Evaporation and Humidification

Abstract

The amount of moisture in the surrounding air has a crucial bearing on the rate at which a piece of wet wood will dry out. The ratio of water vapour to dry air, on a mass basis, is called thehumidity. This quantity is dimensionless, but at low moisture-vapour levels it is often convenient to record humidities in grams water vapour per kilogram of perfectly dry air. Sometimes values of the absolute humidity are reported on a volume basis. However, it is easier to follow changes in humidity throughout a kiln on a dry-air basis, since the mass of circulating moisture-free air is not altered by the drying process.