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Air Car

Post in 'The Green Room' started by Grapenut, May 21, 2008.

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  1. Grapenut

    Grapenut Member

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  2. Redox

    Redox Minister of Fire

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    Wishful thinking, IMHO. All it's doing is storing up the energy in the compressed air to use in the car sort of like a non chemical battery. You would still have to run a compressor to make the pressure. It probably isn't any more efficient than a battery operated electric car after all the losses are figured in. Also figure in the thousands of dollars (or Francs) to buy and maintain the compressor and I don't think it will make economic sense unless electricity were to become really cheap (not happening anytime soon).

    Chris
  3. Telco

    Telco New Member

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    Wishful thinking for a concept, less than wishful if they plan to start selling them this year. And, 1000 miles on a fillup, it's not going to take more than 10 bucks worth of electricity to fill that tank, if that, making it cost a penny per mile to operate. I could drive to work and back for more than a month on a single fill. And a 96MPH top speed? Outstanding. That's far enough and fast enough that I could use the car as my exclusive transportation, unlike the electric vehicle I was looking at where I could run around locally on electricity but would have to get a gasser for long distance driving. With that kind of range and recharge time, you could drive about 10-12 hours on a long trip, then recharge at the hotel provided there was an on-board compressor, or a way to take the compressor along, and let the hotel pay for your "fuel".

    Still, I'll be waiting to see how well they work out for other people before looking at one to buy. I know the wife wouldn't like it because she's scared of small cars, but it wouldn't bother me at all to eliminate about 30 percent of my gas bill per month.

    My main concern, how well would that air tank survive an accident?
  4. smirnov3

    smirnov3 Feeling the Heat

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    I am wondering how much of the performance of the air car & other 'miracle milage' cars comes from them being made from extremely low weight composites / plastics instead of steel?

    my father had an experimental Oldsmobile that was made out of fiberglass. a truck rear-ended him as he was pulling off the highway.

    the collision was so mild, he almost didn't feel it, but the whole rear of the car was totaled. But I'm guessing that modern composites do a better job of distributing the energy during a collision

    The main problem with composite cars is that the EPA mandates that some high percentage (I forget what it is) of any car sold in the USA be recycleable after the car is thrown out. Composites are not recycleable after about 3 years with our current recycling infrastructure.
  5. mikeathens

    mikeathens New Member

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    A friend emailed me a link to another promising one...

    http://www.aptera.com/about.php

    I think this and the "air car" both have a lot of potential. Just gotta "think outside the box"
  6. rowerwet

    rowerwet Minister of Fire

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    My main concern, how well would that air tank survive an accident?
    if you go to this companies website you find out that airbus is making the air tanks, they are a kevlar wound type of construction that is use in aircraft, when they are crushed/ struck hard enough to break, the kevlar (or other ) strands come unglued (think of a coconut shell) and the compressed air is released instantly in every direction. this keeps the "explosion" very low pressure and you don't get the shards of steel shooting into things the way a steel tank will.
  7. rhetoric

    rhetoric Member

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    If the tanks were made of metal, it would be shrapnel, but they claim the carbon fiber will just split. A REALLY lound bang, but only your eardrums would die.

    I guess while I know batteries are more efficient than air at storing energy (that is, there is alot of wasted heat energy in the production of compressed air), batteries are WAY more expensive than a tank or a compressor. And a tank isn't going to get old, lose storage capacity, destroy the environment with manufactured or disposed, etc. etc. etc.
  8. smokinj

    smokinj Minister of Fire

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    There is a small comany in Mexico making some compress air cars.Who knows what we will be driving in the next 25 years!
  9. Dune

    Dune Minister of Fire

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    If this car can achieve even half of it's projected 848 mile range, it will certainly be able to fill a niche here in this country, where the average car is driven 30 miles a day. The chasis is aluminum and the body fiberglass (seen plenty of 50 year old corvetts), with the main use of composites limited to the air tank. One problem that does occur to me is that 4500 psi air compressor. That component souds potentialy expensive to replace, and compressing air to that pressure obviosly requires a bit of energy. Great concept, can't wait to see it . And it would be truly great if it were affordable.
  10. Redox

    Redox Minister of Fire

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    I have never seen a pressure cylinder that wouldn't fail explosively, creating a lot of destruction when it happens.

