Both reciprocating (piston-style) and rotary screw air compressors can deliver a reliable supply of compressed air, but there are important differences.
Oil-flooded rotary screw air compressors are the most commonly used type of air compressor for industrial applications. Compared to piston-style air compressors, they are quieter, more energy efficient and deliver a higher CFM per horsepower. They also operate at lower temperatures and produce cleaner air with less oil carryover. Most importantly, a rotary screw air compressor operates at a 100% duty cycle. That means they can produce air continuously for operations requiring a constant supply of air 24/7. A rotary screw air compressor can last a long time, too–up to 60,000 to 80,000 hours of use before requiring a rebuild. While they are more expensive up front, they have lower life cycle costs when you factor in their longer lifespan and lower energy use.
Piston-style air compressors cost less up front and are simpler to maintain. They are also less finicky about the operating environment, performing well even in very dirty environments. Reciprocating air compressors are not designed for continuous use; they typically have a duty cycle between 30%-70%, meaning they are only making air for 30%-70% of the time.
The biggest consideration in deciding between a rotary screw and reciprocating air compressor is how you are using your air. Rotary screw air compressors are designed for continuous use and do not perform well if air use is intermittent. If your air demand is variable but does not drop to zero while the compressor is powered on, a variable speed drive (VSD) motor will allow the compressor to ramp HP up or down in response to demand. Rotary screw compressors (or their cousins, rotary vane air compressors) are an excellent choice for robotic manufacturing, pneumatic conveyor systems, and other applications requiring constant air. If your applications are highly intermittent–e.g., blow off, occasional manual tool use, stop-and-start applications–a piston-style compressor may be the better choice.
Read our complete guide to rotary screw air compressors and contact us for help with compressed air equipment selection.