Mathematical Modeling of Hybrid Cooling Tower for Steam Power Plant

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1 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln r. Hshi A.Hussin Elecrechnicl Engineering eprenuniverciy f Technlgy/ Bgdd Eil:rhshi004@yh.c Received n:5/6/0 Acceped n:4/0/0 ABSTRACT An ecnicl nd envirnenl requireens f hybrid cling er in se per pln re represened by decresing f ule er eperure reducing f er nd energy cnsupin nd rking ihu is frin. The presen rk is deved sudy nd deerine he bes cnc ehd f dry nd e er build hybrid cling er.a hree suggesed dels differs in cncing ehd f ir nd er re sudied. Anlysis f hese dels re dependen n he bsic principles f herdynics ss nd he rnsfer ih cnsidering f iniil nd bundry cndiins. The bes del us be giving cceped vlues in ecnicl nd envirnenl requireens. A Cpuer prgr by Mlb is used fr slving he gverning equins nd deerining he suible heicl del. The resuls re indiced h he hird del (ir in series nd er in prllel is he bes in cncing ehd hich sisfied he ecnic nd envirnen requireens.the resuls re recrded nd represened by grphs. Keyrds: Cling Ters Se Per Plns Energy. النمذجة الریاضیة لبرج التبرید المزدوج في المحطة البخاریة الخلاصة إن المتطلب ات الاقتص ادیة والبیي ی ة لب رج التبری د الم زدوج للمحط ة البخاری ة تتمث ل ف ي تخفیض درجة حرارة المیاه الخارجة من ھ والتقلی ل م ن استھلاك المی اه والطاق ة وتوفیر حال ة عمل للمحطة بدون تكون الضباب تجنبا لمضاره السلبیة. یختص ھدا البحث بدراسة وتحدی د الطریق ة الا فض ل ل ربط الج زء الج اف م ع الج زء الرط ب لبن اء ب رج تبری د م زدوج للمحط ة البخاریة. تم اقتراح وتصمیم ثلاثة نماذج ةفلتخم الاحتمالات في الربط لتیاري الماء والھواء لغرض دراستھا والمقارنة بینھا لاختیار النموذج الا فضل اقتص ادیا وبیي یا. بنی ت أس س تق ویم النماذج المقترحة التي أجریت علیھا الدراسة على القواعد الا ساسیة والثرمودینامیكیة لانتقال الحرارة والمادة آخذین بعین الاعتبار الظروف المناخیة. تم استخدام برنامج Mlb لحل المعادلات الحاكمة وتم تحدید النموذج الریاضي الفیزیاي ي لحسابات البرج المزدوج. تم تحدید التصمیم الا مثل في طریقة ربط الجزء الجاف والرطب معا وفق الشروط الحدیة لكل نموذج. أعطت نتاي ج ھده الدراسة بان النموذج الثالث( ربط الھواء على التوالي والماء على التوازي ( ھو الا فضل اقتصادیا وبیي یا حیث أنتج أقل فقد في المیاه وأعطى اقل درجة حرارة خارجة من البرج وكذلك أعطى اقل استھلاك يف الطاقة وحالة عمل للمحط ة ب دون تكون الضباب الغیر مرغوب فیھ.النتاي ج سجلت وتم تمثیلھا بیانیا. 366 PF creed ih pdffcry Pr ril versin.pdffcry.c

2 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Lis f sybls Sybl C A A α A σ p C PV C h h v K K V. L / L / L escripin surfce re f he exchnge surfce re f he rnsfer surfce re f ss rnsfer he cpciy f dry ir he cpciy f vpr he cpciy f er specific enhlpy difference enhlpy evprin l he cefficien Vpr nuber ri f ir ss fl re f dry er ri f er ss fl re f e er ri f ir er l ss fl re f ir Unis ( ( ( ( kj/ kg. K ( kj / kg. K ( kj / kg. K ( kj / kg ( kj / kg ( /. K ( kg / s v n P V V α V σ l ss fl re f er ss fl re f er evprin Cefficien n ( pril ld eperure f e ir pressure vlue vlue f he rnsfer by cnvecin vlue f ss rnsfer by evprin ir huidiy ( kg / s ( kg / s - C ( P 3 ( 3 ( 3 ( ( g / kg 367 PF creed ih pdffcry Pr ril versin.pdffcry.c

