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Climate change“Turbines and generatores”

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What Energies use a Turbine to

 produce Electricity?

Hydroelectric power 

Is a power source is used to turn a propeller-like piece called a turbine,which then turns a metal shaft in an electric generator , which is themotor that produces electricity.

Coal-Fired Plant power 

 A coal-fired power plant uses steam to turn the turbine blades; whereasa hydroelectric plant uses falling water to turn the turbine.

Wind power 

Is the use of air flow through wind turbines to mechanicallypower  generators for electricity. Wind power, as an alternative toburning fossil fuels, is plentiful, renewable, widely distributed, clean,produces no greenhouse gas emissions during operation, and useslittle land.[! "he net effects on the environment are far less problematicthan those of nonrenewable power  sources.

What Energies use a Generator to

 produce Electricity 

#ommon sources used to supply a generator with mechanical energyare$

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%. Wind

. &alling li'uid water 

(. )igh pressure steam.

"he fuels used to supply these forces are$

%. "he sun

. Wind

(. *ceans, rivers, and lakes

+. #oal

. *il, and natural gas

. uclear power 

/. An internal combustion engine.

Turbines

 A turbine is a simple device with few parts that uses flowing fluids0li'uids or gases1 to produce electrical energy. &luid is forced acrossblades mounted on a shaft, which causes the

shaft to turn. "he energy produced from theshaft rotation is collected by a generator which converts the motion to electricalenergy using a magnetic field.2ost power plants use turbines to produceenergy by burning coal or natural gas.

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"he heat produced from combustion is used to heat water in boiler. "heli'uid water is converted to steam upon heating and is e3haustedthrough a pipe which feeds the steam to the turbine. "he pressuri4edsteam flow imparts energy on the blades and shaft of the turbinecausing it to rotate. "he rotational mechanical energy is thenconverted to electrical energy using a generator.

TYPES OF HYDROPOWER TURBINES

"here are two main types of hydro turbines$ impulse and reaction. "hetype of hydropower turbine selected for a pro5ect is based on the heightof standing water6referred to as 7head76and the flow, or volume ofwater, at the site. *ther deciding factors include howdeep the turbine must be set, efficiency, and cost.

"erms used on this page are defined in the glossary.

IMPULSE TURBINE 

"he impulse turbine generally uses the velocity of the water to movethe runner and discharges to atmospheric pressure. "he water streamhits each bucket on the runner. "here is no suction on the down side of the turbine, and the water flows out the bottom of the turbine housing

after hitting the runner. An impulse turbine is generally suitable for highhead, low flow applications.

 

PELT!

 A pelton wheel has one or more free 5ets discharging water into anaerated space and impinging on the buckets of a runner. 8raft tubesare not re'uired for impulse turbine since the runner must be locatedabove the ma3imum tailwater to permit operation at atmosphericpressure.

 A "urgo Wheel is a variation on the 9elton and is made e3clusively by:ilkes in ngland. "he "urgo runner is a cast wheel whose shapegenerally resembles a fan blade that is closed on the outer edges. "hewater stream is applied on one side, goes across the blades and e3itson the other side.

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  C"##-FLW

 A cross-flow turbine is drum-shaped and uses an elongated,rectangular-section no44le directed against curved vanes on acylindrically shaped runner. It resembles a 7s'uirrel cage7 blower. "hecross-flow turbine allows the water to flow through the blades twice."he first pass is when the water flows from the outside of the blades tothe inside; the second pass is from the inside back out. A guide vane atthe entrance to the turbine directs the flow to alimited portion of the runner. "he cross-flow wasdeveloped to accommodate larger water flows andlower heads than the 9elton.

REACTION TURBINE 

 A reaction turbine develops power from the combined action ofpressure and moving water. "he runner is placed directly in the waterstream flowing over the blades rather than striking each individually.<eaction turbines are generally used for sites with lower head and higher flows than compared with the impulseturbines.

 

P"PELLE"

 A propeller turbine generally has a runner with three to si3 blades inwhich the water contacts all of the blades constantly. 9icture a boatpropeller running in a pipe. "hrough the pipe, the pressure is constant;if it isn=t, the runner would be out of balance. "he pitch of the bladesmay be fi3ed or ad5ustable. "he ma5or components besides the runnerare a scroll case, wicket gates, and a draft tube. "here are severaldifferent types of propeller turbines$

O

$%L$ T%"$&!E

"he turbine and generator are a sealed unit placed directly in the water stream.

O #T"'FL

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"he generator is attached directly to the perimeter of the turbine.

O T%$E T%"$&!E

"he penstock bends 5ust before or after the runner, allowing a straight

line connection to the generator.

O ('PL'!

>oth the blades and the wicket gates are ad5ustable,allowing for a wider range of operation.

  F"'!C&#

 A &rancis turbine has a runner with fi3ed buckets 0vanes1, usually nine

or more. Water is introduced 5ust above the runner and allaround it and then falls through, causing it to spin. >esidesthe runner, the other ma5or components are the scroll case,wicket gates, and draft tube.

