scholarly journals Monitoring and Modeling Roof-Level Wind Speed in a Changing City

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 87
Author(s):  
Kathrin Baumann-Stanzer ◽  
Sirma Stenzel ◽  
Gabriele Rau ◽  
Martin Piringer ◽  
Felix Feichtinger ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Urban Areas ◽  
Dispersion Model ◽  
Flow Direction ◽  
Energy Yield ◽  
Wind Speeds ◽  
Small Wind Turbine ◽  
Roof Level

Results of an observational campaign and model study are presented demonstrating how the wind field at roof-level in the urban area of Vienna changed due to the construction of a new building nearby. The investigation was designed with a focus on the wind energy yield of a roof-mounted small wind turbine but the findings are also relevant for air dispersion applications. Wind speed profiles above roof top are simulated with the complex fluid dynamics (CFD) model MISKAM (Mikroskaliges Klima- und Ausbreitungsmodell, microscale climate and dispersion model). The comparison to mast measurements reveals that the model underestimates the wind speeds within the first few meters above the roof, but successfully reproduces wind conditions at 10 m above the roof top (corresponding to about 0.5 times the building height). Scenario simulations with different building configurations at the adjacent property result in an increase or decrease of wind speed above roof top depending on the flow direction at the upper boundary of the urban canopy layer (UCL). The maximum increase or decrease in wind speed caused by the alternations in building structure nearby is found to be in the order of 10%. For the energy yield of a roof-mounted small wind turbine at this site, wind speed changes of this magnitude are negligible due to the generally low prevailing wind speeds of about 3.5 m s−1. Nevertheless, wind speed changes of this order could be significant for wind energy yield in urban areas with higher mean wind speeds. This effect in any case needs to be considered in siting and conducting an urban meteorological monitoring network in order to ensure the homogeneity of observed time-series and may alter the emission and dispersion of pollutants or odor at roof level.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

scholarly journals Numerical Simulation of the Aeroelastic Response of Wind Turbines in Typhoons Based on the Mesoscale WRF Model

2019 ◽  
Vol 12 (1) ◽  
pp. 34
Author(s):  
Long Wang ◽  
Cheng Chen ◽  
Tongguang Wang ◽  
Weibin Wang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Direction ◽  
Flow Direction ◽  
Wrf Model ◽  
Normal Operation ◽  
Average Wind Speed ◽  
Aeroelastic Response ◽  
Response Characteristics ◽  
Wind Speeds

A new simulation method for the aeroelastic response of wind turbines under typhoons is proposed. The mesoscale Weather Research and Forecasting (WRF) model was used to simulate a typhoon’s average wind speed field. The measured power spectrum and inverse Fourier transform method were coupled to simulate the pulsating wind speed field. Based on the modal method and beam theory, the wind turbine model was constructed, and the GH-BLADED commercial software package was used to calculate the aerodynamic load and aeroelastic response. The proposed method was applied to assess aeroelastic response characteristics of a commercial 6 MW offshore wind turbine under different wind speeds and direction variation patterns for the case study of typhoon Hagupit (2008), with a maximal wind speed of 230 km/h. The simulation results show that the typhoon’s average wind speed field and turbulence characteristics simulated by the proposed method are in good agreement with the measured values: Their difference in the main flow direction is only 1.7%. The scope of the wind turbine blade in the typhoon is significantly larger than under normal wind, while that under normal operation is higher than that under shutdown, even at low wind speeds. In addition, an abrupt change in wind direction has a significant impact on wind turbine response characteristics. Under normal operation, a sharp variation of the wind direction by 90 degrees in 6 s increases the wind turbine (WT) vibration scope by 27.9% in comparison with the case of permanent wind direction. In particular, the maximum deflection of the wind tower tip in the incoming flow direction reaches 28.4 m, which significantly exceeds the design standard safety threshold.

scholarly journals The Potential Wind Power Resource in Central-South of the Constanta County