3 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Greek sybl Φ + η c α σ σ ϕ Cling er efficiency Cndenser efficiency he rnsfer cefficien by cnvecin re f ss rnsfer cefficien f ss rnsfer huidiy ri - - ( /. K ( / s ( / s (% Abbreviins Sybl CT HCT CT efiniin ry cling er Hybrid cling er e cling er inle er eperure dry er inle ir eperure dry er ss f ir dry er ss f ir e er ir huidiy enrnce f dry er ir huidiy cefficien enrnce f e er ule er eperure dry er ule ir eperure dry er ule er eperure e er INTROUCTION The hery f cling er cing fr cndensin prcess i.e. incing r uging fr he cndenser is bsed n expsing ir r re ccurely expsing he surfce f er he ir nly. This prcess uld cl he ir hever slly nd his is siilr he cling f er vilble n he pl nd sps surfces. There is fser y de by sprying er in he ir. Bh ys include expsing he er 368 PF creed ih pdffcry Pr ril versin.pdffcry.c

4 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln surfce ir[].cling ers re used ih cndensers cled by er decrese he eperure f he er used s ediu f cndensin hen i cquires he herl per ls fr he cndenser. Pup he h er uging fr he cndenser ener he cling er fr he upside hen disribued eqully in drps fr nd i cncs he ir incing he er s shn in he figure (. Cling prcess is perfred inside he er s resul f evpring prin f er hile cncing he ir he rnsfer by ld prcess crrying he se ejeced uside he er nd hus leds high ir huidiy. In ddiin h prin f he sensed he rnsfers fr ir ir nd herefre he eperure f he ir uging fr he er increses. The efficiency f he cling er depends significnly n he huid eperure f he ir incing he er nd henever he eperure f he e ir hile cing inside is l he efficiency f he er ill be incresed. [3]. The verge f he he rnsfer in he er depends n he degree f he e eperure f he incing ir. Resns f using he cling ers: in huge cling nd cndensin unis such s he per sins nd cenrl ir cndiining here i is necessry hve huge uns f er cl he cling liquid. If he eperure f he er cing inside he cndenser is relively high hen e need huge un f er heher he cling uni is ediu r lrge. The efficiency f he cling er depends n he flling: he e eperure f he ir hile cing inside he er he re f he er surfce expsed ir perid f expsure nd he speed f ir fl in he er nd he direcin f he ir fl cpred he flling er (prllel cnrs r crssing [4].The e ype is re cn in lrge cling ers such s in elecricl per generin. I is direc cnc he exchnger in hich h er fr he cndenser nd cling ir ce in direc cnc. The er fls in eiher pen circui r clsed circui. In pen circui cling er is puped in syse f pipes nzzles nd spryers ihin he er. Air fr he sphere eners he er fr he b f he er nd fls uprd hrugh he flling er [5]. The er is clleced he b f he er nd hen re circuled reve re he fr he cndenser. The eperure f he cld er enering he cndenser ill deerine he se cndense eperure nd hence he bckpressure hich ipcs he efficiency f he hle per generin syse [6]. The is is cnsidered s bsic fcr in he e cling er s resul f evpring l re f er hile cling nd his leds fr is. This hs he flling negive ipcs: cplins nd press fr he lcl residence. I crees crrsin nd ice in he djcen res. Prbles pper in he djcen res fr rffic rds (rds nd rilys in cse f huge cling ers [7]. Figure (3 illusres he herl represenin f he psycheric dring f he hybrid er s shn in he figure (. The exernl ir eners he e prin represened pin. Air ces u fr he e prin pin upn cling er. e nice is frin (uside surin curve. H ir leves he dry prin f he herl exchnger pin 3 fer cling er fixed huidiy level nd hen ixes ih ir uging fr he e prin. Mixed ir currens leve 369 PF creed ih pdffcry Pr ril versin.pdffcry.c

