🚀 go-pugleaf

In article <CvoH2I.AIJ@usenet.ucs.indiana.edu>,
artemis <amirza@bronze.ucs.indiana.edu> wrote:

>Chemical energy to electrical energy ~ 20-25%
>HV AC to LV DC via the Trace switching charger >90%
>LV DC to CE via the batteries ~ 85-90%
>CE to HV AC via the Trace >90%
>
>Biggest loss of energy is in the generator, if you can up it's
>efficiency a little bit you've gained a lot.

If you split the "generator" into the engine and the generator proper,
you'll find that essentially all the losses are in the engine.
Generators (and motors) easily exceed 95% efficiency, while a heat
engine has an inherent limit in the mid 30s, and will not approach it
very closely.

So essentially all your losses are in converting the high-grade heat
produced by burning the fuel into mechanical energy (with low-grade
heat as waste).  Once you have it in a good form, you can convert it
back and forth between good forms almost for free, and store it at a
loss comparable to California sales tax.  B-)

If you have to start from a fuel, you can get beyond the Carnot Cycle
heat-engine limit by using a fuel cell rather than burning it, but
fuel cells are still cantankerous beasts and not quite ready for
cabin power supply service.

Another approach is to use the low-grade waste heat for other things
such as heating your house or water.  The exhaust and coolant
temperatures of even a very efficient heat engine are still higher
than the target temperatures for house or water, and all the heat
is still there.  If you were going to burn propane to heat them
anyhow, you might as well pick off some otherwise wasted power.

Downsides are that a heat-exchanger failures can cause havoc and
your heating and electrical demands don't necessarily occur at
anything approximating the same time, so equipment quality can be
life-critical and process-control becomes a pain.  Trying to scavenge
waste heat is a game best left to large utility companies or
industrial plants, which have enough to pay for the effort of
going after it.  K.I.S.S. and you have fewer system failures at
inopportune times.

Big point, though, is that a typical instalation only uses the
generator to cover holes in some other primary supply that is
lower cost.  Cloudy days for solar, calm days for wind, power
outages for utility-fed, etc.  Given this usage pattern, the
generator's lower efficiency becomes insignificant.

The biggest point is that efficiency isn't the proper measure in the
first place.  The proper measure is cost {which includes efficiency
among the things it signals} and a generator beats non-rechargable
batteries hands-down.  (Even large electric utility companies use
them - typically in the form of a low-speed jet engines the size of
railroad cars.)

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Michael McClary						mcclary@netcom.com
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