Waterwheel to run generator

[billyjoebobd]

I have not found any articles which address this idea.

I've been looking at the ST generators from China. My plan is to create a diversion weir, with a cinder block shed next to it to house the generator. Not sure about the run length to the cabin as it is not built yet, and this idea is in its infancy. The creek flows year round and is about 15-20ft wide and 4ft deep on average. Not sure if I have enough head for an overshot wheel, but plenty of flow for a paddle or undershot wheel.

My question: Has anyone had experience with this setup? Is this a stupid idea? I am assuming a paddle wheel would generate enough HP to drive a large generator, say 20KW. I know there will be issues with freezing in the winter, unless I could somehow use the dump load to heat the weir and or wheel.

I'm not an electrical engineer or mathematician, and am not trying to offload the research. I'd just like to know if I'm wasting my time.

Thanx for any help.

[nick1234]

before you start to build anything take some measurements head lowest flow to see what you may have is this river on your property (your rights)

 how cold does it get in winter freeze up is there good flow at this time under the  ice  take pictures summer winter

 them come back with the info and then we will be able to help you

nick

qc.ca.

[billyjoebobd]

Sorry, I should have given more info. The creek dimensions I gave are in august when the creek is near it's lowest flow. It is quite a bit higher in the spring, from snow melt. Yes, I own the property and both banks of the creek. The creek has plenty of flow under the ice in winter, and stays open in several places where it flows over beaver dams. There is quite a bit of slope, but I don't want to have to run a long pipe to get the head for a micro hydro setup. The property is in Southwest Montana, and does get very cold. As far as flow goes. I am sure I have enough for any size diversion I might need.

[wdyasq]

Billyjoebobd,

You have given us dimensions but no numbers we can work with. You will need to setup a 'weir' and get a measure of the flow and drop, "head",  available.

If you don't understand this you will need to do enough research until you can 'talk the talk'. There are a lot here that will be able to help. Help can not extend to basic knowledge of the site, which usually only the owner can give.

You may have 20kW of power there, you may have 200w of power there. Until the quantity of water and the distance it 'falls' is known, we only know you have a stream.

"My car is pink, what size tires does my brother's car need?"

Ron

[divebuddy]

do a search for waterwheel by divebuddy. the one I built is now pumping up the mountain 140 feet vertical lift. Bob is getting 1 gallon every 75 seconds.What is an ST? acronyms are abundant so without reference they are meaningless.

[TomW]

divebuddy;

Your stories on the water wheel are over here:

http://www.fieldlines.com/story/2007/1/20/15324/6627

http://www.fieldlines.com/story/2007/9/2/173915/8438

http://www.fieldlines.com/story/2007/9/11/235538/617

Just to make it easier to see them.

I found those to be interesting use of a wheel.

Tom

[JW]

If it was me,

 Id get a section of 10 inch diameter pvc pipe(about 4 feet long) and mount an electric boat trolling motor in that(at about the centre). The propeller should fit inside the pvc pipe. Seal it all up, support the shaft, then force water thru the pipe.

 I would duct as much water as possible, thru that peice of 10in pvc tubing. also, since its a pm motor(for the trolling motor) it should do well, considering the inherent water cooling of the motor assy.

 Im sure some usable power could be extracted, with the given flow. It would be much easier to do that, then going thru the trouble of constructing a water wheel of equivent power extraction, which would have to be much larger, in physical size.

JW

[terry5732]

For an undershot forget about measuring head.

You need the width x average depth and flow rate.

Army manual TM 5-700 has some good information for stream calculation if you can find one. I don't know where mine is presently.

[spinningmagnets]

Here's some links I think will be helpful for commentators:

http://www.utterpower.com/ST.htm

Utterpower site description of ST gens.

http://www.putfile.com/dougwp/images/102508

pics of Jinlong ST alternator head disassembled

[spinningmagnets]

A wooden water wheel can be an affordable data-gathering device, but you should plan on ending up with a metal wheel.

In a location that experiences lengthy freeze-over when you want to get power from the wheel, I recall an old fieldlines post where someone was attempting a VAWT underwater, with the generator above water at the end of a short pier.

The leading edge was shielded from flow, and the trailing edge was driven by the current. The power shaft ran through a protective pipe that was located at the level of the ice cap. I haven't heard how it turned out, or what type of lower shaft bearing would be best.

