Water Wheel Blade Design

I think, as long as the blade is in the water it is still in the power stroke. The water will continue to push the blade until it exits the water. I believe the blades are angled to get the best effect at the right depth.

We used water wheels for a very long time and some really smart people designed them, other than materials improving on the design will be difficult.

Now, if you want to go a different direction, there has been a lot of research on sub surface designs. But the exact design for your river will depend on your situation. If you are next to a flat lazy river your undershot floating design will provide you energy. Perhaps a ducted fan might work if you put it underneath your float.

But my favorite design is if you have enough fall on the river between when it enters your property and when it exits. Someday when I buy a house in the countryside I want a small creek that I can dam up where it enters my property and run a pipe down to where it exits my property. Install a water turbine and viola water power.

Drew

I don't think there will be any advantage of having the blades fold back.

The axle of the flap will have to be below horizontal in the front before it will fall open again.

It may even be falling on top of the water surface causing it to float and prevented from entering the flow. The force of stream may actually fold it back close again.

Post some sketches of your idea then we can talk.

On my sketches the wheel will tend to run backward and pump the water upstream. (a perfect unintentional PMM)

I agree with the previous replies. Don't re-invent the wheel!
Adding complexity is just a problem creation exercise...which is surely the job of your wife?
Del

Hello All,

Thank you for a quick and informative reply.

Yes have to agree with you all.

In bed whilst pondering I did think of a submerged fan in a funnel as mentioned, thanks, guess i'm not so stupid after all.

Our river/creek is about 40ft wide and 10 deep running at around 3 knotts. What I really need to do is a lot of work so was trying to find the easy way out as usuall.

Our river floods frequently raising 15ft with huge trees at times so I need to dig an adjacent canal with gates so I can controll the flow and get my 10ft head of water over the 400ft required canal and put in low head generator that is made in Vietnam, costs 2000 usd and produces 24 kw of 110/240 volts.

Many thanks again

Quentin

Belize

If you have 400ft of this creek, you don't exactly need to make the canal unless you really want to make the 24 kw.

Instead of a canal, just run a section of pipe from a small side slip. The small side slip could be protected from flood debris with concrete. The pipe will be flooded and transfer your 10ft of head to a small turbine or impeller at the bottom. If you wanted to go a bit bigger you could use large storm drain pipe for greater flow, and a series of turbines/impellers on a manifold.

My plan was to use something like the impeller from a jet-ski. Use pulleys or gears to turn a generator and there you go.

Drew

Drew

low head generator is made in Vietnam, costs $2000 usd , produces 24 kw of 110/240 volts.

Please provide link to this product or dealer in North America. Sound like what I have been looking for.

If you do a floating wheel ( undershot) take a look at a feathering wheel. http://www.lulu.com/content/paperback-book/original-paddle-wheel-technology/1948578

This increases efficiency by 12 to 20 %.

But if you have 10 ' of head available, go to an overshot wheel as this will give more power than an undershot heel. The difference being that in an undershot wheel, the water can only act upon the surface area of the blades that are in the water , while in an overshot wheel the water can act upon the blades for 1/2 the diameter of the wheel.

If you don't get much cold weather an overshot wheel is much better looking than a small turbine hidden away. kind of nice to see the wheel turning.

Look for a book named "Cloudburst", not sure if 1 or 2, there are plans for different types of water wheels.

Vic

Locally we have a special problem. The stream is salmon habitat and government inspectors are really vigilant concerning anything that impinges on the water and any migrating fish in it. There is nearly zero head, maybe 12" drop in one quarter mile at point of acess. But during spring run off water speed is nearly 7 knots and even at low water, flow rate is 2 knots. You may wonder at the apparent contradiction of no head but extremely fast water. The drop dow from the creek to the actual river is considerable and tends to pull water along.

Water levels change by many feet from spring to fall so a floating wheel is really the only practical way to extract any energy. zero damming is permitted nor is a diversion canal since it may muddy up the water flow with silt. reek depth is barey 12" at lw waterbut is 7 feet at high water.

You don't have enough drop to do Run of River Hydro so how about this. Have a sling pump in the river (http://www.animatedsoftware.com/pumpglos/gl_sling.htm) to give you the flow you need for Run of River Hydro. No dam required.

