Compressed Air powered, zero emission cars - for $6.5K each

BobG wrote:
> This site has a table of energy density by weight and volume and
> compressed air is worse than batteries. (Hint... most air compressors
> I've seen are big noisy 220V several HP contraptions and they huff and
> puff and finally shut off at a whopping 150 psi.)
> http://xtronics.com/reference/energy_density.htm

Well no, scuba tanks go to around 2500 psi, and there is no practical
reason a compressor can't be designed to be 100% wind powered without
any electricity at all.

Don't knock compressed air, a metal tube is easier and cheaper to
manufacture than any battery (and does not need nasty acid and lead),
and combustion engine generators can be adapted to run off compressed
air.

There is nothing stopping a reasonably bright engineer making the whole
setup, wind-compressor, tank and air powered generator, without
depending on a battery factory overcharging him on a short-lived,
complex energy storage device.

Joe Fischer wrote:
> On 4 Oct 2006 06:32:41 -0700, "BobG" > wrote:
>
> >This site has a table of energy density by weight and volume and
> >compressed air is worse than batteries. (Hint... most air compressors
> >I've seen are big noisy 220V several HP contraptions and they huff and
> >puff and finally shut off at a whopping 150 psi.)
> >http://xtronics.com/reference/energy_density.htm
>
> Energy density by weight is not an issue except
> for big hills, one of the reasons for using air is to have
> regenerative braking, and with regenerative braking,
> weight is not anywhere near as critical, if at all.
>
> And storage is apparently not at 150 psi,
> it is hundreds of bars, which is 3000 psi or more.
> While storage tanks are high tech for this
> pressure range, it makes a big difference in
> whether or not the vehicle has any utility.
>
> If regenerative braking were perfect (100
> percent efficient), the energy needed to make
> a trip would only be the bearing friction (which
> should be negligible for good bearings), rolling
> friction (which can be reduced by less flex in
> the tires), and air resistance (which should also
> be negligible at low speeds and no wind).
>
> It is these facts that make EVs or any
> other technology that supports good regenerative
> braking viable at all.
>
> The auto industry has not placed good
> physics above inept road testing programs, and
> they need to start from scratch, with good physics,
> and build cars that take almost no energy at all
> to make a trip on level ground!
> Only then will the myth of weight being
> a critical issue be discarded and the understanding
> that it has been hills and overpowered ICE engines
> that have been wasting all the energy (plus having
> an engine running and wasting energy waiting at
> traffic lights).
>
> Joe Fischer

Another big waster is inefficient driving. I drive my car like a
bicycle, there is absolutely no need to use an engine downhill, so in
goes the clutch on every slope.

Joe Fischer wrote:
> On 4 Oct 2006 "John S." > wrote:
>
> >But the one indicating they are both cooling the air to minus 100
> >degrees and compressing it to 4,500 psi indicates a lot of energy is
> >being transferred to come up with a supply of air that is packed
> >tightly enough to provide sufficient expansive power to propel a car.
>
> Cooling the air may be part of another process,
> maybe the heat extracted is used for something.
>
> But compressing the air is NOT a waste of energy,
> it IS the energy that will move the vehicle. :-)

Energy isn't wasted, it is just converted to another form.
Unfortunately not all of it makes it to the intended recipient, which
in this cas is an air powered car. If you look at the chain of events
required to convert the energy from burning coal into ultra-cooled
highly compressed air there are many places where energy is diverted.
The proponents of this idea ignore that reality.


>
> The argument of compressing combustible fuels
> being a waste of energy is valid, but compressing in and
> of itself is not what causes the waste, it is not using the
> compression for anything after that which is wasteful.
>
> >That transferred energy comes at a financial and environmental cost
> >which appears to be ignored. If they are able to store compressed air
> >at those pressures and temperatures do you know how large and heavy
> >would the storage tank(s) have to be to give the car a range of 200
> >miles.
>
> There are no ICE vehicles to compare this against,
> because air may be one of about four possible viable
> regenerative braking systems.

How would a regen system be implemented here. To power a generator to
charge an auxiliary battery or to power a compressor?


