WorldWideScience

Sample records for wind collecting tower

  1. Wind-induced response analysis of a wind turbine tower including the blade-tower coupling effect

    Institute of Scientific and Technical Information of China (English)

    Xiao-bo CHEN; Jing LI; Jian-yun CHEN

    2009-01-01

    To analyze wind-induced response characteristics of a wind turbine tower more accurately, the blade-tower coupling effect was investigated. The mean wind velocity of the rotating blades and tower was simulated according to wind shear effects,and the fluctuating wind velocity time series of the wind turbine were simulated by a harmony superposition method. A dynamic finite element method (FEM) was used to calculate the wind-induced response of the blades and tower. Wind-induced responses of the tower were calculated in two cases (one included the blade-tower coupling effect, and the other only added the mass of blades and the hub at the top of the tower), and then the maximal displacements at the top of the tower of the tow cases were compared with each other. As a result of the influence of the blade-tower coupling effect and the total base shear of the blades, the maximal displacement of the first case increased nearly by 300% compared to the second case. To obtain more precise analysis, the blade-tower coupling effect and the total base shear of the blades should be considered simultaneously in the design of wind turbine towers.

  2. Adaptive Backstepping Control of Lightweight Tower Wind Turbine

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Borup, Kasper Trolle; Niemann, Hans Henrik

    2015-01-01

    the angular deflection of the tower with respect to the vertical axis in response to variations in wind speed. The controller is shown to guarantee asymptotic tracking of the reference trajectory. The performance of the control system is evaluated through deterministic and stochastic simulations including......This paper investigates the feasibility of operating a wind turbine with lightweight tower in the full load region exploiting an adaptive nonlinear controller that allows the turbine to dynamically lean against the wind while maintaining nominal power output. The use of lightweight structures...... for towers and foundations would greatly reduce the construction cost of the wind turbine, however extra features ought be included in the control system architecture to avoid tower collapse. An adaptive backstepping collective pitch controller is proposed for tower point tracking control, i.e. to modify...

  3. Wind tower service lift

    Science.gov (United States)

    Oliphant, David; Quilter, Jared; Andersen, Todd; Conroy, Thomas

    2011-09-13

    An apparatus used for maintaining a wind tower structure wherein the wind tower structure may have a plurality of legs and may be configured to support a wind turbine above the ground in a better position to interface with winds. The lift structure may be configured for carrying objects and have a guide system and drive system for mechanically communicating with a primary cable, rail or other first elongate member attached to the wind tower structure. The drive system and guide system may transmit forces that move the lift relative to the cable and thereby relative to the wind tower structure. A control interface may be included for controlling the amount and direction of the power into the guide system and drive system thereby causing the guide system and drive system to move the lift relative to said first elongate member such that said lift moves relative to said wind tower structure.

  4. Composite wind turbine towers

    Energy Technology Data Exchange (ETDEWEB)

    Polyzois, D. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Civil Engineering

    2008-07-01

    This paper discussed experiments conducted to optimized the advanced composite materials such as fiberglass reinforced plastics (FRP) used to fabricate wind turbine towers. FRP materials are used in tubular steel, lattice, guyed, and reinforced concrete towers. The towers and turbine blades are transported in segments and assembled on-site, sometimes in offshore or remote locations.The FRP composites are used to build towers with a high strength-to-weight ratio as well as to provide resistance to chemical attacks and corrosion. Use of the materials has resulted in towers that do not require heavy installation equipment. Experimental programs were conducted to verify the structural behaviour of the tower structure's individual-scaled cells as well as to evaluate the performance of multi-cell assemblies. Joint assembly designs were optimized, and a filament winding machine was used to conduct the experimental study and to test individual cells. Failure mode analyses were conducted to determine local buckling and shear rupture. Tension, compression, and shear properties of the FRP materials were tested experimentally, and data from the test were then used to develop finite element models of the composite towers as well as to obtain load deflection curves and tip oscillation data. A case study of a 750 kW wind turbine in Churchill, Manitoba was used to test the design. tabs., figs.

  5. Analysis of Ideal Towers for Tall Wind Applications

    Energy Technology Data Exchange (ETDEWEB)

    Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Damiani, Rick R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Roberts, Joseph O [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lantz, Eric J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-01-12

    Innovation in wind turbine tower design is of significant interest for future development of wind power plants. First, wind turbine towers account for a large portion of overall capital expenditures for wind power projects. Second, for low wind-resource regions of the world, the use of low-cost tall-tower technology has the potential to open new markets for development. This study investigates the relative potential of various tower configurations in terms of mass and cost. For different market applications and hub heights, idealized tall towers are designed and compared. The results show that innovation in wind turbine controls makes reaching higher hub heights with current technology economically viable. At the same time, new technologies hold promise for reducing tower costs as these technologies mature and hub heights reach twice the current average.

  6. Analysis of Ideal Towers for Tall Wind Applications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Damiani, Rick R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Roberts, Joseph O [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lantz, Eric J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-27

    Innovation in wind turbine tower design is of significant interest for future development of wind power plants. First, wind turbine towers account for a large portion of overall capital expenditures for wind power projects. Second, for low wind-resource regions of the world, the use of low-cost tall-tower technology has the potential to open new markets for development. This study investigates the relative potential of various tower configurations in terms of mass and cost. For different market applications and hub heights, idealized tall towers are designed and compared. The results show that innovation in wind turbine controls makes reaching higher hub heights with current technology economically viable. At the same time, new technologies hold promise for reducing tower costs as these technologies mature and hub heights reach twice the current average.

  7. Research Based on the Acoustic Emission of Wind Power Tower Drum Dynamic Monitoring Technology

    Science.gov (United States)

    Zhang, Penglin; Sang, Yuan; Xu, Yaxing; Zhao, Zhiqiang

    Wind power tower drum is one of the key components of the wind power equipment. Whether the wind tower drum performs safety directly affects the efficiency, life, and performance of wind power equipment. Wind power tower drum in the process of manufacture, installation, and operation may lead to injury, and the wind load and gravity load and long-term factors such as poor working environment under the action of crack initiation or distortion, which eventually result in the instability or crack of the wind power tower drum and cause huge economic losses. Thus detecting the wind power tower drum crack damage and instability is especially important. In this chapter, acoustic emission is used to monitor the whole process of wind power tower drum material Q345E steel tensile test at first, and processing and analysis tensile failure signal of the material. And then based on the acoustic emission testing technology to the dynamic monitoring of wind power tower drum, the overall detection and evaluation of the existence of active defects in the whole structure, and the acoustic emission signals collected for processing and analysis, we could preliminarily master the wind tower drum mechanism of acoustic emission source. The acoustic emission is a kind of online, efficient, and economic method, which has very broad prospects for work. The editorial committee of nondestructive testing qualification and certification of personnel teaching material of science and technology industry of national defense, "Acoustic emission testing" (China Machine Press, 2005.1).

  8. Damping of wind turbine tower vibrations

    DEFF Research Database (Denmark)

    Brodersen, Mark Laier; Pedersen, Mikkel Melters

    Damping of wind turbine vibrations by supplemental dampers is a key ingredient for the continuous use of monopiles as support for offshore wind turbines. The present thesis consists of an extended summary with four parts and appended papers [P1-P4] concerning novel strategies for damping of tower...... dominated vibrations.The first part of the thesis presents the theoretical framework for implementation of supplemental dampers in wind turbines. It is demonstrated that the feasibility of installing dampers at the bottom of the tower is significantly increased when placing passive or semiactive dampers...... in a stroke amplifying brace, which amplifies the displacement across the damper and thus reduces the desired level of damper force. For optimal damping of the two lowest tower modes, a novel toggle-brace concept for amplifying the bending deformation of the tower is presented. Numerical examples illustrate...

  9. Dynamic response of wind turbine towers in warm permafrost

    Institute of Scientific and Technical Information of China (English)

    Benjamin Still; ZhaoHui Joey Yang; Simon Evans; FuJun Niu

    2014-01-01

    Wind is a great source of renewable energy in western Alaska. Consistent winds blow across the barren tundra underlain by warm permafrost in the winter season, when the energy demand is the highest. Foundation engineering in warm permafrost has always been a challenge in wind energy development. Degrading warm permafrost poses engineering issues to design, construction, and operation of wind turbines. This paper describes the foundation design of a wind turbine built in western Alaska. It presents a sys-tem for response monitoring and load assessment, and data collected from September 2013 to March 2014. The dynamic proper-ties are assessed based on the monitoring data, and seasonal changes in the dynamic properties of the turbine tower-foundation system and likely resonance between the spinning blades and the tower structure are discussed. These analyses of a wind turbine in warm permafrost are valuable for designing or retrofitting of foundations in warm permafrost.

  10. Lifting system and apparatus for constructing wind turbine towers

    Science.gov (United States)

    Livingston, Tracy; Schrader, Terry; Goldhardt, James; Lott, James

    2011-02-01

    The disclosed invention is utilized for mounting a wind turbine and blade assembly on the upper end of a wind turbine tower. The invention generally includes a frame or truss that is pivotally secured to the top bay assembly of the tower. A transverse beam is connected to the frame or truss and extends fore of the tower when the frame or truss is in a first position and generally above the tower when in a second position. When in the first position, a wind turbine or blade assembly can be hoisted to the top of the tower. The wind turbine or blade assembly is then moved into position for mounting to the tower as the frame or truss is pivoted to a second position. When the turbine and blade assembly are secured to the tower, the frame or truss is disconnected from the tower and lowered to the ground.

  11. Numerical Simulation of Wind Turbine Blade-Tower Interaction

    Institute of Scientific and Technical Information of China (English)

    Qiang Wang; Hu Zhou; Decheng Wan

    2012-01-01

    Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface (AMI) method were presented.The governing equations were the unsteady Reynolds-averaged Navier-Stokes (PANS) which were solved by the pimpleDyMFoam solver,and the AMI method was employed to handle mesh movements.The National Renewable Energy Laboratory (NREL) phase Ⅵ wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds (5,10,15,and 25 m/s) at a fixed blade pitch and constant rotational speed.Detailed numerical results of vortex structure,time histories of thrust,and pressure distribution on the blade and tower were presented.The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine,while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower.Also,strong interaction of blade tip vortices with separation from the tower was observed.

  12. Aerodynamical errors on tower mounted wind speed measurements due to the presence of the tower

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, H. [Uppsala Univ. (Sweden). Dept. of Meteorology; Dahlberg, J.Aa. [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

    1996-12-01

    Field measurements of wind speed from two lattice towers showed large differences for wind directions where the anemometers of both towers should be unaffected by any upstream obstacle. The wind speed was measured by cup anemometers mounted on booms along the side of the tower. A simple wind tunnel test indicates that the boom, for the studied conditions, could cause minor flow disturbances. A theoretical study, by means of simple 2D flow modelling of the flow around the mast, demonstrates that the tower itself could cause large wind flow disturbances. A theoretical study, based on simple treatment of the physics of motion of a cup anemometer, demonstrates that a cup anemometer is sensitive to velocity gradients across the cups and responds clearly to velocity gradients in the vicinity of the tower. Comparison of the results from the theoretical study and field tests show promising agreement. 2 refs, 8 figs

  13. Wind turbine tower for storing hydrogen and energy

    Science.gov (United States)

    Fingersh, Lee Jay [Westminster, CO

    2008-12-30

    A wind turbine tower assembly for storing compressed gas such as hydrogen. The tower assembly includes a wind turbine having a rotor, a generator driven by the rotor, and a nacelle housing the generator. The tower assembly includes a foundation and a tubular tower with one end mounted to the foundation and another end attached to the nacelle. The tower includes an in-tower storage configured for storing a pressurized gas and defined at least in part by inner surfaces of the tower wall. In one embodiment, the tower wall is steel and has a circular cross section. The in-tower storage may be defined by first and second end caps welded to the inner surface of the tower wall or by an end cap near the top of the tower and by a sealing element attached to the tower wall adjacent the foundation, with the sealing element abutting the foundation.

  14. The design and stability determination of wind turbine tower

    International Nuclear Information System (INIS)

    Abas Abd Wahab; Khairul Barriyah

    2001-01-01

    In wind turbine tower design, two load categories (static and wind load) were considered. The static load for this structure is the tower self-weight, which can be calculated from its density and area of the material, whereas the wind load was calculated based on CP3: Chapter V: Part 2: 1972, using the maximum wind speed of 30 m/s. The stability of this tower under the action of these two loads has been determined using RISA-3D program. The program were subjected to two joint types, i.e pinned and fixed joints. The tower using fixed joint members has established the necessary tower stability. The simulation, calculation and results are being discussed in detail in this paper. (Author)

  15. Mechanical Properties of UHPFRC Joint for FORIDA Wind Turbine Tower

    DEFF Research Database (Denmark)

    Sørensen, Eigil Verner

    FORIDA Development, Vestas and Aalborg University are currently undertaking the project “FORIDA Hybrid Towers – The towers for next generation of wind turbines”, aiming to develop a new wind turbine tower structure (The FORIDA Tower) for very tall turbines. The tower is going to be a hybrid of ma...

  16. Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

    Institute of Scientific and Technical Information of China (English)

    Binrong WEN; Sha WEI; Kexiang WEI; Wenxian YANG; Zhike PENG; Fulei CHU

    2017-01-01

    The magnitude and stability of power output are two key indices of wind turbines.This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine.First,wind speed models,particularly the wind shear model and the tower shadow model,are described in detail.The widely accepted tower shadow model is modified in view of the cone-shaped towers of modem large-scale wind turbines.Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory.Results indicate that power fluctuation is mainly caused by tower shadow,whereas power loss is primarily induced by wind shear.Under steady wind conditions,power loss can be divided into wind farm loss and rotor loss.Wind farm loss is constant at 3α(3α-1)R2/(8H2).By contrast,rotor loss is strongly influenced by the wind turbine control strategies and wind speed.That is,when the wind speed is measured in a region where a variable-speed controller works,the rotor loss stabilizes around zero,but when the wind speed is measured in a region where the blade pitch controller works,the rotor loss increases as the wind speed intensifies.The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.

  17. Performance Evaluation of a Modular Design of Wind Tower with Wetted Surfaces

    Directory of Open Access Journals (Sweden)

    Sajad M.R. Khani

    2017-06-01

    Full Text Available Wind towers or wind catchers, as passive cooling systems, can provide natural ventilation in buildings located in hot, arid regions. These natural cooling systems can provide thermal comfort for the building inhabitants throughout the warm months. In this paper, a modular design of a wind tower is introduced. The design, called a modular wind tower with wetted surfaces, was investigated experimentally and analytically. To determine the performance of the wind tower, air temperature, relative humidity (RH and air velocity were measured at different points. Measurements were carried out when the wind speed was zero. The experimental results were compared with the analytical ones. The results illustrated that the modular wind tower can decrease the air temperature significantly and increase the relative humidity of airflow into the building. The average differences for air temperature and air relative humidity between ambient air and air exiting from the wind tower were approximately 10 °C and 40%, respectively. The main advantage of the proposed wind tower is that it is a modular design that can reduce the cost of wind tower construction.

  18. Along-wind response of a wind turbine tower with blade coupling subjected to rotationally sampled wind loading

    Energy Technology Data Exchange (ETDEWEB)

    Murtagh, P J; Basu, B; Broderick, B M [Department of Civil, Structural and Environmental Engineering, Trinity College, Dublin (Ireland)

    2005-07-15

    This paper proposes an approach to investigate the along-wind forced vibration response of a wind turbine tower and rotating blades assembly subjected to rotationally sampled stationary wind loading. The wind turbine assembly consists of three rotating rotor blades connected to the top of a flexible annular tower, constituting a multi-body dynamic entity. The tower and rotating blades are each modelled as discretized multi-degree-of-freedom (MDOF) entities, allowing the free vibration characteristics of each to be obtained using a discrete parameter approach. The free vibration properties of the tower include the effect of a rigid mass at the top, representing the nacelle, and those of the blade include the effects of centrifugal stiffening due to rotation and blade gravity loadings. The blades are excited by drag force time-histories derived from discrete Fourier transform (DFT) representations of rotationally sampled wind turbulence spectra. Blade response time-histories are obtained using the mode acceleration method, which allows for the quantification of base shear forces due to flapping for the three blades to be obtained. This resultant base shear is imparted into the top of the tower. Wind drag loading on the tower is also considered, with a series of spatially correlated nodal force time-histories being derived using DFTs of wind force spectra. The tower/nacelle is then coupled with the rotating blades by combining their equations of motion and solving for the displacement at the top of the tower under compatibility conditions in the frequency domain. An inverse Fourier transform of the frequency domain response yields the response time-history of the coupled system. The response of an equivalent system that does not consider the blade/tower interaction is also investigated, and the results are compared. (Author)

  19. Dynamic Analysis of Wind Power Turbine's Tower under the Combined Action of Winds and Waves

    Institute of Scientific and Technical Information of China (English)

    CHENG You-liang; QU Jiang-man; XUE Zhan-pu; JIANG Yan

    2017-01-01

    To deal with the dynamic response problem of offshore wind power tower under the combined action of winds and waves,finite element method is used to analyze the structure and flow field around the outside flange of the segmentation part.The changes of pressure distribution and vorticity about the outside flange are obtained.Focused on the analysis on the change of hydrostatic pressure and temperature of the tower cut surface,contour lines under the combined action of winds and waves are depicted.Results show that the surface of the offshore wind turbine tower presents instable temperature field when it suffers the action of winds and waves loads,the static pressure increases nonlinearly with the increase of altitude,the fluid vorticity around the outside flange follows an parabolic curve approximately.Results provide a reference for the actual monitoring data of the offshore wind turbine tower under the combined action of winds and waves,so as to ensure the normal operation of tower.

  20. Tall Tower Wind Energy Monitoring and Numerical Model Validation in Northern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Koracin, D. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Kaplan, M. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Smith, C. [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCurdy, G. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Wolf, A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCord, T. [Desert Research Inst. (DRI), Las Vegas, NV (United States); King, K. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Belu, R. [Drexel Univ., Philadelphia, PA (United States); Horvath, K. [Croatian Meteorological and Hydrological Service, Zagreb (Croatia)

    2015-10-01

    The main objectives of this project were to conduct a tall-tower and sodar field campaign in complex terrain, investigate wind properties relevant to wind energy assessment, and evaluate high-resolution models with fixed and adaptive grid structures. Two 60-m towers at Virginia Peak ridges near Washoe Valley, Nevada, were instrumented with cup and vane anemometers as well as sonic anemometers, and an acoustic sounder (hereafter sodar) was installed near one of the towers. The towers were located 2,700 m apart with a vertical distance of 140 m elevation between their bases. Each tower had a downhill exposure of rolling complex terrain, with the nearby valley floor 3,200 m to the west and 800 m below the summit. Cup anemometers were installed at both towers at 20, 40, and 60 m, wind vanes at 20 and 60 m, and sonic anemometers at 20 and 60 m. The sodar measurements were nominally provided every 10 m in vertical distance from 40 to 200 m with the quality of the data generally decreasing with height. Surface air temperature, atmospheric pressure, and radiation measurements were conducted at 1.5 m AGL at both of the towers. Although the plan was to conduct a 1-year period of data collection, we extended the period (October 5, 2012 through February 24, 2014) to cover for possible data loss from instrument or communication problems. We also present a preliminary analysis of the towers and sodar data, including a detailed inventory of available and missing data as well as outliers. The analysis additionally includes calculation of the Weibull parameters, turbulence intensity, and initial computation of wind power density at various heights.

  1. Trends, Opportunities, and Challenges for Tall Wind Turbine and Tower Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, Eric; Roberts, Owen; Dykes, Katherine

    2017-06-28

    This presentation summarizes recent analysis focused on characterizing the opportunity for Tall Wind technologies generally and for tall tower technologies specifically. It seeks to illuminate and explain the concept of Tall Wind, its impact on the wind industry to date, and the potential value of Tall Wind in the future. It also explores the conditions and locations under which the impacts of Tall Wind offer the most significant potential to increase wind technology performance. In addition, it seeks to examine the status of tall tower technology as a key sub-component of Tall Wind, focusing on the potential for continued innovation in tubular steel wind turbine towers and the status and potential for a select set of alternative tall tower technologies.

  2. Wind Turbine Tower Vibration Modeling and Monitoring by the Nonlinear State Estimation Technique (NSET

    Directory of Open Access Journals (Sweden)

    Peng Guo

    2012-12-01

    Full Text Available With appropriate vibration modeling and analysis the incipient failure of key components such as the tower, drive train and rotor of a large wind turbine can be detected. In this paper, the Nonlinear State Estimation Technique (NSET has been applied to model turbine tower vibration to good effect, providing an understanding of the tower vibration dynamic characteristics and the main factors influencing these. The developed tower vibration model comprises two different parts: a sub-model used for below rated wind speed; and another for above rated wind speed. Supervisory control and data acquisition system (SCADA data from a single wind turbine collected from March to April 2006 is used in the modeling. Model validation has been subsequently undertaken and is presented. This research has demonstrated the effectiveness of the NSET approach to tower vibration; in particular its conceptual simplicity, clear physical interpretation and high accuracy. The developed and validated tower vibration model was then used to successfully detect blade angle asymmetry that is a common fault that should be remedied promptly to improve turbine performance and limit fatigue damage. The work also shows that condition monitoring is improved significantly if the information from the vibration signals is complemented by analysis of other relevant SCADA data such as power performance, wind speed, and rotor loads.

  3. 78 FR 10210 - Utility Scale Wind Towers From China and Vietnam

    Science.gov (United States)

    2013-02-13

    ... wind towers. Background The Commission instituted these investigations effective December 29, 2011...)] Utility Scale Wind Towers From China and Vietnam Determinations On the basis of the record \\1\\ developed... with material injury by reason of imports of utility scale wind towers from China and Vietnam, provided...

  4. Evaluation of dynamic response for monopole and hybrid wind mill tower

    Science.gov (United States)

    Shah, Hemal J.; Desai, Atul K.

    2017-07-01

    The wind mill towers are constructed using monopoles or lattice type tower. As the height of tower increases it gives more power but it becomes uneconomical, so in the present research work innovative wind mill tower such as combination of monopole and lattice tower is analyzed using FEM software. When the tall structures are constructed on soft soil it becomes dynamically sensitive so 3 types of soil such as hard, medium and soft soil is also modeled and the innovative tower is studied for different operating frequencies of wind turbine. From study it is concluded that the innovative tower will reduce resonance condition considering soil structure interaction.

  5. Probabilistic Capacity Assessment of Lattice Transmission Towers under Strong Wind

    Directory of Open Access Journals (Sweden)

    Wei eZhang

    2015-10-01

    Full Text Available Serving as one key component of the most important lifeline infrastructure system, transmission towers are vulnerable to multiple nature hazards including strong wind and could pose severe threats to the power system security with possible blackouts under extreme weather conditions, such as hurricanes, derechoes, or winter storms. For the security and resiliency of the power system, it is important to ensure the structural safety with enough capacity for all possible failure modes, such as structural stability. The study is to develop a probabilistic capacity assessment approach for transmission towers under strong wind loads. Due to the complicated structural details of lattice transmission towers, wind tunnel experiments are carried out to understand the complex interactions of wind and the lattice sections of transmission tower and drag coefficients and the dynamic amplification factor for different panels of the transmission tower are obtained. The wind profile is generated and the wind time histories are simulated as a summation of time-varying mean and fluctuating components. The capacity curve for the transmission towers is obtained from the incremental dynamic analysis (IDA method. To consider the stochastic nature of wind field, probabilistic capacity curves are generated by implementing IDA analysis for different wind yaw angles and different randomly generated wind speed time histories. After building the limit state functions based on the maximum allowable drift to height ratio, the probabilities of failure are obtained based on the meteorological data at a given site. As the transmission tower serves as the key nodes for the power network, the probabilistic capacity curves can be incorporated into the performance based design of the power transmission network.

  6. A tall tower study of Missouri winds

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Neil I. [Department of Soil, Environmental and Atmospheric Sciences, 332 ABNR Building, University of Missouri, Columbia, MO 65211 (United States)

    2011-01-15

    This paper summarizes the results of a study of wind speeds observed at heights up to 150 m above ground level around Missouri. This is an amalgamation of four projects that allowed a total of eleven tall communication towers to be instrumented with wind observation equipment across the State of Missouri. This provided an assessment of the wind resource and the characteristics of the seasonal and diurnal cycles of wind in different areas of Missouri at the heights of utility scale wind turbines. Comparisons were also made to wind speeds predicted at these levels from a previously published wind map. The main finding was that the observed winds at each tower were smaller than those presented in the wind map. The discrepancy is most likely to be due to underestimation of the surface roughness and turbulence leading to an overestimation of near-surface wind shear. However, the wind shear, as expressed by the shear parameter was consistently greater than the 'standard' value of 1.4. The reconciliation of these two apparently contradictory findings is that the shear varies with the height at which it is measured. In wind resource assessment, wind shear is usually observed below 50 m and is tacitly assumed to be constant with height when used to extrapolate winds to higher levels. The author advocates the use of the friction velocity as a measure of shear in wind power applications in preference to the shear parameter that is usually used. This is because the shear parameter has a velocity bias that can also manifest as a bias with height or season. As wind power resource assessment is starting to use taller towers than the standard 50 m, intercomparison of site resources and extrapolation to turbine heights can be compromised if the shear parameter is used. (author)

  7. Wind-induced response of CN-Tower: comparison of model and full scale

    International Nuclear Information System (INIS)

    Monbaliu, J.; Ruigrok, C.; Isyumov, N.

    1985-01-01

    The approximately 555-m high CN Communications Tower in Toronto has now been operational for nearly a decade. The action of wind on this tower was extensively tested at the Boundary Layer Wind Tunnel Laboratory during the design of the tower. This study provided information on the overall wind loads and responses of the structure, the action of wind on various components, and its effects on the tower performance including transmission quality. A program of monitoring and recording the wind induced response and various meteorological data was started in 1977. This paper presents some results of that program and makes comparisons with wind tunnel model data. (author)

  8. Improved reliability of wind turbine towers with active tuned mass dampers (ATMDs)

    Science.gov (United States)

    Fitzgerald, Breiffni; Sarkar, Saptarshi; Staino, Andrea

    2018-04-01

    Modern multi-megawatt wind turbines are composed of slender, flexible, and lightly damped blades and towers. These components exhibit high susceptibility to wind-induced vibrations. As the size, flexibility and cost of the towers have increased in recent years, the need to protect these structures against damage induced by turbulent aerodynamic loading has become apparent. This paper combines structural dynamic models and probabilistic assessment tools to demonstrate improvements in structural reliability when modern wind turbine towers are equipped with active tuned mass dampers (ATMDs). This study proposes a multi-modal wind turbine model for wind turbine control design and analysis. This study incorporates an ATMD into the tower of this model. The model is subjected to stochastically generated wind loads of varying speeds to develop wind-induced probabilistic demand models for towers of modern multi-megawatt wind turbines under structural uncertainty. Numerical simulations have been carried out to ascertain the effectiveness of the active control system to improve the structural performance of the wind turbine and its reliability. The study constructs fragility curves, which illustrate reductions in the vulnerability of towers to wind loading owing to the inclusion of the damper. Results show that the active controller is successful in increasing the reliability of the tower responses. According to the analysis carried out in this paper, a strong reduction of the probability of exceeding a given displacement at the rated wind speed has been observed.

  9. Tall towers for large wind turbines. Report from Vindforsk project V-342

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Staffan; Lyrner, Tomas; Hassanzadeh, Manouchehr; Stalin, Thomas; Johansson, John

    2010-07-15

    The general rule of thumb has been to furnish a wind turbine with a tower as tall as the turbine diameter, with deviations downwards for high wind speed sites. In this report the statement is questioned, with special emphasis for wind turbines sited in forests. The aim of this project was to propose and calculate candidate types of tall towers for on-shore wind turbines in the 3 - 5 MW range, with special reference to siting in forests with a representative wind shear. During the project this scope has been more precisely defined to study 3 and 5 MW wind turbines with hub heights of 80 - 175 meters featuring the following tower solutions: 1. Steel shell tower designed in a conventional way with flanges and both longitudinal and transverse welds. 2. Steel shell tower with bolted friction joints only. 3. Concrete tower with pretensioned steel tendons. 4. Hybrid tower with a lower concrete part and an upper part built as a conventional steel shell. 5. Lattice tower. 6. Wooden tower. During the execution of the project the design of a total of 42 towers was outlined and calculated. Today the welded steel shell tower dominates the wind turbine market. Larger turbines and higher hub heights result in larger optimal tower base diameters. For the road transportation there are limitations due to bridges and other obstacles. In Sweden the limit for transports with special permits in general maximizes the diameter to 4,5 metres. To some extent it is still technically possible to build towers with a less than optimal diameter, but due to the high mass and the large wall thickness they tend to be uneconomical in comparison with other alternatives above a hub height of roughly 100 metres. In this report welded steel shell towers were outlined for 3 MW turbines up to a hub height of 150 metres whereas the limit for the 5 MW towers was 100 metres. When diameter restrictions tend to make welded towers uneconomical, the next logical choice is steel shell towers with bolted friction

  10. Wind-induced transmission tower foundation loads. A field study-design code comparison

    Energy Technology Data Exchange (ETDEWEB)

    Savory, E. [Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ont. (Canada); Parke, G.A.R.; Disney, P.; Toy, N. [School of Engineering, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2008-06-15

    This paper presents a comparison between the wind-induced foundation loads measured on a type L6 transmission line tower during a field study in the UK and those computed using the UK Code of Practice for lattice tower and transmission line design (BS8100). In this work, the Code provisions have been generalised to give the wind-induced strain in each of the tower legs immediately above the foundation as a function of wind direction and wind speed at the top of the tower. The complete data set from the field monitoring has been decomposed to provide a similar formulation for comparison purposes. The analysis shows excellent agreement between the Code calculations and the measured results, within the overall accuracy of the field data. This indicates that, at least for the tower type examined here, the existing design Code provides a reliable transformation of the local wind speed at the top of the tower into tension and compression loads on the foundations. (author)

  11. Summary of tower designs for large horizontal axis wind turbines

    Science.gov (United States)

    Frederick, G. R.; Savino, J. M.

    1986-01-01

    Towers for large horizontal axis wind turbines, machines with a rotor axis height above 30 meters and rated at more than 500 kW, have varied in configuration, materials of construction, type of construction, height, and stiffness. For example, the U.S. large HAWTs have utilized steel truss type towers and free-standing steel cylindrical towers. In Europe, the trend has been to use only free-standing and guyed cylindrical towers, but both steel and reinforced concrete have been used as materials of construction. These variations in materials of construction and type of construction reflect different engineering approaches to the design of cost effective towers for large HAWTs. Tower designs are the NASA/DOE Mod-5B presently being fabricated. Design goals and requirements that influence tower configuration, height and materials are discussed. In particular, experiences with United States large wind turbine towers are elucidated. Finally, current trends in tower designs for large HAWTs are highlighted.

  12. Hexcrete Tower for Harvesting Wind Energy at Taller Hub Heights - Budget Period 2

    Energy Technology Data Exchange (ETDEWEB)

    Sritharan, Sri [Iowa State Univ., Ames, IA (United States)

    2017-05-01

    Interest in designing taller towers for wind energy production in the United States (U.S.) has been steadily growing. In May 2015, it was revealed that taller towers will make wind energy production a reality in all 50 states, including some states that have nearly zero renewables in their energy portfolio. Facilitating wind energy production feasibility in all 50 states will no doubt contribute to increasing the electricity produced by wind from 4.5% in 2013 to a targeted scenario of 35% by 2050 in the Wind Vision report. This project focuses on the Hexcrete tower concept developed for tall towers using High Strength Concrete (HSC) and/or Ultra-High Performance Concrete (UHPC). Among other benefits, the Hexcrete concept overcomes transportation and logistical challenges, thus facilitating construction of towers with hub heights of 100-m (328-ft) and higher. The goal of this project is to facilitate widespread deployment of Hexcrete towers for harvesting wind energy at 120 to 140-m (394 to 459-ft) hub heights and reduce the Levelized Cost of Energy (LCOE) of wind energy production in the U.S. The technical scope of the project includes detailed design and optimization of at least three wind turbine towers using the Hexcrete concept together with experimental validation and LCOE analyses and development of a commercialization plan.

  13. Wind towers architecture, climate and sustainability

    CERN Document Server

    Bahadori, Mehdi N; Sayigh, Ali

    2014-01-01

    This book offers a holistic treatment of wind towers, from their underlying scientific principles to design and operation. Includes suggestions for optimization based on the authors' own research findings from recent analytical studies.

  14. Investigation of Airflow Patterns in a New Design of Wind Tower with a Wetted Surface

    Directory of Open Access Journals (Sweden)

    Madjid Soltani

    2018-04-01

    Full Text Available Passive cooling systems, such as wind towers, can help to reduce energy consumption in buildings and at the same time reduce greenhouse gas (GHG emissions. Wind towers can naturally ventilate buildings and also can create enhanced thermal comfort for occupants during the warm months. This study proposes a modern wind tower design with a moistened pad. The new design includes a fixed column, a rotating and movable head, an air opening with a screen, and two windows at the end of the column. The wind tower can be installed on roof-tops to take advantage of ambient airflow. The wind tower’s head can be controlled manually or automatically to capture optimum wind velocity based on desired thermal condition. To maximize its performance, a small pump was considered to circulate and spray water on an evaporative cooling pad. A computational fluid dynamics (CFD simulation of airflow around and inside the proposed wind tower is conducted to analyze the ventilation performance of this new design of wind tower. Thereby, the velocity, total pressure, and pressure coefficient distributions around and within the wind tower for different wind velocities are examined. The simulation results illustrate that the new wind tower design with a moistened pad can be a reasonable solution to improve naturally the thermal comfort of buildings in hot and dry climates.

  15. Research on Condition Assessment Method of Transmission Tower Under the Action of Strong Wind

    Science.gov (United States)

    Huang, Ren-mou; An, Li-qiang; Zhang, Rong-lun; Wu, Jiong; Liang, Ya-feng

    2018-03-01

    Transmission towers are often subjected to the external damage of severe weather like strong wind and so on, which may cause the collapse due to the yield and fracture of the tower material. Aiming this issue, an assessment method was proposed in this paper to assess the operation condition of transmission towers under strong wind. With a reasonable assess index system established firstly, then the internal force of the tower material was solved and its stability was determined through the mechanical analysis of the transmission tower finite element model. Meanwhile, the condition risk level of the tower was finally determined by considering the difference among the influences of other factors like corrosion and loose of members, slope on the transmission tower through the analytic hierarchy process. The assessment method was applied to assess the wind-induced collapse of towers in 110kV Bao Yi II line in Wenchang City, Hainan Province, of which the result proves the method can assess the condition of transmission tower under strong wind and of guiding significance for improving the windproof capability of transmission towers.

  16. Wind Climate Analyses for a 61-M Tower in the Southeast

    International Nuclear Information System (INIS)

    Weber, A.H.

    2003-01-01

    The Savannah River Technology Center's (SRTC) Atmospheric Technologies Group (ATG) has operated nine 61-m tower sites including the Central Climatology (CC) tower which is located near the center of the Savannah River Site (SRS) since 1985. Data from the weather instruments on this tower have provided answers to questions involving risk analyses, dose studies, forecast verifications, and wind/temperature conditions during extreme events and planned tests. Most recently, data from these towers are being used for initial and boundary conditions for computationally intensive numerical simulations using mesoscale forecasting models that are run on a three-hourly basis by ATG for SRS and the surrounding vicinity. We found that a series of wind roses based on relatively short time scales (from two weeks to one hour) were a convenient method to depict the predominant wind speeds and directions at anemometer sites in the Southeast operated by the NWS. That report also revealed some interesting spatial and temporal relationships among thirteen NWS stations in the Carolinas, Georgia, and Florida. Our study here will focus on the CC tower to show changes in the wind speed and direction distributions with height during diurnal and annual cycles. This study will concentrate on mean wind speed and direction statistics

  17. Predicting wind shear effects: A study of Minnesota wind data collected at heights up to 70 meters

    Energy Technology Data Exchange (ETDEWEB)

    Artig, R. [Minnesota Dept. of Public Service, St. Paul, MN (United States)

    1997-12-31

    The Minnesota Department of Public Service (DPS) collects wind data at carefully selected sites around the state and analyzes the data to determine Minnesota`s wind power potential. DPS recently installed advanced new monitoring equipment at these sites and began to collect wind data at 30, 50, and 70 meters above ground level, with two anemometers at each level. Previously, the Department had not collected data at heights above ground level higher than 30 meters. DPS also, with the U.S. Department of Energy (DOE), installed four sophisticated monitoring sites as part of a Tall Tower Wind Shear Study that is assessing the effects of wind shear on wind power potential. At these sites, wind data are being collected at the 10, 30, 40, 50, 60, and 70 meter heights. This paper presents the preliminary results of the analysis of wind data from all sites. These preliminary results indicate that the traditional 1/7 power law does not effectively predict wind shear in Minnesota, and the result is an underestimation of Minnesota`s wind power potential at higher heights. Using a power factor of 1/5 or 1/4 may be more accurate and provide sound justification for installing wind turbines on taller towers in Minnesota.

  18. Heat Transfer Enhancement of the Air-Cooling Tower with Rotating Wind Deflectors under Crosswind Conditions

    Directory of Open Access Journals (Sweden)

    Xueping Du

    2018-04-01

    Full Text Available To investigate the effect of wind deflectors on air flow and heat transfer performance of an air-cooling tower under crosswind conditions, an experimental system based on a surface condenser aluminum exchanger-type indirect air-cooling tower is established at a 1:100 proportional reduction. A 3-D computational fluid dynamics simulation model is built to study the air flow and temperature fields. The air flow rate into the cooling tower and the heat transfer rate of the radiators are used to evaluate cooling performance. Rotating wind deflectors are adopted to reduce the influence of crosswind on the cooling tower performance. The effects of the rotating wind deflectors on the thermal-hydraulic characteristics of the air-cooling tower under different environmental crosswind speeds are studied. Results indicate that the wind direction in the tower reverses as the rotating speed of the wind deflectors increases. The thermal performance of an air-cooling tower under crosswind conditions can be improved by using rotating wind deflectors. The heat transfer rate of a cooling tower with eight wind deflectors begins to increase when the rotating speed exceeds 2 r/min.

  19. Modal Analysis on Fluid-Structure Interaction of MW-Level Vertical Axis Wind Turbine Tower

    Directory of Open Access Journals (Sweden)

    Tan Jiqiu

    2014-05-01

    Full Text Available In order to avoid resonance problem of MW-level vertical axis wind turbine induced by wind, a flow field model of the MW-level vertical axis wind turbine is established by using the fluid flow control equations, calculate flow’s velocity and pressure of the MW-level vertical axis wind turbine and load onto tower’s before and after surface, study the Modal analysis of fluid-structure interaction of MW-level vertical axis wind turbine tower. The results show that fluid-structure interaction field of MW- level vertical axis wind turbine tower has little effect on the modal vibration mode, but has a great effect on its natural frequency and the maximum deformation, and the influence will decrease with increasing of modal order; MW-level vertical axis wind turbine tower needs to be raised the stiffness and strength, its structure also needs to be optimized; In the case of satisfy the intensity, the larger the ratio of the tower height and wind turbines diameter, the more soft the MW-level vertical axis wind turbine tower, the lower its frequency.

  20. Wind dependence on the flow rate in a natural draught cooling tower

    International Nuclear Information System (INIS)

    Baer, E.; Ernst, G.; Wurz, D.

    1981-01-01

    The efficiency of a natural draught cooling tower depends, among other things, on the effect of the wind on the flow in the tower stack. Determinations were made on a natural draught wet cooling tower 100 metres high, for the purpose of studying this effects. As characteristic quantity, a typical height was determined, the values of which were worked out from the results of the measurements. The efficiency of the stack is affected the most in the case of average wind velocities (when the velocity of the wind is about equal to the mean velocity of the plume). This effect diminishes when the velocity of the wind increases. In the case of average wind velocities, the direction of the wind has an effect, owing to the neighbouring buildings; for slightly greater wind velocities, no effect could be found [fr

  1. Wind turbine generator application places unique demands on tower design and materials

    Science.gov (United States)

    Kita, J. P.

    1978-01-01

    The most relevant contractual tower design requirements and goal for the Mod-1 tower are related to steel truss tower construction, cost-effective state-of-the-art design, a design life of 30 years, and maximum wind conditions of 120 mph at 30 feet elevation. The Mod-1 tower design approach was an iterative process. Static design loads were calculated and member sizes and overall geometry chosen with the use of finite element computer techniques. Initial tower dynamic characteristics were then combined with the dynamic properties of the other wind turbine components, and a series of complex dynamic computer programs were run to establish a dynamic load set and then a second tower design.

  2. Detection of Excessive Wind Turbine Tower Oscillations Fore-Aft and Sideways

    DEFF Research Database (Denmark)

    Knudsen, Torben; Bak, Thomas; Tabatabaeipour, Seyed Mojtaba

    2012-01-01

    Fatigue loads are important for the overall cost of energy from a wind turbine. Loading on the tower is one of the more important loads, as the tower is an expensive component. Consequently, it is important to detect tower loads, which are larger than necessary. This paper deals with both fore......-aft and sideways tower oscillations. Methods for estimation of the amplitude and detection of the cause for vibrations are developed. Good results are demonstrated for real data from modern multi mega watt turbines. It is shown that large oscillations can be detected and that the method can discriminate between...... wind turbulence and unbalanced rotor....

  3. Wind Shear Characteristics at Central Plains Tall Towers (presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, M.; Elliott, D.

    2006-06-05

    The objectives of this report are: (1) Analyze wind shear characteristics at tall tower sites for diverse areas in the central plains (Texas to North Dakota)--Turbines hub heights are now 70-100 m above ground and Wind measurements at 70-100+ m have been rare. (2) Present conclusions about wind shear characteristics for prime wind energy development regions.

  4. 78 FR 11146 - Utility Scale Wind Towers From the People's Republic of China: Antidumping Duty Order

    Science.gov (United States)

    2013-02-15

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-981] Utility Scale Wind Towers...''), the Department is issuing an antidumping duty order on utility scale wind towers (``wind towers...) 482-3936, or (202) 482-4852, respectively. SUPPLEMENTARY INFORMATION: Background In accordance with...

  5. Tower Based Load Measurements for Individual Pitch Control and Tower Damping of Wind Turbines

    International Nuclear Information System (INIS)

    Kumar, A A; Hugues-Salas, O; Savini, B; Keogh, W

    2016-01-01

    The cost of IPC has hindered adoption outside of Europe despite significant loading advantages for large wind turbines. In this work we presented a method for applying individual pitch control (including for higher-harmonics) using tower-top strain gauge feedback instead of blade-root strain gauge feedback. Tower-top strain gauges offer hardware savings of approximately 50% in addition to the possibility of easier access for maintenance and installation and requiring a less specialised skill-set than that required for applying strain gauges to composite blade roots. A further advantage is the possibility of using the same tower-top sensor array for tower damping control. This method is made possible by including a second order IPC loop in addition to the tower damping loop to reduce the typically dominating 3P content in tower-top load measurements. High-fidelity Bladed simulations show that the resulting turbine spectral characteristics from tower-top feedback IPC and from the combination of tower-top IPC and damping loops largely match those of blade-root feedback IPC and nacelle- velocity feedback damping. Lifetime weighted fatigue analysis shows that the methods allows load reductions within 2.5% of traditional methods. (paper)

  6. Impact of Wind Shear and Tower Shadow Effects on Power System with Large Scale Wind Power Penetration

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Chen, Zhe

    2011-01-01

    presents a simulation model of a variable speed wind farm with permanent magnet synchronous generators (PMSGs) and fullscale back-to-back converters in the simulation tool of DIgSILENT/PowerFactory. In this paper, the impacts of wind shear and tower shadow effects on the small signal stability of power......Grid connected wind turbines are fluctuating power sources due to wind speed variations, the wind shear and the tower shadow effects. The fluctuating power may be able to excite the power system oscillation at a frequency close to the natural oscillation frequency of a power system. This paper...... systems with large scale wind power penetrations are investigated during continuous operation based on the wind turbine model and the power system model....

  7. Wind tower with vertical rotors

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, A

    1978-08-03

    The invention concerns a wind tower with vertical rotors. A characteristic is that the useful output of the rotors is increased by the wind pressure, which is guided to the rotors at the central opening and over the whole height of the structure by duct slots in the inner cells. These duct slots start behind the front nose of the inner cell and lead via the transverse axis of the pillar at an angle into the space between the inner cells and the cell body. This measure appreciably increases the useful output of the rotors, as the rotors do not have to provide any displacement work from their output, but receive additional thrust. The wind pressure pressing from inside the rotor and accelerating from the outside produces a better outflow of the wind from the power plant pillar with only small tendency to turbulence, which appreciably improves the effect of the adjustable turbulence smoothers, which are situated below the rotors over the whole height.

  8. Experimental evaluation of the wind effects on an operating power transmission tower

    Directory of Open Access Journals (Sweden)

    Hermes Carvalho

    Full Text Available Abstract Static and dynamic effects on power transmission towers can be evaluated by methodologies available in codes, which suggest the use of linear static analysis. By using numerical simulations, it is possible to observe the strong influence of the geometric nonlinear behavior of transmission cables. Dynamic effects also strongly influence this behavior, with the possibility of resonance between the cables and the structure, but up to the moment, the existent analysis procedures have not been completely validated on an experimental basis. In order to validate a complete analysis methodology, experimental procedures are proposed for a suspension tower of a 138kV transmission line in use. A tridimensional anemometer was installed on this structure in order to measure the values and directions of wind speeds. Simultaneous strain values were collected on the main elements of the tower through optical extensometers. Optical sensor technology with Fiber Bragg Gratings was used, due to the characteristic of immunity to the electromagnetic field occasioned by high electric currents. The string swing angle was evaluated through a high-resolution camera and a tridimensional accelerometer. With this instrumentation, it is possible to create a complete database that correlates wind speeds with the responses of the structural set. At the moment, 5 months of data have been collected and the instrumentation is in the final testing phase and synchronized. After this step, real-time measurements will be performed.

  9. Validation of Simplified Load Equations Through Loads Measurement and Modeling of a Small Horizontal-Axis Wind Turbine Tower

    Energy Technology Data Exchange (ETDEWEB)

    Dana, Scott [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Van Dam, Jeroen J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Damiani, Rick R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-24

    As part of an ongoing effort to improve the modeling and prediction of small wind turbine dynamics, the National Renewable Energy Laboratory (NREL) tested a small horizontal-axis wind turbine in the field at the National Wind Technology Center. The test turbine was a 2.1-kW downwind machine mounted on an 18-m multi-section fiberglass composite tower. The tower was instrumented and monitored for approximately 6 months. The collected data were analyzed to assess the turbine and tower loads and further validate the simplified loads equations from the International Electrotechnical Commission (IEC) 61400-2 design standards. Field-measured loads were also compared to the output of an aeroelastic model of the turbine. In particular, we compared fatigue loads as measured in the field, predicted by the aeroelastic model, and calculated using the simplified design equations. Ultimate loads at the tower base were assessed using both the simplified design equations and the aeroelastic model output. The simplified design equations in IEC 61400-2 do not accurately model fatigue loads and a discussion about the simplified design equations is discussed.

  10. Mitigation of mechanical loads of NREL 5MW wind turbine tower

    International Nuclear Information System (INIS)

    Nam, Yoonsu; Im, Chang Hee

    2012-01-01

    As the size of a wind turbine increases, the mechanical structure has to have an increasing mechanical stiffness that is sufficient to withstand mechanical fatigue loads over a lifespan of more than 20 years. However, this leads to a heavier mechanical design, which means a high material cost during wind turbine manufacturing. Therefore, lightweight design of a wind turbine is an important design constraint. Usually, a lightweight mechanical structure has low damping. Therefore, if it is subjected to a disturbance, it will oscillate continuously. This study deals with the active damping control of a wind turbine tower. An algorithm that mitigates the mechanical loads of a wind turbine tower is introduced. The effectiveness of this algorithm is verified through a numerical simulation using GH Bladed, which is a commercial aero elastic code for wind turbines

  11. Collapse and pull - down analysis of high voltage electricity transmission towers subjected to cyclonic wind

    International Nuclear Information System (INIS)

    Ahmed, Ammar; Arthur, Craig; Edwards, Mark

    2010-01-01

    Bulk electricity transmission lines are linear assets that can be very exposed to wind effects, particularly where they traverse steep topography or open coastal terrain in cyclonic regions. Interconnected nature of the lattice type towers and conductors also, present complex vulnerabilities. These relate to the direction of wind attack to the conductors and the cascading failure mechanisms in which the failure of a single tower has cascading effects on neighbouring towers. Such behaviour is exacerbated by the finely tuned nature of tower design which serves to minimize cost and reserve strength at design wind speeds. There is a clear need to better quantify the interdependent vulnerabilities of these critical infrastructure assets in the context of the severe wind hazard. This paper presents a novel methodology developed for the Critical Infrastructure Protection Modelling and Analysis (CIPMA) capability for assessing local wind speeds and the likelihood of tower failure for a range of transmission tower and conductor types. CIPMA is a program managed by the Federal Attorney-General's Department and Geoscience Australia is leading the technical development. The methodology then involves the development of heuristically derived vulnerability models that are consistent with Australian industry experience and full-scale static tower testing results, considering isolated tower loss along with three interdependent failure mechanisms to give overall likelihoods of failure.

  12. Validation of SWAY Wind Turbine Response in FAST, with a Focus on the Influence of Tower Wind Loads: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Koh, J. H.; Robertson, A.; Jonkman, J.; Driscoll, R.; Yin Kwee Ng, E.

    2015-04-23

    Need to modify simulated system behavior to the measured data, but the tower wind loads improved the comparison for nonoperating conditions. the SWAY system in both turbine operating and nonoperating conditions. Mixed results were observed when comparing the simulated system behavior to the measured data, but the tower wind loads improved the comparison for nonoperating conditions. without the new tower-load capability to examine its influence on the response characteristics of the system. This is important in situations when the turbine is parked in survival conditions. The simulation results were then compared to measured data from the SWAY system in both turbine operating and nonoperating conditions. Mixed results were observed when comparing the simulated system behavior to the measured data, but the tower wind loads improved the comparison for nonoperating conditions.

  13. Coherence Effects on the Power and Tower Loads of a 7 × 2 MW Multi-Rotor Wind Turbine System

    Directory of Open Access Journals (Sweden)

    Shigeo Yoshida

    2016-09-01

    Full Text Available A multi-rotor system (MRS, in which multiple wind turbines are placed on one tower, is a promising concept for super-large wind turbines at over 10 MW due to the cost and weight advantages. The coherence effects on an MRS were investigated in this study. Although a wide range of coherences were measured so far, a decay constant of C = 12 is recommended in the IEC61400-1 standard. Dynamic simulations were performed for a 14-MW MRS, which consists of seven 2-MW turbines and includes wind models with three different coherences. Although the results show that a larger coherence increases the output power and the collective loads due to tower base fore-aft bending, it reduces the differential loads due to tower-base torque and tower-top nodding. The most significant case is the fatigue damage due to tower base fore-aft bending, which was more than doubled between the decay constants of C = 6 and C = 12. The present results indicate that the coherence should be defined carefully in the design of large-scale MRSs because its effect on them is not straightforward.

  14. Average wind statistics for SRP area meteorological towers

    International Nuclear Information System (INIS)

    Laurinat, J.E.

    1987-01-01

    A quality assured set of average wind Statistics for the seven SRP area meteorological towers has been calculated for the five-year period 1982--1986 at the request of DOE/SR. A Similar set of statistics was previously compiled for the years 1975-- 1979. The updated wind statistics will replace the old statistics as the meteorological input for calculating atmospheric radionuclide doses from stack releases, and will be used in the annual environmental report. This report details the methods used to average the wind statistics and to screen out bad measurements and presents wind roses generated by the averaged statistics

  15. Transient Simulation of Wind Turbine Towers under Lightning Stroke

    Directory of Open Access Journals (Sweden)

    Xiaoqing Zhang

    2013-01-01

    Full Text Available A simulation algorithm is proposed in this paper for lightning transient analysis of the wind turbine (WT towers. In the proposed algorithm, the tower body is first subdivided into a discrete multiconductor system. A set of formulas are given to calculate the electrical parameters of the branches in the multiconductor system. By means of the electrical parameters, each branch unit in the multiconductor system is replaced as a coupled π-type circuit and the multiconductor system is converted into a circuit model. Then, the lightning transient responses can be obtained in different parts on the tower body by solving the circuit equations of the equivalent discretization network. The laboratory measurement is also made by a reduced-scale tower for checking the validity of the proposed algorithm.

  16. On Using Wind Speed Preview to Reduce Wind Turbine Tower Oscillations

    DEFF Research Database (Denmark)

    Kristalny, Maxim; Madjidian, Daria; Knudsen, Torben

    2013-01-01

    We investigate the potential of using previewed wind speed measurements for damping wind turbine fore-aft tower oscillations. Using recent results on continuous-time H 2 preview control, we develop a numerically efficient framework for the feedforward controller synthesis. One of the major benefits...... characteristics on the achievable performance and on the required length of preview. We demonstrate the importance of accounting for the distortion in the controller synthesis and quantify the potential benefits of using previewed information by means of simulations based on real-world turbine data....

  17. Vibration analysis of three guyed tower designs for intermediate size wind turbines

    Science.gov (United States)

    Christie, R. J.

    1982-01-01

    Three guyed tower designs were analyzed for intermediate size wind turbines. The four lowest natural frequencies of vibration of the three towers concepts were estimated. A parametric study was performed on each tower to determine the effect of varying such tower properties as the inertia and stiffness of the tower and guys, the inertia values of the nacelle and rotor, and the rotational speed of the rotor. Only the two lowest frequencies were in a range where they could be excited by the rotor blade passing frequencies. There two frequencies could be tuned by varying the guy stiffness, the guy attachment point on the tower, the tower and mass stiffness, and the nacelle/rotor/power train masses.

  18. The influence and analysis of natural crosswind on cooling characteristics of the high level water collecting natural draft wet cooling tower

    Science.gov (United States)

    Ma, Libin; Ren, Jianxing

    2018-01-01

    Large capacity and super large capacity thermal power is becoming the main force of energy and power industry in our country. The performance of cooling tower is related to the water temperature of circulating water, which has an important influence on the efficiency of power plant. The natural draft counter flow wet cooling tower is the most widely used cooling tower type at present, and the high cooling tower is a new cooling tower based on the natural ventilation counter flow wet cooling tower. In this paper, for high cooling tower, the application background of high cooling tower is briefly explained, and then the structure principle of conventional cooling tower and high cooling tower are introduced, and the difference between them is simply compared. Then, the influence of crosswind on cooling performance of high cooling tower under different wind speeds is introduced in detail. Through analysis and research, wind speed, wind cooling had little impact on the performance of high cooling tower; wind velocity, wind will destroy the tower inside and outside air flow, reducing the cooling performance of high cooling tower; Wind speed, high cooling performance of cooling tower has increased, but still lower than the wind speed.

  19. Performance Evaluation on Transmission Tower-Line System with Passive Friction Dampers Subjected to Wind Excitations

    Directory of Open Access Journals (Sweden)

    Bo Chen

    2015-01-01

    Full Text Available The vibration control and performance evaluation on a transmission-tower line system by using friction dampers subjected to wind excitations are carried out in this study. The three-dimensional finite element (FE model of a transmission tower is firstly constructed. A two-dimensional lumped mass model of a transmission tower is developed for dynamic analysis. The analytical model of transmission tower-line system is proposed by taking the dynamic interaction between the tower and the transmission lines into consideration. The mechanical model of passive friction damper is presented by involving the effects of damper axial stiffness. The equation of motion of the transmission tower-line system incorporated with the friction dampers disturbed by wind excitations is established. A real transmission tower-line system is taken as an example to examine the feasibility and reliability of the proposed control approach. An extensive parameter study is carried out to find the optimal parameters of friction damper and to assess the effects of slipping force axial stiffness and hysteresis loop on control performance. The work on an example structure indicates that the application of friction dampers with optimal parameters could significantly reduce wind-induced responses of the transmission tower-line system.

  20. EFFECT OF THE FILL VENTILATION WINDOW ON PERFORMANCE OF A NATURAL DRAFT COOLING TOWER SUBJECTED TO CROSS-WINDS

    Directory of Open Access Journals (Sweden)

    K. V. Dobrego

    2016-01-01

    Full Text Available Various aerodynamic design elements and technics (wind deflectors, wind walls, etc. are utilized for improvement of the thermal efficiency of the natural draft cooling towers, particularly in conditions of cross wind. One of the technical methods, proposed by engineers of Belarus Academy of Sciences, is installation of the ventilation window in the center of the fill. This method is substantiated by the fact that the flow of cooling gas obtains maximum temperature and humidity near the center of the under-fill space of cooling tower and, as a consequence, performs minimal heat exchange. The influence of the fill ventilation window and wind deflectors in the inlet windows of the cooling tower on its thermal performance in condition of cross-wind is investigated in the paper numerically. The cooling tower of the “Woo-Jin” power plant (China 150 m of the height and 114 m of the base diameter was taken as a prototype. The analogy (equivalence between the heat and mass transfer was taken into consideration, which enabled us to consider single-phase flow and perform complicated 3D simulation by using modern personal computers. Heat transfer coefficient for the fill and its hydrodynamic resistance were defined by using actual data on total flow rate in the cooling tower. The numerical model and computational methods were tested and verified in numerous previous works. The non-linear dependence of the thermal performance of the cooling tower on wind velocity (with the minimum in vicinity of Ucr ~ 8 m/s for the simulated system was demonstrated. Calculations show that in the condition of the average wind speed the fill ventilation window doesn’t improve, but slightly decrease (by 3–7 % performance of the cooling tower. Situation changes in the condition of strong winds Ucw > 12 m/s, which are not typical for Belarus. Utilization of airflow deflectors at the inlet windows of cooling tower, conversely, increases thermal performance of the

  1. A Virtual Tool for Minimum Cost Design of a Wind Turbine Tower with Ring Stiffeners

    Directory of Open Access Journals (Sweden)

    Fatih Karpat

    2013-07-01

    Full Text Available Currently, renewable energy resources are becoming more important to reduce greenhouse gas emissions and increase energy efficiency. Researchers have focused on all components of wind turbines to increase reliability and minimize cost. In this paper, a procedure including a cost analysis method and a particle swarm optimization algorithm has been presented to efficiently design low cost steel wind turbine towers. A virtual tool is developed in MATLAB for the cost optimization of wind turbine steel towers with ring stiffeners using a particle swarm optimization algorithm. A wind turbine tower optimization problem in the literature is solved using the developed computer program. In the optimization procedure the optimization results match very well with the optimization results obtained previously. The wall thickness of the shell segments and the dimensions of the ring stiffeners are selected as the design variables, and the limits of the local buckling for the flat ring stiffeners, the local shell buckling limit, the panel ring buckling limit and the limitation of the frequency are considered the design constraints. Numerical examples are presented to understand the impacts of the design variables on the total cost of the wind turbine tower.

  2. Design and Manufacturing of Composite Tower Structure for Wind Turbine Equipment

    Science.gov (United States)

    Park, Hyunbum

    2018-02-01

    This study proposes the composite tower design process for large wind turbine equipment. In this work, structural design of tower and analysis using finite element method was performed. After structural design, prototype blade manufacturing and test was performed. The used material is a glass fiber and epoxy resin composite. And also, sand was used in the middle part. The optimized structural design and analysis was performed. The parameter for optimized structural design is weight reduction and safety of structure. Finally, structure of tower will be confirmed by structural test.

  3. Investigation of Influence Factors of Wind-Induced Buffeting Response of a Six-Tower Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Zhi-Qiang Zhang

    2016-01-01

    Full Text Available This paper presents an investigation of the wind-induced buffeting responses of the Jiashao Bridge, the longest multispan cable-stayed bridge in the world. A three-dimensional finite element model for the Jiashao Bridge is established using the commercial software package ANSYS and a 3D fluctuating wind field is simulated for both bridge deck and towers. A time-domain procedure for analyzing buffeting responses of the bridge is implemented in ANSYS with the aeroelastic effect included. The characteristics of buffeting responses of the six-tower cable-stayed bridge are studied in some detail, focusing on the effects including the difference in the longitudinal stiffness between the side towers and central towers, partially longitudinal constraints between the bridge deck and part of bridge towers, self-excited aerodynamic forces, and the rigid hinge installed in the middle of the bridge deck. The analytical results can provide valuable references for wind-resistant design of multispan cable-stayed bridges in the future.

