Will cars ever run on pressurized air?

This is the place for any magazine-related discussions that don't fit in any of the column discussion boards below.

Is it possible?

I definitely do believe that an automobile powered by compressed air is possible.
4
57%
I definitely don't believe that an automobile powered by compressed air is possible.
3
43%
 
Total votes: 7

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haklesup
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Post by haklesup » Mon Jun 11, 2007 5:24 pm

OK, I understand, all those references you didn't look at are liars and hoaxers because your experience with horsepower tells you so.

I think the reporters probably overplayed the energy savings but you seem to go to the extreme and say it's completely not possible.

The only compressed gas here is not coming from a car.

Certainly your last set of numbers might be used to argue that compressing the air might cost more than $2 but it says nothing to the possibility of using that to propel a vehicle. Not that someone somewhere dosen't have an idea for a better compressor. (BTW, I also said before I thought the $2 refill price was outlandish, I also think it would be higher in practice)

HP, W and pennies say nothing to the volume or pressure that it buys you. No math here, just a flurry of numbers and rule of thumb conversions.

Steel air tanks weigh a lot (and not CF) but the ones in the car are spun carbon fiber and obvously much lighter (light enough for the space shuttle). The combined volume of the three tanks is apparently 52 gallons so at just under 300 ATM of pressure that means you can stuff X gallons of air at STP into the tank. (not sure of X, )

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jollyrgr
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Post by jollyrgr » Mon Jun 11, 2007 5:30 pm

Back a while ago I posted a link to a air powered car. (See my thread here: http://www.servomagazine.com/forum/viewtopic.php?t=7328) I think it is a fantasy to expect this to be practical. It is nothing more than a toy.

I want someone to post the physics of what it cost to compress 3175 cubic feet of air 4350 PSI. Everything mechanical requires "WORK". You DON'T GET SOMETHING FOR NOTHING!" How much in watts does it take to run a compressor motor to get to this tank charged? I found that the compressor runs for 3.5 hours using 230VAC but no mention of current. I further found that a tank gives approximately 46MJ of energy. (See the section on thermodynamics here: http://www.theaircar.com/data_sheet.html)

The car I linked to is expected to drive at 50 km/h (30 miles per hour) for about 10 hours a charge (this took some interpolation). Or about 500 km/tank or 310 miles/tank.

I'm getting close but keep missing the target. Based on the 46M Joules I got 12.8 KW Hours. At 7 cents a KWH this means it costs about 84 cents to recharge. Can someone show me what step I am missing in the conversion?
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Chris Smith
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Post by Chris Smith » Mon Jun 11, 2007 6:22 pm

FACT ONE

Instead of the realms of fantasy for your thoughts, simply reduce the math to what you pump in, is what you get out minus the loss.
Same HP, same time, minus 33 percent.

A Fact and then some.

FACT TWO

A bottle of Liquid Air/ LOX contains exactly one unit of energy, and that unit is costly to produce for its expelled energy output, and not enough to propel a useful automobile for any real distance.

A Fact and then some.

HP, Time expelled, volume of a bottle, all conspire to give you exactly what you put in, and that amount is fixed and limited.

A Fact and then some.

Do the numbers and the FACTS become all but obvious.

LOW powered vehicles, running in reality for short periods of time, dragging around large gobs worth of energy that weighs a ton and one hell of a inefficient means to do so.


A steam engine does much more burning grass than a bottle could ever do.

The facts are there, you can not squeeze blood out of a turnip.

And As far as I said it cant be done, sounds like your don’t read soo well.

More than a half dozen times now I have stated exactly how it can be done, and at a loss.

All very old history.

positronicle
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Post by positronicle » Mon Jun 11, 2007 6:23 pm

--Edited by Positronicle--

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Chris Smith
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Post by Chris Smith » Mon Jun 11, 2007 6:34 pm

You get out what you put in minus at least 66 percent, and that will remain a joke long before some here get their education.

A couple of HP in and a couple of HP out, great for the go cart if it can drag the heavy bottle around.

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Post by ian » Mon Jun 11, 2007 7:55 pm

I know this is a bit off topic but are you dating anybody right now positronical? I mean, are you single?

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Chris Smith
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Post by Chris Smith » Mon Jun 11, 2007 7:58 pm

His little girl, or HIM?

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Post by positronicle » Mon Jun 11, 2007 8:32 pm

--Edited by Positronicle--

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Chris Smith
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Post by Chris Smith » Mon Jun 11, 2007 8:55 pm

Yeah she is hot, lets hope the simple stuff doesnt deter her from the real world like her dad..

There is simply no room for fantasy in the real world of science or physics.

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dr_when
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Off topic nonsense

Post by dr_when » Wed Jun 13, 2007 5:47 am

Chris,

I don't mean to be critical but I get a headache when trying to read your almost-poetic non-sensical gibberish. I really try to read and understand it... but I cannot. Either you are a genius wayyyy beyond comprehension for my small brain or you are an imbecile. Please pardon this flame and I understand I am not forced to read the drivel you post but please!!!! Sheesh... not only are you insanely liberal and socialist but you rarely make any sense. I hope you enjoy the rest of your life doing and talking about whatever it is you do. But spare us!!!
"Who is John Galt?"

