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[[File:G2 front2.jpg|right|thumb|NASA G2 flywheel]]
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'''Flywheel energy storage''' ('''FES''') works by accelerating a rotor ([[flywheel]]) to a very high speed and maintaining the energy in the system as [[rotational energy]].  When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of [[conservation of energy]]; adding energy to the system correspondingly results in an increase in the speed of the flywheel.
This page provides supplementary chemical data on [[Chlorobenzene]]. <!-- remove nowiki tags and replace with proper wikilink -->


Most FES systems use electricity to accelerate and decelerate the flywheel, but devices that directly use mechanical energy are being developed.<ref name="Torotrak">[http://www.xtrac.com/pdfs/Torotrak_Xtrac_CVT.pdf Torotrak Toroidal variable drive CVT], retrieved June 7, 2007.</ref>
== Material Safety Data Sheet == <!-- KEEP this header, it is linked to from the infobox on the main article page -->


Advanced FES systems have rotors made of high strength carbon filaments, suspended by [[magnetic bearing]]s, and spinning at speeds from 20,000 to over 50,000 rpm  in a vacuum enclosure.<ref name="ScienceNews">{{Cite journal
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet ([[Material safety data sheet|MSDS]]) for this chemical from a reliable source and follow its directions. An external MSDS is available [http://cnl.colorado.edu/cnl/images/MSDS/msds%20-%20chlorobenzene.pdf here].
| last1 = Castelvecchi | first1 = Davide
| title = Spinning into control: High-tech reincarnations of an ancient way of storing energy
| doi = 10.1002/scin.2007.5591712010
| journal = Science News
| volume = 171
| issue = 20
| pages = 312–313
| date = May 19 2007
| url = http://sciencewriter.org/flywheels-spinning-into-control/
}}</ref> Such flywheels can come up to speed in a matter of minutes — much quicker than some other forms of energy storage.<ref name="ScienceNews"/>


== Main components ==
== Structure and properties == <!-- KEEP this header, it is linked to from the infobox on the main article page -->
[[File:Example of cylindrical flywheel rotor assembly.png|thumb|right|The main components of a typical flywheel.]]
A typical system consists of a rotor suspended by bearings inside a [[vacuum]] chamber to reduce friction, connected to a combination [[electric motor]] and [[electric generator]].


First generation flywheel energy storage systems use a large [[steel]] flywheel rotating on mechanical bearings. Newer systems use [[carbon-fiber]] composite rotors that have a higher [[tensile strength]] than steel but are an order of magnitude less heavy.<ref>[http://www.flybridsystems.com/F1System.html Flybrid System KERS using carbon fiber flywheel]</ref>
{| border="1" cellspacing="0" cellpadding="3" style="margin: 0 0 0 0.5em; background: #FFFFFF; border-collapse: collapse; border-color: #C0C090;"
! {{chembox header}} | Structure and properties
|-
| [[Index of refraction]], ''n''<sub>D</sub>
| 1.5241
|-
| [[Abbe number]]
|? <!-- Please omit if not applicable -->
|-  
| [[Dielectric constant]], ε<sub>r</sub>
| 5.6895 at 293.2 K
|-
| [[Bond strength]]
| ? <!-- Specify which bond. Please omit if not applicable -->
|-
| [[Bond length]]
| ? <!-- Specify which bond. Please omit if not applicable -->
|-
| [[Bond angle]]
| ? <!-- Specify which angle, e.g. Cl-P-O. Please omit if not applicable -->
|-
| [[Magnetic susceptibility]], χ<sub>m</sub>
| 69.5 x10<sup>-6</sup> cm<sup>3</sup> mol<sup>-1</sup>
|-
| [[Surface tension]], <math>\gamma</math>
| 34.78 dyn/cm at 10°C<br/>32.99 dyn/cm at 25°C<br/>30.02 dyn/cm at 50°C<br/>27.04 dyn/cm at 75°C<br/>24.06 dyn/cm at 100°C
|-
| [[Speed of Sound]]
| 1311 m/s at 20°C
|}


[[Magnetic bearing]]s are sometimes used instead of [[bearing (mechanical)|mechanical bearings]], to reduce [[friction]].
== Thermodynamic properties == <!-- KEEP this header, it is linked to from the infobox on the main article page -->


