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On the cover: Photo on left····",verUcaJ.,spout evaporator developed toran open -cycle ocean thermal energy convers ion system. on
top to boHorn"'········hoat,· and mass-transfer test apparatus,turbine rotor , for the direct -contact condenser. and a sectionalview of a heat fJ;JXICt11!1n(ler
OceanThermalEnergyConversion
An Overview
SERI/SP ~220 ·»3024
November1989DE89000838
UC Category: 262
Preface
Ocean thermal energythermal This ·f' i':x(·~ t''l t"lr·'k l:f'''t l''·i''\.i
();·.rE:(: research is funded the l ....f.S, .li·.·:" ·... ·· · ~.·.t U .l- l ·*..t.l-"'-d ·J.t.· Theto the tee .•nnotosv assessment of its
J)ot:eutJ.ttl··'·'·'·'·'·'·'·'·:(~·lttH>r asanalternativeor asasupplementto convenuonatenerzv sources. funded researchto and will ()~·I ·<l.:S(.: to the threshold of commercial ization. This ououcauonrlrf)V 1 th(~ , all ()verv iewof the (:rI;.E~(: f '/.·:. ;:··, ·h, ..·\ ;:"". 1 ;..,'>, '
Produced for theWindlOcean Technologies Dtvtslon
u~s~ Department of Energy4iiiiiiii»iiiiiiii 'Ilell
Solar Energy Research InstituteA Division of Midwest Research Institute
A Productof theSolar TechnicalInformation Program
1617CoteBou levardGolden, CO 80401 ~3393
Operated for theU~S~ Department of Energy
Noticeoreoarec as an account of work an the United Statos governrnont Noither the United States ccvernmem
Morany of thoir makesany warranties; expressor orassomes any or re~H)(lns,ltHhlV
comoeteness. or usofulnOS$ of any inforrnatioM; apparatus; or processcisclosed. or represents that Hs usewould notReference name,trademark, manufacturer.
necessarnv constitute or recommencano». or the States oranyagoncy thoroot Thoof authors stateor rofloctthose 01 tht) UnitodStates or any agoncytheroof,
National Technical ~nforrntttion Sen/icoUJ3. of Commerce
Road22161
Prict); Microfiche A01Printed AOS
Cooes are used forcodes can bofoundGovemmeotavailablekorn
all Put)liC;atJc~ns.
thecurrentissue onne lOHO\NHld PubltCtJtlc>nsAnnouncernonts and Inat):x
at: tho abOVE; address.
tho numberof pagosin tho!ntorrnanoo nblrh~jnit"'1~N
an) ceneranv aVtlll;aOIH in roost liorades:Tectmice! Abstract
Contents
Introduction . .'\lhnt ()'·.fE(.:?.
of orsc'Ihe Federal I·'rc\n·t~~:llr'r)
ChapterI-c-Power Cycles"'..' ,',." ,.~ "'-.' orsc·'- .." e. n ". "' , orsc
()f'l··I.:.~(: S vstems
EnhancedCurrent Activities in Power
Ch,..pt.er2-1)lan.tl)e~:ig'1 and LocatlonLand-Based and Near-Shore FacilitiesShelf-MountedFacitiries ., . .' . . . <
I··"f,{"\{il':if"i Ct' FacilitiesPowerPlants
Current Activities in c:rrE:(::
Chapter :;-]~lleSeaW'~I.t:erSystem::slH;l)e:n(l(;~(1 Seawater '\.f cr t~llH';:
Bottom-Mounted Seawaterxvstems
Chapter 4-(:;(llnplelnellt.Ur}l()]'~F:,(~:I·lr(:)(luctsDesalinatedWater ., ... < •••
ater-Supoortec Mariculture
Chapter 5-F;nV'it~(ln.ll1entallss·ues
Marine InteractionsAnrommz Coastline Interactions ., . . . <
ArmosnnencInteractions ., < ,
Current Activities in Environmental Assessment
Chapter 6-!rhef\utureof ()"r:E:(::
References ., . . . . . ., . . . . .,
Appendlx-s-Particlpants in the l)()E: Ocean EnergyTechnologyProgram (1987-1989) '<"""""" ." , .,
iii
• I.I
.5
.6
.9ioI()
131314141516
17171818202()
21
22
23
2525262627
29
Figure 4 Mini~OTEC off Keabote Point Howatt (Courtesy ofthe Lockheed Missiles and Space Co,}
Introduction 3
Chapter 1
Power Cycles
Closed-Cycle OTEC
