ABSTRAK Indonesia memiliki potensi panas bumi yang besar. Daerah potensi panas bumi seperti di daerah Cimanggu, Provinsi Jawa Barat umumnya memiliki sumber air panas. Sumber air panas selain dimanfaatkan untuk pariwisata, dapat pula dimanfaatkan sebagai pembangkit tenaga listrik. Temperatur sumber air panas yang relatif rendah antara 60° - 90°C membutuhkan teknologi khusus agar dapat dimanfaatkan sebagai pembangkit tenaga listrik. Siklus Kalina KCS34 merupakan siklus yang memanfaatkan campuran ammonia-air sebagai fluida kerja untuk menyerap energi kalor dari sumber panas bertemperatur rendah karena sifat dari campuran ammonia-air yang memiliki titik didih yang rendah. Fraksi campuran ammonia-air dan tekanan kondensor dapat mempengaruhi daya turbin dan efisiensi dari siklus Kalina KCS34. Simulasi optimasi fraksi campuran ammonia-air dan tekanan kondensor dilakukan untuk mengetahui besarnya fraksi campuran ammonia-air dan tekanan kondensor yang sesuai untuk digunakan sebagai pembangkit tenaga listrik di daerah Cimanngu, Provinsi Jawa Barat. Berdasarkan hasil simulasi, untuk mendapatkan kondisi pembangkit yang optimum di lokasi tersebut diperlukan fraksi campuran ammonia-air sebesar 87% dengan tekanan kondensor 7.6 bar sehingga akan dihasilkan daya turbin sebesar 73.57 kW dengan efisiensi sistem 14.85%. Kata kunci: Siklus Kalina, optimasi, campuran ammonia-air.  ABSTRACT Indonesia have a large potential of geothermal resources. Geothermal resource area such as Cimanggu area, West Java Province has natural hot spring resources. These natural hot spring resource can be utilized for eco tourism and electric power plant. Natural hot spring have relatively low water temperature between 60° - 90°C and it need special technology to be utilized as electric power plant. Kalina cycle KCS34 is a cycle that utilize ammonia-water mixture to absorb energy from low temperature natural hot spring source because of the properties of ammonia-water mixture that can boiled at low temperature. The fraction of ammonia-water mixture and the condensor pressure of the Kalina cycle KCS34 can affect the turbine output power and system efficiency. Optimization simulation was held to discover the required fraction of ammonia-water mixture and condenser pressure that suitable for generating electricity on Cimanggu area, West Java Province. According to the simulation results, the optimum fraction of ammonia-water mixture is 87% and the condensor pressure at 7.6 bar which will generate 73.57 kW of turbine power with 14.85% system efficiency. Keywords: Kalina cycle, optimization, ammonia-water mixture.

The use of synthetic coatings as Food Additives consumed in the long term can damage human health. These horrible effects have paved the way for the development of edible films and natural edible coatings. One of the edible film ingredients is scorched rice which can be used as a coating in fruit preservation. However, the use of this edible film on food ingredients has some problems, especially its mechanical properties which tend to be fragile (not flexible). This article examines the mechanical characteristics of scorched rice with variations in the concentration of glycerol and carrageenan. Based on these results, it was concluded that the higher the volume of glycerol used, the percent elongation increased. The greatest elongation was obtained in the ratio of 3 g of carrageenan with 8 ml of glycerol. However, the addition of glycerol volume causes the biodegradable plastic to tear more easily. The greatest tensile strength value was obtained with a ratio of 5 g of carrageenan and 4 ml of glycerol. The edible film can prevent the spoilage of apples tested for 10 days.