KiÕn tróc thÝch øng khÝ hËuv× sù ph¸t triÓn bÒn v÷ng ®Êt níc vµ khu vùc:

Ph¬ng ph¸p tiÕp cËn sinh khÝ hËu trong kiÕn tróc

Ph¹m §øc Nguyªn, §HXD Hanoi , TrÇn §×nh H¹, Tæng Héi X©y dùng VNB¸o c¸o t¹i B¸o c¸o t¹i Héi nghÞ lÇn thø 4 CECAR, Taipei 2007.

ViÖt Nam lµ mét trong h¬n 180 quèc gia trªn thÕ giíi tham gia C«ng íc Khung cña Liªn hîp quèc vÒ BiÕn ®æi khÝ hËu ký kÕt trong Héi nghÞ Thîng ®Ønh cña Liªn hîp quèc vÒ m«i trêng vµ ph¸t triÓn t¹i Rio de Janeiro, Brazil th¸ng 6/1992. ChÝnh phñ ViÖt Nam còng ®· ký phª chuÈn NghÞ ®Þnh th Kyoto do c¸c bªn tham gia C«ng íc th«ng qua vµ ®· cã c¸c Ch¬ng tr×nh hµnh ®éng quèc gia ®Ó thùc hiÖn NghÞ ®Þnh nµy, nh kiÓm kª quèc gia lîng ph¸t th¶i khÝ nhµ kÝnh, dù b¸o l-îng ph¸t th¶i trong t¬ng lai, ®Ò ra c¸c chiÕn lîc, chÝnh s¸ch ®Ó gi¶m lîng ph¸t th¶i, x©y dùng c¸c dù ¸n theo “C¬ chÕ ph¸t triÓn s¹ch”. KhÝ nhµ kÝnh cã nång ®é lín nhÊt trong khÝ quyÓn lµ Carbon dioxide (CO2), cã nguån gèc chñ yÕu tõ ®èt nhiªn liÖu ho¸ th¹ch ®Ó s¶n xuÊt ®iÖn n¨ng phôc vô con ngêi. T¹i NhËt B¶n, theo «ng Katashi Matsunawa, G§ Nikken Sekkei Tokyo, lîng ph¸t th¶i CO2 do c«ng nghiÖp chiÕm 64%, 36% cßn l¹i lµ do nhµ d©n dông. N¨ng lîng sö dông trong c«ng tr×nh x©y dùng, bao gåm tõ s¶n xuÊt vËt liÖu, cÊu kiÖn x©y dùng, thi c«ng l¾p ®Æt ®Ó hoµn thµnh x©y dùng c«ng tr×nh, kÓ c¶ lóc söa ch÷a, ph¸ bá, nhng lín nhÊt lµ n¨ng lîng ®Ó vËn hµnh, khai th¸c trong suèt cuéc ®êi mét c«ng tr×nh. Theo sè liÖu cña Tæng c«ng ty ®iÖn lùc ViÖt Nam, tû lÖ ®iÖn n¨ng tiªu thô n¨m 2001 ë ViÖt Nam nh sau: n«ng nghiÖp 1,8%, c«ng nghiÖp 40,66%, th¬ng m¹i, kh¸ch s¹n 4,84%, ¸nh s¸ng sinh ho¹t 48,94% ¸nh s¸ng giao th«ng 3,76%. Trong phÇn ®iÖn n¨ng tiªu thô cho c«ng nghiÖp cã c¶ phÇn s¶n xuÊt vËt liÖu, cÊu kiÖn x©y dùng vµ thi c«ng x©y dùng c«ng tr×nh, v× vËy tæng n¨ng lîng dïng trong c«ng tr×nh x©y dùng sÏ chiÕm kho¶ng 60% tæng n¨ng lîng tiªu thô cña quèc gia. Tr¸ch nhiÖm ®ãng gãp cña ngµnh x©y dùng vµo sù ph¸t triÓn bÒn v÷ng cña ®Êt níc, cña khu vùc vµ cña toµn cÇu, lµ ph¶i x©y dùng ®îc c¸c c«ng tr×nh cã kh¶ n¨ng tèi ®a sö dông n¨ng lîng tù nhiªn, gi¶m bít sö dông n¨ng lîng ho¸ th¹ch. Muèn ®¹t ®îc ®iÒu nµy, c«ng tr×nh x©y dùng cÇn ph¶i thÝch øng víi khÝ hËu ®Þa ph¬ng. Hµnh ®éng theo híng nµy, chóng t«i ®· x©y dùng mét ph¬ng ph¸p tiÕp cËn míi vµo khÝ hËu khi thiÕt kÕ vµ x©y dùng c«ng tr×nh, gäi lµ “ph¬ng ph¸p tiÕp cËn sinh khÝ hËu”. Theo ph¬ng ph¸p nµy cã thÓ ®Ò xuÊt c¸c chiÕn lîc thiÕt kÕ kiÕn tróc c«ng tr×nh thÝch øng nhÊt víi

