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Power Hardware Science

Self-Sustaining Solar Reactor Creates Clean Hydrogen 406

An anonymous reader writes "A mechanical engineer working out of the University of Delaware has come up with a way to produce hydrogen without any undesirable emissions such as carbon dioxide. The solar reactor is capable of using sunlight to increase the heat inside its cylindrical structure above 3,000 degrees Fahrenheit. Zinc oxide powder is then gravity fed through 15 hoppers into the ceramic interior where it converts to a zinc vapor. At that point the vapor is reacted with water separately, which in turn produces hydrogen. If the prototype gets through 6 weeks of testing at the Swiss Federal Institute of Technology located in Zurich, we could see it scaled up to industrial size, producing emission-free hydrogen."
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Self-Sustaining Solar Reactor Creates Clean Hydrogen

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  • by sirlark ( 1676276 ) on Wednesday April 04, 2012 @06:54PM (#39579065)
    Could it effectively be mass produced so that it could become a household item, every house having it's own hydrogen generator and turbine which can contribute to the grid? I've always thought that decentralising power production would make it greener, if only because there's less loss to long distance transmission. Either way, I'm holding thumbs for the six week trial.
  • by DigiShaman ( 671371 ) on Wednesday April 04, 2012 @07:01PM (#39579165) Homepage

    But is mining for zinc just as clean? I know you have to start somewhere. Just thought I'd throw that out there for discussion sake.

  • by MachDelta ( 704883 ) on Wednesday April 04, 2012 @07:02PM (#39579187)

    It seems to me that as an energy storage medium (and that's what it is, it's not a fuel "source") Hydrogen would lose out to a plain old chemical battery when all it needs to do is sit in your basement. One of the primary pitfalls of a battery is weight and size, but that won't much matter if you just dig a deeper hole in the ground and never move it.
    Anyways, going Solar -> Hydrogen -> Electrical sounds a lot more complected (not to mention inefficient) than just Solar -> Electrical.

  • by jiteo ( 964572 ) on Wednesday April 04, 2012 @07:02PM (#39579193)
    How do you produce the zinc oxide powder? How do you produce the cylindrical structure? Not trolling, genuinly asking. If someone with more metallurgical knowledge than me tells me zinc oxide is common and easy to mine, I'll believe it. But it's a question we must ask.
  • by icebike ( 68054 ) * on Wednesday April 04, 2012 @07:13PM (#39579339)

    Clean in this context probably refers to not requiring fossil fuels.

    Apparently the Zink Oxide is recoverable as well:

    As well as a lack of emissions, the other good news is that the zinc oxide can apparently be reused, meaning the solar reactor is theoretically self sustaining as it only relies on materials and energy that are renewable.

    although it isn't spelled out how that is performed, or if any processing is required, and if so, at what cost.

    To heck with scaling this up. Lets scale it down so I can have one in my back yard, or at every corner gas station. A small reactors working any time there is sunlight and water scaled just large enough to keep your car topped off makes a lot more sense than trucking hydrogen around. Especially if the zink oxide recovery can be built in.

    Then maybe hydrogen cars can become a realistic option rather than the proof of concept models and conversion kits for fleet vehicles.

  • by Fluffeh ( 1273756 ) on Wednesday April 04, 2012 @07:14PM (#39579347)

    Hydrogen stored under pressure has a considerably lower energy density compared to hydrocarbons that we use. Hydrogen is great when you look at the energy by weight, but if a tank is sitting in the back of a car, it doesn't matter whether it weighs an extra twenty kilos, what matters is how far a tank can make a car drive.

    Like I said, don't get me wrong, I think it is a fantastic breakthrough to have - a cheap, clean and sustainable way to make Hydrogen gas, but a lot of work still needs to be done before we can all whizz around in clean cars and certainly before we have large scale power stations powered by burning Hydrogen.

    Having said that, burning Hydrogen makes water, this process turns water into Hydrogen. It would make for a wonderful closed circuit...

  • by Anonymous Coward on Wednesday April 04, 2012 @07:42PM (#39579647)

    it can be stored in vast quantities in the form of formic acid and then released and restored in a continual cycle. there is obviously efficiency losses but apparently its very practical as it allow storage of large amount of hydrogen at a very high density in a room temperature atmospheric pressure liquid,
    that is basically as safe as vinegar.

    I was thinking this clean hydrogen would be perfect in so many parts of the world where their is plenty of sunlight but the land is otherwise of low value.

    ps: its the nail polish like odor that gets released when ants die, and more specifically when they get crushed. its probably something they are sensitive to, so hopefully our green cars in the future dont get covered with ants in because of the pheromone.

  • by Solandri ( 704621 ) on Wednesday April 04, 2012 @08:06PM (#39579857)

    One reason storing it is such a big deal is because generating it can be expensive. Make hydrogen easier to produce and it lowers the demands on storage.

