I know this is an old post, but I have been looking at this
myself out of curiosity.
It sounds like you could collect enough heat energy from solar to run
the absorption cycle, because you are heating ammonia water under
pressure, just enough to make the ammonia boil out, but not the water.
The critical temperature of ammonia is around 271 deg F, so it has
to be less than that, or the ammonia won’t liquefy at any pressure.
Here is a reference to a paper on a solar powered heat pump that uses
the ammonia absorption cycle:
http://tinyurl.com/2azv6f8
I didn’t buy the paper cause I am cheap, but there it is.
I think the main problem in getting it to work practically would be
some way to “throttle” the energy to provide a consistent, steady
heat source (like a propane burner) to make the ammonia absorption
cycle run efficiently. That implies some heat storage/heat exchange
system. Most storage mechanisms that would store that kind of heat
would be complicated and bulky, compared to carrying a bottle of propane.
For a fixed installation, however, it might be doable.
BTW, this is my first post and I am irritated by the damned Amazon ad
that floats over and blocks the right side of the posting block in my browser
(Firefox, Ubuntu Linux, 1024×768 resolution LCD). I am having to manually
size the width so I can see what I am typing. Hope it is readable.