Wind Energy DIY Guide

Home Wind Turbines

Build home wind turbines or residential wind turbines. Learn how residential wind power works. These instructions to build a windmill include a 1,000 watt and a 3,000 watt versions. This e-book is full of pictures and diagrams to explain the concepts: testing with 4 blades. testing with 6 blades. how to make Free homemade wind turbine blades and it will only take about an hour to finish a set of 3. a page full of equations and examples of how to use them to figure out power, rpm, tsr, windspeed etc. (units are in miles per hour and feet) how to find Free fork lift batteries and how to make them as good as new. making a homemade de-sulfator so you can pulse any battery back into new condition. what kind of generator to look for and how to get the best prices. how to make a simple curling system to protect the windmill in high winds. how to charge several banks of batteries all at once while pulsing them back to health. How to make a 1,000 watt wind turbine for less than $150 (including tower) How to make a 3,000 watt wind turbine for about $220! Continue reading...

Home Wind Turbines Summary

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Author: Richard Lewis
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Wind Energy Siting and Maintenance Costs

Wind energy projects may be on land or offshore, and can vary in scale from small projects of one to a few turbines to large, multi-turbine projects (denoted as utility-scale or wind farms). Utility-scale projects can consist of up to hundreds of wind turbines. These turbines are normally operated by independent power producers who sell the generated power to the local utility provider 12 . Wind turbine operation and maintenance (O and M) costs, which are known to be the predominant costs that contribute to the cost of wind energy, are generally attributed to a limited number of components, including insurance, land usage, maintenance, repair, spare parts, and administration 8, 13 . For most wind turbines, maintenance and repair account for the largest share of O and M costs. These costs include the following It must be noted that O and M costs in offshore wind turbines tend to be significantly higher than that of comparable land-based turbines because they are more difficult to...

Wind Turbine Tribological Components and Analysis

The tribological components in a wind turbine include rotor support bearings, intermediate gearbox rotor bearings, high-speed bearings, pitch bearings in the hub, epicyclic and parallel gears in the gearbox, a mechanical brake, a roller bearing system in the yaw mechanism, and slip rings in generator (if the generator is a doubly fed induction generator). It is widely accepted that bearing failure is one of the major issues in wind turbine drivetrain reliability, as the bearings must contend with cyclic and transient loading as well as alignment issues. Studies by Slootweg et al. 30 and Musial et al. 29 relate the start of most drivetrain failures to faulty bearings. A spherical or tapered roller bearing typically supports the main shaft of most modern wind turbines upwind of the gearbox with rear, non-locating support bearings inside the gearbox 29 . Spherical bearings have the advantage of allowing the bearing's inner and outer ring to be slightly askew with each other without...

Wind Turbine Design and Performance

Downwind Hawt

Wind turbines are generally classified into two categories horizontal-axis wind turbines (HAWTs) and vertical-axis wind turbines (VAWTs). VAWTs incorporate a vertically oriented rotor shaft, with drivetrain components located at their base. Early VAWT designs include Savonius, Darrieus, and Giromill, or H-bar designs (Fig. 18.3). Although VAWTs have shown to have advantages over HAWTs in that they are omnidirectional and their drivetrain components easily maintained, their installation heights are limited, and their blades are prone to cyclic fatigue. Because VAWTs are relatively uncommon among modern turbine designs, they will not be discussed in this manuscript. their potential to be exposed to greater wind speeds. The drivetrain components, generator, and associated systems are installed in a nacelle enclosure at the top of a tower, with the nacelle itself angled (yawed) to keep the rotor blades in the direction of the wind. Early wind turbines were designed to position the blades...

Wind Turbine Theory and Designs

The term wind turbine power systems (WTPS) denotes systems that extract kinetic energy from wind and convert it into usable electrical energy. Along these lines, the size and mechanical complexity of wind turbines can range from relatively small (e.g., household wind turbines) to large, offshore wind turbines. Regardless of the size, all wind turbines incorporate airfoil blades that are pitched into and pushed by the wind, causing rotational power that is ultimately transferred to a generator. 18.3.1 Wind Energy Considerations In the design process, a number of items about wind power must be considered, including the following Transient Wind Speed Wind speed can change significantly over a relatively short time thus turbines must be able to adapt to rapidly changing loads. Turbines must also be able to protect from over speed when wind speeds are beyond operating limits. Transient Wind Direction Because wind gusts can change direction quickly, wind turbines must be able to adapt to...

Wind Energy

Wind energy is a clean and natural source of energy. The world market for wind energy technologies has grown dramatically in recent years. Before 2000, a small number of European companies dominated the production of wind turbines but the situation substantially changed when wind power development in the U.S., China, and India substantially increased. Global wind power generating capacity has reached to 59,322 megawatts (MW) as of 2005 (GWEC 2006). This is 25 growth over one year period. Wind energy is the world's fastest-growing energy source on a percentage basis. The wind turbines installed in the year 2005 alone had a capacity of 11,769 MW (GWEC, 2006). Figure 5.9 shows the wind power capacity of the world's top ten wind producing countries. It was also reported in 2006 that by 2010, wind energy alone will save enough greenhouse gas emissions to meet one third of the European Union's Kyoto obligation (GWEC 2006). North America had the highest capacity installed in 2005, 37 higher...

