[PDF] Ocean Thermal Energy Conversion (OTEC)

Because an OTEC plant is an extensive, expensive infrastructure to build for the benefit of everyone, the geographical adaptation of the technology is much more

To an engineer this implies that there are two enormous reservoirs providing the heat source and the heat sink required for a heat engine A practical application is

[PDF] Ocean Thermal Energy Technology Brief - International Renewable

» Process and Technology Status – Ocean Thermal Energy Conversion (OTEC) technologies use the temperature difference between warm seawater at the

State of the Technology OTEC power systems operate as cyclic heat engines They receive thermal energy through heat transfer from surface sea water

[PDF] Ocean Thermal Energy Conversion: An Overview - NREL

an open-cycle ocean thermal energy convers ion system on WindlOcean Technologies Dtvtslon Figure 4 Mini~OTEC off Keabote Point Howatt (Courtesy of

[PDF] Ocean Thermal Energy Conversion (OTEC) Technology

Ocean Thermal Energy Conversion (OTEC) is a technology for generating renewable energy that uses the temperature differential between the deep cold and

[PDF] OCEAN THERMAL ENERGY CONVERSION AND THE PACIFIC

provide technical information on “New Energy Technologies”, in particular, hydrogen fuel, ocean thermal energy conversion (OTEC) and space solar power

[PDF] Ocean Thermal Energy Conversion - National Institute of Ocean

There are technological hurdles to overcome to tap the immense potential of OTEC But still the technology is mature enough to establish commercial power plants

[PDF] Ocean Thermal Energy Conversion (OTEC) - OAPEN

Because an OTEC plant is an extensive, expensive infrastructure to build for the benefit of everyone, the geographical adaptation of the technology is much more

[PDF] la techtonique des plaques

[PDF] La tectonique des plaque !

[PDF] la tectonique des plaques

[PDF] La tectonique des plaques

[PDF] la tectonique des plaques 1ere s

[PDF] la tectonique des plaques 4eme

[PDF] la tectonique des plaques cours

[PDF] la tectonique des plaques cours pdf

[PDF] la tectonique des plaques l'histoire d'un modèle controle

[PDF] la tectonique des plaques svt 3eme pdf

[PDF] La tectonique des plaques SVT SVP AIDER MOI !

[PDF] La télé réalité humilie t-elle les candidats / La télévision est-elle un moyen de se cultiver

[PDF] la télécabine DM math

[PDF] la télémétrie laser et la lune exercice corrigé

[PDF] La télévision en couleur

BOOKCITATIONINDEX

C L A R IV A

TE ANA

L Y T IC S IN DEXED 4 Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

4 Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

interconnected geoscience phrase

Interconnected geoscience

alone. 7 Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

interconnected geoscience phrase

Interconnected geoscience

alone. 7 Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

4. PacificIslands geographyand geology

Figure 2

Figure 2.

GeographyofthePa cifi cIslan dsregion.Noteth earchipelagona tureofmostPSIDS withisla ndsscat teredover

largearea sofocean.AS ,A mericanSamo a;AU,Au stralia;CI,CookIs lands;FM,Fe deratedSt atesofMicronesia;

FJ,Fi ji;PF,Fre nchPoly nesia;GU,Guam; KI,Kiribati;MH,Ma rshall Islands;NR, Nauru;NC ,New Caledonia;NU,Niue; NZ,New Zealand;MP, Marianas Islands ;PG,PNG;PN,P itcairn; PW,Palau;WS, Samoa;SB, Solomon Islands;TK,Toke lau;TO,Tonga;TV, Tuvalu;VU,Vanuatu ;WF,WallisandFutun a. Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

4. PacificIslands geographyand geology

Figure 2

Figure 2.

GeographyofthePa cifi cIslan dsregion.Noteth earchipelagona tureofmostPSIDS withisla ndsscat teredover

largearea sofocean.AS ,A mericanSamo a;AU,Au stralia;CI,CookIs lands;FM,Fe deratedSt atesofMicronesia;

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 3.

Figure 4.

Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 3.

Figure 4.

Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

13 13 Summary ofthe developmentand energycontext ofKiribati (UN[16], WorldBank [20],NZMFAT [21],

United Nations[22]) .

Many atollPSIDS havedeveloped high-densityconcentration urbancentres whichattract populationsfrom the

outer islands.These islandsare characterisedby highdensities ofhousing, manyof whichare traditionalhouses

and someof lower-qualityinformal style.Examples ofurbanised centresinclude Funafuti(Tuvalu), South Tarawa (Kiribati),and Ebeye/Majuro(Marshall Islands). Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Summary ofthe developmentand energycontext ofKiribati (UN[16], WorldBank [20],NZMFAT [21],

United Nations[22]) .

Many atollPSIDS havedeveloped high-densityconcentration urbancentres whichattract populationsfrom the

outer islands.These islandsare characterisedby highdensities ofhousing, manyof whichare traditionalhouses

and someof lower-qualityinformal style.Examples ofurbanised centresinclude Funafuti(Tuvalu), South Tarawa (Kiribati),and Ebeye/Majuro(Marshall Islands). Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Graph ofGDP/capita vs.electricity usageper capita.See textfor details[23]. Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Graph ofGDP/capita vs.electricity usageper capita.See textfor details[23]. Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Installed electricitygeneration forselected PacificIsland countries(data, UnitedNations [22]). Notethe

logarithmic scaleon theY-axis.

Graph ofinstalled electricitycapacity perhead versusGDP/head forselected PacificIsland countries.Note how

Kiribati andSolomon Islandsare theleast energizedcountries andFiji/Marshall Islandsthe mostenergized from thisanalysis. Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Global mapof OTECactivities andresource interms ofthe temperaturedifference betweensurface seawater and seawaterat adepth of1 km.The highesttemperatures (andhighest potentialOTEC energyresources) are situated NEand Eof PapuaNew Guinea,Indonesia, andthe Philippines.Significant thermalresources are present withintropical andsubtropical watersin alloceans andcan benefitSIDS andcontinental countries

within thisarea. Kiribatiand itscapital townshipof SouthTarawa liewithin the'bulls eye'of thermalenergy

resources. Aminimum temperaturedifference of17 °C betweensurface watersand watersat 1km depthare required forOTEC atthe presenttime (acknowledgementsKRISO) . Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Installed electricitygeneration forselected PacificIsland countries(data, UnitedNations [22]). Notethe

logarithmic scaleon theY-axis.

Graph ofinstalled electricitycapacity perhead versusGDP/head forselected PacificIsland countries.Note how

within thisarea. Kiribatiand itscapital townshipof SouthTarawa liewithin the'bulls eye'of thermalenergy

DOI: http://dx.doi.org/10.5772/intechopen.91945

Principles ofOTEC. Aworking fluid(R32 withinclosed cycleOTEC plantsuch ason Kiribati)is vaporised, with thevapour turninga turbineto createelectricity. Thevapour iscooled fromdeeper seawaterand then heated viaheat exchangesto bevaporised oncemore. OTECplants canalso providedesalinated drinkingwater and watersfor agriculture/aquacultureat downstream(acknowledgements ScientificAmerican [25]). Temperature-entropy (heattransfer dividedby thetemperature) .Diagram ofan OTECcycle(after[5, 6]). Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress

Figure 14

ParameterValueUnit

Table 3.

Analysis resultof Rankinecycle OTECdemonstration plant. 21
Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 14

ParameterValueUnit

Table 3.

Analysis resultof Rankinecycle OTECdemonstration plant. 21
Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 17.

Operation sceneof barge-mounted1 MWOTEC plant(L) andmonitoring system(R) . Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 17.

Operation sceneof barge-mounted1 MWOTEC plant(L) andmonitoring system(R) . Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 18.

Figure 19.

Figure 18.

Figure 19.

Figure 22.

Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 22.

Can OceanThermal EnergyConversion andSeawater UtilisationAssist SmallIsland Developing...