  4. Dynamics and Control of Lateral Tower Vibrations in Offshore Wind Turbines by Means of Active Generator Torque

    Directory of Open Access Journals (Sweden)

    Zili Zhang

    2014-11-01

    Full Text Available Lateral tower vibrations of offshore wind turbines are normally lightly damped, and large amplitude vibrations induced by wind and wave loads in this direction may significantly shorten the fatigue life of the tower. This paper proposes the modeling and control of lateral tower vibrations in offshore wind turbines using active generator torque. To implement the active control algorithm, both the mechanical and power electronic aspects have been taken into consideration. A 13-degrees-of-freedom aeroelastic wind turbine model with generator and pitch controllers is derived using the Euler–Lagrangian approach. The model displays important features of wind turbines, such as mixed moving frame and fixed frame-defined degrees-of-freedom, couplings of the tower-blade-drivetrain vibrations, as well as aerodynamic damping present in different modes of motions. The load transfer mechanisms from the drivetrain and the generator to the nacelle are derived, and the interaction between the generator torque and the lateral tower vibration are presented in a generalized manner. A three-dimensional rotational sampled turbulence field is generated and applied to the rotor, and the tower is excited by a first order wave load in the lateral direction. Next, a simple active control algorithm is proposed based on active generator torques with feedback from the measured lateral tower vibrations. A full-scale power converter configuration with a cascaded loop control structure is also introduced to produce the feedback control torque in real time. Numerical simulations have been carried out using data calibrated to the referential 5-MW NREL (National Renewable Energy Laboratory offshore wind turbine. Cases of drivetrains with a gearbox and direct drive to the generator are considered using the same time series for the wave and turbulence loadings. Results show that by using active generator torque control, lateral tower vibrations can be significantly mitigated for

  5. Numerical Simulation of Tower Rotor Interaction for Downwind Wind Turbine

    Directory of Open Access Journals (Sweden)

    Isam Janajreh

    2010-01-01

    Full Text Available Downwind wind turbines have lower upwind rotor misalignment, and thus lower turning moment and self-steered advantage over the upwind configuration. In this paper, numerical simulation to the downwind turbine is conducted to investigate the interaction between the tower and the blade during the intrinsic passage of the rotor in the wake of the tower. The moving rotor has been accounted for via ALE formulation of the incompressible, unsteady, turbulent Navier-Stokes equations. The localized CP, CL, and CD are computed and compared to undisturbed flow evaluated by Panel method. The time history of the CP, aerodynamic forces (CL and CD, as well as moments were evaluated for three cross-sectional tower; asymmetrical airfoil (NACA0012 having four times the rotor's chord length, and two circular cross-sections having four and two chords lengths of the rotor's chord. 5%, 17%, and 57% reductions of the aerodynamic lift forces during the blade passage in the wake of the symmetrical airfoil tower, small circular cross-section tower and large circular cross-section tower were observed, respectively. The pronounced reduction, however, is confined to a short time/distance of three rotor chords. A net forward impulsive force is also observed on the tower due to the high speed rotor motion.

  6. Hess Tower field study: sonic measurements at a former building-integrated wind farm site

    Science.gov (United States)

    Araya, Daniel

    2017-11-01

    Built in 2010, Hess Tower is a 29-story office building located in the heart of downtown Houston, TX. Unique to the building is a roof structure that was specifically engineered to house ten vertical-axis wind turbines (VAWTs) to partially offset the energy demands of the building. Despite extensive atmospheric boundary layer (ABL) wind tunnel tests to predict the flow conditions on the roof before the building was constructed, the Hess VAWTs were eventually removed after allegedly one of the turbines failed and fell to the ground. This talk presents in-situ sonic anemometry measurements taken on the roof of Hess Tower at the former turbine locations. We compare this wind field characterization to the ABL wind tunnel data to draw conclusions about building-integrated wind farm performance and prediction capability.

  7. Tornado type wind turbines

    Science.gov (United States)

    Hsu, Cheng-Ting

    1984-01-01

    A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

  8. Tracking of smokestack and cooling tower plumes using wind measurements at different levels

    International Nuclear Information System (INIS)

    Miller, R.L.; Patrinos, A.A.N.

    1980-08-01

    Relationships between cooling tower and smokestack plumes at the Bowen Electric Generating Plant in northwestern Georgia and wind direction measurements at levels from the surface at 850 mb (approx. 1.5 km) are examined. The wind measurements play an important role in estimating plume directions which in turn are utilized to establish control and target (upwind and downwind) areas for a study of plant-induced precipitation modification. Fifty-two plume observations were made during a three week period in December 1979. Results indicate that a windset (4.5 km from the plant) mounted at a level approximating that of the cooling tower plume is a better predictor of plume direction than surface windsets (1.0 km from the plant) or 850 mb level winds. However, an apparent topographical influence on the wind direction measurements at the plume-level windset site somewhat limits its plume tracking capability, at least for ambient winds from the SW quadrant

  9. Kalman filter based data fusion for neutral axis tracking in wind turbine towers

    DEFF Research Database (Denmark)

    Soman, Rohan; Malinowski, Pawel; Ostachowicz, Wieslaw

    2015-01-01

    downtime, hence increasing the availability of the system. The present work is based on the use of neutral axis (NA) for SHM of the structure. The NA is tracked by data fusion of measured yaw angle and strain through the use of Extended Kalman Filter (EKF). The EKF allows accurate tracking even...... in the NA position may be used for detecting and locating the damage. The wind turbine tower has been modelled with FE software ABAQUS and validated on data from load measurements carried out on the 34m high tower of the Nordtank, NTK 500/41 wind turbine....

  10. Wind-break walls with optimized setting angles for natural draft dry cooling tower with vertical radiators

    International Nuclear Information System (INIS)

    Ma, Huan; Si, Fengqi; Kong, Yu; Zhu, Kangping; Yan, Wensheng

    2017-01-01

    Highlights: • Aerodynamic field around dry cooling tower is presented with numerical model. • Performances of cooling deltas are figured out by air inflow velocity analysis. • Setting angles of wind-break walls are optimized to improve cooling performance. • Optimized walls can reduce the interference on air inflow at low wind speeds. • Optimized walls create stronger outside secondary flow at high wind speeds. - Abstract: To get larger cooling performance enhancement for natural draft dry cooling tower with vertical cooling deltas under crosswind, setting angles of wind-break walls were optimized. Considering specific structure of each cooling delta, an efficient numerical model was established and validated by some published results. Aerodynamic fields around cooling deltas under various crosswind speeds were presented, and outlet water temperatures of the two columns of cooling delta were exported as well. It was found that for each cooling delta, there was a difference in cooling performance between the two columns, which is closely related to the characteristic of main airflow outside the tower. Using the present model, air inflow deviation angles at cooling deltas’ inlet were calculated, and the effects of air inflow deviation on outlet water temperatures of the two columns for corresponding cooling delta were explained in detail. Subsequently, at cooling deltas’ inlet along radial direction of the tower, setting angles of wind-break walls were optimized equal to air inflow deviation angles when no airflow separation appeared outside the tower, while equal to zero when outside airflow separation occurred. In addition, wind-break walls with optimized setting angles were verified to be extremely effective, compared to the previous radial walls.

  11. A risk analysis for natural-draught cooling towers under wind load

    International Nuclear Information System (INIS)

    Niemann, H.J.

    1977-01-01

    A satisfactory safety level of natural-draught cooling towers is usually reached by assuming an extreme wind load, for which the probability of being exceeded is very low. Taking into account the dispersion of strength, the relevant extreme wind velocity for the limiting carrying capacity is calculated for a desired probability of failure. Compared with the method of partial safety coefficients, the reliability can be calculated more exactly in this way, even though the probability distribution of the extreme wind velocity must be extrapolated from limited observations. (orig.) [de

  12. 78 FR 17183 - Information Collection: Grey Towers Visitor Comment Card

    Science.gov (United States)

    2013-03-20

    ... DEPARTMENT OF AGRICULTURE Forest Service Information Collection: Grey Towers Visitor Comment Card... request: (1) An extension from the Office of Management and Budget; and (2) to merge the currently approved information collection 0596- 0222, ``Grey Towers Visitor Comment Card'' with 0596-0226, ``Forest...

  13. Model improvements for evaluating the effect of tower tilting on the aerodynamics of a vertical axis wind turbine

    DEFF Research Database (Denmark)

    Wang, K.; Hansen, Martin Otto Laver; Moan, T.

    2015-01-01

    If a vertical axis wind turbine is mounted offshore on a semi-submersible, the pitch motion of the platform will dominate the static pitch and dynamic motion of the platform and wind turbine such that the effect of tower tilting on the aerodynamics of the vertical axis wind turbine should...... be investigated to more accurately predict the aerodynamic loads. This paper proposes certain modifications to the double multiple-streamtube (DMS) model to include the component of wind speed parallel to the rotating shaft. The model is validated against experimental data collected on an H-Darrieus wind turbine...... in skewed flow conditions. Three different dynamic stall models are also integrated into the DMS model: Gormont's model with the adaptation of Strickland, Gormont's model with the modification of Berg and the Beddoes-Leishman dynamic stall model. Both the small Sandia 17m wind turbine and the large DeepWind...

  14. Load-Direction-Derived Support Structures for Wind Turbines: A Lattice Tower Concept and Preparations for Future Certifications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Damiani, Rick R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Struve, Achim [University of Applied Sciences Flensburg; Faber, Torsten [University of Applied Sciences Flensburg; Ummenhofer, Thomas [Karlsruhe Institute of Technology

    2017-11-07

    The call for more cost-effective and environmentally friendly tower concepts is motivated by tower costs [1] and tower CO2-emission contributions [2], which are high relative to the whole wind turbine system. The proposed rotatable tower concept with yaw bearing at the bottom instead of the top of the tower will provide beneficial economic and environmental impacts to the turbine system. This wind alignment capability indicates a load-direction-derived tower design. By combining this approach with a lattice concept, large material and cost savings for the tower can be achieved. This paper presents a way to analyze and verify the proposed design through aero-servo-elastic simulations, which make future certifications of rotatable tower concepts viable. For this reason, the state-of-the-art, open-source lattice-tower finite-element-method (FEM) module SubDyn [10], developed by the National Renewable Energy Laboratory, has been modified to account for arbitrary member cross-sections. Required changes in the beam element stiffness and mass matrix formulation took place according to an energy method [13]. All validated adaptions will be usable within the aero-servo-elastic simulation framework FAST and are also beneficial for other nonrotatable lattice structures.

  15. Evaluation of Offshore Wind Turbine Tower Dynamics with Numerical Analysis

    Directory of Open Access Journals (Sweden)

    Begum Yurdanur Dagli

    2018-01-01

    Full Text Available A dynamic behaviour of a cylindirical wind tower with variable cross section is investigated under environmental and earthquake forces. The ground acceleration term is represented by a simple cosine function to investigate both normal and parallel components of the earthquake motions located near ground surface. The function of earthquake force is simplified to apply Rayleigh’s energy method. Wind forces acting on above the water level and wave forces acting on below this level are utilized in computations considering earthquake effect for entire structure. The wind force is divided into two groups: the force acting on the tower and the forces acting on the rotor nacelle assembly (RNA. The drag and the inertial wave forces are calculated with water particle velocities and accelerations due to linear wave theory. The resulting hydrodynamic wave force on the tower in an unsteady viscous flow is determined using the Morison equation. The displacement function of the physical system in which dynamic analysis is performed by Rayleigh’s energy method is obtained by the single degree of freedom (SDOF model. The equation of motion is solved by the fourth-order Runge–Kutta method. The two-way FSI (fluid-structure interaction technique was used to determine the accuracy of the numerical analysis. The results of computational fluid dynamics and structural mechanics are coupled in FSI analysis by using ANSYS software. Time-varying lateral displacements and the first natural frequency values which are obtained from Rayleigh’s energy method and FSI technique are compared. The results are presented by graphs. It is observed from these graphs that the Rayleigh model can be an alternative way at the prelimanary stage of the structural analysis with acceptable accuracy.

  16. A numerical study on the mechanism and optimization of wind-break structures for indirect air-cooling towers

    International Nuclear Information System (INIS)

    Gu, Hongfang; Wang, Haijun; Gu, Yuqian; Yao, Jianan

    2016-01-01

    Highlights: • Numerical study on the optimization of windbreak structure for IDAC was conducted. • Windbreak wall is the most effective structure but is affected by wind direction. • The louver is next best and it can be flexibly adjusted at the windy conditions. • An optimal louver opening was obtained for achieving a good cooling performance. - Abstract: The heat transfer performance of indirect air-cooling (IDAC) towers in large power stations is sensitive to the ambient wind velocity. To ensure the economic and reliable operation of units under windy conditions, it is important to conduct research on the optimization of different wind-break structures. This paper uses computational fluid dynamics method (CFD) to simulate the heat transfer performance of a 1000 MW IDAC tower power stations with four different wind-break structures namely, cross walls, wind-break walls, cross line-screen, and louvers. The research results show that the order of the effective heat transfer improvement of four wind-break structures is the wind-break, cross wall, line-screen and louvers. The wind-break wall is the most optimal structure, but its performance is strictly influenced by the direction and velocity of the wind, and the cross walls and cross line-screen structure have similar limitation in the practice operation. The louver is installed in each sector, and it is the next best option for increasing the heat transfer performance. It can be flexibly adjusted based on the wind direction and velocity. With the decrease in the louver opening, k, there is a decrease in the heat transfer rate of the windward sectors, and a significant increase in the heat transfer rate of the leeward sectors. Thus the total heat transfer rate of the IDAC tower can be improved tremendously. Based on the analysis of heat transfer and air flow mechanisms, there is an optimal opening, k, which achieves the largest heat transfer performance in an IDAC tower at each wind velocity. This study

  17. The influence of the static wind load concept on the material requirements for reinforced-concrete natural-draught cooling towers

    International Nuclear Information System (INIS)

    Harnach, R.

    1977-01-01

    The natural wind is the decisive risk factor in natural-draught cooling towers; therefore, the establishment of an assumed velocity is indispensable for the safety and reliability of the construction. In the framework of a statistical wind concept, static substitution loads for the assumed dynamic wind pressure have been determined, also including dynamic wind effects and the resonance response of the structure. On this basis, it has been studied how wind loads with different periodicity affect the material requirements of reinforced-concrete natural-draught cooling towers. It is found that the additional steel requirements, related to the total building cost, remain within acceptable limits even for extreme wind loads. (orig.) [de

  18. 2D study of wind forces around multiple cooling towers using ...

    African Journals Online (AJOL)

    A comprehensive numerical study for the determination of wind pressure coefficients on multiple cooling towers by simulating turbulence using Reynolds Averaged Navier-Stokes Equations (RANS) models of Computational Fluid Dynamics techniques (CFD) such as, Standard k −ε , RNG k −ε , Realizable k −ε and Reynolds ...

  19. Design and Evaluation of Glass/epoxy Composite Blade and Composite Tower Applied to Wind Turbine

    Science.gov (United States)

    Park, Hyunbum

    2018-02-01

    In the study, the analysis and manufacturing of small class wind turbine blade was performed. In the structural design, firstly the loading conditions are defined through the load case analysis. The proposed structural configuration of blade has a sandwich type composite structure with the E-glass/Epoxy face sheets and the Urethane foam core for lightness, structural stability, low manufacturing cost and easy manufacturing process. And also, this work proposes a design procedure and results of tower for the small scale wind turbine systems. Structural analysis of blade including load cases, stress, deformation, buckling, vibration and fatigue life was performed using the finite element method, the load spectrum analysis and the Miner rule. Moreover, investigation on structural safety of tower was verified through structural analysis by FEM. The manufacturing of blade and tower was performed based on structural design. In order to investigate the designed structure, the structural tests were conducted and its results were compared with the calculated results. It is confirmed that the final proposed blade and tower meet the design requirements.

  20. Heat Transfer Enhancement of the Air-Cooling Tower with Rotating Wind Deflectors under Crosswind Conditions

    OpenAIRE

    Xueping Du; Dongtai Han; Qiangmin Zhu

    2018-01-01

    To investigate the effect of wind deflectors on air flow and heat transfer performance of an air-cooling tower under crosswind conditions, an experimental system based on a surface condenser aluminum exchanger-type indirect air-cooling tower is established at a 1:100 proportional reduction. A 3-D computational fluid dynamics simulation model is built to study the air flow and temperature fields. The air flow rate into the cooling tower and the heat transfer rate of the radiators are used to e...

  1. Kalman filter based data fusion for neutral axis tracking in wind turbine towers

    Science.gov (United States)

    Soman, Rohan; Malinowski, Pawel; Ostachowicz, Wieslaw; Paulsen, Uwe S.

    2015-03-01

    Wind energy is seen as one of the most promising solutions to man's ever increasing demands of a clean source of energy. In particular to reduce the cost of energy (COE) generated, there are efforts to increase the life-time of the wind turbines, to reduce maintenance costs and to ensure high availability. Maintenance costs may be lowered and the high availability and low repair costs ensured through the use of condition monitoring (CM) and structural health monitoring (SHM). SHM allows early detection of damage and allows maintenance planning. Furthermore, it can allow us to avoid unnecessary downtime, hence increasing the availability of the system. The present work is based on the use of neutral axis (NA) for SHM of the structure. The NA is tracked by data fusion of measured yaw angle and strain through the use of Extended Kalman Filter (EKF). The EKF allows accurate tracking even in the presence of changing ambient conditions. NA is defined as the line or plane in the section of the beam which does not experience any tensile or compressive forces when loaded. The NA is the property of the cross section of the tower and is independent of the applied loads and ambient conditions. Any change in the NA position may be used for detecting and locating the damage. The wind turbine tower has been modelled with FE software ABAQUS and validated on data from load measurements carried out on the 34m high tower of the Nordtank, NTK 500/41 wind turbine.

  2. Modal Analysis on Fluid-Structure Interaction of MW-Level Vertical Axis Wind Turbine Tower

    OpenAIRE

    Tan Jiqiu; Zhong Dingqing; Wang Qiong

    2014-01-01

    In order to avoid resonance problem of MW-level vertical axis wind turbine induced by wind, a flow field model of the MW-level vertical axis wind turbine is established by using the fluid flow control equations, calculate flow’s velocity and pressure of the MW-level vertical axis wind turbine and load onto tower’s before and after surface, study the Modal analysis of fluid-structure interaction of MW-level vertical axis wind turbine tower. The results show that fluid-structure interaction fie...

  3. SIMULATION OF COOLING TOWER AND INFLUENCE OF AERODYNAMIC ELEMENTS ON ITS WORK UNDER CONDITIONS OF WIND

    Directory of Open Access Journals (Sweden)

    K. V. Dobrego

    2014-01-01

    Full Text Available Modern Cooling Towers (CT may utilize different aerodynamic elements (deflectors, windbreak walls etc. aimed to improvement of its heat performance especially at the windy conditions. In this paper the effect of flow rotation in overshower zone of CT and windbreak walls on a capacity of tower evaporating unit in the windy condition is studied numerically. Geometry of the model corresponds to real Woo-Jin Power station, China. Analogy of heat and mass transfer was used that allowed to consider aerodynamic of one-dimension flow and carried out detailed 3D calculations applying modern PC. Heat transfer coefficient of irrigator and its hydrodynamic resistance were established according to experimental data on total air rate in cooling tower. Numerical model is tested and verified with experimental data.Nonlinear dependence of CT thermal performance on wind velocity is demonstrated with the minimum (critical wind velocity at ucr ~ 8 m/s for simulated system. Application of windbreak walls does not change the value of the critical wind velocity, but may improves performance of cooling unit at moderate and strong wind conditions. Simultaneous usage of windbreak walls and overshower deflectors may increase efficiency up to 20–30 % for the deflectors angle a = 60o. Simulation let one analyze aerodynamic patterns, induced inside cooling tower and homogeneity of velocities’ field in irrigator’s area.Presented results may be helpful for the CT aerodynamic design optimization, particularly, for perspective hybrid type CTs.

  4. Wind tunnel experimental study on effect of inland nuclear power plant cooling tower on air flow and dispersion of pollutant

    International Nuclear Information System (INIS)

    Qiao Qingdang; Yao Rentai; Guo Zhanjie; Wang Ruiying; Fan Dan; Guo Dongping; Hou Xiaofei; Wen Yunchao

    2011-01-01

    A wind tunnel experiment for the effect of the cooling tower at Taohuajiang nuclear power plant on air flow and dispersion of pollutant was introduced in paper. Measurements of air mean flow and turbulence structure in different directions of cooling tower and other buildings were made by using an X-array hot wire probe. The effects of the cooling tower and its drift on dispersion of pollutant from the stack were investigated through tracer experiments. The results show that the effect of cooling tower on flow and dispersion obviously depends on the relative position of stack to cooling towers, especially significant for the cooling tower parallel to stack along wind direction. The variation law of normalized maximum velocity deficit and perturbations in longitudinal turbulent intensity in cooling tower wake was highly in accordance with the result of isolated mountain measured by Arya and Gadiyaram. Dispersion of pollutant in near field is significantly enhanced and plume trajectory is changed due to the cooling towers and its drift. Meanwhile, the effect of cooling tower on dispersion of pollutant depends on the height of release. (authors)

  5. Calculation of Lightning Transient Responses on Wind Turbine Towers

    Directory of Open Access Journals (Sweden)

    Xiaoqing Zhang

    2013-01-01

    Full Text Available An efficient method is proposed in this paper for calculating lightning transient responses on wind turbine towers. In the proposed method, the actual tower body is simplified as a multiconductor grid in the shape of cylinder. A set of formulas are given for evaluating the circuit parameters of the branches in the multiconductor grid. On the basis of the circuit parameters, the multiconductor grid is further converted into an equivalent circuit. The circuit equation is built in frequency-domain to take into account the effect of the frequency-dependent characteristic of the resistances and inductances on lightning transients. The lightning transient responses can be obtained by using the discrete Fourier transform with exponential sampling to take the inverse transform of the frequency-domain solution of the circuit equation. A numerical example has been given for examining the applicability of the proposed method.

  6. Centrifuge and Numerical Modeling of Monopiles for Offshore Wind Towers Installed in Clay

    OpenAIRE

    Murali, Madhuri; Grajales, Francisco; Beemer, Ryan D.; Biscontin, Giovanna; Aubeny, Charles

    2015-01-01

    This is a metadata record relating to an article that cannot be shared due to publisher copyright. Offshore wind power has gained momentum as a means to diversify the world’s energy infrastructure; however, little is still known of the global stiffness behavior of the large diameter low aspect ratio monopiles which have become the foundation of choice for offshore wind towers. Traditionally, offshore foundations have been associated with gravity structures for the oil and gas industry, whi...

  7. Cooling tower calculations

    International Nuclear Information System (INIS)

    Simonkova, J.

    1988-01-01

    The problems are summed up of the dynamic calculation of cooling towers with forced and natural air draft. The quantities and relations are given characterizing the simultaneous exchange of momentum, heat and mass in evaporative water cooling by atmospheric air in the packings of cooling towers. The method of solution is clarified in the calculation of evaporation criteria and thermal characteristics of countercurrent and cross current cooling systems. The procedure is demonstrated of the calculation of cooling towers, and correction curves and the effect assessed of the operating mode at constant air number or constant outlet air volume flow on their course in ventilator cooling towers. In cooling towers with the natural air draft the flow unevenness is assessed of water and air relative to its effect on the resulting cooling efficiency of the towers. The calculation is demonstrated of thermal and resistance response curves and cooling curves of hydraulically unevenly loaded towers owing to the water flow rate parameter graded radially by 20% along the cross-section of the packing. Flow rate unevenness of air due to wind impact on the outlet air flow from the tower significantly affects the temperatures of cooled water in natural air draft cooling towers of a design with lower demands on aerodynamics, as early as at wind velocity of 2 m.s -1 as was demonstrated on a concrete example. (author). 11 figs., 10 refs

  8. Tower Mesonetwork Climatology and Interactive Display Tool

    Science.gov (United States)

    Case, Jonathan L.; Bauman, William H., III

    2004-01-01

    Forecasters at the 45th Weather Squadron and Spaceflight Meteorology Group use data from the tower network over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) to evaluate Launch Commit Criteria, and issue and verify forecasts for ground operations. Systematic biases in these parameters could adversely affect an analysis, forecast, or verification. Also, substantial geographical variations in temperature and wind speed can occur under specific wind directions. To address these concerns, the Applied Meteorology Unit (AMU) developed a climatology of temperatures and winds from the tower network, and identified the geographical variation and significant tower biases. The mesoclimate is largely driven by the complex land-water interfaces across KSC/CCAFS. Towers with close proximity to water typically had much warmer nocturnal temperatures and higher wind speeds throughout the year. The strongest nocturnal wind speeds occurred from October to March whereas the strongest mean daytime wind speeds occurred from February to May. These results of this project can be viewed by forecasters through an interactive graphical user interface developed by the AMU. The web-based interface includes graphical and map displays of mean, standard deviation, bias, and data availability for any combination of towers, variables, months, hours, and wind directions.

  9. The experimental study on the wind turbine’s guide-vanes and diffuser of an exhaust air energy recovery system integrated with the cooling tower

    International Nuclear Information System (INIS)

    Chong, W.T.; Hew, W.P.; Yip, S.Y.; Fazlizan, A.; Poh, S.C.; Tan, C.J.; Ong, H.C.

    2014-01-01

    Highlights: • On-site exhaust air energy recovery turbine generator mounted above cooling tower. • Energy from wasted wind resources is re-used for electricity generation. • Optimum angle arrangement of guide-vanes and diffusers help to improve wind-flow. • Enclosure solves conventional wind turbine problems. • 13.3% reduction in CO 2 emission is expected to be achieved from this system. - Abstract: An assembly of two vertical axis wind turbines (VAWTs) and an enclosure is installed above a cooling tower to harness the discharged wind for electricity generation. The enclosure consists of guide-vanes and diffuser-plates, is used to enhance the rotational speed of the turbines for power augmentation. The angle of the guide-vanes is optimized to ensure the oncoming wind stream impinges the rotor blades of the turbine at an optimum angle. The diffuser-plates are tilted at an optimum angle to increase the discharged airflow rate. The performance of the system is tested in the laboratory followed by a field test on an actual size cooling tower. The VAWT performance is increased in the range of 7–8% with the integration of enclosure. There is no significant difference in the current consumption of the fan motor between the bare cooling tower and the one with installed VAWTs. With the presence of this system, approximately 17.5 GW h/year is expected to be recovered from 3000 units of cooling towers at commercial areas, assuming the cooling tower is driven by a 7.5 kW fan motor and operates 16 h/day. This amount of recovered energy can also be translated into 13% reduction in CO 2 emission

  10. Stochastic Analysis of the Influence of Tower Shadow on Fatigue Life of Wind Turbine Blade

    DEFF Research Database (Denmark)

    Pedersen, Ronnie; Nielsen, Søren R.K.; Thoft-Christensen, Palle

    2012-01-01

    . The blade stresses are calculated from a dynamic mechanical model based on a two dynamic degree of freedom with quasi-static correction for higher modes. The self-induced aero-elastic loading and the turbulence loading are modeled by means of a quasi-static model linearized around the operational point......Fatigue damage accumulation in upwind turbine blades is primarily influenced by turbulence in the inflow. However, the stress reversals during blade passages through the stagnating and deflected mean wind field in front of the tower also contributes significantly. In the paper the lower order...... statistical moments of the fatigue life of a blade are estimated and compared for a turbine with a tripod tower and a standard mono-tower, respectively. The stagnation zones for each of the legs of the tripod are narrower than for the mono-tower, and hence the stress reversals will be comparable smaller...

  11. Dynamic Analysis of Wind Turbine Towers on Flexible Foundations

    Directory of Open Access Journals (Sweden)

    S. Adhikari

    2012-01-01

    Full Text Available Offshore wind turbines are considered as an essential part to develop sustainable, alternative energy sources. The structures themselves are both slender and highly flexible, with a subsea foundation typically consisting of a single large diameter monopile. They are subject to intense wind and wave loadings, with the result that significant movement of both the exposed structure and the upper part of the monopile can occur. Although the structures are intended for design life of 25 to 30 years, very little is known about the long term behaviour of these structures. This paper characterizes the dynamic behaviour of these structures. A simplified approach has been proposed for the free vibration analysis of wind turbines taking the effect of foundation into account. The method is based on an Euler-Bernoulli beam-column with elastic end supports. The elastic end-supports are considered to model the flexible nature of the interaction of these systems with the foundation. A closed-form expression of the characteristic equation governing all the natural frequencies of the system has been derived. Theoretical developments are explained by practical numerical examples. Analytical as well as a new experimental approach has been proposed to determine the parameters for the foundation. Some design issues of wind turbine towers are discussed from the point of view of the foundation parameters.

  12. Investigation of the stochastic subspace identification method for on-line wind turbine tower monitoring

    Science.gov (United States)

    Dai, Kaoshan; Wang, Ying; Lu, Wensheng; Ren, Xiaosong; Huang, Zhenhua

    2017-04-01

    Structural health monitoring (SHM) of wind turbines has been applied in the wind energy industry to obtain their real-time vibration parameters and to ensure their optimum performance. For SHM, the accuracy of its results and the efficiency of its measurement methodology and data processing algorithm are the two major concerns. Selection of proper measurement parameters could improve such accuracy and efficiency. The Stochastic Subspace Identification (SSI) is a widely used data processing algorithm for SHM. This research discussed the accuracy and efficiency of SHM using SSI method to identify vibration parameters of on-line wind turbine towers. Proper measurement parameters, such as optimum measurement duration, are recommended.

  13. Design, fabrication, and initial test of a fixture for reducing the natural frequency of the Mod-O wind turbine tower

    Science.gov (United States)

    Winemiller, J. R.; Sullivan, T. L.; Sizemore, R. L.; Yee, S. T.

    1979-01-01

    It was desired to observe the behavior of a two bladed wind turbine where the tower first bending natural frequency is less than twice the rotor speed. The system then passes through resonance when accelerating to operating speed. The frequency of the original Mod-O tower was reduced by placing it on a spring fixture. The fixture is adjustable to provide a range of tower bending frequencies. Fixture design details are given and behavior during initial operation is described.

  14. Structural inspection and wind analysis of redwood cooling towers at the Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Chung, T.; Solack, T.; Hortel, J.

    1991-01-01

    As part of the plant upgrade program, structural analyses and field inspections were performed on four redwood cooling towers at the DOE Portsmouth gaseous diffusion plant located in Piketon, Ohio. The cooling towers are categorized as important hazard facilities. The loadings are derived from UCRL-15910 according to the pertinent hazard category. In addition to the seismic and wind loadings, the wood cooling towers are constantly subject to adverse environmental effects such as elevated temperature, chemical attack, icing and snow load, and motor vibrations. A thorough structural evaluation for all load combinations was performed for each of the cooling towers based on the structural code requirements of the Cooling Tower Institute and National Forest Products Association. Most stress criteria are unique for the redwood material. This evaluation was performed using finite element techniques on the global structural integrity and supplemented by hand calculations on the individual connection joints. Overloaded wood structural members and joints are identified by the analysis. The rectangular tower structure sits on a concrete basin that span across 60 ft by 200 ft. A major part of the cooling towers upgrading program involved field inspections of the individual cells of each tower. The primary purpose of these inspections was to identify any existing structural damage or deficiencies such as failed members, degraded wood, and deficiencies resulting from poor construction practice. Inspection of 40 cells identified some generic deficiencies that mostly are consistent with the analytical finding. Based on the analysis, some effective but inexpensive upgrading techniques were developed and recommended to bring the cooling towers into compliance with current DOE requirements

  15. Wind Generation on Winnebago Tribal Lands

    Energy Technology Data Exchange (ETDEWEB)

    Multiple

    2009-09-30

    The Winnebago Wind Energy Study evaluated facility-scale, community-scale and commercial-scale wind development on Winnebago Tribal lands in northeastern Nebraska. The Winnebago Tribe of Nebraska has been pursuing wind development in various forms for nearly ten years. Wind monitoring utilizing loaned met towers from NREL took place during two different periods. From April 2001 to April 2002, a 20-meter met tower monitored wind data at the WinnaVegas Casino on the far eastern edge of the Winnebago reservation in Iowa. In late 2006, a 50-meter tower was installed, and subsequently monitored wind data at the WinnaVegas site from late 2006 through late 2008. Significant challenges with the NREL wind monitoring equipment limited the availability of valid data, but based on the available data, average wind speeds between 13.6 – 14.3 miles were indicated, reflecting a 2+/3- wind class. Based on the anticipated cost of energy produced by a WinnaVegas wind turbine, and the utility policies and rates in place at this time, a WinnaVegas wind project did not appear to make economic sense. However, if substantial grant funding were available for energy equipment at the casino site, and if either Woodbury REC backup rates were lower, or NIPCO was willing to pay more for wind power, a WinnaVegas wind project could be feasible. With funding remaining in the DOE-funded project budget,a number of other possible wind project locations on the Winnebago reservation were considered. in early 2009, a NPPD-owned met tower was installed at a site identified in the study pursuant to a verbal agreement with NPPD which provided for power from any ultimately developed project on the Western Winnebago site to be sold to NPPD. Results from the first seven months of wind monitoring at the Western Winnebago site were as expected at just over 7 meters per second at 50-meter tower height, reflecting Class 4 wind speeds, adequate for commercial development. If wind data collected in the remaining

  16. Simultaneous prediction of internal and external aerodynamic and thermal flow fields of a natural-draft cooling tower in a cross-wind

    International Nuclear Information System (INIS)

    Radosavljevic, D.; Spalding, D.B.

    1989-01-01

    The quantitative simulation of cooling-tower performance is useful to designers, enabling them to make optimal choices regarding: the type, volume and shape of the packing (i.e. fill); and the shape and size of the tower. In order to simulate performance realistically, non-uniformities of distribution of water and air mass-flow rates across the tower radius must be taken into account. This necessitates at least 2D modeling; and in order to establish the influence of a cross-wind, boundary conditions must be far away from the tower inlet and outlet, and 3D modeling must be performed. This paper is concerned with large wet natural-draught cooling towers of the type used in many steam power stations for cooling large quantities of water by direct contact with the atmosphere. The aim of the present work has been to improve the procedures of calculation by using numerical integration of the heat and mass transfer equations, and to connect internal and external aerodynamics thus enabling wind influence to be studied. It permits predicting the performance of a proposed design of the tower over a range of operating conditions. PHOENICS, a general-purpose computer code for fluid-flow simulation, is used to provide numerical solutions to governing differential equations

  17. Integrity of reinforced concrete cooling towers under extreme loads: Wind and earthquake

    International Nuclear Information System (INIS)

    Louhi, Amine

    2015-01-01

    The authorities have planned to increase the lifetime of currently operating nuclear power plants. The ageing of reinforced concrete structures such as cooling towers should be evaluated and its impact on the bearing capacity calculated. In the case of significant damage, the strengthening must be considered to ensure the sustainability of these towers facing the risk of storms and earthquakes becoming more and more frequent. This work aims to quantify the adverse effects that can generate concrete cracks and rebar section loss induced by corrosion, especially on the bearing capacity of nuclear power plant cooling towers under monotonic or cyclic extreme load conditions (wind and earthquake). These loads are certainly the most severe, since they take the structure into the nonlinear domain and can induce or amplify cracking damage. Numerical simulations are proposed to determine the quasi-static or dynamic response of the structure, taking into account appearance of concrete cracks and their evolution via an appropriate material concrete law and rebar's yielding. In the case of a seismic load, the responses are evaluated by three different methods; the nonlinear response history analysis (NLRHA), the response spectrum analysis and the modal response history analysis (MRHA) in order to compare the earthquake modeling approaches and to evaluate the robustness of the results. Parametric studies on damping, load combinations and structural configurations, are also performed. In the case of a wind load, the strengthening technique using composite materials, such as carbon fiber reinforced plastic (CFRP) is modeled. The behavior of the damaged structure with an advanced corrosion rate is estimated in the pre- and post-cracking regime, compared to the undamaged structure. The drop of bearing capacity is quantified, a reinforcement designed is proposed to restore the integrity and thus increase the lifetime of the structure. (author)

  18. Frequency analysis of a tower-cable coupled system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Moo Yeol [Young Sin Precision Engineering Ltd., Gyungju (Korea, Republic of); Kim, Seock Hyun; Park, In Su [Kangwon National University, Chuncheon (Korea, Republic of); Cui, Chengxun [Yanbian University, Yangji (China)

    2013-06-15

    This study considers the prediction of natural frequency to avoid resonance in a wind turbine tower- cable coupled system. An analytical model based on the Rayleigh-Ritz method is proposed to predict the resonance frequency of a wind turbine tower structure supported by four guy cables. To verify the validity of the analytical model, a small tower-cable model is manufactured and tested. The frequency and mode data of the tower model are obtained by modal testing and finite element analysis. The validity of the proposed method is verified through the comparison of the frequency analysis results. Finally, using a parametric study with the analytical model, we identified how the cable tension and cable angle affect the resonance frequency of the wind turbine tower structure. From the analysis results, the tension limit and optimal angle of the cable are identified.

  19. Dry cross-flow cooling tower

    Energy Technology Data Exchange (ETDEWEB)

    Fordyce, H E

    1975-01-23

    The invention deals with dry cooling towers in particular a circular cooling tower of the mechanical-draught construction whose operating characteristics should be independent of the wind direction. The recycling of the hot air should be as low as possible without necessitating high fan or natural-draught shafts, so that the costs of the tower can be brought down to a minimum.

  20. Assessment of wind turbine seismic risk : existing literature and simple study of tower moment demand.

    Energy Technology Data Exchange (ETDEWEB)

    Prowell, Ian (University of California, San Diego, CA); Veers, Paul S.

    2009-03-01

    Various sources of risk exist for all civil structures, one of which is seismic risk. As structures change in scale, the magnitude of seismic risk changes relative to risk from other sources. This paper presents an introduction to seismic hazard as applied to wind turbine structures. The existing design methods and research regarding seismic risk for wind turbines is then summarized. Finally a preliminary assessment is made based on current guidelines to understand how tower moment demand scales as rated power increases. Potential areas of uncertainty in the application of the current guidelines are summarized.

  1. Contrastive analysis of cooling performance between a high-level water collecting cooling tower and a typical cooling tower

    Science.gov (United States)

    Wang, Miao; Wang, Jin; Wang, Jiajin; Shi, Cheng

    2018-02-01

    A three-dimensional (3D) numerical model is established and validated for cooling performance optimization between a high-level water collecting natural draft wet cooling tower (HNDWCT) and a usual natural draft wet cooling tower (UNDWCT) under the actual operation condition at Wanzhou power plant, Chongqing, China. User defined functions (UDFs) of source terms are composed and loaded into the spray, fill and rain zones. Considering the conditions of impact on three kinds of corrugated fills (Double-oblique wave, Two-way wave and S wave) and four kinds of fill height (1.25 m, 1.5 m, 1.75 m and 2 m), numerical simulation of cooling performance are analysed. The results demonstrate that the S wave has the highest cooling efficiency in three fills for both towers, indicating that fill characteristics are crucial to cooling performance. Moreover, the cooling performance of the HNDWCT is far superior to that of the UNDWCT with fill height increases of 1.75 m and above, because the air mass flow rate in the fill zone of the HNDWCT improves more than that in the UNDWCT, as a result of the rain zone resistance declining sharply for the HNDWCT. In addition, the mass and heat transfer capacity of the HNDWCT is better in the tower centre zone than in the outer zone near the tower wall under a uniform fill layout. This behaviour is inverted for the UNDWCT, perhaps because the high-level collection devices play the role of flow guiding in the inner zone. Therefore, when non-uniform fill layout optimization is applied to the HNDWCT, the inner zone increases in height from 1.75 m to 2 m, the outer zone reduces in height from 1.75 m to 1.5 m, and the outlet water temperature declines approximately 0.4 K compared to that of the uniform layout.

  2. Cross-winds effect on the performance of natural draft wet cooling towers

    Energy Technology Data Exchange (ETDEWEB)

    Al-Waked, R. [Dhofar Univ., Mechanical Engineering Dept., College of Engineering, Sultanate of Oman (Oman)

    2010-01-15

    Effects of cross-winds on the thermal performance of natural draft wet cooling towers (NDWCTs) have been investigated. A three-dimensional CFD model has been used to determine the effect of cross-winds on NDWCTs performance surrounded by power plant building structures. The three-dimensional CFD model has utilized the standard k-{epsilon} turbulence model as the turbulence closure. Two cases have been investigated: a stand-alone NDWCT and two NDWCTs within a proposed power plant structures (PPS). It has been found that regardless of the cross-winds direction, an increase of 1.3 k or more could be predicted at cross-winds speeds greater than 4 m/s. Furthermore, the performance of NDWCTs under cross-winds has been found to be dependent on the three major factors: the structure of the approaching cross-winds and whether it is disturbed or undisturbed, the location of the NDWCT in the wake of the other NDWCT, and the location of the NDWCT in front of/in the wake of the PPS. When comparing results from the stand-alone and from the NDWCTs within PPS simulations, differences in {delta}T{sub wo} were found to be less than 1 K for the whole span of cross-winds speeds and could be decreased to 0.7 K for speeds less than 8 m/s. Finally, results obtained from the simulation of a stand-alone NDWCT could be used instead of those from NDWCTs within PPS at a certain cross-winds direction for qualitative comparisons. (authors)

  3. Cross-winds effect on the performance of natural draft wet cooling towers

    International Nuclear Information System (INIS)

    Al-Waked, R.

    2010-01-01

    Effects of cross-winds on the thermal performance of natural draft wet cooling towers (NDWCTs) have been investigated. A three-dimensional CFD model has been used to determine the effect of cross-winds on NDWCTs performance surrounded by power plant building structures. The three-dimensional CFD model has utilized the standard k-ε turbulence model as the turbulence closure. Two cases have been investigated: a stand-alone NDWCT and two NDWCTs within a proposed power plant structures (PPS). It has been found that regardless of the cross-winds direction, an increase of 1.3 k or more could be predicted at cross-winds speeds greater than 4 m/s. Furthermore, the performance of NDWCTs under cross-winds has been found to be dependent on the three major factors: the structure of the approaching cross-winds and whether it is disturbed or undisturbed, the location of the NDWCT in the wake of the other NDWCT, and the location of the NDWCT in front of/in the wake of the PPS. When comparing results from the stand-alone and from the NDWCTs within PPS simulations, differences in ΔT wo were found to be less than 1 K for the whole span of cross-winds speeds and could be decreased to 0.7 K for speeds less than 8 m/s. Finally, results obtained from the simulation of a stand-alone NDWCT could be used instead of those from NDWCTs within PPS at a certain cross-winds direction for qualitative comparisons. (authors)

  4. Effect of Tower Shadow and Wind Shear in a Wind Farm on AC Tie-Line Power Oscillations of Interconnected Power Systems

    DEFF Research Database (Denmark)

    Tan, Jin; Hu, Weihao; Wang, Xiaoru

    2013-01-01

    This paper describes a frequency domain approach for evaluating the impact of tower shadow and wind shear effects (TSWS) on tie-line power oscillations. A simplified frequency domain model of an interconnected power system with a wind farm is developed. The transfer function, which relates the tie......-line power variation to the mechanical power variation of a wind turbine, and the expression of the maximum magnitude of tie-line power oscillations are derived to identify the resonant condition and evaluate the potential risk. The effects of the parameters on the resonant magnitude of the tie-line power...... are also discussed. The frequency domain analysis reveals that TSWS can excite large tie-line power oscillations if the frequency of TSWS approaches the tie-line resonant frequency, especially in the case that the wind farm is integrated into a relatively small grid and the tie-line of the interconnected...

  5. Numerical simulation of flow field in cooling tower of passive residual heat removal system of HTGR

    International Nuclear Information System (INIS)

    Li Xiaowei; Zhang Li; Wu Xinxin; He Shuyan

    2011-01-01

    Environmental wind will influence the working conditions of natural convection cooling tower. The velocity and temperature fields in the natural convection cooling tower of the HTGR residual heat removal system at different environmental wind velocities were numerically simulated. The results show that, if there is no wind baffle, the flow in the cooling tower is blocked when environmental wind velocity is higher than 6 m/s, residual heat can hardly be removed, and when wind velocity is higher than 9 m/s, the air even flow downwards in the tower, so wind baffle is very necessary. With the wind baffle installed, the cooling tower works well at the wind speed even higher than 9 m/s. The optimum baffle size and positions are also analyzed. (authors)

  6. Validation of the Dynamic Wake Meander model with focus on tower loads

    Science.gov (United States)

    Larsen, T. J.; Larsen, G. C.; Pedersen, M. M.; Enevoldsen, K.; Madsen, H. A.

    2017-05-01

    This paper presents a comparison between measured and simulated tower loads for the Danish offshore wind farm Nysted 2. Previously, only limited full scale experimental data containing tower load measurements have been published, and in many cases the measurements include only a limited range of wind speeds. In general, tower loads in wake conditions are very challenging to predict correctly in simulations. The Nysted project offers an improved insight to this field as six wind turbines located in the Nysted II wind farm have been instrumented to measure tower top and tower bottom moments. All recorded structural data have been organized in a database, which in addition contains relevant wind turbine SCADA data as well as relevant meteorological data - e.g. wind speed and wind direction - from an offshore mast located in the immediate vicinity of the wind farm. The database contains data from a period extending over a time span of more than 3 years. Based on the recorded data basic mechanisms driving the increased loading experienced by wind turbines operating in offshore wind farm conditions have been identified, characterized and modeled. The modeling is based on the Dynamic Wake Meandering (DWM) approach in combination with the state-of-the-art aeroelastic model HAWC2, and has previously as well as in this study shown good agreement with the measurements. The conclusions from the study have several parts. In general the tower bending and yaw loads show a good agreement between measurements and simulations. However, there are situations that are still difficult to match. One is tower loads of single-wake operation near rated ambient wind speed for single wake situations for spacing’s around 7-8D. A specific target of the study was to investigate whether the largest tower fatigue loads are associated with a certain downstream distance. This has been identified in both simulations and measurements, though a rather flat optimum is seen in the measurements.

  7. Dynamic interaction effects in cooling tower groups

    International Nuclear Information System (INIS)

    Riera, J.D.

    1984-01-01

    A theoretical and experimental determination of the dynamic response of reinforced concrete cooling towers, taking into consideration group effects, are described. The results for an individual tower are thoroughly examined. A complete analysis is then performed for the critical wind orientations, for each tower in a six towers group. It's shown that ignoring group effects in the analysis may lead to a significant underestimation of the structural response. (E.G.) [pt

  8. 77 FR 75984 - Utility Scale Wind Towers From the Socialist Republic of Vietnam: Final Determination of Sales at...

    Science.gov (United States)

    2012-12-26

    ... Determination 1. Steel Plate 2. Surrogate Financial Statements 3. Financial Ratio Adjustments 4. Packed Weight... financial statements for Ganges International Pvt Ltd. for purposes of calculating the surrogate financial ratios. Scope of the Investigation The merchandise covered by this investigation are certain wind towers...

  9. Dynamic behavior and identification of failure modes of cooling towers

    International Nuclear Information System (INIS)

    Serhan, S.J.

    1994-01-01

    The major thrust of this paper is to provide an engineering assessment of two hyperboloidal 540-foot high reinforced concrete cooling towers at a nuclear power plant relative to the proposed construction of a new safety-related facility in the shadow of these cooling towers. A three-dimensional full 360-degree finite-element model that is capable of realistically representing the response of the two cooling towers subjected to the plant design-basis safe shutdown earthquake, 90 mph wind, and 300 mph tornado is used to create a data pool which supports the proposed construction of the new facility. Dynamic time history analyses are performed to represent the complex interplay of the dynamic characteristics of the cooling towers and the input wind-pressure excitation in terms of gust factors. This study resulted in the confirmation and enhancement of many of the important aspects in the design/analysis methodologies for cooling towers reported in literature. In summary, this study provides a high confidence that no significant damage will be caused to the two cooling towers when subjected to the plant design-basis safe shutdown earthquake and the 90 mph basic wind velocity. However, the two cooling towers are expected to collapse if subjected in a direct hit to a 300 mph tornado. The nonlinear finite element analyses including base uplift performed for this study and the literature research on past failures of cooling towers due to severe wind storms confirm that the mode of failure will not be the overturning cantilever tree-type and the towers will collapse inwardly with the exception of few isolated debris

  10. 77 FR 3440 - Utility Scale Wind Towers From the People's Republic of China and the Socialist Republic of...

    Science.gov (United States)

    2012-01-24

    ... comments that they feel are relevant to the development of an accurate listing of physical characteristics... the main Department of Commerce building. In determining whether Petitioner has standing under section... price (``EP'') based on declarations of the price bid for wind towers by a certain Chinese exporter...

  11. Floating wind turbine system

    Science.gov (United States)

    Viterna, Larry A. (Inventor)

    2009-01-01

    A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

  12. Cooling tower drift: comprehensive case study

    International Nuclear Information System (INIS)

    Laulainen, N.S.; Ulanski, S.L.

    1979-01-01

    A comprehensive experiment to study drift from mechanical drift cooling towers was conducted during June 1978 at the PG and E Pittsburg Power Plant. The data from this study will be used for validation of drift deposition models. Preliminary results show the effects of tower geometry and orientation with respect to the wind and to single- or two-tower operation. The effect of decreasing relative humidity during a test run can also be seen

  13. Optimal Tuning of Multivariable Disturbance-Observer-Based Control for Flicker Mitigation Using Individual Pitch Control of Wind Turbine

    DEFF Research Database (Denmark)

    Raja, Muhammad Imran; Hussain, Dil muhammed Akbar; Soltani, Mohsen

    2017-01-01

    Multivariable disturbance accommodated observer based control (DOBC) scheme is presented to mitigate loads generated due to wind shear and tower shadow using individual blade pitch for above-rated wind speed condition of wind turbine. Wind shear and tower shadow add flickers as 1p, 3p, 6p and so on......, (p is the rotor rotational frequency) for three-bladed wind turbine. Novel DOBC with individual pitch control (IPC) to mitigate the flickers is presented and linear state-space model of wind turbine with tower dynamics is developed. The proposed controller is tuned using optimal control theory...... density of generator speed, drive-train torsion and tower fore-aft moment shows better mitigation to the flickers by proposed controller as compared with proportional–integral (PI) and disturbance accommodation control (DAC) with collective pitch control. Furthermore, it shows less degradation...

  14. Wind-induced Vibrations in the European Court Towers

    DEFF Research Database (Denmark)

    Hansen, Jannick B.; Brincker, Rune; Andersen, Ken G.

    2012-01-01

    Issues regarding occupancy comfort in vibration-sensitive structures are the motivation of this study concerning windinduced vibrations in the European Court Towers in Luxembourg. In one of the two identical towers tuned liquid dampers (TLD) have been installed. Recent studies investigate the cha...

  15. A Meso-Climatology Study of the High-Resolution Tower Network Over the Florida Spaceport

    Science.gov (United States)

    Case, Jonathan L.; Bauman, William H., III

    2004-01-01

    Forecasters at the US Air Force 45th Weather Squadron (45 WS) use wind and temperature data from the tower network over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) to evaluate Launch Commit Criteria and to issue and verify temperature and wind advisories, watches, and warnings for ground operations. The Spaceflight Meteorology Group at the Johnson Space Center in Houston, TX also uses these data when issuing forecasts for shuttle landings at the KSC Shuttle Landing Facility. Systematic biases in these parameters at any of the towers could adversely affect an analysis, forecast, or verification for all of these operations. In addition, substantial geographical variations in temperature and wind speed can occur under specific wind directions. Therefore, the Applied Meteorology Unit (AMU), operated by ENSCO Inc., was tasked to develop a monthly and hourly climatology of temperatures and winds from the tower network, and identify the geographical variation, tower biases, and the magnitude of those biases. This paper presents a sub-set of results from a nine-year climatology of the KSC/CCAFS tower network, highlighting the geographical variations based on location, month, times of day, and specific wind direction regime. Section 2 provides a description of the tower mesonetwork and instrumentation characteristics. Section 3 presents the methodology used to construct the tower climatology including QC methods and data processing. The results of the tower climatology are presented in Section 4 and Section 5 summarizes the paper.

  16. Dissipation of Turbulence in the Wake of a Wind Turbine

    Science.gov (United States)

    Lundquist, J. K.; Bariteau, L.

    2015-02-01

    The wake of a wind turbine is characterized by increased turbulence and decreased wind speed. Turbines are generally deployed in large groups in wind farms, and so the behaviour of an individual wake as it merges with other wakes and propagates downwind is critical in assessing wind-farm power production. This evolution depends on the rate of turbulence dissipation in the wind-turbine wake, which has not been previously quantified in field-scale measurements. In situ measurements of winds and turbulence dissipation from the wake region of a multi-MW turbine were collected using a tethered lifting system (TLS) carrying a payload of high-rate turbulence probes. Ambient flow measurements were provided from sonic anemometers on a meteorological tower located near the turbine. Good agreement between the tower measurements and the TLS measurements was established for a case without a wind-turbine wake. When an operating wind turbine is located between the tower and the TLS so that the wake propagates to the TLS, the TLS measures dissipation rates one to two orders of magnitude higher in the wake than outside of the wake. These data, collected between two and three rotor diameters downwind of the turbine, document the significant enhancement of turbulent kinetic energy dissipation rate within the wind-turbine wake. These wake measurements suggest that it may be useful to pursue modelling approaches that account for enhanced dissipation. Comparisons of wake and non-wake dissipation rates to mean wind speed, wind-speed variance, and turbulence intensity are presented to facilitate the inclusion of these measurements in wake modelling schemes.

  17. Performance Evaluation of the Multi-stage Tower-type Vertical-axis Wind Turbine%多层塔式H型立轴风机的性能分析

    Institute of Scientific and Technical Information of China (English)

    高振勋; 蒋崇文; 唐金龙; 王德宝

    2011-01-01

    The main ideal of the multi-stage tower type vertical-axis wind turbine is to utilize the superposition of multi group H-type vertical-axis wind turbines to generate power, and fully use the wind energy in different altitude, which is beneficial for the large-scale development of modern wind turbine. The performance compari sons between the multi-stage tower-type vertical-axis wind turbine and traditional wind turbine were performed on many aspects. It was pointed out that the multi-stage tower-type vertical-axis wind turbine can have many advantages, such as easy-machining blades, high power efficiency, avoidance of the yawing system, reasonable structure loading, and low manufacture/maintenance cost. However, some disadvantages exist, such as the aerodynamic drag brought in by the blade supporting structure, complicated tower construction, and incremental requirement for gearbox and shaft joint. Overall considering, the multi stage tower-type vertical-axis wind turbine has extensive prospect of market applications.%多层塔式立轴风机的核心思想是将多组H型立轴风机分层叠加组合发电,结构简单性能优异,非常适合大容量的风电机组,符合现代风机向大型化发展的方向。对多层塔式立轴风机与传统风机的多方面性能进行了对比,指出多层塔式立轴风机具有风能利用率高、叶片制造简单、无需偏航系统、结构载荷合理、制造维护成本低等诸多优点,但也存在一些缺点,如叶片支撑结构会引入气动阻力、塔架设计较复杂、需要多组齿轮箱及联轴器等。总体分析表明,多层塔式立轴风机的方案在技术上和经济上是可行的。

  18. Bird strike and electrocutions at power lines, communication towers, and wind turbines: state of the art and state of the science - next steps toward mitigation

    Science.gov (United States)

    Albert M. Manville II

    2005-01-01

    Migratory birds suffer considerable human-caused mortality from structures built to provide public services and amenities. Three such entities are increasing nationwide: communication towers, power lines, and wind turbines. Communication towers have been growing at an exponential rate over at least the past 6 years. The U.S. Fish and Wildlife Service is especially...

  19. The Schmehausen cable net cooling tower

    International Nuclear Information System (INIS)

    Schlaich, J.; Mayr, G.; Weber, P.; Jasch, E.

    1976-01-01

    The prototype of a large cable net shell as a natural-draught cooling tower for the THTR-300 is presented. Results of wind tunnel tests and calculations are given, and the capacity is discussed. Design features of the main components are presented in illustrations and are described with regard to the construction process of the cooling tower. Finally, it is shown that the cable net cooling tower is a suitable construction for large dimensions and caving-in or seismic areas. (orig./HP) [de

  20. A Study of Nonstationary Wind Effects on a Full-Scale Large Cooling Tower Using Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    X. X. Cheng

    2017-01-01

    Full Text Available Wind effects on structures obtained by field measurements are often found to be nonstationary, but related researches shared by the wind-engineering community are still limited. In this paper, empirical mode decomposition (EMD is applied to the nonstationary wind pressure time-history samples measured on an actual 167-meter high large cooling tower. It is found that the residue and some intrinsic mode functions (IMFs of low frequencies produced by EMD are responsible for the samples’ nonstationarity. Replacing the residue by the constant mean and subtracting the IMFs of low frequencies can help the nonstationary samples become stationary ones. A further step is taken to compare the loading characteristics extracted from the original nonstationary samples with those extracted from the processed stationary samples. Results indicate that nonstationarity effects on wind loads are notable in most cases. The passive wind tunnel simulation technique based on the assumption of stationarity is also examined, and it is found that the technique is basically conservative for use.

  1. Structure of natural draft cooling towers, 1. Study on cooling tower shells

    Energy Technology Data Exchange (ETDEWEB)

    Ishioka, H; Sakamoto, Y; Tsurusaki, M; Koshizawa, K; Chiba, T [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1976-09-01

    Recently in Japan, demands for cooling tower systems have been increasing remarkably with the construction of large power plants and the legislation of environmental regulations. In view of the severe natural conditions in Japan such as strong wind and seismic loadings, etc., the establishment of the optimum design and construction method is essential for the building of safe and economical towers. In order to establish a comprehensive plan of a power plant cooling system of the appropriate structural type, the authors have made researches and experiments on design conditions, static and dynamic analyses, and comparative studies of various structural types such as reinforced concrete thin-shell structures, steel framed structures and composite shell segment structures, based on the investigation results of towers in Europe and America. These results are presented in three reports, the 1st of which concerns cooling tower shells as are herein described.

  2. Coastal Ohio Wind Project

    Energy Technology Data Exchange (ETDEWEB)

    Gorsevski, Peter [Bowling Green State Univ., OH (United States); Afjeh, Abdollah [Univ. of Toledo, OH (United States); Jamali, Mohsin [Univ. of Toledo, OH (United States); Bingman, Verner [Bowling Green State Univ., OH (United States)

    2014-04-04

    using different evaluation criteria, and an Android application for collection of field data using mobile and tablet devices . In summary, the simulations of two- and three-blade wind turbines suggested that two-bladed machines could produce comparable annual energy as the three-blade wind turbines but have a lighter tower top weight, which leads to lower cost of energy. In addition, the two-blade rotor configuration potentially costs 20% less than a three blade configuration that produces the same power at the same site. The cost model analysis predicted a potential cost savings of approximately 15% for offshore two-blade wind turbines. The foundation design for a wind turbine in Lake Erie is likely to be driven by ice loads based on the currently available ice data and ice mechanics models. Hence, for Lake Eire, the cost savings will be somewhat smaller than the other lakes in the Great Lakes. Considering the size of cranes and vessels currently available in the Great Lakes, the cost optimal wind turbine size should be 3 MW, not larger. The surveillance data from different monitoring systems suggested that bird and bat passage rates per hour were comparable during heavy migrations in both spring and fall seasons while passage rates were significantly correlated to wind directions and wind speeds. The altitude of migration was higher during heavy migrations and higher over water relative to over land. Notable portions of migration on some spring nights occurred parallel the shoreline, often moving perpendicular to southern winds. The birds approaching the Western basin have a higher propensity to cross than birds approaching the Central basin of Lake Erie and as such offshore turbine development might be a better option further east towards Cleveland than in the Western basin. The high stopover density was more strongly associated with migration volume the following night rather than the preceding night. The processed mean scalar wind speeds with temporal resolutions

  3. Incorporating Structural Health Monitoring in the design of slip formed concrete wind turbine towers

    DEFF Research Database (Denmark)

    Hovgaard, Mads Knude

    , where the development of riskbased inspection for offshore structures has been economically motivated, the economic value added by SHM has been somewhat neglected. With a starting point in the business case of wind turbine towers made of concrete, this thesis sets up the framework for the assessing...... is different which require a different approach. As exact solution is intractable, various approximations using surrogate objective functions from detection theory, filters, decision rules and Limited Memory Influence Diagrams (LIMID) are investigated. The main focus is on damage detection but the value...

