국산 낙엽송 및 신갈나무의 열기건조 소요에너지 평가

Abstract

This study evaluated the energy efficiency of kiln drying for two major domestic wood species, larch (Larix kaempferi) and oak (Quercus mongolica), by comparing the theoretical heat energy required for drying with the actual electricity consumption. Kiln drying was conducted using 50-mm-thick lumber, applying a modified Forest Products Laboratory (FPL) schedule suitable for the two species. Moisture content changes were monitored daily using designated MC samples. As a result, larch was dried from an initial moisture content of 34.4% to 8.0% over 192 hours, while oak required 1,224 hours to reach 9.2% from an initial moisture content of 62.1%. Based on the heat energy classification proposed, the theoretical heat energy required for drying was calculated as 1,434.9 MJ for larch and 5,087.0 MJ for oak. Actual electricity consumption was 2,345.8 MJ and 7,738.6 MJ, respectively, resulting in energy efficiencies of 61.2% for larch and 65.7% for oak. Despite the considerably longer drying time for oak, both species exhibited similar energy efficiency, indicating that the efficiency of kiln drying is more influenced by the characteristics of the drying system than by wood species. However, the 50-day drying period required for oak highlights limitations in its practical utilization, suggesting the need for further studies on advanced drying techniques such as vacuum radio-frequency or microwave drying for heavy hardwoods.