Alternative ways to power vehicles.

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*GC*
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Alternative ways to power vehicles.

Postby *GC* » Thu Feb 12, 2009 4:52 am UTC

I have been thinking a lot about this issue, between the "green" movement, new fuel technology, ect.

Now I am probably in lowest 20% IQ wise of the posters on this board so I fully expect a quick easy answer to why this idea cannot possibly work. And here it is.
By-products of using cars seem to produce quite a bit of unused energy. Tires spin around metal rims, can we not harness and transfer some of this energy back into the vehicle? While in motion the vehicle faces wind resistance, currently we use that as a way to bring air in to mix with fuel, could we not also install small wind turbines to convert this kinetic energy into mechanical energy?

I'm not saying this could self power entire vehicles, but at least for electric cars couldn't this make the batteries last much longer between plug ins, with the bonus of being neutral energy that has just been being wasted for decades?

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Re: Alternative ways to power vehicles.

Postby Bobbias » Thu Feb 12, 2009 5:01 am UTC

I've wondered about things like this myself.

However, I'm not sure if you're aware of the one system I know is being included in some prototype (if not production model) electric cars. It's called Regenerative Braking. The system basically reverses the entire drive system and runs the motor backwards, so that it acts as a generator and recharges the battery. Instead of using the traditional brake pads, which as you may know, waste HUGE amounts of energy (other than wind resistance, and other factors, they dissipate the entire momentum when stopping a car, and that is quite a bit of energy), they essentially use the resistance of the motor-turned-generator to stop the car, recovering much of that braking energy as electrical energy to recharge the battery.

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Re: Alternative ways to power vehicles.

Postby Malice » Thu Feb 12, 2009 5:06 am UTC

*GC* wrote:I have been thinking a lot about this issue, between the "green" movement, new fuel technology, ect.

Now I am probably in lowest 20% IQ wise of the posters on this board so I fully expect a quick easy answer to why this idea cannot possibly work. And here it is.
By-products of using cars seem to produce quite a bit of unused energy. Tires spin around metal rims, can we not harness and transfer some of this energy back into the vehicle? While in motion the vehicle faces wind resistance, currently we use that as a way to bring air in to mix with fuel, could we not also install small wind turbines to convert this kinetic energy into mechanical energy?

I'm not saying this could self power entire vehicles, but at least for electric cars couldn't this make the batteries last much longer between plug ins, with the bonus of being neutral energy that has just been being wasted for decades?


Yeah, this couldn't actually self-power a vehicle, but it might make them more efficient. The question being, efficient enough to be worth it?
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Re: Alternative ways to power vehicles.

Postby heydonms » Thu Feb 12, 2009 7:48 am UTC

Malice wrote:efficient enough to be worth it?


I think this is the downfall of the idea, the benefits are just too small to justify the cost. The equipment required to obtain energy from the slipping of a tyre on a rim would increase weight and probably mess up balance (requiring more weight to counteract it) while the energy obtained would be minimal.

Turbines generating energy would increase drag and you would just wind up having to push harder to make up for their presence. If you could deploy the turbines while breaking and retract them while accelerating and cruising then it might work, but you would probably find it easier to work on improving the efficiency of existing regenerative breaking systems and reducing drag.

A better target for recovering waste energy might be a house where weight and bulk are less of an issue.

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Re: Alternative ways to power vehicles.

Postby JBJ » Thu Feb 12, 2009 1:06 pm UTC

As stated already, the car is expending energy to move. By placing additional load on the tires, or increasing drag with turbines, it takes more energy to maintain speed than the energy benefits by recouping the energy of the rotating tires or the turbines. And as also stated, you could capture some of that energy when braking, but the additional weight and complexity of those systems makes it impractical for most cars. Many electric cars do have regenerative braking, but for a traditional gasoline car it wouldn't be much benefit, if at all.

All the energy of a car is derived from the fuel (gas or diesel). Most of that energy is lost as heat. Only 18-20% of the energyof the fuel is transformed to actual work. If you could capture some of that lost heat and transform it into energy then you'd be onto something. Maybe have some thermocouples to supplement some of the electrical systems?

Edit: thought of this after I posted...
Since efficiency in cars is typically measured as fuel economy (mpg), you can also realize benefits simply by changing some driving habits. There are also hypermiling techniques that can improve your mileage. Some of these techniques are controversial or even dangerous such as drafting close to semis, but most are just common sense, such as not driving aggressively and maintaining your vehicle properly.
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Re: Alternative ways to power vehicles.

