Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Berkeley Engineers Have Some Bad News About Air Cars

timothy posted more than 4 years ago | from the puff-the-magic-dragon-was-involved dept.

Transportation 278

cheeks5965 writes "We've argued before over compressed air vehicles, a.k.a. air cars. Air cars are an enchanting idea, providing mobility with zero fuel consumption or environmental impacts. The NYTimes' Green Inc. blog reports that the reality is less rosy. New research from UC Berkeley and ICF International puts a period at the end of the discussion, showing that compressed air is a very poor fuel, storing less than 1% of the energy in gasoline; air cars won't get you far, with a range of just 29 miles in typical city driving; and despite appearing green the vehicles are worse for the environment, with twice the carbon footprint as gasoline vehicles, from producing the electricity used to compress the air. Given these barriers, manufacturer claims should definitely be taken with a grain of salt."

cancel ×

278 comments

Sorry! There are no comments related to the filter you selected.

"zero fuel"? (2, Insightful)

oldhack (1037484) | more than 4 years ago | (#30186958)

How would you compress the air in the first place?

Re:"zero fuel"? (2, Informative)

AmigaHeretic (991368) | more than 4 years ago | (#30187034)

Solar panel on your garage.

Re:"zero fuel"? (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#30187162)

If a smoker brought an aircar in for service, it should be immediately considered out of warranty. Then the smoker should be arrested and sent to Guantonomo. In fact, that's what Guantonomo should be for - smoker prison.

Re:"zero fuel"? (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#30187220)

Really? I think it should be for irrational people like yourself. If we got rid of all of them/you, then the rest of us could get with our lives and not have to please everyone with PC bullshit.

Re:"zero fuel"? (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#30187252)

Whoosh!

Re:"zero fuel"? (3, Insightful)

oldhack (1037484) | more than 4 years ago | (#30187264)

Does it involve an electric middle stage? If so, electric energy storage would be more efficient, I'm guesssing?

Re:"zero fuel"? (1)

westlake (615356) | more than 4 years ago | (#30187662)

Does it involve an electric middle stage?

How can you compress air efficiently and economically without a mechanical compresor?

Re:"zero fuel"? (1)

Migraineman (632203) | more than 4 years ago | (#30187784)

Heat it with a large pile of burning coal? You can add some water to the air to enhance the effect.

Alternatively, you could acoustically excite the air in a resonant chamber, and pick off the high pressure gas at the peaks of the standing waves. Technically that's a mechanical method, but not of the typical piston or rotary type.

Re:"zero fuel"? (0)

Anonymous Coward | more than 4 years ago | (#30187618)

ah, sweet, it would fuel it while I'm sleeping.. oh, wait..

Re:"zero fuel"? (1)

ChipMonk (711367) | more than 4 years ago | (#30187724)

And that's even less efficient than solar on the car itself. Remember, no energy conversion is 100% efficient. The fewer conversion stages the better.

Re:"zero fuel"? (1, Funny)

Anonymous Coward | more than 4 years ago | (#30187636)

1. Dig really deep hole
2. Drop tank to bottom of hole
3 Seal tank
4 Raise tank
5 Profit!

Re:"zero fuel"? (1)

Ex-MislTech (557759) | more than 4 years ago | (#30187858)

One way to compress air for near free would be to have pneumatic braking
at all off ramps on highways, and at all stop lights as they go red.

Regenerative braking in hybrids work in a similar but electrical manner.

"Dompressed air" you say? (0)

sys.stdout.write (1551563) | more than 4 years ago | (#30186966)

Hmmm...

Re:"Dompressed air" you say? (1)

SteveFoerster (136027) | more than 4 years ago | (#30187706)

Finally, a use for the downpressor man [lyricsmode.com] !

Newest entry in Google's index: (0)

140Mandak262Jamuna (970587) | more than 4 years ago | (#30186972)

dompressed.

Re:Newest entry in Google's index: (1)

shogun (657) | more than 4 years ago | (#30186984)

Unfortunately its not a googlewhack: Results 1 - 10 of about 2,550 for dompressed

Re:Newest entry in Google's index: (0)

Anonymous Coward | more than 4 years ago | (#30187020)

Dom pressed forward against the unfamiliar curve of another man's ass and felt his mouth ...

...mainly about Dom pressing various parts of his anatomy into other people/objects.

At least they don't pollute the city directly (5, Insightful)

jandrese (485) | more than 4 years ago | (#30186974)

There appear to be two primary advanages of these cars: They're cheap to make and they don't directly pollute the city air. If the power plant is downwind they could actually improve the air quality in the city. You also get "free" AC, although heating the car is an issue. Since these are primarily targeted at cities like Mumbai the cooling is more important anyway.

Re:At least they don't pollute the city directly (5, Insightful)

wizardforce (1005805) | more than 4 years ago | (#30187008)

What benefits do these air powered cars have that aren't significantly exceeded by electric vehicles?
The range of these cars is 1/5 of electric cars *and* is less efficient.