5 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln fr he dry nd e prs represened he pin 4 uside he er. e nice h he ixing line (-4 (resuled fr ixing he surrunding ir ih he ejecin ir if n crssed ih he surin curve (huidiy 00% hen here ill n be cndensed uging er nd herefre n is ill pper [90]. Mheicl del f he hybrid cling er (HCT This del cnsiss f hree eleens:- Mheicl del fr e cling er perin (CT Mheicl del fr dry cling er perin (CT. eerinin f x hen cing u fr he er i.e. eperures hen er nd ir currens re uging ih he huidiy cnen f he ir upn leving (x. In rder fcilie he clculins f he hybrid cling er ke in cnsiderin he flling : he er is cnsidered s dibic syse ih he surrunding sphere in cse f sedy se f he er reled disribue regulrly ir nd er uns he er prfile surfce. Mheicl del f e cling er (CT The heicl del f he e cling er perin shll be sudied ccrding Merkl relins [3]. The e er effeciveness igh be expressed s : - η ( /( c ( In rder deerine he evprin nuber Kv e y sr fr he herdynic bsic f he nd ss rnsfer nd equlize er nd ir se. Figure (4 explins he cycle f ir nd er in cling er fr se per pln. Fr equins f er equilibriu nd energy blnce[3] :-. d d.(.... dh. dh + h. dh + h. d.(3..(4 d σ ( da g σ dq α ( da α g α.(5 dh dq α + dh.(6 d Η h. d vg.(7 360 PF creed ih pdffcry Pr ril versin.pdffcry.c

6 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln dq α + h vg d h d.(8 dq α + ( h vg h d.(9. dh α ( g da α + σ ( g.( h vg h da σ σ. da K v.(0.( A A A α σ.( da dh α ( + σ ( ( h g g vg C. d K v α. C ( + ( h σ C p g vg p α Z σ c p K dh h h v. α hg h g h ( h g g g h + + ( (( ( ( σ. c p h g.(3.(4 (5 (6 K v σ. da dh.(7 h h g Mheicl del f dry cling er (CT The del f he dry cling er perin shll be sudied ccrding nure f fl he exchnge. The dry er effeciveness igh be expressed s per he flling relins [34]: 36 PF creed ih pdffcry Pr ril versin.pdffcry.c

7 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Φ Φ. C p { exp((. C C C p. exp( K. A }. C (8 KA. C exp((.( C. C p Φ. C K. A. C exp(( (. C C. C p p (9 (0 Φ K. A. C /( K. A C K. A exp( C + K. A C p K. A exp( C p ( The dry nd e er cncing depends n ype f hybrid cling er nd n he clculin f he in preers nd ccrding bsic f physics heicl relins nd bundry cndiins[567]. ry pr clculin - surin se h ( C p. s ( +. C s ( s (..( PV. + h V.( b- ihu surin s ( h C. +.( CPV. + h p V (3. L + ( L. h 36 PF creed ih pdffcry Pr ril versin.pdffcry.c

8 Mheicl Mdeling f Hybrid Cling N.00 Eng. Tech. Jurnl Vl.30 Ter fr Se Per Pln 363 e pr clculin (6 Suggesed dels There re severl ehds fr cncing f ir nd er fl. In his rk e shll es hree dels find he bes h give he ecnicl nd envirnenl requireens. Figure (5 explins he scheic digr f hybrid cling er cnc ih herl sin Bundry cndiins f suggesed dels L L (. (. (. h L h L h + ( v L L L L (. ( ( Mdel Mdel Mdel 3 s kg / 83 C 50 rking cndiins PF creed ih pdffcry Pr ril versin.pdffcry.c

