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
• • 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
  • F25D17/00—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces
  • F25D17/04—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection
  • F25D17/06—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection by forced circulation
  • F25D17/062—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection by forced circulation in household refrigerators
  • F25D17/065—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection by forced circulation in household refrigerators with compartments at different 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
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D2400/00—General features of, or devices for refrigerators, cold rooms, ice-boxes, or for cooling or freezing apparatus not covered by any other subclass
  • F25D2400/04—Refrigerators with a horizontal mullion

Definitions

• the present invention is related to starting a defrosting operation in the refrigerators by evaluating the temperature values obtained by two temperature 5 sensors disposed in the freezer compartment.
• detrosting is eltected periodically to melt the accumulated Irost De osting c cles eltected before required.
• the decision for defrosting is taken according to the 0 running penod of the compressor
• a timer controls the running period of the compressor and the decision for defrosting is taken when the defined pe ⁇ od is completed
• this difference value is greater than a given comparison value, a certain time period is provided, and at the end of this period, decision for defrosting is taken when the said difference value increases with a defined temperature and when the temperature of the fluid entering the evaporator, exceeds a defined value, the defrost operation is terminated.
• a defrosting decision with warning is taken by using at least one or two temperature sensors connected with each other in series, and an electronic control unit.
• the sensors are the semiconductor circuits sensing the temperature inside the refrigerator and they are connected to the electronic control unit.
• the sensor is placed inside the compartment.
• defrosting is started.
• first sensor is placed on the evaporator and the second is placed inside the compartment.
• the decision for defrosting is given according to the temperature outside the cooler, also considering the differences between the rates of variations in temperature falls on the evaporator under frost or no-frost conditions.
• the time interval required for cooling the air inside the refrigerator also depends on the ambient temperature.
• a temperature sensor is placed in the refrigerator, on the evaporator or somewhere else, in order to obtain a reference for cooling time.
• the time interval spent to attain the desired temperature in the refrigerator when the compressor starts to operate, is called the cooling time. This time interval depends on the ambient temperature and the amount of frost load deposited on the evaporator.
• the time interval required for defrosting, as calculated when the compressor is not switched on, is less accurate than that calculated while the compressor is working.
• the decision for defrosting is taken similar to the US Patent No. 5257506, but the decision is taken when the difference between the temperature on the evaporator and the ambient temperature exceeds a certain threshold value.
• the method used is related to the employment of defrosting adaptive to heat pumps, and consists of devices measuring the amount of frost deposited on the heat pump and consists of devices measuring the amount of frost deposited on the heat pump.
• defrosting operation is started when the difference between the ambient temperature and the temperature on the evaporator exceeds the value of a function depending on the external, ambient temperature.
• the defrosting time is measured, in case the time interval deviates from the predetermined period, the difference function is determined with respect to the ambient temperature, changes.
• the difference function for a certain ambient temperature used for the calculation of the quantity of frost that has been defined linearly at the beginning, can be drawn upwards or downwards depending on whether the defrosting time is longer or shorter than determined threshold values.
• the decision for defrosting is taken for a heat pump. Defrosting is started according to the temperature measured by a sensor on the evaporator and to the temperature of the fluid in the evaporator.
• the rate of change of the temperature on the evaporator during a defrosting cycle the time interval when the rate of change of the temperature of the evaporator remains constant and the duration of the cooling cycle depending on the determined time interval, are used.
• the determined time interval is indicative of the magnitude of next cooling cycle is calculated according the said magnitude of the frost load deposited on the evaporator.
• the freezer and cooling compartments of the refrigerator are cooled separately and independently. If the temperature in the cooling compartment exceeds a predefined temperature, defrosting cycle is started according to the operational conditions of the compressor and the fan. The starting time for defrosting in the cooling compartment is determined according to the decrease of the temperature value inside the compartment, the same criteria are valid for the freezer compartment.
• the difference values between the evaporation temperature of the fluid contained in the evaporator and its temperature when leaving of the refrigerator, or the difference between air entrance temperature or air entrance temperature and the evaporation temperature, are used.
• This difference value obtained the fluid temperature measured when leaving the refrigerator and the evaporation temperature values are used to open and close the expansion valve.
• the difference between air inlet temperature and vaporization temperature is used for calculation of ideal defrost time interval.
• the decrease in the flow, in a certain predetermined time range is calculated accordingly. Under the light of these two criteria if the two threshold values are exceeded, the operation of the compressor and fan are stopped and the defrost heater is operated until the refrigerator attains the ambient temperature indicating that the frost deposited on the evaporator has melted.
• the object of the present invention is to provide a decision taking for starting the defrosting cycle in the refrigerators, according to the operation of the compressor and to the temperature values obtained by the two temperature sensors placed in the freezer compartment, also by considering such factors that influence the operational performance of the refrigerator, as different user habits and behaviours and different loading conditions.
• Figure 1 is the general view of the refrigerator with the sensors placed on the evaporator and on the blowing area of the fan;
• Figure 2 is the side view showing the freezer compartment of the refrigerator and the sensors;
• Figure 3 is the flow chart of the defrost control.
• Temperature sensor placed on the freezer evaporator fluid entrance zone 4. Temperature sensor placed on the flow area over the evaporator air discharge channel, wherein the cooled air is blown by a fan,
• the evaporator (1), fan (2) and two temperature sensors (3 and 4) are placed in an intermediate compartment in the freezer compartment (5) of a refrigerator with two compartments.
• One of the said sensors is disposed on the freezer evaporator (1) fluid inlet zone, and the other is placed at the flow area on the evaporator (1) air exit channel wherein the cooled air is blown by a fan (2).
• the temperature value detected by the sensor (4) placed at the flow area on the evaporator (1) air exit channel wherein the cooled air is blown by a fan (2) is shown as (Tl) and the temperature value detected by the sensor (3) disposed on the freezer evaporator (1) fluid inlet zone is shown as (T2).
• Tl The temperature value detected by the sensor (4) placed at the flow area on the evaporator (1) air exit channel wherein the cooled air is blown by a fan (2)
• the temperature value (T2) detected by the sensor (3) disposed on the freezer evaporator (1) fluid inlet zone are read during the time interval (t2) determined by the manufacturer.
• the temperature difference value ( ⁇ T) is compared to a threshold value ( ⁇ T threshold) determined by the manufacturer and if the calculated temperature difference value ( ⁇ T) is smaller than the threshold value ( ⁇ T threshold), it is turned to the first operational step wherein the running of the compressor is checked. If the calculated temperature difference value ( ⁇ T) is greater than the threshold value ( ⁇ T threshold), the defrosting cycle is initiated.
• ⁇ T threshold a threshold value determined by the manufacturer

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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)
• Cold Air Circulating Systems And Constructional Details In Refrigerators (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=21622171

Family Applications (1)

Country Status (3)

Cited By (3)

Citations (5)

• 2000
  • 2000-09-25 TR TR2002/00796T patent/TR200200796T2/tr unknown
  • 2000-09-25 WO PCT/TR2000/000051 patent/WO2001022014A1/en active Application Filing
  • 2000-09-25 AU AU76990/00A patent/AU7699000A/en not_active Abandoned

Patent Citations (5)

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