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Chris Smith
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Post by Chris Smith » Wed Jun 13, 2007 8:20 am

All you have to do is read the POST I made called ......

"How much energy really is there in an Air Tank?"

Its simple math.

For some here math is rocket science so it may seem complicated.

I remember my electronics class well, while trig and calc were a part of that, it was also the part most tried like hell to skip.

Nothing is impossible if you clear your mind of the fluff and eye candy so many advertisers lie about.

Start at the basics, read the post, its a great “Undeniableâ€

fripster
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now for some other opinion

Post by fripster » Thu Jun 21, 2007 1:04 pm

dear all,

I think the real issue here is that no-one can do all this math (were not clever enough), i for me can not do all this

but:

- the specs are: http://www.mdi.lu/eng/affiche_eng.php?page=minicats
- The engine will NEVER output 25HP at all times!! only when accelerating!
- The piston/crankshaft combination of the motor has a very special design that uses the adiabatic pressure to the heighest possible efficiency
- We are talking about a tested prototype that HAS BEEN SHOWN TO THE PUBLIC!
- TATA has just bought the technology from them. These people are not stupid... they would never fall for it if it was a hoax.

please prove TATA, MDI, me and the rest wrong with real calculations..

fripster
Once a WireHead, Always a WireHead

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Chris Smith
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Post by Chris Smith » Thu Jun 21, 2007 1:46 pm

I think the real issue here is that no-one can do all this math

This is exactly why Barnum and Bailey made it in the real world....

If you cant do the math, you cant go around pretending that it works either.

Any body can throw money down a drain, even an idiot that cant count.

The math never changes, its still cost 7 to 25 cents for one hp, per hour worth of charged air and that’s before the real loses come into play.

Then we get into loses and efficiencies of transference putting us down in the 25 cent per hp/ hour range, which still doesn’t cover other physical manufacturing costs or practicalities.

As to the charlatans trying to make a loser seem viable, well Ill leave that to the Rockefeller and Enrons, they have all the money in the world to prove a exorbitant and ineffective design works, but then We knew it worked 50 years ago and even then it was an exorbitant albatross.

No one really buys into fluff off the web cept the feeble and ignorant.

Who care if it works, no one can afford to run it when there are dozens of other ways to do the same thing at 30%, 50% or worse, 75% of these costs. Yeah we had the best, but they never seem to get off the shelf because there are too many Alice’s in wonderland not prepared to look, see, or hear why it doesn’t make sense to even try. Sounds good, Im sure? But so does the gold at the end of the rainbow.

For an alternate power web site go to www.fantasypower.com

Rube Goldberg is definitely behind this post of Air Powered Cars, and it is hilarious to say the least.


Adiabatic

In this process there is no heat transfer to or from the system, and all supplied work is added to the internal energy of the gas, resulting in increases of temperature and pressure.


No such thing happens with compressed air engines, in the making or using.... internal piston engines [or turbines] require 1000 psi or greater, and heat is always applied and lost in any transfer.


- The piston/crankshaft combination of the motor has a very special design that uses the adiabatic pressure to the heighest possible efficiency

Horse manure.


- We are talking about a tested prototype that HAS BEEN SHOWN TO THE PUBLIC!

And the little people say there is gold at the end of the rainbow!

Enron, enron, come in, moon base calling.

- TATA has just bought the technology from them. These people are not stupid... they would never fall for it if it was a hoax.

No, like enron, your stupid not them, they are republican and enjoying your stupidity.

Got a buck to spare mister, Id gladly pay you on friday, for a hambuger I just ate today.....

fripster
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Post by fripster » Fri Jun 22, 2007 12:10 pm

@chris: please do not let go of netiquette... even if we do have opposite opinions. I like a civilised discussion..

fripster

BTW: can you please comment on my remark that the motor will ONLY have to put out a lot or power when accelerating.... i'm curious...
Once a WireHead, Always a WireHead

Gary
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Post by Gary » Fri Jun 22, 2007 1:14 pm

I remember seeing a picture of a mining locomotive that used compressed air. This is one application that actually makes sense. It looked a lot like a conventional old fashioned steam locomotive, but had a big tank where the boiler would normally be. Somebody bought it at scrap value and later made a steam locomotive out of it as a hobby or tourist attraction.

As a compressed air mine locomotive it might not have been terribly efficient, but at least it didn't give out any noxious fumes. In fact the waste air would have helped ventilate a mine a little. They also use high pressure air in mines to operate drills, so filling it up would have been easy.

Compressed air has been around for a long time, if it made sense in the past it would still be used as a motive force. It didn't make much sense in the past except in special circumstances.

IMHO

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