r/ r/
GIAI PHAPTHIETKETIET KIEM OIEN NANG CHOHETHONG f)IEU HOA KHONG KHI CONG SUAT LCIN
Pham Van Lucmg Nguyen Anh My
ABSTRACT
In the Builings, for example: T1 Noi Bai Airport, Vincom city Tower, Ha Npi- Daewoo Hotel,... Heat, ventilation and air-conditioning (HVAC) is highest con- sumtion electric so the solution of HVAC design is the first intereted of managers,
designers, technichers.
Th.S Pham Van Luorng Th.S Nguyen Anh My Vien Khoa hoc va ky thuat moi t r U ^ g
TrUdng Dai hoc Xay diTng 55 dudng Giai Phong, Hai Ba TrUng, Ha Noi Di dong: 0912151 466 Email: [email protected]
1. Khai quat ve cac he thong dieu hoa khong khi cong suat Idn
7.7. N\qt so he thong dieu hod khdng khi Idn tren The gidi
He thdng OHKK eho dUdng ham xuyen eo bien Mangsa(English Chan- nel Tunnel). Oudng ham dai 50km, ngam dUdi nUdc, ndi lien 2 nude Anh va Phap. oay la he thdng OHKK eho ham ngam Idn nhat The gidi. Oudng ham dupe lam lanh bdi 2 he thdng Chiller vdi 8 multi-stage centrifugal Chillers, eung cap 22.750 TR (79.900 kW) lanh. He thdng dupc lap dat nam 1994 sddung gas R-22.
He thdng OHKK cho toa thap ddi Petronas (Petronas Towers - Kuala Lumpur, Malaysia). Cdng trinh toa thap ddi Petronas la mdt trong nhdng toa nha cao nhat The gidi vdi 88 tang. He thdng OHKK gdm 6 may lam lanh nude kieu Ii tam (Turbo- Master centrifugal Chillers), vdi tdng cdng suat lanh la 30.000TR.Trong dd ed 3 electric-driven units va 3 steam turbine-powered Chillers. Ca 6 Chill- ers sd dung gas R-134a, loai tac nhan lanh thay the tac nhan lanh pha huy tang dzdn.
7.2. A^of sd He thong dieu hod khong khi Idn d Viet Nam
d Viet Nam, he thdng OHKK edng suat Idn (3.000-6.000 TR) cdn it, cd the ke mot sd he thdng nhU: he thdng OHKK cua Trung tam hdi nghi Qude gia (edng suat 4.176 TR) gdm 8 Chiller edng suat 172 TR/may, 8 Chill- er hop khdi edng suat 345 TR/may va 2 bom nhiet edng suat 846 kW/may do Ode thiet ke; he thdng OHKK cua
khach san Daewoo (cdng suat 3.700 TR) gdm 2 Chiller va gan 200 may cue bd do Han Qude thiet ke, tieu thu dien 800.000-1.300.000 kWh/thang;
he thdng OHKK cua toa thap ddi Vin- com City Tower (edng suat 2.720 TR) gdm 4 Chiller edng suat 680 TR/may do Viet Nam thiet ke (TS.Le Nguyen Minh chu tri); he thdng OHKK cua nha ga Tl San bay Ndi Bai (edng suat 2.190 TR) do Viet Nam thiet ke (TS.Le Nguyen Minh chu tri cdng nghe); he thdng OHKK cua nha may det Ha Ndi (cdng suat 2.190 TR),...
Phan Idn thiet ke he thdng OHKK trung tam cdng suat Idn CfViet Nam deu do cac cdng ty tu van thiet ke nudc ngoai dam nhiem, tuy nhien nhieu thiet ke ehua dupe hpp ly va xa la vdi dieu kien khi hau Viet Nam va sau mot thdi gian hoat dpng da phai nang cap vdi muc dich tiet kiem nang lupng. Bdi vay, viec nghien cdu nang cao chat lupng thiet ke nham dap Ung dupc su phat trien cua nganh OHKK va phu hop vdi dieu kien khi hau Viet Nam la edng viee rat can thiet.
7.3. Phuang phap xac dinh tieu thu dien ndng khi thiet ke he thdng dieu hod khdng khi
Theo ARI Standard 550/590, thi mdc dp hieu qua cua may lanh khdng ehi the hien qua gia tri tieu thu dien kW/Ton d 100% edng suat ma duoc the hien qua gia tri chay non tai tich hap (IPLV): IPLV = M(a/fK+h/B+d C-^d/D), kW/Ton
cae he sd a, b, e, va d la thdi lUpng van hanh d eac mUe 100%, 75%, 50%,
i^VilTlfif . 8.2009 85
va 25% edng suat lanh trong eac edng trinh t h d n g dung theo sd lieu khi hau trung binh eua My (a=0.01, b=0.42,c=0.45,d=0.12).
