From: carl@SOL1.GPS.CALTECH.EDU (Carl J Lydick)
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
Subject: Re: Flywheel batteries as EV power source
Date: 20 Dec 1992 22:52:01 GMT
Organization: HST Wide Field/Planetary Camera
Distribution: world
Reply-To: carl@SOL1.GPS.CALTECH.EDU
NNTP-Posting-Host: sol1.gps.caltech.edu

In article <BzF5L0.LzK@cs.uiuc.edu>, morrison@cs.uiuc.edu (Vance Morrison) writes:
>>I'm afraid you've forgotten the law of conservation of energy again.  I ask
>>again:  IF THE ENERGY THAT'S BEING DUMPED DOESN'T END UP AS HEAT, WHERE'S IT
>>GOING?  HOW'S IT BEING TRANSFERRED OUT OF THE SYSTEM?
>
>You are making two assumptions that may not be justified.  First you assume
>that all energy gets dumped as heat.   It is quite possible that this 
>energy can be dumped into some sort of chemical energy, (heat of fusion,
>vaporization or endothermic reaction).  Granted, I have not given a 
>possible scenerio, I merely point out that conservation of energy is NOT
>a proof of infeasibility.  

If you return to my original post in this thread, I pointed out that the
requirement was that you encase the flywheel in something massive enough that
all the energy of the flywheel is insufficient to vaporize the container.

>Second, heat by itself is not THAT bad.  I really don't care if the flywheel
>compartment is hot enough to melt steel as long as I survive the crash 
>unburned.

Fine.  You're now agreeing with me that you need to put the flywheel in a
massive enough container to prevent vaporization of the containment (and the
resulting explosion).

>If the crash was bad enough that I don't survive,

What about failure of the flywheel in other than a crash?

>does it matter
>that much if I get burned too?

As I pointed out above, if you don't put enough massive shielding around the
flywheel, you're going to get an explosion, not just heat.

>The problem with heat is that it can cause
>explosions if released too quickly.

That's right.  And the flywheel's going to release as much energy as would a
couple of gallons of gasoline.  But the flywheel's going to release it in the
space of a second.

>Preventing explosions IS a goal
>that good engineering has a chance of accomplishing.  Again, I don't offer
>solutions, just pointing out that it is not as hopeless as you make it 
>out to be.

I never said it was hopeless.  Certainly you can build massive enough shielding
to prevent the explosion.  The question is, how much weight are we talking
about here?

>On the other hand, I could see how solving these problems might be expensive
>and that a better overall solution could be found to the EV problem by
>not using flywheels as the primary storage device.  

That's the point I've been making all along:  You need massive shielding, which
increases the load, which means you've got to store more energy, which means
you need even more massive shielding....
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: CARL@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL

Disclaimer:  Hey, I understand VAXen and VMS.  That's what I get paid for.  My
understanding of astronomy is purely at the amateur level (or below).  So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it.  If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.
Newsgroups: sci.electronics