Tank as Penstock

[Carlon Swarey]

Hi y'all. Have a small stream on my place, I estimate 10-15 gpm and 20 or so feet of head. The elevation drop is over a long distance. I was wondering if it would eliminate friction loss if I would run the water into a tank and have a small spout at the bottom of it to run a turbine, versus the friction of 1000 feet of pipe. We have an excavating company and I occasionally have access to big free fuel tanks that we remove from defunct gas stations. I'm talking 8 feet in diameter and 16-20 feet long.What if I would set that tank upright so it is 20 feet tall and run water into the top, and then run a pipe out of the bottom of it directly into the turbine. Would I be improving myself any? Thanks

[Rob Beckers]

Hi Carlon,

I works (as you describe), but you're just moving "the problem".

Instead of limiting friction losses in the pipe so you have enough pressure at the turbine, you now move it to having to provide enough flow to keep the turbine going. That means ensuring at least the same flow rate into the tank as the turbine takes out the bottom. When you work the numbers I'd be surprised if you don't end up with the same pipe constraints.

-RoB-