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Any "real engineers" on here?

  1. #1
    Senior Member wagspe208's Avatar
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    Default Any "real engineers" on here?

    OK, here goes.... since my shit burned to the ground I have some spare time. I want to make some green energy. Now, before you quit reading... look...
    I have a lake that will be 15 acres. I want to build a waterwheel. Not one of those pansy paddle wheel water wheels, a real old style water wheel.
    I couud use a Pelton wheel, but my drop is only about 20'. I am afraid it is not enough drop to power a pelton (yes, I have one from the late 1800's, or early 1900's) They use less water. Also, much less torque.
    So, if a water wheel could grind flour, or run a saw mill, why not run my generator?
    So, here is what we have:
    20' drop
    15 acre lake... it has hundreds of acres of run off into it. I have an 8" drain pipe. I opened the pipe for a week, had 1.5" of rain, lake was at the same level with draining constant + rain.
    I'd like to run a 5k generator (but 3K would probably be more than enough for most of the time)
    I understand I will not be able to run the gen all the time.... but:
    15 acres x 43500 (sq. ft per acre)(rounding here)=652600 sq. ft.
    If I only allow 1' water drop that equals 652600 sq. ft x 1' depth = 652600 cubic ft. of water.
    now, cu ft x 7.48052= gallons.... so that equals 4,881,039 gallons. Let's round it to 4,800,000 gallons.... easier.
    Now, here comes my questions.... what size drain pipe do I need with what size water wheel to run the generator.
    I am struggling to find flow per min of an 8" pipe.

    Wags

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  3. #2
    Senior Member wagspe208's Avatar
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    OK, for the wheel "axle" I was thinking of using a 1 ton truck axle. Sealed, easy obtainable, gear ratio to speed up output rpm. A bunch of frictional loss is down side. So, possible to directly shaft drive a generator. (relatively easy setup)
    I was thinking of a wheel on only one side... well, then I have a huge weight offset from side to side... so I think that dictates a narrower wheel on both sides of the axle.
    I was going to install my "feed pipe" under the main drain spillway, or drain pipes. That way, I can shut off water to the wheel, with a valve, and wait to open it back up when water gets back up to spillway pipe level.
    So, wheel diameter is open. Obviously the bigger the more $$$$. Required flow in gal per minute. Pipe size to obtain that.
    AND believe it or not, there aren't many water wheel plans at home depot. HAHA
    So, what do you think? Crazy, sure. Doable, sure..
    Oh, I am not planning on a stand alone system. It will be grid tie.
    I need to invert to ac power due to distance reasons. Also, needs to be clean.
    Wags

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    Senior Member wagspe208's Avatar
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    OK, so I think I found an 8" pipe flows about 100 gpm. I'd believe that. That is 6000 gph. At this rate that valve can run wide open for 800 hours?? = 33 days? Sounds way high.
    This obviously does not account for evaporation. It also does not allow for any rain, nor the springs that run into the lake.
    Wags

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    Senior Member ol guy's Avatar
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    WOW!!! I can't wait to see the response on this! Old school energy with new school technology. Did you think about a battery bank and inverter set up to store and supply? Reason I say that is water supply and charge generated by water flow! If the water flows 24-7 then let her rip. Flow reduction ( I mean reducing diameter of water feeding the wheel faster will create more pressure and keep the wheel turning (so to speak) . If you have the ability to create a storage tank up river, the flow will not stop, may slow down RPM of the generator but you need to channel water to the holding tank to keep it fed!

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    Senior Member wagspe208's Avatar
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    I thought it would be interesting... sure, not engine related, but sure as hell torque and rpm related.
    Wags

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    Default inverters

    look into building the generator " inverter style" so you can store the energy and use the water wheel to recharge the system. To tie into the grid you will have to maintain and sync the 60 hz. i think that would be tough using water flow controls over the wheel considering load changes (motor starting etc),. A huge flywheel maybe. Even if you ran all your single phase off the wheel and bought your 3 phase the savings would add up.

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    steelcomp was here
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    You have the weight of the water times the lever of the water wheel...you should be able to calculate tq/hp @ the shaft of the water wheel. Find out what rpm and what the power requirement for the generator is. Gear accordingly if you have enough power.
    If the water is just falling, then I'd think sheer volume will be key, not trying to create velocity, but there may be a balance between the two. I know when they were doing erosion mining in northern CA they made huge water cannons by building flumes that brought water down from the mountain and ran it into/through a big nozzle at some outrageous pressures. That would spin yer wheel...
    Last edited by scott foxwell; 04-29-2013 at 05:56 PM.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    Senior Member uniboarder's Avatar
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    Since it is an 8" drain feed line vs. pressured line make sure air reliefs are installed in any high points, otherwise you can air lock or simply not get the flow you are calculating for. My father in law built one in his moms back yard stream just to do it, it was cool. I am sure he would love to talk to you about it. He has been live aboard on a sailboat in the Carribean for two years so sometimes it takes a day or two to get an email response. [email protected] They power their boat mostly from solar and Jim has been tinkering with wind turbines.

