Experimental Investigation of Various Type Absorber Plates for Solar Air Heaters

Transcription

1 Tarım Bilimlri Drgisi Tar. Bil. Dr. Drgi wb sayfası: Journal of Agricultural Scincs Journal hompag: Exprimntal Invstigation of Various Typ Absorbr Plats for Solar Air Hatrs Nuri ÇAĞLAYAN a, Zliha Dniz ALTA b, Can ETEKİN b a Akdniz Univrsity, Faculty of Enginring, Dpartmnt of Mchatronics Enginring, Campus, 07058, Antalya, TUKEY b Akdniz Univrsity, Faculty of Agricultur, Dpartmnt of Agricultural Machinry, Campus, 07058, Antalya, TUKEY ATICLE INFO sarch Articl Corrsponding Author: Nuri ÇAĞLAYAN, nuricaglayan@akdniz.du.tr, Tl: +90 ( civd: 8 April 04, civd in visd Form: August 04, Accptd: 9 Sptmbr 04 ABSTACT In this study, four diffrnt typs absorbr plats wr dsignd compard of ir nrgtic prformancs. Ths absorbr plats wr formd as a flat plat (Typ I, V-shapd (Typ II, wdg-shapd (Typ III wavy-shapd (Typ IV. Each typ absorbr plat was manufacturd in both aluminum (Al coppr (Cu matrials. Enrgy fficincis of hatrs wr invstigatd with airflow vlocitis of, 3 4 m s - xprimntally compard with ach or. Th rsults showd that fficincy of hatr with coppr absorbr plat bttr than aluminum plat howvr, rsulting air tmpratur from hatr with aluminum absorbr plat highr than coopr plat. Th xprimntal rsults hav shown that Typ IV Typ II achivd highst nrgy fficincy, rspctivly. Kywords: Solar air hatr; Absorbr plat; Airflow vlocity; Enrgy fficincy Hava Isıtıcılı Günş Kollktörlri İçin Farklı Tip Yutucu Plakaların Dnysl İnclnmsi ESE BİLGİSİ Araştırma Makalsi Sorumlu Yazar: Nuri ÇAĞLAYAN, E-posta: nuricaglayan@akdniz.du.tr, Tl: +90 ( Gliş Tarihi: 8 Nisan 04, Düzltmlrin Glişi: Ağustos 04, Kabul: 9 Eylül 04 ÖZET Bu çalışmada hava ısıtıcı kollktörlr için dört farklı tip yutucu plaka tasarlanmış v bunların nrjik prformansları karşılaştırılmıştır. Bu yutucular, düz (Tip I, V (Tip II, trapz (Tip III v dalga (Tip IV şklindki plakalardan oluşmaktadır. Hr tip yutucu hm alüminyum (Al hm d bakırdan (Cu imal dilmiştir. Isıtıcıların nrji vrimlri, 3 v 4 m s - hava hızında dnysl olarak inclnmiş v karşılaştırılmıştır. Eld diln sonuçlara gör, bakır yutucu plakalı ısıtıcının, alüminyum yutucu plakalıdan daha vrimli olduğu, ancak alüminyum yutucu plakalı ısıtıcının çıkış hava sıcaklığının bakır plakalıdan daha sıcak olduğu görülmüştür. Dnysl sonuçlara gör n yüksk nrji vrimlri sırasıyla IV.v II. Tip yutucu plakalı ısıtıcılarda ld dilmiştir. Anahtar Klimlr: Hava ısıtmalı kollktör; Yutucu plaka; Hava akış hızı; Enrji vrimi TAIM BİLİMLEİ DEGİSİ JOUNAL OF AGICULTUAL SCIENCES ( Ankara Ünivrsitsi Ziraat Fakültsi

2 Exprimntal Invstigation of Various Typ Absorbr Plats for Solar Air Hatrs, Çağlayan t al. Introduction Th us of solar air hatr has bn incrasing in rcnt yars, bcaus of ir simplicity, chapnss, as of ir maintnanc opration, frindly for nvironmnt non-ful opration. Such hatrs ar implmntd in many applications that rquir low to modrat tmpratur blow 60 C (Gupta & Kaushik 008. In agricultural ara, main application of solar air hatr is drying by mans of solar drying. Using a solar dryr, drying tim can b shortnd by about 65% compard to natural sun drying bcaus, insid dryr, it is warmr than outsid; quality of drid products can b improvd in trms of hygin, clanlinss, saf moistur contnt, color tast; product is also compltly protctd from rain, dust, inscts, rodnts; its payback priod rangs from to 4 yars dpnding on rat of utilization (Eliçin & Saçılık 005. Th quality of drid product is mostly dpndnt on drying air tmpratur, vlocity drying tim (Aktaş t al 0; Tülk & Dmiray 04. On or h, rmal fficincy of solar air hatr has bn found to b poor du to low hat transfr capacity low hat conductivity of air. Thrfor, svral rsarchrs hav studid to dsign svral typs of solar air hatrs to improv ir prformanc (Youcf-Ali 005; Kurtbaş & Turgut 006; Gao t al 007; Esn 008; Varol & Öztop 008; Luna t al 00. Ayadi t al (04 invstigatd prformanc of two componnts of a solar drying unit (collctor storag systm without drying nrgy supplmnt. Thy usd a V-corrugatd absorbr singl glazing in air collctor mtal paralllpipd systm for storag unit. According to ir xprimntal rsults, avrag collctor fficincy outlt tmpratur wr found as 30.5% C, rspctivly. Karim & Hawladr (006 prsntd a prformanc study on V-groov solar air collctor for drying application V-corrugatd collctor was found bttr rmal fficincy (about % mor fficincy compard to flat plat collctor. In ir study hight of V dimnsions of absorbr plat wr slctd as 0 cm.8 m x 0.7 m, rspctivly. Absorbr matrial was black-paintd mild stl numbr of glazing was on. Karim t al (0 also dvlopd a mamatical modl for this typ collctor compard simulation rsults carrid out using MATLAB with xprimntal study. Ho t al (0 invstigatd collctor fficincy of upward-typ doubl-pass flat plat solar air hatrs with fins attachd