VARIABLE DETERMINED FOR OPTIMIZATION OF ALTERNATING ENERGY ON THE LOAD BY THE ADAPTIVE TAGUCHI METHOD

It is important to find the optimum point in terms of energy quality in the studies for electrical energy conversions with the converter and inverter circuits. In such studies, it has been tried to find the optimum operating point by using control systems such as PID and Fuzzy Logic in closed-loop controls. When a large number of variables are involved in finding the optimum point, closed-loop control methods such as these may be insufficient to find the optimum point. Therefore, in this study, the Adaptive Taguchi Method (ATM) with the maximum-minimum value is used for the estimation of variables providing the optimum point for energy quality by using it in a multilevel inverter with a double dc-dc converter. While in traditional Taguchi Methods, dependent variables predict the results by revealing their effects on independent variables, in ATM, besides the effects of the independent variables, the effects of different dependent variables on each other are also estimated. First, the system to which the ATM will be applied is introduced. Then, the principles of applying the ATM are explained. In the known Taguchi method, variable values to be found with 34 = 81 trials, variables are estimated with 27 trials, while the values of two different dependent variables in the system can be found with 54 trials instead of 2x34 = 2x81 trials. The resulting values to be estimated with the proposed ATM method are estimated with 27 trials instead of 2x81 or 54 trials. Finally, the observation results to be used for estimation are analyzed and evaluated. By trying the prediction results, it is seen that the proposed system is quite effective because the estimated result value that is %3.71 in the experiments gives a lesser distortion value than the values used for prediction.

Analytical model for the signal-to-noise-ratio of drift tube ion mobility spectrometers

While the resolving power of drift tube ion mobility spectrometers has been studied and modelled in detail over the past decades, no comparable model exists for the signal-to-noise-ratio. In this work, we develop an analytical model for the signal-to-noise-ratio of a drift tube ion mobility spectrometer based on the same experimental parameters used for modelling the resolving power. The resulting holistic model agrees well with experimental results and allows simultaneously optimizing both resolving power and signal-to-noise-ratio. Especially, it reveals several unexpected relationships between experimental parameters. First, even though reduced initial ion packet widths result in fewer injected ions and reduced amplifier widths result in more noise, the resulting shift of the optimum operating point when reducing both simultaneously leads to a constant signal-to-noise-ratio. Second, there is no dependence of the signal-to-noise-ratio at the optimum operating point on the drift length, as again the resulting shift of the optimum operating point causes all effects to compensate each other.

Identification of Optimal Parameters for a Small-Scale Compressed-Air Energy Storage System Using Real Coded Genetic Algorithm

Compressed-Air energy storage (CAES) is a well-established technology for storing the excess of electricity produced by and available on the power grid during off-peak hours. A drawback of the existing technique relates to the need to burn some fuel in the discharge phase. Sometimes, the design parameters used for the simulation of the new technique are randomly chosen, making their actual construction difficult or impossible. That is why, in this paper, a small-scale CAES without fossil fuel is proposed, analyzed, and optimized to identify the set of its optimal design parameters maximizing its performances. The performance of the system is investigated by global exergy efficiency obtained from energy and exergy analyses methods and used as an objective function for the optimization process. A modified Real Coded Genetic Algorithm (RCGA) is used to maximize the global exergy efficiency depending on thirteen design parameters. The results of the optimization indicate that corresponding to the optimum operating point, the consumed compressor electric energy is 103 . 83 k W h and the electric energy output is 25 . 82 k W h for the system charging and discharging times of about 8.7 and 2 h, respectively. To this same optimum operating point, a global exergy efficiency of 24.87% is achieved. Moreover, if the heat removed during the compression phase is accounted for in system efficiency evaluation based on the First Law of Thermodynamics, an optimal round-trip efficiency of 79.07% can be achieved. By systematically analyzing the variation of all design parameters during evolution in the optimization process, we conclude that the pneumatic motor mass flow rate can be set as constant and equal to its smallest possible value. Finally, a sensitivity analysis performed with the remaining parameters for the change in the global exergy efficiency shows the impact of each of these parameters.

