Before 1834, the year the refrigerator was invented, food preservation consisted of simple methods like salting, spicing, smoking, pickling and drying. Of course, as we know now, none of those methods came close to competing with the refrigerator. But how does a refrigerator work? Simply put… your refrigerator has one job which is to keep the inside cold. And it accomplishes this by collecting heat from the inside of the refrigerator and releasing it outside.

When it comes to understanding how a refrigerator works, there are five main components to consider. The evaporator coil, condenser coil, expansion valve, compressor, and refrigerant. Inside the refrigerator the evaporator coils in charge of collecting heat and the condenser coil located on the outside is in charge of getting rid of it. These two components are connected to each other using what’s called a suction line and a Liquid Line. A chemical called a refrigerant flows through this system and its actually this fluid that is responsible for collecting the heat inside your refrigerator and transferring it out. By manipulating the properties of this fluid through the different stages of the cycle, we are able to move heat from one spot to the other. The expansion valve will allow us to decrease the pressure of the fluid. The compressor will be in charge of increasing the pressure of the fluid. Before we get started, its important to understand that “hot” always wants to move towards cold.

 For example, if you've ever been told during a hot summer day, “hey, kid….shut the door...you’re letting all the cold air out”. What you should have been told is, “hey,kid...shut the door...you’re letting all the hot air in” because “hot” always moves towards “cold”. So, we have a coil inside our box called the evaporator coil and one outside the box called the condenser coil. These two coils are connected using the Suction and Liquid line. Flowing through this system is a fluid called refrigerant. One important property for any refrigerant is to have a very low boiling point. R-22 ,a common refrigerant ,begins to boil at -40 celcius degrees, Yes this fluid begins to boil at a really cold temperature. 

Let's start at the compressor, at this point the fluid is in a low- pressure gas phase. The gas then enters the compressor and is compressed which increases the pressure. The gas leaves the compressor at a higher pressure then when it first entered. The now, high pressure, high temp gas flows towards the condenser coil. At the condenser coil stage, the gas begins to lose heat to the surrounding atmosphere...probably your kitchen. This is because the temperature of the gas's much hotter than the temperature of the air in the kitchen. By the time it leaves the condenser coil the fluid has lost enough heat that it cools and turns into a liquid. The fluid which is now a liquid makes its way towards the expansion valve.Which it enters as a high pressure liquid. The expansion valve expands the liquid which causes a sudden drop in pressure. 

Now the fluid leaves the expansion valve as a low pressure, low temperature liquid and makes its way towards the evaporator coil. As it passes through the evaporator coil - it picks up heat from inside the box which once again turns it into a gas. The fluid leaves the evaporator coil as a low pressure gas and heads towards the compressor   Which as we now know, is going to compress the gas; increasing its pressure and temperature. This cycle is repeated over and over to ensure the correct temperature is maintained inside the refrigerator. I hope you all enjoyed this article. Thank you for reading.Mind Motion out!