xtrnal rcycl ortically. Collctor fficincy incrass as airflow rat, numbr of fins attachd incidnt solar radiation incras. Considrabl improvmnt in collctor fficincy is also obtainabl if opration is carrid out with xtrnal rcycling. Bn-Amara t al (005 prsntd xprimntal rsults of a nw-dsign plat collctor usd to hat air in a nw dsalination humidification dhumidification procss. In addition, ffcts of diffrnt paramtrs on collctor fficincy, such as solar radiation, wind vlocity, ambint tmpratur, air mass flow rat, air tmpratur humidity through collctor was invstigatd. Kurtbaş & Durmuş (004 invstigatd ffct of airflow lin on prformanc of solar collctors with absorbr slics having four diffrnt surfac gomtris. Th fficincy of collctors incrass dpnding on collctor surfac gomtry xtnsion of airflow lin. As a rsult, it appars that if surfac roughnss is incrasd, hat transfr prssur loss incrass. Karslı (007 dtrmind first scond law fficincis of four typs of air hating flat plat solar collctors; finnd with an angl of 75, finnd with an angl of 70, with tubs a bas collctor. As a rsult, highst nrgy fficincy (80% air tmpratur ris wr found for collctor finnd with angl of 75, whras lowst valus wr obtaind for bas collctor. Mittal t al (007 compard ffctiv fficincy of a solar collctor with diffrnt gomtry typ having roughnss lmnts on absorbr plat. In this study, rlativ roughnss hight 460 Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

3 Hava Isıtıcılı Günş Kollktörlri İçin Farklı Tip Yutucu Plakaların Dnysl İnclnmsi, Çağlayan t al is considrd as strong paramtr of roughnss lmnt for ffctiv fficincy of solar collctor. It is obsrvd that among all roughnss lmnts invstigatd, inclind ribs having low valus of roughnss hight rsultd in bttr ffctiv fficincy in highr rang of ynolds numbr (mor than 000. Howvr, in lowr rang of ynolds numbr (lss than 000, bttr ffctiv fficincy is obsrvd for solar air hatrs having xpd mtal msh as artificial roughnss lmnt. Furr, it is obsrvd also that ffctiv fficincy of solar air hatr is bttr than roughnd solar air hatrs in rang of vry high ynolds numbr. Karwa & Chauhan (00 prsnts rsults of prformanc of solar air hatr with 60 v-down discrt rctangular cross-sction rpatd rib roughnss on airflow sid of absorbr plat. Th ffcts of various ambint, opration dsign paramtrs on rmal ffctiv fficincis of air hatrs hav bn invstigatd. Th study shows that, at air mass flow rats lss than about 0.04 kg s - m - of absorbr plat, roughnd duct solar air hatrs provid significant prformanc advantag ovr smooth ductd solar air hatr. At mass flow rat of about kg s - m -, ffctiv fficincis of roughnd smooth duct solar air hatrs ar practically sam. Alta t al (00 invstigatd ffcts of mass flow rat (5, m 3 m - h - titl angl (0, 5 30 on fficincis of diffrnt typs of dsignd flat-plat solar air hatrs. It was found that attaching fins on absorbr surfac incrass fficincy of solar air hatr. Th nrgy fficincy of hatr also improvd with incrasing airflow rats du to an nhancd hat transfr to airflow whil tmpratur diffrnc of fluid dcrass at constant tilt angl. This papr prsnts a comparison of nrgy fficincis of solar air hatrs having plats with four diffrnt gomtry typs, two diffrnt matrials (Al Cu for, 3 4 m s - airflow vlocitis. Comparisons of nrgtic conomic advantags of collctors with absorbr plat in diffrnt dimnsions, gomtris matrials ar distinctiv proprtis of this study.. Matrial Mthods.. Exprimntal stup masurmnt procdur In study, two xprimntal solar collctors wr usd mountd as shown in Figur. A singl glazing was chosn in ordr to maximiz radiation impact on absorbr. Dimnsion of collctors ar.9 x 0.8 x 0.0 m y hav insulation thicknss of 0.05 m in bottom sids. Th gap btwn absorbr plat bottom is m. Al Cu absorbr plats thicknss of mm ir surfacs ar paintd matt black. All plats ar dsignd as a portabl. nrgtic conomic advantags of collctors with absorbr plat in diffrnt dimnsions, gomtris matrials ar distinctiv proprtis of this study.. Matrial Mthods.. Exprimntal stup masurmnt procdur In study, two xprimntal solar collctors wr usd mountd as shown in Figur. A singl glazing was chosn in ordr to maximiz radiation impact on absorbr. Dimnsion of collctors ar.9 x 0.8 x 0.0 m y hav insulation thicknss of 0.05 m in bottom sids. Th gap btwn absorbr plat bottom is m. Al Cu absorbr plats thicknss of mm ir surfacs ar paintd matt black. All plats ar dsignd as a portabl. Air inlt Absorbr plat Figur - Th xprimntal solar air hatr Şkil - Dnysl hava ısıtmalı günş kollktörü Air pump air vlocity control unit Thrmal insulation Air outlt Figur - Th xprimntal solar air hatr Şkil - Dnysl hava ısıtmalı günş kollktörü Th schmatic diagrams cross-sctions of absorbr typs ar prsntd in Figur. Th surfac aras of collctors ar.5744,.760, m airflow aras ar , , , m, rspctivly. Th schmatic diagrams cross-sctions of absorbr typs ar prsntd in Figur. Th surfac aras of collctors ar.5744,.760, m airflow aras ar , , , m, rspctivly. In this study, collctor inlt outlt air tmpratur, ambint tmpratur, airflow rat, solar radiation, prssur drop wind vlocity was masurd all of 3 data rcordd by a data loggr. A radial fan with a capacity of 0.4 m 3 s - was usd for ach collctor to provid airflow. Th fan spd airflow rat can b adjustd by an lctrical controllr unit. Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

