A 

Abortion
Accounting
Advertising
Africa
African-American Studies
Aging
Agriculture
American Indian Studies
Anthropology
Archaeology
Architecture
Argumentative
Art: Artists (Alphabetized)
Art: General
Become an Affiliate and Earn $$$
Biographies (Alphabetized)
Book Reviews (Non-Fiction) (Alphabetized)
Business: Companies (Alphabetized)
Business: General
Business: Industries (Alphabetized)
Business: International
Business: Small
California
Canada
Caribbean
Child Abuse
China
Communication: Journalism
Communication: Language & Speech
Communication: Media
Communication: Non-Verbal
Communication: Television
Communication: Television & Children
Communism
Computer Science
Consumerism
Criminal Justice: General
Criminal Justice: Juvenile Delinquency
Criminal Justice: Police Science
Criminal Justice: Prisons
Cuba
Death & Dying: Euthanasia
Death & Dying: General
Death & Dying: Suicide
Drama: American
Drama: English
Drama: World
Drugs: Alcohol
Drugs: General
Economics: Banking
Economics: Economists (Alphabetized)
Economics: General
Economics: Inflation
Economics: International Trade
Economics: Macroeconomics
Economics: Microeconomics
Economics: Taxation
Education: Administration
Education: Curriculum
Education: General
Education: Higher
Education: Physical
Education: Psychology
Education: Reading
Education: Special
Education: Teaching Methods
Education: Theory
Energy: General
Energy: Nuclear
Energy: Solar
Environmental Studies
Evolution
Family & Marriage
Films: Artists (Alphabetized)
Films: General
Finance: Companies (Alphabetized)
Finance: General
Former Soviet Union: Post-1990
France
Gender & Sexuality
Geography
Germany
History: Ancient Greek & Roman
History: European
History: Great Britain
History: U.S. (After 1865)
History: U.S. (Before 1865)
History: U.S. Presidency
History: U.S. Presidents (Alphabetized)
Homosexuality
Immigration
India
Indonesia
International Relations: Arms Control
International Relations: Cold War
International Relations: Non-U.S.
International Relations: U.S.
Japan
Jewish Studies
Korea
Labor
Latin America
Law: Business
Law: Capital Punishment
Law: General
Law: International & Non-U.S.
Law: Supreme Court
Leadership
Literature, American: Authors (Alphabetized)
Literature, American: Faulkner
Literature, American: Fitzgerald
Literature, American: General
Literature, American: Hawthorne
Literature, American: Hemingway
Literature, American: Melville
Literature, American: Poe
Literature, American: Steinbeck
Literature, American: Twain
Literature, English: Authors (Alphabetized)
Literature, English: Chaucer
Literature, English: Conrad
Literature, English: Dickens
Literature, English: General
Literature, English: Joyce
Literature, English: Lawrence
Literature, English: Shakespeare
Literature, English: Swift
Literature, General: Children
Literature, General: Classic (Greek & Roman)
Literature, General: Russian
Literature, General: World
Management: General
Management: Japanese
Management: Motivation
Management: Theory
Management: Women
Marketing: Companies (Alphabetized)
Marketing: General
Marketing: Plans
Mathematics
Medical: Aids
Medical: Dentistry
Medical: Diseases & Disorders (Alphabetized)
Medical: General
Medical: Nursing
Mexican-American Studies
Mexico
Middle East: Egypt
Middle East: General
Middle East: O.P.E.C.
Military
Music: Classical
Music: General
Mythology
Nutrition
Parapsychology/Occult
Philosophy: Ancient Greek
Philosophy: Descartes
Philosophy: Eastern
Philosophy: General
Philosophy: Kant
Philosophy: Sartre
Poetry: American
Poetry: English
Poetry: Milton
Poetry: World
Political Science: Elections & Campaigns
Political Science: Foreign
Political Science: Lobbyists & Pressure Groups
Political Science: Machiavelli
Political Science: Mill
Political Science: Political Theory
Political Science: U.S.