Dry Deposition to Terrestrial and Aquatic Receptors

Dry deposition of Hg can occur via 2 processes 1) the direct deposition of gasphase Hg(0), and 2) the deposition of RGHg and, to a much lesser extent, atmospheric particulate matter to which Hg is reversibly or irreversibly adsorbed. The first process is extremely difficult to quantify, depending as it does on not only meteorological phenomena such as temperature and wind speed, but also on the type and geomorphology of the surface under consideration. Nevertheless, models and several recent chamber studies indicate that vegetation has the ability to absorb Hg(0) directly from the atmosphere (Lindberg et al. 1992 Hanson et al. 1995 Frescholtz 2002). However, to simplify the system, most regional scale studies have assumed that the gaseous flux of Hg(0) over the land water surface is zero (Pai et al. 1997 USEPA 1997 Bullock and Brehme 2002). Recently, a number of flux chamber experiments, especially on water surfaces, have been performed to test the validity of this assumption and to...

Carbon Nanotubes for Energy Storage

Energy is the integral part of human life since ancient time. In recent years, the world energy consumption has been increasing at a much faster rate due to growing population, modern lifestyle and rapid industrialization. Fossil fuels, nuclear power, wind energy, solar energy is some of the primary sources of energy. Clean technologies like solar energy, wind energy, hydro power, biomass energy, geothermal energy, tidal energy and wave power technologies are improving rapidly. The main problem of these technologies is that energy produced from these sources is difficult to store or transport. Significant amounts of electricity are lost while moving long distances on electric lines. It is obvious that an energy carrier is needed for all of these energy sources, which will be hydrogen. So, energy resources and environmental pollution are essential problems that are concerned with sustainable development and demand prompt solution. Hydrogen is considered to be an ideal energy source and...

Removing C02 from the Atmosphere

A few scientists have proposed removing carbon dioxide chemically from ambient air, for example, from high-speed winds used to turn wind turbines, using chemicals such as amines, already discussed, or some other chemical absorber. The practicality of chemically extracting carbon dioxide from air, in which its concentration is only 0.04 , compared to about 13 in power plant emissions, is yet to be determined.

Economic and Environmental Considerations

The most efficient and largest commercial wind turbines currently are the 2-MW units, three times larger than the models of the mid-1990s. Behemoths with huge, 120-m blades are under development they will deliver 5 MW. About 660 North American homes can be supplied with electricity from a 2-MW system on typical hot afternoons, when the power draw peaks due to air conditioner usage. By contrast, modern coal-fired power plants generate from 125 MW to 1000 MW, so hundreds of windmills would be required to replace the power generated by one coal-fired plant. In terms of energy payback the amount of time required to generate the energy used in constructing the unit that for wind is only 3-4 mondis. Carbon dioxide emissions from wind power are the smallest for any power source (see Figure 8-4). Of all the forms of renewable energy, wind power is the most economical. The cost of generating electricity using modern windmill technology and feeding it into existing power grids is now almost...

Mathematical Development Of Model

9.3 and 9.4), Qm is the pollutant source (mass time), sx sy is the horizontal dispersion coefficient (length), sz is the vertical dispersion coefficient (length), u is the wind velocity (length time), and Hr is the height of the release (length). Notice that the model is divided into two basic parts the mass of pollutant released, represented by the first term in the equation, and dispersion, characterized by the wind speed, the y and z coordinates that yield estimates of dispersion (mixing), and the height of the release above the Earth's surface. Input values for all of these parameters are relatively simple to estimate or measure using the techniques described earlier. Note that the longitudinal distance, x, is a part of the equation since you must select the x distance to obtain estimates of sx and oz. Ht Height of pollutant release is 30.0 m. us Stack exit velocity of gases is 0.80m sec. u Wind speed is 0.80m sec. d Inside stack diameter is 0.80 m. P Atmospheric pressure is...

Limitations Of Our Model

A highly variable parameter in determining mixing and pollutant transport is the wind velocity. Wind velocity is generally much more variable than is water velocity in a river or aquifer. The only way to handle large variations in wind velocity is, again, to use a numerical methods approach to model the system.

Entrepreneurship and Innovation

Pressure, NGO and stockholder activism, and growing scientific evidence that our prior assumptions about the economy-natural systems relationship are outdated. As a consequence, we see already existing growth markets and fast emerging markets across a range of the economy organic foods, wind power, hybrid vehicles, green building materials and design, and environmentally benign chemical compounds offered for a wide variety of applications. Critics may point to the small size of these markets, but the size of these markets is less important than their rate of growth and the increasing number and intensity of factors favoring their continued expansion. Strategic, revenue, and profitability opportunities are the most compelling reasons for corporations to look to these kinds of markets. Note that the markets listed cover food, electric power, transportation, shelter, and materials. They also are closely linked to and have positive spillover effects for air quality, health protection, and...

