The objectives of this study were to determine a suitable thin layer drying model to describe the drying kinetics of Guazuma ulmifolia leaves and determine the mass transfer parameters of Guazuma ulmifolia leaves. The drying of Guazuma ulmifolia leaves was conducted in a laboratory scale dryer with various temperature (40oC, 50oC, and 60oC) and relative humidity (30%, 40%, 50% and 60%). Five drying models, namely, Newton, Henderson and Pabis, Page, Midilli-Kucuk, and Verma et al. were fitted to the drying data. The drying curve of guazuma leaves did not show a constant drying period during the drying period. The models suitability were compared base on coefficient of determination (R2), root square mean errors (RSME), and reduced mean square of deviation (X2). It was found that, among the models evaluated, the Midilli and Kucuk model is the best to describe the drying kinetics of Guazuma ulmifolia leaves. The effective moisture diffusivity was found to be in the range of 10-13 – 10-12 m2/s and the convective mass transfer coefficient was in the range of 10-9 – 10-10 m/s. The activation energy value was found to be 89.21 kJ/mol.

Abstrak . Tujuan dari penelitian ini adalah mendesain dan membuat pengering tipe bak dengan sumber panas berasal dari tungku sekam kopi dan kolektor surya untuk pengeringan biji kopi, menguji kinerja dan menghitung konsumsi energi pengeringan alat yang telah dihasilkan dan menghitung biaya pokok pengeringan biji kopi dengan menggunakan alat yang telah dihasilkan. Penelitian ini terdiri dari 3 (lima) tahapan meliputi; (1) rancangan struktural dan fungsional pengering tipe bak, tungku dan kolektor surya, (2) konstruksi alat hasil rancangan, (3) Uji fungsional. Hasil penelitian ini adalah pengering surya tipe bak yang telah berhasil dirancang bangun. Selama 10 hari pengujian, dapat diketahui bahwa pengering dan kolektor surya sudah berfungsi dengan baik. Pengering ini masih banyak dipengaruhi oleh cuaca sehingga penggunaan tungku biomassa sebagai suplemen energi sangat diperlukan. Suhu udara rata-rata pengering atau bak yang dihasilkan berkisar antara 36,2 C sampai 48,6 C, sedangkan kelembaban relatif (RH) berkisar 43,6%-72,6%.  Design of Hybrid Dryer With Batch Type for Coffee Beans Abstract. The main aim of this study was to design and develop hybrid dryer in which heat sources are coming from coffee husks furnace and solar collectors used for coffee beans drying. We also tested its performance and calculated the energy consumption produced and total costs required to perform coffee beans drying. The study consisted of three stages; (1) structural and functional design of drying chamber, furnace and solar collector, (2) dryer construction and development, (3) functional test. The overall results of this study showed that solar collector was effectively working properly during the ten days drying. Yet, this developed dryer is still heavily influenced by the weather, and thus the use of biomass as an energy supplement is needed. The average air temperature produced by the dryer ranges between 36.2 oC to 48.6 oC, while the relative humidity (RH) ranging from 43.6% -72.6%.

AbstrakKajian ini bertujuan untuk menentukan kinerja penukar panas tipe shell and tube dengan pengaturan suhu outlet. Penukar panas yang digunakan dalam kajian ini adalah penukar panas tipe shell and tube dengan bahan bakar kerosen. Parameter kinerja yang dianalisis adalah konsumsi kerosen, suhu keluaran, koefisien perpindahan panas keseluruhan, laju perpindahan panas, number of heat transfer units (NTU), dan efektivitas. Hasilnya menunjukkan bahwa laju perpindahan panas dalam penukar panas berkisar dari 69,24 hingga 83,13 kW. Energi panas yang dihasilkan dalam eksperimen III lebih tinggi karena temperaturnya paling tinggi, ini berbeda dengan efektivitas dan NTU-nya karena masingmasing memiliki nilai terendah (0,77 dan 2,55). Perbedaan tekanan total yang terjadi dalam penukar panas tersebut adalah 366,8 Pa. Nilai ini jauh lebih kecil dibandingkan tekanan statik kipas yang dipakai yaitu 78 mm H2O.Kata kunci: efektivitas, konsumsi kerosen, laju perpindahan panas, perbedaan tekanan, shell and tube AbstractThis study aimed to determine the performance of the heat exchanger shell and tube type temperature-controlled outlet. Heat exchangers used in this study is the heat exchanger shell and tube types with kerosene fuel. The performance parameters analyzed are the consumption of kerosene, outlet temperature, overall heat transfer coefficient, heat transfer rate, the number of heat transfer units (NTU), and effectiveness. The result showed that the rate of heat transfer in the heat exchanger ranged from 69.24 to 83.13 kW. Heat energy produced in the experiment III was higher because its temperature is highest, this is different from its effectiveness and NTU since there are the lowest value (0.77 and 2.55) respectively. Total pressure drop that occured in the heat exchanger is 366.8 Pa. Furthermore, this value is smaller than the static pressure fan which had been installed and it was 78 mm H2O.

