Roll-Bond Evaporator with Integrated Heating Wire for Rapid Defrosting

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Solution Overview

Problem

Direct cooling type refrigerators with roll-bond type evaporators face challenges in frost removal due to increased contact resistance and reduced cooling efficiency, leading to longer defrosting times that compromise food freshness and increase power consumption.

Innovation Solution

A roll-bond type evaporator with a heating wire heater integrated into the case, allowing for efficient heat transfer to melt frost without the need for external defrosting heaters, reducing defrosting time and enhancing cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a refrigerant tube is attached on the heat-exchange plate, then the defrosting function is provided, but the contact resistance between the refrigerant tube and the heat-exchange plate increases, reducing cooling effect

Engineering Contradiction:
Improvefrost removal capabilityVSAvoidcooling effect
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The heating function is extracted from the refrigerant tube system and implemented through a separate heating wire heater that is inserted into the evaporator case. This separates the cooling function (performed by the refrigerant tube) from the heating/defrosting function (performed by the heating wire), eliminating the conflict between these opposing thermal functions and resolving the contact resistance issue that reduced cooling efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

2Volume of stationary object

If the heat-exchange plate is designed into multiple steps, then the freezing chamber capacity is ensured, but the welded portion of the refrigerant tube increases, complicating mass production

Engineering Contradiction:
Improvefreezing chamber capacityVSAvoidmass production feasibility
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

The evaporator case is segmented into multiple steps or levels, creating distinct zones that accommodate different functions and improve freezing chamber capacity. This segmentation is achieved through the case structure itself rather than through complex refrigerant tube welding, allowing for easier mass production while maintaining adequate storage volume.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If the heat-exchange plate is designed into one step, then the manufacturing is simplified, but the cooling effect is reduced due to convection current causing cold air to flow downward

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcooling effect
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The evaporator case is designed with localized variations in height, creating a multi-step structure where different regions serve different purposes. The stepped design creates localized cold air accumulation zones that prevent unwanted convection currents while maintaining overall manufacturing simplicity. This local structural modification optimizes cooling effectiveness without requiring complex overall design.

Inventive Principle:
Principle #3Local quality

4Device complexity

If natural defrosting is executed for a predetermined time, then the frost is removed without additional heating equipment, but the defrosting time is long, compromising food freshness

Engineering Contradiction:
Improvedefrosting equipment simplicityVSAvoiddefrosting time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The heating wire heater is integrated directly into the evaporator case structure, allowing the system to perform its own defrosting function efficiently. The heating wire is positioned to directly contact or closely approach the evaporator surfaces, enabling rapid frost removal without requiring external defrosting equipment or extended defrosting cycles, thus maintaining food freshness.

Inventive Principle:
Principle #25Self-service

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

The integrated heating wire heater reduces defrosting time, maintains food freshness, and decreases power consumption by efficiently using heat to remove frost, while allowing for mass production through a simple fabrication process.

Implementation Method 1

a heating wire heater inserted into the heating tube to surround the evaporator case, and generating heat, in response to power supplied

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an evaporator cooling surrounding air by a cooling operation that refrigerant introduced from the condenser absorbs latent heat while evaporated

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

refrigerant introduced from the condenser absorbs latent heat while evaporated

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 4

a condenser condensing high-temperature and high-pressure refrigerant compressed in the compressor in a manner of radiating heat

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 5

a condenser condensing high-temperature and high-pressure refrigerant compressed in the compressor in a manner of radiating heat

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 6

cold air flows downward due to a convection current

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3435001B1Evaporator and refrigerator having same
Publication Date: 2020.12.30 LG ELECTRONICS INC
  • EP3435001B1 patent drawingFigure 1
  • EP3435001B1 patent drawingFigure 2~3
  • EP3435001B1 patent drawingFigure 4

AI summary

The present disclosure relates to an evaporator, including an evaporator case formed in a box shape with both sides open in a manner of bending two case sheets coupled to each other, a cooling tube left as an empty space between the two case sheets to form a cooling passage for a flow of refrigerant, a heating tube left as an empty space between the two case sheets in a non-overlapping manner with the cooling tube, and a heating wire heater inserted into the heating tube to surround the evaporator case, and generating heat, in response to power supplied, such that heat for defrosting is transferred to the evaporator case.