CHO CAC ^ N E L NRfiQ LlT^NG MAT TRdi # Q I I A N f i l C A I
ki ^
f
19. NGUYEN TRQNG HA ty TNHH MTV loc hda ddu Binh San)
luy dgc gia phucfng itn It/a chgn goc
•)Cfc x^ mat trdi ctiieu den mat thu cua
\n tfcti di/a tren md hinh giai tich vS.qi^n
^.^^Y-'^^^i'mQt mjhfhing nghieng bat Icy vdi cac tga dg df^f, . _ . M0t trdrvi cirdng dg ton^x^ va tdn x^ do ditqic trSn mat bang't^imgi^
thdi diSr^rong nam. Gd^nghieng t9fitu popt vfng vdi giit tri ci/c d^i cua tong x^
tren mat phang nghieng tim dirge nha^am Solver trong MsExcel. Ket qua
nghien cutu cho ta cac gia tri tifOng Cfng cua popt cd'dinh, theo mua va theo tCfng thang trong nam de quy vi cd the li/a chgn khi lap dat va SLf dyng cac panel
nang li/gng mat trdi (NLMT) cua minh dugc hi^u qua nhat.
1. Dat vdfn d l
Nang lifdng mat trdi la mdt trong cac nguon nang lifdng sach vd vd tan, nd Id nguon gdc cua cdc ngudn nang Itfdng khdc tren trai dat. Loai ngifdi da bie't tan dung ngudn nang Itfdng qu;^ gid ndy tif ra't Idu, tuy nhien viec khai thdc vd suf dung ngudn nSng lifdng ndy mot cdeh hieu qud nha't thi van la van de ma chung ta can quan tam nghien cifu.
Ngay nay viec lap dat vd siJ dung cdc panel NLMT de phdt dien, ham nifdc da trd nen phd bie'n d mpi vilng miln ciiaTdqud'c.
Cdc ky thudt va cdng nghe mdi da vd dang dufde dp dung de che' tao ra cac panel c6 hidu suat cao hdn vd gid thdnh ngay cdng tha'p.
Ben canh do viec lap dat mdt panel sao cho hieu qua 1dm viec cua nd dat cao nha't la mdt vd'n di kinh te' - ky thuat can dufde giai ddp mdt each khoa hoc.
Mdt quy tac phd bie'n la khi lap dat cdc bd thu NLMT thi be mat thu phai hifdng \i phia chinh Nam hoae chinh Bac (gdc phifdng vi y
= 0 hoae y = 180°) tily theo vi dp dia ly hay gdc lech cua mat trdi so vdi mat phang xlch dao. Khdc vdi viec xdc dinh hifdng, viec xdc dinh gdc nghieng td'i ifu cho cac bd thu rat phifc tap vi khdng nhi?ng do Trai dat tif quay quanh true cua nd vd chuyen dpng quanh mat trdi theo quy dao e-lip nen vi tri tifdng ddi cua Mat trdi so vdi Trdi da't thay ddi tuin hoan theo thdi gian trong ngay va trong nam ma con phu thudc vdo cufdng dp cdc thdnh phan bite xa mat trdi, sud't phan chi^u eda mat da't, tpa dp dia 1^ tai mdi dia phifdng...
Do dd viec xdc dinh gdc nghidng td'i ifu cho cdc panel NLMT de nang cao hieu qua suf dung chiing khdng chi la vd'n d^ ly thuyet ddn thuan ma Id mdt yeu c l u ca'p thid't tif thifc tien.
6 <§> THONG TIN KHOA HOC VA CONG NGHE - So 06/2011
cf" 2. Thid't l$p md hinh giai tich d^ng htfdng eda Reindl du'de cdc tac gia Bai todn xdc dinh gdc nghidng td'i mi yX,pt trong [2] ddnh gid Id cd do chinh xdc cao khi cho cdc panel NLMT trong bai bdo ndy difdc mat thu quay v l hifdng Nam:
Hn — HaR «f"d (4)
«<!=?«» + (i-?)(^-T*)[i + JS'^«'flfl)l
»mhi (5)xay difng t^ cdc md hinh 15^ thuye't vd thifc nghiem du'de trinh bay trong [1], [2], [3] vd sd'lidu khi tifdng quan trie du'de trong [4].
Md hinh sif dung trong bdi bdo ndy thifdng
difdc bid't de'n vdi tdn gpi Id md hinh bd't ding xhdnh phin phdn xa tif mat dat tinh theo hufdng (thanh phan tdn xa khdng ddng nhd't ^ 5 hinh ding hifdng ciaa Liu-Jordan:
theo moi hifdng) cila Reindl (1990), nhtfng khdng phdi hoan todn do Reindl xdy dufng nen md Id ke' thifa tu' md hinh dang hifdng kinh didn cila Liu-Jordan (1962) nhtf trinh bdy dufdi ddy.
« / , = H « p ( ^ ^ (6)
X .
1 t 1 1
1 1
^^- .N
""'^
J .