Transport and Partitioning

Volatilization of 2,4-DCP from water is expected to be slow and, therefore, not a major removal process from surface waters. Using the Henry's law constant, a half-life of 14.8 days was calculated for evaporation from a model river 1 meter deep with a current of 1 meter second and a wind velocity of 3 meters second, neglecting adsorption to sediment (Thomas 1982). The biological treatment of waste water containing 2,4-DCP has shown that none of the chemical is removed by stripping (Stover and Kincannon 1983). Volatilization from near-surface soil is also not expected to be a significant removal process.

Dispersion and Peak Concentration

Peak concentrations occur within a few km of the source. Figure 2 shows the variation of the peak concentration cmax (annual average), calculated by ISC for urban conditions with meteorological data for Paris. The value of cmax decreases strongly as the stack height is increased. By contrast to the value of cmax, its location does not vary much with stack height this comes about because of a complicated interplay between stack height, atmospheric stability classes and height of boundary layer. For this calculation Paris appears to be quite a representative choice the wind speeds are average, and the wind directions are relatively uniform.

Bearing Predictive Modeling

Wind turbine bearings are generally lubricated using grease or high-viscosity mineral or synthetic oil to minimize surface contact. Lubrication modes are generally classified according to one of three regimes boundary lubrication, elas-tohydrodynamic lubrication (EHL), and full film (i.e., hydrodynamic) lubrication. Bearing interfaces typically operate within the EHL regime due to the large applied loads. Because EHL tends to take place under high loads and or low sliding speeds, it is characterized by the interplay between the pressure-based elastic deformation of the contacting surfaces and the viscosity and density enhancements of the lubricant 42-45 . The lubricant itself experiences a sudden rise in pressure, from ambient to over 1 GPa, within the interface, causing (under ideal conditions) separation of the solid surfaces and minimizing of surface wear. The study of EHL has been extensively investigated by a number of researchers over the past half-century, as initiated by the...

Contamination Control

Strategies for ameliorating the harmful effects of oil contamination have been developed over the past 40 years in the construction, mining, agriculture, and aerospace industries, and some of the knowledge gained is currently being applied to the wind turbine industry. Some of the practices that are currently being recommended for the manufacture, assembly, and maintenance of wind turbines are listed in Table 18.5. Additionally, an appropriately designed oil filtration system is critical for minimizing the possibility of early gear or bearing failure. Most wind turbines incorporate one or more filtration systems to remove debris and contaminants from the lubricant. Inline filters, which are placed within the same circulation line as the delivery system, are now standard on most current turbines. To keep the gear oil cool, a heat exchanger is used prior to returning the filtered oil back to the gearbox, typically keeping the maximum oil temperature below 70 C 94 . Some turbines are...

Passive Sampler Development

Where ka is the mass transfer coefficient for the air boundary layer (ABL) and ke is the release or elimination rate constant. The effect of the magnitude of compound Kpa on time to equilibrium is underscored by the finding that polychlorinated biphenyl (PCB) congeners 28 and 153 required 7 and 217 days (d), respectively, to reach equilibrium with the 1 m thick EVA coated POG. The ABL was shown to control the uptake rates of SVOC vapors and thus wind speed and turbulence largely mediates exchange kinetics. To minimize flow-induced variability in exchange kinetics, Harner et al. (2003) designed and applied a deployment device that dampened flow differences. Clearly, the use of these samplers can be extended to outdoor air, assuming adequate analyte mass can be sampled for quantitation of trace to ultra-trace levels of HOC vapors.

Sampling And Analysis

Polyurethane Foam passive samplers are the most widely used media for the investigation of SVOCs in the atmosphere in PAS studies. The PUF samplers were designed to sorb only gas-phase organics, but particles will also deposit to some extent in the passive sampler. The geometry of the sampler housing generally limits the amount of particles reaching the sampling matrix. The sampler housing can not only help prevent the particle deposition but also reduce the dependence of sampling rate on meterological conditions such as precipitation and wind speed (Pozo et al. 2004). The use of passive sampling methods to monitor atmospheric concentrations has greatly increased. Passive samplers have been used to investigate the vertical (Moreau-Guigon et al. 2007 Li et al. 2009), temporal (Meijer et al. 2003 Motelay-Massei et al. 2005 Moreau-Guigon et al. 2007), and spatial (Meijer et al. 2003 Harner et al. 2006a Du et al. 2009) distribution of atmospheric POP concentrations. The utility of PASs...

Common Reclamation Methods and Reclamation Efficiency

Sprinkling leaching generally belongs to unsaturated leaching method because its water apply rate usually is lower than soil infiltration rate. Sprinkling leaching is more expensive but more efficient for salt leaching comparing with other methods (James et al., 1982). Similar to intermittent flooding leaching, sprinkling leaching usually uses less water to achieve the same degree of leaching in the same time period as compared with continual ponding leaching (James et al., 1982). Sprinkling leaching is suitable to unleveled field or regions where leaching water is scare or the drainage of saline water is constrained. However, wind speed is a limited factor for this method application.

