Benedict White said:
Propane absorption? How does that work then?
Icy Ball
The best and simplest way to explain the workings of an absorption
refrigerator, is to explain how an icy ball works.
It is the for runner of an absorption refrigerator (kero, porta gas,
electric element) .
There are two steel balls, connected at the top by a steel pipe.
Inside the balls is a mixture of ammonia and water.
The balls are turned up so all the liquid runs into one ball, and then that
ball is heated, while the other is placed in a container of water to keep it
cool.
The ammonia is driven from the liquid, into the second water cooled ball
where it condenses into liquid ammonia.
After a period, you have water in one ball, and liquid ammonia in the
second.
The ball containing the liquid ammonia is placed in a specially build 'ice
chest' and the ball with the water in is located outside the 'ice chest'
Then the ammonia starts to evaporate, causing that ball to get quite cold,
the ammonia gas produced travels through the steel pipe into the ball with
the water. There it gets absorbed into the water.
The refrigeration effect will continue until all the ammonia has been
absorbed.
Then it is necessary to re do the heat and water in the container trick.
Absorption refrigerators work on the same principle, but are continuous in
operation, which is much more complicated, but in essence the same idea of
ammonia being absorbed by the water.
Some have some hydrogen in them to assist the flow.
Be aware that ammonia is nasty stuff, it burns, it explodes, it corrodes
copper etc hence the use of steel. Ammonia if it gets free creates extremely
strong alkaline solution when it gets into moisture, that will cause serious
injury, lungs and eyes are prime targets.
In places where ammonia is used there is special safety gear for the
protection of workers, one cannot speak to harshly of the effects of
ammonia. IE do not muck about with it.
Because of its toxic nature ammonia is NOT suitable for use as an air
conditioning refrigerant.
In air conditioning the absorption plants have water as the refrigerant, and
ammonia is not used.
In general the absorption system is very inefficient, and when used as an
air conditioning system, is usually heated by 'waste heat' from some other
process.
The absorption air conditioning units are temperamental and can 'stick'
causing problems.
They are fairly involved types of systems.
From memory a commercial system I was looking at years ago required twice
the heat input and to equal the cooling. IE 2.to 1 not att all efficient.
