How does a refrigerator compressor work?

The compressor of a refrigerator is a vital component of the appliance. It compresses the air while controlling the flow of the refrigerant. The main job of a compressor is to convert the low gas to a high-pressure one and maintain the flow of cool air inside the refrigerator. To know more about refrigerator compressors, keep on reading till the end.

Types of Compressor

There are different types of compressors available in the market. Some of the most popular ones are:

Reciprocating compressors: Brands usually prefer to use reciprocating compressors in commercial refrigerators. They come with a cylinder and a piston exactly like motor vehicles. The piston of the compressor works in reciprocating motion within the cylinder. Hence, it is called a reciprocating compressor. When the area is sealed and no air can pass, then it is called a hermetic compressor.

Screw compressors: Another famous type is the screw compressor which is circular and produces tremendous pressure. In this type of compressor, the quantity of the gas is quite low and the pressure is comparatively much higher. The screw compressor has a pair of meshing screws that compresses the refrigerant. Industrial refrigerators and refrigerators used in factories are made with screw compressors.

Scroll compressor: Scroll compressors consist of a pair of interwoven scrolls that create pressure. One is a fixed scroll and the other is a moving one. When the moving scroll orbits around the fixed one, it creates a gap. This is how the compression is created in a scroll compressor. As one of the scrolls is fixed, it saves the cost of energy. They are great for commercial places.

How does the compressor work?

The compressor of a refrigerator works as a motor and also as a pump. The basic job is to circulate the refrigerant within the system. The compressor starts when it receives a signal from the temperature sensor. When the internal temperature of the refrigerator increases to a certain point, the compressor automatically turns on. Usually, when we open the door of a refrigerator, warm air gets in and rises the inside temperature.

There is no refrigerator that is entirely sealed.

At the very beginning, the compressor pulls in the solid refrigerant and turns it into liquid. The refrigerant gas turns into liquid once the temperature reaches -26.6 degrees Celsius. Once the refrigerant becomes liquid, the compressor generates enough pressure to increase the temperature. Then the warm compressed gas is pushed towards the outer metal tube which is usually situated in the back of the refrigerator. Some refrigerators have metal tubes on the bottom. With the help of these tubes, the warm air evaporates. Once the pressure is released, the gas transforms into liquid once again.

After that, the liquid form transports within the system till it finds the expansion valve. These valves push the liquid to a tiny circular area. As the pressure rises, the liquid gas turns into a cold haze. The haze also evaporates like the warm air once it passes the metal tube or coils of the freezer. Usually, the temperature is around -33 degrees Celsius at this stage.

Once the cooler form of the liquid gas passes the metal tube, it sucks out the heat from the freezer and the other compartments of the freezer. The entire concept is known as thermodynamics 2nd law. The heat transfers from a relatively warmer entity to a colder entity. Here, air will be the warmer entity and evaporating gas will be the colder entity.

The metal tube is headed towards the compressor. Once the liquid gas hits the compressor, it starts to put pressure on the gas. The warmer gas is then pushed towards the coil by the compressor in order to evaporate the heat. This goes on until the temperature of the refrigerator reaches the optimum level. When the refrigerator reaches its perfect temperature, the sensors send a signal to stop the compressor.

Because of this technique, a lot of people believe that a fridge doesn’t keep the food cold rather it circulates cold air. Hence, experts say that if the compressor needs very minimum energy to keep the refrigerator working, it will lower your electricity bill to a significant amount.

A compressor is often compared to a heart. Just like our arteries pump the blood through our veins to our entire body, the compressor of a refrigerator pumps the gas through its tube. Here, the blood can be compared to the refrigerant and the body can be compared to the unit of the refrigerator. The main purpose of a compressor is to maintain the temperature of the refrigerator. Hence, when coils become dirty, compressors cannot maintain the temperature properly. The compressor needs more energy than usual to do its job which increases the electricity bill. So, if you ever see a sudden rise in your electricity bill, maybe you need to take a look at your compressor.

Along with a compressor, a refrigerator has other units too which help the compressor to do its job properly. Here’s how a refrigerator function:

Stage 1- Evaporator: The compressor pushes the liquid refrigerant forward. When it touches the evaporator, it sucks in the warmer air within the refrigerator. The liquid refrigerant helps to soak up the warm air.

Stage 2- Compressor: The compressor creates pressure on the liquid refrigerant which helps to create the vapor. Then the electric motor decreases the temperature of the refrigerator. Most of the commercial refrigerators have reciprocating compressors which have a piston and a cylinder. Some of them also use a screw compressor which is known for its coil.

Stage 3- Condenser: From the compressor, the pressurized gas goes to the condenser. Here the transfer of heat happens. The refrigerant releases its heat and turns it into liquid from vapor.

Stage 4- Expansion valve: After that, the liquid refrigerant directly enters the expansion tube. The condenser does it by pushing the liquid towards the evaporator. Once again, a significant amount of refrigerant evaporates. Then the cold air goes into the evaporator for further heat reduction.

These four stages continuously occur until the refrigerator reaches a certain temperature. So if your refrigerator is not cooling properly, make sure that you check the compressor.

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