Nanostructured Solar Collector Surface for Stable Light Absorption
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Solution Overview
Problem
Existing solar collectors face inefficiencies due to unstable polymer coatings and additional environmentally harmful chemical processes for heat transfer surfaces, which lead to reduced thermal energy absorption and radiation efficiency.
Innovation Solution
A solar collector with a nanostructured light-absorbing surface created by integrating titanium dioxide nanoparticles into the surface during the controlled atmosphere brazing (CAB) soldering process, eliminating the need for post-coating applications and enhancing light and infrared absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If polymer coatings are applied to heat transfer surfaces, then light absorption is improved, but long-term stability deteriorates due to instability in sunlight
Solution Approach 1:
The patent replaces unstable polymer coatings with a black oxide layer formed through controlled oxidation of the aluminum substrate itself. The aluminum surface is treated to create a natural, stable black oxide coating that does not degrade in sunlight, eliminating the need for protective polymer layers while maintaining high light absorption.
Solution Approach 2:
The patent changes the surface properties of aluminum through controlled oxidation parameters, creating a black oxide layer with specific thickness and composition. By adjusting oxidation conditions (time, temperature, chemical composition), the surface achieves optimal light absorption while maintaining long-term stability without polymer coatings.
2Use of energy by moving object
If galvanic coatings or painting processes are used for absorber surfaces, then light absorption is improved, but manufacturing complexity increases due to additional subsequent processes
Solution Approach 1:
The patent combines the surface treatment process with the base material preparation step. The black oxide layer is formed directly on the aluminum substrate during or before the brazing process, merging multiple functions (surface preparation, light absorption enhancement, and protective coating) into a single integrated process, thereby reducing manufacturing complexity.
Solution Approach 2:
The aluminum substrate serves its own dual function: it provides both the structural base material and the light-absorbing surface through its naturally formed black oxide layer. This self-service approach eliminates the need for separate coating applications, reducing manufacturing steps and complexity.
3Reliability
If chromating or chemical treatments are applied to heat transfer surfaces, then adhesion is improved, but environmental harm increases due to use of harmful chemicals
Solution Approach 1:
The patent converts the naturally occurring oxidation of aluminum (which would normally be considered a defect or unwanted surface degradation) into a beneficial black oxide coating. This controlled oxidation process creates a stable, adhesive surface without requiring harmful chromating chemicals, thus converting a potential harm into a benefit while eliminating environmental pollution.
Solution Approach 2:
The patent uses controlled oxidation environments (such as aqueous solutions with specific pH and composition, or controlled atmospheric conditions during brazing) to form the black oxide layer without introducing harmful chemicals. The process occurs in environmentally benign conditions, replacing toxic chromating treatments with inert or mildly reactive solutions.
4Use of energy by moving object
If additional coating layers are applied to metal surfaces, then light absorption is improved, but thermal energy transfer efficiency deteriorates due to interface resistance
Solution Approach 1:
The patent creates a black oxide layer with a porous or rough surface structure that significantly enhances light absorption through multiple reflections and trapping effects. This porous structure increases the effective surface area for light absorption while maintaining direct thermal contact with the base metal, thereby improving light absorption without creating significant thermal resistance.
Solution Approach 2:
The patent creates a composite structure where the black oxide layer is chemically bonded to the aluminum substrate, forming an integrated material system. This composite structure combines the high light absorption properties of the black oxide with the excellent thermal conductivity of aluminum, achieving both high light absorption and efficient heat transfer without interface resistance.
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 nanostructured surface achieves high light absorption and efficient heat transfer with reduced interface resistance, improving energy absorption and radiation capabilities, particularly in solar energy technology.
Implementation Method 1
the nanostructured layer consisting of nanoparticles of an inorganic material... solar energy, ie light and infrared radiation, can be absorbed via the light-absorbing surface
Implementation Method 2
use of a surface for light absorption or for heat radiation
Implementation Method 3
The absorption of solar energy can lead to heating of the base material and the coolant
Data Source
Figure 1~2
AI summary
The present invention relates to a solar collector having a base material (101) and a nanostructured layer (103) integrated into the base material (101) so as to form a light-absorbing surface. The nanostructured layer consists of nanoparticles of an inorganic material.