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Energy from Water

  1. Dec 20, 2007 #1
    How much energy can you get from water? For example can you use a water mains safely to turn into energy? i.e. harness the energy somehow from the water in a pipe? Is it possible? Would you get much energy out of it?
     
    Last edited: Dec 20, 2007
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  3. Dec 20, 2007 #2

    DaveC426913

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    I assume you mean the potential energy from falling water, like a hydroelectric dam, not like chemical or nuclear.

    You could extract a little bit of energy on a small scale but you'd be tapping into the city's mains to extract it where a pipe went vertical. They'd frown on that. Especially since it would (by the nature of extracting potential energy) slow the progress of the water. Which they'd definitely frown on.
     
  4. Dec 20, 2007 #3

    rbj

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    i don't know of any chemical energy that can be had from water, but i s'pose a plant that extracts H2O from some large body (like an ocean or Lake Michigan or something) and centrifuges for H2O with one or both hydrogen atoms being heavy, and from that running some nuclear fusion reactor, that might be in the cards with acheivable technology someday. i don't think it is now.
     
  5. Dec 20, 2007 #4

    RonL

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    In most cases a city has a water tower, they buy electric power to run the pump that fills the tower in order for you to have pressure on your main, pressure alone would leave you far in the hole.
    Now if you talk the city, into a system where pressure, and heat would be used, then in a closed loop system using both forms of energy might be worth a look? ( a micro-geothermal system)
     
  6. Dec 20, 2007 #5
    What about the mains and pipe that run underneath a road - is there a sufficient temperature difference for thermoelectric energy or a turbine in the main or any other types of ways to harness some sort of energy.....
     
  7. Dec 20, 2007 #6

    RonL

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    Well i didn't think about how much i'd pay to heat the ice cold water that comes into the hot water heater:redface:
     
  8. Dec 20, 2007 #7
    Richie any energy you could pull from the moving water in a pipe leads to it slowing down, which means the city has to put more energy into it to keep the pressure up.

    Is there free energy to be had? Yes for the first few who do it, but it is a small amount anyway. And as soon as the city sees the drop they'll just increase the cost of water to be able to pay to increase the energy of the main.
     
  9. Dec 21, 2007 #8
    I have good links with the water company - so if i had access to the main and the pressure was sustained to the customers at the same time - i could do something with flow/pressure?
     
  10. Dec 21, 2007 #9
    it is un feasable to split h2o into its componets just to burn h2 for energy it takes twice as much energy to split the h2o into its componets thats why all water to hydrogen fuiling stations run on solar power if they were conected to the power grid electric prices would skyrocket
     
  11. Dec 21, 2007 #10
    I think hes talking about stealing energy from the pressure in your water lines, not electrolysis.

    But richie, let me stress, while in theory you WOULD get energy out of the system, it would be minimal. Look at these points:
    1. To get the energy water would have to be constantly flowing == money.
    2. The small time you do run water consider this:
    How much energy do you think is required to push water through your pipes at the rate it comes out at? I figure I can get an electric pump thats quite small to do the job, and only run it at a medium pace. Thats not much energy requirement to do the work. Then look at it backward, thats the maximum energy you could ever possibly get out. Enough to charge a a couple of D batteries most likely. Not enough to consider building anything to harness.
     
  12. Dec 21, 2007 #11
    Lol - i am not talking about stealing energy or doing anything illegal!! It is just a science project we are doing and one idea I came up with was around using the flow of water in pipes - e.g. use a turbine in the pipe to create some type of energy output - yes it would reduce the pressure but if the main was 12" or bigger it would not affect customers especially if its a mini turbine.
     
  13. Dec 21, 2007 #12

    russ_watters

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    It doesn't matter how small it is, it is still stealing energy from the water company. Water companies have enormous electric bills due to the energy it requires to pump that water.

    Now if you wanted to do it in your own home, sure, you could, but I suspect the electricity you got would cost more than from the wall socket due to the cost of the water that you are pouring down the drain.
     
  14. Dec 21, 2007 #13

    Dale

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    You can easily get enough energy to wind up your garden hose!

    http://www.no-crank.com/

    Energy is pressure times volume, and you can build devices that are reasonably efficient at converting the energy in the water into mechanical work. As russ mentioned it is a net energy loser and a net money loser as well since most of the hydrodynamic energy in the water was added by electric pumps.
     
    Last edited: Dec 21, 2007
  15. Dec 21, 2007 #14
    Sorry About My Earler Post Read Rbj's Post About H20 And Wanted To Throw My 2 Cents In Well About The Subject Cant You Take A 12 In Main Put Lets Say A 1 In Fitting On It Wich Would Make The Speed And Pressure Far Grater Hook Up A Small Water Pump Backwords Like You See On Old Well Pumps Then Reverse The Power Connection On The Moter So That It Feeds Power To The System Instead Of Taking Away That Should Produce Quit A Bit Of Power Or Just Hook Up A Small Turbin
    On Another Not Woudent The Pressure Be Able To Cut A Man In Two
     
  16. Dec 21, 2007 #15

    russ_watters

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    Capitalizing the first letter of every word makes your post extremely difficult to read. Just fyi, this isn't like other forums - we prefer people to speak proper english.

    Anway, no the pressure in a city water main isn't so high that it could cut into you. That's something that can happen with high pressure boilers, but they run at a good 10x the pressure of a city supply main.
     
  17. Dec 21, 2007 #16

    DaveC426913

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    Keep in mind that this is not waste energy you are collecting. The purpose of these water lines is to keep water moving efficiently, which would be directly counterposed by your system. It's not quite the same as taking energy of a source that is otherwise being wasted, such as a lake or river at altitude.
     
  18. Dec 21, 2007 #17
    sory about the capitalizing and misspelling i did not graduate high school but dont forget that you are forcing the pressure and mass for a 12in pipe main threw a 1 in hole wich would give it alot of force
     
  19. Dec 21, 2007 #18

    russ_watters

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    No, pressure is pressure - the size of the hole doesn't affect that.
     
  20. Dec 21, 2007 #19
    think of it like your garden hose when you close the tip almost all the way you get a jet stream that is more powerfull that can blast dirt away with the right tip on a garden hose you can pierce skin i now i got a skar on my back because of one
     
  21. Dec 21, 2007 #20

    DaveC426913

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    You cannot extract more energy from a garden hose with a small hole than you can from a garden hose with a large hole. You will not fill your swimming pool faster with a smaller hole.

    Nor can you extract more energy from a water pipe regardless of how big or small a hole you make in it.

    I can't break your skin using my thumb but if I tape a thumbtack to my thumb I can break your skin. I've have not used any more energy, I have merely concentrated what energy I have available on a smaller point.
     
    Last edited: Dec 21, 2007
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