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IM!r»Mit*Mc6NG NGHE DANH GlA HIEU QUA THU N A N G Ll/gNG MAT TRGll CUA ONG NHIET TRONG TRUCfNG CHAN KHONG SUf DUNG MOI CHAT ETHANOL EVALUATING THE EFFECTIVENESS ABOUT SOLAR ENERGY COLLECTION OF VACUUM THERMOSYPHONS USING ETHANOL SOLVENT D i n h Xuan Thanh, Vu Van Minh, Cu Huy Thanh Tom t i t Bai bao trinh bay nghien ciJu ling dung ong nhiet trUcing chan khong sil dung moi chat Ethanol de thu nang lumtg mat trdi Ket qua cho thay, bg thu nang lugng mat trili de dun mdc nong thi co hieu su3t nhiet kha cao khoang 62%, thdi gian dun nudc nong giam, khong co hien tuong cau b^n ong thCiy tinh, nhiet luong cOa nUdc nong thiing khong b\ mat liic trdi ram mat nhudot v6i bg thu nang lUOng kieu cu Iii khda: ong nhiet, chan khong, nang lu'ong, mat trcfi, dun nu'dc nong Abstract This paper presents the results of research and application of vacuum thermosyphons containing Ethanol solvent used to collect solar energy The study results show that when using vacuum thermosyphons for solar collectors to heating water, the high thermal efficiency of about 62%, heating time is reduced, the glass pipe is not dirty and there is not loss of heat of water in cool days Keywords: thermosyphons, vacuum, energy, solar, water heater TS.fimh Xuan Thanh -TrUetng Dai hoe Cong nghiep Hii Noi ThS VQ Van M[nh -TriTflng Cao dang nghe Cong nghiep Ha Noi PGS.TS CiJ Huy Thanh - Hoc vien Ky thuat Quan sU Email, cuhuythanh@yahoo.com 1.0ATVANDE Ong nhiet diToc sang ehe tCf rat lau nhifng viee nghien eCTu Crng dyng no mcifi ehi phat trien manh thdi gian gan day Ong nhiet trpng tradng la mot phan tCr truyen nhiet eo nhieu tinh nang tot hOn so vdi cac phan tCr truyen nhiet truyen thong nhU: gon, nhe, cau true don gian, d^ bao difdng, giam ap suat khi, an toan van hanh cao, de lap dat, Hien nay, no daoc diing Ngaynhanbai: 15/01/2014 Ngay ch^p nhan dang: 21/03/2014 eae thiet bj thu hoi nhiet tai cac nha may cong nghiep, tan dung nhiet khithai eua nha may Nguyen ly cua qua trinh truyen nhiet co ban giong d cac ioai ong nhiet, nhUng eong suat nhiet phy thuoc vao eau tao va dieu kien lam viee cua ong nhiet Bang each thay doi cau true cua ong, laong va loai moi ehat nap ong cd the che tao cac loai ong nhiet khac 381 TapchiKHOAHOC&CONGNGHE So OViet Nam, ong nhiet trUdng da bat dau dUoe nghien cCTu sCf cJung lam thiet bj thu hoi nhiet nham tiet kiem nang laong va bao ve moi tn/dng, nhang ket qua nghien cii'u ve ong nhiet trpng trUcfng chan khong co moi ehat Ethanol thi ehUa dUdc cdng bo.Vivay, nghien eiJu thiet ke, che tao va danh gia hieu qua trao doi nhiet cua bo thu nang lypng mat trdi dung dng nhiet trUdng chan khdng sd dyng m6i chat Ethanol bd dun nUde ndng nham nang cao dp tin cay va giam chi phi la hadng nghien cCru mdi, dap i^ng yeu eau thac t i i n LlTA CHON K T CAU CCPA 6NG N H I E T T R O N G T R U O N G C H A N KHONG Bd phan thu nang jyong mat trdi cd hai loai co