Postby phonon266737 » Thu Feb 12, 2009 1:57 pm UTC

Today, there are 2 big roadblocks to fuel economy in cars - weight and marketing

What drags on a car? Air drag, frictional drag, and overcoming inertia.that's about it. So why are cross-sections of late model cars so BIG? and AWD, a popular feature (even the ford fusion!) requires many more bearings and certainly reduces efficiency. Not to metnion, today's china-produced bearings are of lower quality than those used in the 1960's. If you luck out and get one manufactured to high tolerances, that's cool, but the same part number could come from anywhere.

Inertia, on the other hand, equals weight. The Toyota Prius is 3,000 lbs - very impressive considering all the stuff that's in it! (battery along is ~ 130 lb) Cars have been 2-3 thousand pounds for a long time - weight reduction over time is very close to zero - understandable as exotic materials are out of the picture.

So, if we have more air drag, more frictional drag, and equal inertia, all we can do if improve the ICE. (more later)

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Re: Alternative ways to power vehicles.

Postby Azrael » Thu Feb 12, 2009 2:15 pm UTC

phonon266737 wrote:Not to metnion, today's china-produced bearings are of lower quality than those used in the 1960's. If you luck out and get one manufactured to high tolerances, that's cool, but the same part number could come from anywhere.

This is a pretty significant twisting or misunderstanding of manufacturing process.

First, go ask someone who owned and maintained a (domestic) car in the 60's. Wheel bearings were much more frequently replaced, repacked or tightened than they are in modern cars. At this point, wheel bearings along with differentials and transmissions are designed to be a set and forget components. That was not always the case.

Secondly, regardless of where bearings are sourced, car companies have very strict quality control processes at the component level designed to eliminate variance. Because variance costs the manufacturer money. So component to component repeatability is typically quite high.

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Re: Alternative ways to power vehicles.

Postby netcrusher88 » Thu Feb 12, 2009 2:16 pm UTC

Regenerative braking isn't just in production, it's standard procedure. All hybrid platforms and (I believe) all electric platforms use regenerative braking, because the incremental cost to stick it onto an already-electric car is next to zero (compared to what the car already costs...) since all you're doing is hooking up the system so that instead of the motor pushing the wheels, the wheels are pushing the motor, and therefore the benefit is worth it. There's some slightly more complicated things you have to do to get that power to a battery, but it's all details.

*GC* wrote:By-products of using cars seem to produce quite a bit of unused energy. Tires spin around metal rims, can we not harness and transfer some of this energy back into the vehicle? While in motion the vehicle faces wind resistance, currently we use that as a way to bring air in to mix with fuel, could we not also install small wind turbines to convert this kinetic energy into mechanical energy?


I don't follow the bit about tires spinning around metal rims. The tires are in fact fixed to the rims, though I think that "coupling" is only friction, though I've never heard of them slipping. Do you mean the bearings? Either way, any time that you have the motor directly driving a generator (at the same time as it pushes the wheels) you're not going to recover as much energy as would be wasted in the conversion between types of energy, carrying that energy a distance (wires aren't perfect conductors), and the mechanical linkage. It's better to just put as much energy as you can coming out of the motor directly to the road, and try to recover what you can while braking.

As far as wind resistance, as soon as you add turbines or something you increase drag - modern cars are tuned for extremely low drag as-is. I don't think you're going to recover the amount of energy you waste overcoming the added drag with wind turbines.
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Re: Alternative ways to power vehicles.

Postby drunken » Thu Feb 12, 2009 6:41 pm UTC

Air turbines are not going to help for physics reasons. The overall idea behind the Op is however something that is feasible. The idea of using waste energy from a process. The thing is that wind friction is not waste energy, if you dont expend energy overcoming wind friction the car wont move. Realistic examples like regenerative braking are however very much in use and under developement as mentioned earlier. Another recent example is using suspension energy:
http://tech.slashdot.org/article.pl?sid=09/02/12/0253204
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Re: Alternative ways to power vehicles.

Postby *GC* » Thu Feb 12, 2009 8:09 pm UTC

I'm not understanding the significant increase in drag problem with the wind power. I understand it will increase drag somewhat, in my mind they would be very similar to the fans behind the grill in front of the radiator only instead of using power from the battery to spin them they use the 40+ mph wind to spin in turn feeding a generator sending what energy it creates to the battery.

As for the wheels, I'm thinking I may not have explained it well. My idea is placing something like an alternator with at each wheel but instead of a belt spinning it the rotation of the rim would spin it sending power back to the battery.

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Re: Alternative ways to power vehicles.

