How Your Refrigerator Works
Image Source: Stuff Nobody Cares About
There’s a reason your grandmother called the refrigerator an “icebox”: in the 1920s, most people kept food cool by putting it inside a box under a block of ice that had to be delivered daily by a truck. Early refrigerators like Frigidaire, a GM-owned brand, used coolants and pumps to produce low temperatures without the ice.
These coolants must be volatile, inert, and cheap. Early cooling units used water, which isn’t inert and is in fact a powerful solvent; or ammonia, which is plenty volatile, but smells bad and can poison people at high exposures. By the early 1920s, GM was looking for a new chemical that would meet all three of the desired criteria.
Ideally without ending life on Earth. Image Source: Blogspot
Enter Thomas Midgley Jr. He knew that a class of compounds called alkyl halides met both of the first two criteria, so the search began for a chemical in this class that would be cheap and non-toxic.
Eventually, Midgley’s team settled on dichlorodifluoromethane, which is simply a mix of truly awful chemicals. Chlorine, for example, is so toxic on its own that it was used as a weapon during World War I. Methane is highly flammable. As for fluorine, well…just have a look at what it does when it’s free to bond with iron:
The trick to making dichlorodifluoromethane, or “Freon,” as it conveniently became known, is to use all of the constituent elements’ most hazardous features against each other to achieve some kind of balance. It worked; the compound was safe for home use, but not at all safe for the environment.
Next up: How exactly we put the hole in the ozone layer…