Gear Dynamics and Wear

Scuffing Gears

A review by Errichello 51 classifies gear failure according to the categories of overload, bending fatigue, Hertzian fatigue, wear, and scuffing. The primary failure modes in wind turbine gears are generally scuffing, pitting, and abrasive wear, as discussed in the following sections. This failure mode is generally caused by hard contaminant particles that entrain into the interface. Particles that are introduced between sliding interfaces abrade material off each surface creating indentations. These indents create high local stresses and are the primary cause for surface-related fatigue failures 71 . Contaminant particles can be created during the manufacturing, assembly, or runin processes, be ingested from the environment through breathers or seals, or be internally generated. Further details on particulate contamination in wind turbine drivetrains are given in Sect. 18.6.2.

The Relation of Green Nano Tribology and Global Challenge 13 Energy

Innovations are accelerating concentrator photovoltaics that dramatically reduce costs waste heat from power plants, human bodies, and microchips to produce electricity genomics to create hydrogen-producing photosynthesis buildings to produce more energy than consumed solar energy to produce hydrogen microbial fuel cells to generate electricity and compact fluorescent light bulbs and light-emitting diodes to significantly conserve energy, as would nanotubes that conduct electricity. Solar farms can focus sunlight atop towers with Stirling engines and other generators. Estimates for the potential of wind energy continue to increase, but so do maintenance problems. Plastic nanotech photovoltaics printed on buildings and other surfaces could cut costs and increase efficiency. The transition to a hydrogen infrastructure may be too expensive and too late to affect climate change, while plug-in hybrids, flex-fuel, electric, and compressed air vehicles could provide alternatives to...

Contamination Effects

Gear oil recirculates through wind turbine gearboxes, lubricating mating surfaces and removing heat. Unfortunately, contaminant particles suspended in the gear oil, as well as water in the parts per million (ppm) range, can significantly degrade the performance and reliability of gearboxes. Sources of contaminant particles include cutting and grinding swarf built-in from manufacturing, ingression of airborne abrasives through vents and mechanical seals, and internally generated wear debris and metal oxide corrosion products. To quantify particulate contamination levels, the International Organization for Standardization (ISO) created cleanliness codes that serve as a universal standard for measuring and reporting contamination levels in fluids. Based upon a milliliter sample of lubricant, ISO codes are defined according to the nomenclature a b y, where a, b, and y denote the number of particles greater than 4, 6, and 14 im in size, respectively, per milliliter of lubricant. It can be...

Discussion of the Principles

5.3.2.5 Minimize Depletion of Natural Resources. Although there may be disagreement on the quantity of fossil reserves, there is general agreement that the reserves are limited. Thus, in order to promote sustainable designs, one must focus on the use of nonfossil reserves. Renewable resources should be promoted and used wherever technically and economically possible to replace products and processes that are derived from fossil resources. The use of renewable resources, however, should not occur without a concern for the level of reserves of these materials. In order to be truly sustainable, energy and material inputs must be derived from renewable resources at a rate that does not exceed the regenerative capacity of the ecosystem (Heusseman, 2004). If one consumes renewable resources at a rate that exceeds the regeneration rate, then renewable reserves will decline, and society will once again be faced with the need to identify new stocks of raw materials. For electricity generation,...

General Circulation Of The Atmosphere

When air moves between latitudes in which the speed of rotation is different, it is subject to the Coriolis effect, which gives the wind speed an unexpected component with respect to an observer on earth. For example, when a A simplified version of the actual prevailing wind patterns on the earth's surface is shown in Figure 2-6. These prevailing surface wind patterns are most noticeable over the oceans and were of great practical importance in the days of large sailing ships, when the major wind systems received their names. The doldrums near the equator and the horse latitudes were much feared by sailors, because a ship could remain becalmed there for weeks at a time. The various wind belts have a tendency to shift north and south at times, and the winds sometimes reverse because of topographical features, weather patterns, or simply the greater variability of some of these wind systems. The trade winds and the prevailing westerlies are fairly reliable, at least over the larger...

Bearing Dynamics and Wear

Micropitting Bearing

As discussed by a report by Kotzalas and Doll 35 , there exist a number of failure modes in wind turbine bearings. One of the most common wear modes is rolling contact fatigue, whose occurrence can often be attributed to the relatively large stresses that tend to appear below the surface of rolling elements. These subsurface stresses can produce cracks that form beneath the surface of the rolling elements or raceways, which then propagate to the surface, causing material to be removed from the surface and leaving behind small pits 36 (Fig. 18.15). Fretting wear can also occur within bearings, as wind gusts can cause the bearings to have low-amplitude motion while the system is shut down for maintenance 31 .

Sources of Cyanide and Nitriles 25231 Soil

Most of the cyanide in the atmosphere generally exists as hydrogen cyanide gas, and a small amount of metal cyanides may be present as particulate matter in air. The halflife for the reaction of hydrogen cyanide vapor with hydroxyl radicals in the atmosphere has been observed to be about 334 days. A relatively slow rate of degradation of hydrogen cyanide normally means that this compound has the potential to be transported over long distances before its removal by physical or chemical processes. Since hydrogen cyanide is miscible in water, its wet deposition on the surface may be the normal fate of this cyanide, as metal cyanide particles appear to be removed from air by both wet and dry deposition. Volatilization appears to be an important fate of hydrogen cyanide. At pH < 9.2, most of the free cyanide exists as hydrogen cyanide i.e. a volatile form of cyanide. The rate of volatilization of cyanide is affected by a number of parameters i.e. like temperature, pH, wind speed, and...