/"·.·,·...~·'\;:··.,,,::~:t'''''t'~·< \Xic:re andi980s. 12 R.escarch.on
Warmwater in
Discharge waterto sea
Evaporator
Discharge waterto sea
Working fluid
Workingfluid
vapor
Workingfluidpressurizer
(boner feedpump)
Wortdngfluid
V8,por
Workingf:luidconoensate
tCondenser
tCold
water in
PowerCycles 5
a. Horizontal shell and tube
Ammonia in
Wateroutt
Ammonia out
Waterout ...-,
Seawatere. Plate and fin
,.#'.~..,"
·1ftAmmonia liquid
Ammonia
e. Vertical shell and tube
d~ Plate and frame
Open-Cycle OTEC
Warmseawater in
Daaeralion(optional)
III,
Noncondensablegas-es
Noncondensablegases
tVacuum chamber
flashevaporator
Warmseawaterdischargeto sea
Desalinatedwatervapor
(unsaturated)
Des-alinatedwatervapor
{saturated}
Cold seawaterdischarge
to sea
tCondenser
tCold
seawaterin
Desalinated- - .... water
(optional)
FI}'Jure 1,3 An open-cvcle OTEC system
PowerCycles 7
Enhanced OTEC Systems
10 Ocean Thermal Energy Conversion: An Overview
Current Activities in Power Cycles
Figure 1,9 Heat exchanger test facility at Argonne National Laboratory (Courtesy of ANL)
Power Cycles 11
Chapter 2
Plant Design and Location
Land-Based and Near-ShoreFacilities
Figure 2.1 The land-based 100~kWe (:gr058) OTEe plant atNauru (Courtesy of Tokyo Electric Power CO+ 1 Inc)
Plant Design and location 13
Bottom-Mounted Seawater Systems
Figure 3,2 Deplayrnent of the i -rn cote-water pipe at theNatural Energy Laboratory of Hawai~ (counesv of R,A4, TowillCorporation)
18 Ocean Thermal Energy Conversion: An Overview
Discharge Pipe
Chapter 4
Complementary OTEC Products
Desalinated Water
make svsiems attractive to andmuniueseven if the of oil remains10\\\ Someor()(IUC1S and QI::;~l·lnf."'*{:"·Q that could lje from
shown in
an ()··r~r.:(:: nroauce valuablecornptementary nffHlu.cts such oesannateo water
lion to ge:nt\~ratlung Jj()\VCC Thecold seawater be usedfor marinelife and for rerneersnon andconrnuonmg. These notenrrauv svneratsnc nell V11fl{*%
Norl
orec
Sun
Building
4,1 A
i% ·,\;:!j~''\>::'''·t·'·tt··'l''''~''{:'''·t·~·l·(·' continue at where the cold-seawater for research in both (rr[S(:':
tecrmoioav and its associated Additional waterf)Yt'Y\/1Iflt~'f1 at the Hawaii Ocean Scienceand 'Iechnol-
aeracent to to in "··l.<'::"\·!'ii::*:I<"··"I<t~L.
Df()(1UCIS and markets associated with cold seawater. fJ\VOcommercial rnariculture veutures are under way therc.undothers are in the of Ocean Farmsof Hawaii uses cold seawater to grow ofnrennum abalone each year. Anothercompany,uses warm seawater to culture several of nucroaieaethat are sold as food supruemems, unarmaceun-
and food /';'j;"'> !ij('>:l"'j:'f'~ f'l"
Current Activities in ComplementaryProducts
Refrigeration and Air-Conditioning
·{·'~'t'''\;.A''t'','::~1'''tl'·'I<Y'l<.~< related or
·M,~,.,~ ~,,~..~ "/~ -l'''''''''~ trout t
waters, butLil.,.. -oumceo water to extend
nronncts available in thosemarkets.rerngen.:UJCHl available frcmcold
seawater can be used to or maintain the ofthe which tend to deteriorate in thewarm were conductedsuccesstunvon fruits and asso"ciated vlith mcderateclimatea such as lettuce and straw-berries. are grown in cooled and ·~t"'t'··lif'h:~'!·{:"',,·'l
a the fresh water thatcondenses on theexternal surfaces of the coild-water
