KHOA HOC CONG NGHE MO PHDIVG BO THU IVAlVG LUOIMG IVIAT TR01 KIEU PHOI HOP SdlMG CHU V VA P H A I V G TROIMG T H | £ T B ! S A Y C A C O M S U OUIMG IMAIMG LUOIMG MAT TROI Nguyen Xuin TrungS Dinh Vuong Hung^, Trin Nhu Khuydn^ Nguyin Thanh Hai^ Ngd Qudc Hung^, TVln Nhu Khlnh^ T6MTAT Bai bao trinh b^y k^t qua mo phong va thuc nghiem bo liiu nang lugng m§t trdi ki^u phoi hop song chir V vk pblog thiet bi say ca com sd dung nang luong mat trtn Trong bO thu, ding kh6ng di theo hinh chu U qua c ^ phan tbu c6 tam thu nhiet phang va tam thu nhi?t song chir V Phfc thu pbang viea d6ng vat trd thu nhiet vua la k^nh dan dd ddi chidu dong kbi G phan thu song chir V, d6ng ti^p xiic song song ca mat trgn va mat diroi t ^ thu dd tang kha nang nhan nhiet Vi^c mo phdng duoc thuc bien bang mo binh toan hoc va phin mdm Matlab Kdt qua m6 phong dtroc so sanh vol ket qui thi nghiem mot dau mua he Nhiet d6 ddng IchSng khoi b6 thu theo mo phong dat cao nhit M 328,9 K, thuc td dat 327,5 K so voi nhiet d6 m6i trudng la 307,2 K, hieu suat mo phong cua bo thu diit cao nh& 54,4% so voi hieu suat thuc td cao nhat dat 50,8% Tit^6a: Mo phdng, bd thu nang Immg mat trdi, phdi hop, song chd V,s^y Thidt hi say ca com su dung nang lugng mat trdi dupe thiet ke va che tao tai bd mdn Thidt bi bao quan va Che bien ndng sin - Khoa Co didn-Hoe vien Nong nghidp Vidt Nam Trong thidt bi say c l com, ^d thu nang lupng mat trdi (bp tfiu nhiet mat trdi hay bd thu) cd chiic nang chuydn biic xa mat trdi nhiet nang de cung d p cho qua trinh sly Trong b6 thu nang lupng mat trdi, tam thu nhi^t dupe lim bang v|t U&u CO hd so hap thu cao biie xa mat trdi vl cd Idp phu den md vdi tic nhan say II kh6ng Hi&n nay, tam thu nhidt dugc su dung phd bien cd dang tam phang Tam fliu lihidt phing cd mi didm clu tao dan gian, dd thay thd v l bao tri vl siia chira nhimg cd nhugc didm II hieu suit thu nhi&t thap dien tich hap thu nhiet nhd Bi: nang cao hidu suit nhiet eua bd thu theo nguydn tac tang didn tich hap thu nhidt, cd nhieu kidu tim thu nhidt khac da dupe nghidn cuu, bao gdm: tam thu nhiet kieu sdng chii V, kidu tam cd canh vl kidu tim ludi can, tam thu nhidt sdng chu VII mot lua chon phu hpp cd hieu suit nhidt cao ban tam thu nhidt phlng, tim thu cd cinh vl it tdn bao cdng suit eho quat hon so vdi tim thu ludi can (Karim vl Hawlader, 2004) Tuy nhi^n, tam tiiu nhi^t kidu sdng chu V cd ' Tnrong Cao dang, Giao thong HuS ^Trucmg Dgi hoc Nong Mm- Dai hoc Hu^ ^ Hgc vien Nong nghiSp Vigt Nam nhupc didm 11 phan kenh din ddi hudng chuydn ddng cua ddng (khi cin lip ghep nhidu bd thu nhiet vdi nhau) thudng nam ngoai b6 thu nhiet nen chua tan dung tri$t de dien tich hip thu nang lupng mat trdi Vi vay, vide nghidn euu bg thu nhiet phdi hpp tam phlng v l sdng chii V vdi tim phlng duge lip dat tai kenh dan ddi hudng chuyen ddng cua ddng II giai phip tich cue de nang cao hidu suit nhiet cua bd thu nhiet Bai bao nly trinh biy kdt qua md phdng bd thu nang lupng mat trdi kidu phdi hgp sdng chu V vl phang lam ca so dd thidt ke, che tao bd thu nhiet thidt hi say e l com su dung nang lupng mat trdi BM TUDIK Vli nWDNG PHAP NGHBII