2019 ◽  
Vol 15 (3) ◽  
pp. 1-12
Author(s):  
Emilian Boboc
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Extreme Values ◽  
Reanalysis Data ◽  
Value Theory ◽  
Physical Models ◽  
Structural Safety ◽  
Energy Yield ◽  
Wind Speeds ◽  
Mean Wind Speed

Abstract Usually, wind turbine generator’s structures or radio masts are located in wind exposed sites. The paper aims to investigate the wind conditions in the nearby area of Cobadin Commune, Constanta County, Romania at heights of 150-200m above the surface using global reanalysis data sets CFSR, ERA 5, ERA I and MERRA 2. Using the extreme value theory and the physical models of the datasets, the research focuses on the assessment of the maximum values that are expected for the wind speeds, but the wind statistics created can be used for a further wind or energy yield calculation. Without reaching the survival wind speed for wind turbine generators, with mean wind speed values higher than 7 m/s and considering the cut-in and cut-out wind speeds of 3 m/s, respectively 25 m/s, the site can be exploited in more than 90% of the time to generate electricity, thus, the paper is addressed to the investors in the energy of renewable sources. At the same time, the insights of the wind characteristics and the knowledge of the extreme values of the wind speed can be useful, not just for the designers, in the rational assessment of the structural safety of wind turbines, but also those evaluating the insured losses.

Comparison of Various Blade Profiles in a Two-Blade Conventional Savonius Wind Turbine

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Rahim Hassanzadeh ◽  
Milad Mohammadnejad ◽  
Sajad Mostafavi
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Power Output ◽  
Urban Areas ◽  
Cost Effective ◽  
Maximum Power ◽  
Power Coefficient ◽  
Total Power ◽  
Wind Speeds ◽  
Savonius Wind Turbine

Abstract Savonius turbines are one of the old and cost-effective turbines which extract the wind energy by the drag force. Nowadays, they use in urban areas to generate electricity due to their simple structure, ease of maintenance, and acceptable power output under a low wind speed. However, their efficiency is low and the improvement of their performance is necessary to increase the total power output. This paper compares four various blade profiles in a two-blade conventional Savonius wind turbine. The ratios of blade diameter to the blade depth of s/d = 0.3, 0.5, 0.7, and 1 are tested under different free-wind speeds of 3, 5, and 7 m/s and tip speed ratios (TSRs) in the range from 0.2 to 1.2. It is found that the profile of blades in a Savonius rotor plays a considerable role in power characteristics. Also, regardless of blades profile and free-wind speed, the maximum power coefficient develops in TSR = 0.8. In addition, increasing the free-wind speed enhances the rotor performance of all cases under consideration. Finally, it is revealed that the rotor with s/d = 0.5 provides maximum power coefficients in all free-wind speeds and TSR values among the rotors under consideration, whereas the rotor with s/d = 1 is the worth cases.

Performance Evaluation of a Novel Small Wind Turbine: UAE Case Study

2016 ◽  
Author(s):  
Sayem Zafar ◽  
Mohamed Gadalla ◽  
Mohammad Ismail Al-Naiser
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
United Arab Emirates ◽  
Electrical Power ◽  
Electrical Efficiency ◽  
Wind Speeds ◽  
Small Wind Turbine ◽  
Sufficient Power ◽  
Personal Use ◽  
Domestic Power

A small personal use wind turbine (PWT) is studied and tested for power evaluation under different wind speed conditions. The wind turbine has small blades with FX 63137 airfoil. The blades are non-tapered and non-twisted to be economical and easy to manufacture. The blade span is 1.52 m which makes it small enough for personal domestic use yet big enough to produce sufficient power. The PWT size satisfies the requirements for rooftop small wind turbine for domestic power generation. The study is conducted in United Arab Emirates (UAE) and the PWT is installed in an open area to test under the natural conditions. Readings are recorded for wind speeds, generator RPMs, current and voltage for different timings and conditions. The PWT is tested at a variety of wind speeds to establish the operating range of the wind turbine. Using the calculated electrical power and wind power values, corresponding electrical efficiency is determined. Results are evaluated for electrical power and electrical efficiency against wind speed. The result suggests better performance and efficiency for continuous wind speed conditions. It also shows the PWT can effectively generate power under the conditions found in UAE.

