Design, Construction and Performance Evaluation of a Biomass Fired Oven

ABSTRACT Baking and roasting are important cooking operations domestically and commercially carried out in bakeries, eateries and homes. It involves cooking with hot air as a result of heat and mass transfer processes. Baking and roasting of food items could be done using an oven. Therefore, this work is aimed at harnessing agricultural waste materials as heat sources in oven cooking and baking operations. The design, construction and performance evaluation of a biomass fired oven was undertaken. The oven consists of a baking chamber and a detachable combustion unit. The baking chamber and combustion unit were constructed using mild steel sheet of 4mm thickness with internal dimensions 50×50×35cm and 25×25×10cm respectively and with a total external dimensions measuring 56×55×61cm. The oven is insulated with fibreglass material in order to prevent heat loss to the environment. The oven was evaluated using biomass- charcoal, rice husk and sawdust briquettes as heating materials in order to determine the efficiency of the oven. Other tests include determination of baking time, specific fuel consumption, temperature profile and impact assessment of the baking system on the environment. The result of the performance evaluation showed that the time taken for baking was lowest using charcoal at 75 minutes for cake and 30 minutes for bread, while rice husk and sawdust briquettes took 92 and 85 minutes, and 32 and 31 minutes for cake and bread respectively. The specific fuel consumption and thermal efficiency of the oven were also lowest with charcoal and highest with rice husk briquettes. The particulate matter (PM2.5), carbon monoxide (CO) and carbon dioxide (CO2) emissions were highest for rice husk briquettes and lowest for charcoal. It is recommended that the oven be made available for cooking and baking operations in bakeries, eateries and homes. Its availability will minimize dependence on electricity and environmental pollutions caused by other cooking systems.