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Abstrak :
Energi listrik merupakan salah satu infrastruktur yang menyangkut hajat hidup orang banyak, oleh karena itu sudah seharusnya eketersediaan energi listrik terjamin dengan jumlah yang cukup dengan mutu yang baik dan harga yang wajar. Pertumbuhan perekonomian nasional menyebabkan konsumsi listrik setiap tahunnya terus meningkat. Dengan meningkatnya kebutuhan akan energi dan maraknya isu mengenai permasalahan lingkungan membuat para ahli terus mengembangkan teknologi yang tepat agar dapat mengatasi kedua masalah tersebut. Sistem PLTP siklus biner merupakan salah satu teknologi pembangkit yang sangat efektif untuk diterapkan dalam pemanfaatan energi panas bumi skala kecil enthalpy rendah sampai menengah dengan menggunakan fluida kerja yang memiliki titik didih lebih rendah daripada air, oleh karena itu maka pada tesis ini dilakukan suatu pemodelan sistem PLTP siklus biner dengan memanfaatkan waste brine dengan temperatur 180 0C pada wellpad 4 PLTP Dieng. Pemodelan dilakukan dengan menggunakan software Matlab dan REFPROP, kemudian dilakukan optimasi terhadap sistem dimana exergy destruction total dan total annual cost dipilih sebagai fungsi objektif. Adapun optimasi dilakukan dengan menggunakan multi objective genetic algorithm. Berdasarkan simulasi diketahui bahwa efesiensi exergi dan nilai ekonomis dari sistem PLTP siklus biner yang optimal adalah pada temperatur evaporasi sebesar 163,3 oC, temperatur brine keluar preheater sebesar 130 0C, temperatur air pendingin keluar kondenser sebesar 35,4 0C, tekanan kerja fluida kerja keluar pompa sebesar 3859 kPa dengan campuran refrigeran 86 R601 dan 14 R744 menghasilkan daya turbin sebesar 119,8 kW nilai exergy destruction total 742,4 kW dengan efesiensi exergy sebesar 48,8 dan total annual cost sebesar 36.723 US dollar.Kata kunci : PLTP siklus biner, efesiensi exergi, exergy destruction , cost, genetic algorithm. ......Electrical energy is one of the important part of human life, so the provision of electrical energy must be able to guarantee the availability of sufficient quantity, reasonable price and good quality. Indonesia rsquo s electricity consumption every year continues to increase in line with the increase of national economic growth. The increasing demand on energy and environmental issues make the experts to develop the right technology in order to face both issues. PLTP binary cycle is a highly effective generating technology to be applied in the utilization of small scale enthalpy low to medium geothermal energy by using a working fluid that has a lower boiling point than water, hence in this thesis a PLTP binary system model was performed using waste brine with temperature of 180oC at wellpad 4 in PLTP Dieng. Modeling has been done by using Matlab and REFPROP software, then optimization procedure has been conducted to the system where total exergy destruction and total annual cost are chosen as the objective function. In addition, environmental aspects are also considered in this modeling where natural environmentally friendly working fluids are used. The optimization is done by using multi objective genetic algorithm. Based on the simulation it is known that the exergy efficiency and economic value of the optimal binary cycle of PLTP system has an optimum condition at the evaporation temperature of 163.3 oC, the brine temperature out the preheater of 130 oC, the condenser coolant outlet temperature of 35.4 oC, the outlet pump pressure at 3859 kPa with composition of refrigeran mixture 86 R601 and 14 R744, turbine power of 119.8 kW, total exergy destruction of 742.4 kW with exergy efficiency of 48.8 , and total annual cost about 36.723 US dollars.

Abstrak :
Pengeringan beku diakui sebagai metode pengeringan terbaik tetapi sangat intensif energi yang disebabkan dua hal yaitu proses pembekuan pada tekanan yang berbeda dengan pengeringan dan perambatan panas yang lambat selama sublimasi. Proses pembekuan dalam hal ini dihasilkan dari perubahan tekanan dalam suatu tabung vakum yang mengacu pada diagram fasa air dimana seiring dengan penurunan tekanan maka akan terjadi penurunan temperatur dalam suatu ruang sehingga jika suatu produk yang dijadikan sebagai eksperimen diletakkan didalamnya maka akan terjadi proses pembekukan. Pada penelitian ini akan dilakukan variasi temperatur coldtrap untuk melihat kemampuan evaporator menangkap uap hasil sublimasi selama proses perubahan fase material, juga analisa potensi energi, dan exergy destruction pada sistem refrijerasi sehingga dapat dilakukan penghematan energi pada pengering beku vakum.

