micro hydro, big river

my grandma's place is on a fairly large river.  it's about fifty yards wide and ten feet deep.  so there's a lot of volume, but it's very slow.  probably only drops a couple of inches in the 150 yards of river the property sits on.

any ideas for energy generation or water pumping?

No direct answer Tel, but I saw a video on youtube about a generator and runs on water being shot into it by a pump.  The generator makes enough energy to power the pump that runs it, you just need a car battery to jump start the whole she-bang.  The was under a search I did for zero-energy. 

Without a drop - something like this generator sounds like a possible solution for your situation.

Sorry I don't have a better answer.

A couple of possibilities.  Piezoelectric generation such as here http://tinyurl.com/y8k7unq. ; and undershot water wheel with a lot of gearing if setting one up doesn't violate state regulations.

By the way Jamie, what you describe is a perpetual motion machine and cannot work, a water jet created by a pump cannot make enough energy to keep the pump running.   An additional energy source would be needed.

Hum . . . that is how they presented it working.  And that was why it was listed under zero-energy, claiming it produced enough energy to run it's self. 

I don't doubt what your saying, as it seemed to good to be true and I just don't know for sure either way.

mekennedy1313 wrote:
A couple of possibilities.  Piezoelectric generation such as here http://tinyurl.com/y8k7unq.  and undershot water wheel with a lot of gearing if setting one up doesn't violate state regulations.

I read your piezoelectric link.  seems like that would work best in a more turbulent stream.

the undershot water wheel might work.  I could probably put one in right along the river bank without any hullabaloo, but the current's also the slowest there.  definitely not an option out in the middle.  state regulations... I think this is probably in the realm of federal regulations, which probably won't help my cause.

I should also mention that the water level fluctuates pretty dramatically seasonally.  there's easily a difference of ten feet most years, so it should probably be removable.

would a ram pump work if I used large enough diameter pipe?

WRT ram pumps no way to know without knowing the speed of the river.

so... what's the minimum?

not sure but rim speed is normally about 65% of the water speed.

... check out http://www.wvu.edu/~exten/infores/pubs/ageng/epp13.pdf

Ultimately, the power generation formula will tell you whether or not a particular 'location' is a reasonable candidate for micro-hydro generation

KW (generated ) = 0.0846 * available 'head' ( in feet ) * 'captured' flow ( in cubic ft per sec ) * mechanical efficiency of water to generator setup ( typically 50% )

in your particular location with very little 'head', it is probably critical to determine precisely how much elevation change exists between the upstream and downstream property boundaries.  This is really easy to do with excellent accuracy if you can simply get ahold of 450 ft of garden hose.  If the available 'head' is truly only a few inches, though, from a practical standpoint you don't have enough 'raw material' to work with.


(snip)Hydro electric power is the most reliable and cost effective small-scale renewable energy source available. A small hydro system utilizes a turbine, alternator, water jets aimed at the turbine and a control circuit. Other required components are a battery storage bank, regulator and enough water line to get the water to the turbine. Hydro systems, unlike solar components, do require some maintenance. To take advantage of hydro power your water source must provide both volume and pressure (otherwise known as head). If your creek or stream can deliver more than 5 gallons per minute then you have enough flow volume. Pressure, or head, is the height the water falls vertically. A standard microhydro system needs at least 10 feet of head in order to provide usable amounts of power. (snip)

from http://www.theotherpowercompany.ca/Hydro.html

undershot wheels gain no advantage from head, just volume and speed.  thats why although the simplest they are also the least efficient.

^^^ true about undershot water wheels ... where the available 'head' is limited to the naturally occurring water height build-up between the upstream and downstream side of the wheel.  As you point out, this naturally occurring water height build-up is a huge function of the surface velocity of the river water.   

Again this is easily tested by simply walking out into the river while carrying a 4 x 8 sheet of anything held perpendicular to the river bank.  If you and the 4 x 8 sheet both start heading for the next county, then an undershot water wheel might offer good promise.  If on the other hand if all that happens is that a little bit of river water flows around the ends of the sheet then an undershot wheel won't even be able to turn itself ( due to bearing friction ) let alone turn a generator.

I also just picked up on Tel's statement that the river water level varies by 10ft from wet to dry season, which implies that the river water level varies by several inches from day to day based on recent rainfall etc. .  This alone would render an undershot wheel installation impractical. 

water level change doesn't have to make an undershot wheel impractical.  Some of the earliest actually were in a structure that floated on the surface of the water.  The connecting belt had tensioners to give out and take up slack sort of like the spring loaded rear derailer on a bike.

i wonder if you could use the depth of the river as head for a ram pump.  inlet at the top of the river (floating mount), pump at the bottom.

what is the possibility of building a mill wheel in the river?

you can build a nice big one in the middle of the river and step gearing till it spins at generation speeds. used to be the norm for lathe shops not to long ago.

