NGHIEN cufu-TRAOD6I M PHONG SO THIET Bj CHU'NG CAT NU^O^C Sl> DUNG NANG LU'gNG MATTRO^I DANG SINGLE BASIN KET HO? ONG THUY TINH CHAN KHONG NUMERICAL MODELLING OF A SINGLE BASIN SOLAR STILL COUPLE WITH EVACUATED GLASS TUBES Hoang Van Viet', Nguyen The Bao^ 'Cdng ty TNHH Le Phong ^Vien Phat tridn Nang lugng Bdn vung ISED Bdi bdo trinh bdy thuc hien mo phong so dua fren phdn tich nhiit & thiit bi chung cdt nu&c su dung ndng lugrng mgt tr&i dgng Single Basin, kit hap ong thuy tinh chdn khong Viic mo phong giup du dodn nhiet mat ngodi ciia Hnh phu (T J, nucrc cdn chung cdt (T^, cUng nhu hiiu sudt (T)^) vd sdn luong (m^J md thiet bi dgt duac Kit qud sau mo phong se duoc kiem chieng bdng mo hinh thuc te thong qua thuc nghiem tgi dieu kien TP Ho Chi Minh nhieng ngdy ndng thdng 4/2015 V&i dien tich 0,6 m^ (dien tich boc hai) kit hap ong thuy tinh chdn khong, thiit bi cho sdn luong cao nhdt sdu l&p nu&c cdn chung cdt Id 0,01 m (6 lit), nu&c nggt 0,02 m (17,Slit) Sdn luang nu&c chieng cdt qua mo phong dgt 6,65 kg/m^ (tie 7-I7h); Trong thiec nghiem cho 5,86 kg/m^ (tic 7-17h), img v&i hue xg trung binh 516 W/m^ Hiiu sudt trung binh ciia thiet bi dgt 43,76 %, nhiet nu&c cdn chung cdt l&n nhdt 90,82°C Tir Idida: Chung cdt nu&c su dung ndng lugmg mat tr&i ABSTRACT This paper presents numerical modelling based on the thermal analysis of a single basin solar still couple with evacuated glass tubes Modelling performance has been predicted theoretically in terms of brackish water (T^J, outside glass cover temperatures (T J, energy efficiency (TJ^) and output (m) Result of modelling has been confirmed by experiment in the sunny days in april in Ho Chi Minh city With an area of 0,6 m^ (evaporating area) couple with evacuated glass tubes, equipment has the highest output when the brackish water depth is 0,01 m (6 liters) and the fresh water is 0,02 m (17,5 liters) Production of distilled water by modelling reached 6,65 kg/m^ (from 7am to pm) while one by experiment was 5,86 kg / m^ (from 7am to pm) to the average radiation 516 W/rr^ Average energy efficiency was 43,77 %, maximum brackish water temperature reached 90.82 "C Keywords: Numerical modelling of solar still; Evacuated glass tubes, performace of solar still ^ ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd nam 2015 www.cokhivietnam.vn NGHIEN cufu-TRAOD6| 2.2 Ket cau cua thiet bi DAT VAN DE Lam dung ngudn nang lugng hda thach keo theo thidn tai, d nhidm moi trudng, can kiet ngudn nudc sach dang thuc su de dpa cupc song ngudi Van dd tiet kiem nang lugng di cung vdi bao vd mdi trudng dang dugc the gidi tich cue khuydn khich ung hp Viec tao nhihig thiet hi chung cat nudc sir dung ngudn nang Iugng sach va cd trii lugng rat ldn nhu mat trdi tao hieu iing tich cue vdi moi trudng, cd y nghla to ldn vdi nhung ngudi dan dang sinh sdng d nhiing vdng midn thieu nudc sach hay ngudn nudc bi nhidm, dac bidt la nhirng quoc gia cd vung lanh thd keo dai trdn bien nhu Viet Nam Trong bai bao nay, tac gia thuc hien viec md phdng sd dua trdn cac cdng thiic truydn nhidt, thuat toan va phuong trinh can bdng nSng lugng tai cac phdn ciia thidt bi chung cit nudc sii dung NLMT dang Single Basin kdt hpp OTTCK dd du doan nhidt dp cua nudc, Hinh 2: Mo hinh thiit bi thtec nghiem nhidt dp tam phu, ciing nhu san lugng va hipu suit cua thidt bi theo muc nudc dd xuat Tu dd danh gia dugc anh hudng cua dp sdu ldp nudc Thiet bi la su kdt hgp cua cac phin sau; hay khdi lugng nudc cdn chung cit ddn hidu qua cua thidt bi Kdt qua md phdng dugc so - dng thuy tinh chan khdng (OTTCK) sanh vdi kdt qua thuc nghiem dd