NGHIEN CLUU - TRAO OPl
LY THUYET TINH TOAN VA THU'C NGHIEM THIET B\ CHU'NG CAT N U d c Sir DUNG NANG LUONG MAT TROfJ DANG SINGLE BASIN
KET HOP ONG THUY TINH CHAN KHONG
CACULATION THEORY AND EXPERIMENT OF A SINGLE BASIN SOLAR STILL COUPLE WITH EVACUATED GLASS TUBES
Hoang Van Vilt", Le Xuan Phong', Nguyin Thanh Dung', Tran Xuan An', NguySn ThS Bao'
'Cong ty TNHH Le Phong 'Trucmg Cao ding Cong Thucmg TP. H5 Chi Minh
'Vien Phat trien Nang lugng Ben virng ISED TOM TAT
Ndng lugng mat tr&i Id nguon ndng lugng sgch vd CO trit lugng rdi l&n, vi vgy viec dua cac Ihiel bi vdo de khai thdc nguon ndng lu&ng ndy co y nghia l&n, ddc biel, vol nhimg quoc gig co so gia ndng vd buc xg lot nhu Viel Nam. Cdc thiet bi chung cdt nu&c Iruyen thong su dung ndng lugng mat Ir&i & nu&c ta con dan gidn vd sdn lugng chug cao. De ndng cao sdn lugng nu&c chung cdl, nhom nghien cuu da xdy dung len thiet bi chimg cdt nu&c sit dung ndng lugng mat trai v&i dien lich 0,6 m'' (dien lich boc hcd) kel hgp 8 ong thuy tinh chdn khong. Thiel bi dugc Ihitc nghiem trong nhihig ngdy ndng Ihdng 4/2015. tgi TP. Ho Chi Minh.
Thiet bi cho ra sdn lugng cao nhdt khi do sdu l&p nu&c cdn chung cdl Id 0, OJ m (6 lit), nu&c nggt 0,02 m (17,5lit). Sdn lugng nu&c chung cdt dat 5,86 kg/m^ (tic 7-17h), img v&i biec xa trung binh 516 W/m'.
Tit khoa: Chung cdl nu&c sit dung ndng lugng mgi tr&i
ABSTRACT
Solar energy is clean source and endless reserves. Thus, putting Ihe device in order to exploit this source of energy is of great significance, especially for countries with good sunshine and radiation like Vietnam. In our country, the conventional solar stills are simple and low output To enhance the yield of distilled water, the team has built up equipment distilled water using solar energy with an area of 0,6 m- (evaporating area) couple wilh 8 evacuated glass tubes. Equipment is tested in the sunny days in april in Ho Chi Minh city. Equipment has Ihe highest output when Ihe brackish water depth is 0,01 m (6 liters) and the fresh water is 0,02 m (17,5 liters), production of distilled water can reach 5,86 hters/m' (from 7am to 5 pm) lo Ihe average radiation 516 W/m'.
Keywords: Solar still; Evacuated glass tubes.
ISSN 0866 • 7056
TAP CHl CO KHl VIET NAM, So 6 nam 2015 www.cokhivietnam.vn
NGHIEN C U T U - T R A O D O I
1. DAT VAN DE 2.2. Cong thioc tinh toan ly thuydt chung cat BU&C N u a c la nguon nang lupng thiet yeu va
thuc su can thiet cho su tdn tai ciia mdi ca th^
song tren trai dat. Nguon nuac sach dang hi de dpa bai su phat trien ciia cong nghiep gay ra su 6 nhiem cua ngu6n nuac. Khan hi6m ngudn nuac sach de uong dang thuc su la v i n de c4p thiet hien nay, nhat la nhung nguai dan dang sinh song tai cac viing sau, vung xa, bien gidi va hai dao, nhiing vimg mien thiiu nuac sach hoac nguon nuac bi 6 nhilm. Viec tao ra thiit bi chung cat nudc de bi8n nude phen, nuac lg, nudc man,...thanh nuac ngpt cho nguoi dan thuc su CO y nghia, nhat la nhihig qudc gia co lanh thd keo dai tren bien nhu Viet Nam.
