Posted on 05/25/2009 2:52:04 PM PDT by The_Sword_of_Groo
NEW YORK (AP) - Most car companies are racing to bring electric vehicles to the market. But one startup is skipping the high-tech electronics, making cars whose energy source is pulled literally out of thin air.
Zero Pollution Motors is trying to bring a car to U.S. roads by early 2011 that's powered by a combination of compressed air and a small conventional engine.
ZPM Chief Executive Shiva Vencat said the ultimate goal is a price tag between $18,000 and $20,000, fuel economy equivalent to 100 miles per gallon and a tailpipe that emits nothing but air at low enough speeds.
Elsewhere in the world, the technology is already gaining speed. The French startup Motor Development International, which licensed the technology to ZPM, unveiled a new air-powered car at the Geneva Auto Show in March. Airlines KLM and Air France are starting to test the bubble-shaped AirPod this month for use as transportation around airports.
Engineering experts, however, are skeptical of the technology, saying it is clouded by the caveat that compressing air is notoriously energy intensive.
"Air compressors are one of the least efficient machines to convert electricity to work," said Harold Kung, professor of chemical and biological engineering at Northwestern University. "Why not use the electricity directly, as in electric cars? From an energy utilization point of view, the compressed (air) car does not make sense."
As Vencat spells it out, the "air cars" plug into a wall outlet, allowing an on-board compressor to pressurize the car's air tank to 4,500 pounds per square inch. It takes about four hours to get the tank to full pressure, then the air is then released gradually to power the car's pistons.
(Excerpt) Read more at breitbart.com ...
Correction to an earlier comment! Sorry.
Using some type of acid bath into which you drop pellets when the pressure goes to low to run, right? builds up the 4500 PSI it needs and then in a runaway fit of chemical reaction blows the hell out of you and the car? That type of thing?
Alas, the memories....
I bet I have the finest XL250R vintage '82 though...
Good question.
There is a comment above suggesting containment of solidified gas (CO2) warmed to a gaseous phase change for the required pressure. But in the world environment of ambient temperature and pressure it would require big energy to separate and liquify the gas in the first place. Thermodynamically there would be no way to invoke that as an overall efficient driving mechanism. One is just displacing the required energy from the auto itself to the solidification site (even if it is onboard).
Your chemical reaction thought is scientifically deeper. The chemical reaction itself is controlled by the temperature and pressure under which it occurs, so as the overpressure and temperature change with the contained reaction so does its mass balance. There is such a thing as chemical potential, fugacity, peculiar to the individual reagents involved, so I think an analysis could be done depending on the reactants and the containment configuration.
It doesn't strike me at first that there is any fundamental thermodynamic reason (three laws) that there could not be a given reaction producing like what you are thinking. Of course it would also depend on the availability, volatility, artefact, conditions, etc. of the reactants wrt their origin.
But the big thing is if it were a clear case of intrinsically available reactants than the process would have been exploited anyway over the last few hundred years of industrial revolution.
The one profound aspect of this auto article is that pressure is every bit an accessible form of energy as heat. Pressure is energy per unit volume, so that available pressure difference, like between the ocean floor and the atmosphere, or between the containment and release chambers of this auto, is a viable source for human (negentropy) use. It's just a matter of getting the pressure difference in the first place,e.g. ICE.
Anyway, nice question, hopefully there will be other insights.
I’m pretty sure the 4,500 PSI is only for storage.
They probably regulate it down to run it in the air motor.
Just guessing anyway.
I like your answer to the chemical question far better than my attempt a humor answer. I have question for you: As you say, there is a pressure difference between the top of the ocean and the floor(depending on depth of course). Would there be a feasible way to use that pressure to build pressure in tanks and use it for energy converstion, for instance a deep water electricity generating plant?
FReeper Jnsun gave a far better answer, and a serious one, at post 63. You might want to take time to read it...
You need to power all the wheels to propel a locomotive because steel on steel is a very low coefficient of friction.
It’s easier to use a bunch of electric motors to do this than a complex mechanical drivetrain.
Sounds like something Baraq should spend our tax $$ on, LOL
Your joke was not lost ;-)
Your chemical reaction would only need a couple hundred PSI instead of 4,500.
Of course, if you are dropping calcium carbide into water, you don’t want anything over 15 PSI. (hehe)
Compressing air, as it is usually done, IS very inefficient. And it is no secret to anyone who has been around an air compressor why - you’re losing all that heat resulting from compression of the gas.
If (and it is a big ‘if’) you could capture that resulting heat and somehow store it in the system (let’s put aside the details of how just now), your efficiency goes up a fair bit.