The expense of refrigeration led to the early dismissal of low temperature superconductors for use in magnetic bearings. However, [[high-temperature superconductivity|high-temperature superconductor]] (HTSC) bearings may be economical and could possibly extend the time energy could be stored economically.  Hybrid bearing systems are most likely to see use first.  High-temperature superconductor bearings have historically had problems providing the lifting forces necessary for the larger designs, but can easily provide a stabilizing force. Therefore, in hybrid bearings, permanent magnets support the load and high-temperature superconductors are used to stabilize it. The reason superconductors can work well stabilizing the load is because they are perfect [[diamagnet]]s.  If the rotor tries to drift off center, a restoring force due to [[flux pinning]] restores it. This is known as the magnetic stiffness of the bearing. Rotational axis vibration can occur due to low stiffness and damping, which are inherent problems of superconducting magnets, preventing the use of completely superconducting magnetic bearings for flywheel applications.
{| border="1" cellspacing="0" cellpadding="6" style="margin: 0 0 0 0.5em; background: #FFFFFF; border-collapse: collapse; border-color: #C0C090;"
! {{chembox header}} | Phase behavior
|-
| [[Triple point]]
| ? K (? °C), ? Pa
|-
| [[Critical point (chemistry)|Critical point]]
| 633.4 K (360.25°C), 4.52 MPa
|-
| [[Standard enthalpy change of fusion|Std enthalpy change<br/>of fusion]], Δ<sub>fus</sub>''H''<sup><s>o</s></sup>
| ? kJ/mol
|-
| [[Standard entropy change of fusion|Std entropy change<br/>of fusion]], Δ<sub>fus</sub>''S''<sup><s>o</s></sup>
| 9.6 J/(mol·K)
|-
| [[Standard enthalpy change of vaporization|Std enthalpy change<br/>of vaporization]], Δ<sub>vap</sub>''H''<sup><s>o</s></sup>
| 40.97 kJ/mol
|-
| [[Standard entropy change of vaporization|Std entropy change<br/>of vaporization]], Δ<sub>vap</sub>''S''<sup><s>o</s></sup>
| ? J/(mol·K)
|-
! {{chembox header}} | Solid properties
|-
| [[Standard enthalpy change of formation|Std enthalpy change<br/>of formation]], Δ<sub>f</sub>''H''<sup><s>o</s></sup><sub>solid</sub>
| ? kJ/mol
|-
| [[Standard molar entropy]],<br/>''S''<sup><s>o</s></sup><sub>solid</sub>
| ? J/(mol K)
|-
| [[Specific heat capacity]], ''c<sub>p</sub>''
| ? J/(mol K)
|-
! {{chembox header}} | Liquid properties
|-
| [[Standard enthalpy change of formation|Std enthalpy change<br/>of formation]], Δ<sub>f</sub>''H''<sup><s>o</s></sup><sub>liquid</sub>
| 11.1 kJ/mol
|-
| [[Standard molar entropy]],<br/>''S''<sup><s>o</s></sup><sub>liquid</sub>
| ? J/(mol K)
|-
| [[Specific heat capacity]], ''c<sub>p</sub>''
| 150.1 J/(mol K)
|-
! {{chembox header}} | Gas properties
|-
| [[Standard enthalpy change of formation|Std enthalpy change<br/>of formation]], Δ<sub>f</sub>''H''<sup><s>o</s></sup><sub>gas</sub>
| 52.0 kJ/mol
|-
| [[Standard molar entropy]],<br/>''S''<sup><s>o</s></sup><sub>gas</sub>
| ? J/(mol K)
|-
| [[Specific heat capacity]], ''c<sub>p</sub>''
| ? J/(mol K)
|-
| [[Van der Waals equation|Van der Waals' constants]]
| a = 25.8 L<sup>2</sup>bar/mol<sup>2</sup><br> b = 0.1454 L/mol
|-
! {{chembox header}} | Other properties
|-
| Std molar enthalpy of hydration of gas,<br/> Δ<sub>hyd</sub>''H''<sup>∞</sup> = Δ<sub>sol</sub>''H''<sup>∞</sup> - Δ<sub>vap</sub>''H''<sup><s>o</s></sup>
| -30.6 kJ/mol @ 298.15K
|-
|}


Since flux pinning is the important factor for providing the stabilizing and lifting force, the HTSC can be made much more easily for FES than for other uses. HTSC powders can be formed into arbitrary shapes so long as flux pinning is strong. An ongoing challenge that has to be overcome before superconductors can provide the full lifting force for an FES system is finding a way to suppress the decrease of levitation force and the gradual fall of rotor during operation caused by the [[flux creep]] of SC material.
==Vapor pressure of liquid==
{|
|-
|
{| border="1" cellspacing="0" cellpadding="6" style="margin: 0 0 0 0.5em; background: white; border-collapse: collapse; border-color: #C0C090;"
|-
| {{chembox header}} | '''P in Pa''' || 10 || 100 || 1k || 10k || 100k
|-
| {{chembox header}} | '''T in °C''' || -43 e || -17 e || 16.8 || 62.9 || 131.3
|}
e - extrapolated data
|}


