Optimization of Wind Turbines Using Helicoidal Vortex Model

2003 ◽  
Author(s):  
Jean-Jacques Chattot
Keyword(s):  
Minimum Energy ◽  
Energy Condition ◽  
Integral Relation ◽  
Point Of View ◽  
Maximum Output ◽  
Efficient Design ◽  
Profile Data ◽  
Vortex Model ◽  
Viscous Profile ◽  
Optimum Solution

The problem of the design of a wind turbine for maximum output is addressed from an aerodynamical point of view. It is shown that the optimum inviscid design, based on the Goldstein model, satifies the minimum energy condition of Betz only for light loading. The more general equation governing the optimum is derived and an integral relation is obtained, stating that the optimum solution satisfies the minimum energy condition of Betz in the Trefftz plane “in the average”. The discretization of the problem is detailed, including the viscous correction based on the 2-D viscous profile data. A constraint is added to account for the force on the tower. The minimization problem is solved very efficiently by relaxation. Several optimized solutions are calculated and compared with the NREL rotor, using the same profile, but different chord and twist distributions. In all cases, the optimization produces a more efficient design.

Optimization of Wind Turbines Using Helicoidal Vortex Model

2003 ◽  
Vol 125 (4) ◽  
pp. 418-424 ◽  
Author(s):  
Jean-Jacques Chattot
Keyword(s):  
Minimum Energy ◽  
Energy Condition ◽  
Integral Relation ◽  
Point Of View ◽  
Maximum Output ◽  
Efficient Design ◽  
Profile Data ◽  
Vortex Model ◽  
Viscous Profile ◽  
Optimum Solution

The problem of the design of a wind turbine for maximum output is addressed from an aerodynamical point of view. It is shown that the optimum inviscid design, based on the Goldstein model, satisfies the minimum energy condition of Betz only in the limit of light loading. The more general equation governing the optimum is derived and an integral relation is obtained, stating that the optimum solution satisfies the minimum energy condition of Betz in the Trefftz plane “in the average.” The discretization of the problem is detailed, including the viscous correction based on the 2-D viscous profile data. A constraint is added to account for the thrust on the tower. The minimization problem is solved very efficiently by relaxation. Several optimized solutions are calculated and compared with the National Renewable Energy Laboratory (NREL) rotor, using the same profile, but different chord and twist distributions. In all cases, the optimization produces a more efficient design.

scholarly journals Sustainable Electric Personal Mobility: The Design of a Wireless Charging Infrastructure for Urban Tourism

2021 ◽  
Vol 13 (3) ◽  
pp. 1270
Author(s):  
Sung Il Kwag ◽  
Uhjin Hur ◽  
Young Dae Ko
Keyword(s):  
Public Transportation ◽  
New Technologies ◽  
Point Of View ◽  
Urban Tourism ◽  
Electric Mobility ◽  
Wireless Charging ◽  
Efficient Design ◽  
Personal Mobility ◽  
Charging Infrastructure ◽  
Mobility System

Though new technologies have been applied in all industries, electric mobility technology using eco-friendly energy is drawing a great deal of attention. This research focuses on a personal electric mobility system for urban tourism. Some tourism sites such as Gyeongju, Korea, have broad spaces for tourists to walk around, but the public transportation system has been insufficiently developed due to economic reasons. Therefore, personal mobility technology such as electric scooters can be regarded as efficient alternatives. For the operation of electric scooters, a charging infrastructure is necessary. Generally, scooters can be charged via wires, but this research suggests an advanced electric personal mobility system based on wireless electric charging technology that can accommodate user convenience. A mathematical model-based optimization was adopted to derive an efficient design for a wireless charging infrastructure while minimizing total investment costs. By considering the type of tourists and their tour features, optimal locations and lengths of the static and dynamic wireless charging infrastructure are derived. By referring to this research, urban tourism can handle transportation issues from a sustainable point of view. Moreover, urban tourism will have a better chance of attracting tourists by conserving heritage sites and by facilitating outdoor activities with electric personal mobility.

scholarly journals Experimental Measurement of Absorption Coefficients for Effective Erbium-Doping Concentration to Optimize Few-Mode Erbium-Doped Fiber Amplifiers with Low Differential Mode Gain

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 185
Author(s):  
Yan Xu ◽  
Baojian Wu ◽  
Xinrui Jiang ◽  
Haomiao Guo ◽  
Feng Wen
Keyword(s):  
Doping Concentration ◽  
Point Of View ◽  
Fiber Amplifiers ◽  
Efficient Design ◽  
Absorption Loss ◽  
Differential Mode ◽  
Transmission Method ◽  
Modal Gain ◽  
Analysis Process ◽  
Erbium Doped

