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These days, Albert Einstein’s name is practically synonymous with genius. He’s best known for his theory of general relativity and sometimes as a man who enjoyed fruit. Or at the very least, most people know him for the E=mc² formula. But he also dabbled in fields beyond physics, including inventing. He held about 50 patents, including one for the Einstein-Szilard Refrigerator, developed with fellow physicist Leo Szilard in 1926.
You might think a man recognized as one of the smartest humans of all time must have created an amazing refrigerator, but history has all but forgotten it. Einstein’s fridge ran on three fluids: butane, ammonia, and water. It replaced the traditional compressor of a normal refrigerator with a pressurized system that didn’t need any moving parts. Ironically, all you needed to run it was heat.
When heat is applied, the ammonia in the system lowers the boiling point of the butane, and the butane boils and evaporates. This process is an endothermic reaction because it absorbs heat from inside the fridge, cooling the surrounding area. The butane gas reaches the water, where it cools down and condenses to liquid once more. Then, the ammonia lowers the boiling point again, and the butane repeats the boiling process. The cycle continues in a closed system of tubes, keeping the refrigerator box cold inside as long as the system is running.
Why would Einstein design a fridge?
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In Einstein’s day, home refrigeration was relatively new. The technology was still unreliable, and there were tales of refrigerant chemicals leaking from pump mechanisms into people’s homes. While living in Berlin in 1926, Einstein read the story of an entire family who had died in their sleep when their refrigerator broke and leaked toxic gas into the house.
At the time, refrigerant chemicals were highly toxic and included ammonia, methyl chloride, and sulfur dioxide. Freon, which was safer by comparison, didn’t come into widespread use until the 1950s, and it was later phased out as well. Einstein wanted a way to save lives, so he designed a self-contained unit with no moving parts. The goal was to eliminate leaks and, in doing so, save lives.
Unfortunately, Einstein and his partner faced a number of challenges. For one, the system wasn’t entirely efficient. Though it was designed to be safer, the system still relied on dangerous gases like ammonia and butane. While it was designed to remain sealed, a leak could have posed serious risks. The Great Depression in Germany, along with the rise of the Nazi party, cut off the duo’s funding. Both men fled the country and shifted their focus to other concerns. The refrigerator was cast by the wayside and never went into production.
In 2008, researchers proposed changing Einstein’s design. They suggested that, with different gases, it could be four times more efficient and just run on solar power — which can also be used to cook food. But so far, traditional compressor fridges remain the most popular option. Maybe in the future, with an eye towards greener technology, Einstein’s idea will have a resurgence.