== Physical characteristics ==
==Viscosity of liquid==
{{see also|Flywheel#Physics}}
{|
=== General ===
|-
Compared with other ways to store electricity, FES systems have long lifetimes (lasting decades with little or no maintenance;<ref name="ScienceNews"/> full-cycle lifetimes quoted for flywheels range from in excess of 10<sup>5</sup>, up to 10<sup>7</sup>, cycles of use),<ref name="Investire">[http://www.itpower.co.uk/investire/pdfs/flywheelrep.pdf Storage Technology Report, ST6 Flywheel]</ref> high [[energy density]] (100-130 W·h/kg, or 360-500 kJ/kg),<ref name="Investire"/><ref name="pddnet">{{cite web |title=Next-gen Of Flywheel Energy Storage |url=http://www.pddnet.com/article-next-gen-of-flywheel-energy-storage/ |publisher=Product Design &amp; Development |accessdate=2009-05-21}}</ref> and large maximum power output. The [[energy conversion efficiency|energy efficiency]] (''ratio of energy out per energy in'') of flywheels can be as high as 90%. Typical capacities range from 3&nbsp;[[kilowatt hour|kWh]] to 133&nbsp;kWh.<ref name="ScienceNews"/> Rapid charging of a system occurs in less than 15 minutes.<ref name="Distributed Energy">{{cite web |last=Vere |first=Henry |title=A Primer of Flywheel Technology |url=http://www.distributedenergy.com/may-june-2007/primer-flywheel-technology.aspx |publisher=Distributed Energy |accessdate=2008-10-06}}</ref>  The high energy densities often cited with flywheels can be a little misleading as commercial systems built have much lower energy density, for example 11 W·h/kg, or 40 kJ/kg.<ref name="Rosseta">[http://www.rosseta.de/texte/pdat-t4.pdf rosseta Technik GmbH, Flywheel Energy Storage Model T4], retrieved February 4, 2010.</ref>
|
{| border="1" cellspacing="0" cellpadding="6" style="margin: 0 0 0 0.5em; background: white; border-collapse: collapse; border-color: #C0C090;"
|-
| {{chembox header}} | '''T in °C''' || -25 || 0 || 25 || 50 || 75 || 100
|-
| {{chembox header}} | '''Viscosity in mPa s''' || 1.703 || 1.058 || 0.753 || 0.575 || 0.456 || 0.369
|}
|}


=== Energy density ===
==Thermal Conductivity of liquid==
The maximum energy density of a flywheel rotor is mainly dependent on two factors, the first being the rotor's geometry, and the second being the properties of the material being used. For single-material, isotropic rotors this relationship can be expressed as<ref>{{cite book|last=Genta|first=Giancarlo|title=Kinetic Energy Storage|year=1985|publisher=Butterworth & Co. Ltd.|location=London}}</ref>
{|
|-
|
{| border="1" cellspacing="0" cellpadding="6" style="margin: 0 0 0 0.5em; background: white; border-collapse: collapse; border-color: #C0C090;"
|-
| {{chembox header}} | '''T in °C''' || -25 || 0 || 25 || 50 || 75 || 100
|-
| {{chembox header}} | '''Conductivity in W/m K''' || 0.137 || 0.132 || 0.127 || 0.123 || 0.118 || 0.113
|}
|}


:<math>\frac{E}{m} = K\left(\frac{\sigma}{\rho}\right)</math>,<br />
where the variables are defined as follows:<br />
:<math>E</math> - kinetic energy of the rotor [J]<br />
:<math>m</math> - the rotor's mass [kg]<br />
:<math>K</math> - the rotor's geometric shape factor [dimensionless]<br />
:<math>\sigma</math> - the tensile strength of the material [Pa]<br />
:<math>\rho</math> - the material's density [kg/m^3]<br />


==== Geometry (shape factor) ====
== Spectral data == <!-- KEEP this header, it is linked to from the infobox on the main article page -->
The highest possible value for the shape factor of a flywheel rotor, is <math>K=1</math>,
which can only be achieved by the theoretical ''constant-stress disc'' geometry.<ref>{{cite journal|last=Genta|first=Giancarlo|title=Some considerations on the constant stress disc profile|journal=Meccanica|date=1989|volume=24|pages=235–248|doi=10.1007/BF01556455}}</ref> A constant-thickness disc geometry has a shape factor of <math>K=0.606</math>, while for a rod of constant thickness the value is <math>K=0.333</math>. A thin cylinder has a shape factor of <math>K=0.5</math>.


==== Material properties ====
{| border="1" cellspacing="0" cellpadding="3" style="margin: 0 0 0 0.5em; background: #FFFFFF; border-collapse: collapse; border-color: #C0C090;"
For energy storage purposes, materials with high strength, and low density are desirable. For this reason, composite materials are frequently being used, in advanced flywheels. The strength-to-density ratio of a material can be expressed in the units [Wh/kg], and values greater that 400 Wh/kg can be achieved by certain composite materials.
! {{chembox header}} | [[UV/VIS spectroscopy|UV-Vis]]
|-
| [[Lambda-max|λ<sub>max</sub>]]
| ? [[Nanometre|nm]]
|-
| [[Molar absorptivity|Extinction coefficient]], ε
| ?
|-
! {{chembox header}} | [[Infrared|IR]]
|-
| Major absorption bands
| ? cm<sup>&minus;1</sup>
|-
! {{chembox header}} | [[NMR Spectroscopy|NMR]]
|-
| [[Proton NMR]] <!-- Link to image of spectrum -->
| &nbsp;
|-
| [[Carbon-13 NMR]] <!-- Link to image of spectrum -->
| &nbsp;
|-
| Other NMR data <!-- Insert special data e.g. <sup>19</sup>F chem. shifts, omit if not used -->
| &nbsp;
|-
! {{chembox header}} | [[Mass Spectrometry|MS]]
|-
| Masses of <br>main fragments
| &nbsp; <!-- Give list of major fragments -->
|-
|}


