Energy

[holycanoli]

Hello.

We purchased a hand-crank flash light the other day. It got me to thinking, when you crank the handle, you are in a very real sense moving something up and down. It powers the light in this case. However, what if this was done on a grander scale?

Someone brought up the idea on NPR one day of turning a jogging track into a self-sustaining enterprise.

What you do is replace the track with a mat that has thousands of these levers imbedded in it. On the outside, it looks like a standard track but beneath the surface are thousands of these lever mechanisms. The imbedded levers are "pushed" each time a jogger's foot lands on them (they are about the size of a matchbox) and it captures that energy and feeds it to a battery which stores the energy. When it gets dark, the energy powers the lights that illuminate the track.

The bigger idea, of course, are the highways and using the automobiles to trigger devices such as these to power the highway lights.

Has anybody ever considered the possibilities of doing something like this?

[madurobob]

Actually, making exercise machines generate electrity (http://www.engadget.com/2005/06/11/tacx-fortius-training-bike-generate-your-own-electricity/) is not a new concept. No "levers" and such, just standard rotational force (turning magnets inside a coil of wires - like any generator).

Wouldn't quite work on I-40, though.

[RecoveringYuppy]

The bigger idea, of course, are the highways and using the automobiles to trigger devices such as these to power the highway lights.

If the case of having the joggers power their lighting you've got a reasonable idea because the energy is otherwise being wasted. But the energy of the cars is not being wasted, it's being used to move the cars. If the highway is somehow extracting power from the cars it's going to show up as a reduction in gas mileage.

[Rob Lister]

well, how much power (in watts) do you think this method of generation would produce?

[balrog666]

well, how much power (in watts) do you think this method of generation would produce?

Trained athletes can generate about 200 watts (intermittently for as long as an hour). People walking the local mall can generate enough to light an LED or two.

[DRBUZZ0]

This has been proposed before. The amount of energy is generally not worth the amount of effort and equipment needed to harvest it.

Although, I had heard a while ago about a scheme to generate electricity from bikes and tred mills and such at a fitness club. Obviously this was in California, because Californians eat that stuff up. Obviously it was also a gimic. But it might make some of the soccer various valley soccer-moms feel like they made a difference for the environment.... then afterward they can drive their hummer over to the anti-vaccine rally . But that's California for you...

[fuelair]

You always get less out than you put in. Accept this and all will be well!!!

[Gord_in_Toronto]

There used to be a department store in Toronto that powered their escalator by the people coming through the revolving doors. I know this is true because when I drove by at night the doors were locked and the escaltors were not moving. :D

[rjh01]

One major problem is that storing electricity is very expensive.

[holycanoli]

If the case of having the joggers power their lighting you've got a reasonable idea because the energy is otherwise being wasted. But the energy of the cars is not being wasted, it's being used to move the cars. If the highway is somehow extracting power from the cars it's going to show up as a reduction in gas mileage.

Well, it's not my idea...I heard it on an NPR station (which also broadcasts APM broadcasts).

I didn't explain it properly. The car's movement will trigger switches in the pavement in the same way that the hand-crank on my flashlight charged a battery. It would require some micro-engineering and some materials that can stand up to the constant pounding (albeit extrememly acute pounding) of 3 and 5 thousand pound vehicle.

My question, I guess, is why not? Pave a new construction project with some of these switches and see what you get out of it. If nothing, just pour concrete over the whole expirment.

[holycanoli]

well, how much power (in watts) do you think this method of generation would produce?

I really do not know. I'm a chubby kid from Cloverleaf, Texas.

It hinges on the storage capacity of the batteries more than anything elese I presume. But I think we can make some assumptions that are self evident:


Cars aren't going anywhere
Our fossil fuels are going to run out some day
There is a bunch of kinetic energy being squandered.


This is just an idea I wanted to release into the forum. Maybe one of your brighter lights can make something of it.

[holycanoli]

This has been proposed before. The amount of energy is generally not worth the amount of effort and equipment needed to harvest it.

Although, I had heard a while ago about a scheme to generate electricity from bikes and tred mills and such at a fitness club. Obviously this was in California, because Californians eat that stuff up. Obviously it was also a gimic. But it might make some of the soccer various valley soccer-moms feel like they made a difference for the environment.... then afterward they can drive their hummer over to the anti-vaccine rally . But that's California for you...

he he he

[RecoveringYuppy]

My question, I guess, is why not? Pave a new construction project with some of these switches and see what you get out of it. If nothing, just pour concrete over the whole expirment.
We don't need to guess anymore. This aspect of energy has been understood for two centuries now.

[Hindmost]

there is still no such thing as a free lunch...people will have to eat more to generate the power.

glenn

[69dodge]

I didn't explain it properly. The car's movement will trigger switches in the pavement in the same way that the hand-crank on my flashlight charged a battery.


No, you explained it fine.

But, as RecoveringYuppy said, a car will burn more gasonline if it's powering streetlights and propelling itself than if it's just propelling itself.