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    Senior Member jms-1's Avatar
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    Don't forget to paint the wheel silver, It will add some torque for sure....

  12. #10
    Ain't Right Racin piston in the wind's Avatar
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    Take all that water $ grow some weed problem solved & it's green... Then take what you don't use goin green & use it to cool a condenser & make some shine,& what you don't drink you can race on the left overs get in touch with Unchained... Nothing waisted still green... life is good til you get busted. Then blow the dam & destroy the pot field & the still with the flood waters no worries... I think... looks good on paper...I should've been a civil engineer
    QE 2050 W/ a Junk ass screw blower

    90% of the game is half mental... The pursuit of the unknown is priceless & gratifying . Sometimes it just takes good old fashion balls. No amount of reasoning or evaluation can deem it right or wrong. At the end of the day stick with whatever gives the person in question morning wood LOL

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    Go to the library and check out an engineering book from the 1800's.
    I assume thats how our forefathers did it when they made their water wheels that seemed to work in the wilderness.
    Surly, we're better educated than they were.
    Some of us may not be though.

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    gn7
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    GEEZ, all the talk in here about the difference between torque and HP.
    Just because out ancestors managed to use a water wheel to SLOWLY grind grain is no indication that you can generate enough TORQUE to convert to RPM and HORSEPOWER to run a generator. Unless you talking about a generator out of a 1955 Chevy.
    We tried this on my boss' ranch in Montana and the step up overdrive gear box ate up way too much power.

    I'm with Piston in the Wind on this. Plant Monsanto corn for ethanol and a "sub crop" between the rows. Works for the Hawaiians in the cane fields



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    Senior Member 66sanger's Avatar
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    Default awesome!

    Awesome project!

    I would love to do something like that, if I had a location that worked!

    I would consider an undershot waterwheel though. It sounds like you have enough height for an overshot, but building a penstock and sluice way out of rocks and concrete seems easier to me. Then a simple penstock gate could control your water supply.

    I really like this guys setup - but it's a little smaller than you are looking at!

    http://www.builditsolar.com/Projects/Hydro/UnderShot/WaterWheel.htm

    This website has tons of green energy DIY projects, I especially love the micro hydro stuff, it is the absolute best way to generate clean electricity!

    http://www.builditsolar.com/index.htm

    Good luck!
    Eric Armstrong

  16. #14
    Senior Member 66sanger's Avatar
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    Default more websites

    Well I reread your post, and for some reason I can't use the return key on this website. Sorry is this one ridiculous run-on. I used the calculator on this website RockyHydro's Free micro-hydro calculator and got 200 watts available to you. The bonus of the 8" pipe is virtually no friction loss. The downside of 100 gph flow, it that isn't very much. This website, was interesting: http://sleekfreak.ath.cx:81/3wdev/VI...1/WTRWHLOS.HTM is a pretty useful "how-to" build a waterwheel. They also use a rear axle, but for you, I was thinking would probably need to use a motorcycle chain drive setup to get the rpm's that you will need for a generator. http://builditsolar.com/Projects/Hyd...HydroGuide.pdf Canada has this microhydro guide that has the equation I used. From GPM/GPH Flow based on PVC Pipe Size, ie, How much water can flow through Sch 40 Pvc Pipe Size 1/2" 3/4" 1" 1.5" 2" 2.5" 3" 4" 6" - an 8" pipe at low pressure (about 6 ft/sec velocity) will flow 57,000 gph. From the Canada guide Pth=Q x H X g. Pth is Theoretical Power in kW, Q is usable flow rate in cubic meters /sec, H is gross head in meters, and g is gravitational constant 9.8 meters/sec. So, 57,000 gph is 0.05994 cubic meters per sec and 20 feet is 6.096 meters. That gives us .05994 x 6.096 x 9.8 = 3.58kW, or about 4.8 horsepower. Given that, you should be able to turn this: NorthStar Belt-Driven Generator Head — 2900 Watt | Generator Heads| Northern Tool + Equipment constantly, 24 hours a day! There are going to be efficiency losses, but I think this actually underestimates potential flow. The most important thing to asses here is actual flow coming out of the pipe. To do that, you are going to have to determine water velocity at the outflow pipe. They discuss some methods for doing that here: http://builditsolar.com/Projects/Hyd...neAppendix.pdf Goodluck!
    Eric Armstrong

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