Refrigerant air dryers are commonly used types of compressed air dryers because they do not require much maintenance, are relatively cheap and are easy to operate. If you don’t have any special requirements for your application (such as extremely low dew points), they’ll work quite well. You can install it and then likely never have to think about it again.
The system works by cooling down the air to approximately three degrees Celsius. At that point, all the water vapor condenses into water. That liquid water can then be removed from the system through a simple water trap, after which point the cold air gets reheated to room temperature. Because most of the water has been condensed and removed from the system, the reheated air is significantly dryer than it was before. The cooling process works similarly to the process used in a refrigerator or freezer. Liquid refrigerant gets evaporated in a separate circuit, and is used to cool down the compressed air. As the air cools, the refrigerant gets warmer. The refrigerant goes into a small compressor of its own, then gets re-cooled in a condenser, and the process continues to cycle over and over as the air compressor brings in more air.
A refrigerant air dryer is a specific type of compressed air dryer that is used to remove moisture from compressed air, which always contains water. Refrigerated or refrigerant drying means that the compressed air is cooled, which allows a large amount of the water to condense and be separated. After cooling and condensing, the compressed air is reheated to around room temperature so that condensation does not form on the outside of the pipe system. This heat exchange between ingoing and outgoing compressed air also reduces the temperature of the incoming compressed air, and as such reduces the required cooling capacity of the refrigerant circuit. Cooling the compressed air takes place via a closed refrigerated system. Smart steering of the refrigerant compressed air dryer via intelligent control algorithms can significantly reduce the power consumption of modern refrigerated dryers. Refrigerated dryers are used for dew points between +2˚C to +10˚C and have a lower limit, which is the freezing point of the condensed water. They are available as either a freestanding machine or an integrated drying module inside the compressor. The latter has the advantage of having a small footprint and ensures optimized performance for the particular air compressor capacity. Modern refrigerated dryers use refrigerant gases with a low Global Warming Potential (GWP), which means refrigerant gases that -when accidentally released into the atmosphere- contribute less to global warming. Future refrigerants will have an even lower GWP value, as dictated by environmental legislation.
