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 and patented in the US on November 11, 1930 (U.S. Patent 1,781,541). This is an alternative design from the original invention of 1922 by the Swedish inventors Baltzar von Platen and Carl Munters.
From 1926 until 1933 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 used the experience he had gained during his years at the Swiss Patent Office to apply for valid patents for their inventions in several countries, the two eventually being granted 45 patents in their names for three different models.
It has been suggested that most of the actual inventing was performed by Szilárd, with Einstein merely acting as a consultant and helping with the patent-related paperwork.
The refrigerator was not immediately put into commercial production, the most promising of their patents being quickly bought up by the Swedish company Electrolux. A few demonstration units were constructed from other patents.