Đánh giá hiệu quả tiết kiệm điện của hệ thống cung cấp nước nóng có sử dụng bộ thu nhiệt mặt trời ở các tỉnh phía bắc

DANH GIA HIEU QUA TIET KIEM DIEN CUA HE THONG CUNG CAP Nl/dC NONG CO SLf DUNG BO THU NHIET MAT TROI 6 CAC TJNH P H I A BAC rs Le Nguyen Minh Vidn Khoa hgc vS Ky thuSt Mdi trudng Trudrng Dai hgc XSy du[.]

DANH GIA HIEU QUA TIET KIEM DIEN CUA HE THONG CUNG CAP Nl/dC NONG

CO SLf DUNG BO THU NHIET MAT TROI 6 CAC TJNH P H I A BAC

rs Le Nguyen Minh

Vidn Khoa hgc vS Ky thuSt Mdi trudng Trudrng Dai hgc XSy dung

Tdm tit: SCr dung bp thu nhipt mSt trdi trong hp thdng eung eip nude ndng d cac

tinh phia bic cd thi glim dugc tren 60% tidu thij dipn hSng nSm so vdi khi eip

nude ndng bing dipn Do diiu kipn bUc xa mSt trdi vSo eSc thSng miia ddng kha

thip (<3 kWh/nf/ngSy) nen hd thdng bp thu nhidt mSt trdi phai ed thiit bj cip nhidt

bi sung Thdi gian boSn vdn cho hp thdng cung cap nudc ndng cd sCr diing bp thu

nhidt mSt trdi vao khoang 5 - 6 nSm

Summary: Solar collector using in warm water system ean reduce about 60%

electric consumption per year Solar collector system must combine with an

addition heater because of low solar radiation in winter (<3kWh/m^/day)

Investment return rate for solar collector system is about 5-6 years

I D A T V A N D E

Odng trudc su can kief cac ngudn nhidn lieu vP finh trang P nhiem moi trudng thi vipe tang

cudng sd dung cdc ngudn nang lupng tai tao IP giai phap hpp ly cho su phat triln ben viimg Bdc

xa mat trdi (BXMT) v i n ludn la ngudn nang IUpng cdn bd ngd va sd dung kem hieu qua cho cdc

muc dich; cung cap nude ndng, dieu hod khdng khi, cung cap didn nPng

Nguydn nhdn chinh eda finh trang ndi trdn la do cudng dp bdc xa frung binh frdn mat ddt tupng dd'i nhd, chi vdo khoang 360 kcal/m^/h (Ha Ndi) vd sif biln ddng khdng phu hpp vdi ydu

cau eda ngudi sd dung Chinh vi vay, sd dung thiet bi thu BXMT cho muc dich ddn dung ngodi van de gia thanh la van de thie't bj BXMT cd thifc sif hidu q u i va dap dng dupe ydu cau tidn ghi eho ngudi sd dung hay khdng Trong pham vi bai bPo tac gia dua ra va phan tieh nhdng sd lipu

BXMT CO ban nha't trong viec tinh loan he thd'ng cung cap nude ndng ed sd dung bp thu nhipt mat trdi d cac linh phia Bac

2 PHUONG PHAP D A N H GlA TIEM N A N G CUNG CAP NHIET B A N G BO THU NHl|T M A T TROI 6 CAC TJNH PHI'A B A C

2,1 So lieu burc xa mat trdi vdng khu vuc Ha Npi

o l xdy dung phuong phap xac dinh tiem nang sd dung BXMT trong hp thdng cung cdp nudc ndng chung ta cd t h i sd dung sd lieu BXMT d khu vuc HP Ndi, ddi vdi cac vdng khi hau khdc ed t h i tinh loan tuong tu

42 TAP CHf KHOA HOC C 0 N G N G H $ X A Y DUNG Sd04/2009

Bang 1 So gid nhipt dp khdng khi theo cSe cap vS tdng bUe xa tren mat bang - Ha Npi

TCVN 4088:1985

ThSng

1

2

3

4

5

6

7

8

9

10

11

12

Nhidt dp khdng khi Sdgid theo cap nhipt dp CC)

- 5 < 10

7.2 19,1

0,6 16,8

< 15

314,9 242,1 58,0 1,5

0,2 35,4 165,7

<20

613,5 494,9 360,2 92,9 3,6

1,8 51,4 252,7 522,6

<25

732,8 660,0 698,2 473,8 162,7 54,0 35,2 46,9 121,5 418,6 615,5 718,2

<30

744 677,7 743,4 704,0 602,7 515,7 511,8 575,2 617,8 718,9 716,5 744,0

BUe xa mSt trdi Ting bUe

xa ngSy (kWh/m^/ngSy)

