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.

The availability of properly analyzed energy resource potential data is a prerequisite in energy planning and development. However, this was sparsely applied in Ethiopia’s renewable energy turnkey project development strategies. This study focuses on developing a solar energy resource map of Tigray to accelerate the expansion of solar energy to improve electricity access through on-grid and off-grid development schemes. This study uses monthly sunshine hour data from sixteen meteorological stations, measured at a 2 m height, and average yearly solar radiation data from twenty-two satellite stations, validated by solar radiation data and measured at three sites at 10 and 30 m heights. The solar energy potential was analyzed by taking relevant atmospheric and meteorological factors to produce solar radiation components. Accordingly, the average annual solar radiation of Tigray was found to be 6.1 kWh/m²/day and 5.3 kWh/m²/day based on meteorological and satellite data, respectively. The meteorological result gave a closer estimate to Ethiopia’s ESMAP Global Solar result of 5.83 kWh/m²/day. Finally, monthly and annual average solar radiation maps of the region were developed using ArcGIS10.5. The study’s results could contribute to assisting various solar energy developers in preparing better solar energy development plans to alleviate the chronic energy poverty of the region.

This study presents an experimental performance evaluation of an oil-based indirect solar fryer system designed for injera baking. The system consists of a receiver vessel, a closed-loop delivery and return pipe network, and a 60 cm diameter aluminum baking plate with spiral grooves on its bottom surface. Heat transfer oil circulates within the closed loop to transfer thermal energy from the receiver to the baking plate. The system was experimentally investigated under controlled electrical heating conditions using input power levels of 1.0, 1.3, 1.6, 1.75, 2.0, and 2.4 kW, representing equivalent solar thermal input scenarios with varying intensity. The results confirmed the technical feasibility of the system for injera baking across all tested conditions, with performance strongly dependent on input power. At higher input levels (≥2.0 kW), faster heating and shorter baking cycles of approximately 2.5–3 min were achieved; however, increased oil temperatures and thermal instability were observed due to limited heat redistribution within the fixed low-flow circulation system. At lower input levels (≤1.3 kW), the system remained thermally stable but exhibited long initial heating times (up to approximately 85 min) and reduced operational efficiency, limiting its practical applicability. The most balanced performance was observed at intermediate input power levels of 1.6–1.75 kW, where the system achieved approximately 45–60 min initial heating time, stable temperature behavior during operation, and consistent baking cycles of about 3 min with 1 min reheating time. This range provided an optimal compromise between thermal efficiency, operational stability, and energy utilization under the present configuration. Overall, the study demonstrates that the indirect solar fryer system is a promising alternative for energy-efficient injera baking; however, performance is strongly influenced by thermal input and circulation conditions, highlighting the need for further optimization and validation under real solar operating environments.