Types of Refrigeration Compressors

What is Compressor?

If HVAC Chiller is the heart of building's refrigeration system then compressor is the heart of a chiller or AC or VRF system. It is Pump of a refrigeration system which draws a low pressure on the cooling side of a refrigerant cycle and squeezes or compresses the gas into the high pressure or condensing side of the cycle.

While all AC compressors have the same job, they work in varying ways and offer different pros and cons. here we will take a look at 5 types on compressors used in air conditioning and refrigeration.

Reciprocating Air Compressor

The term Reciprocating refers to the back-and-forth movement of the compression device (a piston or other device is positioned in a cylinder). Reciprocating compressors use the inward stroke of a piston to draw (intake) gas into a chamber and then use an outward stroke to positively displace (discharge) the gas. A common application for the reciprocating compressor is in an instrument air system.

This is the most commonly used type and is very versatile. It uses a piston and cylinder design to compress the refrigerant. Powered by a motor and crankshaft, the piston moves up and down inside the cylinder. The refrigerant is sucked into the cylinder by a vacuum that is created as the piston moves down. When the piston moves back up, it compresses the gas, which is then pushed into the condenser. Reciprocating compressors are very efficient and you can get AC units that have 2, 4, or even 8 cylinders in its compressor.

Scroll Air Compressor

Scroll air conditioning compressors, are newer on the scene. They contain one fixed coil-called the scroll-in the center of the unit, and then there is another coil that rotates around it. During this process, the second scroll pushes the refrigerant towards the center and compresses it. Scroll compressors are quickly becoming as popular as reciprocating compressors because they do not have as many moving parts and are therefore more reliable.

The advantage of scroll compressor is that it has fewer moving parts and less torque variation compared to the reciprocating compressor. This advantage is translated to a smooth and quiet operation. The scroll compressor is also known as scroll pump or scroll vacuum pump.

Screw Air Compressor

The screw compressor is extremely reliable and efficient, but it is mainly used in large buildings where there is a vast amount of air that requires continuous cooling. A screw air conditioning compressor contains two large helical rotors that move the air from one end to the other. As the refrigerant moves through the compressor, the space gets smaller, and it gets compressed.

Rotary Air Compressor

Rotary are small and quiet, so they are popular in locations where noise is a concern. The inside of this type of AC compressor contains a shaft with several blades attached to it. The bladed shaft rotates inside the graduated cylinder, consequently pushing the refrigerant through the cylinder and compressing it simultaneously. 

Centrifugal Air Compressor

The final type of AC compressor is the centrifugal compressor. As the name implies, it uses centrifugal force to pull in the refrigerant gas and then spins it rapidly with an impeller to compress it. Centrifugal air conditioning compressors are usually reserved for extra-large HVAC systems.

Now that you know the different types of air conditioning compressors, you can choose the one that you think will serve your needs the best in terms of reliability and efficiency.