Re: Methane and other winds (was Re: alternatives to big oil andifthey can ...

From: Michael M. Butler (
Date: Sat Feb 05 2000 - 10:36:58 MST

One of the big problems here is "is air free"? The most compact energy
density ratings will come from things that react with air (the rusting
nail, other combustion, etc.) If you don't weigh the air, and there's
always plenty of it, you are talking about something that puts
self-contained systems like batteries at a disadvantage. That might be
OK for your system, or it might not.

Stirling Westrup wrote:
> Spike Jones wrote:
> > > Stirling Westrup wrote: What
> > > is the highest density chemical energy storage that is currently known?
> >
> > This is a much more complicated question than it looks.
> Yeah. Actually I knew that.
> >
> > > answer different if we look at joules per mililiter instead of per gram?
> >
> > Of course. If volume doesnt matter, hydrogen and flourine
> > pack a tremendous bang per gram. Solid rocket fuels are
> > way down on specific impulse per unit weight, but they
> > exceed liquid rocket impulse as a function of volume. Furthermore
> > the answer depends on how you want to actually *use* the energy.
> > For instance, a hand grenade has less chemical energy than
> > a twinky. If you are interested in converting energy via
> > internal combustion, good old octane is quite respectable.
> > As far as energy released, a rusting piece of iron does well.
> > If you are imagining chemical storage for nanoconstruction,
> > mitochondria have found a good energy transfer medium,
> > the breakdown of simple sugars.
> >
> > Please sharpen the question Stirling.
> Okay, I am working on a chemical model for futuristic role-playing purposes.
> What I am trying to find out (in my naive way) is what is the maximum amount of
> energy you can get from a chemical reaction. Any reaction. It doesn't matter if
> it takes a billion years to react, or if the energy is produced by expanding
> gasses (such as gunpowder) or by heat from simple combustion (as in octane).
> The idea is to get an upper bound on the theoretically achievable, and to then
> attempt to express different classes of chemical reaction as percentages of the
> achievable. So, if the most energetic reaction produces some X j/g then we
> might say that the theoretical maximal gunpower produces kX j/g where k is a
> characteristic of that mode of chemical reaction. By the same token, we end up
> with factors k1, k2, k3 and so on for theoretical most caloric food, best
> rocket propelant, and electricity-producing reaction. I would then attempt to
> rate where we stood by doing some research in various newsgroups (including
> this one, naturally) to get candidates for our best current tech in each
> category. If I can get a coherent enough picture, I can build a tech-level
> model for chemical technology.
> --
> Stirling Westrup | Use of the Internet by this poster
> | is not to be construed as a tacit
> | endorsement of Western Technological
> | Civilization or its appurtenances.

This archive was generated by hypermail 2b29 : Thu Jul 27 2000 - 14:03:27 MDT