Abstract:
In Ethiopia, Rural areas mostly used traditional wood burning stoves like open fire wood
burning stoves for cooking, space heating and lighting. The use of these forms of energy is
associated with environmental as well as human health impacts. Therefore, Improved /modified
cook stove are required to alleviate these problems. In this study, an improved single and
multiple wood burning stoves (double and triple) were designed, fabricated and tested to
evaluate their performances and to compare them with the conventional charcoal burning stove.
The energy efficiency and cooking times of each wood burning stove was determined indirectly
by cooking 242 g rice in a pot and by measuring temperature of rice in the pot, stove body
temperature and smoke outlet temperature every seven minutes. For each stove 350 g of ovendried
wood was used. The tests were replicated five times. For comparison, three parameters
(time of onset of cooking or time when the food temperature reaches 75oC, maximum
temperature reached and effective times of cooking or time range of T ≥ 75oC) were considered.
Comparisons of the three parameters were made by using one-way ANOVA followed by pair
comparisons wherever the ANOVA showed significant differences. Besides, relative heat losses
through the body of the stoves and the smoke outlets were determined by area calculation from
the plots using Matlab software. The results showed no significant differences in time to reach
75oC and the maximum temperatures reached among treatments at p=0.05 level. In terms of
effective cooking times there were significant differences between the fabricated and the
conventional stove, but no differences between the former. The single stove exhibited higher stove body temperature of 17% and 16% than the double and the triple stoves, respectively. The
double stove smoke outlets showed nearly 16% more heat loss than the single stove and about
half as much over the triple stove. The use of fabricated stove has an advantage of almost
doubling the effective cooking time as compared to the conventional stove.