can be used Other small are carried nut on a rrazmenteobasis around the world to evaluate specialnon-powerf.,,~·t"~···"1<';··~i·i'ti<···'·f.·t·'~.f·t' {·l<·y"'\·il'.".I·U···'·.·'l'···t.....\t··,~,·, for cold seawater. Theseefforts arenot tied to (y'I"EC': commercian..zanon: h~(·\·ltff,~·\/t'~r
rnay offer the; to generate 't'~"':j"f 1 r"t·,s'''''.I.'':'' 't·'ij;·t";(·'\.(··l:li'i""t'·i':'
supptementar incomefrom an ()'I~E::(:
annncanons until ()"''['E:(:::systerl1s can deliver andwater to island markets at comoenuve
ComplementaryOTECProducts 23
Chapter 5
Environmental Issues
The construction of land-based or shelf-mounted ()'l<·[~(.:
can disturb the sea bed. of t'y'\,..·\... ·"'~t'r·'\<·'t'·.:'<
and anchors may churn up the bottomand increase thenumber of in the water.This of disturbance can affect areas of
such as coral seagrass
of the effects shown in 5.1 are;:::~'I..>··t·'''';::'~;··'*·;:::~.;··1 from an ()v'rE~C~ 41C:onstn.lction activities may
the sea habitats anddecreasmz subsurface Platforms and marine sub-
rnay attract fish and other marine auemptsto reduce may increase the level of toxic sub",stances. Intake can draw marine the
and move amounts ofnutricnr-rich water up fromthe However, ()'·fI.:(:: can be and h)··cared to minimize their effects on the environment.
Like any offshore or shoreline commercial ('YI"E(::facilities will affect the marine environment.
Marine Ecosystem Interactions
The I)()E Ofi'I'Prouram has funded research to ouruneerstanoma of ()(]"'T::(::: interactions with marine eco-sysrems. and the and to
"·~·.'·'···>".".e·.·'·""""'··'.,· ....n.1 to lessenany adverse interne-tions, These studieshave UflCOVCre(1 1'10 insurrnountableenvironmentalobstacles to (YI<'r:;~(~ in cur-rent evidence thatmost environmental effects willbe minimal with those associated with conven-tional power Careful and strict
~..l*.~",f",/""..1U.%..~.l·\w,"~.. and well ~trained t·'\·;%·lf··';':·';t\*·'·*··l,::·:~ I
(y]'·'·E:<:.::: systems that are environmentaII y O ......·,y,··\...··l·.·n.(.M;...ta.~,:
ofpower,
+ Attraction
• Withdrawal of nutrient..richdeep waters
• Redistribution of nutrients
• Chlorinereleases (negligiblewith open-cycle operation)
• Trace metalsreleases
• Hull coating releases
• Temperature and pressurestresses
'<-:-~)«
Bottom scouring
1200
1300
1100
g15 700io 800
900
500
400
1400"-------------------------------~~-~-~~~
300
600
o.~~--~:.:~~--"""".._~~...,.,,........ ,
100
200
1000
Environmental Issues 25
26 Ocean Thermal EnergyConversion: An Overview
Adjoining Coastline Interactions
Atmospheric Interactions
immeruate releases canbe avoided conmtetctvany absorbed gas into the seawater i"tl~"{"!"1f*'i'~,f;I'f':~
that below the mixedcomnmma thesemethods.
Current Activities in EnvironmentalAssessmentThe of the variousstate, and federal with atNI:~[J""1 call forall environmental monitoring program that will help
resources in the Keahole J'>oint area, To evaluateHl:n~u ",1!t"":rI'n effectson the results of the monitor-
be with H. baseline of andoffshore water and offshore biota that: is estab-lished at·N.E.I...>lI.'rhe(lE~r IS a stateeffort that consists archival data and conecnnzsite: data to establish benchmark conditions at Keahole Point,which is to be the areafor (Jrl.:~(: in thenear The program is also technical andfiscal for the environmental at thesue.
Environmenta' Issues
Chapter 6
The Future of OTEC
of desalinated water at: the: S'rl~' (rrt::t(: tech-has stimulatedconsiderable interest in the process.