9 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Cpuer prgr The gverning equins re slved by M lb lnguge hich is used he psycheric digr ih pplied he bundry nd rking cndiins. Figure (9 shs he fl chr f cpuer prgr seps f sluin: RESULTS AN ISCUSSION Figure (0 explin he ule eperure s funcin f. I shs cprisn f fr dels nd 3 he del 3 is he bes del becuse i gives ler er ule eperure hn hers dels Tbles ( nd ( sh he cprisn f herl preers beeen del nd del 3.Mdel gives ule er eperure hile fr del gives Tble (3 shs he resuls f del 3 hich re ule er eperure evprin lsses nd evprin re differen ir huidiy. Fr he bve cprisn e ke del 3 is he bes becuse is ler s h del 3 hs sudied in deep since i is shn be he bes in chieving f n ecnicl nd envirnenl requireens. Figure ( shs he rking se fr del 3 preer ld n ( There is n effec f n n he ule er eperure hen L bu here is n effec sll vlue f L Figure ( represens he effec f pril ld se fr e er n cling er eperure nd evprin re fr del. Als here is n effec L. The cprisn he se cndiins beeen curves f dels nd 3 sh h del 3 give bes rking cndiins hn del ccrding cling er eperure s shn in figures (nd Figure (3 represens he evprin lsses fr del nd.mdel give evprin lsses ler hn del 3 hen er eperures re equl nd increse slly decreses L Figures (4 nd 5 represen cprisn f evprin lsses re fr del 3 ih differen eperures 5 C nd 30C i is nice h he evprin lsses re n exceeds.67% hich equl evprin lsses re fr del The effecs f pril ld preer fr e er n ule er eperure re given hrugh he index (n by flling relin [] :- G G n K V KV ( l / l (7 Tble (4 shs he effec f Kv n ule er eperure fr e er cprisn ih dry er s h I cn be seen h decresed Kv incresing ( Kv 0.36 leds 45 C hile hen Kv.0 5 C. Figure(6 explin he cprisn resuls f del 3 nd ih incresing f Kv hile leds lys ler fr del 3 hn del. Mdel 3 is beer since re decresing ih incresing f kv hn fr del. This prduce high effecives fr del 3 hn del. 0C ϕ 0.7 ϕ 364 PF creed ih pdffcry Pr ril versin.pdffcry.c

10 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Tble ( resuls f del f herl preers L ( kg / s g ( kg Tble ( resuls f del 3 f herl preers ( ϕ 0C ϕ 0.7 L 0.30 C ( ( g kg 9.9 v ( kg / s PF creed ih pdffcry Pr ril versin.pdffcry.c

11 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Tble (3 resuls f del 3 ule er eperure evprin lsses nd evprin re. 0C ϕ 0.4 L ( kg / s ( g kg C ϕ.0 L ( kg / s g ( kg PF creed ih pdffcry Pr ril versin.pdffcry.c

12 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln L 30 C Φ.0 V ( kg / s V % C ϕ 0. L V ( kg / s V % C ϕ.0 L V ( kg / s V % PF creed ih pdffcry Pr ril versin.pdffcry.c

13 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln 5C ϕ 0.7 L V ( kg / s % V Tble (4 clculed e pr preers cprisn. G G c c c c L K V CONCLUSIONS Resuls f his sudy indiced h he cncing ehd f ir in series nd er in prllel fr hybrid cling er give ule er eperure ler hn hers f cncing ehds his leds chse del 3 is he bes del since i sisfied he ecuenicl nd envirnenl requireens. Als he cnc f ir in series nd er in prllel fr hybrid cling er decresed he energy cnsupin ( l f c gses nd rking cndiins ihu is frin. S h e cn kn here is is r n by deerinin f his is very iprn requireen in se per pln. There is n effec f he pril ld cefficien (n n he ule er eperure hen L bu here is n effec sll vlue f L. Finlly here is n effec f ( n in se f rking e cling er.. REFRENCES []. ASHRAE Hndbk-Fundenls (SI 005. []. Bsnjkvic F. Technische Therdynik Verlg Seinkpff reden 965. [3]. Merkel F. Verdunsungsk VI-Frschungshef ( PF creed ih pdffcry Pr ril versin.pdffcry.c