Dua tren ket qua x d ly sd lieu khi hau xay d u n g eua GS.TS Tran Ngpc Chan (Bang phan bd t-l ddng thdi), TS. Le Nguyen Minh de xuat cac t h d n g sd de tinh gia tri IPLV eho dieu kien khi hau Ha Ndi nhusau:a=0.021, b=0.411,c=0.568,d=0.
1.4. Kit ludn
Ky thuat OHKK tren The gidi da dat den trinh dp cao, viec nghien cdu nang cao chat lUpng thiet ke cho cac edng trinh xay dung d Viet Nam la cdng viec rat can thiet.
Can quan tam den cdng tac x d ly 50 lieu trUde khi dUa vao tinh toan.
Tinh toan theo TCVN thi sd lieu khi hau t h u d n g nam d tri sd cUe dai, dieu nay rat it khi xay ra. Dung sd lieu khi hau da dupc x d ly eua GS.TS. Tran Ngpc Chan va de xuat cac t h d n g sd d e t i n h gia tri IPLV cua TS. Le Nguyen Minh la phu hpp hon trong tinh toan he t h d n g OHKK.
2. Oanh gia hieu qua tiet kiem dien nang cho he thong DHKK trung t a m cong suat Idn
2.7. Tieu thu dien ndng trong he thdng dieu hod khdng khi cdng sudt Idn
Tinh toan lupng dien tieu t h u : -I- Vdi may khdng sd dung bien tan: Oien tieu thu (kWh) = kW/
TR*TR*Sd g i d chay may.
-I- Vdi may s d d u n g bien tan: Oien tieu thu (kWh) = IPLV*TR*Sd gid chay may.
2.2. Oanh gid hieu qua may lanh khi van hdnh non tdi
Gia tri IPLV eua may lanh dupc cae nha san xuat dua ra n h u bang 2.1:
2.3. Dieu khien tiet kiem dien ndng bdng sir dung bien tdn
Thiet bi bien tan la thiet bi dieu chinh bien ddi tde dp quay cua ddng CO bang each thay ddi tan sd ciia d d n g dien eung cap cho d d n g co.
Nhdng Uu diem khi dieu khien bang bien tan:
- Han che dupc d d n g dien khdi d d n g cao, d d n g tang deu t d 0 den 86i^&n'^TT^T . 8.2009
Trong d o : A = kW/Ton d 100% tai B = k W / T o n d 7 5 % t a i
A B C
C= kW/Ton d 5 0 % tai D= kWATon d 2 5 % tai
D 600
-c 500
§ 400 :o 300 H i ^ 200
100
0
;kiiillJ
36,4 I 28 19,7 11,4
euht
,n,n.m,m, J3,1 -5,3 -14
Nhiet d p ngoai, °C Hinh 1. So lieu khi hau va miJc dp chay may lanh trung binh o My, [7].
Bang 2.1. Hieu suat cac loai may t h e o IPLV Loai may
lanh Xoan de Pit t d n g True vit Li t a m
Kieu giai nhiet (Gn)
Gid Gid Nudc
Gid Nudc Nudc
Chi tieu danh gia COR (kW/kW)
3.99 3.6 4.8 4.29 5.1 9.4
IPLV (kW/TR) 0.88 0.99 0.73 0.82 0.69 0.375
Hinh 2. Qua trinh khi} am tren do thi I - d.
d d n g dinh mUc - 1^^ (khdi d d n g true tiep d d n g Idn gap 5-7 1^^, khdi d p n g sao-tam giac ed budc nhay luc chuyen ddi, khdi d d n g m e m Idn hon I d m 2 - 3 l a n ) .
- Tiet kiem nang lupng do cdng suat tieu t h u dien trong b o m - quat phu thuoc vao tde dp quay theo ham bae 3: N=f(n^), cdn luu lupng ti le tuyen tinh. Khi dieu khien bang van:
'^van=NXa„/n„3„- Khi dieu khien bang bien tan: N.^^-N^xf^^yp.so- ^ ^ n g suat
^(^ N - Trang thai khong khi ngoai nha.
T -Trang thai khong khi trong nha.
V - Trang thai khong khi cap vao nha.
HO - Qua trinh khCf am trong dan lanh AHU.
