X-Message-Number: 2143
Date: Thu, 22 Apr 93 00:23:08 CDT
From: Brian Wowk <>
Subject: CRYONICS Ballast Containers

Steve Harris:
 
> ..., another possibility is the stackable
> cubical 5 gallon plastic jugs sold as emergency water supply
> containers in survival stores.  These might have to be pre-
> frozen before capping to prevent rupture, but after that should
> work okay (say-- does anyone make a simple valve which passes air
> but excludes liquid?).
 
        I'll bet those would work fine even completely sealed before 
freezing.  Plastic tolerates freezing expansion remarkably well.  I 
recently tried to burst a 500ml plastic vitamin bottle by freezing it 
full of water as a demonstration for my wife's 2nd grade students.  
The darn thing wouldn't burst.  It just got very fat.  Those 5 gallon 
plastic jugs (if I'm thinking of the right ones) aren't even rigid.
 
        Regarding cooling water: I do not think refrigerating only at 
night is a good idea.  Even with lots of ballast, this will cycle the 
room temperature by 0.5'C every day.  If you relied on nighttime air 
cooling of water in a reservoir for daytime use, you would need a 
10,000 liter reservoir-- an expensive project in itself.  I think 24-
hour ground cooling is the best solution.  Let the Earth be our 
reservoir.  We then don't impose any load on the building air 
conditioner either.  We will also be less vulnerable to terrorists or 
other kooks who might want to take pot shots at roof-based hardware.
 
        Can anyone tell me what the summertime ground temperature 
profile looks like in Arizona or Nevada?  To design an underground 
water cooler, I would also need to know the approximate thermal 
conductivity of dry sand or soil.     
 
                                                --- Brian Wowk

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