This sling pump appears to require a greater depth of water namely the full diameter of the prop. By comparison an undershot wheel would only need a few inches of immersion or maybe half as much as the fully immersed prop. Obviously I'm missing something here. Perhaps its a question pf semantics. The sling pump is placed 'in' the river; a definite 'no no' according to the salmon habitat regulations. The undershot wheel is 'above' the water and only a small part is touching the surface of the river. With a 12" depth of water and 6" immersion there is still 6" of water for the fish to swim past the wheel. Additonal torque can be obtained by making the wheel wider up to the full width of the creek. By supporting the bearing supports on pontoons floating on the water the entire assembly rides up and down with changing water levels over the season. while maintaining a constant immersion level. Water levels will often rise 6" or more immediately following rainfall higher up in the mountains. For this particular application (powering a single family homestead) even 3 - 5 kW generation is plenty.

Not really a very good idea to make the blades movable. As the blades fill or are subjected to the influence of the moving water, and then collapse or fold on the opposite of the center said water wheel the balance of said wheel is impacted as the wheel is no longer round but is now elliptical. This creates an oscillating effect and and places a greater amount of ware on the center pin.

There exists, a simple little pumping device that is used with the common hand held electric drill that uses the principal that you present. The wheel itself is actually constructed of a flexible material so as to conform to the interior shape of the pump. They work well until the fatigue factor from the constant flexing impacts the wheel.

TMF

Hello,

We actually have 1 mile of creek but there is a 400ft sectiion close to our house that I could get the 10ft drop from.

We are in the tropics so when it rains it pours so to speak, causing flash floods of 15ft above normal....nothing to play with... I had concrete stairs down to our swimming hole that i built using pieces of 10 ft rebar 1" dia hammered into the bank and welded to the reinforcing rebar in the construction of the stairs.....it lasted a few floods but got torn out and sits some mile down stream and weighed a few tons. So it would be nice to place the pipe in the river but to fasten it and the cost of 400ft of large pipe seems a bit too much to risk. Good idea though.

The low head gen set: I am not aware of anyone selling these in North America. Do not have the link to the one stated but a similar one I was looking at is http://www.powerpal.com/ The one I found had a 3ft head diameter and six foot shaft and weighed around 1000lbs. I will not search for it right now as it will be probably a year before I can find the time to complete the canal and gates so there might be something better along the same lines by then.

Unfortunately I can not see how I could place an overshot wheel in this river.

We are fortunate in some ways that we do not have many laws regarding our waterways, the only one I am aware of here is no polutants. Constructing a dam in this large deep fast flowing river poses a problem for a single man and equipment.

Sling pumps are great as well as my ram pump but full time in the river is not safe, thats the other reason for the canal so I can put a couple of my small ram pumps in.

I was hoping for a floating undershot wheel but my electric needs are too great, we use around 40 kwhrs in 24 hrs.

Toomuchfun: Yes have already realised that was a silly idea and got some straight replys which were quick and very helpful.

Thanks to all here, always helps to think out aloud.

Quentin

Belize

20 of these would give you your 40kVA. (assuming some specs on your setup) Cantilever them into the river and adjust manually or with floats for river levels. 40k/day is a lot for a house, you must have something else going on too?

http://www.nooutage.com/aquair-uw.htm

It doesn't sound to me like you have a feasible hydroelectric source. 3m of head over 120m would require a large flow of water, and an expensive dam and diversion channel/head race. An Archimedes Screw turbine would work well in such a scenario and would probably be the most cost effective. I am very concerned by 15ft /4.5m of flood water. Everything would be swamped in such a scenario, and the forces involved would inevitably do a lot of damage.

I think you'll be pioneering a new field in hydroelectrics with a floating wheel, but it might be possible. Best of luck.

Here's an interesting solution. It's a vertical axis hydro turbine. A few of these on a floating pontoon (fitted with deflectors for logs etc) could do the job.

That looks interesting. I would like to see more on this. What kind of river speed Does it need to make electricity? How much torque can you get? Drew

I found it on the Absak site. The optimum flow speed is around 3m/s (10ft/s), which is very fast considering the depth that is also required (about 1m or 3ft for the 5kw model). It's called EnCurrent. Expensive at $28k, but everything is included.

Interesting concept, particularly if there is a decent marinised version (suitable for tidal flows).

http://www.floatingwaterwheel.co.za/

this one seems to work ok

but is a bit clumsy looking and doent look optimal

http://www.hydro-electric-barrel.com/

this one looks great but i dont think it works

the blades dont have enough grip on the water to gain power i think

but the backend does lift off the water cleanly and it should be rugged and reliable

I have a stream and like the idea of floating water wheel

I dont yet see an optimum blade design- flate - curved- vshaped- fenced in at the sides or high aspect ratio so the sides dont matter, solid center or open to allow stray water free passage?

pleased i found this forum

edwin

Floating Turbine at Hydro-Turbine.com

Quentin,

Please persevere in your effort to tap the kinetic energy of the river. Remember, wind has no head either. Conduct your own experiments and see for yourself.

Vince