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Re: Gas powered Refrigeration?

To: shop-talk@Autox.Team.Net
Subject: Re: Gas powered Refrigeration?
From: Nick Jacobs <jacobs@flex.net>
Date: Fri, 09 May 1997 18:11:49 -0500
John Loftin wrote:
> 
>      The gas powered refrigeration is based on an "absorption cycle" (a
>      thermodynamic term).  In an absorption cycle, a secondary fluid, the
>      absorbent, is used to absorb the primary fluid, the refrigerant, after
>      the refrigerant has left the evaporator.  The vaporized refrigerant is
>      converted back to liquid phase in the absorber. 
How?  Is the absorbant cooled continuiously? ... only convection cooled
with static ambient air? ...I don't beleive there are any fans.
(especially in the case of the reader that had a kerosene powered
Refrig.)  If the absorbant is cooled, what moves the absorbant through
its heat exchanger? Or is there a chemical change when the refrigerant
and absorbant combine causing condensation of the refrigerant?


>      The solution of
>      absorbent and refrigerant is then pumped to the generator.
Pumped?


>      In the
>      generator, heat is added, and the more volatile refrigerant is
>      separated from the absorbent through distillation (this is where heat
>      is used for "cooling").  
Seems to be another point where heat has to be removed as needed for
distillation ...which I assume to mean re-cooling the solutoion to a
specific temp 
of condensation for the refrigerant (more volatile) but leaving the
absorbant in a gaseous? state. onegiven pressure temperature?
How is the solution cooled for the distillation?


>      The refrigerant continues to the condenser,
>      expansion valve, and evaporator, while the absorbent returns to the
>      absorber.
I'm still lost ... heat was added by the generator, which would have
created a higher pressure ...a possible source for refrigerant movement
through the expansion device, providing there's some kind of check valve
between the generator and the evaporator but my assumption about
distillation of the refrigerant would again reduce the pressure.  Maybe
this condensation cycle is at a higher temperature thus a higher
pressure still providing for a pressure diferential over the expansion
and "check" valves ...now that I think about it, the check valve
speculation can't be right ...I feel I am diverging from an
understanding again.  Can you turn me around?
 
> 
>         Absorption machines represent only a small percentage of
>      refrigeration systems in operation (not very efficient).  An
>      absorption machine is an excellent way to utilize waste heat (in
>      industrial applications).
> 

John, 
Thanks for your reply.
I don't mean to pick apart your explanation.  You just seem to know
about these systems and maybe you can see where I am getting off the
course of understanding them myself.

Corndog

-- 
For lack of a lace, a shoe was lost. 
For lack of a shoe, a soldier was lost. 
For lack of a soldier, a battle was lost. 
For lack of a battle the war was lost.

Corndog

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