Cliu 2.1 Ddi tupng nghidn cihi Bp thu nang luong mat trdi kidu phdi hgp sdng chii V vl phang (k^ hieu BT-1,0) duge thiet ke vl chd tao tai bd mdn Thidt bi bao quan vl Chd bidn ndng san, Khoa Co dien, Hpc vien Ndng nghidp Viet Nam Bd thu cd dang hmh hop chu: nhit, kich thudc bao ngoii II 3,0 m X 1,0 m X 0,18 m, vd lim bang thep khdng ri diy mm, eJK;h nhidt bang xdp PE - GPP tring nhdm diy 10 mm (hinh 1) Tim tiiu nhiet sdng chii V lam bang nhdm II diy 0,5 mm, son mlu den dupe lip d ben bd thu nhidt cho lam vide ddng di d ca tren v l dudi tim tiiu nhiet Dd ning cao nhiet dp dau eda ddng khi, phan thu NONG NGHIEP VA PHAT TRIEN N N G T H N - KY - THANG 12/2015 43 So KHOA HOC CdNG NGHE sdng chii V dupe chia lim hai ngan ddi xung vdi qua vich ngSn tao nen hai kenh dan song song, dd ddng di bd thu nhiet phai ddi hudng theo kenh din d hai dau bg thu nhiet De tang nang hap thu nhiet tai kenh din d hai diu bd thu cd lap tim thu nhiet dang phang Cua ddng vao vl cd ban sin cic mat bich dd dd dang ndi ghep cic bg thu nhiet vdi can thidt Hinh Clu t?io bd thu nang lupng mitti-dikidu hdn hpp phlng vk sdng chft V I Tam thuphing Tam thu chd V Vach ngan Mat kinh Vo Vat lidu cich nhidt 3.KErqUAVilTHA0LUAN 3.1 Md hinh hda va md phdng bd thu nhidt 3.1.1 Mang nhidt Tu hinh cd the coi bd thu nhiet mat trdi gom nam phan thu ndi tiep nhau, nhidt dd diu cua phin II dau vao cua phan Ida Mang nhidt eua cac phin thu phlng va sdng chu V cua mot kenh din bd thu dupe trinh bay hinh vl De mo hinh hda va md phdng, cic gia thidt cin duge dat II: - Nhiet cua ddng thay ddi tuydn tinh theo chieu dii ddng chay; - Nhiet dd cic be mat ximg quanh ddng \i ddng nhit - Bd qua tdn that nhidt qua cac mat ben cua bp thu; - Su chenh lech nhiet dp giua hai bd mat cua tara kinh, tam hip thu II khdng ding ke; - Tdn that nhiet qua mat diy la truyen nhiet qua tam cich nhiet va gid, buc xa nhiet cua tam each nhiet II khdng dang kd 3.1.2 Cic phuong trinh can bdng nang luong a Phuong trinh cin bang nang lu^/ng cua thi thuphing - Phuong tiinh can bang nang luong cua tam kinh phu: 2.2 Phuong phip nghien ohi - Thidt lap mang nhiet dd mo phdng va tinh toin qua binh tiiiydn nhidt ti-ong bd thu nhiet tirong hi nhu mang dien Qua hinh huydn nhiet giua cic vat dupe coi nhu qua trinh din dien mot mang dien Tdn thIt nhidt qui tiinh trao ddi nhiet d Si+h^,a,-Ti)-HhiCrfi-Ti) = UTcri-Tj (i) elc didm mit dupe tinh tuong tu nhu tdn that dien Vdi buc xa mat ti-di len tim kmh phii duoe tinh bang: Sj = a^ (2) gay bdi dien txb, dugc goi la "nhiet trd" - Phuong trinh can bing nSng lupng cua ddng - Sii dung phuong phap ma tran de giai he phirong trinh can bang nang lupng vdi cac bude lap cin thiet d kenh tren: haCr2-Tfl)=hi(Tfi-TJ-HQj(3) de dam bao dd chinh xac cho phdp Diu tien, nhiet dd gil dinh dupe dimg de tinh toin nhiet dd mdi Tfi Ts Nhung gia hi nhiet mdi dupe so sinh vdi nhiet gia dinh, ndu chenh lenh hon 0,01''C thi gia dmh lai va tidp tuc tinh toin cho den chenh lech nhd hon 0,01"C Ddn luc dd nhiet tinh toin dupe coi la nhiet Dong]—• doti-ungbinh cua mdi thinh phin bp thu - Su dung phan mdm Maflab de md phdng