  (&!ET&C

?inetic energy turbines, also called free-flow turbines, generateelectricity from the kinetic energy present in flowing water rather thanthe potential energy from the head. "he systems may operate in rivers,man-made channels, tidal waters, or ocean currents. ?inetic systems

utili4e the water stream=s natural pathway. "hey do not re'uire thediversion of water through manmade channels, riverbeds, or pipes,although they might have applications in such conduits. ?inetic systemsdo not re'uire large civil works; however, they can use e3istingstructures such as bridges, tailraces and channels.

HOW DO COAL-FIRED PLANTS WORK ?

%. )eat is created

>efore the coal is burned, it is pulveri4ed

to the fineness of talcum powder. It is

then mi3ed with hot air and blown into

thefirebo3 of the boiler. >urning in

suspension, the coal@air mi3ture provides

the most complete combustion and

ma3imum heat possible.

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. Water turns to steam

)ighly purified water, pumped through pipes inside the boiler, is turned

into steam by the heat. "he steam reaches temperatures of up to %,

degrees &ahrenheit and pressures up to (, pounds per s'uare

inch, and is piped to the turbine. (. Bteamturns the turbine

"he enormous pressure of the steam pushing against a series

of giant turbine blades turns the turbine shaft. "he turbine

shaft is connected to the shaft of the generator, where

magnets spin within wire coils to produce electricity.

+. Bteam turns back into water  After doing its work in the turbine, the steam is drawn into a condenser,a large chamber in the basement of the power plant. In this importantstep, millions of gallons of cool water from a nearby source 0such as ariver or lake1 are pumped through a network of tubes running throughthe condenser. "he cool water in the tubes converts the steam backinto water that can be used over and over again in the plant."he cooling water is returned to its source without any contamination,and the steam water is returned to the boiler to repeat the cycle.

WIND TURBINES

a wind turbine works the opposite of a fan. Instead of using electricity

to make wind, like a fan, wind turbines use wind to make electricity.

"he wind turns the blades, which spin a shaft, which connects to a

generator and makes electricity. Ciew the wind turbine animation to see

how a wind turbine works or take a look inside.

Wind is a form of solar energy and is a result of the uneven heating of

the atmosphere by the sun, the irregularities of the earth=s surface, andthe rotation of the earth. Wind flow patterns and speeds vary greatlyacross the Dnited Btates and are modified by bodies of water,vegetation, and differences in terrain. )umans use this wind flow, ormotion energy, for many purposes$ sailing, flying a kite, and evengenerating electricity.

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"he terms wind energy or wind power describe the process by whichthe wind is used to generate mechanical power or electricity. Windturbines convert the kinetic energy in the wind into mechanical power."his mechanical power can be used for specific tasks 0such as grindinggrain or pumping water1 or a generator can convert this mechanicalpower into electricity.

How a Generator works to produce

Electricity?

"he generator pictured above is a small and cylindrical turbine

generator with an outer casing made of steel.

%.- from the figure above, is a spinning rotor that is attached to theturbine shaft. "he main 5ob of the rotor is to absorb the mechanicalenergy outside the generator, and use it to create rotational motion."he rotor in a turbine generator could be attached to a set of windturbine blades, a set of reaction or impulse steam turbine blades,hydro-turbine blades, or a gas engine.

.-"he turbine shaft will begin to rotate with the rotor, causing all of theinner workings of the machine to rotate as well.

(.- Attached to the turbine shaft is a coil of copper wire that rotates atthe same speed as the turbine shaft and is often referred to as anarmature.

(.- *n either side of the armature, on the casing of the generator, wehave two polar field magnets that create a magnetic field inside the

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space within the generator. As the rotor, shaft, and armature rotate,they move within the electric field created by the magnets.

"he picture below shows the same generator from a different point of

view, as if you were looking lengthwise, down through the circular topof the turbine cylinder. 2ore easily seen from this view, the armaturerotates within the generator, with each end moving opposite the other. As one end rotates upward through the magnetic field, the oppositeside will be rotating downward, and eventually in a complete circle thatis repeated many times.

+. As the turbine rotates the armature through the magnetic field, anelectrical current is created within the copper coil of the armature.

"he current is created due to a law of electromagnetismcalled &aradayEs Faw of Induction, discovered in the %GEs. "his lawstates that a wire conductor that creates movement through a magneticfield creates an electric current, and that the strength of the current ise'ual to the rate of change through the magnetic field. Bo, the fasterthe copper coil rotates, the more electric current will be created.

. &inally, the electricity produced can be e3tracted from thegenerator. "he method of retrieving the electrical energydepends on how it will be used.

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ote$ in this particular case, we get electric energy produced from twodifferent directions 0as one coil is spinning up, the other is rotatingdownward1 so the electrical output comes as an alternating current.

In the figure below we see a graphical representation of an analternating current, where the electrical charge travels back and forthrepeatedly between and positive and negative charge$

"he information above is a brief overview of how a generator works. "he turbine inside the generator rotates from an source of mechanicalenergy, which causes the copper coil to rotate within a magnetic field,which produces an electric current. &ollow the links to apply yourknowledge of how a turbine generator works using each of theseforces$ Wind nergy, Bolar nergy, )ydro nergy, Bteam nergy.