==== Composite rotors ====
== References ==
Several modern flywheel rotors are made from composite materials. Examples include the ''Smart Energy 25'' flywheel from Beacon Power Corporation,<ref>{{cite web|title=Smart Energy 25 Flywheel|url=http://www.beaconpower.com/products/smart-energy-25.asp|accessdate=2012-04-29}}</ref> and the ''PowerThru'' flywheel from Phillips Service Industries.<ref>{{cite web|title=PowerThru flywheel|url=http://www.power-thru.com/flywheel_ups_technology.html|accessdate=2012-04-29}}</ref>
<references/>


For these rotors, the relationship between material properties, geometry and energy density can be expressed by using a weighed-average approach.<ref>{{cite web|last=Janse van Rensburg|first=P.J.|title=Energy storage in composite flywheel rotors|url=http://hdl.handle.net/10019.1/17864|publisher=University of Stellenbosch}}</ref>
*{{cite book|author=D. R. Lide|title=CRC Handbook of Chemistry and Physics 89th edition|publisher=CRC press|year=2009}}


== Applications ==
<!-- [http://webbook.nist.gov/chemistry/ NIST Standard Reference Database] -->
=== Transportation ===
====Road====
In the 1950s, flywheel-powered buses, known as [[gyrobus]]es, were used in [[Yverdon]], [[Switzerland]] and there is ongoing research to make flywheel systems that are smaller, lighter, cheaper and have a greater capacity.  It is hoped that flywheel systems can replace conventional chemical batteries for mobile applications, such as for electric vehicles.  Proposed flywheel systems would eliminate many of the disadvantages of existing battery power systems, such as low capacity, long charge times, heavy weight and short usable lifetimes. Flywheels may have been used in the experimental [[Chrysler Patriot]], though that has been disputed.<ref>[http://www.allpar.com/model/patriot.html Allpar - The Chrysler Patriot]</ref>


During the 1990s, [[Rosen Motors]] developed a [[gas turbine]] powered [[hybrid vehicle drivetrain#Series hybrid|series hybrid]] automotive powertrain using a 55,000 rpm flywheel to provide bursts of acceleration which the small gas turbine engine could not provide.  The flywheel also stored energy through [[regenerative braking]].  The flywheel was composed of a [[titanium]] hub with a [[carbon fiber]] cylinder and was [[gimbal]]-mounted to minimize adverse gyroscopic effects on vehicle handling.  The prototype vehicle was successfully road tested in 1997 but was never mass-produced.<ref name="Wakefield">{{cite book |title=History of the Electric Automobile: Hybrid Electric Vehicles |last=Wakefield |first=Ernest |year=1998|publisher=SAE|isbn=0-7680-0125-0|pages=332}}</ref>
[[Category:Chemical data pages]]
 
====Rail vehicles====
Flywheel systems have also been used experimentally in small [[electric locomotive]]s for shunting or [[switcher|switching]], e.g. the [[Sentinel Waggon Works|Sentinel-Oerlikon Gyro Locomotive]].  Larger electric locomotives, e.g. [[British Rail Class 70 (electric)|British Rail Class 70]], have sometimes been fitted with flywheel boosters to carry them over gaps in the [[third rail]]. Advanced flywheels, such as the 133&nbsp;kW·h pack of the [[University of Texas at Austin]], can take a train from a standing start up to cruising speed.<ref name="ScienceNews"/>
 
The [[Parry People Mover]] is a [[railcar]] which is powered by a flywheel. It was trialled on Sundays for 12 months on the [[Stourbridge Town Branch Line]] in the [[West Midlands (county)|West Midlands]], [[England]] during 2006 and 2007 and was intended to be introduced as a full service by the train operator [[London Midland]] in December 2008 once two units had been ordered. In January 2010, both units are in operation.<ref>{{cite web|url=http://www.londonmidland.com/index.php/news/news_items/view/23|title=Parry People Movers for Stourbridge branch line|date=2008-01-03|accessdate=2008-03-19|publisher=[[London Midland]] |archiveurl=http://web.archive.org/web/20080517110918/http://www.londonmidland.com/index.php/news/news_items/view/23 <!-- Bot retrieved archive --> |archivedate=2008-05-17}}</ref>
 
