That’s an Icy-Ball (and a younger Dean) in a photo from ARC in 1994. Dr. Larry Winiarski and I built 18 somewhat scary prototypes and eventually made ice. We had replicated a pre-rural-electrification 1920s ammonia/water absorption refrigerator.

A fire heats the water/ammonia mixture and separates the ammonia out of the water (it turns into gas at a lower temperature). Then the pressure in the sealed system rises until the ammonia gas becomes a liquid. The Icy-Ball is taken off the fire and the small ball (full of liquid ammonia) is placed in an insulated box that has water (we made ice cubes) in it. The pressure in the system goes down and the liquid ammonia turns into gas robbing heat from the insulated box which freezes the water. The ice in the box cools food in the non-electric refrigerator. 

The basic absorption cycle function of this 1920s appropriate technology is still in use today in RV and Camper fridges, and in developing countries.

How amazing to make ice from fire!

Read more about it here: https://en.wikipedia.org/wiki/Icyball