Wind Energy Harnessing System for Low and High Wind Speeds

2019 ◽  
Author(s):  
Majid Rashidi ◽  
Jaikrishnan R. Kadambi ◽  
Renjie Ke
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
High Speed ◽  
Power Transmission ◽  
Vertical Axis ◽  
Geographic Locations ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Energy Harnessing

Abstract This work presents the design and analysis of a novel wind energy harnessing system that makes use of wind defecting structures to increase the ambient wind speed at geographic locations with relatively low wind speed. The system however reacts to highspeed wind conditions by altering the profile of the wind defecting structure in order to eliminate wind speed amplification attribute of the system, thereby protecting the wind turbine assembly at high speed wind conditions. Although increasing the wind speed is advantageous at geographic locations that the wind speed is typically low; however, from times to time, there could be sustained high-speed wind conditions at the same locations that may damage the wind turbine systems that take advantage of the wind defecting structures. The present work disclosed a wind deflecting structure formed by at least two sail-like partial cylindrical structures that are supported atop of a tower-like foundation in a symmetric arrangement, where one or more wind turbines can be installed in the space between the two partial cylinders. The two partial cylinders, each substantially in form a quarter cylinder is made of plurality of parallel ribbed-like bars, hereafter referred to as “bars” with a flexible thin material that are mechanically supported by the bars. The bars are oriented in a direction perpendicular to the ground; allowing the wing deflecting structures to accept horizonal axis or vertical axis turbines in the space between them. The function of the bars is to allow the thin material, attached to them, to assume a curved configuration substantially in the form of a quarter cylinder. The apparatus is equipped with wind speed monitoring devices, and power source and power transmission means, such as cable-pulleys, chain-sprockets, gears, or mechanical linkages that all work in concert to deploy or stow the thin material along the vertical rods depending to the magnitude of the prevailing wind speed. Preliminary computational fluid dynamics analyses have shown that the wind deflecting structure proposed here in amplifies the wind speed by a factor of 1.65.

Thermodynamic Evaluation of a Small Wind Turbine

2014 ◽  
Author(s):  
Mohamed Gadalla ◽  
Sayem Zafar ◽  
Saad Ahmed
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Operating Conditions ◽  
Thermodynamic Evaluation ◽  
Ambient Conditions ◽  
Wind Speeds ◽  
Small Wind Turbine ◽  
Wide Range ◽  
Mechanical Power Output ◽  
Energy And Exergy

A small personal use wind turbine (PWT) is studied and tested for power, exergy and energy evaluation under different operating conditions. The wind turbine incorporates non-twisted blades of 1.5 m span and 0.27 m chord, using NACA 63418 airfoil. Using the earlier test results at pitch angles of 22°, 34° and 38° between the wind speeds of 4 m/s to 7 m/s, torque produced by each blade is determined. It is desired to calculate the torque as it is difficult to measure it for a small wind turbine. Using the governing equations and available computational fluid dynamics software, the total torque on each blade is determined. The resultant torque yielded the mechanical power output of the PWT. Using the available power, energy and exergy in the air flow, corresponding efficiencies are determined. To determine the changes in energy and exergy with respect to the wind speed, wind-chill factor expression is utilized. Results are collected for a wide range of wind speeds and pitch angles. Power, energy, exergy and their corresponding efficiency is evaluated to determine the optimal use pitch angle and ambient conditions. The pitch angles of 22° and 38o yielded high efficiencies although 22° produced the higher rotational speed as compared to 38°. The result suggests better performance for continuous wind speed conditions at low pitch angles — with respect to the rotating plane. For non-continuous wind conditions, higher pitch angles appeared beneficial.

