Today I found another DIY project for generating alternative energy, by using the wind. It is a Vertical Axis Wind Turbine (VAWT), and it works by the same principle those huge wind turbines do, but they are much more easy and less expensive to build.
Here’s a brief description of the VAWT’s functioning and manufacturing instructions. That’s the basic info, you can get more from the manufacturer’s website (make sure you come back after you visit them).
The vertical axis wind turbine‘s alternator has two 12 inch diameter rotors that each have 12 neodymium disk magnets measuring 1.47 inche in diameter and .6 inches thick. Between the rotors is the stator consisting of 9 coils of awg #20 wire, 200 turns each. The coils are arranged to produce 3-phase ac. Each phase has 3 coils wired in series. There are 3 full wave bridge rectifiers, one for each phase. Each is isolated from the other. All three rectified dc outputs are wired together in parallel and the dc is sent via cable to the battery bank.
The stator is made by sandwiching the coils between two pieces of epoxy fiber glass board, the kind used in the manufacture of printed circuit boards. The top and bottom sheets, each 1/16 inch thick, are held together with bolts. They have reinforcing ribs added for stiffness. Power is brought out by means of stainless steel machine screws.
If you’d like to build one yourself, you must know it can theoretically produce 316W, by the formula:
“Watts = Conversion constant * Betz limit * efficiency * area in sq. m * wind^3
In a perfectly efficient turbine,
Watts = .05472 * 59% * 100% * 4.46 * 13^3 =316 watts”
Of course, things are far from perfect, the guys that made this said they got 70W out of it. That’s pretty good! Make a few similar vertical axis wind turbines, put them on your block and you’ll never pay for electricity again! (more or less – depending on your consumption habits). Anyway, if you live in an area with high winds, these devices can charge some 12V car batteries so they power your home for the morning and evening, when you get back from work. During the night and the day, they accumulate energy from the wind turbine. The only serious “permanent” consumer would be your fridge.