ongOJ:ng [)()I:t programis tocodes while
expenmentauv oemonstranna the technical. ofelectric power in anshownin
The J)()l:~ ()1.:1"r has prove11 the of closed-andhas it to the threshold of commer-
the program continues to advance."" ",.'t ,..".•:. research in. surface CCHluc:nSt)fS
tbio-
'J.·;J·W:·~,~·~·'~,l""'t corrosion. and (tr"E(; Thethis research mayallow '~l)l:ti'*i;;;'l':l"\}
engmeer the 2·»»15MW~:; envisioned forcal island markets, In addition. the recentvfirst" nrocucuon
Steam i~~~ __
Evaporators --~~11
To vacuumexhaust system
The Future of OTEe 29
References
1. d'Arsonval. A; "Utilization des forces naturelles,i\venir de I'electricire.~~ Revue \/oLI7 ~ :1881":Pl'. 37[)"m372,
16. Bharathan, n.,and ~I·. Penney, "Flash Evaporation fromTurbulent Water Jets," AS:\:tE' Journal ofHeat Transfer,vot 106" pp,4()7-m 4 15,
7. Shclpuk.B; a/\. i65~kWOpen ornement," presented at the 12th Annual Intersociety( N. ,. ·It·, > ,. '1'· .> , 1) 1 'It"1
.c-:·onve:nnon i::~ngHleenng l,l Jarnl l)eacll~ f< ..., •
August 1985;also SER.lrrF',~251 ~2725.~ Golden, C:+().
References 31
Devetomnenr Corporation, Hawaiianecnnotovv Park and Natural
/){)!llP.rllfl\'f} Environmental Monitor-nrenareo tor the st.ate of 1....Iawaii, unpublisned
35.
36. Krutzcn. \VJ:::':+~ "'./\ Stare-ot-the-An Look at.orscPumping lIth Annualshore 3~t·1 .. .. ~.]N'X7t .... ouston, .. r .•
32
of
4,7, from the Oceans: A SmallLand-BasedOcean ThermalE'E·Z Resources TechnoloevAssessment. tlOO().lU11U." ,.., , •. +
1988.
46, 1..Jno". T etStudies fete (Y·fl:.:(:: Plantsxenunuc cfshore Mechanicsand Arctic tinotneermv
NewYork: Americanpp.618·N625,
of
tjtJen:tne~r,"Carbon Dioxidenresenteu at the
t:I1.. 2Jli·IC(:~rs lntcrnational Con '"
Mechanics and Arctic ".....~, '.?''', ". '··',.··V'
13-·",vI8~Ne\\/ York: '"['he AmericanMechanical l pp. 585·····592,
AppendixParticipants in the DOE Ocean Energy
Technology Program (1987-1989)
Oceanit i.aoorarorv Inc.
Pacific International Center for
EJv1+Rivera andSons
Florida Solar Center
Solar
l·lawaii Natural Institute State of Hawaii
Inc.
Makai Ocean nnsmeenne
Texas i\.(fStr.vl ',..f' ~ +.+ d·'.> ..
t.in iversi tv of Delaware
Massachusetts Institute of
Inc.
Natural l..All)OJCah)fV of Hawaii
Appendix 35
Information on the lJ,Sx ucoartrnem Ocean contact:
Headquarters
Dr.Robert L, San MartinAssistant for Renewable
586~9275
Mr. I...ouis V Direc torOffice of Solar Electric 1e(:.nJI01(Jg)(~S
586,.,. 554()
Director'i::'h"" li"'<'f'~"'>t ~ •. ,'1<n'·~·>::·~c Ilivision
Dr.Rc Gerakl 1...eaderSolar Eneruv Research Institute1617 <::":oleBoule'lard
...,....~~,..~.l,&.,t"'··),· *.. C::() 8()4() l231,·,·,1758
.<.,.~ • "." .....ax ..... NationalLaboratories9700 South AvenueK :J....f. y...,.~,..f.l. t:J~."".· t Il.:~60439
12) 972~·823()
lJ~S*I)epart:nlt~td: ef'EnergyForrestal l::S HItOI.n,}!
1()()O S\Vwasmnston, 1)(: 20585
Conservation andRenewableJ:>,(), Box 890()Silver rvtl) 209()7
523--2929462 ...4983 {f·.1ptt·1n,t'\fll\/ >':~ln'~ ~l
233--3(J71
36
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se~\·\s
'\ :,•.......r ·t:~ n· . · ero' ·~. ' liesearcbInstitu.tC)."oa p t')o .. • . ..
",.r"'.)' p' '.\{ ') .l''\ [ l.·.·.~.·. l:.l..l ..CMidwest Rese:arch
IUbu
wtC
r- l 'i·.\'\i J.5 ·· ·· l~ ' itt \
16\1 ColcBt)U\Cvard
(Jo\d.en.~ (:()
r)......... i". ij., <:\" {';{' {ortheU.S. 1)eparttnent of l!,nerg)'