  4. Parameterized Disturbance Observer Based Controller to Reduce Cyclic Loads of Wind Turbine

    Directory of Open Access Journals (Sweden)

    Raja M. Imran

    2018-05-01

    Full Text Available This paper is concerned with bump-less transfer of parameterized disturbance observer based controller with individual pitch control strategy to reduce cyclic loads of wind turbine in full load operation. Cyclic loads are generated due to wind shear and tower shadow effects. Multivariable disturbance observer based linear controllers are designed with objective to reduce output power fluctuation, tower oscillation and drive-train torsion using optimal control theory. Linear parameterized controllers are designed by using a smooth scheduling mechanism between the controllers. The proposed parameterized controller with individual pitch was tested on nonlinear Fatigue, Aerodynamics, Structures, and Turbulence (FAST code model of National Renewable Energy Laboratory (NREL’s 5 MW wind turbine. The closed-loop system performance was assessed by comparing the simulation results of proposed controller with a fixed gain and parameterized controller with collective pitch for full load operation of wind turbine. Simulations are performed with step wind to see the behavior of the system with wind shear and tower shadow effects. Then, turbulent wind is applied to see the smooth transition of the controllers. It can be concluded from the results that the proposed parameterized control shows smooth transition from one controller to another controller. Moreover, 3p and 6p harmonics are well mitigated as compared to fixed gain DOBC and parameterized DOBC with collective pitch.

  5. Implementation of internal model based control and individual pitch control to reduce fatigue loads and tower vibrations in wind turbines

    Science.gov (United States)

    Mohammadi, Ebrahim; Fadaeinedjad, Roohollah; Moschopoulos, Gerry

    2018-05-01

    Vibration control and fatigue loads reduction are important issues in large-scale wind turbines. Identifying the vibration frequencies and tuning dampers and controllers at these frequencies are major concerns in many control methods. In this paper, an internal model control (IMC) method with an adaptive algorithm is implemented to first identify the vibration frequency of the wind turbine tower and then to cancel the vibration signal. Standard individual pitch control (IPC) is also implemented to compare the performance of the controllers in term of fatigue loads reduction. Finally, the performance of the system when both controllers are implemented together is evaluated. Simulation results demonstrate that using only IMC or IPC alone has advantages and can reduce fatigue loads on specific components. IMC can identify and suppress tower vibrations in both fore-aft and side-to-side directions, whereas, IPC can reduce fatigue loads on blades, shaft and yaw bearings. When both IMC and IPC are implemented together, the advantages of both controllers can be used. The aforementioned analysis and comparisons were not studied in literature and this study fills this gap. FAST, AreoDyn and Simulink are used to simulate the mechanical, aerodynamic and electrical aspects of wind turbine.

  6. Active tower damping and pitch balancing - design, simulation and field test

    Science.gov (United States)

    Duckwitz, Daniel; Shan, Martin

    2014-12-01

    The tower is one of the major components in wind turbines with a contribution to the cost of energy of 8 to 12% [1]. In this overview the load situation of the tower will be described in terms of sources of loads, load components and fatigue contribution. Then two load reduction control schemes are described along with simulation and field test results. Pitch Balancing is described as a method to reduce aerodynamic asymmetry and the resulting fatigue loads. Active Tower Damping is reducing the tower oscillations by applying appropiate pitch angle changes. A field test was conducted on an Areva M5000 wind turbine.

  7. Effect of rotor configuration on guyed tower and foundation designs and estimated costs for intermediate site horizontal axis wind turbines

    Science.gov (United States)

    Frederick, G. R.; Winemiller, J. R.; Savino, J. M.

    1982-01-01

    Three designs of a guyed cylindrical tower and its foundation for an intermediate size horizontal axis wind turbine generator are discussed. The primary difference in the three designs is the configuration of the rotor. Two configurations are two-blade rotors with teetering hubs - one with full span pitchable blades, the other with fixed pitch blades. The third configuration is a three-bladed rotor with a rigid hub and fixed pitch blades. In all configurations the diameter of the rotor is 38 meters and the axis of rotation is 30.4 meters above grade, and the power output is 200 kW and 400 kW. For each configuration the design is based upon for the most severe loading condition either operating wind or hurricane conditions. The diameter of the tower is selected to be 1.5 meters (since it was determined that this would provide sufficient space for access ladders within the tower) with guy rods attached at 10.7 meters above grade. Completing a design requires selecting the required thicknesses of the various cylindrical segments, the number and diameter of the guy rods, the number and size of soil anchors, and the size of the central foundation. The lower natural frequencies of vibration are determined for each design to ensure that operation near resonance does not occur. Finally, a cost estimate is prepared for each design. A preliminary design and cost estimate of a cantilever tower (cylindrical and not guyed) and its foundation is also presented for each of the three configurations.

  8. Parametric modeling and analysis of wind turbine tower based on VB and ANSYS%基于VB和ANSYS的风机塔筒参数化建模与分析

    Institute of Scientific and Technical Information of China (English)

    张彦立; 王广庆; 李曼

    2012-01-01

    为了高效、快速地建立风机塔筒的有限元模型并对其进行有限元分析,对系列机型塔筒模型的结构进行了全面的研究,采用ANSYS提供的APDL语言和命令流编程的方法,开发了一种风机塔筒的有限元参数化建模、分析及后处理程序,用可视化界面语言VB对其进行了封装.以塔筒模型分析为实例,跟传统方法作对比,对该程序进行了验证.研究结果表明,该程序能够提高有限元模型的建模效率,缩短了塔筒的设计周期,并且简单实用,为类似问题的解决提供了一条新途径.%In order to improve the efficiency of established wind turbine tower finite element model and its finite element analysis,the parametric programming language and APDL.in ANSYS were investigated.After a comprehensive study for the structure of series tower,the wind turbine program of parametric modeling,analysis and post processing was established.Visual interface VB language was presented to packaging this program. The wind turbine program was evaluated on the tower model analysis,the program was tested.The experimental results show that the program has improved the efficiency to establish finite element model of wind turbine tower and shorten the design cycle of wind turbine tower.lt is simple, practical, and provides a new way to solve the similar issues.

  9. An Assessment of Wind Plant Complex Flows Using Advanced Doppler Radar Measurements

    Science.gov (United States)

    Gunter, W. S.; Schroeder, J.; Hirth, B.; Duncan, J.; Guynes, J.

    2015-12-01

    As installed wind energy capacity continues to steadily increase, the need for comprehensive measurements of wind plant complex flows to further reduce the cost of wind energy has been well advertised by the industry as a whole. Such measurements serve diverse perspectives including resource assessment, turbine inflow and power curve validation, wake and wind plant layout model verification, operations and maintenance, and the development of future advanced wind plant control schemes. While various measurement devices have been matured for wind energy applications (e.g. meteorological towers, LIDAR, SODAR), this presentation will focus on the use of advanced Doppler radar systems to observe the complex wind flows within and surrounding wind plants. Advanced Doppler radars can provide the combined advantage of a large analysis footprint (tens of square kilometers) with rapid data analysis updates (a few seconds to one minute) using both single- and dual-Doppler data collection methods. This presentation demonstrates the utility of measurements collected by the Texas Tech University Ka-band (TTUKa) radars to identify complex wind flows occurring within and nearby operational wind plants, and provide reliable forecasts of wind speeds and directions at given locations (i.e. turbine or instrumented tower sites) 45+ seconds in advance. Radar-derived wind maps reveal commonly observed features such as turbine wakes and turbine-to-turbine interaction, high momentum wind speed channels between turbine wakes, turbine array edge effects, transient boundary layer flow structures (such as wind streaks, frontal boundaries, etc.), and the impact of local terrain. Operational turbine or instrumented tower data are merged with the radar analysis to link the observed complex flow features to turbine and wind plant performance.

  10. Numerical assessment of wind turbine blade damage due to contact/impact with tower during installation

    Science.gov (United States)

    Shankar Verma, Amrit; Petter Vedvik, Nils; Gao, Zhen

    2017-12-01

    The use of floating crane vessel for installation of offshore wind turbine blades presents a great challenge in terms of its random motions and is likely to increase the probability of the blade hitting the preassembled tower during lifting operation. To evaluate the consequences of such scenarios and to determine the allowable motions or sea states for such operations, it is very important to understand the damage development in the blade due to impact. The present paper employs the application of high fidelity finite element method to investigate the damage behavior in the blade when the leading edge of the blade hits the tower. A nonlinear time domain structural analysis using ABAQUS was conducted on the DTU 10 MW reference blade model which is based on shell elements. Damage assessment along with the nature of evolution of various energies is examined and presented for two different impact velocities with modified layup stacking sequence at the contact region.

  11. Plant Vogtle cooling tower studies

    International Nuclear Information System (INIS)

    O'Steen, L.

    2000-01-01

    Intensive ground-based field studies of plumes from two large, natural-draft cooling towers were conducted in support of the MTI modeling effort. Panchromatic imagery, IR imagery, meteorological data, internal tower temperatures and plant power data were collected during the field studies. These data were used to evaluate plume simulations, plume radioactive transfer calculations and plume volume estimation algorithms used for power estimation. Results from six field studies indicate that a 3-D atmospheric model at sufficient spatial resolution can effectively simulate a cooling tower plume if the plume is of sufficient size and the ambient meteorology is known and steady. Small plumes and gusty wind conditions degrade the agreement between the simulated and observed plumes. Thermal radiance calculations based on the simulated plumes produced maximum IR temperatures (near tower exit) which were in good agreement with measured IR temperatures for the larger plumes. For the smaller plumes, the calculated IR temperature was lower than the measured temperature by several degrees. Variations in maximum IR plume temperature with decreasing power (one reactor was undergoing a shutdown process), were clearly observed in the IR imagery and seen in the simulations. These temperature changes agreed with those calculated from an overall tower energy and momentum balance. Plume volume estimates based on camcorder images at three look angles were typically 20--30 percent larger than the plume volumes derived from the simulations, although one estimate was twice the simulated volume. Volume overestimation is expected and will have to be accounted for to some degree if plume volume is to be a useful diagnostic quantity in power estimation. Volume estimation with MTI imagery will require a large, stable plume and two looks in the visible bands (5m GSD) along with a solar shadow

  12. Active tower damping and pitch balancing – design, simulation and field test

    International Nuclear Information System (INIS)

    Duckwitz, Daniel; Shan, Martin

    2014-01-01

    The tower is one of the major components in wind turbines with a contribution to the cost of energy of 8 to 12% [1]. In this overview the load situation of the tower will be described in terms of sources of loads, load components and fatigue contribution. Then two load reduction control schemes are described along with simulation and field test results. Pitch Balancing is described as a method to reduce aerodynamic asymmetry and the resulting fatigue loads. Active Tower Damping is reducing the tower oscillations by applying appropiate pitch angle changes. A field test was conducted on an Areva M5000 wind turbine

  13. Simultaneous effects of water spray and crosswind on performance of natural draft dry cooling tower

    Directory of Open Access Journals (Sweden)

    Ahmadikia Hossein

    2013-01-01

    Full Text Available To investigate the effect of water spray and crosswind on the effectiveness of the natural draft dry cooling tower (NDDCT, a three-dimensional model has been developed. Efficiency of NDDCT is improved by water spray system at the cooling tower entrance for high ambient temperature condition with and without crosswind. The natural and forced heat convection flow inside and around the NDDCT is simulated numerically by solving the full Navier-Stokes equations in both air and water droplet phases. Comparison of the numerical results with one-dimensional analytical model and the experimental data illustrates a well-predicted heat transfer rate in the cooling tower. Applying water spray system on the cooling tower radiators enhances the cooling tower efficiency at both no wind and windy conditions. For all values of water spraying rate, NDDCTs operate most effectively at the crosswind velocity of 3m/s and as the wind speed continues to rise to more than 3 m/s up to 12 m/s, the tower efficiency will decrease by approximately 18%, based on no-wind condition. The heat transfer rate of radiator at wind velocity 10 m/s is 11.5% lower than that of the no wind condition. This value is 7.5% for water spray rate of 50kg/s.

  14. Dynamic analysis of cooling towers

    International Nuclear Information System (INIS)

    Bittnar, Z.

    1987-01-01

    Natural draught cooling towers are shell structures subjected to random vibrations due to wind turbulence and earthquake. The need of big power plant units has initiated the design of very large cooling towers. The random response of such structures may be analysed using a spectral approach and assuming a linear behaviour of the structure. As the modal superposition method is the most suitable procedure for this purpose it is necessary to determine the natural frequencies and mode shapes with adequate accuracy. (orig./GL)

  15. Towards safe and economic seismic design of cooling towers of extreme height

    International Nuclear Information System (INIS)

    Kraetzig, W.B.; Meskouris, K.

    1979-01-01

    Nuclear power plants are being increasingly equipped with natural draught cooling towers of heights greater than 160 m. In many arid zones, where high natural draught cooling towers with dry cooling systems are being projected, wind loads are relativelly small while site seismicity is relatively high. Thus the ability of the tower to withstand earthquake induced forces governs its design. On the other hand, most reinforced concrete cooling towers of extreme height built so far were designed to withstand high wind loads and moderate earthquake loads. The effects of special structural measures for obtaining an economic design, such as the introduction of ring stiffened shells, have been studied mainly for those towers. In view of the previous aspects it is the purpose of this paper to analyze the effects of various structural measures and other parameters on the seismic response of such high cooling towers. (orig.)

  16. Evaluation of Tower Shadowing on Anemometer Measurements at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, David Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-14

    The objective of this study is to evaluate the effect of tower shadowing from the meteorology towers at LANL during 2014. This study is in response to the Department of Energy Meteorological Coordinating Council visit in 2015 that recommended an evaluation of any biases in the wind data introduced by the tower and boom alignment at all meteorology towers.

  17. Fire analog: a comparison between fire plumes and energy center cooling tower plumes

    Energy Technology Data Exchange (ETDEWEB)

    Orgill, M.M.

    1977-10-01

    Thermal plumes or convection columns associated with large fires are compared to thermal plumes from cooling towers and proposed energy centers to evaluate the fire analog concept. Energy release rates of mass fires are generally larger than for single or small groups of cooling towers but are comparable to proposed large energy centers. However, significant physical differences exist between cooling tower plumes and fire plumes. Cooling tower plumes are generally dominated by ambient wind, stability and turbulence conditions. Fire plumes, depending on burning rates and other factors, can transform into convective columns which may cause the fire behavior to become more violent. This transformation can cause strong inflow winds and updrafts, turbulence and concentrated vortices. Intense convective columns may interact with ambient winds to create significant downwind effects such as wakes and Karman vortex streets. These characteristics have not been observed with cooling tower plumes to date. The differences in physical characteristics between cooling tower and fire plumes makes the fire analog concept very questionable even though the approximate energy requirements appear to be satisfied in case of large energy centers. Additional research is suggested in studying the upper-level plume characteristics of small experimental fires so this information can be correlated with similar data from cooling towers. Numerical simulation of fires and proposed multiple cooling tower systems could also provide comparative data.

  18. U.S. Virgin Islands Wind Resources Update 2014

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, J. O.; Warren, A.

    2014-12-01

    This report summarizes the data collected from two 60-meter meteorological towers and three sonic detection and ranging units on St. Thomas and St. Croix in 2012 and 2013. These results are an update to the previous feasibility study; the collected data are critical to the successful development of a wind project at either site.

  19. Analysis of Differential Quadrature Method on Wind Turbine Tower Free Vibration%风电机组塔架自由振动的微分求积法分析

    Institute of Scientific and Technical Information of China (English)

    王清波; 陈婷

    2013-01-01

    塔架结构的振动,不仅会引起塔架的附加应力,影响其结构强度,而且还会影响风轮的变形和振动,从而影响其性能。因此,在风电机组的设计中,必须分析计算风力引起的塔架结构动力学问题。本文介绍了微分求积法原理,使用该方法求解了风电机组锥筒型塔架的固有频率,并与其它数值方法求解的结果进行了对比,结果表明,微分求积法原理简单,计算量小,精度较高,且易于在计算机上实现。%Te vibration of wind turbine tower structure can not only cause the additional stress of the tower, afect the structural strength, but also afect the deformation and vibration of the wind turbine rotor, which afects its performance. Terefore, the analysis and calculation of the wind turbine tower structure dynamics caused by the wind shall be taken into account in the design of the wind turbine. Te principle of the diferential quadrature method has been introduced in this paper. Te natural frequency of the taper cylinder tower has been computed by this method. Numerical results from this approach are compared with other numerical methods. It is shown that the principle of differential quadrature method is simple, and its computation efficiency is higher, accuracy, and easy to implement on computer.

  20. Increasing evidence that bats actively forage at wind turbines.

    Science.gov (United States)

    Foo, Cecily F; Bennett, Victoria J; Hale, Amanda M; Korstian, Jennifer M; Schildt, Alison J; Williams, Dean A

    2017-01-01

    Although the ultimate causes of high bat fatalities at wind farms are not well understood, several lines of evidence suggest that bats are attracted to wind turbines. One hypothesis is that bats would be attracted to turbines as a foraging resource if the insects that bats prey upon are commonly present on and around the turbine towers. To investigate the role that foraging activity may play in bat fatalities, we conducted a series of surveys at a wind farm in the southern Great Plains of the US from 2011-2016. From acoustic monitoring we recorded foraging activity, including feeding buzzes indicative of prey capture, in the immediate vicinity of turbine towers from all six bat species known to be present at this site. From insect surveys we found Lepidoptera, Coleoptera, and Orthoptera in consistently high proportions over several years suggesting that food resources for bats were consistently available at wind turbines. We used DNA barcoding techniques to assess bat diet composition of (1) stomach contents from 47 eastern red bat ( Lasiurus borealis ) and 24 hoary bat ( Lasiurus cinereus ) carcasses collected in fatality searches, and (2) fecal pellets from 23 eastern red bats that were found on turbine towers, transformers, and tower doors. We found that the majority of the eastern red bat and hoary bat stomachs, the two bat species most commonly found in fatality searches at this site, were full or partially full, indicating that the bats were likely killed while foraging. Although Lepidoptera and Orthoptera dominated the diets of these two bat species, both consumed a range of prey items with individual bats having from one to six insect species in their stomachs at the time of death. The prey items identified from eastern red bat fecal pellets showed similar results. A comparison of the turbine insect community to the diet analysis results revealed that the most abundant insects at wind turbines, including terrestrial insects such as crickets and several

  1. Wind tunnel tests of a free yawing downwind wind turbine

    DEFF Research Database (Denmark)

    Verelst, David Robert; Larsen, Torben J.; van Wingerden, J.W.

    2012-01-01

    During February and April 2012 a series of wind tunnel tests were performed at the TU Delft Open Jet Facility (OJF) with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off the shelf three bladed hub, nacelle and generator on which relatively flexible ...... in free yawing conditions. Further, the effect of the tower shadow passage on the blade flapwise strain measurement is evaluated. Finally, data from the experiment is compared with preliminary simulations using DTU Wind Energy's aeroelastic simulation program HAWC2....... blades are mounted. The tower support structure has free yawing capabilities provided at the tower base. A short overview on the technical details of the experiment is provided as well as a brief summary of the design process. The discussed test cases show that the turbine is stable while operating...

  2. Experimental study of the influence of atmospheric conditions on the performance of natural draft dry cooling towers

    International Nuclear Information System (INIS)

    Markoczy, G.; Staempfli, E.

    1977-08-01

    The heat dissipation of cooling towers is influenced by atmospheric conditions. In order to establish these influences EIR conducted measurements on a natural draft dry cooling tower. During two measuring campaigns with a duration of total 10 weeks the performance of the cooling tower, the ambient air temperatures, the wind velocities and directions as well as air temperature at the top of the tower and in front of the heat exchangers were continuously measured and registered. The results achieved enable the quantitative description of the influence of the ambient air temperature, wind and temperature inversion on the performance of natural draft dry cooling towers. (Auth.)

  3. Unsteady aerodynamic modelling of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Coton, F.N.; Galbraith, R.A. [Univ. og Glasgow, Dept. of Aerospace Engineering, Glasgow (United Kingdom)

    1997-08-01

    The following current and future work is discussed: Collaborative wind tunnel based PIV project to study wind turbine wake structures in head-on and yawed flow. Prescribed wake model has been embedded in a source panel representation of the wind tunnel walls to allow comparison with experiment; Modelling of tower shadow using high resolution but efficient vortex model in tower shadow domain; Extension of model to yawing flow; Upgrading and tuning of unsteady aerodynamic model for low speed, thick airfoil flows. Glasgow has a considerable collection of low speed dynamic stall data. Currently, the Leishman - Beddoes model is not ideally suited to such flows. For example: Range of stall onset criteria used for dynamic stall prediction including Beddoes. Wide variation of stall onset prediction. Beddoes representation was developed primarily with reference to compressible flows. Analyses of low speed data from Glasgow indicate deficiencies in the current model; Predicted versus measured response during ramp down motion. Modification of the Beddoes representation is required to obtain a fit with the measured data. (EG)

  4. Optimal Structural Reliability of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tarp-Johansen, N.J.

    2005-01-01

    The main failure modes of modern large wind turbines are fatigue failure of wings, hub, shaft and main tower, local buckling of main tower, and failure of the foundation. This paper considers reliability-based optimal design of wind turbines. Compared to onshore wind turbines and building...... structures, humans spent little time in the vicinity of offshore wind turbines and the probability of human injury during storm conditions is small. Further environmental pollution will also in general be small in case of failure. One could therefore argue that the reliability level of offshore wind turbines...... can be lower than for onshore wind turbines and other civil engineering structures and can be assessed by reliability-based cost-optimization. Specifically this paper considers the main tower and foundation. Both fatigue and ultimate strength failure modes are included. Different formulations...

  5. Wind power and bird kills

    International Nuclear Information System (INIS)

    Raynolds, M.

    1998-01-01

    The accidental killing of birds by wind generators, and design improvements in the towers that support the turbines that might cut down on the bird killings were discussed. The first problem for the industry began in the late 1980s when the California Energy Commission reported as many as 160 birds (the majority being raptors, including the protected golden eagle) killed in one year in the vicinity of wind power plants. The key factor identified was the design of the towers as birds of prey are attracted to lattice towers as a place to hunt from. Tubular towers do not provide a place for the birds to perch, therefore they reduce the potential for bird strikes. Bird strikes also have been reported in Spain and the siting of the towers have been considered as the principal cause of the bird strikes. In view of these incidents, the wind power industry is developing standards for studying the potential of bird strikes and is continuing to study bird behaviour leading to collisions, the impact of topography, cumulative impacts and new techniques to reduce bird strikes. Despite the reported incidents, the risk of bird strikes by wind turbines, compared to other threats to birds such as pollution, oil spills, and other threats from fossil and nuclear fuels, is considered to be negligible. With continuing efforts to minimize incidents by proper design and siting, wind power can continue to grow as an environmentally sound and efficient source of energy

  6. Wind power and bird kills

    Energy Technology Data Exchange (ETDEWEB)

    Raynolds, M.

    1998-12-01

    The accidental killing of birds by wind generators, and design improvements in the towers that support the turbines that might cut down on the bird killings were discussed. The first problem for the industry began in the late 1980s when the California Energy Commission reported as many as 160 birds (the majority being raptors, including the protected golden eagle) killed in one year in the vicinity of wind power plants. The key factor identified was the design of the towers as birds of prey are attracted to lattice towers as a place to hunt from. Tubular towers do not provide a place for the birds to perch, therefore they reduce the potential for bird strikes. Bird strikes also have been reported in Spain and the siting of the towers have been considered as the principal cause of the bird strikes. In view of these incidents, the wind power industry is developing standards for studying the potential of bird strikes and is continuing to study bird behaviour leading to collisions, the impact of topography, cumulative impacts and new techniques to reduce bird strikes. Despite the reported incidents, the risk of bird strikes by wind turbines, compared to other threats to birds such as pollution, oil spills, and other threats from fossil and nuclear fuels, is considered to be negligible. With continuing efforts to minimize incidents by proper design and siting, wind power can continue to grow as an environmentally sound and efficient source of energy.

  7. Alternative geometry for cylindrical natural draft cooling tower with higher cooling efficiency under crosswind condition

    International Nuclear Information System (INIS)

    Goodarzi, M.; Ramezanpour, R.

    2014-01-01

    Highlights: • Alternative cross sections for natural draft cooling tower were proposed. • Numerical solution was applied to study thermal and hydraulic performances. • Thermal and hydraulic performances were assessed by comparative parameters. • Cooling tower with elliptical cross section had better thermal performance under crosswind. • It could successfully used at the regions with invariant wind direction. - Abstract: Cooling efficiency of a natural draft dry cooling tower may significantly decrease under crosswind condition. Therefore, many researchers attempted to improve the cooling efficiency under this condition by using structural or mechanical facilities. In this article, alternative shell geometry with elliptical cross section is proposed for this type of cooling tower instead of usual shell geometry with circular cross section. Thermal performance and cooling efficiency of the two types of cooling towers are numerically investigated. Numerical simulations show that cooling tower with elliptical cross section improves the cooling efficiency compared to the usual type with circular cross section under high-speed wind moving normal to the longitudinal diameter of the elliptical cooling tower

  8. Structure of natural draft cooling towers, 1

    International Nuclear Information System (INIS)

    Ishioka, Hitoshi; Sakamoto, Yukichi; Tsurusaki, Mamoru; Koshizawa, Koichi; Chiba, Toshio

    1976-01-01

    Thousands of natural draft cooling towers have been utilized, in Europe and America, as cooling systems of power plants or as countermeasures against thermal polution. Recently in Japan, demands for cooling tower systems have been increasing remarkably with the construction of large power plants and the legislation of environmental regulations. In view of the severe natural conditions in Japan such as strong wind and seismic loadings, etc., the establishment of the optimum design and construction method is essential for the building of safe and economical towers. In order to establish a comprehensive plan of a power plant cooling system of the appropriate structural type, the authors have made researches and experiments on design conditions, static and dynamic analyses, and comparative studies of various structural types such as reinforced concrete thin-shell structures, steel framed structures and composite shell segment structures, based on the investigation results of towers in Europe and America. These results are presented in three reports, the 1st of which concerns cooling tower shells as are hereinafter described. (auth.)

  9. Regional Analysis of Long-term Local and Synoptic Effects on Wind Velocity and Energy Patterns in Complex Terrain

    Science.gov (United States)

    Belu, R.; Koracin, D. R.

    2017-12-01

    Investments in renewable energy are justified in both environmental and economic terms. Climate change risks call for mitigation strategies aimed to reduce pollutant emissions, while the energy supply is facing high uncertainty by the current or future global economic and political contexts. Wind energy is playing a strategic role in the efforts of any country for sustainable development and energy supply security. Wind energy is a weather and climate-dependent resource, having a natural spatio-temporal variability at time scales ranging from fraction of seconds to seasons and years, while at spatial scales is strongly affected by the topography and vegetation. Main objective of the study is to investigate spatio-temporal characteristics of the wind velocity in the Southwest U.S., that are relevant to wind energy assessment, analysis, development, operation, and grid integration, by using long-term multiple meteorological tower observations. Wind velocity data and other meteorological parameters from five towers, located near Tonopah, Nevada, operated between 2003 to 2008, and from three towers are located in Carson Valley, Nevada, operated between 2006 and 2014 were used in this study. Multi-annual wind speed data collected did not show significant increase trends with increasing elevation; the differences are mainly governed by the topographic complexity, including local atmospheric circulations. Auto- and cross-correlations show a strong coherence between the wind speed and direction with slowly decreasing amplitude of the multi-day periodicity with increasing lag periods. Besides pronounced diurnal periodicity at all locations, detrended fluctuation analysis also showed significant seasonal and annual periodicities, and long-memory persistence with similar characteristics. In spite of significant differences in mean wind speeds among the towers, due to location specifics, the relatively high auto- and cross-correlation coefficients among the towers indicate

  10. Natural-draught cooling towers made of reinforced concrete

    International Nuclear Information System (INIS)

    Kraetzig, W.B.; Peters, H.L.; Zerna, W.

    1978-01-01

    Large power plant units and dry cooling tower technology require larger dimensions for natural-draught cooling towers. The main curvation radii in latitudinal and meridian direction are thus increased, which results in a lower three-dimensional support strength. This development is an incentive for constant re-consideration of calculation methods, safety philosophy, and dimensioning criteria. In this context, wind effects have been re-formulated and given a scientific foundation. Constructional measures to improve the static and dynamic behaviour of the structure have been presented and critically assessed. A cost analysis, finally, gave the most rational applications of the new shell construction with reinforcing elements. A cooling tower now under construction gave a realistic example. Fundamental aspects concerning the foundations of cooling tower shells and two special types of foundation are further points to clarify the subject. (orig./HP) [de

  11. Wind Resource Assessment and Requested Wind Turbine Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Ken [Municipal Civil Corporation, Gas City, IN (United States); Wolar, John [Municipal Civil Corporation, Gas City, IN (United States)

    2012-10-22

    Alternate Energy Solutions, Inc. (“AESWR”) was engaged by the Town of Brookston (“Brookston”) to assemble, erect and maintain one 60 m XHD meteorological tower manufactured by NRG Systems, Inc.; for monitoring, recording and evaluating collected wind data. It is the opinion of AESWR staff that study results support the development of a wind turbine project at the Bol Family Farm provided: a) additional land is leased for the project; b) project construction costs are controlled; and c) a prudent power purchase agreement is negotiated with a power take-off entity. We believe that a project having an aggregate nameplate rating sized from 6.0 MW to 20 MW would be appropriate for this location. We recommend 100-125 acres of land per installed MW be used as a general rule for acquiring wind energy land lease agreements, total land lease holdings to be acquired would then approach 750 acres to 2,500 acres.

  12. Steel Towers for Wind Turbines

    OpenAIRE

    Matos, Rui Manuel Maia Pinto de

    2017-01-01

    Tese de doutoramento em Construção Metálica e Mista, apresentada ao Departamento de Engenharia Civil da Faculdade de Ciências e Tecnologia da Universidade de Coimbra In the last few years it was registered an increase in the exploitation of renewable energies, namely wind energy, due to the increasing concern about the environmental problems related with the global warming. The forecast of the official entities is to increase the exploitation of the wind energy of around 61% in the Europe...

  13. Fatigue Life of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    2010-01-01

    The present paper analyses the possibility of reducing the expected damage accumulation during tower passage by modifying the wind turbine tower design from a traditional mono-tower to a tripod. Due to a narrow stagnation zone the stress reversals and hence the damage accumulation in the blades...

  14. Reliability Analysis of Wind Turbines

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2008-01-01

    In order to minimise the total expected life-cycle costs of a wind turbine it is important to estimate the reliability level for all components in the wind turbine. This paper deals with reliability analysis for the tower and blades of onshore wind turbines placed in a wind farm. The limit states...... consideres are in the ultimate limit state (ULS) extreme conditions in the standstill position and extreme conditions during operating. For wind turbines, where the magnitude of the loads is influenced by the control system, the ultimate limit state can occur in both cases. In the fatigue limit state (FLS......) the reliability level for a wind turbine placed in a wind farm is considered, and wake effects from neighbouring wind turbines is taken into account. An illustrative example with calculation of the reliability for mudline bending of the tower is considered. In the example the design is determined according...

  15. GPM GROUND VALIDATION METEOROLOGICAL TOWER ENVIRONMENT CANADA GCPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation Meteorological Tower Environment Canada GCPEx dataset provides temperature, relative humidity, 10 m winds, pressure and solar radiation...

  16. The effect of a tall tower on flow and dispersion through a model urban neighborhood: part 2. Pollutant dispersion.

    Science.gov (United States)

    Brixey, Laurie A; Heist, David K; Richmond-Bryant, Jennifer; Bowker, George E; Perry, Steven G; Wiener, Russell W

    2009-12-01

    This article is the second in a two-paper series presenting results from wind tunnel and computational fluid dynamics (CFD) simulations of flow and dispersion in an idealized model urban neighborhood. Pollutant dispersion results are presented and discussed for a model neighborhood that was characterized by regular city blocks of three-story row houses with a single 12-story tower located at the downwind edge of one of these blocks. The tower had three significant effects on pollutant dispersion in the surrounding street canyons: drawing the plume laterally towards the tower, greatly enhancing the vertical dispersion of the plume in the wake of the tower, and significantly decreasing the residence time of pollutants in the wake of the tower. In the wind tunnel, tracer gas released in the avenue lee of the tower, but several blocks away laterally, was pulled towards the tower and lifted in the wake of the tower. The same lateral movement of the pollutant was seen in the next avenue, which was approximately 2.5 tower heights downwind of the tower. The tower also served to ventilate the street canyon directly in its wake more rapidly than the surrounding areas. This was evidenced by CFD simulations of concentration decay where the residence time of pollutants lee of the 12-story tower was found to be less than half the residence time behind a neighboring three-story building. This same phenomenon of rapid vertical dispersion lee of a tower among an array of smaller buildings was also demonstrated in a separate set of wind tunnel experiments using an array of cubical blocks. A similar decrease in the residence time was observed when the height of one block was increased.

  17. Wind tunnel tests of a free yawing downwind wind turbine

    DEFF Research Database (Denmark)

    Verelst, David Robert; Larsen, Torben J.; van Wingerden, Jan-Willem

    2014-01-01

    . The discussed test cases show that the turbine is stable while operating in free yawing conditions. Further, the effect of the tower shadow passage on the blade flapwise strain measurement is evaluated. Finally, data from the experiment is compared with preliminary simulations using DTU Wind Energy......This research paper presents preliminary results on a behavioural study of a free yawing downwind wind turbine. A series of wind tunnel tests was performed at the TU Delft Open Jet Facility with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off...... the shelf three bladed hub, nacelle and generator on which relatively flexible blades are mounted. The tower support structure has free yawing capabilities provided at the base. A short overview on the technical details of the experiment is given as well as a brief summary of the design process...

  18. Transportation of Large Wind Components: A Review of Existing Geospatial Data

    Energy Technology Data Exchange (ETDEWEB)

    Mooney, Meghan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Maclaurin, Galen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    This report features the geospatial data component of a larger project evaluating logistical and infrastructure requirements for transporting oversized and overweight (OSOW) wind components. The goal of the larger project was to assess the status and opportunities for improving the infrastructure and regulatory practices necessary to transport wind turbine towers, blades, and nacelles from current and potential manufacturing facilities to end-use markets. The purpose of this report is to summarize existing geospatial data on wind component transportation infrastructure and to provide a data gap analysis, identifying areas for further analysis and data collection.

  19. Wintering Sandhill Crane exposure to wind energy development in the central and southern Great Plains, USA

    Science.gov (United States)

    Pearse, Aaron T.; Brandt, David; Krapu, Gary

    2016-01-01

    Numerous wind energy projects have been constructed in the central and southern Great Plains, USA, the main wintering area for midcontinental Sandhill Cranes (Grus canadensis). In an initial assessment of the potential risks of wind towers to cranes, we estimated spatial overlap, investigated potential avoidance behavior, and determined the habitat associations of cranes. We used data from cranes marked with platform transmitting terminals (PTTs) with and without global positioning system (GPS) capabilities. We estimated the wintering distributions of PTT-marked cranes prior to the construction of wind towers, which we compared with current tower locations. Based on this analysis, we found 7% spatial overlap between the distributions of cranes and towers. When we looked at individually marked cranes, we found that 52% would have occurred within 10 km of a tower at some point during winter. Using data from cranes marked after tower construction, we found a potential indication of avoidance behavior, whereby GPS-marked cranes generally used areas slightly more distant from existing wind towers than would be expected by chance. Results from a habitat selection model suggested that distances between crane locations and towers may have been driven more by habitat selection than by avoidance, as most wind towers were constructed in locations not often selected by wintering cranes. Our findings of modest regional overlap and that few towers have been placed in preferred crane habitat suggest that the current distribution of wind towers may be of low risk to the continued persistence of wintering midcontinental Sandhill Cranes in the central and southern Great Plains.

  20. Comparative study on thermal performance of natural draft cooling towers with finned shells

    International Nuclear Information System (INIS)

    Goodarzi, Mohsen

    2016-01-01

    The cooling efficiency of natural draft cooling towers under crosswind condition should be improved. In the present research work three different externally finned shells were considered for a typical natural draft cooling tower to investigate the cooling improvement. They were numerically simulated under normal and crosswind conditions. Numerical results show that twisting four fin plates over the tower shell along the 45 peripheral angle, could improve the cooling efficiency up to 6.5 %. Because of the periodic shape of the fin plates, the cooling efficiency of the cooling tower with finned shell is less sensitive to the change of wind.

  1. Comparative study on thermal performance of natural draft cooling towers with finned shells

    Energy Technology Data Exchange (ETDEWEB)

    Goodarzi, Mohsen [Bu-Ali Sina Univ., Hamedan (Iran, Islamic Republic of). Dept. of Mechanical Engineering

    2016-10-15

    The cooling efficiency of natural draft cooling towers under crosswind condition should be improved. In the present research work three different externally finned shells were considered for a typical natural draft cooling tower to investigate the cooling improvement. They were numerically simulated under normal and crosswind conditions. Numerical results show that twisting four fin plates over the tower shell along the 45 peripheral angle, could improve the cooling efficiency up to 6.5 %. Because of the periodic shape of the fin plates, the cooling efficiency of the cooling tower with finned shell is less sensitive to the change of wind.

  2. TacTower

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegaard; Jürgensen, Christine

    2009-01-01

    Learning from the multiplayer interaction in sports, we describe our project TacTower; a flexible system for professional elite handball players to train game perception and kinesthetic em- pathy. The design is founded in ideas of Collective Interaction and qualities that is inherent in sport...

  3. Dry cooling tower operating experience in the LOFT reactor

    International Nuclear Information System (INIS)

    Hunter, J.A.

    1980-01-01

    A dry cooling tower has been uniquely utilized to dissipate heat generated in a small experimental pressurized water nuclear reactor. Operational experience revealed that dry cooling towers can be intermittently operated with minimal wind susceptibility and water hammer occurrences by cooling potential steam sources after a reactor scram, by isolating idle tubes from the external atmosphere, and by operating at relatively high pressures. Operating experience has also revealed that tube freezing can be minimized by incorporating the proper heating and heat loss prevention features

  4. Added damping of a wind turbine rotor : Two-dimensional discretization expressing the nonlinear wind-force dependency

    NARCIS (Netherlands)

    Van der Male, P.; Van Dalen, K.N.; Metrikine, A.

    2014-01-01

    In determining wind forces on wind turbine blades, and subsequently on the tower and the foundation, the blade response velocity cannot be neglected. This velocity alters the wind force, which depends on the wind velocity relative to that of the blades This blade response velocity component of the

  5. Wind power. [electricity generation

    Science.gov (United States)

    Savino, J. M.

    1975-01-01

    A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

  6. Wind Climate Analyses for SRTC's Central Climatology Site

    International Nuclear Information System (INIS)

    Weber, A.H.

    2003-01-01

    This report was written to present climatological summaries of the wind data at the Central Climatology (CC) tower in a convenient format and to point out some features of the wind speed and direction that have not been widely appreciated in the past. Short-term (two-week) wind roses provide a means to demonstrate the temporal and spatial relationships that wind speed and direction undergo using a ten-year database from the CC tower. These relationships are best demonstrated by examining the figures provided in this report or looking at loops of computer-generated images provided by the authors

  7. Wind Data Analysis and Wind Flow Simulation Over Large Areas

    Directory of Open Access Journals (Sweden)

    Terziev Angel

    2014-03-01

    Full Text Available Increasing the share of renewable energy sources is one of the core policies of the European Union. This is because of the fact that this energy is essential in reducing the greenhouse gas emissions and securing energy supplies. Currently, the share of wind energy from all renewable energy sources is relatively low. The choice of location for a certain wind farm installation strongly depends on the wind potential. Therefore the accurate assessment of wind potential is extremely important. In the present paper an analysis is made on the impact of significant possible parameters on the determination of wind energy potential for relatively large areas. In the analysis the type of measurements (short- and long-term on-site measurements, the type of instrumentation and the terrain roughness factor are considered. The study on the impact of turbulence on the wind flow distribution over complex terrain is presented, and it is based on the real on-site data collected by the meteorological tall towers installed in the northern part of Bulgaria. By means of CFD based software a wind map is developed for relatively large areas. Different turbulent models in numerical calculations were tested and recommendations for the usage of the specific models in flows modeling over complex terrains are presented. The role of each parameter in wind map development is made. Different approaches for determination of wind energy potential based on the preliminary developed wind map are presented.

  8. Economic viability of ultra high-performance fiber reinforced concrete in prestressed concrete wind towers to support a 5 MW turbine

    Directory of Open Access Journals (Sweden)

    P. V. C. N. GAMA

    Full Text Available Abstract The Ultra-High Performance Fiber-Reinforced Concrete is a material with remarkable mechanical properties and durability when compared to conventional and high performance concrete, which allows its use even without the reinforcement. This paper proposes the design of prestressed towers for a 5 MW turbine, through regulatory provisions and the limit states method, with UHPFRC and the concrete class C50, comparing the differences obtained in the design by parametric analysis, giving the advantages and disadvantages of using this new type of concrete. Important considerations, simplifications and notes are made to the calculation process, as well as in obtaining the prestressing and passive longitudinal and passive transverse reinforcement, highlighting the shear strength of annular sections comparing a model proposed here with recent experimental results present in the literature, which was obtained good agreement. In the end, it is estimated a first value within the constraints here made to ensure the economic viability of the use of UHPFRC in a 100 m prestressed wind tower with a 5 MW turbine.

  9. Wind instrument mountings for above-the-cab lookout exposure

    Science.gov (United States)

    Owen P. Cramer; Ralph H. Moltzau

    1968-01-01

    The lookout tower offers a ready-made platform from which the speed of true unobstructed wind can be measured, then reduced to equivalent of 20-foot wind. Tower-mounted instruments must meet the requirements of a lightning conductor system, but should also be easily installed and removed for storage and maintenance. Lightweight aluminum mountings for catwalk or flat-...

  10. Gradient-Based Optimization of Wind Farms with Different Turbine Heights

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, Andrew P. J.; Thomas, Jared; Ning, Andrew; Annoni, Jennifer; Dykes, Katherine; Fleming, Paul

    2017-01-09

    Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5%-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and a low wind shear exponent.

  11. Wind turbine having a direct-drive drivetrain

    Science.gov (United States)

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2008-10-07

    A wind turbine (100) comprising an electrical generator (108) that includes a rotor assembly (112). A wind rotor (104) that includes a wind rotor hub (124) is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle (160) via a bearing assembly (180). The wind rotor hub includes an opening (244) having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity (380) inside the wind rotor hub. The spindle is attached to a turret (140) supported by a tower (136). Each of the spindle, turret and tower has an interior cavity (172, 176, 368) that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system (276) for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  12. Wind energy centre at Mithapur, Gujarat, India. Technical report

    International Nuclear Information System (INIS)

    Van Hulle, F.; Van der Borg, N.; Prasad, N.S.; Suresh, R.; Rajsekhar, B.

    1997-07-01

    The report describes the design and set-up of a Wind Energy Centre in Gujarat. This Wind Energy Centre has to provide a reliable delivery of a range of development and technical quality assurance services to the wind energy industry in northern India. Infrastructural and organizational requirements of the centre have been defined as per the demands expressed by the industry. This include, site and land, building, equipment - hardware/software, manpower, etc. A suitable site has been identified on the western coast of Gujarat (in the vicinity of Mithapur). Based on the feedback from the industry and keeping in mind the possibilities and state-of-the-art followed in intemationally accepted centres, a range of activities including research and development, support to indigenisation, testing and certification, as well as training have been addressed. Facilities include the following: (1) Test site: test pads, building, roads, power collection system, meteo-towers etc; (2) Mobile test equipment: basic measurement sets, transportable meteo-towers, auxiliary equipment; and (3) Blade test facility: building, foundation, loading and measuring facilities. At full capacity the centre will employ approximately 20 people. 3 figs., 4 tabs

  13. Crack Monitoring of Operational Wind Turbine Foundations.

    Science.gov (United States)

    Perry, Marcus; McAlorum, Jack; Fusiek, Grzegorz; Niewczas, Pawel; McKeeman, Iain; Rubert, Tim

    2017-08-21

    The degradation of onshore, reinforced-concrete wind turbine foundations is usually assessed via above-ground inspections, or through lengthy excavation campaigns that suspend wind power generation. Foundation cracks can and do occur below ground level, and while sustained measurements of crack behaviour could be used to quantify the risk of water ingress and reinforcement corrosion, these cracks have not yet been monitored during turbine operation. Here, we outline the design, fabrication and field installation of subterranean fibre-optic sensors for monitoring the opening and lateral displacements of foundation cracks during wind turbine operation. We detail methods for in situ sensor characterisation, verify sensor responses against theoretical tower strains derived from wind speed data, and then show that measured crack displacements correlate with monitored tower strains. Our results show that foundation crack opening displacements respond linearly to tower strain and do not change by more than ±5 μ m. Lateral crack displacements were found to be negligible. We anticipate that the work outlined here will provide a starting point for real-time, long-term and dynamic analyses of crack displacements in future. Our findings could furthermore inform the development of cost-effective monitoring systems for ageing wind turbine foundations.

  14. Data from an instrumented navigational light tower off the Savanah River estuary

    International Nuclear Information System (INIS)

    Hayes, D.W.; Dicks, A.S.; Blanton, J.O.

    1978-01-01

    An oceanographic and meteorological instrumentation system operating on the Savannah Navigational Light Tower is providing synoptic information on ocean temperatures, currents, tides, and meteorological conditions. The Savannah Navigational Light Tower, an unmanned U.S. Coast Guard tower, is located about nine miles off Savannah Beach, Georgia, in about 16 m of water. The tower is currently instrumented to measure and record water temperatures from six depths, water velocities at two depts, tides, air temperature, barometric pressure, and wind speed and velocity at two heights. The outputs are currently being recorded every 10 minutes. These data aid in the interpretation of the processes governing pollutant transport in the Savannah River marine region and support other DOE funded programs in the southeastern United States. This past year, computer programs were written and are being tested for processing the raw data from the tower and for performing correlative analysis of the data

  15. Solar tower enhanced natural draft dry cooling tower

    Science.gov (United States)

    Yang, Huiqiang; Xu, Yan; Acosta-Iborra, Alberto; Santana, Domingo

    2017-06-01

    Concentrating Solar Power (CSP) plants are located in desert areas where the Direct Normal Irradiance (DNI) value is very high. Since water resource is scarcely available, mechanical draft cooing technology is commonly used, with power consumption of mechanical fans being approximately 2% of the total power generated. Today, there is only one solar power plant (Khi Solar One in South Africa) uses a condenser installed in a Natural Draft Cooling (NDC) tower that avoids the windage loss of water occurring in wet cooling towers. Although, Khi Solar One is a cavity receiver power tower, the receivers can be hung onto the NDC tower. This paper looks at a novel integration of a NDC tower into an external molten salt receiver of a solar power plant, which is one of a largest commercial molten salt tower in China, with 100MWe power capacity. In this configuration study, the NDC tower surrounds the concrete tower of the receiver concentrically. In this way, the receiver concrete tower is the central support of the NDC tower, which consists of cable networks that are fixed to the concrete tower and suspended at a certain height over the floor. The cable networks support the shell of the NDC tower. To perform a preliminary analysis of the behavior of this novel configuration, two cases of numerical simulation in three dimensional (3D) models have been solved using the commercial Computational Fluid Dynamics (CFD) code, ANSYS Fluent 6.3. The results show that the integration of the NDC tower into an external central receiver tower is feasible. Additionally, the total heat transfer rate is not reduced but slightly increases when the molten salt receiver is in operation because of the additional natural draft induced by the high temperature of the receiver.

  16. Adaptive inflatable structures for protecting wind turbines against ship collisions

    Energy Technology Data Exchange (ETDEWEB)

    Graczykowski, C.; Heinonen, J.

    2006-09-15

    Collisions of small ships are one of main dangers for the offshore wind turbines. Using inflatable structures surrounding the tower on the water level is a possibility of effective protection. Modelling of such structures is based on interaction between solid wall and fluid enclosed inside. Inflatable structures can be adapted to various impact schemes by adjusting initial pressure and controlling release of compressed air by opening piezo-valves. Simulations of ship collision with 2D model of wind turbine tower protected by pneumatic structure are presented in the report. Numerical analysis is performed using ABAQUS/Standard and ABAQUS/Explicit. Performed feasibility study proves that inflatable structures can protect wind turbine tower and ship against serious damages. (orig.)

  17. Acidity of vapor plume from cooling tower mixed with flue gases emitted from coal-fired power plant.

    Science.gov (United States)

    Hlawiczka, Stanislaw; Korszun, Katarzyna; Fudala, Janina

    2016-06-01

    Acidity of products resulting from the reaction of flue gas components emitted from a coal-fired power plant with water contained in a vapor plume from a wet cooling tower was analyzed in a close vicinity of a power plant (710 m from the stack and 315 m from the cooling tower). Samples of this mixture were collected using a precipitation funnel where components of the mixed plumes were discharged from the atmosphere with the rainfall. To identify situations when the precipitation occurred at the same time as the wind directed the mixed vapor and flue gas plumes above the precipitation funnel, an ultrasound anemometer designed for 3D measurements of the wind field located near the funnel was used. Precipitation samples of extremely high acidity were identified - about 5% of samples collected during 12 months showed the acidity below pH=3 and the lowest recorded pH was 1.4. During the measurement period the value of pH characterizing the background acidity of the precipitation was about 6. The main outcome of this study was to demonstrate a very high, and so far completely underestimated, potential of occurrence of episodes of extremely acid depositions in the immediate vicinity of a coal-fired power plant. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Gradient-Based Optimization of Wind Farms with Different Turbine Heights: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Stanley, Andrew P. J.; Thomas, Jared; Ning, Andrew; Annoni, Jennifer; Dykes, Katherine; Fleming, Paul

    2017-05-08

    Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5%-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and a low wind shear exponent.

  19. Hybrid damper with stroke amplification for damping of offshore wind turbines

    DEFF Research Database (Denmark)

    Brodersen, Mark L.; Høgsberg, Jan

    2016-01-01

    tower. The proposed hybrid damper consists of a passive viscous dashpot placed in series with a load cell and an active actuator. By integrated force feedback control of the actuator motion, the associated displacement amplitude over the viscous damper can be increased compared with the passive viscous......The magnitude of tower vibrations of offshore wind turbines is a key design driver for the feasibility of the monopilesupport structure. A novel control concept for the damping of these tower vibrations is proposed, where viscous-type hybrid dampers are installed at the bottom of the wind turbine...... case, hereby significantly increasing the feasibility of viscous dampers acting at the bottom of the wind turbine tower. To avoid drift in the actuator displacement, a filtered time integration of the measured force signal is introduced. Numerical examples demonstrate that the filtered time integration...

  20. Lightweight structure design for wind energy by integrating nanostructured materials

    International Nuclear Information System (INIS)

    Li, Ying; Lu, Jian

    2014-01-01

    Highlights: • Integrate high-strength nano-materials into lightweight design. • Lightweight design scheme for wind turbine tower application. • Expand the bending formulae for tapered tubular structures with varying thickness. • We rewrite the Secant Formula for a tapered beam under eccentric compression. - Abstract: Wind power develops very fast nowadays with high expectation. Although at the mean time, the use of taller towers, however, smacks head-on into the issue of transportability. The engineering base and computational tools have to be developed to match machine size and volume. Consequently the research on the light weight structures of tower is carrying out in the main countries which are actively developing wind energy. This paper reports a new design scheme of light weight structure for wind turbine tower. This design scheme is based on the integration of the nanostructured materials produced by the Surface Mechanical Attrition Treatment (SMAT) process. The objective of this study is to accomplish the weight reduction by optimizing the wall thickness of the tapered tubular structure. The basic methods include the identification of the critical zones and the distribution of the high strength materials according to different necessities. The equivalent strength or stiffness design method and the high strength material properties after SMAT process are combined together. Bending and buckling are two main kinds of static loads concerned in consideration. The study results reveal that there is still enough margin for weight reduction in the traditional wind turbine tower design

  1. An experimental study on natural draft-dry cooling tower as part of the passive system for the residual decay heat removal

    International Nuclear Information System (INIS)

    Caruso, G.; Fatone, M.; Naviglio, A.

    2007-01-01

    An experimental apparatus has been built in order to perform sensitivity analysis on the performance of a natural draft-dry cooling tower. This component plays an important role in the passive system for the residual heat decay removal foreseen in the MARS reactor and in the GCFR of the Generation IV reactors. The sensitivity analysis has investigated: 1) the heat exchanger arrangement; two different arrangements have been considered: a horizontal arrangement, in which a system of electrical heaters are placed at the inlet cross section of the tower, and a vertical arrangement, with the heaters distributed vertically around the circumference of the tower. 2) The shape of the cooling tower; by varying the angle of the shell inclination it is possible to obtain a different shape for the tower itself. An upper and a lower angle inclination were modified and by a calculation procedure eleven different configuration were selected. 3) The effect of cross wind on the tower performance. An equation-based procedure to design the dry-cooling tower is presented. In order to evaluate the influence of the shape and the heat exchanger arrangement on the performance of the cooling tower, a geometrical factor (FG) and a thermal factor (FT) are introduced. By analyzing the experimental results, engineering design relations are obtained to model the cooling tower performance. The comparison between the experimental heat transfer coefficient and the heat transfer coefficient obtained by the mathematical procedure shows that there is a good agreement. The obtained results show that it is possible to evaluate the shape and the heat exchanger arrangement to optimize the performance of the cooling tower either in wind-less condition either in presence of cross wind. (authors)

  2. Wind Spires as an Alternative Energy Source

    Energy Technology Data Exchange (ETDEWEB)

    Majid Rashidi, Ph.D., P.E.

    2012-10-30

    This report discloses the design and development of an innovative wind tower system having an axisymmetric wind deflecting structure with a plurality of symmetrically mounted rooftop size wind turbines near the axisymmetric structure. The purpose of the wind deflecting structure is to increase the ambient wind speed that in turn results in an overall increase in the power capacity of the wind turbines. Two working prototypes were constructed and installed in the summer of 2009 and 2012 respectively. The system installed in the Summer of 2009 has a cylindrical wind deflecting structure, while the tower installed in 2012 has a spiral-shape wind deflecting structure. Each tower has 4 turbines, each rated at 1.65 KW Name-Plate-Rating. Before fabricating the full-size prototypes, computational fluid dynamic (CFD) analyses and scaled-down table-top models were used to predict the performance of the full-scale models. The performance results obtained from the full-size prototypes validated the results obtained from the computational models and those of the scaled-down models. The second prototype (spiral configuration) showed at a wind speed of 11 miles per hour (4.9 m/s) the power output of the system could reach 1,288 watt, when a typical turbine installation, with no wind deflecting structure, could produce only 200 watt by the same turbines at the same wind speed. At a wind speed of 18 miles per hour (8 m/sec), the spiral prototype produces 6,143 watt, while the power generated by the same turbines would be 1,412 watt in the absence of a wind deflecting structure under the same wind speed. Four US patents were allowed, and are in print, as the results of this project (US 7,540,706, US 7,679,209, US 7,845,904, and US 8,002,516).

  3. Wind turbine spoiler

    Science.gov (United States)

    Sullivan, W.N.

    An aerodynamic spoiler system for a vertical axis wind turbine includes spoilers on the blades initially stored near the rotor axis to minimize drag. A solenoid latch adjacent the central support tower releases the spoilers and centrifugal force causes the spoilers to move up the turbine blades away from the rotor axis, thereby producing a braking effect and actual slowing of the associated wind turbine, if desired. The spoiler system can also be used as an infinitely variable power control by regulated movement of the spoilers on the blades over the range between the undeployed and fully deployed positions. This is done by the use of a suitable powered reel and cable located at the rotor tower to move the spoilers.

  4. Session: What have studies of communications towers suggested regarding the impact of guy wires and lights on birds and bats

    Energy Technology Data Exchange (ETDEWEB)

    Kerlinger, Paul

    2004-09-01

    This session at the Wind Energy and Birds/Bats workshop consisted of one presentation followed by a discussion/question and answer period. The paper ''Wind turbines and Avian Risk: Lessons from Communications Towers'' was given by Paul Kerlinger. The presenter outlined lessons that have been learned from research on communications (not cell) towers and about the impacts of guy wires and lights on birds and bats and how they could be useful to wind energy developers. The paper also provided specific information about a large 'fatality' event that occurred at the Mountaineer, WC wind energy site in May 2003, and a table of Night Migrant Carcass search findings for various wind sites in the US.

  5. Numerical Estimation of Fatigue Life of Wind Turbines due to Shadow Effect

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Pedersen, Ronnie; Nielsen, Søren R.K.

    2009-01-01

    The influence of tower design on damage accumulation in up-wind turbine blades during tower passage is discussed. The fatigue life of a blade is estimated for a tripod tower configuration and a standard mono-tower. The blade stresses are determined from a dynamic mechanical model with a delay...

  6. Downscaling of Airborne Wind Energy Systems

    NARCIS (Netherlands)

    Fechner, U.; Schmehl, R.

    2016-01-01

    Airborne wind energy systems provide a novel solution to harvest wind energy from altitudes that can not be reached by wind turbines with a similar nominal generator power. The use of a lightweight but strong tether in place of an expensive tower provides an additional cost advantage, next to the

  7. Wind turbine/generator set and method of making same

    Science.gov (United States)

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2013-06-04

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  8. TacTower

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegaard; Jürgensen, Christine

    2009-01-01

    Learning from the multiplayer interaction in sports, we describe our project TacTower; a flexible system for professional elite handball players to train game perception and kinesthetic em- pathy. The design is founded in ideas of Collective Interaction and qualities that is inherent in sport...... and is based on consid- erations about paralanguage, kinesthetic emphatic interaction, physical positioning of players and collaborative interaction....

  9. 76 FR 10328 - Grant of Authority for Subzone Status; Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs...

    Science.gov (United States)

    2011-02-24

    ... Status; Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs, Blades and Towers), Brighton, Denver...-purpose subzone at the wind turbine nacelle, hub, blade and tower manufacturing and warehousing facilities... status for activity related to the manufacturing and warehousing of wind turbine nacelles, hubs, blades...

  10. Wind Turbine With Concentric Ducts

    Science.gov (United States)

    Muhonen, A. J.

    1983-01-01

    Wind Turbine device is relatively compact and efficient. Converging inner and outer ducts increase pressure difference across blades of wind turbine. Turbine shaft drives alternator housed inside exit cone. Suitable for installation on such existing structures as water towers, barns, houses, and commercial buildings.

  11. Offshore Wind Farms

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Hasager, Charlotte Bay; Courtney, Michael

    2015-01-01

    : the rotor, the nacelle, the tower, and the foundation. Further the determinations of the essential environmental conditions are treated: the wind field, the wave field, the sea current, and the soil conditions. The various options for grid connections, advantages, and disadvantages are discussed. Of special...... concern are the problems associated with locating the turbines close together in a wind farm and the problems of placing several large wind farms in a confined area. The environmental impacts of offshore wind farms are also treated, but not the supply chain, that is, the harbors, the installation vessels...

  12. EDF's ageing management program for cooling towers

    International Nuclear Information System (INIS)

    Roure, T.; Crolet, Y.

