Heat consumption for the drying mode of beech lumber in chamber kilns without changing the color of the wood

The study analyzes the energy intensity of the hot-air drying mode for beech lumber in the thickness range of 32–60 mm, with a particular focus on preserving the color of the wood. The suggested drying schedule is extended by ∆τ = 35 hours compared to the procedure outlined in the ON 49 0651 standard. This prolongation is due to the reduced temperature of the drying air during the phase of free water evaporation. The specific heat consumption for the proposed drying schedule is QTZN = 303.9 kWh·m⁻³, which is 26.16 kWh·m⁻³ higher than the consumption specified by the ON 49 0651 standard. The increase in energy use results from an 8.9-fold higher energy requirement for water evaporation from the wood, which outweighs the energy savings from reduced heat demand for lumber heating, initial air heating, air humidification at the start of drying, and compensating for the thermal losses of the dryer.