Air Dryers

What is an Air Dryer?

An air dryer is a crucial component in a compressed air system, designed to remove moisture from compressed air to ensure that the air delivered is clean and dry. This is important for maintaining the efficiency and longevity of equipment, preventing corrosion, and avoiding blockages.

Types of Air Dryers

Refrigerated Air Dryers:

Refrigerate air dryers cool compressed air in order to cause moisture to condense into liquid water, which is then easily separated from the air and drained. The dry air is then reheated before leaving the dryer.

These types of dryers tend to be more cost effective, and are ideal for general industrial use where small amounts of moisture and a dew point that isn't extremely low is acceptable.

For applications with fluctuating air demand that would be best suited for a refrigerated air dryer, we suggest a cycling refrigerated air dryer. These types of dryers will adjust their operation based on air consumption in order to reduce energy consumption.

Desiccant Air Dryers:

Desiccant air dryers leverage materials such as silica gel or activated alumina to adsorb moisture from the compressed air. This removes virtually all of the moisture from the compressed air, with the catch that the desiccant must be periodically replaced or regenerated - usually by heating it, or by using a stream of dry air.

These types of dryers are suited for scenarios such as electronics, pharmaceutical manufacturing, or instrument air generation, where exceptionally low dew points are required.

Because of desiccant air dryers' extremely high-performance, we use them on our Aurora Off-Grid Instrument Air System (pictured above).

What is Pressure Dew Point (PDP)?

The pressure dew point is the temperature at which water vapor in the compressed air begins to condense at a given pressure. It indicates how dry the compressed air is, with a lower dew point meaning drier air.

Pressure Dew Point Ranges*

Refrigerated Air Dryers at 100 PSI: 33°F to 39°F (1°C to 4°C)

Desiccant Air Dryers at 100PSI: -40°F to -100°F (-40°C to -73°C)

_{*Use this as a rough estimate, individual air dryers PDP's will vary from model to model.}

When to Use an Aftercooler vs. an Air Dryer

While aftercoolers and air dryers are by no means mutually exclusive, and are often installed alongside each other, some applications that don't require extremely low dew points may be able to get away with only an aftercooler.

If you are operating a compressed air system with PDP requirements above 4°C, getting in touch with a trained technician may be worthwhile to evaluate whether or not an air dryer is imperative.