    2015-01-01

    EDF operates a large fleet of cooling towers for its thermal and nuclear plants. Proactive maintenance strategies require ranking the towers according to the risk of failure and the observed damage. The ranking includes monitoring data such as: foundation settlements, material properties, quantified crack patterns, shell deformation, meteorological data, and corrosion. The numerical tool suite includes a finite element analysis of each tower under thermal and mechanical loadings and a corrosion predicting tool, based on carbonation. The first module computes the behavior of cooling towers under five types of loading: soil differential settlement, self-weight, moisture transport, temperature and wind. By comparison with the ultimate resisting capacity of the reinforced concrete cross section, a risk index map is produced for each tower. This risk index is used to rank the cooling towers and then to identify which structures should be monitored more closely or reinforced - if needed - first in the case of an extended operating life. The second module aims to anticipate the corrosion depth of reinforcement steel of the towers in the future. Examination of the existing carbonation is currently done for each structure and evolution of the carbonation depth is computed so as to predict with reasonable assurance when carbonation reaches the rebars. A prediction of the eventual cross-section loss of rebars is then made for long term analysis (i.e. up to 60 years of operating life). When corrosion is predicted the first module takes into account this loss and computes the behavior of the predicted corrosion damaged structure under the same loadings. (authors)

  13. Faults in the Collection Grid of Offshore Wind Farms

    DEFF Research Database (Denmark)

    Lunow, Morten Erlandsson; Holbøll, Joachim; Henriksen, Mogens

    2008-01-01

    This paper deals with transient conditions in the collection grid of offshore wind farms under different faults. A model of a standard wind farm was established in two versions, with a floating and a grounded collection grid respectively. Line to ground faults and three-phase to ground faults were...... applied at critical points at worst-case phase angle and the results compared. The simulations show that it is better with a grounded collection grid, since lack of a ground reference will prevent the system from recovering after a line to ground fault....

  14. Cooling tower practice in Germany: state of the art

    International Nuclear Information System (INIS)

    Zerna, W.; Kraetzig, W.B.; Mungan, I.

    1982-01-01

    Development in design and construction of natural draught cooling towers that has taken place in Germany is discussed. Research has been concentrated on theory and analysis of shells, on acting forces, especially on wind effects, on buckling behavior and constructional problems. An approximate earthquake analysis allows a quick estimation of seismic response. The earthquake analysis is carried out by the response-spectrum-method. All design methods develop construction methods minimizing the imperfections and their control and correction during the erection process. It is shown how by arranging stiffening rings the buckling resistance and the lowest natural frequency of this new generation of cooling towers can be improved. 13 refs

  15. Transporting method for adsorbing tower and the adsorbing tower

    International Nuclear Information System (INIS)

    Shimokawa, Nobuhiro.

    1996-01-01

    A cylindrical plastic bag is disposed to the upper surface of an adsorbing tower so as to surround a suspending piece. One opening of the bag is sealed, and other opening is secured in a sealed state to a bag holding portion disposed to glove box at a gate for the adsorbing tower box. The adsorbing tower is transported into the glove box, and after the completion of the operation of the adsorbing tower, the adsorbing tower is taken out in a state that the bag is restricted and sealed at a portion below the adsorbing tower. The bag may be made of a vinyl plastic, the bag holding portion may be a short-cylindrical protrusion, and may have an O-ring groove at the outer surface. Even if the adsorbing tower is heavy, the adsorbing tower can be carried out easily in a state where it is sealed gas tightly. (N.H.)

  16. Wind turbine model and loop shaping controller design

    Science.gov (United States)

    Gilev, Bogdan

    2017-12-01

    A model of a wind turbine is evaluated, consisting of: wind speed model, mechanical and electrical model of generator and tower oscillation model. Model of the whole system is linearized around of a nominal point. By using the linear model with uncertainties is synthesized a uncertain model. By using the uncertain model is developed a H∞ controller, which provide mode of stabilizing the rotor frequency and damping the tower oscillations. Finally is simulated work of nonlinear system and H∞ controller.

  17. Proposed Columbia Wind Farm No. 1 : Final Environmental Impact Statement, Joint NEPA/SEPA.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration; Klickitat County (Wash.)

    1995-09-01

    CARES proposes to construct and operate the 25 megawatt Columbia Wind Farm No. 1 (Project) in the Columbia Hills area of Klickitat County, Washington known as Juniper Point. Wind is not a constant resource and based on the site wind measurement data, it is estimated that the Project would generate approximately 7 average annual MWs of electricity. BPA proposes to purchase the electricity generated by the Project. CARES would execute a contractual agreement with a wind developer, to install approximately 91 wind turbines and associated facilities to generate electricity. The Project`s construction and operation would include: install concrete pier foundations for each wind turbine; install 91 model AWT-26 wind turbines using 43 m high guyed tubular towers on the pier foundations; construct a new 115/24-kv substation; construct a 149 m{sup 2} steel operations and maintenance building; install 25 pad mount transformers along the turbine access roads; install 4.0 km of underground 24 kv power collection lines to collect power from individual turbines to the end of turbine strings; install 1.2 km of underground communication and transmission lines from each turbine to a pad mount transformer; install 5.6 km of 24 kv wood pole transmission lines to deliver electricity from the pad mount transformers to the Project substation; install 3.2 km of 115 kv wood pole transmission lines to deliver electricity from the Project substation to the Public Utility District No. 1 of Klickitat County(PUD)115 kv Goldendale line; interconnect with the BPA transmission system through the Goldendale line and Goldendale substation owned by the PUD; reconstruct, upgrade, and maintain 8.0 km of existing roads; construct and maintain 6.4 km of new graveled roads along the turbine strings and to individual turbines; and install meteorological towers guyed with rebar anchors on the Project site.

  18. Reliability-Based Optimization of Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tarp-Johansen, N.J.

    2004-01-01

    Reliability-based optimization of the main tower and monopile foundation of an offshore wind turbine is considered. Different formulations are considered of the objective function including benefits and building and failure costs of the wind turbine. Also different reconstruction policies in case...

  19. DEVELOPMENT OF METHODS FOR STABILITY ANALYSIS OF TOWER CRANES

    Directory of Open Access Journals (Sweden)

    Sinel'shchikov Aleksey Vladimirovich

    2018-01-01

    Full Text Available Tower cranes are one of the main tools for execution of reloading works during construction. Design of tower cranes is carried out in accordance with RD 22-166-86 “Construction of tower cranes. Rules of analysis”, according to which to ensure stability it is required not to exceed the overturning moment upper limit. The calculation of these moments is carried out with the use of empirical coefficients and quite time-consuming. Moreover, normative methodology only considers the static position of the crane and does not take into account the presence of dynamic transients due to crane functioning (lifting and swinging of the load, boom turning and the presence of the dynamic external load (e.g. from wind for different orientations of the crane. This paper proposes a method of determining the stability coefficient of the crane based on acting reaction forces at the support points - the points of contact of wheels with the crane rail track, which allows us, at the design stage, to investigate stability of tower crane under variable external loads and operating conditions. Subject: the safety of tower cranes operation with regard to compliance with regulatory requirements of ensuring their stability both at the design stage and at the operational stage. Research objectives: increasing the safety of operation of tower cranes on the basis of improving methodology of their design to ensure static and dynamic stability. Materials and methods: analysis and synthesis of the regulatory framework and modern research works on provision of safe operation of tower cranes, the method of numerical simulation. Results: we proposed the formula for analysis of stability of tower cranes using the resulting reaction forces at the supports of the crane at the point of contact of the wheel with the rail track.

  20. Wind-Wildlife Impacts Literature Database (WILD)(Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-01-01

    The Wind-Wildlife Impacts Literature Database (WILD), developed and maintained by the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL), is comprised of over 1,000 citations pertaining to the effects of land-based wind, offshore wind, marine and hydrokinetic, power lines, and communication and television towers on wildlife.

  1. Summary of wind data from nuclear power plant sites. [USA

    Energy Technology Data Exchange (ETDEWEB)

    Verholek, M. G.

    1977-03-01

    A summary of wind data from nuclear power plant sites is presented. National Weather Service archives are an immediately obvious source of wind data, but additional data sources are also available. Utility companies proposing to build nuclear power plants are required to establish on-site meteorological monitoring programs that include towers for collecting wind and temperature data for use in environmental impact assessments. These data are available for more than one hundred planned or operating nuclear power plant sites. A list of the sites, by state, is provided in Appendix A, while Appendix B contains an alphabetical list of the sites. This site wind data provides a valuable addition to the existing NWS data sets, and significantly enlarges the multilevel data presently available. The wind data published through the NRC is assembled and assessed here in order to provide a supplement to existing data sets.

  2. Fluid-structure interaction modeling of wind turbines: simulating the full machine

    Science.gov (United States)

    Hsu, Ming-Chen; Bazilevs, Yuri

    2012-12-01

    In this paper we present our aerodynamics and fluid-structure interaction (FSI) computational techniques that enable dynamic, fully coupled, 3D FSI simulation of wind turbines at full scale, and in the presence of the nacelle and tower (i.e., simulation of the "full machine"). For the interaction of wind and flexible blades we employ a nonmatching interface discretization approach, where the aerodynamics is computed using a low-order finite-element-based ALE-VMS technique, while the rotor blades are modeled as thin composite shells discretized using NURBS-based isogeometric analysis (IGA). We find that coupling FEM and IGA in this manner gives a good combination of efficiency, accuracy, and flexibility of the computational procedures for wind turbine FSI. The interaction between the rotor and tower is handled using a non-overlapping sliding-interface approach, where both moving- and stationary-domain formulations of aerodynamics are employed. At the fluid-structure and sliding interfaces, the kinematic and traction continuity is enforced weakly, which is a key ingredient of the proposed numerical methodology. We present several simulations of a three-blade 5~MW wind turbine, with and without the tower. We find that, in the case of no tower, the presence of the sliding interface has no effect on the prediction of aerodynamic loads on the rotor. From this we conclude that weak enforcement of the kinematics gives just as accurate results as the strong enforcement, and thus enables the simulation of rotor-tower interaction (as well as other applications involving mechanical components in relative motion). We also find that the blade passing the tower produces a 10-12 % drop (per blade) in the aerodynamic torque. We feel this finding may be important when it comes to the fatigue-life analysis and prediction for wind turbine blades.

  3. Real-time monitoring and structural control of a wind turbine using a rocking system

    DEFF Research Database (Denmark)

    Caterino, Nicola; Spizzuoco, Mariacristina; Georgakis, Christos T.

    2016-01-01

    The design of a semi-active (SA) control system to mitigate wind induced structural demand to high wind turbine towers is discussed herein. A variable restraint at the base, able to modify in real time its mechanical properties according to the instantaneous response of the tower, is proposed...

  4. Models for wind turbines - a collection

    DEFF Research Database (Denmark)

    2002-01-01

    This report is a collection of notes which were intended to be short communications. Main target of the work presented is to supply new approaches to stability investigations of wind turbines. The author's opinion is that an efficient, systematicstability analysis can not be performed for large...

  5. Distribution of chromium in vegetation and small mammals adjacent to cooling towers

    International Nuclear Information System (INIS)

    Taylor, F.G. Jr.; Parr, P.D.; Dahlman, R.C.

    1975-01-01

    Surface contamination of vegetation by aerosol pollutants and subsequent ingestion by grazing vertebrates is a pathway for incorporation of toxic elements into food chains. Small mammals (herbivores) were live-trapped in a fescue-dominated field adjacent to large, mechanical draft cooling towers comparable to those utilized by power generation facilities. Cooling waters of the towers contain a chromate, zinc-phosphate compound to inhibit corrosion and fouling within the cooling system. A fraction of the cooling water becomes entrained within the exit air flow and is deposited as drift on the landscape. Resident mammals are chronically subjected to increased chromium exposures through both ingestion and inhalation pathways. Concentrations in vegetation ranged from 342 to 15 ppM at 15 and 130 meters down wind. Concentration levels in litter exceeded those of live plant materials by a factor of 5. Chromium distribution in mammals adjacent to the cooling towers is compared by organ analyses to corresponding organs and tissues of mammals collected remote from drift. Concentrations of chromium in pelt, hair, and bone of animals trapped near the cooling towers were significantly higher (P is less than 0.01) than tissues from control animals. Air concentrations ranged from 15 to 8 μg/m 3 at 15 and 100 meters, and thus provided a potential pathway for increased chromium levels through inhalation. Biological accumulation and retention following ingestion are discussed in a subsequent paper in this symposium (Van Hook et al.). Elevated levels of hexavalent chromium in air have been identified as a potential health hazard. Pathological studies of lung tissues were performed and were negative for lesions. (U.S.)

  6. Mathematical model of drift deposition from a bifurcated cooling tower plume

    International Nuclear Information System (INIS)

    Chen, N.C.J.; Jung, L.

    1978-01-01

    Cooling tower drift deposition modeling has been extended by including centrifugal force induced through plume bifurcation in a crosswind as a mechanism for drift droplet removal from the plume. The model, in its current state of development, is capable of predicting the trajectory of a single droplet from the stage of strong interaction with the vortex field soon after droplet emission at the tower top through the stage of droplet evaporation in an unsaturated atmosphere after droplet breakaway from the plume. The computer program developed from the mathematical formulation has been used to explore the dependency of the droplet trajectory on droplet size, vortex strength, point of droplet emission, drag coefficient, droplet efflux speed, and ambient conditions. A specific application to drift from a mechanical-draft cooling tower (for a wind speed twice the efflux speed, a relative humidity of 70 per cent, and an initial droplet radius of 100 μm) showed the droplet to follow a helical trajectory within the plume, with breakaway occurring at 2.5 tower diameters downwind and ground impact of the droplet (reduced through evaporation to 55 μm radius) at 11 tower diameters

  7. Noise emissions of cooling towers; Geraeuschemissionen von Kuehltuermen

    Energy Technology Data Exchange (ETDEWEB)

    Hinkelmann, Dirk [Mueller-BBM GmbH, Gelsenkirchen (Germany)

    2013-09-01

    Cooling towers are often large structures with high sound emission. The impact of water drops on the water surface in the collecting basin leads to the generation of middle- and high-frequency noise that is emitted via the air intake opening and the outlet. In forced-draft cooling towers, additional noise is generated by drives and fans. The sound emissions can be predicted by means of empirical calculation models. In this way, noise control measures can be taken into account already at an early phase of planning. Different, proven measures for reduction of sound emissions are taken depending on cooling tower design. Regulations on noise acceptance testing for cooling towers are given in various standards. (orig.)

  8. Trade winds turn on the lights - wind home systems in action

    International Nuclear Information System (INIS)

    Kruse, A.

    1998-01-01

    This article reports on the use of a micro wind turbine designed for domestic use in a house in the Enriquillo village in the Dominican Republic which is in the path of the trade winds. The use of wind home systems for rural electrification, installation of similar systems in the north of the country following the success of the Enriquillo system, the shipping of the windpower kits minus the towers which are to be built locally, and the micro-financing of the project are discussed

  9. A Practical Application Combining Wireless Sensor Networks and Internet of Things: Safety Management System for Tower Crane Groups

    Directory of Open Access Journals (Sweden)

    Dexing Zhong

    2014-07-01

    Full Text Available The so-called Internet of Things (IoT has attracted increasing attention in the field of computer and information science. In this paper, a specific application of IoT, named Safety Management System for Tower Crane Groups (SMS-TC, is proposed for use in the construction industry field. The operating status of each tower crane was detected by a set of customized sensors, including horizontal and vertical position sensors for the trolley, angle sensors for the jib and load, tilt and wind speed sensors for the tower body. The sensor data is collected and processed by the Tower Crane Safety Terminal Equipment (TC-STE installed in the driver’s operating room. Wireless communication between each TC-STE and the Local Monitoring Terminal (LMT at the ground worksite were fulfilled through a Zigbee wireless network. LMT can share the status information of the whole group with each TC-STE, while the LMT records the real-time data and reports it to the Remote Supervision Platform (RSP through General Packet Radio Service (GPRS. Based on the global status data of the whole group, an anti-collision algorithm was executed in each TC-STE to ensure the safety of each tower crane during construction. Remote supervision can be fulfilled using our client software installed on a personal computer (PC or smartphone. SMS-TC could be considered as a promising practical application that combines a Wireless Sensor Network with the Internet of Things.

  10. A Practical Application Combining Wireless Sensor Networks and Internet of Things: Safety Management System for Tower Crane Groups

    Science.gov (United States)

    Zhong, Dexing; Lv, Hongqiang; Han, Jiuqiang; Wei, Quanrui

    2014-01-01

    The so-called Internet of Things (IoT) has attracted increasing attention in the field of computer and information science. In this paper, a specific application of IoT, named Safety Management System for Tower Crane Groups (SMS-TC), is proposed for use in the construction industry field. The operating status of each tower crane was detected by a set of customized sensors, including horizontal and vertical position sensors for the trolley, angle sensors for the jib and load, tilt and wind speed sensors for the tower body. The sensor data is collected and processed by the Tower Crane Safety Terminal Equipment (TC-STE) installed in the driver's operating room. Wireless communication between each TC-STE and the Local Monitoring Terminal (LMT) at the ground worksite were fulfilled through a Zigbee wireless network. LMT can share the status information of the whole group with each TC-STE, while the LMT records the real-time data and reports it to the Remote Supervision Platform (RSP) through General Packet Radio Service (GPRS). Based on the global status data of the whole group, an anti-collision algorithm was executed in each TC-STE to ensure the safety of each tower crane during construction. Remote supervision can be fulfilled using our client software installed on a personal computer (PC) or smartphone. SMS-TC could be considered as a promising practical application that combines a Wireless Sensor Network with the Internet of Things. PMID:25196106

  11. A practical application combining wireless sensor networks and Internet of Things: Safety Management System for Tower Crane Groups.

    Science.gov (United States)

    Zhong, Dexing; Lv, Hongqiang; Han, Jiuqiang; Wei, Quanrui

    2014-07-30

    The so-called Internet of Things (IoT) has attracted increasing attention in the field of computer and information science. In this paper, a specific application of IoT, named Safety Management System for Tower Crane Groups (SMS-TC), is proposed for use in the construction industry field. The operating status of each tower crane was detected by a set of customized sensors, including horizontal and vertical position sensors for the trolley, angle sensors for the jib and load, tilt and wind speed sensors for the tower body. The sensor data is collected and processed by the Tower Crane Safety Terminal Equipment (TC-STE) installed in the driver's operating room. Wireless communication between each TC-STE and the Local Monitoring Terminal (LMT) at the ground worksite were fulfilled through a Zigbee wireless network. LMT can share the status information of the whole group with each TC-STE, while the LMT records the real-time data and reports it to the Remote Supervision Platform (RSP) through General Packet Radio Service (GPRS). Based on the global status data of the whole group, an anti-collision algorithm was executed in each TC-STE to ensure the safety of each tower crane during construction. Remote supervision can be fulfilled using our client software installed on a personal computer (PC) or smartphone. SMS-TC could be considered as a promising practical application that combines a Wireless Sensor Network with the Internet of Things.

  12. 2D study of wind forces around multiple cooling towers using ...

    African Journals Online (AJOL)

    user

    above, a pure numerical study were done on three and five cooling towers (in ... Invent of high speed digital computer technology had enabled the solution of flow ... The purpose of this work was to present a new design method, which ...

  13. Simulation of a 5MW wind turbine in an atmospheric boundary layer

    International Nuclear Information System (INIS)

    Meister, Konrad; Lutz, Thorsten; Krämer, Ewald

    2014-01-01

    This article presents detached eddy simulation (DES) results of a 5MW wind turbine in an unsteady atmospheric boundary layer. The evaluation performed in this article focuses on turbine blade loads as well as on the influence of atmospheric turbulence and tower on blade loads. Therefore, the turbulence transport of the atmospheric boundary layer to the turbine position is analyzed. To determine the influence of atmospheric turbulence on wind turbines the blade load spectrum is evaluated and compared to wind turbine simulation results with uniform inflow. Moreover, the influences of different frequency regimes and the tower on the blade loads are discussed. Finally, the normal force coefficient spectrum is analyzed at three different radial positions and the influence of tower and atmospheric turbulence is shown

  14. Wind speed and direction shears with associated vertical motion during strong surface winds

    Science.gov (United States)

    Alexander, M. B.; Camp, D. W.

    1984-01-01

    Strong surface winds recorded at the NASA 150-Meter Ground Winds Tower facility at Kennedy Space Center, Florida, are analyzed to present occurrences representative of wind shear and vertical motion known to be hazardous to the ascent and descent of conventional aircraft and the Space Shuttle. Graphical (percentage frequency distributions) and mathematical (maximum, mean, standard deviation) descriptions of wind speed and direction shears and associated updrafts and downdrafts are included as functions of six vertical layers and one horizontal distance for twenty 5-second intervals of parameters sampled simultaneously at the rate of ten per second during a period of high surface winds.

  15. Observed rise of visible plumes from hyperbolic natural draft cooling towers

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, P T [Smith-Singer Meteorologists, Inc., Amityville, NY; Seymour, D E; Butler, M J; Kramer, M L; Smith, M E; Frankenberg, T T

    1976-01-01

    The behavior of natural draft cooling tower plumes and related meteorological variables have been measured from aircraft near three major plants of the American Electric Power System. The rise of those plumes which persisted long enough to reach a stabilized height depended primarily upon the height of the capping inversion aloft. All such plumes rose to elevations of 425 m or more above grade. No significant relationships between plume rise and wind speed, plant load, or ambient temperature were found. We conclude that simple temperature humidity soundings in the vicinity of the towers would serve as effective predictors of plume rise and persistence.

  16. Mitigation of Power System Oscillation Caused by Wind Power Fluctuation

    DEFF Research Database (Denmark)

    Su, Chi; Hu, Weihao; Chen, Zhe

    2013-01-01

    oscillation mitigation controllers are proposed and compared. A model of direct-drive-full-convertor-based wind farm connected to the IEEE 10-machine 39-bus system is adopted as the test system. The calculations and simulations are conducted in DIgSILENT PowerFactory 14.0. Results are presented to show......Wind power is increasingly integrated in modern power grids, which brings new challenges to the power system operation. Wind power is fluctuating because of the uncertain nature of wind, whereas wind shear and tower shadow effects also cause periodic fluctuations. These may lead to serious forced...... oscillation when the frequencies of the periodic fluctuations are close to the natural oscillation frequencies of the connected power system. By using modal analysis and time-domain simulations, this study studies the forced oscillation caused by the wind shear and tower shadow effects. Three forced...

  17. Analysis of extreme wind events at Høvsøre and the effect on wind turbine loads

    DEFF Research Database (Denmark)

    Hannesdóttir, Ásta; Kelly, Mark C.; Mann, Jakob

    used to simulate wind turbine response in time domain. The simulations are made for the DTU 10 MW reference wind turbine. Load analysis shows that the maximum tilt moment on the tower yaw bearing correlates well with the wind shear of the measurements. When these loads are compared with the extreme...... wind shear load case of the IEC standards, it is seen that they are of similar magnitude and in one case even higher....

  18. Wind Development on Tribal Lands

    Energy Technology Data Exchange (ETDEWEB)

    Ken Haukaas; Dale Osborn; Belvin Pete

    2008-01-18

    Background: The Rosebud Sioux Tribe (RST) is located in south central South Dakota near the Nebraska border. The nearest community of size is Valentine, Nebraska. The RST is a recipient of several Department of Energy grants, written by Distributed Generation Systems, Inc. (Disgen), for the purposes of assessing the feasibility of its wind resource and subsequently to fund the development of the project. Disgen, as the contracting entity to the RST for this project, has completed all the pre-construction activities, with the exception of the power purchase agreement and interconnection agreement, to commence financing and construction of the project. The focus of this financing is to maximize the economic benefits to the RST while achieving commercially reasonable rates of return and fees for the other parties involved. Each of the development activities required and its status is discussed below. Land Resource: The Owl Feather War Bonnet 30 MW Wind Project is located on RST Tribal Trust Land of approximately 680 acres adjacent to the community of St. Francis, South Dakota. The RST Tribal Council has voted on several occasions for the development of this land for wind energy purposes, as has the District of St. Francis. Actual footprint of wind farm will be approx. 50 acres. Wind Resource Assessment: The wind data has been collected from the site since May 1, 2001 and continues to be collected and analyzed. The latest projections indicate a net capacity factor of 42% at a hub height of 80 meters. The data has been collected utilizing an NRG 9300 Data logger System with instrumentation installed at 30, 40 and 65 meters on an existing KINI radio tower. The long-term annual average wind speed at 65-meters above ground level is 18.2 mph (8.1 mps) and 18.7 mph (8.4 mps) at 80-meters agl. The wind resource is excellent and supports project financing.

  19. Experimental Investigation on Strengthening of Bolted Connections in Transmission/Communication Towers

    Science.gov (United States)

    Balagopal, R.; Prasad Rao, N.; Rokade, R. P.; Umesha, P. K.

    2018-02-01

    Due to increase in demand for power supply and increase in bandwidth for communication industry, the existing transmission line (TL) and communication towers needs to be strengthened. The strengthening of existing tower is economical rather than installation of new towers due to constraints in acquisition of land. The size of conductors have to be increased or additional number of antenna needs to be installed in existing TL/communication tower respectively. The compression and tension capacity of members in the existing towers have to be increased to sustain the additional loads due to wind and self-weight of these components. The tension capacity enhancement of existing angle sections in live line condition without power shut-down is a challenging task. In the present study, the use of Glass Fiber Reinforced Plastic (GFRP) plate/angle sections is explored to strengthen existing bolted connections in TL/communication towers. Experimental investigation conducted at component level on strengthening of existing two types of single cover steel butt joint, one made of steel plate and another joint made of steel angle sections respectively. First series of experiment conducted on strengthening the connection using GFRP plate/cleat angle sections. The second series of strengthening experiment is conducted using steel plate/angle sections to replace GFRP sections. The load sharing behaviour of strengthened GFRP and steel section is compared and suitable recommendations are given.

  20. Experimental Investigation on Strengthening of Bolted Connections in Transmission/Communication Towers

    Science.gov (United States)

    Balagopal, R.; Prasad Rao, N.; Rokade, R. P.; Umesha, P. K.

    2018-06-01

    Due to increase in demand for power supply and increase in bandwidth for communication industry, the existing transmission line (TL) and communication towers needs to be strengthened. The strengthening of existing tower is economical rather than installation of new towers due to constraints in acquisition of land. The size of conductors have to be increased or additional number of antenna needs to be installed in existing TL/communication tower respectively. The compression and tension capacity of members in the existing towers have to be increased to sustain the additional loads due to wind and self-weight of these components. The tension capacity enhancement of existing angle sections in live line condition without power shut-down is a challenging task. In the present study, the use of Glass Fiber Reinforced Plastic (GFRP) plate/angle sections is explored to strengthen existing bolted connections in TL/communication towers. Experimental investigation conducted at component level on strengthening of existing two types of single cover steel butt joint, one made of steel plate and another joint made of steel angle sections respectively. First series of experiment conducted on strengthening the connection using GFRP plate/cleat angle sections. The second series of strengthening experiment is conducted using steel plate/angle sections to replace GFRP sections. The load sharing behaviour of strengthened GFRP and steel section is compared and suitable recommendations are given.

  1. Determination of the replacement cooling tower capability at the ETRR-2 research reactor

    International Nuclear Information System (INIS)

    El-Din El-Morshdy, S.

    2004-01-01

    The ETRR-2 replacement cooling tower capability has been evaluated by the thermal acceptance test performed in June 2003. All instruments used were calibrated prior to the test. The measured data are collected at regular intervals in accordance with the acceptance test code for water cooling towers of the cooling tower institute recommendations. Both the characteristic curve and the performance curve methods were used to evaluate the tower capability. The test results yield a tower capability of about 105% and so the tower is thermally accepted. (orig.)

  2. Application of two passive strategies on the load mitigation of large offshore wind turbines

    Science.gov (United States)

    Shirzadeh, Rasoul; Kühn, Martin

    2016-09-01

    This study presents the numerical results of two passive strategies to reduce the support structure loads of a large offshore wind turbine. In the first approach, an omnidirectional tuned mass damper is designed and implemented in the tower top to alleviate the structural vibrations. In the second approach, a viscous fluid damper model which is diagonally attached to the tower at two points is developed. Aeroelastic simulations are performed for the offshore 10MW INNWIND.EU reference wind turbine mounted on a jacket structure. Lifetime damage equivalent loads are evaluated at the tower base and compared with those for the reference wind turbine. The results show that the integrated design can extend the lifetime of the support structure.

  3. Experimental and Numerical Vibrational Analysis of a Horizontal-Axis Micro-Wind Turbine

    Directory of Open Access Journals (Sweden)

    Francesco Castellani

    2018-02-01

    Full Text Available Micro-wind turbines are energy conversion technologies strongly affected by fatigue, as a result of their size and the variability of loads, induced by the unsteady wind conditions, and modulated by a very high rotational speed. This work is devoted to the experimental and numerical characterization of the aeroelastic behavior of a test-case horizontal-axis wind turbine (HAWT with a 2 m rotor diameter and a maximum power production of 3 kW. The experimental studies have been conducted at the wind tunnel of the University of Perugia and consisted of accelerometer measurements at the tower and the tail fin. The numerical setup was the Fatigue, Aerodynamics, Structures, and Turbulence (FAST code for aeroelastic simulations, which was fed as input with the same wind conditions employed in the wind tunnel tests. The experimental and numerical analyses were coupled with the perspective of establishing a reciprocal feedback, and this has been accomplished. On one hand, the numerical model is important for interpreting the measured spectrum of tower oscillations and, for example, inspires the detection of a mass unbalance at the blades. On the other hand, the measurements inspire the question of how to interpret the interaction between the blades and the tower. The experimental spectrum of tail fin vibrations indicates that secondary elements, in terms of weight, can also transmit to the tower, giving meaningful contributions to the vibration spectra. Therefore, an integrated numerical and experimental approach is not only valuable but is also unavoidable, to fully characterize the dynamics of small wind-energy conversion systems.

  4. Cooling tower and environment

    International Nuclear Information System (INIS)

    Becker, J.; Ederhof, A.; Gosdowski, J.; Harms, A.; Ide, G.; Klotz, B.; Kowalczyk, R.; Necker, P.; Tesche, W.

    The influence of a cooling tower on the environment, or rather the influence of the environment on the cooling tower stands presently -along with the cooling water supply - in the middle of much discussion. The literature on these questions can hardly be overlooked by the experts concerned, especially not by the power station designers and operators. The document 'Cooling Tower and Environment' is intented to give a general idea of the important publications in this field, and to inform of the present state of technology. In this, the explanations on every section make it easier to get to know the specific subject area. In addition to older standard literature, this publication contains the best-known literature of recent years up to spring 1975, including some articles written in English. Further English literature has been collected by the ZAED (KFK) and is available at the VGB-Geschaefsstelle. Furthermore, The Bundesumweltamt compiles the literature on the subject of 'Environmental protection'. On top of that, further documentation centres are listed at the end of this text. (orig.) [de

  5. Fourier Simulation of a Non-Isotropic Wind Field Model

    DEFF Research Database (Denmark)

    Mann, J.; Krenk, S.

    Realistic modelling of three dimensional wind fields has become important in calculation of dynamic loads on same spatially extended structures, such as large bridges, towers and wind turbines. For some structures the along wind component of the of the turbulent flow is important while for others...

  6. The Transmission Channel Tower Identification and Landslide Disaster Monitoring Based on Insar

    Science.gov (United States)

    Li, G.; Tan, Q.; Xie, C.; Fei, X.; Ma, X.; Zhao, B.; Ou, W.; Yang, Z.; Wang, J.; Fang, H.

    2018-04-01

    The transmission distance of transmission lines is long, the line affected by the diversity of climate and topography of the corridors of transmission lines, differences in regional geological structure conditions, variability of rock and soil types, and the complexity of groundwater. Under the influence of extreme weather conditions (ice-covered, strong wind, etc.) and sudden geological disasters (such as mudslides, flash floods, earthquakes, etc.), catastrophic damage and basic deformation problems of the tower foundations are prone, and even tower collapse accidents occur in severe cases, which affect the safe operation of transmission lines. Monitoring the deformation of power transmission towers and surrounding grounds, it is critical to ensuring the normal operation of transmission lines by assessing and controlling potential risks in advance. In this paper, using ALOS-2 PALSAR radar satellite data, differential interferometry was used to monitor surface deformation near the Sichuan Jinsu line transmission channel. The analysis found that a significant landslide hazard was found near the transmission channel tower in Yibin-Zhaotong section of Jinsu, Sichuan Province, the cumulative deformation reaches 9cm. The results of this paper can provide new monitoring means for safety monitoring of transmission towers.

  7. Unsteady aerodynamics simulation of a full-scale horizontal axis wind turbine using CFD methodology

    International Nuclear Information System (INIS)

    Cai, Xin; Gu, Rongrong; Pan, Pan; Zhu, Jie

    2016-01-01

    Highlights: • A full-scale HAWT is simulated under operational conditions of wind shear and yaw. • The CFD method and sliding mesh are adopted to complete the calculation. • Thrust and torque of blades reach the peak and valley at the same time in wind shear. • The wind turbine produces yaw moment during the whole revolution in yaw case. • The torques and thrusts of the three blades present cyclical changes. - Abstract: The aerodynamic performance of wind turbines is significantly influenced by the unsteady flow around the rotor blades. The research on unsteady aerodynamics for Horizontal Axis Wind Turbines (HAWTs) is still poorly understood because of the complex flow physics. In this study, the unsteady aerodynamic configuration of a full-scale HAWT is simulated with consideration of wind shear, tower shadow and yaw motion. The calculated wind turbine which contains tapered tower, rotor overhang and tilted rotor shaft is constructed by making reference of successfully commercial operated wind turbine designed by NEG Micon and Vestas. A validated CFD method is utilized to analyze unsteady aerodynamic characteristics which affect the performance on such a full-scale HAWT. The approach of sliding mesh is used to carefully deal with the interface between static and moving parts in the flow field. The annual average wind velocity and wind profile in the atmospheric border are applied as boundary conditions. Considering the effects of wind shear and tower shadow, the simulation results show that the each blade reaches its maximum and minimum aerodynamic loads almost at the same time during the rotation circle. The blade–tower interaction imposes great impact on the power output performance. The wind turbine produces yaw moment during the whole revolution and the maximum aerodynamic loads appear at the upwind azimuth in the yaw computation case.

  8. The nature of wind turbine fatigue loads in wind farms

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Larsen, Torben J.; Aagaard Madsen, Helge

    2013-01-01

    The aim of the present paper is to further validate the predictive capability of the DWM/HAWC2 package for simulation of structural loadings in wind farms. The validation in particular focus on tower fatigue loading characteristics (i.e. equivalent moments) as function of turbine relative positio...

  9. Electrical Collection and Transmission Systems for Offshore Wind Power: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.; Bowen, A.; Fingersh, L.J.; Wan, Y.

    2007-03-01

    The electrical systems needed for offshore wind farms to collect power from wind turbines--and transmit it to shore--will be a significant cost element of these systems. This paper describes the development of a simplified model of the cost and performance of such systems.

  10. Study on Remote Monitoring System of Crossing and Spanning Tangent Tower

    Science.gov (United States)

    Chen, Da-bing; Zhang, Nai-long; Zhang, Meng-ge; Wang, Ze-hua; Zhang, Yan

    2017-05-01

    In order to grasp the vibration state of overhead transmission line and ensure the operational security of transmission line, the remote monitoring system of crossing and spanning tangent tower was studied. By use of this system, the displacement, velocity and acceleration of the tower, and the local weather data are collected automatically, displayed on computer of remote monitoring centre through wireless network, real-time collection and transmission of vibration signals are realized. The applying results show that the system is excellent in reliability and accuracy and so on. The system can be used to remote monitoring of transmission tower of UHV power transmission lines and in large spanning areas.

  11. Natural-draught cooling towers made of reinforced concrete. State of the art and development possibilities

    Energy Technology Data Exchange (ETDEWEB)

    Kraetzig, W B; Peters, H L; Zerna, W

    1978-03-01

    Large power plant units and dry cooling tower technology require larger dimensions for natural-draught cooling towers. The main curvation radii in latitudinal and meridian direction are thus increased, which results in a lower three-dimensional support strength. This development is an incentive for constant re-consideration of calculation methods, safety philosophy, and dimensioning criteria. In this context, wind effects have been re-formulated and given a scientific foundation. Constructional measures to improve the static and dynamic behaviour of the structure have been presented and critically assessed. A cost analysis, finally, gave the most rational applications of the new shell construction with reinforcing elements. A cooling tower now under construction gave a realistic example. Fundamental aspects concerning the foundations of cooling tower shells and two special types of foundation are further points to clarify the subject.

  12. Edgewise vibration control of wind turbine blades using roller and liquid dampers

    International Nuclear Information System (INIS)

    Zhang, Z L; Nielsen, S R K

    2014-01-01

    This paper deals with the passive vibration control of edgewise vibrations by means of roller dampers and tuned liquid column dampers (TLCDs). For a rotating blade, the large centrifugal acceleration makes it possible to use roller dampers or TLCDs with rather small masses for effectively suppressing edgewise vibrations. The roller dampers are more volumetrically efficient due to the higher mass density of the steel comparing with the liquid. On the other hand, TLCDs have their advantage that it is easier to specify the optimum damping of the damper by changing the opening ratio of the orifice. In this paper, 2-DOF nonlinear models are suggested for tuning a roller damper or a TLCD attached to a rotating wind turbine blade, ignoring the coupling between the blade and the tower. The decoupled optimization is verified by incorporating the optimized damper into a more sophisticated 13- DOF wind turbine model with due consideration of the coupled blade-tower-drivetrain vibrations, quasi-static aeroelasticity as well as a collective pitch controller. Performances of the dampers are compared in terms of the control efficiency and the practical applications. The results indicate that roller dampers and TLCDs at optimal tuning can effectively suppress the dynamic response of wind turbine blades

  13. Super-long bridges with floating towers: the role of multi-box decks and Hardware-In-the-Loop technology for wind tunnel tests

    Science.gov (United States)

    Zasso, A.; Argentini, T.; Bayati, I.; Belloli, M.; Rocchi, D.

    2017-12-01

    The super long fjord crossings in E39 Norwegian project pose new challenges to long span bridge design and construction technology. Proposed solutions should consider the adoption of bridge deck with super long spans or floating solutions for at least one of the towers, due to the relevant fjord depth. At the same time, the exposed fjord environment, possibly facing the open ocean, calls for higher aerodynamic stability performances. In relation to this scenario, the present paper addresses two topics: 1) the aerodynamic advantages of multi-box deck sections in terms of aeroelastic stability, and 2) an experimental setup in a wind tunnel able to simulate the aeroelastic bridge response including the wave forcing on the floating.

  14. Comparison of Microwave Backscatter Measurements and Small-scale Surface Wave Measurements Made from the Dutch Ocean Research Tower "Noordwijk"

    NARCIS (Netherlands)

    Snoeij, P.; Halsema, D. van; Oost, W.A.; Calkoen, C.J.; Vogelzang, J.; Waas, S.; Jaehne, B.

    1991-01-01

    To improve the understanding of the interaction between microwaves and water waves the VIERS-l project started in 1986 with the preparation of two wind/wave tank experiments and an ocean tower experiment. In February 1988, combined measurements of microwave backscatter, wind, waves and gas exchange

  15. Noise from wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

    2002-02-01

    A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

  16. A study on the possibility of cooling of schools by natural wind flow. Paper no. IGEC-1-146

    International Nuclear Information System (INIS)

    Setodemaram, K.; Golneshan, A.A.; Jafarpur, Kh.

    2005-01-01

    In this paper, the possibility of using 'wind' to cool (by wind tower) the air spaces in schools is studied. In order to study the effect of wind tower on natural cooling of schools, one has to determine the value of convective heat transfer coefficient in the classes. For this purpose, a 1:35 scale plexi glass model of a typical 8- classes school was made and a series of experiments were conducted in a wind tunnel. Mass transfer analogy using naphthalene sublimation was employed to measure the convective heat transfer coefficient in the model. It's worth mentioning that the plexi-model was equipped with a Baud-geer (wind tower) for studying of air into classes. After determining the convective heat transfer coefficient, effect of students and night ventilation on temperature variations in the classes was studied by computer simulation. (author)

  17. ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION

    International Nuclear Information System (INIS)

    Heber, Veronika S.; Baur, Heinrich; Wieler, Rainer; Bochsler, Peter; McKeegan, Kevin D.; Neugebauer, Marcia; Reisenfeld, Daniel B.; Wiens, Roger C.

    2012-01-01

    NASA's Genesis space mission returned samples of solar wind collected over ∼2.3 years. We present elemental and isotopic compositions of He, Ne, and Ar analyzed in diamond-like carbon targets from the slow and fast solar wind collectors to investigate isotopic fractionation processes during solar wind formation. The solar wind provides information on the isotopic composition for most volatile elements for the solar atmosphere, the bulk Sun and hence, on the solar nebula from which it formed 4.6 Ga ago. Our data reveal a heavy isotope depletion in the slow solar wind compared to the fast wind composition by 63.1 ± 2.1 per mille for He, 4.2 ± 0.5 per mille amu –1 for Ne and 2.6 ± 0.5 per mille amu –1 for Ar. The three Ne isotopes suggest that isotopic fractionation processes between fast and slow solar wind are mass dependent. The He/H ratios of the collected slow and fast solar wind samples are 0.0344 and 0.0406, respectively. The inefficient Coulomb drag model reproduces the measured isotopic fractionation between fast and slow wind. Therefore, we apply this model to infer the photospheric isotopic composition of He, Ne, and Ar from our solar wind data. We also compare the isotopic composition of oxygen and nitrogen measured in the solar wind with values of early solar system condensates, probably representing solar nebula composition. We interpret the differences between these samples as being due to isotopic fractionation during solar wind formation. For both elements, the magnitude and sign of the observed differences are in good agreement with the values predicted by the inefficient Coulomb drag model.

  18. ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Heber, Veronika S.; Baur, Heinrich; Wieler, Rainer [Institute for Geochemistry and Petrology, ETH Zurich, Clausiusstrasse 25, CH-8092 Zurich (Switzerland); Bochsler, Peter [Physikalisches Institut, Universitaet Bern, Sidlerstasse 5, CH-3012 Bern (Switzerland); McKeegan, Kevin D. [Department of Earth and Space Sciences, University of California Los Angeles, 595 Charles Young Drive East, Box 951567, Los Angeles, CA 90095-1567 (United States); Neugebauer, Marcia [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States); Reisenfeld, Daniel B. [Department of Physics and Astronomy, University of Montana, Missoula, MT 59812 (United States); Wiens, Roger C., E-mail: heber@ess.ucla.edu [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2012-11-10

    NASA's Genesis space mission returned samples of solar wind collected over {approx}2.3 years. We present elemental and isotopic compositions of He, Ne, and Ar analyzed in diamond-like carbon targets from the slow and fast solar wind collectors to investigate isotopic fractionation processes during solar wind formation. The solar wind provides information on the isotopic composition for most volatile elements for the solar atmosphere, the bulk Sun and hence, on the solar nebula from which it formed 4.6 Ga ago. Our data reveal a heavy isotope depletion in the slow solar wind compared to the fast wind composition by 63.1 {+-} 2.1 per mille for He, 4.2 {+-} 0.5 per mille amu{sup -1} for Ne and 2.6 {+-} 0.5 per mille amu{sup -1} for Ar. The three Ne isotopes suggest that isotopic fractionation processes between fast and slow solar wind are mass dependent. The He/H ratios of the collected slow and fast solar wind samples are 0.0344 and 0.0406, respectively. The inefficient Coulomb drag model reproduces the measured isotopic fractionation between fast and slow wind. Therefore, we apply this model to infer the photospheric isotopic composition of He, Ne, and Ar from our solar wind data. We also compare the isotopic composition of oxygen and nitrogen measured in the solar wind with values of early solar system condensates, probably representing solar nebula composition. We interpret the differences between these samples as being due to isotopic fractionation during solar wind formation. For both elements, the magnitude and sign of the observed differences are in good agreement with the values predicted by the inefficient Coulomb drag model.

  19. Optimal sensor placement for modal testing on wind turbines

    Science.gov (United States)

    Schulze, Andreas; Zierath, János; Rosenow, Sven-Erik; Bockhahn, Reik; Rachholz, Roman; Woernle, Christoph

    2016-09-01

    The mechanical design of wind turbines requires a profound understanding of the dynamic behaviour. Even though highly detailed simulation models are already in use to support wind turbine design, modal testing on a real prototype is irreplaceable to identify site-specific conditions such as the stiffness of the tower foundation. Correct identification of the mode shapes of a complex mechanical structure much depends on the placement of the sensors. For operational modal analysis of a 3 MW wind turbine with a 120 m rotor on a 100 m tower developed by W2E Wind to Energy, algorithms for optimal placement of acceleration sensors are applied. The mode shapes used for the optimisation are calculated by means of a detailed flexible multibody model of the wind turbine. Among the three algorithms in this study, the genetic algorithm with weighted off-diagonal criterion yields the sensor configuration with the highest quality. The ongoing measurements on the prototype will be the basis for the development of optimised wind turbine designs.

  20. A method of measuring and correcting tilt of anti - vibration wind turbines based on screening algorithm

    Science.gov (United States)

    Xiao, Zhongxiu

    2018-04-01

    A Method of Measuring and Correcting Tilt of Anti - vibration Wind Turbines Based on Screening Algorithm is proposed in this paper. First of all, we design a device which the core is the acceleration sensor ADXL203, the inclination is measured by installing it on the tower of the wind turbine as well as the engine room. Next using the Kalman filter algorithm to filter effectively by establishing a state space model for signal and noise. Then we use matlab for simulation. Considering the impact of the tower and nacelle vibration on the collected data, the original data and the filtering data are classified and stored by the Screening algorithm, then filter the filtering data to make the output data more accurate. Finally, we eliminate installation errors by using algorithm to achieve the tilt correction. The device based on this method has high precision, low cost and anti-vibration advantages. It has a wide range of application and promotion value.

  1. Isolation of Legionella pneumophila from hospital cooling towers in Johor, Malaysia.

    Science.gov (United States)

    Abdul Samad, B H; Suhaili, M R; Baba, N; Rajasekaran, G

    2004-08-01

    Water-based cooling towers and their water supply at two hospitals in Johor were surveyed for the presence Legionella pneumophila. L. pneumophila were grown from 19 (76%) out of 25 collected water samples. One hospital cooling tower was contaminated with L. pneumophila serogroup 1.

  2. Plankton data collected from instrumented tower and net casts in the Greenland Sea from the POLARSTERN from 09 June 1991 to 16 June 1991 (NODC Accession 0000772)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Plankton data were collected using instrumented tower and net casts from the POLARSTERN in the Greenland Sea. Data were collected from 09 June 1991 to 16 June 1991....

  3. Pre-feasibility study of 80mw onshore wind farm

    International Nuclear Information System (INIS)

    Almas, M.S.

    2014-01-01

    This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa) province previously known as NWFP (North West Frontier) Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology and Climatology (University of the Punjab) to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis) is presented and the feasibility of the project from the investor's point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years. (author)

  4. Aerodynamic flow simulation of wind turbine: Downwind versus upwind configuration

    International Nuclear Information System (INIS)

    Janajreh, Isam; Qudaih, Rana; Talab, Ilham; Ghenai, Chaouki

    2010-01-01

    Large scale wind turbines and wind farms continue to grow mounting 94.1 GW of the electrical grid capacity in 2007 and expected to reach 160.0 GW in 2010. Wind energy plays a vital role in the quest for renewable and sustainable energy as well as in reducing carbon emission. Early generation wind turbines (windmills) were used mainly for water pumping and seed grinding, whereas today they generate 1/5 of the current Denmark's electricity and will double its grid capacity reaching 12.5% in 2010. Wind energy is plentiful (72 TW estimated to be commercially viable) and clean while its intensive capital cost still impede widespread deployment. However, there are technological challenges, i.e. high fatigue load, noise emission, and meeting stringent reliability and safety standards. Newer inventions, e.g., downstream wind turbines and flapping rotor blades, are sought to enhance their performance, i.e. lower turning moments and cut-in speed and to absorb portion of the cost due to the absent of yaw mechanisms. In this work, numerical analysis of the downstream wind turbine blade is conducted. In particular, the interaction between the tower and the rotor passage is investigated. Circular cross sectional tower and aerofoil shapes are considered in a staggered configuration and under cross-stream motion. The resulting blade static pressure and aerodynamic forces are computed at different incident wind angles and wind speeds. The computed forces are compared to the conventional upstream wind turbine. Steady state and transient, incompressible, viscous Navier-Stokes and turbulent flow analysis are employed. The k-epsilon model is utilized as the turbulence closure. The passage of the rotor blade is governed by ALE and is represented numerically as a sliding mesh against the upstream fixed tower domain.

  5. Effects from fully nonlinear irregular wave forcing on the fatigue life of an offshore wind turbine and its monopile foundation

    DEFF Research Database (Denmark)

    Schløer, Signe; Bredmose, Henrik; Bingham, Harry B.

    2013-01-01

    The effect from fully nonlinear irregular wave forcing on the fatigue life of the foundation and tower of an offshore wind turbine is investigated through aeroelastic calculations. Five representative sea states with increasing significant wave height are considered in a water depth of 40 m....... The waves are both linear and fully nonlinear irregular 2D waves. The wind turbine is the NREL 5-MW reference wind turbine. Fatigue analysis is performed in relation to analysis of the sectional forces in the tower and monopile. Impulsive excitation of the sectional force at the bottom of the tower is seen...

  6. DC Collection Network Simulation for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Vogel, Stephan; Rasmussen, Tonny Wederberg; El-Khatib, Walid Ziad

    2015-01-01

    The possibility to connect offshore wind turbines with a collection network based on Direct Current (DC), instead of Alternating Current (AC), gained attention in the scientific and industrial environment. There are many promising properties of DC components that could be beneficial such as......: smaller dimensions, less weight, fewer conductors, no reactive power considerations, and less overall losses due to the absence of proximity and skin effects. This work describes a study about the simulation of a Medium Voltage DC (MVDC) grid in an offshore wind farm. Suitable converter concepts...

  7. Active tuned mass damper for damping of offshore wind turbine vibrations

    DEFF Research Database (Denmark)

    Brodersen, Mark Laier; Bjørke, Ann-Sofie; Høgsberg, Jan Becker

    2017-01-01

    An active tuned mass damper (ATMD) is employed for damping of tower vibrations of fixed offshore wind turbines, where the additional actuator force is controlled using feedback from the tower displacement and the relative velocity of the damper mass. An optimum tuning procedure equivalent to the ...

  8. Lidar observations of marine boundary-layer winds and heights: a preliminary study

    DEFF Research Database (Denmark)

    Peña, Alfredo; Gryning, Sven-Erik; Floors, Rogier Ralph

    2015-01-01

    the highest data availability (among the three sites) and a very good agreement with the observations of wind speed and direction from cup anemometers and vanes from the platform's tower. The wind lidar was also able to perform measurements under a winter storm where 10-s gusts were observed above 60 m s 1......Here we describe a nearly 1-yr meteorological campaign, which was carried out at the FINO3 marine research platform on the German North Sea, where a pulsed wind lidar and a ceilometer were installed besides the platform's 105-m tower and measured winds and the aerosol backscatter in the entire...... marine atmospheric boundary layer. The campaign was the last phase of a research project, in which the vertical wind profile in the atmospheric boundary layer was firstly investigated on a coastal and a semi-urban site. At FINO3 the wind lidar, which measures the wind speed up to 2000 m, shows...

  9. Laboratory Experiment and Numerical Analysis of a New Type of Solar Tower Efficiently Generating a Thermal Updraft

    Directory of Open Access Journals (Sweden)

    Yuji Ohya

    2016-12-01

    Full Text Available A new type of solar tower was developed through laboratory experiments and numerical analyses. The solar tower mainly consists of three components. The transparent collector area is an aboveground glass roof, with increasing height toward the center. Attached to the center of the inside of the collector is a vertical tower within which a wind turbine is mounted at the lower entry to the tower. When solar radiation heats the ground through the glass roof, ascending warm air is guided to the center and into the tower. A solar tower that can generate electricity using a simple structure that enables easy and less costly maintenance has considerable advantages. However, conversion efficiency from sunshine energy to mechanical turbine energy is very low. Aiming to improve this efficiency, the research project developed a diffuser-type tower instead of a cylindrical tower, and investigated a suitable diffuser shape for practical use. After changing the tower height and diffuser open angle, with a temperature difference between the ambient air aloft and within the collector, various diffuser tower shapes were tested by laboratory experiments and numerical analyses. As a result, it was found that a diffuser tower with a semi-open angle of 4° is an optimal shape, producing the fastest updraft at each temperature difference in both the laboratory experiments and numerical analyses. The relationships between thermal updraft speed and temperature difference and/or tower height were confirmed. It was found that the thermal updraft velocity is proportional to the square root of the tower height and/or temperature difference.

  10. Wind energy technology developments

    DEFF Research Database (Denmark)

    Madsen, Peter Hauge; Hansen, Morten Hartvig; Pedersen, Niels Leergaard

    2014-01-01

    turbine blades and towers are very large series-produced components, which costs and quality are strongly dependent on the manufacturing methods. The industrial wind energy sector is well developed in Denmark, and the competitive advantage of the Danish sector and the potential for job creation...

  11. The Quality Control Algorithms Used in the Creation of NASA Kennedy Space Center Lightning Protection System Towers Meteorological Database

    Science.gov (United States)

    Orcutt, John M.; Brenton, James C.

    2016-01-01

    An accurate database of meteorological data is essential for designing any aerospace vehicle and for preparing launch commit criteria. Meteorological instrumentation were recently placed on the three Lightning Protection System (LPS) towers at Kennedy Space Center (KSC) launch complex 39B (LC-39B), which provide a unique meteorological dataset existing at the launch complex over an extensive altitude range. Data records of temperature, dew point, relative humidity, wind speed, and wind direction are produced at 40, 78, 116, and 139 m at each tower. The Marshall Space Flight Center Natural Environments Branch (EV44) received an archive that consists of one-minute averaged measurements for the period of record of January 2011 - April 2015. However, before the received database could be used EV44 needed to remove any erroneous data from within the database through a comprehensive quality control (QC) process. The QC process applied to the LPS towers' meteorological data is similar to other QC processes developed by EV44, which were used in the creation of meteorological databases for other towers at KSC. The QC process utilized in this study has been modified specifically for use with the LPS tower database. The QC process first includes a check of each individual sensor. This check includes removing any unrealistic data and checking the temporal consistency of each variable. Next, data from all three sensors at each height are checked against each other, checked against climatology, and checked for sensors that erroneously report a constant value. Then, a vertical consistency check of each variable at each tower is completed. Last, the upwind sensor at each level is selected to minimize the influence of the towers and other structures at LC-39B on the measurements. The selection process for the upwind sensor implemented a study of tower-induced turbulence. This paper describes in detail the QC process, QC results, and the attributes of the LPS towers meteorological

  12. Design and Experimental Analysis of an Exhaust Air Energy Recovery Wind Turbine Generator

    Directory of Open Access Journals (Sweden)

    Ahmad Fazlizan

    2015-06-01

    Full Text Available A vertical axis wind turbine (VAWT was positioned at the discharge outlet of a cooling tower electricity generator. To avoid a negative impact on the performance of the cooling tower and to optimize the turbine performance, the determination of the VAWT position in the discharge wind stream was conducted by experiment. The preferable VAWT position is where the higher wind velocity matches the positive torque area of the turbine rotation. With the proper matching among the VAWT configurations (blade number, airfoil type, operating tip-speed-ratio, etc. and exhaust air profile, the turbine system was not only able to recover the wasted kinetic energy, it also reduced the fan motor power consumption by 4.5% and increased the cooling tower intake air flow-rate by 11%. The VAWT had a free running rotational speed of 479 rpm, power coefficient of 10.6%, and tip-speed-ratio of 1.88. The double multiple stream tube theory was used to explain the VAWT behavior in the non-uniform wind stream. For the actual size of a cooling tower with a 2.4 m outlet diameter and powered by a 7.5 kW fan motor, it was estimated that a system with two VAWTs (side-by-side can generate 1 kW of power which is equivalent to 13% of energy recovery.

  13. Legionella confirmation in cooling tower water

    Science.gov (United States)

    Farhat, Maha; Shaheed, Raja A.; Al-Ali, Haidar H.; Al-Ghamdi, Abdullah S.; Al-Hamaqi, Ghadeer M.; Maan, Hawraa S.; Al-Mahfoodh, Zainab A.; Al-Seba, Hussain Z.

    2018-01-01

    Objectives: To investigate the presence of Legionella spp in cooling tower water. Legionella proliferation in cooling tower water has serious public health implications as it can be transmitted to humans via aerosols and cause Legionnaires’ disease. Methods: Samples of cooling tower water were collected from King Fahd Hospital of the University (KFHU) (Imam Abdulrahman Bin Faisal University, 2015/2016). The water samples were analyzed by a standard Legionella culture method, real-time polymerase chain reaction (RT-PCR), and 16S rRNA next-generation sequencing. In addition, the bacterial community composition was evaluated. Results: All samples were negative by conventional Legionella culture. In contrast, all water samples yielded positive results by real-time PCR (105 to 106 GU/L). The results of 16S rRNA next generation sequencing showed high similarity and reproducibility among the water samples. The majority of sequences were Alpha-, Beta-, and Gamma-proteobacteria, and Legionella was the predominant genus. The hydrogen-oxidizing gram-negative bacterium Hydrogenophaga was present at high abundance, indicating high metabolic activity. Sphingopyxis, which is known for its resistance to antimicrobials and as a pioneer in biofilm formation, was also detected. Conclusion: Our findings indicate that monitoring of Legionella in cooling tower water would be enhanced by use of both conventional culturing and molecular methods. PMID:29436561

  14. Present state of the safety concept of natural-draught cooling towers

    International Nuclear Information System (INIS)

    Kraetzig, W.B.

    1977-01-01

    Safety and reliability of a building depend on the mechanical model chosen, on the shape deviations of the structure, as well as on the distribution functions and fractile values of the main influences and strength properties of the materials. For the shell, the supports, and the foundation of a natural-draught cooling tower, the wind plays a special, safety-reducing role due to the fact that its upper limit remains unknown. This role is still enhanced by the dead weight of the concrete which partially exceeds the tensile load. This requires a dimensioning concept with partial safety coefficients which is established in the present paper. So far, it has been successfully used in the construction of more than 50 cooling towers. (orig.) [de

  15. Studies for Characterisation of Electrical Properties of DC Collection System in Offshore Wind Farms

    DEFF Research Database (Denmark)

    Chen, Yu-Hsing; Dincan, Catalin Gabriel; Olsen, Rolant Joannesarson

    2016-01-01

    Offshore HVDC-connected wind farms where the wind plant power collection network becomes DC, rather than AC, offer reduced electrical losses, lower equipment ratings potentially leading to lower bill-of-material cost, and undiminished functionality. However, no standards exist for an offshore...... medium-voltage DC power collection cable-based system, routing power from MVDC wind turbines all the way to the HVDC export cable. To progress, it is therefore important to establish some common reference for the design and performance of the components needed in an MVDC collection network. Any suggested...... of the MVDC power collection, regardless of choice of turbine converter circuit, MVDC cable configuration, use of DC circuit breakers, substation converter circuit, control and protection. The paper presents the necessary list of studies, and includes examples of simulation results for an exemplary MVDC wind...

  16. Background and system description of the Mod 1 wind turbine generator

    Science.gov (United States)

    Ernst, E. H.

    1978-01-01

    The Mod-1 wind turbine considered is a large utility-class machine, operating in the high wind regime, which has the potential for generation of utility grade power at costs competitive with other alternative energy sources. A Mod-1 wind turbine generator (WTG) description is presented, taking into account the two variable-pitch steel blades of the rotor, the drive train, power generation/control, the Nacelle structure, and the yaw drive. The major surface elements of the WTG are the ground enclosure, the back-up battery system, the step-up transformer, elements of the data system, cabling, area lighting, and tower foundation. The final system weight (rotor, Nacelle, and tower) is expected to be about 650,000 pounds. The WTG will be capable of delivering 1800 kW to the utility grid in a wind-speed above 25 mph.

