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EP-3764033-B1 - REFRIGERATOR AND CONTROLLING METHOD THEREOF

EP3764033B1EP 3764033 B1EP3764033 B1EP 3764033B1EP-3764033-B1

Inventors

  • Choi, Sangbok
  • KIM, SUNGWOOK
  • PARK, KYONGBAE
  • JHEE, SUNG

Dates

Publication Date
20260513
Application Date
20190131

Claims (12)

  1. A method for controlling a refrigerator comprising: allowing a heat generating element (273) of a sensor (270) reacting to a change in a flow rate of air to be turned on for a predetermined period of time and then turned off; detecting (S13) a first detection temperature (Ht1) of the heat generating element (273) by the sensor (270) in a state in which the heat generating element (273) is turned on and detecting (S17) a second detection temperature (Ht2) of the heat generating element (273) by the sensor (270) in a state in which the heat generating element (273) is turned off; detecting (S19) an amount of frost on an evaporator (30) based on a temperature difference between the first detection temperature (Ht1) and the second detection temperature (Ht2), determining (S29) whether a temperature difference value between the first detection temperature (Ht1) and the second detection temperature (Ht2) is less than a first reference difference value; and performing (S30) a defrost operation of removing frost generated on a surface of the evaporator (30) when it is determined that a temperature difference value between the first detection temperature (Ht1) and the second detection temperature (Ht2) is less than a first reference difference value, wherein the heat generating element (273) is turned on while a storage compartment (11) of the refrigerator is being cooled and a blowing fan (70) for cooling a storage compartment (11) is being driven, wherein when an amount of frost on the evaporator (30) increases, the temperature difference value decreases.
  2. The method of claim 1, wherein the first detection temperature (Ht1) is a temperature detected by a sensing element (274) of the sensor (270) immediately after the heat generating element (273) is turned on.
  3. The method of claim 1, wherein the second detection temperature (Ht2) is a temperature detected by a sensing element (274) of the sensor (270) immediately after the heat generating element (273) is turned off.
  4. The method of claim 1, wherein the first detection temperature (Ht1) is a lowest temperature value during a period of time when the heat generating element (273) is turned on.
  5. The method of claim 1, wherein the second detection temperature (Ht2) is a highest temperature value after the heat generating element (273) is turned off.
  6. The method of claim 1, further comprising: determining (S32) whether a temperature difference value between the first detection temperature (Ht1) and the second detection temperature (Ht2) is less than a second reference difference value when the heat generating element (273) is turned on for the predetermined period of time and then turned off, wherein the heat generating element (273) is turned on according to whether a temperature difference value between the first detection temperature (Ht1) and the second detection temperature (Ht2) is less than a second reference difference value, wherein, preferably, the heat generating element (273) is turned on based on an accumulated cooling operation time of the storage compartment (11) when the temperature difference value between the first detection temperature (Ht1) and the second detection temperature (Ht2) is less than the second reference difference value.
  7. The method of claim 1, further comprising: allowing the heat generating element (273) to be turned on based on an accumulated cooling operation time of a storage compartment (11) when the heat generating element (273) is turned on for the predetermined period of time and then turned off.
  8. A refrigerator comprising: an inner case (12) configured to define a storage space (11); a cooling duct (20) configured to guide flow of air in the storage space (11) and define a heat exchange space (222) with the inner case (12); an evaporator (30) disposed in the heat exchange space (222); a bypass passage (230) disposed to be recessed in the cool air duct and configured to allow air flow to bypass the evaporator (30); a sensor (270) including a heat generating element (273) disposed in the bypass passage (230) and a sensing element (274) configured to detect a temperature of the heat generating element (273); and a controller (40) configured to detect an amount of frost on an evaporator (30) based on a temperature difference value between a first detection temperature (Ht1) of the heat generating element (273) detected by the sensing element (274) in a state in which the heat generating element (273) is turned on and a second detection temperature (Ht2) of the heat generating element (273) detected by the sensing element (274) in a state in which the heat generating element (273) is turned off, wherein when the amount of frost on the evaporator (30) increases, the temperature difference value decreases.
  9. The refrigerator of claim 8, wherein the first detection temperature (Ht1) is a temperature detected by a sensing element (274) immediately after the heat generating element (273) is turned on.
  10. The refrigerator of claim 8, wherein the second detection temperature (Ht2) is a temperature detected by a sensing element (274) immediately after the heat generating element (273) is turned off.
  11. The refrigerator of claim 8, wherein the first detection temperature (Ht1) is a lowest temperature value during a period of time when the heat generating element (273) is turned on.
  12. The refrigerator of claim 8, wherein the second detection temperature (Ht2) is a highest temperature value after the heat generating element (273) is turned off.

