There are two general classes of refrigerated air dryers, non-cycling and cycling.

In a non-cycling dryer, the refrigerant compressor runs continuously, regardless of the actual compressed air flow rate or moisture content of the air.  A hot gas by-pass valve regulates the flow of refrigerant to accommodate variable conditions but this does not reduce the energy consumption of the refrigerant compressor.

Cycling air dryers are often described as energy management dryers because their energy consumption fluctuates according to flow rate and moisture load in the compressed air system.  Most cycling designs use a thermal mass to store refrigeration capacity in low load conditions.  When the that mass has been chilled to its low point, the refrigeration compressor can shut down.  The novel cycling dryer design from the manufacturer MTA (pictured below) uses a microprocessor controlled modulating valve on the suction side of the refrigeration compressor.  During low flow conditions, this valve “chokes” the flow of refrigerant to the compressor.  In turn, the refrigerant compressor uses less energy by not compressing unneeded refrigerant.

Advantages of Non-Cycling Air Dryers

• Lower initial cost
• Consistent dew point

Disadvantages of Non-Cycling Air Dryers

• No energy savings during partial flow and low moisture conditions

Advantages of Cycling Air Dryers

• Reduced energy cost in most air system

Disadvantages of Cycling Air Dryers

• High initial cost
• Dew point fluctuations
• More weight to accommodate the thermal mass (some designs)
• Shorter compressor life due to start-stop operation

Which type of dryer is right for your facility?  That depends on a few variables, including electricity cost, air system duty cycle, and dew point requirements.

Need a quote on a dryer, filter, or replacement elements?  Call or email for support with your application.  tyler@Moistureboss.com