DOI: http://dx.doi.org/10.5772/intechopen.91945

Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress e? hC ??he?he????h ahe?h??peI?h

?? C?hee?I

eI Chh C ????tIp?hh...It?C??hee?t??peI?t ?? C? ? ?It?C??? I?e?I eI ChpC h??? teI Cha ?hh

C Ct ????tIp?h? ???rh? I

he?h ?IICp?hI?h? ????htIe? h 52
52
c u

Schematic diagramof turbinepneumatic structure.

The wheeldiameter ratiorefers tothe ratioof impelleroutlet diameterto inlet diameter, andthe wheeldiameter ratiodetermines theturbine workingability, which isgenerally selectedbetween 0.35and 0.55.Degree ofreaction refersto the ratio ofthe isentropicenthalpy dropin impellerto thetotal isentropicenthalpy drop in turbine,which representsthe distributionof energywhen gasexpands innozzle and impeller.A largerdegree ofreaction meansa fastervelocity ofthe airflow discharged fromimpeller andmore residualvelocity loss.When thedegree of reaction istoo small,deceleration motionwill occur.For turbine,it isgenerally selected between0.3 and0.5. Thevelocity ratiois theratio ofcircular velocityat impeller inletto theideal velocityunder isentropiccondition, whichreflects the influence ofrotational speedon turbine,generally selectedbetween 0.5and 0.8. There aremany waysto determinethe thermodynamicparameters ofturbine, such astrial method,optimal velocityratio method,and screeningmethod. Thetrial method refersto thecalculating wheelefficiency usingselected parameterssuch as degree ofreaction, wheeldiameter ratio,velocity ratio,inlet nozzleflow angle,and impeller outletflow anglein orderto determinethe optimaldesign. Thismethod has greatblindness andrequires alot ofwork. Theoptimal velocityratio method determines themain designparameters suchas thevelocity ratioand thedegree of reaction byinterpretation method,such as"zero tailvortex "analysis methodand specific velocityanalysis method.The screeningmethod isused toanalyze the effect ofthe mainparameters suchas pressureratio, Machnumber, angleof attack, and allowablestress ofwheel indetermining turbinevelocity ratioand degreein detail. Thismethod hashigh efficiencyand canprevent largechanges. In thischapter, thedesign ofa turbineusing ammoniaas workingfluid for

7.5 kWOTEC isshown asan example.According tothe calculationresult ofcycle,

the giventhermodynamic designparameters ofturbine areshown inTable 1. In orderto obtain1-D designparameters, theimportant parametersto bedeter- mined includewheel diameterratio D 2 , degreeof reaction, velocityratio u 1 velocity coefficient,and bladeangle. Velocitycoefficient includesthose ofimpeller and nozzle. Bladeangle includesimpeller inletmounting angle 1 and nozzle outlet mountingangle 2 in [16].The valuesof theseseven basicparameters are selected bythe abovevarious methodsin properrange. Finally,the rangeand values of theseven basicparameters selectedare listedin Table 2. Basedon design parameters, thermodynamicparameters inturbine arecalculated and1-D thermo- dynamic designis completed.The resultis shownin Table 3. In theprocess of1-D designabove, theparameters aredetermined byusing traditional methods.There are,however, limitationsin themethods, suchas time-

Figure 3.

Velocity triangleof radialturbine impeller.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

c u

Schematic diagramof turbinepneumatic structure.

7.5 kWOTEC isshown asan example.According tothe calculationresult ofcycle,

Figure 3.

Velocity triangleof radialturbine impeller.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

u D u D D u u

The designparameters ofturbine.

D u

The rangeand valuesof thebasic parameters.

Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress

ParametersUnitsResults

Impeller speedr/min21,000

Nozzle outletvelocity m/s155

Nozzle outletpressure MPa0.802

Nozzle outlettemperature K291.08

Impeller inletheight mm5.8

Impeller inletabsolute flowangle °14

Impeller inletrelative flowangle °86

Impeller inletrelative velocitym/s37

Impeller inletdiameter mm120

Wheel peripheralspeed m/s156

Impeller outletabsolute flowangle °101.22

Impeller outletabsolute speedm/s49.16

Impeller outletrelative flowangle °35

Impeller outletexternal diametermm56.2

Impeller outletinner diametermm31.7

Power generationkW7.8

Efficiency ofthe wheelperiphery - 0.864

Table 3.

The resultof 1-Dthermodynamic design.

ParametersUnitsResults

Impeller speedr/min21,000

Nozzle outletvelocity m/s160.5

Nozzle outletpressure MPa0.785

Nozzle outlettemperature K290

Impeller inletheight mm4.398

Impeller inletabsolute flowangle °16

Impeller inletrelative flowangle °90

Impeller inletrelative velocitym/s40.9

Impeller inletdiameter mm126.8

Wheel peripheralspeed m/s159.4

Impeller outletabsolute flowangle °99.364

Impeller outletabsolute speedm/s49.16

Impeller outletrelative flowangle °35.745

Impeller outletexternal diametermm57

Impeller outletinner diametermm28.8

Power generationkW7.65

Isentropic efficiency - 0.875

Table 4.

The resultsof 1-Dthermodynamic optimization.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

u D u D D u u

The designparameters ofturbine.

D u

The rangeand valuesof thebasic parameters.

Ocean ThermalEnergy Conversion(OTEC) -Past, Present,and Progress

ParametersUnitsResults

Impeller speedr/min21,000

Nozzle outletvelocity m/s155

Nozzle outletpressure MPa0.802

Nozzle outlettemperature K291.08

Impeller inletheight mm5.8

Impeller inletabsolute flowangle °14

Impeller inletrelative flowangle °86

Impeller inletrelative velocitym/s37

Impeller inletdiameter mm120

Wheel peripheralspeed m/s156

Impeller outletabsolute flowangle °101.22

Impeller outletabsolute speedm/s49.16

Impeller outletrelative flowangle °35

Impeller outletexternal diametermm56.2

Impeller outletinner diametermm31.7

Power generationkW7.8

Efficiency ofthe wheelperiphery - 0.864

Table 3.

The resultof 1-Dthermodynamic design.

ParametersUnitsResults

Impeller speedr/min21,000

Nozzle outletvelocity m/s160.5

Nozzle outletpressure MPa0.785

Nozzle outlettemperature K290

Impeller inletheight mm4.398

Impeller inletabsolute flowangle °16

Impeller inletrelative flowangle °90

Impeller inletrelative velocitym/s40.9

Impeller inletdiameter mm126.8

Wheel peripheralspeed m/s159.4

Impeller outletabsolute flowangle °99.364

Impeller outletabsolute speedm/s49.16

Impeller outletrelative flowangle °35.745

Impeller outletexternal diametermm57

Impeller outletinner diametermm28.8

Power generationkW7.65

Isentropic efficiency - 0.875

Table 4.

The resultsof 1-Dthermodynamic optimization.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

ParametersUnitsValues

Figure 7.

Figure 8.

Figure 7.

Figure 8.

Table 6.

Figure 11.

Table 6.

Figure 11.

Figure 13.

Figure 17.

Figure 18.

Optimized streamlinediagram ofnozzle andimpeller at50% spanwise. Static pressurecurve at50% spanwiseof impellersurface.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

Figure 17.

Figure 18.

Optimized streamlinediagram ofnozzle andimpeller at50% spanwise. Static pressurecurve at50% spanwiseof impellersurface.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

