature, depends on the temperature of the evaporator at the end of the refrigeration period.
  • 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. This results in an increased energy consumption of the refrigerator.
  • the thermal dispersion of the refrigerator is detected, and the target defrost duration is adjusted in accordance with the detected thermal dispersion.
  • the thermal dispersion of the refrigerator depends on the ambient temperature of the refrigerator. Therefore, it is convenient to detect the thermal dispersion by means of detecting the ambient temperature of the refrigerator.
  • the ambient temperature of the refrigerator can be detected by means of an ambient temperature sensor or by means of estimating the ambient temperature on the basis of the rate of rise of evaporator temperature when the compressor is off, or on the basis of a rate of fall of evaporator temperature when the compressor is on, or preferably, on the basis of a ratio of these rates.
  • 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 ambient conditions of the refrigerator.
  • the present invention therefore improves the energy efficiency of a refrigerator with an adaptive defrost function and enables an adaptive defrost not requiring a heater at the evaporator for accelerating the defrost operation.
  • the optimum target defrost time can be determined during development testing of the refrigerator appliance 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 various 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. Also, fuzzy logic can be used. Alternatively, the target defrost duration can be calculated through a mathematical formula as a function of the detected thermal dispersion. For example, a nominal target defrost duration of 30 minutes at 25°C can be adjusted by a factor proportional to the temperature deviation from the 25°C. For calculating target defrost durations 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 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 microcontroller at the time of manufacture, for example by the use of an EEPROM or other non volatile programmable memory.
  • a compartment heater can be switched on.
  • the compartment 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. 2 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 ends 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 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.
  • the calculated time limit in turn is input into timer 6 for setting the next refrigeration period time limit.
  • Reference numeral 9 denotes a means for detecting an ambient temperature of the refrigerator.
  • the ambient temperature detected by unit 9 is input into a unit 10 for determining a target defrost duration on the basis of the detected ambient temperature.
  • the target defrost duration thus determined is input into comparator 8a.
  • the ambient temperature detector 9 is a temperature sensor mounted at the refrigerator in a location suitable for measuring the ambient temperature.
  • Unit 10 for determining a target defrost duration receives the detected ambient temperature and converts the detected temperature into a digital value. This digital temperature value is then used by unit 10 to look up a table storing target defrost duration values for a variety of different ambient temperature values.
  • the target defrost duration 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, 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 microcontroller.
  • the microcontroller preferably has A/D conversion means on the chip, for processing the analogue signals provided by temperature sensor 22 and the temperature sensor 9 for detecting the ambient temperature.
  • the microcontroller furthermore implements the control functions of refrigeration controller 4.
  • 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. 2 in the 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 disposion ratio is preferably calculated by unit 9 on a continuous basis in the course of every refrigeration period.
  • unit 9 provides a new value for the thermal dispersion ratio to unit 10.
  • 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.
  • unit 10 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 on the basis of the detected ambient conditions. Otherwise, unit 10 will maintain the target defrost duration 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. 4a shows a third embodiment of a controller according to the present invention. This embodiment differs from the embodiment shown in Fig. 2 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. 2 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 9 for detecting an ambient temperature of the refrigerator, the units 9 and 10 are not mandatory for solving the problem, to enable to 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. 5 shows a fourth embodiment of a controller for controlling a defrost operation according to the present invention.
  • the embodiment of Fig. 5 differs from the embodiment of Fig. 2 in the provision of a time-out unit 13 in the path of the inhibit signal output by timer 6.
  • This embodiment addresses the problem that if the refrigerator appliance is operated in an ambient temperature lower than the preset defrost temperature, the defrost operation will not terminate because the evaporator 2 will possibly not reach the preset defrost temperature which is used by unit 7 for measuring the defrost duration.
  • unit 7 Under the condition that the ambient temperature of the refrigerator is lower than the preset defrost temperature, unit 7 will thus not indicate an end of the defrost period and timer 6 will not be retriggered to start a new refrigeration period.
  • the embodiment of Fig. 5 outputs the inhibit signal of timer 6 to time-out unit 13.
  • the time-out unit 13 passes the inhibit signal onto the refrigeration controller 4 as long as a preset time-out interval for unit 13 beginning with the arrival of the inhibit signal has not been exceeded.
  • timer 6 If the inhibit signal output by timer 6 prevails for more than the preset time-out interval in unit 13, this unit will no longer pass on the inhibit signal to the refrigeration controller 4 such that the refrigeration controller 4 can then resume normal temperature control operation. As soon as timer 6 is retriggered by unit 7, timer 6 switches off the inhibit signal and time-out unit 13 is reset such that a normal operation of the controller for controlling the defrost can be resumed.
  • Fig. 5 While the embodiment of Fig. 5 has been described including the units 9 and 10 for detecting an ambient temperature of the refrigerator and for calculating a target defrost duration on the basis of the thermal dispersion of the refrigerator, these units are not mandatory for solving the problem addressed by the embodiment of Fig. 5. For solving this problem it is, therefore, possible to replace in Fig. 5 the unit 9 for detecting an ambient temperature and the unit 10 for determining a target defrost duration by a means for providing a preset target defrost duration.