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Freeze-drying method of drying is recognized as the best but it is very energy intensive due to two things namely the freezing process at different pressures by drying and heat propagation is slow during the sublimation. The freezing process in this case resulting from changes in pressure within a vacuum tube which refers to the phase diagram of water which along with the decrease of pressure there will be a decrease in temperature in a room so that if a product is used as the experiment is placed in it there will be a process of freeze. In this study the temperature variation will be conducted to identify the capacity evaporator coldtrap capture vapors during the sublimation process of phase change material, as well as analysis of the potential energy, and exergy destruction in the system so it can be done refrijerasi energy savings in a vacuum freeze dryer.

Abstrak :
The performance of a 20 MW gas turbine power plant was described by using the exergy analysis and data from the plant?s record books. The first and second laws of thermodynamics, as well as the mass and energy conservation law, were applied in each of the components. The results show that more exergy destruction occured in the combustion chamber up to 71.03% or 21.98 MW. Meanwhile, the lowest exergy occured in the compressor at 12.33% or 3.15 MW. Thermal efficiency of the gas turbine power plant, according to the first law, was 33.77%, and exergy efficiency was 32.25%.

Abstrak :
The increasing demand for energy and the current environmental issues are motivating experts to develop appropriate technology to face both problems. The binary cycle system is a highly effective generating technology which can be applied in the utilization of small-scale geothermal energy by using a working fluid that has a lower boiling point than water. In this paper, a geothermal power plant binary cycle system model was tested by using waste brine at a temperature of 180oC at well pad 4 of the Dieng geothermal power plant. In the optimization procedure, total exergy destruction and total annual cost are chosen as the objective functions. Optimization is made by using a multi objective genetic algorithm. Based on the simulation, it is known that the exergy efficiency and economic value of the optimal binary cycle of the geothermal power plant system has optimum conditions at an evaporation temperature of 163.3oC, a brine temperature in the preheater outlet of 130oC, and a water cooling temperature at condenser outlet of 35.4oC. The working fluid pressure at pump outlet is 3859 kPa with the composition of the working fluid mixture being 86% R601 and 14% R744, resulting in turbine power of 119.8 kW, total exergy destruction of 742.4 kW, and a total annual cost of 36,723 US dollars. These results indicate that, by setting the above operating conditions, the system can achieve optimum efficiency, as indicated by the minimum values of both exergy destruction and total annual cost.

Abstrak :
The performance of a 20 MW gas turbine power plant was described by using the exergy analysis and data from the plant’s record books. The first and second laws of thermodynamics, as well as the mass and energy conservation law, were applied in each of the components. The results show that more exergy destruction occured in the combustion chamber up to 71.03% or 21.98 MW. Meanwhile, the lowest exergy occured in the compressor at 12.33% or 3.15 MW. Thermal efficiency of the gas turbine power plant, according to the first law, was 33.77%, and exergy efficiency was 32.25%.