QV - Qua trinh say khong khi trang dan nong AHU.
tiet kiem duoc: N= N - N ,„.
van VSD
2.4. Ket ludn
each danh gia sU lam viec cua he t h d n g OHKK la theo hieu suat eua he t h d n g d khoang t h d i gian lam viec nhieu nhat (che d p chay non tai) chd khdng phai d t h d i diem day tai.
Odi vdi he t h d n g OHKK trung tam cdng suat Idn t h u d n g sd d u n g may lanh kieu truc vit hoac Ii tam, loai Chiller Ii t a m giai nhiet nude eho hieu qua tiet kiem dien nang nhat.
Bang 3.1. So sanh hieu qua tiet kiem dien nang khi lua chpn phuong an vdi 100% tai.
Phuang an Cooling only Chiller
Heat pump Chiller Heat recovery Chiller
Chiller-t-ld hai
Pit tdng Gn gid
9.929.600 12.719.400
12.502.560
Gn nude 8.972.600
10.829.690 10.500.310
True vit Gn gid
10.672.000 13.606.800
13.389.600
Gn nude 7.905.400
10.190.100 9286210
Li tam Gn nudc 6.333.600
7.076.010 7.827.648 Bang 3.2. So sanh hieu qua tiet kiem dien nang khi lua chpn phuong an vdi IPLV.
Phuang an Cooling only Chiller
Heat pump Chiller Heat recovery Chiller
Chiller+ld hci
Pit tdng Gn gid
8.027.200 10.234.680
10.229.520
Gn nudc 7.308.000
7.926.350 8.696.720
True vit Gn gid
6.681.600 8.519.040
8.621.760
Gn nudc 6.896.200
7.499.640 7.962.870
Li tam Gn nudc 4.216.600
4.749.960 5.388.360
3. Gicii phap thiet ke tiet kiem dien nang cho he thong DIHKK trung tam cong suat Idn
3.1. tVldt sd gidi phap tiet kiem dien ndng trong he thdng dieu hod khdng khi
Cd rat nhieu giai phap tiet kiem dien nang eho he thdng OHKK cdng suat Idn nhU: chpn loai Chiller, Bom, Thap giai nhiet va gia thanh lap dat.
3.7.7. Tiet kiem dien ndng cho Chiller Sd dung dien nang nhieu nhat trong he thdng OHKK la Chiller nen phai sd dung Chiller hieu qua cao.
TrUdc day. Chiller thudng dugc tieu chuan hoa vdi dp chenh nhiet dp AT=10F(5,6°C) cho ca dan bay hai, dan ngUng va thap giai nhiet, dieu nay dUpc hieu la de de dang tinh toan. Ngay nay, vdi sU hd trp cua may tinh, ngudi ta mong mudn tang dp chenh nhiet dp AT de lam giam lUu lupng va theo dd giam cd bom, cd dng, day dien, ed van va nhU the la tiet kiem ehi phi. Hon nda, khi tiet kiem dupc nang lUpng bom la eho Chiller tang them hieu suat.
So sanh he thdng OHKK sd dung 2 Chiller 250 Ton dieu khien bang bien tan (VSD, IPLV=0,407 kW/Ton)
vdi trudng hop dung khdi ddng mem (SSS, IPLV=0,541 kW/Ton) thi sau 1 nam van hanh tai dieu kien khi hau Ha Ndi cd the tiet kiem dugc:
500 Ton x (0,541-0,407) kW/Ton x 3.470 h/nam = 232.557 kWh/nam.
Tuang duong: 232.557 x 1.500 VND = 348.835.500 VND.
3.1.2. Tiet kiem dien ndng cho Bam-Quqt
Trong he thdng OHKK giai nhiet bang nUdc thi tdng edng suat bom va quat thap giai nhiet bang khoang 42% cdng suat dien eua may lanh, neu cae bam hoat ddng vdi cdng suat khdng ddi thi khi he thdng OHKK giam edng suat (cat giam FCU) se dan den tdn hao edng suat dien d eac ddng co bom. Su ra ddi cua thiet bi bien tan (VSD) da dem lai kha nang tiet kiem nang lUpng dang ke trong cae he thdng bom, quat.
