An Experimental Comparative Study of Large-Sized Direct Solar Fryers for Injera Baking Applications

Abstract

This research experimentally demonstrates the practicability of using large-sized direct solar frying as an alternative technology for the predominantly biomass-based injera baking method. The system was designed and developed with fryers 40, 50, and 55 cm in diameter and two operational options: continuous mode and alternating mode. Extensive experimental testing was conducted on each prototype to demonstrate solar frying and determine the relative performance. The findings indicate that the 2 kW heating capacity of the 40 cm-sized solar fryer model conducted baking processes at a relatively lower system temperature in both application modes compared to the larger-sized fryers. As a result, this system maintained a consistent average fryer temperature distribution and shorter initial heating time, without the requirement of a reheating process during the subsequent baking cycles. The experimental testing also demonstrated that alternating-mode applications were more practical for the 40 cm-sized fryers than for the larger ones. Overall, direct solar frying is more efficient and convenient for the 40 cm-sized solar fryers. In contrast, the larger-sized systems required a larger fryer thermal storage capacity coupled with larger-size solar concentrators to maintain equivalent stable operational conditions, conversely leading to a lack of application simplicity and higher system costs.