>
> I doubt if 200 mile range is offered or needed,
> I drove a cab in 1950, 12 hours or more per day, and
> rarely went 200 miles.
> Air tanks could be exchanged, although they
> may be heavy, but possibly not even as heavy as
> a liquid propane tank if the air is not liquified.


Because of size, tank exchange would not be practical for most
applications. A recharge would make the most sense I think.

>
> The idea may be oversold, or suspicious,
> after all it came from France :-), but for certain
> uses it may be an extremely useful technology.

Certainly possible and we should keep trying new ideas. But my biggest
complaint is that the proponents of that air car, like the proponents
of battery power and fuel cells choose to ignore the significant costs
that impact those ideas.

>
> The motors look identical to hydraulic
> motors being used on aircraft in 1946 when I
> was an A & E mechanic instructor, so I have
> an open mind as to how much range a tank
> of air will hold.
>
> Without the possibility of regenerative
> braking, the idea would be rather dumb.
> Contests should be held where the
> least amount of energy would be used over
> a closed course with traffic lights, stop lights,
> and some straight-aways, because regenerative
> braking is the key to range in city driving.

Contests like that are alwaus a good idea. I know a gal that has
crewed on more than one car in the solar power race in Australia. The
cars keep getting better.

>
> Joe Fischer

Hoggle wrote:
> John S. wrote:
> > I got lost trying to read through all of your links, so I'll give it a
> > try later with a cup of coffee.
>
> I apologise for using referenced evidence in my arguments. I realise I
> am virtually unique in this regard on usenet.
>
> http://www.theaircar.com/
> This website will answer many of your questions (although it is badly
> out of date and many of the links have not been changed to stay on the
> English site, so being able to read spanish will help).

No apology needed. And I would like to read as much useful information
on this topic as available.

On 4 Oct 2006 14:09:39 -0700, "Hoggle" >
wrote:

>John S. wrote:
>> I got lost trying to read through all of your links, so I'll give it a
>> try later with a cup of coffee.
>
>I apologise for using referenced evidence in my arguments. I realise I
>am virtually unique in this regard on usenet.

I don't think John S. was having a go at anyone but himself about
getting lost. He was not having a go at you.

On 4 Oct 2006 14:15:12 -0700, wrote:

But how long-lived is a tank that is being asked to store 4,500 PSI of
compressed air?

And we are not all reasonably bright engineers, who are also capable
of actually making the gear. In fact I know many reasonably bright
engineers who know that it's far brighter to stick to designing and
let a reasonably competent technician do the actual building. So some
reasonably bright person, or group, starts making them for
others....and overcharging for it.

>There is nothing stopping a reasonably bright engineer making the whole
>setup, wind-compressor, tank and air powered generator, without
>depending on a battery factory overcharging him on a short-lived,
>complex energy storage device.

OldNick wrote:
> I don't think John S. was having a go at anyone but himself about
> getting lost. He was not having a go at you.

Fair point - my reply was merely facetious, not offended

wrote:
> BobG wrote:

> There is nothing stopping a reasonably bright engineer making the whole
> setup, wind-compressor, tank and air powered generator

Or also covering the whole car in solar panels. Any time that the sun
is up, it could be running a small on-board compressor. It's obviously
not enough to power the car down the road by itself, but with a
*cumulative* effect, it may extend the intervals between 'refilling'.
After all, cars spend most of their life at rest, sitting outside.

Before I get flamed into oblivion, let me note that I am aware that
solar panels and generators may add a weight problem and be
counterproductive. It's just an idea.

-phaeton.

On Thu, 05 Oct 2006 06:22:43 +0800, OldNick >
wrote:

>And we are not all reasonably bright engineers, who are also capable
>of actually making the gear.

