Why Does a Refrigerator Need a Compressor?

A refrigerator, commonly known as a fridge, is a device that dissipates heat from inside a thermally insulated structure to keep it cool for storing food supplies, chemicals, vaccines and other temperature-sensitive products. Refrigerators are widely used in commercial and residential appliances to store a wide array of products in myriads of industries.

A refrigerator helps preserve food by preventing the growth of microorganisms that cause spoilage such as bacteria, yeast and fungi. Storing the food at low temperatures inhibits the growth of bacteria and slows down the bacterial activity responsible for spoiling food.

Refrigerators are primarily used for food preservation but they also find uses in various other industries where they deal with temperature-sensitive products like the medical or chemical industry.

A refrigerator is a combination of various smaller components that make up a large unit, however, if we were to count a few on our fingers, the four main components would be: compressor, evaporator, condenser, and expansion valve.

Compressor: A compressor serves the purpose of compressing the refrigerant into high-pressure, high-temperature gas. It is central to the mechanism of a refrigerator; it circulates the refrigerant throughout the refrigeration system. The refrigerator compressor is both a motor and a pump that moves the refrigerant inside the system . The compressor compresses the low-temperature, low-pressure refrigerant gas it receives from the evaporator. A refrigerator compressor works directly with the condenser, evaporator coil and expansion valve.

Evaporator: An evaporator absorbs heat from inside the refrigerator. The refrigerator evaporator transfers heat from the objects inside the refrigerator to the outside of it.

Condenser: A condenser in a refrigeration system acts as a cooling device. It discards the heat from the hot refrigerant gas and condenses it into liquid refrigerant.

Expansion valve: An expansion valve is responsible for dropping the pressure and temperature of the refrigerant to allow its expansion.

A refrigeration cycle, also known as a heat pump cycle, is a thermodynamic cycle, that removes heat from a specific space . There are four major processes involved in a refrigeration cycle, namely: compression, condensation, expansion and evaporation.

The refrigeration cycle starts with a compressor. Firstly, the compressor compresses the refrigerant gas to increase its pressure and temperature.

The refrigerant gas is then pushed into condenser coils, located on the back of the refrigerator.
As the high-temperature, high-pressure refrigerant gas flows into the coils, it comes in contact with the low-temperature outside air. The heat from the hot refrigerant gets dissipated to the surroundings turning it into liquid.

The expansion valve reduces the hot liquid refrigerant’s pressure and temperature before it enters the evaporator coils. Consequently, the refrigerant expands decreasing its temperature and pressure.

The low-pressure, low-temperature refrigerant then enters the evaporator coils which are usually located inside the refrigerator. As the heat from the refrigerator passes over the evaporator coils, refrigerant flowing through the coils absorbs this heat and turns into low-temperature, low-pressure refrigerant gas.

As the refrigerant absorbs heat from the air, it cools down the air inside the refrigerator, creating a cold environment for storing food and other items. The low-pressure, low-temperature refrigerant gas is again sucked into the compressor and the refrigeration cycle repeats itself. And this is how a refrigerator always keeps its contents cold and fresh.