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Solar hydrogen

Discussion in 'Home Power and Microgeneration' started by AssTelescope, Jan 18, 2005.

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  1. AssTelescope

    AssTelescope Guest

    Hi,

    Has anyone done any experiments using solar concentration to extract
    hydrogen from water and use it to drive a motor instead of storing it in
    batter banks. I understand that it requires 5000C for a very efficient setup
    but a small sized dish can reach approx 750C so it wouldent be an impossible
    task at all.

    This to me would seem more efficient as it can also be used for cooking
    also.

    Another question if I were to give this a go, how would I store the
    hydrogen?

    Thanks,
     
  2. Steve Spence

    Steve Spence Guest

  3. Steve Spence

    Steve Spence Guest

  4. Steve Spence

    Steve Spence Guest

  5. Andy Baker

    Andy Baker Guest

    Agreed. Hydrogen blows unless you can burn it in a nuclear reactor and
    that's a whole other story. The only reason we hear so much about hydrogen
    is because it can be extracted from oil and look where that gets us, though
    I did hear ( somewhere) that onboard reforming of petroleum to fuel cell to
    electric motor, despite the extra steps, yielded much better MPG ratings.
    There was a great article not too long ago in popular science that read
    something like "1001 reasons why hydrogen is a giant waste of time and
    money"

    On algae to animal feed, I've heard of farmers throwing chicken manure in to
    the water to cause algae blooms which the shrimp feed off.... sounds yummy.
    I'm POSITIVE they sterilize that chicken shit really well.....yeah.....

    Andy

    | You won't want to "give it a go". It's not a backyard science project.
    | It might give you a "go". Storage requires compression and metal
    | hydrides, expensive technical processes. This is interesting, but it's
    | not homepower or pv. Try sci.energy
    |
    | Steve Spence
    | Dir., Green Trust
    | http://www.green-trust.org
    |
    | Contributing Editor
    | http://www.off-grid.net
    | http://www.rebelwolf.com/essn.html
     
  6. AssTelescope

    AssTelescope Guest

    Ok maybe storage is what may stop me from doing this and the danger
    involved.

    But I do see it more efficient than electrolysis seeing you need electricity
    in the first place. I guess I thought of a flammable gas that can be used
    for anything, much like natural gas is used in cars and cooking today, so
    when I saw an article on solar concentration for hydrogen extraction I put
    two and two together, obviously it doesn't add up to 4.

    Either way, I haven't got enough cash to spend on storage tanks or a reactor
    for that matter!

    Thanks for the replies everyone.

    As for the Biodiesel replies, I don't think its practical, I still think
    using the sun as my main power source is the way to go. After all, the Sun
    is the reason we are all here and its given us energy since the dawn of
    time.

    Cheers,
     
  7. Jim Logajan

    Jim Logajan Guest

    I don't think so. The primary reason hydrogen has a lot of interest among
    some researchers is because the primary exhaust product contains NO carbon
    dioxide. If the primary source of energy in future economies is going to be
    solar or nuclear, then any ecologically neutral intermediate storage
    mechanisms should sink as much of their exhaust products as they source. If
    someone has a moderately efficient way to make hydrocarbon fuels using only
    solar/nuclear, atmospheric CO2, and water then there is no need to consider
    hydrogen. I suspect hydrogen will "stay in play" as a possibility until
    someone comes up with a mechanism for high density energy storage
    comparable to hydrocarbon fuels but none of the exhaust problems.

    It's an engineering problem that includes not just efficiency as a
    requirement, but a requirement that the storage mechanisms be
    environmentally benign for usage over thousands of years for the entire
    human race. Anyone fixating on efficiency is solving the wrong engineering
    problem.

    All IMHO of course.
     
  8. Urban lore.

    No means of producing terrestral hydrogen is known that does not create
    substantial amounts of carbon dioxide. Typically much MORE so than
    alternatives.

    The sensible and practical goal should be a carbon neutral room
    temperature liquid, not a carbon free one.

    See http://www.tinaja.com/glib/energfun.pdf


    --
    Many thanks,

    Don Lancaster
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    voice: (928)428-4073 email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  9. Not so. No _reasonably efficient_ process exists. I can generate Hydrogen
    right now without creating any CO2, from my solar/wind installation. I
    can't _do_ anything with the hydrogen...
     
  10. Triples the losses.
    Not one net watthour of pv solar electricity has ever been produced to
    date.

    Also, there are ridiculously better things to do with electricity than
    destroy most of its exergy through electrolysis.

    See http://www.tinaja.com/glib/energfun.pdf for a detailed analysis.

    --
    Many thanks,

    Don Lancaster
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    voice: (928)428-4073 email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  11. Dream on.

