Refrigerated air dryers are one of the most common types used in industrial applications due to their ease of maintenance and relative cost-effectiveness. They are suitable for air-drying applications without special requirements such as a minimum dew point.

The refrigerated air dryer working principle is based on de-humidifying air by rapidly cooling it, condensing it, and draining off the moisture. The operation is like that of a domestic refrigerator or home air-conditioning system.

Refrigerated air dryers de-humidify air through the following phases:

• Warm, moist air enters the dryer, which cools it rapidly to about 3°C (37.4°F) in a refrigeration unit. At this temperature, the water vapor in the air condenses into pure water, which collects in a water trap and fed into discharge lines. The warm, gaseous refrigerant is cooled and regenerated in a condenser.
• The dry air in the chamber is re-heated to room temperature and fed through an outlet.

Moreover, refrigerated air dryers are available in two variants – cycling and non-cycling.

• Cycling dryers are 100% duty cycle machines that can maintain the dew point at a constant temperature.
• Non-cycling dryers work by intermittently shutting down and restarting to maintain the required temperature.

Both variants are useful in different applications, although cycling types tend to ramp up maintenance costs.