PERFORMANCE AND COST ANALYSIS OF DOUBLE DUCT SOLAR AIR HEATERS

Transcription

1 INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN PERFORMANCE AND COS ANALYSIS OF DOUBLE DUC SOLAR AIR HEAERS BASHARIA A. A. YOUSEF, ADAM N. M Abstact is study invlves a mdel t investigate te eect mass lw, cannel det and cllect lengt n te temal em ance and cst beneit ati tw tyes sla ai eates in duble lw mde, lat late cllect wit us media and V-gve absbe. e temal emance was detemined ve a wide ange eating cnditins. It is und tat te duble ass duble duct V-gve absbe is 4% -5% me eicient tan te duble ass lat late cllect wit us media in te lwe duct and te utlet temeatue is inceased by C -8 C even tug it ad a us media in lat late cllect. On te te and it is cncluded tat te ige in cst enegy any aticula cmbinatin lw det, cllect lengt and mass lw ate is at st cllect lengt, small lw det wit ig quantity mass lw at e. Meve, te values duct lengts and dets wic te cst sla enegy is minimized ae dieent dieent values mass lw ates Key wds Flat late cllect, V-gve absbe, emal emance, Cst sla enegy.. INRODUCION Extensive investigatins ave been caied ut n te timum design cnventinal and mdiied sla ai eates, in de t seac eicient and inexensive designs suitable mass ductin dieent actical alicatins. e eseaces ave give tei attentin t te eects design and eatinal aametes, tye lw asses, numbe glazing and tye absbe lat, cugated inned n te temal emance sla ai eates [-4]. Additinal studies t detemine te temal emance sla ai eates ave been cnducted teetically and/ exeimentally, and dieent mdiicatins ae suggested and alied t imve te eat tanse ceicient between te absbe late and ai [5-9]. Hweve, te availability a tl t be used suting te designs sla ai eates, alicatin matematical mdels te analysis descitive data m te dmain exets wuld acilitate te task. A develed Matematical mdel t edict te temal emance and cst eectiveness dieent designs sla ai eates was esented [] and []. is study uses te aementined develed mdel t ind te inluence dieent aametes, suc as mass lw ate, lw cannel det and cllect lengt n te system temal emance and te cst beneit tw tyes sla ai eates in duble lw mde, tese tyes ae lat late cllect wit us media and V-gve absbe. HEOREICAL ANALYSIS In tis sectin, te eat tanse and te cst acts te duble ass sla ai eates ae discussed, wic lead t annual temal enegy gain (AEG and annual cst (AC te systems. e css sectinal views and te temal netwk te tw sla ai eates ae illustated in Figue. In te tw tyes, te ai eates ae cmsed tee lates, te cve, te absbe and te ea back late. e lwe duct as been acked wit a us media.8 sity in tye. e vaius eat tanse ceicients at dieent cmnents te ai eates ae illustated in te temal netwk in Figue. mdel te sla ai tyes and btain tee elative equatins, analysis is based n enegy balance at vaius cmnents te cllect mdels, alng wit te dieent eat tanse ceicients at tei suaces. e assumtins made ae: i. Heat tanse is steady and ne dimensinal ii. e temeatues te glass, absbe and bttm lates vay nly alng te x-diectin te ai lw iii. ee is n leakage m te smt lw cannels iv. e abstin sla adiatin in te cve is neglected insa as it aects lss m te cllect v. Heat lsses tug te nt and back cllect ae t te same ambient temeatue At sme lcatin a lng te lw diectin, te absbed sla enegy eats u te late t a temeatue. In te lat late cllect wit us media, enegy is tanseed m te late at P t te cve tug te adiatin eat tanse ceicient, t te luid in te ue duct tug te cnvectin eat tanse ceicient, and t te luid in te lwe duct tug te cnvectin eat tanse ceicient. Enegy is als tanseed t te us media tug te adiatin eat tanse ceicient. Enegy is tanseed m te us media t te luid in te lwe duct tug te cnvective eat tanse ceicient 4. Enegy is tanseed m te luid lwing in te ue duct at t te cve tug te cnvectin eat tanse ceicient, and m te luid in te lwe duct at t te base late tug cnvectin eat tanse ceicient 5. Enegy als is tanseed m te us media t te bttm late tug te cnvectin eat tanse ceicient eat tanse ceicient 6. Finally enegy is lst t te ambient ai tug te cmbined cnvectin and adiatin ceicient U t tug te cve glass. Figue (a illustates te duble ass duble duct lat late cllect wit us media in te lwe duct and te temal netwk. e steady-state enegy balance gives te llwing equatins: Cllect cve ( U ( ( Fluid Absbe ( c c t c a mc d ( ( ( ( W dx c ( IJSR 8

