Simplified Model for Lighting Cone Design

Some types of biomass stoves, such as charcoal stoves, tend to be difficult to light due to poor initial draft and sensitivity to ambient wind. Decreasing the time necessary to light such stoves could increase user acceptance and convenience and decrease the user’s exposure to harmful emissions, as ignition is one of the smokiest portions of a cooking fire and may require close tending attention. A device known as a lighting cone has proven to aid ignition in such stoves, while also being inexpensive and easy to build in the field. This paper provides a basic model for estimating flow velocities produced from lighting cones in relation to the lighting cone dimensions and thermal power. Flow rates through a lighting cone measured empirically are compared with the model to evaluate the validity of using a simplified equation. The average percent error between theoretical and empirical thermal powers was found to be less than 15%. Thus the proposed model could be a useful starting point for sizing prototypes in the laboratory and in the field.