Refrigeration Air Dryers

Refrigerated compressed air dryer

Get a low-cost way to remove water from compressed air, by installing a refrigerated compressed air dryer and avoid condensate problems.

A refrigerated compressed air dryer is a type of compressed air dryer, used to dry compressed air. Compressed air always contains water, coming from the air that is sucked in by the compressor.

To protect your piping, tools and equipment, it's best to use a compressed air dryer to dry the air.
Why a refrigerated compressed air dryer?

refrigerated air dryer

Refrigerated compressed air dryers are one of the most common used types of air dryers (for other types, check out our general page on compressed air dryers). They are simple in design, need very little maintenance and are relatively cheap.

A refrigerated compressed air dryer is the standard choice if you're shopping for a dryer and don't have special requirements, like an ultra-low dewpoint. They don't need much or any special maintenance and
if you buy a quality one, and install it properly, it's basically set-and-forget.
How does it work?

As the name implies, a refrigerated air dryer works by cooling down the air (like a refrigerator). The warm wet air enters the dryer, where it is cooled down to about 3 degrees Celsius. All water vapor that was in the air condenses into water. Much like your window does on a cold day. The liquid water is then removed from the compressed air by a water-trap.

After that, the cold air is re-heated to room temperature. Since a lot of water has condensed into water, the air is now much dryer.

The cooling is done in the same way as your freezer and fridge are cooled. In a separate circuit, liquid refrigerant is evaporated in the evaporator, to cool down the warm compressed air. The air is cooled,
while the refrigerant gets warmer. The refrigerant is compressed by a small compressor and cooled again
in the condenser.

Here are two pictures of the inside of an old refrigerated compressed air dryer. You can see the various parts of the refrigerant circuit (with refrigerant compressor and condensor). You can also see the condensate trap with discharge lines.

The evaporator (where the refrigerant cooles down the compressed air) is located at the top of the dryer (the whole area at the top is the insulated evaporator.

inside-old-refrigerated-compressed-air-dryer2

In the background you see the refrigerant circuit of a compressed air dryer. In the middle is the condensate trap (with water discharge lines).

inside-old-refrigerated-compressed-air-dryer1

At the right the condensor with cooling fan. In the middle you see the refrigerant pipes that go to the evaporator. At the left the condensate trap again.
Types of refrigerated compressed air dryers

There are basically two types of refrigerated compressed air dryers. Cycling and non-cycling. The advantage of the cycling dryer is that it will increase or decrease cooling capacity according to air use. This reduces the energy used and saves you money.

The non-cycling is the most common type and is extremely reliable and have the lowest maintenance
costs.