Algae oil.

[naval_aviator_2040]

we should go back to steam powered cars. steam engines can run just as well on biofuels as they can on petroleum products and even when they do use petroleum fuels the environmental impact is less than internal combustion engines using the same grade of fuels. in the twenties the doble steam motors company produced a model that could start almost instantly in any weather, and could accelerate from 0-75 miles/hour in 10 seconds. that particular model ran on kerosene but the priciple is the same with diesel and with the advent of steam turbines in later years i think that the advantage of using kerosene would have been overcome anyway.

Also, there is a particular type of External Combustion Engine (Steam) called the Sterling Engine that has been used with significant success by the Swedish navy since 1988.

[Martin Blank]

Stirling engines are very efficient, but not very good for personal transportation. The Swedish navy uses them in subs, which need to be quiet (something Stirling engines are good at), but they are a supplement to the existing diesel engines. They are used during extended underwater runs, which would normally drain the batteries.

[naval_aviator_2040]

true but it's a good way to show that external combustion is still a viable technology. My School's training ship still uses steam turbines for both propulsion and for power generation

[Beware of the Leopard]

First, I wanted to apologize to Adciv. I didn't have any basis for thinking you were being dismissive in your post and I countered it hypocritically by being dismissive of your arguement, if, in fact, it was an arguement in the first place.

Here's how my response should have been if I was not in a crap mood that day:

The scale does seem daunting until you put it in perspective with what is actually happening already. This article from Time magazine is quite illuminating about the problem with current biofuel sources:
http://www.time.com/time/magazine/artic ... 75,00.html

Interestingly, since someone was using Rhode Island as a scale comparison earlier in this thread...
"This destructive biofuel dynamic is on vivid display in Brazil, where a Rhode Island--size chunk of the Amazon was deforested in the second half of 2007 and even more was degraded by fire."

So, from a land usage perspective, if you can believe the previously quoted production level per acre of land, algae could be a sustainable alternative to other biofuels.

[adciv]

we should go back to steam powered cars. steam engines can run just as well on biofuels as they can on petroleum products and even when they do use petroleum fuels the environmental impact is less than internal combustion engines using the same grade of fuels.

Ok, I'm calling BS on this. In order for a steam engine to run, you have to heat up your water supply to the boiling temeprature. Unless you are keeping it at near boiling all the time, you are not going to have an instant on car. Further, if steam is so much better, it would still be in use by the railroads instead of the disel-electric trains in use today.

[Beware of the Leopard]

Although I'm not advocating a steam vehicle by any means, you could get an instant start if it were a steam/electric hybrid. The usefulness would depend on whether or not the heat engine+water is greater than or less than the weight difference between the battery you would need for start-up vs. the battery you would need for a simple plug in electric.

Also, when you're nearing 88 miles per hour, the boiler explodes! </awesome reference>

[Deacon]

Steam is not a source of energy. You need an energy source to create the steam to create the electricity (or even worse the mechanical locomotion).

[adciv]

Although I'm not advocating a steam vehicle by any means, you could get an instant start if it were a steam/electric hybrid.

in the twenties the doble steam motors company produced a model that could start almost instantly in any weather

I doubt those existed in the twenties.

[Beware of the Leopard]

Corrected... since you're being nitpicky about wording... :p

Water is not a source of energy. You need an energy source to create the steam to create the electricity (or even worse the mechanical locomotion).

I don't think anyone was saying that. I assumed someone was trying to advocate a heat engine as a more efficient use of any heat generating fuel than internal combustion. Steam power, although a scientifically incorrect phrase, is simply a historical convention like electric current going from positive to negative. A horse is not the energy source for a horse drawn carriage, either.

I would need some research to convince me. The train arguement is not a good one as diesel may simply give better hp at the expense of efficiency. I could counter this statement with the fact that power plants do not use internal combustion. This isn't a cut and dry situation where one can hand-wave-logic one or the other out. My gut tells me that steam isn't a good idea for a personal vehicle simply because it seems to have already been ruled out, but the rise of hybrids makes me think it needs another shot... on paper at the least.

(cool, these newfangled forums alert me to ninjas when submitting)
How did the one in the 20's work? They did have electric motors at the time. If it was straight up mechanical, they may have been able to bring the water to an instant boil with high surface area, but still... there had to be some time to get the heat to the water. (I suppose that's the "almost")

[naval_aviator_2040]

http://www.catskillarchive.com/rrextra/automo.Html

read the section about starting steam engines

http://www.popularmechanics.com/automot ... tml?page=1

direct testimony from a knowlegable (if not technically expert) author published in a respected mechanical periodical

[supra]

despite all of these ideas, any thermal cycle is limited to carnot efficiency (which can be calculated by eta = 1 - Tl/Th). the only way to get around this is to not use heat as the primary energy medium. this can be accomplished through the use of electricity (it has a higher exergy value than heat even at the same energy value)... which is precisely why fuel cells are getting so much attention. because they oxidize the fuel in an electrical process (instead of combusting it), they are not limited by carnot and can approach 85% efficiency.

[Deacon]

Corrected... since you're being nitpicky about wording... :p

Steam is water.

Also, bear in mind regarding your musings about trains and such that engines do not necessarily scale the same way. If you take a 3.0 liter engine and just enlarge it in AutoCAD to 6.0L, you don't necessarily get twice the power and equal efficiency (or half efficiency for that matter), etc.

[naval_aviator_2040]

I don't disagree with that i just feel that it would be simpler, technilogically speaking, to to use steam cars as a temporary stop gap against pollution until such time as things like hydrogen and other alternative fuels are ready for large-scale implementation. Do I seriously beleive that this will happen? noi do not. There's almost no popular support for it and people still think of steam power as an outmoded means of transportation, even though all nuclear power is actually steam being generated by the heat of a nuclear reaction.

[Deacon]

i just feel that it would be simpler, technilogically speaking, to to use steam cars as a temporary stop gap against pollution

WHERE IS THE STEAM GETTING ITS HEAT FROM?? And how would adding an additional mechanical middle-man increase efficiency? You don't explain yourself.

all nuclear power is actually steam being generated by the heat of a nuclear reaction.

OK, awesome, we'll all move to have nuclear reactors under our respective hoods.

[naval_aviator_2040]

the steam would be generated by burning fuels like fossil fuels or bio fuels I'm pretty sure i was clear about that. as for efficiency its like this, The high pressure steam acts DIRECTLY on the drive wheels and the speed can be controlled by a simple throttle vavle which controlls the amount of steam let into the engine which eliminates the need for a complicated drive shaft and transmission system

EDIT* as for fuel efficiency, the burner on a boiler atomises the fuel much more efficiently than a standard carburator so the fuel burns cleaner and more efficiently

and of course i didn't mean that we should have nuclear reactors in our cars i was using nuclear power as an example of how steam is still in relatively widespread use today.