Surface Initiated Fatigue Spalling

Fatigue Spalling

The dynamic clearances between moving parts are on the order of 1 im, which is the same dimension as many hard contaminant particles. Hard particles trapped in rolling contacts indent raceway surfaces creating raised metal shoulders that act as stress risers 85-88 . The pressure increase around a dent can surpass the normal Hertzian pressure. During subsequent rolling cycles, tangential surface stress plus lubricant forced into the cracks cause the cracks to propagate beneath the surface. Cracks eventually undermined raceway surfaces, creating a fatigue spall (Fig. 18.24) in a similar manner as that described in Sect. 18.5.1.2. Copious quantities of wear-hardened steel are thus released as wear debris, which can lead to secondary damage if not quickly removed. As indicated by Fig. 18.25, hard ductile steel particles (including gear wear debris) are the most damaging. However, large quantities of any hard particle will seriously degrade the bearing life. This makes the wind turbine...

Recommended Oil Particle Filters

A detailed model of a wind turbine contamination control system is shown in Fig. 18.30. When available, full-flow filters rated at b5(c) C 1,000 are recommended. As shown in Fig. 18.31, bearing life can be extended 2-5 times simply by installing 5 im full-flow gear oil filters in place of the older, less-efficient 1025 im filters found in some wind turbine gearboxes. In addition, wear debris released by gear teeth, bushings, and some dynamic seals are diminished in clean oil maintained by 5 im filters, resulting in less abrasive wear. Full-flow filters also capture catalytic fresh metallic wear debris before passing into hot sections of the gearbox, reducing the rate of oil oxidation and extending oil life. A difficulty with older types of high-efficiency full-flow filters is excessive flow restriction (i.e., large pressure drop across the filter). This can be especially demanding when filtering high viscosity wind turbine gear oils. However, this problem has been solved with the...

Economic Sustainability of Nuclear Energy

Of electricity produced with other energy sources such as coal, natural gas, and wind energy gives a fairly good idea how the economics of the nuclear energy works. Table 16.1 shows a comparison of the cost per kilowatts of electricity generation from different energy sources. It is understandable that nuclear energy cannot compete with its non-nuclear counterparts.

Environmental Factors

The meteorological elements that have the most direct and significant effects on the distribution of air pollutants are wind speed and direction, solar radiation, stability, and precipitation. Therefore, it is important to have a continuing baseline of meteorological data, including these elements, to interpret and anticipate probable effects of air pollution emissions. Data on temperature, humidity, wind speed and direction, and precipitation are generally available through official government weather agencies. The National Weather Service (formerly U.S. Weather Bureau), Asheville, North Carolina, is a major source of information. Other potential sources of information are local airports, stations of the state fire weather service, military installations, public utilities and industrial complexes, and colleges and universities. For a particular area, the total effect of these various circulations establishes the hourly, daily, and seasonal variations in wind speed and direction. With...

Warming Exhalation Cycle

Water may also enter wind turbine gearboxes during maintenance activities or through external seals. A recommended practice for removing this water is to install a water absorbing cartridge in the off-line position. Externally these units appear similar to particle filters, but inside have quite different constructions. Some are made from porous cellulose-based materials with limited rates of removal and water holding capacity. Preferred units incorporate super-absorbent polymers (SAP) with 95 water removal efficiency that rapidly take out free water and also a portion of the dissolved water, as shown in Fig. 18.34. Finally, a proven technology known as dry air blankets has recently been adapted to wind turbines for water contamination removal. In this system, compressed air passes through a pressure swing absorber producing very dry air ( 40 C dew point). Flow is arranged so that a blanket of the dry air sweeps over the oil surface in the reservoir. Gear oil is continuously...

Douglas C Downey

Downey has over 30 years of engineering experience with an emphasis on developing and testing innovative remediation methods such as bioventing, monitored natural attenuation, biowalls and in situ bioreactors. He is currently developing sustainable remediation systems that operate on solar and wind power. Mr. Downey is a registered professional engineer in Colorado and has designed and completed over 300 remediation projects. Mr. Downey is working on several projects to establish clean drinking water supplies in developing nations.

Smallscale Climate

0n the average, urban climates are warmer and have more precipitation than the surrounding countryside. Table 3-3 compares an average city with the surrounding countryside for a number of climate elements. Note that a city is dirtier, cloudier, foggier, has more drizzly rain (precipitation days < 5 mm total), more snow, less sunshine, less wind, and higher temperatures than the surrounding countryside. Wind speed is lowered in the city, except near very tall buildings, where appreciably higher wind speeds have been found in specific cases. Annual mean wind speed The lower wind velocity in cities probably is caused by many obstacles (buildings) that are in the path of any wind in a city. The lack of standing water and the fast drainage of precipitation into storm drains result in a decrease of local evaporation and thus in the observed decrease of humidity in cities. However, when a city contains many cooling towers and there is generally a high water vapor output from burning of...