    We have a client that makes various composite tanks for applications ranging from paintball guns up to mil-spec tanks for aircraft. All of them have a thin aluminum bottle that is wound with Kevlar, carbon fiber or fiberglass. Part of the manufacturing process is to test a sample of every production run to failure in a thick steel "bomb". It depends on the spec, but generally they fail at about 2X design pressure. In sounds like a relatively insignificant "pop" when it happens inside the bomb, but the result is a big shredded mess. You don't really want to be around one when it goes off. Even fiber is going to go right through a body at the speed these things fail at.

    High pressure cylinders definitely do have a service life and usually an inspection protocol as well. The cylinders in CNG service have a 15 year lifespan and are supposed to be visually inspected every 2-3 years, IIRC. Some cylinders also have to undergo a hydrostatic test periodically and they will eventually fail the test and are taken out of service. High pressure gasses are nothing to be taken lightly.

    I still don't believe that anyone is going to get that kind of range out of a tank of compressed air. The compressors used for high pressure applications are huge multi-stage affairs that require a lot of maintenance. Their efficiency is not very good due to all the friction losses in the compressor and rebuilds are very expensive. Overall, I think a battery has a greater long term usefulness.

    Chris
  11. whenley

    whenley Member

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    I would be worried about the temperature problem. Compressing a gas increases the temperature of the gas. 4000psi (about 300bar) would cause a VERY significant temperature increase, T2=T1*(P2/P1), a lot of cooling would be necessary. Also note, the temperature is waste heat - inefficient. Likewise, when the compressed air is allowed to expand into the air engine, it cools and you would soon have a lump of ice at the discharge nozzle.

    Also, the energy density of compressed air is quite low. 10cuft of air at 4000psi only contains about 14kWh of energy, thats equivalent to less than 1/2 gal of petrol.

    Wishful thinking indeed, I am not holding my breath waiting for the air car.
  12. Adios Pantalones

    Adios Pantalones Minister of Fire

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    There are expanding metal mesh materials that have been shown to reduce explosive hazards from gas tanks- they should greatly reduce any hazard from exploding air tanks.

    My concern is emissions- with all that air coming out- we'll surely be crushed by the pressure :)
  13. Valhalla

    Valhalla Minister of Fire

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    Come on, we may see this as strange today, but the future is wide open for electric, air and hydrogen powered vehicles.

    When automobiles were first "invented" there was no infrastructure for gasoline distribution. One could only buy it in a drug store. So this Indian/French company for the compressed air powered, GM for the Chevy electric Volt and BMW for their Hydrogen 7 have a wide open opportunity for new, alternative, and most importantly renewable fuels.

    Fill it up with H, please!
  14. velvetfoot

    velvetfoot Minister of Fire

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    Sound very interesting. Does it recharge the tank on the downhill runs, like a hybrid electric?
    You still need electricity to power this and the electric car and I image to produce the hydrogen for other alternatives.
    Most of these cars will be charged off peak, (commuters), so that would be a good thing.
    Electricity is key.
  15. Valhalla

    Valhalla Minister of Fire

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    Regeneration is usually only on electric or hybrid electric vehicles, also some current smart designs that charge batteries only when coasting, decelerating, etc. The alternator never loads the engine. BMW has it on some European models to reduce carbon / CO2 emissions and save fuel.

    Yes, we will see big changes in what we drive and how it is powered in the coming years. An open mind to change away from the typical gasoline powered vehicle is all that is necessary.