2 INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN I ( Fluid ( 5 ( ( c mc ( W ( d ( dx 4 ( ( ( (4 Pus media ( ( (5 ( 6 4 Bttm late ( U ( (6 5( 6 b a F V-gve absbe enegy is tanseed m te late at P t te cve tug te adiatin eat tanse ceicient and te cnvectin eat tanse, and t te luid in te ue duct lwing tug te V-gve at a temeatue tug te cnvectin eat tanse ceicient, and t te luid in te lwe duct lwing between te absbe late and te base late at a temeatue tug te cnvectin eat tanse ceicient. Enegy als is tanseed t te base late tug te adiatin eat tanse ceicient. Enegy is tanseed m te luid lwing in te lwe duct at t te base late tug cnvectin eat tanse ceicient 4. Finally enegy is lst t te ambient ai tug te cmbined cnvectin and adiatin ceicient U t tug te cve glass. Figue (b illustates te duble ass duble duct V-gve absbe and te temal net wk. e steady-state enegy balance n te cve, te late and te luid in te ue and lwe gives te llwing equatins: Cllect cve ( ( U ( (7 c c t c a V-gve absbe ( ( ( ( Fluid medium in te ue assage ( mc ( W c d ( dx Fluid medium in te lwe duct ( mc d ( ( ( 4 ( W dx I c (8 (9 ( Bttm late ( U ( ( 4( b a (a ye - (b ye - Figue : Scematic diagam te sla ai eates wit temal netwk. ANNUAL ENERGY GAIN e annual temal enegy gain (AEG available m te cllect can be btained by multilying te useul eat by te numbe eating days in a yea and te numbe us e day duing wic useul sunsine is available []. ( AEG mc ( t. ANNUAL COS In de t estimate te annual cst te cllect (AC te sla ai dieent cst acts ave t be calculated. is includes te annual um cst unning cst (ARC, annual caital cst (ACC, annual maintenance cst (MC and annual salvage value (ASV. e annual unning cst is calculated as llws [] and []: i ARC ( m t CE ( v Wee P is te essue d (Pa, t is te time eatin and CE is te cst electicity (RM/KW m L D (4 IJSR 9

3 Outlet temeatue (C Eeciency (% INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN D y L (5 and y ae 4 / Re, y. 9 lamina lw (Re<55 e values.94, (55<Re< 4.59Re,. 7.5 y.9 Re tansitinal lw y tubulent lw ( 4 < Re< 5 e annual caital cst (ACC is given by te llwing elatins: ACC CRFxCI (6 CI CC CSSC FC (7 CRF i( i n /[( i n ] (8 CC WL *( X Y (D W * LZ (9 e annual salvage value (ASV is given as: ASV SFFxSV ( SFF i /[( i n ] ( SV. CI ( Wee CI is te Caital investment, SFF is te salvage und act and SV is te salvage value eee, te annual cst te cllect (AC is calculated as AC ACC MC ARC ASV (. RESULS AND DISCUSSION cmae te emance te sla ai eates a simila inut data ave been enteed t give te same cniguatin bt duble ass duble duct lat late cllect wit us media in te lwe duct and duble ass duble duct V-gve absbe. e detailed inut data ae given in able able : Seciicatin Sla Ai Heates Cllect tilt angle (degee Cllect lengt (m.4 Cllect widt (m. Plate tye Flat late and V-gve 45 degees Absbe mateial Black steel, =.9 and =.85 Cve mateial Odinay clea glass, =.85 Numbe cve Insulatin mateial Fibe glass, k =.45 W/m.k Back insulatin tickness.5 (m Edge insulatin tickness.5 (m Pus media Glass wall.8 sity duble ass wit us media in lwe duct Figue and sws te vaiatin eiciency and utlet temeatue wit mass lw ate te tw tyes sla ai eates, te eiciency inceased wit te incease mass lw ate as well as te utlet temeatue deceased. e igues sws tat te duble ass duble duct V- gve absbe is 4% -5% me eicient tan te duble ass lat late cllect wit us media in te lwe duct and te utlet temeatue is inceased by C -8 C even tug it ad a us media in lat late cllect. is indicates tat, te V-gve absbe as te signiicant advantage absbing a geate quantity sla adiatin tan te lat late equal abstivity and tat because te multile electins and abstin incident adiatin. Figue 4 sws te vaiatin essue d wit mass lw ate, wee te essue d in duble ass V-gve absbe was less tan tat in duble ass lat late cllect wit us media by Pa t 4 Pa, ence, te use us media incease te essue d Mass lw ate (kg/s Flat late V-gve Figue : e Vaiatin Eiciency wit Mass Flw Rate Flat late V-gve Mass lw ate (Kg/sec Figue : e Vaiatin Outlet emeatue wit Mass Flw Rate IJSR