Energy

The diversification of energy sources tailored to the requirements and resources of each country using nature's renewable resources such as the sun (photovoltaics), wind power, geothermal energy and biomass is a definite requirement. If solar cells are chosen to provide an alternative to fossil fuels, significant research work is needed (i) to develop new routes for the production of crystalline silicon, (ii) in the development of amorphous silicon hybrid materials that could result in enhanced efficiencies, (iii) for further development of thin-layer technology, (iv) in concerted efforts for cheaper and more stable dyes, (v) in improving the efficiency of the dye-sensitized cells and (vi) in process development to deliver enhanced device performances, ensure sustainability and reduce production costs on an industrial scale.

Conclusions

The use of PRCs holds considerable promise for assessing the effects of wind speed and temperature on passive sampler performance. However, further work is required to show that PRCs can be used to correct for photodegradation. Therefore, samplers should be deployed in appropriately designed passive sampling chambers to minimize the effects of sunlight and wind on sampler performance. Further studies aimed at examining particle deposition on passive sampler surfaces are required for a better understanding of the mechanisms controlling the accumulation of particle-bound SOCs. In summary, considerable progress has been made towards the development of passive samplers and associated methodologies that permits reliable near-quantitative determinations of airborne chemicals.

Challenges

Data comparability between various passive sampling campaigns designed to measure SVOCs in the atmosphere has not been investigated. As described earlier, deriving absolute SVOC concentrations using passive methods can be problematic. Use of PRCs minimizes the error in the measurement of relative concentrations, which makes PAS a good approach for trackdown of atmospheric SVOC sources. Nevertheless, data comparability between PAS studies in which the samplers were deployed for different lengths of time, in different seasons, or in areas with widely varying meteorology (especially wind speed) is likely to be poor. Use of different adsorbents (e.g., PUF vs. XAD) is also likely to result in poor data comparability.

Suggested Reading

Study the dispersion tables for the urban and rural settings. How does an increase in wind velocity affect dispersion 1. Using the background example dataset in Fate , conduct a sensitivity analysis on dispersion in each direction by varying wind speed and cloud cover conditions. Height of initial release 45 m Stack exit velocity 1.2m sec Wind speed 3.33 m sec Inside stack diameter 1.5 m Mass of gas spilled 90,000,000g Wind speed 12m sec Height of release 2 m Atmospheric stability category C For a sensitivity analysis, change the wind speed to 1 m sec and atmospheric stability at B. Check your answers with Fate . Wind speed 6m sec

Lubrication Methods

The main shaft bearings are lubricated using either pressure-fed oil lubrication or grease lubrication. The pressure lubrication method uses a circulating oil delivery system that involves the use of pumps, valves, and pipes to supply oil to the bearing. This system is considered to be the most effective because the circulation system regulates the oil temperature while filtering contaminants and metallic wear particles from the oil. However, the complexity of the system and the possibility of lubricant leakage tend to make pressure lubrication impractical for the rotor bearings. For this reason, lubrication with grease is a suitable, low-maintenance alternative which does not require any delivery systems. Grease lubrication is thus used in the rotor bearings of some utility-scale wind turbines 28 .

Abrasive Wear

Because of difficulty, expense, and safety issues, wind turbine operators strive to minimize the frequency of gear oil changes. The enemy is oil degradation, which includes loss of additives, excessive accumulations of fine particles, and especially oil oxidation. This well-documented oxidation mechanism starts when oxygen atoms are incorporated into oil molecules producing chemically reactive free radicals, which in turn initiate chain reactions involving thousands of oil molecules and producing acids and polymeric compounds. The acids promote corrosion. The polymers are gummy substances that (1) thicken the oil, fostering filter bypassing and lubricant starvation during cold starts, (2) foul passages and flow controls, another source of lubricant starvation, and (3) coat and thermally insulate heat exchange surfaces, fostering excessive heat build-up and elevated temperatures during operation. The surfaces of fresh metal wear particles are catalytic, promoting the formation of free...

Hydrolysis

In addition to oxidation, wind turbine gear oils can degrade through the direct hydrolysis of ester-based additives. These types of additives are synthesized by reacting alcohols and acids to produce the required esters, along with water as a by-product. In operating systems, dissolved water drives the reaction in reverse, decomposing esters back into alcohols (mostly innocuous) and acids (quite harmful), along with depletion of the ester-based additives. Acids produced by hydrolysis promote corrosion and can also react with metals to produce fouling gels.

Water Control

Component life can be significantly extended by keeping gear oil dry. For example, as shown in Fig. 18.31, compared to typical water contamination levels of 400-500 ppm found in many wind turbine gearboxes, maintaining gear oil near Two approaches are normally used for minimizing water contamination in operating wind turbines

Condition Monitoring

Wind turbine condition monitoring systems allow early warnings of mechanical and electrical faults, which allow the operator to plan system repair before severe failure takes place 101 . Because early damage to components can oftentimes be detected while the turbine is still operational, repair work can be planned well in advance. This is considered to be of importance particularly in regard to offshore wind turbines, where bad weather conditions can prevent repair actions for several weeks 3 . Typical wind turbine sensors include those for measuring the following (1) rotor position and speed, (2) generator position and speed, (3) power output,

Closure

Wind turbine designs have evolved significantly since their inception and all indications point to continued growth in both installation rate and technological development. Wind turbines incorporate a number of tribological systems, including low-speed, intermediate-speed, and high-speed drivetrain gears and bearings, oscillatory pitch and yaw bearings, and a mechanical brake. As increasingly powerful wind turbines have been designed over the years, more attention has been paid towards solving the tribological challenges in wind turbine systems, although many challenges remain. In particular, advanced filtration technology is of upmost importance, as clean lubricant is crucial towards maximizing the lifetime of critical drivetrain components. It is also important to have a detailed understanding of the loads that are being applied to wind turbine tribological systems. Having this knowledge will aid in the selection of the most appropriate tribological component for each section of the...

