The compressor duty cycle refers to the percentage of time a compressor can safely run without risking overheating or excessive wear and tear. It is typically expressed as a ratio or percentage. For instance, a compressor with a 50% duty cycle is designed to run half the time and rest half the time. Understanding the duty cycle is crucial in selecting the right compressor for your application. The reason? Exceeding the recommended duty cycle can lead to overheating, excessive wear, and even premature failure.
Reciprocating compressors rely on radiant cooling and don't have a cooling circuit to remove the heat of compression. As a result, they have a low-duty cycle, needing time to cool off. Heavy use or a high-duty cycle is not recommended. They work best with intermittent or partial duty—50% duty cycle or less. That’s 30 minutes in an hour. Run it longer, and you risk damaging your compressor and shortening its life. As a result of this shortened duty cycle, you need to add storage tanks to ensure that compressed air is available during their “cooling-off” period.
Rotary screw compressors can handle a 100% duty cycle. In fact, we recommend setting up your compressed air system so that they operate as close to 100% duty cycle as possible. In addition, rotary screw compressors are very good at handling variations in demand. Although screw compressors do not need storage tanks to provide continuous coverage, they do need tanks for control storage, which covers the time it takes controls to go from unload to load.