Psychology: Behaviorism
Psychology: Child & Adolescent
Psychology: Disorders
Psychology: Dreams
Psychology: Experimental
Psychology: Freud
Psychology: General
Psychology: Jung
Psychology: Physiology
Psychology: Piaget
Psychology: Rogers
Psychology: Social
Psychology: Testing
Psychology: Therapies
Public Administration: General
Public Administration: Government Agencies (Alphabetized)
Racism
Real Estate
Recreation & Leisure
Religion: Eastern
Religion: General
Religion: Islam
Religion: The Bible
Research: Completed Studies (With Statistics & Results)
Research: Designs & Proposals
Research: Statistics & Methodology
Russia: Pre-1917 Revolution
Science: Astronomy
Science: Biology
Science: General
Science: Genetics
Sociology: Durkheim
Sociology: General
Sociology: Marx
Sociology: Social Problems
Sociology: Social Theory
Sociology: Social Welfare
Sociology: Weber
Soviet Union: 1917-1990
Sports: Drugs
Sports: General
Technology
Transportation: Automotive
Transportation: Aviation
Transportation: General
Transportation: Railroads
Urban Studies
Vietnam
Women Studies
 

WINDMILLS.   Term Paper ID:20382 Click to get this paper

Essay Subject: History & evolution from 644 A.D.to the 1990s. Purposes, technology, designs, theory, materials, efficiency, wind turbines.... More...

10 Pages / 2250 Words 6 sources, 12 Citations, OTHER Format $40.00 Return to List of Papers

Paper Abstract: History & evolution from 644 A.D.to the 1990s. Purposes, technology, designs, theory, materials, efficiency, wind turbines. Paper Introduction: Historically, wind energy conversion systems can be considered as one of man's earliest machines. Windmills, according to documentation, were used in Persia as early as 644 A.D. to grind grain (5:9). Mechanically, the Persian windmill was a development of the watermill--an earlier machine used for turning grains into flour--and it looked a little like one turned up on end. A vertical shaft was set in a square tower, with sails set at right angles to the shaft at its top end. The wind passed through slots in the tower on to the sails, allowing the shaft to turn, as well as any machinery set at the bottom end (2:13). Traditionally, this principle travelled with the prisoners of Ghengis Khan to China, where horizontal mills with matting sails, but without the enclosing tower, were used to drive irrigation machinery. The Chinese discovered that if the Text of the Paper: The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper. Hunt, V.D. A smaller angle operates it atfaster speeds. Similar to the wings of a plane, air passes over the surfaces of aturbine's airfoil-shaped blades. In these areas, turbines can haveeasier access to utility transmission lines that would connect them to thenational grid network. Small changes in wind speed result in largechanges in the kinetic energy produced and, therefore, in the powerdelivered by a wind turbine. As the wind increases, thegenerator increases its output, which is measured in kilowatts. The Middle Eastern windmill has always been very distinctive fromthe northern type, and the Spanish variety resembled the Middle Eastern andNorth African windmill rather than that of northern Europe. 1991 Jul.:56-57.2. As hot air risesand cool air sinks, the difference in atmospheric pressure brings cool,dense air flowing inland from the ocean into the low-pressure zones of thehot interior deserts and valleys. Before the wind can strike the sails at the correct angle to makethem turn, they must be brought to face the direction from which it isblowing. High wind speeds occur as the cool coastal air is funneled throughthe gaps and mountain passes. In France,there is a reference to a windmill in a deed dated 118 . Solar energy also works when it is neededmost: during hot, dry weather. Antonoff, M. Cut-in speed is theminimum speed at which the turbine begins producing power. Farewell to windmills. It may be able to finely adjust its operation parameters tomaximize output and minimize mechanical loads (1:57). Some of the older types of French mills still carry bars setup without hemlaths. Any speed. The Chinese discovered that if the sails were"feathered"--set at an angle to the shaft--the mill would turn continuouslyso that there was no need for the enclosing wall and slots to direct thewind on to the driving side of each sail as it passed the slot. Alternative sources: A status report. Future research will decide on whether it willbecome more cost effective as well as a more advanced for of energy. These openareas of unused land make it easier to install wind turbines that needabout an acre of land each. Pop. The components are also extremely costly toreplace. Each year, wind turbinesoperate approximately 3, to 5, hours (4:95). The bars protrude less on thesail's leading