14 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln [4]. Pppe M.. re und Sffuberrgung bei der Verdunsungsk i Gegen- [5]. He Trnsfer Fluids nd Syses fr Prcess nd Energy ApplicinsJsbir Singhediin jnury985. [6]. M.A.ds S.BernrdesTechnischeknische und klgische Anlyse vn Aufindkrferken 004. [7]. Air-Cndiining nd Refrigerin Mechnicl Engineering Hndbk Ed. Frnk Kreih008. [8]. MATLAB7 -- siulink lbx Help versin 7(R [9]. HVAC er Chillers nd Cling Ters- Fundenls Applicin nd Operin Herber. Snfrd III [0]. Aericn Sciey f Heing Refrigering nd Air-Cndiining Engineers Refrigerin Hndbk Aln Gergi986. [] He Trnsfer Tex Bk Third ediin Jhn H. Lienhrd IV / Jhn H venhrd 003. [] Refrigerin nd Air-Cndiining Third ediin A. R. Tr nd T. Kelley 004. [3] Rndll.Jesn SP Cling Technlgies 00. [4] Pul A.LindhlJr. Plue Abeen nd er Cnservin ih he e/dry Cling Ter 00. [5] hp://.envirissin.c.u. [6] hp://.cubicekbllns.cz [7] hp://.science direc.c Figure ndenser nd cling er cnc in se per pln (idc- Ili. 369 PF creed ih pdffcry Pr ril versin.pdffcry.c

15 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Figure ( Hybrid cling er. Figure (3 Therl cycle f hybrid cling er n he psycheric digr. Figure (4 The scheic digr f he cling er subsyse fr he se per pln PF creed ih pdffcry Pr ril versin.pdffcry.c

16 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Figure (5 Scheic digr f hybrid cling er cnc ih herl sin. Figure (6 Mdel fr hybrid cling er (ir in prllel nd er in series. Figure (7 Mdel fr hybrid cling er (ir nd er in series. 363 PF creed ih pdffcry Pr ril versin.pdffcry.c

17 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Figure (8 Mdel 3 fr hybrid cling er (ir in series nd er in prllel. Red d ( ld he psycheric file he r eerinin f he gverning equin required Genere n rbirry rnsfrer disribued regulrly nd represens he chngeble iie Fr ech vlue f he rbirry rnsfer slve he previus equin nd sve he resul ring f he required curve Figure (9 Shs he fl chr f Sluin seps. 363 PF creed ih pdffcry Pr ril versin.pdffcry.c

18 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Mdel Mdel (ir nd er in series (ir prllel er series Mdel Mdel Mdel Figure (0 Cprisn f ule er eperure fr dels nd 3. Figure ( rking se pril ld fr del PF creed ih pdffcry Pr ril versin.pdffcry.c

19 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Figure ( rking se pril ld fr del 3. Figure (3 Cprisn f evprin lsses fr del nd PF creed ih pdffcry Pr ril versin.pdffcry.c

20 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Figure (4 Oule er eperure ih evprin re 5C fr del 3. Figure (5 ule er eperure ih evprin re 30C fr del PF creed ih pdffcry Pr ril versin.pdffcry.c

21 Eng. Tech. Jurnl Vl.30 N.00 Mheicl Mdeling f Hybrid Cling Ter fr Se Per Pln Figure (6 Effec f e pr n cling er eperure fr dels nd PF creed ih pdffcry Pr ril versin.pdffcry.c

CBE 548: Advanced Transport Phenomena II Spring, 2010 Final Exam

CBE 548: Advanced Transport Phenomena II Spring, 2010 Final Exam CBE 548: dnced rnspr Phenen II Spring Finl E Prble. rbirry Frulin f he escripin f Mss rnsfer he ulicpnen Fick diffusiiies re defined ih he flling equins nd cnsrins (BSL p. 767) cr (.) (.) N c (.) be used