According to the analytical expression for modal gain of few-mode erbium-doped fiber amplifiers (FM-EDFAs), we propose a method of measuring the absorption loss coefficients of few-mode signals in few-mode erbium-doped fibers (FM-EDFs) by extrapolating the mode–gain curve dependent on the average population inversion. The absorption loss coefficient of an FM-EDF was measured in our experimental platform and used to estimate the effective erbium-ion doping concentration. The feasibility of the extrapolation method was verified by simulation and comparison with the transmission method. Furthermore, the FM-EDFAs with high modal gain and low differential mode gain (DMG) could be optimized by adjusting the FM-EDF’s length and pump power. The analysis process presented here is very useful for the efficient design of FM-EDFAs from a practical point of view.

scholarly journals A New Graphical Technique for Energy Efficient Design of Heat Recovery System in Chemical/Refining Industries

2016 ◽  
Vol 4 (4) ◽  
pp. 33
Author(s):  
Dina Ahmed Kamel ◽  
Mamdouh Ayad Gadalla ◽  
Fatma Hanafy Ashour
Keyword(s):  
Heat Exchanger ◽  
Driving Forces ◽  
Process Integration ◽  
Minimum Energy ◽  
Pinch Analysis ◽  
Efficient Design ◽  
Heating And Cooling ◽  
Heat Exchanger Networks ◽  
Graphical Technique ◽  
Key Steps

Chemical processes are energy intensive industries; the majority of energy consumed in industrial processes is mainly used for heating and cooling requirements. This results in increasing the interest in obtaining the optimum design of the heat exchanger networks to reduce the energy consumption and face the growing energy crises. Most of the published literature over the last fifty years promotes the process integration technology as a main part of the process system engineering science. Graphical Pinch Analysis method normally includes two key steps, firstly obtaining the energy targets which include the minimum energy required for the HEN design, then designing the heat exchanger network (HEN). This paper introduces a new graphical approach for the design of new heat exchanger networks (HENs) based on pinch analysis rules. The HEN is represented on a simple graph, where the cold stream temperatures are plotted on the X-axis while the driving forces for each exchanger are plotted on the Y-axis. This graphical technique can describe the energy analysis problems in term of temperature driving force inside the heat exchanger, which is an important factor in the design process as the differences in these driving forces are involved in calculating the area of heat exchangers, and consequently affecting the cost.

scholarly journals A Highly D‑efficient Spring Balance Weighing Design for an Even Number of Objects

2019 ◽  
Vol 5 (344) ◽  
pp. 17-27
Author(s):  
Małgorzata Graczyk ◽  
Bronisław Ceranka
Keyword(s):  
Optimal Design ◽  
Sufficient Conditions ◽  
Optimality Criteria ◽  
Point Of View ◽  
Necessary And Sufficient Conditions ◽  
Optimal Designs ◽  
Efficient Design ◽  
Spring Balance ◽  
Experimental Errors ◽  
Necessary And Sufficient

The problem of determining unknown measurements of objects in the model of spring balance weighing designs is presented. These designs are considered under the assumption that experimental errors are uncorrelated and that they have the same variances. The relations between the parameters of weighing designs are deliberated from the point of view of optimality criteria. In the paper, designs in which the product of the variances of estimators is possibly the smallest one, i.e. D‑optimal designs, are studied. A highly D‑efficient design in classes in which a D‑optimal design does not exist are determined. The necessary and sufficient conditions under which a highly efficient design exists and methods of its construction, along with relevant examples, are introduced.

Modelling of interactions in solutions: alkali halides in DMSO

1979 ◽  
Vol 57 (5) ◽  
pp. 538-551 ◽  
Author(s):  
Peeter Kruus ◽  
Barbara E. Poppe
Keyword(s):  
Reasonable Agreement ◽  
Minimum Energy ◽  
Alkali Halides ◽  
Ion Pair ◽  
Point Of View ◽  
Ion Solvation ◽  
Solvation Energies ◽  
Solvent Molecules ◽  
A Charge ◽  
Energy Configurations

A model of solutions of alkali halides in DMSO is developed. Each ion is described by a radius, a charge, a polarizability, and an exponential repulsion parameter. Each molecule is described by a polarizability, charges, 6-12 energy parameters, and 6-12 distance parameters centered on each of the 10 atoms in the molecule. The model is applied to calculate (i) the vaporization energy of solvent molecules, (ii) single ion solvation energies and configurations of the solvating molecules, and (iii) the energy as a function of reaction coordinate for the formation of an ion pair. The energies and configurations are obtained by allowing the systems to relax to minimum energy configurations by allowing motion of the molecules. The results of (i) give a vaporization energy 60% of the experimental. The results of (ii) give solvation energies in reasonable agreement with the experimental, and configurations which are reasonable from the point of view of mobilities of ions. The results of (iii) show the presence of a distinct solvent separated ion pair which actually has an energy lower than the contact ion pair. Advantages and problems involved in using this approach to model solutions are discussed.

scholarly journals A Novel Check-List Strategy to Evaluate the Potential of Operational Improvements in Wastewater Treatment Plants

