In 2011 in the Austrian Mühl-quarter, we were able to implement herb drying based on the circulation method with the inclusion of an air dehumidifier. On several days, the herbs were spread over an area of 56m² and carried out via a conveyor belt upon drying and then packed in sacks. A pressure channel was placed under the conveyor belt, which used a 22 kW ventilator to blow up to 55,000m³ per hour which was distributed equally.
The air flows through the goods to be dried and finally an air humidifier is introduced which reduces humidity by up to 60% and increases the temperature by up to 10°C and finally the ventilator is introduced. The electrical energy is produced by an electric power unit, the heat produced is used in the system.
The temperature is regulated by a controlled fresh air inlet, and hood suction is integrated in the system. System control is completely automatic, there is no need for heating by using oil or wood for herb drying.
Results after four weeks of using herb drying method
Using the old version (hop kiln), the electricity for the ventilators and hot air ovens came from the public electricity net. Our herb drying method used only 50% of the original energy used. For customers in upper Austria, this meas an oil saving of over 5,000 litres annually.
With the same drying temperature (for example 42°C for peppermint) the customer needed 20 hours for drying using the old system, but the new system manages it in 12 hours, which is equal to a time saving of 40%! Or conversely, 40 to 50% more capacity with the same energy consumption!
An additional bonus is the improved aroma obtained through this herb drying method!
The system mentioned here is also suitable for use in hop drying.
You can find out more information and a scheme for herb drying in our hay drying catalogue, which you can order here, free of charge.
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