Postby Azrael » Thu Feb 12, 2009 8:28 pm UTC

That's how regenerative breaking works. Instead of wasting the energy by using the car's breaks to convert kinetic energy into heat, a generator removes that kinetic energy, converting it back to electricity which is then stored in a battery.

But if you do it while the vehicle is moving , you're taking power away from the wheel, preventing motion -- even with perfect efficiency, every watt regenerated would be an extra watt the motor would have to supply in the first place.

The same is true with fans (or the like) mounted externally. Every watt generated would be one extra watt the engine would have to supply, minus losses. As for fans inside the grill, a (very) small amount of energy could probably be captured, at the expense of cooling. So it would have to be a very carefully analyzed trade off -- and probably not even remotely close to worth the expense.

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Re: Alternative ways to power vehicles.

Postby WaterToFire » Thu Feb 12, 2009 11:01 pm UTC

*GC* wrote:I'm not understanding the significant increase in drag problem with the wind power. I understand it will increase drag somewhat, in my mind they would be very similar to the fans behind the grill in front of the radiator only instead of using power from the battery to spin them they use the 40+ mph wind to spin in turn feeding a generator sending what energy it creates to the battery.

The problem is that the energy of the wind that you'd be sapping off from is actually already in use-- it's not waste energy, like the heat is. The energy of the wind's inertia all comes from pushing the car through the air, and so if you steal that energy, you end up with less energy pushing the car forward. If you had 100% efficiency you'd still end up with exactly the energy you started with, but you don't, so you'd really be wasting energy every time those turbines spun.

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Re: Alternative ways to power vehicles.

Postby netcrusher88 » Thu Feb 12, 2009 11:22 pm UTC

WaterToFire wrote:
*GC* wrote:I'm not understanding the significant increase in drag problem with the wind power. I understand it will increase drag somewhat, in my mind they would be very similar to the fans behind the grill in front of the radiator only instead of using power from the battery to spin them they use the 40+ mph wind to spin in turn feeding a generator sending what energy it creates to the battery.

The problem is that the energy of the wind that you'd be sapping off from is actually already in use-- it's not waste energy, like the heat is. The energy of the wind's inertia all comes from pushing the car through the air, and so if you steal that energy, you end up with less energy pushing the car forward. If you had 100% efficiency you'd still end up with exactly the energy you started with, but you don't, so you'd really be wasting energy every time those turbines spun.

Incidentally this same point works for your other idea:
*GC* wrote:As for the wheels, I'm thinking I may not have explained it well. My idea is placing something like an alternator with at each wheel but instead of a belt spinning it the rotation of the rim would spin it sending power back to the battery.

Unless you're talking about freewheeling those alternators except when braking - which is regenerative breaking.

These are nifty ideas, mind, but they fail to account for the fact that efficiency is sub-100%.

Azrael wrote:As for fans inside the grill, a (very) small amount of energy could probably be captured, at the expense of cooling. So it would have to be a very carefully analyzed trade off -- and probably not even remotely close to worth the expense.

Particularly given the fan on the radiator sucks air in already. Though that might not be necessary for electric cars... but then, would a grill be?
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Re: Alternative ways to power vehicles.

Postby vslayer » Fri Feb 13, 2009 12:16 am UTC

i cant seem to find the article, but there was a guy a while back who developed an engine which recouperated its own heat to produce additional power, negating energy loss through both heat production and the cooling systems required in standard engines.

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Re: Alternative ways to power vehicles.

Postby phonon266737 » Fri Feb 13, 2009 1:40 am UTC

Az, I'll give you your point on the wheel bearings - older cars DO need their bearings maintained relatively frequently, and adjuted for wear. My point is that when you set the bearing preload every year (provided it is done by a trained technician), the bearings stay in spec. Modern bearings tend to come from the factory quite tight, "wear" through the sweet spot, and eventually become too loose and in need of replacement. Great from a maintenance and assembly standpoint, but maintenance free is far from the ideal environment of a good high-efficiency bearing.

On the subject of recovery of waste heat, I'm surprised no one has brought up the most ingenious part of the Toyota Prius, IMHO. Through clever valve timing, the engine in the Prius has vastly different compression and expansion ratios (at the expense of peak power). The Prius engine, essentially, goes DOWN 33% farther than it goes up (it goes up the 1/3 stroke too, but no compression , expansion, intaking, or exhausting is occuring - it's just dead movement)
This means the exhaust gas is significantly more "expanded" before it leaves the engine, and has had a great deal more energy removed from it. They also have extrememly high efficienct tires, brakes designed to mitigate dragging, and a myriad of other efficient innovations. I would love to see a Toyota "Prius" base model - without any hybrid synergy drive, battery packs, electric motors, high voltage capacitors, etc etc. I bet it could weigh less than 2,000 lbs and get 50-60 mpg highway.
http://en.wikipedia.org/wiki/Atkinson_cycle

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Re: Alternative ways to power vehicles.