1

khÝ hËu ®Þa ph¬ng trªn c¬ së hiÓu biÕt s©u s¾c ¶nh hëng cña c¸c d¹ng thêi tiÕt trong khÝ hËu mçi ®Þa ph¬ng tíi con ngêi. Ph¬ng ph¸p nµy kh«ng ph¶i lµ míi trªn thÕ giíi, vÝ dô nã ®· ®îc nghiªn cøu ¸p dông ë Mü [1], nhng lµ lÇn ®Çu tiªn ®îc x©y dùng ë ViÖt Nam. Cã thÓ coi hµnh ®éng nµy nh mét “dù ¸n thùc hµnh c¬ chÕ ph¸t triÓn s¹ch trong x©y dùng” theo ph¬ng híng cña NghÞ ®Þnh th Kyoto.

Ph¬ng ph¸p tiÕp cËn sinh khÝ hËu vµ BiÓu ®å sinh khÝ hËu x©y dùng ViÖt Nam

Ph¬ng ph¸p thiÕt kÕ kiÕn tróc khÝ hËu truyÒn thèng ë ViÖt Nam tr-íc ®©y lµ:

(i) Tiªu chuÈn ho¸ c¸c gi¸ trÞ trung b×nh cña th«ng sè khÝ hËu ngoµi nhµ (bøc x¹ mÆt trêi, nhiÖt ®é, ®é Èm, vËn tèc vµ híng giã) trong mïa nãng vµ mïa l¹nh.

(ii) ThiÕt kÕ vá nhµ b»ng c¸c gi¶i ph¸p kiÕn tróc khÝ hËu.(iii) X¸c ®Þnh c¸c th«ng sè cña vi khÝ hËu (VKH) trong nhµ vµ

®¸nh gi¸ møc ®é tiÖn nghi cña nã.(iv) §iÒu chØnh l¹i vá nhµ nh»m ®¹t ®îc m«i trêng VKH tiÖn nghi.Ph¬ng ph¸p nµy gäi lµ “ph¬ng ph¸p tiÕp cËn vi khÝ hËu” vµ ®îc m« t¶ trªn h×nh 1.

KhÝhËu ngoµi nhµ(tr Þ sè tr ung b×nh theoTCVN 4088-85, ho¨c theo hÖ sè b¶o ®¶m)

c«ng tr ×nh kiÕn tr óc

Vi khÝhËu• NhiÖt®é bÒmÆtphßng• §é Èm• NhiÖt®é kh«ngkhÝ• VËntèckh«ngkhÝ

Gi¶I ph¸p kiÕn tr óc khÝ hËu:-C ch nhiÖt - che n¾ng, t¹ o bãng - th«ng giã tù nhiªn, c¬khÝ- c©y xanh,mÆt n í c

Ph ¬ngph p tiÕp cËn vikhÝhËu

H×nh 1. Ph¬ng ph¸p tiÕp cËn vi khÝ hËu

Ph¬ng ph¸p tiÕp cËn vi khÝ hËu tuy cho phÐp thùc hµnh thiÕt kÕ kiÕn tróc kh¸ dÔ dµng, nhng cã nhîc ®iÓm c¬ b¶n lµ thiÕu c¬ së ®Ó ®Ò xuÊt c¸c chiÕn lîc thiÕt kÕ kiÕn tróc thÝch øng nhÊt víi khÝ hËu mçi vïng. V× vËy chóng t«i ®Ò xuÊt “ph¬ng ph¸p tiÕp cËn sinh khÝ hËu” díi ®©y (h×nh 2):

2

(i) Ph©n tÝch khÝ hËu ngoµi nhµ trong ¶nh hëng cña nã tíi con ng-êi theo c¶m gi¸c nhiÖt cña ngêi ViÖt Nam: ph©n tÝch sinh khÝ hËu.

