Potential assessment and experimental analysis of solar vegetable dryer: in case of northern Ethiopia

The traditional vegetable drying (open-air/sun drying) method of harvesting of tomato, potato and onion in the Fogera District in Amhara regional state, Ethiopia, leads to loss of product, reduction in the quality of product and economic loss for the poor farmers. So, this experiment aimed to show the effectiveness of solar dryer technology by increasing the quality of the product in tomato, potato, and onion in Fogera district Northwest Ethiopia, 2018. A simple solar vegetable dryer is experimentally analyzed to alleviate the problem associated with vegetable processing in Woreta city. The first law of thermodynamics energy analysis was carried out to estimate the amount of useful energy gained from solar air dryer and energy utilization ratio of the drying chamber and the energy through drying box. The magnitude of the exergy inflow, outflow and exergy losses in the drying chamber during the drying process was determined by applying the second law of thermodynamics. The average solar drying efficiency was found to be 75.01% to 86.70% for tomato, 75.70% to 87.90% for potato and 58.7% to 85.5% for onion. Regrading the drying period, it took 33 h for tomato, 27 h for potato and 44 h for onion during the experimental test.