Postby Mabus_Zero » Fri Feb 13, 2009 4:34 am UTC

My personal fantasy in this regard is raw-capacitor driven vehicles, powered from a central grid, thus being ambidextrious to changes in technology, because it consumes a standard, basic form of energy, rather then requiring a chemical fuel. The individual that wishes to keep their own supply of fuel could therefore, forseeably, use solar panels, or even gasoline, if they like, to power the vehicle. All they'd forseeably have to do is have a measure of equipment to harness and store this electrical energy, and then to load it into the reusable capacitors of the vehicle.

The technology has a little ways to go, but the science seems to be there for it already.
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Re: Alternative ways to power vehicles.

Postby Minerva » Fri Feb 13, 2009 5:18 am UTC

Right, regenerative braking is good, but you need an electric vehicle to do it, and essentially every electric vehicle is already doing it.

JBJ wrote:All the energy of a car is derived from the fuel (gas or diesel). Most of that energy is lost as heat. Only 18-20% of the energyof the fuel is transformed to actual work. If you could capture some of that lost heat and transform it into energy then you'd be onto something. Maybe have some thermocouples to supplement some of the electrical systems.


You've got to remember that it's a real engine, and if we could build engines of comparable size, weight, power output and performance with better thermodynamic efficiency, we would already see car manufacturers doing it, but in this house, we obey the laws of thermodynamics.

We already use "cogeneration" extensively in cars to take advantage of the waste heat - that's how car heaters work. That seems to be one of the easiest, most useful things we can practically do with the low grade heat.

It's relatively low grade, low temperature heat, so trying to do anything with it, especially using systems that have to be very compact and relatively lightweight, is hard. Trying to use Seebeck-effect devices to generate current from the waste heat would just be prohibitively expensive for a tiny amount of energy harnessed.
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Re: Alternative ways to power vehicles.

Postby Hawknc » Fri Feb 13, 2009 7:12 am UTC

That said, waste energy from the engine can be used pretty effectively to reduce emissions and fuel consumption. Exhaust gas recirculation can boost thermal efficiency by redirecting a small amount of exhaust gases back through the intake into the cylinder to mix with the air and fuel. Turbochargers are becoming much more common as a method of reducing engine size while maintaining power output, and work by using exhaust gases to drive a turbine, which forces air into the cylinders at a higher pressure. (Expect to see many, many more of these as companies downsize from V8s and V6s to boosted V6s and I4s, respectively.)
phonon266737 wrote:Az, I'll give you your point on the wheel bearings - older cars DO need their bearings maintained relatively frequently, and adjuted for wear. My point is that when you set the bearing preload every year (provided it is done by a trained technician), the bearings stay in spec. Modern bearings tend to come from the factory quite tight, "wear" through the sweet spot, and eventually become too loose and in need of replacement. Great from a maintenance and assembly standpoint, but maintenance free is far from the ideal environment of a good high-efficiency bearing.

Fair. Tell you what, you let me know how much more you're willing to drop for a car, and I'll let you know how much we can increase reliability. ;) Everyone disses cost-cutting measures, but it's not like we're making much money on the damn things these days and customers sure as hell don't want to pay more money for them. And all components have to meet reliability specs set by the car manufacturer - if they're not up to scratch, the suppliers risk losing hundreds of millions of dollars of business when the car company sources them from somewhere else.

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Re: Alternative ways to power vehicles.

Postby phonon266737 » Fri Feb 13, 2009 6:13 pm UTC

Tell you what, you let me know how much more you're willing to drop for a car, and I'll let you know how much we can increase reliability. Everyone disses cost-cutting measures, but it's not like we're making much money on the damn things these days and customers sure as hell don't want to pay more money for them.


Good point, and it applies to this entire discussion. a lot of more effiecnt stuff can be done in a car (the 40% efficient two-stroke turbocharged diesel comes to mind) but until customers are planning on purchasing vehicles for more than 3-5 years, it's really hard to do anything.

Look at the economics of a traditional new-car buyer who keeps their car for 3 or 4 years. They take a huge hit on purchase price versus sale price - probably more than the cost of all the fuel they burned in those years. Making a new car more expensive and more efficient simply hits them harder - the economic benefits from fuel efficiency only accumulate when you go for a long time without replacement or major repairs.