  17. Aerodynamic loads calculation and analysis for large scale wind turbine based on combining BEM modified theory with dynamic stall model

    Energy Technology Data Exchange (ETDEWEB)

    Dai, J.C. [College of Mechanical and Electrical Engineering, Central South University, Changsha (China); School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Hu, Y.P.; Liu, D.S. [School of Electromechanical Engineering, Hunan University of Science and Technology, Xiangtan (China); Long, X. [Hara XEMC Windpower Co., Ltd., Xiangtan (China)

    2011-03-15

    The aerodynamic loads for MW scale horizontal-axis wind turbines are calculated and analyzed in the established coordinate systems which are used to describe the wind turbine. In this paper, the blade element momentum (BEM) theory is employed and some corrections, such as Prandtl and Buhl models, are carried out. Based on the B-L semi-empirical dynamic stall (DS) model, a new modified DS model for NACA63-4xx airfoil is adopted. Then, by combing BEM modified theory with DS model, a set of calculation method of aerodynamic loads for large scale wind turbines is proposed, in which some influence factors such as wind shear, tower, tower and blade vibration are considered. The research results show that the presented dynamic stall model is good enough for engineering purpose; the aerodynamic loads are influenced by many factors such as tower shadow, wind shear, dynamic stall, tower and blade vibration, etc, with different degree; the single blade endures periodical changing loads but the variations of the rotor shaft power caused by the total aerodynamic torque in edgewise direction are very small. The presented study approach of aerodynamic loads calculation and analysis is of the university, and helpful for thorough research of loads reduction on large scale wind turbines. (author)

  18. Pre-Feasibility Study of 80MW Onshore Wind Farm

    Directory of Open Access Journals (Sweden)

    Muhammad Shoaib Almas

    2014-10-01

    Full Text Available This paper discusses a pre-feasibility study of 80MW onshore wind farm in the KPK (Khyber Pakhtunkhwa province previously known as NWFP (North West Frontier Province of Pakistan. The realistic data of wind speed is collected from Laboratory of Meteorology & Climatology (University of the Punjab to study the feasibility of wind farm. Detailed analysis of wind turbines from four different manufacturers is carried out together with justifications of selecting a particular wind turbine. Issues related to site selection, wind farm civil foundation, recommendations for a particular choice of tower along with environmental effects are presented. Wind data analysis is carried out by using WINDROSE PRO software to determine the resultant direction of wind at the selected site for wind farm layout. The wind distribution at hub height of the wind turbine is calculated and is used to compute annual power production by the wind farm using power curves of the wind turbine. Electrical network integration issues of wind farm to the external grid are studied and the optimum point of connection is proposed. Finally, economic analysis of the whole wind farm project depending upon the LCC (Life Cycle Cost Analysis is presented and the feasibility of the project from the investor?s point of view is identified. The study concludes that the cost per kilowatt hour of electricity generated by this wind power plant will be 10.4 PKR/kWh and the payback period for the whole project is about 11.2 years

  19. Wind turbine/generator set having a stator cooling system located between stator frame and active coils

    Science.gov (United States)

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2012-11-13

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  20. Effects of nearby surface features on wind speed at a nuclear plant meteorological station

    International Nuclear Information System (INIS)

    Nielsen, N.A.; Goodwin, R.J.; Pittman, D.E.

    1984-01-01

    There is a definite cause and effect relationship between the trees in the vicinity of the meteorological tower and the wind speed at the 10-meter level on the meteorological tower. For the affected directions, horizontal wind speed is significantly reduced below what it would be for that level if the trees were not present. This effect is only slightly less for the 10:1 exposure achieved with the 1977 tree clearing, which illustrates that meeting this commonly accepted distance to height ratio does not assure representativeness of 10-meter data collected at a nuclear plant site. The somewhat stronger effect for winds from the south through southwest directions may be partly attributable to the abrupt change in roughness and elevation encountered by air moving at an angle or directly across the reservoir, which is 3.5 to 5.0 kilometers wide at this site. This general reduction in wind speed values below what would be expected at the plant location will result in biased dispersion estimates. Calculated relative concentration values for releases treated as ground-level or building-wake releases would be larger than actual concentrations. While this would provide conservative concentration values, radioactive plume transport calculations would be nonconservative. The calculated, or predicted, transport rate would be slower than the actual transport rate. Such local biases affecting the spatial representativeness of airflow at 10 meters are a primary reason for TVA's decision to use 46-meter wind data for ground-level transport and diffusion modeling in its radiological emergency preparedness program

  1. Effects of torsional degree of freedom, geometric nonlinearity, and gravity on aeroelastic behavior of large-scale horizontal axis wind turbine blades under varying wind speed conditions

    DEFF Research Database (Denmark)

    Jeong, Min-Soo; Cha, Myung-Chan; Kim, Sang-Woo

    2014-01-01

    Modern horizontal axis wind turbine blades are long, slender, and flexible structures that can undergo considerable deformation, leading to blade failures (e.g., blade-tower collision). For this reason, it is important to estimate blade behaviors accurately when designing large-scale wind turbine...

  2. Study of blade-tower interaction using a 2D Navier-Stokes solver

    Energy Technology Data Exchange (ETDEWEB)

    Bertagnolio, F [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    The aim of this work is to model and study the dynamic interaction of the fluid flow with the structure which occurs when the blades of a wind turbine are passing in front of (or possibly behind) the tower. In order to capture the whole complexity of this phenomenon, the full unsteady Navier-Stokes equations for an incompressible fluid are used as a model. A new computational technique is described. For the sake of simplicity, we restrict ourselves to two-dimensional cases. The present methodology is illustrated by the computation of a wind turbine-like configuration in a periodic domain. (au)

  3. Optimizing Lidar Scanning Strategies for Wind Energy Measurements (Invited)

    Science.gov (United States)

    Newman, J. F.; Bonin, T. A.; Klein, P.; Wharton, S.; Chilson, P. B.

    2013-12-01

    Environmental concerns and rising fossil fuel prices have prompted rapid development in the renewable energy sector. Wind energy, in particular, has become increasingly popular in the United States. However, the intermittency of available wind energy makes it difficult to integrate wind energy into the power grid. Thus, the expansion and successful implementation of wind energy requires accurate wind resource assessments and wind power forecasts. The actual power produced by a turbine is affected by the wind speeds and turbulence levels experienced across the turbine rotor disk. Because of the range of measurement heights required for wind power estimation, remote sensing devices (e.g., lidar) are ideally suited for these purposes. However, the volume averaging inherent in remote sensing technology produces turbulence estimates that are different from those estimated by a sonic anemometer mounted on a standard meteorological tower. In addition, most lidars intended for wind energy purposes utilize a standard Doppler beam-swinging or Velocity-Azimuth Display technique to estimate the three-dimensional wind vector. These scanning strategies are ideal for measuring mean wind speeds but are likely inadequate for measuring turbulence. In order to examine the impact of different lidar scanning strategies on turbulence measurements, a WindCube lidar, a scanning Halo lidar, and a scanning Galion lidar were deployed at the Southern Great Plains Atmospheric Radiation Measurement (ARM) site in Summer 2013. Existing instrumentation at the ARM site, including a 60-m meteorological tower and an additional scanning Halo lidar, were used in conjunction with the deployed lidars to evaluate several user-defined scanning strategies. For part of the experiment, all three scanning lidars were pointed at approximately the same point in space and a tri-Doppler analysis was completed to calculate the three-dimensional wind vector every 1 second. In another part of the experiment, one of

  4. BOREAS TF-3 NSA-OBS Tower Flux, Meteorological, and Soil Temperature Data

    Science.gov (United States)

    Wofsy, Steven; Sutton, Doug; Goulden, Mike; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Tower Flux (BOREAS TF-3) team collected tower flux, surface meteorological, and soil temperature data at the BOREAS Northern Study Area-Old Black Spruce (NSA-OBS) site continuously from the March 1994 through October 1996. The data are available in tabular ASCII files.

  5. Integrated installation for offshore wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Way, J.; Bowerman, H.

    2003-07-01

    A project to investigate the feasibility of integrating the offshore installation of foundation, turbine and tower for offshore wind turbines into one operation is described. Three separate objectives are listed. They are: (1) Telescopic tower study - reversible process incorporating lift and lock mechanisms; (2) Transportation study - technical and economic feasibility of transporting and installing a wind turbine unit via a standard barge with minimal conversion and (3) Self-burial system study - to demonstrate the feasibility of self burial of a slab foundation via controlled jetting beneath the slab. The background to the study and the proposed concepts are discussed. The work carried out to date and the costs are reported together with the findings. Recommendations for future work are listed. The work was carried out by Corus UK Ltd and is managed by Future Energy Solutions for the DTI.

  6. Dynamic analysis of horizontal axis wind turbine by thin-walled beam theory

    Science.gov (United States)

    Wang, Jianhong; Qin, Datong; Lim, Teik C.

    2010-08-01

    A mixed flexible-rigid multi-body mathematical model is applied to predict the dynamic performance of a wind turbine system. Since the tower and rotor are both flexible thin-walled structures, a consistent expression for their deformations is applied, which employs a successive series of transformations to locate any point on the blade and tower relative to an inertial coordinate system. The kinetic and potential energy terms of each flexible body and rigid body are derived for use in the Lagrange approach to formulate the wind turbine system's governing equation. The mode shapes are then obtained from the free vibration solution, while the distributions of dynamic stress and displacement of the tower and rotor are computed from the forced vibration response analysis. Using this dynamic model, the influence of the tower's stiffness on the blade tip deformation is studied. From the analysis, it is evident that the proposed model not only inherits the simplicity of the traditional 1-D beam element, but also able to provide detailed information about the tower and rotor response due to the incorporation of the flexible thin-walled beam theory.

  7. Tower counts

    Science.gov (United States)

    Woody, Carol Ann; Johnson, D.H.; Shrier, Brianna M.; O'Neal, Jennifer S.; Knutzen, John A.; Augerot, Xanthippe; O'Neal, Thomas A.; Pearsons, Todd N.

    2007-01-01

    Counting towers provide an accurate, low-cost, low-maintenance, low-technology, and easily mobilized escapement estimation program compared to other methods (e.g., weirs, hydroacoustics, mark-recapture, and aerial surveys) (Thompson 1962; Siebel 1967; Cousens et al. 1982; Symons and Waldichuk 1984; Anderson 2000; Alaska Department of Fish and Game 2003). Counting tower data has been found to be consistent with that of digital video counts (Edwards 2005). Counting towers do not interfere with natural fish migration patterns, nor are fish handled or stressed; however, their use is generally limited to clear rivers that meet specific site selection criteria. The data provided by counting tower sampling allow fishery managers to determine reproductive population size, estimate total return (escapement + catch) and its uncertainty, evaluate population productivity and trends, set harvest rates, determine spawning escapement goals, and forecast future returns (Alaska Department of Fish and Game 1974-2000 and 1975-2004). The number of spawning fish is determined by subtracting subsistence, sport-caught fish, and prespawn mortality from the total estimated escapement. The methods outlined in this protocol for tower counts can be used to provide reasonable estimates ( plus or minus 6%-10%) of reproductive salmon population size and run timing in clear rivers. 

  8. Dependence of offshore wind turbine fatigue loads on atmospheric stratification

    International Nuclear Information System (INIS)

    Hansen, K S; Larsen, G C; Ott, S

    2014-01-01

    The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representing blade-bending and tower bottom bending, are combined with the operational statistics from the instrumented wind turbine as well as with meteorological statistics defining the inflow conditions. Only a part of all possible inflow conditions are covered through the approximately 8200 hours of combined measurements. The fatigue polar has been determined for an (almost) complete 360° inflow sector for both load sensors, representing mean wind speeds below and above rated wind speed, respectively, with the inflow conditions classified into three different stratification regimes: unstable, neutral and stable conditions. In general, impact of ABL stratification is clearly seen on wake affected inflow cases for both blade and tower fatigue loads. However, the character of this dependence varies significantly with the type of inflow conditions – e.g. single wake inflow or multiple wake inflow

  9. Water tower

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    The water tower, being built on the highest point of the site, 460.5 m above the sea level. The tank will hold 750 m3 of water, and the tower will be topped by a knob which can serve as a geological survey reference mark.

  10. The impact of a central Apennine wind-farm

    Directory of Open Access Journals (Sweden)

    Paolo Forconi

    2012-09-01

    Full Text Available We monitored raptors and investigated collision rate of birds with 2 turbines of a central Apennine wind-farm. We detected 1,18/raptors/km2/h. We have not found bird fatalities with turbines. We found 2 carcasses: one Subalpine Warbler, Sylvia cantillans, died by collision with a close communication tower and a Kestrel, Falco tinnunculus, died by electrocution with an MT power-line starting from the communication tower.

  11. Wind resource assessment handbook: Fundamentals for conducting a successful monitoring program

    International Nuclear Information System (INIS)

    Bailey, B.H.; McDonald, S.L.; Bernadett, D.W.; Markus, M.J.; Elsholz, K.V.

    1997-01-01

    This handbook presents industry-accepted guidelines for planning and conducting a wind resource measurement program to support a wind energy feasibility initiative. These guidelines, which are detailed and highly technical, emphasize the tasks of selecting, installing, and operating wind measurement equipment, as well as collecting and analyzing the associated data, once one or more measurement sites are located. The handbook's scope encompasses state-of-the-art measurement and analysis techniques at multiple heights on tall towers (e.g., 40 m) for a measurement duration of at least one year. These guidelines do not represent every possible method of conducting a quality wind measurement program, but they address the most important elements based on field-proven experience. The intended audience for this handbook is any organization or individual who desires the planning framework and detailed procedures for conducting a formally structured wind measurement program. Personnel from the management level to field technicians will find this material applicable. The organizational aspects of a measurement program, including the setting of clear program objectives and designing commensurate measurement and quality assurance plans, all of which are essential to ensuring the program's successful outcome, are emphasized. Considerable attention is also given to the details of actually conducting the measurement program in its many aspects, from selecting instrumentation that meets minimum performance standards to analyzing and reporting on the collected data. 5 figs., 15 tabs

  12. Large fog collectors: New strategies for collection efficiency and structural response to wind pressure

    Science.gov (United States)

    Holmes, Robert; Rivera, Juan de Dios; de la Jara, Emilio

    2015-01-01

    Most studies of large fog collectors (LFC) have focused on the collection efficiency, the amount of water collected, or economic and social aspects, but have not addressed the effects of strong winds on the system. Wind pressure is directly related to fog water collection efficiency but on the other hand may cause serious damage on the structure of LFCs. This study focuses in the effects of wind pressure on the components of the LFC as an integral system, and the ways to face strong winds with no significant damage. For this purpose we analysed cases of mechanical failure of LFCs both in our experimental station at Peña Blanca in Chile and elsewhere. The effects of wind pressure can be described as a sequence of physical processes, starting with the mesh deformation as a way of adapting to the induced stresses. For a big enough pressure, local stress concentrations generate a progressive rupture of the mesh. In cases where the mesh is sufficiently strong the wind force causes the partial or total collapse of the structure. Usually the weakest part is the mesh, especially close to where it is attached to the structure. The way the mesh is attached to the frame or cable of the structure is particularly important since it can induce significant stress concentrations. Mesh failure before the structure failure may be considered as a mechanical fuse, since it is cheaper to repair. However, more practical mechanical fuses can be conceived. In relation to structural performance and water collection efficiency, we propose a new design strategy that considers a three-dimensional spatial display of the collection screen, oblique incidence angle of wind on mesh and small mesh area between the supporting frame. The proposed design strategies consider both the wind pressure on mesh and structure and the collection efficiency as an integral solution for the LFC. These new design strategies are the final output of this research. Applying these strategies a multi-funnel LFC is

  13. Coupling Flux Towers and Networks with Proximal and Remote Sensing Data: New Tools to Collect and Share Time-Synchronized Hourly Fluxes

    Science.gov (United States)

    Burba, George; Avenson, Tom; Burkart, Andreas; Gamon, John; Guan, Kaiyu; Julitta, Tommaso; Pastorello, Gilberto; Sakowska, Karolina

    2017-04-01

    Multiple hundreds of flux towers are presently operational as standalone projects and as parts of larger networks. However, the vast majority of these towers do not allow straight-forward coupling with satellite data, and even fewer have optical sensors for validation of satellite products and upscaling from field to regional levels. In 2016, new tools to collect, process, and share time-synchronized flux data from multiple towers were developed and deployed globally. Originally designed to automate site and data management, these new tools can also be effective in coupling tower data with satellite data due to the following present capabilities: Fully automated FluxSuite system combines hardware, software and web-services, and does not require an expert to run it It can be incorporated into a new flux station or added to a present station, using weatherized remotely-accessible microcomputer, SmartFlux2 It utilizes EddyPro software to calculate fully-processed fluxes and footprints in near-realtime, alongside radiation, optical, weather and soil data All site data are merged into a single quality-controlled file timed using PTP time protocol Data from optical sensors can be integrated into this complete dataset via compatible dataloggers Multiple stations can be linked into time-synchronized network with automated reports and email alerts visible to PIs in real-time Remote sensing researchers without stations can form "virtual networks" of stations by collaborating with tower PIs from different physical networks The present system can then be utilized to couple ground data with satellite data via the following proposed concept: GPS-driven PTP protocol will synchronize instrumentation within the station, different stations with each other, and all of these to satellite data to precisely align optical and flux data in time Footprint size and coordinates computed and stored with flux data will help correctly align footprints and satellite motion to precisely align

  14. Analysis of Disturbance Source Inducing by The Variable Speed Wind Turbine System Forced Power Oscillations

    DEFF Research Database (Denmark)

    Tan, Jin; Hu, Weihao; Wang, Xiaoru

    2015-01-01

    The main focus of forced low frequency oscillations is to analyze the disturbance source and the origin of forced oscillations. In this paper, the origin of low-frequency periodical oscillations induced by wind turbines’ mechanical power is investigated and the mechanism is studied of fluctuating...... power transfer through permanent magnet generator wind turbine system. Considering the tower shadow and the wind shear effect, the mechanical and generator coupling model is developed by PSCAD. Simulation is done to analyze the impacts on output power of operation points and mechanical fluctuation...... components. It is shown that when the oscillation frequency of tower shadow coincides with the system natural frequency, it may cause forced oscillations, whereas, the wind shear and natural wind speed fluctuation are not likely to induce forced oscillations....

  15. Probabilistic Design of Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Toft, H.S.

    2010-01-01

    Probabilistic design of wind turbines requires definition of the structural elements to be included in the probabilistic basis: e.g., blades, tower, foundation; identification of important failure modes; careful stochastic modeling of the uncertain parameters; recommendations for target reliability....... It is described how uncertainties in wind turbine design related to computational models, statistical data from test specimens, results from a few full-scale tests and from prototype wind turbines can be accounted for using the Maximum Likelihood Method and a Bayesian approach. Assessment of the optimal...... reliability level by cost-benefit optimization is illustrated by an offshore wind turbine example. Uncertainty modeling is illustrated by an example where physical, statistical and model uncertainties are estimated....

  16. RBI Optimization of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ramírez, José G. Rangel; Sørensen, John Dalsgaard

    2009-01-01

    methods for oil & gas installations, a framework for optimal inspection and maintenance planning of offshore wind turbines is presented. Special aspects for offshore wind turbines considered are the fatigue loading characteristics where usually the wind loading are dominating the wave loading, wake......Wind turbines for electricity production have increased significantly the last years both in production capability and size. This development is expected to continue also in the coming years. Offshore wind turbines with an electricity production of 5-10 MW are planned. Typically, the wind turbine...... support structure is a steel structure consisting of a tower and a monopile, tripod or jacket type foundation. This paper considers aspects of inspection and maintenance planning of fatigue prone details in jacket and tripod type of wind turbine support structures. Based on risk-based inspection planning...

  17. Hard bottom substate monitoring Horns Rev offshore wind farm 2004. Survey report no. 1

    Energy Technology Data Exchange (ETDEWEB)

    Frederiksen, Rune

    2004-05-15

    In connection with the implementation of the monitoring programme concerning the ecological implication of the effect of the introduction of hard substrate related to the Horns Rev Wind Farm, the third survey was carried out in the period 2431 March 2004. The survey covered collection of fauna and flora samples from the scour protection and at the wind turbine towers at six turbine sites. Video recordings were planned at different sites to provide documentation, but due to poor visibility the video recordings were postponed. On request from Elsam Engineering A/S video inspections on technical installations were made at turbine '84 and 95. This report covers a short description of the methodology, sampling activities and site description. (au)

  18. Statistical Short-Range Guidance for Peak Wind Speed Forecasts on Kennedy Space Center/Cape Canaveral Air Force Station: Phase I Results

    Science.gov (United States)

    Lambert, Winifred C.; Merceret, Francis J. (Technical Monitor)

    2002-01-01

    This report describes the results of the ANU's (Applied Meteorology Unit) Short-Range Statistical Forecasting task for peak winds. The peak wind speeds are an important forecast element for the Space Shuttle and Expendable Launch Vehicle programs. The Keith Weather Squadron and the Spaceflight Meteorology Group indicate that peak winds are challenging to forecast. The Applied Meteorology Unit was tasked to develop tools that aid in short-range forecasts of peak winds at tower sites of operational interest. A 7 year record of wind tower data was used in the analysis. Hourly and directional climatologies by tower and month were developed to determine the seasonal behavior of the average and peak winds. In all climatologies, the average and peak wind speeds were highly variable in time. This indicated that the development of a peak wind forecasting tool would be difficult. Probability density functions (PDF) of peak wind speed were calculated to determine the distribution of peak speed with average speed. These provide forecasters with a means of determining the probability of meeting or exceeding a certain peak wind given an observed or forecast average speed. The climatologies and PDFs provide tools with which to make peak wind forecasts that are critical to safe operations.

  19. A wind turbine hybrid simulation framework considering aeroelastic effects

    Science.gov (United States)

    Song, Wei; Su, Weihua

    2015-04-01

    In performing an effective structural analysis for wind turbine, the simulation of turbine aerodynamic loads is of great importance. The interaction between the wake flow and the blades may impact turbine blades loading condition, energy yield and operational behavior. Direct experimental measurement of wind flow field and wind profiles around wind turbines is very helpful to support the wind turbine design. However, with the growth of the size of wind turbines for higher energy output, it is not convenient to obtain all the desired data in wind-tunnel and field tests. In this paper, firstly the modeling of dynamic responses of large-span wind turbine blades will consider nonlinear aeroelastic effects. A strain-based geometrically nonlinear beam formulation will be used for the basic structural dynamic modeling, which will be coupled with unsteady aerodynamic equations and rigid-body rotations of the rotor. Full wind turbines can be modeled by using the multi-connected beams. Then, a hybrid simulation experimental framework is proposed to potentially address this issue. The aerodynamic-dominant components, such as the turbine blades and rotor, are simulated as numerical components using the nonlinear aeroelastic model; while the turbine tower, where the collapse of failure may occur under high level of wind load, is simulated separately as the physical component. With the proposed framework, dynamic behavior of NREL's 5MW wind turbine blades will be studied and correlated with available numerical data. The current work will be the basis of the authors' further studies on flow control and hazard mitigation on wind turbine blades and towers.

  20. Endurance Wind Power : practical insights into small wind

    International Nuclear Information System (INIS)

    Hicks, D.

    2008-01-01

    This presentation discussed practical issues related to purchasing and installing small wind turbines in Canada. Wind power capacity can be estimated by looking at provincial wind maps as well as by seeking wind data at local airports. Wind resources are typically measured at heights of between 20 meters and 50 m. The height of a wind turbine tower can significantly increase the turbine's wind generating capacity. Turbine rotors should always be placed 30 feet higher than obstacles within 500 feet. Many provinces have now mandated utilities to accept renewable energy resources from grid-connected wind energy plants. Net billing systems are used to determine the billing relationship between power-producing consumers and the utilities who will buy the excess power and sell it to other consumers. Utilities are not yet mandated to purchase excess power, and it is likely that federal and provincial legislation will be needed to ensure that net billing systems continue to grow. Many Canadian municipalities have no ordinances related to wind turbine placements. Consumers interested in purchasing small wind turbines should ensure that the turbine has been certified by an accredited test facility and has an adequate safety system. The noise of the turbine as well as its power performance in relation to the purchaser's needs must also be considered. It was concluded that small wind turbines can provide a means for electricity consumers to reduce their carbon footprint and hedge against the inflationary costs of fossil-fuelled energy resources. tabs., figs

  1. Structural Control of a Wind Turbine Accounting for Second Order Effects

    Science.gov (United States)

    Caterino, Nicola; Spizzuoco, Mariacristina

    2017-10-01

    The negative impact of the use of fossil fuels on the environment has lead to a boom in the production of wind turbines. The progressively increasing turbines’ height, decided to take ad-vantage of the smoother winds at higher altitude, has led to an increased demand to control tower forces. The proposed work is focused on the application of a semi-active (SA) control system to limit bending moment demand at the base of a wind turbine by relaxing the base restraint of the turbine’s tower, without increasing the top displacement. The proposed SA control system reproduces a variable restraint at the base that changes in real time its mechanical properties according to the instantaneous response of the turbine’s tower. This smart restraint is made of a central smooth hinge, elastic springs and SA magnetorheological dampers driven by a properly designed control algorithm. A commercial 105 m tall wind turbine has been considered as a case study. Several numerical simulations have been performed with reference to two extreme loads, different one each other for intensity, duration, frequency content, so as to understand if a unique optimal configuration of the controller can be defined for both of them. The proposed study is also focused on understanding whether and how to reduce the residual top displacement due to the possible incremental base rotation that may happen during a wind load history, especially when it is long lasting.

  2. Calculation and design of steel bearing structure for wind turbine

    Directory of Open Access Journals (Sweden)

    Bešević Miroslav

    2014-01-01

    Full Text Available Wind represents directed movement of the air and is caused by differences in atmospheric pressure which are caused by uneven heating of air masses. Global and local winds can be distinguished. Global winds have high altitude, while local winds occur in the ground layer of the atmosphere. Given that the global wings have high altitude they cannot be used as propellant for wind generators, but they should be known for their effects on the winds in the lower atmosphere. Modern wind turbines are made with a horizontal axle that has a system for the swiveling axis in the horizontal plane for tracking wind direction changes. They can have different number of blades, but for larger forces three blades are commonly used because they provide the greatest efficiency. Rotor diameter of these turbines depends on the strength and it ranges from 30 m for the power of 300 kW to 115 m for the power of 5 MW. Wind turbines are mounted on vertical steel tower which can be high even more than 100 m. Depending on the diameter of the turbine rotor, column is usually built as steel conical and less often as a steel-frame. This study includes analysis and design of steel tower for wind generator made by manufacturer Vestas, type V112 3MW HH 119 (power 3.2 MW for the construction of wind farm 'Kovačica'.

  3. Sensitivity study of a method for updating a finite element model of a nuclear power station cooling tower

    International Nuclear Information System (INIS)

    Billet, L.

    1994-01-01

    The Research and Development Division of Electricite de France is developing a surveillance method of cooling towers involving on-site wind-induced measurements. The method is supposed to detect structural damage in the tower. The damage is identified by tuning a finite element model of the tower on experimental mode shapes and eigenfrequencies. The sensitivity of the method was evaluated through numerical tests. First, the dynamic response of a damaged tower was simulated by varying the stiffness of some area of the model shell (from 1 % to 24 % of the total shell area). Second, the structural parameters of the undamaged cooling tower model were updated in order to make the output of the undamaged model as close as possible to the synthetic experimental data. The updating method, based on the minimization of the differences between experimental modal energies and modal energies calculated by the model, did not detect a stiffness change over less than 3 % of the shell area. Such a sensitivity is thought to be insufficient to detect tower cracks which behave like highly localized defaults. (author). 8 refs., 9 figs., 6 tabs

  4. Review of control algorithms for offshore wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Spruce, C J; Markou, H; Leithead, W E; Dominguez Ruiz, S

    2005-07-01

    Innovative turbine control strategies could allow the improvements to cost and performance considered essential to reduce the cost of energy from offshore wind farms around the UK. This project reviewed and investigated the possibility for further development of a power control algorithm originally developed by NEG Micon Rotors Ltd for use with offshore wind turbines in the hope that more advanced algorithms would reduce the loads on, and hence the costs of, components such as the foundation/support structure, tower, blades and bedplate. Three models (simulation model, linearisation of the simulation model and control model) were produced in order to conduct the review. Application of these models produced the conclusion that the size of the latest generation of offshore wind turbines has now reached a level where performance is starting to be constrained by fundamental factors in the dynamics caused by the machine's physical size. It was also concluded that an ideal control strategy could achieve potential cost savings for the tower and support structure of 5-10% of the total cost of the turbine plus support structure. Further work to develop controllers to reduce loads in the tower and support structure is urged. The report considers non-linear simulation, the linear model, the control model, general operation of the controller, the drive train damping filter, torque control, pitch control and advanced algorithms, and makes detailed recommendations for future work.

  5. Strengthening of tower-like structures. Typical cases of weakening and their repair; Verstaerkung turmartiger Bauwerke. Typische Schwaechungen und ihre Behebung

    Energy Technology Data Exchange (ETDEWEB)

    Noakowski, Piotr; Breddermann, Martin; Harling, Andreas; Rost, Markus; Potratz, Sabine; Leszinski, Holger [FaAA - Failure Analysis Associates Engineering und Forschung im Bauwesen, Duesseldorf (Germany)

    2010-01-15

    In view of our cramped built-up environment, the further use of existing tower-like structures is of high importance. Many of those structures need strengthening which has different causes: sensitive structural design according to old standards and experiences; distinct aging due to severe operation, lack of maintenance and frequent shut down; insufficient wind bearing capacity for upgrading with platforms and antennas; change of the chimney operation to hot or wet flue gases; some flaws in the original structural solutions. The paper describes several strengthening methods for concrete towers, masonry towers, and concrete masts. The projects regard locations of cell phone masts and industrial chimneys which are not specified here. (orig.)

  6. The collection of the main issues for wind farm optimisation in complex terrain

    DEFF Research Database (Denmark)

    Xu, Chang; Chen, Dandan; Han, Xingxing

    2016-01-01

    The paper aims at establishing the collection of the main issues for wind farm optimisation in complex terrain. To make wind farm cost effective, this paper briefly analyses the main factors influencing wind farm design in complex terrain and sets up a series of mathematical model that includes...... micro-siting, collector circuits, access roads design for optimization problems. The paper relies on the existing one year wind data in the wind farm area and uses genetic algorithm to optimize the micro-siting problem. After optimization of the turbine layout, single-source shortest path algorithm...

  7. Dynamic Model of a Wind Turbine for the Electric Energy Generation

    Directory of Open Access Journals (Sweden)

    José de Jesús Rubio

    2014-01-01

    Full Text Available A novel dynamic model is introduced for the modeling of the wind turbine behavior. The objective of the wind turbine is the electric energy generation. The analytic model has the characteristic that considers a rotatory tower. Experiments show the validity of the proposed method.

  8. Origin and prevention of infection with Legionella pneumophila through cooling towers and evaporative cooling towers

    International Nuclear Information System (INIS)

    Schulze-Roebbecke, R.

    1994-01-01

    Evaporative cooling towers and industrial ventilator cooling towers have repeatedly been described as the origin of Legionnaires' disease. This article describes the design and function of cooling towers and evaporative cooling towers, sums up knowledge on the colonization of such systems with Legionella pneumophila, and describes conditions permitting the transmission of Legionella. Furthermore, design, maintenance, cleaning and disinfection measures are indicated which are believed to reduce the risk of infection through industrial and evaporative cooling towers. (orig.) [de

  9. Temperature profile and water depth data collected from TOWERS in the NE Atlantic (limit-180 W) from 06 June 1986 to 29 August 1986 (NODC Accession 8600378)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the TOWERS in the Northeast Atlantic Ocean, South China Sea, Philippine Sea, and...

  10. The effect of the Sep wind park near Oosterbierum, Friesland, The Netherlands, on birds

    International Nuclear Information System (INIS)

    Winkelman, J.E.

    1992-01-01

    The title study concerns the period 1984-1991. The wind park consists of 18 three-bladed 300 kW horizontal axis wind turbines of 35 meters height, and a rotor diameter of 30 meters, seven meteorological towers, and three cluster and control buildings. Aspects studied included disturbance of breeding, resting or feeding, and migrating birds, behavior of birds approaching the wind turbines during the day and night, and bird victims due to collision with the wind turbines and the meteorological towers. In this report data on the number of birds passing the wind park at night and the flight behavior of these birds during their passage are presented and discussed. The numbers were determined in the period 1985-1988 by using a search approach radar, two passive image intensifiers in combination with infrared spot lights, and a thermal image intensifier. Illumination of the wind turbines to avoid collisions is not believed to be necessary, because birds seem to be quite good at spotting the wind turbines, even during conditions of moderate visibility at night. 30 figs., 23 tabs., 18 app., 109 refs

  11. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanting Hu

    2013-07-01

    Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

  12. Tower of Hanoi disk-transfer task: Influences of strategy knowledge and learning on performance

    NARCIS (Netherlands)

    Welsh, M.C.; Huizinga, M.

    2005-01-01

    Tower of Hanoi has become a popular tool in cognitive and neuropsychology to assess a set of behaviors collectively referred to as executive functions. Substantial variability in performance on the Tower of Hanoi (TOH) disk-transfer task among normally functioning young adults, and potential

  13. A proposed national wind power R and D program. [offshore wind power system for electric energy supplies

    Science.gov (United States)

    Heronemus, W.

    1973-01-01

    An offshore wind power system is described that consists of wind driven electrical dc generators mounted on floating towers in offshore waters. The output from the generators supplies underwater electrolyzer stations in which water is converted into hydrogen and oxygen. The hydrogen is piped to shore for conversion to electricity in fuel cell stations. It is estimated that this system can produce 159 x 10 to the ninth power kilowatt-hours per year. It is concluded that solar energy - and that includes wind energy - is the only way out of the US energy dilemma in the not too distant future.

  14. Response Analysis of an RC Cooling Tower Under Seismic and Windstorm Effects

    Directory of Open Access Journals (Sweden)

    D. Makovička

    2006-01-01

    Full Text Available The paper compares the RC structure of a cooling tower unit under seismic loads and under strong wind loads. The calculated values of the envelopes of the displacements and the internal forces due to seismic loading states are compared with the envelopes of the loading states due to the dead, operational and live loads, wind and temperature actions. The seismic effect takes into account the seismic area of ground motion 0.3 g and the ductility properties of a relatively rigid structure. The ductility is assessed as the reduction in seismic load. In this case the actions of wind pressure are higher than the seismicity effect under ductility correction. The seismic effects, taking into account the ductility properties of the structure, are lower than the actions of the wind pressure. The other static loads, especially temperature action due to the environment and surface insulation are very important for the design of the structure. 

  15. Field measurements in the wake of a model wind turbine

    International Nuclear Information System (INIS)

    Pol, Suhas; Taylor, Amelia; Doostalab, Ali; Novoa, Santiago; Castillo, Luciano; Bilbao, Argenis; Sheng, Jian; Giesselmann, Michael; Westergaard, Carsten; Hussain, Fazle; Ren, Beibei; Glauser, Mark

    2014-01-01

    As a first step to study the dynamics of a wind farm' we experimentally explored the flow field behind a single wind turbine of diameter 1.17 m at a hub height of 6.25 m. A 10 m tower upstream of the wind farm characterizes the atmospheric conditions and its influence on the wake evolution. A vertical rake of sonic anemometers is clustered around the hub height on a second tower' 6D downstream of the turbine. We present preliminary observations from a 1- hour block of data recorded in near-neutral atmospheric conditions. The ratio of the standard deviation of power to the inflow velocity is greater than three' revealing adverse effects of inflow turbulence on the power and load fluctuations. Furthermore' the wake defect and Reynolds stress and its gradient are pronounced at 6D. The flux of energy due to Reynolds stresses is similar to that reported in wind tunnel studies. The swirl and mixing produces a constant temperature wake which results in a density jump across the wake interface. Further field measurements will explore the dynamics of a model wind farm' including the effects of atmospheric variability

  16. Recommended practices for wind farm data collection and reliability assessment for O&M optimization

    DEFF Research Database (Denmark)

    Hahn, Berthold; Welte, Thomas; Faulstich, Stefan

    2017-01-01

    . The complete results of IEA Wind Task 33 are described in the expert group report on recommended practices for "Wind farm data collection and reliability assessment for O&M optimization" which will be published by IEA Wind in 2017. This paper briefly presents the background of the work, the recommended process...

  17. Power electronic solutions for interfacing offshore wind turbine generators to medium voltage DC collection grids

    Science.gov (United States)

    Daniel, Michael T.

    Here in the early 21st century humanity is continuing to seek improved quality of life for citizens throughout the world. This global advancement is providing more people than ever with access to state-of-the-art services in areas such as transportation, entertainment, computing, communication, and so on. Providing these services to an ever-growing population while considering the constraints levied by continuing climate change will require new frontiers of clean energy to be developed. At the time of this writing, offshore wind has been proven as both a politically and economically agreeable source of clean, sustainable energy by northern European nations with many wind farms deployed in the North, Baltic, and Irish Seas. Modern offshore wind farms are equipped with an electrical system within the farm itself to aggregate the energy from all turbines in the farm before it is transmitted to shore. This collection grid is traditionally a 3-phase medium voltage alternating current (MVAC) system. Due to reactive power and other practical constraints, it is preferable to use a medium voltage direct current (MVDC) collection grid when siting farms >150 km from shore. To date, no offshore wind farm features an MVDC collection grid. However, MVDC collection grids are expected to be deployed with future offshore wind farms as they are sited further out to sea. In this work it is assumed that many future offshore wind farms may utilize an MVDC collection grid to aggregate electrical energy generated by individual wind turbines. As such, this work presents both per-phase and per-pole power electronic converter systems suitable for interfacing individual wind turbines to such an MVDC collection grid. Both interfaces are shown to provide high input power factor at the wind turbine while providing DC output current to the MVDC grid. Common mode voltage stress and circulating currents are investigated, and mitigation strategies are provided for both interfaces. A power sharing

  18. Detection of Damage in Operating Wind Turbines by Signature Distances

    Directory of Open Access Journals (Sweden)

    James F. Manwell

    2013-01-01

    Full Text Available Wind turbines operate in the atmospheric boundary layer and are subject to complex random loading. This precludes using a deterministic response of healthy turbines as the baseline for identifying the effect of damage on the measured response of operating turbines. In the absence of such a deterministic response, the stochastic dynamic response of the tower to a shutdown maneuver is found to be affected distinctively by damage in contrast to wind. Such a dynamic response, however, cannot be established for the blades. As an alternative, the estimate of blade damage is sought through its effect on the third or fourth modal frequency, each found to be mostly unaffected by wind. To discern the effect of damage from the wind effect on these responses, a unified method of damage detection is introduced that accommodates different responses. In this method, the dynamic responses are transformed to surfaces via continuous wavelet transforms to accentuate the effect of wind or damage on the dynamic response. Regions of significant deviations between these surfaces are then isolated in their corresponding planes to capture the change signatures. The image distances between these change signatures are shown to produce consistent estimates of damage for both the tower and the blades in presence of varying wind field profiles.

  19. Statistical Validation of Calibrated Wind Data Collected From NOAA's Hurricane Hunter Aircraft

    Science.gov (United States)

    Graham, K.; Sears, I. T.; Holmes, M.; Henning, R. G.; Damiano, A. B.; Parrish, J. R.; Flaherty, P. T.

    2015-12-01

    Obtaining accurate in situ meteorological measurements from the NOAA G-IV Hurricane Hunter Aircraft currently requires annual wind calibration flights. This project attempts to demonstrate whether an alternate method to wind calibration flights can be implemented using data collected from many previous hurricane, winter storm, and surveying flights. Wind derivations require using airplane attack and slip angles, airplane pitch, pressure differentials, dynamic pressures, ground speeds, true air speeds, and several other variables measured by instruments on the aircraft. Through the use of linear regression models, future wind measurements may be fit to past statistical models. This method of wind calibration could replace the need for annual wind calibration flights, decreasing NOAA expenses and providing more accurate data. This would help to ensure all data users have reliable data and ultimately contribute to NOAA's goal of building of a Weather Ready Nation.

  20. The use of real-time off-site observations as a methodology for increasing forecast skill in prediction of large wind power ramps one or more hours ahead of their impact on a wind plant.

    Energy Technology Data Exchange (ETDEWEB)

    Martin Wilde, Principal Investigator

    2012-12-31

    ABSTRACT Application of Real-Time Offsite Measurements in Improved Short-Term Wind Ramp Prediction Skill Improved forecasting performance immediately preceding wind ramp events is of preeminent concern to most wind energy companies, system operators, and balancing authorities. The value of near real-time hub height-level wind data and more general meteorological measurements to short-term wind power forecasting is well understood. For some sites, access to onsite measured wind data - even historical - can reduce forecast error in the short-range to medium-range horizons by as much as 50%. Unfortunately, valuable free-stream wind measurements at tall tower are not typically available at most wind plants, thereby forcing wind forecasters to rely upon wind measurements below hub height and/or turbine nacelle anemometry. Free-stream measurements can be appropriately scaled to hub-height levels, using existing empirically-derived relationships that account for surface roughness and turbulence. But there is large uncertainty in these relationships for a given time of day and state of the boundary layer. Alternatively, forecasts can rely entirely on turbine anemometry measurements, though such measurements are themselves subject to wake effects that are not stationary. The void in free-stream hub-height level measurements of wind can be filled by remote sensing (e.g., sodar, lidar, and radar). However, the expense of such equipment may not be sustainable. There is a growing market for traditional anemometry on tall tower networks, maintained by third parties to the forecasting process (i.e., independent of forecasters and the forecast users). This study examines the value of offsite tall-tower data from the WINDataNOW Technology network for short-horizon wind power predictions at a wind farm in northern Montana. The presentation shall describe successful physical and statistical techniques for its application and the practicality of its application in an operational

  1. Long-term Measurements of Summer-time Ozone at the Walnut Grove Tower - Understanding Trends in the Boundary Layer

    Science.gov (United States)

    Mahmud, A.; Di, P.; Mims, D.; Avise, J.; DaMassa, J.; Kaduwela, A. P.

    2015-12-01

    The California Air Resources Board (CARB) has been monitoring boundary layer ozone at the Walnut Grove Tower (WGT) since 1996 for investigating regional transport and vertical profile. Walnut Grove is located between Sacramento and Stockton, CA in the Sacramento - San Joaquin Delta. Sampling inlets are positioned at 30-ft, 400-ft, 800-ft, 1200-ft and 1600-ft levels of the 2000-ft tower, which is one of the tallest monitoring towers in the Western US. Ozone, ambient temperature, wind speed, and wind direction are simultaneously measured at each level, and reported as hourly averages. The current study included analyses of available ozone and corresponding meteorological data for the months of June - September from 1996 - 2014 with objectives to: 1) explore trends and inter-annual variability of ozone, 2) examine any correlations between ozone and meteorological parameters, 3) understand interactions of ozone measured at various levels, and 4) assess how well a regulatory state-of-the-science air quality model such as the Community Multi-scale Air Quality Model (CMAQ) captures observation. Daily 1-hr maximum ozone has been consistently decreasing during the 1996 - 2014 period at a rate of ~1 ppb per year. This indicates that CARB's measures to control ambient ozone have been effective over the past years. Evolution of the vertical profile throughout the day shows that ozone is fairly homogeneously mixed between 1 - 5 pm, when mixing height typically reaches the maximum. Ozone at 30-ft shows the greatest variability because of its proximity to the ground and emissions sources - rises faster during morning hours (7 - 10 am) and declines more rapidly during evening hours (7 - 10 pm) compared to other levels. Air masses reaching the tower are predominantly southwesterly (247 - 257 deg.) at the bottom, and southwesterly to slightly northwesterly (254 - 302 deg.) at top levels. Daily 1-hr maximum ozone was negatively correlated with wind speed (i.e. ozone was high under

  2. A smart base restraint for wind turbines to mitigate undesired effects due to structural vibrations

    DEFF Research Database (Denmark)

    Caterino, N.; Georgakis, Christos T.; Spizzuoco, M.

    2016-01-01

    Concerns in the last decades of the negative impact of the use of fossil fuels on the environment has lead to a boom in the production of wind turbines. To take advantage of the smoother stronger winds at height, wind turbine heights are progressively increasing. This has led to an increased demand...... to control tower forces. The application of a semi-active (SA) control system is herein proposed and discussed. Its aim is to limit bending moment demand at the base of a wind turbine by relaxing the base restraint of the turbine's tower, without increasing the top displacement. This is done thanks....... This smart restraint is made of a central smooth hinge, elastic springs and SA magnetorheological dampers driven by a control algorithm properly designed for the specific application. A commercial 105 m tall wind turbine has been assumed as a case study. Several numerical simulations have been performed...

  3. On the stringy nature of winding modes in noncommutative thermal field theories

    CERN Document Server

    Arcioni, G; Gomis, J P; Vázquez-Mozo, Miguel Angel; Gomis, Joaquim

    2000-01-01

    We show that thermal noncommutative field theories admit a version of `channel duality' reminiscent of open/closed string duality, where non-planar thermal loops can be replaced by an infinite tower of tree-level exchanges of effective fields. These effective fields resemble closed strings in three aspects: their mass spectrum is that of closed-string winding modes, their interaction vertices contain extra moduli, and they can be regarded as propagating in a higher-dimensional `bulk' space-time. In noncommutative models that can be embedded in a D-brane, we show the precise relation between the effective `winding fields' and closed strings propagating off the D-brane. The winding fields represent the coherent coupling of the infinite tower of closed-string oscillator states. We derive a sum rule that expresses this effective coupling in terms of the elementary couplings of closed strings to the D-brane. We furthermore clarify the relation between the effective propagating dimension of the winding fields and t...

  4. Enormous achievement of the wind power in India; Indo no fusha no osorubeki jitsuryoku

    Energy Technology Data Exchange (ETDEWEB)

    Ida, H

    1996-10-27

    This paper presents the situation of the wind power generation in India. Indian wind turbine capacity sums to 600MW as the 4th power in the world. The financial combine NEPC has erected 3/4 of the total capacity. The joint enterprise NEPC-MYCON of NEPC and Danish wind turbine manufacturer imports main bodies, and produces only towers in India. The enterprise erected 1,500 systems (450MW) in 1989-95 receiving benefit from cheaper real estate and labor costs. As the author visited the wind farm including 10 250kW class wind power generation systems erected in 1994, wind velocity was a maximum of 6.3m/s, however, it is 10m/s on average in the monsoon period from April to July. The blades of wind turbines under erection are made of fiber reinforced plastics water-proofed by polyester resin. Generated power is sold to local governments, or wind turbines are sold to various private enterprises for private power generation or to local governments. Erection cost can be collected with power sales benefit by 6 years. Since power supply capability in India is only 40% of power demand, low-cost wind power generation is promising. 5 figs.

  5. Improve crossflow cooling tower operation

    International Nuclear Information System (INIS)

    Burger, R.

    1989-01-01

    This paper reports how various crossflow cooling tower elements can be upgraded. A typical retrofit example is presented. In the past decade, cooling tower technology has progressed. If a cooling tower is over ten years old, chances are the heat transfer media and mechanical equipment were designed over 30 to 40 years ago. When a chemical plant expansion is projected or a facility desires to upgrade its equipment for greater output and energy efficiency, the cooling tower is usually neglected until someone discovers that the limiting factor of production is the quality of cold water returning from the cooling tower

  6. Good Towers of Function Fields

    DEFF Research Database (Denmark)

    Bassa, Alp; Beelen, Peter; Nguyen, Nhut

    2014-01-01

    In this paper, we will give an overview of known and new techniques on how one can obtain explicit equations for candidates of good towers of function fields. The techniques are founded in modular theory (both the classical modular theory and the Drinfeld modular theory). In the classical modular...... setup, optimal towers can be obtained, while in the Drinfeld modular setup, good towers over any non-prime field may be found. We illustrate the theory with several examples, thus explaining some known towers as well as giving new examples of good explicitly defined towers of function fields....

  7. Transportation of Large Wind Components: A Permitting and Regulatory Review

    Energy Technology Data Exchange (ETDEWEB)

    Levine, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cook, Jeff [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    This report summarizes permitting and regulatory issues associated with transporting wind turbine blades, towers, and nacelles as well as large transformers (wind components). These wind components are commonly categorized as oversized and overweight (OSOW) and require specific permit approvals from state and local jurisdictions. The report was developed based on a Quadrennial Energy Review (QER) recommendation on logistical requirements for the transportation of 'oversized or high-consequence energy materials, equipment, and components.'

  8. Wind turbine noise diagnostics

    International Nuclear Information System (INIS)

    Richarz, W.; Richarz, H.

    2009-01-01

    This presentation proposed a self-consistent model for broad-band noise emitted from modern wind turbines. The simple source model was consistent with the physics of sound generation and considered the unique features of wind turbines. Although the acoustics of wind turbines are similar to those of conventional propellers, the dimensions of wind turbines pose unique challenges in diagnosing noise emission. The general features of the sound field were deduced. Source motion and source directivity appear to be responsible for amplitude variations. The amplitude modulation is likely to make wind-turbine noise more audible, and may be partly responsible for annoyance that has been reported in the literature. Acoustic array data suggests that broad-band noise is emitted predominantly during the downward sweep of each rotor blade. Source motion and source directivity account for the observed pattern. Rotor-tower interaction effects are of lesser importance. Predicted amplitude modulation ranges from 1 dB to 6dB. 2 refs., 9 figs.

  9. Performance comparison of control schemes for variable-speed wind turbines

    Science.gov (United States)

    Bottasso, C. L.; Croce, A.; Savini, B.

    2007-07-01

    We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies.

  10. Performance comparison of control schemes for variable-speed wind turbines

    International Nuclear Information System (INIS)

    Bottasso, C L; Croce, A; Savini, B

    2007-01-01

    We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies

  11. Review of control algorithms for offshore wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Spruce, C.J.; Markou, H.; Leithead, W.E.; Dominguez Ruiz, S.

    2005-07-01

    Innovative turbine control strategies could allow the improvements to cost and performance considered essential to reduce the cost of energy from offshore wind farms around the UK. This project reviewed and investigated the possibility for further development of a power control algorithm originally developed by NEG Micon Rotors Ltd for use with offshore wind turbines in the hope that more advanced algorithms would reduce the loads on, and hence the costs of, components such as the foundation/support structure, tower, blades and bedplate. Three models (simulation model, linearisation of the simulation model and control model) were produced in order to conduct the review. Application of these models produced the conclusion that the size of the latest generation of offshore wind turbines has now reached a level where performance is starting to be constrained by fundamental factors in the dynamics caused by the machine's physical size. It was also concluded that an ideal control strategy could achieve potential cost savings for the tower and support structure of 5-10% of the total cost of the turbine plus support structure. Further work to develop controllers to reduce loads in the tower and support structure is urged. The report considers non-linear simulation, the linear model, the control model, general operation of the controller, the drive train damping filter, torque control, pitch control and advanced algorithms, and makes detailed recommendations for future work.

  12. Unconventional wind machine

    International Nuclear Information System (INIS)

    Sheff, J.R.

    1979-01-01

    It is the purpose of this paper to introduce an unconventional wind machine which has economics comparable with nuclear power and is already available in the public market place. Specifically, up to about 17 MWE could be saved for other uses such as sale in most 1000 MWE plants of any type - nuclear, oil, gas, peat, or wood - which use conventional electrically driven fans in their cooling towers. 10 refs

  13. Establishing a Comprehensive Wind Energy Program

    Energy Technology Data Exchange (ETDEWEB)

    Fleeter, Sanford [Purdue University

    2012-09-30

    This project was directed at establishing a comprehensive wind energy program in Indiana, including both educational and research components. A graduate/undergraduate course ME-514 - Fundamentals of Wind Energy has been established and offered and an interactive prediction of VAWT performance developed. Vertical axis wind turbines for education and research have been acquired, instrumented and installed on the roof top of a building on the Calumet campus and at West Lafayette (Kepner Lab). Computational Fluid Dynamics (CFD) calculations have been performed to simulate these urban wind environments. Also, modal dynamic testing of the West Lafayette VAWT has been performed and a novel horizontal axis design initiated. The 50-meter meteorological tower data obtained at the Purdue Beck Agricultural Research Center have been analyzed and the Purdue Reconfigurable Micro Wind Farm established and simulations directed at the investigation of wind farm configurations initiated. The virtual wind turbine and wind turbine farm simulation in the Visualization Lab has been initiated.

  14. Reliability Assessment Of Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2014-01-01

    Reduction of cost of energy for wind turbines are very important in order to make wind energy competitive compared to other energy sources. Therefore the turbine components should be designed to have sufficient reliability but also not be too costly (and safe). This paper presents models...... for uncertainty modeling and reliability assessment of especially the structural components such as tower, blades, substructure and foundation. But since the function of a wind turbine is highly dependent on many electrical and mechanical components as well as a control system also reliability aspects...... of these components are discussed and it is described how there reliability influences the reliability of the structural components. Two illustrative examples are presented considering uncertainty modeling, reliability assessment and calibration of partial safety factors for structural wind turbine components exposed...

  15. Reliability Analysis of Cooling Towers: Influence of Rebars Corrosion on Failure

    International Nuclear Information System (INIS)

    Sudret, Bruno; Pendola, Maurice

    2002-01-01

    Natural-draught cooling towers are used in nuclear power plants as heat exchangers. These structures are submitted to environmental loads such as wind and thermal gradients that are stochastic in nature. A probabilistic framework has been developed by EDF (Electricite de France) for assessing the durability of such structures. In this paper, the corrosion of the rebars due to concrete carbonation and the corresponding weakening of the reinforced concrete sections is considered. Due to the presence of time in the definition of the limit state function associated with the loss of serviceability of the cooling tower, time-variant reliability analysis has to be used. A novel approach is proposed to take into account the random 'initiation time', which corresponds to the time necessary for the carbonation to attain the rebars. Results are given in terms of the probability of failure of the structure over its life time. (authors)

  16. Modeling of existing cooling towers in ASPEN PLUS using an equilibrium stage method

    International Nuclear Information System (INIS)

    Queiroz, João A.; Rodrigues, Vitor M.S.; Matos, Henrique A.; Martins, F.G.

    2012-01-01

    Highlights: ► Simulation of cooling tower performance under different operating conditions. ► Cooling tower performance is simulated using ASPEN PLUS. ► Levenberg–Marquardt method used to adjust model parameters. ► Air and water outlet temperatures are in good accordance with experimental data. - Abstract: Simulation of cooling tower performance considering operating conditions away from design is typically based on the geometrical parameters provided by the cooling tower vendor, which are often unavailable or outdated. In this paper a different approach for cooling tower modeling based on equilibrium stages and Murphree efficiencies to describe heat and mass transfer is presented. This approach is validated with published data and with data collected from an industrial application. Cooling tower performance is simulated using ASPEN PLUS. Murphree stage efficiency values for the process simulator model were optimized by minimizing the squared difference between the experimental and calculated data using the Levenberg–Marquardt method. The minimization algorithm was implemented in Microsoft Excel with Visual Basic for Applications, integrated with the process simulator (ASPEN PLUS) using Aspen Simulation Workbook. The simulated cooling tower air and water outlet temperatures are in good accordance with experimental data when applying only the outlet water temperature to calibrate the model. The methodology is accurate for simulating cooling towers at different operational conditions.

  17. BOREAS AFM-06 Mean Wind Profile Data

    Science.gov (United States)

    Wilczak, James; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-6 team from the National Oceanic and Atmospheric Administration/Environment Technology Laboratory (NOAA/ETL) operated a 915-MHz wind/Radio Acoustic Sounding System (RASS) profiler system in the Southern Study Area (SSA) near the Old Jack Pine (OJP) tower from 21 May 1994 to 20 Sep 1994. The data set provides wind profiles at 38 heights, containing the variables of wind speed; wind direction; and the u-, v-, and w-components of the total wind. The data are stored in tabular ASCII files. The mean wind profile data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  18. Wind tunnel experiments on cooling tower plumes. Pt. 2

    International Nuclear Information System (INIS)

    Andreopoulos, J.

    1986-01-01

    The basic characteristics of plumes issuing into a boundary layer type of cross flow are reported. The flow can be considered as an interaction between two vorticity fields with different length scales and turbulence intensities. The large eddies of the oncoming boundary layer are responsible for the observed sudden changes in the plume direction. The type of structures emanating the tower depends on the instantaneous velocity ratio. Mean velocities and normal velocity gradients are smaller than in the case of uniform cross-flow (Andreopoulos, 1986) and therefore the measured turbulence intensities were lower too. The cross-stream turbulence brings high momentum fluid into the wake region and the velocity defect decays very rapidly. Dilution of the plumes takes place faster in the presence of external turbulence than in the case with uniform cross-flow. The spreading rate is increased dramatically by the external turbulence which causes different effects on the hydrodynamic and thermal fields. (orig.) [de

  19. Assessment of Economic Feasibility on Promising Wind Energy Sites in Myanmar

    OpenAIRE

    Soe, Thi Thi; Zheng, Maosheng; Aung, Zar Ni

    2016-01-01

    Due to lack of reliable wind data measured on site by high tower mast, the preliminarily wind atlas of Myanmar is forecasted with Modern Era Retrospective-analysis for Research and Application (MERRA) reanalysis data using in ArcGIS. From the result wind- map, the promising areas were found in Arakan, Pathein, Yangon, Ye which lie at coastal area in Myanmar and of which wind power density can be used for village power application with isolated-grid. To evaluate the annual energy production of...

  20. Advantages on monitoring wind turbine nacelle oscillation

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Marhadi, Kun Saptohartyadi; Hilmisson, Reynir

    2015-01-01

    and vibrations on blades, tower and drive train components, which may jeopardize their working condition. The present paper deals with the comparison and analysis of vibration signals from wind turbines subjected to various failure modes and operating conditions, such as blade misalignment, pitch malfunction...

  1. Wind energy in the Mediterranean countries

    International Nuclear Information System (INIS)

    Gaudiosi, G.

    1992-01-01

    This paper reviews the main findings relative to the European Communities OPET (Organization for the Promotion of Energy Technology) June 1992 conference on the potential for small and medium size wind energy applications in the Mediterranean countries and gives a panoramic look at progress being made by these countries in the development and use of wind energy turbines. One system which appears to be promising is the Danish 100 kW 'Bonus' wind turbine (23 m rotor, 30 m tower height) which has seen successful applications at a seaside resort and at a remote radio station in terms of performance, environmental compatibility and public acceptance

  2. Meteorological effects of the mechanical-draft cooling towers of the Oak Ridge Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Hanna, S.R.

    1975-01-01

    The mechanical-draft cooling towers at the Oak Ridge Gaseous Diffusion Plant dissipate about 2000 MW of heat. Downwash occurs about 40 percent of the time, when wind speeds exceed about 3 m/sec. An elevated cloud forms about 10 percent of the time. The length of the visible plume, which is typically 100 or 200 m, is satisfactorily modeled if it is assumed that the plumes from all the cells in a cooling-tower bank combine. The calculation of fog concentration is complicated by the fact that the moisture is not inert but is taking part in the energy exchanges of a thermodynamic system. Calculations of drift deposition agree fairly well with observations

  3. Extending wind turbine operational conditions; a comparison of set point adaptation and LQG individual pitch control for highly turbulent wind

    International Nuclear Information System (INIS)

    Engels, W P; Subhani, S; Zafar, H; Savenije, F

    2014-01-01

    Extreme wind conditions can cause excessive loading on the turbine. This not only results in higher design loads, but when these conditions occur in practice, will also result in higher maintenance cost. Although there are already effective methods of dealing with gusts, other extreme conditions should also be examined. More specifically, extreme turbulence conditions (e.g. those specified by design load case 1.3 in IEC61400-1 ed. 3) require special attention as they can lead to design-driving extreme loads on blades, tower and other wind turbine components. This paper examines two methods to deal with extreme loads in a case of extreme turbulent wind. One method is derating the turbine, the other method is an individual pitch control (IPC) algorithm. Derating of the turbine can be achieved in two ways, one is changing the rated torque, the other is changing the rated rotor speed. The effect of these methods on fatigue loads and extreme loads is examined. Non-linear aero-elastic simulations using Phatas, show that reducing the rated rotor speed is far more effective at reducing the loads than reducing torque. Then, the IPC algorithm is proposed. This algorithm is a linear quadratic Gaussian (LQG) controller based on a time invariant model, defined in the fixed reference frame that includes the first tower and blade modes. Because this method takes the dynamics of the system into account more than conventional IPC control, it is expected that these loads dealt with more effectively, when they are particularly relevant. It is expected that in extreme turbulent the blade and tower dynamics are indeed more relevant. The effect of this algorithm on fatigue loads and pitch effort is examined and compared with the fatigue loads and pitch effort of reference IPC. Finally, the methods are compared in non-linear aero-elastic simulations with extreme turbulent wind

  4. Fiscal 1974 Sunshine Project result report. R and D on solar heat power generation system (R and D on tower solar collection system); 1974 nendo taiyonetsu hatsuden system no kenkyu kaihatsu seika hokokusho. Tower shuko hoshiki system no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1975-05-29

    This report summarizes the fiscal 1974 research result on the solar heat power generation system with a tower light collection system. This system receives solar radiation energy by reflector group, and concentrates solar energy reflected by each reflector on the heat absorber mounted on the top of the tower. A ratio of the whole reflector group area to the receiving area of the heat absorber is called a concentration factor. The heat absorber converts concentrated dense radiation energy to thermal energy, and transfers heated thermal medium to the bottom of the tower to supply solar heat to a thermal plant after appropriate treatment. Based on the above basic idea, study was made on the total system and each subsystem, and some problems on component equipment and materials were extracted. After solving these problems and improving the whole system accuracy, these results are put to practical use for design and operation of an actual pilot plant. The main research items are as follows: feasibility study, simulation, element study, preparation of a 10kWT test equipment, and planning of a 1,000kW class pilot plant. (NEDO)

  5. Semi-active control of monopile offshore wind turbines under multi-hazards

    Science.gov (United States)

    Sun, C.