2877

3350

3561

4812

4696

5391

5788

5544

4871

4073

3555

3030

Tong bUc xa hipu diing (kWh/m'/ngay) Vdil>300W/m'

2,75 3,46 3,84 5,14 4,88 5,58 6,32 5,84 5,15 4,14 3,70 2,98 Qua bang sd lieu tren cd I h l tha'y:

- vao thang 1, 2, 3 va 11, 12 khi nhiel dp khdng khi xud'ng dudi 15°C thi ting nang lupng bdc xa mat trdi trong ngay cung cd gia Iri thdp, ch? IP 2,75 3,84 kWh/m^/ngPy

Trong cac thang noi tren thi thang 1 vP thang 12 co sd gid nhiet dp khdng khi l^^< 10°C

nhieu nhdt vP thang 1 cd long bdc xa ngPy thap nhdt (2877 keal/m^/ngay)

Vi vpy cd t h i chpn dieu kien khi hau bdt Ipi nhat vPo thang 1 d l tinh toan sd dung bdc xa mat trdi cho vide cung cd'p nude ndng d khu vifc Ha Ndi Td bang 1 va sd lieu bdc xa TCVN

4088 fa cd phan bd cUdng dp bde xa theo gid trong ngPy eda thang 1 va thang 7 dudi dang

bang vP do thj (hinh 1)

2.2 Hieu s u i t bo thu nhiet mdt trdi

o l ndng cao hipu sud't thu nhidt, bp thu nhidt mpt trdi thudng dupc che tao theo kilu hipu

img Idng kinh co Idp hdp thu bdc xa ehpn Ipc (loai 3) de giam ton that nhiet d bdc xa sdng dPi, hope kilu d'ng chan khdng (loai 4) de giam ton that fruyen nhidt Theo Din 4745 thi bp thu nhiet

hdp thu bdc xa chpn lpc loai 3 cd he sd hap thu 97%, he sd ton thdt bde xa 9% vd bd thu nhipl d'ng thuy linh ehan khdng cd he sd hap thu 93%, he sd ton that bdc xa 6% Hieu suat bd thu nhiet riK Phu thupc vao loai bp thu nhiel va hieu sd nhiet dp nudc ra - vao (At = I, -1^) dupc bilu dien trdn hinh 2

Dua vdo dd thi dpc tuydn cda cac loai bp thu nhipt, khi chpn dp chenh nhipt dp ra/vPo bd

thu nhidt Af = f« - f, ='iQKvS cUdng dp bde xa I - 400 W/m^ thi hieu suit cd f h l dat dupc rji^ =0,5 ddi vdi bpfhu nhidt hP'p thu chpn lpc 1 Idp kinh (loai 3) vP rj^ =0,6 dd'i vdi bdthu nhiet

dng thuy finh chdn khdng (loai 4)

TAP CHf KHOA HOC C O N G NGHg XAY DUNG Sd04/2009 43

sd lipu eudng dd birc

h

T h i r q l

TttingVli

0-7

—

7.8

xa 1

S-9

—

481

> 300 W/nr

9-10

370

712

10-11

474

872

thang

11-1212-1313-14

523

928

516

921

478

858

vS thSng 7

14-1515-16

390

729

—

534 16-17

297

- HS Ndi TCVN 4088

17-24 COng (kWlVngayl

2 7 5

6,33

Hinh 1 Bing vS dd thj tong BXMT eCia mpt ngSy thang 1 - HS Npi

vS tidu dung nude ndng (Q„,j cho 1 ngudi trong mpt ngSy

Hinh 2 Dudng dac tinh va pham vl ap dt/ng cua cac loai bp thu nhipt mSt trdi

Loai 1 Bp thu nhipt phing ling kinh 11dp:

Lo^i 2 Bp thu nhidt phing ldng kinh 2 ldp; Loai 3 Bp thu nhipt hap thu chgn Igc 11dp kinh:

Loai 4 Bp thu nhipt dng thiiy tinh chSn khdng

Td nhOmg gid tri hipu suat bd thu nhidt cd I h l xdc dinh dupe hieu qua thu nhiet trong 1

ngPy mda lanh thang 1 fai Ha Npi nhusau;

Qn /„ = 2,75jr0,5 = 1.375 kWh/m^/ngPy - bp thu nhiet loai 3

Qi, i«, = 2.'75JCO,6 = 1,65 kWh/m^/ngay - bp thu nhiet loai 4

VPo mda he khi eUdng dp bdc xa trung binh dat gia frj fd 4,14 -r 6,32 kWh/m^/ngay, thi td

