Hasta La Gadget!

Just what were you doing at 13 years old?

[UPDATE Aug 22 2011. All may not be as it seems. According to Gadget Lab reader and grown-up Patrick Theiner, Dwyer made several schoolboy errors when making his experiments. An article debunking the experiment and results appears on the UVdiv blog. Apparently Dwyer was measuring the open voltage on the circuit, which “is practically independent of power output,” and stays all but constant regardless of light falling on the cells.

This post also says that the theory is flawed, and that pointing the panels in different directions, most of which aren’t at the optimal angle to the incoming light, will yield less power than a flat panel. You can read the full math here. (Oddly, the post has itself disappeared, but you can read Google’s cache.]

13-year-old Aiden Dwyer has managed to do something that grown-up scientists haven’t. He has wrung up to 50% extra electricity from regular solar cells. How? Brains, trees, and a dash of math geekery.

Dwyer was hiking in the Catskill mountains when he started to see patterns in the mess of branches. Where you or I might see chaos, Dwyer saw spirals. Measuring the patterns, he found that the spiral forms of the leaves and branches were placed according to fractions that obey the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21, 34…).

Trees and plants are pretty good at capturing sunlight, right? So Dwyer took these numbers and built his own tree, only instead of leaves the tree has solar cells:

I designed and built my own test model, copying the Fibonacci pattern of an oak tree. I studied my results with the compass tool and figured out the branch angles. The pattern was about 137 degrees and the Fibonacci sequence was 2/5. Then I built a model using this pattern from PVC tubing.

In place of leaves, I used PV solar panels hooked up in series that produced up to 1/2 volt, so the peak output of the model was 5 volts. The entire design copied the pattern of an oak tree as closely as possible.

As a control, he also built a regular flat-panel solar array, familiar to eco-hippies everywhere (but mostly Californian eco-hippies).

Dwyer tested the two arrays side-by-side from October to December. Under the more plentiful October sun, his tree “made 20% more electricity and collected 2 1/2 more hours of sunlight during the day.” But in December, when light is scarce, “the tree design made 50% more electricity, and the collection time of sunlight was up to 50% longer.”

Not bad, right? And Dwyer isn’t done yet. Currently he’s investigating the different Fibonacci patterns on different trees to find out which is most efficient. As it is, his invention tracks the Sun better, produces more power and takes up less space than a traditional flat cell array. Suck on that, adult scientists!

The Secret of the Fibonacci Sequence in Trees [American Museum of Natural History via the Giz]