Abstrak :
Dengan permintaan hidrogen yang tinggi di masa depan, pemanfaatan energi dingin tampaknya menjadi solusi alternatif untuk meningkatkan rantai ekonomi hidrogen dengan memaksimalkan pemanfaatan limbah energi dingin selama regasifikasi. Suhu rendah hidrogen cair (-253℃ pada 1 atm) akan memberikan beragam aplikasi yang dapat diimplementasikan. Makalah ini mengusulkan pembangkit daya dan unit pemisahan udara sebagai proses integrasi dari regasifikasi hidrogen cair. Untuk mencapai desain proses terbaik, pemilihan proses dibuat dengan mempertimbangkan tingginya pembangkitan daya dan rendahnya kerusakan eksergi. Desain proses terpilih akan diintegrasikan dengan unit pemisahan udara dengan 4 skenario laju alir dan dioptimasi untuk mendapatkan kondisi ideal dengan maksimal energi listrik hasil dan kerusakan eksergi yang minimum. Solusi ideal setiap scenario akan dievaluasi keekonomiannya. Dari hasil pemilihan proses, cascade rankine cycle mampu memulihkan energi pencairan hidrogen hingga 11,46 % dan menghasilkan kerusakan eksergi yang paling minim. Cascade rankine cycle kemudian diintegrasikan dengan unit pemisahan udara dan dioptimasi. Dari hasil simulasi, semakin tinggi laju alir udara akan menghasilkan energi listrik yang semakin rendah tetapi mampu mengurangi kerusakan eksergi hingga 1700 kW. Dari hasil perhitungan, skenario D, dengan laju alir 12000 kg/jam mampu memberikan internal rate of return paling tinggi (23,96%) dan payback period tersingkat 5,14 tahun dibanding dengan skenario lainnya.  ......With the future's high demand for hydrogen, utilizing cold energy appears to be an alternative solution to enhance the hydrogen economic chain by maximizing the use of cold energy waste during regasification. The low temperature of liquid hydrogen (-253℃ at 1 atm) offers various applicable implementations. This paper proposes integrating a power plant and an air separation unit with the liquid hydrogen regasification process. To achieve the optimal process design, the selection process considers both high power generation and low exergy destruction. The chosen process design will be integrated with the air separation unit under four different flow rate scenarios and optimized to obtain ideal conditions, maximizing electrical energy output and minimizing exergy destruction. The economic feasibility of the ideal solution for each scenario will be evaluated. Based on the process selection results, the cascade Rankine cycle can recover up to 11.46% of the hydrogen liquefaction energy and produce the least exergy destruction. The cascade Rankine cycle is then integrated with the air separation unit and optimized. Simulation results indicate that higher air flow rates yield lower electrical energy but can reduce exergy destruction by up to 1700 kW. According to economic calculations, scenario D, with a flow rate of 12,000 kg/hour, provides the highest internal rate of return (23.96%) and the shortest payback period of 5.14 years compared to other scenarios.

Abstrak :
Penelitian ini berfokus pada analisis dari konstruksi Pembangkit Listrik Tenaga Panas Bumi di Wilayah Kerja Panas Bumi WKP Tulehu. Salah satu sumur yang telah diuji di WKP Tulehu memproduksi fluida panas bumi dengan karakteristik low-medium enthalpy 130-165oC, low wellhead pressure 300-700 kPa, dan low mass flow rate 16,67-25 kg/s, dimana karakteristik tersebut sangat sesuai untuk diutilisasi dengan tipe binary power plant. Pembangkit listrik binary secara umum terdiri atas dua tipe Organic Rankine Cycle,yang menggunakan hidrokarbon sebagai fluida kerja, dan Kalina Cycle System, yang menggunakan campuran ammonia-air sebagai fluida kerja. Penelitian ini akan berfokus pada optimasi multiobjektif terhadap tipe pembangkit listrik binary yang paling sesuai dengan kondisi fluida panas bumi tersebut. Objektif yang akan dimasukkan dalam optimasi ini adalah Exergy Destruction dan Purchased Equipment Cost. Hasil optimasi tersebut kemudian akan digunakan sebagai basis untuk kalkulasi estimasi biaya proyek pembangkit listrik yang dicanangkan. Dengan begitu akan diperoleh tipe pembangkit listrik binary yang paling sesuai untuk digunakan di WKP tersebut. Simulasi dan optimasi dilakukan dengan menggunakan Matlab dan Engineering Equation Solver EES .

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This study focuses on simulation and optimization of the binary cycle power plant on Tulehu Geothermal Field. One of the tested well in the field produces geothermal fluid with characteristics such as low to medium temperature 130 165oC, low wellhead pressure 3-7 bar, and low mass flow rate 16,67 ndash 25 kg s, in which those characteristics are suitable for binary cycle power plant. Binary power plant can be categorized into two types, Organic Rankine Cycle, which uses hydrocarbon as its working fluid, and Rankine Cycle System, which uses ammonia water mixture as its working fluid. The study will mainly focuses on the optimization of the types of binary power plant with multiobjectives. Those objectives which will be included are Exergy Destruction and Purchased Equipment Cost. The results then will be used as basis for the estimation of the power plant project total cost. By using those method we will be able to find out the solution to which one of the types that have the best output for possible later use on the geothermal field. The simulation and optimization will be conducted by using Matlab and Engineering Equation Software EES.