====Rail electrification====
FES can be used at the lineside of electrified railways to help regulate the line voltage thus improving the acceleration of unmodified electric trains and the amount of energy recovered back to the line during [[regenerative braking]], thus lowering energy bills.<ref>{{cite web|url=http://www.railwaygazette.com/nc/news/single-view/view/high-speed-flywheels-cut-energy-bill.html
|title=High-speed flywheels cut energy bill|date=2001-04-01|accessdate=2010-12-02|publisher=[[Railway Gazette International]]}}</ref>  Trials have taken place in London, New York, Lyon and Tokyo,<ref>{{cite web|url=http://www.railwaygazette.com/nc/news/single-view/view/kinetic-energy-storage-wins-acceptance.html |title=Kinetic energy storage wins acceptance|date=2004-04-01|accessdate=2010-12-02|publisher=[[Railway Gazette International]]}}</ref> and [[New York MTA]]'s [[Long Island Rail Road]] is now investing $5.2m in a pilot project on LIRR's [[West Hempstead Branch]] line.<ref>{{cite web|url=http://www.railwaygazette.com/nc/news/single-view/view/new-york-orders-fly-wheel-energy-storage.html |title=New York orders flywheel energy storage|date=2009-08-14|accessdate=2011-02-09|publisher=[[Railway Gazette International]]}}</ref>
 
=== Uninterruptible power supplies ===
Flywheel power storage systems in production as of 2001 have storage capacities comparable to batteries and faster discharge rates.  They are mainly used to provide load leveling for large battery systems, such as an [[uninterruptible power supply]] for data centers as they save a considerable amount of space compared to battery systems.<ref>{{cite web|url=http://www.datacenterknowledge.com/archives/2007/Jun/26/flywheels_gain_as_alternative_to_batteries.html.|title=Flywheel gains as alternative to batteries}}</ref>
 
Flywheel maintenance in general runs about one-half the cost of traditional battery UPS systems. The only maintenance is a basic annual preventive maintenance routine and replacing the bearings every five to ten years, which takes about four hours.<ref name="Distributed Energy"/> Newer flywheel systems completely levitate the spinning mass using maintenance-free [[magnetic bearing]]s, thus eliminating mechanical bearing maintenance and failures.<ref name="Distributed Energy"/>
 
Costs of a fully installed flywheel UPS are about $330 per [[kilowatt]].<ref>http://www.claverton-energy.com/active-power-article-flywheel-energy-storage.html</ref> In combination with a diesel generator set or integrated design, it supplies continuous power as long as there is fuel.
 
=== Laboratories ===
A long-standing niche market for flywheel power systems are facilities where circuit-breakers and similar devices are tested: even a small household circuit-breaker may be rated to interrupt a current of 10,000 or more amperes, and larger units may have [[breaking capacity|interrupting ratings]] of 100,000 or 1,000,000 amperes.  The enormous transient loads produced by deliberately forcing such devices to demonstrate their ability to interrupt simulated short circuits would have unacceptable effects on the local grid if these tests were done directly from building power.  Typically such a laboratory will have several large motor-generator sets, which can be spun up to speed over some minutes; then the motor is disconnected before a circuit breaker is tested.
 
Other similar high power applications are in [[tokamak]] fusion (like the [[Joint European Torus]]) and [[laser]] experiments, where very high currents are also used for very brief intervals. JET has two 775 ton flywheels that can spin up to 225 rpm.<ref>{{cite web |url=http://www.jet.efda.org/jet/news/2010/03/week-20/ |title=Week 20: JET Experiments: sensitive to TV schedules}}</ref>
 
=== Amusement rides ===
The [[Incredible Hulk Coaster|Incredible Hulk roller coaster]] at [[Islands of Adventure|Universal's Islands of Adventure]] features a rapidly accelerating uphill launch as opposed to the typical gravity drop. This is achieved through powerful [[traction motor]]s that throw the car up the track. To achieve the brief very high current required to accelerate a full coaster train to full speed uphill, the park utilizes several motor generator sets with large flywheels. Without these stored energy units, the park would have to invest in a new substation and risk [[Brownout (electricity)|browning-out]] the local energy grid every time the ride launches.
 
=== Pulse power ===
Since FES can store and release energy quickly, they have found a niche providing pulsed power (see [[compulsator]]).
 
=== Motor sports ===
[[File:Flybrid Systems Kinetic Energy Recovery System.jpg|thumb|right|A Flybrid Systems Kinetic Energy Recovery System built for use in Formula One]]
The [[Fédération Internationale de l'Automobile|FIA]] has re-allowed the use of KERS (see [[kinetic energy recovery system]]) as part of its [[Formula One]] 2009 Sporting Regulations.<ref name="FIA">[http://www.fia.com/resources/documents/1151088479__2009_F1_TECHNICAL_REGULATIONS.pdf F1 technical regulations]</ref> which is now back in for the 2011 Formula 1 season. Using a [[continuously variable transmission]]  (CVT), energy is recovered from the drive train during braking and stored in a flywheel.  This stored energy is then used during acceleration by altering the ratio of the CVT.<ref>[http://www.flybridsystems.com/Technology.html - Flybrid Systems]</ref> In motor sports applications this energy is used to improve acceleration rather than reduce carbon dioxide emissions—although the same technology can be applied to road cars to improve fuel efficiency.<ref>[http://www.flybridsystems.com/Roadcar.html - Flybrid Systems, Road Car Application]</ref>
 
