How the Humble Sunflower Holds the Key to More Efficient Solar Power

Published on CleanTechnica, January 2012

Regular readers are well aware of concentrating solar power (CSP), the growing technology which uses the sun’s energy to heat fluid (not unlike a steam engine) rather than using photovoltaic cells to convert it directly to electricity. If you’re not up to speed, we recently published a quick primer on CSP and why it could be vital to tomorrow’s energy mix.

But every CSP installation requires hundreds of mirrors to catch the sun’s rays and direct them towards the central tower, where the fluid is stored. The problem is, those mirrors take up a lot of space. That’s why, so far, the majority of CSP installations have been in fairly out-of-town desert locations.

But, now, a team of researchers at MIT have come up with a way of packing the mirrors — known as heliostats — in more tightly, while still efficiently directing the sun’s rays to the central tower. And the solution takes its inspiration from a very appropriate source in nature — the sunflower.

At most CSP sites, the heliostats — typically several hundred of them, each the size of half a tennis court — are arranged in concentric circles. As MIT explains, “The spacing between mirrors is similar to the seats in a movie theater, staggered so that every other row is aligned. However, this pattern results in higher-than-necessary shadowing and blocking throughout the day, reducing the reflection of light from mirrors to the tower.” Good sunlight wasted, in other words.

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