A critical evaluation of deterministic methods in size optimisation of reliable and cost effective standalone Hybrid renewable energy systems

Reliability of a hybrid renewable energy system (HRES) strongly depends on various uncertainties affecting the amount of power produced by the system. In the design of systems subject to uncertainties, both deterministic and nondeterministic design approaches can be adopted. In a deterministic design approach, the designer considers the presence of uncertainties and incorporates them indirectly into the design by applying safety factors. It is assumed that, by employing suitable safety factors and considering worst-case-scenarios, reliable systems can be designed. In fact, the multi-objective optimisation problem with two objectives of reliability and cost is reduced to a single-objective optimisation problem with the objective of cost only. In this paper the competence of deterministic design methods in size optimisation of reliable standalone wind-PV-battery, wind-PV-diesel and wind-PV-battery-diesel configurations is examined. For each configuration, first, using different values of safety factors, the optimal size of the system components which minimises the system cost is found deterministically. Then, for each case, using a Monte Carlo simulation, the effect of safety factors on the reliability and the cost are investigated. In performing reliability analysis, several reliability measures, namely, unmet load, blackout durations (total, maximum and average) and mean time between failures are considered. It is shown that the traditional methods of considering the effect of uncertainties in deterministic designs such as design for an autonomy period and employing safety factors have either little or unpredictable impact on the actual reliability of the designed wind-PV-battery configuration. In the case of wind-PV-diesel and wind-PV-battery-diesel configurations it is shown that, while using a high-enough margin of safety in sizing diesel generator leads to reliable systems, the optimum value for this margin of safety leading to a cost-effective system cannot be quantified without employing probabilistic methods of analysis. It is also shown that deterministic cost analysis yields inaccurate results for all of the investigated configurations

Performance prediction of wind turbines utilizing passive smart blades: approaches and evaluation

The induced deformation, because of the presence of elastic coupling in the structure of passive smart blades, is the key parameter that affects the wind turbine aerodynamic performance, namely rotor mechanical power and blade loading. Therefore, in order to determine the aerodynamic performance of these turbines, a structural analyser is also required to bring the effect of the induced deformation into account. When predicting the rotor mechanical power, additional complexity arises when the blades are bend-twist-coupled. In this case, an iterative coupled-aero-structure analysis must be carried out at each given wind speed. Further difficulties in simulation of these turbines are posed by the fact that the current analytical models for analysis of structures made of anisotropic composite materials are not accurate enough. This differentiates the numerical simulation of wind turbines utilizing passive smart blades from the simulation of wind turbines with conventional blades. Different strategies have been proposed and followed by investigators in simulation of wind turbines utilizing passive smart blades. These methods can be categorized by the approach adopted in treating the torsional-induced deformation. In these studies, the induced twist has been predicted, planned or a combination of both. The present paper describes, evaluates and compares these approaches

Facilitating meta-design techniques for multi-disciplinary conceptual design

The research reported in this paper was supported by the EU FP6 funded project, SimSAC (Simulating Aircraft Stability and Control Characteristics for Use in Conceptual Design)

Optimal design of wind turbine blades equipped with flaps

As a result of the significant growth of wind turbines in size, blade load control has become the main challenge for large wind turbines. Many advanced techniques have been investigated aiming at developing control devices to ease blade loading. Amongst them, trailing edge flaps have been proven as effective devices for load alleviation. The present study aims at investigating the potential benefits of flaps in enhancing the energy capture capabilities rather than blade load alleviation. A software tool is especially developed for the aerodynamic simulation of wind turbines utilising blades equipped with flaps. As part of the aerodynamic simulation of these wind turbines, the control system must be also simulated. The simulation of the control system is carried out via solving an optimisation problem which gives the best value for the controlling parameter at each wind turbine run condition. Developing a genetic algorithm optimisation tool which is especially designed for wind turbine blades and integrating it with the aerodynamic performance evaluator, a design optimisation tool for blades equipped with flaps is constructed. The design optimisation tool is employed to carry out design case studies. The results of design case studies on wind turbine AWT-27 (Aerodynamic Wind Turbine-27) reveal that, as expected, the location of flap is a key parameter influencing the amount of improvement in the power extraction. The best location for placing a flap is at about 70% of the blade span from the root of the blade. The size of the flap has also significant effect on the amount of enhancement in the average power. This effect, however, reduces dramatically as the size increases. For constant speed rotors, adding flaps without re-designing the topology of the blade can improve the power extraction capability as high as of about 5%. However, with re-designing the blade pretwist the overall improvement can be reached as high as 12%

