Refrigeration is one method of removing moisture from compressed air. The dehydrator

Figure 14-23.-Refrigeration dehydrator.

in figure 14-23 is a REFRIGERATED AIR DRYER or REFRIGERATION DEHYDRATOR. This unit removes water vapor entrained in the stream of compressed air by causing the water to condense into a liquid that is heavier than air. Air flowing from the separator/holding tank first passes through the air-to-air heat exchanger, where some of the heat of compression is removed from the airstream. The air then moves through the evaporator section of the dehydrator, where the air is chilled by circulating refrigerant. In this unit, the airstream is cooled to a temperature that is below the dew point. This will cause the water vapor in the air to condense so it can be removed by the condensate drain system. After leaving the evaporator section, the dehydrated air moves upward through the cold air side of the air-to- air heat exchanger. In the air-to-air heat exchanger, the dehydrated air is raised in temperature by the warm air entering the dehydra-tor. The heating of the air serves to reduce thermal shock as the air enters the system. The exiting dry air flows into the receiver for availability to the ships air system.