During the design of this line of refrigeration air dryers one theme was kept central: energy efficiency. When using the level controlled condensate drains (standard as from EDU 500 upwards) an unnecessary loss of expensive compressed air is prevented. Furthermore the refrigeration air dryers are supplied with the unique Trisab aluminium heat exchanger. The specific advantages are as follows: Efficient and low energy cooling of the compressed air via the two-stage heat exchanger. Due to relatively large flow channels the pressure drop is extremely low and the refrigeration air dryer is not easily affected by pollution. The system is supplied with an overloading reservoir thus ensuring a constant pressure dew point, even in varying load and intensive use. Optimal condesate separation.