NLN* 118-7/2014*21
liNG DUNG CAC TRINH TlTDIEU KHIEN TIET KIEM NANG LI/OTNG CHO HE THONG DIEU HOA KHONG KHI KHU TRAI CUA CONG TRINH
LANG CHU TICH HO CHI MINH
TS. PHAM HAI T R U N G * , ThS, N G U Y E N HLfU SINH, KS. TRAN MANH HAI, Bd Tu Lenh Lang 1. Dat van dd
Hidn nay vdn dd su dung hieu qua vd tilt kiem ndng lupng dang dupe dat ra nhu mdt vdn d l mdu chdt vua dam bao cho an ninh nang lupng vua khdng chd phdt thai khi gay hieu ung nha kinh dd ung phd vdi vdn dd bidn ddi khi hdu ddi vdi nude ta. Lang Chu tich Hd Chi Minh id mpt trong nhOng cdng trinh trong dilm Qudc gia cd y nghTa chinh trj va van hda to Idn ddi vdi Dan tdc Cdc trang thidt bj d day ddu la cdc trang thidt bj hidn dai va Id cdc thidt bi tieu thu didn Idn, dac bidt cdc hd thdng lanh vd dilu hda khdng khi (OHKK). Do dd vide nghien cuu dp dung cdc giai phdp tidt kidm ndng lup'ng a ddy cd rdt cd y nghTa khdng chT ed ve mat kinh te ma edn vd mdt chinh tn xa hdi. Khdng nhijng thd ddy cOng Id mot trong nhu'ng don vj ddu tien trong todn quan dp dung cdc bidn phap tilt ki^m ndng lup'ng.
Trong bdi bdo nay cae tac gia gidi thieu vi^e dp dyng cdc he cung cdp gio co luu lup'ng thay ddi VAV-box thay cho hd thdng cdp gid vdi luu luang khdng ddi CAV vd dilu khiln lup'ng cung cdp khi tupi, nhdm cai thien tieu thu nang lup'ng cua h_d thdng DHKK khu trdi va danh gid kha nang tilt kiem nang lup'ng cua giai phap ndy.
2. Gio'i thi^u he thdng va giai phap ap dyng H§ thong didu hda khdng khi Khu trai cua Cdng trinh Lang Chu tjch Hd Chi Minh dup'c dua vdo su dung tu ndm 2009, thilt ke theo nguyen ly luu lup'ng khdng khi thay doi vd ty Id hda trpn khi tudi, khi tudn hoan thay ddi. Thdng sd nhidt dm trong eac phdng dieu hda duo'c duy tri bang cdc hpp van gip didu chinh luu lupng (VAV box - Variable Air Volume Box) va bp sdy dien. Luu lupng khdng khi cdp va hut cho cac phdng thay ddi phy thugc vdo tai nhiet trong phdng, thdng qua cac cam bien nhiet dp vd biln tdn dd dieu chinh luu lupng gid phij hp'p. He thdng dilu hda dup'c dilu khiln bdng cac thidt bi didu khiln sd true tilp (DDC - Direct Digital Control) MP581 va phdn mdm quan ly tda nha TracerSummit cua Hang Trane. He thing dilu hda khdng khi Khu trai da vd dang bao dam thdng sd nhidt am cua cdc phong dilu hda theo yeu cdu va tilt ki^m ndng lup'ng didn tidu thy. Tuy nhidn trong qud trinh van hdnh
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va nghien cuu cho thdy, cd the dp dung cdc trinh ty dilu khiln tilt kiem ndng lup'ng cho he thong nay, do la: trinh tu didu khiln hdp van gid dilu chfnh luu lup'ng vdi sdy didn; trinh tu didu khidn ty Id hda trdn khdng khi ngodi trdi va khdng khi hdi;
dilu khidn dat lai gia tn nhi^t dp phdng ddt trudc theo nhidt dp ngoai trdi.
3. Didu khidn hpp van gio didu chinh lu'u lu'p'ng
Trinh ty dilu khiln hop van gid dilu chinh luu lupng khdng khi lam mat vdi sdy dipn cu dupc mdta p hinh 1.