Multiobjective Optimisation and Integrated Design of Wind Turbine Blades Using WTBM-ANSYS for High Fidelity Structural Analysis

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THE POLITICAL PERCEPTION OF YOUTH IN BANGLADESH

AbstractYouth in politics can be a creative force, a dynamic source of innovation which in turn brings positive changes in political systems. But today’s youth is neither deeply apathetic nor unconventionally engaged in mainstream politics due to its complex nature. This decreasing level of youth participation in politics not only endangers the quality of leadership but also jeopardizes the democracy of tomorrow. By using qualitative and quantitative data this study explored the trend of youth engagement and their disconnection with the current political systems. This study aimed to observe how the youth is unbundling the traditional concept of state power and identify the reasons for their non-engagement in politics which eventually challenges the political system of Bangladesh

MOHRES, a Software Tool for Analysis and Multiobjective Optimisation of Hybrid Renewable Energy Systems : An Overview of Capabilities

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STUDI PERBANDINGAN PASIR, IJUK DAN LIMBAH PLASTIK SEBAGAI DRAINASE VERTIKAL

Bangunan yang direncanakan diatas suatu lapisan tanah lunak harus mempertimbangkan daya dukung tanah yang sangat terbatas serta penurunan yang cukup besar dimana akan membutuhkan waktu yang lama sekali. Lapisan yang lunak ini harus diperbaiki kondisinya sebelum bangunan dibangun di atasnya. Salah satu cara untuk mempercepat penurunan pada tanah lunak adalah menggunakan drainase vertikal. Drainase vertikal yang umum digunakan adalah berupa Sand Drains dan Prefabricated Vertical Drains (PVD). Permasalahan yang timbul dalam perbaikan tanah menggunakan drainase vertikal adalah biaya yang tidak murah pada operasional dan material pengisi drainase vertikal. Dalam penelitian ini akan dilakukan percobaan perbandingan drainase vertikal dengan bahan pengisi berupa pasir, ijuk dan limbah plastik. Penelitian ini dilakukan untuk mengetahui kemampuan drainase vertikal denngan bahan pengisi pasir, ijuk dan limbah plastik terhadap kecepatan penurunan tanah lunak. Penelitian ini dilakukan dengan membuat model di laboratorium. Pembebanan yang dilakukan ada 4 tahap, yaitu beban 0.25 ton, 0.5 ton, 1 ton dan 1.175 masing-masing dilakukan 4 hari pengamatan. Diameter drainase yang dipakai adalah 2.5 cm dengan jarak antar drainase vertikal 18.75 cm dengan pola susunan segiempat pada tanah lunak dengan ketebalan 50 cm dan dalam kondisi double drain. Ada 4 pengujian, yaitu pengujian tanah lunak tanpa drainase vertikal, tanah lunak dengan drainase vertikal pasir, tanah lunak dengan drainase vertikal ijuk dan tanah lunak dengan drainase vertikal plastik. Pasir dilakukan penyaringan sebelum digunakan, ijuk yang dipakai dari pohon aren dan limbah plastik yang digunakan adalah sampah botol plastik dengan ukuran ±1cm. Hasil pengujian menunjukkan bahwa metode perbaikan tanah menggunakan drainase vertikal dengan bahan pengisi limbah plastik terbukti lebih baik daripada drainase vertikal Ijuk dan pasir dalam mempercepat penurunan. Hal ini ditunjukkan adanya peningkatan koefisien konsolidasi arah vertikal sebesar 812.414% dibandingkan dengan koefisien konsolidasi pada tanah lunak tanpa drainase vertikal. Pada drainase vertikal pasir meningkatkan 576.196% dan drainase vertikal ijuk meningkatkan 696.268% dari koefisien konsolidasi arah vertikal tanah lunak tanpa drainase vertikal

Multiobjective Optimisation of Job Shop Scheduling of Renewable Powered Machinery

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