/
^
riiMi •
','.*' .*•
V ' " • • • . • • •
*
KUc w^'te 10 inSi
jJlMlf 'U'« I^W^
•••••:'^r
1 ) . . . . • • • •
Cdc dai lifdng trong cdc cdng thiJc trdn Id:
Ho- Tdng xa trung binh cua mot ngay trong thdng do difdc tren mat bang, [W/mVngdy];
Hd- Tdn xa trung binh cua mot ngay trong thdng do difdc tren mat bang, [W/mVngayj;
Cdc gid tri Ho va Hd trong bdi bao ndy difdc tdc gia»J[d'y theo so'lieu thd'ng ke d tram
Hinh minh hoa quy Udc cdc goc trong mo hinh tinh todn
Tong xa H-p chie'u ddn mot mat phang nghieng ba^t ky Id tdng hdp cua ba thdnh phin: Tnfc xa HB, tdn xa HD va thanh phin phan xa tuf mat da't HR theo cdng thiJc:
HT = HB+HD+HK (1)
Thanh phan tnfc xa tinh theo md hinh ciia Liu-Jordan sau khi hidu chinh lai cdng thiJc cua Hottel-Woertz difa ra nam 1942 dd'i vdi panel d bdn clu Bac, hifdng v l xlch dao la:
Hg = (H^-Hg)R^ (2)
Ja JNan Thang
Ho
Hd
g'^' nn 1 3718
1970 Thang
Ho
Hd
7 6904 2478
LI irons 2 4738 2457
?Dang 3 5304 2513
airoi 4 6292 2747
aay:
5 6844 2606
6 6774 2668
i
8 6628 2857
9 5438 2568
10 4158 2176
11 3281
1989 12 2806
1771 Hb—Ho — Ha la trifc xa trung binh ngay ciia thdng, [W/mVngay]; (7)
(p- gdc vT dd, d TP Quang Ngai la'y bang +15° (VI do Bac);
6- gdc lech ciia Mat trdi, la gdc lech giifa difdng thang nd'i tam Trdi da't vdi tam Mat trdi so vdi mat phang xich dao khi Mat trdi di qua kinh tuye'n dia phifdng, ddn vi tinh la [do], difdc xdc dinh theo cdng thiJc Cooper (1969) la:
S = 23.4S.^f^^^] (8) R»
36S
(3)
Trong do n la ngay thu" n trong nam, quy Thdnh phin tdn xa tinh theo md hinh bat ^^^ n=l la ngay 1 thdng 1;
THONG TIN KHOA HOC VA CONG NGHE - So 06/2011 ^ 7
a>„.a>;. la gdc gid Mat trdi Ian lifng vdi mat b^ng va mat phing nghidng, ddn vi tinh Id
[radian], xdc dinh theo cdng thiJc:
, _ .(<«>« = Arccos(-tan4>tan5) | (9)
" - - " " ° l ArecosI-tanC^ - p)tan5ll
p- sua't phdn chie'u cua mdt d^t, Id'y bdng 0,2""
P- Id gdc nghidng ci3a panel so vdi mat b^ng vdi quy ufdc gdc ^ > 0 khi mat thu hifdng ve phia chinh Nam, /?< 0 khi mat thu htfdng ve phia chinh B^c. Tdc gia dufa vdo d^u tri tuyel dd'i trong phtfdng trinh (5) chi mang tinh thual todn dd gidm bdt sdltfdng phdp tinh.
Bdi todn cd the du'de phdt bidu nhif sau:
^Tiw cdc gid tri gdc nghieng cua mat thu /iZ'^-9(P,90"] de tS'ng ndng luang bite xa mal tr^ chie'u den mat thu
Itir = l[iH^ - "a)RkM + Hijfi^ + Hftk/»(^)1 dat gid tri Idn nha't trong nhitng khodng thdi gian cho trUdc trong nam.
Vi gid tri do difdc cua biJc xa mat trdi la trung binh ngay ciia tufng thdng trong n | m ndn gdc lech cua Mat trdi trong cdc cdng Siill&^cs tren se difdc thay bdi gid tri trung binh thdng theo cdng thiJc:
Tiling 7
8 9 10 11 12
Gdc nghifing yS>pt m)
19 6 12 30 41 45
Hifdng B^c BSc Nam Nam Nam Nam Tdng NL tren mat thu ca
nam (MJ/mlnSm)
Tdng NL trdn mat thu (MJ/mlthang)
806.80 743,22 597,23 514,65 428,23 395,60 7430.96 Bdng 2. Cdc gid tri gdc nghiing toi Uu cho bo thu phdng theo cdc miia trong ndm
S = ^ ^ (10)
m-la so' ngdy cua thdng thif k trong nSm, k = iTi2 5i tinh theo cdng thiJc (8) cho moi
ngay trong thdng.