[[Automobile Club de l'Ouest]], the organizer behind the annual [[24 Hours of Le Mans]] event and the [[Le Mans Series]], is currently "studying specific rules for [[Le Mans prototype|LMP1]] which will be equipped with a kinetic energy recovery system."<ref>{{cite web |url=http://www.lemans.org/sport/sport/reglements/ressources/auto_2008/cdc_reglement_lmp_fr_gb_2008.pdf |format=PDF |title=ACO Technical Regulations 2008 for Prototype "LM"P1 and "LM"P2 classes, page 3|publisher=Automobile Club de l'Ouest (ACO) |date=2007-12-20 |accessdate=2008-04-10 }} {{Dead link|date=October 2010|bot=H3llBot}}</ref>
 
=== Grid energy storage ===
{{anchor|Frequency regulation}}<!-- old section name after rename -->
{{main|Grid energy storage}}
[[Beacon Power]] opened a 20 MW, (5 MWh over 15 mins)<ref name="Beacon2"/> flywheel energy storage plant in [[Stephentown, New York]] in 2011.<ref>[http://phx.corporate-ir.net/phoenix.zhtml?c=123367&p=irol-newsArticle&ID=1576441&highlight= Beacon Power Flywheel Plant in Stephentown Reaches Full 20 MW Capacity]</ref>  Lower carbon emissions, faster response times and ability to buy power at off-peak hours are among some advantages of using flywheels instead of traditional sources of energy for peaking power plants.<ref>[http://www.beaconpower.com/products/EnergyStorageSystems/docs/BeaconPower_solutions_grid.pdf Flywheel-based Solutions for Grid Reliability]</ref>
 
=== Wind turbines ===
Flywheels may be used to store energy generated by wind turbines during off-peak periods or during high wind speeds.
 
Beacon Power recently began testing of their Smart Energy 25 (Gen 4) flywheel energy storage system at a wind farm in Tehachapi, California. The system is part of a wind power/flywheel demonstration project being carried out for the California Energy Commission (Beacon Power Press Release March 2010).
 
=== Toys ===
[[Friction motor]]s used to power many [[toy car]]s, trucks, trains, action toys and such, are simple flywheel motors.
 
=== Toggle action presses ===
In industry, toggle action presses are still popular.  The usual arrangement involves a very strong [[crankshaft]] and a heavy duty connecting rod which drives the tup. Large and heavy flywheels are driven by electric motors but the flywheels only turn the crankshaft when clutches are activated.
 
== Advantages and disadvantages ==
Flywheels are not as adversely affected by temperature changes, can operate at a much wider temperature range, and are not subject to many of the common failures of chemical [[rechargeable battery|rechargeable batteries]].<ref>http://www.mpoweruk.com/lithium_failures.htm</ref>  Unlike [[lithium ion polymer batteries]] which operate for a finite period of roughly 36 months, a flywheel can potentially have an indefinite working lifespan. Flywheels built as part of [[James Watt]] [[steam engines]] have been continuously working for more than two hundred years.<ref>{{cite web |url=http://www.powerhousemuseum.com/collection/database/?irn=7177 |title=Boulton and Watt steam engine |author=Powerhouse Museum |accessdate=2 August 2012 |publisher=Powerhouse Museum, Australia}}</ref> Working examples of ancient flywheels used mainly in milling and pottery can be found in many locations in Africa, Asia, and Europe.<ref>{{Cite journal
| last1 = Donners | first1 = K.
| last2 = Waelkens | first2 = M.
| last3 = Deckers | first3 = J.
| title = Water Mills in the Area of Sagalassos: A Disappearing Ancient Technology
| journal = Anatolian Studies
| volume = 52
| pages = 1–17
| year = 2002
| doi = 10.2307/3643076
}}</ref><ref>{{Cite journal
| last1 = Wilson | first1 = A.
| title = Machines, Power and the Ancient Economy
| journal = The Journal of Roman Studies
| volume = 92
| pages = 1–32
| year = 2002
| doi = 10.2307/3184857
}}</ref> They are also less potentially damaging to the environment, being largely made of [[inert]] or benign materials. Another advantage of flywheels is that by a simple measurement of the rotation speed it is possible to know the exact amount of energy stored. However, use of flywheel accumulators is currently hampered by the danger of explosive shattering of the massive wheel due to overload.
 
One of the primary limits to flywheel design is the tensile strength of the material used for the rotor.  Generally speaking, the stronger the disc, the faster it may be spun, and the more energy the system can store.  When the tensile strength of a flywheel is exceeded the flywheel will shatter, releasing all of its stored energy at once;  this is commonly referred to as "flywheel explosion" since wheel fragments can reach kinetic energy comparable to that of a bullet. Consequently, traditional flywheel systems require strong containment vessels as a safety precaution, which increases the total mass of the device. Fortunately, composite materials tend to disintegrate quickly to red-hot powder once broken, instead of large chunks of high-velocity shrapnel. Still, many customers of modern flywheel energy-storage systems prefer to have them embedded in the ground to halt any material that might escape the containment vessel.
 
