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The Southeast Sumatra block produces oil and gas. Natural gas production of 15,300 MSCF is used as fuel for turbine generators to generate 38 MW of electrical energy, while the rest is used as business products. The application of the solar-wind system can reduce the load on the turbine generator so that gas fuel consumption is also reduced. Five platforms have areas that can be utilized for a solar-wind system. This study aims to determine the amount of gas fuel consumption that can be reduced by the solar-wind system application. The method is simulation using the HOMER software to determine the amount of electrical energy that can be supplied and the costs required by the solar-wind system. The components used are found in the HOMER software and on the market. The simulation results show that the off-grid solar-wind system can provide electricity supply of 50,235 kWh per year and reduce gas fuel consumption by 20,094 MSCF per year. The on-grid solar-wind system can provide electricity supply of up to 81,230 kWh per year and reducing the use of gas fuel by 32,492 MSCF per year. The off-grid solar-wind system will increase gas sales by $132,620 per year with NPV>0 and ROI 21%, while the on-grid system will increase gas sales by $214,447 per year with NPV>0 and ROI 57%. Both models of solar-wind systems have positive economic values ​​so that they are feasible to implement

Solid Waste Oil Palm Empty Fruit Bunches have high nutrients, which significantly determine oil palm growth rate and production. Each nutrient has its role and can show specific symptoms in plants if their availability in the soil is very lacking. Dry oil palm land and the difficulty of procuring chemical fertilizers for the community that owns oil palm plantations in Simardona Village are expected to be overcome by the use of OPEFB. Utilization of Oil Palm Empty Bunches as Mulch was done manually in 4 research scenarios. Scenario 1 uses 2 kg of chemical fertilizers plus 250 kg of OPEFB, scenario 2 uses 2 kg of chemical fertilizers plus 300 kg of OPEFB, scenario 3 uses 2 kg of chemical fertilizers plus 350 kg of OPEFB, and scenario 4 uses 2 kg of chemical fertilizers plus 400 kg of OPEFB.The results obtained are that the humidity or moisture has increased from a value of 1 to 4. Therefore, it can be seen that the effect obtained from the use of more OPEFB makes the humidity higher. The calculation of the total cost of using OPOPEFB as mulch is obtained from the sum of the price of chemical fertilizers, the price of OPOPEFB, and workers' wages. The total cost after utilization of TKKS is IDR854,000.00. The total cost before using TKKS was IDR441,600,000. The difference in costs before and after the utilization of TKKS is IDR412,400.00, an increase in costs of 48%. The cost of using TKKS is higher than before using TKKS. The total harvest obtained before the use of OPEFB is 2,000 kg or IDR4,900,000. Meanwhile, after using OPEFB, the total yield obtained was 2,700 kg or IDR6,615,000. Production income increased by 26%.

Porous carbon from biomass has a great potential to be developed. Biomass as a resource is renewable, abundantly available, and cheap. One application of porous carbon is as an electrode material of supercapacitor due to its advantageous pore properties such as high specific surface area and pore volume. This research prepared porous carbon material from pineapple peel waste and tested it as a supercapacitor electrode. The research steps were material preparation, conversion of pineapple peel to porous carbon, and characterization, including material characterization and electrochemical characterizations. Pineapple peel (under 80 mesh size) was pre-carbonized by hydrothermal method at 1900C for 2 hours under a subcritical condition. After that, biochar was pyrolyzed at 9000C and activated using CO2/N2 (KB-900-50). As a reference, biochar was also pyrolyzed under a nitrogen atmosphere at 9000C without activation (KB-900). Produced porous carbon was characterized (i) pore structures, e.g., specific surface area, average pore diameter, and total pore volume using N2-sorption analysis, and (ii) electrochemical performance, e.g., cyclic voltammetry and galvanostatic method using 1 M H2SO4 electrolyte solution. The result showed that the activation process effectively increased the porosity of porous carbon. Material (KB-900-50) possesses a high surface area of 648 m2/g and a high capacitance value of 78 F/g.

The weakness of an outdoor solar water heater (SWH) experiments is the difficulty in determining its thermal behavior. The fluctuation of solar radiation intensity causes the supply of energy received by SWH also fluctuate. The result is that the thermal behavior of the SWH cannot be known for specific parameters. This paper aims to investigate the thermal behavior of an active type SWH containing paraffin wax using the constant heat flux method. A phase change material (PCM) inserted into the capsule. The capsules were arranged in a tank to form a heat exchanger (HE). The thermocouples were mounted both on the waterside and the PCM side. The solar simulator installed on the top of the collector, and the SHW system placed indoors. The heat flux and water flow were set at 1000 W/m2 and 2 LPM, respectively. The temperatures of water and PCM for 143 minutes charging recorded. The data obtained were used to analyze the thermal behavior of water and PCM. The results showed that the average heating rate of water and PCM was 0.227 °C/min and 0.205 °C/min, respectively. The value of this adjacent average heating rate shows that HE has functioned well in removing heat energy from water. The accumulated thermal energy produced was 13.08 MJ. Indoor experiments can reveal the thermal behavior of the SWH-PCM systems.