Dunkle (1961) da dua ra mpt so cong thiic tinh toan ly thuyet ve chung cat nudc, nhu sau:
- He so truyen nhiet bang doi lim tir be mat nuac tdi be mat trong ciia kinh phii dugc tinh theo cong thlic sau:
Trong do:
o Ap suat hoi rieng phan tai be mat trong kinh phli:
Npi dung chinh trong bai bao, la trinh bay mgt so cong thuc tinh toan thiit bi chung cat nuac cua cac tac gia di trudc d i phuc vu tinh toan ly thuyet, nghien cuu c h i tao thiit hi chung cat nuoc sii dung NLMT dang Single Basin kit hop dng thiiy tinh chSn khdng (OTTCK) va thuc hien do dac thyc nghipm ciing nhu dua ra danh gia ve tiem nang img dyng thiet hi nay vao thuc te Clia TP. Ho Chi Minh ndi rieng va Viet Nam noi chung.
2. LY T H U Y E T T I N H TOAN
^ „ = e x p 25,317- (Nlm'-) (2)
o Ap suat hoi rieng phan tai mat nuoc:
= exp 25.317- (N/m') (3)
o T^^: Nhiet dp be mat nudc can chung cat ("C);
o T ^: Nhiet dp be mat trong cua kinh phu (°C).
2.1. Sor do nguySn ly ho^t dpng cua thiet bi - He so truyen nhiet bang hoc hoi tir be m§t nudc tdi be mat trong cua kinh phii dupc tinh theo cdng thlic sau:
Hinh I: Sa do nguyen ly thiet bi
h^.=0.0l6273xh^x^ ^ (W/m^K) (4)
- He so truyen nhiet bang biic xa tir mat nudc tod be mat trong ciia kinh phii dugc tinh theo cong thlic sau:
r(r„, +273)*-(7+273)*] , ,.,
ISSN 0866 - 7056
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NGHIEN cufu-TRAO Ddl
Trong do: A^: Dien tich Aperture ciia ong TTCK (A^ = N X 0,0548x1.72); ' '
= 0.9: Anh hudng cua he so N^: So dng TTCK;
A^: Dien tich be mat hap thu trong bdn chung ck hire xa. (basin liner) (m^).
1 + ^ - 1
,f? = O r ' ' ' ; ^ =<'•''«; He so buc xa cua be mjt 3_ ^ ^ j ^ . ^ , ^ G m j . ^ , kmh phu va mat nuac.
o- = 5.6697xlO^^W/m^^'': Hang s6 Stefan 3.1. K i t can cua t h i i t hi Boltzmann.
Thiet hi la su ket hgp cua cac thanh phln Tong he so truyen nhiet bang doi luu, sau:
hoc hoi va buc xa hi be mat nudc tdi b i mat
trong Clia kinh phii la: - 8 OTTCK cua hang Megasun loai dai h,^ = h^+h +h (W/m^AT) (6) 1.8 m^ dudng kinh ngoai d„ = 58 mm, dudng
kinh trong d^ = 47mm.
Theo ShivKumarva cong su (2013). , , ; t J . ,. , • • - Bon chung cat duac lam bang mox 304 - San luang nuoc chung ck dugc tinh day 1 mm, he so d i n nhiet >1^ = 16,2fF / mK, co theo cong thuc: dien tich boc hai A^, - A^ = 0,6m'. Kinh phii d^y 1^ = 0,004 m, CO he s6 d i n nhiet l^, = 0.7SW I mK . Bon chirag cat duac boc each nhiet day 0,05 ra KA(T„.~T,) ( k 2 \ • . J
" „ , ' = ; ^ x 3 6 0 0 - f - b o i v a t h e u c o h e s o d l n n h i e t l =0.0351»'/mA:.