4 Eeciency (% AC/AEG (RM/KW Eiciency (% Pessue d (Pa INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN Flat late V-gve Mass lw ate (Kg/sec Figue 4: e Vaiatin Pessue D wit Mass Flw Rate e eiciency cuves duble ass lat late cllect wit us media and duble ass V-gve absbe at dieent lw ates ae swn in Figues 5 and 6. e esective eiciency equatins and F R ( and F R U L values ae esented in able and. Fm te igues, it is evident tat te sles te eiciency cuves decease wit incease lw ate, wic means at ige lw ate, te veall lss is lwe. Als it can be seen tat te lss ceicient is ige in te duble ass lat late cllect wit us media and least in V-gve cllect te same lw ate (i-a/i.7 kg/sec. kg/sec.4 kg/sec.5 kg/sec Figue 5: Eiciency Cuve Duble Pass Flat Plate Cllect wit Pus Media in Lwe Duct able : Eiciency Equatins, F R ( and F R U L Duble Pass Flat Plate Cllect wit Pus Media in Lwe duct Flw ate (kg/s F R ( F R U L Eiciency equatin R y 4.87x y 4.87x y 5x y 5x. 58 x ( I (Wee i te inlet temeatue, a te i a ambient temeatue and I te sla islatin able : Eiciency Equatins, F R ( and F R U L Duble Pass V-gve Absbe witut Pus Media in Lwe Duct Flw ate (kg/s F R ( F R U L Eiciency equatin R y.8776x y 4.87x y x y x x ( i a I By using te develed gam, te cst sla enegy (i.e. ati te annual cst te cllect (AC / annual temal enegy gain (AEG te tw sla ai eates tyes wee cmuted at dieent lw dets and mass lw ate. Figue 7 illustates te cst sla enegy wit lwe cannel det at ixed mass lw ate.4 kg/s, cnstant ue det.5 m and dieent lw lengts. e igue sws tat te cst sla enegy is a unctin in cllect lengt ence te cst is educed by inceasing te cllect lengt. 6 4 L =.4 m L =.5 m kg/sec. kg/sec.4 kg/sec.5 kg/sec (i-a/i Figue 6: Eiciency Cuve Duble Pass V-gve Absbe Lw e duct det (m Figue 7: e Vaiatin AC/AEG wit Resect t Lwe Flw Det in Duble Flw Flat Plate Cllect wit Pus Media. IJSR

