Cryocoolers

When things get very cold, they become very, very cold. Cryocoolers are like special machines that make things really, really cold on purpose. They work kind of like a fridge, but instead of keeping your food cold, they keep special things called “cryogens” cold.

A cryocooler has a few parts that work together to make things cold. First, there is a special gas called a “refrigerant” that gets pumped around the different parts of the cryocooler. This gas is really good at carrying heat away from things, kind of like a vacuum cleaner sucks up dirt.

There is also something called a “compressor” that squishes the gas to make it hot. By squishing the gas, we can make it release heat. This is kind of like how your bike pump gets hot when you use it – you’re squeezing air into the tire, and that makes the air heat up.

The refrigerant gas then flows through a special tube called an “expansion valve.” This makes the gas expand, which cools it down a lot. Think of it like a balloon – when you let go of the end, the air rushes out and gets really cold. That’s kind of what’s happening in the expansion valve.

With the refrigerant gas now super cold, it can be used to cool down other things we want to keep cold, like the “cryogens” we mentioned earlier. These cryogens are special liquids or gases that can be very useful when they are cold, like for making super-strong magnets or for keeping things cold in space.

So when we put everything together, a cryocooler can make things super cold by pumping a refrigerant gas around, squishing it to make it hot, then letting it expand to make it super cold, and finally using that cold to cool down cryogens for special applications.