L Wh, 0)
.A^'e.ffr^ "^"'^^jeOO f — 1 - Tim truyto nhiet (Basin liner) lam blng L yh) inox304dayl^ = 0,4mm,c6dientichAj = 0,6m'
duac son den Ah h4p thu NLMT.
o Nhiet an hoa hcri ciia nuac:
i = 2 . 5 0 6 x 1 0 ' - 2 . 3 6 9 x l 0 ' r , ^ + 0 . 2 6 7 8 x l 0 ' r , ' . - 8 . 1 0 3 x l 0 " ' 7 ' ^ - 2 . 0 7 9 x l 0 - ' 7 - ^ (J/kgK) (8) - Hi?u suat tuc thai ciia thilt bi dugc tinh theo cong thuc:
AA„,(r - T )
3.2. Thil tuc thwc nghiem
I^: Cuang do buc xa mat trcri trung binh trong 1
A r , - •• 1. K- X. u ' ,u . , i H'rib 2: Thuc nghiem song song 2 thiet bi chung cit A,: D,cn tich be mSt hap thu eua 1 ong TTCK nu&c su dung NLMT dgng Single Basin kk hop 8
(m'); OTTCK
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NGHIEN cufu - TRAO OPi
Thiet bi dugc dat tai TR H6 CM Minh co tga do ICS1 "49" BSc, lOe-Se'Sg" Dong, a dp cao 10 m so vai m$t dat, thiet bi dugc dat theo huong Dong-Bdc va Tay-Nam, lech 30 dp so vai huong chinh Dong-Nam.
(a) (b) (c) Hinh 3: Thiit bi do nhiit do (a); Biec xg mdi tr&i (b) vd toe do gio (c)
Thiet bi do cd chi so danh gia nhu bang 1, Biic xa mat trdi, nhiet dp tai cac diim mit va tdc dp gid deu dugc do true tiep bang may tai nhiing thdi diem nhat dinh.
Bdng I: Thong so thief bi do STT
1 2 3 4
Ten thiet bi May do nhiet do 12 kSnh PCE - T 1200 Dau do nhiet dp loai K
May do biic xa mat trcri PCE - SPM 1 May do toe dp gip Smart Sensor - AR826
Dai hoat dong -100 + 1300°C -50+1000°C 0H-2000(f/m' 0 + 15m/s
Do chinh xdc Sai s6 0.1%
±0.4% +0.5° C + 1 0 r / m ' + 5 %
±0.1m/s Nudc d nhiet dp mdi trucmg cung cap vao bdn chung cat luc 6h30 sang, Quy trinh nap nudc vao thiet hi nhu sau, nudc ngpt dugc tiep day cac OTTCK, sau do la mang chung cat, ti§p theo se dat cac gia dd de dat tim truyen nhiet rdi cho nudc can chung cat (d day ciing la nudc nggt) vao tam truyin nhiet. Do tim truyin nhiet dugc thiet ke kieu mang nen nudc can chung cat d nhimg trudng hgp la nudc lg, nudc phen,.. .se khdng chay xuong khdi nudc ngpt lam d nhiem khoi nudc ngpt ben dudi. 6 day, tdc gia diing hoan toan ngudn nudc thanh pho de thuc hien. Trong bai bao nay, tac gia thuc hien thi nghiem tren 2 md hinh cd ket cau hoan toan gidng nhau chi khac ve muc nudc trong thiit bi, cu the nhu bang 2.