Re:At least they don't pollute the city directly (5, Informative)

Sique (173459) | more than 4 years ago | (#30187062)

They were first developed to be used in environments, where sparks could lead to an explosion (e.g. chemical plants or refineries). There you can't use electric cars.

Re:At least they don't pollute the city directly (2, Informative)

DevonBorn (975502) | more than 4 years ago | (#30187292)

Yes you can use electric cars there. AC motors with solid state motor controllers and a hermatically sealed contactor shouldn't generate any sparks.

Re:At least they don't pollute the city directly (3, Informative)

Sique (173459) | more than 4 years ago | (#30187376)

To actually get an asynchronous motor in a car working and to control the speed you need some sophisticated electronics which weren't available when the gas pressure cars were initially developed.

Re:At least they don't pollute the city directly (2, Interesting)

calidoscope (312571) | more than 4 years ago | (#30187638)

Good point, I'd also wonder how much work would be needed to take care of abnormal events with an electric vehicle, e.g. a collision disturbing the integrity of the battery and wiring. This wuld be less of a problem with compressed air.

These were also the same environments that fireless steam locomotives were used in. The hot water stores a lot more energy for a given volume than compressed air.

Re:At least they don't pollute the city directly (2, Insightful)

wizardforce (1005805) | more than 4 years ago | (#30187314)

Yeah but how many people actually need a car that is specifically designed for those kind of environments? They fill a very limited niche that doesn't seem to overlap all that much with most peoples' driving needs. The range is far too short.

Re:At least they don't pollute the city directly (1)

Chris Mattern (191822) | more than 4 years ago | (#30187528)

Whoop-dee-do. The average driver doesn't drive much inside chemical plants or refineries. It's a bust.

Re:At least they don't pollute the city directly (1)

AmigaHeretic (991368) | more than 4 years ago | (#30187064)

What benefits do these air powered cars have that aren't significantly exceeded by electric vehicles? The range of these cars is 1/5 of electric cars *and* is less efficient.

You don't have to strip mine for Lithium. After a few years there are no dead batteries left over to throw away/try to recycle.

Re:At least they don't pollute the city directly (0)

Anonymous Coward | more than 4 years ago | (#30187144)

Lithium isn't strip mined. Water is pumped into salt flats to dissolve the lithium.

Re:At least they don't pollute the city directly (0)

Anonymous Coward | more than 4 years ago | (#30187920)

He's confusing lithium with nickel, which is horribly destructive to mine.

Re:At least they don't pollute the city directly (1)

jandrese (485) | more than 4 years ago | (#30187370)

The very first advantage I listed: They're cheap to make. The biggest barrier to the adoption of electric vehicles has always been the cost of the batteries.

Re:At least they don't pollute the city directly (0)

Anonymous Coward | more than 4 years ago | (#30187566)

Yes they DO pollute the air. Nice piece of misdirection by adding the 'directly', but you're making a very poor argument. They create far more pollution just in the process of compressing the air in the first place than an electric car or even an efficient gasoline powered car, so can the straw man arguments. Do you by chance own stock in a company that wants to market air cars?

Re:At least they don't pollute the city directly (2, Insightful)

Jeremy Erwin (2054) | more than 4 years ago | (#30187646)

To power the air compressors, you'd need more power plants. Many more, since compressed air isn't efficient. Moreover, the compressors themselves would be dirty, so "free A/C" would be unhealthy.

Lets play: Spot The Typo! (0)

Anonymous Coward | more than 4 years ago | (#30186978)

Here's a hint: its one of the words which is a link!

Replace compressed air with compressed hydrogen (1)

commodore64_love (1445365) | more than 4 years ago | (#30186990)

Problem solved. Now you not only get energy from the potential energy of the compression, but also from the fuel itself.

Re:Replace compressed air with compressed hydrogen (1, Insightful)

Anonymous Coward | more than 4 years ago | (#30187032)

Perfect idea, we could use more highly flammable compressed material waiting to explode into a fiery ball of death on the roadways.

Zero Emissions are worse?? (2, Insightful)

AmigaHeretic (991368) | more than 4 years ago | (#30187018)

and despite appearing green the vehicles are worse for the environment

Compressed air is just a medium in which to store energy. The energy could come from solar panels on your garage. It compresses the air. The air powers you car. Zero emitions.

This is opposed to batteries which really aren't good for the environment, but all those Prius owners don't really seem to care about Lithum strip mines while patting themselves on their backs.

Hydrogen is yet another method of storing energy.

Just compressing air from solar, wind power, etc gives Zero emissions no matter if the efficiency is only 1% or 100%

Re:Zero Emissions are worse?? (4, Insightful)

Gerafix (1028986) | more than 4 years ago | (#30187100)

Bullshit. There's no such thing as zero emissions unless you're knee deep in shit in the middle of the wilderness, burning wood for heat. Killing wild animals with your bare hands or tools you hobbled together yourself. Living in a hut made of shrubs down by the river.

