Abstract:
In many of the developing countries including Sub-Saharan Africa, most of the improved cook stoves were
designed by considering only wood fuel, and as such are not suitable for using husk type biomass available
aplenty such as coffee husk, rice husk, saw dust, etc., which get generated sustainably. While some stove
eversions have been reported for using briquettes and pelletized biomass employing husks, others such as gasifier
stove versions have been reported which mostly are suitable for only batch feeding of husk type biomass. A
continuous feed type husk biomass cook stove has been developed and thoroughly evaluated in this study for
clean burning at high altitude condition in Ethiopia. The water boiling test (WBT) and emission tests were
conducted for a detailed stove performance evaluation. The experimental testing was carried out using two pots
with different sizes both for coffee husk and rice husk biomass employing water boiling test version 4.2.3 pro tocols. The WBT experimental results indicate that for a 3.5 l pot, the average thermal efficiency and time to boil
water are 29% and 7.7 min for coffee husk where as 28% and 8.4 min for rice husk, respectively, during the hot
start phase. The maximum CO emissions of the stove measured are 262 ppm and 235 ppm using coffee husk and
rice husk biomass, respectively, during the simmer phase. The international workshop agreement (IWA) norms
applied to classify the performance of the stove, and the result indicated that the average indoor CO emissions
were 0.186 g/min and 0.274 g/min using rice husk and coffee husk biomass, respectively. The average specific
fuel consumption for this stove was 98 g/lit, which is better than the improved biomass cook stove, in which
specific fuel consumption was 115 g/lit. The total selling price of the husk biomass cook stove developed
amounts to 6.72 USD.