4 Exprimntal Invstigation of Various Typ Absorbr Plats for Solar Air Hatrs, Çağlayan t al a b c d ( Figur - Th absorbr plats which ar usd in xprimnts: a, flat plat (Typ-I; b, V-shapd (Typ-II; c, Figur - Th absorbr plats which ar usd in xprimnts: a, flat plat (Typ-I; b, V-shapd (Typ-II; wdg-shapd (Typ-III; d, wavy-shapd (Typ-IV, K-typ rmocoupls which ar fixd on a plat c, wdg-shapd (Typ-III; d, wavy-shapd (Typ-IV, K-typ rmocoupls which ar fixd on a Şkil - Dnmlrd kullanılan yutucu plakalar: a, Düz plaka (Tip-I; b, V şkilli (Tip-II; c, trapz (Tip-III; d, dalga plat şkilli (Tip-IV v, hava ısıtmalı günş kollktörü üzrin yrlştirilmiş K-tipi ısıl çiftlr Şkil - Dnmlrd kullanılan yutucu plakalar: a, Düz plaka (Tip-I; b, V şkilli (Tip-II; c, trapz (Tip-III; d, dalga In şkilli this study, (Tip-IV collctor v, hava inlt ısıtmalı outlt günş air kollktörü tmpratur, üzrin ambint yrlştirilmiş tmpratur, K-tipi airflow ısıl çiftlr rat, solar radiation, prssur drop wind vlocity was masurd all of data rcordd by a data loggr. A radial fan with a capacity of 0.4 m 3 s - was usd for ach collctor to provid airflow. Th fan spd airflow rat can b adjustd Inlt by an lctrical outlt controllr air tmpratur, unit. absorbr collctor was masurd using a global radiation surfac ambint tmpratur wr masurd snsor (Dlta-T ES accuracy: ±3% at 0 C. Th using Inlt K-typ outlt rmocoupls. air tmpratur, Wind absorbr vlocity surfac was radiation ambint snsor tmpratur was placd wr masurd on glass using covr K-typ of masurd rmocoupls. using Wind a cup vlocity anmomtr was masurd (Dlta-T using A00 a cup anmomtr collctor. (Dlta-T All of A00 snsors modl, wr connctd accuracy: % to a ± 0. modl, m s -. accuracy: Anmomtr % was ± 0. placd m sabout -. Anmomtr m abov collctor. A flow mtr (Tsto 405, accuracis: ± 0. m data loggr Dlta-T Modl DL masurmnts was s - ± placd 5% of m.v. about at 0- m m abov s - was usd collctor. masur A flow air inlt vlocity for solar collctor. Incidnt radiation wr stord in 5 minuts intrvals. mtr on (Tsto collctor 405, was accuracis: masurd ± using 0. m a global s - ± 5% radiation of snsor (Dlta-T ES accuracy: ±3% at 0 C. Th radiation snsor was placd on glass covr of collctor. m.v. at 0- m s - was usd to masur air inlt In ordr All of to snsors obtain wr bst connctd rmal fficincy to a data of loggr Dlta-T Modl DL masurmnts wr stord in 5 minuts intrvals. vlocity for solar collctor. Incidnt radiation on collctor sunshin should b fully usd through In ordr to obtain bst rmal fficincy of collctor sunshin should b fully usd through whol yar. For a collctor oprating through whol yar bst ffct would b obtaind whn panl was st 46 with tilt angl of 35. Collctor Tarım paramtrs Bilimlri Drgisi ar summarizd Journal in Tabl of Agricultural. Scincs (

5 Absorbr coating Dull black paint Glazing Singl glass (thicknss of 4 mm Agnt fluid in flow ducts Air Width of duct, W 0.9 m Collctor sid wall hight, h 0. m Air flow duct hight, D 43 mm Lngth of collctor, L.9 m Hava Emissivity Isıtıcılı Günş of Kollktörlri glass covr, İçin εgfarklı Tip Yutucu 0.85 Plakaların Dnysl İnclnmsi, Çağlayan t al Emissivity of absorbr plat, εp 0.95 Emissivity of bottom plat, εb 0.95 Tilt angl, β 35 Insulation whol yar. thicknsss, For a tb, collctor oprating through t 50 mm whol Thrmal yar conductivity bst of ffct insulation, would λ b obtaind W whn m - K - Hat panl transfr was cofficint st with of coppr, tilt angl λcu of Collctor W m - K - paramtrs Hat transfr ar cofficint summarizd of aluminum, λal 0 W m Tabl. K - Hat capacity of coppr, cp, Cu J g - C - F ( /( { xp /( } Hat capacity of aluminum, cp, Al 0.90 J g - C - = mcp AcUL AcUL F mcp (3 T a is ambint air tmpratur. Th hat rmoval factor of collctor is dfind as shown in Equation 3... Enrgy analysis uncrtainty Whr; m is airflow rat; c Th.. Enrgy nrgy analysis balanc for uncrtainty solar air hatrs ar givn p is spcific hat of air at constant prssur F is hatr in Equation (Hottl & Wortz 94; Duffi & Th nrgy balanc for solar air hatrs ar givn in quation fficincy (Hottl factor & Wortz as shown 94; in Equation Duffi & Bckman 4. Bckman 006; Karwa & Chauhan ; Karwa & Chauhan 00. τ α p η I = Qu /( Ac GT ( S = G T {[ ( α ]} ( p ρ (4 c Whr; u is usful nrgy gain; A c is hatr aprtur ara G T is solar radiation intnsity on Whr; hatr surfac. Q u is Th usful usful nrgy nrgy gain gain; can b A c calculatd is