ABSTRACT
In recent years there has been an increased awareness to conserve energy through efficient use of fuels, energy saving devices and insulation against heat losses. Consequently, the construction of a rocket stove was undertaken in this research and the thermal property tests for ash and clay-sawdust insulation materials were carried out, after which the effect of these insulation materials on the thermal efficiency of the rocket stove was experimentally determined using cooking tests (water boiling test, control test and kitchen performance test). Both the ash and the clay-sawdust showed the ability to be used as insulators in the rocket stove; having low thermal conductivities (0.2W/mK and 0.16W/mK respectively), high specific heat (889J/kgK and 910J/kgK respectively) and low thermal diffusivity (3.67e-7/m2s and 1.58e-7/m2s respectively). When the ash and clay-sawdust were used in the rocket stove the thermal efficiency of the stove has a value of 21.6% and 22.28% respectively (for cold start), 46.34% and 44.06 % respectively (for hot start) and 20.00% and 23.91% respectively (simmering phase). This shows a great improvement when compared with the stove without insulation 10.86% (cold start), 17.70% (hot start) and 14.50% (simmering). The burning rate (5.30g/min, 5.24g/min for ash and clay-sawdust respectively, 10.72g/min for the stove without insulaion), firepower (2.36Watt and 2.34Watt for ash and clay-sawdust respectively, 5.25Watt for the stove without insulation) and specific fuel consumption (0.038 and 0.039 for ash and clay-sawdust respectively, 0.13 for the stove without insulation) all improved when there was insulation around the rocket stove. This shows that both ash and the clay-sawdust can be used as insulation material in the rocket stove and they improve the thermal efficiency of the rocket stove. The clay-sawdust insulated stove performed better than the ash insulated stove, having better thermal properties as shown above and gave better results when the water boiling tests were carried out.