Refrigerant Compressed Air Dryer
Sub-Zero Refrigeration Dryers
Revolutionary Regenerative Refrigerated Dryers
The revolutionary CMT dryer is the only regenerative refrigerant dryer available in the compressed air market today. It combines the sub zero pressure dew point (PDP) of a typical regenerative desiccant dryer, with the low operating and energy costs of a refrigerant dryer, to provide an extremely low total cost of ownership (TCO). Sub zero air dryers take clean, dry air to new levels of cost-efficiency across a broad spectrum of operating conditions.
Optimised for Class 3 air quality
Many applications require very dry, high-quality air with sub zero dew points. CompAir’s desiccant dryers are the best option for the most stringent requirements – ISO Class 1-2 with a pressure dew point (PDP) as low as -70°C (-94°F). However, ISO Class 3 air, with a PDP of -20°C (-4°F), is sufficient for a large portion of the market. For applications that only require Class 3 air, we've expanded our family of high quality air dryers with our CMT dryers. They combine the ease of maintenance and operation of a refrigerated dryer with the sub zero pressure dew points typically associated with a desiccant dryer. Please download our white paper at the bottom of the dryers homepage to learn more about the ISO classes and how the apply to compressed air. Please contact us directly to get further information on this topic.
Features
Pre-Cooling
Air enters the dryer through the pre-cooler/re-heater
Regeneration
Leaving the pre-cooler/ re-heater, the air enters the first heat exchanger for regeneration
Drying
With only 15% of the of the moisture remaining, the air now enters the sub zero dryer heat exchanger where it is cooled and dried to -20°C (-4°F) PDP.
Reheating
The air dried to -20°C (-4°F) PDP is reheated before exiting the dryer in two steps.
A Sub-Zero Refrigeration Dryer is an advanced type of refrigerant compressed air dryer designed to remove moisture from compressed air by cooling, condensing water vapor and then reheating the air before distribution. What sets the Sub-Zero versions apart is their ability to achieve sub-zero pressure dew points (e.g., about –20 °C (–4 °F)) — much lower than standard refrigeration dryers — while maintaining the lower energy use and simplicity of refrigeration technology. This makes them very efficient for many industrial applications.
📌 How They Work (Key Principles)
Typical refrigerant compressed air dryers use a refrigeration circuit to cool incoming compressed air, condensing moisture out of it. After water is removed, the dried air is reheated slightly before it leaves the unit to reduce condensation in downstream piping.
Sub-Zero models add a two-stage design that deep-cools and regenerates air without desiccant media, enabling a much lower pressure dew point (~–20 °C).
⚙️ Main Benefits of Sub-Zero Refrigeration Dryers
❄️ Lower Dew Point Drying
Achieves sub-zero dew point around –20 °C (≈-4 °F), significantly drier than typical refrigerant dryers (~+3–10 °C).
Suitable for applications that require ISO Class 3 compressed air quality.
💡 Energy & Cost Efficiency
Uses refrigeration technology with much lower energy consumption than desiccant dryers.
Reduced total cost of ownership (TCO) due to energy savings and minimal purge/consumables.
🔧 Low Maintenance
Operates without desiccant materials, eliminating frequent replacements and complex purge systems.
Compact design and simpler components mean easier access and service.
🌡️ Reliable Moisture Control
Maintains consistent dry air quality across varying compressor load conditions.
Can protect pipelines and tools from freezing in lower ambient temperatures.
🧱 Typical Specifications (Example From CMT60 Model)
Feature Value
Dew Point –20 °C (–4 °F)
Pressure Dew Point Class ISO Class 3
Max Pressure Up to 14 bar
Refrigerant R452A (or optional variants)
Controller Programmable controller with connectivity (e.g., Modbus)
Capacity Range Typically several m³/min depending on model (e.g., 6–26.66 m³/min)
These specs will vary by manufacturer and model — many industrial suppliers provide multiple sizes for different flow rates and system capacities.
🏭 Typical Applications
Sub-Zero and other refrigerant compressed air dryers are used in many industrial settings where moisture-free air is critical:
Manufacturing & automation
Food & beverage processing
Automotive painting & assembly
Electronics & instrumentation
Packaging and pneumatic tools
The dry air prevents corrosion, improves tool life, and avoids moisture-related defects.
