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Thread: Hydro power from small streams?

  1. #21
    Regular+ User Grey Knight NFO's Avatar
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    reducing losses between hydro turbine and house

    Quote Originally Posted by hammerhead 67 View Post
    There is a year round creek/stream on the back side of the property we hope to build on.

    Its a long way from the build site but we could use a power supply on that end of the property to run irrigation pumps.

    Has anyone seen a small/affordable hydro system that would work on a creek/stream to generate enough juice to run an irrigation pump?

    Thanks.
    The easiest way to reduce electrical losses between the generator and your build sites is to use high voltage AC. This also allows for smaller gauge wires, because the current is minimized. Use a regulated AC generator on the hydro, send it through a transformer to up the voltage and then use another transformer at the house to drop the voltage to 220 or 110 as needed. The beauty of using HV is that the power (Volt-Amps), is higher with less current, reducing the effect of resistive line losses. Furthermore, AC has inherently less line loss than does DC. (For more on that, refer to the Tesla vs Edison battle of the 1880s and 1890s.) Just be very careful with it, because electricity can kill. (Avoid high amperage lines, they are much more deadly than high voltage lines.) BTW, at 5kV, 0.11A delivers the same amount of power as 5 Amps at 110V. If your line from your generator has a resistance of 1 ohm per 100 feet, and you have 500 ft of line, at 5 amps, your loss will be (5 ohm)*(5 Amp)^2 = 125 Watts, whereas, on the same line, if you run it at 5kV, your loss will be (5 ohm)*(0.11 Amp)^2 = 0.0605 Watts. This is why they run million volt HV lines from commercial power generators. However, if you plan to use HV, you will need to keep it very well insulated to avoid shorting.

    Steve

  2. #22
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    That's all true. What would be a good estimate of the losses in the two added transformers?


    Peter

  3. #23
    LHBA Member project's Avatar
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    I can't comment on the loss through the transformers but I can tell you that they can get expensive. I have a cb radio that has a HV power supply and just the transformer cost over $1000. If you have a good water supply that runs year round then it could be worth it but might get expensive to experiment.

  4. #24
    LHBA Member StressMan79's Avatar
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    you can look up a lot of stuff here

    http://en.wikipedia.org/wiki/Transformer

    looks like you will generally be running "no load" and then
    Winding resistanceCurrent flowing through the windings causes resistive heating of the conductors. At higher frequencies, skin effect and proximity effect create additional winding resistance and losses.
    will dominate. There are lots of other loss mechanisms you can look at too.

    but as a compromise, you may look at running @ 220 Vac, 50Hz, and use European stuff. half the current and losses, and no expensive transformers.

    anyway, unless you live more than a mile from the Hydro, I would think that the losses would be small, in relation to the use.

    Oh yeah, I'd run a battery bank, so you could have a 220 V or even 440 VAC input, running a 48 VDC bank. Run 1 amp through your charge controller into your batteries, then invert them to whatever you need at the house. That is 440W, or 3.4amps out your inverter @ 110VAC, that is not enough for a whole house, but on average, 440*24*.85=9 kw-hr/day. That would prolly do it, and you would have minimal losses (very small losses through any copper @ 1 amp).

    -Peter

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