[ExI] Asteroidal mining was Nukes was less expensive energy

[Dennis May]

In the early stages of space industrialization using
small automated mining and processing stations
dispersed will have the advantage of not needing
additional resources devoted to cooling.  Efficiency
will require heat dumps which will not exist in
many circumstances - particularly early on.
 
Another example of heat issues.  Many years ago
I heard talk of projections of how gray goo could 
consume planetary bodies in short order.  The projections
failed to take basic thermodynamics into account.
The friction generated by processing would have
turned the planetary body molten hot with no place
to reject heat for further processing.
 
Dennis

From: Dennis May <dennislmay at yahoo.com>
To: "extropy-chat at lists.extropy.org" <extropy-chat at lists.extropy.org>
Sent: Wednesday, September 21, 2011 10:31 PM
Subject: Re: [ExI] Asteroidal mining was Nukes was less expensive energy


Rejecting heat issues is why so many science fiction
space stories and movies are so far off base.  Their
ships and space stations would turn to toast in no
time whatsoever.  
 
Dennis

From: Dennis May <dennislmay at yahoo.com>
To: ExI chat list <extropy-chat at lists.extropy.org>
Sent: Wednesday, September 21, 2011 10:04 PM
Subject: Re: [ExI] Asteroidal mining was Nukes was less expensive energy


The cooling numbers I used were from space based
cooling radiator engineering.
 
It takes huge radiators for cooling industrial processes
in space.  Thus the interest in ice bodies where you
have a ready place to dump heat with the side
benefit of melting ice for radiation shielding and
water mining.

Dennis

From: Keith Henson <hkeithhenson at gmail.com>
To: extropy-chat at lists.extropy.org
Sent: Wednesday, September 21, 2011 8:46 PM
Subject: Re: [ExI] Asteroidal mining was Nukes was less expensive energy

On Wed, Sep 21, 2011 at 5:00 AM,   May <dennislmay at yahoo.com> wrote:

snip

Dennis, there is a vast literature on the subjects you have been
talking about, much of it where people actually worked the numbers.

Re cooling, there is rule of thumb number anyone can calculate on the
radiator area you need per kW of
 waste heat at room temperature.  I
suggest you might want to look up the formula and calculate it.

There is a subtle problem with scaling down heaters like induction
furnaces and scaling up radiators.

Best wishes,

Keith
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