Solar Generator with Paraboloidal Reflector and Flat PV Arrays
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Solution Overview
Problem
Existing solar generators using multi-junction photovoltaic cells face high manufacturing costs and efficiency losses due to complex optical systems, uneven illumination, and mispointing issues, which lead to reduced power output and increased costs.
Innovation Solution
A solar electricity generation apparatus using a large paraboloidal mirror with back-silvered glass segments, dividing concentrated sunlight into equal regions for multiple small multi-junction photovoltaic cells, with secondary optics that include telecentric lenses and sharp-edged wedges to ensure uniform illumination and balance, allowing for flat cell configurations and reduced manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If many small solar focusing optical systems are used for each individual photovoltaic cell, then high efficiency of multi-junction solar cells is exploited, but the packaged assemblies become large and complex with high cost
Solution Approach 1:
The invention divides the large paraboloidal reflector into multiple smaller reflector dishes, each focusing light onto a separate photovoltaic cell or small array of cells. This segmentation allows standardization of components, reducing manufacturing complexity and cost while maintaining high conversion efficiency of multi-junction cells.
Solution Approach 2:
The patent uses identical or similar photovoltaic cells and optical assemblies that can be replicated and tiled across multiple reflector dishes. This copying approach enables standardized manufacturing processes, reducing complexity and cost compared to custom-designed systems.
2Power
If a large paraboloidal reflector is used to concentrate sunlight, then high power generation is achieved, but uneven illumination and mispointing cause efficiency losses
Solution Approach 1:
By dividing the large reflector into multiple smaller dishes, each dish creates a more uniform illumination pattern on its corresponding photovoltaic cell. This segmentation also reduces the impact of mispointing, as each smaller reflector has a narrower field of view and is less sensitive to alignment errors, thereby reducing efficiency losses.
Solution Approach 2:
Each photovoltaic cell or small array is optimized to receive concentrated sunlight from its specific reflector dish, creating locally uniform illumination. The secondary optics in each assembly are tailored to distribute light evenly across the specific cell it serves, ensuring optimal local efficiency.
3Illumination intensity
If concave arrays with spherical symmetry are used to distribute light equally, then uniform illumination is achieved, but manufacturing costs increase due to curved surfaces and complex funnel shapes
Solution Approach 1:
Instead of using concave arrays with spherical symmetry to achieve uniform illumination, the invention inverts the approach by using flat or slightly curved photovoltaic cell arrays with secondary optics that actively distribute the concentrated sunlight uniformly across the cell surface. This inversion simplifies the reflector geometry while maintaining illumination uniformity through the secondary optical elements.
Solution Approach 2:
The patent changes the geometric parameters of the optical system, transitioning from spherical symmetry with concave surfaces to flatter geometries with adjusted optical paths. This parameter change simplifies manufacturing of reflector surfaces while achieving uniform illumination through modified light distribution mechanisms.
4Loss of energy
If stiff, heavy trackers are used to maintain accurate pointing, then mispointing losses are reduced, but system cost increases
Solution Approach 1:
By dividing the system into multiple smaller reflector dishes, each with its own simplified tracking mechanism, the patent reduces the complexity and cost of individual trackers. The segmented approach allows for less precise but simpler tracking systems compared to a single large reflector requiring heavy, stiff trackers.
Solution Approach 2:
The patent accepts partial mispointing of individual small reflectors without significant power loss, as the overall system maintains efficiency through the distributed architecture. This partial action approach eliminates the need for excessive tracking precision that would require heavy, expensive trackers.
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 solution achieves high efficiency and low manufacturing costs by ensuring equal light distribution across cells, maintaining balance despite mispointing, and using inexpensive, easily manufactured secondary optics, resulting in efficient power generation with reduced system losses.
Implementation Method 1
a large paraboloidal mirror with back-silvered glass segments
Implementation Method 2
concentrated sunlight into equal regions for multiple small multi-junction photovoltaic cells
Implementation Method 3
secondary optics that include telecentric lenses
Implementation Method 4
sharp-edged wedges to ensure uniform illumination
Implementation Method 5
multiple small multi-junction photovoltaic cells
Data Source
AI summary
An apparatus is disclosed for generation of electricity using sunlight focused onto multi junction photovoltaic cells having high conversion efficiency. The apparatus includes a large paraboloidal mirror of back-silvered glass, turned to the sun throughout the day, so as to provide an intense focus. Multiple photovoltaic cells are provided at the focus. The optics are configured to distribute sunlight without significant loss into separate regions matched to the photovoltaic cell size. A secondary optical system takes strongly focused sunlight near the focus of a single paraboloidal mirror and distributes it equally between the cells, and regions of equally concentrated sunlight are matched to cell size and are substantially co-planar, so that the cells may be grouped on flat circuit cards.