The Simple Philosophy of Heatless Desiccant Dryers for Compressed Air
Drying compressed air through adsorption represents a purely physical process in the course of which water vapour is bound to the drying medium (desiccant) through binding forces of molecular adhesion. For adsorption to take place, moist air is directed through the adsorber at various operating pressures. During this process, the moist compressed air comes into contact with the hydrophilic desiccant molecules when it flows from the bottom to the top of the vessel. The desiccant molecules will retain the moisture which results in dry compressed air leaving the vessel.

AFE HDD Dryer Control Systems for Heatless Desiccant Dryers
AFE offers two control systems for the HDD desiccant dryers:
1. PLC (Programmable Logic Controller System)
The HDD dryer is available with a time based PLC Control as standard. The standard cycle times are 5 minutes of adsorption followed by 4 minutes of regeneration and  1minute for pressure build up.
2. LCS (Load Control System)
The LCS is a more economical system with energy saving features. Instead of re-generating every 5 minutes in a time controlled PLC system, the LCS uses a dew point sensor which detects the moisture load of the compressed air at the outlet. The system then re-generates only when the dew point is higher than the set level. This saves purge flow and therefore energy.