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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)

Claims (22)

  1. Unité de commande (1) pour destiné à la commande d'une opération de dégivrage dans un réfrigérateur, comprenant au moins un compartiment à denrées fraíches, au moins un évaporateur (2) pour refroidir ledit compartiment à denrées fraíches, et un compresseur (3) pour circuler un fluide de refroidissement à travers ledit évaporateur, l'unité de commande (1) comprenant :
    un moyen (4) pour commander une opération de réfrigération dudit compresseur (3) ;
    un moyen minuteur (6) pour dégivrer ledit évaporateur, après l'expiration d'une limite de temps de la période de réfrigération ;
    un moyen (7) pour mesurer une durée d'un intervalle de temps de dégivrage, qui se termine lorsque ledit évaporateur (2) a atteint une température prédéfinie de dégivrage ;
    un moyen (8a, 8b) pour comparer ladite durée d'un intervalle de temps de dégivrage à une durée cible de dégivrage, et pour fixer ladite limite de temps de la période de réfrigération, en fonction d'un écart entre ledit intervalle de temps de dégivrage et ladite durée cible de dégivrage ;
       caractérisé par :
    un moyen (9) pour détecter une dispersion thermique dudit réfrigérateur ; et
    un moyen (10) pour déterminer ladite durée cible de dégivrage, en fonction de ladite dispersion thermique.
  2. Unité de contrôle selon la revendication 1,
       caractérisée en ce que
    ledit moyen (9), servant à détecter une dispersion thermique, comprend un capteur de température, afin de détecter une température ambiante.
  3. Unité de contrôle selon la revendication 1,
       caractérisée en ce que
    ledit moyen (9), servant à détecter une dispersion thermique, est propre à estimer une température ambiante du réfrigérateur, sur la base d'une vitesse d'élévation de la température de l'évaporateur, lorsque le compresseur (3) est hors fonction, et/ou sur la base d'une vitesse de chute de la température de l'évaporateur, lorsque ledit compresseur (3) est en fonction.
  4. Unité de contrôle selon la revendication 3,
       caractérisée en ce que
    ledit moyen (9), servant à détecter une dispersion thermique, est propre à estimer la température ambiante dudit réfrigérateur, sur la base d'un rapport de dispersion thermique de ladite vitesse d'élévation de la température de l'évaporateur, lorsque ledit compresseur (3) est hors fonction, à ladite vitesse d'élévation de la température de l'évaporateur, lorsque ledit compresseur (3) est en fonction.
  5. Unité de contrôle selon la revendication 4,
       caractérisée en ce que
    ledit moyen (9), servant à détecter une dispersion thermique, est propre à mesurer une période de temps ARRET et une période de temps MARCHE du compresseur (3), pendant ladite période de réfrigération, et à évaluer ledit rapport de dispersion thermique, sur la base d'un rapport de ladite période de temps MARCHE du compresseur à ladite période de temps ARRET du compresseur, ou sur la base d'un rapport de ladite période de temps MARCHE du compresseur à une somme de ladite période de temps MARCHE du compresseur et de ladite période de temps ARRET du compresseur.
  6. Unité de contrôle selon l'une quelconque des revendications précédentes,
       caractérisée en ce que
    ledit moyen (10), servant à déterminer une durée cible de dégivrage, comprend un moyen de mémorisation pour conserver une table à consulter, qui comprend une pluralité de valeurs de températures ambiantes et de valeurs associées de durées cibles de dégivrage.
  7. Unité de contrôle selon l'une quelconque des revendications 1 à 5,
       caractérisée en ce que
    ledit moyen (10), servant à déterminer une durée cible de dégivrage, est propre à calculer une valeur de décalage, qui est fonction d'un écart de ladite température ambiante par rapport à une valeur nominale de température ambiante, et à calculer ladite durée cible de dégivrage en additionnant ladite valeur calculée de décalage à une valeur nominale de durée cible de dégivrage.
  8. Unité de contrôle selon la revendication 7,
       caractérisée en ce que
    ladite fonction est une fonction linéaire ou une fonction quadratique, ou une fonction ayant un terme linéaire et un terme quadratique.
