Russ Daniel

Carl Nystrom wrote:A pelton wheel is an impulse turbine, which by design calls for a high velocity jet of water. With less than 3 feet of head, it would barely spin. Pelton wheels are probably the most commonly available off-the-shelf designs, because they meet the design criteria that is most likely for a micro-hydro setup: low flow and high head.

Your site has the opposite - low head but massive flow! Seriously, even if it is half as much water as you estimate, it is still an incredible resource. The bad news is that it is so large that you are probably not going to find a plug and play solution. What you ideally would have is a reaction turbine, which would be submerged in the water flow - look up a Kaplan turbine to get an idea. You will notice that the pictures that come up tend to be massive... You might also look at a cross-flow turbine (which is what I use). You could try and build something, but it would likely be a pretty challenging project.

What does the outflow look like? You say the pipe buried, so does it just come out of the ground right at the stream bank? If it were me, I think I would start with something very simple. I would think about building some sort of simple tail-race, and just putting a little undershot or breastshot water wheel in there. It would not be the most efficient, perhaps, but it would be super cheap compared to the other options. Even a wooden wheel turning a permanent magnet motor with some v-belts would work.

How far is the site from where your batteries would be? 12v is terrible from a transmission standpoint, so unless the pipe is like tens of feet from the house, you will probably want to up the voltage. This is not hard to do, and there are inexpensive controllers that will let you input up to 100 volts and step it down to whatever your battery voltage is.

Carl, every measurement and subsequent bit of math that I’ve been able to scratch out of this, indicates somewhere between 3 & 4 kw of potential.
I don’t understand enough about fluid dynamics to calculate or frankly estimate what I’d lose through the pipe, but if I’m able to de
n and implement a breast shot waterwheel, I believe I’ll be able to squeeze 1.5kw out of my stream. If I meet the right engineer, I believe I may possibly be able to achieve a little more, maybe up to 2kw. That, in conjunction with a few decent solar panels, a moderate Ann JJ mm battery bank, a charge controller and inverter.. and
I hope we’ll be golden! My next challenges will be design wheel.

Paul Fookes wrote:Try a pelton wheel.  You can buy one or make it,  The voltage is dependent on what you want.  The higher the voltage, the further the current will travel with smaller % losses.  Just remember that ultra low voltage (usually DC) and low voltage (usually AC) wires are different in that ultra low voltage has more wires of a smaller diameter but more in a bundle so it is thicker.  Depending on the distance, you can use a ground negative system where only the positive (or active) wire is run and you use ground spikes for the negative (or neutral) run.

Good advice, except there is zero probability of a peloton wheel working with only a 2.7’ drop. Thanks for your reply though.

Nancy Reading wrote:I was going to suggest an archimedes screw turbine, see renewables first website.  But it looks like you need at least 1m to have a reasonable system, so I'm not sure if it would scale down further.
You may need to be more creative.  I haven't searched the Permies forum itself though, so someone here may already have installed a small scheme like yours.  What sort of turbine was there perviously?

I wish that I knew the answer to that. The entire system, except for the inlet and underground pipe, has been vandalized and stolen. The fact that the surviving charge controller and battery bank is 12 volt tells me that perhaps they had not figured it out either.

Hi everyone! We purchased a distressed property in Montana that contains some of the infrastructure  of a previously functioning hydro system. It was an old 12 volt system from the mid-90’s.  I’d like very much redesign this system and make it functional again.

Here’s what I have to work with, and it is challenging: A high flow year around creek, with a diversion channel dumping into a 2’ diameter buried corrugated pipe running approximately 900’ with only 2.7’ of drop/head. The pipe is continuously full. My calculations (I’m not 100% sure of my math) indicate that is over 8000gpm and at 100% efficiency, should generate over 2kw continuously.  I cannot find an off the shelf resource that would fit my site and would like expert, or at least well reasoned opinion, on my math for what is possible. Also can anyone out there guide me to good resources for suppliers of low head solutions and advice?