    Eh? Those have nothing to do with each other. Hydrogen storage is a pain because of density and sealing. At STP, hydrogen is a very low density gas. To get decent energy density out of it, you either have to compress it to ridiculously high pressures, or chill it to ridiculously low temperatures. Di-atomic hydrogen gas molecules are about the smallest molecules that exist. They will leak through anything. A seal which is water-tight and air-tight is not necessarily hydrogen-tight. Couple this with high pressures and you have a major storage PITA.

    Unless we discover some sort of hydrogen sponge which soaks up H2 gas and easily holds it at an energy density competitive with batteries and chemicals, I really doubt the hydrogen economy will take off. OTOH if someone can tweak this process so it can convert CO2 + 2 H2O ==> CH4 + 2 O2, then we have a winner. Methane, while not as ideal for storage as a liquid hydrocarbon (most oil wells and refineries just burn it off rather than try to capture and store it), is much easier to work with than H2 gas and has nearly 4x the volumetric energy density.

    Long-term, I think alcohol biofuels will win out. Alcohol is nearly as good a storage medium as gasoline/diesel. First you use photosynthesis to create sugar: CO2 + H2O + sunlight ==> O2 + (CH2O)n. Plants are basically made of really long sugar molecules (cellulose). You then ferment the sugar to create alcohol: (CH2O)n ==> C(n)H(2n+1)OH. At some point we'll probably figure out a way to go straight from the raw ingredients (CO2 + H2O + sunlight) to alcohol, at which point you're converting solar energy straight into liquid fuel.

  • by TheInternetGuy ( 2006682 ) on Wednesday April 04, 2012 @08:07PM (#39579867)

    Or even use the hydrogen in a Carbon-monoxide/dioxide capture scheme and produce methanol that could be used in today's engines with minor conversions.
    The cars would of course re release that carbon dioxide when driving, so it wouldn't really be sequestering.

    See syn-gas to methanol process from the 1920's by Alwin Mittasch and Mathias Pier. Or alternatively the newer processes involving a copper catalyst.

  • by mellon ( 7048 ) on Wednesday April 04, 2012 @08:45PM (#39580167) Homepage

    You can melt steel with a 10' mirror. You can't melt *much* steel, but getting high temperatures isn't a problem; the question is whether the yield is enough per square meter of mirror to be worth it, and whether it scales up to higher efficiencies as you increase the area of the mirror and the size of the reactor vessel.

  • by peragrin ( 659227 ) on Wednesday April 04, 2012 @09:39PM (#39580553)

    coal is very easy to move around, all you need is a bucket big enough.

    Hydrogen is very hard to move around under pressure. as one of the other ./'ers aid like trying to hold water in a strainer.

    Even Gasoline is relatively easy to transport.

  • by ThreeKelvin ( 2024342 ) on Wednesday April 04, 2012 @09:59PM (#39580679)
    But why would you build a power plant like that?

    You're proposing a cycle that goes something like:
    solar mirrors -> zinc reactor -> hydrogen furnace -> turbine

    Why not just use the old and tried method of:
    solar mirrors -> hot steam -> turbine

    It would be simpler and far more efficient.

    Now, the story is interesting because it's about creating hydrogen using sunlight, without converting the sunlight to electricity first.
  • by dbIII ( 701233 ) on Wednesday April 04, 2012 @10:26PM (#39580797)
    A lot of fertilizer (ammonium nitrate) is made from oil or natural gas purely because that's the easiest way to get hydrogen. There are a lot of other industrial uses for hydrogen which currently mean chemical plants are close to oil refineries and natural gas pipelines.
    As a fuel hydrogen gas is a pain to store and transport in comparison to butane, propane etc or a liquid fuel, but if you can make it at sane costs where you need it then you don't need to store or transport much of it.
  • by Mindcontrolled ( 1388007 ) on Thursday April 05, 2012 @04:48AM (#39582447)
    Please, could we stop that hydrogen embrittlement nonsense? That stuff came up about a year ago in some slashdot discussion and subsequently has been parroted over and over again. Hydrogen embrittlement happens at high temperatures, i.e. when you get hydrogen to diffuse into your steel while forming it, in a glowing hot state (as you can read in your own link). At room temperature, it is negligible. I used to work in a lab with a hydrogen installation for years - not like it crumbled under our hands.
  • by SplashMyBandit ( 1543257 ) on Thursday April 05, 2012 @05:41AM (#39582587)
    Yeah. Just as well I did a fair chunk of thermodynamics during the undergraduate and honours year levels before my PhD in (astro)physics. I'm really amazed that people in the US still cling to their archaic system and rush to its defense when the rational thing to to interoperate with the *rest of the World* (and, as I pointed out, their own military who apparently is more progressive than you, lol). I fully understand the Fahrenheit units but I'm amazed people would try desire them for any other reason than they just like old traditions. Bizarre.

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