Nuts and Volts - February 2011

by Bryan Bergeron, Editor by Bryan Bergeron, Editor

DEVELOPING PERSPECTIVES

Harvesting Power

The increased awareness of climate change and focus on renewable resources has been a boon to the green industry. Fully electric cars — although still expensive and impractical for most of us — are in fashion. Then, there are the wind farms springing up around the US, and talk of wave-powered generators along the east coast. Of course, dams have long been a source of mechanical and electrical power.

Although you may not be able to afford a $100K Tesla Roadster, there are affordable electronic devices that harvest energy from minute vibrations, sunlight, and even water. This last category of technology caught my attention recently as I walked through my local hardware store. Of course, I’m talking about the water-powered LED showerheads and faucet attachments that change color to indicate water temperature. These relatively inexpensive

units (starting at $7 on Amazon) power LEDs to indicate cold (blue), warm (green), and hot (red) water. Above a certain temperature, some units also blink red to indicate dangerously hot water.

My teardown of a $12 unit revealed a few LEDs, a thermistor, and — most significantly — a miniature turbine generator. While no match for Hoover Dam, the mainly plastic turbine manages to power a handful of high-output LEDs by extracting energy from the flowing water. The quality of the inexpensive, Chinese-manufactured device isn’t impressive, but it is on the market, it’s affordable, and it works. That’s more than can be said for a lot of green technologies that are ‘not quite there yet’ economically or technologically. Sidewalks that capture the energy imparted by pedestrians have yet to make it to my community.

My first thought on seeing the miniature water turbine was to identify other practical applications for the device. Could these turbines be wired in parallel and be used to generate power from a river or stream? Or, be placed in gutters as indicators that they’re not clogged. Or, used with a water cooler tap to heat or cool water with a Seebeck device — another technology that can be used to reclaim otherwise wasted energy.

The point is, there’s a lot of wasted energy in our everyday environment and experimenting with methods of harvesting that energy isn’t limited to corporations with deep pockets and teams of researchers. Where can you start? As I’ve noted in previous editorials, economically, it probably makes sense to start with a teardown of a mass-produced product. If you can afford it, you can try your hand at official product evaluation kits. The advantage of quality evaluation kits is that they provide the documentation and electronic infrastructure to get you up and running in hours instead of days.

Whether it’s a turbine generator or one of the new, higher-efficiency solar panels, get your hands on the technology and put your imagination to work. That doesn’t mean going it alone in your basement, however. Use the wealth of information in the US and international patent databases, and keep track of new product announcements on the high-tech websites. You can also form a club of like-minded experimenters. Thanks to the Internet, forming a virtual club or special interest group is only a few keystrokes away. Of course, the old-fashioned, face-to-face gatherings are hard to beat, if you have the time and happen to live near like-minded experimenters.