A rather neat green power project

Steven Lake
Steven Lake Solar Expert Posts: 402 ✭✭
in General Solar Power Topics #1
Hey guys, I ran across a rather neat green power project that someone around here created (I don't have a link because it was told to me personally, so if someone finds a link to this, that'd be awesome, because it's a really neat project) to power their home with green energy. Ok, here's how it works.

The guy who built this has a 100ft tall home water tower that holds a very large water tank at the top (not sure how big, they didn't say), and on top of that is mounted a windmill that pumps water from a nearby river into the tank. The water from the tank is then fed down into a pair of micro-hydro generators which convert the energy to 24vdc which is fed into a bank of very high amp hour batteries. The used water from the generators is then fed back into the river.

From there power is fed into the house using a standard inverter system. However, from what I was told, this system doesn't have an "idle" state. it apparently goes to sleep whenever its not being used and only fires up just enough to provide the needed current, thus reducing overall power consumption and nearly eliminating the "vampire energy" drawn by normal inverters. I don't know what it is (if my guess is right, it's a load sensing, multi-inverter system, likely a custom job), but it can power a full house with no problem.

As for the water system, apparently the hydro system is also computer controlled. When the batteries are fully charged, or reach a given level, the valve at the top of the tower is shut and the generators spin down. When they're needed again after the batteries drop below a given level, they power back up. Same goes if the water in the tower gets too low, they'll power down until there's enough capacity to start them up again. Also, the water tower has enough capacity to keep the hydro generators running for quite some time, so even in a no-wind situation, it can go for some time without wind before the tank goes dry.

Anyhow, that's the story I was told. What degrees of true it is, I don't know. But given what I've heard about the guy who owns it, I'm willing to believe it's true. Especially given that he's an engineer for a living. lol. Anyhow, I thought you guys would find it interesting, so I just wanted to share it with you. Heck, it might even give you guys a few ideas to work with. :)
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: A rather neat green power project

    Entirely plausible.
    Providing you have the wind necessary to lift the water that high and also have the water. This is basically storing the potential energy as water at a height. There are even plans for commercial power storage systems similar to this. It's a good one, under the right circumstances.

    Lots of inverters will go into a sort of "sleep" or "search" mode and wait for a minimum draw to "fire up", thus using no power when no power is needed.

    Over-all, it's a good plan and technically very interesting. I bet lots of the folk here would love to see some details! :D
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #3
    Re: A rather neat green power project

    It is possible--but probably not practical... One would need a pretty large tank of water 100' in the air to store more energy than a 2-4 golf cart batteries...

    I believe they use "hydro" to recover energy in hilly areas for city water (at least I have read about it in our area).

    But that is not a cheap project to put many tons of water on a 100' tower.

    From another thread; 5,000 gallons (~20 tons of water) at ~47 feet elevation:
    BB. wrote: »
    You can use a site like this:

    http://www.oregon.gov/ENERGY/RENEW/Hydro/Hydro_index.shtml

    To figure out how much power you can generate for 5,000 gallons of water:
    Gross Head x Flow x System Efficiency (in decimal equivalent) x C = Power (kW)
    C is a constant (the value is different in English and metric units).
    • 100 psi / 2.13 psi per foot * 1 cf/s * 0.55 turbine eff * 0.085 = 2.19 kWatts
    • note fixed 0.85 should be 0.085
    • 5,000 gallons * 1/7.48 gallons per cuft * 1/1cf per sec = 668 seconds = 11 minutes of power
    Looks like a lot of "work" for little "work"... 2kWatts for 11 minutes.

