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generation of electricity through compressed air

Discussion in 'Alternative Energy' started by hotshot, Feb 22, 2009.

  1. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    The motor is not the bottle neck in the air power concept. The pressure limits of the storage tanks VS their size and weight is what the problem.
    DO the math on what a air tank that could power the average sized vehicle the same distance as the fuel in its gas tank produces.

    How do you fit a 10,000 PSI 20 ton semi tanker in the trunk of an average car?

    And what power source pumps it up to start with? All of that energy has to come from some place to start with and those starting places and equipment to capture that energy are never free even if the energy source is.
     
  2. gingerground

    gingerground New Member

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    tcmtech has miised some important elements. ASide from trying to conceptualise the average car, tech seems to assume that efficiency and size are synonymous. The average sized gas powered car could never be the same as the average air powered car.

    Further, as I have said, there is the mechanically competent source of electricity that neither tech nor the rest of the world will see if there is no chance of my making money.

    Tech must understand that the laws of physics, set as they are can be mainpulated- if you truly understand them.

    Yes, the equipment is never free but its simplicity renders cost a non-factor and yes, the energy and the air will be that cheap- multiplied by 3, 5 or 20 million units.


    Once the size of the car has been established, the cheapness of the air will no longer be an issue- 20 ton semi- HA!!! But existing car makers are so wedded to their old technology, they will never see the virue of something else.

    Interestingly, tech has ignored the SCAm and the other issues raised by me- how convenient.


    Clive
     
  3. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Huh? Size of the car establishes the cheapness of the air?

    Okay then do the math for me. My car seats four comfortably, weighs 4000 pounds and goes on average 350 miles between fuel ups at 75 MPH and can pull 4000 pounds at 75 MPH for at least 250 miles as well.
    Also factor one out for a 40 ton semi that goes 500 miles at 75 MPH between fill ups as well.


    Match those vehicles range and power with air power for the exact same average numbers. Then tell me what size of air tank and at what pressure it has to run at to be equivalent to the fuel they use doing that work.
    I and probably a few others would like to see your numbers on horsepower, air tank capacity, and tank working pressures for both cases.

    Plus some tips on how you "manipulate the laws of physics" as well would be great too.

    I find these to both typical and realistic and nessisary vehicle choices I come across every day in my life.
     
  4. dave

    Dave New Member

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  5. mavrick

    mavrick New Member

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    What if we have a free source of compressed air?

    Hi Everyone

    I am doing an internship at a company which make compressors.So when they are run in the test stands,the compressed air is just let go into the atmosphere.We make a range compressors from 100 hp ones 6000 hp ones.All this while I was looking at only waste heat recovery methods(like ORC) that could possibly implemented in our test stands.I wasn't sure whether compressed air can be directly used to run turbines.If so please enlighten me on that.Thanks in advance
     
  6. Thunderchild

    Thunderchild New Member

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    sure you can run a turbine on compressed air and turn a generator, it would get you more power back than just the heat recovery
     
  7. peufeu

    peufeu New Member

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    Your car is a truck, man.

    Since I'm french, let me say that in france we aim to take over the world with the compressed air car. Some guy founded a society named MDI to market it. Check it out in google, it exists, they even have a working prototype. Of course I can outrun it with my bicycle but that isn't the point right ? it's ENVIRONMENTALLY CONSCIOUS.

    I used to think that only the russians can pull this off but look at how far we've gone.

    Of course, the basic facts of physics mean that the car itself is ****, and needs to be recharged in compressed air about every 5 minutes (sorry, thermodynamics is a *****) at a compressed air service station that doesn't exist.

    However in France we have the world monopoly of politicians hot air manufacture, so this may work, who knows. A good thing about a compressed air car is that you get free air conditioning, courtesy of adiabatic decompression. This may work in Texas (although the compressed air car would be heavier than a couple average texans) or florida, but not france, where opening the windows suffices to get the temperature back to normal.

    So, until now, we heard about this technology on the news but you can't buy it yet, go wonder, maybe it's because it has no advantage whatsoever over the good old internal combustion engine, who am I to tell.

    > wasn't sure whether compressed air can be directly used to run turbines

    Yes it can, you can run a turbine on anything that has enough pressure differential to ambient : steam, fossile fuel, compressed air, etc. Of course, if you mean to use a compressed air tank as a battery, lithium will beat you about 100% of the time.

    > One question? WHY DOESN'T THE US GOvernment enlighten the rest of us about its silent submarines and stealth aircraft-

    Yeah good question. I have a stealth bicycle ! You think DoD's interested in this ? If so, send me a mail via my nigerian account.

    > We can smell over unity and free energy scam's miles away

    Yep.

    > The AIR CAR IS VERY Possible and could cost US$25 a month for the air
    > supply, no matter how far you drive, air will not cost any more for a whole mont.

    Yeah air is free which is why politicians can move so much hot air around without concern. Energy isn't free however, because thermodynamics is more badass than socialism. I can build you an air car that goes 100000 mpg, if the wind blows in the right direction. It will even go on water. I think it's called a sail boat. You may need to row, though, if you run out of air. That's always been the problem with free stuff : when u get the bill.

    And by the way, a pedal generator with a 2007 Lance Armstrong on it will yield about 500W, with an average bureaucrat it would yield about 80W.

    I'm mostly using the bicycle as a means of transportation because I live in a city and can't be bothered to spend 15 minutes to find a space to park my car. I've run some calculations on eco-leftist carbon footprint websites, and it turns out that with modern fossil fuel dependent agriculture, the energy you expend on a bicycle, or any other kind of exercise, coming from food, coming ultimately from oil, has a rather high carbon footprint. Fortunately, I am not an eco-leftie, so I dont care. But it is a fact that energy from human muscle consumes more fossil fuel than using said fossil fuel directly in an engine.