    2018-01-01

    The present paper studies the control of monopile offshore wind turbines subjected to multi-hazards consisting of wind, wave and earthquake. A Semi-active tuned mass damper (STMD) with tunable natural frequency and damping ratio is introduced to control the dynamic response. A new fully coupled analytical model of the monopile offshore wind turbine with an STMD is established. The aerodynamic, hydrodynamic and seismic loading models are derived. Soil effects and damage are considered. The National Renewable Energy Lab monopile 5 MW baseline wind turbine model is employed to examine the performance of the STMD. A passive tuned mass damper (TMD) is utilized for comparison. Through numerical simulation, it is found that before damage occurs, the wind and wave induced response is more dominant than the earthquake induced response. With damage presence in the tower and the foundation, the nacelle and the tower response is increased dramatically and the natural frequency is decreased considerably. As a result, the passive TMD with fixed parameters becomes off-tuned and loses its effectiveness. In comparison, the STMD retuned in real-time demonstrates consistent effectiveness in controlling the dynamic response of the monopile offshore wind turbines under multi-hazards and damage with a smaller stroke.

  6. Coastal Land Air Sea Interaction: "the" beach towers

    Science.gov (United States)

    MacMahan, J. H.; Koscinski, J. S.; Ortiz-Suslow, D. G.; Haus, B. K.; Thornton, E. B.

    2016-12-01

    As part of the Coastal Land Air Sea Interaction (CLASI) experiment, an alongshore array of 6-m high towers instrumented with ultrasonic 3D anemometers and temperature-relative humidity sensors were deployed at five sandy beaches near the high-tide line in Monterey Bay, CA, in May-June 2016. A cross-shore array of towers was also deployed from within the active surfzone to the toe of the dune at one beach. In addition, waves and ocean temperature were obtained along the 10m isobath for each beach. The dissipative surfzone was O(80m) wide. The wave energy varies among the beaches owing to sheltering and refraction by the Monterey Canyon and headlands. The tides are semi-diurnal mixed, meso-tidal with a maximum tidal range of 2m. This results in a variable beach width from the tower to the tidal line. Footprint analysis for estimating the source region for the turbulent momentum fluxes, suggests that the observations represent three scenarios described as primarily ocean, mixed beach and ocean, and primarily beach. The direct-estimate of the atmospheric stability by the sonic anemometer suggest that all of the beaches are mostly unstable except for a few occurrences in the evening during low wind conditions. The onshore neutral drag coefficient (Cd) estimated at 10m heights is 3-5 times larger than open ocean estimates. Minimal variability was found in Cd based on the footprint analysis. Beach-specific spatial variability in Cd was found related to atmospheric stability and wave energy.

  7. Wind Generation Feasibility Study for Sac & Fox Tribe of the Mississippi in Iowa (Meskwaki Nation)

    Energy Technology Data Exchange (ETDEWEB)

    Lasley, Larry C. [Sac & Fox Tribe of the Mississippi in Iowa

    2013-03-19

    1.2 Overview The Meskwaki Nation will obtain an anemometer tower. Install the tower at the site that has been pre-qualified as the site most likely to produce maximum electric power from the wind. It will collect meteorological data from the tower's sensors for a one year period, as required for due diligence to identify the site as appropriate for the installation of a wind turbine to provide electric power for the community. Have the collected data analyzed by a meteorologist and a professionally certified wind engineer to produce the reports of expected power generation at the site, for the specific wind turbine(s) under consideration for installation. 1.2.1 Goals of the Tribe The feasibility study reports, including technical and business analyses will be used to obtain contracts and financing required to develop and implement a wind turbine project on the Meskwaki Settlement. Our goal is to produce two (2) mega watts of power and to reduce the cost for electricity currently being paid by the Meskwaki Casino. 1.2.2 Project Objectives Meet the energy needs of the community with clean energy. Bring renewable energy to the settlement in a responsible, affordable manner. Maximize both the economic and the spiritual benefits to the tribe from energy independence. Integrate the Tribe's energy policies with its economic development goals. Contribute to achieving the Tribe's long-term goals of self-determination and sovereignty. 1.2.3 Project Location The precise location proposed for the tower is at the following coordinates: 92 Degrees, 38 Minutes, 46.008 Seconds West Longitude 41 Degrees, 59 Minutes, 45.311 Seconds North Latitude. A circle of radius 50.64 meters, enclosing and area of 1.98 acres in PLSS Township T83N, Range R15W, in Iowa. In relative directions, the site is 1,650 feet due west of the intersection of Highway 30 and 305th Street in Tama, Iowa, as approached from the direction of Toledo, Iowa. It is bounded on the north by Highway 30 and

  8. The Cryogenic Dark Matter Search: First 5-Tower Data and Improved Understanding of Ionization Collection

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Catherine N. [Case Western Reserve Univ., Cleveland, OH (United States)

    2010-01-01

    The Cryogenic Dark Matter Search (CDMS) is searching for Weakly Interacting Massive Particles (WIMPs) with cryogenic particle detectors. These detectors have the ability to discriminate between nuclear recoil candidate and electron recoil background events by collecting both phonon and ionization energy from recoils in the detector crystals. The CDMS-II experiment has completed analysis of the first data runs with 30 semiconductor detectors at the Soudan Underground Laboratory, resulting in a world leading WIMP-nucleon spin-independent cross section limit for WIMP masses above 44 GeV/c2. As CDMS aims to achieve greater WIMP sensitivity, it is necessary to increase the detector mass and discrimination between signal and background events. Incomplete ionization collection results in the largest background in the CDMS detectors as this causes electron recoil background interactions to appear as false candidate events. Two primary causes of incomplete ionization collection are surface and bulk trapping. Recent work has been focused on reducing surface trapping through the modification of fabrication methods for future detectors. Analyzing data taken with test devices has shown that hydrogen passivation of the amorphous silicon blocking layer worsens surface trapping. Additional data has shown that the iron-ion implantation used to lower the critical temperature of the tungsten transition-edge sensors causes a degradation of the ionization collection. Using selective implantation on future detectors may improve ionization collection for events near the phonon side detector surface. Bulk trapping is minimized by neutralizing ionized lattice impurities. Detector investigations at testing facilities and in situ at the experimental site have provided methods to optimize the neutralization process and monitor running conditions to maintain full ionization collection. This work details my contribution to the 5-tower data taking, monitoring, and analysis effort as

  9. H∞ Based Control for Load Mitigation in Wind Turbines

    Directory of Open Access Journals (Sweden)

    Aron Pujana-Arrese

    2012-04-01

    Full Text Available This article demonstrates a strategy to design multivariable and multi-objective controllers based on the H∞ norm reduction applied to a wind turbine. The wind turbine model has been developed in the GH Bladed software and it is based on a 5 MW wind turbine defined in the Upwind European project. The designed control strategy works in the above rated power production zone and performs generator speed control and load reduction on the drive train and tower. In order to do this, two robust H∞ MISO (Multi-Input Single-Output controllers have been developed. These controllers generate collective pitch angle and generator torque set-point values to achieve the imposed control objectives. Linear models obtained in GH Bladed 4.0 are used, but the control design methodology can be used with linear models obtained from any other modelling package. Controllers are designed by setting out a mixed sensitivity problem, where some notch filters are also included in the controller dynamics. The obtained H∞ controllers have been validated in GH Bladed and an exhaustive analysis has been carried out to calculate fatigue load reduction on wind turbine components, as well as to analyze load mitigation in some extreme cases. The analysis compares the proposed control strategy based on H∞ controllers to a baseline control strategy designed using the classical control methods implemented on the present wind turbines.

  10. Individual pitch control of NREL 5MW wind turbine blade for load reduction

    International Nuclear Information System (INIS)

    La, Yo Han; Nam, Yoon Su; Hoon, Son Jae

    2012-01-01

    As the size of a wind turbine increases, the rotor diameter increases. Rotor blades experience mechanical loads caused by the wind shear and the tower shadow effect. These mechanical loads reduce the life of the wind turbine. Therefore, with increasing size of the wind turbine, wind turbine control system design for the mitigation of mechanical loads is important. In this study, Individual Pitch Control in introduced for reducing the mechanical loads of rotor blades, and a simulation for IPC performance verification is discussed

  11. Reduction of fatigue loads on jacket substructure through blade design optimization for multimegawatt wind turbines at 50 m water depths

    DEFF Research Database (Denmark)

    NJOMO WANDJI, Wilfried; Pavese, Christian; Natarajan, Anand

    2016-01-01

    This paper addresses the reduction of the fore-aft damage equivalent moment at the tower base for multi-megawatt offshore wind turbines mounted on jacket type substructures at 50 m water depths. The study investigates blade design optimization of a reference 10 MW wind turbine under standard wind...... conditions of onshore sites. The blade geometry and structure is optimized to yield a design that minimizes tower base fatigue loads without significant loss of power production compared to that of the reference setup. The resulting blade design is then mounted on a turbine supported by a jacket and placed...

  12. You're a What?: Tower Technician

    Science.gov (United States)

    Vilorio, Dennis

    2012-01-01

    In this article, the author talks about the role and functions of a tower technician. A tower technician climbs up the face of telecommunications towers to remove, install, test, maintain, and repair a variety of equipment--from antennas to light bulbs. Tower technicians also build shelters and radiofrequency shields for electronic equipment, lay…

  13. Prototype bucket foundation for wind turbines

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten

    The first full scale prototype bucket foundation for wind turbines has been installed in October 2002 at Aalborg University offshore test facility in Frederikshavn, Denmark. The suction caisson and the wind turbine have been equipped with an online monitoring system, consisting of 15 accelerometers...... and a real-time data-acquisition system. The report concerns the in service performance of the wind turbine, with focus on estimation of the natural frequencies of the structure/foundation. The natural frequencies are initially estimated by means of experimental Output-only Modal analysis. The experimental...... estimates are then compared with numerical simulations of the suction caisson foundation and the wind turbine. The numerical model consists of a finite element section for the wind turbine tower and nacelle. The soil-structure interaction of the soil-foundation section is modelled by lumped-parameter models...

  14. Cooling Tower Losses in Industry

    OpenAIRE

    Barhm Mohamad

    2017-01-01

    Cooling towers are a very important part of many chemical plants. The primary task of a cooling tower is to reject heat into the atmosphere. They represent a relatively inexpensive and dependable means of removing low-grade heat from cooling water. The make-up water source is used to replenish water lost to evaporation. Hot water from heat exchangers is sent to the cooling tower. The water exits the cooling tower and is sent back to the exchangers or to other units for further cooling.

  15. Alkaline approach to treating cooling towers for control of Legionella pneumophila

    Energy Technology Data Exchange (ETDEWEB)

    States, S.J.; Conley, L.F.; Towner, S.G.; Wolford, R.S.; Stephenson, T.E.; McNamara, M.; Wadowsky, R.M.; Yee, R.B.

    1987-08-01

    Earlier field and laboratory studies have shown that Legionella species survive and multiply in the pH range 5.5 to 9.2. Additionally, the technical feasibility of operating cooling towers at elevated alkalinities and pH has previously been documented by published guidelines. The guidelines indicate that these conditions facilitate corrosion control and favor chlorine persistence which enhances the effectiveness of continuous chlorination in biofouling control. This information suggest that control of Legionella species in cooling towers can be accomplished by operating the towers under alkaline conditions. To test this possibility, we collected water samples over a period of months from a hospital cooling tower. The samples were analyzed for a variety of chemical parameters. Subsamples were pasteurized and inoculated with non-agar-passaged Legionella pneumophila which had been maintained in tap water. Correlation of subsequent Legionella growth with corresponding pH and alkalinity values revealed statistically significant inverse associations. These data support the hypothesis that operating cooling towers outside of the optimal conditions for Legionella growth (e.g., at elevated alkalinities and a pH greater than 9) may be a useful approach to controlling growth in this habitat.

  16. A Comparison of Wind Flow Models for Wind Resource Assessment in Wind Energy Applications

    Directory of Open Access Journals (Sweden)

    Mathieu Landry

    2012-10-01

    Full Text Available The objective of this work was to assess the accuracy of various coupled mesoscale-microscale wind flow modeling methodologies for wind energy applications. This is achieved by examining and comparing mean wind speeds from several wind flow modeling methodologies with observational measurements from several 50 m met towers distributed across the study area. At the mesoscale level, with a 5 km resolution, two scenarios are examined based on the Mesoscale Compressible Community Model (MC2 model: the Canadian Wind Energy Atlas (CWEA scenario, which is based on standard input data, and the CWEA High Definition (CWEAHD scenario where high resolution land cover input data is used. A downscaling of the obtained mesoscale wind climate to the microscale level is then performed, where two linear microscale models, i.e., MsMicro and the Wind Atlas Analysis and Application Program (WAsP, are evaluated following three downscaling scenarios: CWEA-WAsP, CWEA-MsMicro and CWEAHD-MsMicro. Results show that, for the territory studied, with a modeling approach based on the MC2 and MsMicro models, also known as Wind Energy Simulation Toolkit (WEST, the use of high resolution land cover and topography data at the mesoscale level helps reduce modeling errors for both the mesoscale and microscale models, albeit only marginally. At the microscale level, results show that the MC2-WAsP modeling approach gave substantially better results than both MC2 and MsMicro modeling approaches due to tweaked meso-micro coupling.

  17. Variation in agricultural CO2 fluxes during the growing season, collected from more than ten eddy covariance towers in the Mississippi Delta Region

    Science.gov (United States)

    Runkle, B.; Suvocarev, K.; Reba, M. L.; Novick, K. A.; White, P.; Anapalli, S.; Locke, M. A.; Rigby, J.; Bhattacharjee, J.

    2016-12-01

    Agriculture is unique as an anthropogenic activity that plays both a large role in carbon and water cycling and whose management activities provide a key opportunity for responses to climate change. It is therefore especially crucial to bring field observations into the modeling community, test remote sensing products, encourage policy debate, and enable carbon offsets markets that generate revenue and fund climate-smart activities. The accurate measurement of agricultural CO2 exchange - both primary productivity and ecosystem respiration - in concert with evapotranspiration provides crucial information on agro-ecosystem functioning and improves our predictive capacity for estimating the impacts of climate change. In this study we report field measurements from more than 10 eddy covariance towers in the Lower Mississippi River Basin taken during the summer months of 2016. Many towers, some recently deployed, are being aggregated into a regional network known as Delta-Flux, which will ultimately include 15-20 towers by 2017. Set in and around the Mississippi Delta Region within Louisiana, Arkansas, and Mississippi, the network will collect flux, micrometeorological, and crop yield data in order to construct estimates of regional CO2 exchange. These time-series data are gap-filled using statistical and process-based models to generate estimates of summer CO2 flux. The tower network is comprised of sites representing widespread agriculture production, including rice, cotton, corn, soybean, and sugarcane; intensively managed pine forest; and bottomland hardwood forest. Unique experimental production practices are represented in the network and include restricted water use, bioenergy, and by-product utilization. Several towers compose multi-field sites testing innovative irrigation or management practices. Current mapping of agricultural carbon exchange - based on land cover layers and fixed crop emission factors - suggests an unconstrained carbon flux estimate in this

  18. Wind emergency response system

    International Nuclear Information System (INIS)

    Garrett, A.J.; Buckner, M.R.; Mueller, R.A.

    1981-01-01

    The WIND system is an automated emergency response system for real-time predictions of the consequences of liquid and airborne releases from SRP. The system consists of a minicomputer and associated peripherals necessary for acquisition and handling of large amounts of meteorological data from a local tower network and the National Weather Service. The minicomputer uses these data and several predictive models to assess the impact of accidental releases. The system is fast and easy to use, and output is displayed both in tabular form and as trajectory map plots for quick interpretation. The rapid response capabilities of the WIND system have been demonstrated in support of SRP operations

  19. Catching the Wind in a Bottle: Collection Development for Wind Energy Technology Programs at Universities and Colleges

    Science.gov (United States)

    Johnson-Renvall, Poppy

    2009-01-01

    This article aims to assist information professionals in developing a resource collection that serves Wind Energy students in academic settings. Traditional as well as Internet resources should be utilized in order to meet the needs of this unique student population.

  20. Drop Tower Physics

    Science.gov (United States)

    Dittrich, William A.

    2014-01-01

    The drop towers of yesteryear were used to make lead shot for muskets, as described in "The Physics Teacher" in April 2012. However, modern drop towers are essentially elevators designed so that the cable can "break" on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at…

  1. Effects of normal and extreme turbulence spectral parameters on wind turbine loads

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov; Natarajan, Anand; Mann, Jakob

    2017-01-01

    the recommended values in the IEC 61400-1 Ed.3 that is used for wind turbine design. The present paper investigates the impact of Mann turbulence model parameter variations on the design loads envelope for 5 MW and 10 MW reference wind turbines. Specific focus is made on the blade root loads, tower top moments...... of design loads is investigated with a focus on the commonly used Mann turbulence model. Quantification of the Mann model parameters is made through wind measurements acquired from the Høvsøre site. The parameters of the Mann model fitted to site specific observations can differ significantly from...... and tower base loads under normal turbulence and extreme turbulence, whereby the change in operating extreme and fatigue design loads obtained through turbulence model parameter variations is compared with corresponding variations obtained from random seeds of turbulence. The investigations quantify...

  2. Aeroelastic Optimization of MW Wind Turbines

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig; Zahle, Frederik

    This report contains the results from the Energy Development and Demonstration Project “Aeroelastic Optimization of MW wind turbine” (AeroOpt). The project has had the following five Work Packages: 1. Geometric non-linear, anisotropic beamelement forHAWC2 2. Closed-loop eigenvalue analysis...... of controlled wind turbines 3. Resonant wave excitation of lateral tower bending modes 4. Development of next generation aerodynamic design tools 5. Advanced design and verification of airfoils The purposes of these Work Packages are briefly described in the Preface and a summary of the results are given...

  3. Wind flow around met masts

    Energy Technology Data Exchange (ETDEWEB)

    Heraud, P.; Masson, C.; Tusch, M. [Garrad Hassan Canada Inc., Ottawa, ON (Canada)

    2010-07-01

    This PowerPoint presentation discussed the impacts of meteorological masts on the measurement of wind resources. Two types of meteorological masts are used in wind power applications, namely lattice, and tubular masts. Anemometer accuracy can be impacted by the logger as well as by the instrumentation layout. The International Electrochemical Commission (IEC) recommends that anemometers are placed at a 45 degree angle from pre-dominant winds. However, the impact of turbulent flow around meteorological masts is poorly understood. The numerical model developed in the study included mass and momentum conservation models for tubular and lattice towers. Distortion level recommendations were presented. The study showed that distortion depends on the layout, and that IEC recommendations for instrumentation layouts need to be revised. tabs., figs.

  4. Models for wind turbines - a collection

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.C.; Hansen, M.H. (eds.); Baumgart, A.

    2002-02-01

    This report is a collection of notes which were intended to be short communications. Main target of the work presented is to supply new approaches to stability investigations of wind turbines. The authors opinion is that an efficient, systematic stability analysis can not be performed for large systems of differential equations (i.e. the order of the differential equations > 100), because numerical 'effects' in the solution of the equations of motion as initial value problem, eigenvalue problem or whatsoever become predominant. It is therefore necessary to find models which are reduced to the elementary coordinates but which can still describe the physical processes under consideration with sufficiently good accuracy. Such models are presented. (au)

  5. The effect of the Sep wind park near Oosterbierum, Friesland, The Netherlands, on birds

    International Nuclear Information System (INIS)

    Winkelman, J.E.

    1992-01-01

    The title study concerns the period 1984-1991. The wind park consists of 18 three-bladed 300 kW horizontal axis wind turbines of 35 meters height, and a rotor diameter of 30 meters, seven meteorological towers, and three cluster and control buildings. Aspects studied included disturbance of breeding, resting or feeding, and migrating birds, behavior of birds approaching the wind turbines during the day and night, and bird victims due to collision with the wind turbines and the meteorological towers. In this report attention is paid to the disturbance of the bird's biotope. The results show that four species of grassland birds, breeding in the park, were hardly disturbed by the wind turbines. For feeding and resting birds, however, disturbance effects were noted, even at a distance of 500 meters from the outside wind turbine array. The present number of bird species reduced 60-95%, dependent on the species, after the wind park was put into operation. Also the behavior of migrating birds was influenced by the wind park, showed in clustering of groups or avoiding the wind park, sometimes up to 67% of the birds did so. It is therefore recommended not to implement new wind parks in important bird migration and bird feeding or bird resting areas. Bird popular areas, however, are mostly windy areas. 15 figs., 25 tabs., 56 app., 128 refs

  6. Wind scatterometry with improved ambiguity selection and rain modeling

    Science.gov (United States)

    Draper, David Willis

    Although generally accurate, the quality of SeaWinds on QuikSCAT scatterometer ocean vector winds is compromised by certain natural phenomena and retrieval algorithm limitations. This dissertation addresses three main contributors to scatterometer estimate error: poor ambiguity selection, estimate uncertainty at low wind speeds, and rain corruption. A quality assurance (QA) analysis performed on SeaWinds data suggests that about 5% of SeaWinds data contain ambiguity selection errors and that scatterometer estimation error is correlated with low wind speeds and rain events. Ambiguity selection errors are partly due to the "nudging" step (initialization from outside data). A sophisticated new non-nudging ambiguity selection approach produces generally more consistent wind than the nudging method in moderate wind conditions. The non-nudging method selects 93% of the same ambiguities as the nudged data, validating both techniques, and indicating that ambiguity selection can be accomplished without nudging. Variability at low wind speeds is analyzed using tower-mounted scatterometer data. According to theory, below a threshold wind speed, the wind fails to generate the surface roughness necessary for wind measurement. A simple analysis suggests the existence of the threshold in much of the tower-mounted scatterometer data. However, the backscatter does not "go to zero" beneath the threshold in an uncontrolled environment as theory suggests, but rather has a mean drop and higher variability below the threshold. Rain is the largest weather-related contributor to scatterometer error, affecting approximately 4% to 10% of SeaWinds data. A simple model formed via comparison of co-located TRMM PR and SeaWinds measurements characterizes the average effect of rain on SeaWinds backscatter. The model is generally accurate to within 3 dB over the tropics. The rain/wind backscatter model is used to simultaneously retrieve wind and rain from SeaWinds measurements. The simultaneous

  7. Fire ants perpetually rebuild sinking towers

    Science.gov (United States)

    Phonekeo, Sulisay; Mlot, Nathan; Monaenkova, Daria; Hu, David L.; Tovey, Craig

    2017-07-01

    In the aftermath of a flood, fire ants, Solenopsis invicta, cluster into temporary encampments. The encampments can contain hundreds of thousands of ants and reach over 30 ants high. How do ants build such tall structures without being crushed? In this combined experimental and theoretical study, we investigate the shape and rate of construction of ant towers around a central support. The towers are bell shaped, consistent with towers of constant strength such as the Eiffel tower, where each element bears an equal load. However, unlike the Eiffel tower, the ant tower is built through a process of trial and error, whereby failed portions avalanche until the final shape emerges. High-speed and novel X-ray videography reveal that the tower constantly sinks and is rebuilt, reminiscent of large multicellular systems such as human skin. We combine the behavioural rules that produce rafts on water with measurements of adhesion and attachment strength to model the rate of growth of the tower. The model correctly predicts that the growth rate decreases as the support diameter increases. This work may inspire the design of synthetic swarms capable of building in vertical layers.

  8. Use of Small-Scale Wind Energy to Power Cellular Communication Equipment

    Directory of Open Access Journals (Sweden)

    B. Plourde

    2011-12-01

    Full Text Available The recent increase in cellular communication coverage and usage has been remarkable. The increase has occurred throughout the globe, in both developed and developing regions. In fact, in some regions of the world, land-line communications are being avoided altogether as countries move into primarily mobile communication technologies. In order for cellular communication to function adequately, communication towers must be built with sufficient density to provide coverage. These towers have electrical requirements which are often not met with grid-based power. This study presents a novel design of a wind turbine which is designed to be positioned atop existing communication towers in order to provide local power for the tower. These turbines have vertical axes of rotation and other features which suit them for this highly specialized application. The study carried out here shows that these turbines are able to provide the required electrical power to fully satisfy the communication-tower electronics.

  9. The influence of atmospheric conditions on the cooling tower plume of nuclear power station; Uticaj atmosferskih uslova na perjanicu rashladnih tornjeva nuklearne elektrane

    Energy Technology Data Exchange (ETDEWEB)

    Vehauc, A [Boris Kidric Institute of nuclear sciences, Vinca, Belgrade (Yugoslavia)

    1978-07-01

    The paper deals with the effect of atmospheric conditions - relative humidity, wind velocity, temperature and temperature gradient on the visible plume. For estimating cooling tower plumes, used was made of verified mathematical model. (author)

  10. Effects of Yaw Error on Wind Turbine Running Characteristics Based on the Equivalent Wind Speed Model

    Directory of Open Access Journals (Sweden)

    Shuting Wan

    2015-06-01

    Full Text Available Natural wind is stochastic, being characterized by its speed and direction which change randomly and frequently. Because of the certain lag in control systems and the yaw body itself, wind turbines cannot be accurately aligned toward the wind direction when the wind speed and wind direction change frequently. Thus, wind turbines often suffer from a series of engineering issues during operation, including frequent yaw, vibration overruns and downtime. This paper aims to study the effects of yaw error on wind turbine running characteristics at different wind speeds and control stages by establishing a wind turbine model, yaw error model and the equivalent wind speed model that includes the wind shear and tower shadow effects. Formulas for the relevant effect coefficients Tc, Sc and Pc were derived. The simulation results indicate that the effects of the aerodynamic torque, rotor speed and power output due to yaw error at different running stages are different and that the effect rules for each coefficient are not identical when the yaw error varies. These results may provide theoretical support for optimizing the yaw control strategies for each stage to increase the running stability of wind turbines and the utilization rate of wind energy.

  11. Optimal Risk-Based Inspection Planning for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Rangel-Ramirez, Jose G.; Sørensen, John Dalsgaard

    2008-01-01

    , inspection and maintenance activities are developed. This paper considers aspects of inspection and maintenance planning of fatigue prone details in jacket and tripod types of wind turbine support structures. Based oil risk-based inspection planning methods used for oil & gas installations, a framework......Wind turbines for electricity production have increased significantly the last years both in production capability and size. This development is expected to continue also in the coining years. The Support structure for offshore wind turbines is typically a steel structure consisting of a tower...... for optimal inspection and maintenance planning of offshore wind turbines is presented. Special aspects for offshore wind turbines are considered: usually the wind loading are dominating the wave loading, wake effects in wind farms are important and the reliability level is typically significantly lower than...

  12. Consequences of variations in spatial turbulence characteristics for fatigue life time of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.C.

    1998-09-01

    The fatigue loading of turbines situated in complex terrain is investigated in order to determine the crucial parameters in the spatial structure of the turbulence in such situations. The parameter study is performed by means of numerical calculations, and it embraces three different wind turbine types, representing a pitch controlled concept, a stall controlled concept, and a stall controlled concept with an extremely flexible tower. For each of the turbine concepts, the fatigue load sensibility to the selected turbulence characteristics are investigated for three different mean wind speeds at hub height. The selected mean wind speeds represent the linear-, the stall-, and the post stall aerodynamic region for the stall controlled turbines and analogously the unregulated-, the partly regulated-, and the fully regulated regime for the pitch controlled turbine. Denoting the turbulence component in the mean wind direction by u, the lateral turbulence component by v, and the vertical turbulence component by w, the selected turbulence characteristics comprise the u-turbulence length scale, the ratio between the v- and w-turbulence intensities and the u-turbulence intensity, the uu-coherence decay factor, and finally the u-v and u-w cross-correlations. The turbulence length scale in the mean wind direction gives rise to significant modification of the fatigue loading on all the investigated wind turbine concepts, but for the other selected parameter variations, large individual differences exists between the turbines. With respect to sensitivity to the performed parameter variations, the Vestas V39 wind turbine is the most robust of the investigated turbines. The Nordtank 500/37 turbine, equipped with the (artificial) soft tower, is by far the most sensitive of the investigated turbine concepts - also much more sensitive than the conventional Nordtank 500/37 turbine equipped with a traditional tower. (au) 2 tabs., 43 ills., 7 refs.

  13. A GIS wind resource map with tabular printout of monthly and annual wind speeds for 2,000 towns in Iowa

    Energy Technology Data Exchange (ETDEWEB)

    Brower, M.C. [Brower & Company, Andover, MA (United States); Factor, T. [Iowa Wind Energy Institute, Fairfield, IA (United States)

    1997-12-31

    The Iowa Wind Energy Institute, under a grant from the Iowa Energy Center, undertook in 1994 to map wind resources in Iowa. Fifty-meter met towers were erected at 13 locations across the state deemed promising for utility-scale wind farm development. Two years of summarized wind speed, direction, and temperature data were used to create wind resource maps incorporating effects of elevation, relative exposure, terrain roughness, and ground cover. Maps were produced predicting long-term mean monthly and annual wind speeds on a one-kilometer grid. The estimated absolute standard error in the predicted annual average wind speeds at unobstructed locations is 9 percent. The relative standard error between points on the annual map is estimated to be 3 percent. These maps and tabular data for 2,000 cities and towns in Iowa are now available on the Iowa Energy Center`s web site (http.//www.energy.iastate.edu).

  14. Cooling tower

    Energy Technology Data Exchange (ETDEWEB)

    Norbaeck, P; Heneby, H

    1976-01-22

    Cooling towers to be transported on road vehicles as a unit are not allowed to exceed certain dimensions. In order to improve the efficiency of such a cooling tower (of cross-flow design and box-type body) with given dimensions, it is proposed to arrange at least one of the scrubbing bodies displaceable within a module or box. Then it can be moved out of the casing into working position, thereby increasing the front surface available for the inlet of air (and with it the efficiency) by nearly a factor of two.

  15. Wind Turbine Loads Induced by Terrain and Wakes: An Experimental Study through Vibration Analysis and Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    Francesco Castellani

    2017-11-01

    Full Text Available A wind turbine is a very well-known archetype of energy conversion system working at non-stationary regimes. Despite this, a deep mechanical comprehension of wind turbines operating in complicated conditions is still challenging, especially as regards the analysis of experimental data. In particular, wind turbines in complex terrain represent a very valuable testing ground because of the possible combination of wake effects among nearby turbines and flow accelerations caused by the terrain morphology. For these reasons, in this work, a cluster of four full-scale wind turbines from a very complex site is studied. The object of investigation is vibrations, at the level of the structure (tower and drive-train. Data collected by the on-board condition monitoring system are analyzed and interpreted in light of the knowledge of wind conditions and operating parameters collected by the Supervisory Control And Data Acquisition (SCADA. A free flow Computational Fluid Dynamics (CFD simulation is also performed, and it allows one to better interpret the vibration analysis. The main outcome is the interpretation of how wakes and flow turbulences appear in the vibration signals, both at the structural level and at the drive-train level. Therefore, this wind to gear approach builds a connection between flow phenomena and mechanical phenomena in the form of vibrations, representing a precious tool for assessing loads in different working conditions.

  16. Field Testing of Feedforward Collective Pitch Control on the CART2 Using a Nacelle-Based Lidar Scanner

    International Nuclear Information System (INIS)

    Schlipf, David; Haizmann, Florian; Hofsäß, Martin; Cheng, Po Wen; Fleming, Paul; Scholbrock, Andrew; Wright, Alan

    2014-01-01

    This work presents the results from a field test of LIDAR assisted collective pitch control using a scanning LIDAR device installed on the nacelle of a mid-scale research turbine. A nonlinear feedforward controller is extended by an adaptive filter to remove all uncorrelated frequencies of the wind speed measurement to avoid unnecessary control action. Positive effects on the rotor speed regulation as well as on tower, blade and shaft loads have been observed in the case that the previous measured correlation and timing between the wind preview and the turbine reaction are accomplish. The feedforward controller had negative impact, when the LIDAR measurement was disturbed by obstacles in front of the turbine. This work proves, that LIDAR is valuable tool for wind turbine control not only in simulations but also under real conditions. Furthermore, the paper shows that further understanding of the relationship between the wind measurement and the turbine reaction is crucial to improve LIDAR assisted control of wind turbines

  17. Field Testing of Feedforward Collective Pitch Control on the CART2 Using a Nacelle-Based Lidar Scanner

    Science.gov (United States)

    Schlipf, David; Fleming, Paul; Haizmann, Florian; Scholbrock, Andrew; Hofsäß, Martin; Wright, Alan; Cheng, Po Wen

    2014-12-01

    This work presents the results from a field test of LIDAR assisted collective pitch control using a scanning LIDAR device installed on the nacelle of a mid-scale research turbine. A nonlinear feedforward controller is extended by an adaptive filter to remove all uncorrelated frequencies of the wind speed measurement to avoid unnecessary control action. Positive effects on the rotor speed regulation as well as on tower, blade and shaft loads have been observed in the case that the previous measured correlation and timing between the wind preview and the turbine reaction are accomplish. The feedforward controller had negative impact, when the LIDAR measurement was disturbed by obstacles in front of the turbine. This work proves, that LIDAR is valuable tool for wind turbine control not only in simulations but also under real conditions. Furthermore, the paper shows that further understanding of the relationship between the wind measurement and the turbine reaction is crucial to improve LIDAR assisted control of wind turbines.

  18. Errors in second moments estimated from monostatic Doppler sodar winds. II. Application to field measurements

    DEFF Research Database (Denmark)

    Gaynor, J. E.; Kristensen, Leif

    1986-01-01

    Observatory tower. The approximate magnitude of the error due to spatial and temporal pulse volume separation is presented as a function of mean wind angle relative to the sodar configuration and for several antenna pulsing orders. Sodar-derived standard deviations of the lateral wind component, before...

  19. Advanced Offshore Wind Turbine/Foundation Concept for the Great Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Afjeh, Abdollah A. [Univ. of Toledo, OH (United States); Windpower, Nautica [Nautica Windpower, Olmsted Falls, OH (United States); Marrone, Joseph [OCC COWI, Vancouver (Canada); Wagner, Thomas [Nautica Windpower, Olmsted Falls, OH (United States)

    2013-08-29

    This project investigated a conceptual 2-bladed rotor wind turbine design and assessed its feasibility for installation in the Great Lakes. The levelized cost of energy was used for this purpose. A location in Lake Erie near the coast of Cleveland, Ohio was selected as the application site. The loading environment was defined using wind and wave data collected at a weather station in Lake Erie near Cleveland. In addition, the probability distributions of the annual significant wave height and wind speed were determined. A model of the dependence of the above two quantities was also developed and used in the study of wind turbine system loads. Loads from ice floes and ridges were also included.The NREL 5 MW 3-bladed rotor wind turbine concept was used as the baseline design. The proposed turbine design employs variable pitch blade control with tip-brakes and a teeter mechanism. The rotor diameter, rated power and the tower dimensions were selected to closely match those of the NREL 5 MW wind turbine.A semi-floating gravity base foundation was designed for this project primarily to adapt to regional logistical constraints to transport and install the gravity base foundation. This foundation consists of, from bottom to top, a base plate, a buoyancy chamber, a taper zone, a column (with ice cone), and a service platform. A compound upward-downward ice cone was selected to secure the foundation from moving because of ice impact.The turbine loads analysis was based on International ElectroTechnical Committee (IEC) Standard 61400-1, Class III winds. The NREL software FAST was the primary computational tool used in this study to determine all design load cases. An initial set of studies of the dynamics of wind turbines using Automatic Dynamic Analysis of Mechanical Systems (ADAMS) demonstrated that FAST and ADAMS load predictions were comparable. Because of its relative simplicity and short run times, FAST was selected for this study. For ice load calculations, a method

  20. Producing Turbulent Wind Tunnel Inflows Relevant to Wind Turbines using an Active Grid

    Science.gov (United States)

    Rumple, Christopher; Welch, Matthew; Naughton, Jonathan

    2017-11-01

    The rise of industries like wind energy have provided motivation for generating realistic turbulent inflows in wind tunnels. Facilities with the ability to produce such inflows can study the interaction between the inflow turbulence and the flow of interest such as a wind turbine wake. An active grid - a system of actively driven elements - has gained increasing acceptance in turbulence research over the last 20 years. The ability to tailor the inflow turbulence quantities (e.g. turbulence intensities, integral length scale, and turbulence spectrum) is a driving reason for the growing use of active grids. An active grid with 40 independent axes located within the forward contraction of a low speed wind tunnel is used to explore the range of turbulent inflows possible using hot-wire anemometry to characterize the turbulence. Motor control algorithms (i.e. user waveform inputs) used to produce various turbulent inflows will be presented. Wind data available from meteorological towers are used to develop relevant inflows for wind turbines to demonstrate the usefulness of the active grid. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award # DE-SC0012671.

  1. Aspects of a potential impact of wind turbines on birds

    Directory of Open Access Journals (Sweden)

    Gabriel Fischer

    2005-11-01

    Full Text Available The electricity generated from renewable energy resources is an environmentally-preferred alternative to the conventionally produced electricity from fossil fuel and nuclear power plants. As the demand for a clean energy increases, the wind power generating stations are being constructed across Europe. However, concerns have been raised about the possible environmental impact of these turbines on birds. A research in this area has focused primarily on the mortality caused by birds striking turbine blades and associated wires. The disturbance to breeding, wintering or staging birds as a result of turbines has not been examined in detail. With respect to avian mortality at wind power generating stations, the greatest concern has been for raptors and migrating songbirds. The concern for raptors generally stems from the fact that many populations are small and thus even a few deaths can lead to declines. Songbirds are also considered at risk because they are known to fly into human-made structures (e.g. office towers, TV/microwave towers causing, on occasion, mass kills of thousands of individuals. While raptors and songbirds are generally at greatest risk of injury or death from turbines, the impact of such structures on all bird species should be considered on a site-by-site basis. Generally is possible to say that collisions with transmission and distribution lines, automobiles, trucks, tall building, residential house windows and lighted communication towers are more important for the avian mortality than the wind power generating stations.

  2. Wind measurements with SODAR during strong temperature inversions near the ground

    International Nuclear Information System (INIS)

    Thomas, P.; Vogt, S.

    1989-08-01

    SODAR (Sound Detection and Ranging) equipment has been increasingly used to measure vertical wind profiles with little expenditure in terms of staff, continuously over time and with a good spatial resolution. These informations serve as input variables for atmospheric transport and dispersion models, environmental monitoring of industrial facilities and, generally, for investigating a broad spectrum of meteorological phenomena. The SODAR principle has proved its suitability since long provided that the data recorded with SODAR have served to establish wind statistics valid for extended periods of time. At industrial sites potentially releasing substances prejudicial to health, e.g., chemical plants, nuclear power plants, etc., a SODAR must, moreover, be capable of measuring reliable the wind conditions also during short periods of release. This would, e.g., be important during accidental releases. Especially interesting situations for pollutant dispersion are distinct temperature inversions. It will be examined in this paper whether a SODAR is capable of measuring reliably the wind conditions also during those inversions. The selection of the situations of inversion as well as the direct intercomparison of data supplied by SODAR and conventional wind measuring instruments (anemometer and wind vane) are possible at the 200 m meteorological tower erected at the Karlsruhe Nuclear Research Center. The comparison between SODAR and the meteorological tower has shown that a SODAR is able to measure reliably the wind data also in situations characterized by strong ground-based and elevated inversions, respectively. (orig./KW) [de

  3. Cost optimization of wind turbines for large-scale offshore wind farms

    International Nuclear Information System (INIS)

    Fuglsang, P.; Thomsen, K.

    1998-02-01

    This report contains a preliminary investigation of site specific design of off-shore wind turbines for a large off-shore wind farm project at Roedsand that is currently being proposed by ELKRAFT/SEAS. The results were found using a design tool for wind turbines that involve numerical optimization and aeroelastic calculations of response. The wind climate was modeled in detail and a cost function was used to estimate costs from manufacture and installation. Cost of energy is higher for off-shore installations. A comparison of an off-shore wind farm site with a typical stand alone on-shore site showed an increase of the annual production of 28% due to the difference in wind climate. Extreme loads and blade fatigue loads were nearly identical, however,fatigue loads on other main components increased significantly. Optimizations were carried out to find the optimum overall off-shore wind turbine design. A wind turbine for the off-shore wind farm should be different compared with a stand-alone on-shore wind turbine. The overall design changed were increased swept area and rated power combined with reduced rotor speed and tower height. Cost was reduced by 12% for the final 5D/14D off-shore wind turbine from 0.306 DKr/kWh to 0.270 DKr/kWh. These figures include capital costs from manufacture and installation but not on-going costs from maintenance. These results make off-shore wind farms more competitive and comparable to the reference on-shore stand-alone wind turbine. A corresponding reduction of cost of energy could not be found for the stand alone on-shore wind turbine. Furthermore the fatigue loads on wind turbines in on-shore wind farms will increase and cost of energy will increase in favor of off-shore wind farms. (au) EFP-95; EU-JOULE-3; 21 tabs., 7 ills., 8 refs

  4. An alkaline approach to treating cooling towers for control of Legionella pneumophila.

    Science.gov (United States)

    States, S J; Conley, L F; Towner, S G; Wolford, R S; Stephenson, T E; McNamara, A M; Wadowsky, R M; Yee, R B

    1987-08-01

    Earlier field and laboratory studies have shown that Legionella species survive and multiply in the pH range 5.5 to 9.2. Additionally, the technical feasibility of operating cooling towers at elevated alkalinities and pH has previously been documented by published guidelines. The guidelines indicate that these conditions facilitate corrosion control and favor chlorine persistence which enhances the effectiveness of continuous chlorination in biofouling control. This information suggests that control of Legionella species in cooling towers can be accomplished by operating the towers under alkaline conditions. To test this possibility, we collected water samples over a period of months from a hospital cooling tower. The samples were analyzed for a variety of chemical parameters. Subsamples were pasteurized and inoculated with non-agar-passaged Legionella pneumophila which had been maintained in tap water. Correlation of subsequent Legionella growth with corresponding pH and alkalinity values revealed statistically significant inverse associations. These data support the hypothesis that operating cooling towers outside of the optimal conditions for Legionella growth (e.g., at elevated alkalinities and a pH greater than 9) may be a useful approach to controlling growth in this habitat.

  5. 1:50 Scale Testing of Three Floating Wind Turbines at MARIN and Numerical Model Validation Against Test Data

    Energy Technology Data Exchange (ETDEWEB)

    Dagher, Habib [Univ. of Maine, Orno, ME (United States); Viselli, Anthony [Univ. of Maine, Orno, ME (United States); Goupee, Andrew [Univ. of Maine, Orno, ME (United States); Allen, Christopher [Univ. of Maine, Orno, ME (United States)

    2017-08-15

    The primary goal of the basin model test program discussed herein is to properly scale and accurately capture physical data of the rigid body motions, accelerations and loads for different floating wind turbine platform technologies. The intended use for this data is for performing comparisons with predictions from various aero-hydro-servo-elastic floating wind turbine simulators for calibration and validation. Of particular interest is validating the floating offshore wind turbine simulation capabilities of NREL’s FAST open-source simulation tool. Once the validation process is complete, coupled simulators such as FAST can be used with a much greater degree of confidence in design processes for commercial development of floating offshore wind turbines. The test program subsequently described in this report was performed at MARIN (Maritime Research Institute Netherlands) in Wageningen, the Netherlands. The models considered consisted of the horizontal axis, NREL 5 MW Reference Wind Turbine (Jonkman et al., 2009) with a flexible tower affixed atop three distinct platforms: a tension leg platform (TLP), a spar-buoy modeled after the OC3 Hywind (Jonkman, 2010) and a semi-submersible. The three generic platform designs were intended to cover the spectrum of currently investigated concepts, each based on proven floating offshore structure technology. The models were tested under Froude scale wind and wave loads. The high-quality wind environments, unique to these tests, were realized in the offshore basin via a novel wind machine which exhibits negligible swirl and low turbulence intensity in the flow field. Recorded data from the floating wind turbine models included rotor torque and position, tower top and base forces and moments, mooring line tensions, six-axis platform motions and accelerations at key locations on the nacelle, tower, and platform. A large number of tests were performed ranging from simple free-decay tests to complex operating conditions with

  6. Three-dimensional Magnetohydrodynamical Simulations of the Morphology of Head–Tail Radio Galaxies Based on the Magnetic Tower Jet Model

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Zhaoming; Yuan, Feng [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Li, Hui; Li, Shengtai, E-mail: zmgan@shao.ac.cn, E-mail: fyuan@shao.ac.cn, E-mail: hli@lanl.gov, E-mail: sli@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2017-04-10

    The distinctive morphology of head–tail radio galaxies reveals strong interactions between the radio jets and their intra-cluster environment, the general consensus on the morphology origin of head–tail sources is that radio jets are bent by violent intra-cluster weather. We demonstrate in this paper that such strong interactions provide a great opportunity to study the jet properties and also the dynamics of the intra-cluster medium (ICM). By three-dimensional magnetohydrodynamical simulations, we analyze the detailed bending process of a magnetically dominated jet, based on the magnetic tower jet model. We use stratified atmospheres modulated by wind/shock to mimic the violent intra-cluster weather. Core sloshing is found to be inevitable during the wind-cluster core interaction, which induces significant shear motion and could finally drive ICM turbulence around the jet, making it difficult for the jet to survive. We perform a detailed comparison between the behavior of pure hydrodynamical jets and the magnetic tower jet and find that the jet-lobe morphology could not survive against the violent disruption in all of our pure hydrodynamical jet models. On the other hand, the head–tail morphology is well reproduced by using a magnetic tower jet model bent by wind, in which hydrodynamical instabilities are naturally suppressed and the jet could always keep its integrity under the protection of its internal magnetic fields. Finally, we also check the possibility for jet bending by shock only. We find that shock could not bend the jet significantly, and thus could not be expected to explain the observed long tails in head–tail radio galaxies.

  7. Simulation of Lightning Overvoltage Distribution on Stator Windings of Wind Turbine Generators

    Institute of Scientific and Technical Information of China (English)

    LIU Rong; LIU Xue-zhong; WANG Ying; LI Dan-dan

    2011-01-01

    This paper analyzes lightning surge on the stator windings of wind turbine generators. The path of lightning in the wind turbines was analyzed. An equivalent circuit model for megawatt direct-driven wind turbine system was developed, in which high-frequency distributed parameters of the blade conducts, tower, power cables and stator windings of generator were calculated based on finite element method, and the models of converter, grounding, loads, surge protection devices and power grid were established. The voltage distribution along stator windings, when struck by lightning with 10/350 ~ts wave form and different amplitude current between 50 kA and 200 kA, was simulated u- sing electro-magnetic transient analysis method. The simulated results show that the highest coil-to-core voltage peak appears on the last coil or near the neutral of stator windings, and the voltage distribution along the windings is non- uniform initially. The voltage drops of each coil fall from first to last coil, and the highest voltage drop appears on the first coil. The insulation damage may occur on the windings under lightning overvoltage. The surge arresters can re- strain the lightning surge in effect and protect the insulation. The coil-to-core voltage in the end of windings is nearly 19.5 kV under the 200 kA lightning current without surge arresters on the terminal of generator, but is only 2.7 kV with arresters.

  8. Weibull Wind-Speed Distribution Parameters Derived from a Combination of Wind-Lidar and Tall-Mast Measurements Over Land, Coastal and Marine Sites

    DEFF Research Database (Denmark)

    Gryning, Sven-Erik; Floors, Rogier Ralph; Peña, Alfredo

    2016-01-01

    Wind-speed observations from tall towers are used in combination with observations up to 600 m in altitude from a Doppler wind lidar to study the long-term conditions over suburban (Hamburg), rural coastal (Høvsøre) and marine (FINO3) sites. The variability in the wind field among the sites is ex...... of the vertical profile of the shape parameter fits well with observations over land, coastal regions and over the sea. An applied model for the dependence of the reversal height on the surface roughness is in good agreement with the observations over land....

  9. Cooling towers

    International Nuclear Information System (INIS)

    Korik, L.; Burger, R.

    1992-01-01

    What is the effect of 0.6C (1F) temperature rise across turbines, compressors, or evaporators? Enthalpy charts indicate for every 0.6C (1F) hotter water off the cooling tower will require an additional 2 1/2% more energy cost. Therefore, running 2.2C (4F) warmer due to substandard cooling towers could result in a 10% penalty for overcoming high heads and temperatures. If it costs $1,250,000.00 a year to operate the system, $125,000.00 is the energy penalty for hotter water. This paper investigates extra fuel costs involved in maintaining design electric production with cooling water 0.6C (1F) to 3C (5.5F) hotter than design. If design KWH cannot be maintained, paper will calculate dollar loss of saleable electricity. The presentation will conclude with examining the main causes of deficient cold water production. State-of-the-art upgrading and methodology available to retrofit existing cooling towers to optimize lower cooling water temperatures will be discussed

  10. Induced draught circular cooling tower

    International Nuclear Information System (INIS)

    Blanquet, J.C.

    1980-01-01

    Induced draught atmospheric cooling towers are described, to wit those in which the circulation is by power fans. This technique with fans grouped together in the centre enables a single tower to be used and provides an excellent integration of the steam wreath into the atmosphere. This type of cooling tower has been chosen for fitting out two 900 MW units of the Chinon power station in France [fr

  11. Frequency weighted model predictive control of wind turbine

    DEFF Research Database (Denmark)

    Klauco, Martin; Poulsen, Niels Kjølstad; Mirzaei, Mahmood

    2013-01-01

    This work is focused on applying frequency weighted model predictive control (FMPC) on three blade horizontal axis wind turbine (HAWT). A wind turbine is a very complex, non-linear system influenced by a stochastic wind speed variation. The reduced dynamics considered in this work are the rotatio...... predictive controller are presented. Statistical comparison between frequency weighted MPC, standard MPC and baseline PI controller is shown as well.......This work is focused on applying frequency weighted model predictive control (FMPC) on three blade horizontal axis wind turbine (HAWT). A wind turbine is a very complex, non-linear system influenced by a stochastic wind speed variation. The reduced dynamics considered in this work...... are the rotational degree of freedom of the rotor and the tower for-aft movement. The MPC design is based on a receding horizon policy and a linearised model of the wind turbine. Due to the change of dynamics according to wind speed, several linearisation points must be considered and the control design adjusted...

  12. A Comparison of Wind Speed Data from Mechanical and Ultrasonic Anemometers

    Science.gov (United States)

    Short, D.; Wells, L.; Merceret, F.; Roeder, W. P.

    2006-01-01

    This study compared the performance of mechanical and ultrasonic anemometers at the Eastern Range (ER; Kennedy Space Center and Cape Canaveral Air Force Station on Florida's Atlantic coast) and the Western Range (WR; Vandenberg Air Force Base on California's Pacific coast). Launch Weather Officers, forecasters, and Range Safety analysts need to understand the performance of wind sensors at the ER and WR for weather warnings, watches, advisories, special ground processing operations, launch pad exposure forecasts, user Launch Commit Criteria (LCC) forecasts and evaluations, and toxic dispersion support. The current ER and WR weather tower wind instruments are being changed from the current propeller-and-vane (ER) and cup-and-vane (WR) sensors to ultrasonic sensors through the Range Standardization and Automation (RSA) program. The differences between mechanical and ultrasonic techniques have been found to cause differences in the statistics of peak wind speed in previous studies. The 45th Weather Squadron (45 WS) and the 30th Weather Squadron (30 WS) requested the Applied Meteorology Unit (AMU) to compare data between RSA and current sensors to determine if there are significant differences. Approximately 3 weeks of Legacy and RSA wind data from each range were used in the study, archived during May and June 2005. The ER data spanned the full diurnal cycle, while the WR data was confined to 1000-1600 local time. The sample of 1-minute data from numerous levels on 5 different towers on each range totaled more than 500,000 minutes of data (482,979 minutes of data after quality control). The 10 towers were instrumented at several levels, ranging from 12 ft to 492 ft above ground level. The RSA sensors were collocated at the same vertical levels as the present sensors and typically within 15 ft horizontally of each another. Data from a total of 53 RSA ultrasonic sensors, collocated with present sensors were compared. The 1-minute average wind speed/direction and the 1

  13. Small wind power plants : results of the Nordic wind diesel projects for large telecommunications companies; Implantation d'une centrale eolienne comme source d'energie d'appoint pour des stations de telecommunications

    Energy Technology Data Exchange (ETDEWEB)

    Ilinca, A.; Chaumel, J.L. [ATI Eolien, Rimouski, PQ (Canada); Thibault, G. [Entreprises MB, PQ (Canada)

    2005-07-01

    Two wind-diesel generating stations have been installed at telecommunication towers in the remote communities of Kuujjuarapik and Lac Julien in northern Quebec. The use of wind power contributes to the sustainable development in these remote areas by lowering the reliance on costly helicopter-transported diesel fuel and by reducing the release of greenhouse gases to the atmosphere. The technical characteristics of the Bergey 100 kW turbine with battery charger were presented along with the technical characteristics of the EolDie control panel that controls the supply of electricity from either the wind or diesel power generators. For the first time, the ATI-Wind technology system that was installed can supply the needs of the large telecommunication towers of Bell Canada and Telebec from either the wind or the diesel generators. The system is also capable of shutting down the diesel generators when wind energy is sufficient to take over. Early results from June 2005 showed that the diesel generators could be turned off for 55 per cent of the time. Preliminary results of these 2 projects were discussed by the firms in charge of the diesel and wind aspects and recommendations for improvements to the control systems were presented. 11 figs.

  14. Wind seismic noise introduced by external infrastructure: field data and transfer mechanism

    Science.gov (United States)

    Martysevich, Pavel; Starovoyt, Yuri

    2017-04-01

    Background seismic noise generated by wind was analyzed at six co-located seismic and infrasound arrays with the use of the wind speed data. The main factors affecting the noise level were identified as (a) external structures as antenna towers for intrasite communication, vegetation and heavy solar panels fixtures, (b) borehole casing and (c) local lithology. The wind-induced seismic noise peaks in the spectra can be predicted by combination of inverted pendulum model for antenna towers and structures used to support solar panels, free- or clamped-tube resonance of the borehole casing and is dependent on the type of sedimentary upper layer. Observed resonance frequencies are in agreement with calculated clamped / free tube modes for towers and borehole casings. Improvement of the seismic data quality can be achieved by minimizing the impact of surrounding structures close to seismic boreholes. The need and the advantage of the borehole installation may vanish and appear to be even not necessary at locations with non-consolidated sediments because the impact of surrounding structures on seismic background may significantly deteriorate the installation quality and therefore the detection capability of the array. Several IMS arrays where the radio telemetry antennas are used for data delivery to the central site may benefit from the redesign of the intrasite communication system by its substitute with the fiber-optic net as less harmful engineering solution.

  15. Transmission Tower Environment Monitoring Using UAV

    International Nuclear Information System (INIS)

    Redzuwan, Redia Mohd; Din, Norashidah Md; Baharuddin, Mohd Zafri; Mustafa, Intan Shafinaz; Omar, Rohayu Che'

    2013-01-01

    Power utility engineers used to conduct ground survey to collect topographic data. Therefore, they can get detailed and accurate information, but these techniques take a lot of labors and expenses, and spending times for the surveying. An attractive solution to the ground survey is using images taken using Unmanned Aerial Vehicle (UAV). Images captured from UAV can be collected quickly and efficiently over the same area covered in the land survey, in a fraction of the time. The purpose of this research is to mosaic the large numbers of spectral images together into a region wide panoramic image which allows experts to analyze the data for transmission tower monitoring purposes.

  16. Cooling towers of nuclear power plants

    International Nuclear Information System (INIS)

    Mikyska, L.

    1986-01-01

    The specifications are given of cooling towers of foreign nuclear power plants and a comparison is made with specifications of cooling towers with natural draught in Czechoslovak nuclear power plants. Shortcomings are pointed out in the design of cooling towers of Czechoslovak nuclear power plants which have been derived from conventional power plant design. The main differences are in the adjustment of the towers for winter operation and in the designed spray intensity. The comparison of selected parameters is expressed graphically. (J.B.)

  17. Fuzzy Logic Based Multi-Criteria Wind Turbine Selection Strategy—A Case Study of Qassim, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Shafiqur Rehman

    2016-10-01

    Full Text Available The emergence of wind energy as a potential alternative to traditional sources of fuel has prompted notable research in recent years. One primary factor contributing to efficient utilization of wind energy from a wind farm is the type of turbines used. However, selection of a specific wind turbine type is a difficult task due to several criteria involved in the selection process. Important criteria include turbine’s power rating, height of tower, energy output, rotor diameter, cut-in wind speed, and rated wind speed. The complexity of this selection process is further amplified by the presence of conflicts between the decision criteria. Therefore, a decision is desired that provides the best balance between all selection criteria. Considering the complexities involved in the decision-making process, this paper proposes a two-level decision turbine selection strategy based on fuzzy logic and multi-criteria decision-making (MCDM approach. More specifically, the fuzzy arithmetic mean operator is used in the decision process. The proposed approach is applied to wind data collected from the site of Qassim, Saudi Arabia. Results indicate that the proposed approach was effective in finding the optimal turbine from a set of 20 turbines of various capacities.

  18. Cooling tower modification for intermittent operation

    International Nuclear Information System (INIS)

    Midkiff, W.S.

    1975-03-01

    One of the cooling towers at Los Alamos Scientific Laboratory is being operated intermittently. The cooling tower has been modified to restrict air flow and to keep the tower from drying out. The modifications are relatively inexpensive, simple to operate, and have proved effective. (U.S.)

  19. The New WindForS Wind Energy Test Site in Southern Germany

    Science.gov (United States)

    Clifton, A. J.

    2017-12-01

    Wind turbines are increasingly being installed in complex terrain where patchy landcover, forestry, steep slopes, and complex regional and local atmospheric conditions lead to major challenges for traditional numerical weather prediction methods. In this presentation, the new WindForS complex terrain test site will be introduced. WindForS is a southern Germany-based research consortium of more than 20 groups at higher education and research institutes, with strong links to regional government and industry. The new test site will be located in the hilly, forested terrain of the Swabian Alps between Stuttgart and Germany, and will consist of two wind turbines with four meteorological towers. The test site will be used for accompanying ecological research and will also have mobile eddy covariance measurement stations as well as bird and bat monitoring systems. Seismic and noise monitoring systems are also planned. The large number of auxiliary measurements at this facility are intended to allow the complete atmosphere-wind turbine-environment-people system to be characterized. This presentation will show some of the numerical weather prediction work and measurements done at the site so far, and inform the audience about WindForS' plans for the future. A major focus of the presentation will be on opportunities for collaboration through field campaigns or model validation.