ban la tam phang va tap trung, vdi cau tao kha phong phu, che tao bang nhieu loai vat lieu khae nhau, cac be mat ha'p thy ehpn Ipc eung r^t da dang Tren cd sd phan tich v l dac diem ket cau, yeu eau eCia thiet bi, dieu kien eong nghe va vat tasSneddegi^ni gia cua san pham; da li/a chpn phaong an sCr dung bd thu nang luong mat trdi kieu tam hut ehan khdng (l^e mat dng nhiet nhSn), day la mot bien the eua bp thu nang lUpng dang tam phang, cd hieu qua rat eao, cao Ni/dc ^ ^ f-or NUdc -f l-i^hap ihu ndng Img biic xg; 2- 6ng thuy tinb chdn khdng (phdn nhdn nhiet - phdn sdi); 3- Thiing chdo nudc, 4- Nudc ndng sddung 5- 6ng ddng (phdn tod nhiet hoac phdn ngi/ng); 6- Gid dd; 7- Chdt Idng nap dng nhiet, fy - Nhiet dg khong bin ngoai; t^^ - Nhiet be mat hdp thu; q^- Nbiet bdcxa ddp vdo vd ngoai; q^- Hhiet bdcxo tam hop thu nhdn; q^ - Nbiet too mdi trudng; q - Nhiet cop cho dng nhiet Hinh Cau tao bo thu ong nhiet trgng trUcing chan khong shon rat nhieu so vdi loai tam phcing thdng thudng khae Dac la ys^C, khoang nhiet ibiet, cd the sCr dung d nhCfng vung tt nang hoac cd nhiet dp dd lam viec O-HISCC, mgoai trdi khdng cao Hieu qua cua bd thu nang luong hau phii hpp vdi ong nhiet nhu it phu thupc vao toe dp gid d mdi tradng xung quanh bang dong) Vdi pham Bd thu nang laong daoc eau tao t a nhieu dng chan khdng vi nhiet dd hoi ighep song song dat tren ciing mdt tam phang nam nghieng, dng nhiet khdng eao, d '•-•V' •gdc nghieng cua tam p h i n g ve co ban phu thude vao npi lap ap suat khiquyen nhiet 'Mo dat, lien quan tdi gdc tryc xa cua tia nang mat trdi Do tiet dp sdi ciia Ethanol nho jdien ciia moi dng deu cd dang hinh trdn nen kha nang nhan hon cua H^O, nen ibac xa mat trdi cua dng loai tdt hon rat nhieu so vdi cac dng ed nhiet dp nhd idng dang tam phang thdng thadng va vao bat ca luc nao hon lOO^C Ethanol se cac tia bae xa mat trdi cOng co the den thang gdc vdi be mat cd ap suat khdng thap ngoai ciia cac ong nhu vdi HjO, dam bao Cciu tao cua mot dng nhiet trpng trudng dang ehan khdng xam nhap khdng duoc trinh bay nhu tren hinh T Vd boc hinh tru bang vao ben dng [1] thu;;* tinh cd dang ong nghiem, gom hai Idp: ben ngoai va Khi nhan nhiet bdc ben trong, d giCa hai Idp la chan khong Ca hai Idp deu xa chat Idng se sdi Hinh So phan bo nhiet trd cua ong nhiet lam bang thuy tinh Borosilicate, Idp ben ngoai hoan toan bien hoi ehuyen suot, cdn Idp ben dupc san ehat hap thy ehpn dpng len tren toa nhiet Ipc d be mat dudng kfnh Idn hon (be mat tiep xuc vdi ehan cho nude thiing chi^a va se ngUng ty lai rdi quay ve khdng) Ben vd bpc bang thuy tinh hut chan khong phan dng thuy tmh, Phan ngUng tu d phia tren lam b^ng cho ap suat tuyet doi khoang 5.10-^ Pa Day la phan nhan ddng de de dang tda nhiet cho nudc thung nhiet bii'c xa mat trdi cua ong nhiet (goi la phan sdi eua dng) Cong suat ciia mdt dng nhiet tradng dape xac dinh ::hinh nhd dp chan khdng vd bpc hinh tru bang thuy theo cdng thdc [1,6]: At tinh