| Boiling Point No. 17 - December 1988 |
In the early days of 'improved stoves', the only way to test and improve a new design, whether in the laboratory or in the field, was by trial and error. The effect of changes could not be predicted because there was little or no understanding of how stoves worked and what were the critical dimensions. Several years of basic research were needed to learn the chemistry and physics of pyrolsis and burning; to determine the correct proportions of primary and secondary air, the effect of door openings, passages, chimneys, baffles, dampers, pre-heating, insulation etc. and how all these influence performance ie. the overall behaviour, controlability, fuel efficiency and versatility of the stove. Stove designers and manufacturers are now better able to minimise costs without affecting performance.
This technical understanding was needed before studies of user requirements and needs assessment could be made and it was realised that overall cooking times and heat control were at least as important to the housewife as fuel economy. The diversity of new designs from various parts of the world showed the need for standard test procedures and results which would permit independent comparisons by other stove programmes. The stove users or field workers are limited in what they can do to improve a metal or clay stove but in the case of mud stoves, much can be done to correct faults resulting from bad construction or installation. This issue of Boiling Point looks at what is being done to help stove workers 'optimize' new stoves and to see whether better guidelines can be prepared.
However, it is still evident that scientific analysis is not a substitute for practical experience and knowledge gained through kitchen discussions with users and workshop discussions with makers. Stove designing like cooking remains as much an art as a science.