Those solar panels, wind turbines, penis pumps etc had to be manufactured somehow and that manufacturing process creates emissions. "Carbon offsets" is a joke, wake up people! Any emission is an emission.

Re:Zero Emissions are worse?? (5, Funny)

AmigaHeretic (991368) | more than 4 years ago | (#30187136)

"Carbon offsets" is a joke, wake up people! Any emission is an emission.

I hold all my farts in sir!

Burning wood is not zero emission (0)

Rix (54095) | more than 4 years ago | (#30187194)

It releases quite a bit of carbon.

Re:Burning wood is not zero emission (4, Insightful)

slim-t (578136) | more than 4 years ago | (#30187350)

It releases the carbon that the tree had already taken out of the atmosphere, and the tree that grows in its place will recapture. So the net is zero emission.

As said in great grandparent post, compressed air and hydrogen are energy storage mediums. Wood is the same thing. Trees use solar energy to convert CO2 into carbon. When you burn the wood, you put the CO2 back into the air and get the energy back as heat.

It doesn't matter if we burn the wood for something useful, the trees dies and rots, or the tree is burned in a forest fire: at some point the carbon is coming back out of that tree.

Only if you replace the tree (1)

Rix (54095) | more than 4 years ago | (#30187520)

Human consumption of firewood doesn't generally get replaced, and subsistence human habitation will tend to deforest an area.

Re:Only if you replace the tree (1)

Gerafix (1028986) | more than 4 years ago | (#30187712)

Yeah wood is probably not the best idea. Hemp would probably be your best bet. Grows faster than flies on shit and is multipurpose.

Re:Zero Emissions are worse?? (1)

OnePumpChump (1560417) | more than 4 years ago | (#30187212)

Burning wood for heat produces a LOT of particulate emissions.

Re:Zero Emissions are worse?? (1)

Devout_IPUite (1284636) | more than 4 years ago | (#30187448)

How long do those stay in the air?

Re:Zero Emissions are worse?? (1)

Overzeetop (214511) | more than 4 years ago | (#30187796)

The CO2 stays in the air until they're absorbed by the trees which his children will burn for firewood. Not really ideal from an immediate perspective, but better than the coal cycle (which requires quite a few generations to become coal again). :-)

Re:Zero Emissions are worse?? (1)

catmistake (814204) | more than 4 years ago | (#30187678)

Any emission is an emission.

Including those of the nocturnal and manual variety... slashdotters, I'm directing this at you. Your body is NOT an amusement park.

Re:Zero Emissions are worse?? (1)

mrboyd (1211932) | more than 4 years ago | (#30187110)

Just compressing air from solar, wind power, etc gives Zero emissions no matter if the efficiency is only 1% or 100%

Well it does matter if we need to cover 3 football field with solar panel for every person who wants to commute in an air car. We're going to run out of space. Anyway, 2010 is around the corner and my flying car running on recycled garbage should theoretically be available shortly.

Re:Zero Emissions are worse?? (5, Informative)

commodore64_love (1445365) | more than 4 years ago | (#30187116)

>>>all those Prius owners don't really seem to care about Lithum strip mines

Prius cars don't use lithium. They use nickle and hydride, and when disposed are no more harmful than throwing-away coins and water. (Although recycling the metal would be better.)

Re:Zero Emissions are worse?? (1)

Rockoon (1252108) | more than 4 years ago | (#30187278)

Nickel and water eh?

Do realize that nickel is toxic to marine life?

Re:Zero Emissions are worse?? (0)

Anonymous Coward | more than 4 years ago | (#30187424)

So is oil.

Re:Zero Emissions are worse?? (2, Interesting)

iroll (717924) | more than 4 years ago | (#30187476)

Citation? I did a little googling, and it doesn't appear to be a hot topic by any standard. The biggest problems with nickel seem to be in its production, not its disposal, and I didn't see any references to nickel toxicity itself.

Plus, we're talking about battery disposal here. The odds are much better that they'd be dumped in landfills than that they'd be dumped in rivers, lakes, and oceans. With landfills, you'd be more worried about aquifer pollution, and I didn't see much concern there, either.

Re:Zero Emissions are worse?? (1)

daemonc (145175) | more than 4 years ago | (#30187916)

I'm guessing the parent actually knew that, since he mentioned strip mining, which is the most common way to produce nickel.

Lithium, on the other hand, is extracted from saltwater.

Re:Zero Emissions are worse?? (2, Insightful)

MoellerPlesset2 (1419023) | more than 4 years ago | (#30187142)

<blockquote>Compressed air is just a medium in which to store energy. The energy could come from solar panels on your garage. It compresses the air. The air powers you car. Zero emitions.</blockquote>

It said 'worse for the environment'. Using more energy is worse for the environment and will continue to be until ALL our energy comes from clean sources.

