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Unformatted text preview: WTGERS. MAE 14:6502474 Alternative Energy Systems School of Engmeenn Quiz 2 (please print) Total Score: Page 2 of 1D
' Mtlltiplo' Choice (4 points each) Figure 1 dopiots on omoyole ooear. ﬂ'tormal enorgy oomorsion (DIED) system. Use Figure l 1):: answer
questions 1—4. VﬁWUi‘ﬁ Pumn LOWPIGSSUT'E 5163M
 Gonoramr
3
Direobco ntatt
condo war
4 Dissoiuod
Gases Warm51.1 rfaoe
Water “tam—Water
Discharge Coldwatar Bald BEEF
Disch argo "ul'tr‘ator Emmi 1. An openowl: CITEC system oporatos with warm surfaoo wator at 2TB. an evaporator saturation
temporamro of 24‘0, a turbine exit tomporomro of 14°C and cold “oior equal to 3°C. The idool
(isunlropio) woo: from ﬁle turbine is ' K3 ~ _ KT) . a,
a. 53.94 kJﬂcg “7%? ZE‘HSA hag SEA. <85qaq lad K
:fbiﬂoaoa mg ) Tczqvc "Tcuwc 1:. 1135.25 kag \(‘3‘ 53'%0* [OG‘W‘V 996133 = aqugm
UJg‘a‘ngLtQWQZBH‘F (33.05K31m
d. Noon oftho above. 523 : 35:8.5735H= 090ﬁq+$L%v‘50”3"0'30‘tq); X =Q,0\Il$i§ 2. A11 o putcyclo GTEC systom opomtcﬁ with warm surfsco orator at 2?”C, on ovapomtor ooiomtion
tempmlurf: ofld'ﬂ, a turbine exit Dampcram of 14°C and cold wotor at 8°C. If tho actual work
domed from tho Lmhioo is 66.? kakg, tho tmbino oﬁ‘toionoy is 1:. om: : . vs.
a] w  0.305
4:. £1.95 €3.03‘45ha3. Page 3 of 1D :1. {LEE 3. An openueyele DTEC system operates oath mm smfeee water at E'FC. an evaporator saturation
temperature ofﬂnC, a turbine exit temperature of 14°C and cold water at 3°C. The actual work derived from the turbine is 66.? kakg. Determine the mass ﬂow rate required to extreet lﬂﬂ kW from the
airline. s. seeker do = 129.93. 3 \DOW : Mm 1Ctit/5
I. 3.5m... 03w: unsettle
e. 2.351tgfs @te of the age)
4. A11 opencycle DTEC system operates with warm surface water at ETC. an evaporator saturation temperature of 24°C, a turbine exit temperature of 14°C and cold water at 3°C. The eetnal work derived
front the turbine is 66.? kJJ'kg. The enthalpyr of the ﬂuid exiting the turbine is e. 25W.3 kJr’ltg
b. 2645.8 ktkg ha: “33‘ mm «’— 26 L‘iB.‘‘mi!% e W ,7} 65%“ ZH’W 3%? 24%?ka ,. m”'""""'"* It.‘ ......u.r'I I .1. 2735.5 1(1ka 5. A 3 meter ocean wave has a period of 5 seconds. The wavelength is
s. 45 m l:. 26m
E 39? 7x: \Bﬂo "CZ : LLSGXSQIQz seem :1. None of the above 45. A 3 meter ocean wave has a period of 5 seconds. The wave speed is b. 3.5 ma's e. 5.5 mfe Page 4 of ’10
d. 4.5 mite
'f. A 2 meter eeeen wmre has eperied of 5 eecenrie. The density of water is 1025 1:3me and gravity equal
te 9.30? men. The tete] energ}.r densityr is
21. 1006.5 I’m" 1:. 5015an Tg=\ 0% :L Suzie) \“V‘ “W
1% <3) 2mm; l 3mm 5) ________ “M 5 5.0Qbe3’ Sim?— 3. A fuel eell has an email reectien: H; + if}; r ”gem, endideel werk equelte 19303 Jarmﬂ'l. Avegedre‘e number, hi],  6.02e23 eteinefniei, electreneharge = q= 1.602e19 Ceuleinhe. 1heinternel
eell reltnge fer this fuel eeli is a LESV
I: met: Vlhﬁfm laigjlmol 400'“
”MM ....... MR1 ? A
W ”9‘0 L2) (\eoae'mllto c2985
c 2.351.: 9. Fer the idlewing reeetien:L'H+ 4 U: > CD + H; + 5'3ng the enthalpy,»r ef femletien {if the reaetim,
dhﬂmet stenderd temperature and pressure {STP}ie i  F m
a. 38:.65kifmel “Monet?" $3533 I‘m‘ ﬁrmed) W050
3:. eeseeknmol hm reorgsmlmd lh%1‘%.®‘c3lmo\
e. 3i}5.55 Mfmel NR
Fer#W' ‘'— — _. (3 id, _ oi :
(”f a. $1.561:er {m {“033 $6335) “ LRWDBW)
N... Meme” 2 eggx,3o\<:’>lm\ it]. The current eﬁieiene}r efe fuel eell is [135, 1when the eetuel current is 6 me and. 2 electrene are
transferred ever met efreaetent. Aregadre‘s number, bl, = 6.132623 nemsrnml, electron ehmge  q —
1.6ﬂ2el 9 Ceulemhe. The rate at which the preduet is generated is “Ham“..."h FM?” "H“ := \ ,,
e. 3.6ﬁe—li mans (‘1 W, L . 
