First viable compressed air car: get 200-300km per tank of air. • Hacker News Board

Re: First viable compressed air car: get 200-300km per tank of air.

#11

Post by olefoo » Fri, Jun 20, 2008, 2:59 PM UTC

mynameishere wrote: post #9

elad wrote: post #3

Earlier quoted context omitted.

Maybe part of the explanation is that it's very light-weight - the car in the photo looks tiny, it says it's made of fiberglass, and my guess is that the engine must also weigh much less than a comparable internal combustion engine (you don't need as much metal to contain the combustion...). Of course, that probably comes with a heavy price to passenger safety. Fiberglass won't give you any protection in a crush. Tha…

Fiberglass won't give you any protection in a crush Damn, just put the tank of air in front. Any wreck will cause a mighty explosion balancing out the various vectors involved. I haven't done (and couldn't do, really) the math, but this seems perfectly reasonable.

Or use the compressed air to fill a whole vehicle airbag that triggers on items on a collision path.

This would mean that your safety systems are highly dependent on software and effective sensors, but hey, cheap car.

Re: First viable compressed air car: get 200-300km per tank of air.

#12

Post by tx » Fri, Jun 20, 2008, 4:43 PM UTC

asp742 wrote: post #7

tx wrote: post #5

Ok, we won't be burning gasoline in a vehicle, we'll be burning it to compress air when refueling. For similar reasons I don't get the fuss about electric "zero-emission" cars. Zero? Like electricity just magically comes out of nowhere...

It's like software. If you cleanly separate the front-end and back-end it's very easy to tune and swap out the back-end without the user noticing.

Like your analogy! :) The bigger picture is that we're approaching an energy crisis. That's why gas is getting more expensive, and that is why there is even an interest in these cars to begin with: the message isn't to "separate front end and back end" but to appeal to people who want to save money on energy costs, i.e. gasoline. But it won't work, because gasoline is just the medium, the real beef here is energy, and it's not going to get cheaper because we need more and more of it. It's not only gasoline that's getting expensive, my gas and electric bills are ahead of inflation as well.

"Solutions" covered by the press aren't really solving the problem, they're just shifting it around. "Wow! We have an air-powered car!" - without an explanation where the energy to compress that air is going to come from...

Re: First viable compressed air car: get 200-300km per tank of air.

#13

Post by tx » Fri, Jun 20, 2008, 4:53 PM UTC

smanek wrote: post #2

Compressed air has great power density, but awful energy density. I.e., you can unload power very quickly from it but can't store much at all. Looking at this http://www.popularmechanics.com/automotive/new_cars/4217016.... popular mechanics article, this engine uses 340 Liters of air (under STP) compressed at 4350 PSI. If my math is right, that only provides a theoretical maximum of about 55 MJ of energy, which is ab…

I suspect you're underestimating efficiency of both types of engines. Diesels, for instance, are always above 30% and air-compressed should be a lot higher: they don't have an enormous energy loss in a form of heat compared to diesels.

Re: First viable compressed air car: get 200-300km per tank of air.

#14

Post by jcl » Fri, Jun 20, 2008, 5:24 PM UTC

tx wrote: post #12

asp742 wrote: post #7

Earlier quoted context omitted.

It's like software. If you cleanly separate the front-end and back-end it's very easy to tune and swap out the back-end without the user noticing.

Like your analogy! :) The bigger picture is that we're approaching an energy crisis. That's why gas is getting more expensive, and that is why there is even an interest in these cars to begin with: the message isn't to "separate front end and back end" but to appeal to people who want to save money on energy costs , i.e. gasoline. But it won't work, because gasoline is just the medium, the real beef here is energy, a…

If you assume the problem is "Where will we find energy to sustain our current consumption rate?", then you're right: air-cars aren't a solution. Such a solution might not even exist.

But if you assume the problem is "How can we relieve market pressure on our most constrained resource?", air and electric cars are a solution. The hope is that by diversifying the sources of energy used for transportation, we can continue to use oil for other purposes that we haven't found cost-effective replacements for yet -- like plastics and jet fuel.

So while the cars won't solve the energy crisis by themselves, maybe they'll buy us enough time to reach the "then a miracle occurs" discovery that does solve it. Or, failing that, maybe they'll help civilization make a slow transition to reduced consumption, rather than a sharp crash.

Re: First viable compressed air car: get 200-300km per tank of air.

#15

Post by run4yourlives » Fri, Jun 20, 2008, 5:54 PM UTC

tx wrote: post #5

Ok, we won't be burning gasoline in a vehicle, we'll be burning it to compress air when refueling. For similar reasons I don't get the fuss about electric "zero-emission" cars. Zero? Like electricity just magically comes out of nowhere...

Not all of us burn stuff to make electricity. In BC, all our power is hydro.

Re: First viable compressed air car: get 200-300km per tank of air.

#16

Post by khafra » Fri, Jun 20, 2008, 6:36 PM UTC

jcl wrote: post #14

tx wrote: post #12

Earlier quoted context omitted.

Like your analogy! :) The bigger picture is that we're approaching an energy crisis. That's why gas is getting more expensive, and that is why there is even an interest in these cars to begin with: the message isn't to "separate front end and back end" but to appeal to people who want to save money on energy costs , i.e. gasoline. But it won't work, because gasoline is just the medium, the real beef here is energy, a…

If you assume the problem is "Where will we find energy to sustain our current consumption rate?", then you're right: air-cars aren't a solution. Such a solution might not even exist. But if you assume the problem is "How can we relieve market pressure on our most constrained resource?", air and electric cars are a solution. The hope is that by diversifying the sources of energy used for transportation, we can contin…

Materials science needs to get on the ball and invent Adamantium, from Marvel Comics. Then we can have compressed air-powered airliners.

Re: First viable compressed air car: get 200-300km per tank of air.

#17

Post by rw » Fri, Jun 20, 2008, 7:13 PM UTC

run4yourlives wrote: post #15

tx wrote: post #5

Ok, we won't be burning gasoline in a vehicle, we'll be burning it to compress air when refueling. For similar reasons I don't get the fuss about electric "zero-emission" cars. Zero? Like electricity just magically comes out of nowhere...

Not all of us burn stuff to make electricity. In BC, all our power is hydro.

What we don't need are more dams in our waterways.

Re: First viable compressed air car: get 200-300km per tank of air.

#18

Post by run4yourlives » Fri, Jun 20, 2008, 7:17 PM UTC

rw wrote: post #17

run4yourlives wrote: post #15

Earlier quoted context omitted.

Not all of us burn stuff to make electricity. In BC, all our power is hydro.

What we don't need are more dams in our waterways.

Well, you can always live with the lights off then. Given what's currently possible, dams are the best solution to this problem out there.

Re: First viable compressed air car: get 200-300km per tank of air.

#19

Post by elad » Sat, Jun 21, 2008, 8:47 AM UTC

olefoo wrote: post #11

mynameishere wrote: post #9

Earlier quoted context omitted.

Fiberglass won't give you any protection in a crush Damn, just put the tank of air in front. Any wreck will cause a mighty explosion balancing out the various vectors involved. I haven't done (and couldn't do, really) the math, but this seems perfectly reasonable.

Or use the compressed air to fill a whole vehicle airbag that triggers on items on a collision path. This would mean that your safety systems are highly dependent on software and effective sensors, but hey, cheap car.

It would also mean that your level of protection depends on the amount of air in your tank.

As someone who chronically forgets to fill-up, I wouldn't like that idea...