Ernie wrote:
what is the possibility of building a mill wheel in the river?

you can build a nice big one in the middle of the river and step gearing till it spins at generation speeds. used to be the norm for lathe shops not to long ago.

chances of building anything in the middle of the river are pretty slim.  it's a popular river to fish in so there's a lot of motor boat traffic.  it's also about 150 feet wide.

if I build anything it's going to have to be near the bank.  maybe twenty feet out would be the very maximum.

this is the sort of river with docks on it.  my grandma had a dock until the last bad flood sixteen years ago blew it out.  the neighbors on either side both have docks.  slow.

maybe I'm dreaming about getting any power from it.  but there's so much water, there's got to be some way.

look at the history of the river in your area, have their ever been water wheels? If no then I bet that isn't feasible.  Leaves the piezoelectric option as the only one I could see possible.

I'm guessing that there have been water wheels, but prior to the existence the three dams up river.  there's still a functional water-powered grist mill on a tributary, but that's a whole other situation.  involves a sluice maybe half a mile long.

would this work?  is there a place to affix the tether?

www.hydro-electric-barrel.com

that looks very promising.  the pylons and swinging arm would have to be fairly tall to accommodate the substantial changes in water level, but I think something like that could work.

I could probably build it in such a way that it could be removed during exceptionally high water when there's a lot of debris cruising down the river.  looks like it could be built fairly cheaply, too.  a plastic 55-gallon drum for the barrel, for instance.  may have to give it a shot.

thanks for the link.

Adding my question to an old post. That HEB barrel idea looks promising! But it's only in development. Does anyone have links to things that are available and work?

We're on a plateau about 90 feet (30m +) above and next to a strongly rushing river. In this desert we need to irrigate, and our gravity source is not quite sufficient. There's a lot of power in the river water -- scary to swim.

We have about 3 or 4 foot drop of river height along the length of our land, so one suggestion was a canal or big pipe and then a ram pump utilizing that small head. But all along the river side is a 90 foot sandy and stony sheer cliff right up to the edge of the plateau, so a canal would probably often get dumped over, and a pipe would be prohibitively expensive.

90 feet is too high for an archimedes screw based system.

Any other suggestions for currently available ways to pump water up 90 feet, from a strong river with a low head? Oh -- the river goes up and down by several feet.

Rebecca Norman wrote:
We have about 3 or 4 foot drop of river height along the length of our land, so one suggestion was a canal or big pipe and then a ram pump utilizing that small head. But all along the river side is a 90 foot sandy and stony sheer cliff right up to the edge of the plateau, so a canal would probably often get dumped over, and a pipe would be prohibitively expensive.

I'm doing some research on available hydro projects for my own land. Looking at that picture, I would say your land and river is ideal for a waterwheel structure. Look nice too imho.

Looking again at your picture and the area with the large drop, right of the buildings. Looks somewhat like my own site, lot's more water though lol. To my eye, that area looks to fall more than 4ft ? It might just be me... If you have access to the opposite side flood plain, which is very like mine. It looks ideal for a vortex model. I would have to see close ups, but yeah from that angle it sure does look similar and its vortex atm for me. Of course, if I'm seeing the picture wrong or you have no way to access the opposite bank. I still say waterwheel, at the same drop.

That is only my opinion though, I don't know any of the finer details.

Thanks. Do you have any links to info about modern water wheels?

The sandy cliff from the plateau down to the river is 90 feet. The downward flow of the river from one end along the edge of our campus is 3 or 4 feet -- well actually we haven't measured it properly but that's what we estimate.

About the flood plain opposite... We did get a lease on it when we were first at this site, and we went and planted the trees you see, but hardly ever went back because it was too dangerous on a canoe, and too long to drive to the bridge and back. So when the 10-year lease was up we let it go.

Sorry for the delay in my reply Rebecca, very busy atm.

Yes the sandy cliff is a real problem, although, if you have the large stones at the base that I think I can see in the picture ? This area would be my choice to build any structure that would hold a waterwheel. As I say, I cant see or don't know all the problems that may arise, I'm just going by my own instincts and the one picture. The 90ft drop is only a problem if a hired crane cannot drop the heaviest items down safely. It's a pity about the flood plain being so inaccessible for you, it looks ideal. The rest, too my mind, is enough resources and man hours to build a simple riverside structure. You can see many examples of simple waterwheel construction all over Europe. Im sure some of these designs would fit your requirements. If you have enough water going under the wheel, it should gear nicely into a generator. To me, any design has to be robust and have a long life.

Thanks!

tel jetson wrote:my grandma's place is on a fairly large river.  it's about fifty yards wide and ten feet deep.  so there's a lot of volume, but it's very slow.  probably only drops a couple of inches in the 150 yards of river the property sits on.

any ideas for energy generation or water pumping?

I'm kinda late answering this interesting idea/problem.....
Reduce the width to 1 yard with a dam and you get ~50x more water pressure/speed.

Any potential to build a small mill race off the main flow?

Are you hoping for electricity or irrigation water?

With a fairly small drop and some excavation work you could set up a trompe/pulser pump. One shot deal to set up, with no moving parts. They only need a few inches of drop to extract some power.

Thank you, now I'm googling "trompe/pulser pump"!

Hello tel jetson,

From what you describe you have huge volume but little flow. I live in Australia and dams on rivers are a no no, is that the same where you are. If so you are looking at a submersible system. Very easy to home build and cheap. Do have an idea of what voltage and wattage you want, or are you just seeing what could be had.

Regards

Peter