A performance analysis based on exergetic performance coefficient (EPC) criterion was carried out for a dual-evaporator vapor compression refrigeration system. The influence of the condensing and evaporating temperature on the EPC, the coefficient of performance (COP), the second law efficiency and the destruction of exergy will be presented. It is found that the evaporating and condensing temperatures have strong effects on EPC in the system. Condensing temperature increases will decrease EPC, COP, and second law efficiency, while evaporating temperature increases will increase the EPC, COP, and second law efficiency. The EPC increases and the total exergy destruction decreases with decreasing temperature difference between the evaporator and refrigerated space and between the condenser and ambient temperature. The EPC can be used for selection of optimal design parameters and the procedures given in this paper for exergy analysis of a dual evaporator vapor compression refrigeration systems has been applied to actual systems.A performance analysis based on exergetic performance coefficient (EPC) criterion was carried out for a dual-evaporator vapor compression refrigeration system. The influence of the condensing and evaporating temperature on the EPC, the coefficient of performance (COP), the second law efficiency and the destruction of exergy will be presented. It is found that the evaporating and condensing temperatures have strong effects on EPC in the system. Condensing temperature increases will decrease EPC, COP, and second law efficiency, while evaporating temperature increases will increase the EPC, COP, and second law efficiency. The EPC increases and the total exergy destruction decreases with decreasing temperature difference between the evaporator and refrigerated space and between the condenser and ambient temperature. The EPC can be used for selection of optimal design parameters and the procedures given in this paper for exergy analysis of a dual evaporator vapor compression refrigeration systems has been appl...

A large amount of disposed ash can cause severe environmental pollutions especially in large coal fired electric powerplants. One of many methods for reducing its negative impacts is to utilize the waste to produce ALWA (artificial leight weight aggregates) which is required to make light concrete for building constructions. However thorough researches have to be conducted first to find out the proper process conditions for ALWA production from fly ash and bottom ash of Indonesian coals. The investigated process conditions are the mixture composition of required raw, materials and the sintering conditions (e.g. temperature. duration, etc.). Moreover, an equipment to mix raw materials homogeneously and to produce other shapes of ALWA, which may be better than the existing shapes, must be built during the research. The last objective of the research is characterizing the physical and mechanical properties of the ALWA and some prototypes of light concrete made from the ALWA. It is expected that both the ALWA and the light concrete can satisfy the quality and specifications determined be existing standards. ABSTRAKAbu yang terbuang dalam jumlah besar dapat menyebabkan polusi lingkunga, terutama abu yang berasal dari batubara yang terbakar untuk keperluan pembangkit tenaga listrik. Salah satu dari berbagai metode untuk meredusir/mengurangi dampak negative adalah dengan menggunakan limbah untuk memproduksi ALWA (artificial light weight aggregates) yang diperlukan untuk membuat beton ringan untuk konstruksi bangunan. Tetapi, riset secara menyeluruh harus dilakukan untuk menemukan kondisi proses yang benar untuk produksi ALWA yang berasal dari abu yang berterbangan dan abu yang ada di dasar yang berasal dari batubara Indonesia. Kondisi penelitian proses adalah campuran dari komposisi material mentah yang diperlukan serta kondisi sintering (suhu, durasi dsb). Tambahan lagi, suatu peralatan untuk mencampur material mentah secara homogin dan untuk memproduksi berbagai bentuk ALWA, yang mungkin lebih baik dari bentuk yang sekarang ini ada, harus dibuat selama penelitian. Tujuan terakhir bentuk ALWA, yang mungkin lebih baik dari bentuk yang sekarang ini ada, harus dibuat selama penelitian. Tujuan terakhir penelitian ini adalah menghidentifikasi karakter dari fisik dan mekanik ALWA dan prototype beton ringan yang dibuat dari ALWA. Diharapkan bahwa ALWA dan beton ringan dapat memnuhi kualitas dan spesifikasi dari standard yang ada., A large amount of disposed ash can cause severe environmental pollutions especially in large coal fired electric powerplants. One of many methods for reducing its negative impacts is to utilize the waste to produce ALWA (artificial leight weight aggregates) which is required to make light concrete for building constructions. However thorough researches have to be conducted first to find out the proper process conditions for ALWA production from fly ash and bottom ash of Indonesian coals. The investigated process conditions are the mixture composition of required raw, materials and the sintering conditions (e.g. temperature. duration, etc.). Moreover, an equipment to mix raw materials homogeneously and to produce other shapes of ALWA, which may be better than the existing shapes, must be built during the research. The last objective of the research is characterizing the physical and mechanical properties of the ALWA and some prototypes of light concrete made from the ALWA. It is expected that both the ALWA and the light concrete can satisfy the quality and specifications determined be existing standards.ABSTRAKAbu yang terbuang dalam jumlah besar dapat menyebabkan polusi lingkunga, terutama abu yang berasal dari batubara yang terbakar untuk keperluan pembangkit tenaga listrik. Salah satu dari berbagai metode untuk meredusir/mengurangi dampak negative adalah dengan menggunakan limbah untuk memproduksi ALWA (artificial light weight aggregates) yang diperlukan untuk membuat beton ringan untuk konstruksi bangunan. Tetapi, riset secara menyeluruh harus dilakukan untuk menemukan kondisi proses yang benar untuk produksi ALWA yang berasal dari abu yang berterbangan dan abu yang ada di dasar yang berasal dari batubara Indonesia. Kondisi penelitian proses adalah campuran dari komposisi material mentah yang diperlukan serta kondisi sintering (suhu, durasi dsb). Tambahan lagi, suatu peralatan untuk mencampur material mentah secara homogin dan untuk memproduksi berbagai bentuk ALWA, yang mungkin lebih baik dari bentuk yang sekarang ini ada, harus dibuat selama penelitian. Tujuan terakhir bentuk ALWA, yang mungkin lebih baik dari bentuk yang sekarang ini ada, harus dibuat selama penelitian. Tujuan terakhir penelitian ini adalah menghidentifikasi karakter dari fisik dan mekanik ALWA dan prototype beton ringan yang dibuat dari ALWA. Diharapkan bahwa ALWA dan beton ringan dapat memnuhi kualitas dan spesifikasi dari standard yang ada.

