Effect of wood moisture content on the performance of wood burning cook stoves

Abstract

Rural Ethiopian communities rely mostly on biomass fuels for subsistence and productive purposes. With an increasing population and dwindling forest resources, wood fuel consumption has exceeded its supply. Besides, people do not know ways of maximising biomass efficiency. The study involves the burning efficiencies of woods with varied moisture contents. Eucalyptus wood of five different moisture contents was used in five identical wood-burning stoves purposefully constructed for this purpose. Tests were conducted over 5 days, thereby giving five replications. In the tests, food temperature, stove body temperature, and stove smoke outlet temperature measurements were conducted along with ambient air temperatures. Wood with 10% moisture content performs better during combustion with respect to low and high moisture content wood. High moisture content delayed the cooking onset and low moisture decreased the duration of effective cooking. The 50% moisture content or greater with respect to oven-dried wood failed to cook. Moisture content of around 30% delayed the time to reach cooking temperature by two and hence elongated the cooking time. There is also the extended smoke time as observed from the smoke outlet temperature.

Keywords

• cooking time
• cooking temperature
• stove efficiency
• wood moisture content