How to Choose the Right Refrigerator Air Dryer or Desiccant


Removing moisture from an industrial compressed air system is vital. When the compressed air is dry, tools, instruments and equipment that use the dry air work better. Additionally, the removal of moisture can improve the life of the tools you use by reducing or eliminating corrosion. Dry compressed air affects the cost of the machine you purchase because the cost of the equipment increases as the level of dryness increases. To keep your costs reasonable, therefore, you need to purchase a compressed air dryer that is of the right size. 

Refrigerated Vs. Desiccant Air Dryer Systems

Refrigerated dryer systems remove moisture from the air by cooling it. Because cold air does not hold a lot of water, the water condenses and is removed as liquid water. Desiccant air dryer systems, on the other hand, pass the air over a desiccant which absorbs the excess water, thereby removing it from the air. The desiccant used in desiccant air dryer systems has thousands of tiny pores that capture and trap water molecules. Once the desiccant becomes saturated, it is dried using compressed or heated air.

Operating Conditions

The first thing to consider when choosing a refrigerator or desiccant air dryer is the conditions inside the area of operation. Both of these systems have specific requirements depending on the size of the system used. The capacity to remove water from the air passed through these systems varies according to the system’s size in relation to operating conditions.

Air Temperature

Hotter air holds more water and so the drying capacity of the system used is affected if the air is too hot. If the air to be dried is cooler, it holds little water and so a smaller system is adequate for these conditions.

Air Pressure

When the air pressure is low, the air moves through the air dryer at a higher velocity. This means there is less contact time between the heat exchanger or desiccant bed. Higher air pressure results in a lower air velocity which increases the contact time, thereby producing better results.

Ambient Air Temperature

Refrigerated air dryers are affected more by higher ambient temperatures than their desiccant counterparts. Higher ambient temperatures result in heat dissipating less efficiently inside a refrigerated air dryer, which makes it less efficient. The reverse is true in cooler environments. To ensure maximum operating efficiency, you need to find a way to lower the ambient temperature to ensure suitable operating conditions.

Consider Corrections According to Your Conditions

Manufacturers of both refrigerated and desiccant air dryer systems provide corrections for different conditions. These correcting factors have to be applied to the dryer’s capacity to ensure it works efficiently under your operating conditions. These corrections can also be used to find out the worst conditions your system can operate under.

Talk to an Expert

When choosing a refrigerant or desiccant air dryer, you want one that will dry the air to the required level, and no more or less. While the above factors can help you choose between the different types of air dryers as well as system sizes, always consult an expert so they can help calibrate your system for your specific conditions and needs. Experts with a lot of experience in configuring air dryer systems can help ensure that you end up with the right, most economical drying solution for your needs.