Refrigerators work on complex scientific principles and rely on devices like compressors, condensers, capillaries, and evaporators to maintain the temperature inside. We take them for granted, but when they break down, we realize that we have no alternative, and we realize how important they are.
It may seem like a simple matter of moving the food to another location where the temperature is low enough to solve the problem. However, in the average home, it’s almost impossible to find a place that can maintain the same temperature as a refrigerator, unless it’s the winter months. So, when this happens, there’s little you can do but fix the refrigerator. This is when we realize how precious an invention the refrigerator is that we take for granted every day.
So why isn’t it easier to find a place with a similar temperature to your refrigerator? Many people know from experience that it’s harder to lower the temperature than to raise it. While raising the temperature is as simple as lighting a piece of paper on fire, lowering it is not so simple. This can be explained by the second law of thermodynamics. According to the second law of thermodynamics, in an isolated system, the total entropy is always increasing or constant and never decreasing. This can be interpreted as the directionality of energy transfer, meaning that it is natural for heat to move from higher to lower temperatures, but not vice versa. For this reason, humans have been using fire to generate heat for a long time, but it’s only recently that we’ve started to utilize cooling technologies such as refrigerators. So, how do refrigerators work and how do they reduce the temperature inside?
A refrigerator is a device that maintains a temperature that’s one to two degrees Celsius below the normal room temperature of everyday life. In order to do this, it has to take heat from the inside of the refrigerator to the outside to lower the temperature inside and maintain it. However, it’s not enough to simply remove the heat once. As soon as the inside temperature is lower than the outside, the heat from the outside is transferred back into the refrigerator, causing the temperature to rise. Therefore, the refrigerator must constantly repeat the process of transferring heat from the inside to the outside. In other words, the refrigerator is a device that maintains its internal temperature by transferring heat.
To understand this process, we need to look at the structure of a refrigerator. A refrigerator consists of a compressor, condenser, capillary tubes, and an evaporator, all of which contain a substance called refrigerant. Refrigerant is a substance that is responsible for transporting heat from the inside of the refrigerator to the outside. When sweat or water evaporates, it takes heat away from your skin, which is also a type of refrigerant. The refrigerant in your refrigerator circulates in this way, moving heat from the inside to the outside. Now, let’s take a look at each step of the process
The compressor is the device that circulates the refrigerant by putting pressure on the gaseous refrigerant. If the refrigerant is the blood, the compressor is the heart. Compressors need power to pressurize the refrigerant, which is why our refrigerators use electricity. Under pressure from the compressor, the refrigerant rises in temperature and becomes highly compressed. This compressed refrigerant travels to the condenser, where it circulates inside the refrigerator.
The refrigerant travels to the condenser, where it condenses from a gas to a liquid. The condenser is against the outside of the refrigerator, where the compressed, hot refrigerant is much hotter than the outside temperature. As the refrigerant passes through the condenser, heat is transferred from the refrigerant to the outside, and the refrigerant loses heat and turns into a liquid. This is why we feel warmth on the outside of the refrigerator.
After passing through the condenser, the refrigerant passes through capillaries. Capillaries are made up of thin tubes, where the refrigerant is subjected to reduced pressure. In this process, the temperature of the refrigerant also decreases. The velocity of the refrigerant increases as it passes through the capillaries, which can be explained by Bernoulli’s principle. As the velocity of the fluid increases, the pressure decreases, which causes the refrigerant to turn into a low-temperature, low-pressure liquid as it passes through the capillary.
After passing through the capillaries, the refrigerant travels to the evaporator. At this point, the refrigerant is cooler than the temperature inside the refrigerator, and it absorbs heat from the inside. After absorbing the heat, the refrigerant turns back into a gas and the internal temperature drops. The refrigerant returns to the compressor and repeats the same process, maintaining the temperature inside the refrigerator.
So far, we’ve seen how a refrigerator works, its internal structure, and the role of each component. You can see that keeping the temperature inside a refrigerator low is a more complex and scientific process than you might think. This is the moment when we realize that the refrigerator that we take for granted every day is actually a brilliant invention that was the result of research and experimentation by engineers. The next time you open the door of your refrigerator, it’s a good idea to thank the people who created it for their hard work.
