siliquasquama:

theaudientvoid:

People joke about how flight is effectively the real life equivalent of the half a-press meme, because One Weird Trick with air pressure allows giant hunks of metal to fly. But refrigeration is an equally absurd physics hack. Like, for all of human history, the only real way to cool something besides just allowing the heat to dissipate naturally was to use apply cold stuff to the hot thing, and have it absorb some of the heat. But cold stuff is, by definition, scarce in hot environments, and is used up by this process. And that was how cooling worked for all of history, until some assholes in the 19th century figured out One Weird Trick with vapor compression that can allow you to generate an unlimited amount of cold stuff (well, limited only by your ability to continuously compress and decompress the refrigerant). Like, fuck off…

Not quite! People have been refrigerating things and even freezing things using simple evaporative cooling for a very long time. Like the Persian cooling towers called Yakchal.

You dump water in a pit in the floor in the winter, and the wind blows over the hole at the top and carries the last heat of the water away so it freezes. Then the yakchal stays cold over the summer so you have ice all year round. Sometimes these things had wind towers installed that could use the wind to freeze water even in the middle of summer.

Then there’s this thing – 

The Botijo, an old Spanish design that lets enough water bleed through the clay that the wind evaporates it and cools the whole container.

So people have been taking advantage of the wind for a while, and where it works, it works much better than ice, because ice can only get something as cold as itself. If it steals heat from something, it melts in turn. But the wind can carry away as much heat as it wants.

That’s the old cheat code. Refrigerators just automated the process to make it constant and reliable.

Leave a comment