How does a fridge work?

Modern refrigerators don't use CFC because CFCs are harmful to the atmosphere if released. Instead they use another type of gas called HFC-134a, also called tetrafluoroethane. HFC turns into a liquid when it is cooled to -15.9 degrees Fahrenheit (-26.6 degrees Celsius).
A motor and compressor squeezes the HFC. When it is compressed, a gas heats up as it is pressurized. When you pass the compressed gas through the coils on the back or bottom of a modern refrigerator, the warmer gas can lose its heat to the air in the room.
Remember the law of thermodynamics.
As it cools, the HFC can change into a liquid because it is under a high pressure.
The liquid flows through what's called an expansion valve, a tiny small hole that the liquid has to squeeze through. Between the valve and the compressor, there is a low-pressure area because the compressor is pulling the ammonia gas out of that side.
When the liquid HFC hits a low pressure area it boils and changes into a gas. This is called vaporizing.
The coils then go through the freezer and regular part of the refrigerator where the colder liquid in the coil pulls the heat out of the compartments. This makes the inside of the freezer and entire refrigerator cold.
The compressor sucks up the cold gas, and the gas goes back through the same process over and over.