From: ronkean@juno.com
Date: Tue Aug 31 1999 - 01:01:36 MDT
On Mon, 30 Aug 1999 23:15:56 -0500 "Billy Brown"
<ewbrownv@mindspring.com> writes:
> Robert J. Bradbury wrote:
> > However, the calculation assumes that every person on the planet
> can> > find *some* use for his 10 kg allocation of robots consuming
> ~100KW> > of power. Right now most of the people on the planet don't
come
> > close to consuming 100KW. A standard house (with 200 Amp service,
> > probably above average), only pulls 20KW when it is maxed out.
A technicality: Houses in the US are normally fed with 240 volts single
phase center-tapped, on three wires. One wire is the neutral or ground,
and the other two wires each carry 120 volts relative to ground, with 240
volts between the two live wires. The 240 is used for running heat
pumps, air conditioners, and some clothes dryers and water heaters. The
120 is used for most everything else. So when the two live wires are
each carrying 200 amps, which is what the 200 amp rating means, the total
power is 240 volts x 200 amps, or nominally 48 KW, assuming unity power
factor.
>
> Something is seriously wrong with these numbers. My handy reference
> lists> the solar constant at 1340 W/m^2, and the mean radius of the
Earth
> is> 6.37x10^6 m. Multiply that out, divide by 3 billion people, and
you
> get an> approximate natural energy budget of 5.6x10^4 KW per person.
We
> should be> able to use whatever fraction of that we care to actually
harvest
> without> fear of creating a global heat problem.
>
> Billy Brown, MCSE+I
> ewbrownv@mindspring.com
>
Those numbers work out to 5.7x10^4 KW per person, modeling the earth as a
disk of the given radius, facing the sun. But the earth's population is
now reported to be 6 billion rather than 3 billion.
Ron Kean
.
.
.
.
___________________________________________________________________
Get the Internet just the way you want it.
Free software, free e-mail, and free Internet access for a month!
Try Juno Web: http://dl.www.juno.com/dynoget/tagj.
This archive was generated by hypermail 2.1.5 : Fri Nov 01 2002 - 15:04:57 MST