The most famous physicist of the twentieth century wasn't a prolific inventor a la Thomas Edison. The fridge would prove to be one of Einstein's few forays into the world of commonplace engineering.
-Randy Alfred, Mad Science (2012)
In the early twentieth century, Einstein teamed up with fellow nuclear scientist Leo Szilard in an effort to use science to advance humankind in the industrializing world. In political history, the two are remembered for penning a letter to U.S. President Franklin Delano Roosevelt (FDR) in 1939. Known as the "Einstein-Szilard letter," the correspondence urged FDR to initiate research into nuclear weapons, fearing the Nazis would discover atomic bombs first. The letter resulted in the Manhattan Project.
The entanglement in the development of nuclear weapons fits the profile of Szilard, who conceived of nuclear chain reaction in 1933 and patented a nuclear reactor a year later. Szilard also actively participated in the Manhattan Project, but Einstein had reservations. He questioned the ethical use of nuclear fission as a weapon - evidenced in 1955 by the "Russell-Einstein Manifesto" - a letter written by British philosopher Bertrand Russell that denounced the nuclear arms race and called for international peace. Einstein signed the document just days before his death. Although Einstein is remembered for his theoretical mastery, the man left a more practical legacy in the science of appliances.
For the last decades of his life, Einstein sought unity, a concept he explored abstractly in his "unified field theory." More practically, Einstein applied his knowledge to simple machines meant to advance the state of the world. As a physicist, Einstein was keenly aware of energy exchanges and, for humankind, energy usage. Even in the early industrial era, when machines seemed unstoppable, Einstein understood the value of self-sustainable energy - the balance between use and renewal. In 1930, Einstein with his colleague Szilard developed a refrigerator that required no electricity. The refrigerator used only a simple heat source and the chemical reactions of ammonia, butane, and water. Randy Alfred has explained the process:
Ammonia gas is released into a chamber with liquid butane in it. This reduces the boiling point of the butane, causing it to evaporate and draw in energy from the environment, cooling the area outside the evaporator. The mix of gases passes through a condenser filled with water. The ammonia dissolves into the water, and the butane condenses into liquid, which sits atop the water-ammonia mixture. The butane runs back into the evaporator, a heat source is used to drive the ammonia back into gas, and the ammonia heads to the evaporator to begin the cycle again. (Mad Science, p. 317).
The Einstein-Szillard refrigerator was innovative because it used neither electricity nor Freon, making it an appealing alternative for poor, rural areas. But, compared to modern refrigerators, it did not cool items as efficiently. According to Alfred, "At last report, however, Oxford researchers were working to quadruple the cooling output." The Swedish appliance company Electrolux has licensed some of the patent, and the Einstein-Szilard refrigeration cycle has been used to build small coolers.
Although Einstein only pursued two American patents in his lifetime (the other for a self-adjusting camera), he introduced energy efficiency to the refrigeration industry - an initiation that will surely grow in importance as the marketplace moves toward sustainability.
You see, there is genius behind every refrigerator, and genius on every refrigerator. How do you show your intelligence (academic, social, or emotional) on your refrigerator?