[If you ask me, it will all work out. The technology exists, however, it is not cost effecive because of the price of fuel - and the government taxes on fuel are already quite high. Increasing the cost of fuel via taxes to make certain technology cost effective is chasing your own tail, but if the government were to enter the international oil market and buy lots and lots of it, then they could drive prices up WORLDWIDE, not just in our country. But that's not really part of this topic, so I apologize]

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Re: Alternative ways to power vehicles.

Postby juststrange » Fri Feb 13, 2009 8:39 pm UTC

Like it has been stated before, one of the biggest enemies is weight. And the truth is, one of the biggest additions to weight is safety. The Honda CRX HF from the late 80's early 90's weighed less than 2000 pounds from the factory, and got 50+ mpg. That said, it also had no regular airbags, side curtain airbags hadn't even been invented, and the thing would fold up like tin foil in an accident. Add in seatbelt motors, power windows, and all the other comfort stuffs, and todays cars are tanks compared to back then.

How do you feel about alternative IC engines - i.e. Wankel, Miller cycle, turbines...?

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Re: Alternative ways to power vehicles.

Postby Azrael » Fri Feb 13, 2009 8:50 pm UTC

Well, the Wankel engines are actually less efficient per hp than traditional engines, so there's no help to be found in that alternate.

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Re: Alternative ways to power vehicles.

Postby Sockmonkey » Fri Feb 13, 2009 9:27 pm UTC

vslayer wrote:i cant seem to find the article, but there was a guy a while back who developed an engine which recouperated its own heat to produce additional power, negating energy loss through both heat production and the cooling systems required in standard engines.


If you're thinking of the same article I am it was in Popular Mechanics or Popular Science and used coolant and exhaust heat to run a small steam turbine.

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Re: Alternative ways to power vehicles.

Postby Plasma Man » Mon Feb 16, 2009 5:01 pm UTC

Or there's this project, generating steam with a stationary generator, pumping it into an insulated, high-pressure tank in a car and using the stored steam to drive a steam engine and power the car.
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Re: Alternative ways to power vehicles.

Postby cleverdan » Tue Feb 17, 2009 7:46 am UTC

I did hear of one method that I thought was interesting, that came about in the 1970s during that oil crisis when oil prices were really high. It was on a documentary of ABC2 a while back. Instead of a regular combustion engine, in which the fuel is burnt in the pistons, the fuel is burnt in a kettle furnace, heating water to become steam and turning the engine that way. It at one stage generated a lot of interest from Detroit's Big 3, but as the oil prices dropped the interest in it fizzled out.

It was, at the time, touted as a significantly more efficient way to run an engine. It also isn't particular, it'd run diesel, petrol (gasoline in america) or even ethanol if it had a high enough volatility. It seems feasible enough, they showed a fleet of cars modified to run on the engine.

And I just read the previous post. So yeah.

You're off the hook because your comment managed to stay on topic. But coming out and saying you haven't read the (comparatively brief) thread is a great way to get posts deleted in SB.

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Re: Alternative ways to power vehicles.

Postby Hawknc » Tue Feb 17, 2009 10:46 am UTC

Wow, they developed...the locomotive? It's incredible! :P

Storing steam has the same problems as storing air, which is that it's not hugely efficient to store it high pressures. It would be more efficient to utilise the energy used to store it for driving the car directly, but the psychological drawcard of zero harmful tailpipe emissions is a strong one (and seemingly few people stop to think about the total lifecycle emissions). For all of steampunk's awesomeness, there's a reason you don't see too many steam-powered vehicles anymore.

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Re: Alternative ways to power vehicles.

Postby mosc » Tue Feb 17, 2009 5:20 pm UTC

Well, there are some laughable ideas here. Windmill on a car? Look, anything you add has to provide more energy than it costs.

Hybrids and regenerative breaking are well and good but really, the biggest helps are fundamental:
Decrease Weight
Decrease Drag

As far as alternative fuels, electric is a great option but is limited by crappy battery technology. How come nobody has brought up hydrogen. It's a lot more feasible than steam ffs. Hydrogen is cheap to make now and is in abundance. It also packs a lot of punch!
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Re: Alternative ways to power vehicles.

Postby Azrael » Tue Feb 17, 2009 5:33 pm UTC

mosc wrote:How come nobody has brought up hydrogen. It's a lot more feasible than steam ffs. Hydrogen is cheap to make now and is in abundance. It also packs a lot of punch!

