Air-circulation drying
The majority of timber is dried by circulating air. The necessary heat is normally produced in a heating plant nearby. The heat is transferred inside the kiln by blowing air through the stacked loads. Humid air acts as the medium that transfers heat and moisture.
This material enters into chamber and progress kilns.
High temperature drying
High temperature drying means drying where the temperatures used are over +100°C. In this method, steam acts as a medium of heat transfer into the dried timber.
Vacuum drying
Vacuum drying is based on water boiling in a vacuum at a temperature below +100°C. Fast drying at low drying temperatures is especially suitable for species that are difficult to dry without causing discolouration. These include oak, beech, birch and European ash. In vacuum drying, the drying temperatures vary between +50°C and +80°C.
Condensation drying
Condensation kilns can be seen as a variation of chamber kiln drying which is based on air circulation. In condensation drying, steam is not directed out of the kiln but blown to the condenser heat pump after which the steaming heat is returned back into the drying process. This method requires electrical energy that is more expensive than other forms of energy.