  9. Unité de contrôle selon l'une quelconque des revendications précédentes,
       caractérisée en ce que
    ledit moyen (8a, 8b), servant à comparer ledit intervalle de temps de dégivrage à une durée cible de dégivrage, et à fixer ladite limite de temps de la période de réfrigération, en fonction d'un écart entre ledit intervalle de temps de dégivrage et ladite durée cible de dégivrage, comprend un moyen de mémorisation pour conserver une table à consulter, comprenant une pluralité de valeurs de durées cibles de dégivrage, de valeurs d'intervalles de temps de dégivrage, et de valeurs associées de limites de temps de périodes de réfrigération.
  10. Unité de contrôle selon l'une quelconque des revendications 1 à 8,
       caractérisée en ce que
    ledit moyen (8a, 8b), servant à comparer ledit intervalle de temps de dégivrage à une durée cible de dégivrage, et à fixer ladite limite de temps de la période de réfrigération, en fonction d'un écart entre ledit intervalle de temps de dégivrage et ladite durée cible de dégivrage, est propre à incrémenter ladite limite de temps de la période de réfrigération, si ledit intervalle de temps de dégivrage est inférieur à ladite durée cible de dégivrage, et à décrémenter ladite limite de temps de la période de réfrigération si ledit intervalle de temps de dégivrage est supérieur à ladite durée cible de dégivrage.
  11. Unité de contrôle selon l'une quelconque des revendications précédentes,
       caractérisée par
    un moyen (12) servant à détecter si une porte dudit compartiment à denrées fraíches est ouverte, et à accumuler une période de temps de porte à l'état ouvert, pendant chaque période de réfrigération ; et
    un moyen (11) servant à réduire ladite limite de temps de la période de réfrigération en fonction de ladite période de temps de porte à l'état ouvert, accumulée.
  12. Unité de contrôle selon la revendication 11,
       caractérisée en ce que
    ledit moyen (11), servant à réduire ladite limite de temps de la période de réfrigération, est propre à réduire ladite limite de temps de la période de réfrigération, proportionnellement à ladite période de temps de porte à l'état ouvert, accumulée, ou proportionnellement à un nombre compté d'ouvertures de porte.
  13. Unité de contrôle selon l'une quelconque des revendications précédentes,
       caractérisée en ce que
    ledit moyen de mesure d'intervalle de temps de dégivrage (7) est propre à commencer à mesurer ledit intervalle de temps de dégivrage, à l'expiration de ladite limite de temps de la période de réfrigération.
  14. Unité de contrôle selon l'une quelconque des revendications 1 à 12,
       caractérisée en ce que
    ledit moyen minuteur (6), pour empêcher un fonctionnement dudit compresseur (3), après l'expiration d'une limite de temps de la période de réfrigération, et pour dégivrer ledit évaporateur, est propre à recevoir un signal indiquant une température réelle dudit évaporateur (2), et
    à empêcher le fonctionnement dudit compresseur (3) et démarrer le dégivrage dudit évaporateur (2), lorsque ladite limite de temps de la période de réfrigération est expirée et que la température dudit évaporateur a atteint une valeur inférieure à une température prédéterminée de démarrage de dégivrage ;
    ledit moyen de mesure d'intervalle de temps de dégivrage (7) est propre à commencer à mesurer ledit intervalle de temps de dégivrage, lorsque ladite température de l'évaporateur a atteint ladite température de démarrage de dégivrage.
  15. Unité de contrôle selon la revendication 14,
       caractérisée en ce que
    ledit moyen minuteur (6) est propre à lancer une phase MARCHE supplémentaire du compresseur, lorsque ledit intervalle de temps de période de réfrigération expire et que la température dudit évaporateur est supérieure à ladite température prédéfinie de démarrage de dégivrage, et à mettre fin à ladite phase MARCHE supplémentaire du compresseur, lorsque ledit évaporateur (2) a atteint ladite température de démarrage de dégivrage.
  16. Unité de contrôle selon la revendication 14 ou 15,
       caractérisée en ce que
    ledit moyen (4), servant à commander un fonctionnement de réfrigération, est propre à mettre en fonction ledit compresseur (3) lorsque la température de l'évaporateur a atteint un seuil supérieur de température, et à mettre hors fonction ledit compresseur (3) lorsque la température de l'évaporateur a atteint un seuil inférieur de température ;