5 AC\AEG (RM\KW AC/AEG (RM/kW AC/AEG (RM/KW INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN Figue 8 sws te vaiatin te cst sla enegy as a unctin lwe cannel det duble lw mde wit us media dieent mass lw ates. e Figue sw tat as te ai mass lw ate inceases, te cst sla enegy inceases, wic is becmes te igest at small lw dets at mass lw ate.5 kg/s. is is a cnsequence te elatively lage ate uming cst tan te ise enegy wit a decease in duct det and an incease in ai mass lw in te system.. 7 Mass =. Kg/sec Mass =.4 Kg/sec Mass =.5 Kg/sec Lw e lw det (m Figue 8: e vaiatin AC/AEG wit esect t lwe lw det in duble lw lat late cllect wit us media. e esults btained V-gve absbe tyes ae deicted in Figue 9. It sws te cst sla enegy as a unctin lwe lw det wit cnstant lw ate at. kg/s. e cst sla enegy wit esect t lw det at cnstant lw lengt and dieent mass lw ate ae swn in Figue. e cst sla enegy deceased by inceasing te lw det, tis decease in te cst cntinue until it eac te minimum value ten it begin t incease by inceasing te lw det. e gas in all igues eveal tat te ige in cst enegy any aticula cmbinatin lw det, cllect lengt and mass lw ate is at st cllect lengt and lw det wit ig quantity mass lw ate. Meve, te values duct lengts and dets wic te cst sla enegy is minimized ae dieent dieent values mass lw ates L =.8 m L =.5 m L = m Lw e cannel det (m Figue 9: e vaiatin AC/AEG wit esect t lwe lw det V-gve absbe. Figue : e vaiatin AC/AEG wit esect t lw det V-gve absbe dieent mass lw ate. e cst sla enegy as a unctin cllect lengts ixed lwe det wit dieent ue det and ixed ue det wit dieent lwe det duble lw lat late cllect wit us media in te lwe duct ae esented in Figues and Mass lw =. kg/s Cllect lengt (m d-u.5 m d-u.5 m d-u.5 m IJSR

6 AC/AEG (RM/kW INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN Figue : e AC/AEG as a unctin cllect lengt dieent ue det and mass lw wit cnstant lwe det in duble lw ass lat late cllect wit us media. Figue : e AC/AEG as a unctin cllect lengt dieent lwe det and mass lw wit cnstant ue det in duble lw ass lat late cllect wit us media. e cst sla enegy as a unctin cllect lengts ixed lwe det wit dieent ue det and ixed ue det wit dieent lwe det dieent ai mass lw ates te duble ass V-gve absbe ae esented in Figues and Mass lw =. kg/s Cllect lengt (m d-dw n. m d-dw n.5 m d-dw n.7 m IJSR

7 AC/AEG (RM/KW AC/AEG (RM/KW AC/AEG (RM/KW AC/AEG (RM/kW AC/AEG (RM/kW AC/AEG (RM/KW INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN Mass lw =. kg/s Cllect lengt (m d-u. m d-u.4 m d-u.5 m Mass lw =. kg/s Cllect lengt d-dw n.m d-dw n.5m d-dw n.7m.4.5 Mass lw =. kg/s Cllect lengt (m d-dw n. m d-dw n.5 m d-dw n.7 m Mass lw =.5 kg/sec Cllect lengt (m d-u. m d-u.4 m d-u.5 m Mass lw =.5 kg/sec Cllect lengt d-dw n. m d-dw n.5 m d-dw n.7 m.7.6 Mass lw =.4 kg/s Cllect lengt (m d-dw n. m d-dw n.5 m d-dw n.7 m Figue : e AC/AEG as a unctin cllect lengt dieent ue det and mass lw wit cnstant lwe det in duble lw ass V-gve absbe. Figue 4: e AC/AEG as a unctin cllect lengt dieent lwe det and mass lw wit cnstant ue det in duble lw ass V-gve absbe. IJSR 4