Phan tich che dp van hanh eua bom Ii tam chung ta ed the nhan thay Uu diem tiet kiem nang lUpng khi sd dung bien tan (VSD) so vdi sd dung van de dieu chinh:
- Khi dieu chinh lUu lUpng bang van: bom se lam viec vdi tde dp khdng ddi n=1.470 RPM, gia thiet bom lam viec vdi lUu lUpng G=l 00 l/s va trd lUc
he thdng H^=100m, edng suat ddng CO P^=132kW. Khi luu lUOng giam xudng cdn 60 l/s, trd lUc eua he thdng chi eon H^= 70m nhung edt ap thuc te cua bom la H^= 105m, nhu vay tdn that cot ap qua van se bang AH=105- 70=35m, va bom tieu thu cdng suat khoang P^=100kW.
- Khi dieu chinh luu lupng bang bien tan: khi luu lUpng giam xudng 60 l/s thi ddng ca bom se giam tde do tU n =1.470 RPM xudng n„,= 1.200RPM, edt ap cua bom dung bang trd lUe he thdng Hg,=70m va cdng suat tieu thu eua bam khoang Pj,=65 kW.
Nhu vay neu dupe dieu khien bang bien tan thi bam cd the giam dupe khoang 1/3 tieu thu dien.
3.1.3. Tiet kiem dien ndng cho Thap gidi nhiet
Hieu qua trao ddi nhiet eua thap phu thupe cac yeu td sau:
- Op am cua khdng khi, khi dp am 100% thi ehi cdn trao ddi nhiet hien nen hieu suat kem.
- Tde dp khdng khi cang cao cang tdt, be mat trao ddi nhiet eang Idn cang tdt.
Neu chon thdng sd khi hau ngoai nha Idn thi thap giai nhiet se rat Idn, vi vay can chon thdng sd khi hau ngoai
CtUnilST . 8.2009 87
nha hpp ly. Vdi nhiet dp khdng khi ngoai la 34,9°C,ddam63,5%thi nhiet dp Udt la 28,8°C. Nude ra khdi thap ed nhiet dp Idn hon nhiet dp Udt 5°C la 33,8°C, nude vao thap cd nhiet dp la 33,8-i-5=38,8°C, nhiet dp ngUng tu la 38,8-i-At =43,8°C. Khi giam nhiet do
' m m - * * •
ngung tu ta phai tang cdng suat thap giai nhiet nhUng giam dupe dien nang tieu hao (giam nhiet dp ngUng tu 2°C, ta phai tang thap giai nhiet len 1.5 lan va giam dupe dien nang tieu hao 1.5 lan).
3.1.4. Dieu khien tU dong che do van hdnh tiet kiem dien ndng he thdng DHKK
He thdng dieu khien tU ddng trung tam lanh (CPA) se td hop cac thiet bj bom, thap giai nhiet eiing vdi may lanh de tao thanh mot khau quan ly, van hanh trung tam lanh mdt each cd td chUc, de tdi Uu hoa hieu qua sddung nang lupng.
He CPA se tdi thieu hoa viee tieu thu nang lUpng cua thiet bi va dieu chinh tu ddng may lanh - bom - thap giai nhiet theo chuong trinh khdi ddng - ddng may dUa tren thdng sd khdng khi ben ngoai, thdng sd khdng khi ben trong nha hay nhiet dp nUdc lanh. Bam cap nUde lanh. Bom nUdc ngung, Thap giai nhiet, va May lanh se dugc khdng che rieng biet ddi vdi thdi gian khdi ddng va ddng may tdi Uu. Chuang trinh se dinh xem nhiet dp nude ed du de ddng may nen trUde khi de thdi gian may khdng sd dung.
3.2. LUa chon gidi phdp thiet ke he thdng dieu hod khdng khi cdng sudt Idn
3.2.1. He thong DHKK chi co che do Idm mdt
He thdng OHKK nay sd dung may mdt chieu lanh - Cooling only Chiller, cd kha nang lam lanh va giam am, nd thich hpp eho eac nai ed khi hau chu yeu mot mua nong.
Bd phan chu yeu eua he thdng OHKK nay gdm: may lam lanh nudc Chiller (ed the la giai nhiet nude hoac khi, may lanh loai Ii tam hay true vit).
Bam nudc lanh. Bom nude giai nhiet, Thap giai nhiet, Dan trao ddi nhiet, Be nudc bu. Be nude bd sung. Bom nUdc bd sung, dUdng dng dan nude lanh.
thiet bi phu,...
3.2.2. He thong DHKK cd the Idm mdt hoac sudi dm
He thdng OHKK sd dung may Heat-pump Chiller ed the lam lanh, sUdi am, lam khd, nd thich hpp eho nhdng vung cd khi hau thay doi theo mua, he thdng cdn thich hpp eho nhdng cdng trinh ed nhu eau sd dung ddng thdi ca nhiet va lanh.
