A Direct Solar Fryer for Injera Baking Application
Abstract
Injera is a traditional staple pancake and it is part of the daily dish to most of the one hundred million population in Ethiopia and Eritrea. The conventional baking method uses either biomass in rural areas or Electricity in majority of urban areas. A direct solar fryer for Injera baking application is developed as an alternative to the conventional baking methods. The solar fryer system uses a 1.8m rim diameter dish covered with aluminum reflective sheet. The system employs an aluminum baking plate of 550 mm diameter, 12.5 mm thickness and is equipped with two axis manual tracking. The direct solar fryer model has two possible operational modes; the continuous heating-baking mode and the alternating heating-baking mode. The experimental result show that the initial heating up time in both modes was in the range of 30 to 45 minute and this initial heat up time was comparable to the conventional baking process. In the initial heat up period, the plate has reached an average temperature of 120 to 130 ℃ in the continuous type model and 160 to 180 ℃ in the alternating type model, which was sufficient surface temperature to initiate a baking activity. The baking process in the continuous type model has taken an average of 5 minutes while the subsequent additional heat up time was 2 minutes giving an average baking time of 7 minutes per Injera. The alternating type model has slower heating time at each consecutive baking activity. The direct solar fryer will provide a baking power of 563W with a system thermal efficiency, including the collector efficiency of 37 %.