kidm chiing cua hang Megasun loai dai I - 1,8 m, dudng kfnh chuang trinh md phdng ngoai d^ = 58 mm, dudng kinh d^ = 47 mm, MOTATHIETBI 1.1 Sff nguyen ly cua thiet hi - Mang chung cit dugc lam bdng inox 304 day mm, he sd dan nhidt k^ = 16,2w/ m^c, cd dien tich bdc hai A^ ^ A^ - 0,6 ml Kinh phu day 1^ - 0.004m, cd he sd ddn nhiet Ag = 0,7SWI m°C [4] Mang chung cdt dupc hoc each nhidt ddy 1^ - 0,05m bdi vdt lieu cd he s6 dan nhiet k^ = 0,036^ / m^C Hinh I: Sodd nguyin ly thiit bi - Tam truydn nhidt (Basin liner) lam bang inox 304 ddy 1^^ - 0,4mm, cd dien tich A^ = 0,6 m^ dugc son den dd hip thu NLMT ISSN 0866 - 7056 TAPCHiCOKHiVl£TNAM.s6 6nam2015 www.cokhivietnam.vn NGHIEN cufu-TRAO Ddl MO PHONG SO THIET BI ngoai cua kinh phu [4] Cac dieu kidn dd thidt lap chuang trinh md phdng: - Thidt bi khong bi tdn thit hoi (kin hoan toan) - Nhiet dung rieng cua kinh, tdm truydn nhidt va phan day inox cua mang chung cdt dupc bdqua - Gradient nhiet dp khdng hien dien theo dd sau Clia muc nudc _ h.-T,.+h„„_T (2) Tu (1) va (2) ta cd nhidt dp mat cua tam phu: aJ(t).A^ +h^.A^.T^+h,„.AT - Muc nudc thidt bi tri khdng ddi - Nhiet dp nudc dng TTCK la nhiet 3.3 Phuffng trinh can bSng nhiet tai tim dp trung binh cua nhidt dp nudc vao varakhdi ong truyin nhiet (Basin liner) - Gia tri ban dau cua nhiet dp nudc bidn va bd mat kinh phii dugc diing dd xac dinh he sd truydn nhidt bdng ddi luu (h^^), biic xa (h^) va bdc hai (h^^) tai thdi diem ban diu - Bd qua ton thdt nhidt ben vach cua thidt bi Trong dd: Ongc4pnv»c vdi x; dp sdu cua nudc (m) [7] QlH Q- - - ^ mlnirtnnlaA -r^ i-^ - -/ KMi[Mi — l*pM04r> ''^ ^^ ^ OngTTCX Hinh 3: Dong nhiit thief bi Bang 4.1: Subien thien cua fi theo he so suy gidm n cua nu&c i 3.1 Phuong trinh can bSng nhiet tai he mat cua lunh phu [4] a,JXl).A^+h,,.A„.{T„ -T^) = h^.A^.{T^ -T^) 3.2 Phmmg trinh cSn bang nhiet cho he mat (1) Pj 0,237 0,193 0,167 0,179 0,224 "jCm') 0,032 0,45 3,0 35,0 255,0 ISSN 0866 - 7056 TAP CHi CO KHi VIET NAM, Sd nam 2015 www.cokhivietnam.vn NGHIEN cufu-TRAO ePi 3.4, Phiromg trinh can b^ng nhi^t cho khoi niro^c bien a.-^.-'MA *AA.,-„-in dT„ - r ^ ) =M„ c, .-^+h„.A,.(T^ -T^) (5) Trong dd: a^ =a^.c,„ 3.5 Phuffng trinh can biing ntuet cho kh6i nudc ngot bhn chimg cit A (T —T) A^>V(r^-r^) = AA., (?;.-7;)+ "'y fiT •' +M„.c,.4^ (6) Trongdo: A^^., = /i^,,_, =5,7 + 2,8.v [4] 3.6 Phu-olig trinh can bSng nhi|t cho ldi6i nird'c ngot OTTCK 4'V,/,(0'7,-a'4A',(r„-7:) = M „ c „ ^ + i V > c „ ( r „ - J ' ^ ) (7) - Lira lugtng nuac khoi OTTCK theo nguyen ly ddi luu tu nhien ducrc tinh theo [4, 6]: th = 0,OAixd,n^ A,c,f (kg Is) \d, Tir phuotig trinh (5), (6), (7), ta co he phuong trinh vi phan tuySn tinh cSp khong thuk nhit: ~ + '',T„+b,T^+c,T„=f(l) ~+''2T^+b,T^+c,T,^=f(,) (8a) (8b) dT -^+• li:" upi: Mil liTDC pbinmii •• 90 M V jg * .—*—TTW ^-S^-Sis^l^ y ^ ^ ^ " ^ * ' -^^^^ ,=s»*^^ S lo, 10 OT-00 08:00 0»00 IftOO 1) K nirAr ilta Ibyc ••Ufa nt pbiK cw Iblct b| i PAI m 1: «( ^ - -~~^ " >^^^ :::i ^ -'^ >5^ - « j ^ ^ K £ T LUAN Nhu vdy, thdng qud vide md phdng sd dua tren kdt cau cd san cua thidt hi, chung ta cd the du bao dugc nhidt dp tai cac didm dac trung, san lugng nudc va hidu suat ciia thiet bi, tii dd chpn muc nudc hoat dpng tdt nhdt cho thidt bi (PAI) Vide mo phdng giup chung ta cd cai nhin tdng quan vd thidt bi Kdt qua mo phdng kha chinh xac, sai ldch 11.85% Cac cdng thuc lidn quan hoan toan cd the tin cdy dd lam tidn dd cho nhimg bai toan md phdng va tinh toan thiet kd d nhiing dang thidt bi chung cat khac.*J* Ngay nhan bai: 14/4/2015 Ngay phan bidn: 18/6/2015 ^Ti lit::i ^»*==*^ " ^^ I^I lI l III 1 Il Ii Ii i