Analisis Eksergi Pengeringan Irisan Temulawak

Temulawak (Curcuma xanthorrhiza Roxb.) merupakan tanaman obat yang simplisianya digunakan sebagai bahan baku pembuatan jamu atau obat tradisional. Pengeringan merupakan proses utama dalam memproduksi simplisia. Untuk menganalisis efisiensi energi suatu proses pengeringan umumnya digunakan hukum termodinamika pertama yang menjelaskan tentang prinsip kekekalan energi. Akan tetapi teori ini mempunyai keterbatasan dalam mengukur penurunan kualitas energi. Untuk mengetahui apakah energi yang digunakan pada proses pengeringan sudah digunakan secara optimal dari sisi kualitas, digunakan hukum termodinamika kedua atau yang dikenal dengan analisis eksergi. Tujuan penelitian ini adalah menentukan efisiensi proses pengeringan lapisan tipis irisan temulawak dengan metode analisis energi dan eksergi. Dalam studi ini, metode analisis energi dan eksergi berdasarkan hukum termodinamika pertama dan kedua telah digunakan untuk menghitung rasio penggunaan energi dan besaran eksergi yang musnah (exergy loss). sehingga efisiensi proses pengeringan irisan temulawak dapat ditentukan secara akurat. Hasil penelitian menunjukkan bahwa kondisi proses pengeringan mempengaruhi rasio penggunaan energi dan efisiensi eksergi pengeringan. Semakin tinggi suhu dan RH pengeringan maka rasio penggunaan energi semakin rendah dan efisiensi eksergi semakin tinggi. Efisiensi eksergi pengeringan temulawak bervariasi antara 96,5%-100% untuk selang suhu 50 oC hingga 70 oC pada RH 40% serta 82,3% - 100% untuk selang RH 20% hingga 40% pada suhu 50 oC

Experimental and Theoritical Analysis of Thermal Properties in Zephyr Bamboo Tali (Gigantochloa Apus Kurz)

Specific heat, thermal conductivity and thermal diffusivity of Bamboo panel are USAble to support the Programming of Design and Planning in the Structure of the Agricultural Building Construction. The Specific heat of Bamboo's fiber, sheet and panel using the method of mixtures varied from 1.585-2.789 J/gr oC, with a mean value of 2.227 J/gr oC in the temperature difference range of 9 ± 0.1oC . It was found it will increase linearly with an increase in the sample temperature. Thermal conductivity values of Bamboo's fiber based on the transient line heat source technique varied from 0.1035 x 10-3-0.1322 x10-3 J/ cm2 sec oC in the sample temperature 22 to 30 oC on thermal diffusivity of bamboo fiber in 22-30 oC was found to be 0.0823 x 10-3J/cm secoC. The sorption Isotherm and the water activity in the bamboo's panel is depend on the chemical composition, glue laminated, additive and the porosity. There are related with the absorbing of the water into the bounded water and the diffusivity of the water in and out the panel. The moisture equilibrium range are 7.89 to 19.22 percent in the control of the circumstances and 11 to 75 % of the environment.relative humidity

Kajian Eksergi pada Mesin Pendingin Adsorpsi Menggunakan Pasangan Silikagel-Metanol

Sistem pendingin adsorpsi merupakan salah satu dari sistem pendingin yang ramah lingkungan, dimana dalam ope-rasinya sistem ini dapat dibangkitkan menggunakan sumber energi terbarukan seperti biomassa ataupun sinar surya. Sistem pendingin adsorpsi yang digunakan dalam percobaan ini menggunakan pasangan silika gel-metanol sebagai absorben dan refrigeran. Tujuan dari penelitian ini adalah mendapatkan kinerja mesin pendingin adsorpsi intermit- ten pasangan silikagel-metanol dan melakukan analisis eksergi pada mesin pendingin adsorpsi intermitten pasangan silikagel­metanol. Metode penelitian diawali dengan pengujian terhadap kebocoran pada semua komponen di da- lam sistem pendingin adsorpsi dan dilanjutkan dengan pengujian sistem pendingin adsorpsi menggunakan pasangan silikagel­metanol. Suhu tiap komponen yaitu generator, kondensor, evaporator dan pipa­pipa masukan dan keluaran diukur dengan menggunakan termokopel tipe C­C yang dihubungan dengan alat perekam suhu. Sedangkan untuk analisis eksergi diawali dengan perancangan model pada masing­masing komponen dalam sistem pendingin adsorpsi intermitten. Hasil percobaan menunjukkan nilai kehilangan eksergi yang diperoleh untuk tiap proses dalam sistem pendingin adsorpsi. Nilai kerugian eksergi menggambarkan ketidak efektifan proses transfer energi dalam sistem pendinginan adsorpsi. Rincian hasil yang dicapai dari perhitungan dengan analisis eksergi memberikan data pada generator desorpsi kehilangan eksergi (exergy destroy) sebesar 35.33 Watt (90.57 %). Kondensor memberikan nilai sebesar 0.20 Watt (0.51 %). Evaporator memberikan nilai sebesar 0.07 Watt (0.18 %) dan pada generator adsorpsi memberikan nilai sebesar 3.51 %