by Whr; quationt. is transmittanc of transparnt hatr Q aprtur [ ( u = Ac F ara S U G L Ti T is T a ] solar radiation covr; a p is absorptanc of absorbr plat ( r c is intnsity on hatr surfac. Th usful nrgy Whr; F is hat rmoval factor; S is solar nrgy rflctanc absorbd of by transparnt hatr; U L is covr. ovrall Th hat ovrall losshat gain cofficint; can b Tcalculatd i is inlt by air tmpratur Equation. T a is ambint loss air cofficint tmpratur. is Th sum hat of rmoval top, bottom factor of dg collctor is dfind as shown in quation 3. hat loss cofficints as shown in Equation 5. Qu = Ac F [ S U L ( Ti Ta ] ( F = ( mcp/( AcUL { xp AcUL F /( mcp U } (3 L = U t + U b + U (5 Whr; F Whr; m is hat rmoval factor; S is is airflow rat; c p is spcific hat of air at constant prssur F is hatr fficincy solar factornrgy as shown absorbd in quation by 4. hatr; U L is ovrall Th top hat loss cofficint is prsntd in hat loss cofficint; τ α T p S = G T { i is inlt air tmpratur Equation 6 (Duffi & Bckman 006. [ ( α ]} p ρ (4 c Tabl Whr;τ - Th is proprtis transmittanc of xprimntal of transparnt solar covr; air α p hatr is absorptanc of absorbr plat ρ c is rflctanc of Çizlg transparnt - Dnysl covr. Th hava ovrall ısıtmalı hat kollktörün loss cofficint özlliklri is sum of top, bottom dg hat loss cofficints as shown in quation 5. Collctor U L = paramtrs U t + U b + U Valu (5 Th Absorbr top hat matrial loss cofficint is prsntd in quation Coppr 6 (Duffi or aluminum & Bckman 006. Plat thicknss mm Absorbr coating Dull black paint N σ ( T pm + T a ( T pm + T Glazing Singl glass (thicknss of 4 mm a U t = ( T pm T a + h w + N + f + C (6 Agnt fluid in flow ducts Air 0.33 ε p + N Width of duct, T W pm N h ( N f 0.9 mε p w ε g + Collctor sid wall hight, h 0. m Air Whr; flow duct N hight, is numbr D of transparnt covr; C 43 = mm 50 ( β ; β is hatr tilt angl; T pm is tmpratur Lngth of of collctor, absorbing L plat, f = ( h m w 0.66 hw ε p ( N ; ε p is missivity of Emissivity of glass covr, ε absorbing plat, hw = g Vr ; V r is wind vlocity; = [ ( 00 Tpm ]; ε g is missivity of Emissivity of absorbr plat, ε p 0.95 transparnt Emissivity of covr. bottom Th bottom plat, ε dg hat loss cofficints ar prsntd in quation 7 8, rspctivly: b 0.95 Tilt angl, β U b = λ / L 35 (7 Insulation thicknsss, t b, t 50 mm 5 Thrmal conductivity of insulation, l W m - K - Hat transfr cofficint of coppr, l Cu 385 W m - K - Hat transfr cofficint of aluminum, l Al 0 W m - K - Hat capacity of coppr, c p, Cu J g - C - Hat capacity of aluminum, c p, Al 0.90 J g - C - Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

6 Whr; m is airflow rat; c at rmoval factor; S is solar nrgy absorbd p is spcific hat of air at constant prssur F is hatr fficincy by hatr; U L is ovrall hat loss factor as shown in quation 4. t air tmpratur T a is ambint air tmpratur. Th hat rmoval factor of τ α hown in quation 3. p S = G T {[ ( α ]} p ρ (4 c cul { xp AcUL F /( mcp } (3 Whr;τ is transmittanc of transparnt covr; α p is absorptanc of absorbr plat ρ c is rflctanc of rat; c p is spcific transparnt hat covr. of air Th at constant ovrall prssur hat loss cofficint F is is hatr sum fficincy of top, bottom dg hat loss cofficints as tion 4. shown in quation 5. Exprimntal Invstigation of Various Typ Absorbr Plats for Solar Air Hatrs, Çağlayan t al U L = U t + U b + U (5 ρ c ]} (4 Th top hat loss cofficint is prsntd in quation 6 (Duffi & Bckman 006. tanc of transparnt covr; α p is absorptanc of absorbr plat ρ c is rflctanc of ovrall hat loss cofficint is sum of top, bottom dg hat loss cofficints as N σ ( T pm + T ( T a pm + T U U a t = ( + h (5 N f C T pm T a w + (6 (6 + + p cint is prsntd in quation 6 (Duffi 0.33 ε + N T & Bckman 006. pm ( ε p N h w ε g N + f Whr; N is numbr of transparnt covr; C = 50 ( β ; β is hatr tilt angl; T N Whr; N is numbr σ ( T pm + of T a ( transparnt T pm + T a pm is covr; ( T pm T a + tmpratur h C w + of absorbing plat, f = ( h ambint, inlt outlt air tmpraturs, wind w 0.66 hw (6 ε p ( N ; ε p is missivity of = 50 ( β ; b N + is f hatr ε p spd solar radiation wr masurd with absorbing + N N h ( N f plat, ε tilt angl; T p h (/ w = V + pm is tmpratur w r ; V r ε is wind vlocity; of absorbing g appropriat U = 0(.430 λ cinstrumnts. h[ / L ( 00 (/ Tpm A c] Th ; ε g rsult is missivity a of givn plat, Whr; is rmal conductivity of insulation matrial; is thick transparnt covr. Th bottom dg hat loss cofficints function ar Whr; prsntd in λtrms is in rmal quation of conductivity 7 indpndnt 8, rspctivly: of insulation variabls. matrial; Lt L is thick primtr of hatr; is hatr hight. Th collctor fficincy factor F r of transparnt covr; f = ( C = 50 h( w hw ε βpu ( ; + β is hatr N tilt ; angl; wprimtr b T pm is of uncrtainty hatr; h is in hatr rsult hight. wth, wcollctor,, wfficincy factor F b = λ / L 0. (7 n g plat, f = ( + p is missivity hw 0.66 of absorbing hw ε pplat, ( + h w = N3. 