Now, if you could store that heat as heat (rather than convert it into some other form of energy, with the attending losses) and re-introduce it into the air as you DE-compress it (which pulls in heat from the outside environment - ever been around a bottle of compressed air that is discharging rapidly? The tank gets cool, right?) you’d get more of your overall energy back in the compressed air on the way out of the tank.
So, once again, we come back to the thing which I harp upon in these “alternative energy, unicorn and skittles” threads here on FR — this is always a thermodynamics problem. These systems all come down to the same basic problems:
1. Converting the “alternative energy” (whether it be from wind turbines, wave action, solar power, or unicorn flatulence) and apply it to the problem at hand,
2. With the fewest number of conversions,
3. And while capturing as much of the wasted energy in the conversion process as possible.
Net:net — if we could capture the heat and re-introduce it on decompression, compressed air is actually a viable energy storage idea. It can sit there for a long doggone time without loss (unlike hydrogen storage, or batteries) it doesn’t require some fundamental new chemistry or chemical engineering, as all the promised super-batteries do, and it is possible to convert mechanical energy (say, from a wind turbine) to compressed air easily and cheaply. (eg, we could convert a big-block Chevy engine into an air compressor, hang a big-assed prop on it and wha-la, we have a big air compressor. Just stick it up into the wind in Wyoming and we have a whole lot of power.
Back to the storage problem: there’s work going on to store compressed air in salt caverns in order to harvest energy from wind power in a way that converts wind to a power source that we can schedule for base loads. Why there? Because they can use melted salt to store the heat quite nicely at the same time they’re using the cavern to store the pressurized gas. Just run the liquid salt through a heat exchanger as you’re pulling the compressed air out of the salt mine and you’ve got some big-scale power storage.
One little wrinkle: There’s never a salt mine where you need one.
But similar ideas are being used on portable compressed air storage systems — ie, capture the heat and re-use it on the expansion side. That’s where some nifty work is happening right now. I’m NOT saying this is a panacea or the solution to all our problems, but I will say this — I think that a compressed air vehicle makes more sense than these idiotic electric vehicle plans, mostly because we can store compressed air in large quantities distributed around the country better than we can store electrical power in the grid.
Oh, great! Now we’ll have an air shortage. Al Gore will demand a air tax and we’ll all have to get measured to determine our air footprints. I just can’t wait.
Are you sure? Air contains some CO2...
Here is a very cool electric car with a motor on each wheel It does 400 kph and out drags a Porsche. The CEO of Mitsubishi was awed when it beat the best he could offer. There are a series of very very neat videos describing how this amazing car was built by university researchers with no car building experience.
http://telstarlogistics.typepad.com/telstarlogistics/2009/01/japanese-electric-car-has-eight-weels-big-ambitions.html
Another advantage is dynamic braking where the motors now generate current that is wasted through a heater grid and fan in the roof of the locomotive. Have you ever noticed the diesels taking a load and the fans spinning up as a train arrives. Why are the diesels producing poweras the train slows? It's because the generators are exciting the fields of the motors causing the armatures to convert rotation to current that heats the grids and causes the fans to spin. It saves the airbrakes, and is a safety feature on long descents.
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Hybrids aren't diesel because diesel power is heavier and more expensive - undesireble in an already heavy and expensive vehicle. There are also costs for soundproofing the noisy contraptions.
Thanks, I am familiar with regenerative braking. I know I sounded very ignorant in my original comment, and I am no engineer but do have some knowledge and I deeply appreciate your answer. I realize diesel engines are heavy but it seems to me that hybrids are junk. That a small diesel engine would get the mileage, indeed they seem to do so in Europe and Great Britain, that Bozo is so hot to restrict our vehicles too. Thanks to you and the others who answered my questions without condescension and ridicule.
Yes, I can understand how the instant torque that an electric motor supplies to the wheels could make for a very fast machine, especially on take off. However, you neglect to tell us how long this thing can run between charges and how does it get its electricity.
A thought occurred to me after my reply to your last comment(#73). I realize hybrids are heavy, but is not most of the weight, or a good deal of it from the batteries? If a diesel engine was used to supply the power to the generator, greatly increased in size and output, and the batteries eliminated, wouldn’t that reduce the weight overall or at least make it the same weight without having the batteries to mess with? Or am I just way off center here?
The post was off the cuff.
The link has the videos that answer all the questions. As I said before it is very cool, in fact super cool. It is the cutting edge of electric vehicle technology
It’s got a hole in the floorboard for your feet in case you need to speed up and get out of the way of an SUV or Mack truck.
Electric motors need no clutch, where as diesel motors do.
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