Desiccant Compressed Air Dryers Explained

Desiccant dryers are used to remove moisture from compressed air. It is critical to remove moisture from compressed air because it can be corrosive on metal equipment and cause the freezing of components.

Desiccant air dryers come in many different sizes, styles, and configurations. However, they all work on the same principle: They contain desiccant material that absorbs moisture from compressed air as it passes through the unit. This moisture is then extracted from the desiccant material by heating it so that it releases its water vapor back into the atmosphere.

What is a desiccant dryer for an air compressor?

Desiccant dryers dry moisture from air compressors by passing the input air through a bed of desiccant material, usually, silica gel, which adsorbs the water vapor from your compressed air. This can be done by gravity alone or by using a compressor. Desiccant dryers that use a compressor are called “compressed gas desiccant dryers” or CGD units.

Desiccant is a substance that attracts and retains water molecules from its surroundings through sorption or absorption. It does this by attracting moisture molecules with forces like Van der Waals forces and hydrogen bonds which are weak enough to break when temperatures rise back above room temperature after cooling down again.

These dryers are used in many industries, including aerospace, automotive, food processing, and electronic manufacturing. The following are some examples of typical applications for desiccant compressed air dryers:


Desiccant air dryers are commonly used in the production of vehicles to remove moisture from the air before painting or coating. Desiccant air dryers are also used after painting to ensure that there is no residual moisture in the system before test driving begins.

Food Processing

In food processing plants, desiccant air dryers help keep product temperatures stable by removing excess heat from the environment around them. This helps prevent spoilage and maintain quality standards throughout a product’s shelf life.


Desiccant air dryers are used to protect sensitive components from moisture damage during the application of paint or coatings. They are also used to dry out internal components before reinstallation into both electronic and aircraft engines.

How does a desiccant compressed air dryer work?

An internal filter is installed between the dryer’s inlet and an air outlet. The filter is designed to remove dust, dirt, and rust particles from the incoming compressed air stream. The desiccant wheel is located inside the dryer housing and is used to remove moisture from the compressed air stream. 

It does this by absorbing moisture from the compressed air as it passes through the media bed of desiccant beads. The saturated bead material then releases its moisture into a liquid reservoir tank inside the dryer housing. This liquid then evaporates into vapor form, which is exhausted through an exhaust port on top of the dryer housing.

The desiccant wheel rotates in an enclosed chamber with a very high-temperature differential between its surface and ambient temperature. As the wheel turns, it draws in moist air through an opening in its front side called an intake port. 

This intake port is positioned above a large reservoir tank containing a high boiling point liquid (e.g mineral oil). When this moist air enters the chamber, it comes into contact with extremely hot surfaces on both sides of the wheel’s interior wall. This heat causes the moisture to evaporate and be released back into the atmosphere through vents at each end of the wheel’s exterior wall. 

If not properly controlled, this moisture may damage sensitive equipment or cause corrosion to metal components within a compressed air system.

The energy required to operate a desiccant wheel dryer is minimal compared to other types of moisture removal systems such as refrigeration or liquid nitrogen systems. This means that they are very efficient at removing moisture from air streams at low temperatures.

The most common type of desiccant used in these systems is silica gel because it is highly effective at removing moisture from the air while being non-toxic and chemically inert against most substances found in industrial environments.

How Do You Size a Desiccant Air Dryer?

The most common way of sizing a desiccant air dryer is to determine the moisture content of the incoming airstream and then select a desiccant air dryer with the appropriate capacity. This approach works well for most applications. 

An easy method can be used to select the correct size for a desiccant air dryer:

This method involves calculating the amount of water in the incoming airstream based on temperature and pressure measurements (see below). 

For this calculation, you need to know two things: 

  • how much water will condense out when your dew point is reached 
  • what relative humidity your dew point corresponds to (which is usually expressed as a percentage). 

The amount of water that will condense out when your dew point is reached is the key to this calculation.

The way this works is that you know your dew point, which is the temperature at which air can hold no more water vapor. The temperature of your compressed air will rise until it reaches the dew point; after that, all of the moisture in the air will start to condense out onto surfaces. 

By knowing your dew point and how much moisture you want to leave in your compressed air, you can calculate how much moisture will be left in the air once it reaches its dew point.

The amount of water that will condense out depends on the relative humidity of the air at your dew point. For example, if your dew point is 55°F and the RH is 80%, then about 0.5% of your total volume of compressed air will be made up of water vapor.

If you have a compressor that operates at 20 cubic feet per minute (cfm) and a dew point of 55°F, then you will have about 0.5% water vapor in your compressed air system if it operates at 80% RH. A 1-horsepower motor driving this compressor would consume about 11 amps at 115 volts.

How Much Do desiccant air dryers cost

The Average cost of a desiccant air dryer is $3500. The cheapest desiccant air dryer is $1,000, while the most expensive desiccant air dryer costs $100,0000.

Desiccant air dryers are typically more expensive than other types of air dryers. This is because they provide a higher level of efficiency, as well as better quality control. The price will also vary depending on your location and the manufacturer that you choose.

Pricing depends on several factors, including:

Type of desiccant wheel – Regenerative desiccant wheels are more expensive than other types of desiccants such as silica gel or molecular sieve.

Size – Larger units cost more per square foot of drying area than smaller ones do.

Output – A unit with higher output will cost more.

For example, if you were looking to buy one of these units then you would expect to pay anywhere between $1,000 and $12,000. If you wanted an 80-pound unit for example, then you would be looking at paying anywhere between $10,000 and $15,000. There are air dryers that can even cost up to $100,000!

Desiccant beads: What are they and how do they work?

Desiccant beads are small desiccants that are used to dry out the air. When you use the desiccant bead, you should place it in a container or bag, and then put it in the area where you want to remove moisture. 

The desiccant bead will absorb moisture from the air, which is why they are often used in places like boats and cars that have been exposed to humidity.

Desiccant beads

The benefits of using desiccant beads 

They can last for a long time without needing to be replaced or refilled with water. They can also be used in a wide variety of applications because they don’t require any special equipment or maintenance on your part other than keeping them dry when not in use so that they don’t deteriorate over time.

The material of desiccant beads 

Desiccant beads are made of silica gel or zeolite, both of which have a high affinity for water molecules. When the beads come in contact with moisture, they absorb it until they reach their saturation point, at which point they can no longer hold any more water.

The beads then need to be regenerated by heating them above their melting point for them to release the absorbed water back into the air.


A desiccant dryer will greatly boost the efficiency of an air compressor. This will save you a lot of money because you won’t need to purchase as much new gas to run the compressor. You will also have to clean your machinery less frequently, and won’t have to worry so much about rust, or a reduction in longevity caused by moisture in the compressed air.

They are extremely efficient, with a high dew point and very little water vapor being added to the air as it’s dried. They do operate more quickly under certain conditions, which means you’ll need to monitor the system and make sure it isn’t overheating. 

With an extra safety precaution in place, these dryers are an excellent way to ensure that your compressed air comes through as dry as possible, free of any excess moisture!

      Residential & Commercial Air Compressors