8; Vε p ; is missivity b 0. of r uncrtaintis in indpndnt variabls. If 5 uncrtaintis F = α /( α +Uin L indpndnt variabls ar all V r ; V r r is is wind vlocity; = [ ( 00 Tpm ] ; ε g is missivity givn of α = with Nu Nu sam λ / Dodds, h n uncrtainty in rsult ottom dg hat missivity loss cofficints of transparnt ar prsntd covr. in quation Th bottom 7 8, rspctivly: having Errors Errors s odds uncrtaintis uncrtaintis is givn in in in Equation xprimnts xprimnts (Akpınar can can aris aris from from instrum instrum U b = dg λ / hat L loss cofficints ar prsntd in Equation 006. nvironmnt, nvironmnt, (7 obsrvation, obsrvation, rading rading tst tst planning. planning. In In s s xprimnts xprimnts outlt outlt air air tmpraturs, tmpraturs, wind wind spd spd solar solar radiation / radiation wr wr masurd masurd 7 8, rspctivly: rsult 5 rsult is is a givn givn function function in in trms trms of of indpndnt indpndnt variabls. variabls. Lt Lt w... = w + w + + w ( w,, b uncrtaintis in n indpndnt variabls. If U b = λ / L (7, w x,, w n b x uncrtaintis xin indpndnt variabls. If t variabls n variabls ar ar all all givn givn with with sam sam odds, odds, n n uncrtainty uncrtainty in in rsult rsult hav hav (Akpınar (Akpınar U = ( λ c h / L (/ Ac (8 / For xampl, total uncrtainty in / Whr; l is rmal conductivity of insulation masurmnt of ambint air tmpratur... (w w Ta matrial; L is thicknss of insulation matrial; may b calculatd as from... Equation = w + w + + wn x x xn 3 c is U = primtr ( λ c h / L of (/ hatr; A c h is hatr hight. (Ayadi For For xampl, xampl, t al 04. total total uncrtainty uncrtainty in in masurmnt masurmnt (8 of of ambint ambint air air tm tm from Th Whr; collctor λ is fficincy rmal conductivity factor F of is insulation calculatd matrial; by Lfrom is quation thicknss quation of 3 insulation 3 (Ayadi (Ayadi t matrial; t al al c is primtr Equation of hatr; 9 h 0. is hatr hight. Th collctor fficincy factor F is calculatd by quation Ta 9 ( w [( ( ( ] Ta = wth + wcp + wtm 0. F = α /( α +U.5 / =0.36 (9 w Ta = [( ( ( 0.5 ] =0.36 L (9 (3 Ta Whr; Whr; w th,, arisn from rmocoupl; cp arisn from connction α = Nu λ / D h (0 th,, arisn from rmocoupl; w cp, arisn from connction p masurmnt. masurmnt. Whr; w th,, arisn from rmocoupl; (0 w cp, Errors uncrtaintis uncrtaintis in xprimnts xprimnts can aris from arisn instrumnt from connction slction, condition, points; w calibration, nvironmnt, obsrvation, rading tst planning. In s xprimnts, During xprimnts, mass flow rat, total ambint, uncrtaintis tm, arisn from inlt of masurd paramtrs can aris from instrumnt slction, condition, tmpratur During masurmnt. xprimnts, total uncrtaintis of masurd paramtrs w outlt air tmpraturs, wind spd solar radiation wr masurd with appropriat instrumnts. Th calibration, rsult is a givn nvironmnt, function obsrvation, in trms of rading indpndnt variabls. Tabl - Uncrtaintis Lt w b of uncrtainty paramtrs in during rsult xprimnts Tabl During - Uncrtaintis xprimnts, of paramtrs total uncrtaintis during xprimnts of tst wplanning., w,, In w n s b xprimnts, uncrtaintis in mass flow indpndnt rat, Çizlg - Dnmlrdki paramtrlrin blirsizliklri variabls. Çizlg masurd - If Dnmlrdki paramtrs uncrtaintis paramtrlrin wr prsntd indpndnt blirsizliklri Tabl. variabls ar all givn with sam odds, n uncrtainty in rsult having s odds is givn in quation Paramtr (unit Commnt Tabl (Akpınar - Uncrtaintis 006. of paramtrs during xprimnts Paramtr (unit Commnt Uncrtainty in masurmnt of tmpratur / Uncrtainty in masurmnt of tmpratur Çizlg - Dnmlrdki paramtrlrin blirsizliklri Ambint air tmpratur ( C ± Ambint air tmpratur ( C ±0.368 w = w w wn Inlt air tmpratur ( C ( ±0.65 Paramtr (unit x x x - n Commnt Inlt air tmpratur ( C ±0.65 Outlt air tmpratur ( C ± Outlt air tmpratur ( C ±0.368 Uncrtainty in masurmnt of mass flow rat (m For Uncrtainty xampl, in total masurmnt uncrtainty of in tmpratur masurmnt of ambint air tmpratur (w Ta may b calculatd as ±0.65 Uncrtainty in masurmnt of mass flow rat (m Uncrtainty in masurmnt of wind spd (m from quation 3 (Ayadi t al 04. s - ± Ambint air tmpratur ( C ±0.5 Uncrtainty ±0.368 in masurmnt of wind spd (m s Uncrtainty in masurmnt of solar radiation (W w [( ( ( ] ±0.5 ± / Uncrtainty in masurmnt of solar radiation (W s Ta = Inlt w air tmpratur th + wcp + ( C w ±0.65 ( ±0.53 tm - Outlt air tmpratur ( C w = [ ( ( ( 0.5 ] Total uncrtainty ±0.368 for collctor rmal fficincy can b writtn as in quatio =0.36 Total uncrtainty for collctor rmal fficincy (3 can b writtn as in quatio Uncrtainty Ta in masurmnt of mass flow rat (m s - ±0.65 Whr; w th,, arisn from rmocoupl; w cp, arisn from connction points; w Uncrtainty in masurmnt of wind spd (m s - tm, arisn from tmpratur ±0.5 masurmnt. wη η m η η η η = Ta Tin Tout Uncrtainty