Air Conditioner Compressor
Scroll, Screw and Piston Compressors
Air conditioner compressors are the heart of the system because they pump the refrigerant through the system in a closed cycle in much the same way as the heart pumps blood through the body’s system. The other main function of the air conditioner compressor is to compress low pressure refrigerant gas from the evaporator converting it to a hot, high pressure gas. In doing this the compressor also removes vapor from the evaporator to help it maintain a constant temperature.
Scroll air conditioner compressors are favored for their efficiency as they move refrigerant gas along in a continuous flow. This means that the system runs smoother, quieter and has less leakage than the other types. This is due mainly to its efficient design which helps it to perform its functions more effectively. It also has some built in mechanisms to help prevent damage to the compressor.
The refrigerant is then pushed along by air that is compressed between two spiral cogs that fit together in such a way that they form curved gas pockets. One of these cogs is continuously moving around the other in order to drive this air out through the exhaust. Gas is drawn into one of several pockets which become gradually smaller as the cogs continue to move round. This motion compresses the gas which becomes very hot. Once it is sufficiently compressed it is released and moved along to the condenser. Ruud manufacturers (a brand owned by Rheem) are one of the few manufacturers whose entire line of residential air conditioners utilizes this type of compressor for its efficient and quiet operation.
The screw compressor is often popular because of its simple design. It usually consists of two intermeshed, screw shaped rotors or spindles that will rotate in opposite directions. The refrigerant gas enters the enclosed chamber where it is trapped and compressed between the intermeshed spindles. The opposed rotary directions of these spindles is what causes the gas to move from entrance (suction) to the exit (discharge) where it is moved on to the condenser. This design provides quiet and continuous flow but is ultimately not as efficient as the scroll compressor.
Piston, or reciprocating air conditioner compressors, are less popular in residential cooling systems because they are noisier than the other two types. This is because they utilize pistons that are driven by a motor to compress the gas in a cylindrical-shaped chamber. The gas is taken into the chamber at one end and pistons are pushed in to reduce the amount of space inside. This then compresses the gas which is released through the other end of the chamber and on into the condenser. Aside from being noisy these are not able to supply a smooth and steady flow of refrigerant as effectively as the others are. They are used more frequently in high pressure systems rather than conventional residential air conditioners.