    ladite température de démarrage de dégivrage étant ledit seuil inférieur de température.
  17. Unité de contrôle selon l'une quelconque des revendications précédentes,
       caractérisée par
    un moyen (13) servant à permettre le fonctionnement dudit compresseur (3), lorsque ledit intervalle de temps de dégivrage dépasse une limite prédéfinie de temps de la période de dégivrage.
  18. Unité de contrôle selon l'une quelconque des revendications 1 à 16,
       caractérisée par
    un moyen de chauffage dudit évaporateur ; et
    un moyen servant à l'alimentation en énergie dudit moyen de chauffage, lorsque ledit intervalle de temps de dégivrage dépasse une limite prédéfinie de temps de la période de dégivrage, et à la coupure de l'alimentation en énergie dudit moyen de chauffage, lorsque la température de l'évaporateur a atteint ladite température prédéfinie de dégivrage.
  19. Unité de contrôle selon l'une quelconque des revendications 1 à 16,
       caractérisée par
    une ampoule d'éclairage à commande par la porte, pour ledit compartiment de denrées fraíches ; et
    un moyen servant à l'alimentation en énergie de ladite ampoule d'éclairage, lorsque ledit intervalle de temps de dégivrage dépasse une limite prédéfinie de temps de la période de dégivrage, et à la coupure de l'alimentation en énergie de ladite ampoule d'éclairage, lorsque la température de l'évaporateur a atteint ladite température prédéfinie de dégivrage.
  20. Unité de contrôle selon l'une quelconque des revendications précédentes,
       caractérisée en ce que
    ledit moyen minuteur (6) est propre à mesurer ladite période de réfrigération, au moyen de l'accumulation du temps de fonctionnement uniquement du compresseur, ou au moyen de la mesure du temps réel.
  21. Unité de contrôle selon l'une quelconque des revendications précédentes,
       caractérisée en ce que
    ledit moyen (4), servant à la commande d'une opération de réfrigération dudit compresseur (3), est propre à effectuer la commande suivant une valeur cible de température (5), réglable par l'utilisateur pour le compartiment à denrées fraíches.
  22. Procédé de commande d'une opération de dégivrage dans un réfrigérateur, comprenant un compartiment à denrées fraíches, un évaporateur (2) pour le refroidissement dudit compartiment à denrées fraíches, et un compresseur (3) pour faire circuler un fluide de refroidissement à travers ledit évaporateur, le procédé comprenant les étapes de :
    commande d'une opération de réfrigération dudit compresseur (3) ;
    dégivrage dudit évaporateur (2), après l'expiration d'une limite de temps de la période de réfrigération ; et
    mesure d'un intervalle de temps de dégivrage, qui se termine lorsque ledit évaporateur (2) a atteint une température prédéfinie de dégivrage ;
    comparaison dudit intervalle de temps de dégivrage à une durée cible de dégivrage, et fixation de ladite limite de temps de la période de réfrigération, en fonction d'un écart entre ledit intervalle de temps de dégivrage et ladite durée cible de dégivrage ;
       caractérisé par
    la détection d'une température ambiante dudit réfrigérateur ; et
    la détermination de ladite durée cible de dégivrage, en fonction de ladite température ambiante détectée.
EP19990102741 1999-02-19 1999-02-19 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur Expired - Lifetime EP1030137B1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
DE1999623531 DE69923531T2 (de) 1999-02-19 1999-02-19 Steuervorrichtung und Verfahren zum Steuern des Abtauvorganges in einem Kühlschrank
ES99102741T ES2236975T3 (es) 1999-02-19 1999-02-19 Controlador y metodo para controlar la operacion de descongelacion en un refrigerador.
EP19990102741 EP1030137B1 (fr) 1999-02-19 1999-02-19 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur
AU34242/00A AU3424200A (en) 1999-02-19 2000-02-18 Controller and method for controlling a defrost operation in a refrigerator
PCT/EP2000/001364 WO2000049350A1 (fr) 1999-02-19 2000-02-18 Module et procede de commande du processus de degivrage dans un refrigerateur
EP00912486A EP1157245A1 (fr) 1999-02-19 2000-02-18 Module et procede de commande du processus de degivrage dans un refrigerateur