And, much like steam or CNG, has that pesky problem of being stored safely.

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Re: Alternative ways to power vehicles.

Postby Bobthemonkey » Tue Feb 17, 2009 10:53 pm UTC

How about powering the vehicle with wind? It has been done in the Netherlands, though it only can go about 15 MPH.
The idea of being able to go straight upwind is a certain advantage.

As this is my first post I can't post a link, but you can Google Ventomobile or InVentus.

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Re: Alternative ways to power vehicles.

Postby Sockmonkey » Wed Feb 18, 2009 4:27 am UTC

There was a nifty article on the howstuffworks site about a car that runs on compressed air that burns fuel in the cylinders for the acceleration boost and runs on only air the rest of the time. I'll see if I can dig up the link if anyone is interested.

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Re: Alternative ways to power vehicles.

Postby Soralin » Wed Feb 18, 2009 5:03 am UTC

Azrael wrote:
mosc wrote:How come nobody has brought up hydrogen. It's a lot more feasible than steam ffs. Hydrogen is cheap to make now and is in abundance. It also packs a lot of punch!

And, much like steam or CNG, has that pesky problem of being stored safely.

If we attach the hydrogen to a chain of carbon atoms, then we could store it in a dense energy-rich easy to store liquid form. :)

But seriously, it's a good high energy density fuel that's easy to store and use. The only real problem with it right now is that you have to pull it up out of the ground, which means that there's a limited supply, and that there's more carbon, as CO2, in the air that used to be stored away underground. If you can get a good way of making the stuff without pulling more carbon out of the ground, then that solves both problems. (As long as you have something other then more fossil fuels to power the process of course)

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Re: Alternative ways to power vehicles.

Postby phonon266737 » Wed Feb 18, 2009 9:00 am UTC

(kind of a different point of view)
You don't have to stop using hydrocarbons. You just have to reduce the rate - CO2 doesn't go up a LOT every year, but over 30 years, it goes up a few ppm. Plus, it's well know (even "Co2 science" agrees http://www.co2science.org/articles/V3/N16/B2.php ) that high levels of CO2 increase growth rates of most (95%) plants (c3 plants, they are calledhttp://en.wikipedia.org/wiki/C3_carbon_fixation)
So, there's not a big rush to get things down to 150 ppm, especially when faced with 7 billion people all wanting dinner.

So here's a practical solution: get rid of the easiest carbon burners you can get rid of. Build more nuclear power, and use the waste heat for desalination (or use it to heat the city around it!) instead of sending water vapor into the sky.
Stop burning natural gas at power plants to make heat to boil water to make steam to spin a turbine to make electricity to go through wires to run my heat pump. Just pipe the gas to me and I'll burn it at home, with 98% efficiency because I can use the waste heat from combustion (and all the rest of the energy it makes) to heat my house.
But don't make me drive an expensive vehicle made from exotic materials that runs on highly purified hydrogen. I might get into an accident and have to send it to the junkyard. Just let me burn a few hundred gallons a year and pay $4 gallon for it. I can keep the same car I have now. the fuel costs aren't even as expensive as accident insurance (at $4!!!)

Save the high tech stuff for the heavy fuel consumers: power plants, big trucks, airplanes, etc.

When expanding the discussion much further beyond powering cars, it wouldn't be a bad idea to head over to Let's Talk About Energy Production.

-Az

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Re: Alternative ways to power vehicles.

Postby Comic JK » Fri Feb 20, 2009 4:01 am UTC

mosc wrote:As far as alternative fuels, electric is a great option but is limited by crappy battery technology. How come nobody has brought up hydrogen. It's a lot more feasible than steam ffs. Hydrogen is cheap to make now and is in abundance. It also packs a lot of punch!


This is a brief summary of what the gasoline-powered auto industry would like us to be saying.

Hydrogen is not particularly cheap to make; the current industry standard method, steam reformation of natural gas, wastes a great deal of energy and releases carbon dioxide to boot. Why don't they just electrolyze water? Because that takes even more energy. When you store electricity in a battery, you get back 80-90% of what you put in. When you use it to electrolyze water (losing half the energy) and then use the resulting hydrogen to make electricity again later (losing half the energy that remains), you are getting ripped off. This technology will probably never be practical; it is useful, however, in distracting people from the dismal efficiency of the internal combustion engine (~25%). Car companies like to tout their "hydrogen car of the future" precisely because it remains safely in the future--never in the present.

