Concept
The Einstein–Szilard or Einstein refrigerator is an absorption refrigerator which has no moving parts, operates at constant pressure, and requires only a heat source to operate. It was jointly invented in 1926 by Albert Einstein and his former student Leó Szilárd, who patented it in the U.S. on November 11, 1930 (). The three working fluids in this design are water, ammonia, and butane. The Einstein refrigerator is a development of the original three-fluid patent by the Swedish inventors Baltzar von Platen and Carl Munters. From 1926 until 1934 Einstein and Szilárd collaborated on ways to improve home refrigeration technology. The two were motivated by contemporary newspaper reports of a Berlin family who had been killed when a seal in their refrigerator failed and leaked toxic fumes into their home. Einstein and Szilárd proposed that a device without moving parts would eliminate the potential for seal failure, and explored practical applications for different refrigeration cycles. Einstein had worked in the Swiss Patent Office, and used his experience to apply for valid patents for their inventions in several countries. The two were eventually granted 45 patents in six countries for three different models. It has been suggested that most of the actual inventing was done by Szilárd, with Einstein merely acting as a consultant and helping with the patent-related paperwork, but others assert that Einstein contributed design work to the project. The refrigerator was less efficient than existing appliances, although having no moving parts made it more reliable; the introduction of non-toxic Freon — later found to be responsible for serious depletion of the Earth's ozone layer — to replace toxic refrigerant gases made it even less attractive commercially. The Great Depression of 1929 dried up funding for development, and the widespread political violence in Nazi Germany, where the inventors lived, particularly towards Jews such as Einstein and Szilard, contributed to the device's lack of commercial success.