ma cac ton that nhiet doi lau va dan nhiet giam di Jang ke R R v , + R + Rh + f^n + Rv.n + Rw (1) -r Mdi chat sCf dung dng nhiet la Ethanol, phu hop vdi feu cau lam viec va ket cau cua thiet bi (nhiet dp sdi d at day R -Tong nhiet trd (K/W) [hinh 2); At - Hieu so nhiet dp gida nhiet dp tam hap thu t va So TapdiiKH0AH0C&C0NGNGHr39 EEEEElcQNG NGML hOngnhiet, 2-Ihdng chda nudc, 3-Gid dd; 4-Tdm phdn xa Hinh Cau tao bo thu nang lUOng mat trdi ong nhiet ehan khdng nhiet nudc thiing t^; R^^ - Nhiet trd dan nhiet qua vach ong phan sdi (phan thuy tinh); R^-Nhiettrdsdiehatldng{Ethanol ) ong nhiet d phan sdi; R|^ - Nhiet trd hoi ehuyen dpng ta vung sdi (dng thuy tinh) tdi viing ngUng (dng ddng) Gia tri nhiet trd rat nhd ta thudng bd qua R|_ = 0; R^ - Nhiet trd qua trinh ngUng hoi dng nhiet d phan ngUng (phan dng b^ng dong); R^^ - Nhiet trd dan nhiet qua vach dng phan ngUng (phan ong ddng); R^^ - Nhiet trd ddi luu cua nude thiing vdi be mat ngoai phan ong ddng cua ong nhiet Ky hieu Rg= R^^ + R^^ + R^ la tdng nhiet trd ngoai va R - R^ + R^ la tong nhiet trd va bd qua nhiet trd eiia hoi R^ = 0, ta cd: R = R^ + R, Q'=- Bd thu nang lupng dun nadc ndng sCf dung 10 dng nhiet trUdng chan khdng mdi ehat Ethanol cd eau tao nhutren hinh (2) (3) Gpi Q^- Cdng suat nhiet ben cua dng nhiet, ta cd: I-Ddu ngp moi chdt; 2- 6ng ddng $22; 3- Khdp ndi; 4- Ong thuy tmh chdn khdng Hinh Cau tao cua dng nhiet Vd thung nude lam bang Inox day 2mm, ben ngoai bpc mdt Idp cac^ nhiet day 50mm, hinh try, dUdng kinh 470mm, dadng kinh ngoai Idp each nhiet la 570mm 6r\g nhiet gom hai phan: Phan phia dudi nhan nhiet bufc xa mat trdi (phan sdi), la ong thuy tinh chan khdng ben cd tam hap thy nang lupng mat trdi, phan tren la phan tda nhiet (phan ngUng) eho nadc thiing la ong bang dong Mdi chat nap Ethanol (95%), bang thue nghiem da laa chpn di/ot luong nap phu hpp la kholing 30% th^ tieh eua phan dng thiiy tinh -De noi phan ong bang dong vdi phan ong thfiy tinh chan khdng, diing mdt khdp nS bang cao su va keo dan (hinh 4) Tam phan xa ia tam bSng Inox daj' mm, dat phia dUdi phan dng thiiy tinh ehan khdng, vifa de dd cac ong vifa de ph^n xa lai tia bifc xa mat trdi vao 6ng de tang lUpng nhiet hap thu - Do nhiet dp be mat ngoai ong nhiet va nhiet dp khdng ngoai trcd: So lap dat dau dUpc trinh bay tren hinh Diing cap nhi§t nhiet b^r ngoai phan thiiy tinh va phan ong dong, theo chu vi dng va chieu dai dng, sau lay trung binh duac gia tri nhiet ben ngoai phan sdi t^^, va nhiet dp ben ngoai phan ngang t^^ d 3ay, nhiet dd ben ngoai phan dng dong^ coi bang nhiet dp ben t, (t,,^ ='^, vi ddng ed he so dan nhiet idn v^ chieu dai eua dng nhd) Nhiet dd ben ngoai phan dng thOy tinh t^^ chinh la nhi§td6 mat ngoai kinh phii dng thiiy tinh chSri dau do(tnn) d day, t^, t^ - nhiet dp be mat ben phan sdi va phan ngung eiia dng nhiet d che dn dinh: Q' = Q 100 X O A N H GlA HIEU QUA TRAO DOI NHliTClJAONGNHieTTRpNGTRU'ONG 3.1 Xac dinh cong suat