  20. Legionella species colonization in cooling towers: risk factors and assessment of control measures.

    Science.gov (United States)

    Mouchtouri, Varvara A; Goutziana, Georgia; Kremastinou, Jenny; Hadjichristodoulou, Christos

    2010-02-01

    Cooling towers can be colonized by Legionella spp, and inhalation of aerosols generated by their operation may cause Legionnaires' disease in susceptible hosts. Environmental investigations of Legionnaires' disease outbreaks linked with cooling towers have revealed poorly maintained systems, lack of control measures, and failure of system equipment. The purpose of this study was to identify Legionella-contaminated cooling towers, identify risk factors for contamination, and assess the effectiveness of control measures. A total of 96 cooling towers of public buildings were registered and inspected, and 130 samples were collected and microbiologically tested. Microbiological test results were associated with characteristics of cooling towers, water samples, inspection results, and maintenance practices. Of the total 96 cooling towers examined, 47 (48.9%) were colonized by Legionella spp, and 22 (22.9%) required remedial action. A total of 65 samples (50.0%) were positive (> or = 500 cfu L(-1)), and 30 (23%) were heavily contaminated (> or = 10(4) cfu L(-1)). Of the 69 isolates identified, 55 strains (79.7.%) were L pneumophila. Legionella colonization was positively associated with the absence of training on Legionella control (relative risk [RR] = 1.66; P = .02), absence of regular Legionella testing (RR = 2.07: P = .002), absence of sunlight protection (RR = 1.63: P = .02), with samples in which the free residual chlorine level in the water sample was cooling towers (median, 17 years; interquartile range [IQR] =5.0 to 26.0 years) compared with noncolonized cooling towers (median age, 6 years; IQR =1.0 to 13.5 years). After the 22 legionellae-positive cooling towers were disinfected with chlorine, 2 (9%) of them remained positive for Legionella spp with a concentration > or = 1000 cfu L(-1). Cooling towers can be heavily colonized by Legionella spp and thus present a potential risk for infection. This study demonstrates the importance of a risk assessment and

  1. Comparing avian and bat fatality rate estimates among North American wind energy projects

    Energy Technology Data Exchange (ETDEWEB)

    Smallwood, Shawn

    2011-07-01

    Full text: Wind energy development has expanded rapidly, and so have concerns over bird and bat impacts caused by wind turbines. To assess and compare impacts due to collisions, investigators use a common metric, fatalities/MW/year, but estimates of fatality rates have come from various wind turbine models, tower heights, environments, fatality search methods, and analytical methods. To improve comparability and asses large-scale impacts, I applied a common set of assumptions and methods to data in fatality monitoring reports to estimate fatality rates of birds and bats at 71 wind projects across North America (52 outside the Altamont Pass Wind Resource Area, APWRA). The data were from wind turbines of 27 sizes (range 0.04-3.00 MW) and 28 tower heights (range 18.5-90 m), and searched at 40 periodic intervals (range 1-90 days) and out to 20 distances from turbines (range 30-126 m). Estimates spanned the years 1982 to 2010, and involved 1-1,345 turbines per unique combination of project, turbine size, tower height, and search methodology. I adjusted fatality rates for search detection rates averaged from 425 detection trials, and for scavenger removal rates based on 413 removal trials. I also adjusted fatality rates for turbine tower height and maximum search radius, based on logistic functions fit to cumulative counts of carcasses that were detected at 1-m distance intervals from the turbine. For each tower height, I estimated the distance at which cumulative carcass counts reached an asymptote, and for each project I calculated the proportion of fatalities likely not found due to the maximum search radius being short of the model-predicted distance asymptote. I used the same estimator in all cases. I estimated mean fatalities/MW/year among North American wind projects at 12.6 bats (80% CI: 8.1-17.1) and 11.1 birds (80% CI: 9.5-12.7), including 1.6 raptors (80% CI: 1.3-2.0), and excluding the Altamont Pass I estimated fatality rates at 17.2 bats (80% CI: 9

  2. Comparison of Observed Temperature and Wind in Mountainous and Coastal Regions in Korea

    Science.gov (United States)

    Park, Y. S.

    2015-12-01

    For more than one year, temperature and wind are observed at several levels in three different environments in Korea. First site is located in a ski jump stadium in a mountain area and observations are performed at 5 heights. Second site is located in an agricultural land 1.4km inland from the seaside and the observing tower is 300m tall. Third site is located in the middle of sea 30km away from the seaside and the tower is 100m tall. The vertical gradients of air temperature are compared on the daily and seasonal bases. Not only the strengths of atmospheric stability are analyzed but also the times when the turnover of the signs of vertical gradients of temperature are occurred. The comparison is also applied to vertical gradients of wind speed and turning of wind direction due to surface slope and sea/land breeze. This study may suggest characteristics of local climate over different environments quantitatively.

  3. Reducing Turbine Mechanical Loads Using Flow Model-Based Wind Farm Controller

    DEFF Research Database (Denmark)

    Kazda, Jonas; Cutululis, Nicolaos Antonio

    Cumulated O&M costs of offshore wind farms are comparable with wind turbine CAPEX of such wind farm. In wind farms, wake effects can result in up to 80% higher fatigue loads at downstream wind turbines [1] and consequently larger O&M costs. The present work therefore investigates to reduce...... these loads during the provision of grid balancing services using optimal model-based wind farm control. Wind farm controllers coordinate the operating point of wind turbines in a wind farm in order to achieve a given objective. The investigated objective of the control in this work is to follow a total wind...... farm power reference while reducing the tower bending moments of the turbines in the wind farm. The wind farm controller is tested on a 8 turbine array, which is representative of a typical offshore wind farm. The operation of the wind farm is simulated using the dynamic wind farm simulation tool S imWind...

  4. Repetitive model predictive approach to individual pitch control of wind turbines

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob; Odgaard, Peter Fogh

    2011-01-01

    prediction. As a consequence, individual pitch feed-forward control action is generated by the controller, taking ”future” wind disturbance into account. Information about the estimated wind spatial distribution one blade experience can be used in the prediction model to better control the next passing blade......Wind turbines are inherently exposed to nonuniform wind fields with of wind shear, tower shadow, and possible wake contributions. Asymmetrical aerodynamic rotor loads are a consequence of such periodic, repetitive wind disturbances experienced by the blades. A controller may estimate and use...... this peculiar disturbance pattern to better attenuate loads and regulate power by controlling the blade pitch angles individually. A novel model predictive (MPC) approach for individual pitch control of wind turbines is proposed in this paper. A repetitive wind disturbance model is incorporated into the MPC...

  5. Design, numerical modelling and analysis of a spar floater supporting the DTU 10MW wind turbine

    OpenAIRE

    Xue, Wenfei

    2016-01-01

    Nowadays, wind energy is one of the most promising, sustainable and clean energy solutions for the future. The wind industry in Europe experiences a very fast development these years, moving from onshore to offshore in shallow water and then in deep water. A floating wind turbine is an offshore wind turbine mounted on a floating structure that allows the turbine to generate electricity in water depths where bottom-fixed towers are not accessible. However, the offshore wind energy still has...

  6. Fuzzy Logic Based Multi-Criteria Wind Turbine Selection Strategy—A Case Study of Qassim, Saudi Arabia

    OpenAIRE

    Shafiqur Rehman; Salman A. Khan

    2016-01-01

    The emergence of wind energy as a potential alternative to traditional sources of fuel has prompted notable research in recent years. One primary factor contributing to efficient utilization of wind energy from a wind farm is the type of turbines used. However, selection of a specific wind turbine type is a difficult task due to several criteria involved in the selection process. Important criteria include turbine’s power rating, height of tower, energy output, rotor diameter, cut-in wind spe...

  7. Prediction of a Visible Plume from a Dry and Wet Combined Cooling Tower and Its Mechanism of Abatement

    Directory of Open Access Journals (Sweden)

    Kazutaka Takata

    2016-04-01

    Full Text Available Heated moist air from a cooling tower forms a visible plume and needs to be predicted, not only for the performance design of the cooling tower, but also for environmental impact assessments. In this study, a computational fluid dynamics analysis is conducted to predict the scale of a visible plume rising from a cross flow cooling tower with mechanical draft (provided by a rotating fan. The results of computational fluid dynamics analysis are verified by comparing predictions with an actual observed plume. The results show that the predicted visible plume represents the observed plume in an error range of 15%–20%, which is permissible for designing a cooling tower. Additionally, the mixing condition of heated dry air and moist air under dry and wet combined operation is examined, and the condition is thought to affect the scale of the visible plume. It is found that, in the case of a mechanical-draft cooling tower, the fan has a mixing function which performs the complete mixing of wet and dry air, and this suggests that the generation of the plume can be determined by the intersection of the operation line and saturation line. Additionally, the effect of external wind on the scale of the visible plume is large, especially for dry and wet combined operation.

  8. Site-optimization of wind turbine generators

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, T.J. de; Thillerup, J. [Nordtank Energy Group, Richmond, VA (United States)

    1997-12-31

    The Danish Company Nordtank is one of the pioneers within the wind turbine industry. Since 1981 Nordtank has installed worldwide more than 2500 wind turbine generators with a total name plate capacity that is exceeding 450 MW. The opening up of new and widely divergent markets has demanded an extremely flexible approach towards wind turbine construction. The Nordtank product range has expanded considerable in recent years, with the main objective to develop wind energy conversion machines that can run profitable in any given case. This paper will describe site optimization of Nordtank wind turbines. Nordtank has developed a flexible design concept for its WTGs in the 500/750 kW range, in order to offer the optimal WTG solution for any given site and wind regime. Through this flexible design, the 500/750 turbine line can adjust the rotor diameter, tower height and many other components to optimally fit the turbine to each specific project. This design philosophy will be illustrated with some case histories of recently completed projects.

  9. Component for articulated offshore loading towers

    Energy Technology Data Exchange (ETDEWEB)

    Backhaus, H.

    1980-09-01

    The construction of offshore natural gas liquefaction plants must be regarded as technically feasible and the marketing prospects for LNG - a source of clean burning energy - appear excellent. Nevertheless, the optimum loading procedure for LNG tankers in the - sometimes adverse - offshore environment is still a matter under discussion by the experts - with a tendency to adopt and adapt well-proven components from the offshore crude oil sector. Here, articulated towers are in use for tankerloading and the crude oil is pumped at ambient temperature through the cardan joint of the tower itself. In the case of the cryogenic liquid LNG, this method would entail intolerable risks. Leaks and subsequent LNG spills within the tower joint will cause low temperature-embrittlement and most likely damage the cardan connection at the tower's base plate on the sea bed. The described submarine joint for ultra-cold liquids, which has the same cardanic properties as the cardan joint of the tower is completely separated from the latter. Thus a cryogenic leakage in this submarine joint will under no circumstance reach and affect the tower cardan.

  10. Radio Transmitters and Tower Locations, Layer includes all towers identified visually and include cellular and other communication towers., Published in 2008, 1:1200 (1in=100ft) scale, Noble County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Radio Transmitters and Tower Locations dataset current as of 2008. Layer includes all towers identified visually and include cellular and other communication towers..

  11. Dynamic Analysis of Wind Turbines Including Soil-Structure Interaction

    DEFF Research Database (Denmark)

    Harte, M.; Basu, B.; Nielsen, Søren R.K.

    2012-01-01

    This paper investigates the along-wind forced vibration response of an onshore wind turbine. The study includes the dynamic interaction effects between the foundation and the underlying soil, as softer soils can influence the dynamic response of wind turbines. A Multi-Degree-of-Freedom (MDOF......) horizontal axes onshore wind turbine model is developed for dynamic analysis using an Euler–Lagrangian approach. The model is comprised of a rotor blade system, a nacelle and a flexible tower connected to a foundation system using a substructuring approach. The rotor blade system consists of three rotating...... for displacement of the turbine system are obtained and the modal frequencies of the combined turbine-foundation system are estimated. Simulations are presented for the MDOF turbine structure subjected to wind loading for different soil stiffness conditions. Steady state and turbulent wind loading, developed using...

  12. Multi-hazard response analysis of a 5MW offshore wind turbine

    DEFF Research Database (Denmark)

    Katsanos, Evangelos; Sanz, A. Arrospide; Georgakis, Christos T.

    2017-01-01

    Wind energy has already dominant role on the scene of the clean energy production. Well-promising markets, like China, India, Korea and Latin America are the fields of expansion for new wind turbines mainly installed in offshore environment, where wind, wave and earthquake loads threat...... of the blades, the nacelle, the tower and the monopile was developed with the use of an aeroelastic code considering the interaction between the elastic and inertial forces, developed in the structure, as well as the generated aerodynamic and hydrodynamic forces. Based on the analysis results, the dynamic...

  13. Duration Test Report for the Ventera VT10 Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.; Huskey, A.; Jager, D.; Hur, J.

    2013-06-01

    This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small wind turbines. Five turbines were tested at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) as a part of round one of this project. Duration testing is one of up to five tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality. Test results will provide manufacturers with reports that can be used to fulfill part of the requirements for small wind turbine certification. The test equipment included a grid-connected Ventera Energy Corporation VT10 wind turbine mounted on an 18.3-m (60-ft) self-supporting lattice tower manufactured by Rohn.

  14. The future cooling tower; Fremtidens koeletaarn

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, C.H. (Vestas Aircoil A/S, Lem St. (Denmark)); Schneider, P. (Teknologisk Institut, AArhus (Denmark)); Haaning, N. (Ramboell A/S, Copenhagen (Denmark)); Lund, K. (Nyrup Plast A/S, Nyrup (Denmark)); Soerensen, Ole (MultiWing A/S, Vedbaek (Denmark)); Dalsgaard, T. (Silhorko A/S, Skanderborg (Denmark)); Pedersen, Michael (Skive Kommune, Skive (Denmark))

    2011-03-15

    This project has designed and built a pilot-scale cooling tower with an output of up to 100 kW for which good correlation has been ascertained between measured and calculated values for output and pressure loss. The new cooling tower will save approximately 15% of electricity consumption compared with the widespread dry coolers. The pilot tower uses rainwater so that both water consumption and electricity consumption are saved in softening plants. On the basis of this cooling tower, models have been made and these have been implemented in PackCalc II in order to calculate electricity and other operating savings. (Energy 11)

  15. Gone with the wind: Do we know the impact that produce wind energy causes on flying vertebrates of Costa Rica?

    Directory of Open Access Journals (Sweden)

    Victor J. Acosta-Chaves

    2017-12-01

    Full Text Available The clean energy industry has been growing in Costa Rica, especially wind energy, during the last years. However, at least for the best of our knowledge, published scientific information about diversity, and collision rates, upon bats and birds in wind farms of Costa Rica is not-existent. In this manuscript we highlight the importance of establish biological monitoring programs in the wind farms, to determinate changes in the diversity of flying vertebrates, as well to evaluate the impact of wind towers upon the local and regional biodiversity. We suggest to public and private actors involving in wind energy production and conservation in Costa Rica to work together in order to answer the questions formulated in this manuscript as a priority, and eventually mitigate effectively any potential threat on our biodiversity. The development of research and politics related with those issues is critical to make correct decisions in relation with the wind energy future of the country in armony with nature.

  16. Automated prediction of boundary layer winds and turbulence for the Savannah River Laboratory. Final report

    International Nuclear Information System (INIS)

    Gilhousen, D.B.

    1979-01-01

    Objective forecasts of many weather elements produced twice daily for about 230 US cities are made by applying the Model Output Statistics (MOS) technique (Glahn and Lowry, 1972). This technique relates by a statistical method the output of numerical models interpolated to a location (predictors) to a corresponding sample of observed local weather at that location (predictand). This study describes the development and testing of MOS wind forecasts for an instrumented TV tower located near the Savannah River Laboratory (SRL). If shown to be useful, these forecasts could serve as valuable guidance in case of a nuclear incident at the installation. This study introduces several new applications of the MOS technique. In addition to forecasts of wind speed and direction, forecasts of two turbulence parameters were developed and evaluated. These turbulence parameters were the standard deviations of both the azimuth and elevation of the wind. These quantities help to estimate the amount of plume and puff spread. Forecasts of all these elements were produced for several levels on the 335 m WJBF-TV tower. Tests were conducted to see if MOS forecasts of each element were capable of resolving differences between tower levels. MOS forecasts were compared to two other types of forecasts to determine their utility. Short range persistence forecasts served as one type of comparison since SRL uses the current observed winds in their diffusion models. Climatology forecasts served as the other comparison set

  17. Final Report for Project: Impacts of stratification and non-equilibrium winds and waves on hub-height winds

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Edward G. [Univ. Corporation for Atmospheric Research, Boulder, CO (United States)

    2015-07-14

    wind plant scale. Overall project conclusions include; In the presence of fast-moving swell (significant wave height Hs = 6.4 m, and phase speed cp = 18 ms-1), the atmospheric boundary layer grows more rapidly when waves propagate opposite to the winds compared to when winds and waves are aligned. Pressure drag increases by nearly a factor of 2 relative to the turbulent stress for the extreme case where waves propagate at 180° compared to the pressure gradient forcing. Net wind speed reduces by nearly 15% at hub-height for the 180°-case compared to the 0°-case, and turbulence intensities increase by nearly a factor of 2. These impacts diminish with decreasing wave age; Stratification increases hub height wind speeds and increases the vertical shear of the mean wind across the rotor plane. Fortuitously, this stability-induced enhanced shear does not influence turbulence intensity at hub height, but does increase (decrease) turbulence intensity below (above) hub height. Increased stability also increases the wave-induced pressure stress by ~ 10%; Off the East Coast of the United States during Coupled Boundary Layers Air-Sea Transfer - Low Wind (CBLAST-Low), cases with short fetch include thin stable boundary layers with depths of only a few tens of meters. In the coastal zone, the relationship between the mean wind and the surface fiction velocity (u*(V )) is significantly related to wind direction for weak winds but is not systematically related to the air sea difference of virtual potential temperature, δθv; since waves generally propagate from the south at the Air-Sea Interaction Tower (ASIT) tower, these results suggest that under weak wind conditions waves likely influence surface stress more than stratification does; and Winds and waves are frequently misaligned in the coastal zone. Stability conditions persist for long duration. Over a four year period, the Forschungsplattformen in Nord- und Ostsee Nr. 1 (FINO1) tower (a site with long fetch

  18. Trailing edge devices to improve performance and increase lifetime of wind-electric water pumping systems

    Energy Technology Data Exchange (ETDEWEB)

    Vick, B.D.; Clark, R.N. [USDA-Agricultural Research Service, Bushland, TX (United States)

    1996-12-31

    Trailing edge flaps were applied to the blades of a 10 kW wind turbine used for water pumping to try to improve the performance and decrease the structural fatigue on the wind turbine. Most small wind turbines (10 kW and below) use furling (rotor turns out of wind similar to a mechanical windmill) to protect the wind turbine from overspeed during high winds. Some small wind turbines, however, do not furl soon enough to keep the wind turbine from being off line part of the time in moderately high wind speeds (10 - 16 m/s). As a result, the load is disconnected and no water is pumped at moderately high wind speeds. When the turbine is offline, the frequency increases rapidly often causing excessive vibration of the wind turbine and tower components. The furling wind speed could possibly be decreased by increasing the offset between the tower centerline and the rotor centerline, but would be a major and potentially expensive retrofit. Trailing edge flaps (TEF) were used as a quick inexpensive method to try to reduce the furling wind speed and increase the on time by reducing the rotor RPM. One TEF configuration improved the water pumping performance at moderately high wind speeds, but degraded the pumping performance at low wind speeds which resulted in little change in daily water volume. The other TEF configuration differed very little from the no flap configuration. Both TEF configurations however, reduced the rotor RPM in high wind conditions. The TEF, did not reduce the rotor RPM by lowering the furling wind speed as hoped, but apparently did so by increasing the drag which also reduced the volume of water pumped at the lower wind speeds. 6 refs., 9 figs.

  19. A new method for wind speed forecasting based on copula theory.

    Science.gov (United States)

    Wang, Yuankun; Ma, Huiqun; Wang, Dong; Wang, Guizuo; Wu, Jichun; Bian, Jinyu; Liu, Jiufu

    2018-01-01

    How to determine representative wind speed is crucial in wind resource assessment. Accurate wind resource assessments are important to wind farms development. Linear regressions are usually used to obtain the representative wind speed. However, terrain flexibility of wind farm and long distance between wind speed sites often lead to low correlation. In this study, copula method is used to determine the representative year's wind speed in wind farm by interpreting the interaction of the local wind farm and the meteorological station. The result shows that the method proposed here can not only determine the relationship between the local anemometric tower and nearby meteorological station through Kendall's tau, but also determine the joint distribution without assuming the variables to be independent. Moreover, the representative wind data can be obtained by the conditional distribution much more reasonably. We hope this study could provide scientific reference for accurate wind resource assessments. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Cooling towers principles and practice

    CERN Document Server

    Hill, G B; Osborn, Peter D

    1990-01-01

    Cooling Towers: Principles and Practice, Third Edition, aims to provide the reader with a better understanding of the theory and practice, so that installations are correctly designed and operated. As with all branches of engineering, new technology calls for a level of technical knowledge which becomes progressively higher; this new edition seeks to ensure that the principles and practice of cooling towers are set against a background of up-to-date technology. The book is organized into three sections. Section A on cooling tower practice covers topics such as the design and operation of c

  1. An Analysis of Peak Wind Speed Data from Collocated Mechanical and Ultrasonic Anemometers

    Science.gov (United States)

    Short, David A.; Wells, Leonard; Merceret, Francis J.; Roeder, William P.

    2007-01-01

    This study compared peak wind speeds reported by mechanical and ultrasonic anemometers at Cape Canaveral Air Force Station and Kennedy Space Center (CCAFS/KSC) on the east central coast of Florida and Vandenberg Air Force Base (VAFB) on the central coast of California. Launch Weather Officers, forecasters, and Range Safety analysts need to understand the performance of wind sensors at CCAFS/KSC and VAFB for weather warnings, watches, advisories, special ground processing operations, launch pad exposure forecasts, user Launch Commit Criteria (LCC) forecasts and evaluations, and toxic dispersion support. The legacy CCAFS/KSC and VAFB weather tower wind instruments are being changed from propeller-and-vane (CCAFS/KSC) and cup-and-vane (VAFB) sensors to ultrasonic sensors under the Range Standardization and Automation (RSA) program. Mechanical and ultrasonic wind measuring techniques are known to cause differences in the statistics of peak wind speed as shown in previous studies. The 45th Weather Squadron (45 WS) and the 30th Weather Squadron (30 WS) requested the Applied Meteorology Unit (AMU) to compare data between the RSA ultrasonic and legacy mechanical sensors to determine if there are significant differences. Note that the instruments were sited outdoors under naturally varying conditions and that this comparison was not designed to verify either technology. Approximately 3 weeks of mechanical and ultrasonic wind data from each range from May and June 2005 were used in this study. The CCAFS/KSC data spanned the full diurnal cycle, while the VAFB data were confined to 1000-1600 local time. The sample of 1-minute data from numerous levels on five different towers on each range totaled more than 500,000 minutes of data (482,979 minutes of data after quality control). The ten towers were instrumented at several levels, ranging from 12 ft to 492 ft above ground level. The ultrasonic sensors were collocated at the same vertical levels as the mechanical sensors and

  2. Proceedings: Cooling tower and advanced cooling systems conference

    International Nuclear Information System (INIS)

    1995-02-01

    This Cooling Tower and Advanced Cooling Systems Conference was held August 30 through September 1, 1994, in St. Petersburg, Florida. The conference was sponsored by the Electric Power Research Institute (EPRI) and hosted by Florida Power Corporation to bring together utility representatives, manufacturers, researchers, and consultants. Nineteen technical papers were presented in four sessions. These sessions were devoted to the following topics: cooling tower upgrades and retrofits, cooling tower performance, cooling tower fouling, and dry and hybrid systems. On the final day, panel discussions addressed current issues in cooling tower operation and maintenance as well as research and technology needs for power plant cooling. More than 100 people attended the conference. This report contains the technical papers presented at the conference. Of the 19 papers, five concern cooling tower upgrades and retrofits, five to cooling tower performance, four discuss cooling tower fouling, and five describe dry and hybrid cooling systems. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

  3. Occurrence of Infected Free-Living Amoebae in Cooling Towers of Southern Brazil.

    Science.gov (United States)

    Soares, Scheila S; Souza, Thamires K; Berté, Francisco K; Cantarelli, Vlademir V; Rott, Marilise B

    2017-12-01

    This study determined the occurrence of potentially pathogenic free-living amoebae (FLA) and bacteria associated with amoebae in air-conditioning cooling towers in southern Brazil. Water samples were collected from 36 cooling systems from air-conditioning in the state of Rio Grande do Sul, Brazil. The organisms were identified using polymerase chain reaction (PCR) and sequencing automated. The results showed that these aquatic environments, with variable temperature, are potential "hot spots" for emerging human pathogens like free-living amoebae and bacteria associated. In total, 92% of the cooling-tower samples analyzed were positive for FLA, and Acanthamoeba was the dominant genus by culture and PCR. Amoebal isolates revealed intracellular bacteria in 39.3% of them and all were confirmed as members of the genus Pseudomonas. The results obtained show the important role of cooling towers as a source of amoebae-associated pathogens.

  4. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    OpenAIRE

    Weihao Hu; Yunqian Zhang; Zhe Chen; Yanting Hu

    2013-01-01

    Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG) developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution) power oscillation due to wind shear and tower shadow effects is the sign...

  5. The Feasibility of Utilizing Wind Energy in Commercial Buildings With Special Reference to the Kingdom of Bahrain

    Science.gov (United States)

    Abdulrahim Saeed, Saeed

    2017-11-01

    This article shall investigate the feasibility of utilizing wind energy for commercial buildings with special reference to the Kingdom of Bahrain. Bahrain World Trade Center which was built in 2008, is located in the city of Manama. The fifty-story complex contains identical twin towers that rise over 240 meters in height. The towers are connected by three bridges which hold three turbines each 29 meters long. The three turbines were originally design to provide electric energy required for lighting. The Bahrain World Trade Center was selected as a case study to investigate the feasibility of utilizing wind energy technologies in skyscrapers with special reference to the Kingdom of Bahrain. It is hoped that the findings and conclusion of the study shall be of some value for future utilization of wind energy in the GCC countries and the world at large.

  6. Analyzing the requirements for mass production of small wind turbine generators

    Science.gov (United States)

    Anuskiewicz, T.; Asmussen, J.; Frankenfield, O.

    Mass producibility of small wind turbine generators to give manufacturers design and cost data for profitable production operations is discussed. A 15 kW wind turbine generator for production in annual volumes from 1,000 to 50,000 units is discussed. Methodology to cost the systems effectively is explained. The process estimate sequence followed is outlined with emphasis on the process estimate sheets compiled for each component and subsystem. These data enabled analysts to develop cost breakdown profiles crucial in manufacturing decision-making. The appraisal also led to various design recommendations including replacement of aluminum towers with cost effective carbon steel towers. Extensive cost information is supplied in tables covering subassemblies, capital requirements, and levelized energy costs. The physical layout of the plant is depicted to guide manufacturers in taking advantage of the growing business opportunity now offered in conjunction with the national need for energy development.

  7. BOREAS TF-10 NSA-Fen Tower Flux and Meteorological Data

    Science.gov (United States)

    McCaughey, J. Harry; Hall, Forrest G. (Editor); Huemmrich, Karl (Editor); Jelinski, Dennis E.

    2000-01-01

    The BOREAS TF-10 team collected tower flux and meteorological data at two sites, a fen and a young jack pine forest, near Thompson, Manitoba, Canada, as part of BOREAS. A preliminary data set was assembled in August 1993 while field testing the instrument packages, and at both sites data were collected from 15-Aug to 31-Aug. The main experimental period was in 1994, when continuous data were collected from 08-Apr to 23-Sep at the fen site. A very limited experiment was run in the spring/ summer of 1995, when the fen site tower was operated from 08-Apr to 14-Jun in support of a hydrology experiment in an adjoining feeder basin. Upon examination of the 1994 data set, it became clear that the behavior of the heat, water, and carbon dioxide fluxes throughout the whole growing season was an important scientific question, and that the 1994 data record was not sufficiently long to capture the character of the seasonal behavior of the fluxes. Thus, the fen site was operated in 1996 in order to collect data from spring melt to autumn freeze-up. Data were collected from 29-Apr to 05-Nov at the fen site. All variables are presented as 30-minute averages. The data are stored in tabular ASCII files.

  8. A drilling rig tower

    Energy Technology Data Exchange (ETDEWEB)

    Mironov, A.A.; Barashkov, V.A.; Bulgakov, E.S.; Kuldoshin, I.P.; Lebedev, A.I.; Papin, N.M.; Rebrik, B.M.; Sirotkin, N.V.

    1981-05-23

    Presentation is made of a drilling rig tower, comprising a gantry, a support shaft with a bracing strut and drawings out, and turn buckles. In order to increase the reliability of the tower in operation, to decrease the over all dimensions in a transport position, and to decrease the amount of time taken to transfer the tower from an operational position into a transportable one, and vice versa, the tower is equipped with a rotary frame made in the form of a triangular prism, whose lateral edges are connected by hinges: the first one with the lower part of the support shaft, the second with the gantry, and the third one to the upper part of the support shaft by means of the drawings out. The large boundary of the rotary frame is connected by a hinge to the support shaft by means of a bracing strut, which is equipped with a slide block connected to it by a hinge, and the rotary frame has a guide for the slide block reinforced to it on the large boundary. Besides this, the lateral edge of the rotary frame is connected to the gantry by means of turn buckles.

  9. Market Suitability and Performance Tradeoffs Offered by Commercial Wind Turbines across Differing Wind Regimes

    Directory of Open Access Journals (Sweden)

    Souma Chowdhury

    2016-05-01

    Full Text Available The suitability of turbine configurations to different wind resources has been traditionally restricted to considering turbines operating as standalone entities. In this paper, a framework is thus developed to investigate turbine suitability in terms of the minimum cost of energy offered when operating as a group of optimally-micro-sited turbines. The four major steps include: (i characterizing the geographical variation of wind regimes in the onshore U.S. market; (ii determining the best performing turbines for different wind regimes through wind farm layout optimization; (iii developing a metric to quantify the expected market suitability of available turbine configurations; and (iv exploring the best tradeoffs between the cost and capacity factor yielded by these turbines. One hundred thirty one types of commercial turbines offered by major global manufacturers in 2012 are considered for selection. It is found that, in general, higher rated power turbines with medium tower heights are the most favored. Interestingly, further analysis showed that “rotor diameter/hub height” ratios greater than 1.1 are the least attractive for any of the wind classes. It is also observed that although the “cost-capacity factor” tradeoff curve expectedly shifted towards higher capacity factors with increasing wind class, the trend of the tradeoff curve remained practically similar.

  10. The Design of Akhmat Tower

    Science.gov (United States)

    Beardsley, Sara; Stochetti, Alejandro; Cerone, Marc

    2018-03-01

    Akhmat Tower is a 435m supertall building designed by Adrian Smith + Gordon Gill Architecture. It is currently under construction in the city of Grozny, in the Chechen Republic, in the North Caucasus region of Russia. The design of the tower was done during a collaborative process by a multi-disciplinary architectural and engineering team, based primarily in the United States and Russia. During this process, the designers considered many factors including, most primarily, the cultural and historical context, the structural requirements given the high seismicity of the region, and the client's programmatic needs. The resulting crystalline-shaped tower is both an aesthetic statement and a performative architectural solution which will be a new landmark for Chechnya. "The Design of Akhmat Tower" describes in detail the design process including structural considerations, exterior wall design, building program, interior design, the tuned mass damper, and the use of building information modeling.

  11. Study on Tower Models for EHV Transmission Line

    Directory of Open Access Journals (Sweden)

    Xu Bao-Qing

    2016-01-01

    Full Text Available Lightning outage accident is one of the main factors that threat seriously the safe and reliable operation of power system. So it is very important to establish reasonable transmission tower model and evaluate the impulse response characteristic of lightning wave traveling on the transmission tower properly for determining reliable lightning protection performance. With the help of Electromagnetic Transient Program (EMTP, six 500kV tower models are built. Aiming at one line to one transformer operating mode of 500kV substation, the intruding wave overvoltage under different tower models is calculated. The effect of tower model on intruding overvoltage has been studied. The results show that different tower models can result in great differences to the calculation results. Hence, reasonable selection of the tower model in the calculation of back- strike intruding wave is very important.

  12. Numerical techniques for the improved performance of a finite element approach to wind turbine aeroelastics

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, M.B. [Renewable Energy Systems Ltd., Hemel Hempstead (United Kingdom)

    1996-09-01

    It is possible to compute the aeroelastic response of a horizontal axis wind turbine comprising; Structural: rotor substructure 144 dof, tower substructure 48 dof, induction, synchronous or variable speed, and gearbox. Aerodynamic: 3 blades (10 elements per blade), dynamic stall, and 6 different aerofoil types with combination of fixed or pitching elements. Control: stall or power regulation or speed control and shutdowns, wind shear, and tower shadow. Turbulence: 8 radial points, 32 circumferential, and 3 components. On a DEC Alpha Workstation the code will simulate the response inclose to real-time. As the code is presently formulated deflections from the initial starting point have to be small and therefore its ability to fully analyse very flexible structures is limited. (EG)

  13. Kaneohe, Hawaii Wind Resource Assessment Report

    Energy Technology Data Exchange (ETDEWEB)

    Robichaud, R.; Green, J.; Meadows, B.

    2011-11-01

    The Department of Energy (DOE) has an interagency agreement to assist the Department of Defense (DOD) in evaluating the potential to use wind energy for power at residential properties at DOD bases in Hawaii. DOE assigned the National Renewable Energy Laboratory (NREL) to facilitate this process by installing a 50-meter (m) meteorological (Met) tower on residential property associated with the Marine Corps Base Housing (MCBH) Kaneohe Bay in Hawaii.

  14. Performance characteristics of counter flow wet cooling towers

    International Nuclear Information System (INIS)

    Khan, Jameel-Ur-Rehman; Yaqub, M.; Zubair, Syed M.

    2003-01-01

    Cooling towers are one of the biggest heat and mass transfer devices that are in widespread use. In this paper, we use a detailed model of counter flow wet cooling towers in investigating the performance characteristics. The validity of the model is checked by experimental data reported in the literature. The thermal performance of the cooling towers is clearly explained in terms of varying air and water temperatures, as well as the driving potential for convection and evaporation heat transfer, along the height of the tower. The relative contribution of each mode of heat transfer rate to the total heat transfer rate in the cooling tower is established. It is demonstrated with an example problem that the predominant mode of heat transfer is evaporation. For example, evaporation contributes about 62.5% of the total rate of heat transfer at the bottom of the tower and almost 90% at the top of the tower. The variation of air and water temperatures along the height of the tower (process line) is explained on psychometric charts

  15. Atmospheric cooling tower with reduced plume

    International Nuclear Information System (INIS)

    Gautier, D.M.; Lagoutte, A.

    1985-01-01

    The cooling tower, usable in thermal-electric power plants, has a vertical chimney having a central water tower fed with water to be cooled, a pipe network distributing water coming from the water tower and dispersing it in flows streaming down on a packing, and a basin to receive the water cooled by contact with an air flow passing through apertures at the lower part of the chimney and flowing up through the chimney. The cooling tower has inlet air pipes for the said apertures to a zone of the chimney situated beyond the streaming zone, the said pipes being arranged such their surface is swept by water to be cooled [fr

  16. Simulation of a flexible wind turbine response to a grid fault

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Sørensen, Poul Ejnar

    2007-01-01

    The purpose of this work is to illustrate the impact of a grid fault on the mechanical loads of a wind turbine. Grid faults generate transients in the generator electromagnetic torque, which are propagated in the wind turbine, stressing its mechanical components. Grid faults are normally simulated...... in power system simulation tools applying simplified mechanical models of the drive train. This paper presents simulations of the wind turbine load response to grid faults with an advanced aeroelastic computer code (HAWC2). The core of this code is an advanced model for the flexible structure of the wind...... turbines, taking the flexibility of the tower, blades and other components of the wind turbines into account. The effect of a grid fault on the wind turbine flexible structure is assessed for a typical fixed speed wind turbine, equipped with an induction generator....

  17. Lamar Low-Level Jet Program Interim Report

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, N.; Shirazi, M.; Jager, D.; Wilde, S.; Adams, J.; Buhl, M.; Sullivan, P.; Patton, E.

    2004-01-01

    This interim report presents the results to date from the Lamar Low-Level Jet Program (LLLJP) that has been established as joint effort among the U.S. Department of Energy (DOE), the National Wind Technology Center (NWTC) of the National Renewable Energy Laboratory (NREL), and General Electric Wind Energy (GE Wind). The purpose of this project is to develop an understanding of the influence of nocturnal low-level jet streams on the inflow turbulence environment and the documenting of any potential operating impacts on current large wind turbines and the Low Wind Speed Turbine (LWST) designs of the future. A year's record of detailed nocturnal turbulence measurements has been collected from NREL instrumentation installed on the GE Wind 120-m tower in southeastern Colorado and supplemented with mean wind profile data collected using an acoustic wind profiler or SODAR (Sound Detection and Ranging). The analyses of measurements taken as part of a previous program conducted at the NWTC have been used to aid in the interpretation of the results of representative case studies of data collected from the GE Wind tower.

  18. World trends in wind energy

    International Nuclear Information System (INIS)

    Kane, Mamadou

    2016-01-01

    A set of articles proposes an overview of some recent, important and characteristic trends in the field of wind energy all over the world. China, with 30,8 GW of newly installed capacities in 2015 has just overtaken the European Union as far as the total installed power is concerned (145 GW against 142 GW). Job growth in the wind energy sector has reached 20 per cent in the USA in 2015. In this country, major companies held 52 per cent of the market in 2015 while a new American research plan has been approved for the development of offshore wind energy. In South Africa, a German company specialised in blade inspection and repair will provide the Obelisk group with its services on blades and towers for wind turbines. As far as the UK is concerned, the article outlines and comments the continuing decrease of production costs. In India, General Electric is about to launch a new technology of digital wind farm which is supposed to improve production by simulating availability and productivity over the farm lifetime while reducing costs. In Norway, a Norwegian company proposes a new battery-based storage solution, Batwind, for offshore wing energy

  19. Interaction Technology for Collective and Psychomotor Training in Sports

    DEFF Research Database (Denmark)

    Fogtmann, Maiken Hillerup; Grønbæk, Kaj; Ludvigsen, Martin

    2011-01-01

    the kinesthetic empathic elements inherently present within open sports. To put focus on collective training, we draw inspiration from Kinesthetic Empathy Interaction in designing the collective training equipment, TacTowers. The TacTowers prototype is aimed at supporting athletes, particularly team handball...

  20. Towers of the new 380 kV high-voltage overhead line across the Elbe

    Energy Technology Data Exchange (ETDEWEB)

    Kiessling, F; Sperl, H D; Wagemann, F

    1979-11-01

    As part of the European power transmission line between North Sweden and Southern Italy, a 380 kV rotary-current overhead line crosses the Elbe river south of Hamburg. To achieve the overhead clearance of 80 m required for navigation and the maximum line sag of 85 m, two steel trelliswork towers were constructed about 1200 m apart, each of them 227 m high. The 12 phases (cables) of the line are suspended each on three horizontal beams at a horizontal distance of 16 m. Exceptional loads far beyond the standards set in VDE 0210/5.69 have been assumed for the layout. In the case of the wind loads the frequent gales had to be considered; for ice loads, class I of the IEC/TC 11 Draft on Ice loading on Overhead Lines . Amsterdam 1977, was assumed. Some further loads are described as well as the tender procedure, supply and assembly of the towers.

  1. Control Towers in Supply Chain Management - Past and Future

    Directory of Open Access Journals (Sweden)

    Anna Trzuskawska-Grzesińska

    2017-02-01

    Full Text Available The global economy requires global supply chain management which relies on visibility and responsiveness. Determinants such as: information technology tools, process knowledge, sales and operations planning experiences, etc., enable the formation of theory and practice for the supply chain control tower concept. The goal of the research paper is to identify business examples of different approaches to the supply chain control tower in the past and initiate a discussion on their future. This paper synthesizes past control tower practices and identifies possible future trends. The author performed: literature analysis, three selected companies' case studies and comparative analyses. As the control towers evolve, while supply chains are transforming continuous, update from the market is needed. The research findings showed the selected companies, in the future, perceived control tower's activities as a potential source of revenue not just solely a source of cost and time optimization as well as a source of value added to customer. The researched control towers were built and still they are developed. The business frequently changes and requires control towers to be adjusted, reengineered and adaptive. The researched control towers are needed to keep control over supply chain while it is transforming. There is a differentiation between the supply chain control towers, logistic services control towers and reverse supply chain control towers. An integration mechanism between the control towers would be necessary to assure entire supply chain visibility and orchestration. The research also shows the knowledge gap regarding the control towers in supply chain, specially their possible configurations and future.

  2. Evaluation of feasibility of prestressed concrete for use in wind turbine blades

    Science.gov (United States)

    Leiblein, S.; Londahl, D. S.; Furlong, D. B.; Dreier, M. E.

    1979-01-01

    A preliminary evaluation of the feasibility of the use of prestressed concrete as a material for low cost blades for wind turbines was conducted. A baseline blade design was achieved for an experimental wind turbine that met aerodynamic and structural requirements. Significant cost reductions were indicated for volume production. Casting of a model blade section showed no fabrication problems. Coupled dynamic analysis revealed that adverse rotor tower interactions can be significant with heavy rotor blades.

  3. SMART Rotor Development and Wind Tunnel Test

    Science.gov (United States)

    2009-09-01

    amplifier and control system , and data acquisition, processing, and display systems . Boeing�s LRTS (Fig. 2), consists of a sled structure that...Support Test Stand Sled Tail Sting Outrigger Arm Figure 2: System integration test at whirl tower Port Rotor Balance Main Strut Flap Tail...demonstrated. Finally, the reliability of the flap actuation system was successfully proven in more than 60 hours of wind tunnel testing

  4. Computational Acoustic Beamforming for Noise Source Identification for Small Wind Turbines.

    Science.gov (United States)

    Ma, Ping; Lien, Fue-Sang; Yee, Eugene

    2017-01-01

    This paper develops a computational acoustic beamforming (CAB) methodology for identification of sources of small wind turbine noise. This methodology is validated using the case of the NACA 0012 airfoil trailing edge noise. For this validation case, the predicted acoustic maps were in excellent conformance with the results of the measurements obtained from the acoustic beamforming experiment. Following this validation study, the CAB methodology was applied to the identification of noise sources generated by a commercial small wind turbine. The simulated acoustic maps revealed that the blade tower interaction and the wind turbine nacelle were the two primary mechanisms for sound generation for this small wind turbine at frequencies between 100 and 630 Hz.

  5. Statistics Analysis Measures Painting of Cooling Tower

    Directory of Open Access Journals (Sweden)

    A. Zacharopoulou

    2013-01-01

    Full Text Available This study refers to the cooling tower of Megalopolis (construction 1975 and protection from corrosive environment. The maintenance of the cooling tower took place in 2008. The cooling tower was badly damaged from corrosion of reinforcement. The parabolic cooling towers (factory of electrical power are a typical example of construction, which has a special aggressive environment. The protection of cooling towers is usually achieved through organic coatings. Because of the different environmental impacts on the internal and external side of the cooling tower, a different system of paint application is required. The present study refers to the damages caused by corrosion process. The corrosive environments, the application of this painting, the quality control process, the measures and statistics analysis, and the results were discussed in this study. In the process of quality control the following measurements were taken into consideration: (1 examination of the adhesion with the cross-cut test, (2 examination of the film thickness, and (3 controlling of the pull-off resistance for concrete substrates and paintings. Finally, this study refers to the correlations of measurements, analysis of failures in relation to the quality of repair, and rehabilitation of the cooling tower. Also this study made a first attempt to apply the specific corrosion inhibitors in such a large structure.

  6. Combined preliminary–detailed design of wind turbines

    Directory of Open Access Journals (Sweden)

    P. Bortolotti

    2016-05-01

    Full Text Available This paper is concerned with the holistic optimization of wind turbines. A multi-disciplinary optimization procedure is presented that marries the overall sizing of the machine in terms of rotor diameter and tower height (often termed “preliminary design” with the detailed sizing of its aerodynamic and structural components. The proposed combined preliminary–detailed approach sizes the overall machine while taking into full account the subtle and complicated couplings that arise due to the mutual effects of aerodynamic and structural choices. Since controls play a central role in dictating performance and loads, control laws are also updated accordingly during optimization. As part of the approach, rotor and tower are sized simultaneously, even in this case capturing the mutual effects of one component over the other due to the tip clearance constraint. The procedure, here driven by detailed models of the cost of energy, results in a complete aero-structural design of the machine, including its associated control laws. The proposed methods are tested on the redesign of two wind turbines, a 2.2 MW onshore machine and a large 10 MW offshore one. In both cases, the optimization leads to significant changes with respect to the initial baseline configurations, with noticeable reductions in the cost of energy. The novel procedures are also exercised on the design of low-induction rotors for both considered wind turbines, showing that they are typically not competitive with conventional high-efficiency rotors.

  7. Active Tuned Mass Dampers for Control of In-Plane Vibrations of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Fitzgerald, B.; Basu, Biswajit; Nielsen, Søren R.K.

    2013-01-01

    matrices. The aim of this paper is to determine whether ATMDs could be used to reduce in-plane blade vibrations in wind turbines with better performance than compared with their passive counterparts. A Euler–Lagrangian wind turbine mathematical model based on energy formulation was developed......, centrifugal, and turbulent aerodynamic loadings. Investigations show promising results for the use of ATMDs in the vibration control of wind turbine blades.......This paper investigates the use of active tuned mass dampers (ATMDs) for the mitigation of in-plane vibrations in rotating wind turbine blades. The rotating wind turbine blades with tower interaction represent time-varying dynamical systems with periodically varying mass, stiffness, and damping...

  8. Improving performance and reducing costs of cooling towers

    International Nuclear Information System (INIS)

    Bartz, J.A.

    1992-01-01

    Cooling towers represent a significant capital investment at a steam electric power station. In addition, deficiencies in thermal performance can result in major operating penalties of fuel cost, replacement energy, and capacity addition. This paper summarizes two recent EPRI research projects aimed at reducing thermal performance deficiencies and decreasing installed costs of evaporative cooling towers. First, EPRI Research Project 2113, Cooling Tower Performance Prediction and Improvement, is summarized. This project has resulted in published data sets on the measured thermal performance characteristics of a variety of cooling tower packings, computer codes to predict tower performance, and computer code validation through large-scale tower performance measurements. Principal results are contained in an EPRIGEMS software module, Cooling Tower Advisor. This PC- based software contains a tutorial plus codes to predict tower thermal performance, arranged in a user-friendly format. The second EPRI effort, Research Project 2819-10/11, Fabric Structures for Power Plant Applications, has resulted in designs and costs of large structures with shells constructed of recently-developed fabrics. Primary power plant applications for such structures are the shells of natural draft cooling towers and coal-pile covers. Fabric structures offer low initial cost, acceptable life, and seismic superiority, among other advantages. Detailed conceptual designs and installed cost data are reviewed. 8 refs., 9 figs., 3 tabs

  9. Distinct difference of flaA genotypes of Legionella pneumophila between isolates from bath water and cooling tower water.

    Science.gov (United States)

    Amemura-Maekawa, Junko; Kura, Fumiaki; Chang, Bin; Suzuki-Hashimoto, Atsuko; Ichinose, Masayuki; Endo, Takuro; Watanabe, Haruo

    2008-09-01

    To investigate the genetic difference of Legionella pneumophila in human-made environments, we collected isolates of L. pneumophila from bath water (n = 167) and cooling tower water (n = 128) primarily in the Kanto region in 2001 and 2005. The environmental isolates were serogrouped and sequenced for a target region of flaA. A total of 14 types of flaA genotypes were found: 10 from cooling tower water and nine from bath water. The flaA genotypes of isolates from cooling tower water were quite different from those of bath water.

  10. Aeroelastic optimization of MW wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig Hansen, M.; Zahle, F.

    2011-12-15

    This report contains the results from the Energy Development and Demonstration Project ''Aeroelastic Optimization of MW wind turbine'' (AeroOpt). The project has had the following five Work Packages: 1. Geometric non-linear, anisotropic beam element for HAWC2. 2. Closed-loop eigenvalue analysis of controlled wind turbines. 3. Resonant wave excitation of lateral tower bending modes. 4. Development of next generation aerodynamic design tools. 5. Advanced design and verification of airfoils. The purposes of these Work Packages are briefly described in the Preface and a summary of the results are given in Section 2. Thereafter, the results from each Work Package are described in eight subsequent chapters. (Author)

  11. Lake Michigan Offshore Wind Feasibility Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Boezaart, Arnold [GVSU; Edmonson, James [GVSU; Standridge, Charles [GVSU; Pervez, Nahid [GVSU; Desai, Neel [University of Michigan; Williams, Bruce [University of Delaware; Clark, Aaron [GVSU; Zeitler, David [GVSU; Kendall, Scott [GVSU; Biddanda, Bopi [GVSU; Steinman, Alan [GVSU; Klatt, Brian [Michigan State University; Gehring, J. L. [Michigan State University; Walter, K. [Michigan State University; Nordman, Erik E. [GVSU

    2014-06-30

    project including to: 1) test and validate floating LIDAR technology; 2) collect and access offshore wind data; 3) detect and measure bird and bat activity over Lake Michigan; 4) conduct an over water sound propagation study; 5) prepare and offer a college course on offshore energy, and; 6) collect other environmental, bathometric, and atmospheric data. Desk-top research was performed to select anchorage sites and to secure permits to deploy the buoy. The project also collected and analyzed data essential to wind industry investment decision-making including: deploying highly mobile floating equipment to gather offshore wind data; correlating offshore wind data with conventional on-shore MET tower data; and performing studies that can contribute to the advancement and deployment of offshore wind technologies. Related activities included: • Siting, permitting, and deploying an offshore floating MET facility; • Validating the accuracy of floating LWS using near shoreline cup anemometer MET instruments; • Assessment of laser pulse technology (LIDAR) capability to establish hub height measurement of wind conditions at multiple locations on Lake Michigan; • Utilizing an extended-season (9-10 month) strategy to collect hub height wind data and weather conditions on Lake Michigan; • Investigation of technology best suited for wireless data transmission from distant offshore structures; • Conducting field-validated sound propagation study for a hypothetical offshore wind farm from shoreline locations; • Identifying the presence or absence of bird and bat species near wind assessment facilities; • Identifying the presence or absence of benthic and pelagic species near wind assessment facilities; All proposed project activities were completed with the following major findings: • Floating Laser Wind Sensors are capable of high quality measurement and recordings of wind resources. The WindSentinel presented no significant operational or statistical limitations in

  12. AUTOMATED DEAD-END ULTRAFILTRATION FOR ENHANCED SURVEILLANCE OF LEGIONELLA 2 PNEUMOPHILA AND LEGIONELLA SPP. IN COOLING TOWER WATERS

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.; Leskinen, S.; Kearns, E.; Jones, W.; Miller, R.; Betivas, C.; Kingsley, M.; Lim, D.

    2011-10-10

    Detection of Legionella pneumophila in cooling towers and domestic hot water systems involves concentration by centrifugation or membrane filtration prior to inoculation onto growth media or analysis using techniques such as PCR or immunoassays. The Portable Multi-use Automated Concentration System (PMACS) was designed for concentrating microorganisms from large volumes of water in the field and was assessed for enhancing surveillance of L. pneumophila at the Savannah River Site, SC. PMACS samples (100 L; n = 28) were collected from six towers between August 2010 and April 2011 with grab samples (500 ml; n = 56) being collected before and after each PMACS sample. All samples were analyzed for the presence of L. pneumophila by direct fluorescence immunoassay (DFA) using FITC-labeled monoclonal antibodies targeting serogroups 1, 2, 4 and 6. QPCR was utilized for detection of Legionella spp. in the same samples. Counts of L. pneumophila from DFA and of Legionella spp. from qPCR were normalized to cells/L tower water. Concentrations were similar between grab and PMACS samples collected throughout the study by DFA analysis (P = 0.4461; repeated measures ANOVA). The same trend was observed with qPCR. However, PMACS concentration proved advantageous over membrane filtration by providing larger volume, more representative samples of the cooling tower environment, which led to reduced variability among sampling events and increasing the probability of detection of low level targets. These data highlight the utility of the PMACS for enhanced surveillance of L. pneumophila by providing improved sampling of the cooling tower environment.

  13. Cooling towers for thermal power plants

    International Nuclear Information System (INIS)

    Chaboseau, J.

    1987-01-01

    After a brief recall on cooling towers testing and construction, this paper presents four examples of very large French nuclear power plant cooling towers, and one of an Australian thermal power plant [fr

  14. Mod-5A wind turbine generator program design report. Volume 3: Final design and system description, book 1

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 3, book 1 describes the performance and characteristics of the MOD-5A wind turbine generator in its final configuration. Each subsystem - the rotor, drivetrain, nacelle, tower and foundation is described in detail.

  15. Model-based control of a ballast-stabilized floating wind turbine exposed to wind and waves

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, Soeren

    2013-01-15

    The wind turbine is a commercial product which is competing against other sources of energy, such as coal and gas. This competition drives a constant development to reduce costs and improve efficiency in order to reduce the total cost of the energy. The latest offshore development is the floating wind turbine, for water depths beyond 50 meters where winds are stronger and less turbulent. A floating wind turbine is subject to not only aerodynamics and wind induced loads, but also to hydrodynamics and wave induced loads. In contrast to a bottom fixed wind turbine, the floating structure, the hydrodynamics and the loads change the dynamic behavior of a floating wind turbine. Consequently, conventional wind turbine control cause instabilities on floating wind turbines. This work addresses the control of a floating spar buoy wind turbine, and focuses on the impact of the additional platform dynamics. A time varying control model is presented based on the wind speed and wave frequency. Estimates of the wind speed and wave frequency are used as scheduling variables in a gain scheduled linear quadratic controller to improve the electrical power production while reducing fatigue. To address the problem of negative damped fore-aft tower motion, additional control loops are suggested which stabilize the response of the onshore controller and reduce the impact of the wave induced loads. This research is then extended to model predictive control, to further address wave disturbances. In the context of control engineering, the dynamics and disturbances of a floating wind turbine have been identified and modeled. The objectives of maximizing the production of electrical power and minimizing fatigue have been reached by using advanced methods of estimation and control. (Author)

  16. Prototype bucket foundation for wind turbines - natural frequency estimation

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.

    2006-12-15

    The first full scale prototype bucket foundation for wind turbines has been installed in October 2002 at Aalborg University offshore test facility in Frederikshavn, Denmark. The suction caisson and the wind turbine have been equipped with an online monitoring system, consisting of 15 accelerometers and a real-time data-acquisition system. The report concerns the in service performance of the wind turbine, with focus on estimation of the natural frequencies of the structure/foundation. The natural frequencies are initially estimated by means of experimental Output-only Modal analysis. The experimental estimates are then compared with numerical simulations of the suction caisson foundation and the wind turbine. The numerical model consists of a finite element section for the wind turbine tower and nacelle. The soil-structure interaction of the soil-foundation section is modelled by lumped-parameter models capable of simulating dynamic frequency dependent behaviour of the structure-foundation system. (au)

  17. Performance characteristics of a shower cooling tower

    International Nuclear Information System (INIS)

    Qi Xiaoni; Liu Zhenyan; Li Dandan

    2007-01-01

    This study was prompted by the need to design towers for applications in which, due to salt deposition on the packing and subsequent blockage, the use of tower packing is not practical. In contrast to conventional cooling towers, the cooling tower analyzed in this study is void of fill. By means of efficient atomization nozzles, a shower cooling tower (SCT) is possible to be applied in industry, which, in terms of water cooling, energy saving and equipment investing, is better than conventional packed cooling towers. However, no systematic thermodynamic numerical method could be found in the literature up to now. Based on the kinetic model and mass and heat transfer model, this paper has developed a one dimensional model for studying the motional process and evaporative cooling process occurring at the water droplet level in the SCT. The finite difference approach is used for three motional processes to obtain relative parameters in each different stage, and the possibility of the droplets being entrained outside the tower is fully analyzed. The accuracy of this model is checked by practical operational results from a full scale prototype in real conditions, and some exclusive factors that affect the cooling characteristics for the SCT are analyzed in detail. This study provides the theoretical foundation for practical application of the SCT in industry

  18. Quantifying the hurricane risk to offshore wind turbines.

    Science.gov (United States)

    Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J; Grossmann, Iris; Apt, Jay

    2012-02-28

    The U.S. Department of Energy has estimated that if the United States is to generate 20% of its electricity from wind, over 50 GW will be required from shallow offshore turbines. Hurricanes are a potential risk to these turbines. Turbine tower buckling has been observed in typhoons, but no offshore wind turbines have yet been built in the United States. We present a probabilistic model to estimate the number of turbines that would be destroyed by hurricanes in an offshore wind farm. We apply this model to estimate the risk to offshore wind farms in four representative locations in the Atlantic and Gulf Coastal waters of the United States. In the most vulnerable areas now being actively considered by developers, nearly half the turbines in a farm are likely to be destroyed in a 20-y period. Reasonable mitigation measures--increasing the design reference wind load, ensuring that the nacelle can be turned into rapidly changing winds, and building most wind plants in the areas with lower risk--can greatly enhance the probability that offshore wind can help to meet the United States' electricity needs.

  19. Atmospheric emissions from power plant cooling towers

    International Nuclear Information System (INIS)

    Micheletti, W.

    2006-01-01

    Power plant recirculated cooling systems (cooling towers) are not typically thought of as potential sources of air pollution. However, atmospheric emissions can be important considerations that may influence cooling tower design and operation. This paper discusses relevant U.S. environmental regulations for potential atmospheric pollutants from power plant cooling towers, and various methods for estimating and controlling these emissions. (orig.)

  20. Assessment of cooling tower impact

    International Nuclear Information System (INIS)

    1986-01-01

    This guideline describes the state of the art of the meteorological impact of wet cooling towers that are about 80 m to 170 m high, and have a waste heat power in the range of 1000 MW and 2500 MW. The physical processes occurring in the lowest layer of the atmosphere and their impact in the dispersion of cooling tower emissions are represented. On the basis of these facts, the impact on weather or climate in the vicinity of a high wet cooling tower is estimated. Thereby the results of the latest investigations (observations, measurements, and modeling) on the different locations of plants as well as their different power and construction types are taken into consideration. (orig.) [de

  1. Modern Control Design for Flexible Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Wright, A. D.

    2004-07-01

    Control can improve energy capture and reduce dynamic loads in wind turbines. In the 1970s and 1980s, wind turbines used classical control designs to regulate power and speed. The methods used, however, were not always successful. Modern turbines are larger, mounted on taller towers, and more dynamically active than their predecessors. Control systems to regulate turbine power and maintain stable, closed-loop behavior in the presence of turbulent wind inflow will be critical for these designs. This report applies modern state-space control design methods to a two-bladed teetering hub upwind machine at the National Wind Technology Center (NWTC), which is managed by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado. The design objective is to regulate turbine speed and enhance damping in several low-damped flexible modes of the turbine. Starting with simple control algorithms based on linear models, complexity is added incrementally until the desired performance is firmly established.

  2. Equivalent models of wind farms by using aggregated wind turbines and equivalent winds

    International Nuclear Information System (INIS)

    Fernandez, L.M.; Garcia, C.A.; Saenz, J.R.; Jurado, F.