„ / \ *. IpWing s i y '^' Urn lanh
Hinh 1. Trinh tw diiu khien cO Theo trinh ty dilu khiln d hinh 1, khi nhidt dp trong phdng (Tphong) Id'n hon gid tn nhiet dp ddt trudc (Taa,), luu lupng khdng khi Idm mat cap vao phdng thay ddi tu gia tn nho nhat (Vmm) <Jln gia trj Idn nhdt (Vmax) <3e duy tri Tph^ng theo yeu cau.
Ngudc lai khi Tphong, thdp hdn Tag,, luu lupng khdng khi lam mdt cdp vao phdng se thay ddi tu Vmax (J^n Vmm- Trong trudng hp'p luu lupng khdng khi lam mdt cdp vdo phdng 6 Vmm. Tphong van thdp hon Ton sly dup'c dua vao lam viec d l duy tri Tphong theo yeu cdu. Vmm cdp vao phdng dupe xdc dinh thee tieu chudn v? smh mdi trud'ng vd dam bao bd sly lam viec toi uu, khong lam hong cac thanh sdy. Tuy nhien khi khong cd ngudi Idm vi$c trong phdng, Vmm cdp vao phdng co t h i dup'c dat thdp hon ni>a. Dd tidt kiem nang lupng ta cd t h i su dyng trinh ty dilu khiln hop van didu chinh luu lugng vdi sdy didn [1,2] nhu d hinh 2.
22* NLN-118'7/2014
•^'
sdy
Dead band
"•"»' Lam lanh
Ap dyng trinh ty diku khiln say vd hop dieu chinh luu lup'ng khdng khi VAV d" hinh 2 se cho phep tilt kiem ndng lupng do Vmm cdp vao phdng nhd han Vmm d hinh 1. Khi bd say Idm vide, luu lup'ng khdng khi cdp vao phdng se dup'c dua len Vreheat "^l "Jam bao cdc thanh sdy khdng bj hdng.
Ngoai ra, ndu nhiet dp phdng duy tri vdi sai s6 cho phep Idn thi vide tilt kidm ndng lupng co thd dgt dupc bang cdch ndi rdng dai chet (Dead band), vung ma t?i do say khdng lam vide vd luu luang khdng khi cdp vao phdng Id Vmm. Chuang trinh phan mIm dilu khiln hgp van dilu chinh luu lupng khdng khi vdi sdy theo trinh ty dilu khiln dup'c md ta a hinh 3.
Hinh 2. Trinh ti/ diiu khien mdi
Hinh 3: Chuong trinh phin mim diiu khien hdp van 4. Didu khien thay d i i ty le hoa trgn khong khi ngoai trd'i vd'i khdng Ithi hdi cua may didu hda d§ duy tri nhiet dp cdp vao
Khinhidt dp khdng khi ngpai trdi ndm a viJng du lanh d l Idm mdt khdng khi cua mdy didu hda, t^i cdc dilm nhidt dp nay dieu chinh cac van gid thay doi ty Id hda trpn khdng khi ngoai trdi vdi khdng khi hoi de duy tri nhigt dp didm thdi cua mdy dilu hda se tilt kidm nang lupng do khdng dung say didn va dan Ignh [1,2], Trinh ty didu khien thay ddi ty Id hda trpn khdng khi ngodi trdi vd khdng khi hdi ciia mdy dilu hda dup'c md ta a hinh 4.
TBA: Temprature Exhaust Air - nhigt dp khdng khi hdi Ta^: Temprature Suply Air - nhi$t do khdng khi cdp dupc yeu cau.
Tew: Temprature Outside Air - nhiet do khdng khi ngoai trdi
Toflmr: Temprature Outside Air - nhiet dd khdng khi ngoai trdi
TMA : Temprature Wllx Air - nhigt dp khdng khi hda trdn
dieu chinh Iwu lugng khdng khi vdi siy theo trinh ti/ mdi
Hinh4 Trinh twdiiu khien thay dii t^l$ hda trdn khdng khi ngoii troi vi khdng khi hoi
Hinh 4 bilu dien tardng hp'p khdng khi hdi ti>
khu vyc dilu hod co nhigt dg Tew vd khdng khf dug'c cdp vao c6 nhi^t dO TSA- 4 c h i dg hoat dgng cd t h i dug'c phdn chia nhu sau:
NLN* 1 1 8 - 7 / 2 0 1 4 * 23 Tai cdc nhiet d g ngodi trdi
TOA < ToAmm vd TMA < TSA, van gid ngoai trdi d u p c d u a vd vj tri min va sdy dug'c yeu cdu Idm vigc dd nang nhiet do khdng khi cdp tdi TSA.