Only a dim engineer would consider it as it's so horribly inefficient.
But one needn't make anything at all. Instead all you need is enough
land for several Bowjons and tanks. They can even be had surplus and
relatively cheap. The fact that it's actually easy, and that pretty
much nobody does it, ought to tell you everything you need to know.
About the only remotely practical application would be to run a
scrounger's shop tools. I have a neighbor who says he's going to do it
some day. It'll only be about the hundredth major mistake he's made
since I've known him. :-)

Wayne

On 4 Oct 2006 14:58:14 -0700, "John S." > wrote:

>Joe Fischer wrote:
>> On 4 Oct 2006 "John S." > wrote:
>> >But the one indicating they are both cooling the air to minus 100
>> >degrees and compressing it to 4,500 psi indicates a lot of energy is
>> >being transferred to come up with a supply of air that is packed
>> >tightly enough to provide sufficient expansive power to propel a car.
>>
>> Cooling the air may be part of another process,
>> maybe the heat extracted is used for something.
>>
>> But compressing the air is NOT a waste of energy,
>> it IS the energy that will move the vehicle. :-)
>
>Energy isn't wasted, it is just converted to another form.

I was thinking some may have been relating to
the compressing of hydrogen or natural gas for motor
fuel, where the compressing is wasted.

>Unfortunately not all of it makes it to the intended recipient, which
>in this cas is an air powered car.

I suspect it is more efficient than burning fossil
fuel in an ICE.

> If you look at the chain of events
>required to convert the energy from burning coal into ultra-cooled
>highly compressed air there are many places where energy is diverted.
>The proponents of this idea ignore that reality.

They don't have coal (to speak of) in France,
and they don't have oil or natural gas, so if off peak
nuke plants compress the air, the cost of the grid
power is the only number to consider in efficiency.

>> The argument of compressing combustible fuels
>> being a waste of energy is valid, but compressing in and
>> of itself is not what causes the waste, it is not using the
>> compression for anything after that which is wasteful.
>>
>> >That transferred energy comes at a financial and environmental cost
>> >which appears to be ignored. If they are able to store compressed air
>> >at those pressures and temperatures do you know how large and heavy
>> >would the storage tank(s) have to be to give the car a range of 200
>> >miles.
>>
>> There are no ICE vehicles to compare this against,
>> because air may be one of about four possible viable
>> regenerative braking systems.
>
>How would a regen system be implemented here. To power a generator to
>charge an auxiliary battery or to power a compressor?

No, an air motor is also a compressor (it may need
valves switched, I haven't thought about it.
The success or failure of the car companies will
tell if it is economical or not.

>> I doubt if 200 mile range is offered or needed,
>> I drove a cab in 1950, 12 hours or more per day, and
>> rarely went 200 miles.
>> Air tanks could be exchanged, although they
>> may be heavy, but possibly not even as heavy as
>> a liquid propane tank if the air is not liquified.
>
>Because of size, tank exchange would not be practical for most
>applications. A recharge would make the most sense I think.

After I wrote that I found info on refill stations,
and I surmise that transferring air under pressure may'
not have the heat changes seen in the original compression.

>> The idea may be oversold, or suspicious,
>> after all it came from France :-), but for certain
>> uses it may be an extremely useful technology.
>
>Certainly possible and we should keep trying new ideas. But my biggest
>complaint is that the proponents of that air car, like the proponents
>of battery power and fuel cells choose to ignore the significant costs
>that impact those ideas.

I didn't see anything about government funding
on this, and a lot of people may not realize that some
government funding requires the inventor/developer
to forfeit some patent rights.

>> The motors look identical to hydraulic
>> motors being used on aircraft in 1946 when I
>> was an A & E mechanic instructor, so I have
>> an open mind as to how much range a tank
>> of air will hold.
>>
>> Without the possibility of regenerative
>> braking, the idea would be rather dumb.
>> Contests should be held where the
>> least amount of energy would be used over
>> a closed course with traffic lights, stop lights,
>> and some straight-aways, because regenerative
>> braking is the key to range in city driving.
>
>Contests like that are alwaus a good idea. I know a gal that has
>crewed on more than one car in the solar power race in Australia. The
>cars keep getting better.


I saw the solar cars go through here on the way
from Florida to Detroit a few years ago.

I really think the effort behind that particular
air car is the serious problem of fuel of all kinds in
Europe.

And if it helps alleviate that problem, great.

The only thing I would suggest is not to
increase the diameter of the tanks, at 20 inches
and 4500 psi, the belt stresses are approaching
the burst pressure, even with carbon fiber wrap.

Joe Fischer