Hydro Power 2

As expected, there is a lot of high-end theory involved with the design of Pelton Wheel hydro installations, and mine is only haphazardly poking at the arithmetic.

Had a look at the Wikipedia page on Pelton Wheels:

http://en.wikipedia.org/wiki/Pelton_wheel

...and learned that the velocity of the stream of water is best calculated to be twice the speed of the rim of the wheel. Since the speed of the runner is regulated by the output voltage of the generator, that is pretty much a constant in my installation. Varying the speed of the water entering the runner is probably more important than varying the flow.

Friday, I stopped by the hardware store to see what they had that I could use for changing the nozzle in the small plant that I built. They had a small brass "driveway washer nozzle" (high pressure fitting) and a plastic "sidewalk tunneling kit" that looked like I could cut it down and cobble something together. I bought them both.

The easiest change was to simply unscrew the nozzle I was using and screw on the small brass replacement. This new nozzle has a 5/32" hole instead of a 3/16" that the original had. Turning on the water produced .78 amps of current, or 11 watts, a 10% improvement. The water pressure at the nozzle ran at about 25 PSI, an improvement for the rest of the domestic supply.

At first, I was rather confused as to why a smaller orifice produced more power, but considering the stream velocity being the most significant factor, I guess this makes sense. Since Pelton runners work by diverting the flow of water, rather than simply by the impulse of the water hitting the runner cups, this makes sense. More water does not necessarily mean more power. Using the water entering the runner cup more efficiently does mean more power.

I did look around at the hardware store for Rain Bird nozzles, but they didn't carry them as replacement parts. I may have to try the bigger stores next time I go to the city.

I'm thinking that multiple small(er) nozzles would produce more power than one big one. Matching the water velocity to the runner speed will give best output for the least water used. If a smaller nozzle produces this desired speed, then several smaller nozzles would add additional power output. It's all about torque, not speed, the speed is fixed by the battery voltage. More nozzles = more torque = more power.

Now I have to figure out how to support the generator with a box or structure that allows me to mount and align four nozzles. Oy, more projects.