Background
The generation of electricity from sunlight is currently not cost-effective in many situations because of the inherent limitations of photovoltic (PV) cells and typical lighting conditions. Increased PV cell efficiencies and minimizing the costly materials and fabrication techniques will reduce costs.
One promising way to accomplish this is with concentrator PV (CPV) systems, where an inexpensive optical element (usually made of glass) covering a large sun-lit area is used to greatly concentrate the light onto a small PV cell. Higher light intensities enable higher efficiencies in converting sunlight to electricity while greatly reducing the size of the required PV cell. Optimization of solar concentrator design depends on maximizing light concentration and optical efficiency while enabling facile alignment of the system with the sun.
Description
A University of California, Merced researcher has invented a CPV design that features higher light concentrations, coupled with high efficiency and a generous acceptance angle for easy solar tracking. In this CPV design, a glass element with two aspherical surfaces (a small portion of one surface is metallized) achieves high light concentrations by refracting the incident light and generating a pair of internal reflections. The emergent light beam yields an aplanatic image focused on a PV cell mounted on one of the surfaces.
Applications
This invention may become a preferred design for CPV systems, helping make CPV become more competitive as compared to fixed panel arrays for solar electricity generation. The concentrator optical element may also be used in reverse to provide a highly collimated light beam from light emitting diodes.
Advantages
This solar concentrator design offers a number of potential benefits over previous concentrator technologies, including:
• higher light concentration (1,200x),
• high optical efficiency (81% on axis),
• large acceptance angle (±3° at 90% intensity),and
• compact size (~20:1 ratio of optical element thickness to PV cell width).
Patent Status
Patent Pending
Inventor
Roland Winston