3. Phdn tich kd't qua va nh|in xet
Bdng 1. Cdc gid tri gdc nghieng toi Uu cho bo thu phdng theo titng thdng trong ndm
Thang 1 2 3 4 5 6
Goc nghieng
yS>p. ( d p )
44.5 35
19 0 15 22
Hifdng Nam Nam Nam
#
Bac Bac
Tong NL tren mat thu (MJ/m-.thang)
532.70 552.27 617,60 679.54 786.52 776.59
Thang 11 12 1 2 3 4 5 6 7 8 9 10
G6c nghieng
^P. (do)
43.5
17
19
9.5
Hifdng Nam
Nam
Bac
Nam Tong NL tren mat thu ca
nam (MJ/m-.nam)
Tong NL tren mat thu (MJ/mlthang)
427.87 395.50 532.64 531.86 617.26 657.68 785,41 775.68 806.97 721.60 596.85 491.24 7340,37 Vide lifa chpn phifdng dn l^p dat thay doi gdc nghidng theo thdng, theo mil a hay cd' dinh tfty thuoc vao tinh thuan ldi vd muc dich ciia ngifdi siJ dung. Tuy nhidn can chu y rang vdi cdc bd thu NLMT de ham nifdc thifdng la loai tuan hoan tif nhidn (khdng dung bdm) difa vdo hidu tfng Si-phdng nhidt trong tnfdng trong life, ndn cdc bd thu kidu nay ydu eau mdt gdc nghidng td'i thieu de dam bao tuan hodn tif nhidn vd thifdng difdc difa ra trong sd tay hifdng dan sd dung cua cdc nha sdn xua't. Do dd vide lifa chon gdc nghidng td'i mi phdi thda man ydu eau nay. Con dd'i vdi cdc ta'm pin NLMT hay he thd'ng nifdc cF"
8 ^ THONG TIN KHOA HOC VA CONG NGHE - So 06/2011
ndng tuan hoan cifdng biJp (d^ng bdm) thi khdng cIn dd y tdi.
Tuy tdc gia da ed' gang lifa chon md hinh phu hdp nhifng dp tin cay ciia kd't qud thu difdc van phu thudc nhidu vdo dd tin cdy eda sd'lidu quan trae thd'ng kd du'de trong [4]. Sif sai khdc vd vi dp dia 1^ ndi quan tr^c biJc xa Mat trdi so vdi gdc vi dp tinh todn tronf md hinh ciing cd thd gdy ra sai sd'.
Bdng 3. Gid tri gdc nghiing td'i uu cho b0 thu phdng cd'dinh
Dd thi 2. Hieu qud ndng luang cua bo thu thay dSi theo cdc phuang dn lua chon gdc nghiing td'i uu
5100
92 00
Thing 1 2 3 4 5 6 7 8 9 10 11' 12
G6c nghieng A>p.(do)
8
Hifdng
Nam
Tong NL tren mat thu ca nam (MJ/m^.nam)
Tdng NL tren mat thu (MJ/mlthang)
453,42 508,41 609,41 674,09 734,44 693,85 734,59 724,99 596.28 488,06 380,76 339.86 6938,17
Co dinh tt\eo thang Co dinh th«omua Codmhttieonsm
Do thi I. Bie'n thien gid tri gdc nghieng td'i uu cua cdc phuang dn theo 12 thdng trong ndm '
8l£n (Men c b ete ncNine us mi W ) tlMO tMrl (Ian 12 IMn(
trang nim
- Gia trf am la be mit thu hi/G«ig ve phu B^
- Gia tri diAMig la be m^ thu hi/omg ve ptwa Nam
4IMI 43i) Mm 33.0 38.0 iXD 18.0 IJJO 8.D a.D -2a -/.o : -U.0
-via -list
1
: •
\
1 1
1
L \ / 1 X
w G 7 /Jf i
/ 1
n
1 1
ij) a k
-CdAnhtheoth^ig - C o 4nh theo mua - C o d n ^ theo nam
4.Kd'tluan .^
Kd't qud phan tich trong bdi bdo ndy.-OTrc) thd^y: Nd'u thay ddi gdc nghidng, cuar*p^el theo cdc gia tri td'i ifU tifng mua thi tdng nang * lufdng biJc xa chie'u de'n mat thu se gidm khodng 2%, con nd'u dat bp thu cd' dinh vdi gdc nghieng td'i ufu thi tdng nang lifdng bifc xa chid'u dep b l mat thu gidm khodng 7,4%
so v^^tnfdng hdp thay ddi gdc nghidng cua JI0sS&\ theo cac gid tri td'i ifu tfifng thdng trong nam (do thi 2). Nd'u lifa chpn gdc nghidng khdng phu hdp thi hidu qud cua cdc panel hay bd thu cd the gidm di ra't n h i e u ^
Tdi lieu tham khdo
[1] Soteris A. Kalogirou: Solar energy engi- neering processes and systems, Copyright © 2009, Elsevier Inc. ,
[2] Ali Mohammad Noorian, Isaac Moradi, Gholam Ali Kamali: Evaluation of 12 models to estimate hourly diffuse irradiation on inclined sur- faces, Renewable Energy 33 (2008).
[3] John ADuffie, William A.Beckman: Solar engineering of thermal processes, John Wiley &
Sons, Inc,1980.
[4] Quy chudn xay dung Viet Nam, QCXDVN 02: 2008/BXD.
[5] Hodng Ducmg Hung: Ndng luang Mat trdi -ly thuyi't vd vcng dung, NXB KHKT2007.
THONG TIN KHOA HOC VA CONG NGHE - So 06/2011 ^ 9
