Showing papers by "Dominicus Danardono Dwi Prija Tjahjana published in 2021"

Analisis statistik performa turbin angin vertikal dengan slotted blades

Abstract: E nergi terbarukan merupakan energi alternatif yang bersih, bebas polusi, aman dan ketersediaanya tidak terbatas. Energi angin merupakan salah satu energi terbarukan. Pemanfaatan energi angin dilakukan dengan menggunakan turbin angin salah satunya savonius. Turbin savonius memiliki kekurangan pada nilai koefisien daya (Cp) yang rendah. Penambahan konfigurasi posisi dan lokasi slotted blades dapat meningkatkan nilai Cp. Untuk memaksimalkan desain turbin angin savonius maka perlu dicari faktor yang paling berpengaruh terhadap nilai Cp. Penelitian ini bertujuan untuk menganalisis signifikansi unjuk kerja turbin angin savonius dengan konfigurasi slotted blades secara statistik. Pengujian hipotesis dari dua faktor yang mempengaruhi nilai Cp dilakukan dengan menggunakan metode pengujian statistik Kolmogorov Smirnov Test, Normalitas test, analysis-of-variance (ANOVA) linier, one-way ANOVA menggunakan software SPSS 22. Hasilnya menunjukkan bahwa lokasi slotted blades berpengaruh secara signifikan terhadap nilai Cp (Sig. 0,000 kurang dari 0,05). Terdapat interaksi antara kedua variabel uji posisi*lebar (Sig. 0,000 kurang dari 0,05). Posisi slotted blades lebih berpengaruh signifikan terhadap nilai Cp karena nilai Sig. 0,000 lebih rendah dari lebar slotted blades 0,011

Performance of Crossflow Wind Turbines in In-line Configuration and Opposite Rotation Direction

Abstract: Wind energy sources must be investigated to produce electrical energy from a renewable source. Crossflow wind turbines are suitable for use because they have several advantages such as self-starting ability, low noise, and excellent stability. They have the potential to be applied as small wind turbines in urban districts because of their small maximum coefficient of power (Cp), which is 10% of that of other small wind turbines. To enhance the performance of crossflow wind turbines, we changed the turbine to rotate in the opposite direction in the in-line configuration. Turbine performance testing was tested using a wind tunnel. The characteristics of crossflow wind turbines were investigated, then turbine performance was analyzed and discussed. The maximum power coefficient obtained was 0.169 (Cp) with the configuration of 12 turbine blades at a wind speed of 10 m/s. The maximum torque coefficient obtained was 0.703. The overall results show that the crossflow wind turbine in in-line configuration with opposite rotation can improve the performance of wind turbines.

Design of eddy current brake for electric motorcycle braking system

Abstract: Braking systems in motor vehicles generally use a braking system that utilizes friction. The braking performance will decrease caused by using friction rapidly. To overcome this, as an alternative, an electromagnetic braking system can be used by utilizing eddy currents, such as eddy current brakes (ECB). Eddy currents are generated when the rotor pass the magnetic field of the electromagnet. The research aim is to design an ECB system. The performance of the disk design will be determined in this study. The study is about the tendency of the ECB properties. The finite element (FEM) method is used by modeling ECB performance. The experimental results were used to validate the result. The test showed the results of braking using aluminum disk showed the best performance in 12.03 Nm. From these results, the combination of the disks is needed by an appropriate disk design.

Assessment of Designed Midship Section Structures subjected to the Hydrostatic and Hydrodynamic Loads: A Convergence Study

Abstract: This paper discusses the effect of element-length-to-thickness (ELT) ratio on midship structure analysis. Although it is widely known that every design must consider the best possible outcome of the design, indeed the simulation cannot produce the optimal analysis due to a variety of factors. During the study of the midship section configuration, the ELT ratio is one of the determining factors in the simulation. Since different ELT ratios would eventually produce different results, a calibration using the finite element method based on pioneer benchmarking studies is needed. The author designed a midship section using SolidWorks and ran the finite element analysis. The applied material is a titanium alloy, and the design’s boundary conditions are described as static loads, dynamic loads, and ELT ratios (in the range of 5-11). The midship design was tested with various ELT ratios, and the results, i.e., displacement, stress (von-Mises), and strain, were summarized. In terms of convergence tendency, midship displayed a displacement of 26.94 mm for the ELT ratio 10, with a strain of 5.579 × 10-4 and stress of 111.2 MPa. The displacement ratio was 0.97, the strain ratio was 0.917, and the stress ratio was 0.778 according to the simulation result. Different results can be presented by using different ELT ratios to assess the convergence tendency of the applied ELT ratios in finite element simulation. In contrast to the pioneer study, the ELT ratio converges on a scale of 10 with an average disparity of 11.16%.

An Optimum Design and Economic Analysis of Renewable PV-Standalone Power Plant for Electric Vehicle Charging Station in Indonesia

Abstract: Electric vehicles have recently been increasing in popularity and market demand which can be used as a key indicator for the future due to climate change and global warming so that CO2 emission reductions are needed. In addition to environmental factors which are the main motivation for the increase in electric vehicles, this type of transportation reduces dependence on fossil fuels and contributes a lot to energy independence. The increasing popularity of electric vehicles requires a country to build a charging station for the community in the future, including Indonesia. For that reason, this study was made to obtain the most optimal PV-standalone design as a charging station with the economic analysis. Semarang city is the location of choice because of the potential for strategic resources and is one of the cities with the highest number of vehicles. The result is that 23.2kW PV, 9kW converter, and 40kWh battery are the most optimal for charging stations in the city of Semarang with 10 electric cars every day, with a total daily load of 88kWh/day.