<blockquote>This is opposed to batteries which really aren't good for the environment, but all those Prius owners don't really seem to care about Lithum strip mines while patting themselves on their backs.</blockquote>

A ridiculous argument - As opposed to your air canisters which aren't made out of mined metals at all? Besides which, that's a whole different environmental issue.

<blockquote>Hydrogen is yet another method of storing energy. </blockquote>

And a vastly more efficient one, making this technology pointless.

Re:Zero Emissions are worse?? (0)

ChipMonk (711367) | more than 4 years ago | (#30187830)

Hydrogen is yet another method of storing energy.

And a vastly more efficient one, making this technology pointless.

Uh, no. Hydrogen power is a net loss, due to the greater energy consumed in currently-available hydrogen production methods. Yes, that may change in the future, but for now, even a solar panel on the garage powering an air compressor incurs less energy loss.

Re:Zero Emissions are worse?? (1)

DarkOx (621550) | more than 4 years ago | (#30187262)

Your are correct but its pretty tough though I think possible to get enough energy for transportation out of storage. In general, and this has been known for a long long time, so I am not sure why this is news compressed gas is a poor energy store. I am referring to compressed gas where the recovered energy will be from allowing it to expand not from a fuel gas like liquidated natural gas or something.

Because solar is only so productive if its going to be the input energy for transportation than the storage medium can't be very lossy. It appears at this time that photo-eclectic where the electric of that transaction is either stored in a battery or converted to its final mechanical use immediately via the motor powering your vehicle are likely to be the most practical options.

Re:Zero Emissions are worse?? (1)

russotto (537200) | more than 4 years ago | (#30187286)

This is opposed to batteries which really aren't good for the environment, but all those Prius owners don't really seem to care about Lithum strip mines while patting themselves on their backs.

That's because they know there's no lithium in the Prius batteries.

Re:Zero Emissions are worse?? (0)

Anonymous Coward | more than 4 years ago | (#30187356)

The new Prius station wagon is using them.

Re:Zero Emissions are worse?? (1)

maxume (22995) | more than 4 years ago | (#30187418)

I mostly don't care about lithium strip mines; I like all the things progress has bought me and slapping a solid layer of saran wrap around the planet doesn't seem like a worthwhile trade off.

(The mostly is there because I don't care for wanton destruction, and our needs can often be met in ways that aren't particularly harmful to the 'natural' environment)

Re:Zero Emissions are worse?? (2, Insightful)

Kymermosst (33885) | more than 4 years ago | (#30187330)

Compressed air is just a medium in which to store energy. The energy could come from solar panels on your garage. It compresses the air. The air powers you car. Zero emitions.

Okay, smart guy. Explain to us the zero-emissions process for manufacturing those solar panels, your air compressor, and your air car.

We're waiting.

Re:Zero Emissions are worse?? (4, Funny)

mweather (1089505) | more than 4 years ago | (#30187882)

Easy. Use solar panels to power the factory.

Re:Zero Emissions are worse?? (1)

the_one(2) (1117139) | more than 4 years ago | (#30187914)

It's solar panels all the way down (seriously)

Re:Zero Emissions are worse?? (1)

Gordonjcp (186804) | more than 4 years ago | (#30187640)

The energy could come from solar panels on your garage. It compresses the air.

How big is your garage? A 1kW solar panel is about 2.5m by 1.5m, or about the size of two slightly taller than standard doors. My compressor draws 3kW from an ordinary wall socket, so by the time you add in the inefficiency of the inverter you're probably looking at four such panels - an area 5m by 3m - to comfortably run that. I suspect that my compressor, with its 200-litre receiver that it can get up to about 150psi before the motor starts to struggle, would just not be enough to power this car for very long. Oh, and don't forget that you could only run the compressor during the day, when you probably will want to use the car. If you're going to store the power in a bank of batteries, why not put the batteries in the car?

The "air car" websites seem a little light on specifics, but they don't seem to mention how large the receiver is or what kind of pressure it holds. I'm betting it's very non-trivial to fill that, safely, without consuming a lot of power.

You should use two measures of electric vehicles (4, Interesting)

presidenteloco (659168) | more than 4 years ago | (#30187044)

The significant fact about electric (or hydrogen fuel cell), or electrically compressed air vehicles
is that electricity (and hence hydrogen via electrolysis, or compressed air tanks) can be generated
in all manner of relatively or completely "green" ways, whereas fossil-fuel transportation is
at least presently restricted to getting its fuel by digging up stored carbon from the Earth at
unsustainable rates.

So electric vehicles (or hydrogen fuel cell, or even relatively inefficient compressed air) vehicles,
are stepping stones on the path to a non-GHG producing future energy system.

So the "green-ness" or carbon footprint of these electrically based technologies should be
measured with two separate baselines:

1. What would their carbon footprint be if all electricity was generated with carbon-neutral generation
methods such as wind/solar/geothermal/hydro/wave/nuclear.

2. What is the carbon footprint assuming the US continues to maintain arguably the most carbon-dirty
electrical generating mix in the world.

