Solar Collector Coating Calcination Using Induction Heating

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Solution Overview

Problem

Conventional calcination methods for solar collector coatings are inefficient, leading to temperature inhomogeneity, low yield, and poor quality coatings due to the need for large enclosures and complex airlock systems, which result in inhomogeneous coatings and blister formation.

Innovation Solution

The use of induction heating to rapidly and homogeneously heat tubular substrates by creating an induced current through an induction coil, allowing for precise temperature control and continuous heating of a small region, thereby avoiding the formation of blisters and ensuring good adhesion of the coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional calcination in a large enclosed chamber is used, then the coating can be heated, but temperature inhomogeneity occurs and production efficiency is low

Engineering Contradiction:
Improvetemperature uniformityVSAvoidcalcination speed
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent divides the calcination process into localized zones using multiple heating zones along the tubular substrate path, allowing different regions to be heated independently and simultaneously, achieving both temperature uniformity and high production efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces conventional thermal conduction heating with induction heating technology, using electromagnetic fields to directly heat the tubular substrate and coating, eliminating temperature gradients and enabling rapid, uniform calcination

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If rapid heating is applied to increase production rate, then productivity improves, but the coating forms blisters and quality deteriorates

Engineering Contradiction:
Improvecalcination speedVSAvoidcoating quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses induction heating to provide rapid, uniform, and controllable heating that eliminates the thermal gradients causing blister formation, achieving both high productivity and high coating quality simultaneously

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent precisely controls heating parameters including temperature, heating rate, and residence time through automated systems, optimizing the calcination process to prevent coating defects while maintaining high production speed

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If a large enclosed chamber is used for calcination, then the entire tube can be processed, but energy losses increase and system complexity increases

Engineering Contradiction:
Improveprocessing capacityVSAvoidenergy efficiency
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent extracts the heating function from a large enclosed chamber and implements it directly on the tubular substrate through induction heating, eliminating the need for large energy-consuming chambers and airlock systems while maintaining full tube processing capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The tubular substrate itself serves as the heating element through induction heating, where the substrate's electrical conductivity allows direct electromagnetic heating, eliminating the need for external heating chambers and associated energy losses

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

This method enables efficient, high-quality, and homogeneous calcination of solar collector coatings with real-time temperature monitoring, reducing energy losses and improving production efficiency by focusing energy directly on the substrate, resulting in a durable and optically selective multi-coating structure.

Implementation Method 1

The use of induction heating to rapidly and homogeneously heat tubular substrates by creating an induced current through an induction coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The use of induction heating to rapidly and homogeneously heat tubular substrates by creating an induced current through an induction coil

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2898113B1Method for hardening a coating of a solar collector element
Publication Date: 2021.02.17 ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE (EPFL)
  • EP2898113B1 patent drawingFigure 1
  • EP2898113B1 patent drawingFigure 2~3
  • EP2898113B1 patent drawingFigure 4~6

AI summary

The invention relates to a method for hardening a coating of a solar collector element, said element including a conductive material or a conductive layer. The invention is characterised in that the coating is hardened by induction heating.