[The Man]

I do find the thought of all my neighbors exercising so I can play my X-box quite appealing though.

[The_Animus]

I am probably not understanding this on some level. If you did the idea proposed in the OP why would cars get worse milage? Right now cars drive down the street. The weight of the car pressed down on the road, and the wheels move over the road when driving. The same exact thing would be happening with this idea, the only difference is that the weight of the vehicle will be pressing upon tiny switches under the road. I'm sure you are right that it must result in worse gas milage based on the law of conservation of energy. I just don't understand how.

[RecoveringYuppy]

The road surface won't be exactly the same in the two cases. In the case with the mechanism under the surface the surface will be moving up and down to some degree. That will appear to the car as a higher friction surface. As the car depresses the "switch" it depresses the road surface. The car would be constantly driving out of one of these depressions.

Another practical concern is that the lights are stationary. Since they don't move they can use heavy batteries to store power usually provided by solar energy. A car can't afford the weight of the batteries as easily. The cars portable energy supply (gasoline) isn't worth squandering.

[DRBUZZ0]

Yes, the energy would have to come from the deformation of the road. The deformation of a car on something like concrete is very small, almost nothing.. you would need much more to get any energy and that would impact gas mileage. You loose in the end.

The only place I can think that there might be energy to recover that would otherwise be lost would be possibly bridges with dampers. As cars pass over the bridge vibrates. You can't really avoid that from happening but to absorbe the energy there are sometimes hydrolic dampers. The energy isn't very much but it would end up compressing fluid and just get converted to heat.

Maybe if you could use a peizoelectric substance or something you could get a tiny amount of electricity. It wouldn't be that effecient though. I doubt it would ever be worth it.

[rjh01]

The idea would work where it is known that cars have to slow down, like at traffic lights and corners. Put them in the road and when the lights go red any car that approaches, instead of braking the road does the braking for them. All the driver needs to do is take their foot off the gas peddle.

[The_Animus]

What if you only put the switches on downward hills and slopes? Obviously it would only be on the half of the road that the car goes downward.

Many times people don't need to push the gas at all when going downhill due to the extra momentum. Sometimes you even have to slow down so you don't go over the speed limit. Would this solve the issue of losing gas mileage?

[The Man]

The idea would work where it is known that cars have to slow down, like at traffic lights and corners. Put them in the road and when the lights go red any car that approaches, instead of braking the road does the braking for them. All the driver needs to do is take their foot off the gas peddle.

In hybrid cars, when you apply the brake, the electric drive motors become like generators. The reverse EMF force helps slow the vehicle and the generated electricity is used by the vehicle. The company I work for uses such systems on some of our equipment. So I should know what they are called but can not remember and could not find a specific reference. The term “Recursive Brake” comes to mind but I’m not sure, when I return to work I’ll look it up. The point is that even this direct energy from braking recovery system is not even sufficient to replace the energy used getting up to speed or up a hill, let alone provide a surplus.

[RecoveringYuppy]

Many times people don't need to push the gas at all when going downhill due to the extra momentum. Sometimes you even have to slow down so you don't go over the speed limit. Would this solve the issue of losing gas mileage?
Yes, but it would interfere with the regenerative braking that rjh01 just mentioned and which is being used in more and more cars.

[The Man]

Yes, but it would interfere with the regenerative braking that rjh01 just mentioned and which is being used in more and more cars.

"Regenerative braking" that's it, thanks RecoveringYuppy. Don't ask my why I could not remember that. I hope nobody I work with is on this thread, I might have "some splainen to do".

[holycanoli]

No, you explained it fine.

But, as RecoveringYuppy said, a car will burn more gasonline if it's powering streetlights and propelling itself than if it's just propelling itself.

Na, the switches will be very, very small. Sort of like running over a miniature ramp--about 0.25 inches up from the ground. There will be thousands of these switches in the concrete made of hardened metal. A tire hits probably three or four of these switches with each 4-5 inch segment of it's arc as it runs over the ground.

The word "ramp" gives off the wrong impression of a miniature Prudential rock. I used it to transmit the idea of a wheel running over it but it what I am envisioning is something smooth like a large ball bearing

As the car propels forward at normal speed, it depresses these switches into the ground. They switch turns a very small generator like in my hand-crank flashlight and instead of powering a light, it transfers that energy to a battery bank located next to the road. The traffic lights on the road draw part of their energy from the battery that is powered by the movement of vehicles.

I'm certainly not an engineer, electrician, or very smart for that matter. But it makes some sort of sense of having this "crank" idea implemented on a large scale I feel. Maybe not. The costs would certainly be high.

[egslim]

My question, I guess, is why not?
Conservation of energy.

Energy can never be created from nothing, it can only be converted. Those switches would convert kinetic or potential energy into electricity, which means the engine has to burn more fuel to maintain potential energy/height and kinetic energy/speed.

In addition, car engines are less fuel efficient than a dedicated power plant.

