Determining and improving air movement profiles in a condensation type lumber drying kiln

Abstract

Drying of timber is an inevitable process in quality production. Today, there are drying kilns that their environmental conditions can be controlled. However, this control flexibility also brings with it attention to every variable in the environmental conditions. In this study, it was tried to determine the air movement speed of these variables, its effect on drying and the effect of the gap closing board (panel) placed to direct the air movement to improve drying conditions. In this context, approximately 10 m3 of oak lumber was dried in a dehumidifier (condensation) drying kiln with a semi-automatic control system. After drying, the moisture content of the lumbers were determined and the air movement speeds between the stack floors were measured with an anemometer from a total of 42 regions with all fans on, using two plenum chambers as a reference. The results obtained indicate that low quality or non-standard drying was carried out according to the moisture distribution criteria in the standards, as the ideal drying conditions were not achieved without installing the panel. It was determined that the air movement profile improved with the intervention made with the panel and the air was distributed more homogeneously between the stack floors. Despite the installation of panel, sufficient improvement in air movement speed could not be achieved only on the upper floors of the stack, due to a problem also mentioned in the literature. However, since only electricity is used for heating and air movement in the kiln, the electrical energy consumed during drying was also measured and correlated with the outdoor temperature in order to raise awareness. The results showed that consumption data did not change according to changes in weather conditions. It was thought that the kiln insulation performance and/or the kiln being located in a closed area were effective in this situation. It was concluded that the increased average energy consumption in the second half of drying might be according to the condensation device being activated more related to the more severe conditions required in the drying program.

Keywords

• rutubet dağılımı
• hava hareket hızı
• anemometre
• enerji tüketimi
• moisture distrubition
• air velocity
• anemometer
• energy consumption