Ceramic Solar Absorber Channel Geometry for Lower Reflective Loss

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Solution Overview

Problem

Existing absorber bodies for solar radiation in solar thermal power plants have high reflectivity due to limitations in reducing wall thickness, leading to inefficient absorption of solar radiation.

Innovation Solution

A method for producing ceramic absorber bodies involves material-removing processing of the green absorber body to increase the surface area for absorption, specifically by forming inclined jet entry surfaces in the channels, which are milled or sandblasted to enhance radiation absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the wall thickness of the absorber body is reduced to increase absorption surface area, then the absorption of solar radiation is improved, but the mechanical strength and structural stability deteriorate

Engineering Contradiction:
Improveabsorption of solar radiationVSAvoidmechanical strength of absorber body
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The absorber body is divided into a modular structure consisting of a support body with integrated channels. This segmentation allows the thin-walled channel structures to be supported by the robust support body, enabling reduced wall thickness for increased absorption surface area while maintaining overall structural strength through the modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The channels are pre-formed as integral parts of the support body during the manufacturing process (injection molding or extrusion), rather than being added later. This preliminary action ensures that the thin-walled channels maintain their structural integrity through proper material distribution and reinforcement at critical locations during the forming process.

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If sandblasting is used to reduce the front surface area of the absorber body, then the reflective surface is reduced and absorption is improved, but the manufacturing precision and reproducibility deteriorate

Engineering Contradiction:
Improveabsorption of solar radiationVSAvoidreproducibility of wall thickness reduction
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The reduced front surface area of the channels is built into the support body during the injection molding or extrusion process. This preliminary formation of the channel geometry ensures consistent, reproducible wall thickness reduction without relying on variable sandblasting processes, achieving both the desired absorption improvement and manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The mechanical sandblasting process is replaced with a precision molding process that directly forms the desired channel geometry. This substitution eliminates the variability and imprecision inherent in sandblasting while achieving the same functional result of reduced front surface area for improved radiation absorption.

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

3Use of energy by moving object

If the front surface area of the absorber body is reduced to increase radiation penetration, then the absorption efficiency is improved, but the reflective losses increase

Engineering Contradiction:
Improveradiation absorption efficiencyVSAvoidreflective energy loss
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The channel structures extend in the depth dimension of the absorber body, providing multiple reflection surfaces at different depths. This dimensional approach allows radiation that penetrates the reduced front surface to be captured through multiple internal reflections along the channel length, converting what would be reflective losses into absorbed energy.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The channel walls are positioned to create localized absorption zones throughout the absorber body depth. By distributing the absorption function across multiple locations along the channel length rather than concentrating it at the front surface, the design captures radiation at various depths, reducing overall reflective losses while maintaining efficient absorption.

Inventive Principle:
Principle #3Local quality

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 method significantly reduces the reflective surface area, allowing for increased absorption of solar radiation and efficient conversion into heat, resulting in highly efficient absorber bodies.

Implementation Method 1

forming inclined jet entry surfaces in the channels, which are milled or sandblasted to enhance radiation absorption

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

the heat obtained in a large number of absorber bodies by absorbing concentrated solar radiation

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 3

material-removing processing of the green absorber body to increase the surface area effective for absorption, specifically by forming inclined jet entry surfaces in the channels, which are milled or sandblasted

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP2384270B1Method for the production of a ceramic absorber member for solar radiation
Publication Date: 2021.08.25 SAINT GOBAIN INDUSTRIE KERAMIK RODENTAL GMBH
  • EP2384270B1 patent drawingFigure 1~3
  • EP2384270B1 patent drawingFigure 4~5
  • EP2384270B1 patent drawingFigure 6

AI summary

The invention relates to a housing (80) for a solar absorber module (8) for a solar thermal power plant, comprising a first tapered housing section (81) that has a first free end (82) for accommodating a ceramic solar absorber element (9) and a second end (83) which has a smaller cross-sectional area than the first end (82), and a second housing section (84) that has a substantially constant cross-section along its length. The second housing section (84) adjoins the second end (83) of the first housing section (81). According to the invention, the housing (80) is characterized in that a wall (85) that has a plurality of openings (86) and extends across the entire internal cross-section of the first housing section (81) is arranged in the first tapered housing section (81). The invention further relates to a method for producing such a housing (80) and a method for fastening the housing (80) to a support structure (11).