The Inner Workings of the Refrigerator
The refrigerator works in similar fashion to a home's central air conditioning system, but on a much smaller scale. It features a condenser, a compressor and an expansion valve. It also has a closed system of coils in which is contained the gas or refrigerant. A chemical gas called tetrafluoroethane, or HFC-134a, is the standard refrigerant found in most refrigerators sold today.
How the Refrigerator Works: Part 1
When you turn the temperature dial down on the inside of your refrigerator, the thermostat turns on the compressor motor.The gas inside the compressor is then squeezed, or compressed. As the gas is compressed, it begins to generate heat. With the gas now compressed and extremely hot, it passes from the compressor through the coils where it slowly begins to lose some of its heat. The heat is released into the surrounding room air. That is why you feel heat eminating from underneath or behind your refrigerator. Additionally, as the gas cools, it eventually turns into a liquid.
How a Refrigerator Works: Part 2
When the refrigerant enters the condenser, all of the remaining heat is removed from it, and any remaining gas is compressed into a liquid state. With the refrigerant now in liquid form, it is pushed through the expansion valve. The opening on the expansion valve is so tiny that as the liquid is forced through it, it immediately reverts back into a gaseous state. When this occurs, the gas becomes extremely fast-moving and very cold. The frigid gas then travels through the coils on the inside of the refrigerator. As the gas in the coils begins to evaporate, it absorbs heat from the environment inside the refrigerator, thus cooling down the inside of your fridge. Most refrigerators feature a fan that blows air through the coils to force cold air into the chamber. After the gas runs through the inner coils, it eventually returns to the compressor to begin the cycle again. The process repeats itself until the inside temperature of the refrigerator satisfies the thermostat's setting and then the system is shut down until the thermostat calls for it to run again.