Improved Heliostat Array for Roof Top Solar Power

University of California System: University of California, Berkeley
posted on 11/06/2009

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Solar power towers (also known as ‘central tower’ power plants) use arrays of flat, movable mirrors, called heliostats, to focus sunlight on a collector located in the tower to produce electricity. Commercial interests in solar towers and their heliostat arrays has recently increased. In contrast, roof-top solar installations typically use flat, rigid solar cells to convert sunlight into electricity. However, these solar cells are relatively heavy and thick, and consequently they are relatively expensive to manufacture, ship and mount. To address the weaknesses of solar cells by leveraging the growing interest in heliostats, researchers at UC Berkeley have developed a design and fabrication method for low cost, lightweight heliostat arrays that can easily be mounted on roof-tops. Furthermore, these novel heliostat arrays are efficient — for example, at 15% system efficiency, an unshaded house in the Bay Area with 100 square meters of these arrays could produce 10,000 kW-hr per year. 

Roof mounted, solar power generation

• Low cost
• Low profile (reducing wind loading)
• Low weight (for easy roof mounting)
• Low maintenanace (no lubrication required)
• Can be integrated into roof shingles
• Can be manufactured from recycled materials (e.g. milk jugs)