Behold the CityCAT air car, powered by compressed air.

No it won't.

They are *less* efficient that EVs, so need MORE energy to keep them running.

Where exactly ? Except in your fantasies ?

Damn you're an ignorant prick of the first order. Use the same cutesy 'solar
energy' in EVs and you'll easily go *TWICE* as far - probably more since EVs can
reclaim energy by regenerative braking.

Graham

 

A *non-sell* for general road use.

Graham

 

A *non-sell* for general road use.

Graham

 

All true, but batteries are every bit as heavy as air tanks, in their
current state of development. Air is as good an alternative source of energy
as any other, and it's the combination of various technologies that will
save us, not one specific one. Air is perfectly clean and endlessly
renewable, so efficiency can take a back seat till better options come
along. Lord knows it's better than alcohol. It's "alternative thinking"
that's important, not necessarily relative efficiency. In other words, don't
shoot it down cause it's not perfect. What's most important at this point in
time is that it's CLEAN. Unless you're off the grid on solar and wind,
electricity is anything BUT clean.

 

All true, but batteries are every bit as heavy as air tanks, in their
current state of development. Air is as good an alternative source of energy
as any other, and it's the combination of various technologies that will
save us, not one specific one. Air is perfectly clean and endlessly
renewable, so efficiency can take a back seat till better options come
along. Lord knows it's better than alcohol. It's "alternative thinking"
that's important, not necessarily relative efficiency. In other words, don't
shoot it down cause it's not perfect. What's most important at this point in
time is that it's CLEAN. Unless you're off the grid on solar and wind,
electricity is anything BUT clean.

 

Compressed air is only a storage medium, just as batteries, hydrogen or
flywheels are. According to the Wikipedia entry on energy density,
http://en.wikipedia.org/wiki/Energy_density, it competes poorly in that
category. Even excluding the weight of the tanks, just the weight of the air
itself, it weighs 2-3 times as much as the equivalent capacity of Li-Ion
batteries and has at least 7 times the loss. (The practical recovery
efficiency of compressed air is given as 64%, which is the efficiency if the
driven device is 100% efficient over the entire range of pressure. This
requires the air pressure used not drop much below the 20 bar pressure they
cite; darned Second Law of Thermodynamics!) It fares even worse in energy
density against compressed hydrogen powering a fuel cell, which offers about
250 times the energy density of compressed air.

Mike

 

Compressed air is only a storage medium, just as batteries, hydrogen or
flywheels are. According to the Wikipedia entry on energy density,
http://en.wikipedia.org/wiki/Energy_density, it competes poorly in that
category. Even excluding the weight of the tanks, just the weight of the air
itself, it weighs 2-3 times as much as the equivalent capacity of Li-Ion
batteries and has at least 7 times the loss. (The practical recovery
efficiency of compressed air is given as 64%, which is the efficiency if the
driven device is 100% efficient over the entire range of pressure. This
requires the air pressure used not drop much below the 20 bar pressure they
cite; darned Second Law of Thermodynamics!) It fares even worse in energy
density against compressed hydrogen powering a fuel cell, which offers about
250 times the energy density of compressed air.

Mike

 

Michael Pardee said the following on 5/26/2007 8:23 PM:

Entropy just ain't what it used to be.

 

Michael Pardee said the following on 5/26/2007 8:23 PM:

Entropy just ain't what it used to be.

 

But we have more of it than ever!

 

But we have more of it than ever!