Adaptive Gain Modified Optimal Torque Controller for Wind Turbine Partial Load Operation

2014 ◽  
Author(s):  
Zheren Ma ◽  
Mohamed L. Shaltout ◽  
Dongmei Chen
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Gain Scheduling ◽  
Light Detection And Ranging ◽  
Operating Point ◽  
Energy Yield ◽  
Optimal Operating ◽  
Partial Load ◽  
The Impact

In this paper, an adaptive gain modified optimal torque controller (AGMOTC) is proposed and evaluated for wind turbine partial load operation. An internal PI technique is applied for gain scheduling in order to accelerate the controller response under volatile wind speed while the adaptive searching technique endows the controller with robust convergence to the optimal operating point under plant uncertainties. The light detection and ranging (LIDAR) technology is integrated with the AGMOTC to provide reliable previewed wind speed measurements. Simulations on the NREL 5MW wind turbine show that the LIDAR-enabled AGMOTC outperforms the baseline controller considering the wind energy yield. Additionally, the results show the impact of the proposed controller on the wind turbine fatigue loads.

scholarly journals Turbin angin poros vertikal tipe Savonius bertingkat dengan variasi posisi sudut

2016 ◽  
Vol 6 (2) ◽  
Author(s):  
I.B. Alit ◽  
Nurchayati Nurchayati ◽  
S.H. Pamuji
Keyword(s):  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Electric Power ◽  
Rotor Blade ◽  
Rotation Speed ◽  
Simple Construction ◽  
Wind Speeds ◽  
Turbine Performance ◽  
Low Wind Speeds

Wind turbine is a technology that converts wind energy to electric power. A Savonius type rotor blade is a simple wind turbine that operates on the concept of drag. The turbine has a potential to be developed as it has a simple construction and it is suitable for low wind speeds. Savonius rotor can be designed with two or three blades in single level or multi-levels. This research was conducted to obtain two levels wind turbine performance characteristics with variations in wind speed and different positions of angle on each level. The variations of the angle position of the wind turbine were 0°, 30°, 45°, 60°, and 90° in each stage. The result shows that the performance of the wind turbine is inversely to the degree of the angle position. The maximum rotation speed of the rotor was about 150.6 rpm that was generated at the wind speed of 5 m/s and the angle position of 0°. 

Optimization of the Wind Turbine Designs for Areas With Low Wind Speeds

2015 ◽  
Author(s):  
Mohammed S. Mayeed ◽  
Adeel Khalid
Keyword(s):  
Energy Consumption ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Small Scale ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Average Wind ◽  
The World

Wind energy has been identified as an important source of renewable energy. In this study, several wind turbine designs have been analyzed and optimized designs have been proposed for low wind speed areas around the world mainly for domestic energy consumption. The wind speed range of 4–12 mph is considered, which is selected based on the average wind speeds in the Atlanta, GA and surrounding areas. These areas have relatively low average wind speeds compared to various other parts of the United States. Traditionally wind energy utilization is limited to areas with higher wind speeds. In reality a lot of areas in the world have low average wind speeds and demand high energy consumption. In most cases, wind turbines are installed in remote offshore or away from habitat high wind locations, causing heavy investment in installation and maintenance, and loss of energy transfer over long distance. A few more advantages of small scale wind turbines include reduced visibility, less noise and reduced detrimental environmental effects such as killing of birds, when compared to traditional large turbines. With the latest development in wind turbine technology it is now possible to employ small scale wind turbines that have much smaller foot print and can generate enough energy for small businesses or residential applications. The low speed wind turbines are typically located near residential areas, and are much smaller in sizes compared to the large out of habitat wind turbines. In this study, several designs of vertical and horizontal axes wind turbines are modeled using SolidWorks e.g. no-airfoil theme, airfoil blade, Savonius rotor etc. Virtual aerodynamic analysis is performed using SolidWorks Flow simulation software, and then optimization of the designs is performed based on maximizing the starting rotational torque and ultimate power generation capacity. From flow simulations, forces on the wind turbine blades and structures are calculated, and used in subsequent stress analysis to confirm structural integrity. Critical insight into low wind speed turbines is obtained using various configurations, and optimized designs have been proposed. The study will help in the practical and effective utilization of wind energy for the areas around the globe having low average wind speeds.

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