Measured in this light, it can be seen that the complete issue is changing the electrical power source for the
US, in parallel with adopting one or multiple forms of transportation technology that is electrically based.
Either change without the other does not work. Both are necessary for effective improvement in emissions
reduction of transportation.

Re:You should use two measures of electric vehicle (1)

MoellerPlesset2 (1419023) | more than 4 years ago | (#30187232)

So the "green-ness" or carbon footprint of these electrically based technologies should be measured with two separate baselines:

1. What would their carbon footprint be if all electricity was generated with carbon-neutral generation methods such as wind/solar/geothermal/hydro/wave/nuclear.

No. That's a totally useless basis for comparison. If I can have 'free' energy (from a carbon-footprint POV), then I can propose any old idiotic idea and can label it 'green'. If I get to disregard efficiency, then I might as well sequester CO2 from the air and turn it back into gasoline - giving me a negative carbon footprint. Not a problem if you've no regard for energy efficiency!

Re:You should use two measures of electric vehicle (1)

russotto (537200) | more than 4 years ago | (#30187306)

No. That's a totally useless basis for comparison. If I can have 'free' energy (from a carbon-footprint POV), then I can propose any old idiotic idea and can label it 'green'.

Exactly. For instance, I use the "free energy" to synthesize 2,2,4-trimethylpentane from CO2 and water, then burn the stuff in an ordinary gasoline car.

Re:You should use two measures of electric vehicle (1)

presidenteloco (659168) | more than 4 years ago | (#30187532)

I didn't actually say that efficiency doesn't matter.
Because obviously it impacts the amount of electrical generating capacity you have to build
for a certain amount of transportation utility.

My main point was that assessing the environmental impact of an electrically-based technology
based on today's way of generating the electricity is misleading and shortsighted, especially when
we already have much of the technology we need to shift the electrical generation method. We just
need to make the morally necessary investment in doing it.

For the record, my bet goes with a combination of new battery technologies and ultracapacitors
in the short term, and some hydrogen fuel cell stuff in the longer term.

I guess congratulations are in order (3, Insightful)

MoellerPlesset2 (1419023) | more than 4 years ago | (#30187046)

Not on debunking this, because it's a completely ridiculous idea that anyone who's taken even introductory engineering thermodynamics should be able to debunk. Rather, they should get credit for going the extra mile and actually getting a paper out of the thing (and media attention!).

I mean really. There's perfectly good reasons why we're not using compressed air as a 'fuel', and it's not that we hadn't thought of it. The idea (and applications) have been around since the 19th century.

Re:I guess congratulations are in order (4, Insightful)

bmajik (96670) | more than 4 years ago | (#30187304)

The problem of humanity is one of the capture, storage, and application of energy.

Gasoline is a fantastic medium for energy storage: it's a better battery than any battery we know how to cheaply produce and service, and that's why we use it. But the energy capture function for gasoline [getting the energy into the gasoline] sucks. And the energy dispersal/application of gasoline has some environmentalists pretty upset.

Nature gives us many ways to store energy now and release it later. The chemical combustion of gasoline is one such mechanism. The desire of a compressed gas to push forcefully against its container is another such mechanism. The strong nuclear bindig energy is a particulary potent and pervasive mechanism. The specific heat of water is yet another.

The fundamental mechanisms of energy storage have been known about for a long time. Taken as a complete system to let humanity accomplish some goal, we are concerned with how we capture the energy, how much of it we can store [and at what cost], and how easy it is to get it back out in a form condusive to the sort of work we want to do with it.

As technology changes we must continually re-evaluate the end-to-end story for a particular aqcuisition/storage/application energy cycle. We may find that we are willing to tolerate a 100 fold decrease in energy storage performance for a 200 fold increase in acquisition efficiency and a qualitative improvement in application performance.

For instance, if i live in arizona and i have a sterling-engine powered air compressor that pumps my 50G tank to 100psi after 12 hours of sunlight, and this lets me go about 10 miles with no consumption of anything other than sunlight... I'm interested. If i commute 5 miles each way, I can get to work and back using nothing but solar energy. And unlike with PV panels and electrical batteries, a guy with a pipe threading die and a welder could build refueling system in his garage, out of stuff that has zero environmental impact whatsoever.

I think that's cool. I'm obviously playing fast and loose with the numbers. Since the kJ/m^2 of solar radiation is known at gridsquares all over north america, you could actually make some ballpark efficiency guesses about peices of the process and plug in real numbers to my hypothetical example. Even if reality is 1 mile @ 30mph after 8 hrs of sunlight.. that fits _some_ usage profile.

It used to be that every farm in North Dakota [where I live] had a windmill powering the farm. Then they disappeared and became an anachronism paying homage to a bygone era. Now windmills are dotting the countryside again. It didn't get windier here.

What changed?

The physics of energy capture, storage, and dispersion have always been the same; our efficiency and the context of the problem space continue to change. As such we must constantly re-evaluate what we did in the past against the realities of today.

