Performance improvement of an electric injera baking pan (Mitad) using copper powder as additive material

Abstract

In this paper, the performance improvement of an electric injera baking stove is studied experimentally using copper powder as additive material for baking plate preparation. The performance of conventional electric injera baking stove is low because of the poor thermal conductivity of the backing plate material. This leads to a high energy consumption ranging from 1.23 to 1.41 kWh for initial heating and observed uneven temperature distribution on the baking surface. Therefore, this study focuses on reducing the time required for initial heating so that the energy consumption will be reduced which will result in overall thermal efficiency improvement. The composite material is developed in four different samples with mixture of different ratios of clay soil and copper powder. Then the performance is studied experimentally. The experiments are conducted for analyzing the initial heating time, plate surface temperature distribution and energy consumption. The results show that the composite material thermal conductivity property has been improved due to addition of copper powder. The sample with 20% copper powder and 80% clay soil ratio mixture has given a better overall performance than other composition (i.e. less initial heating time, better uniform baking surface temperature and less energy consumption/kg of injera). The thermal efficiency of the improved baking stove is 88.55% which is of Grade 1 as per the Ethiopian Standard ‘ES 04090 sub article 4.2 while that of the conventional electric baking stove is 53.36%. Hence, the addition of copper powder to clay has resulted in an overall improvement in thermal efficiency. The quality of injera baked is also very nice with bubbly eye in the front and smooth back side.