Energy Consumption of Beech Timber Drying in Oscillation Climates

The infl uence of applying the oscillations of air parameters during conventional drying of beech timber on energy consumption is discussed in the paper. A special drying software was created to enable the input of frequency (in hours) and amplitude (in percents) of oscillations. Altogether 12 drying runs were carried out: three conventional ones and nine by using the same schedule but with oscillations of equilibrium moisture content (EMC), temperature and the combination of these two. The combinations of two amplitudes (10 % or 20 %) and two frequencies (3 or 6 hours) were applied in different test runs. The results indicated that all test runs had energy consumptions proportional to drying time, with an important infl uence of the outside temperature. In runs with oscillations, often climate changes infl uenced to some extent the total energy consumption, especially in runs with short phases (3 hours) and high amplitudes (20 %). Despite frequent climate changes, it can be expected that the usage of oscillations would lead to the same or even lower energy consumption than in conventional beech timber drying, especially when shorter drying time is reached.