Abstrak :
ABSTRAK PT. X telah melakukan studi kelayakan untuk rencana konversi dengan penggunaan 60 bahan bakar LNG pada salah satu lini kapalnya dengan trayek Tanjung Priok ndash; Makassar dengan memanfaatkan LNG Isotank tipe T75 ukuran 20 kaki 1 TEU , namun hanya terbatas pada kajian secara ekonomis. Untuk melakukan verifikasi bahwa rencana konversi ini benar-benar menguntungkan, penulis merasa perlu untuk melakukan kajian dari sudut pandang akademis, khususnya analisis karakteristik exergy fisik yakni laju perpindahan dan penghancuran exergy melalui dinding tangki akibat perpindahan kalor, serta karakteristik boil-off rate BOR dan boil-off gas BOG dari LNG yang dimuat, dilakukan dengan pendekatan closed system exergy balance dengan parameter kondisi pelayaran yang telah ditentukan, menggunakan persamaan empiris dari literatur dan model fisik dari tiga opsi tangki yang ditawarkan, dirancang dengan menggunakan COMSOL Multiphysics 5.1. Hasil analisis menunjukkan hubungan berkorelasi positif antara laju penghancuran exergy dengan nilai BOR dan BOG, bergantung pada nilai hambatan termal total Rtot akibat variasi material kulit dan insulasi dinding tangki yang mempengaruhi nilai kebocoran panas heat leak pada permukaan dalam dan luar dinding tangki. Skala kualitas disajikan di akhir pembahasan untuk meringkas parameter analisis yang bisa diukur dengan harga, yakni exergy cost dan biaya pengoperasian yang diperlukan forced vaporizer untuk mencapai BOR yang dibutuhkan.

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ABSTRACT
PT. X has conducted a feasibility study for conversion plans with the use of 60 LNG fuel on one of its ship lines with Tanjung Priok Makassar route using LNG Isotank type T75 size 20 feet 1 TEU , but only limited to economical study. To verify that the conversion plan is really profitable, analysis of physical exergy characteristics i.e. the rate of exergy transfer and destruction through tank wall due to heat transfer, boil off rate and boil off gas from stored LNG is conducted by a closed system exergy balance approach with specified shipping conditions parameters, using the empirical equations of the literature and physical model of the three tank options offered, designed using COMSOL Multiphysics 5.1. The results show a positive correlation between exergy destruction rate with BOR and BOG values, depending on the total thermal resistance value Rtot due to material variation of shell and insulation of tank wall affecting the value of heat leak on the inner and outer surface of the tank wall. Quality scale is presented to summarize the analysis parameters that can be measured by cost, i.e. the exergy cost and operating costs required by forced vaporizer to achieve the required BOR.

Abstrak :
Penelitian yang dilakukan berfokus pada simulasi perencanaan perancangan suatu sistem pembangkit listrik tenaga panas bumi bottoming unit pada wilayah kerja panas bumi dengan existing brine temperature berkisar antara 1720C hingga 1750C dengan brine mass flow rate senilai 264,6 kg/s perancangan tersebut dititikberatkan terhadap pertimbangan kinerja teknis dan aspek keekonomian pembangunan sistem pembangkit tersebut. Dalam keberlangsungannya penelitian berikut berupaya memberikan gambaran mengenai aplikasi sistem pembangkit binary cycle yang antara lain terbagi menjadi simulasi aplikasi organic rankine cycle simulasi aplikasi kalina cycle. ......This research is focused on simulating the design planning of a geothermal power plant system bottoming unit in the geothermal working area which existing brine temperature ranging from 1720C to 1750C with brine mass flow rate of 264.6 kg s. The design is focused on technical performance considerations compared economical aspects of the development of the generating system. In its continuation, the following research attempts to provide an overview of the application of binary cycle generation system, which is divided into organic rankine cycle application simulation and calina cycle application simulation.