Spectral-Splitting Solar Receiver for PV Cooling and Thermal Storage
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Solution Overview
Problem
Current solar energy conversion systems face challenges in achieving high efficiency and dispatchability, with photovoltaic (PV) systems being less dispatchable and concentrating solar power (CSP) systems being more costly, limiting their ability to replace traditional base load generation.
Innovation Solution
A single-stack solar power receiver is designed, comprising an optically transparent and thermally insulating (OTTI) layer, a spectrally selective high thermal conductivity (SSTC) thermal absorber layer with metallic fins coated to block specific solar radiation bands, and a PV cell layer, which splits the solar spectrum to minimize thermalization losses and direct usable radiation to the PV cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photovoltaic (PV) systems are used for solar energy conversion, then cost and conversion efficiency are improved, but dispatchability deteriorates
Solution Approach 1:
The solar spectrum is segmented into different wavelength ranges using spectrally selective coatings on thermal absorber layers. High-energy photons (UV and blue spectrum) are absorbed by the first thermal absorber layer, while lower-energy photons (red and infrared spectrum) pass through to the PV cells. This segmentation allows each component to operate in its optimal wavelength range, improving overall system efficiency while enabling thermal energy storage for dispatchability.
Solution Approach 2:
The patent merges PV cells with thermal absorber layers in a single integrated structure. The PV cells and thermal absorbers are positioned in close proximity within the same optical path, allowing simultaneous electricity generation and thermal energy capture from the same solar input. This merging enables the system to achieve both high conversion efficiency and dispatchability through thermal storage.
2Adaptability or versatility
If concentrating solar power (CSP) systems are used for solar energy conversion, then dispatchability is improved, but cost deteriorates
Solution Approach 1:
Different portions of the solar spectrum are directed to different components with locally optimized properties. The thermal absorber layers are positioned to absorb high-energy photons and are equipped with spectrally selective coatings tailored for those wavelengths, while PV cells are positioned to receive and convert lower-energy photons. This local quality optimization allows the system to achieve CSP-level dispatchability at reduced cost by utilizing efficient PV technology for the portion of the spectrum it handles best.
3Use of energy by moving object
If solar radiation is absorbed by thermal absorbers, then thermal energy is generated, but thermalization losses occur in PV cells
Solution Approach 1:
High-energy photons that would cause thermalization losses in PV cells are extracted and absorbed by the thermal absorber layers positioned in front of the PV cells. The spectrally selective coatings on the thermal absorbers are designed to selectively absorb UV and blue spectrum photons while allowing red and infrared photons to pass through to the PV cells. This extraction prevents the thermalization losses that would occur if high-energy photons were absorbed directly by the PV cells, converting them instead to useful thermal energy.
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 configuration enhances energy conversion efficiency by reducing thermalization losses in PV cells, allowing for the efficient conversion of solar radiation into electricity while maintaining the dispatchability of CSP systems, thereby improving the overall performance and cost-effectiveness of solar energy systems.
Implementation Method 1
an optically transparent and thermally insulating (OTTI) layer
Implementation Method 2
an optically transparent and thermally insulating (OTTI) layer
Implementation Method 3
a spectrally selective high thermal conductivity (SSTC) thermal absorber layer
Implementation Method 4
Solar energy absorbed by the fins is thermally conducted to the thermal working fluid in the pipes
Implementation Method 5
The fins may be made from or coated with a band-block material that decreases solar radiation absorption by the fins in the band where the PV cells are most sensitive
Implementation Method 6
a photovoltaic cell layer... Solar radiation reflected to the PV cell is transformed into electricity
Data Source
AI summary
A single-stack, solar power receiver comprising both a thermal absorber layer and a photovoltaic cell layer. The stack includes an aerogel layer, that is optically transparent and thermally insulating (“OTTI”); a spectrally selective high thermal conductivity (“SSTC”) thermal absorber layer; a bottom OTTI layer; and a PV cell layer. The SSTC layer includes a set of fins that substantially blocks solar radiation absorption in the band where PV cells are most sensitive. Photons with energies above or below this band block range are absorbed by the fins and the absorbed heat is conducted to pipes in the fin structure carrying a heated thermal working fluid to heat storage. Photons with energy in the band block range are reflected by the SSTC fins to the PV cell layer. The bottom OTTI aerogel layer keeps the PV cell operating near ambient temperature. The PV cell converts incident solar radiation to electrical energy.