As to crappy battery technology--getting 120 miles of travel out of a battery, at the energy cost equivalent of $1/gallon of gasoline, is routine with today's technology. If 120 miles isn't enough for you--ie, if you can't rent a car on the off chance you want to go on a road trip--then you can quick-charge in half an hour or so, or start a battery exchange program to get on the road even faster. If we have to extend generator capacity to power more electric cars, then that's what we should do. Even the CO2 from coal-fired power plants is less, per mile driven, than that from all those gasoline engines; and power plants are much easier to switch to renewables than are private cars.

The trouble is the up-front cost--but if we can sell hybrids, which have the costs of gas and electric combined it one car, then surely we can sell simpler all-electric models.

So take the money out of hydrogen car programs, cut those billion-dollar ethanol subsidies to zero, and put the savings into full-electric cars. As a wise man once told me, "The Future's Electric!"
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Re: Alternative ways to power vehicles.

Postby Plasma Man » Fri Feb 20, 2009 5:01 pm UTC

Hawknc wrote:Wow, they developed...the locomotive? It's incredible! :P

Storing steam has the same problems as storing air, which is that it's not hugely efficient to store it high pressures. It would be more efficient to utilise the energy used to store it for driving the car directly, but the psychological drawcard of zero harmful tailpipe emissions is a strong one (and seemingly few people stop to think about the total lifecycle emissions). For all of steampunk's awesomeness, there's a reason you don't see too many steam-powered vehicles anymore.

Good point. Obviously steam / air power does have the advantage that the "fuel" can be produced using renewable energy to give zero overall emissions, but I can see the problems with storing and using it efficiently on vehicles.
It did give me an idea, though. Is there anything wrong, in principle, with the idea of steam-powered vehicles being powered by burning biomass? I'm aware that there would be practical problems with producing enough biomass, but it seems like there could be some potential applications for it. I'd think a good market for them would be farm vehicles, using them somewhere that can produce its own biomass.
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Re: Alternative ways to power vehicles.

Postby Hawknc » Fri Feb 20, 2009 8:17 pm UTC

Comic JK wrote:This is a brief summary of what the gasoline-powered auto industry would like us to be saying.

This is a pretty incorrect generalisation. Most automakers have been hedging their bets and trialling most alternatives - electricity, hydrogen, ethanol, biodiesel, natural gas, etc. Over the last 12 months, though, most of the major manufacturers have quietly pushed hydrogen to the side in favour of electric cars - the technology is much more readily available, and in an uncertain eceonomic climate, hydrogen cars are too expensive a gamble.

Comic JK wrote:Hydrogen is not particularly cheap to make; the current industry standard method, steam reformation of natural gas, wastes a great deal of energy and releases carbon dioxide to boot. Why don't they just electrolyze water? Because that takes even more energy. When you store electricity in a battery, you get back 80-90% of what you put in. When you use it to electrolyze water (losing half the energy) and then use the resulting hydrogen to make electricity again later (losing half the energy that remains), you are getting ripped off. This technology will probably never be practical; it is useful, however, in distracting people from the dismal efficiency of the internal combustion engine (~25%). Car companies like to tout their "hydrogen car of the future" precisely because it remains safely in the future--never in the present.

As to crappy battery technology--getting 120 miles of travel out of a battery, at the energy cost equivalent of $1/gallon of gasoline, is routine with today's technology. If 120 miles isn't enough for you--ie, if you can't rent a car on the off chance you want to go on a road trip--then you can quick-charge in half an hour or so, or start a battery exchange program to get on the road even faster. If we have to extend generator capacity to power more electric cars, then that's what we should do. Even the CO2 from coal-fired power plants is less, per mile driven, than that from all those gasoline engines; and power plants are much easier to switch to renewables than are private cars.

The trouble is the up-front cost--but if we can sell hybrids, which have the costs of gas and electric combined it one car, then surely we can sell simpler all-electric models.

So take the money out of hydrogen car programs, cut those billion-dollar ethanol subsidies to zero, and put the savings into full-electric cars. As a wise man once told me, "The Future's Electric!"

This, on the other hand, was pretty much what I was going to say. :P One note that I would like to make is that CO2 from electricity production depends very heavily on the generation mix. In the US, on average, electric cars will emit less than an equivalent petrol vehicle, but the same doesn't hold true for Australia, where electric cars will actually generate more CO2 emissions than petrol vehicles.

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Re: Alternative ways to power vehicles.

Postby mosc » Fri Feb 20, 2009 9:43 pm UTC

Comic JK wrote:
Hawknc wrote:So take the money out of hydrogen car programs, cut those billion-dollar ethanol subsidies to zero, and put the savings into full-electric cars. As a wise man once told me, "The Future's Electric!"