 

Back in the day they called the cure-all products, 'Snake oil.' If somebody
could actually come up with an alternated fuel that would not cost any more
to produce, deliver, sell, meet all the governmeant regulations as good as
crude oil, that was cleaner, they would be doing so. If any manufacture
could build a vehicle that would be as powerful, as roomy and salable, meet
all the governmeant regulations, that would get 20 miles more per gallon
they would be doing so. Nobody could stop them, and in either example they
would make that person billions of dollars.

mike

 

Back in the day they called the cure-all products, 'Snake oil.' If somebody
could actually come up with an alternated fuel that would not cost any more
to produce, deliver, sell, meet all the governmeant regulations as good as
crude oil, that was cleaner, they would be doing so. If any manufacture
could build a vehicle that would be as powerful, as roomy and salable, meet
all the governmeant regulations, that would get 20 miles more per gallon
they would be doing so. Nobody could stop them, and in either example they
would make that person billions of dollars.

mike

 

Air tanks are pretty well developed. They are not complicated. They just
have a lot of space and a valve.

Wrong. Air is not a source of energy. The air has to be compressed. That
takes energy, whether it's electricity, gasoline or someone compressing
the air with a hand pump.

yet this is not more than a storage form of electricity. It is really no
different than if you charge a battery in the car. Air doesn't compress
itself.

Jeff

 

Air tanks are pretty well developed. They are not complicated. They just
have a lot of space and a valve.

Wrong. Air is not a source of energy. The air has to be compressed. That
takes energy, whether it's electricity, gasoline or someone compressing
the air with a hand pump.

yet this is not more than a storage form of electricity. It is really no
different than if you charge a battery in the car. Air doesn't compress
itself.

Jeff

 

I could see compressed air powering lawnmowers, go carts, golf carts,
and fork lifts. In theory, you could have quick-connect bottles, making
it all practical (the bottles could be refilled by a compressor). That
would certainly be cleaner than using small internal combustion engines.

Other than those sorts of uses, I don't see many possible markets for
compressed air.

Jeff

 

I could see compressed air powering lawnmowers, go carts, golf carts,
and fork lifts. In theory, you could have quick-connect bottles, making
it all practical (the bottles could be refilled by a compressor). That
would certainly be cleaner than using small internal combustion engines.

Other than those sorts of uses, I don't see many possible markets for
compressed air.

Jeff

 

As long as they are still viable, it doesn't matter that they're less
efficient than EV's, because the environmental impact is far less than fuel
burning cars, and even EV's. I personally think that if it is a viable
technology, then it is far more attractive than EV's even if they require
more refills. Although EV's are potentially a safer alternative to fuel
burning cars they still have a large environmental impact. The problem is
that it is far down the road and not as visible to the public. Has anyone
ever thought of what kind of negative impact the manufacturing of fuel cells
has, or what the impact of disposal will have? What will be done with all
the chemicals? I think EV's are a short term solution, but in the long term
it's a dangerous technology.

 

As long as they are still viable, it doesn't matter that they're less
efficient than EV's, because the environmental impact is far less than fuel
burning cars, and even EV's. I personally think that if it is a viable
technology, then it is far more attractive than EV's even if they require
more refills. Although EV's are potentially a safer alternative to fuel
burning cars they still have a large environmental impact. The problem is
that it is far down the road and not as visible to the public. Has anyone
ever thought of what kind of negative impact the manufacturing of fuel cells
has, or what the impact of disposal will have? What will be done with all
the chemicals? I think EV's are a short term solution, but in the long term
it's a dangerous technology.

 

I disagree about ignoring the inefficiency. Worse, even a simple requirement
like passenger heat is not presently in TheAirCar design. The manufacturer
claims TheAirCar is quieter than conventional combustion engines (listen to
the low speed demo and you may doubt even that) but admits it lacks the
silence of EVs. EVs have so many advantages and are well enough proven that
competing technologies can't just say, "We can do half that stuff at half
the efficiency!" and expect a following. The manufacturer's promo material
shows lift trucks powered by air, but battery powered lift trucks have been
popular for many decades. The company doesn't even speculate when production
will begin. In the meantime, production EVs have actually been on the road.
Compressed air is way too little, too late.

Do you have any particular reason for concern about battery disposal
(recycling) as currently carried out? In the US we go through roughly a
hundred million lead-acid car and truck batteries every year, and those are
about as toxic as batteries come. I think if it were a problem we'd be
hearing about it.

Mike