An additional limitation for some flywheel types is energy storage time.  Flywheel energy storage systems using mechanical bearings can lose 20% to 50% of their energy in 2 hours.<ref name="Rosseta2">[http://www.rosseta.de/srsy.htm rosseta Technik GmbH, Flywheel Energy Storage, German], retrieved February 4, 2010.</ref>  Much of the friction responsible for this energy loss results from the flywheel changing orientation due to the rotation of the earth (a concept similar to a [[Foucault pendulum]]).  This change in orientation is resisted by the gyroscopic forces exerted by the flywheel's angular momentum, thus exerting a force against the mechanical bearings.  This force increases friction.  This can be avoided by aligning the flywheel's axis of rotation parallel to that of the earth's axis of rotation.
 
Conversely, flywheels with magnetic bearings and high vacuum can maintain 97% [[mechanical efficiency]], and 85% round trip efficiency.<ref name="Beacon2">[http://www.beaconpower.com/files/Flywheel_FR-Fact-Sheet.pdf Beacon Power Corp, Frequency Regulation and Flywheels fact sheet], retrieved July 11, 2011.</ref>
 
When used in vehicles, flywheels also act as [[gyroscope]]s, since their [[angular momentum]] is typically of a similar order of magnitude as the forces acting on the moving vehicle. This property may be detrimental to the vehicle's handling characteristics while turning. On the other hand, this property could be utilized to keep the car balanced so as to keep it from rolling over during sharp turns. Conversely, the effect can be almost completely removed by mounting the flywheel within an appropriately applied set of [[gimbal]]s, where the angular momentum is conserved without affecting the vehicle (see [[gyroscope#Properties|''Properties'' of a gyroscope]]). This doesn't avoid the complication of [[gimbal lock]], and so a compromise between the number of [[gimbal]]s and the angular freedom is needed. A single gimbal, for instance, could free a car for the 360 degrees necessary for regular driving. However, for instance driving up-hill would require a new gimbal mechanism with a new degree of freedom. Two gimbals would theoretically solve this problem and never lock unless the car rolls.
 
An alternative solution to the problem is to have two joined flywheels spinning synchronously in opposite directions. They would have a total angular momentum of zero and no gyroscopic effect. A problem with this solution is that when the difference between the momentum of each flywheel is anything other than zero the housing of the two flywheels would exhibit torque. Both wheels must be maintained at the same speed to keep the angular velocity at zero. Strictly speaking, the two flywheels would exert a huge [[torque]]ing moment at the central point, trying to bend the axle. However, if the axle were sufficiently strong, no gyroscopic forces would have a net effect on the sealed container, so no torque would be noticed.
 
== See also ==
{{Portal box|Sustainable development|Energy}}
 
* [[Energy storage]]
* [[List of energy topics]]
* [[Compensated pulsed alternator]]
* [[Grid energy storage]]
* [[Launch loop]]
* [[Plug-in hybrid]]
* [[Rechargeable battery]]
* [[Regenerative brake]]
* [[Electric double-layer capacitor]]
* [[Rotational energy]]
 
==References==
{{Reflist|2}}
 
==Further reading==
* Beacon Power Applies for DOE Grants to Fund up to 50% of Two 20 MW Energy Storage Plants, Sep. 1, 2009 [http://phx.corporate-ir.net/phoenix.zhtml?c=123367&p=irol-newsArticle&ID=1326376&highlight=]
* {{cite book
|last=Sheahen |first=T., P.  |year=1994
|title=Introduction to High-Temperature Superconductivity
|publisher=Plenum Press |location=New York |pages=76–78, 425–431
|isbn=0-306-44793-2
}}
* {{cite book
|last=El-Wakil |first=M., M.  |year=1984
|title=Powerplant Technology
|publisher=McGraw-Hill |pages=685–689
}}
* {{cite journal
|last=Koshizuka |first=N.
|coauthors=Ishikawa, F.,Nasu, H., Murakami, M., Matsunaga, K., Saito, S., Saito, O., Nakamura, Y., Yamamoto, H., Takahata, R., Itoh, Y., Ikezawa, H., Tomita, M.
|year=2003
|title=Progress of superconducting bearing technologies for flywheel energy storage systems
|journal=Physica C
|issue=386 |pages=444–450
}}
* {{cite journal
|last=Wolsky |first=A., M.  |year=2002
|title=The status and prospects for flywheels and SMES that incorporate HTS
|journal=Physica C
|issue=372–376 |pages=1495–1499
}}
* {{cite journal
|last=Sung |first=T., H.
|coauthors=Han, S., C., Han, Y., H., Lee, J., S., Jeong, N., H., Hwang, S., D., Choi, S.,  K. |year=2002
|title=Designs and analyses of flywheel energy storage systems using high-Tc superconductor bearings
|journal=Cryogenics |volume=42 |pages=357–362
|doi=10.1016/S0011-2275(02)00057-7
|issue=6–7
}}
* {{cite web
|url=http://infoserve.sandia.gov/cgi-bin/techlib/access-control.pl/1997/970443.pdf
|title=Cost Analysis of Energy Storage Systems for Electric Utility Applications
|month=February |year=2007
|first=Abbas |last=Akhil
|coauthors=Swaminathan, Shiva; Sen, Rajat K.
|publisher=Sandia National laboratories |format=pdf
}}
* {{cite web
|first=David |last=Larbalestier
|coauthors=Blaugher, Richard D.; Schwall, Robert E.;  Sokolowski, Robert S.; Suenaga, Masaki;  Willis, Jeffrey O.;
|url=http://www.wtec.org/loyola/scpa/04_02.htm
|title=Flywheels
|work=Power Applications of Superconductivity in Japan and Germany
|publisher=World Technology Evaluation Center
|year=1997 |month=September
}}
* {{cite journal
|title=A New Look at an Old Idea: The Electromechanical Battery
|url=http://www.llnl.gov/str/pdfs/04_96.2.pdf
|pages=12–19
|journal=Science & Technology Review
|month=April |year=1996
|publisher=[[Lawrence Livermore National Laboratory]]
}}
* {{cite web
|last=Janse van Rensburg
|first=P.J.
|title=Energy storage in composite flywheel rotors
|url=http://hdl.handle.net/10019.1/17864
|month=December |year=2011
|publisher=University of Stellenbosch, South Africa
}}
 
