Re: battery pulsing gizmo
- From: John Johnson <null@xxxxxxxxxxx>
- Date: Tue, 10 Apr 2007 04:36:59 GMT
In article <h5DSh.18255$hO2.673@edtnps82>,
"Pete M" <chuck_wagon@xxxxxxxxx> wrote:
"John Johnson" <null@xxxxxxxxxxx> wrote in message
news:null-947C13.21144609042007@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <lkh1t61h.fsf@xxxxxxxxxx>,
Gene Cash <gcash@xxxxxxxxxxxxxxxxxxxxxxx> wrote:
John Johnson <null@xxxxxxxxxxx> writes:
If it's the sort of device that I'm thinking of (a radio-isotope
thermal
generator, RTG), they still see modest use in spacecraft (unmanned).
They are a reliable source of power for probes that will travel far
from
the sun, where solar panels wouldn't provide sufficient energy.
Exactly, except small, with a hot middle and cold outside for the
thermocouples.
I don't really know much about the boundaries of the technology (e.g.
size limits, power output, output versus size, etc.) but I'm sure some
research online would turn up at least the basic parameters,
controversies, etc.
Probably not, considering this stuff was in my '70 World Book
encyclopaedia Year Book and I haven't heard anything about it since.
I meant RTG's in general, sorry.
It's essentially a AA battery that lasts 8 months demonstrated, with the
possiblity of many years with more research.
Yeah, piling up a bunch of ceramic radio-isotopes with thermocouples
buried in them doesn't seem like a really good thing, unless you've got
a way of dealing with the waste stream (and burial isn't a particularly
good option). Provided that the waste _could_ be dealt with, then the
concept has its interest, anyway.
Still, fuel cells are rather less politically-charged, potentially
(depending on the particular technology used) less problematic in case
of accidental destruction, and potentially a better use of resources (if
you can source fuel locally, if the cell body and mechanism are durable,
etc.).
I just read about a sugar-solution fuel cell technology that's being
developed. Efficiency is low (surprise), and applications are in that
"five to seven" year (which really means something like "a long time or
maybe never") horizon. Still, the methanol solution cells are quite
promising already, so maybe we'll see some consumer fuel-cell stuff
hitting the market soon.
--
Later,
John
johajohn@xxxxxxxxxxxxxxxxxxx
'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.
Was that a typo... Methanol ? :o) The buzz these days seems to be about
ethanol.
No, there's quite a bit of research into methanol fuel cells too. I'm
not entirely sure of the significance of the different fuels (perhaps
different chemistry allowing different catalysts?), but there's ones
fueled by ethanol, methanol, and sugar, with the alcohol ones varying by
concentration of the alcohol solution used (energy efficiency apparently
is better with lower percentage of alcohol, but obviously fuel volume
goes up, etc.)
Well, I've seen analyses that show ethanol being modestly
Ahh.. ethanol.
I read an article recently where they estimated the petroleum cost of
fertilizers, transport, distillation etc to make 10 gal of ethanol from corn
was I think about 8 gal.
Aside from that, you can eat corn or feed it to cattle or something.... why
would you swap 8 gal of petroleum for 10 gal of ethanol...and petroleum
probably has a significantly higher energy density. Seems the pain in the
ass factor alone would make it not worth the effort, aside from
wasting.....an awful lot of hard earned corn.
The bottom line seemed to be that if we could make ethanol from corn STALKs
instead of corn, we could be ahead.
energy-positive to slightly energy-negative, depending on who did the
study, what they were considering, etc. Since these studies counted
BTUs, the gallons to gallons conversion isn't something that I know
(except that 8 gal. of ethanol has _far_ less energy than 8 gal. of
gasoline, but not all the petroleum used is gas, etc.)
Another reason I've wondered why they insist on mixing ethanol instead of
methanol with gas is... I heard someplace you can make methanol (wood
alcohol) by heating wood in the absence of oxygen, like in a partial vacuum.
Corn stalks, sawdust, slash... all kinds of things come to mind.
Yeah, but it's pretty inefficient. There's probably better ways of using
the energy contained in that plant matter. Corn stalks are typically
left on the field under no-till techniques, which limits topsoil loss
and runoff (good things), so removing them from the field isn't
necessarily a purely good thing. Often the cobs and shucks are burned to
dry the grain (or sold as polishing/cleaning media; corncob is popular
with ammunition reloaders, IIRC).
There's no obvious, simple answers to energy. We're going to have to
make some serious decisions about energy usage, acceptable trade-offs,
and how future-proof we want to be, or we'll make them by default. In
the meantime, I'll ride my motorcycle while I can afford it. When I
can't, well I hope I can still ride a bicycle by then!
--
Later,
John
johajohn@xxxxxxxxxxxxxxxxxxx
'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.
.
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