in masurmnt of solar radiation (W s - wm + w + Ta w + Tin w + η ±0.53 Tout m T a Tin Tout V a in out During xprimnts, total uncrtaintis of masurd paramtrs 0.65 wr prsntd in Tabl η [( 0.65 ( ( 0.65 ( ( w = ( η 464 Tabl - Uncrtaintis of Tarım paramtrs Bilimlri during Drgisi xprimnts Journal of Agricultural Scincs ( Çizlg - Dnmlrdki paramtrlrin blirsizliklri sults sults Discussions Discussions Paramtr (unit Commnt Exprimnts Exprimnts wr wr prformd prformd btwn btwn 9 9 th th July July st st Sptmbr Sptmbr 0 0 a Uncrtainty in masurmnt of tmpratur Turky - Ambint air tmpratur ( C Turky (36 ±0.368 (36 N latitud; latitud; E longitud. longitud. All All hatrs hatrs wr wr placd placd facin facin Th xprimnts wr carrid out at sam tim priods btwn 08:30 - Inlt air tmpratur ( C Th flow ±0.65 xprimnts wr carrid out at sam tim priods btwn 08:30 rat data collctd ach min during xprimnts, but - Outlt air tmpratur ( C flow ±0.368 rat data collctd ach 5 min during xprimnts, but -

7 Çizlg - Dnmlrdki paramtrlrin blirsizliklri Paramtr (unit Commnt Uncrtainty in masurmnt of tmpratur - Ambint air tmpratur ( C ± Inlt air tmpratur ( C ± Outlt air tmpratur ( C ±0.368 Uncrtainty in masurmnt of mass flow rat (m s - ±0.65 Hava Uncrtainty Isıtıcılı Günş in Kollktörlri masurmnt İçin of Farklı wind Tip spd Yutucu (m Plakaların s - Dnysl İnclnmsi, ±0.5 Çağlayan t al Uncrtainty in masurmnt of solar radiation (W s - ±0.53 Total Total uncrtainty uncrtainty for collctor for collctor rmal rmal fficincy fficincy can b writtn can b as in writtn quation as 4 in Equation / η η η η η η w = w w a w w w r w η m + T Ta + Tin + Tout + Vr + GT m T Tin T Vr G a in out r T ( / w = =. (5 η [( ( ( ( ( ( ] sults Discussions 3. sults Discussions Exprimnts wr prformd btwn 9 th th July st st Sptmbr 0 at Akdniz Univrsity, Antalya, Exprimnts Turky (36 N wr latitud; prformd 30 E longitud. btwn All 9 th hatrs July wr placd facing south with a tilt angl of 35. Th xprimnts st Sptmbr wr 0 carrid at out Akdniz at sam Univrsity, tim priods btwn 08:30 7:00 of days for a fixd air Antalya, flow rat Turky data (36 collctd N latitud; ach 530 min E during longitud. xprimnts, but rsults wr discussd valuatd whr solar radiation ar mor than 630 W m All hatrs wr placd facing south - - (Ion & Martins 006. with a tilt angl Th nrgy of 35. fficincis Th xprimnts of Al Cu wr absorbr carrid typs out (Typ I, II, III IV wr compard with ach or at for airflow sam vlocity tim priods of m s - - btwn (Figur :30 7:00 of days for a fixd air flow rat data collctd ach 5 min during xprimnts, but rsults wr discussd valuatd whr solar radiation ar mor than 630 W m - (Ion & Martins Figur 4- Enrgy fficincis of Typ-II Th nrgy fficincis of Al Cu absorbr collctors with Al Cu absorbr plat ( m typs (Typ I, II, III IV wr compard with s ach or for airflow vlocity of m s - (Figur - airflow vlocity 3-6. Şkil 4- Al v Cu yutucu plakalı Tip-II kollktörlrinin nrji vrimlri ( m s - hava hızında Figur 3- Enrgy fficincis of Typ-I collctors with Al Cu absorbr plat ( m s - airflow vlocity Şkil 3- Al v Cu yutucu plakalı Tip-I kollktörlrinin nrji vrimlri ( m s - hava hızında Figur 5- Enrgy fficincis of Typ-III collctors with Al Cu absorbr plat ( m s - airflow vlocity Şkil 5- Al v Cu yutucu plakalı Tip-III kollktörlrinin nrji vrimlri ( m s - hava hızında Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

8 Exprimntal Invstigation of Various Typ Absorbr Plats for Solar Air Hatrs, Çağlayan t al Figur 6- Enrgy fficincis of Typ-IV collctors with Al Cu absorbr plat ( m s - airflow vlocity Şkil 6- Al v Cu yutucu plakalı Tip-IV kollktörlrinin nrji vrimlri ( m s - hava hızında Maximum minimum nrgy fficincis of collctors ar for Typ I with Al absorbr plat, for Typ I with Cu absorbr plat, for Typ II with Al absorbr plat, for Typ II with Cu absorbr plat, for Typ III with Al absorbr plat, for Typ III with Cu absorbr plat, for Typ IV with Al absorbr plat, for Typ IV with Cu absorbr plat, rspctivly. Minimum fficincy valus ar shown in midday in consqunc of rduction of rats btwn inlt outlt tmpratur diffrnc solar radiation. Th highst nrgy fficincis wr obtaind in air collctors with Cu absorbr plat. Th similar rsults wr found of 3 4 m s - airflow vlocitis (Tabl 3.Th diffrncs of nrgy fficincy rsults btwn collctors with Al Cu absorbrs ar about % quit clos spcially in Figur 5, as a rsult of proximity of surfac airflow aras of plats. Th avrag fficincis of collctors with Al absorbr wr ordrd as h Typ III >h Typ I >h Typ II >h Typ IV for m s - airflow rat,h Typ III >h Typ II >h Typ IV >h Typ I for 3 m s - airflow rat h Typ III >h Typ IV >h Typ II >h Typ I for 4 m s - airflow rat. Typ III was found mor ffctiv than ors for all airflow rat. Th ordrs of nrgy fficincis of collctors with Cu absorbr wr found as h Typ IV >h Typ III >h Typ I >h Typ II for m s - airflow rat,h Typ IV >h Typ II >h Typ III >h Typ I for 3 m s - airflow rat h Typ IV >h Typ I >h Typ II >h Typ III for 4 m s - airflow rat. Typ IV was found mor ffctiv than ors for all airflow rats. Tabl 3- Th achivd valus of fficincis of Typ-I, II, III IV collctors in, 3 4 m s - airflow vlocitis undr solar radiation Çizlg 3- Tip- I, II, III v IV kollktörlrinin, 3 v 4 m s - hava hızında v günş ışınımı altında ld diln vrim dğrlri Shap of absorbr plat st collctor Typ I (Al Typ II (Al Typ III (Al Typ IV (Al nd collctor Typ I (Cu Typ II (Cu Typ III (Cu Typ IV (Cu Airflow vlocity Wind vlocity T p, T p, T a G T T i, T o, T i, T o, h I, h I, dt/g T dt /G T m s - m s - C C C W m - C C C C % % Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

9 Hava Isıtıcılı Günş Kollktörlri İçin Farklı Tip Yutucu Plakaların Dnysl İnclnmsi, Çağlayan t al Th nrgy fficincis of collctors with corrugatd absorbr plat wr xpctd to find highr than collctor with flat plat in all circumstancs. Incrasing airflow aras of absorbr plats will hlp to undrst rasons of s diffrncs. In Figur 7-0, rsults ar also plottd for Al absorbr plat at, 3 4 m s - airflow vlocitis. As is xpctd, with incrasing mass flow, rmal fficincy incrasd. Figur 9- Enrgy fficincis of Typ-III collctors with Al absorbr plat in, 3 4 m s - airflow vlocity Şkil 9-, 3 v 4 m s - hava hızlarında Al yutucu plakalı Tip-III kollktörlrinin nrji vrimlri Figur 7- Enrgy fficincis of Typ-I collctors with Al absorbr plat in in, 3 4 m s - airflow vlocity Şkil 7-, 3 v 4 m s - hava hızlarında Al yutucu plakalı Tip-I kollktörlrinin nrji vrimlri Figur 0- Enrgy fficincis of Typ-IV collctors with Al absorbr plat in, 3 4 m s - airflow vlocity Şkil 0-, 3 v 4 m s - hava hızlarında Al yutucu plakalı Tip-IV kollktörlrinin nrji vrimlri Figur 8- Enrgy fficincis of Typ-II collctors with Al absorbr plat in in, 3 4 m s - airflow vlocity Şkil 8-, 3 v 4 m s - hava hızlarında Al yutucu plakalı Tip-II kollktörlrinin nrji vrimlri Th tmpratur diffrncs btwn outlt inlt airflows for ach typ of collctors with Al absorbr ar plottd in Figur -3. Th avrag tmpratur diffrncs of collctors wr found as 3.35, 37.84, 37.5, 3.35 C for m s - airflow vlocity, 33.66, 36.93, 35.4, C for 3 m s - airflow vlocity, 33.98, 36.6, C for 4 m s - airflow vlocity, rspctivly. Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

10 Exprimntal Invstigation of Various Typ Absorbr Plats for Solar Air Hatrs, Çağlayan t al Figur - Th variations of tmpratur of Typ- I, II, III IV collctors with Al absorbr plat in m s - airflow vlocity undr solar radiation Şkil - Al yutucu plakalı Tip-I, II, III v IV kollktörlrinin günş ışınımı altındav m s - hava hızındaki sıcaklık dğişimlri Figur 3- Th variations of tmpratur of Typ- I, II, III IV collctors with Al absorbr plat in 4 m s airflow vlocity undr solar radiation Şkil 3- Al yutucu plakalı Tip-I, II, III v IV kollktörlrinin günş ışınımı altında v 4 m s - hava hızındaki sıcaklık dğişimlri 0.045, for 3 m s - air vlocity as , for 4 m s - air vlocity as for Typ III; for m s - air vlocity as , for 3 m s - air vlocity as , for 4 m s - air vlocity as for Typ IV, rspctivly. Figur - Th variations of tmpratur of Typ- I, II, III IV collctors with Al absorbr plat in 3 m s airflow vlocity undr solar radiation Şkil - Al yutucu plakalı Tip-I, II, III v IV kollktörlrinin günş ışınımı altında v 3 m s - hava hızındaki sıcaklık dğişimlri Th avrag variation of tmpratur diffrnc with solar radiation for collctor with Al Cu absorbrs wr found for m s - air vlocity as , for 3 m s - air vlocity as , for 4 m s - air vlocity as for Typ I; for m s - air vlocity as , for 3 m s - air vlocity as , for 4 m s - air vlocity as for Typ II; for m s - air vlocity as Th flow ynolds numbr in solar air hatrs rangs as about , for, 3 4 m s -, rspctivly. 4. Conclusions In this xprimntal study, four-collctor typ s combination with Al Cu absorbr plat was tstd for, 3 4 m s - airflow vlocity compard among mslvs. From this study, following conclusions could b drawn. Efficincy of collctor is vry much dpndnt on airflow rat as fficincy incrasd with flow rat, outlt tmpratur dcrasd corrspondingly. Th maximum collctor fficincis wr found for all typs of collctor with Cu absorbr plat, bcaus hat transfr cofficint of Cu (385 W m - K - is highr than Al (0 W m - K Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