The only exception would be in places where people brake, like steep downhill or in front of a stopsign or red traffic light. Braking converts kinetic energy into heat, which is waste. On the other hand, it would probably be more practical to install brakes that convert kinetic energy into electricity.

I'm certainly not an engineer, electrician, or very smart for that matter. But it makes some sort of sense of having this "crank" idea implemented on a large scale I feel.
It's an ingenious idea, it just doesn't take the law of conservation of energy into account. And that's a very fundamental physics law. The laws of physics take precedence over ingenuity every time. :)

[holycanoli]

Conservation of energy.

Energy can never be created from nothing, it can only be converted. Those switches would convert kinetic or potential energy into electricity, which means the engine has to burn more fuel to maintain potential energy/height and kinetic energy/speed.

In addition, car engines are less fuel efficient than a dedicated power plant.

The only exception would be in places where people brake, like steep downhill or in front of a stopsign or red traffic light. Braking converts kinetic energy into heat, which is waste. On the other hand, it would probably be more practical to install brakes that convert kinetic energy into electricity.


It's an ingenious idea, it just doesn't take the law of conservation of energy into account. And that's a very fundamental physics law. The laws of physics take precedence over ingenuity every time. :)

Oh well.

[GreNME]

Oh well.

Don't give up so fast. There are people who are working on ways to make some alternate sources of energy. Dean Kamen, for example, envisions cars that use a modified stirling engine to be a distributed power plant (http://blogs.business2.com/greenwombat/2007/08/a-visit-to-dean.html) for cities. Frankly, I think his idea is great. He says he already has two small third-world towns running on stirling engines of his design (running "on freaking cow dung"), so his main challenge is three-fold the way I see it:

1. Get the stirling able to produce enough juice quick enough to keep an auto reasonably charged for a useful distance.
2. Develop a reliable way for users of such cars to plug them into homes and parking areas to produce back into the grid once the car is fully charged.
3. Convince cities that it is worthwhile to make such drastic accomodating changes to their infrastructures to allow for such a technology.

One thing Kamen has also talked about regarding energy storage is having older EV auto batteries be distributed to power companies for storage of energy, since even though the batteries may be too low in efficiency for the cars they are taken from they still hold some charge. This lengthens the useful life of the batteries themselves and gives a place to put the batteries that are taken out of automotive use. The problem of disposal after any useful life in them is gone is still an issue, though, but there could be a market for breaking these batteries down for remanufacture to repopulate the battery market.

That's just one idea, and one I think is highly doable, but there are still problems with it. The main problem I see right now is that there isn't enough perceived need for so drastic a change in the auto market, as well as the upheaval that would be caused by a whole new transition in the mechanics of how our cars work. This wouldn't just affect manufacturing, it would also affect sales and maintenance for vehicles, so the economic implications need to be kept in mind. The thing is, though, that there are people working on things to do when the need is perceived as great enough by the larger population, but for right now there just isn't enough perception by the general public that such changes are necessary just yet. That's going to be the greatest hurdle to jump.

[Pope130]

You could put the generator levers on the suspension in place of the shock absorbers. That would recover energy currently being thrown away as heat, and provide some use for all those pot-holes the road department has provided us.

Robert

[The Man]

You could put the generator levers on the suspension in place of the shock absorbers. That would recover energy currently being thrown away as heat, and provide some use for all those pot-holes the road department has provided us.

Robert


That's all my town needs.
An excuse, not to fix pot-holes.

[Soapy Sam]

Potholes are the cheapest way to slow down speeders.

[ZirconBlue]

Potholes are the cheapest way to slow down speeders.


Hmmm. How about using these "energy converters" along with/instead of speed bumps?

[The Man]

Hmmm. How about using these "energy converters" along with/instead of speed bumps?

Well, I like this one better, at least then I would have an excuse for when I fly over speed bumps in my car or use them to get “air” on my motorcycle.

“But Officer I was just trying to help prevent a power outage.”


Disclaimer: The statements made above are for purposes of humor only. The author makes no admission as to having engaged or intending to engage in such, clearly dangerous and illegal, activities. The author further stipulates that no other persons should act or intend to act as described above.

[Tailgater]

Energy not used that has no affect on car/truck performance is the wind force pushed out. If you have ever been walking down the side of an interstate, wind gusts from passing trucks can almost knock you over.

[RecoveringYuppy]

Energy not used that has no affect on car/truck performance is the wind force pushed out. If you have ever been walking down the side of an interstate, wind gusts from passing trucks can almost knock you over.
Uhh, not so fast. Have you ever heard of "drafting"? If you try to extract energy from that wind stream there's a very real chance you'll increase friction against the truck.

[Tailgater]

Uhh, not so fast. Have you ever heard of "drafting"? If you try to extract energy from that wind stream there's a very real chance you'll increase friction against the truck.

Barriers already exist in the form of sound barrier walls and various guard rails. I don't see how drafting would change.