Safe, Simple, Cheap: New Solar Tracking Technology a fit for Third World
September 19, 2011
Eden Full, a 19-year-old Princeton University mechanical engineering student has developed a non-toxic, cheap, recyclable device made out of metal and bamboo that allows solar panels to follow or track the Sun without the use of an electric motor. This does two things: 1) it boosts the output of the solar panels by about 40% (huge) and 2) it does so using a much cheaper and simpler method than traditional trackers commonly used in commercial projects (her technology costs $10, a lot less than the typical $600 solar tracker).
The concept is simple, really. Steel expands at a different rate than aluminum when exposed to heat. Full has combined steel and aluminum into bimetallic strips, which are attached to an axel running across the back of a solar panel.
She won’t go into too much detail until her patent on the invention is published, but when the sun hits the strips the resulting heat causes the aluminum part of the strip to expand more than the steel part. This causes bending and twisting of the strips.
Full has figured out a way to configure and control her system so that the bending strips keep her panels, for the most part, directly aimed at the sun.
Inspired by a deeply felt love of the natural world, and an awareness of the terrible costs of fossil fuel energy, Eden was inspired at an early age to take on renewable energy as a mission.
My parents instilled a sense of responsibility towards the environment when I was younger and I carried this value with me throughout my life. I had the opportunity to travel to the Canadian Arctic two years ago where I witnessed the depressing lack of sea ice as a result of climate change, which made it hard for animals to find food and land. On a Zodiac boat ride, I had a chance to get within five metres of a polar bear that was so desperately hungry he didn’t even bother to turn away from us. This was an emotional moment for me when I realised that I had a chance to help prevent this problem from getting worse. I would have to help with the reduction of CO2 emissions.
Climate Denial Crock of the Week 
September 19, 2011 at 3:05 pm
I’m torn between excitement and skepticism about this. Bimetallic strip stuff has been around for generations, and its mechanics are well-understood. Basically, the bimetallic strip curls as it heats up. This curling doesn’t have a lot of strength behind it and it doesn’t curl through a big arc. It might be that she is relying on special alloys that make it possible. There’s also a big problem that the system will respond differently at different base temperatures (on cooler days, its motion will be less than on warmer days). If she’s clever, she has a double-strip system in which one strip handles base temperature while the other handles “solar temperature”. And she probably has some sort of “French curve” scheme that transforms the geometry of the bimetallic strip expansion into something more closely tied to the motion of the sun. In any event, the thing can only yield an approximation of the correct position, which is probably good enough to get a worthwhile performance improvement.
September 19, 2011 at 5:01 pm
Agreed. Solar panels live outdoors, in the wind and rain. The tracking system has to be robust enough to withstand squalls. That sounds like a significant challenge for a $10 device. Otherwise, a simple mechanical clockwork mechanism would work.
September 20, 2011 at 1:17 am
These are the type of stories that really make an engineer feel good about the world. Imagine if we put our nation’s spending priorities on energy, the education and talent are certainly available.
November 9, 2011 at 8:01 pm
I sincerely wish Ms. Full much success but my gut feeling is that this $10 will not be able to withstand the rigorous weather conditions to which solar trackers are oftentimes subjected; thereby proving the dichotomy of theory and practice a/k/a the “real world.”