LEW3’ “M new ,
h. Inese melts , '
m :LO.D(loP‘1’_,__’__.__ .: 3‘ fake—3%
(oesilau .eozanXemcﬁS 3 FagsSpfw c. 8.53:6 mall's d. Nuns pftim shave 11. Extra Credit If: paints} An ocesnthsrmsl energy mnvsrsipn {UTEC} system is ssssmially shat
snaps, wimp the Camp‘t sﬂiciency represents an upper bound on the thermal efﬁciency. For an open
L'ycle OTEC systsm Tlmt ppmtes with warm satfans waits: at 2?"C, an evaporator sstmalion tampsrahsrc pf24°C, Lmbim: exit tsmpmiurs of 149123 and salt! Wm at 3°C, rim (1th pﬂicipnpy ofthp 51:15:11 is a. spas
in (1:125 57 11 Q Q U c 2.78.! +  s33 +8
W P: W
k? 0.34:3} 1mm: “— 2336*?“ ri. nuns pfths shove Problem 1 (8 points) a) Calculate 1h: svailablp (mp1'33»r from a tide with a. 12 meter range and surfapc arcs. equal to 1:6 .112.
Th: density pfwaxsr is 1025 kgr'm and gravity equal In 9. 8]? mfs. Use Frames] 1 {Scensrlu 1}. III. '5: I. Qﬁagli f 10; fiat—ﬁt ﬂ ri'h' 1! {rs 1: {LE (
J‘Ji w {EL} E x. u 3. 1h“) “.3: 3m“: i: T» r: Jill iffyZ} 22.? gig#311 '3‘“ .f'
EliE." :3 C ”7:“ ['(HOMWM 3 :3 a c5 “‘4‘“
in) CaicuIsts ﬂlﬂ available energy1590111 a 11:53 with [[2 master range, surfapas ales pqual to lsﬁ m’, and a
= 0.13625 11'1 when the energy is harvestsd helm ll=1 11an snd t1 = 4 hour. Um PratJpn] 2 {Scenario 2] Page 6 01°10 Problem 2 (24 points) A close—cycle Ocean Thermal Energy Conversion system is depicted in Figure 2. Ammonia is used as the
working ﬂuid. The warm water surface water enters and leaves the evaporator at 28°C and 25°C
respectively. The ammonia exits the turbine at 12°C. The cold water enters and ieaves the evaporator
(condenser) at 5°C and 8°C respectively. The overall heat transfer coefﬁcient for both the evaporator and
condenser is 1400 W/mz. The quality of the ammonia at the turbine exit is 0.988. Vapor
me Turbine Generator Heat Exchanger
(Boiier) Cool Water
Intake Warm Surface Surface Water Cool Water
Water Discharge Discharge Figure 2 a) What is the temperature at the turbine entrance? (3 points) s/3;W\X UK: Page 7 of 10 e) The actual work from the turbine is 12.31 kJ/kg. Determine the efﬁciency of the turbine. (3 points) (“yr _
iwiwfﬂkﬁvk: a, K}\~}(1€§;Efxr.)a& “MW ..._._....,_._M.,. iii d) The mass ﬂow rate of the ammonia is 10,000 kg/s. Determine the power extracted from the turbine
in units of kW. (3 points) (vi = we «r i\ 00 ‘“‘“ 5
3a.. M OW “WW rattan . 6) Determine the evaporator (boiler) surface area. (10 points) Page 8 of 10 f) Extra credit: Determine the warm—water mass ﬂow rate. (4 points) (i
Q r w
" /' ﬂ, .
V \ Meme “1"“ (Dr: ‘33 {£3
{1111935}? "W mm Mm w w MAmWMMMW ” M 51": V3 {23:33 h (“333 ~ 9 :. . r’ f“ r: ,
I‘m {mi/{ﬂ a; 6t; % UT V5266»? Huge53:: . e ‘ Jr?»
U393} 0/ w ”WW. .WWHJJW Problem 3 (26 pomts) ‘ .3 vw‘u‘kq A fuel cell uses methane for its operation, where the overall reaction: CH4 + 02 —> C0 + H2 + Hzoaiq).
Avogadro’s number, N0 = 6.02e23 atoms/mol = 6.02e26 atoms/limo], electron charge = q = 1.602e—19
Coulombs. a) Write an expression for the change in Gibbs free energy for the reaction at a temperature, T. (10
points) m3; 3; :2: . 3x; ﬂ ,3 WW WW ,
mg {33 333;; 3; h N. “WW k b) W111 {he réactlon Bé favorabie When TM Page 10 of 10 e) The actual current and voltage are equal to 1.5 amps and 0.6 V, and the thermal efﬁciency is equal to
0.85. Determine the fuel cell efﬁciency. (4 points) ...
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 Spring '11
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