11 Hava Isıtıcılı Günş Kollktörlri İçin Farklı Tip Yutucu Plakaların Dnysl İnclnmsi, Çağlayan t al Th maximum valus of variation of tmpratur diffrnc with solar radiation wr found for all typs of collctors with Al absorbr. Th hat capacity of Al (0.90 J g - C - is highr than Cu (0.385 J g - C -, thus it sms that aluminum absorbr plat accumulats mor hat its hat transfr taks longr tim than coopr absorbr plat. In addition, tmpratur of aluminum absorbr plat is highr than coopr absorbr plat. According to comparison of xprimntal rsults for collctor typs, highst collctor fficincis wr found as h Typ III = 45.56, h Typ = h = for Typ III with Al III Typ III absorbr plat in, 3 4 m s - airflow vlocity, rspctivly. Al absorbr plat in, 3 4 m s - airflow vlocity, rspctivly h Typ IV = 45.86, h Typ IV = 46.8 h Typ IV = 47.8 for Typ IV with Cu absorbr plat in, 3 4 m s - air flow vlocity, rspctivly. Th highst variation of tmpratur diffrnc with solar radiation was achivd by collctor of Typ III for m s - (dt/gt= for Al absorbr dt/gt= for Cu absorbr. According to findings, diffrncs of outlt tmpraturs nrgy fficincis btwn aluminum coopr absorbr plats ar insignificant to rcommndd tmpratur for solar air hatrs. Espcially, cost of collctor with aluminum absorbr plat chapr than with coopr absorbr plat aluminum matrial wight lss than coopr matrial. For futur invstigations, it is suggstd that, incrasing diffrncs of surfac airflow aras of absorbr plats will hlp to compar absorbr plats in trms of fficincy conomy, mor clarly. Acknowldgmnt Th authors ar gratful to Scintific sarch Projct Units of Akdniz Univrsity for funding. frncs Akpınar E K (006. Mamatical modlling of thin layr drying procss undr opn sun of som aromatic plants. Journal of Food Enginring 77(4: Aktaş M, Şvik S, Doğan H & Öztürk M (0. Drying of tomato in a photovoltaic rmal solar-powrd continuous dryr. Tarım Bilimlri Drgisi - Journal of Agricultural Scincs 8: Alta D, Bilgili E, Ertkin C & Yaldız O (00. Exprimntal invstigation of thr diffrnt solar air hatrs: Enrgy xrgy analyss. Applid Enrgy 87: Ayadi M, Mabrouk S B, Zouari I & Bllagi A (04. Simulation prformanc of a solar air collctor a storag systm for a drying unit. Solar Enrgy 07: Bn-Amara M, Houcin I, Guizani A A & Maalj M (005. Efficincy invstigation of a nw-dsign air solar plat collctor usd in a humidification dhumidification dsalination procss. nwabl Enrgy 30(9: Duffi J A & Bckman W A (006. Solar Enginring of Thrmal Procss, 3rd dition, Wily Publishrs, Nw York Eliçin A K & Saçılık K (005. An xprimntal study for solar tunnl drying of appl. Tarım Bilimlri Drgisi - Journal of Agricultural Scincs (: 07- Esn H (008. Exprimntal nrgy xrgy analysis of a doubl-flow solar air hatr having diffrnt obstacls on absorbr plats. Building Environmnt 43(6: Gao W, Lin W, Liu T & Xia C (007. Analytical xprimntal studis on rmal prformanc of cross-corrugatd flat plat solar air hatrs. Applid Enrgy 84: Gupta M K & Kaushik S C (008. Exrgy prformanc valuation paramtric studis of solar air hatr. Enrgy 8(33: 69rgyr Ho C D, Yh H M & Chn T C (0. Collctor fficincy of upward-typ doubl-pass solar air hatrs with fins attachd. Intrnational Communications in Hat Mass Transfr. 38( Hottl H C & Wortz B B (94. Prformanc of flatplat solar hat collctors. Transactions of Amrican Socity of Mchanical Enginrs. USA, Vol. 64, pp Tarım Bilimlri Drgisi Journal of Agricultural Scincs (

12 Exprimntal Invstigation of Various Typ Absorbr Plats for Solar Air Hatrs, Çağlayan t al Ion I V & Martins J G (006. Dsign, dvlopmnt tsting of a solar air collctor. (Ed: V Popa, frigrating Tchniqu, Intrnal Combustion Engins, Boilr Turbins. Th Annals of Dunara d Jos Univrsity of Galati, fascicl IV. Publishd by Univrsitata Dunăra d Jos din Galaţi, omania, pp Karim M A & Hawladr M N A (006. Prformanc valuation of a v-groov solar air collctor for drying applications. Applid Thrmal Enginring 6: 30 Karim M A, Prz E & Amin Z M (0. Mamatical modlling of countr flow v-grov solar air collctor. nwabl Enrgy for Sustainabl Dvlopmnt Dcarbonisation 67: 9-0 Karslı S (007. Prformanc analysis of nw-dsign solar air collctors for drying application. nwabl Enrgy 3(0: Karwa & Chauhan K (00. Prformanc valuation of solar air hatrs having v-down discrt rib roughnss on absorbr plat. Enrgy 35(: Kurtbaş I & Durmuş A (004. Efficincy xrgy analysis of a nw solar air hatr. nwabl Enrgy 9(9: Kurtbaş I & Turgut E (006. Exprimntal invstigation of solar air hatr with fr fixd fins: fficincy xrgy loss. Intrnational Journal of Scinc Tchnology : 75 8 Luna D, Jannot Y & Nadau J P (00. An orintddsign simplifid modl for fficincy of a flat plat solar air collctor. Applid Thrmal Engring 30(7-8: Mittal M K, Varun, Saini P & Singal S K (007. Effctiv fficincy of solar air hatrs having diffrnt typs of roughnss lmnts on absorbr plat. Enrgy 3(5: Tülk Y & Dmiray E (04. Effct of hot air drying diffrnt prtratmnts on color drying charactristics of prsimmons. Tarım Bilimlri Drgisi - Journal of Agricultural Scincs 0: 7-37 Varol Y & Öztop H F (008. A comparativ numrical study on natural convction in inclind wavy flat-plat solar collctors. Building Environmnt 43(9: Youcf-Ali S (005. Study optimization of rmal prformancs of offst rctangular plat fin absorbr plats with various glazing. nwabl Enrgy 30: Tarım Bilimlri Drgisi Journal of Agricultural Scincs (