It’s so hot and I’m grateful to have them but how do they actually create the cold without ice or anything?
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Liquid refrigerant! Air gets sucked in and passes over the coils and then gets blown through the home.
When you squish a gas, it heats up. When you squish it until it liquefies, it heats up even more.
If you release it, then it returns to being a gas and cools back down.
What if, before you let it expand, you let it cool down and shed its heat to its surroundings? Then, when it cools back down, it gets quite cold instead of returning to its original temperature.
If we take a fluid and do this to it repeatedly, shedding its heat outside of your house and then while it’s cold it cools down the air inside, it keeps your house cold. So long as the pump keeps running it’ll keep cooling the house.
Short answer – it doesn’t. You cannot create cold, cold is the place where heat is not. So instead air conditioners move the heat to outside of your house. That’s what that condenser unit outside that blows out hot air is for – it’s the place all the heat in your house goes.
Air conditioners and refrigerators work on the same basic setup. They work by absorbing heat from the inside of the room/home/refrigerator, and discharging it outside. Refrigerant is the medium or carrier of the heat.
On the inside of the home (or inside fridge) is an evaporator coil. It gets cold because cold refrigerant is flowing through the coil’s piping. As warm air from the home is blown across that evaporator coil, the cold refrigerant absorbs the heat that’s blowing across it.
The refrigerant, having absorbed heat, travels through a pipe to the outside condensing unit, where the heat is ultimately discharged through the condensing coil outside. The condensing coil for a refrigerator is usually attached to the back where you can’t see it.
The compressor acts as the pump that pushes the refrigerant through the system’s piping and coils.
This is the easiest explanation before you have to wrap your head around the physics of refrigerants and how they change phase between liquid and gas inside different sections of the system.
Many different chemicals — including water – can be used as a refrigerant. We use modern refrigerants like Freon because they have very low boiling points and can carry and transfer heat efficiently.
The biggest takeaway for you is that cold isn’t something that’s “created.”
Cold is how much something is “not hot.” You can create heat, but cold is the lack of that heat. If you take away heat (energy) things get colder.
So AC takes heat from the cold side and moves it somewhere else. That’s why AC units have vents outside, to vent out the heat to atmosphere.
Now how that works is there are two “coils” which just like they sound are two tubes. If you fold them out, it’s just a big circle with two parts that break it up, on opposite sides of each other. Between them, there’s a valve on on one side and a compressor on the other. The compressor compresses a gas into a liquid, the valve lets liquid out so it can become a gas.
Gas has more energy than liquid, so when you go from gas to liquid, you need to give off energy, or heat. When you go from liquid to gas, you need to take in energy, so you take it from the air.
That air with less energy is colder, so then your AC unit blows that into your house.
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