US Patent 7490482 Absorption space cooler with no forced pumping

A two-liquid absorption refrigerator or space cooler of the cyclic type uses a spiral shaped Bourdon Tube as the refrigerant gas generator, with the lower end of the spiral disposed at a heat source. The generator may also function as the absorber vessel, thus greatly simplifying the operation of the device. In use, when ammonia depletion during the cooling cycle allows the generator to heat, it moves its lower end to a position removed from the heat source and begins to cool, thus allowing a charging cycle to replenish ammonia into the absorption liquid (usually water) in the generator. The device may thus function with only one moving part and without electricity, and further without control over the heating source.