Increase Air Compressor Efficiency with Compressor Controls

Most compressor systems do not operate at full-load 24-7. So, using part-load performance is critical. The method you choose to use for partial load depends on compressor type and control strategy.

But how do you choose the right compressor control method? A compressor system with a steady demand may only require a simple compressor control system. However, a more complex compressor system with multiple compressors, varying demand, and many types of end-uses will need a more sophisticated control strategy.

In any case, compressor controls can be the most important part of creating high performance and compressor efficiency. As a result, selecting your controls correctly is important for energy savings. Below, we have the different types of controls available to you.

Types of Compressor Controls

Start/Stop

Turns the motor driving the air compressor on or off in response to a pressure signal. Best used in reciprocating and rotary screw compressors.

Load/Unload

Allows the motor to run continuously but unloads the compressor when a specific pressure limit is reached. The air compressor reloads at a predetermined lower discharge pressure. In addition, this type of air compressor control is also known as constant speed or constant run control. Use this control system in reciprocating, centrifugal, and rotary screw compressors.

Modulating

Restricts inlet air to the compressor to progressively reduce air compressor output to a specified minimum, at which point the compressor is unloaded. Also known as throttling or capacity control. Most often used in centrifugal and rotary screw compressors.

Dual/Auto Dual

For small reciprocating compressors, allows the selection of either start/stop or load/unload. Dual/auto dual provides modulation for lubricant-injected rotary screw compressors to a pre-set reduced capacity followed by unloading with the addition of an overrun timer to stop the air compressor after running unloaded for a pre-set time.

Variable Displacement

Allows progressive reduction of the air compressor displacement without reducing the inlet pressure. Common in reciprocating (multi-step) and rotary screw compressors (turn, spiral, or poppet valves).

Variable Speed Drives

Finally, variable speed drives adjust the air compressor capacity by varying the speed of the electric motor driving the compressor in response to system signals.  

What Compressor Control Should I Use?

The type of compressor control your company should use largely depends on facility demand and the type of compressor you currently use. For help identifying the control that best aligns with your system, contact us by email or phone.