va hieu suat bo thu nang lUcrng /- Bdu be mat phdn ong ddng; 2- Bdu be mat phdn dng nhiet bong thuy tinh chdn khong Hinh So vi tri dat dau cam bien nhiet cDa ong nhiet 401 TapdiiKHOAHOC&CONG NGHE S dau go(t- = t.) SCIENCETECHNOLOGYl cd cong suat ciia mpt ong nhiet: Q' = 783/10 = 78,3W Nhiet lapng bi^c xa mat trdi dap vao tam hap thy cua dng nhiet chan khdng giay duoe xac dmh theo cdng thufc Q',, = F \ * q , , (8) t^ft^- Cdc vj tri ddt ddu nhiet nudc binh Hinh So vi tri dat dau cam bien nhiet ciia binh nudc khdng t^ (t^ = tJ Nhiet dp khdng nhan dape gid: ingoai trdi 1,^^ dupc bang nhiet ke Q*„ = G^ C^ At^ (5) -Do nhiet dp cua nudc thiing: day: G^- Lapng nUde thung ,Diing hai cap nhiet dat d vi tri gida (kg); •thiing (hinh 6), roi lay trung binh dUOc O Nhiet dung rieng ciia nudc d iinhiet dp nUdc thiing mdt thdi nhiet trung binh t^ = 45°C, C^- 4,174 rdiem la t^ kJ/kg.K [4]; I Tien hanh 15 ngay, mdi At^- Gia tn nhiet dp nUde tang trung lan, thdi gian bat dau t a binh gid, At^ = 7,5''C (theo bang ;10 gid, khoang each moi lan la 1); gid, nhiet dp nadc ban dau vao thiing C -Thdi gian do, gid; i,la20''C Ket qua trung binh 15 Tacd: Q*„ - 4,174.7,5- 2818 kJ/h (bang 1) LUOng nhiet ma nUde thiing day: At^- Gia trj nhiet dp nUdc nhan dUOc giay: Q^ = Q ^ / ^ (6) ,tang trung binh gid Taed:Q„ = 8 V 3600-783W Ket qua cho thay, nhiet dp nUdc Nhiet luong eua mdt dng nhiet cua thung tang trung binh mdt cung cap cho nUdc thung gid khoang 7,5°C , - Xac dinh cdng suat va hieu suat bp giay (W): Q' - Q / n (7) d day: n - sd ong nhiet, vdi n = 10; ta thu nang laong: LUOng nhiet ma nadc thiing Being Ket qua nhiet dp bang thifc nghiem l i n U t Thdi diem lOh llh 12h 13h Mh 15h 16li u-c 29,9 32,0 U t t^t 35,0 20,0 Mn,t 34,0 35,0 35,5 26,8 40,0 42,0 39,0 33,8 6,8 7,0 42,0 45,0 48,0 44,5 10,7 42,0 46,0 53,0 50,0 40,0 46,0 60,0 57,5 36,0 44,0 67,0 65,0 5,5 7,5 7,5 Bang 2, Nliiet t o [«(& nong thung coa thlet bi don nuSc sii dung ong nhiet trgng truing moi cha't Ethanoi (t^^) v « thiet bi ciia hang SEiLAR ( t ^ J Lin Tlidi diem t,-SEItM,°C tu,'C t.-,i,"C Loht)an,°C 9h 12h 29,9 28,0 28,0 35,5 40,6 49,6 9,0 13h 35,6 45,6 60,0 14,4 14h 18h 38,1 65,0 81,0 16,0 35,0 73,0 85,0 12,0 day: q^_ - Nhiet bdc xa dap vao tam hap thu, (W/m^); F^^ - Dien tich mat ngoai phan sdi ciia ong, m^• Theo Liu-Jordan, nhiet lapng bdc xa dap vao tam hap thu gom phan: true xa, khueeh tan, phan xa cua mat dat; dupe xac dinh theo b^ng cdng thifc [5]: f t , = q R, + q'^ (q',+q'K (1 + C ^ ) (9) (l+cos^ day: q', - Ddng biic xa trye xa tdi mat nam ngang, (W/m^); q'^ - Ddng bire xa khueeh tan mat nam ngang, (W/m^); p - He sd phan xa cua mat dat; R, He sd true xa; P - Gdc nghieng cCia be mat khao sat so vdi mat nSm ngang; Neu chpn gdc lech cua mat trdi = 23,3"; goe phuong vi cua be mat khao sat Y = 0° {hinh chieu cua phap tuyen triing vdi phupng nam); vi dp vi tri be mat khao sat ^ = 20°; gdc gid cua mat trdi LiJ = -30°; gdc nghieng cua be