Aceh Tamiang is the province o f Aceh. The use of electrical energy is still not resolved in this case because of the lack of appropriate policies that can be taken because there is still no research how the amount of electrical energy consumption in Aceh Tamiang. the research method used is a model based approach to End Use of data population and households, the data GDP at constant prices, and consumption of electrical energy. All data is sourced from related agencies such as Bappeda Aceh Tamiang Data PLN Kuala Simpang branch. Forecasting electric energy consumption in Aceh on five sectors is the year 2013 was 48.8 GWh, while, in 2030 total energy consumption reached 76.5 GWh, this is an increase of 63.7 percent. The household sector accounted for the largest increase in consumption compared with other sectors for each year.

Phase change material (PCM) dikenal memiliki densitas energi yang lebih tinggi dibandingkan dengan material penyimpan kalor sensibel. Oleh karena itu, PCM menarik diaplikasikan pada pemanas air tenaga surya (PATS) yang umumnya menggunakan air sebagai penyimpan energi termal. Penelitian terakhir untuk sistem PATS thermosyphon belum dapat mengidentifikasi perilaku termal PCM pada arah radial dan aksial. Selain itu, tidak diketahui temperatur PCM saat terjadi pelelehan karena sumber kalornya berfluktuasi. Penelitian ini bertujuan untuk menyelidiki perilaku termal proses pelelehan paraffin wax secara numerik di dalam pipa ganda konsentrik dengan sumber kalor yang konstan. Simulasi numerik dilakukan pada penyimpanan energi termal berbentuk pipa ganda konsentrik. Paraffin wax dimasukkan pada pipa bagian dalam sedangkan air sebagai heat transfer fluid (HTF) dialirkan di bagian annulus . Termokopel dipasang di beberapa tempat baik sisi HTF maupun sisi PCM. Software yang dipakai adalah ANSYS FLUENT 17. Proses simulasi dilakukan dengan membuat meshing , menginput persamaan dan kondisi batasnya, setting penghitungan jumlah iterasi serta batas konvergensi dan dilanjutkan dengan pengambilan data temperatur selama proses charging . Simulasi menggunakan variasi temperatur HTF input dan laju aliran massanya. Hasil simulasi menunjukkan bahwa proses pelelehan PCM tidak terjadi secara isotermal. Transfer kalor ke PCM saat awal charging terjadi secara konduksi dan berlangsung cepat yang diakibatkan oleh besarnya gradien temperatur di arah radial pada fasa padat. Pembentukan fraksi cairan di sepanjang sisi luar PCM terjadi sejak awal proses charging . Bilangan Stefan mempunyai pengaruh yang besar terhadap proses pelelehan PCM.