Xref: utzoo talk.politics.misc:8772 sci.misc:1264
Path: utzoo!mnetor!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!ssc-vax!eder
From: eder@ssc-vax.UUCP (Dani Eder)
Newsgroups: talk.politics.misc,sci.misc
Subject: Re: greenhouse effect / solar power satellites
Message-ID: <1835@ssc-vax.UUCP>
Date: 5 Apr 88 02:30:06 GMT
References: <34557@kestrel.ARPA> <2430@umd5.umd.edu> <2116@mit-amt.MEDIA.MIT.EDU> <22678@bbn.COM>
Distribution: na
Organization: Boeing Aerospace Corp., Seattle WA
Lines: 41

In article <22678@bbn.COM>, eli@bbn.com (Steve Elias) writes:
> 
> 	regardless of the efficiency of any of the ground receiver systems,
> 	solar power satellites would add incredible amounts of energy to
> 	the earth/atmosphere system, whether in the form of electricity,
> 	or in the form of waste heat.  this is their function.
> 	the form the energy takes is not relevant to the global thermal
> 	considerations.
> 
> 	my point isn't that we have to minimize waste heat -- it is that
> 	we have to minimize the amount of energy that enters the earth
> 	ecosystem that would not otherwise be there. 
> 
If you are concerned about heat balance, have you considered tar-paper
roofs and asphalt roads?

Let us do some ROM calculations.  Your typical suburban home has
about 160 square meters of roof.  Most roofing materials are darn
good black body absorbers.  Your average temperate latitude home
receives 125 Watts of insolation/sqaure meter, over 24 hours.
Let us say the roof absorbs 40 watts more than the original cround
cover.  Thus, the suburban home adds someting on the order of 
6.4 kilowatts to the earth's heat balance.

This equals the installed electrical generating capacity per household
in the US.  There is something like 300 square meters of road for
every household in the US.  In addition, there is a parking spot
for every car at a location other than the owner's drivewaay
(only that counts, since the car always covers some part of the ground
when outdoors)

That adds at least another 30 square meters per household.  Assume
that the same change in absorbtion occurs as for roofs.  We are
talking several times the effect of the roofsa.  In fact, when one
looks at Landsat photographs of city areas, the cities stand out
as dark splotches.  And many city dwellers are familiar with the
temperature differential from city to suburb.  What most are nmot familiar
with is the trend continues into the rural areas.  It is partly
waste heat and partly darker ground cover.

Dani Eder/Boeing/Space Station Program