Refrigerator and method of controlling same

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Solution Overview

Problem

Existing refrigerator defrosting cycles often start unnecessarily due to inaccurate determination of frost buildup, leading to increased power consumption as they do not account for user usage patterns and environmental factors.

Innovation Solution

A method for controlling a refrigerator that includes a compressor, evaporator, and defrosting heater, where a controller determines the defrosting start condition and delay based on accumulated cooling cycle time, door opening patterns, and temperature differences between the storage chamber and evaporator, allowing for delayed defrosting when conditions are met and immediate defrosting when not, thereby optimizing power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If defrosting is started based on fixed accumulated operation time and external air temperature, then defrosting cycle can be controlled, but unnecessary defrosting occurs when actual frosting amount is small, leading to increased power consumption

Engineering Contradiction:
Improvedefrosting control accuracyVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent introduces a feedback mechanism by using the evaporator temperature sensed by the evaporator sensor to determine whether to start defrosting. The controller continuously monitors the evaporator temperature and compares it against a reference temperature to accurately determine the actual frosting amount, then adjusts defrosting initiation accordingly. This feedback loop prevents unnecessary defrosting operations while ensuring defrosting occurs when actually needed, thereby reducing power consumption while maintaining reliable defrosting control.

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If defrosting is delayed when conditions permit, then power consumption is reduced, but defrosting must be started timely when frost buildup affects heat exchange efficiency

Engineering Contradiction:
Improvepower consumptionVSAvoidheat exchange efficiency
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent implements a dynamic defrosting control strategy where the defrosting timing is continuously adjusted based on real-time evaporator temperature conditions. The controller dynamically determines whether to delay or initiate defrosting by monitoring the evaporator temperature against a reference temperature. When the evaporator temperature indicates significant frosting (temperature difference exceeds threshold), defrosting is immediately triggered to maintain heat exchange efficiency. When conditions permit, defrosting is delayed to reduce power consumption. This dynamic adjustment optimizes the balance between energy savings and maintaining productivity.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple parameters (door opening patterns, temperature differences) are considered for defrosting control, then defrosting accuracy is improved, but control system complexity increases

Engineering Contradiction:
Improvefrosting amount detection accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses the evaporator temperature as an intermediary parameter to indirectly measure the frosting amount on the evaporator surface. Instead of directly measuring frost thickness or weight, the system monitors the evaporator temperature through the evaporator sensor and infers the frosting condition from temperature differences. This intermediary approach provides accurate frosting detection without requiring complex direct measurement systems, thereby improving measurement precision while avoiding excessive control system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces unnecessary power consumption by delaying defrosting when possible and adjusting cooling power post-defrosting based on user patterns, ensuring efficient operation and minimizing energy waste.

Implementation Method 1

an evaporator sensor configured to sense temperature of the evaporator or temperature around the evaporator

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 2

a defrosting heater operating to defrost the evaporator

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

an evaporator that supplies cold air to the storage chamber. The air in the storage chamber flows into the space where the evaporator is disposed, and is then cooled by exchanging heat with the evaporator

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

When the air that exchanges heat with the evaporator contains water, the water condenses on the surface of the evaporator when the air exchanges heat with the evaporator, whereby frost is produced on the surface of the evaporator

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3660426B1Refrigerator and method of controlling same
Publication Date: 2021.06.23 LG ELECTRONICS INC
  • EP3660426B1 patent drawingFigure 1
  • EP3660426B1 patent drawingFigure 2
  • EP3660426B1 patent drawingFigure 3~4

AI summary

The present disclosure provides a method of controlling a refrigerator that includes a compressor, an evaporator to supply cold air to a storage chamber, a defrosting heater to defrost the evaporator, and a controller to control the defrosting heater. The method includes: operating a cooling cycle for cooling the storage chamber; determining whether a defrosting start condition is satisfied during operation of the cooling cycle; determining whether a defrosting delay condition is satisfied when the defrosting start condition is satisfied; and starting a defrosting operation when the defrosting delay condition is not satisfied, and starting the defrosting operation at a delayed defrosting start time when the defrosting delay condition is satisfied.