Tidal Turbines

The HATT devices extract kinetic energy from the tidal flow through moving a lifting surface (blade or foil) connected to an electrical power generator. As tidal turbine developments lag those of wind turbines by about 15 years, considerable experience and knowledge is being transferred from wind turbines 3 as well as from the understanding of ship propellers 4 . Wood et al. 17 discussed the similarity and differences between the use modern wind turbines and HATT devices. Medium-sized wind turbines are operating routinely at similar power and or torque levels to the generic tidal device, so certain major components or subsystems (e.g. gearbox) could be translated into tidal current service with little or no modification. However, tidal turbines operate in very different conditions. For example, tidal current velocities are predictable over long timescales and are not subject to random excursions over these values, whereas wind velocity is correlated to a series of stochastic...

Biographies

El-Haggar's environmental consulting experience includes more than 40 environmental industrial audits for major industrial identities, 20 compliance action plans, and nine environmental impact assessments. In addition, he has extensive consulting experience in environmental engineering, environmental auditing, environmental impact assessment, environmental management systems, cleaner production, industrial ecology, energy management, hazardous and non-hazardous waste management, recycling, pollution prevention and waste minimization, zero pollution, biogas solar wind technology, community desert development, solid and industrial waste, and environmental assessment for the local government and private industries. Dr. El-Haggar is a member board member of 14 national and international societies in the area of mechanical engineering, environmental engineering, and community development.

Drivetrain Layout

Nacelle Component

The nacelle of the wind turbine is the external housing that contains the main mechanical components of the system. As shown in Fig. 18.7, these components include the rotor shaft and bearings, a gearbox assembly (if necessary), a lubricant filtration system, a mechanical braking system, a generator, and power electronics. The gearbox transmits power from the main shaft to a high-speed shaft, which, in turn, drives the generator. The drivetrain components and nacelle cover are mounted onto a bedplate, which in turn, is positioned on top of a yaw system that is designed to actively orient the rotor into the wind. Although a variety of wind turbine drivetrain designs are currently in use, all utility-scale designs generally fall within three main categories 27 . The first Fig. 18.7 Diagram of components in wind turbine nacelle Fig. 18.7 Diagram of components in wind turbine nacelle

Transient Loading

Transient Wind Speed

It must also be noted that wind turbines, unlike other forms of electricity production, are designed to generate under a spectrum of power levels 5 , and thus must contend with transient loads within their drivetrains. A commonly used means to estimate the power-producing ability and drivetrain loads is to assume that it operates under a certain wind speed distribution. The distributions that are frequently used are Weibull (Fig. 18.5) and Rayleigh distributions 23, 24 . To determine the number of cycles of a drivetrain component at a given load, it is important to determine the total number of hours per year for a particular wind speed. This is done by finding the probability of a particular wind speed for the desired distribution and multiplying it by the number of hours per year. The probability that the wind lies between two wind speeds is given by Fig. 18.5 Histogram of predicted and observed wind speeds, from 25 Fig. 18.5 Histogram of predicted and observed wind speeds, from 25...

Air Pollution

Air pollution is the presence of solids, liquids, or gases in the outdoor air in amounts that are injurious or detrimental to humans, animal, plants, or property or that unreasonably interfere with the comfortable enjoyment of life and property. Air pollution inside dwellings or places of assembly is discussed under Indoor Air Quality in Chapter 5, Environmental Emergencies and Emergency Preparedness by Pedro M. Armenante, James P. Mack in Environmental Engineering, Sixth Edition Prevention and Response To Water-, Food-, Soil-, and Air-Borne Disease And Illness. The composition of clean air is shown in Table 4.1. The effects of air pollution are influenced by the type and quantity of pollutants and their possible interactions* as well as wind speed and direction, typography, sunlight, precipitation, vertical change in air temperature, photochemical reactions, height at which pollutant is released, and susceptibility of the individual and materials to specific contaminants singularly...

Power Control

Active Stall

Ideally, a wind turbine should be able to extract as much power as possible up to the rated power of the generator, then limit the extracted power to the rated level as the wind speed increases further. Modern wind turbines are able to maintain the desired amount of power, in part, by controlling the pitch of the rotor blades. Rotor pitch control can take place using one of the following methods Fig. 18.6 Power characteristics of fixed-speed wind turbines under a stall control, b active stall control, and c pitch control, from 26 Fig. 18.6 Power characteristics of fixed-speed wind turbines under a stall control, b active stall control, and c pitch control, from 26 Passive stall-controlled The rotor blades are rigidly attached to the hub at a fixed angle. However, the geometry of the rotor blades are designed aerodynamically to ensure that the blades will stall (i.e., lose lift) when the wind speed exceeds a designated value. This feature serves to protect the turbine from overspeed....