The rim speed of a wheel will probably end up being about 90% of the water flow speed. To spin a generator fast enough to get decent power, you may need to use a "gear-up". A car differential "might" be able to be used as a 4:1 RPM increaser if spun backwards. If greater gear-up is needed, toothed rubber belts and chains can be found, but they are more expensive and have to be maintained and replaced when they wear out.

Before steam engines, breast-shot/hip-shot water wheels were the staple of many factories. If more torque was needed to get adequate gear-up, the wheel was made wider (Google DuPont gunpowder water wheel). If you make a VAWT underwater, you will be restricted to depth of stream at lowest annual level.

Depending on conditions at location, you may find wind is a better first effort from a cost/effort Return On Investment (ROI)

[JW]

Forgive me all, this link will seem a little redundant.

http://www.re-energy.ca/pdf/hydroelectric-generator.pdf

Im sure one could do better than spoons as the paddle wheels, but the design looks remarkably simular to what we see around here(on this site) at far as, the 4 magnet to 3 coil ratio. The design looks tempting as far as ease is concerned. Dont think it would matter all that much even if the stator was under-water.

I still stand by the trolling motor idea, its simple, effective, and outputs dc. You could easily have a water overflow at the inlet of the tube, to better match actual flow needs with whats available.

The only thing that causes concern for me, with any of these designs, is the possibilite of debris fouling operation and flow of the impeller.

I believe a water wheel(in the standard sense) would have less of a tendency to foul in this way, winter is most likely, not going to be a good season, for any design.

JW

[JW]

oh wow,

 seems there using four magnets to four coils, sorry about the miss-quote.

JW

[spinningmagnets]

I just did some looking into this idea, as it appealed to me and seemed feasable (a Francis turbine resembles a boat propellor), so I thought someone must have tried it before. I found some stuff, but I posted the best similar story here (only 7-foot of head via a weir/dam and flume):

http://www.fieldlines.com/story/2008/6/22/191210/965

[Ungrounded Lightning Rod]

The problem with using a trolling motor propeller as a water turbine is the same as the problem with using an aircraft propeller for a wind turbine:  The curvature is backward for the service.

For a propeller you want the convex side, with the lift, on the upstream side, to accelerate the water/air and pull the aircraft/boat forward, while putting drag on the rotation to transfer its energy to the fluid.  For a power-generating turbine you want the convex/lift on the downstream side, to decelerate the water/air and pull the turbine forward in its rotation, transferring the energy from the water/air to the turbine.

Using a stock prop will work.  But it will be acting purely as a drag turbine and not as efficient as one acting as a lift turbine.

Now you could replace the prop with one that has the proper shape.  But finding or making one might be problematic.

[spinningmagnets]

Thank you ULR, that was useful information. I apologize if this was off topic, billyjoebobd, I thought it was be an option you might consider. (disclaimer: I haven't built any hydro yet)  

[joestue]

How long do you think a cast aluminum prop would last?

(Assuming it has been heavily anodized.)

[JW]

Most trolling (electric) motors use a pretty durable plastic prop(weedless too).

  Im not going to go into the hydro-dynamics of a prop thats intended to push, but...

  If one stuck a 12v or a 24v trolling motor in a stream that was fast moving, without the duct-mounting(12in pvc tube) you could by-pass all the speed-control electronics, take the red and black wires straight off of the shaft, touch them together and they would spark, most likely this would not burn out a commutor.

 Im sure some loading on the shaft that suspended the motor(pointed end facing water current ov'coarse) in the water flow would occur, as you shorted output. Yes, the lower end of a trolling motor housing is water-proof, but this doesnt mean you dont have to protect rain-fall from entering the housing thru the top of the shaft.

 this would be a purely mechanical arrangement,since it has brushes, with no rectifiers or bridge semi-conductors. One could adjust nominal voltage output, with an overflow using the duct housing for the generator assy. Obviously these conditions would change thru out the season,(you'd have to adjust overflow) but you could extract only so much from the arrangement anyway, so its 'ok'.

JW

[joestue]

I don't want to start going on about what efficiency that system you just described would get, but certainly for the simplicity of it, you might as well just do it.

Anyway I brought up the option of casting an aluminum prop, just because it is so easy, and 10 times cheaper than a brass one. although plastic is certainly an option, for those who have some experience with it.