edge than on the trailing edge, and in many cases there areonly longitudinal boards--leading boards--in front of the whip. The stocks form a cross on the windshaft and carry the whips whichbear the framework of the sails. With the declining cost ofphotovoltaic cells used to convert sunlight into a steady flow ofelectricity, the solar-powered pump looks like a possible alternative toconventional pumping methods. Pop. A wind turbine is designed to operate under these varying conditionsaccording to its "cut-in" and "cut-out" speeds. Accordingto some experts, the ideal wind turbine would be one without a gearbox.The transmission is where the stopping forces and the driving forces meet,but if the gearbox was eliminated, then there would be a straight shaftinto the generator. The lift is the force thatpulls the blades in a circular motion to drive a three-phase inductiongenerator housed in the turbine's nacelle. San Gorgonio. Other experts think the windmill on the farm will be replaced by asolar panel. This causes them to turn, and thus rotating the axis,called a windshaft--upon which they are set. These sails consisted of a simple wooden cross mortisedthrough an axle or windshaft, with bars mortised through the stocks andsticking out at an equal distance on each side of them. The great Dutch polder mills, although thatchedrather than weatherboarded, had in principle the same basic woodenframework as the English smock mill, first appeared in the 16 s. The mortise inthe end of the windshaft was always a weak point, because water could getinto it causing rot and eventual breakage at this point of great strain.The invention of cast iron solved this problem. Frank, D. When bigger windmills were built, it wasrealized that stocks long and strong enough to take the whole sail were noteasily available, and separate whips were made to carry the bars. Situated in the only opening wherecool air blows in from the coast to replace the hot desert air, the windturbines extend for miles to the south, toward Mt. Windmills. The next development in design was the common sail which, withvariations of detail, is still in use. This cuts off the outerlower corner of the sail, thus reducing area and the power developed. In 189 , the first of the modern windmills for producing electricitywas built in Denmark. Beedell, S. As the wind strikes the angled sail, some of its force (called thetangential force) is exerted to push the sail away from it, so the sailturns. to grind grain (5:9). While amill need to go at a speed of at least 12 to 15 revolutions of thewindshaft per minute, in order to grind or pump efficiently, nothing isgained by it going too fast. The sail has lines or cords running down bothedges, and pointing lines attached at intervals lower down the trailingedge, so that the sail can be rolled and reefed. Later, the ends ofthe bars were mortised or bolted into longitudinal hemlaths to brace thewhole sail. Wind machines also played a significant role inrural America prior to the 193 s, when the Rural Electrification Act (REA)provided cheap, convenient electricity to farmers (5:9). Maintenance isimportant, just as it is for an automobile. These mountains create a windtunnel that the California Energy Commission estimates is the largestsingle wind resource area in the state, channeling 33 megawatts worth ofharnessable wind power--enough to meet the residential needs of a city thesize of San Francisco (4:41). Mechanically,the Persian windmill was a development of the watermill--an earlier machineused for turning grains into flour--and it looked a little like one turnedup on end. Cloth sails were laced in and out of the bars, one each side of thestock and tied on at both ends. Many prime wind sites in the GreatPlains and Rocky Mountains are not close to population centers. The whole of the body (of a post mill) or the cap (of a tower orsmock mill) is turned--or winded--by various means. Cast iron provided another means of fixing stock and sailsto windshaft. The 1 , -mile lifespan of a car equals2, hours of wind turbine operation at 5 mph. The "disc" described by the revolvingwhips is exactly at right angles to the wind, and the bars mortised throughthem--which carry the cloth sails or shutters, as the case may be--are setat an angle to this imaginary disc. Sails that turn too fast, however, create enormous stresses ofthrust and friction, which a mill could not sustain indefinitely. Wind power is among the cleanest and most competitive of renewableenergy sources. Historically, wind energy conversion systems can be considered as oneof man's earliest machines. A windmill works, to state the obvious, when the wind blows on thesails of a windmill. Sci. In Europe, the primitive, vertical-axis windmills of the Persianswere seen until