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View Full Version : If the exhaust comes out warm does it run on Hot Air?



Spin Doctor
05-21-2007, 05:23 PM
http://www.theaircar.com/models.html

From India of all places. In theory it sounds good. I'd like to see how it really works.

Fasttrack
05-21-2007, 05:56 PM
Of course the compressors for the "air station" are run off of massive diesel engines that belch unrestricted sooty smoke into the atmosphere... :D :D :D

ckelloug
05-21-2007, 08:30 PM
This is just basic physics. Compress air and use it to run an engine. Their cycle is a lot better than the pure adiabatic expansion of the gas often used to model such processes but there is no new science here. What this car has is good engineering with no novel science. It starts out more promising than being a loonie waste of energy like the guys trying to store hydrogen via metallic aluminum reacting with water. . . so it can never fall that far :D

What's novel about their approach is their use of technology to reduce the weight of the vehicle. One of the reasons you can't just slap a super efficient engine in a Ford Expedition is the fact that the cotton pickin thing needs an astronomical amount of energy just to move it's carcase much less move it well or quickly. When you start out with a vehicle like the air car that has less than a gallon of gasoline worth of energy in the tanks, you have to use that energy much more efficiently to have a viable product. I imagine that you will notice a decline in acceleration in this vehicle after eating a few large meals before you even have to let out your belt a notch.

It might be imperfect but it's better than watching our near-bankrupt American automakers put out another equivalent of the fictitious "Canyonero" SUV that seats 29 (from a crazy song on NPR's Car Talk show).

Carld
05-21-2007, 08:54 PM
If it works as well as they say it would be a nice town car for short runs. I never did see a price.

Evan
05-21-2007, 09:08 PM
What isn't at all obvious on the web site is that the prime mover in that car is a gasoline engine. The car doesn't run on air, it runs on gasoline. The engine is used to charge the air tanks and it is used on air for low speed and short range (really short range). On air the best it can do is 50kmh, about 30 mph. The best range the prototype has made on air in trials is 7.2 kilometres, or about 4 1/2 miles. Any other numbers are projections based on proposed but non-existent technology features.

Using compressed air as a power source is the most inefficient possible way to move a vehicle. A horse would be better.

A.K. Boomer
05-22-2007, 08:28 AM
What a pipe dream, wonder how bad the crash tests are when the tank "pops" This is the type of crap that we will see allot more of in the near future --- More impractical wastes of time and resources...

J Tiers
05-22-2007, 12:45 PM
Compressed air is indeed inefficient, and is best used where you have to not have electric, or fire, exhaust, etc, etc, etc.

Most such schemes are lossy, and the "inventors" would be far better off using a very efficient gasoline engine.

john hobdeclipe
05-22-2007, 02:33 PM
Compressed air tanks

One of the most frequently asked questions is about the safety of the compressed air storage tanks. These tanks hold 90 cubic metres of air compressed to 300 bars. Many people ask whether this system is dangerous in case of an accident and if there is a risk of explosion. The answer is NO. Why? Because these are the same tanks used to carry the liquid gas used by buses for public transport. The tanks enjoy the same technology developed to contain natural gas. They are designed and officially approved to carry an explosive product: methane gas.

In the case of a major accident, where the tanks are ruptured, they would not explode since they are not metal. Instead they would crack, as they are made of carbon fibre. An elongated crack would appear in the tank, without exploding, and the air would simply escape, producing a loud but harmless noise. Of course, since this technology is licenced to transport an inflammable and explosive gas (Natural gas), it is perfectly capable inoffensive and non-flammable air.

I don't care what kind of bullsheet these people are talking, I don't want to be anywhere close to a tank full of anything pressurised to 4200 psi when that tank's structural integrity has been compromised.

It may fail very nicely and safely in their lab, not so on the road, in a collision, totally uncontrolled.

A.K. Boomer
05-22-2007, 08:31 PM
Yeah, they say nothing about that kind of air pressure being able to rip through sheet metal and torso's and stuff...

Evan
05-22-2007, 10:09 PM
The hazard aspect of compressed air isn't likely to be a show stopper. People are very willing to accept those sorts of risks, scuba divers for instance. The real problem is the thermodynamic efficiency, or total lack of it.

dicks42000
05-22-2007, 11:45 PM
Nothing really new here, mybe just some engineering refinements. Air, natural gas & other gasses, flammable & inert are often stored at very high pressures.
Mines, chemical plants & explosive works often used compressed air locomotives in hazardous atmospheres. (Think a steamer, less the boiler & the fire.) Also an accountants wet dream 'cause no prima donna locomotive engineer with a license required. No fireman, no flames, smoke & soot and best of all, no steaming up time in the morning. (Unproductive, but those dirty workers still want to be paid...) Most large plants also already had a large air system anyway. Ingersoll-Rand made some, Porter too, iirc. 15 inch gauge was/ is common for mines.
Also there was a type of steam loco that used hot water at high pressure. Sort of like a giant thermos bottle on a steam loco chassis. Once again, no licensed engineer, no fireman, no flames & smoke required & steaming up in the morning (unproductive time...!!!). Loco was "recharged" from the plant hot water heating system. Worked well where hotwater or steam was used for process heating. (Refinery, Chem. plant...)
Charlie Coghill might know the guy & his wife, but around the North West here, there is a steam guy who built a replica of a Welsh mine loco. Think a vertical boiler & engine on a small flatcar; 15 inch ga. track runs into his garage...;) They are members of his steam society, I believe. My kind of neighbour.
Maybe someone should drag home an old pneumatic mine locomotive, restore it & lay tracks around the yard. (They used to be aboandoned around hardrock mining areas like BC, Colorado etc...
I still like steam, soot & smoke though.
Rick

A.K. Boomer
05-23-2007, 12:43 AM
The hazard aspect of compressed air isn't likely to be a show stopper. People are very willing to accept those sorts of risks, scuba divers for instance. The real problem is the thermodynamic efficiency, or total lack of it.

Thats a fact, the thermodynamic inefficiency is two fold, (or more) not only do they have to worry about all the losses that are typical to what we use right now --- they have to take these existant losses and then compound them by having to then run a compressor (more loss) and then even more loss will occure when the compressed air cools in the storage tank and has to be used at a reduced pressure then when it was put in, it would be terrible if it wasnt so laughable...