==External links==
*Ricardo Kinergy project http://www.greencarcongress.com/2009/11/kinergy-20091124.html
*Magnetal Whitepaper for its Green Energy Storage System - GESS http://www.magnetal.se/GESS.pdf
*Magnetal analysis on gyro forces induced by flywheel energy storage - http://www.magnetal.se/MagnetalGyro.pdf
 
{{Emerging technologies}}
 
{{DEFAULTSORT:Flywheel energy storage}}
[[Category:Energy storage]]
 
[[bg:Съхранение на енергия чрез използване на маховик]]
[[ca:Bateria inercial]]
[[de:Schwungradspeicherung]]
[[es:Batería inercial]]
[[it:Volano (batteria)]]
[[ja:フライホイール・バッテリー]]
[[pl:Akumulator energii kinetycznej]]
[[ru:Супермаховик]]

Revision as of 00:49, 18 August 2014


This page provides supplementary chemical data on Chlorobenzene.

Material Safety Data Sheet

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions. An external MSDS is available here.

Structure and properties

Structure and properties
Index of refraction, nD 1.5241
Abbe number ?
Dielectric constant, εr 5.6895 at 293.2 K
Bond strength ?
Bond length ?
Bond angle ?
Magnetic susceptibility, χm 69.5 x10-6 cm3 mol-1
Surface tension, 34.78 dyn/cm at 10°C
32.99 dyn/cm at 25°C
30.02 dyn/cm at 50°C
27.04 dyn/cm at 75°C
24.06 dyn/cm at 100°C
Speed of Sound 1311 m/s at 20°C

Thermodynamic properties

Phase behavior
Triple point ? K (? °C), ? Pa
Critical point 633.4 K (360.25°C), 4.52 MPa
Std enthalpy change
of fusion, ΔfusHo 		? kJ/mol
Std entropy change
of fusion, ΔfusSo 		9.6 J/(mol·K)
Std enthalpy change
of vaporization, ΔvapHo 		40.97 kJ/mol
Std entropy change
of vaporization, ΔvapSo 		? J/(mol·K)
Solid properties
Std enthalpy change
of formation, ΔfHosolid 		? kJ/mol
Standard molar entropy,
Sosolid 		? J/(mol K)
Specific heat capacity, cp ? J/(mol K)
Liquid properties
Std enthalpy change
of formation, ΔfHoliquid 		11.1 kJ/mol
Standard molar entropy,
Soliquid 		? J/(mol K)
Specific heat capacity, cp 150.1 J/(mol K)
Gas properties
Std enthalpy change
of formation, ΔfHogas 		52.0 kJ/mol
Standard molar entropy,
Sogas 		? J/(mol K)
Specific heat capacity, cp ? J/(mol K)
Van der Waals' constants a = 25.8 L2bar/mol2
b = 0.1454 L/mol
Other properties
Std molar enthalpy of hydration of gas,
ΔhydH∞ = ΔsolH∞ - ΔvapHo 		-30.6 kJ/mol @ 298.15K

Vapor pressure of liquid

P in Pa 10 100 1k 10k 100k
T in °C -43 e -17 e 16.8 62.9 131.3

e - extrapolated data

Viscosity of liquid

T in °C -25 0 25 50 75 100
Viscosity in mPa s 1.703 1.058 0.753 0.575 0.456 0.369

Thermal Conductivity of liquid

T in °C -25 0 25 50 75 100
Conductivity in W/m K 0.137 0.132 0.127 0.123 0.118 0.113


Spectral data

UV-Vis
λmax ? nm
Extinction coefficient, ε ?
IR
Major absorption bands ? cm−1
NMR
Proton NMR  
Carbon-13 NMR  
Other NMR data  
MS
Masses of
main fragments 		 

References


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