Sau mpt thdi gian chung cat, nudc se hi thieu hut, Vi vay, cii sau 1 gid lay ket qua, tac gia se cip nudc bd sung bang tay mpt lugng nudc dung bang lugng nudc cat lay ra tir thiet bi. Trudc khi thi nghiem, bi m^t kinh phii va OTTCK dugc lam sach de bui ban khdng lam anh hudng tdi ket qua
thuc nghiem. ^
ISSN 0866 7056
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NGHIEN ClAl-TRAOPPl
Bang 2; Cdc phuang dn thi nghiem
H
Phuong an (PA) 1 2
Lvtfng nuofc ng9t 17.5 kg (cao 2 cm) 17.5 kg (cao 2 cm)
Lirong nu^c can chung clt 6 kg (cao 1 cm) 12 kg (cao 2 cm) 4. KET QUA
Dua vac kit qua do dac vh cuang dp biic xa mat trcri (I,), t6c dp gio (v), nhiet dp moi tracmg (Ta) cung nhu la nhiet dp tai bS mat nuoc ( T J , nhiet dp bS mat trong eua kinh phu (T^,) va san luong nuoc chung ck theo thoi gian 6 bang 3, qua do thuc hien viee tinh toan ly thuyet dua vao cac cong thlic tir (1) dSn (9), ta dugc ket qua nhu bang 4 cho PAI va bang 5 cho PA2.
Bang 3 • Thdng so do dgc Ihuc nghiem ngdy 15/4/2015 ciia 2 phuang an
STT
1 2 3 4 5 6 7 8 9 10 11
ThM gian (h) 7h 8h 9h lOh l l h 12h 13h 14h 15h 16h 17h
Is (W/m')
144 375 580 767 854 852 766 618 473 168 80
Ta CC) 27.4 31 33.2 34.8 35.6 37.6 36.7 35.5 34.5 33.7 33
v(m/s) 1.53
1.2 1.4 1.34 1.56 2.3 1.7 2.5 3.2 2.5 2.7
Tsw CC) PAI 30.7 36 46.5 57.2 69.5 76.8 80.7
• 83 80.5 74.9 71
Tgi CC) PAI 29.5 32.6 41 51.5
62 70.2 73.5 75.5 72 65 60.5
Tsw CC) PA2 30.5 35.6 44.6 54.9 64.1 73.5 78 82 79.6 77.5 71.4
Tgi CC) PA2 29.5 32.5 40.3 50.1 57.7 68 71.5 75.2 71.5 69 61
San luvng ( k g * ) PAI
0 0.02 0.05 0.115 0.295 0.345 0.5 0.58 0.6 0.53 0.48
PA2 0 0.015
0.04 0.085 0.19 0.25 0.375
0.49 0.53 0.51 0.47 Bdng 4; Ket qud tinh todn cho phuang dn 1
ThM gian (h) 7h 8h 9h lOh llh
(N/m')
4073 4839 7592 12899 21200
P „ (N/m')
4356 5824 10065 16959 29674
h „ (W/m')
1.02 1.46 1.81 1.97 2.38
h „ (W/m')
3.90 6.91 13.22 22.80 43.84
(W/m') 5.68 5.92 6.49 7.16 7.93
h|_
(WArf)
10.61 14.30 21.52 31.93 54.15
L. 10^
(J/kgK)
2.433 2.421 2.395 2.37 2.339
m (kgjh)
0 0.021 0.066 0.118 0.304
(kgtan')
0 0.035 0.109 0.197 0.506
ll,
(%)
1.44 4.02 6.76 8.56 18
ISSN 0866 - 7056
TAP CHi CO KHi VIET NAM, S6 6 nam 2015 www.cokhivietnam.vn
NGHIEN CUU - TRAO OCl
12h 13h 14h 15h 16h 17h
30597 35292 38430 33085 24296 19786
40597 47744 52447 47352 37464 31682
2.47 2.65 2.76 2.78 2.74 2.68
61.00 74.74 84.05 76.06 59.25 49.35
8.49 8.76 8.92 8.70 8.23 7.94
71.96 86.16 95.73 87.54 70.22 59.97
2.321 2.311 2.305 2.311 2.326 2.336
0.375 0.503 0.591 0.604 0.544 0.479
0.624 0.838 0.984 1.006 0.907 0.798
20.95 29.52 40.43 52.6 81.22
200
Bdng 5: Ket qua tinh todn cho phuang dn 2
T h M gian (h) 7h 8h 9h lOh llh 12h 13h I4h 15h 16h 17h
P^
(N/m')
4073 4813 7319 12043 17363 27777 32377 37944 32377 29029 20248
(N/m') 4307 5700 9141 15204 23328 35292 42690 50355 45630 41807 32237