8 AC/AEG (RM/KW INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN All te gas -4 sw at ist a all in te cst ten a ise wit an incease in lengt, te eect being geate wit an incease in mass lw and a deceased in lw det (Cuduy et al., 995. e cllect lengt wic te cst is minimized is bseved t decease wit a decease in cllect det and an incease in mass lw ate. Figue 5 is a diect cmaisn te cst te sla enegy (AC/AEG te duble ass lat late cllect wit us media in te lwe duct and te duble ass V- gve absbe witut us media unde identical design and eatinal cnditins. It is swn tat te cst duble ass lat late cllect wit us media is ige tan tat duble ass v-gve absbe in site ige enegy gain is m te duble ass V-gve absbe and tat because te lage ate ise te uming cst because te use us media Duble lw lat w it us media Duble lw V-gve Lwe cannel det (m Figue 5: e AC/AEG as a unctin lwe cllect det duble lw lat lat cllect wit us media and duble lw ass V-gve absbe witut us media. e aementined discussed esults n te eect lw det, lengt and mass lw ate n te cst sla enegy ave te same tend te studies cnducted by [-] and []. 4. CONCLUSION Fm tis study it is und tat te aametes tat aect temal emance and te sla enegy cst te sla ai eates ae mass lw ate, cannel lw det, cllect lengt and te us media. ei aective aeas as llws: - Inceasing te mass lw ate esult in i. Inceasing te cllect temal eiciency ii. iii. Deceasing te utlet temeatue Inceasing te essue d, yet incease te cst sla enegy - Deceasing te lw det cause i. Inceasing te cllect temal eiciency ii. Inceasing te utlet temeatue iii. Inceasing te essue d wic lead t an incease in te uming exand in te cllect tus incease te cst sla enegy - Inceasing te cllect lengt esult in i. Deceasing te cllect temal eiciency IJSR ii. Inceasing te utlet temeatue iii. Inceasing te essue d 4- Using us media esult in i. Inceasing te cllect temal eiciency ii. Inceasing te utlet temeatue iii. Inceasing te essue d wic lead t an incease in te uming exand in te cllect tus incease te cst sla enegy NOMENCLAURES ACC e annual caital cst, RM CC e cst te cllect aay, RM CI e caital investment, RM C Seciic eat wking luid, J/kg K CRF e caital ecvey act CSSC e cllect sut stuctue cst, RM D Flw cannel det, m FC e abicatin cst, RM Fluid eat tanse ceicient, W/m K Radiatin eat tanse ceicient, W/m K I Sla adiatin, W/m i e inteest ate, assumed as 8% L Cllect lengt, m m Cllect lw ate, kg/s m v e vlumetic ate, m /sec MC e maintenance cst, cnsideed t be % te ACC. n e cllect lie, assumed as yeas Rate useul enegy gain, W Q a c i Ambient ai temeatue, K Cve temeatue, K Fluid temeatue, K Fluid inlet temeatue, K Outlet temeatue, K Absbe late suace temeatue, K Pus media temeatue, K U U b t Bttm late temeatue, K Back lss ceicient, W/m K lss ceicient, W/m K W Cllect widt, m X Cst te absbe late, RM/m Y Cst te cve, RM/m Z Cst side wall + bttm insulatin, RM/m GREEK SYMBOLS Sla tansmittance glazing Sla abstance cllect late Density, kg/m 5

9 INERNAIONAL JOURNAL OF SCIENIFIC & ECHNOLOGY RESEARCH VOLUME, ISSUE 6, JULY ISSN REFERENCES [] Ratna Vema, Ram Canda and Gag, H. P. Paametic studies n te cugated sla ai eates wit and witut cve, Renewable Enegy, (/ [] Ratna Vema, Ram Canda, and Gag, H. P. ecnical nte- timizatin sla ai eates dieent designs, Renewable Enegy, (.4/ [] Cuduy, C. Hauan, C.P. M., and Gag, H.P. Pemance and cst analysis tw ass sla ai eates, Heat Recvey System &CHP, 5 ( [4] Kaim, M.A., and Hawlade, M.N.A. Develment sla ai cllects dying alicatins. Enegy Cnvesin and Management, ( [5] Ong, K. S. emal emance sla ai eates: matematical mdel and slutin cedue, Sla Enegy, 55 ( 995a, 9-9. [6] Ong, K. S. emal emance sla ai eates exeimental celatin, Sla Enegy, 55( 995b 9-. [7] Metwally, M. N Abu-Ziyan, H. Z., and El-Leaty, A. M. Pemance advanced cugated duct sla ai cllect cmaed wit ive cnventinal designs. Sla Enegy, ( [8] Ye, H.M., Cii-Dng H, and Jun- Ze, Hu. Cllect eiciency duble lw sla ai eates wit ins attaced, Enegy, ( [9] Fsn, F. K. and Naza M. A. A. Exeimental and simulatin n a single ass, duble duct sla ai eate, Enegy Cnvesin and Management ( [] Basia A.A. Y, N.M. Adam, M. Daud, H. Oma, M.H.M. Amed and S. M. Sauan. Citeia Sla Dying Pjects in Malaysia, Junal Industial ecnlgy (4 4a -. [] Basia A. A. Yuse, N. M. Adam, M. Daud, H. Oma, M. H. M. Amed and Eladi A. Musa. Exet System Based Pedictin te Pemance Sla Ai Cllects in Malaysia, Junal Enegy & Envinment, ( 4b 9- [] Cuduy, C., and Gag H. P. 99. Design analysis cugated and lat late sla ai eates, Renewable Enegy, (5/6, IJSR 6