Corrugated Plastic Refrigeration Circuit for Flexible Heat Exchange

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Solution Overview

Problem

Traditional refrigeration circuits for household appliances face challenges such as limited operating flexibility, high production costs, environmental pollution, and weight due to metal coils, along with issues of gas leaks and insufficient thermal exchange efficiency.

Innovation Solution

A refrigeration circuit using corrugated plastic tubing with a multilayer extrusion process for improved flexibility, thermal exchange efficiency, and impermeability, replacing metal coils with plastic materials for reduced weight and production complexity, and incorporating corrugated profiles for enhanced turbulence and noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If metal coils are used for thermal exchange, then thermal exchange efficiency is improved, but weight and production cost increase

Engineering Contradiction:
Improvethermal exchange efficiencyVSAvoidweight of refrigeration system
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent changes the material parameter from metal to plastic, specifically using polyamide 6-6 or polyamide 12 for the tubing. This material substitution reduces weight while maintaining functional performance through optimized wall thickness (0.4-1.5mm) and corrugated geometry that enhances thermal exchange capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite structure by combining plastic material with corrugated geometry. The corrugated profile creates increased surface area and turbulence promotion, compensating for the lower thermal conductivity of plastic compared to metal, thus achieving efficient thermal exchange without metal.

Inventive Principle:
Principle #40Composite materials

2Area of stationary object

If metal tubes are bent and welded to create coils, then thermal exchange surface is increased, but production complexity and cost increase

Engineering Contradiction:
Improvethermal exchange surfaceVSAvoidproduction process complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent extracts the complex metal tube bending and welding operations from the production process. By using extruded plastic tubing with integrated corrugated geometry, the need for post-extrusion bending and welding is eliminated, significantly simplifying manufacturing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The corrugated geometry is built into the tubing during the extrusion process itself, rather than being added later through bending operations. This preliminary formation of the thermal exchange surface structure eliminates subsequent complex manufacturing steps.

Inventive Principle:
Principle #10Preliminary action

3Strength

If metal tubes are used, then structural strength is improved, but corrosion resistance requires additional chemical treatments

Engineering Contradiction:
Improvestructural strengthVSAvoidchemical pollution from treatments
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent uses plastic material that inherently resists corrosion without requiring protective coatings or chemical treatments. While plastic has lower strength than metal, the corrugated structure and optimized wall thickness provide sufficient structural integrity for refrigeration applications, eliminating the need for environmentally harmful chemical treatments.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Manufacturing precision

If rigid metal coils are used, then manufacturing precision is improved, but adaptability to different geometries deteriorates

Engineering Contradiction:
Improvecoil geometry precisionVSAvoidadaptability to different surfaces
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent transforms the rigid metal coil into a flexible plastic tube that can be dynamically configured. The corrugated plastic tubing can be bent and shaped to adapt to various geometric requirements of different refrigeration system designs, providing both precision and versatility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs flexible corrugated plastic tubing instead of rigid metal coils. The flexibility allows the tubing to be configured into different geometries while maintaining manufacturing precision through controlled extrusion processes, enabling adaptation to various thermal exchange surface requirements.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution provides a more flexible, cost-effective, and environmentally friendly refrigeration system with improved thermal exchange efficiency, reduced weight, and enhanced impermeability, addressing the limitations of traditional metal coil-based systems.

Implementation Method 1

The corrugated profile allows the turbulence of the cooling fluid to be promoted so as to improve the thermal exchange made by the circuit

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

a refrigerating means which is suitable for undergoing a passage of state from liquid to vapour by expansion with the effect of subtracting heat to the ambience it is in contact with

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

transferring it towards the outer warmer space

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP2350541B1Refrigeration circuit
Publication Date: 2016.06.08 INDISTRIE ILPEA SPA
  • EP2350541B1 patent drawingFigure 1
  • EP2350541B1 patent drawingFigure 2
  • EP2350541B1 patent drawingFigure 3~4

AI summary

A refrigeration circuit (3) for household appliances comprises a compressor (4) suitable for compressing a predetermined cooling fluid and for allowing circulation thereof within said circuit (3), a first heat exchanger (5) or condenser in fluid communication with the compressor (4) for allowing cooling and the consequent condensation of the cooling fluid going therethrough, and a second heat exchanger (7) or evaporator in fluid communication with the first exchanger (5) through a circuit with a special device (6) suitable for decreasing the pressure of the cooling fluid and acting at a space (2) to be cooled (normally inside the refrigerator). The second exchanger (7) allows the cooling fluid to evaporate, by heat absorption, thus cooling the space (2) and returning through the tubing (17) to the compressor (4). The cooling fluid circulates from the compressor (4) towards the first exchanger (5), from the latter towards the second exchanger (7), then returning to the compressor (4) for a subsequent cycle. At least one of the heat exchangers (5, 7) comprises a plastic tubing (9), at least one portion whereof exhibits such a corrugated profile as to impart flexibility thereto and/or increase the thermal exchange surface. The tubing in section exhibits a structural layer (100) of plastic material and a layer (101) comprising a film of metal material adapted to constitute a barrier against humidity and gases in general, such shaped as to maintain the tube flexibility.