Currently at my property I have a small brook that has a small waterfall with a pool at the base of the falls. From this pool part of the water is diverted through a pipe to a dug pond and then via an outlet pipe its diverted back to the brook a bit farther down so there is constant flow through the pond. If I wanted to harness the outlet pipe for a small hydro generator, most likely with a pelton wheel, is the head calulated as the distance from the base of the waterfall where the inlet to the pond is or just from the start of the outlet pipe from the pond to where it reenters the brook. The outlet pipe is submerged most of the time so its almost like the pond is one giant bulge in a continuous pipe from the inlet at the waterfall pool to the outlet at the pond.
Calculate the head from the surface of the pond. Any water that's not in a pipe is at atmospheric pressure (0 PSI) at its surface. If you had water in a pipe from the waterfall, that didn't surface at the pond, that would be a different story. What's your head and flow rate? Year round?
Gravity is a harsh mistress. But this tiny ad is pretty easy to deal with:
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