i don't remember if it was homepower or mother earth news
but a few years back there was an article of an absorbtion system
that used rock salt and ammonia
they had a trough reflector and a 20ft section of schedule 40 2" blackpipe
it would take iirc about 3-4 hours of sunlight to drive the system, then it was covered so the refrigeration cycle could start
iirc they were making 20lbs of ice per cycle with it, which doesn't seem like
much until one considers that the villagers in africa had never seen ice before.
because rock salt has a fairly high melting point, i have considered using the exhaust heat from my trigenerator to drive the system to provide for refrigeration
and a freezer section
with the engine mounted low, and the refrigerator box mounted above it certainly could be made to work and make use of what is often times a waste byproduct.
with the intermittent nature of a cogen/trigen setup a rather large amount of chilling could be accomplished, maybe not enough for domestic airconditioning in
very hot climates, low insulated and large footage homes, but maybe in some climates
small well insulated homes it might be enough, or provide a significant portion of the airconditioning needs?
as for the ammonia, it is a tightly regulated substance, that one is unlikely to be able to just go in a purchase without a license in hvac, it is that way here in washington state.
my business partner got a cylinder of ammonia, but he has a state license which he had to produce to get through the hoops.
the upside is, most systems don't require that much ammonia, might be wiser just to have a certified hvac guy come out and charge the system.
thats what i figure on doing when the time comes.
also i am not crazy about having a homebuilt absorption system in the living space, so i figure to have my bulk refrigeration/freezer out in the engine shed seperate from the house anyway.
seperation of power and living space is very effective in mitagating insurance issues anyway, as well as code issues.
if you don't live in the engine room, and it is not attached to the house, code requirments are not much of an issue.
certainly the 48vdc limit does not apply codewise if you don't habitate with the power room.