[jeff5may]

The thing with the thing you ponder is the "icy ball" cooler. Spent material is regenerated with heat and the high-temp, high-pressure gas is captured in a closed container. This container is either sealed and removed, or a valve is closed, when the heat source is removed. The pressure and temp of the sealed container drops, and the container becomes a "Heat vacuum" until all of the captured gas evaporates.

The next step in improving the process is eliminating moving parts. This is the Einstein Refrigerator design, which was the driving idea behind the RV fridge. They absolutely work, and last like the Energizer bunny. No moving parts in the refrigeration circuit, all it needs is a heat source above 150-175 degF to boil the weak solution. Various solutions can be used, the two most common are are anhydrous ammonia or lithium bromide and water.

A third material is used to reduce the partial pressure of the working solution. This can be hydrogen, butane, propane, freon, etc. When building a DIY unit, the refrigerant circuit is evacuated and the vacuum is broken with this third material (just like a heat pump). The working solution is pumped in afterwards, so there is no non-condensing gas in the system. There you have it, run it like you stole it.

The problem here is in the details. How much of what to charge the system with is important. As with the other technologies in this industry, details are well known inside the circle, but not easy to find outside it. Also, ammonia and lithium chloride/bromide are highly corrosive, so copper and brass fittings are not appropriate. Would-be innovators have been running into the regulation wall associated with underwriting and safety requirements, and most have not produced a unit that could be mass-produced or copied easily.

Any members with experience in this realm of ammonia or lithium bromide chiller/freezer operation, please chime in here with details. There is an abundance of "eager beavers" posting sparse tidbits of design and fab data on the net, but not really anything resembling complete plans or parameters to begin with. I can think of no better place to aggregate this subject and help the "makers" out there get a heads up to begin assembling monsters in garages and shops at large. As always, pats on the back rule over financial rewards.