Published: 19/11/2025
Types of Compressor Air Dryers: Refrigerant vs desiccant vs membrane
Air dryers are used to remove water vapour from compressed air. They ensure clean, dry air as a product of your compressed air system.
There are several types of air compressor dryers, including:
- Refrigerant air dryer
- Desiccant air dryer
- Membrane air dryer
Want to know the answer to ‘how do compressed air dryers work’?
Read on to find out how each of these compressor dryers works and why they are used for certain applications.
Looking to buy an air dryer? Talk to our experts to hear your options.
How does a refrigerated air dryer work?
The clue is in the name, as this type of air dryer uses cooling methods. Compressed air is cooled to the dew point, which is a low temperature of around 3 °C. The moisture in the compressed air condenses at this temperature, so it can be drained away. Before the air is used, it is reheated to room temperature.
Refrigerating air dryers are the most commonly used. They work well for a wide range of applications and remove moisture from compressed air efficiently and simply. They are a solid choice for standard applications.
However, if you require 100% pure and clean air, refrigerant air dryers are not suitable because they don’t achieve completely moisture-free air.
What is a desiccant dryer for an air compressor?
Desiccant dryers use the adsorption dryer working principle. You may hear them being called adsorption dryers, but this is because of how they function.
Desiccant dryers are often used as a second-stage dryer, after a first stage using a refrigerating dryer, for example. They use a desiccant material, such as alumina or silica gel, which dries and filters the air from moisture. This porous hygroscopic medium has natural moisture-absorbing properties, which is why it works so well within air dryers.
Most adsorption air dryers have two desiccant chambers. One will dry out compressed air while in the other chamber, also filled with desiccant, the desiccant is being regenerated. This makes for efficient, easy-to-maintain production of dry compressed air.
This type of compressor dryer is ideal for applications needing very dry air. They can reach very low dew points, meaning they are useful for applications with sensitive or extreme environments.
Membrane air dryers and how they work
Membrane compressed air dryers work differently in the sense that they are a filtration system. The compressed air passes through a bunch of semi-permeable membrane fibres. Because this membrane only allows moisture to pass through, the moisture from the compressed air diffuses, or escapes, through the fibre walls. The air continues to travel through the walls to the outlet.
This type of dryer is great for smaller projects and point-of-use applications. The gases are actually separated, so membrane dryers are good for industries like food production.
Do I need an air dryer for my compressor?
It can be difficult to determine which type of equipment you need to add to your compressed air system.
That’s why the Air Supply team are here to help. Our experts with over 30 years’ experience can listen to your requirements and advise on what’s best for your circumstance.
Fill out our contact form or give us a ring on +44(0)161 5183440 to get in touch with our team.