    A pair of 225 AH 6 volt Lead Acid Batteries:
    • 225 AH * 12 volts = 2,700 WH for batteries
    • 2,190 WH * 11min/60min per hour = 402 WH for above water system
    In this example, the batteries store 6.7x more energy than 5,000 gallons at 47 feet elevation.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Steven Lake
    Steven Lake Solar Expert Posts: 402 ✭✭
    #4
    Re: A rather neat green power project

    Hey, cool info guys! Yeah, I kinda figured it wasn't all that efficient, but just the sheer bravado to even build a system like that is interesting. Then again, this guy is supposed to be an engineer, so who knows. He may have built it more to prove a point than to actually power anything. Either way, I think it's a neat little concept. The one I think is even neater is the micro-hydro he's using. If you're near a river with sufficient water drop, they make an excellent system for green energy. Probably not as a stand alone solution. But if combined with wind and solar, you *should*, in theory anyways, have ample power for a fairly meaty system. :)
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
    Re: A rather neat green power project

    I have water on my property that comes from fairly high up the hill behind. Trouble is, by the time it cascades over the rocks to where I can get at it most of the energy is already gone. Then there's that little problem of it being frozen all Winter and dried up for a month or so in Summer.

    Hydro power has many of the same drawbacks as wind. There usually isn't as much power there as you think, and it's not as consistent as sun. The elevated storage tank solves at least one of those problems.

    Somewhere on this forum is a thread discussing using "extra" solar power to pump water to storage and then recover it through micro hydro. The main problem being the amount of losses incurred in converting the energy from electrical to mechanical to potential to kinetic to electrical again.
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  • Steven Lake
    Steven Lake Solar Expert Posts: 402 ✭✭
    #6
    Re: A rather neat green power project
    The main problem being the amount of losses incurred in converting the energy from electrical to mechanical to potential to kinetic to electrical again.
    lol. Yeah, I agree. It is quite the conundrum. Oddly though, I have heard of people successfully using both wind and solar to pump water up a hill into a covered cistern for the purpose of providing pressurized to a house. I know a few around here who do it, and a few out west in the desert. But all of them, save for a couple, do it because they're farmers and it's a great way to stockpile water under pressure for later use.

    Now speaking of micro-hydro, I'd be curious to see what kind of system you could come up with that would generate the required power levels to run a house, and what the volume of water, and/or pressure required would be to pull that off. I'm not actually going to do anything like that. I'm just asking to be curious. ;)
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #7
    Re: A rather neat green power project
    Steven Lake wrote: »
    Now speaking of micro-hydro, I'd be curious to see what kind of system you could come up with that would generate the required power levels to run a house, and what the volume of water, and/or pressure required would be to pull that off. I'm not actually going to do anything like that. I'm just asking to be curious. ;)

    http://ludens.cl/paradise/turbine/turbine.html
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  • Steven Lake
    Steven Lake Solar Expert Posts: 402 ✭✭
    #8
    Re: A rather neat green power project

    Wow, now that's just dang awesome. Quite involved too! I love how he had to engineer some of his own parts, including the transformer to make moving power from his generator to his house easier. :D
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  • tmarch
    tmarch Solar Expert Posts: 143 ✭✭
    #9
    Re: A rather neat green power project
    Steven Lake wrote: »
    lol. Yeah, I agree. It is quite the conundrum. Oddly though, I have heard of people successfully using both wind and solar to pump water up a hill into a covered cistern for the purpose of providing pressurized to a house. I know a few around here who do it, and a few out west in the desert. But all of them, save for a couple, do it because they're farmers and it's a great way to stockpile water under pressure for later use.

    I have this scenario planned, but decided to just drill a well at the higher elevation and use a solar pump to fill the supply tank. Less expensive than pumping the water up the incline, less line loss, less pipe, etc. My system will be mainly for livestock water, but will be capable of furnishing water for the house. I may be wrong, but lifting water is lifting water whatever the angle.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #10
    Re: A rather neat green power project

    Vertical lift is vertical lift in terms of potential energy... However, long pipe runs (shallow slopes) add a lot of friction so tends to have more losses.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • tmarch
    tmarch Solar Expert Posts: 143 ✭✭
    #11
    Re: A rather neat green power project