the twelfth century, when almost simultaneously in Franceand England the horizontal-axis, or the Dutch-type windmill came intobeing. Wind also pushedthings in front of it, so it may have been simple enough to devise a smallwindmill on a tripod, using flat sails like long paddles. Drainage and irrigation mills were developed before grindingmills in some countries, such as Persia and China. InBritain, brick and stone tower millers mostly appear later. In conclusion, despite its expense, wind power is still a viablerenewable source of energy. Inside the turbine, the transmission increases the driveshaft's rateof 5 rpm to match the generator's 12 rpm. Thesewhips were bolted and clamped to the stocks and had several advantages. The clothsails are tied at the inner end or heel of the sail frame or attached torings on an iron rail. Omni1991 May:5 -52, 8 -81, 86-87.----------------------- 1 New ways of operating windmills were evolved during the Middle Ages.These came about by trial and error rather than design. Blowing in the wind. The iron-cross poll fixing made it possible to put on five, six, oreven eight sails, because it was easier to make a cross with that many armsthan to make complicated canisters. In1191, there is a record of a mill at Bishopstone, in Sussex. All threetypes continued to be built until the mill ceased to be an importantmachine. Windmills, according to documentation, wereused in Persia as early as 644 A.D. Nadis, S.; et al. In general, the greater the sail area, the stronger this force willbe and the faster the sails, and consequently the windshaft and machinery,will turn. 1991 Aug.:41-43, 95.5. Mills with more than four sails are morepowerful, but the weight stress and expense factors outweigh theadvantages. With a watermill,the principles were obvious and simple. Most wind turbines operate more hours per year than the average carwill during its entire lifetime. Cut-out windspeed is the maximum speed above which no power production is expected.The turbine's rotor blades must spin at a steady speed in order to output aconstant frequency of 6 Hz so it can tie into a utility's power grid.Extremely high winds can cause structural damage to the turbine becausegust higher than its design speed increase the torsional stresses on thedrivetrain. The pressure differential between the topand bottom surfaces creates aerodynamic lift. Inside the top of the mill,also on the windshaft, is the brake wheel, a big wheel with cogs on itwhich, by means of gearing, drives the millstones and all the subsidiarymachinery in the mill. Influenced by the terrain, wind speedincreases with height as it flows farther away from the surface.Therefore, significant changes occur over a ridge or hill, and mountainsummits cause the greatest amount of acceleration. Ifone sail broke, it could easily be replaced without disturbing its oppositenumber, or without having to be taken out of the windshaft. The earliest known illustration of an English windmill is in theWindmill Psalter (c. USA Today 1991 June:3.4. Most turbines in theSan Gorgonio Pass operate when the winds are between 14 and 5 mph (4:43). As the valleys and mountains heat up andcool off at different rates, they create predictable wind patterns. The proportion of the wind'senergy being used to generate electricity is controlled by the angle of theblades to the wind. For example, an increase in wind speedof only two miles per hour, from 1 miles per hour (mph) to 12 mphrepresents a 78 percent increase in power generation. According to the American Wind Energy Association,the states in order of greatest wind power potential are North Dakota,Texas, Kansas, Montana, Oklahoma, Minnesota, Iowa, Colorado, New Mexico,and Idaho (4:95). The large spacing also allows wildlifeto flourish in its natural habitat. Windmills with more than four sailsbecame common after this innovation (2:22). Sawmills were developed in Holland at the end of the sixteenthcentury. Department of Energy, the generation of 1.8 billionkilowatt hours of electricity displaces the equivalent of 3.3 millionbarrels of oil (4:42). 