    2009-01-01

    As a result of the increasing wind farms penetration on power systems, the wind farms begin to influence power system, and therefore the modeling of wind farms has become an interesting research topic. In this paper, new equivalent models of wind farms equipped with wind turbines based on squirrel-cage induction generators and doubly-fed induction generators are proposed to represent the collective behavior on large power systems simulations, instead of using a complete model of wind farms where all the wind turbines are modeled. The models proposed here are based on aggregating wind turbines into an equivalent wind turbine which receives an equivalent wind of the ones incident on the aggregated wind turbines. The equivalent wind turbine presents re-scaled power capacity and the same complete model as the individual wind turbines, which supposes the main feature of the present equivalent models. Two equivalent winds are evaluated in this work: (1) the average wind from the ones incident on the aggregated wind turbines with similar winds, and (2) an equivalent incoming wind derived from the power curve and the wind incident on each wind turbine. The effectiveness of the equivalent models to represent the collective response of the wind farm at the point of common coupling to grid is demonstrated by comparison with the wind farm response obtained from the detailed model during power system dynamic simulations, such as wind fluctuations and a grid disturbance. The present models can be used for grid integration studies of large power system with an important reduction of the model order and the computation time

  3. Bats and wind turbines : pre-siting and pre-construction survey protocols

    Energy Technology Data Exchange (ETDEWEB)

    Lausen, C.; Baerwald, E.; Gruver, J.; Barclay, R. [Calgary Univ., AB (Canada)

    2008-05-15

    Studies have shown that a number of bats are killed by moving wind turbine blades at wind farms throughout North America. The studies have shown that over 80 per cent of the fatalities involve migratory bat species. Hoary bats, eastern red bats, and silver-haired bats dominate the fatalities during the fall migration period. Fatality rates vary among wind energy developments. Some data suggest that fatalities are higher on nights with lower wind speeds, and increased fatalities have been associated with taller wind turbines. This report outlined pre-construction survey requirements for preventing bat fatalities at wind power plants. A pre-construction survey was recommended to achieve a representative sampling of bat activity and determine the relative risk to bats. The study suggested that monitoring data from locations across the province should be pooled to provide a better understanding of the landscape-scale patterns of bat migration. Monitoring for bats should be conducted continuously due to the sporadic nature of peaks in bat activity, the influence of temperature, moon phase, and weather variables. Sampling techniques for acoustic detection, radar tracking, and mist-netting should be implemented to determine the abundance of susceptible species and the location of migration routes. All existing meteorological towers should be used as sampling stations with bat detectors installed at ground level and near the top of the tower. Additional detector stations should be distributed throughout the wind resource area. Specialized anabat microphones should be calibrated to record bat activity. Acoustic data should be presented as total bat passes and mean passes per night and matched with corresponding meteorological data. It was concluded that pre-construction monitoring data should be gathered and made available for collaborative and cumulative research efforts. 28 refs., 1 fig.

  4. Flicker Mitigation by Individual Pitch Control of Variable Speed Wind Turbines With DFIG

    DEFF Research Database (Denmark)

    Zhang, Yunqian; Chen, Zhe; Hu, Weihao

    2014-01-01

    generatorto investigate the flicker emission and mitigation issues. An individual pitch control (IPC) strategy is proposed to reduce the flicker emission at different wind speed conditions. The IPC scheme is proposed and the individual pitch controller is designed according to the generator active power...... and the azimuth angle of the wind turbine. The simulations are performed on the NREL (National Renewable Energy Laboratory) 1.5-MW upwind reference wind turbine model. Simulation results show that damping the generator active power by IPC is an effective means for flicker mitigation of variable speed wind......Due to the wind speed variation, wind shear and tower shadow effects, grid connected wind turbines are the sources of power fluctuations which may produce flicker during continuous operation. This paper presents a model of an MW-level variable-speed wind turbine with a doubly fed induction...

  5. Biofouling control of industrial seawater cooling towers

    KAUST Repository

    Albloushi, Mohammed

    2017-11-01

    The use of seawater in cooling towers for industrial applications has much merit in the Gulf Cooperation Council countries due to the scarcity and availability of fresh water. Seawater make-up in cooling towers is deemed the most feasible because of its unlimited supply in coastal areas. Such latent-heat removal with seawater in cooling towers is several folds more efficient than sensible heat extraction via heat exchangers. Operational challenges such as scaling, corrosion, and biofouling are a major challenge in conventional cooling towers, where the latter is also a major issue in seawater cooling towers. Biofouling can significantly hamper the efficiency of cooling towers. The most popular methods used in cooling treatment to control biofouling are disinfection by chlorination. However, the disadvantages of chlorination are formation of harmful disinfection byproducts in the presence of high organic loading and safety concerns in the storage of chlorine gas. In this study, the research focuses on biofouling control in seawater cooling towers by investigating two different approaches. The first strategy addresses the use of alternative oxidants (i.e. ozone micro-bubbles and chlorine dioxide) in treatment of cooling towers. The second strategy investigates removing nutrients in seawater using granular activated carbon filter column and ultrafiltration to prevent the growth of microorganisms. Laboratory bench-scale tests in terms of temperature, cycle of concentration, dosage, etc. indicated that, at lower oxidant dosages (total residual oxidant (TRO) equivalent = 0.1 mg/l Cl2), chlorine dioxide had a better disinfection effect than chlorine and ozone. The performance of oxidizing biocides at pilot scale, operating at assorted conditions, showed that for the disinfectants tested, ozone could remove 95 % bioactivity of total number of bacteria and algae followed by chlorine dioxide at 85%, while conventional chlorine dosing only gave 60% reduction in bioactivities

  6. The effect of the Sep wind park near Oosterbierum, Friesland, The Netherlands, on birds

    International Nuclear Information System (INIS)

    Winkelman, J.E.

    1992-01-01

    The study concerns 1984-1991. The wind park consists of 18 three-bladed 300 kW horizontal axis wind turbines of 35 meters height, and a rotor diameter of 30 meters, seven meteorological towers, and three cluster and control buildings. Aspects studied included disturbance of breeding, resting or feeding, and migrating birds, behavior of birds approaching the wind turbines during the day and night, and bird victims due to collision with the wind turbines and the meteorological towers. The flight behavior of birds approaching the wind park system during daylight is also dealt with. For at least a fifth of the observations it was noted whether the birds passing within 100 meters distance of a turbine showed a reaction or not. The proportion of the reactions was related to the wind park in operation or not in operation, and to the distance between the wind turbines, species, flight height, the passing distance, wind direction and wind force. Secondly the flight path of birds approaching the wind park from eastern directions during daylight (real autumn migration) and from southern directions during late afternoon (flights of gulls to night roosts) was studied in detail. Significantly more reactions (11-18%) were recorded with the wind park fully operational compared to the wind park not operational (2%). In total 2203 flight paths of birds approaching the wind park were recorded during 151 hours of observation. The test results showed that a passing distance of less or more than 100 meters of the nearest wind turbine did not affect the proportion of reactions. Several reaction types and combinations were noted, varying from gradual and calm reactions (circa 75%), and panic reactions, occurring just before or while passing the wind turbines. The reactions are shift in the flight path in the horizontal plane (30%), shift in the flight path in the vertical plane (14%), one passing attempt (87%), an accelerated wing beat (14%), an alteration of the angle of the body (21%)

  7. STUDY ON PERFORMANCE OF 21M 132kV TRANSMISSION TOWER WITH MEDIUM WIND INTENSITY

    OpenAIRE

    V. LAKSHMI; A. RAJAGOPALA RAO

    2012-01-01

    Electric Power is today playing an increasingly important role in the life of the community. In the electric power system the production and transmission of power are two predominant factors. For the purpose of transmission of electricity towers are the main medium with some wires at required distances and altitudes. The remotehydroelectric power plants have given rise to the need for extra high voltage. Prior to 1950, 150 kV electric transmission lines were considered and still higher voltag...

  8. Surprisingly low frequency attenuation effects in long tubes when measuring turbulent fluxes at tall towers

    DEFF Research Database (Denmark)

    Ibrom, Andreas; Brændholt, Andreas; Pilegaard, Kim

    2016-01-01

    The eddy covariance technique relies on the fast and accurate measurement of gas concentration fluctuations. While for some gasses robust and compact sensors are available, measurement of, e.g., non CO2 greenhouse gas fluxes is often performed with sensitive equipment that cannot be run on a tower...... without massively disturbing the wind field. To measure CO and N2O fluxes, we installed an eddy covariance system at a 125 m mast, where the gas analyser was kept in a laboratory close to the tower and the sampling was performed using a 150 m long tube with a gas intake at 96 m height. We investigated...... by reducing both the water vapour dilution correction and the cross sensitivity effects on the N2O and CO flux measurements. Here we present the set-up of the concentration step change experiment and its results and compare them with recently developed theories for the behaviour of gases in turbulent tube...

  9. Importance of Dynamic Inflow Model Predictive Control of Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Knudsen, Torben; Overgaard, Anders

    2015-01-01

    The efficiency of including dynamic inflow in the model based design of wind turbine controller has been discussed for many years in the wind energy community with out getting to a safe conclusion. This paper delivers a good argument in favor of including dynamic inflow. The main contributions...... pronounces. For this the well accepted NREL 5MW reference turbine simulated with FAST is used. The main result is a reduction in tower fatigue load at 22% while power error, rotor speed error, generator torque and pitch rate is improved from 2 to 33%....

  10. Dependence of offshore wind turbine fatigue loads on atmospheric stratification

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.; Ott, Søren

    2014-01-01

    The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representi...... conditions. In general, impact of ABL stratification is clearly seen on wake affected inflow cases for both blade and tower fatigue loads. However, the character of this dependence varies significantly with the type of inflow conditions – e.g. single wake inflow or multiple wake inflow....

  11. Optimization of wind turbine rotors

    Energy Technology Data Exchange (ETDEWEB)

    Nygaard, Tor Anders

    1999-07-01

    The Constrained Steepest Descent method has been applied to the optimization of wind turbine rotors through the development of a numerical model. The model consists of an optimization kernel, an aerodynamic model, a structural dynamic model of a rotating beam, and a cost model for the wind turbine. The cost of energy is minimized directly by varying the blade design, the rotational speed and the resulting design of the drive-train and tower. The aerodynamic model is a combination of a fast engineering model based on strip-theory and two and three-dimensional Euler solvers. The two-dimensional Euler solver is used for generation of pre-stall airfoil data. Comparisons with experimental data verify that the engineering model effectively approximates non-stalled flow, except at the blade tip. The three-dimensional Euler solver is in good agreement with the experimental data at the tip, and is therefore a useful supplement for corrections of the tip-loss model, and evaluation of an optimized design. The structural dynamic model evaluates stresses and deformations for the blade. It is based on constitutive relations for a slender beam that are solved with the equations of motions using a finite-difference method. The cost model evaluates the design change of the wind turbine and the resulting costs that occur when a change in blade design modifies the blade mass and the overall forces. The cost model is based on engineering design rules for the drive-train and tower. The model was applied using a Danish 600 kW wind turbine as a reference. Two rotors were optimized using traditional NACA airfoils and a new low-lift airfoil family developed specifically for wind turbine purposes. The cost of energy decreased four percent for the NACA rotor, and seven percent for the low-lift rotor. Optimizations with a high number of degrees of freedom show that a designer has considerable flexibility in choosing some primary parameters such as rated power and rotor diameter, if the rest

  12. Selection of DC/DC converter for offshore wind farms with MVDC power collection

    DEFF Research Database (Denmark)

    Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

    2017-01-01

    Four DC/DC converters are analyzed and compared with respects to availability, efficiency, ratings, repair costs and power density. Intended application is offshore wind farms with MVDC power collection. The selected topology is a new series resonant converter, which offers 99% efficiency across...

  13. Concept design and coupled dynamic response analysis on 6-MW spar-type floating offshore wind turbine

    Science.gov (United States)

    Meng, Long; Zhou, Tao; He, Yan-ping; Zhao, Yong-sheng; Liu, Ya-dong

    2017-10-01

    Tower, Spar platform and mooring system are designed in the project based on a given 6-MW wind turbine. Under wind-induced only, wave-induced only and combined wind and wave induced loads, dynamic response is analyzed for a 6-MW Spar-type floating offshore wind turbine (FOWT) under operating conditions and parked conditions respectively. Comparison with a platform-fixed system (land-based system) of a 6-MW wind turbine is carried out as well. Results demonstrate that the maximal out-of-plane deflection of the blade of a Spar-type system is 3.1% larger than that of a land-based system; the maximum response value of the nacelle acceleration is 215% larger for all the designed load cases being considered; the ultimate tower base fore-aft bending moment of the Spar-type system is 92% larger than that of the land-based system in all of the Design Load Cases (DLCs) being considered; the fluctuations of the mooring tension is mainly wave-induced, and the safety factor of the mooring tension is adequate for the 6-MW FOWT. The results can provide relevant modifications to the initial design for the Spar-type system, the detailed design and model basin test of the 6-MW Spar-type system.

  14. The WRF model forecast-derived low-level wind shear climatology over the United States great plains

    Energy Technology Data Exchange (ETDEWEB)

    Storm, B. [Wind Science and Engineering Research Center, Texas Tech University, Lubbock, TX (United States); Basu, S. [Atmospheric Science Group, Department of Geosciences, Texas Tech University, Lubbock, TX (United States)

    2010-07-01

    For wind resource assessment projects, it is common practice to use a power-law relationship (U(z) {proportional_to} z{sup {alpha}}) and a fixed shear exponent ({alpha} = 1/7) to extrapolate the observed wind speed from a low measurement level to high turbine hub-heights. However, recent studies using tall-tower observations have found that the annual average shear exponents at several locations over the United States Great Plains (USGP) are significantly higher than 1/7. These findings highlight the critical need for detailed spatio-temporal characterizations of wind shear climatology over the USGP, where numerous large wind farms will be constructed in the foreseeable future. In this paper, a new generation numerical weather prediction model - the Weather Research and Forecasting (WRF) model, a fast and relatively inexpensive alternative to time-consuming and costly tall-tower projects, is utilized to determine whether it can reliably estimate the shear exponent and the magnitude of the directional shear at any arbitrary location over the USGP. Our results indicate that the WRF model qualitatively captures several low-level wind shear characteristics. However, there is definitely room for physics parameterization improvements for the WRF model to reliably represent the lower part of the atmospheric boundary layer. (author)

  15. Modality analysis of anchored ion exchange tower using Ansys

    International Nuclear Information System (INIS)

    Li Liang; Lei Zeyong

    2008-01-01

    Ion exchange towers are exposed to serious damage in the event of earthquakes. It is very necessary to study the seismic resistance of ion exchange tower. A finite element model of anchored ion exchange tower was made by Ansys. The first 10 ranks of inherent frequencies were made out, and three-dimensional main vibratory model figures were drawn out. The maximal stress along x-axis and y-axis and the main displacement were found at the bottom part of the wall of tower junction with the pillars. It is concluded that the breakage of tower wall easily occurs at the bottom part of the wall of tower junction with the pillars. Therefore, it is very important to reinforce the junction of the tower body, and the strengthening plate should lie near the bottom of wall. (authors)

  16. Stochastic Prediction of Wind Generating Resources Using the Enhanced Ensemble Model for Jeju Island’s Wind Farms in South Korea

    Directory of Open Access Journals (Sweden)

    Deockho Kim

    2017-05-01

    Full Text Available Due to the intermittency of wind power generation, it is very hard to manage its system operation and planning. In order to incorporate higher wind power penetrations into power systems that maintain secure and economic power system operation, an accurate and efficient estimation of wind power outputs is needed. In this paper, we propose the stochastic prediction of wind generating resources using an enhanced ensemble model for Jeju Island’s wind farms in South Korea. When selecting the potential sites of wind farms, wind speed data at points of interest are not always available. We apply the Kriging method, which is one of spatial interpolation, to estimate wind speed at potential sites. We also consider a wind profile power law to correct wind speed along the turbine height and terrain characteristics. After that, we used estimated wind speed data to calculate wind power output and select the best wind farm sites using a Weibull distribution. Probability density function (PDF or cumulative density function (CDF is used to estimate the probability of wind speed. The wind speed data is classified along the manufacturer’s power curve data. Therefore, the probability of wind speed is also given in accordance with classified values. The average wind power output is estimated in the form of a confidence interval. The empirical data of meteorological towers from Jeju Island in Korea is used to interpolate the wind speed data spatially at potential sites. Finally, we propose the best wind farm site among the four potential wind farm sites.

  17. Asbestos in cooling-tower waters. Final report

    International Nuclear Information System (INIS)

    Lewis, B.A.G.

    1979-03-01

    Water discharges from cooling towers constructed with asbestos fill were found to contain chrysotile--asbestos fibers at concentrations as high as 10 8 fibers/liter. The major source of these fibers, appears to be the components of the towers rather than the air drawn through the towers or the makeup water taken into the towers. Suggested mechanisms for the release of chrysotile fibers from cooling-tower fill include freeze-thaw cycles and dissolution of the cement due to acidic components of the circulating water. Ash- or other material-settling ponds were found to reduce asbestos-fiber concentrations in cooling-tower effluent. The literature reviewed did not support the case for a causal relationship between adverse human health effects and drinking water containing on the order of 10 6 chrysotile--asbestos fibers/liter; for this and other reasons, it is not presently suggested that the use of asbestos fill be discontinued. However, caution and surveillance are dictated by the uncertainties in the epidemiological studies, the absence of evidence for a safe threshold concentration in water, and the conclusive evidence for adverse effects from occupational exposure. It is recommended that monitoring programs be carried out at sites where asbestos fill is used; data from such programs can be used to determine whether any mitigative measures should be taken. On the basis of estimates made in this study, monitoring for asbestos in drift from cooling towers does not appear to be warranted

  18. System Identification of Wind Turbines for Structural Health Monitoring

    DEFF Research Database (Denmark)

    Perisic, Nevena

    Structural health monitoring is a multi-disciplinary engineering field that should allow the actual wind turbine maintenance programmes to evolve to the next level, hence increasing safety and reliability and decreasing turbines downtime. The main idea is to have a sensing system on the structure...... cases are considered, two practical problems from the wind industry are studied, i.e. monitoring of the gearbox shaft torque and the tower root bending moments. The second part of the thesis is focused on the influence of friction on the health of the wind turbine and on the nonlinear identification...... that monitors the system responses and notifies the operator when damages or degradations have been detected. However, some of the response signals that contain important information about the health of the wind turbine components cannot be directly measured, or measuring them is highly complex and costly...

  19. Optimal Control of a Ballast-Stabilized Floating Wind Turbine

    DEFF Research Database (Denmark)

    Christiansen, Søren; Knudsen, Torben; Bak, Thomas

    2011-01-01

    Offshore wind energy capitalizes on the higher and less turbulent wind speeds at sea. The use of floating structures for deeper waters is being explored. The control objective is a tradeoff between power capture and fatigue, especially that produced by the oscillations caused by the reduced...... structural stiffness of a floating installation in combination with a coupling between the fore–aft motion of the tower and the blade pitch. To address this problem, the present paper models a ballast-stabilized floating wind turbine, and suggests a linear quadratic regulator (LQR) in combination with a wind...... estimator and a state observer. The results are simulated using aero elastic code and analysed in terms of damage equivalent loads. When compared to a baseline controller, this controller clearly demonstrates better generator speed and power tracking while reducing fatigue loads....

  20. Mastering the power of wind

    International Nuclear Information System (INIS)

    Stiegel, J.

    1999-01-01

    In this paper the author deals with environmental aspects use of fossil fuels for the energy production. As a way for our planet to get back to a normal and ecologically balanced system the fossil fuels reduction and their replacement by renewable racecourses is recommended. Energetic potential of flowing sun, wind and tidal waves as power resources is discussed. The natural ecological resources are best utilised in the United States where the installed wind power output is 1600 MW. With 360 MW installed output in 1991 the Denmark took lead among European countries in utilising the wind power. The most dynamic power plant development among the European Union countries was recorded in Germany, where the installed power output of the wind power plants is 632 MW, i.e. i.e. 11.5 times higher compared to 55 MW in 1991. The economy of wind power in Germany and in Slovakia is compared. In Slovakia with annual 200 000 kWh power generation annually and the present kWh purchase price guarantee the rate of return of 10 million slovak crowns investment into a wind power plant project is in 100 years. Although the first wind power plants have already been built in the Zahorie, Kremnicke Bane, and Secovce regions, the wind exploitation status in Slovakia is still limping. According to professionals, the wind conditions in Slovakia are not ideal, but sufficient for a supplementary wind power plant system, that can be quite motivating especially for villages. Mount Chopok or mount Krizna are ideal sites to erect the three-blade tower with respect to wind speed. And also the anticipated Kremnicke vrchy site is worth considering. (author)

  1. Progressive innovations in applying of wind energy

    International Nuclear Information System (INIS)

    Yershina, Ainakul K.; Yershin, Chingiz Sh.

    2013-01-01

    The article presents the current design of a laboratory model, the so-called model of vertical-axis wind turbine component. Construction work carried out, and then made a valid laboratory model of cross-sectional area S = 0,64 m 2 , which can operate as a conventional Darya, and in the mode of our constructive solutions. The tower that supports the wind turbine installed in the vertical position of the shaft 2, each of which is connected with only one blade and working with their current generator. The shafts are separated by a bearing and can operate autonomously, independently of each other. The mechanical energy of rotation is transferred to two different power generators, ie Each shaft works on his generator. Electricity generated by them is summarized. Thus, the feature of this design is the increased removal of wind energy in two independent working trees with the same swept area. Therefore, effective value of wind energy usage efficiency may be increased to 0.7 in case of high production culture.Vertical - axis turbine component has a special lock that supports the angle between the furs 180 °. Key words: wind turbine Darrieus, shaft, generator current, power, wind speed, blade

  2. Progressive innovations in applying of wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Yershina, Ainakul K. [Kazakh State Women Pedogogical University, Almaty (Kazakhstan); Yershin, Chingiz Sh. [Kazakh Natio nal University named by al - Farabi, Almaty (Kazakhstan)

    2013-07-01

    The article presents the current design of a laboratory model, the so-called model of vertical-axis wind turbine component. Construction work carried out, and then made a valid laboratory model of cross-sectional area S = 0,64 m{sup 2} , which can operate as a conventional Darya, and in the mode of our constructive solutions. The tower that supports the wind turbine installed in the vertical position of the shaft 2, each of which is connected with only one blade and working with their current generator. The shafts are separated by a bearing and can operate autonomously, independently of each other. The mechanical energy of rotation is transferred to two different power generators, ie Each shaft works on his generator. Electricity generated by them is summarized. Thus, the feature of this design is the increased removal of wind energy in two independent working trees with the same swept area. Therefore, effective value of wind energy usage efficiency may be increased to 0.7 in case of high production culture.Vertical - axis turbine component has a special lock that supports the angle between the furs 180 °. Key words: wind turbine Darrieus, shaft, generator current, power, wind speed, blade.

  3. Hard bottom substrate monitoring Horns Rev offshore wind farm. Annual status report 2003

    Energy Technology Data Exchange (ETDEWEB)

    Leonhard, S.B.; Pedersen, John

    2004-05-15

    Elsam and Eltra built the offshore demonstration wind farm at Horns Rev in the North Sea. Elsam is the owner and is responsible for the operation of the wind farm. Eltra is responsible for the connection of the wind farm to the national onshore grid. In the summer months of 2002, Elsam constructed the world's largest offshore wind farm off the Danish west coast. The wind farm is sited 14-20 km into the North Sea, west of Blaevands Huk. The first wind turbine was erected in May 2002 and the last wind turbine tower of a total of 80 was in place by August 2002. The construction work was completed with the last connecting cables sluiced down in September 2002. All the wind turbines were in production by December 2002. The expected impact of the wind farm will primarily be an alternation of habitats due to the introduction of hard bottom substrates as wind turbine towers and scour protections. A continuous development in the epifouling communities will be expected together with an introduction of new or alien species in the area. The indigenous benthic community in the area of Horns Rev can be characterised by infauna species belonging to the Goniadella-Spisula community. This community is typical of sandbanks in the North Sea area, although communities in such areas are very variable and site-specific. Character species used as indicators for environmental changes in the Horns Rev area are the bristle worms Goniadella bobretzkii, Ophelia borealis, Psione remota and Orbinia sertulata and the mussels Goodallia triangularis and Spisula solida. In connection with the implementation of the monitoring programme concerning the ecological impact of the introduction of hard substrate related to the Horns Rev Wind Farm, surveys on hard bottom substrate was conducted in March 2003 and in September 2003. This report describes the first year results of surveys on hard substrate after the completion of the offshore wind farm at Horns Rev. (au)

  4. Data report: the wake of a horizontal-axis wind turbine model, measurements in uniform approach flow and in a simulated atmospheric boundary layer

    NARCIS (Netherlands)

    Talmon, A.M.

    1985-01-01

    Wake effects will cause power loss when wínd turbínes are grouped in so called wind turbine parks. Wind tunnel measurements of the wake of a wind turbíne model are conducted in order to refine calculatíons of wake effects. Wake effects caused by tower and nacelle are studied in uniform flow. Wake

  5. Real time monitoring of slope condition for transmission tower safety in Kenyir, Malaysia

    Science.gov (United States)

    Omar, R. C.; Ismail, A.; Khalid, N. H. N.; Din, N. M.; Hussain, H.; Jamaludin, M. Z.; Abdullah, F.; Arazad, A. Z.; Yusop, H.

    2013-06-01

    The Malaysia national electricity grid traverses throughout the nation over urban and rural areas including mountainous terrain. A major number of the transmission towers have been in existence for over 40 years and some traversed through very remote and high altitude areas like the Titiwangsa range that forms the backbone of the Malay Peninsula. This paper describes the instrumentation and real time monitoring in a transmission tower site in Kenyir, a hilly terrain in the East Coast of Malaysia. The site itself which is between 300-500m above sea level is deep in the rainforest area of Kenyir. The site and surrounding areas has been identified with signs of slope failure. A design concern is the real time slope monitoring sensors reliability and data integrity from the remote area with potential interference to the electronics equipment from the power line. The monitoring system comprised of an automated system for collecting and reporting field monitoring data. The instruments collect readings and transmit real time through GSM to the monitoring office over designated intervals. This initiative is a part of a project on developing an early warning system for monitoring landslide hazards at selected transmission towers. This paper reviews the various instrumentation used and challenges faced and the output received for slope movement warnings.

  6. Real time monitoring of slope condition for transmission tower safety in Kenyir, Malaysia

    International Nuclear Information System (INIS)

    Omar, R C; Ismail, A; Khalid, N H N; Din, N M; Hussain, H; Jamaludin, M Z; Abdullah, F; Arazad, A Z; Yusop, H

    2013-01-01

    The Malaysia national electricity grid traverses throughout the nation over urban and rural areas including mountainous terrain. A major number of the transmission towers have been in existence for over 40 years and some traversed through very remote and high altitude areas like the Titiwangsa range that forms the backbone of the Malay Peninsula. This paper describes the instrumentation and real time monitoring in a transmission tower site in Kenyir, a hilly terrain in the East Coast of Malaysia. The site itself which is between 300–500m above sea level is deep in the rainforest area of Kenyir. The site and surrounding areas has been identified with signs of slope failure. A design concern is the real time slope monitoring sensors reliability and data integrity from the remote area with potential interference to the electronics equipment from the power line. The monitoring system comprised of an automated system for collecting and reporting field monitoring data. The instruments collect readings and transmit real time through GSM to the monitoring office over designated intervals. This initiative is a part of a project on developing an early warning system for monitoring landslide hazards at selected transmission towers. This paper reviews the various instrumentation used and challenges faced and the output received for slope movement warnings.

  7. ''Novel'' types of cooling towers for the power industry

    International Nuclear Information System (INIS)

    Mikyska, L.

    1991-01-01

    New types of cooling towers are beginning to be used abroad for the cooling circuits of nuclear power plants employing power generation units rated at 1,300 to 1,400 MW. These so-called water recovery cooling towers make use of natural draught without a droplet section. They are actually upgraded designs which were built in Europe as far back as 70 years ago. Because of the unsuitable materials then employed, these cooling towers fell into oblivion. Today, however, they are undergoing a renaissance. An upgraded design of these towers is described and compared with existing cooling towers with a droplet section. The feasibility of using these towers in Czechoslovak conditions is considered. (author)

  8. Utgrunden off-shore wind farm - Measurements of underwater noise

    International Nuclear Information System (INIS)

    Lindell, Hans

    2003-07-01

    Airicole, GE Wind Energy and SEAS/Energi E2 have initiated this project in order to achieve a better understanding on how offshore based wind farms effect the underwater noise. The main reason is to gain knowledge on how marine wildlife could be effected by this kind of installation. The measurements were performed at Utgrunden wind farm that is situated at the reef Utgrunden on the Swedish southeast coast. The farm consists of seven 1,5 MW turbines. Three hydrophones registered the underwater sound and four accelerometers the tower vibrations. The measurement campaign was conducted during a period from November 2002 to February 2003. The objectives with this project is to answer the following issues and its results are: 1. What is the character of sound from a single power station? - The turbines radiate sound mainly at a few dominating frequencies from 30 Hz up to 800 Hz. At frequencies below 3 Hz no contribution from the turbines can be detected due to the high background level from the waves and the low tower vibration level. 2. What are the sound generating mechanisms in the turbine? - Gearbox mesh frequency vibrations that are transmitted via the tower structure and radiated out to the water mainly generate the sound. Airborne blade sound is effectively dampened in the transition from air to water. 3. How does the sound attenuate with increasing distance at different frequencies? - The average attenuation per doubled distance for frequencies between 31 Hz and 722 Hz is approximately 4 dB in the measured positions. No clear frequency dependence could be found. 4. How does the sound pressure level vary with increasing wind speed? - With increasing wind speed, the sound pressure level increases and the dominating frequencies move upward due to increasing turbine rotational speed. 5. How does sound from different power stations interfere with each other and influence the over all sound image? - No clear tendencies of interference could be observed in this study

  9. Newton slopes for Artin-Schreier-Witt towers

    DEFF Research Database (Denmark)

    Davis, Christopher; Wan, Daqing; Xiao, Liang

    2016-01-01

    We fix a monic polynomial f(x)∈Fq[x] over a finite field and consider the Artin-Schreier-Witt tower defined by f(x); this is a tower of curves ⋯→Cm→Cm−1→⋯→C0=A1, with total Galois group Zp. We study the Newton slopes of zeta functions of this tower of curves. This reduces to the study of the Newton...... slopes of L-functions associated to characters of the Galois group of this tower. We prove that, when the conductor of the character is large enough, the Newton slopes of the L-function form arithmetic progressions which are independent of the conductor of the character. As a corollary, we obtain...

  10. Coupled-Mode Flutter of Wind Turbines and its Suppression Using Torsional Viscous Damper

    DEFF Research Database (Denmark)

    Zhang, Zili; Chen, Bei; Nielsen, Søren R. K.

    2017-01-01

    The trend towards lighter and more flexible blades may lead to aeroelastic instability of wind turbines under certain circumstances, resulting in rapid destructive failure or limit-cycle oscillations of the structural components. For pitch-regulated wind turbines, classical flutter is believed...... between blade vibrations with tower and drivetrain motions are also considered, making this model capable for coupled-mode flutter analysis of a complete wind turbine system. The parameters of the model have been calibrated to the DTU 10MW wind turbine, and the critical flutter speed of the rotor is shown...... to be about 1.6 times its nominal rotational speed. A novel torsional viscous damper is then proposed to suppress torsional blade vibration and to enhance flutter stability of wind turbines....

  11. Next Generation Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Cheraghi, S. Hossein [Western New England Univ., Springfield, MA (United States); Madden, Frank [FloDesign Wind Turbine Corp., Waltham, MA (United States)

    2012-09-01

    The goal of this collaborative effort between Western New England University's College of Engineering and FloDesign Wind Turbine (FDWT) Corporation to wok on a novel areodynamic concept that could potentially lead to the next generation of wind turbines. Analytical studies and early scale model tests of FDWT's Mixer/Ejector Wind Turbine (MEWT) concept, which exploits jet-age advanced fluid dynamics, indicate that the concept has the potential to significantly reduce the cost of electricity over conventional Horizontal Axis Wind Turbines while reducing land usage. This project involved the design, fabrication, and wind tunnel testing of components of MEWT to provide the research and engineering data necessary to validate the design iterations and optimize system performance. Based on these tests, a scale model prototype called Briza was designed, fabricated, installed and tested on a portable tower to investigate and improve the design system in real world conditions. The results of these scale prototype efforts were very promising and have contributed significantly to FDWT's ongoing development of a product scale wind turbine for deployment in multiple locations around the U.S. This research was mutually beneficial to Western New England University, FDWT, and the DOE by utilizing over 30 student interns and a number of faculty in all efforts. It brought real-world wind turbine experience into the classroom to further enhance the Green Engineering Program at WNEU. It also provided on-the-job training to many students, improving their future employment opportunities, while also providing valuable information to further advance FDWT's mixer-ejector wind turbine technology, creating opportunities for future project innovation and job creation.

  12. Virtual Tower

    International Nuclear Information System (INIS)

    Wayne, R.A.

    1997-01-01

    The primary responsibility of an intrusion detection system (IDS) operator is to monitor the system, assess alarms, and summon and coordinate the response team when a threat is acknowledged. The tools currently provided to the operator are somewhat limited: monitors must be switched, keystrokes must be entered to call up intrusion sensor data, and communication with the response force must be maintained. The Virtual tower is an operator interface assembled from low-cost commercial-off-the-shelf hardware and software; it enables large amounts of data to be displayed in a virtual manner that provides instant recognition for the operator and increases assessment accuracy in alarm annunciator and control systems. This is accomplished by correlating and fusing the data into a 360-degree visual representation that employs color, auxiliary attributes, video, and directional audio to prompt the operator. The Virtual Tower would be a valuable low-cost enhancement to existing systems

  13. Flicker Study on Variable Speed Wind Turbines with Permanent Magnet Synchronous Generator

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Wang, Yue

    2008-01-01

    capacity, grid impedance angle) are analyzed. Flicker mitigation is realized by output reactive power control of the variable speed wind turbines with PMSG. Simulation results show the output reactive power control is an effective measure to mitigate the flicker during continuous operation of grid......Grid connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbines with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed...... in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated during continuous operation. The dependence of flicker emission on wind characteristics (mean speed, turbulence intensity), 3p torque oscillations due to wind shear and tower shadow effects and grid conditions (short circuit...

  14. Mycobacteria in Finnish cooling tower waters.

    Science.gov (United States)

    Torvinen, Eila; Suomalainen, Sini; Paulin, Lars; Kusnetsov, Jaana

    2014-04-01

    Evaporative cooling towers are water systems used in, e.g., industry and telecommunication to remove excess heat by evaporation of water. Temperatures of cooling waters are usually optimal for mesophilic microbial growth and cooling towers may liberate massive amounts of bacterial aerosols. Outbreaks of legionellosis associated with cooling towers have been known since the 1980's, but occurrences of other potentially pathogenic bacteria in cooling waters are mostly unknown. We examined the occurrence of mycobacteria, which are common bacteria in different water systems and may cause pulmonary and other soft tissue infections, in cooling waters containing different numbers of legionellae. Mycobacteria were isolated from all twelve cooling systems and from 92% of the 24 samples studied. Their numbers in the positive samples varied from 10 to 7.3 × 10(4) cfu/L. The isolated species included M. chelonae/abscessus, M. fortuitum, M. mucogenicum, M. peregrinum, M. intracellulare, M. lentiflavum, M. avium/nebraskense/scrofulaceum and many non-pathogenic species. The numbers of mycobacteria correlated negatively with the numbers of legionellae and the concentration of copper. The results show that cooling towers are suitable environments for potentially pathogenic mycobacteria. Further transmission of mycobacteria from the towers to the environment needs examination. © 2013 APMIS. Published by John Wiley & Sons Ltd.

  15. Vibration-induced settlement of a slip-joint connection for offshore wind turbines

    NARCIS (Netherlands)

    Segeren, M.L.A.

    2018-01-01

    The majority of existing offshore wind turbines typically consist of a monopile foundation, a transition piece with a vertically positioned grouted connection, a turbine tower, and a turbine. Of the 2,653 offshore turbines that were installed by the end of 2015, 80 percent are supported by a

  16. Tribology of a Combined Yaw Bearing and Brake for Wind Turbines

    DEFF Research Database (Denmark)

    Poulios, Konstantinos

    disc brake is typically included as an independent system. However, the increasing size of wind turbines makes roller element bearings an economically costly option. Moreover, the additional brake system increases complexity and consequently adds further production and maintenance costs. One...... of the innovations aiming at reducing complexity in the yaw system consists in combining a segmented sliding bearing and a brake into a single system. This thesis studies the tribological implications of such a hybrid sliding bearing and brake for the yaw system of wind turbines. Based to a large extent...... that are affected by the tendency for building larger units, is the yaw system of horizontal axis wind turbines. State of the art wind turbine yaw systems consist of either a large roller element bearing or a corresponding segmented sliding bearing that connects the wind turbine nacelle and tower. An additional...

  17. The future of utility-scale wind power

    International Nuclear Information System (INIS)

    Hock, S.; Thresher, R.; Williams, T.

    1992-01-01

    The U.S. Department of Energy (DOE) estimates that by 2030, wind power could potentially displace between 3 and 4 quadrillion (10 15 ) Btus (quads) of primary energy, with an installed electrical generation capacity of 120,000 to 160,000 MW. This forecast is based upon economic analyses indicating that the costs of wind-generated electricity could be cost competitive with conventional fossil-fuel-based generation by early next century. The key to realizing this objective is overcoming technical challenges to the development of a next-generation of advanced wind turbines. These challenges include the detailed characterization of wind inflow to turbines at wind-power-plant sites, an understanding of unsteady aerodynamics, the development of sophisticated computer models of all aspects of turbine operation, and the application of a better understanding of component and system fatigue to new designs. Advanced wind systems will include such new technologies as blade designs incorporating advanced airfoils and new materials, variable-speed operation, advanced power electronics, rotor-hub enhancements, tall towers, aerodynamic controls, advanced drive trains, and expert control systems. A larger market share for wind energy will also require the resolution of issues surrounding transmission, storage, and the integration of an intermittent energy source into the utility grid

  18. Cellular Phone Towers, Tower locations and attributes generated from FCC anntenna registration database. Tower data was cross referenced with county zoning special use permits., Published in 2008, 1:600 (1in=50ft) scale, Waupaca County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Cellular Phone Towers dataset current as of 2008. Tower locations and attributes generated from FCC anntenna registration database. Tower data was cross referenced...

  19. Reports on 1979 result of Sunshine Project. Testing research for detailed design of solar thermal power generation plant (tower converging method); 1979 nendo taiyonetsu hatsuden plant (tower shuko hoshiki) no shosai sekkei no tame no shiken kenkyu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1980-03-31

    This report briefly describes first, in the summary of the results, the contents of the research results of the year with the outcome as the central point. Then, it explains in detail, in the contents of the research, the substance of each research item, results, their examination contents, and future research subjects. The objective of the research is, for the purpose of technically seeking the cost performance of a solar thermal power generation plant, (1) to develop equipment constituting the plant and (2) to develop a pilot plant having an electrical output of about 1,000kW at the peak by the tower converging method. The research results were as follows. (1) In the confirming test of a heliostat test unit, the final conclusion was obtained of the wind resistance calculated value by the wind tunnel test of the heliostat; the design materials of the assembly jigs were obtained; the data of the operation forecast was obtained in a tracking test; and a sensor was developed for the tracking instrumentation. (2) In the confirming test of the improved absorbing surface/mirror, the improvement/trial production including the manufacturing method was carried out as the absorbing surface for the actual unit. (3) In the heat collecting test, steam generation and a loop control test were performed. (4) The plant system was analyzed, with data obtained for the operating method. (NEDO)

  20. Improving the efficiency of natural draft cooling towers

    International Nuclear Information System (INIS)

    Smrekar, J.; Oman, J.; Sirok, B.

    2006-01-01

    This study shows how the efficiency of a natural draft cooling tower can be improved by optimising the heat transfer along the cooling tower (CT) packing using a suitable water distribution across the plane area of the cooling tower. On the basis of cooling air measurements, it is possible to distribute the water in such a way that it approaches the optimal local water/air mass flow ratio and ensures the homogeneity of the heat transfer and a reduction of entropy generation, thus minimising the amount of exergy lost. The velocity and temperature fields of the air flow were measured with the aid of a remote control mobile robot unit that was developed to enable measurements at an arbitrary point above the spray zone over the entire plane area of the cooling tower. The topological structures of the moist air velocity profiles and the temperature profiles above the spray zone were used as input data for calculation of the local entropy generation in the tower. On the basis of the measured boundary conditions, a numerical analysis of the influence of the water distribution across the cooling tower's plane area on entropy generation and exergy destruction in the cooling tower was conducted

  1. Improving the efficiency of natural draft cooling towers

    Energy Technology Data Exchange (ETDEWEB)

    Smrekar, J. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia); Oman, J. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia)]. E-mail: janez.oman@fs.uni-lj.si; Sirok, B. [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia)

    2006-06-15

    This study shows how the efficiency of a natural draft cooling tower can be improved by optimising the heat transfer along the cooling tower (CT) packing using a suitable water distribution across the plane area of the cooling tower. On the basis of cooling air measurements, it is possible to distribute the water in such a way that it approaches the optimal local water/air mass flow ratio and ensures the homogeneity of the heat transfer and a reduction of entropy generation, thus minimising the amount of exergy lost. The velocity and temperature fields of the air flow were measured with the aid of a remote control mobile robot unit that was developed to enable measurements at an arbitrary point above the spray zone over the entire plane area of the cooling tower. The topological structures of the moist air velocity profiles and the temperature profiles above the spray zone were used as input data for calculation of the local entropy generation in the tower. On the basis of the measured boundary conditions, a numerical analysis of the influence of the water distribution across the cooling tower's plane area on entropy generation and exergy destruction in the cooling tower was conducted.

  2. Adiabatic Rearrangement of Hollow PV Towers

    Directory of Open Access Journals (Sweden)

    Eric A Hendricks

    2010-10-01

    Full Text Available Diabatic heating from deep moist convection in the hurricane eyewall produces a towering annular structure of elevated potential vorticity (PV. This structure has been referred to as a hollow PV tower. The sign reversal of the radial gradient of PV satisfies the Charney-Stern necessary condition for combined barotropic-baroclinic instability. For thin enough annular structures, small perturbations grow exponentially, extract energy from the mean flow, and lead to hollow tower breakdown, with significant vortex structural and intensity change. The three-dimensional adiabatic rearrangements of two prototypical hurricane-like hollow PV towers (one thick and one thin are examined in an idealized framework. For both hollow towers, dynamic instability causes air parcels with high PV to be mixed into the eye preferentially at lower levels, where unstable PV wave growth rates are the largest. Little or no mixing is found to occur at upper levels. The mixing at lower and middle levels is most rapid for the breakdown of the thin hollow tower, consistent with previous barotropic results. For both hollow towers, this advective rearrangement of PV affects the tropical cyclone structure and intensity in a number of ways. First, the minimum central pressure and maximum azimuthal mean velocity simultaneously decrease, consistent with previous barotropic results. Secondly, isosurfaces of absolute angular momentum preferentially shift inward at low levels, implying an adiabatic mechanism by which hurricane eyewall tilt can form. Thirdly, a PV bridge, similar to that previously found in full-physics hurricane simulations, develops as a result of mixing at the isentropic levels where unstable PV waves grow most rapidly. Finally, the balanced mass field resulting from the PV rearrangement is warmer in the eye between 900 and 700 hPa. The location of this warming is consistent with observed warm anomalies in the eye, indicating that in certain instances the hurricane

  3. Wind Energy Potential and Power Law Indexes Assessment for Selected Near-Coastal Sites in Malaysia

    Directory of Open Access Journals (Sweden)

    Aliashim Albani

    2017-03-01

    Full Text Available This paper investigated the wind energy potential by analysing a certain amount of gathered 10-min measured data at four stations located at coastal sites in Malaysia, i.e., Kudat, Mersing, Kijal, and Langkawi. The wind data are collected from a total of four new wind measurement masts with sensors mounted at various heights on the tower. The measured data have enabled the establishment of wind resource maps and the power law indexes (PLIs analysis. In addition, the dependence of PLI upon surface temperature and terrain types is studied, as they are associated to the form of exponential fits. Moreover, the accuracy of exponential fits is assessed by comparing the results with the 1/7 law via the capacity factor (CF discrepancies. In order to do so, the wind turbine with a hub-height similar to the maximum height of the measured data at each site is selected to simulate energy production. Accordingly, the discrepancy of CF based on the extrapolated data by employing 1/7 laws and exponential fits, in spite of being computed using measured data, is determined as well. Furthermore, the large discrepancy of the wind data and the CF, which has been determined with the application of 1/7, is compared to the exponential fits. This is because; discrepancy in estimation of vertical wind speed could lead to inaccurate CF computation. Meanwhile, from the energy potential analysis based on the computed CF, only Kudat and Mersing display a promising potential to develop a medium capacity of wind turbine power, while the other sites may be suitable for wind turbines at a small scale.

  4. Comparison of Second-Order Loads on a Tension-Leg Platform for Wind Turbines: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Gueydon, S.; Wuillaume, P.; Jonkman, J.; Robertson, A.; Platt, A.

    2015-03-01

    The first objective of this work is to compare the two floating offshore wind turbine simulation packages {DIFFRAC+aNySIM} and {WAMIT+FAST}. The focus is on second-order wave loads, and so first- and second-order wave loads are applied to a structure sequentially for a detailed comparison and a more precise analysis of the effects of the second-order loads. aNySIM does not have the capability to model flexible bodies, and so the simulations performed in this tool are done assuming a rigid body. FAST also assumes that the platform is rigid, but can account for the flexibility of the tower. The second objective is to study the effects of the second-order loads on the response of a TLP floating wind turbine. The flexibility of the tower must be considered for this investigation, and therefore only FAST is used.

  5. RSA/Legacy Wind Sensor Comparison. Part 2; Eastern Range

    Science.gov (United States)

    Short, David A.; Wheeler, Mark M.

    2006-01-01

    This report describes a comparison of data from ultrasonic and propeller-and-vane anemometers on 5 wind towers at Kennedy Space Center and Cape Canaveral Air Force Station. The ultrasonic sensors are scheduled to replace the Legacy propeller-and-vane sensors under the Range Standardization and Automation (RSA) program. Because previous studies have noted differences between peak wind speeds reported by mechanical and ultrasonic wind sensors, the latter having no moving parts, the 30th and 45th Weather Squadrons wanted to understand possible differences between the two sensor types. The period-of-record was 13-30 May 2005, A total of 357,626 readings of 1-minute average and peak wind speed/direction from each sensor type were used. Statistics of differences in speed and direction were used to identify 15 out of 19 RSA sensors having the most consistent performance, with respect to the Legacy sensors. RSA average wind speed data from these 15 showed a small positive bias of 0.38 kts. A slightly larger positive bias of 0.94 kts was found in the RSA peak wind speed.

  6. Ejection Tower Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The Ejection Tower Facility's mission is to test and evaluate new ejection seat technology being researched and developed for future defense forces. The captive and...

  7. Modeling of Direct Contact Wet Cooling Tower in ETRR-2

    International Nuclear Information System (INIS)

    El Khatib, H.H.; Ismail, A.L.; ElRefaie, M.E.

    2008-01-01

    The Egyptian Testing and Research Reactor no.2 (ETRR-2) was commissioned at 1997 with maximum power 22 MW for research purposes; an induced draft wet cooling tower (counter flow type) was putted in operation in 2003 instead of the first one. Investigations are achieved to evaluate cooling tower performance to guarantee that the cooling tower capable to dissipate heat generated in reactor core. Merkel and Poppe analysis was applied to simulate this cooling tower packing. Merkel analysis was applied to predict water outlet temperature from cooling tower and also to show the effect of ambient conditions on this temperature. Poppe analysis was applied to predict Merkel number which evaluate cooling tower. The Runge-Kutta numerical method was applied to solve the differential equations in this model and an engineering equation solver (EES) is the language used to model the cooling tower. This research illustrates that the cooling tower achieves good performance in various sever ambient condition at maximum operating condition of reactor power. The results show that at severe summer condition of wet bulb temperature equals 24 degree c and tower inlet temperature equals 37 degree c, the outlet water temperature equals 30.4 degree c from cooling tower, while the Merkel number is be found 1.253

  8. The shape of natural draft cooling towers

    International Nuclear Information System (INIS)

    Grange, J.L.

    1992-07-01

    The shape of cooling towers is more often designed empirically. There, it is considered from a theoretical point of view. The analysis of dynamic of natural draft and of the air flow in a cooling tower shell is presented. It is shown, that although it is convergent, a tower works like a diffuser for pressure recovery. And it is turbulence that produces a transfer of kinetic energy and allows a good operation of the diffusor. The equations permit to define a shell profile which depends upon the operating conditions of the cooling tower. In the same way, a stability criteria for natural draft depending upon operating conditions is established. A heating model of one meter diameter has been built in a thermal similitude. The turbulence rate has been measured with a hot wire anemometer at the tower exit and visualizations have also been made. Natural draft stability has been studied by these means for four different shell shapes and a wide range of operating conditions. Experimental and theoretical results agree satisfactorily and experiments can be considered as a validation of theory

  9. Engineering photochemical smog through convection towers

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, S.; Prueitt, M.L.; Bossert, J.E.; Mroz, E.J.; Krakowski, R.A.; Miller, R.L. [Los Alamos National Lab., NM (United States); Jacobson, M.Z.; Turco, R.P. [Los Alamos National Lab., NM (United States)]|[Univ. of California, Los Angeles, CA (United States). Atmospheric Sciences Dept.

    1995-02-01

    Reverse convection towers have attracted attention as a medium for cleansing modern cities. Evaporation of an aqueous mist injected at the tower opening could generate electrical power by creating descent, and simultaneously scavenge unsightly and unhealthful particulates. The study offered here assesses the influence to tower water droplets on the photochemical component of Los Angeles type smog. The primary radical chain initiator OH is likely removed into aqueous phases well within the residence time of air in the tower, and then reacts away rapidly. Organics do not dissolve, but nighttime hydrolysis of N{sub 2}O{sub 5} depletes the nitrogen oxides. A lack of HOx would slow hydrocarbon oxidation and so also ozone production. Lowering of NOx would also alter ozone production rates, but the direction is uncertain. SO{sub 2} is available in sufficient quantities in some urban areas to react with stable oxidants, and if seawater were the source of the mist, the high pH would lead to fast sulfur oxidation kinetics. With an accommodation coefficient of 10{sup {minus}3}, however, ozone may not enter the aqueous phase efficiently. Even if ozone is destroyed or its production suppressed, photochemical recovery times are on the order of hours, so that tower processing must be centered on a narrow midday time window. The cost of building the number of structures necessary for this brief turnover could be prohibitive. The increase in humidity accompanying mist evaporation could be controlled with condensers, but might otherwise counteract visibility enhancements by recreating aqueous aerosols. Quantification of the divergent forcings convection towers must exert upon the cityscape would call for coupled three dimensional modeling of transport, microphysics, and photochemistry. 112 refs.

  10. Occupational exposure to radiofrequency fields in antenna towers

    International Nuclear Information System (INIS)

    Alanko, T.; Hietanen, M.

    2007-01-01

    Exposure of workers to radiofrequency fields was assessed in two medium-sized antenna towers. Towers had transmitting antennas from different networks, e.g. mobile phone networks, radio and digital TV sub-stations and amateur radio. The levels of radiofrequency fields were measured close to the ladders of the towers. All measured values were below ICNIRP occupational reference levels. (authors)

  11. Cooling tower water ozonation at Southern University

    International Nuclear Information System (INIS)

    Chen, C.C.; Knecht, A.T.; Trahan, D.B.; Yaghi, H.M.; Jackson, G.H.; Coppenger, G.D.

    1990-01-01

    Cooling-tower water is a critical utility for many industries. In the past, inexpensive water coupled with moderate regulation of discharge water led to the neglect of the cooling tower as an energy resource. Now, with the increased cost of chemical treatment and tough EPA rules and regulations, this situation is rapidly changing. The operator of the DOE Y-12 Plant in Oak Ridge as well as many other industries are forced to develop an alternate method of water treatment. The cooling tower is one of the major elements in large energy systems. The savings accrued from a well engineered cooling tower can be a significant part of the overall energy conservation plan. During a short-term ozonation study between 1987-1988, the Y-12 Plant has been successful in eliminating the need for cooling tower treatment chemicals. However, the long-term impact was not available. Since April 1988, the ozone cooling water treatment study at the Y-12 Plant has been moved to the site at Southern University in Baton Rouge, Louisiana. The purpose of this continued study is to determine whether the use of ozonation on cooling towers is practical from an economic, technical and environmental standpoint. This paper discusses system design, operating parameter and performance testing of the ozonation system at Southern University

  12. Long-Term Profiles of Wind and Weibull Distribution Parameters up to 600 m in a Rural Coastal and an Inland Suburban Area

    DEFF Research Database (Denmark)

    Gryning, Sven-Erik; Batchvarova, Ekaterina; Floors, Rogier Ralph

    2014-01-01

    An investigation of the long-term variability of wind profiles for wind energy applications is presented. The observations consists of wind measurements obtained from a ground-based wind lidar at heights between 100 and 600 m, in combination with measurements from tallmeteorological towers...... by the root-mean-square error was about 10 % lower for the analysis compared to the forecast simulations. At the rural coastal site, the observed mean wind speeds above 60 m were underestimated by both the analysis and forecast model runs. For the inland suburban area, the mean wind speed is overestimated...

  13. The new Drop Tower catapult system

    Science.gov (United States)

    von Kampen, Peter; Kaczmarczik, Ulrich; Rath, Hans J.

    2006-07-01

    The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of the "Drop Tower" began. Since then, the eye-catching tower with a height of 146 m and its characteristic glass roof has become the emblem of the technology centre in Bremen. The Drop Tower Bremen provides a facility for experiments under conditions of weightlessness. Items are considered weightless, when they are in "free fall", i.e. moving without propulsion within the gravity field of the earth. The height of the tower limits the simple "free fall" experiment period to max. 4.74 s. With the inauguration of the catapult system in December 2004, the ZARM is entering a new dimension. This world novelty will meet scientists' demands of extending the experiment period up to 9.5 s. Since turning the first sod on May 3rd, 1988, the later installation of the catapult system has been taken into account by building the necessary chamber under the tower. The catapult system is located in a chamber 10 m below the base of the tower. This chamber is almost completely occupied by 12 huge pressure tanks. These tanks are placed around the elongation of the vacuum chamber of the drop tube. In its centre there is the pneumatic piston that accelerates the drop capsule by the pressure difference between the vacuum inside the drop tube and the pressure inside the tanks. The acceleration level is adjusted by means of a servo hydraulic breaking system controlling the piston velocity. After only a quarter of a second the drop capsule achieves its lift-off speed of 175 km/h. With this exact speed, the capsule will rise up to the top of the tower and afterwards fall down again into the deceleration unit which has been moved under the drop tube in the meantime. The scientific advantages of the doubled experiment time are obvious: during almost 10 s of high

  14. Wind energy conversion. Volume II. Aerodynamics of horizontal axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.H.; Dugundji, J.; Martinez-Sanchez, M.; Gohard, J.; Chung, S.; Humes, T.

    1978-09-01

    The basic aerodynamic theory of the wind turbine is presented, starting with the simple momentum theory based on uniform inflow and an infinite number of blades. The basic vortex theory is then developed. Following these basics, the more complete momentum theory, including swirl, non-uniform inflow, the effect of a finite number of blades, and empirical correction for the vortex ring condition is presented. The more complete vortex theory is presented which includes unsteady aerodynamic effects but based on a semi-rigid wake. Methods of applying this theory for performance estimation are discussed as well as for the purpose of computing time varying airloads due to windshear and tower interference.

  15. RELIABILITY OF MACHINE ELEMENTS IN WIND TURBINES

    Directory of Open Access Journals (Sweden)

    Willi GRUENDER

    2010-06-01

    Full Text Available Worldwide electrical energy production generated by wind turbines grows at a rate of 30 percent. This doubles the total production every three years. At the same time the power of individual stations goes up by 20 percent annually. Whereas today the towers, rotors and drive trains have to handle 5 MW, in about six to eight years they might produce up to fifteen MW. As a consequence, enormous pressure is put on the wind turbine manufacturers, the component suppliers and the operators. And because prototype and field testing is limited by its expense, the design of new turbines demands thorough analysis and simulation. Looking at the critical components of a wind turbine this paper describes advanced design tools which help to anticipate failures, but also assists in optimizing reliability and service life. Development of the software tools has been supported by research activities in many universities.

  16. Sensitivity of Nodal Admittances in an Offshore Wind Power Plant to Parametric Variations in the Collection Grid

    DEFF Research Database (Denmark)

    Vytautas, Kersiulis; Holdyk, Andrzej; Holbøll, Joachim

    2012-01-01

    The paper presents sensitivity studies on nodal admittances in the offshore wind farm to different parameters of the collection grid cable system, including length of cable sections and actual layout configuration. The main aspect of this investigation is to see how parametric variations influence...... admittance and, consequently, voltage transfer in frequency domain. The simulation model of the offshore wind farm was build based on the main components in turbines and the collection grid. The simulation results were compared with data from time domain measurements and showed good agreement. A number...... of nodes were selected for evaluation of the admittances: the connection point to the external grid, a point at the substation and at each wind turbine. The results show that at specific locations resonances occur, where the admittance increases significantly in the 10-100 kHz range, depending...

  17. Mobile Tower Radiation Protection System

    Directory of Open Access Journals (Sweden)

    Jabbar Slman Hussein

    2017-12-01

    Full Text Available Clean environment is one of the most necessarily needs for Human life. So what about mobile effect and its towers pollution? It's effect on public health? Effect of huge groan of mobile networks. In counting of these dangers that will harm us from mobile towers in the far run, was the reasons for writing this research, came this study to look at the mobile towers and mobile effects possible health harm for the purpose of diagnosis of these effects and to suggest ways that can be used to avoid or minimize the risks.  Faraday Cage, is the solution suggested here, also there are many other solutions for this problem, a Faraday cage is a metallic enclosure that stops the entry or escape of an EM field. Also, two experiments are accomplished, first one showing the effect of Faraday cage on preventing the EMR from mobile cellphone, and the second  experiment gives the effect of Faraday cage on preventing the EMR from mobile tower EMR on human health listed in the research, that have been done by using conducting shell (grid design according the EM wavelength used by three company's mobile working in Iraq, the result show good isolations.

  18. Model predictive control of trailing edge flaps on a wind turbine blade

    DEFF Research Database (Denmark)

    Castaignet, Damien Bruno

    of the wind turbine fatigue and extreme loads. This potential was confirmed with wind tunnel tests made on blade sections with trailing edge flaps and on a scaled two-bladed wind turbine in a wind tunnel. The work presented in this thesis includes a full-scale test run on a Vestas V27 wind turbine equipped...... fatigue loads by 23%, but also the main shaft and the tower fatigue loads by up to 32%. Extreme loads during normal production also benefit from the trailing edge flaps. At last, the same controller was run on the Vestas V27 wind turbine located at the Risø Campus of the Technical University of Denmark......Trailing edge flaps on wind turbine blades have been investigated for several years. Aero-servoelastic simulations carried out with different simulation tools, trailing edge flaps configurations and controller designs proved that trailing edge flaps are a suitable solution for reducing some...

  19. Cooling towers

    International Nuclear Information System (INIS)

    Boernke, F.

    1975-01-01

    The need for the use of cooling systems in power plant engineering is dealt with from the point of view of a non-polluting form of energy production. The various cooling system concepts up to the modern natural-draught cooling towers are illustrated by examples. (TK/AK) [de

  20. Understanding the Benefits and Limitations of Increasing Maximum Rotor Tip Speed for Utility-Scale Wind Turbines

    International Nuclear Information System (INIS)

    Ning, A; Dykes, K

    2014-01-01

    For utility-scale wind turbines, the maximum rotor rotation speed is generally constrained by noise considerations. Innovations in acoustics and/or siting in remote locations may enable future wind turbine designs to operate with higher tip speeds. Wind turbines designed to take advantage of higher tip speeds are expected to be able to capture more energy and utilize lighter drivetrains because of their decreased maximum torque loads. However, the magnitude of the potential cost savings is unclear, and the potential trade-offs with rotor and tower sizing are not well understood. A multidisciplinary, system-level framework was developed to facilitate wind turbine and wind plant analysis and optimization. The rotors, nacelles, and towers of wind turbines are optimized for minimum cost of energy subject to a large number of structural, manufacturing, and transportation constraints. These optimization studies suggest that allowing for higher maximum tip speeds could result in a decrease in the cost of energy of up to 5% for land-based sites and 2% for offshore sites when using current technology. Almost all of the cost savings are attributed to the decrease in gearbox mass as a consequence of the reduced maximum rotor torque. Although there is some increased energy capture, it is very minimal (less than 0.5%). Extreme increases in tip speed are unnecessary; benefits for maximum tip speeds greater than 100-110 m/s are small to nonexistent