Air Sampling Rates

No large variation in sampling rates is observed among the different studies, despite differences in exposure conditions, such as wind speeds, temperature, and SPMD mounting layout. It should be noted, however, that the effect of temperature is partially accounted for by our use of temperature-corrected log Koa values. An example of the application of Eq. 3.68 for calculating atmospheric concentrations is given in Box 3.3. by the Ockenden et al. (2001) observation that PCB amounts sampled by shielded SPMDs was slightly less than for fully exposed SPMDs (smaller than a factor of 1.5, depending on the compound). These authors conclude that the effect of wind speed on the sampling rates is insufficient to explain the earlier observation by Ockenden et al. (1998) that sampling rates were higher in winter than in summer, and that the increase of sampling rates at lower temperature implies membrane-controlled uptake.

Kitakyushu

A zero-emissions industrial park includes an aggregation of recycling plants consisting of small, midsize, and start-up businesses and a wind-power plant. The investment of 50 billion yen (around US 450 million) was 64 from private sector and 36 from public. One thousand workers are employed in the resource recovery industries at this site, including Energy from wind-power plant The energy is sold to Kyushu Electric Co., Inc.

Mechanical Brake

Modern wind turbines incorporate a mechanical brake on the high-speed section of the drivetrain, normally between the gearbox and the generator. This mechanical brake, which almost always is in the form of a disk brake, is primarily responsible for locking down the rotor during shutdown such that servicing and repair work can take place. Beyond functioning as a parking brake, some turbines employ the mechanical brake as a secondary braking system to complement aerodynamic braking during operation. On larger wind turbines, the mechanical brake is situated on the high-speed side of the gearbox to minimize the size and weight of the brake disk. Because of its position on the high-speed shaft, the use of the mechanical brake can be detrimental towards gearbox reliability. At standstill, braking loads oftentimes contend with forces from wind turbulence, causing small oscillatory movements of the gear teeth. These motions can result in fretting wear in the gear teeth 28 .

Receptor Models

Receptor Models Combining Meteorology with Measured Chemical Data. Several receptor models have been developed to locate atmospheric SVOC sources by combining meteorology with long-term measurements of chemical concentrations. Source locations of SVOCs have been investigated using regression models with local wind speed and direction parameters (Hillery et al. 1997 Cortes et al. 2000) or back air trajectories (Subhash et al. 1999). In all these studies, the back trajectories were calculated using the NOAA (National Oceanic and Atmospheric Administration) HYSPLIT (hybrid single-particle Lagrangian integrated trajectory) model a free and user-friendly resource. The HYPSLIT trajectories describe the advection of a single pollutant particle. Although the HYSPLIT trajectories can be augmented with dispersion models, in practice this has not been done because these studies focused on long-range transport. On long length scales (> 100 km), dispersion is negligible.

Gearbox

Utility-scale fixed-speed and variable-speed wind turbines rely upon a gearbox to increase the slow-moving, high-torque input from the rotor to the high-speed output that is required by the generator. The gearing ratio, G, for a wind turbine transmission is defined as follows where ngenerator is the rotational speed of the generator and nrotor is the rotational speed of the rotor, both in rpm. A wind turbine that incorporates a generator Although the electrical systems in wind turbine systems are generally most prone to failure, gearbox and components tend to be the costliest to maintain and replace 10, 57 thus gearbox reliability is considered a critical issue in wind turbine design and operation. Studies have shown that less-than-desired reliability in wind turbine gearboxes can be attributed to a number of different factors,

S ninL18

Because an increasingly negative slip causes increased generator torque while any positive slip causes the generator to behave like a motor, it is desirable to limit the magnitude of allowable slip such that the rotor speed is uniform within a tolerance of 1 . Wind turbines with asynchronous generators and direct grid connection must then operate within a relatively narrow speed range, such that they are referred to as fixed-speed wind turbines. Fixed-speed wind turbines often have two fixed speeds, as enabled by incorporating either two generators with different ratings and pole pairs or a single generator with two sets of windings 17 . The fixed speed system was the design used by Danish manufacturers between the 1980s and 1990s 18 , and is thus considered to be the ''traditional'' layout. A standard squirrel-cage induction generator, which has stator windings connected to the load excitation source and rotor windings consisting of electrically...

Renewable Energy

The tribology of renewable sources of energy is a relatively new field of tri-bology. Today, there are meetings and sessions devoted to the tribology of wind turbines at almost every tribology conference, and they cover certain issues specific for these applications. Unlike in the case of the biomimetic approach and environment-friendly lubrication, it is not the manufacturing or operation, but the very application of the tribological system which involves green issues, namely, environmentally friendly energy production. The following issues can be mentioned. 1. Wind power turbines have a number of specific problems related to their tri-bology, and constitute a well-established area of tribological research. These issues include water contamination, electric arcing on generator bearings, issues related to the wear of the mainshaft and gearbox bearings and gears, the erosion of blades (solid particles, cavitation, rain, hail stones), etc. 43 .

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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