(W/m') 0.96 1.42 1.65 1.83 2.16 2.25 2.50 2.65 2.72 2.69 2.68
h ^ (W/m')
3.65 6.61 11.39 19.62 32.76 50.19 64.44 78.73 72.31 65.84 50.27
(W/m') 5.16 5.37 5.82 6.40 6.91 7.54 7.80 8.06 7.86 7.70 7.24
(W/m') 9.77 13.40 18.86 27.85 41.83 59.98 74.74 89.44 82.89 76.23 60.19
L. 10' (J/kgK) 2.433 2.422 2.400 2.375 2.353 2.330 2.318 2.308 2.314 2,319 2.334
m (kg/h)
0 0.018 0.044 0.085 0.192 0.256 0.390 0.500 0.546 0.521 0.484
(l^torf)
0 0.03 0.073 0.143 0.321 0.426 0.65 0.835 0.911 0.868 0.806
1„
(%)
1.13 3.5 4.55 6.2 11.48 14.36 22.97 34.33 47.65 77.49 203.5
Sau khi thuc nghiem 2 phuang an tren 2 thiSt chung cit nudc sir dung NLMT, dang Single Basin k a hgp 8 OTTCK, xet d cung cudng dp buc xa mat trdi, van tdc gid va nhiet dp moi trucmg, ta thay:
Vdl cung lugng nudc ngpt 17.5kg, nhung lugng nudc can chung cat cang mong, d diy la 6 kg (PA 1) so vdi 12 kg thi san lugng nudc chung cit cang ldn, dugc bieu dien theo hinh 9.
Didu nay chung td ring, dung Iugng nudc can chimg cat cang nhd, mdng cang lam giam quan tinh nhiet, nudc ndng len nhanh han va tdc dp bay hcri nhanh han, tir dd san lugng nudc chimg cat tang cao han. San lugng nudc chung cat cho PAI la 3,515 kg/0,6m^ (tir 7-17h), tang 15,93%
SO vdi PA2 la 2,955 kg/0,6m2 (hi 7-17h). 6
day, neu xet trSn 1 m^ dien tich bdc hoi thi san lugng nudc chung cat cho PAI la 5,86 kg/m^ (tir 7-i7h), tang 15,93% so vdi PAZ la 4,925 kg/m^
(tir7-17h).
- Biic xa mat trdi ldn nhat tii 10-13h, trung binh khoang 809 W/m^ nhung nhiet dp mat nudc ldn nhat lai vao khoang tir 12-15h, hinh 4. Day la dp tre ciia su gia tang nhiet dp nudc theo thdi gian, vi cudng dp biic x? tang dot ngpt khong thS lam nhiet dp nudc tang manh ngay vao thdi diem nay, ma phai mat mpt khoang thdi gian nhat dinh khdi nudc mdi dugc lam ndng. Phan cdn lai, biic xa mat trdi giam manh tir 13-17h nhung nhiet dp nudc giam nhe trong khoang thdi gian nay, dd cdng la do dp tri Clia su suy giam nhiet dp nudc theo thdi gian. ^
ISSN 0866 - 7056
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NGHIEN cufu-TRAODOI
- San lugng nudc chung cat dugc quyet dinh bdi nhiet dp be mat nudc va dp chenh Ipch nhi^t dp giiia be mat nudc (T ^) va b^ mat trong cua kinh phii (T^^). Do vay, nhiet dp hi mSt nudc cjing ldn va dp chenh lech nhiet dp ciia nudc va kinh phu cang nhieu thi san lugng nudc chung cit dugc cang ldn. Nhm hmh 4 va 5 ta thiy, tir ll-17h nhiet do nudc cao nhung tu 13-17h dp chenh lech nhiSt dp giua be mat nudc va kinh phu ldn nen lugng nudc sinh ra trong khoang thdi gian 13-17h ldn. D§
chenh lech nhiet dp xuat phat tir dieu kien giai nhiet den tir nhiet dp moi trudng va tdc dp gid. Tu 13-17h tdc dp gid ldn va nhiet dp mdi trudfng dang cd xu hudng giam trong khi nhiet dp mat nudc ldn nen cho ra san lupng nudc chung cat ldn.
