From: John De Armond
Subject: Re: 2000 Springdale Keystone Dometic Refrigerator Dead
Date: Mon, 11 Oct 2004 14:22:02 -0400
On Mon, 11 Oct 2004 11:09:44 -0400, HDinNY <email@example.com> wrote:
>We would be better off if ammonia cooling systems were more
>common. Carrier has built systems for buildings for years
>and they probably are more energy efficient than compressed
>gas technology. Even Greenpeace thinks so;
Those who ignore history are doomed to repeat it. Never more true here.
Greenpeace shows its typical disdain for human life over worship of the
Gia god of nature and other fantasies. Citing Greenpeace as an authority
for anything pretty much dissipates any credibility one ever had.
The halogenated hydrocarbon refrigerants (freons) were developed precisely
because of the body count extant from ammonia and other toxic and/or
flammable refrigerants in common use back then. Ammonia refrigeration was
typically used in the only place in town that had air conditioning - the
movie theater. Enough casualty causing leaks happened that the race was
on to find a safe replacement. DuPont got lucky and won the race.
Ammonia systems are common for large low temperature operations such as
frozen food processing and warehousing. The required safety equipment and
designs make the cost prohibitive for smaller application.
Ammonia is not allowed for comfort cooling - even indirect systems where
the ammonia system cools glycol - for the simple reason that ammonia is
extremely soluble in water and the resultant mix is very basic. It
quickly corrodes the light metals and copper used in glycol systems. The
result is the very real risk that an aqua-ammonia solution could spray
through corrosion leaks in the chiller coils into the airstream.
I spent a summer running an ammonia ice plant for a concrete batch plant
when I worked for TVA. I'd not want to go back to that again. Even
though the equipment shed had two open sides and we did everything we
could do to find and fix ammonia leaks, I spent my working hours in a
supplied air mask. Not fun.
So that the two don't get mixed up, the kind of ammonia refrigeration is
completely different from the absorption units used in our RVs. This type
of system is a conventional Carnot cycle with a compressor, evaporator,
condenser and expansion device. It simply uses ammonia instead of freon.