Multi-Layer Anti-Stokes Fluorescence Cooling for Solar Radiation
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Solution Overview
Problem
Current anti-Stokes based cooling technologies are limited by the requirement for excitation by laser and tuning to very specific radiation wavelengths, making them inefficient for larger scale applications and non-monochromatic radiation conditions.
Innovation Solution
The use of semiconductor materials for wide band-gap anti-Stokes cooling under wide spectrum solar radiation, where a double- or multi-layer structure filters incoming radiation to transmit only a selected band to an active cooling layer that exhibits anti-Stokes fluorescence, allowing for efficient cooling without the need for precise wavelength tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If laser cooling with narrow wavelength range is used, then cooling efficiency is improved, but device complexity and cost increase due to requirement for precise wavelength tuning and laser equipment
Solution Approach 1:
The patent changes the spectral response parameters of the cooling material by using semiconductor quantum wells with specific band gap energies. This allows the material to respond to a broader range of solar wavelengths without requiring precise wavelength tuning, thereby reducing device complexity while maintaining cooling efficiency through quantum confinement effects
Solution Approach 2:
The patent replaces expensive laser equipment with inexpensive solar radiation sources. By using semiconductor materials that can be deposited as thin films and respond to broad solar spectrum, the system eliminates the need for costly laser systems while achieving effective cooling through anti-Stokes fluorescence
2Measurement precision
If laser cooling with monochromatic radiation is used, then cooling precision is improved, but adaptability to different radiation conditions deteriorates
Solution Approach 1:
The patent creates a universal cooling solution by developing semiconductor-based materials that can function under various radiation conditions (direct sunlight, diffuse light, different times of day). The quantum well structure provides broad spectral response, making the cooling system adaptable to different environmental conditions without requiring precise wavelength matching
3Temperature
If traditional laser cooling is used for small scale applications, then cooling effectiveness is improved, but scalability to larger objects deteriorates
Solution Approach 1:
The patent segments the cooling function into distributed semiconductor quantum well structures that can be applied across large surfaces. These quantum wells are deposited as thin films on substrates, allowing the cooling effect to be scaled from small to large areas by simply increasing the surface area covered with the semiconductor layer
Solution Approach 2:
The patent uses composite semiconductor structures (quantum wells within a matrix material) that combine the cooling properties of semiconductors with the mechanical and optical properties of host materials. This composite approach enables scalable application to large objects while maintaining effective cooling through the anti-Stokes fluorescence mechanism
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 approach enables effective cooling of larger scale objects and surfaces using incoherent solar radiation, intensifying the cooling effect by filtering the radiation spectrum and utilizing materials that respond to a range of wavelengths, thus overcoming the limitations of traditional laser cooling technologies.
Implementation Method 1
Laser cooling of solids is a phenomenon in which interaction with radiation is causing effective cooling in solid materials... Anti-Stokes fluorescence/scattering, which is the opposite of Stokes fluorescence... In this process, light interacts with matter so that each photon is scattered with more energy than the energy it started with. The energy is provided by the phonons in the material, leading to cooling of the material after equilibration.
Implementation Method 2
In this process, light interacts with matter so that each photon is scattered with more energy than the energy it started with. The energy is provided by the phonons in the material, leading to cooling of the material after equilibration.
Implementation Method 3
The use of semiconductor materials for wide band-gap anti-Stokes cooling under wide spectrum solar radiation, where a double- or multi-layer structure filters incoming radiation to transmit only a selected band to an active cooling layer
Implementation Method 4
semiconductor materials for wide band-gap anti-Stokes cooling under wide spectrum solar radiation
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4
AI summary
A double or multi- layer apparatus or device for optical anti-Stokes cooling of object surfaces. The apparatus comprises at least one bottom layer, which is configured to respond in anti-Stokes fluorescence upon absorption of electromagnetic radiation and at least one top layer, which is overlaid on the bottom layer and configured to filter the electromagnetic radiation and transmit selected spectral band of the electromagnetic radiation to the bottom layer. The active cooling does not depend on the coherent nature of the radiation, which enables the usage of incoherent solar radiation as the active cooling input power source. The cooling technology of the invention is suitable for small and large scales and practically for any object with surface on which the layer substance can be applied or overlaid, e.g., roof, wall, car, ship, tent, clothing, etc.