va so sanh voi ket qua thuc nghiem h-en md hinh thuc Nhiet dd vl tdc dp khong d mo hinh thuc dupe bang mIy cim tay Smartsensor AR836 vl buc xa matti-didupe bing may Tenmars TM-206 Theo ket qua tinh toan sa bg thiet bi say ca com Ta su dung nang lupng mat h-oi, yeu clu: nhiet dp khong a) b) dua vio budng sly tdi da 11 50°C (313 K), lupng Hmh Sa dd tinh toin md phdng (a) vl nuing nhidt khong can thidt cho qui tiinh sly 0,4-0,5 kg/s va ctia phin thu phSng (b) thdi gian sly 8-10 gid/me 44 NONG NGHIEP VA PHAT TRIEN N N G T H N - KY - THANG 12/2015 KHOA HOC CdNG HeHE Tfi, TG - Nhidt dd tnmg binh ddng khong b kdnh h-dn vl kenh dudi (K); TS - Nhiet dd blu ti-di, % = 0,0552Tf (K); ^hi bj T n — Qi, Q2 - Nhidt lugng ma ddng d kdnh tren vl dudi nh$n duoc (W/m^; Ub, Uj - He sd thIt tholt nhidt cua mat day, mat kinh (W/mMg; tti, 0:2 - Hd sd hap thu cua tim kinh, tim hip thu; T - Hd sd truyen qua ciia tim kinh 3.1.3 Cdc he sd truydn nhidt Hinh Sa dd tinh toin md phdng (a) vl m^ng nhidt djiaphln Ihu sdng chfi V (b) - Phuong trinh can bang nang lupng ciia tam thu nhi^t phlng: S2 = h2a2-Tfl)+h^,Cr3-Ti)+UbCr2-T^ (4) Vdi hue xa mat trdi m l tim hap tiiu nhan dupe tinh bing: S2 = T;OC2I (5) - Tai mit Ti, vdi phan thu phlng Hd sd truyen nhiet ddi luu gid tren be mat tim kinh dupe tmh theo cdng thiic McAdams (1954), vdi VII v^n tdc gid: h^ = 5,7 + 3,8v (9) Hd sd truyen nhiet biic x^ giira tim kinh va blu trdi quy vd nhiet dd mdi trudng ed thd vidt II (Karim etal., 2013): b Phuong trinh can bang nMng luong cua /ism thu chd V h„=OE,(T,-.T,)(T,^-.T;^)fc^(10) - Phuong trinh cin bang nang lupng ciia tam thu nhidt sdng chu V: Khi cae he sd truydn nhiet h^ vl h,^ da cd, he sd S2 = haCTs - T ^ + hatTg - Tfj) + h^^O^^ - T3) + tdn thIt nhiet mat tren tam kinh dupe tinh la: h^ia2-T,)(6) UT = h,-Hh^(ll) - Phuong trinh can bang nang lupng cua ddng He so truyen nhiet biic x^ giiia tara kinh phii vl d kenh dudi, phin b6 thu sdng chii V: tim hap thu diroe tinh bang: haaa-Te) ^ h ^ a e - T a ) •^Q2(7) - Phuong trinh can bang nang luong cua mat diy, phin bp thu sdng chu V h,(Tiz-T0 -Hh^a2-T3) = U ^ a a - T ^ (8) I - Biic X9 mat trdi (W/m^; hi, hi, hg, hi - Cic he sd huydn nhiet ddi luu, (W/mllO; hr2i - Hd sd truydn nhiet btrc xa td- tim thu nhiet den tam kinh (W/m^.IO; hr2j -He sd truydn nhiet biic xa tu tam thu nhiet ddntlmdly(W/m2.K); Si vl 83 - Biic xa mat trdi tim kinh hap thu va tam hap thy hip thu dupe (W/m^; Ta - Nhiet dp khdng mdi trudng (K); Ti, Tg, T3 - Nhiet dd tiung binh cua bd mat tim k i n h , t ^ hap thu, tim diy (K); He so truyen nhiet ddi luu giiia ddng vl tam kinh phu dupe xac dinh bing phuong trinh Hollands vIShewen (199i): h,=Nu,,^(13) Trong dd, dudng kinh thuy luc cua ddng Dh dugc tinh nhu sau: D,=-5^ (14) ' H+W H - Khoang each tir tam kinh d^n tam thu nhi^t ph4ng (m) Sd Nusselt duoc iroc tinh theo Kays va Crawford (1980): NONG NGHIEP VA PHAT TRIEN NONG THON - KY - THANG 12/2015 45 KHOA HOC CdNG N G H £ Nui2 = 0,0158Re''-*' (15) Trong dd Re II sd Reynolds vl dupe tinh theo cdng thiic: Ndu Re = p v , ^ ( ) 10* Ndu 2800 Re H Nu,, = 1,9.10' R e ' " + 2 - i (24) L, 10