<論文>木材の調湿効果に及ぼす換気の影響

Abstract

木材を内装した鋼製の箱の上面に設けた吸排気口を通して一定間隔で換気を行いながら箱の外周部温度を変化させた時の箱内の温度と相対湿度を測定した。箱の外周部の温度変化は15℃～25℃の範囲とし,相対湿度の変化は温度が20℃のときの相対湿度を65%とし,絶対湿度が一定とみなして求めた。相対湿度の対数を温度の一次式で近似し,その勾配Bによって木材による箱内の調湿の程度を評価した。B値,気積率および換気回数の関係を測定した結果,B値は換気回数が増すとともに小さくなり,B値に及ぼす気積率の影響は少なくなった。また,材料表面からの吸放湯量は,気積率が小さく,換気回数が増すほど多くなることが類推された。

The relative humidity and temperature in the steel box lined with wood which had two ventilating pipes (exhaust and inhalant pipes) on its upside were measured during ventilation at constant intervals when its ambient temperature was periodically changed in the range from 15℃ to 25℃ for 24 hours. The changes of relative humidity with the changes of temperature outside of the box were estimated by assuming a constant absolute humidity. The logarithm of relative humidity in the box was approximately represented by a linear equation of temperature. The extent of humidity conditions by wood in the box was evaluated by the slope B of the equation. The relationship between the B-value and the ratio of area lined with wood (A) to volume (V) of the box (A/V) or the number of air changes was invesigated. With increasing the number of air changes the B-value decreased and the effect of A/V on the Bvalue reduced. It was estimated that the amount of moisture absorption and desorption of wood increased with decreasing A/V and with increasing the number of air changes.