Refrigerated air dryers are the work horses of the air treatment industry, likely accounting for more than 85% of all installations.  So how do they work?

First you need to consider a basic physical principle.  When humid air cools, water condenses.  Think of a hot summer evening in the Deep South.  The air is almost intolerably humid.  You take a cold can of Coke from the refrigerator and place it outdoors on a picnic table.  What happens on the surface of that can?

Beads of water form on the can.  Of course!

The cold surface of that can has chilled the surrounding air.  Voila, condensation.

The same thing happens within a refrigerated air dryer.  When compressed air leaves the air compressor it is hot and humid.  The refrigerated air dryer chills the compressed air and collects the droplets of condensed liquid.

After these water droplets are removed, the dryer reheats the compressed air.  Why is this important?  Two reasons.

First, it makes the dryer more energy efficient.  The energy for reheating comes from the hot incoming air.  This reduces the load on the refrigeration system.

Two, think about what would happen if the air leaving the dryer were too cold.  The pipes in your air system would also become cold and possibly start sweating.  Again, think of that cold can of Coke sitting outside.  You’d have condensation dripping from pipes all over your shop!

Have questions?  I love helping customers solve moisture problems in compressed air systems.  Send me an email.

And, as a thank you for visiting Moistureboss.com, use the coupon code “THANKS” to get $25 off the purchase of any refrigerated air dryer sold here.

Check out the animation below showing how compressed air and refrigerant flow through a PRD Series dryer from Parker.