Catfish is health food which contains good nutritional values. Aceh people frequently consume this fish in fresh with complicated special recipe, so that the rate consumption of this fish is still low. Therefore, it is important to find the method for preserving this fish to improve its consumption. Liquid smoke can be used as one method to prepare the fish. The purpose of this study is to assess the quality of catfish under the treatments with and without soaking the fish in liquid smoke.Catfish was cleaned and washed, then it was dipped in solution with 2% salt for 30 min. Afterthat, catfish were air-dried for about 1 hour. About 200 ml of liquid smoke was diluted in 9800 ml water. After soaking in solution with 2% liquid smoke for 10min, catfish were dried by using a cabinet dryer which has three layers. The parameters observed were moisture content and sensory analysis. About 25 panelists had evaluated the samples for appearance, flavor, taste, texture, and color.The results showed that the combination process of smoking and drying might maintain the product quality. The moisture contents of all products were still in appropriate amount as required by the Indonesian Standar (SNI).  According to organoleptic test, the smoke-dried catfish was preferred by panelist than the unsmoked-dried one. Therefore, soaking catfish in liquid smoke can be used to improve the taste of the fish. Further study is recommended to evaluate the shelf life of smoke-dried catfish.

Abstrak. Pemanfaatan energi panas buangan dari proses kondensasi asap cair belum banyak diaplikasikan, selama ini panas dibuang ke media air yang disirkulasikan. Penelitian ini bertujuan untuk mendesain dan menguji fungsional unit penghasil asap cair yang terintegrasi dengan pengering kabinet. Penelitian ini terdiri dari tiga tahapan yaitu perancangan (desain struktural dan fungsional), pabrikasi, dan uji fungsional hasil rancangan. Perekayasaan ini menghasilkan unit penghasil asap cair yang terintegrasi dengan pengering kabinet. Alat ini terdiri dari empat komponen utama yaitu tabung pirolisator, pipa penukar panas, pengering kabinet serta kondensor. Berdasarkan uji fungsional, alat ini telah dapat menghasilkan asap cair dengan volume berkisar antara 2300 – 3182 ml selama 5 jam proses pembakaran tempurung kelapa. Wadah 1 merupakan wadah yang paling banyak menampung asap cair dibandingkan wadah 2, hal ini menunjukan proses kondensasi lebih banyak terjadi pada pipa penukar panas Design and Construction of Machine for Liquid Smoke Production Integrated with Cabinet DryerAbstract. Utilization of released heat energy from the condensation of liquid smoke has not been widely applied. Recently, the heat generated from the process was discharged and circulated into water as a cooling media. This research aimed to design and test a functional of liquid unit integrated with a dryer cabinet. The study consisted of three steps including design (structural and functional design), manufacturing, and testing a functional of results designed. This research and development produced liquid smoke integrated with the dryer cabinet. This machine consisted of four main components including tube of pirolisator, heat exchanger, condenser and dryer cabinet. Based on the functional test, this machine had been able to produce liquid smoke, ranged from 2300 to 3182 ml for 5 hours burning process of coconut shells. The first container was a container that received much more liquid smoke compared with the second container 2.  This research revealed that condensation process occurs more frequently in the heat exchanger pipe.