Khi khdng khi ngoai trdi trong vung ToAmm < TQA < TSA, nhigt dp khdng khi cdp dug-c duy tri bdng d i l u chinh cdc van gid, luu l u o n g khdng khi ngcdi trdi dat max khi TOA=TSA- Trong khoang ndy he thdng hoat ddng d c h i dd 1dm lanh t y d o ;
- Trong vCjng TSA < TQA < TgtA luu l u p n g khdng khi ngoai trdi v l n dup'c duy tri d' m u e max d l Idm cho khdng khi tuan hda cd nhigt dp thap nhdt khi d u a vdo mdy d i l u hda de lam lanh;
- Tgi nhidt dp khdng khi ngoai trdi TOA >Tey\, l u u lup'ng khdng khi ngodi trdi d u y c d u a v l gid tri m i n , ddn lanh d u p e yeu cau Idm vigc d l ha nhidt dp khdng khi cdp.
Hinh 4 bieu didn s y didu chinh luu lug'ng khdng khi ngoai trdi n h u la ham cua cdc nhiet do cdp va hdi.
C h u a n g trinh phdn m d m dieu k h i l n ty Ig hda trOn khdng khi ngoai trdi vd khdng khi hdi cua may d i l u hda dug'c m d ta d" hinh 5.
5. Didu khien ddt lai gia t r i nhiet d g dat cua p h o n g t h e o nhiet d o ngoai trd'i
Quy c^nh thdng sd nhidt do vd dd dm cua cac phdng khu Trai la: T = 25 °C + 1,5 °C va f = 70 %± 10 %.
Tuy nhien trong qud trinh v d n hdnh, ddi v d i cdc phdng kho khdng cdn thidt phai duy tri thdng sd n l i i g t d m n h u dd dug'c quy djnh vd cd thd thay ddi d l t i l t kiem nang l u p n g sdy vao mua ddng va lanh vdo mUa he. Gid trj nhiet dp dat cua phdng Tsetpomt dup'c t u d d n g dat lai theo nhiet do ngodi trdi n h u sau:
Tseipomt = 20 °C ± 1,5 "C khi TOA ^ 20 °C Tsetpomt = 26 °C ± 1,5 °C khi TQA > 20 °C V d i viec ddt lai gia trj didm ddt nhigt d d cua phdng se t i l t kigm nang luo-ng say dien vao mCia ddng vd ndng lup'ng lanh vao m u a he. C h u a n g trinh phdn m e m d i l u khidn ddt Igi gia trj nhiet dp ddt cua phdng d u p c m d ta a hinh 6.
e . K d t i u a n
A p d u n g cac trinh t y d i l u k h i l n tidt kigm nang lug'ng cho hg thdng d i l u hda Khu trai cua Cdng trinh Lang Chu tjch H i Chi Minh gdp phdn tidt
Hinh 5' Chuung trinh diiu khiin ty 1$ hoa trdn khdng khi ngoai trdi va khong khi hdi
Hinh 6: Chuang trinh diiu khiin d$t lai gii tn nhi^t dg dat cue phdng
kidm khoang 4 - 5 % dien nang tieu thy cua he thdng do giam t h d i gian Idm vigc cua cac bO sdy didn. Vide nghien cCru, dp dyng cdc trinh t u d i l u k h i l n t i l t kiem nang l u p n g cho hg thdng d i l u hda khu trdi da khdng dinh s u Idm chu cdc t h i l t bj d i l u k h i l n so t r y c t i l p vd phan m I m Idp trinh, qua dd giup cac can bd ky thudt t i l p tyc nghien c u u cac trinh t y d i l u k h i l n t i l t kigm nang lug'ng khdc d l dp d y n g cho cdc hg thdng ky thugt cua Cdng trinh Lang Chij tjch Ho C h i Minh nhdm tiet kigm dign nang tieu thy cua cdc hg thong ndy.
T a i l i e u t h a m k h a o
[1] Honeywell Engineering Manual of Automatic Control for Commercial Buildings, Honeywell Inc, 1977;
[2] Building control systems, CIBSE Guide H,2000;
[3] Fundamentals of HVAC Control Systems". American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 1791 Tuflie Circle, NE, 2008
Phan bien: TS Nguyen Vi^tDOng