This, on the other hand, was pretty much what I was going to say. :P One note that I would like to make is that CO2 from electricity production depends very heavily on the generation mix. In the US, on average, electric cars will emit less than an equivalent petrol vehicle, but the same doesn't hold true for Australia, where electric cars will actually generate more CO2 emissions than petrol vehicles.

This is not just about emissions either. Battery acid is toxic waste. It's extremely corrosive and long lasting as well which means storage is an ongoing royal pain in the ass. They also contain lead and other toxic junk that makes disposal an expensive predicament. Global warming isn't the only environmental threat we face. You don't want to pollute your drinking water just to reduce CO2 emissions ffs.
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Re: Alternative ways to power vehicles.

Postby Comic JK » Fri Feb 20, 2009 10:10 pm UTC

mosc wrote:This is not just about emissions either. Battery acid is toxic waste. It's extremely corrosive and long lasting as well which means storage is an ongoing royal pain in the ass. They also contain lead and other toxic junk that makes disposal an expensive predicament. Global warming isn't the only environmental threat we face. You don't want to pollute your drinking water just to reduce CO2 emissions ffs.


You need to be more specific about which battery chemistry you're referring to. "Battery acid" is a feature of lead-acid batteries; electric cars use either nickel-cadnium or lithium-ion.
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Re: Alternative ways to power vehicles.

Postby netcrusher88 » Sat Feb 21, 2009 3:33 am UTC

Comic JK wrote:You need to be more specific about which battery chemistry you're referring to. "Battery acid" is a feature of lead-acid batteries; electric cars use either nickel-cadnium or lithium-ion.


NiCd and Lithium-ion batteries are also toxic, but not as outright destructive as lead-acid, and the toxicity of Lithium-ion is relatively quite low (small cells can be disposed of in the garbage). Lead-acid has a big advantage right now in terms of longevity (particularly deep-cycle versions), capacity, and cost, but Li-ion is catching up because of a few breakthroughs in the last few years even though the resulting improvements are still expensive. NiCd, although cheaper than Li-ion, is a bad idea because of the so-called memory effect, where the battery will lose capacity if you don't fully discharge and recharge it every time - the "memory" can be sort of massaged out of it through a time consuming full discharge-recharge cycle (time-consuming because you have to completely drain the battery, not just down to where it isn't useful anymore) or two, but that's an imperfect solution and it will never be like new.

There are recycling (or disposal) options for all battery types. They are severely underused, although people are starting to get used to the idea of recycling cell phone and laptop batteries. It'll be a while before everyone thinks of discarded batteries as hazardous waste though.
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Re: Alternative ways to power vehicles.

Postby Minerva » Sat Feb 21, 2009 11:44 am UTC

Cadmium is a pretty toxic metal, it's just as bad as lead. NiCd is certainly no better than lead-acid on environmental grounds.
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Re: Alternative ways to power vehicles.

Postby Hawknc » Sat Feb 21, 2009 1:30 pm UTC

Thankfully nobody uses NiCd anymore (well, not in vehicles anyway). NiMH (nickel metal hydride) is a higher-performing alternative that's found in the Prius and other hybrids that have been released anytime in the last five years or more, isn't as toxic, and doesn't suffer from the same memory effect issues. The only place I've seen Nicds in the last few years are cheap low-mAh rechargeable batteries, to be honest.

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Re: Alternative ways to power vehicles.

Postby Comic JK » Sat Feb 21, 2009 8:57 pm UTC

Hawknc wrote:Thankfully nobody uses NiCd anymore (well, not in vehicles anyway). NiMH (nickel metal hydride) is a higher-performing alternative that's found in the Prius and other hybrids that have been released anytime in the last five years or more, isn't as toxic, and doesn't suffer from the same memory effect issues. The only place I've seen Nicds in the last few years are cheap low-mAh rechargeable batteries, to be honest.


You're right; I should have said nickel metal hydride, not nickel cadnium. That's also, I believe, the battery technology that will be used in the Volt (if GM survives). This plug-in hybrid should be a huge step forward in terms of public image of electric cars. The future, though, seems to be lithium ion, because of their high capacity and light weight, and as someone noted, even if we don't recycle these batteries, their waste does not pose much of a challenge. The biggest technical problem now is getting lithium-ion batteries to quick-charge without bursting into flames. If we can build batteries that charge in ten minutes or less, as fast as gassing up a car, then limited range becomes pretty insignificant, and GM can drop the gas engine from the Volt and sell it for less.
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