••
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NhMl 4$ bt mil OUAE vi mfl tnmg Clia kinh phd Ikng v
^ ^ - S ^
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9Mn OAOQ 09Q0 lotn 1100 I20O 1300 1 n»ifwi(h)
— i . i . n c i W A i ) - ^ T .«(oCj(pAi) - ^ I J U O C M P A ; i>i nrng phuong dn
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400 l*O0 ItcDO ITOO
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Hinh 4. Do thi hieu diin nhiet do be mat nuac va mgt trong ciia kinh phii img v&i timg phuang a (ngdy 15/4/2015)
Sin luprg tlnrc n g h i ^ nuiic chimg cat ijng vdi limg phuong
07<» 0«00 0»00 1I>00 MOO 12:00 1)00 14:00 IJOO IHOO 17:00 AuTlllc
—Stoliil?mihipcinh.^0(^){PA2) - . - S M . \mp^ thyc i^hifn Owl,) (PAD
Hinh 5: Do thi biiu diin san lugng thuc nghiem nu&c chung cdt img v&i limg phucmg dn (ngdy 15/4/2015)
ISSN 0866-7056
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NGHIEN CUU - TRAO OPl
So laob an lugnf; nm: chut^ CM giin ihvt n ^ ^ vi iinh taia cho 2 phsmg kt
Hinh 6: Do thi so sdnh sdn luang nu&c chung cdt giiea thyec nghi&m vd ly thuyet tinh todn ung v&i 2 phuang dn (ngdy 15/4/2015)
S. KET LUAN
Hmh 6, so sanh san lugng nudc chung cat giiia do dgc thuc nghiem va tinh toan ly thuyet d 2 phuang an cho thay chenh lech khdng Idn, tu day cd the ket luan nhiing cdng thiic ly thuyet tinh toan tir (1) den (9) do cac tac gia di trudc la hoan toan cd thS tin cay de lam tien dS cho cac tinh toan va thiet ke thiet bi chung cat nudc sii dung NLMT. Nhin vao bang 4 va bang 5, cd the ndi he sd trao ddi nhiet bang boc hoi hew (chiu anh hudng bdi Tsw va Tgi) la thdng sd quan trpng nhat, quyet dinh den hieu suat cimg nhu san lugng nudc chung cat, cho chiing ta cai nhin true quan ve hieu qua cua thiet bi.
Tir san lugng nudc chung cat dugc cpng vdi thiet k6 dan gian, de ch6 tao, nhdm tac gia manh dan de xuat iing dyng thiet bi chung cat nudc sir dung NLMT dang Single Basin ket hgp dng TTCK vao thuc te, gdp phan giai quyet tinh trang khan hiem nudc cho ngudi dan d nhimg vimg mien thieu nudc sach, hoac ngudn nudc bi 6 nhiem. •
Ngay nhan bai: 14/4/2015 Ngay phan bien: 18/6/2015 Tai lifu tham khao:
[ 1 ]. Hoang Dinh Tin, Hoang Thi Nam Huong; lfng dung ndng luang mat tr&i de dun nu&c nong vd sdn xudt nu&c nggt fie nu&c biin, NXB. Dai hpc Qudc gia TP. Ho Chi Minh, 2012.
12]. TS. Nguyin Thg Bao, Solstill - A simulation program for solar distillation systems, TP. H6 Chi Minh, 1998.
[3]. Ragh Vendra Singh, Shiv Kumar, M. H. Hasan, M. Emran Khan, G. N. Tiwari, Performance of a solar still integrated with evacuated tube collecrtor in natural mode, India, 2013.
ISSN 0866 - 7056
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