Air Conditioning Compressor Types And How They Work

An air conditioner runs on a complex system that is only explainable in technical terms. However, the main thing you should learn about the system is the compressor because it is the AC’s engine. 

Air conditioning compressors have evolved to meet specific cooling requirements. As a result, some are high maintenance than others, and you must take time to understand how they work before considering them. 

Let us understand how AC compressors work and how their construction impacts functionality.

What is an AC Compressor?

An AC compressor in an air conditioning system operates like a car engine. It runs the AC by changing the refrigerant from a cool, low-pressure liquid to a highly pressurized hot gas. The temperature change facilitates other AC components to create cool air, which cools rooms when it is hot.

How Does an AC Compressor Work?

An AC compressor has a refrigerant that enables air conditioning. This magic fluid can change its nature repeatedly, from a low-pressure liquid to a high-pressure gas. At its low-pressure state, the refrigerant cools and causes evaporation when it combines with warm air. At higher pressures, the refrigerant becomes hot and condenses when exposed to cool air. The condensation process heats the air to raise the temperatures.

The AC compressor compresses the refrigerant vapor to increase the pressure and convert it into a hot gas. The condensation and cooling of the hot gas occur when a fan draws the ambient air through the condensing coil and leaves it as hot air. The refrigerant further cools and turns into a liquid where the compressor pushes it indoors into the evaporator.

It passes through a restrictor that lowers the refrigerant’s pressure to cause evaporation and cool the air as it moves towards the evaporator. Then, the air is pumped back outside to the compressor to restart the cycle. There are different types of AC compressors with different working mechanisms.

TYPES OF AC COMPRESSORS

Reciprocating Compressor

A reciprocating AC compressor has a piston and cylinder that compresses the refrigerant. It operates by sucking the refrigerant into the cylinder using the vacuum created by the piston’s downward movement. Then, the piston moves up to compress the gas, pushing it into the condenser.

Scroll Compressor

Scroll compressors have one fixed spiral-shaped scroll and an orbiting/moving scroll. The fixed scroll stays stationary while the orbiting scroll rotates using the swing link. As the orbiting scroll moves, it pockets the refrigerant between the two scrolls, compressing it by slowly pushing the scrolls to the center.

Screw Compressor

The screw AC compressor has two helical rotors rotating and moving air from the compressor intake towards the screw endings. The air movement from one end to the other tightens the space, further compressing the refrigerant.

Rotary Compressor

A rotary compressor has a smaller and quiet design, built with one or more blades attaching to the cylinder shaft. The refrigerant intake is placed at the point with more space between the shaft and cylinder wall. The outtake is placed where the smallest space between the shaft and cylinder wall is. Rotation of the shaft vanes moves the refrigerant towards the smallest space to compress it.

Centrifugal Compressor

Centrifugal compressors have fewer moving parts. The centrifugal force from the motor mounting sucks the refrigerant into the impeller, spinning faster within the housing compartment. Once the refrigerant gains velocity in the system, it compresses upon reaching the terminal velocity on the external edge of the impeller.

Hermetic Motors in Compressors

A hermetic motor in an AC compressor operates like any other unit. Only the system structure and compartmentalization are different. This motor mounting is entirely sealed to make it airtight. In addition, the compressor and motor are enclosed within a steel casing, connecting to one shaft. 

Hermetic motors also do not have belts that need constant lubrication. You can therefore use them consecutively for months without opening them.

Hermetic AC compressor motors perform better than the rest because they are leak-proof. They are also long-lasting and will rarely run into mechanical issues. Considering that they can last more than five years, most manufacturers offer extended warranties to cover maintenance and repair. 

Overall, Hermetic motors work better than traditional compressors and if you have a few bucks to spare, consider them for your AC applications.