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5005
Author(s):  
Vojtěch Zejda ◽  
Vítězslav Máša ◽  
Šárka Václavková ◽  
Pavel Skryja
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Minimum Energy ◽  
Correct Selection ◽  
Maximum Output ◽  
Wastewater Treatment Process ◽  
Efficient Operation ◽  
Efficiency Assessment ◽  
Pump Station ◽  
Basic Parameters

With increasing demands for cleaning and purification of water, wastewater treatment plants (WWTP) require their most efficient operation. The operators are thus obliged to constantly review the efficiency of the processing units and technological equipment of WWTPs and seek opportunities for improvements. To increase the efficiency of particular equipment, the important parameters to be used for the intensification must be correctly selected. A common WWTP consists of different types of processing units, where the basic parameters can be changed to achieve the highest efficiency (i.e., maximum output with minimum energy consumption) in the WWTP. However, due to many possible technologies in the wastewater treatment process, the combinations of processing units can be complex. In such cases, the efficiency assessment can be misleading if only basic parameters were accessed. Moreover, single-unit intensification can potentially improve the efficiency of the unit itself but cannot guarantee full process improvement. This can be due to negative causal effects in the downstream due to that unit intensification. This work reviews of key parameters at five selected pieces of WWTP equipment (inlet pump station, airlift pump, primary sedimentation tank, aeration chamber, and mixing of anaerobic digester) to demonstrate the correct selection of all affected parameters for the efficiency assessment. In the context of the whole WWTP process, it is necessary to take into account several other parameters to evaluate the efficiency of the equipment. Finally, a methodology for assessing the significance of the identified parameters is proposed. This methodology is effectively applied and demonstrated in the WWTP case study.

scholarly journals On the Predictive Power of the Minimum Energy Condition

1993 ◽  
Vol 157 ◽  
pp. 413-414
Author(s):  
Martin Pohl
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Predictive Power ◽  
Spiral Galaxies ◽  
Minimum Energy ◽  
Energy Condition ◽  
Cosmic Ray ◽  
Γ Ray ◽  
Minimum Energy Method ◽  
The Magnetic Field

We reexamine the minimum energy method to determine the magnetic field strength in spiral galaxies from the cosmic ray standpoint of view. It is shown that for example in M51 the estimated field strength is about a factor of 2 lower than obtained with the standard method. As a by-product the corresponding γ-ray flux from the galaxies can be calculated, which will allow further improvement of the method provided reliable γ-ray spectra are at hand.

scholarly journals Building Design Influence On The Energy Performance

2015 ◽  
Vol 5 (1) ◽  
pp. 37-46
Author(s):  
Ligia Moga ◽  
I. Moga
Keyword(s):  
Residential Building ◽  
Building Design ◽  
Energy Performance ◽  
Point Of View ◽  
Hot Water ◽  
Efficient Design ◽  
Building Stock ◽  
Existing Building ◽  
Climatic Regions ◽  
Energy Consumptions

Abstract Energy efficient design is a high priority in the national energy strategy of European countries considering the latest requirements of the European Directive on the Energy Performance of Buildings. The residential sector is responsible for a significant quantity of energy consumptions from the total amount of consumptions on a worldwide level. In residential building most of the energy consumptions are given mainly by heating, domestic hot water and lighting. Retrofitting the existing building stock offers great opportunities for reducing global energy consumptions and greenhouse gas emissions. The first part of the paper will address the need of thermal and energy retrofit of existing buildings. The second part will provide an overview on how various variables can influence the energy performance of a building that is placed in all four climatic zones from Romania. The paper is useful for specialist and designers from the construction field in understanding that buildings behave differently from the energy point of view in different climatic regions, even if the building characteristic remain the same.

scholarly journals The Influence of Mesh Granularity on the Accuracy of FEM Modelling of the Resonant State in a Microwave Chamber

2021 ◽  
Vol 11 (17) ◽  
pp. 7932
Author(s):  
Anna Ostaszewska-Liżewska ◽  
Dominika Kopala ◽  
Jakub Szałatkiewicz ◽  
Roman Szewczyk ◽  
Peter Råback
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Open Source ◽  
Resonant State ◽  
Point Of View ◽  
Tetrahedral Mesh ◽  
Efficient Design ◽  
Resonant States ◽  
Main Barrier ◽  
Element Method

Microwave technology is widely used in different areas of advanced industry when energy must be provided to water-containing and other materials. The main barrier in the development of microwave devices is the possibility of efficient design by modelling a microwave system in a resonant state. For technical systems, the finite element method is widely used. However, the convergence process in the microwave finite element solver is sophisticated. The process itself and the influence of mesh granularity on the accuracy of modelling of microwave chambers in resonant states have not been investigated previously. The present paper aims to fill this gap. The resonance conditions of a microwave chamber were tested from the point of view of spatial resolution of the tetrahedral mesh used for open-source ELMER FEM software. The presented results experimentally determine the limits of accuracy of the geometry of microwave resonant chamber finite element method-based models. The determined values of microwave resonant chamber dimension tolerances should be considered for both open-source and commercial software for microwave modelling.

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