1m^ bp thu nhipt mpt trdi loai 4 cd f h l thu dupe: 2,7 ^ 4,1 kWh/m^/ngay

2.3 Danh gia kha nPng cung cap nhiet ciia bp thu nhiet mat trdi

- Neu so sanh lupng nhiel thu dupc cda 2 loai bd thu nhiel ndi tren d dieu kipn BXMT bat

Ipi nhdt cua thang 1 thi td 1,5 m^ bp thu nhiet mpt trdi cd the dap img dupc nhu cau sd dung

nudc ndng cua 1 ngudi vao nhiJmg thdng mua lanh (khoang 1,80 kWh/ngPy luong duong 70/

nudc 34°C) Neu hp gia dinh cd nhieu ngudi Ihi phai bo sung binh dun dien 2,5 kW d l bu vao sif

thidu hut cdng sudt cda bp thu nhiel vdo ede thPng mda lanh

- vao 4 thang mda ddng cdn lai (thang 2, 3, 11, 12) do cudng dp bdc xa Idn hon nen kha

nang eung cdp nudc ndng cda cac bd thu nhiet tang dupe 25%

Trong thdi gian td thang 4 10 thi 1,5 m^ bd thu nhiel mat trdi cd f h l eung cdp td 4,0

-6,0 kWh/ngay, gid frj nay Idn hon nhieu cdng sud't can thief cho vide cung cap nudc ndng hang

ngdy cda hd gia dinh 3 ngudi (1,2 -1,5 kWh/ngPy)

3 GlAl PHAP THIET KE HE THONG CUNG CAP NU6C NONG CO sU DUNG BO THU

NHI|T M A T TRdi

Qua cPc sd lidu va phan tich d tren thi he thd'ng cung cap nudc ndng d khu vifc HP Ndi ed

sd dung Bd thu nhidt mpt trdi phai dupc thief ke theo dieu kien bde xa mpt trdi thdp nhat vdo

thang 1 Odi vdi hd gia dinh 3 - 6 ngUdi, khach san, benh vien de'n 500 giudng d l bo sung

lupng nhipt cdn thie'u cda cac bd thu nhiet mpt trdi vao cdc thdng mda ddng, ngudi ta cd I h l dau

ndi lilp binh dun dipn hope bom nhiel vao he thd'ng cung cap nude ndng, tuy thupc vPo quy mP

cdng suit cua he thd'ng

Bang 2 cho bilt cac thdng sd ky thudt eo ban cda bd thu nhiet mpt trdi, binh dun dien vd

bom nhidt I p dung trong giai phap thilt ke he thdng cap nudc ndng ed sd dung bp thu nhipt mat

trdi cho cae tinh phia Ble

o l dam bao ydu cau sd dung nude ndng khi dieu kidn bde xa mpt trdi khdng thudn Ipi vdo

c i c thing 1, 2, 3 vd 11, 12 trong nPm, ngoai bp thu nhidt mpt trdi he thdng phai ed ngudn nhidt

hd trp nhu sau;

- Gdi vdi hd gia dinh 3 ngudi cd the sd dung binh dun didn bo sung 2,5 kW

- Odi vdi hp thd'ng cd yeu cau sd dung nude ndng nhieu hon (khaeh san, bdnh vien, nhd

tre ) ndn sd dung bom nhidt IP loai thie't bj cd chi sd hieu qua nPng lupng tdt nhd't hipn nay

TAP CHf KHOA HOC C O N G N G H $ XAY DUNG sd04/2009 45

Bang 2 Thdng sd ky thuat ca ban cua bp

didn, bam

thu nhidt mSt trdi loai ong chSn khdng vS binh dun nhidt (Heat pump)

Thdng sd ky thuat

Bd thu nhipt mSt trdi loai dng chSn khdng Sunny 15

dng (1,5 m')

New Sun

100 ong (11,5 m')

Binh dun didn -ARISTON

301

Bam nhipt - Media

MGH-F175W/S MGH -F351V/S

Cong sudt nhipt

(tinh cho mda lanh) 2,48 kW 18,98 kW 2,46 kW 17,5 kW 35,0 kW

Luu lupng nudc

1000//

so-c

60//h 60°C

500 Ilh

60°C

1000 lib

60°C Thdi gian gia nhiet

T u ddng ddng/cit

T u dpng ddng/cIt

02 he thd'ng cung cdp nude ndng sd dung bd thu

Oieu khien nhiet do Tu dpng

Ket qua tinh loan liet kiem dien eho

nhiet mpt trdi cho trong bing 3

Bang 3 Tinh toSn tiit kidm dipn cho 02 hp thing cung cap nudc ndng

sCrdung bp thu nhipt mSt trdi

He thdng cung

eip nude ndng

HP gia dinh 3

ngudi;

- PA.1: Binh dun

didn:

- PA.2; Bp thu

nhipt mpt trdi vP

Binh dun didn

Bdnh vipn 200

gii/dng

-PA.1; Binh dun

dipn;

- PA.2; Bd thu

nhidt mpt trdi va

Bom nhipt:

Bpthu nhipt mSt trdi

0

1,5 m^

0

50 x 1,5m'

Binh ChUa

3 0 /

120/

200x

3 0 / 3000/

Bpdun dipn

2,5 kW

2,5 kW

200x 2,5 kW

0

Bam nhipt

0

0

0

2x17,5 kWh

Tidu thtj didn Mua

ddng

820 kWh

445 kWh

54720 kWh

9234 kWh

Mua hd

256 kWh

OkWh

17040 kWh

0

Tiit kipm tiin dipn hSng nSm (VND/nSm)

(PA.1-PA.2)

X 1600d/kWh'

= 1 009 600 d/nPm

(PA.1-PA.2)

X 945 d/kWh"

= 59 087 OOOd/nam

Ghi chir ' Gid dipn tinh luy tiln cho hp gia dinh 1600 d/kWh

* * G i l dien trung binh cho benh vipn 945 d/kWh

Hinh 3 gidi thieu so dd he thdng cung cap nude ndng eho hd gia dinh 3 - 4 ngudi cd sd dung binh dun dien bo sung > 2,5kW

46 TAP CHf KHOA HOC C O N G N G H $ X A Y DUNG Sd04/2009

MAITROl

Mua ddng;

+ V I : mcl, V2 dong + B B e ; 0 N Mua he:

+ V1 : dong, V2 md + BeO :OFF

Hinh 3 Sa dd hp thing cung cap nude ndng hp gia dinh 3-4 ngudi sCr dt/ng

bp thu nhidt mSt trdi vS binh dun didn 2,5 kW

NUOCCJSP

MUA DONG C(i BXMT V3 VI B 6 N G V2 M(J -KH6NGC6BXMT V 1 V 2 0 ( 5 N G V 3 M 6

BOM NH|£T O N

M U A H £

- V I M f l V2.V3EX5NG

BOM NHlfr OFF

BOM CA> Nl/OC

N O N G M N H 25O0UH

-//-Hinh 4 Sa dd hp thing eung eip nude ndng bpnh vidn 200 giudng

bao gdm 75m' bp thu nhipt mSt trdi vS 02 bam nhipt 17,5kW

3 NHAN XET VA KET LUAN

Trong d i l u kidn BXMT d cae tinh phia b l e vdo cac thang 1, 2, 3 vd 11, 12 hd thdng cung d p nude ndng sd dung bd thu nhidt mat trdi lopi dng chdn khong dat nPng suit cung d p nhidt khoing 2,40 kWh/ngdy Gia frj nay Idn hon yeu d u sd dung nudc ndng hPng ngdy cda 1 ngudi khoang 70/ d 34°C (1,8 kWh/ngdy)

- Vdo nhiJmg ngdy khdng cd ning thi binh dun didn vd bom nhidt phai cung d p 100% edng sud't nhidt

Tidu thu didn cda hd thd'ng cung d p nUdc ndng bao gdm 1,5 m' bp thu nhipt mpt trdi vd

binh dun didn so vdi phuong dn chi sd dung binh dun dien giam dugc 630 kWh/nam (58%)

- Odi vdi bpnh vidn 200 giudng sd dung bp thu nhidt mpt trdi vd bom nhidt fhi hidu qua tilt kidm diPn cao hon phuong an sddung binh dun dipn thPng thudng 87% (71760 kWh/nam)

- Nhin Chung khi sd dung bd thu nhiet mpt trdi trong he thd'ng eung d p nUde ndng d khu vuc Ha Npi thi cd the liel kiem dupc tren 60% lieu Ihu dien hPng nam nhung do gia thPnh cda

bp thu nhiel mpt trdi va bom nhiet kha eao nen thdi gian hoan vd'n phai td 5 - 6 nam da han chd sif ap dung rpng rai ngudn nang lupng tai tao dang bj bd ngd

Tai lieu tham khio

1 TCVN 4088:1895 - Tuyin tSp TCXD Vipt Nam Nxb XPy dung Ha Npi, 1997

2 Nikolai.V.Khart Chenko, Thermische Solaranlagen - Springer - Veriag Berlin Heidelberg New

York, 1995

3 Neues zum Thema Solateehnik, Wolf GmbH - Mainburg, 1995

4 Hans - Martin Henning (Ed), Solar - Assisted Air - conditioning in Buildings - Springer Wien

New York, 2004

48 TAP CHf KHOA HOC CONG NGHg XAY DUNG Sd04/2009