Re:I guess congratulations are in order (0)

Anonymous Coward | more than 4 years ago | (#30187726)

For instance, if i live in arizona and i have a sterling-engine powered air compressor that pumps my 50G tank to 100psi after 12 hours of sunlight, and this lets me go about 10 miles with no consumption of anything other than sunlight... I'm interested. If i commute 5 miles each way, I can get to work and back using nothing but solar energy.

Or you could walk it.

I have high hopes for my hot air car (0)

Anonymous Coward | more than 4 years ago | (#30187114)

It runs off politicians and lawyers. They seem to be an abundant natural resource that is simply going to waste.

Cold Steam Engine? (3, Interesting)

Banichi (1255242) | more than 4 years ago | (#30187126)

It occurs to me that a compressed air vehicle could be compared to a "cold" steam engine.

Have there been any scientific advances that could make steam engines in general viable for car sized engines?

Re:Cold Steam Engine? (1, Informative)

Anonymous Coward | more than 4 years ago | (#30187720)

Steam engines that run on stored steam were used for almost a hundred years. They were useful for relatively short ranges where burning coal would create a safety hazard. They had a tremendous advantage over smaller vehicles because their volume varied as the cube of their linear dimensions. Scaling them down to automobile size would, therefore, not produce a vehicle with much range.

'Cold' steam engines weren't even that different from regular engines. The steam would stay as steam for a useful amount of time because of a favorable surface area to volume ratio. In fact, almost any regular engine could be operated 'cold'. They were useful where they were necessary but weren't used otherwise.

Re:Cold Steam Engine? (1)

benjamindees (441808) | more than 4 years ago | (#30187824)

Obviously a micro-turbine could be used in a series hybrid fairly easily. A google search turns up a site with a 'prototype', though a combustion turbine and not steam.

Here's a liquid nitrogen powered car:
http://inhouse.unt.edu/index.cfm?commentID=1163 [unt.edu]

Personally I like MIT's 'millimeter' gas turbine engines:
http://thefutureofthings.com/articles/49/engine-on-a-chip.html [thefutureofthings.com]

twice the carbon footprint (1)

nurb432 (527695) | more than 4 years ago | (#30187132)

I didn't realize that nuclear powerplants were a 'carbon' problem. Or windmills, or the liquid salt solar panels on my roof...

However, i do agree that they are dreadfully inefficient. But they are cheap, reliable, and would shine in in-town commutes or grocery runs in the suburbs.

Re:twice the carbon footprint (1)

dr2chase (653338) | more than 4 years ago | (#30187196)

That is, these are the lamest excuse anyone has yet concocted for not riding a bicycle.

compressed air uses (4, Informative)

stimpleton (732392) | more than 4 years ago | (#30187174)

I did an apprenticeship in Motor Mechanics for 4 years when I left school 25 years ago. I recall a question to the tutor back then about compressed air to drive a car. Here was his answer: Compressed air is not good as a primary driving medium, it is only good as a buffer(the storage tank) or where electricity might add risk. Examples being driving air tools in a pit below ground. By its nature, compressed air must pass thru constricted orifices. There is tremendous loss of pressure over distance. I recall our workshop compressor...very different from what you buy at a hardware store. Huge tank, dual motors, each on three phase power. The newbies job was to empty the water and oil traps from the Air Intake system. About 20 litres per day and about 200 mls of oil like fluid(The atmosphere in the workshop back then was a haze of car fumes and dust). We had 4 electric hoists and one compressed air hoist too. The air hoist could lift many times the wieght of the electric.

I think compressed air cars will serve a specialist role, operating in specific roles. Whether there is commercial visbility, I do not know. Aside from the modern buzzword of "Footprint", the technology to compress air is as old as stem and pistons. That wont change. Even on high tech air craft carriers, the landing restraints have huge hoary old compressed air pistons dampenening the jets planes. The tech below deck, keeps the ram clean and applies some lubricant periodically....just as would happen in steam train days.

oooooo science says its true, must be (-1, Troll)

Anonymous Coward | more than 4 years ago | (#30187204)

Science, religion, what's the difference, it both requires faith to believe in the world they propose.
How strange that every green technology has some american scientific with research "proving" that trees are dangerous to the environement, that gasoline is green, that coal is clean, that unpolluted water will affect the ocean population that air cars are worst than gasoline cars...

Science will be used by anyone to try an convince you off any bullshit they want, if you forget details, discard information you will come to any conclusion, like this one.

Of course data manipulation NEVER happens in science
like this article point out pretty well [examiner.com]

especially not regarding climate change or fuel...

Science is a process to get toward knowing (1)

presidenteloco (659168) | more than 4 years ago | (#30187362)

Science like anything else powerful, will be abused and distorted by some to gain advantage.

Knowing humans, this might very well happen more often than not.

However, that is not really a criticism of the pure abstract principles that define the
scientific method and process. It's just another valid criticism of human being.
(We are right dishonest greedy bastards a lot of the time.)

