How Do Refrigerators Keep Things Cold?

Refrigerators use the laws of heat transfer to keep certain compartments cold, channeling heat away from the air and into a gas that is pumped through the inner workings of the refrigerator. The gases used for this process have varied over time, but today most are of a specific composition that allows them to absorb heat easily while also being easy to compress.

Compressor

Although all the components of the refrigerator work together, the compressor and the gas flowing through it are probably the most important parts. Refrigerators work by absorbing heat with a particular kind of gas, and then releasing this heat again by manipulating the gas. It is the compressor's job to compact this gas into a hot, high-pressure state that holds a large amount of energy in a small space. Particular gases that can hold a large amount of heat and become pressurized easily are used.

Condenser

The hot, high-pressure gas is then passed along to a condenser, which takes the energy from the gas and channels it along metal fins away from the refrigeration compartment. Heat moves very easily through metal under the proper conditions, and the fins are designed to siphon away as much heat as possible. The compressed gas, once hot, is now drained of energy and no longer has the ability to maintain a gas state. So it collapses into a liquid instead, and this liquid is passed into the evaporator coils.

Evaporator

Liquid refrigerant gas is no good to the process, so the evaporator is used to turn it back into a gas. It does this by giving the liquid space and a small amount of heat. Since refrigerant is most comfortable in a gas state, it very quickly boils with this heat and evaporates itself back into a gas, this time a low pressure version with more far-flung molecules that take up more space. Since only a small amount of heat was used and the gas in not compressed, it is now very, very cold.

Capillary Tubes

Capillary tubes are the structures that channel the gas from place to place throughout the refrigerator. Once these tubes have taken the gas through the evaporator, they passed through the refrigerator compartment itself. Heat always flows to try and reach equilibrium, so it naturally leaves the air of the compartment and enter the gas in the capillary tubes. This warms the gas as it passes by, and increasingly cools the air of the refrigerator. The gas is then taken back to the compressor.

Thermostats

Of course, refrigerators need to be very specific, especially those used to keep particular types of food fresh. This is why most of them come equipped with thermostats that keep track of the temperature of the compartments and adjust them to make sure they stay at the proper levels. Refrigerators usually work in cycles of the above process, and intervals between these cycles are shortened or quickened based on what adjustments need to be made.

References

• How Does A Refrigerator Work?
• How Do Refrigerators Work?
• How Refrigerators Work

Resources

• How Refrigerators Work