Contoured Timber Kilns

Over the years many thousands of dollars has been spent on research into the problem of uneven airflows within timber kilns. Conventional shaped timber kilns, with squared corners and a square roof, are a major cause of the airflow problem.

The below diagram shows actual flow patterns within a kiln. The square corners create eddies, or the “Vortex” effect. This leads to uneven drying of the timber within the stack.

We have used computer simulations to better understand what happens inside timber kilns during drying.

The below diagram shows standard commercial ducting. Square ducting is 10 times more restrictive on airflow as curved ducting. This is the same problem when dealing with conventional shaped kiln. The airflow is restricted by the shape of the kiln.

One way to resolve this problem was to design a kiln that allowed airflow to move more uniformly through the entire kiln. Together with the Wood Technology Research Centre, University of Canterbury, a new kiln was designed that promotes even airflows down the stack, thus reducing the between-board range of moisture content.

The result is the Contoured Timber Kiln.

The Contoured Kiln has a smooth barrel-shaped roof and contoured internal features which are designed to streamline the airflow through the kiln and thus produce uniform flows in the timber stack. Significant improvements in the uniformity of airflow have been demonstrated in the new innovative kiln. Tests have shown a 17% decrease in drying times, with less fan power consumption than conventional kilns, which results in a substantial reduction in energy costs.