    Electric from wind and solar. Hydrogen to replace gasoline. It will be very interesting.
  16. karl

    karl Minister of Fire

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    Anybody that has used air tools knows that all these claims about efficiency are tough to swallow. I have a 3.5 horsepower air compressor and it barley keeps up with an air sander. My electric grinding wheel is probably less than a 1/4 horsepower and it does a better job with sandpaper on it than the air one. I have always thought of air as a wasteful store of energy.
  17. Valhalla

    Valhalla Minister of Fire

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    Air powered tools are relatively inefficient use of an air supply, and with very low pressure and high lost energy. I am not an expert in this or any air powered vehicle, however in my previous position I researched the basics of this city car, light weight design from the French and Indian companies. Air has a zero polution advantage like that of hydrogen, used in the BMW Hydrogen 7.

    Please see and paste the link:

    http://www.bmw.com/com/en/insights/technology/cleanenergy/phase_2/cleanenergy.html?language=1

    Our future energy needs will clearly be fueled by something other than petroleum, so electric, hydrogen and biofuel will be in our storage "tank" in the years to come. Solar and wind will assist in the production of these renewable fuels.

    Thanks.
  18. Adios Pantalones

    Adios Pantalones Minister of Fire

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    It's not a fuel source- it's a storage medium. There's no free lunch, but if it's a more efficient use, with less battery pollution concerns, then maybe it's wise to consider replacing some gas fueled cars with it.
  19. mikeathens

    mikeathens New Member

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    An open mind on all of this is a must...I would bet that these guys developing this aren't a bunch of morons. If they find it worthwhile to pursue, then it's probably a viable technology...despite any doubt that the application of simple ideal gas laws and thermodynamics might provide. If that's all there was to it, then this thing would have been dead in the water within days of the initial concept.

    If it ends up being a bust, then so be it. We as a country (or the world, for that matter) won't be out anything if it is a failure, but we will at least know that this isn't the way to go. Right? I, for one, believe that if they can achieve a 100 mpg fuel economy gasoline equivalent, it would be a HUGE success.
  20. Adios Pantalones

    Adios Pantalones Minister of Fire

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    Mike- yes and no- the guy with that hydrogen generator in his garage gets a lot of funding, but it's not the magic fuel that they report in the media. It is, again- a storage medium. You can get funding for lots of neat stuff, but that someone is doing the research does not imply practical application as funding is usually menat to boost a capability against one (usually esoteric and military) need.
  21. tkirk22

    tkirk22 New Member

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    [quote author="Mike from Athens" date="1221155611"]An open mind on all of this is a must...I would bet that these guys developing this aren't a bunch of morons. If they find it worthwhile to pursue, then it's probably a viable technology...despite any doubt that the application of simple ideal gas laws and thermodynamics might provide. If that's all there was to it, then this thing would have been dead in the water within days of the initial concept.
  22. Valhalla

    Valhalla Minister of Fire

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    We certainly show the passion and interest in the fuels of future, but we also share the common bond of burning wood, mankind's fuel for thousands of years.

    What will come when the petroleum is totally overpriced to run a chain saw? Will electric take over? Or we just use an ethanol (biofuel mix) mix? A biodiesel chain saw? It will be interesting.

    Hey, do the chain saws in Brazil run on their 100% hydrous ethanol? Special materials are needed if they do.
  23. mikeathens

    mikeathens New Member

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    I'm not disagreeing with this...it's a huge posibility. Just like it is with "proven" major mortgage companies or investment firms. Greed is human nature for the majority. I'm just saying that this is a technology that could work out. This is either a case of someone trying something new with initial design showing promise, or, as you say, a complete deception.

    I'd rather believe in something like this than new coal-fired power plants and expanded off-shore drilling. Talk about greed...
  24. BobTheTomato

    BobTheTomato Member

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    The one promising thing I see about this is that it is not getting huge amounts of goverment funding (from what I can tell) like ethanol. It seems several different companies are trying to make the engine/storage medium of the future. May the best company win.
  25. kenny chaos

    kenny chaos Minister of Fire

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    I'm guessing the level of technology used here is more along the lines of what's used in dental equipment versus shop mechanics tools.
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