He thdng cdn tao mdc dp ddng deu eua nhiet dp va dp am khdng khi trong phdng do ed he thdng thdi gid va tuan hoan khdng khi tdt han han.
3.2.3. He thong DHKK cd the Idm mdt hoac khd dm
6 mien Bae cd mdt khoang thdi gian nhiet dp khdng khi nhd han 16°C, dp am tuong ddi cp >90 % va khi gid mua thay doi hudng thi thudng ed hien tUpng dpng suong. Oay la khoang thdi gian rat khd dieu tiet va thdi lupng khoang 370 gid trong nam.
Qua trinh sd dung may lanh thu hdi nhiet - Heat recovery Chiller de lam khd cd the bieu dien tren dd thi l-d nhu sau: qua trinh HQ thUe hien khi khdng khi di qua dan lanh, qua trinh QV thUe hien khi khdng khi di qua dan ndng cua AHU, nhu vay sau khi di qua AHU khdng khi ed thdng sd O (t=13°C, cp=80%) se dem den trang thai V (t^=27,5°C, cp=32%) vdi ehi phi nang lupng thap nhat.
3.2.4. He thdng dieu hod khdng khi sddung lanh bdng mdy lanh vd Id hai.
He thdng OHKK nay cd the sd dung ddi vdi nhdng vung cd khi hau mija Odng khdng lanh lam va thdi gian lanh khdng keo dai. Khi dd mua ndng se chay may lanh cdn mua lanh Id hoi se eung cap hoi nude ndng di vao cac dan trao ddi nhiet de sUdi am chocac phdng.
He thdng OHKK nay se sd dung may lanh mot chieu hieu suat cao, van hanh Id hoi cd phdc tap nhUng dem lai hieu suat cao hon sd dung thanh dien trd sUdi.
3.3. Tinh todn hieu qua tiet kiem ndng luqng khi lua chon phuang an thiet ke
Tinh toan eho he thdng OHKK cua Thap ddi Vincom ed cdng suat
lanh 2.798 TR, cdng suat sUdi 621 TR, cap OHKK 2, chat lam lanh la R22, Rl 34a, RI 23. Bang ket qua tinh toan hieu qua tiet kiem dien nang cho eac phuang an (kWh/nam).
3.4. Ket luan
Cd rat nhieu giai phap tiet kiem dien nang cho he thdng OHKK cdng suat Idn nhU: lUa chpn loai may lanh, lUa chpn sa dd cap nhiet lanh hpp ly, sd dung bien tan, dieu khien tu ddng,...Tuy tdng cdng trinh ma ngUdi thiet ke cd the chpn cho phU hpp.
Vdi he thdng OHKK edng suat Idn thi lua chpn Chiller Ii tam ludn la giai phap tiet kiem dien nang nhat.
4. ket luan va kien nghj 4.1. Ket ludn
- Hien nay chUa cd tai lieu hUdng dan thie't keOHKK cdng suat Idn, bdi vay viec nghien cdu de dUa ra chuan la rat can thiet.
- Thiet ke he thdng OHKK cdng suat Idn can quan tam yeu cau ve cdng nghe cap nhiet-lanh, tri sd IPLV cua may lanh nham dam bao tiet kiem nang lupng.
-Tinh toan tieu thu dien cd nhieu each, he thdng OHKK sd dung bien tan dem lai ehi sd tieu thu dien nang thap nhat.
- Vdi he thdng OHKK cdng suat Idn thi nen sddung may Ii tam vi kha nang tiet kiem dien nang hon han cac loai may khae.
4.2. Kien nghi
- oanh gia tieu thu dien nen sd dung phuang phap IPLV cua ARI va chu y den dieu kien khi hau Viet Nam.
- LUu y chpn giai phap cap nhiet- lanh trong thiet ke he thdng OHKK de tiet kiem dien nang nhieu nhat trong
van hanh, sddung. •
TAI LI|U THAM KHAO
l.Tieu chuan Viet Nam TCVN 5687:1992, Thong gio-Dieu tiet khong khi-Sadi am, Tieu chuan thie't ke', NXB Xay dung, Ha Noi, 2002.
2.Pham Van Luong, Thiet ke tiet kiem nang li/ong he thong dieu hoa khong khi trung tam cong suat Idn, Luan van thac sy ky thuat. Ha Noi, 2006.
3.ARI Standard 550/590.
8 8 i ^ U n T l ^ T . 8.2009
