The series DD-Dry Tech dehumidifiers, dehumidify the air inside hoppers to dry the reasing, at a Dew point depending on the size of the plant and the requirement of the client to reach the (Dew Point) at 50C°. A modified version will enable the Dew Point to reach-60C°. The temperature control and the dehumidification process is guaranteed. Accuracy is enhanced by way of micro-processor which provides operators with a visual read-out of all functions and alarms. The cartridge recycle process is fully automatic, making the operation as easy as possible for the operator to set the temperature for the process of the dehumidification and alarms. The closed circuit of the cooling system eliminates any re-humidification occurring in the cartridge.