In the 1920s newspapers reported that a Berlin family had been killed when a seal on their refrigerator broke and toxic fumes from the refrigerant leaked into their home. This motivated Einstein and his former student Leo Szilárd to work on an improved refrigerator.
The fruits of their labour can be found in US Patent 1781541 which proposed an absorption based refrigerator which is a refrigerator that uses a heat source to provide the energy needed to drive the cooling system. The Einstein/Szilárd fridge had no moving parts and operated at constant pressure.
More than 45 patent applications were filed in six different countries relating to the fridge but Einstein and Szilard’s invention never became a commercial product because Freon, a non-toxic refrigerant (to humans at least) was introduced in the 1930s which was more easily compatible with existing fridge designs.
The technology was licensed however which provided a nice little earner for the scientists.
Incidentally, the development of Freon involved the American mechanical engineer and chemist Thomas Midgley Jr. who had an interesting way of demonstrating that products were safe. Is Freon safe? Try inhaling a lung-full and breathing it out onto a candle. Is lead petrol safe? Try inhaling a lung-full daily for 60 seconds.
Thomas Midgley – a man for who Health & Safety clearly only meant ensuring his tie was held out of harm’s way when bending over the gas rings to light a cigarette!