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19990102741 EP1030137B1 (fr) 1999-02-19 1999-02-19 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur

Publications (2)

Publication Number Publication Date
EP1030137A1 EP1030137A1 (fr) 2000-08-23
EP1030137B1 true EP1030137B1 (fr) 2005-02-02

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
EP19990102741 Expired - Lifetime EP1030137B1 (fr) 1999-02-19 1999-02-19 Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur
EP00912486A Withdrawn EP1157245A1 (fr) 1999-02-19 2000-02-18 Module et procede de commande du processus de degivrage dans un refrigerateur

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP00912486A Withdrawn EP1157245A1 (fr) 1999-02-19 2000-02-18 Module et procede de commande du processus de degivrage dans un refrigerateur

Country Status (5)

Country Link
EP (2) EP1030137B1 (fr)
AU (1) AU3424200A (fr)
DE (1) DE69923531T2 (fr)
ES (1) ES2236975T3 (fr)
WO (1) WO2000049350A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1180652B1 (fr) * 2000-08-18 2006-09-27 Ranco Incorporated of Delaware Dispositif de commande et procédé pour commander l'opération de dégivrage dans un réfrigérateur
GB2405360B (en) * 2003-08-27 2007-02-07 Ebac Ltd Dehumidifiers
DE102007034295A1 (de) * 2007-07-24 2009-01-29 BSH Bosch und Siemens Hausgeräte GmbH Kältegerät
CN114111193A (zh) * 2020-08-25 2022-03-01 海信（山东）冰箱有限公司 一种冰箱和确定化霜周期时长的方法

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3681933A (en) * 1970-08-20 1972-08-08 Dynamics Corp America Defrost control
US4251988A (en) 1978-12-08 1981-02-24 Amf Incorporated Defrosting system using actual defrosting time as a controlling parameter
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
US4850204A (en) * 1987-08-26 1989-07-25 Paragon Electric Company, Inc. Adaptive defrost system with ambient condition change detector
US5046324A (en) * 1990-06-20 1991-09-10 Sanyo Electric Co., Ltd. Defrosting controller for refrigeration systems
US5363669A (en) * 1992-11-18 1994-11-15 Whirlpool Corporation Defrost cycle controller
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
IT1266851B1 (it) * 1994-06-08 1997-01-21 Merloni Elettrodomestici Spa Metodo per il controllo di un apparato frigorifero, ed apparato implementante tale metodo.
US5533350A (en) * 1994-12-16 1996-07-09 Robertshaw Controls Company Defrost control of a refrigeration system utilizing ambient air temperature determination

Also Published As

Publication number Publication date
WO2000049350A1 (fr) 2000-08-24
DE69923531T2 (de) 2006-03-30
EP1030137A1 (fr) 2000-08-23
EP1157245A1 (fr) 2001-11-28
ES2236975T3 (es) 2005-07-16
AU3424200A (en) 2000-09-04
DE69923531D1 (de) 2005-03-10

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