Re: [Phys-l] [ncnaapt] another crackpot idea from theCalifornia legislative assembly

[curtis osterhoudt <flutzpah@yahoo.com>]

Yes, yes, and probably not. But that simply means that getting energy out of 
them is difficult. They'd be much better to put flexy piezos on car tires and 
rely on the fact that once per revolution your tires deform quite a lot. 


 The Italian researchers got 1/18 gallon of gas of energy out of 10 meters of 
road. Was that over a week? A year? During one rush-hour?

Sure, you can put down hundreds of km worth of piezos on various highways. You 
still have to capture the energy, shuttle it to a useful collection station 
(copper isn't THAT cheap now), condition it (which very likely means storing 
it), and then do something with it. Suppose they got 2000 W-hr over the course 
of a day (big assumption on my part). Scaling it to hundreds of km of roads 
gives perhaps 70 GJ, which is about how much a SINGLE typical automobile used 
per year in the year 2000. That's assuming 100% efficiency at every step, the 
ability to feed it all into the energy grid, and whatever other generous 
assumptions I've made. 


If, on the other hand, they captured that 2000 W-h over the course of a month or 
a year, then you've just recovered one vehicle's worth of energy expenditure. 
I'm not so sure the infrastructure is at ALL supportive of the hare-brainedness 
of this scheme. They could run a single gasoline generator, get cleaner, more 
reliable, and better-conditioned electricity at a *tiny* fraction of the cost. 


 /**************************************
"The four points of the compass be logic, knowledge, wisdom and the unknown. 
Some do bow in that final direction. Others advance upon it. To bow before the 
one is to lose sight of the three. I may submit to the unknown, but never to the 
unknowable." ~~Roger Zelazny, in "Lord of Light"
***************************************/




________________________________
From: William Robertson <wrobert9@ix.netcom.com>
To: Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu>
Sent: Mon, February 28, 2011 5:10:09 PM
Subject: Re: [Phys-l] [ncnaapt] another crackpot idea from theCalifornia 
legislative assembly

Maybe this is a stupid question, but ........  Don't piezoelectric  
crystals work with about a tenth of a percent deformation? And  
wouldn't that small deformation be insignificant in terms of the  
normal variations in a road surface? And thus would there really be  
any effect on gas mileage?

Bill


On Feb 28, 2011, at 4:49 PM, curtis osterhoudt wrote:

> That's an interesting article. So the Italians were able to generate  
> "2000
> Watt-hours" of energy from 10 m of highway. Of course, the article  
> doesn't say
> over what time period, or what the traffic volume was.
>
>
>   This is roughly equivalent to the amount of energy released by  
> combusting
> 1/18 gallon of gasoline.
>
>
> /**************************************
> "The four points of the compass be logic, knowledge, wisdom and the  
> unknown.
> Some do bow in that final direction. Others advance upon it. To bow  
> before the
> one is to lose sight of the three. I may submit to the unknown, but  
> never to the
> unknowable." ~~Roger Zelazny, in "Lord of Light"
> ***************************************/

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