Scientific process (and its underlying use of techniques/technologies such as
logic, probability theory, empirical observation, organized critique), is as good a way
as we have of building reliable information.

The most powerful thing about the body of well-accepted scientific knowledge as a whole is
not what it says, but the fact that most of the facts, theorems, and predictions hang together without
logically contradicting each other, and that the sheer number of those facts, theorems and
predictions which work keeps growing and growing, while maintaining overall logical consistency.
That makes scientific knowledge very robust, and, justifiably, very hard to assail. Yes, there is
a churn at the edges, and new paradigms, but they are all pretty well structured and well tested
models of reality by the time they become well accepted science. Remember that Newton was not
fundamentally wrong in his physics. He was just able to look at what later turned out to be an important
special case of relativistic physics. And while a few details of Darwin's theories have had to be adjusted
slightly in 150 years, the gist of it is still correct.

There is no other boat in the water that has the potential to systematically
improve the veracity of our information about the world.

Time for a new tagline (5, Funny)

heffrey (229704) | more than 4 years ago | (#30187236)

Slashdot - news for idiots, stuff that's obvious

Re:Time for a new tagline (1)

Hurricane78 (562437) | more than 4 years ago | (#30187592)

You must be new here... ^^

No kidding? (4, Insightful)

Brett Buck (811747) | more than 4 years ago | (#30187250)

This is a surprise to someone? Who ever though this *could* work? Certainly not anyone with any knowledge of thermodynamics. The only compressed -gas systems that even have a chance of working are those that store the working fluid as a liquid, meaning it has to be able to be liquified at room temperature at a reasonable pressure (few hundred PSI at most). Otherwise the tanks are huge and heavy (meaning it will barely move under power) or they are small and heavy (meaning it has no range). Two excellent working fluid for this purpose are - wait for it - CO2 and Freon! Oops.

          Brett

Re:No kidding? (1)

hitmark (640295) | more than 4 years ago | (#30187926)

if one really look into thermodynamics, one can just as well sit down and wait for the universe to die...

There are other ways to compress the air. (3, Interesting)

jcr (53032) | more than 4 years ago | (#30187254)

Compressing air can be done with any source of mechanical energy. Put a windmill on your roof, gear it down, and have it drive the compressor directly.

Come to think of it, having a sizable amount of compressed air storage in one's house would be handy. Great for dusting.

-jcr

Re:There are other ways to compress the air. (2, Insightful)

WaXHeLL (452463) | more than 4 years ago | (#30187346)

Sounds like a tech geek's way of looking at it.

Most people would say -- having a sizable amount of compressed air storage in one's house is great all around -- for your pneumatic power tools.

Re:There are other ways to compress the air. (4, Insightful)

Cyberllama (113628) | more than 4 years ago | (#30187704)

But you could just as easily have that windmill power a turbine to generate electricity to charge the battery in your electric car and get a far higher energy density leading to more mileage per charge and per each day's wind. I think that's the point that's being made. There's lots of clean ways that can generate energy -- any of which can be used to compress air, but why add that extra unnecessary step in the middle when it's just an added inefficiency?

Simple Fix? (1)

IonOtter (629215) | more than 4 years ago | (#30187366)

1. Install windmills at the recharge stations.

2. Place compressors inside the turbine housing instead of electrical generators.

3. Install large storage tanks at the recharge station.

4. Let windmill run for a few days to build up a decent head and some reserve, then use electric compressors to compensate for low-production days.

You can even price compressed air based on production? On calm days, it's more expensive, on windy days it's cheaper.

So I Guess all the Talk (0)

Anonymous Coward | more than 4 years ago | (#30187392)

So I guess all the talk was just a lot of hot air!

Thank you, thank you, I'll be here all week.

Early prototype (1)

noidentity (188756) | more than 4 years ago | (#30187412)

I remember early prototypes of this when I was a kid, called Air Jammers [virtualtoychest.com] . You'd pump them up, then give them a push and a one-cylinder engine would move them along. Of course being a budding Slashdotter, I removed the air motor and connected it to a can of Freon (when you could still buy it) and made it really run fast.

No (0)

Anonymous Coward | more than 4 years ago | (#30187504)

duh.

Thanks Berkeley.

Bad science marketed to unscientific people (1)

macraig (621737) | more than 4 years ago | (#30187542)

Ummm... duh? The marketing for these vehicles was never targeted at physics professors, was it? The people behind it targeted the market that they knew would be vulnerable to the pitch: people who don't "know science" and understand the constraints of the physical world.

I had an unscientific (and religion-spewing) friend get all excited when he heard about these, and tried to infect me with his excitement. I firmly declined. I recognized what he was too delusional to see, that there was nothing at all sustainable about it, that it was merely shifting the unsustainability to make it less obvious to the consumer.

Re:Bad science marketed to unscientific people (1)

Overzeetop (214511) | more than 4 years ago | (#30187860)

Yes, but now there's a white paper from a recognized university (one which has a name associated with greeness) that you can point them to. Let them know that the Tata they have been reading about in Popular Science won't really get 1000 mile on a tank of air* like the marketing information would have them believe.

