Experimental Analysis of Solar Thermal Tea Dryer

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Addis Ababa University


The tea drying is a heat transfer between the product and the surrounding to dry the leaf and make ready for market. Conventional tea dryer consumes too much energy since the water will be heated using the electric boiler. The main objectives of this research are to design, manufacture and test the performance of solar thermal tea dryer. The solar dryer was mathematically designed using the data gathered from the National Metrological Agency. The solar dryer was sketched on the solid work before it goes to the workshop for construction. The construction of the dyer was done in Addis Ababa Institute of Technology, Mechanical Engineering workshop. The designed dryer has a collector area of 1.3 and a ventilation area of 0.1 . The assessment has been done with scientific experiment using different measuring methods and tools at Addis Ababa Institute of Technology, Addis Ababa University, and Addis Ababa, Ethiopia. The solar radiation on the collector, the ambient temperature, the temperature on the solar collector, and inside the dryer chamber, including the wind speed were measured and analyzed. The sample products used to measure the performance of the dryer are Moringa (drumstick tree) and Ginger. Due to a problem countered in bringing tea leaves without losing moisture. The initial moisture content of the Moringa (drumstick tree) leaf was 50% and the final moisture content was 5.1%, and for Ginger the initial moisture content was 68% and the final moisture content was 13.1%. The total moisture removed from the sample products was 44.9 % and 43.9 % for Moringa and Ginger respectively. The drying rate for Moringa and Ginger is 0.27 ⁄ and 0.25 ⁄, respectively. The average collector efficiency is 36.3% and 22.1% with no load and with load, respectively. The total time taken to dry the products is 6 h. Finally, the overall efficiency of the dryer for drying Moringa and Ginger is 23.8% and 21.5%, respectively. The solar dryer could be used for drying other agricultural products after testing at different seasons especially when there is a high and low solar radiation and temperature to see the maximum and minimum performance of the dryer.



Solar Dryer, Moringa Leaf, Ginger, Solar energy, Solar collector, Drying chamber, Drying efficiency, Design, Manufacture