Muaz Bedru (PhD)Seniya Fedlu2024-07-312024-07-312024-07https://etd.aau.edu.et/handle/123456789/3334Post-harvest loss is one of the major problems that need great consideration to address challenge of food security. This issue is mostly common in Africa, especially in sub-Saharan Africa due to lack of electricity, high energy cost to income ratio and attempts to harnessing solar powered energy. However, Ethiopia is one of the high fruits and vegetables producing regions in Africa continent. But due to lack of proper storage around 20% of the harvested product gets spoiled since the region has a semi-arid climate condition which is unsuitable for storage of tomato. The safe storage temperature of tomato ranges between 18ºC to 22ºC. This temperature range can be achieved with refrigerators and evaporative coolers. However, the cost of refrigeration system is very high compared to evaporative coolers and they also consume large amount of electric power for the same cooling effect. Thus, considering that there is no electrical coverage in the farming areas, a solar powered evaporative cooler would be more suitable for storage of tomato in the region. A direct evaporative cooler with a capacity of 100kg is designed and its performance is studied with simulation on ANSYS Fluent. The effect of varying the thickness of the cooling pad, inlet velocity and inlet temperature on the performance of the cooler is studied. Three pad thicknesses (50mm, 75mm and 100mm), inlet velocities of (0.5m/s, 1m/s, 1.5m/s, 2m/s and 2.5m/s) and inlet temperatures (25℃, 27℃, 29℃ and 33℃) are considered. The result shows that larger pad thickness has a higher temperature drop at the outlet compared to the pad with smaller thickness. The cooling capacity and cooling effectiveness also increases as the thickness of the pad increases because increasing the thickness of the pad increases the heat transfer area. Increasing the velocity of the air at the inlet increases the outlet temperature. Increasing the inlet velocity also increases the cooling capacity and cooling effectiveness since increasing the velocity increases the flow of air which favors the heat transfer. Optimum cooling conditions foren-USSolar powered evaporative coolerCooling capacityEffectivenessANSYS FluentThesis