Description

The present disclosure relates to a refrigerator and a control method thereof. [Background Art] JP S59 180 265 A relates to a device for detecting frost buildup in an evaporator in a refrigeration device such as a freezer or refrigerator which has an evaporator and an air circulation device such as a blower in a cooling compartment and cools the contents by circulating cold air. JP H01 312 378 A relates to a frost sensor provided between cooling fins in proximity to the fin, which comprises a thermistor as a temperature sensing element and a heater, and which is connected to plus and minus terminals of a comparator through resistances. When the heater is energized in an unfrosted condition, the resistance of the thermistor is lowered, whereas when the heater is energized in a frosted condition, the resistance is raised. CA 950 555 A relates to a frost detector for an air-cooling refrigeration system having an evaporator coil mounted in a main airflow duct being comprised of a first bypass duct connected to the main duct on each side of the coil and a second reference bypass duct connected to each side of a constriction in the outlet side of the main duct downstream from the coil. Refrigerators are household appliances that are capable of store objects such as foods at a low temperature in a storage chamber provided in a cabinet. Since the storage space is surrounded by heat insulation wall, the inside of the storage space may be maintained at a temperature less than an external temperature. The storage space may be classified into a refrigerating storage space or a freezing storage space according to a temperature range of the storage space. The refrigerator may further include an evaporator for supplying cool air to the storage space. Air in the storage space is cooled while flowing to a space, in which the evaporator is disposed, so as to be heat-exchanged with the evaporator, and the cooled air is supplied again to the storage space. Here, if the air heat-exchanged with the evaporator is contained in moisture, when the air is heat-exchanged with the evaporator, the moisture is frozen on a surface of the evaporator to generate frost on the surface of the evaporator. Since flow resistance of the air acts on the frost, the more an amount of frost frozen on the surface of the evaporator increases, the more the flow resistance increases. As a result, heat-exchange efficiency of the evaporator may be deteriorated, and thus, power consumption may increase. Thus, the refrigerator further includes a defroster for removing the frost on the evaporator. A defrosting cycle variable method is disclosed in Korean Patent Publication No. 2000-0004806 that is a prior art document. In the prior art document, the defrosting cycle is adjusted using a cumulative operation time of the compressor and an external temperature. However, like the prior art document, when defrosting cycle is determined only using the cumulative operation time of the compressor and the external temperature, an amount of frost (hereinafter, referred to as a frost generation amount) on the evaporator is not reflected. Thus, it is difficult accurately determine the time point at which the defrosting is required. That is, the frost generation amount may increase or decrease according to various environments such as the user's refrigerator usage pattern and the degree to which air retains moisture. In the case of the prior art document, there is a disadvantage in that the defrosting cycle is determined without reflecting the various environments. Moreover, in the case of the prior literature, there is a disadvantage that it is difficult to identify an exact defrost time point since the amount of local frost of the evaporator can be detected but the amount of frost on the entire evaporator cannot be detected. Accordingly, there is a disadvantage in that the defrosting does not start despite a large amount of generated frost to deteriorate cooling performance, or the defrosting starts despite a low frost generation amount to increase in power consumption due to the unnecessary defrosting. The invention is set out in the appended set of claims. Any references in the following description to embodiments, objects, aspects and/or examples which are not covered by the appended claims are considered as not being part of the present invention. An object of the present disclosure is to provide a refrigerator and a control method thereof, which determines a time point for a defrosting operation using parameters that vary depending on the amount of frost on an evaporator. In addition, an object of the present disclosure is to provide a refrigerator and a control method thereof, which accurately determine a time point at which defrosting is necessary according to the amount of frost on an evaporator using a sensor having an output value that varies depending on the flow rate of air. In addition, another object of the present disclosure is to provide a refrigerator and