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Tropentag 2008, October 7 - 9, Hohenheim, Germany

"Competition for Resources in a Changing World - New Drive for Rural Development"

Study on Drying Cloves (Syzygium aromaticum) using Greenhouse Effect Solar Dryer Integrated by Biomass Energy

Rita Khathir1, Wolfgang Luecke2, Edi Hartulistyoso3, Leopold Oscar Nelwan3

1Syiah Kuala University, Agricultural Engineering, Indonesia
2Georg-August-Universität Göttingen, Institute of Agricultural Engineering, Germany
3Bogor Agricultural University, Agricultural Engineering, Indonesia


A study on drying cloves (Syzygium aromaticum) was conducted in Bogor, Indonesia, in November, 2008. The purpose of this study is to evaluate the performance of GHE-hybrid dryer applying greenhouse effect mechanism and biomass energy to improve drying air temperatures, and electricity to force the drying air. The GHE-hybrid dryer tested is a deep bed crop dryer represented by 10 series of thin layers covered by polycarbonate sheet. The dryer is supported by 2 axial fans and a biomass stove. The biomass stove is equipped by 99 baffles functioning as heat exchanger. For each drying batch of 1 cm thickness, the drying capacity is 144 kg of cloves. The temperature of drying air from the collector varied between 28 and 52°C and cloves could be dried in 42 hours (6 days) where drying process was run intermittence during the day. Drying chamber temperatures varied in average between 36 to 46°C. The different temperatures among 10 layers were from 3 to 12°C. Air velocity found in drying chamber was in range of 0.04 to 2.09 m/s by average of 0.68 m/s. Thermal efficiency is found about 15%, and drying efficiency is around 23%. Based on the cloves initial moisture content of 71.32%, the energy specific found was 16.79 MJ per kg of evaporated water. The energy input was dominated by the use of biomass energy (75%) since the research was conducted during the beginning of rainy seasons. Solar energy contributed about 15% and electricity shared about 10%. It was estimated that due to the variation of temperatures, air velocity, and humidity in the drying chamber the final moisture content wet basis varied highly from 0.2% to 19.2%.

Keywords: Biomass energy, cloves, solar dryer, greenhouse effect

Contact Address: Rita Khathir, Syiah Kuala University, Agricultural Engineering, Jln. Tanjong Selamat No. 8 Darussalam, 23373 Banda Aceh, Indonesia, e-mail: ukhti79@yahoo.com

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