Analisa Titik Operasi Optimum Pompa Slurry pada Bucket Wheel Dredger dengan Variasi Sudut Gali 30°, 35° dan 40°

PT.Timah (Persero) Tbk. merupakan perusahaan tambang timah dengan cadangan terbesar di dunia yang menggunakan kapal isap tipe Bucket Wheel Dredger sebagai salah satu metode penambangan lepas pantai. Untuk mendistribuskan material tambang dari dasar laut menuju unit penyaringan, digunakan air sebagai media pembawa dibantu dengan pompa melalui jaringan pemipaan. Pada proses pengerukan, ternyata didapat masih ada material logam timah yang tertinggal di dasar lautan. Hal ini menyebabkan pengerukan menjadi kurang maksimal. Oleh karena itu, diperlukan analisa untuk mencari kondisi operasi optimum untuk setiap kedalaman penggalian. Dalam penelitian ini, dilakukan perhitungan head secara teoritis dimana prosedur dimulai dengan pengumpulan data pendukung, kemudian melakukan perhitungan untuk mendapatkan hasil. Dalam kondisi lapangan, didapat perubahan luas penampang pipa dikarenakan erosi. Untuk menghitung head, digunakan persamaan Bernoulli, untuk kerugian head major dan head minor digunakan persamaan Darcy-Weisbach dimana kapasitas aliran adalah tetap 7747.2 m3/h dengan variasi sudut gali 30°,35°, dan 40° pada luas penampang dengan pemakaian baru, 1 bulan, 2 bulan, dan 3 bulan. Didapat titik operasi optimum pompa slurry untuk setiap sudut secara berurutan adalah pada 517.08 rpm, 517.44 rpm, 520.96 rpm untuk pemakaian baru; 517.44 rpm, 517.44 rpm, 521.664 rpm untuk pemakaian satu bulan ; 517.44 rpm, 517.792 rpm, 520.96 rpm untuk pemakaian dua bulan; 511.808 rpm, 512.16 rpm, 513.92 rpm untuk tiga bulan. PT. Timah (Persero) Tbk. is the largest tin mining company in the world which uses suction ships of Bucket Wheel Dredger as one of the offshore mining methods. Water is used as a carrier medium to distribute mining materials from seafloor to the filtration unit by pumps through piping networks. During the dredging process, it is found there is still tin metal material left on the ocean floor. This causes dredging process is less optimal. Based on the condition, it needed an analysis to find optimum operating process for each excavation depth. In this research, theoretical head calculations were carried out where the procedure began with supporting data collection, then calculated it to get results. In field conditions, changes in pipe cross section were obtained due to erosion. The Bernoulli equation was used to calculate head, Darcy-Weisbach equation was used for the loss of major and minor head where the flow capacity was fixed at 7747.2 m3/h with digging angle variations of 30 °, 35 °, and 40 ° in the cross-sectional area for new, 1 month, 2 months and 3 months usage. The optimum operating point of the slurry pump for each angles were obtained at 517.08 rpm, 517.44 rpm, 520.96 rpm for new usage; 517.44 rpm, 517.44 rpm, 521,664 rpm for one month usage; 517.44 rpm, 517,792 rpm, 520.96 rpm for two months usage; and 511,808 rpm, 512.16 rpm, 513.92 rpm for three months usage.

Performance influence in submersible pump with different diffuser inlet widths

The diffuser inlet width is a key geometric parameter that affects submersible pump performance. On the basis of diffuser characteristic curve analyses, diffusers with different inlet widths and the same impeller were equipped to construct a submersible pump model through the use of AutoCAD software. The performance curves of the submersible pump, with six diffuser inlet widths, were obtained using computational fluid dynamics method. Simultaneously, the simulation results were tested with the experimental method presented in this article. The results show that the optimum value of the inlet width ( b3 = 50 mm) is larger than the experience-based one. With an increase in the inlet width, the optimum operating point of a submersible pump offsets to a larger flow rate. When the guide blade inlet width is approximately 40–55 mm, the submersible pump efficiency is relatively high, approximately 75.9%–83.7% capacity, and the flow rate is approximately 105–135 m3/h. The numerical results of submersible pump performance are higher than those of the test results; however, their change trends have an acceptable agreement with each other. The practical significance is supplied by changing the inlet width of the diffuser to expand the scope of use.