Wednesday, September 1, 2021

How does a refrigerator or fridge works?

Have you ever thought how does a refrigerator or fridge works? How it keeps our food and other stuff cool even in the intense heat of summer? In this article we will discuss about the parts of a refrigerator, and how these parts work together to keep our food and other stuff cool inside the refrigerator. So let us start!

Components of a refrigerator

First of all let us talk about the components of a refrigerator.


Refrigerants is also known as coolant. It is a chemical that is capable of changing its state between a hot gas and a cool liquid. Basically it is the liquid that keeps the refrigeration cycle going. Some common examples of refrigerant are ammonia, R-290 and R-600A.


Known as the “heart” of a refrigerator, a compressor basically consists of a motor, and it helps in circulating the refrigerant throughout the system. The motor of the compressor compresses the refrigerant in a cylinder to make a hot and high-pressure gas.


The condenser is located on the back of a refrigerator, and consists of a coiled set of tubes with external fins. The condenser makes the refrigerant to cool down and helps in the liquefaction of the refrigerant, which means it turns refrigerant from gas to liquid again.


The evaporator is located inside a refrigerator and it consists of finned tubes, which are made up of metals with very high thermal conductivity, that helps in absorbing heat. It is the part of the refrigerator that makes the stuff stored in the refrigerator to cool by absorbing heat from material kept inside. Due the heat from the material kept inside the refrigerator, the refrigerant turns from a liquid into a gas.

Expansion valve

An expansion valve consists of a thin piece of tube also known as capillary tube, which controls the flow of the liquid refrigerant into the evaporator. The liquid refrigerant is passed through the capillary tube and then sprayed into the low-pressure environment of the evaporator. This valve is very sensitive to temperature changes of the refrigerant.


This device controls the cooling process by analyzing the temperature inside a refrigerator. It basically turns off the compressor when the sensor senses that it’s very cold inside the refrigerator, and turns on the compressor if it senses too much heat inside the refrigerator, so that the cooling process begins again.

How does a refrigerator or fridge works?

Talking about the working principle of a refrigerator, we know that if we compress gases into less volume then the gases get hotter because we have to work to push their energetic molecules together and this work is converted into increased temperature of the gas. Similarly, if we expand a gas, it suddenly occupies much more volume and the heat energy its molecules contain is then divided over a bigger volume of space, so the temperature of the gas falls and it gets cooler. This phenomenon of cooling and heating of gas is used in refrigerators.

So basically a refrigerator works by causing the refrigerant circulating inside them to change from liquid into gas. To change the refrigerant from liquid to gas, the pressure on the refrigerant is reduced through an outlet called the capillary tube. When the contents are released into the lower pressure open space, it turns from a liquid to a gas.

Now we have changed the liquid into gas but to keep a refrigerator running, we need to be able to get the gaseous refrigerant back to its liquid state. So for this purpose the gas needs to be compressed to a higher temperature and pressure again, which is done by the compressor of the refrigerator.

As we discussed above as the gas passes through the compressor, the gas is very hot and under high pressure, so it needs to be cooled down, which is done in the condenser. The condenser is located on the back of the refrigerator, so its contents can be cooled by the ambient air. When the gas cools off inside the condenser, it changes back into a liquid. And then, this liquid refrigerant circulates back to the evaporator and the whole process starts all over again.

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