An Astronomer’s Solution to Global Warming: The Technology Developed for Telescopes, It Turns Out, Can Harness Solar Power
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Roger Angel is an astronomer whose innovative designs for telescope mirrors have radically transformed the way we see the stars and galaxies. He developed lightweight, honeycombed mirrors for the world’s largest and most powerful telescopes, including the Large Binocular Telescope on Mount Graham in Arizona and the Giant Magellan Telescope currently under construction in Chile. He is a Regents Professor and head of the Steward Observatory Mirror Lab at the University of Arizona (UA), and a MacArthur “genius grant” Fellow. In 2010 he won the prestigious Kavli Prize for Astrophysics,. But lately he’s been thinking more about life on our own planet.
“I had been worrying about global warming,” Angel says, and he had begun contemplating solutions as audacious (and ultimately cost-prohibitive) as placing giant sun shades in space to cool the planet. But when his wife asked him, “Can’t you do something about global warming?” he got serious and began envisioning how his telescope mirrors could be used to generate clean energy. Now Angel has fashioned a system that utilizes mirrors with tiny solar cells to harness light and generate electricity, a system that has the potential to be more cost-effective than anything else on the market.
Trying to harness the power of the sun is nothing new; many companies and inventors have been analyzing the problem of how to most effectively collect, convert and use solar energy for decades. The technology of photovoltaic (PV) cells that capture the sun’s rays has improved over time, but there are still a few sticky pieces to the puzzle of producing solar electricity. Some of those issues include the amount of heat generated by existing techniques, the space needed for the solar cells and cost.
Angel is tackling a few of these problems with his new system. “It’s a complete self-contained unit that turns the light into energy and rejects the heat,” he says. Scattered around his Tucson lab are tools, scraps of metal, bits of PV cells and other pieces of the contraption. Put together, it will consist of several square mirrors attached to a large, lightweight steel frame that looks like a jungle gym. Each mirror reflects light into its own cube-shaped power conversion unit (PCU) installed above its center. The PCU is a small box with a fused silica ball on the end that faces the mirror. As the light from the sun hits the mirror, the mirror’s parabolic shape focuses the beam directly into the ball, which in turn focuses the light onto a curved matrix of 36 tiny PV cells. The cells are what convert the light into electricity.