The Effect of Freezing Rate and Surface Temperature on Freeze Drying Time of Minched Beef

Freeze drying of food materials is a time and energy consuming process, hence a high cost process. The drying rate is limited by heat and mass transfer process within the dried portion of the product. In order to improve the freeze drying performance, it is important to know parameters which affect the drying characteristics of each spesific food material, in regard to the drying time and the energy consumption. The objective of this experiment was to study the freeze drying characteristic of miched beef especially the effect of freezing rate and surface temperature of the material to the drying time. The study was conducted with freezing rate at 7.71 cmhours and 1.94 cmhours which are classified into fast and slow freezing rate, while the surface temperature of the material was controlled at 40 OC, 35 OC, and 30 OC. The experimental results confirmed that the faster freezing rate then the longest drying time, while the higher surface temperature give a shorter drying time of miched beef. It is important to determine the optimal freezing rate and surface temperature from the view point of energy consumption

Freeze Drying of Food Materials is a Time and Energy Consuming Process, Hence a High Cost Process. the Drying Rate is Limited by Heat and Mass Transfer Process Within the Dried Portion of the Product. in Order to Improve the Freeze Drying Performance, IT is Important to Know Parameters Which Affect the Drying Characteristics of Each Spesific Food Material, in Regard to the Drying Time and the Energy Consumption. the Objective of This Experiment Was to Study the Freeze Drying Characteristic of M

Freeze drying of food materials is a time and energy consuming process, hence a high cost process. The drying rate is limited by heat and mass transfer process within the dried portion of the product. In order to improve the freeze drying performance, it is important to know parameters which affect the drying characteristics of each spesific food material, in regard to the drying time and the energy consumption. The objective of this experiment was to study the freeze drying characteristic of miched beef especially the effect of freezing rate and surface temperature of the material to the drying time. The study was conducted with freezing rate at 7.71 cmhours and 1.94 cmhours which are classified into fast and slow freezing rate, while the surface temperature of the material was controlled at 40 OC, 35 OC, and 30 OC. The experimental results confirmed that the faster freezing rate then the longest drying time, while the higher surface temperature give a shorter drying time of miched beef. It is important to determine the optimal freezing rate and surface temperature from the view point of energy consumption

Design and Performance Test of Measuring Apparatus of Dielectric Properties Using Q-Meter Method

Dielectric heating has received a lot of attention recently. Microwave heating, however, has the problem of noticeable hot and cold spots within a food. Radio frequency (RF) has the potential to overcome this problem because of its longer wavelength and greater penetration depth, which would lead to more uniform distribution of the electric field and thus a more uniform temperature distribution. The dielectric properties are the measure of a sample's response to an electromagnetic field, which vary significantly with frequency, temperature, moisture, and salt content. The potential of a medium to respond to dielectric heating can be characterized by its dielectric properties, which can be strong functions of frequency and temperature. This experiment is aimed to design and test the performance of a measurement apparatus for the dielectric properties, using the Q-meter method

Desain Dan Pengujian Kinerja Kompor Gasifikasi-pirolisis

This paper deals with the design and performance test of pyrolysis burning stoves that produce energy for cooking and biochar. The stove consists of two section chambers, namelycombustion chamber that produces activation heat for pyrolysis process and energy for cooking, andpyrolysis chamber that produces biochar and volatile matter (syngas and tar in gas form). Volatile matter product was introduced to the combustion chamber in addition to the biomass there and replaces biomass fuel gradually to produce energy for cooking and keeping the continuous pyrolysis process (autothermal). Methode used for performance test: direct observations/measurements and Water Boilling Test (WBT). Result of performance test: the autothermal process was going well until resulting a 100% biochar for most of the biomass used. Thermal efficiency of the stove was 11.3% (before pyrolysis) and 14.72% (after pyrolysis), excluding heat to produce biochar. Time needed to boil a 5 L water was 12 minutes before pyrolysis and 6 minutes after pyrolysis. Output power ranges from 9.60 kW to 23.16 kW. The maximum temperature reached 868 °C at the pan and 860oC in combustion chamber.Input biomass capacity depending on the type of feedstock ranging from 1200 - 3000 g/process, resulting in 507-900 g biochar/process, to give biochar ratio to raw materials from 23.0% to 44.8%. All maximum conditions occurs when volatilematters produced from pyrolysis process were burned, which showed that burning volatile matters is better than burning solid biomass directly.The amount of biochar produced by this stove was three times higher compared to anila stove, with less of smoke during the biochar production