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Thread: Methanol Fuel Cells on the Battlefield.

  1. #1 Methanol Fuel Cells on the Battlefield. 
    Time Lord
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    Apparently methanol, has about 15 times the energy storage density of a lithium ion battery of the same size. That might be limited by inefficiencies inside the fuel cell used to reconvert it back into electricity, wherein some of the methanol gets lost by oxidizing. The exhaust output is just CO2 and water.

    http://en.wikipedia.org/wiki/Direct_methanol_fuel_cell
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    One of the fuel cell's inventors, George Olah mentioned in passing during an interview that the process is reversible, so electricity can be used to create methanol from CO2 and Water again. That would mean that a military base with access to some other power source, like solar panels, would be able to create more of it on the spot with the right equipment.

    The Methanol Economy - Technology Review..

    Do you think this might be the pathway that ultimately leads to getting powered armor suits onto the battlefield? No need for a power cord if you're actually carrying a sufficient amount of electrical energy with you. And recharging gets replaced by refueling. The tech is even usable indoors. Micro fuel cells that utilize it are currently permitted on airplanes.

    Direct methanol fuel cell - Wikipedia, the free encyclopedia


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  3. #2  
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    i read through some of the links you posted. the current technology maxes out at an output of 5 kilowatts for 100 hours. now, 100 hours seems like good specs for operation of an armor suit. however, compared to the energy output in Mj/Kg, methanol comes up short against many other compounds such as crude oil, gasoline, hydrogen, and quite a few other high-energy molecules, listed here: Energy density - Wikipedia, the free encyclopedia


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    What's the size of the fuel cell equipment? I have no doubt a gas engine and generator might get more from the fuel, but it would probably add another 50-100 pounds. It would also be noisy.
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  5. #4  
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    Quote Originally Posted by saul View Post
    however, compared to the energy output in Mj/Kg, methanol comes up short against many other compounds such as crude oil, gasoline, hydrogen, and quite a few other high-energy molecules, listed here: Energy density - Wikipedia, the free encyclopedia
    Hydrogen has excellent energy density by mass, but horrible energy density by volume, which is probably a bigger issue in a battle armor suit. Methanol has just under half the energy density by volume of gasoline, so it doesn't win that competition (15.6 MJ/L vs. 34.2 MJ/L). If it's used to power an automobile, it will only have about half the range, although it still works in ordinary gasoline engines.

    Quote Originally Posted by wiki methanol fuel article
    Internal combustion engine fuel

    Both methanol and ethanol burn at lower temperatures than gasoline, and both are less volatile, making engine starting in cold weather more difficult. Using methanol as a fuel in spark ignition engines can offer an increased thermal efficiency and increased power output (as compared to gasoline) due to its high octane rating (114[8]) and high heat of vaporization. However, its low energy content of 19.7 MJ/kg and stoichiometric air fuel ratio of 6.42:1 mean that fuel consumption (on volume or mass basis) will be higher than hydrocarbon fuels. The extra water produced also makes the charge rather wet (similar to hydrogen/oxygen combustion engines) and combined with the formation of acidic products during combustion, the wearing of valves, valve seats and cylinder might be higher than with hydrocarbon burning. Certain additives may be added to the fuel in order to neutralize these acids.
    Methanol, just like ethanol, contains soluble and insoluble contaminants.[9] These soluble contaminants, halide ions such as chloride ions, have a large effect on the corrosivity of alcohol fuels. Halide ions increase corrosion in two ways; they chemically attack passivating oxide films on several metals causing pitting corrosion, and they increase the conductivity of the fuel. Increased electrical conductivity promotes electric, galvanic, and ordinary corrosion in the fuel system. Soluble contaminants, such as aluminum hydroxide, itself a product of corrosion by halide ions, clog the fuel system over time.
    Methanol is hygroscopic, meaning it will absorb water vapor directly from the atmosphere.[5] Because absorbed water dilutes the fuel value of the methanol (although, it suppresses engine knock), and may cause phase separation of methanol-gasoline blends, containers of methanol fuels must be kept tightly sealed.
    Methanol fuel - Wikipedia, the free encyclopedia