    Thanks for this thread.
     
    Last edited: Oct 15, 2010
  8. mavrick

    mavrick New Member

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    Thanks Thunderchild.I am not sure about the factors that will come into play in choosing a turbine.I know pressure and temperature will be the major factors.But is there any other factors that I should consider?

    Thanks
     
  9. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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  10. Thunderchild

    Thunderchild New Member

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    I have no idea
     
  11. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    So the long and short of this thread so far is that air power is only cheap, reliable, and practical if the energy source for pumping up the air tanks is not factored in, and the size of the tank and the pressures required to compete with any real world real life driving or work comparable to what standard vehicle fuels do even with dismal efficency ratios is not factored in, plus the reality of the physical aspects of the vehicle are left out as well. :(

    Hmm, this does seem almost practical when the reality of real life physics and working requirements are not part of the equations! :rolleyes:
     
    Last edited: Oct 27, 2010
  12. peufeu

    peufeu New Member

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    Here you can see the French compressed air car inventor/manufacturer :

    http://www.mdi.lu/english/index.php

    I must say that I am quite impressed by the efforts and dedication of this company.

    Please stop laughing at the suppository car in the video on the front page. I can probably outrun this on my bicycle, and the form factor (tricycle with 2 wheels on the back) means that it is anyway impossible to expect reasonable handling, like braking in a turn.

    Using 3 wheels (or 3.5 wheels) isn't a bad idea for a lightweight vehicle, of course you need to put the 2 directing wheels (widely spaced) on the front and one propulsion wheel at the rear (no differential). Like the Aptera, VW 1L, or my recumbent trike.

    This, gentlement, is a golf cart, and is meant to be driven like one (not jackass style).

    http://www.mdi.lu/english/miniflowair.php

    This one looks like a real car (albeit a very small one), it has decent maximum speed and range (which I will believe when I see it) but the most interesting thing in it is not the compressed air, it is in fact the low weight and general optimization which yield an excellent fuel consumption (less than 2L/100km). And the excellent trunk.

    These guys use their compressed air engine and feed it either with pure compressed air, or the output of some kind of reactor where the compressed air is mixed with gasoline and ignited. Pretty clever. Since it includes a compressor to replenish the compressed air tanks, I guess the logical evolution would be to get rid of the expensive, large, dangerous, and cumbersome tanks, and only keep this new evolution of the petrol engine (I guess it's an external combustion engine then...) which apparently has excellent characteristics

    Note : a VW Polo will do 3 L / 100 Km on the highway...
     
  13. Wayne Garland

    Wayne Garland New Member

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    Wayne

    I have an idea to create compressed air.

    You construct a giant dome which floats in the sea in water approx 4 metres deep (depends on the distance the tide goes in and out). The height of the dome would be the same height as the distance the tide goes in and out. The dome is fixed in place by poles so it can't float away however it can move up and down as it floats on the surface of the water (imagine giant ringlets on the edge of the dome which feed over the poles. At dead low tide the dome fixes in place by locking onto the poles. The tide then rises around and over the dome. At dead high tide there will be pressurised air under the dome (like when you carefully push an upside down cup into water and flip it over to see the air bubble float to the surface). The pressurised air can be released into a land based receiver vessel through a series of controlled valves. After the pressurised air is released the dome would unlock from the poles and float to the water surface with the aid of floatation devices attached to the dome. The air in the land based receiver can drive a turbine for electricity generation. The dome repeats its action with the daily rise and fall of the tides.

    I've registered this as an idea. Anyone think it could work?
     
  14. shortbus=

    shortbus= Well-Known Member

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    NO, not a chance
     
  15. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Works and works efficiently enough to pay for itself in any realistic time frame are too very different things. :(

    Air is just a over all poor medium to use for energy production other that directly by wind power simply due to the astronomical volumes required to make any practical levels of power.

    If you have an area with a 4 meter tide you would be much further ahead in the game to just put a simple earth dam across the bay area and use a low head bidirectional hydroelectric generation system instead. That is done in many places around the world and has proved itself to be practical and cost effective to build and operate. ;)
     
  16. pjl83

    pjl83 New Member

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    Going back to the original idea in this thread, what if the pads were in the floor of a busy shopping centre where people walk constantly all day, they are walking there anyway so the energy is free.

    One other thing, what if the pads had hydraulic fluid in rather than just air. Similar to how wave generators work in the sea. This would be more efficient maybe?
     
  17. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    This may prove educational. http://www.electro-tech-online.com/threads/piezo-electric-energy-harvesting-project.86072/:)
     
  18. aniphics

    aniphics New Member

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    Well guys , went through the posts, it is interesting. I also want to generate electricity by compressed air, yes the question is from where to get the compressed. I might be wrong but can we get a huge cylinder (like 20 feet long and 4 to 5 feet in diameter) size and diameter can vary, insert a real heavy stainless steel piston , place it vertically along the building and let gravity do its work. I believe when the piston falls it will produce enough compressed air to be stored in the storage tank underground. To take the piston back up we can use a gearbox with a slow motor. It can take few hours to raise the piston. Since the storage tank is underground the the temp around the tank shall be a bit higher than the compressed air in the tank, which will make the compressed air in the tank to expand and produce more pressure...

    Any suggestions guys...yes the measurements of the cylinder needs to worked out, so that it can produce enough compressed air in one , two or three falls in 6 to 12 hours....
     
  19. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Hi aniphics! Welcome to ETO :)

    Since you're new, I'll just politely point out that this thread is nine months old. Generally it is not a good idea to resurrect old threads, so keep that in mind for future reference ;)
    As for your question, I'd recommend you start a new thread, rather than adding on to this one. You will be more likely to get the answers you desire.

    Best regards,
    Der Strom
     

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