mat khao sat so vdi mat nam ngang p = 30° Ta cd [5]: n + cosSO") = 852.0,81-1-642 F\=n.d^.L- 3,14.0,033.1,6=0,166 m'; Q'^„ = 0,166.762-126,3W; Hieu suat cua bd thu nang lUpng mat trdi: n= Q'/Q^^,, - 78,3/126,3 = 62% 3.2 Danh gia tinh nang cDa thlet bj thu nang luomg De danh gia tfnh nang lam viec ciia thiet bi thu nang luong mat trdi dun nUde ndng sif dung ong nhiet tradng chan khdng vdi mdi chat Ethanol, So • Tap diiKH0AHpC&CCNGNGH^41 •EI5HIEiC6NG_NGHE da che tao thiet bi sif dyng 18 ong nhiet dng nhiet trpng trudng chan khdng trpng trUdng (dudng kinh 58mm, chieu vdi mdi chat Ethanol cd thiet ke don dai 1800mm) sif dyng mdi chat Ethanol, gian, sir dyng cae thiet h\ s i n cd tren [1] Bill HSi, Tran Van Vang, 6ng nhiitvJ:iJiij so sanh vdi thiet bi tUong dUOng cua thi tradng, de dang lap dat, dam bao dung cua ong nhiet, NXB Bach khoa Ha Npi, (200B) hang SEILAR (ma sd SS158/18, dung gia thanh, cdng suat cua ong nhiet tieh thiing chira nudc la 216lit) Ket qua khoang 78,3 W, hieu suat cua bd thu nhiet dp d cac thdi diem khae nang laong dat khoang 62%, thdi gian duoc trinh bay tren bang dun nudc giam so vdi bd thu kieu cu, Nhiet ciia nadc ndng thung it Ketquaehothay, nhiet dd nude thiing ciia thiet bj dun nude sCf dyng ong bj tdn that liic trdi ram mat, ong nhiet nhiet trUdng chan khdng vdi mdi trpng trudng lam viec nhU mdt didt T A I L I C U THAM KHAO [2] Bill Hai, Tinh toan thiet ke thiet bi t r a o i nhiet, NXB Giao thdng van tai Ha Ngi, (2002) [3] Bill Hai, Duang fitfc Hong, Ha Manh Itia, Thiet bl trao dm nhiet NXB Khoa hoc va liytiiual (2001) [4] Bang Quoc Phii, Tran The Son, Trln Van Ptifi, Truyen nhiet, NXB Giao due, (1999) chat Ethanol ludn luon eao hon so vdi nhiet mdt chieu, nhiet nUdc [5] Le Chi Hiep, May lanh hap thu kytfiuai thiet bl cua hang SEILAR, vao thdi diem thimg chda Idn hon nhiet d d ciia dieu hoa khongkhi, NXB Dai hpc Quoc gia TP HDOU' cudi budi chieu cao hon tdi 12''C, khang phan dng nhiet thuy tinh thi dng nhiet Minh, (2004) dmh tinh nang vupt trdi cua thiet bi khdng hoat dpng K^T LUAN [6] iVldi chat Ethanol sif dyng la phii ong Faghri, Heat pipe science mi nhiet hpp vdi yeu eau lam viec va ket cau cua [7] Caivin, Silvertein, Design and technologyof trpng tradng chan khdng sif dung mdi thiet bi, khdng xay hien tUOng nudc Heat pipes for cooling and heat Exchange, Taylor i chat Ethanol bd thu nang lUOng sinh hoat ddng cau can ben dng Francis, (1992) mat trdi dedun nudc ndng la giai phap nha vdi kieu cu, khdng bi nUde xam kha thi, gdp phan kh^e phue dUOc cac nhap vao ben cua ong nhiet Nghien ciiu sCf dung Amir Technology, TaylorS Francis, (1995) nhupc diem ciia bd dun nUdc ndng hien dang SLf dyng d Viet Nam [8] Jon A Duff, William A Beckman, Soli Engineering of Thermal Pmcesses, John Wtleyfi Sons, lnc.715p,(1980) Phin bien khoa hoc: TS Bill Manh Tii Bp thu nang lapng mat trdi sif dung [9] J.Andrew, A Akbarzadeh, I Saucius, HHI pipe Technology, Pergamon, (1977) ^•mm^ NGHIEM THU DETJ^I NCKH nhom nghien ciJu da: He thong hoa cac van de ly luan chung ve to chiic cong tac ke toan, nhSng van de co ban ve dao tao ke toan ao Qua dd, xay dung te Chi^u 18/3/2014, Hpi dong khoa hpc da td chilc nghiem thu 02 de tai mo hinh phong ke loan mo phong, bo tai lieu thuc hanh ke toan thu cong, thiJc "Nghien ciht mile hai long cua sinh vien khoi nganh Kinh te tai hanh ke toan tren may, bien soan bo bai giang ve ky nang mem cho ngudi Iam trUdng Dai hoc Cong nghiep Ha NSi" va de tai "Nghien culu xay diAig mo ke toan; xay difng duac 35 tinh huong thifc te phuc vu dao tao ky nang cilng hinh va tai lieu thiic hanh ke toan ao die sinh vien chuyen nganh Ke va ky nang mem cho ngucii hpc Bong thoi, tac gia da tien hanh dao tao ftiJ toan - Trirotng Dai hoc Cong nghiep Ka Noi" nghiem tai phong thifc hanh ciia khoa va tham y kien ciia ngu6i hpc, Ket qua cho thay ngUOi hoc danh gia rat cao tinh tinh cUc va ling dung ciia moiiiiih -Thong qua kh^o satthutte va nghien ciJu mo hinh lythuyS ve cac yeu to^nh Hai de tai ^uoc Hoi ddng khoa hoc danh gia cao, cd y nghia thietthi/c thift hu'dng den mile dp hai long cua sinh vien (SV) WJOI kinh te tai trudng QH Cong te dao tao va dupc nghiem thu xep loai Xuat sac nghiep Ha Noi, TS Bang Ngoc Hiing cung nhom tac giJ khoa Ke toan - Kiem toan va khoa QuSn ly kinh doanh da hoan de tai "Nghien cvfu mdcdg hdi Idng cua sinh vien khoi nganh Kinh te tgi trddng Bgi hgc Cong nghi^ Ha Ndr Qua nghien ciJti, nhom tac gia da xac dinh difflc yeu to chinh co tac dpng den sir hai long cua SV: Nang lire giang vien, chifong trinh dao tao; Nang lire nhin vien phue vu; Phong hpc vh may moc thiet bi; Giao trinh phuc vu dao tao; Thif vien phuc vu dio tao; To chiic quin ly, danh gia dao tao va Kly dung thang sifhai long cua sinh vienvechatli/tmgdaotaode tien hanh dieu tra Tif do, nhom tac gia dira nhifng khuyen nghi nhSm nang cao chat luong Ska tao SV khoi nganh Kinh te tai trifiing DHCNHN • f)e tai "Nghien cdu xay dying mo hinh va tai liia thdc hdnh ketodn ao cbo sinh viin chuyen nganh Ketoan - Trddng Bgi hgc C6ng nghiep Ha Ngi" TS Nguyen Thi Hong Nga chu nhiem Tren ccfsd nghien cUu i^ thuyet va viec ling dung trien khai tai mpt so trifcing dai hpc, trung tam dao tao ke toan, i Tap Chi KHOA HOC&CONG N G H E - S ... (phan thuy tinh); R^-Nhiettrdsdiehatldng {Ethanol ) ong nhiet d phan sdi; R|^ - Nhiet trd hoi ehuyen dpng ta vung sdi (dng thuy tinh) tdi viing ngUng (dng ddng) Gia tri nhiet trd rat nhd ta thudng... tao ke toan ao Qua dd, xay dung te Chi^u 18/3/2014, Hpi dong khoa hpc da td chilc nghiem thu 02 de tai mo hinh phong ke loan mo phong, bo tai lieu thuc hanh ke toan thu cong, thiJc "Nghien ciht... vd bpc bang thuy tinh hut chan khong phan dng thuy tmh, Phan ngUng tu d phia tren lam b^ng cho ap suat tuyet doi khoang 5.10-^ Pa Day la phan nhan ddng de de dang tda nhiet cho nudc thung nhiet
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