Heatless Desiccant Air Dryers
Industrial heatless desiccant air dryers use dry compressed purge air to regenerate the desiccant without an external heater or blower, providing reliable low dew point air with a simple twin-tower design.
Lingyu provides industrial heatless desiccant air dryers for compressed air systems requiring low pressure dew points with simple and reliable regeneration. The CH and HH Series use dry compressed purge air to regenerate the desiccant without an external heater or blower.
Standard CH Series capacities range from 3.8 to 150 m³/min (approximately 134 to 5,297 CFM), while the HH Series covers 1.5 to 130 m³/min (approximately 53 to 4,591 CFM). For large-flow industrial projects, custom-engineered heatless desiccant air dryer systems are available with capacities up to 15,900 CFM.
Depending on the selected series and operating conditions, Lingyu heatless dryers provide low pressure dew point performance for instrument air, electronics, chemical processing, precision manufacturing, pharmaceuticals, and other moisture-sensitive compressed air applications.
It uses high-performance pneumatic valves, good adsorbent materials, and electronic controllers, which are simple to operate, have low operating noise, and have long service life.
High-Performance Pneumatic Valves:Reliable and responsive pneumatic valves ensure fast switching, stable operation, and long service life.
High-Torque Pneumatic Actuators:High-torque aluminum alloy pneumatic actuators provide smooth, reliable operation.
High-Performance Desiccant:Premium desiccant offers excellent adsorption capacity and abrasion resistance, ensuring a stable dew point over long-term operation with minimal dusting.
Intelligent Programmable Control:Equipped with a fully electronic programmable controller featuring an intuitive interface for easy operation and maintenance.
Low-Noise Operation:Low-noise check valves and high-performance silencers minimize operating and exhaust noise.
Automatic Repressurization:Before valve switching, the system automatically repressurizes and equalizes the pressure between the vessels. This ensures stable vessel pressure, minimizes pressure fluctuations and impact on the desiccant, and helps extend desiccant service life.
High-Performance Pneumatic Valves:Reliable and highly responsive pneumatic valves provide fast and stable switching with a long service life.
High-Torque Pneumatic Actuators:High-torque aluminum alloy pneumatic actuators ensure smooth, stable, and reliable operation.
High-Performance Desiccant:Premium desiccant provides excellent adsorption capacity and abrasion resistance, ensuring a stable pressure dew point over long-term operation with minimal dusting.
Intelligent Programmable Control:Equipped with a fully electronic programmable controller featuring an intuitive interface for easy operation and maintenance.
Low-Noise Operation:Low-noise check valves and high-performance silencers minimize noise during both normal operation and exhaust.
Automatic Repressurization:Before valve switching, the system automatically repressurizes and equalizes the pressure between the vessels. This ensures stable vessel pressure, minimizes pressure fluctuations and impact on the desiccant, and helps extend desiccant service life.
Heatless desiccant air dryers remove water vapor from compressed air through Pressure Swing Adsorption (PSA). Unlike heated regeneration dryers, they use a portion of the dried compressed air to regenerate the desiccant without an external heater or blower.
Lingyu CH and HH Series heatless desiccant air dryers provide an average purge air consumption of 8–14% and are designed for industrial applications requiring low pressure dew points with a simple twin-tower regeneration system.
They are commonly used for instrument air, pneumatic controls, electronics, chemical processing, precision manufacturing, and other moisture-sensitive compressed air applications.
A heatless dryer uses two desiccant towers that alternate between drying and regeneration.
Adsorption: Wet compressed air passes through one tower, where the desiccant adsorbs water vapor and dry compressed air flows downstream.
Regeneration: A portion of the dry compressed air is expanded to near atmospheric pressure and passed through the second tower. This purge air removes the moisture previously adsorbed by the desiccant.
Repressurization & Switching: Before the towers switch, the regenerated vessel is repressurized and pressure is equalized between the two towers. The cycle then repeats automatically to provide continuous dry compressed air.
No external heat is required during regeneration.
| Parameter | CH Series | HH Series |
|---|---|---|
| Drying principle | Pressure Swing Adsorption (PSA) | Pressure Swing Adsorption (PSA) |
| Capacity | 3.8–150 m³/min | 1.5–130 m³/min |
| Approx. capacity | 134–5,297 CFM | 53–4,591 CFM |
| Rated inlet pressure | 0.7 MPa | 0.7 MPa |
| Operating pressure | 0.6–1.0 MPa | 0.6–1.0 MPa |
| Rated inlet temperature | 10–30°C | 10–30°C |
| Maximum inlet temperature | ≤40°C | ≤40°C |
| Average purge air | 8–14% | 8–14% |
| Pressure dew point | -50°C to -20°C | ≤-40°C |
| Desiccant | Activated alumina | Activated alumina + high-performance molecular sieve |
| Rated ambient temperature | 35°C | 35°C |
| Ambient operating range | 2–45°C | 2–45°C |
For applications beyond the standard CH and HH Series ranges, custom-engineered heatless desiccant air dryer systems are available for project capacities up to 15,900 CFM, as well as special operating pressures and site requirements.
Heatless dryers require very little electrical power for regeneration because no heater or blower is used. However, part of the dried compressed air is consumed as purge air.
The Lingyu CH and HH Series specify an average purge air consumption of 8–14%.
For example, for a dryer processing 100 m³/min:
| Average Purge Rate | Approx. Purge Air |
| 8% | 8 m³/min |
| 10% | 10 m³/min |
| 12% | 12 m³/min |
| 14% | 14 m³/min |
This purge air has already been compressed, so it represents an indirect energy cost at the air compressor.
For smaller systems or applications where simplicity is the priority, heatless regeneration can be an economical solution. For larger systems operating continuously, the cost of purge air should be compared with the heater or blower energy required by other regeneration technologies.
| Factor | Heatless | Externally Heated |
| Regeneration method | Dry compressed purge air | Heater + purge air |
| External heater | No | Yes |
| Average purge air* | 8–14% | 4–8% |
| Regeneration electrical demand | Very low | Higher |
| System complexity | Lower | Higher |
| Maintenance | Simpler | Heater system also requires maintenance |
| Initial investment | Generally lower | Generally higher |
| Main operating cost | Compressed air loss | Heater power + reduced purge air |
| Typical selection | Small / medium or simple systems | Medium / large continuous systems |
*Based on Lingyu CH / HH technical data for the corresponding heatless and externally heated series.
Neither technology is automatically more energy-efficient in every application. The correct choice depends on airflow, annual operating hours, compressor efficiency, electricity cost, required PDP, and maintenance requirements.
Key selection parameters include:
For applications requiring a PDP within approximately -50°C to -20°C, select the appropriate CH Series configuration according to the required air quality.
For applications requiring ≤-40°C PDP, the HH Series uses activated alumina combined with high-performance molecular sieve.
For high-flow systems operating continuously, purge air consumption should also be included in the selection calculation.
Lingyu CH and HH Series specify an average purge air consumption of 8–14% under the applicable operating conditions.
The CH Series specifies a pressure dew point range of -50°C to -20°C. The HH Series is designed for ≤-40°C PDP.
No. Heatless regeneration uses a portion of the dried compressed air to regenerate the desiccant, so no external regeneration heater is required.
The CH Series uses activated alumina. The HH Series uses activated alumina combined with high-performance molecular sieve.
Heatless dryers use more compressed air for regeneration but do not require heater power. Externally heated dryers use an external heater to reduce purge air consumption. The better choice depends on system size, operating hours, and energy costs.
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