*and 8-10 gallons of gasoline

New Burrito car (0)

Anonymous Coward | more than 4 years ago | (#30187580)

I'm driving the new burrito powered car, sponsored by Taco Bell. That's right; it has two stages and a storage system. It's called the iFart. It's even got air breaks or breaking wind or whatever. Built in wipers too. You kind of need them for the sharts.

Aircars and electric cars (2, Informative)

zogger (617870) | more than 4 years ago | (#30187670)

These are designed to remove the *concentration* of exhaust gases from fuel burning from crowded urban areas. It isn't really that there are that much less overall emissions, just relocate where the emissions occur (although something can be said for having emissions controls at the generating plant). There's a lot of stop and go traffic, etc, most vehicles today sit at idle or run at some lower less efficient speed in city traffic. Air cars and electric cars shut completely off at "idle" and aren't wasting fuel sitting there in some traffic jam or at the stop light doing nothing as regards moving from point A to B.

That's the primary advantage here for short range urban vehicles as regards the environment. If you primarily do long trips, get a well tuned/ well built modern diesel for best mileage/less fuel burnt.

Nice graphic on this page that shows where the fuel goes with a regular car, idling accounts for almost 1/5th energy wastage today, with extra pollution concentrated then for no real reason.

http://www.fueleconomy.gov/FEG/atv.shtml [fueleconomy.gov]

Bogusity not noticed soon enough. (1)

Animats (122034) | more than 4 years ago | (#30187732)

What bothers me is that the "air car" guy got so much attention for so long. This thing has been in development since 1991, "close to production" since 2003, and the guy has been able to get enough money to build multiple good-looking prototypes. It's starting to look like a long-running scam like the Keely motor or the Moller flying car. The thermodynamics just don't make sense.

In the only publicized test, the vehicle had a range of 7.22 km.

Much is made of the connection between these guys and Tata, the Indian car company. But from IEEE Spectrum, it turns out that Tata's "deal" is that that they just have an option to buy into the technology if it ever works.

The Nantes Tramway [tramwayinfo.com] had compressed-air street cars working in 1911. They ran 6km on flat ground between compressor stations, so their range was comparable to the "air car". They used about 15 pounds of coal (at the compressor stations) per mile, which is roughly equivalent to 1.5 MPG. A typical Diesel bus today gets 6 MPG.

This guy should team up with Molitor (1)

Overzeetop (214511) | more than 4 years ago | (#30187888)

Actually, they shouldn't team up - unless I get a cut of the funds raised. Those two seem to have pulled off one of the greatest money making schemes of all time. Together, they might approach Wall Street levels of shysterism.

So are plug-in hybrids (1)

Orion Blastar (457579) | more than 4 years ago | (#30187774)

unless you use solar or wind power for the electricity you will be using mostly coal burned electrical power. But nobody talks bad about hybrids. Actually my economy car costs less and uses less gas than a hybrid and is more friendly to the environment than a plug-in hybrid unless they are using renewable green electricity to power the plug-in hybrid.

I think the car that ran on used french fry oil was the best idea yet, but once that catches on fast food places will charge a lot for used french fry oil.

The ONLY efficient one will be electric (1)

WindBourne (631190) | more than 4 years ago | (#30187810)

The simple fact is, that electric cars are by far the only efficient means of moving. The ONLY real issue is the storage. Once that is licked (and great strides have been made over the last 15 years), then it is over for idea like the air car, gas cars, or even hydrogen.

What about Air hybrids? (0)

Anonymous Coward | more than 4 years ago | (#30187904)

Did I miss it, or did this not cover engines like the Scuderi air hybrid?

Hot Air (1)

iliketrash (624051) | more than 4 years ago | (#30187910)

"Air cars are an enchanting idea, providing mobility with zero fuel consumption or environmental impacts."

Yeah, right. We'll get our American politicians to engage with those pesky air molecules in order to get them to crowd together for zero cost and with no carbon emissions.

Twice the carbon - in the US maybe (1)

vik (17857) | more than 4 years ago | (#30187918)

The US produces 80% of its power from fossil fuels, and the cars are twice as bad as burning fossil fuel direct. BUT in more enlightened places 70% of the power is from renewables, so only 30% can be from fossil fuels max. So the production of compressed air is over twice as efficient, and these vehicles start to make sense. Said country (take New Zealand as an example) doesn't need to import massive quantities of expensive batteries to power the cars. Beware US-centric energy statistics; they only apply to a tiny fraction of the world's population.

Its all about energy density (1)

cheesybagel (670288) | more than 4 years ago | (#30187934)

No kidding compressed air is crap for automobiles.When something manages to have worse volumetric energy density [xtronics.com] than lead acid batteries, plus nearly as bad gravimetric energy density even when you aren't factoring the weight of the container vessel, you know you have a loser there.

Load More Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>