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    robably not a good idea to run an engine off of the same mix that you'd run a fuel cell off of, though, unless you need to in a pinch. (Better to put some wear on the engine than have the whole vehicle get shot up.)
    Last edited by kojax; August 23rd, 2011 at 07:19 AM.
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    Quote Originally Posted by kojax View Post
    Probably not a good idea to run an engine off of the same mix that you'd run a fuel cell off of, though, unless you need to in a pinch. (Better to put some wear on the engine than have the whole vehicle get shot up.)
    Perhaps I didn't explain well enough. Energy density in terms of volume and mass isn't a complete picture. We also need to consider the size and weight of the equipment to extract that energy. Are fuel cells lighter and smaller than internal combustion engines coupled to a generator? If they are, is it enough to compensate for the lower energy density of the fuel?
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  7. #6  
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    I think depends how much power output you need. If it's just for small objects, like laptops and stuff like that, it can get pretty small.



    That's Samsung's DMFC 1800 kw/h model being made for the US Army. I can't seem to find good specs for its instantaneous output, but it weighs 3.5 kg and supposedly has as much electricity as between 8 and 10 kg of batteries would have, including the converter. A lot of sites come up if you google Samsung DMFC 1800, but I couldn't seem to find any that gave more detail than that. I really would like to know how strong it is, so as to get a picture of how many of those would need to be chained together to make a power suit work.


    Samsung's latest fuel cell prototype proves again that soldiers get the coolest toys -- Engadget,
    TECH NEWS: IT & TECHNOLOGY - DMFC battery from Samsung,

    The big problem with Direct Methanol Fuel Cells (DMFC) is they use platinum, which is a very precious metal. You would not want to leave disabled DMFC's on the battle field, no matter how destroyed they get.
    Last edited by kojax; August 23rd, 2011 at 05:56 PM.
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    Quote Originally Posted by kojax View Post
    That's Samsung's DMFC 1800 kw/h model being made for the US Army. I can't seem to find good specs for its instantaneous output, but it weighs 3.5 kg and supposedly has as much electricity as between 8 and 10 kg of batteries would have, including the converter.
    I'm thinking the units are 1800 watt-hours. But that's pretty impressive. Assuming it would take an hour to discharge the cell, a small gas engine-generator set of about the same output weighs about 20 kg, make a lot more noise and perhaps heat. And it appears you can quickly refill these fuel cells with more water and methanol.
    Last edited by Lynx_Fox; August 24th, 2011 at 09:41 AM.
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  9. #8  
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    Yeah, I totally got that wrong. It is just 1800 Watt hours. I guess 1.8 kwh didn't sound cool enough for the marketing brochures.

    Even more than its tactical value, it would probably be really good PR if the military were to spearhead research into this. Then they'd have another talking point when it came time to justify their budget to Congress or the public in general. If they were able to improve the cell technology, or make it more ready for mass production, they could tack it onto their list as another benefit that has come out of the war.
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  10. #9  
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    Power suits sound like a good idea but they would be, like every other piece of equipment on the battlefield, maintenance magnets. Technology is cool but it only matters in firepower. Everything else is merely a way to get firepower to the battlefield and the more you need to get there, the more you need to use to get there.

    Currently, there are 8 service or administrative personnel for every combat soldier. S1,2,3,4 are all clerks, medics, mechanics, etc.

    The more moving parts a machine has, the more things can go wrong. The infantryman's perfect tool is the cyalume chem light. It has no moving parts and you have to break it to make it work.
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  11. #10  
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    The more moving parts a machine has, the more things can go wrong. The infantryman's perfect tool is the cyalume chem light. It has no moving parts and you have to break it to make it work.
    RFOL. Never heard that before.
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