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Stirling Engines Presented by Josue De Lara Bashulto D.G. Thombare, S.K. Verma, Technological development in the Stirling cycle engines, Renewable and Sustainable Energy Reviews, Volume 12, Issue 1, January 2008, Pages 1-38

Stirling Engines

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Stirling EnginesPresented by Josue De Lara BashultoD.G. Thombare, S.K. Verma, Technological development in the Stirling cycle engines, Renewable and Sustainable Energy Reviews, Volume 12, Issue 1, January 2008, Pages 1-38OutlineIntroductionComponents of a Stirling engineThermodynamics of Stirling cycle engineEngine configurationWorking fluids for Stirling enginesAdvantagesDisadvantagesProspective applicationsConclusions2IntroductionRobert Stirling, minister of the Church of Scotland, 1816Reliable, reasonably efficient, and safe vs. reciprocating steam enginesMostly small enginesPump waterMarine engine (300 b.h.p.)By 1914, commercial production had stopped entirely Gasoline and oil enginesElectric enginePhilips research (beginning 1938)3Stirling Engine componentsPISTONExpansion spaceCompression spaceREGENERATORHEATERCOOLER4Stirling CycleThermodynamics5Thermodynamics of Stirling engineThe first and second law of Thermodynamics apply to all engines, including Stirling1st Law: The work can never be greater than the supplied heatFURTHER2nd Law: It must always be lessThermal efficiency

Carnot efficiency

6Thermodynamic Stirling cycle1-2; Isothermal expansion

HOTCOLDPVTS12127Thermodynamic Stirling cycle2-3; Isochoric heat removal

HOTCOLDPV12TS12338Thermodynamic Stirling cycle3-4; Isothermal compression

HOTCOLDPV12TS1233449Thermodynamic Stirling cycle4-1; Isochoric heat addition

HOTCOLDPV12TS12434310Stirling EngineConfigurations11-Engine configurationSimplest Stirling engine configurationTwo pistons in separate cylindersConnected in series by a heater, regenerator and coolerBoth pistons need seals to contain the working gasCan be extended to multi-cylinder configurationExtremely high specific power outputIdeal for automotive applications

Image credit: Zaphiris (2007) used under GNU License12-Engine configurationDisplacer-piston arrangementPiston: gas-tight fluid sealWork done on/or the gas by the pistonDisplacer: same pressure on either sideNo work done on/or by gasCrankshaft used to maintain phasePhilips primary configuration research

Image credit: Zaphiris (2007) used under GNU License13-Engine configurationSimilar to , -engines use piston-displacerEach on a different cylinderConvenient separation between heat exchangersLarger dead volumeReduced specific powerSome expansion must take place in the compression space

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Separate cylindersSpecific powerWorking fluids for Sterling engineMany fluids with high specific heat are suitableDesirable properties are:High thermal conductivityHigh specific heat capacityLow viscosityLow densityCapability factor:Working fluidHeat transferCapability factorAir11Helium1.420.83Hydrogen3.420.68Water1.950.39SodiumPotassium eutectic32.621.32

15Advantages of Stirling enginesNo noise or vibrationMultiple fuelsMultiple heat supplies: thermal energy from combustion, electrical, concentrated solar energy, radioisotope and nuclear reactor heatAdvanced engines are superior to petrol enginesAble to match diesel engine part-load economyHighest thermal efficiency for thermal-energy conversion deviceExcellent part load torqueCombustion products are not in contact with moving parts long life and low maintenance16Disadvanteges of Stirling enginesAdvanced engines are costly and complexSimpler versions are less costly, but with diminished efficiency and specific outputMaterials and designHeating: Tmax, materials,pressure and leakageCooling: handle more heat/h.p. efficientlySeals: leakage and cost of fluid (not air)17Prospective applicationsAutomotive engines (Celebrity MOD II)Cryogenic cooling enginesRefrigerating machinesSmall-electric power generatorsMarine engines (The Ericsson)Underwater power systems (Kockums AIP)Solar-powered engines (DOE, SES, PSA)Nuclear-reactor base load electric generatorsTotal-energy systems18Stirling Energy SystemsSolar One: Mojave Desert500-850 MW; 20,000-34,000 solar dishesSolar Two: Imperial Valley, CA300-900 MW; 12,000-36,000 solar dishes

19ConclusionsProven Stirling Cycle EngineMultifuel: liquid, gaseous, solid, using ample T rangeEq. Solar radiation, industrial waste heat, agricultural waste hear (biomass), and many otherComplicated thermo-mechanical designAdvanced materialsWorking fluidMost of the research made by PhilipsRenewed interestDouble acting, low T, -configuration, solar powered is currently the most attractive option

20ReferencesD.G. Thombare, S.K. Verma, Technological development in the Stirling cycle engines, Renewable and Sustainable Energy Reviews, Volume 12, Issue 1, January 2008, Pages 1-38

"HowStuffWorks "How Stirling Engines Work"" HowStuffWorks - Learn How Everything Works! 08 Apr. 2009 http://www.howstuffworks.com/stirling-engine.htm

"Plataforma Solar de Almeria." Plataforma Solar de Almeria. 08 Apr. 2009 http://www.psa.es/webesp/index.html

"Stirling Engine." Stirling engine. Wikipedia. 8 Apr. 2009 http://en.wikipedia.org/wiki/Stirling_engine

SES Stirling Energy Systems. 08 Apr. 2009 http://www.stirlingenergy.com/

Walker, G. Stirling-cycle machines. Oxford: Oxford UP, 197321