    If you objectively look at the staggering loss of exergy in your method,
    you will realize how ridiculous it is.

    Thermodynamic fundamentals GUARANTEE that the value of a kilowatt hour
    of electrical energy is absurdly higher than the value of a kilowatt
    hour hour of unprocessed hydrogen gas. Your process is exactly the same
    as 1:1 exchanging US dollars for Mexican pesos.

    See http://www.tinaja.com/glib/energfun.pdf for a detailed analysis.

    Also, when fully burdened and truly accounted, your solar/wind
    installation generates HUGE amounts of CO2 if used to produce hydrogen
    gas.

    --
    Many thanks,

    Don Lancaster
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    voice: (928)428-4073 email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  12. I have no intention of dreaming about it at all. I don't happen to think
    the "hydrogen economy" is either desirable or particularly achievable.
    Don't be an ass. I agreed it wasn't economically feasible. _You_ said it
    wasn't _possible_. There's no CO2 involved in the PV process. I'll grant
    you that there's CO2 in the production of the components - but strictly,
    most of the components in a PV array should be _waste_ products of the
    silicon chip industry.
    What I _use_ the system for is irrelevant - unless it's to somehow drill for
    fossil fuels. When "fully burdened and truly accounted", I'll worry much
    more about the heavy metals in the batteries and the PV array.
     
  13. Most of world's electricity is produced in coal-fired power stations.
    Rather than producing hydrogen wouldn't it be better to use the extra
    nuclear, wind or solar power to substitute dirty coal (or natural gas)?
    When all fossil power has been replaced in year 3000, we can rethink
    hydrogen via electrolysis.
     
  14. And bio-alcohols aren't, why? Still no way to make them without inputting
    more energy than we get out?
     
  15. bee

    bee Guest

    "Carbon free" fuels ain't gonna happen.

    See http://www.tinaja.com/glib/energfun.pdf
     
  16. Sailors recently injured on the *San Francisco*
    have reason to disagree.


    -- Graham Cowan, former hydrogen fan
    http://www.eagle.ca/~gcowan/Paper_for_11th_CHC.html --
    How individual mobility gains nuclear cachet
     
  17. That's why I didn't say "and bio-ethanol and bio-methanol aren't, why?".


    So here goes:

    Why aren't bio-ethanol and bio-methanol environmentally friendly?
     
  18. I'm a fair and reasonable person. I read that, and I would agree with
    almost all of it. Your "fully burdened and truly accounted", though, is
    highly debatable. On a pure accounting basis, my system is no _more_
    expensive than connecting to the commercial grid, so I just don't buy that
    argument. To say "If your solar panel is generating two cents worth of
    electricity a day and the interest cost is three cents a day, you have a
    net energysink" fails to "fully burden" the cost of commercial energy. The
    subsidies available for production of fossil fuels are staggering. The
    subsidies that have been given to nuclear can't even yet be measured as
    nobody knows who's going to pay for spent fuel storage and decommissioning.
    Meanwhile, my PV/wind system actually produces about 15 cents of
    electricity per day, but there are no interest costs because the capital
    expense to bring in grid power was (approximately) the same as solar, and
    also if I was on-grid, you can bet I'd be spending _more_ than $0.15/day on
    electricity. I'd have to go back to the total fuel bills for the past few
    years to know how much, because I'm not now using electricity for some
    things I did when I was on-grid - range, hot water & fridge - but there's
    definitely a lower total bill, even though fuel costs of all kinds are
    higher than where I used to live.

    All that said, I generally recommend _against_ installing solar or wind
    generators for people who have available grid connections.

    "Excessively annoyed pond scum also can apparently produce hydrogen". I
    think if you call people pond scum, it goes without saying that they'll be
    excessively annoyed, but I've never seen them give off hydrogen. :)
     
  19. Pretty much. Remember, for the alcohols, you have a double process.

    First, you have to grow the grain, which requires quite an energy
    budget. Then, you have to ferment and distill the grain, with a second
    high energy budget. This usually means that you have a net energy loss,
    and unless you intend the output for recreational beverages, a net
    economic loss. Presently government subsidies offset the economic
    losses of the producers...

    For methane and bio-diesel, it is basically a one step process. Just
    let the micobes operate for methane, and capture the output, and just
    crush and extract the oils for bio-diesel. The methane route is used,
    because it involves waste products that need to be processed anyway.
    For bio-diesel, it is economically efficient for small users (using
    waste products, again...) but is not quite ready yet for large scale
    production. Petroleum at the well head is still too much cheaper...
     
  20. Not even wrong.

    Read any of the metalloradicals papers.

    One link in http://www.tinaja.com/glib/energfun.pdf


    --
    Many thanks,

    Don Lancaster
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    voice: (928)428-4073 email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
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