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CHILLER DESIGNS

        Next we can learn about a few different styles of compressors. We will focus mainly on the designs used by Chiller Manufacturing.

Chiller uses Scroll and Piston style compressors.

A "SCROLL" style compressor is just as it sounds. Two scrolls rotate about a shaft to create a pump. The scroll design is typically more tolerant to the liquid slugging we discussed earlier. The reason for the greater tolerance to liquid slugging is the scrolls are not "fixed" to the shaft to maintain a specified orbit. If the scrolls encounter an incompressible amount of liquid refrigerant, they simply separate far enough to allow the liquid to pass through. A piston design is not as forgiving. The piston would strike the liquid refrigerant and try to compress it to the end of the piston's stroke. If enough liquid exists in the cylinder, the piston shaft would more than likely break.

The scroll compressor is typically somewhat more efficient than the piston design, but both are very valuable and reliable compressors for the refrigeration industry.

The "PISTON" style compressor works like a car engine. A motor rotates a shaft that is curved like a crankshaft in a car. On this shaft resides one or more piston rods which are connected to the pistons. The pistons move up and down in their own cylinder creating pressure. The pressure is released by an exhaust valve which allows the compressed, hot refrigerant gas escape to the condenser. On the return to the compressor, a suction valve opens on a down stroke of the piston to draw in the cooler, low pressure suction gas. Unlike the piston style compressor, the scroll compressor has no valves. The orbiting scrolls do the job of the piston and the valves.