Solar PV Generator with Fly's Eye Receiver
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solar electrical power generation systems using large dish reflectors to power multijunction photovoltaic cells face inefficiencies due to complex and costly designs, including uneven sunlight distribution, high material costs, and reduced conversion efficiency from chromatic aberration and reflection losses, as well as the complexity and expense of dual-axis trackers.
Innovation Solution
A two-stage concentration system using a large concave reflector and a fly's eye lens array to concentrate sunlight onto small, highly efficient multijunction PV cells, with a field lens forming a stable pupil image for the first stage and a fly's eye lens array for the second stage, minimizing losses and allowing for efficient series connection and reduced heat flux, while a dual-axis tracker design uses a rigid triangular spaceframe to minimize material and installation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single large focusing dish reflector is used to concentrate sunlight onto a small array of multijunction PV cells, then the conversion efficiency increases and cell cost per unit power decreases, but the distribution of concentrated sunlight becomes uneven among cells and light is lost in gaps between cells
Solution Approach 1:
The patent divides the concentrated sunlight distribution into discrete segments by using individual optical elements (lenses or mirrors) for each PV cell. Each optical element focuses light independently onto its associated cell, ensuring uniform distribution and eliminating light loss in gaps between cells. This segmentation approach replaces the single large focus with multiple smaller, controlled focus points.
Solution Approach 2:
The patent introduces intermediary optical elements (lenses or mirrors) between the dish reflector and the PV cells to mediate the light distribution. These intermediaries actively control and redirect the concentrated sunlight to ensure each cell receives uniform illumination, preventing light loss in the gaps between cells while maintaining high conversion efficiency.
2Power
If Fresnel lenses are used as focusing optics, then concentration is achieved, but light is lost by scattering and chromatic aberration reduces conversion efficiency
Solution Approach 1:
The patent employs conventional PV cells with tracking mechanisms rather than expensive multijunction cells, accepting that the system requires movement and adjustment to maintain optimal positioning. This approach trades off the use of highly efficient but static multijunction cells for more economical cells that can be paired with dynamic tracking, thereby reducing overall system cost while maintaining productivity.
Solution Approach 2:
The patent changes the operational parameters by using single-junction PV cells that respond to broader spectral ranges and pairing them with tracking systems that adjust positioning parameters. This allows the system to maintain high conversion efficiency through dynamic adaptation rather than relying on the static spectral optimization of multijunction cells, thereby avoiding chromatic aberration issues.
3Productivity
If many small focusing optical systems are assembled into a module with individual optics for each cell, then high conversion efficiency is achieved, but the assemblies become large, heavy and complex driving up manufacturing and transportation costs
Solution Approach 1:
The patent merges the dish reflector into a single large structure that serves all PV cells simultaneously, rather than using separate small optics for each cell. This consolidation reduces the number of optical components, simplifies the overall assembly, and decreases weight and complexity while maintaining the ability to concentrate sunlight effectively onto multiple cells through a unified optical path.
4Area of stationary object
If cells are packaged close together to form a dense array, then a much smaller cell area is needed for highly concentrated sunlight, but light is lost in gaps between cells and at light-insensitive electrical busbars
Solution Approach 1:
The patent segments the optical system so that each PV cell has its own dedicated optical element (lens or mirror). This segmentation ensures that concentrated sunlight is delivered directly to each cell without spilling into gaps or hitting inactive busbar areas, eliminating light loss while allowing cells to be closely packed to minimize the overall array area.
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 system achieves higher solar conversion efficiency with lower production costs by maintaining optical etendue and minimizing reflection losses, facilitating electrical wiring and thermal management, and providing a cost-effective dual-axis tracker design for accurate sun tracking.
Implementation Method 1
a large concave reflector and a fly's eye lens array to concentrate sunlight
Implementation Method 2
a field lens forming a stable pupil image for the first stage
Implementation Method 3
a fly's eye lens array for the second stage
Implementation Method 4
multijunction photovoltaic cells
Data Source
AI summary
An apparatus for generating electricity from solar energy has a large dish reflector with a fly's eye receiver positioned near the focus of the dish reflector, held by a dual axis tracking structure. The fly's eye receiver includes a field lens that concentrates sunlight into an image of the dish reflector, a two-dimensional fly's eye array of contiguous convex lenses extending across the dish image, and a photovoltaic cell behind each convex lens of the fly's eye array. Two imaging stages are provided. First, the dish reflector and the field lens concentrate the sunlight in the form of an image of the dish that is stabilized against pointing errors of the tracking mechanism. Second, the contiguous array of convex lenses divides the sunlight energy of the dish image into portions, one per convex lens, each portion being further concentrated by the respective convex lens onto a corresponding photovoltaic cell.