Stimuli-Responsive Waveguide for Self-Aligned Solar Concentration
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Solution Overview
Problem
Existing waveguide-type solar energy harvesting devices require mechanical tracking to align with the sun, which increases costs and complicates integration into building envelopes, and prior art concentrators face limitations in achieving high concentration factors without mechanical tracking.
Innovation Solution
A lightguide-type solar energy harvesting device utilizing a stimuli-responsive material (SRM) dispersed throughout the waveguide structure that generates self-aligned light scattering structures, allowing sunlight to be concentrated internally without the need for mechanical tracking, by changing from a transparent to an opaque state when exposed to sufficient solar radiation, thereby redirecting light to a photovoltaic cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical tracking is used to align waveguide-type solar energy harvesting devices with the sun, then light concentration efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The waveguide material contains dispersed stimuli-responsive particles that automatically change their light scattering properties in response to concentrated sunlight, creating self-aligned light scattering structures without requiring external mechanical tracking systems. The system serves itself by using the concentrated solar energy to trigger the optical property changes needed for continued efficient light concentration.
Solution Approach 2:
The stimuli-responsive particles undergo changes in their optical parameters (light scattering cross-section) in response to temperature or light intensity changes caused by concentrated sunlight. This dynamic parameter change allows the material to adapt its light guiding properties automatically, replacing the need for mechanical alignment adjustments.
2Productivity
If mechanical tracking systems are installed, then solar energy capture is improved, but ease of integration into building envelopes deteriorates
Solution Approach 1:
The waveguide material with dispersed stimuli-responsive particles automatically adapts to the sun's position through self-aligned light scattering structures, eliminating the need for mechanical tracking systems. This makes the device statically installable and easily integrable into building envelopes while maintaining high solar energy capture through the self-adjusting optical properties of the material.
3Device complexity
If stimuli-responsive material is dispersed throughout the waveguide structure, then mechanical tracking is eliminated, but manufacturing precision requirements increase
Solution Approach 1:
The stimuli-responsive particles are dispersed throughout the waveguide material, creating local optical property changes only in the regions where concentrated sunlight reaches. This localized response means that precise alignment is not needed globally, but only locally at the particle level, which is achieved through dispersion rather than precise positioning.
Solution Approach 2:
The dispersed stimuli-responsive particles change their optical parameters dynamically in response to concentrated light, compensating for variations in manufacturing precision. The material's adaptive optical properties ensure effective light concentration even with tolerances in the positioning of particles or waveguide components.
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 solution eliminates the need for mechanical tracking and prism/mirrored facets, enhancing light transmission and concentration efficiency while maintaining transparency to diffuse light, allowing for a self-adjusting solar transmission system that can serve both as a power source and a skylight, reducing installation and maintenance costs.
Implementation Method 1
a stimuli-responsive material (SRM), such as a phase-change material (PCM) having a lower critical solution temperature (LCST) slightly above room temperature
Implementation Method 2
generates self-aligned light scattering structures
Implementation Method 3
waveguide-type concentrating solar energy harvesting devices
Implementation Method 4
Photovoltaic (PV) cells are used to convert solar energy (sunlight) into electricity
Data Source
AI summary
A solar energy harvesting system including a sunlight concentrating member (e.g., a lens array) for focusing direct sunlight at predetermined focal points inside a waveguide containing a stimuli-responsive material (SRM) that is evenly distributed throughout the waveguide material such that the SRM assumes a relatively high transparency state away from the focused sunlight, and small light-scattering portions of the SRM change to a relatively opaque (light scattering) state only in focal zone regions adjacent to the concentrated sunlight. The outer waveguide surfaces are locally parallel (e.g., planar) and formed such that sunlight scattered by the light-scattering SRM portions is transmitted by total internal reflection through the remaining transparent waveguide material, and outcoupled to one or more solar energy receivers (e.g., PV cells) that are disposed outside the waveguide (e.g., along the peripheral edge).