Make:

John writes - "Here's an interesting site about an early model of absorptive (heat driven) cooler. Some history, a little "where are they now" and includes a link to a mentioned DIY version. Caution: it seems to involve ammonia at 240psi...I wonder if a Hilch tube would be a better way to seperate the ammonia and water?"

From the site:
"When the hot ball is heated, for about 90 minutes, the ammonia evaporates first because it has a lower boiling point than water. The other cylinder is in water to help condense the ammonia in the cold ball. When the balls are fully charged, the cold ball is placed in the insulated box, as the ammonia evaporates to recombine with the water in the hot ball it removes heat, cooling the inside of the refrigerator for 24+ hours. A hole in the cold ball was for a special ice cube tray."

Crosley IcyBall - Link.