The adsorption technology is becoming the more expected solution by today’s researchers for fix the energy and environmental issues. The main part of the cooling system adsorption is adsorbent and adsorbate. One of the most widely used adsorbents in research of adsorption technology is silica gel. A new silica gel-water adsorption chiller design was developed that composed of two sorption chambers with compact fin tube heat exchangers as adsorber, condenser, and evaporator. Energy, mass, and momentum conservation equations of the adsorption systems have been used for the CFD two and three dimensional models. The geometry of simulation is simply made within silica gel layer between two fins. The simulation is also implemented using a finite volume method through the CFD software Fluent. User defined functions are given to modify the energy, mass, and momentum conservation equations. The simulation of adsorption process is adjusted at unsteady condition. Adsorption and desorption processes are simulated with room temperature for cooling water inlet at temperature 305.15 °K, hot water inlet at temperature 353.15 °K, mass flow rate cooling water inlet at 0.3 kg/s and pressure 32 KPa. For the whole adsorbent bed area, the result shows that the highest absolute adsorption rate at the outer surface, while the lowest rate is at the center. After adsorption was finished, the condition is reversed. The highest absolute adsorption rate is achieved at center, while the lowest rate is achieved at the outer surface.
Abstract. In this paper, the combination of double-flash and binary cycles for Ulubelu geothermal power plant is proposed and optimized by using the Matlab software. This proposed system uses real data and properties of brine exploited from the Ulubelu geothermal well in Indonesia and four working fluid candidates, namely n-Pentane, R141b, R123 and R245fa are used in binary cycles. Optimization using a multi-objective genetic algorithm with an exergoenomic approach is applied to find out the proposed system performance from both thermodynamic and economic point of view. In the optimization procedure, the exergy efficiency and total specific cost of output power become objective functions while the first flash pressure, second flash pressure and Organic Rankine Cycle (ORC) turbine inlet temperature are selected as constraints. The system performance proposed in this paper is compared with the performance of the existing system. The results show that n-pentane is the best working fluid where multi-objective optimization indicates that the system can generate 63.54 MW of power with thermal and exergy efficiencies of 17.59% and 65.26% and specific cost of 1.7049 USD / GJ at the selected optimal design point. Compared to the existing system, there is a significant improvement in performance both from thermodynamic performance and economic performance.
Saat ini aplikasi mobile berbasis android telah banyak digunakan seiring semakin banyaknya perangkat smartphone android. Namun penyampaian informasi khususnya informasi bencana di majalengka masih saja belum tersampaikan dengan baik. Seiring dengan hal tersebut, maka dibutuhkan aplikasi pendukung untuk menyampaikan informasi bencana yang lengkap dan akurat. Penelitian ini dilakukan untuk perancangan aplikasi tanggap darurat bencana majalengka dengan konsep Geotagging berbasis android. Pengumpulan datanya menggunakan observasi, studi pustaka dan wawancara dengan metode pengembangan sistem menggunakan RUP, Kemudian data diimplementasi untuk dapat diaplikasikan pada aplikasi android. Pengimplementasian aplikasi android ini dirancang menggunakan bahasa pemrograman Java dengan aplikasi pendukung android studio versi 3. Pengujian aplikasi menggunakan blackbox, didapatlah aplikasi tanggap darurat bencana yang bisa digunakan untuk melaporkan kejadian bencana dari smartphone android dengan memberikan laporan bencana yang cukup jelas karena terdapat foto bencana, informasi mengenai titik lokasi bencana, keterangan bencana dan peta yang bisa diakses melalui google maps.
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