Anagama Kiln - Characteristics of Climbing Kilns

Characteristics of Climbing Kilns

The main advantage of climbing kilns is that heat from the burning fuel is re-used, the same heat heating more than one part of the kiln. Exhaust heat created during firing of the lower part of the kiln, preheats the chambers above. In addition, the cooling ware and walls below preheat the incoming air. Thus, firing of ware in the upper chambers requires only the additional fuel needed to bring the ware, walls and air to peak temperature. (From a thermodynamic point of view, the higher temperature of combustion and cooler exhaust suggest greater efficiency.) A modern type, called a tube kiln improves the efficiency and output still further by having the ware move through the kiln in a direction opposite to that of the hot gasses.

All of these kilns use two counter-flow exchange mechanisms to maintain the air supply and to change the ware being fired, with minimal loss of heat. Each of these exchanges works on the same principle as countercurrent exchange, the principal difference being that the ware is not a fluid.

An advantage of the chambered and semi-chambered variants appears to be that they are partly downdraft, which makes the firing results less sensitive to the way the ware is loaded.

A disadvantage of (small) climbing kilns is a tendency to rapid cooling, caused by the incoming air.