NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/sci/electron/21563

Internet Message Format | 1992-12-25 | 4.0 KB

Xref: sparky sci.electronics:21563 sci.energy:6446 rec.autos:30519
Newsgroups: sci.electronics,sci.energy,rec.autos
Path: sparky!uunet!gatech!emory!wa4mei!ke4zv!gary
From: [e-mail] (Gary Coffman)
Subject: Re: Flywheel batteries as EV power source
Message-ID: <[e-mail]>
Reply-To: [e-mail] (Gary Coffman)
Organization: Destructive Testing Systems
References: <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]>
Date: Fri, 25 Dec 1992 13:30:31 GMT
Lines: 62

In article <[e-mail]> () writes:
>In article <[e-mail]>, [e-mail] (Richard Stead) writes:
>>
>> In article <[e-mail]>,  writes:
>> > In article <[e-mail]>, [e-mail] (Richard Stead) writes:
>And when Stead actually mananges to make a point...
>
>Wait there's one here somewhere...
>
>> the way the molecules work is that you
>> must do work against the molecules to separate them, but once separated,
>> they snap back, releasing the acculmulated strain energy as heat.  That's
>> right, energy is conserved, and a pile of shredded composite does not
>> represent more energy than the whole piece.  Entropy simply means that
>> energy has been converted to heat.
>
>Unfortunately wrong, and very sloppy.  Take a ream of paper and turn it into
>scraps and tell me you haven't expended energy.  That energy came from the
>flywheel hense the fluff does not have the same energy as the initial flywheel.
Sorry wrong. If you tear a ream of paper into shreds, the chemical potential
energy in your body has been converted to mechanical energy which degrades
to heat, both in your inefficient muscles and in the torn paper. Now the
paper doesn't get very hot, but that's because you don't have to expend
much energy tearing paper. Try taking a wire coathanger and bending it
back and forth until it breaks. Both you and it will get hot. With the
flywheel, there's an enormous amount of energy released in a very short
time. None of that energy can leave the system until the containment
ruptures. *All* of it degrades to heat, megajoules of heat, equivalent
to about 200 pounds of dynamite.

>Energy has been used bending molecules, which may or may not snap back, but
>more significantly in breaking bonds which originally held the flywheel
>together.  Now if you've got the inter fiber bond strength of a material of
>carbon carbon fibers we could use for a fly wheel, your a hell of a lot
>farther ahead that most in the carbon carbon field.  Now is this energy enough
>to make the fluff safe, I don't know, that's why I asked.  Remember that
>carbon carbon bonds are one of the strongest bonds around, thats why we
>want to use carbon carbon in the first place.
>
>> I repeat for the billionth time, energy is conserved!
>
>Can't you listen to your own point?

You are the one who doesn't understand. It's a closed system. All the
energy originally contained in the flywheel degrades to heat if kinetic
particles don't penetrate the housing and escape immediately. Breaking
a chemical bond takes energy, but that energy doesn't disappear when
the bond breaks. It reappears as kinetic rebound in the component atoms.
Another term for kinetic motion of atoms is *heat*. *All* the energy in
the flywheel degrades to heat, and it happens in microseconds. Releasing
8 MJ of energy in microseconds is called an explosion. A damn big one.

You'd do well to study thermodynamics and quantum chemistry before you
flame someone about something you don't understand.

Gary

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