seal flowchannel systemfrom externalsystem atthe shaftduring thehigh-speed rotation ofshafting. Theyhave variousstructural forms,which willbe introduced in detailin thenext part.The staticsealing componentis mainlyan O-ringthat contacts thestationary componentsto isolatethe workingfluid, lubricatingoil, and outside air.If high-speedgenerators areused forpower generation,it canbe driven by turbo-sideshafting togenerate electricityat ahigh speedand thenconverted into 50/60Hz conventionalpower byrectification inversion.While thecontrol part mainly controlsturbine steamvolume, speed,and generatoroperation, italso includes digitalcontrol systemwith emergencyinterruption, whichwill be described inthe nextsection. shows theschematic diagramof turbine.Mechanical sealis usedfor turbine inthis case,and ahigh-speed generatoris usedfor powergeneration. Therefore, theshafting systemmainly includesthe mainshaft, high-speedbearing, and high-speedcoupling. Themain shaftis animportant componentconnecting impeller andhigh-speed motor,which transfersthe workof impellerto ahigh- speed coupling.There aretwo high-speedbearings, whichplay asupporting rolein the mainshaft rotatingprocess andensure thatthe shaftdoes notmove inthe circumferential andaxial directionwhen rotatingat ahigh speed.The high-speed coupling connectsthe mainshaft andhigh-speed generatorto ensurethat thework of themain shaftcan besmoothly transmittedto ahigh-speed generator.Oil circuit seal flowchannel systemfrom externalsystem atthe shaftduring thehigh-speed rotation ofshafting. Theyhave variousstructural forms,which willbe introduced in detailin thenext part.The staticsealing componentis mainlyan O-ringthat contacts thestationary componentsto isolatethe workingfluid, lubricatingoil, and outside air.If high-speedgenerators areused forpower generation,it canbe driven by turbo-sideshafting togenerate electricityat ahigh speedand thenconvertedquotesdbs_dbs46.pdfusesText_46

[PDF] [PDF] Ocean Thermal Energy Conversion (OTEC) - OAPEN

BOOKCITATIONINDEX

TE ANA

DOI: http://dx.doi.org/10.5772/intechopen.91945

DOI: http://dx.doi.org/10.5772/intechopen.91945

Interconnected geoscience

DOI: http://dx.doi.org/10.5772/intechopen.91945

Interconnected geoscience

DOI: http://dx.doi.org/10.5772/intechopen.91945

4. PacificIslands geographyand geology

Figure 2

Figure 2.

DOI: http://dx.doi.org/10.5772/intechopen.91945

4. PacificIslands geographyand geology

Figure 2

Figure 2.

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 3.

Figure 4.

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 3.

Figure 4.

DOI: http://dx.doi.org/10.5772/intechopen.91945

United Nations[22]) .

United Nations[22]) .

DOI: http://dx.doi.org/10.5772/intechopen.91945

DOI: http://dx.doi.org/10.5772/intechopen.91945

DOI: http://dx.doi.org/10.5772/intechopen.91945

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 14

ParameterValueUnit

Table 3.

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 14

ParameterValueUnit

Table 3.

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 17.

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 17.

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 18.

Figure 19.

Figure 18.

Figure 19.

Figure 22.

DOI: http://dx.doi.org/10.5772/intechopen.91945

Figure 22.

DOI: http://dx.doi.org/10.5772/intechopen.91945

 ?? C?hee?I

C Ct ????tIp?h? ???rh? I

Schematic diagramof turbinepneumatic structure.

7.5 kWOTEC isshown asan example.According tothe calculationresult ofcycle,

Figure 3.

Velocity triangleof radialturbine impeller.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

Schematic diagramof turbinepneumatic structure.

7.5 kWOTEC isshown asan example.According tothe calculationresult ofcycle,

Figure 3.

Velocity triangleof radialturbine impeller.

Current Developmentand Prospectof Turbinein OTEC

DOI: http://dx.doi.org/10.5772/intechopen.90608

The designparameters ofturbine.

The rangeand valuesof thebasic parameters.

ParametersUnitsResults

Impeller speedr/min21,000

Nozzle outletvelocity m/s155

Nozzle outletpressure MPa0.802

Nozzle outlettemperature K291.08

Impeller inletheight mm5.8

Impeller inletabsolute flowangle °14

Impeller inletrelative flowangle °86

Impeller inletrelative velocitym/s37

Impeller inletdiameter mm120

Wheel peripheralspeed m/s156

Impeller outletabsolute flowangle °101.22

Impeller outletabsolute speedm/s49.16

Impeller outletrelative flowangle °35

Impeller outletexternal diametermm56.2

?? C?hee?I

C Ct ????tIp?h? ???rh? I