    Well things are slowly progressing with my plan.
    I have a 125 foot drop that covers 1/2 mile so going to pull in 2" pipe and reduce it at the connector, if my calculations are correct that will give me 50+ PSI.
    Now need to figure out what storage tank to use etc.
    Been awhile as my wife has been undergoing some health issues.
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  • bmet
    bmet Solar Expert Posts: 630 ✭✭
    #12
    Re: A rather neat green power project

    In my area, any new well is super expensive, and highly restricted. Only commercial interests can afford the regulation.
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  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    #13
    Re: A rather neat green power project

    For anyone interested in hydro power (mostly very old equipment), theses folks seem to have a lot of fun

    http://frenchri.ipower.com/index.html
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  • tmarch
    tmarch Solar Expert Posts: 143 ✭✭
    #14
    Re: A rather neat green power project
    bmet wrote: »
    In my area, any new well is super expensive, and highly restricted. Only commercial interests can afford the regulation.

    That's why I want to get it done NOW before the government gets too restrictive here.
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  • Steven Lake
    Steven Lake Solar Expert Posts: 402 ✭✭
    #15
    Re: A rather neat green power project

    Around here we don't have any issues getting wells. It's the gas and electric that everyone's so anal about around here. Man, they hit you with crazy rates, then toss on another huge lump of fees besides. Cripes, quite often at least 50% of my bill each month is nothing but "extra fees", taxes, and other stupid money leaching tools. So yeah, I feel your pain. It's why it's quickly becoming cheaper for me to go solar around here than electric anymore. People think I'm crazy to consider going off grid. I look at my power bill and think they're crazy for NOT going off grid. Oy.
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  • jagec
    jagec Solar Expert Posts: 157 ✭✭
    #16
    Re: A rather neat green power project
    Cariboocoot wrote: »
    Hydro power has many of the same drawbacks as wind. There usually isn't as much power there as you think, and it's not as consistent as sun. The elevated storage tank solves at least one of those problems.

    Really? Of course, the amount of power available does depend on elevation and flow rate, but as far as consistency goes, I'd argue that hydro is MORE consistent than the sun. Assuming that your stream or river doesn't freeze over, you should get power equivalent to the minimum yearly flow rate, 24/7/365, and if it DOES freeze over, it should still be consistent the other 3 months of the year...

    We had hydro at our house growing up, and aside from the times when a big storm would wash down a tree and knock out the intake, it worked pretty well.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #17
    Re: A rather neat green power project

    i agree hydro is smaller initially, but it is more consistent and available all day and night. just ask waynefromcanada. if you only have say a paltry 100w being produced from hydro, this is 2400wh over 24hrs. to get this from even 5hrs of full sun per day would be the equivalent to 2400/5=480w and translating that into stc ratings on pvs may go to 480/.77=623w in pv and that would be if the sun shines at least for 5 full suns every day without fail. few places on earth can claim that. if you were able to get 400w-500w consistent on hydro, many off gridders and some gt users would easily power their homes just with that. adding pv too for whatifs and a bit more power and it's smooth sailing for nearly all requirements that are conservative to begin with.
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  • Steven Lake
    Steven Lake Solar Expert Posts: 402 ✭✭
    #18
    Re: A rather neat green power project

    I have to agree with Niel. Hydro is probably the single most consistent form of green energy out there. Sure, it's got its drawbacks as well, but they're far fewer than any others I've seen. Heck, I wouldn't mind having a house in a place where I could easily get hydro power. Plus, as he said, even if it's only 100w, it's still better than solar due to the 24/7/365 principle. Yes, there are a few downsides to hydro, but not many. Here's a good list of the chief ones: http://www.alternative-energy-news.info/micro-hydro-power-pros-and-cons/
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  • Ken Marsh
    Ken Marsh Solar Expert Posts: 114 ✭✭✭✭
    #19
    Re: A rather neat green power project

    "the valve at the top of the tower"

    I hope "the engineer" figures out that he better locate the control valve at the bottom of the tower.
    Otherwise he will have one big water hammer.

    Km
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