[SolarDave]

[/quote]

10-20 percent efficiency is typical. 50 percent is unheard of.

Quote from this site:

"Rule of Thumb: Eighty percent of the electrical energy used by a compressor is converted to heat"

Compressed Air Challenge

And more:

Compressed Air System Efficiency

Air compressors are far better at producing heat than they are at storing power. Even if the reverse were true - and air motors were tremendously effcient (and they are not) by the time the air gets to the motor 4/5 or more of the original energy has already been wasted. Not good at all.

[bobbyald]

I read in todays London Metro about a compressed air car called the MiniCAT developed by Moteur development International of France.

It is made of fibreglass and costs £5,500 ($11,000).
It is claimed that on just a single £1 ($2) charge it can do 8 hours of city driving or 124 miles.

I would be interested to know what others make of these claims?

[yesplease]

The overall efficiency of a typical compressed air system can be as low as 10-15%.

Ouch. That's a lot of current. I wonder what the peak is?

[emersonbiggins]

Strap myself atop a 4000 PSI tank of compressed air?

No thanks, I'd rather tinker with some hand grenades.

[yesplease]

Only in Amerika would someone be worried about 15kwh of compressed air, but feel fine with 300kwh of gasoline. Feel free to play with handgrenades. And don't forget to post a video on youtube. It's only funny until emersonbiggins loses an eye, then it's hilarious.

[emersonbiggins]

Gasoline tanks explode upon impact? News to me; I've never seen a car accident look like it does in the movies.

To be fair, I don't exactly drive a gasser golf-cart, which is exactly what the people at aircar would like me to do with a tank of compressed air. No thanks, we'd be better off with batteries.

[yesplease]

It depends on the cost of available energy and competing battery technology. The are situations where an aircar with a larger tank would be cheaper than an EV and vice versa. Like most things, it depends...

Gasoline tanks explode upon impact? News to me; I've never seen a car accident look like it does in the movies.

A few details about our vehicles´ technology

Compressed air tanks Brake energy recovery
The body The air filter
Chassis Electrics system

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.

300 bars of compressed air stored on board the vehicle, Is this dangerous for the passengers?
Compressed air tanks have already been proven safe by one of our partners EADS(AIRBUS). This company's reputation in the aeronautical field is unprecedented, given the reliability of its tanks. What's more, the compressed air does not present any risk of explosion. Countless test have been carried out in the most extreme conditions (gun shoots, resistance to fire...) to guarantee passenger safety in every possible condition. The high pressure tanks have been developed using a similar technology to those used in natural gas vehicles and by firefighters. All are produced with carbon fiber over plastic.
The tanks that MDI puts in its vehicles are similar to those already in use in natural gas busses in Germany and other countries.

In addition to playing with grenades, you may also want to take a few shots at your car's gas tank, preferably when it's low on fuel, at close range. I also suggest staying away from any CNG buses if I were you. very dangerous...

[emersonbiggins]

I also suggest staying away from any CNG buses if I were you. very dangerous...

Tanks of CNG @ 200 bars placed 10' atop a 40,000 lb city bus is one thing (little to no rupture risk); a tank @ 300 bars in the backseat of a 500 lb ultralight is quite another, though. Imagine the impact with a truck or, yes, even a city bus.

It's like comparing apples with penguins.

[smallpoxgirl]

i.e. tractor-trailers.

Just off the top of my head, I'd say that if you're driving that little cardboard box of a car around at 12mph and you get hit by a semi, your probably not going to live long enough to need to worry about the air tank.

[emersonbiggins]

i.e. tractor-trailers.

Just off the top of my head, I'd say that if you're driving that little cardboard box of a car around at 12mph and you get hit by a semi, your probably not going to live long enough to need to worry about the air tank.

And, thus, the folly of ultralights. I doubt air could run any vehicle remotely considered crashworthy, and you're unlikely to recruit converts as long as 80,000lb trucks are on the road.

[yesplease]

These could probably use a full cage, and full race gear if the driver is worried about getting hit by a 40-80k lb vehicle. But, then again, so could everything else on the road today.

And, thus, the folly of ultralights.

Everything is an ultralight compared to a semi.
That has more to do with separate infrastructure for commercial transport imo. It'd equalize the playing field in a crash, and shift the burden of taxation from the general public to what does the most damage.

[emersonbiggins]

Everything is an ultralight compared to a semi.
That has more to do with separate infrastructure for commercial transport imo. It'd equalize the playing field in a crash, and shift the burden of taxation from the general public to what does the most damage.

Couldn't agree more.

[lys3rg0]

I recently read an article in a magazine i can no longer find about a european prototype for a car based on an engine working on compressed air. autonomy is about 200 km, and the recharge is electric. Does anyone know anything about this kind of technology? I found a site talking about an advanced version: http://www.theaircar.com/
However this refers to a "hybrid" fossil fuel - compressed air version. I'm interrested in the air only car, especially the way the engine works...

edit: found smth on youtube http://www.youtube.com/watch?v=D-A3XHFT5qc
carbon fiber tanks, 300 bar - that sounds expensive

[master_rb]

thanks for posting, i really enjoyed the youtube video - looks interesting, as a PO optimist i'll be checking this technology, i hope it's not one of those technologies that promise a lot but you never hear about it later

i went to their website at
http://www.theaircar.com/

That's what they have in their FAQ's

Since it is necessary to produce electricity to recharge them, are your vehicles really clean?

Effectively, there is no technology that permits for completely pollution free vehicles. We feel that the creation of electricity and compressed air in rural areas is more ecologically friendly than the combustion of fossil fuels in urban areas. Therefore, our current objective is not to produce a completely pollution free car, but rather, to produce a car that emits the minimum amount of pollution possible.


to me they look pretty honest, let's wait and see if they can deliver their promises

[JPL]

Compressed air is a really interesting means of power storage - also of transmission if you get the technology right. It's used extensively today, in engineering workshops and also the mining industry.

Perhaps the best-known historical application was Brunel's 'Atmospheric Railway' which used a vacuum-pipe to suck the trains along. He had major problems with the infrastructure (over 150 years ago, mind) but I think most of these problems could be solved with modern materials.

See http://en.wikipedia.org/wiki/Atmospheric_railway for details.

JPL

[Minvaren]

From their FAQ:

How much will the cars cost?
In Europe the MiniCAT's will be put forward at a base price of 6 .860 Euros (without Iva) except in some options.
The CityCAT's will be put forward at a base price of 9 .460 Euros (without Iva) except in some equipped options. Taxes and subsidized options have not yet been calculated.

Sounds like this could make a dent in oil consumption, provided that the power grid could keep up.

[Kingcoal]

I'd give the comp-air car a better chance than the hydrogen fuel cell car, but that's not saying much.

[Hawkcreek]

--

[Aaron]

Ahhhhhhhhhhhhhhhhhh!!!!!!!!!!!!



<cough cough>

Ahhhhhhhhhhhhhhhhhh!!!!!!!!!!!!

Guys... I hate math too... but... ?!?

Ahhhhhhhhhhhhhhhhhh!!!!!!!!!!!!

[JRP3]

Aaron's right. Compressing air then decompressing it to run a motor is really inefficient. They also are way optimistic on their range estimates, they have not achieved anything close to that.