127 ). Historically, windmills have been used to pump water forcattle and other uses, but a solar-powered pump may now be feasible (3:3).The logic behind developing the solar-powered pumping system was that rangecattle may be excluded from wetlands in the future and ranchers will needan alternative source of water for them. By the end of the thirteenth century windmills were more common innorthern Europe, although it would be another 1 years before they wouldbe common in southern Europe, and two hundred years before they would befound in Spain and Asia Minor. Moving water pushed things infront of it, so it would push the paddles of a wheel set vertically orhorizontally in it, thus turning the axle of the wheel. Research is currently being done on building agenerator that can produce electricity at 5 rpm and at 48 volts of ACcurrent to go into the utility grid. Windpower. San Jacinto, and formiles to the north, toward Mt. A larger angle captures more wind, allowing theturbine to operate at slower wind speeds. Turbines will have adaptive control based onsensing wind conditions and on what it knows about its historical poweroutput. Traditionally, this principletravelled with the prisoners of Ghengis Khan to China, where horizontalmills with matting sails, but without the enclosing tower, were used todrive irrigation machinery. Mech. Even during cloudy days, these pumps willcontinue to function, pumping about 3, gallons daily. New York: Charles Scribner's Sons; 1975.3. The advantages of this method were that sails were independent ofeach other and that water would not lie up between cross and sail back, sothe junction would stay even drier than by using the canister. San Gorgonio Pass is one of three main windfarm locations inCalifornia--the other two being Altamont Pass, about 3 miles east of SanFrancisco, and Tehachapi Pass, about 75 miles northeast of Los Angeles.Altogether, these windfarms have installed more than 17, commercial windturbines, with a peak generating capacity of approximately 15 megawatts.According to the U.S. Possibly, the invention of the windmilloccurred quite separately and in various forms in all those differentplaces. New York: Van Nostrand ReinholdCompany; 1981.6. The smock mills, of Britain and Holland were amuch later development, appearing most likely in the fifteenth toseventeenth century. The wind passed through slots inthe tower on to the sails, allowing the shaft to turn, as well as anymachinery set at the bottom end (2:13). Therefore, essential to a turbine's design is controlling therotational speed of the blades (4:43). The sails were reefed by moving them intoward the middle like curtains. Wind technology's greatest potential in the United States is as acentralized supplier of electricity. A vertical shaft was set in a square tower, with sails set atright angles to the shaft at its top end. In Holland, they cameinto use after 14 , as soon as sea defenses and dams were built so thatpools and lakes could be drained. This, and many other later illustrations,showed simple post mills. In drainage mills, the drive is carried down to thebase of the mill and out to turn a big scoop wheel (2:19). Eventually itwould have been found that the best angle at which to fix the sails on thestocks would be somewhere about 2 degrees from the plane of the stocks.The earliest sails, therefore, were set up with a constant pitch of about2 degrees (2:19). In Holland, theearliest record is 1274 (2:13). An iron cross was attached to the windshaft, and sail backsor heavier whips were bolted directly to this, without stocks being used atall. Wind originates with the sun's uneven heating of the atmosphere,because of the varying typography of the earth's surface. Thesepatterns determine the most ideal location for a windfarm. In the future, researchers are looking toward designing wind turbineswith artificial intelligence. Since 1981, costs have dropped from 25 cents per kilowatt-hour to less than 1 cents, and reliability has increased from 6 to 95percent (6:87). A big casting, known as apoll end or canister, was fitted to the end of the windshaft, the stockswere fitted into this and the whole think was secured and tightened up withwedges clamps. According to the DOE, a major challenge to producing windturbines that are cost-competitive in more parts of the country is toimprove turbine designs so they last 2 to 3 years. In England, the earliest written record of a windmill is a rentalnote dated 1185 of a windmill in a village called Weedly, in Yorkshire. Being spaced far apart from each other allowsthe wind to rebuild its strength. To maximize output, wind turbines are designed to take advantage ofthese high wind speeds. Literature Cited1. However efficient windmills are as a source of energy,there are reasons why they are not more plentiful in the United States.For one thing, the fatigue life of a turbine's major components is onlyabout five years (4:95). If wind speed doubles, the turbine willproduce eight times as much power. Today's windmills are designed with the same principles as those ofthe past although they are much more efficient and generate more energy.For example, northwest of Palm Springs, California, along interstate 1 ,there are more than 4, windmills spinning from the force of the windthat rushes through San Gorgonio Pass. If this paper is not what you are looking for, you can search again: Search for: or Click here to request an essay written just for you.