(ii) X¸c ®Þnh (theo % sè giê/n¨m) xuÊt hiÖn c¸c d¹ng thêi tiÕt theo c¶m gi¸c nhiÖt kh¸c nhau ®Ó ph©n lo¹i sinh khÝ hËu ®Þa ph-¬ng.

(iii) X¸c ®Þnh c¸c chiÕn lîc thiÕt kÕ kiÕn tróc thÝch øng víi c¸c lo¹i thêi tiÕt/ khÝ hËu sinh häc cã tÇn suÊt xuÊt hiÖn lín nhÊt t¹i ®Þa ph¬ng.

(iv) §Ò xuÊt c¸c gi¶i ph¸p thiÕt kÕ cô thÓ theo mçi chiÕn lîc.

Ph ¬ngph ptiÕpcËnsinhkhÝhËutrongkiÕntrócthÝchøngkhÝhËu

KhÝhËungoµinhµ

Ph©ntÝchSinhkhÝhËu

ChiÕnl î cthiÕtkÕkiÕntróc

L¹ nh

NãngÈm

Nãngkh«

Gi¶Iph pkiÕntróckhÝhËut ¬ng

øng

H×nh 2. Ph¬ng ph¸p tiÕp cËn sinh khÝ hËu

§Ó lµm c¬ së ph©n tÝch sinh khÝ hËu c¸c ®Þa ph¬ng, chóng t«i ®· x©y dùng ®îc “BiÓu ®å sinh khÝ hËu x©y dùng” cho ngêi ViÖt Nam (B§SKHXD) (building bioclimatic chart) nh trªn h×nh 3, nhê tiÕp thu c¸c nghiªn cøu vÒ c¶m gi¸c nhiÖt cña con ngêi do c¸c t¸c gi¶ ViÖt Nam ®· thùc hiÖn tríc ®©y (theo ph¬ng ph¸p vi khÝ hËu) sau khi ®· tiÕn hµnh thªm c¸c thùc nghiÖm kiÓm chøng. BiÓu ®å ®· xÐt ®Õn t¸c ®éng ®ång thêi cña nhiÖt ®é, ®é Èm, vËn tèc giã, møc ®é ho¹t ®éng (metabolism) vµ ¸o quÇn tíi c¶m gi¸c nhiÖt cña con ngêi. (BiÓu ®å nµy ®· ®îc nghiÖm thu trong khu«n khæ ®Ò tµi NCKH thùc hiÖn ë cÊp Bé X©y dùng ViÖt Nam n¨m 2002-2004 [2,3]).

3

H×nh 3. B§SKHXD ViÖt Nam (1 met)

ChÝn vïng c¶m gi¸c nhiÖt – vïng sinh khÝ hËu (vïng SKH) - trªn B§SKHXD lµ:Vïng 1- RÊt l¹nh (RL); vïng 2 - L¹nh (L); vïng 3 - L¹nh võa (LV); vïng 4 – Giíi h¹n tiÖn nghi (TN) tÝnh tõ c¶m gi¸c h¬i l¹nh ®Õn c¶m gi¸c h¬i nãng; vïng 5 - M¸t kh« (MK)- m¸t nhng ®é Èm rÊt thÊp (díi 20%); vïng 6 - M¸t Èm (MA) )- m¸t nhng ®é Èm rÊt cao (trªn 90%); vïng 7 - Nãng (N); vïng 8 - RÊt nãng Èm (RNA) vµ vïng 9 - RÊt nãng kh« (RNK). Thêi tiÕt c¸c vïng 3, 4, 5, 6, 7 nãi chung cã thÓ më cöa ®ãn kh«ng khÝ tù nhiªn, khi cÇn cã thÓ sö dông biÖn ph¸p xö lý bæ sung. Vïng 1, 2, 8 vµ 9 cÇn cã ®iÒu hoµ nh©n t¹o. Theo kh¶o s¸t thùc tÕ, trªn toµn l·nh thæ ViÖt Nam kh«ng xuÊt hiÖn c¸c thêi tiÕt vïng 5 vµ 9.

Ph©n tÝch sinh khÝ hËu c¸c ®Þa ph¬ng ViÖt Nam C¸c sè liÖu khÝ hËu tõ c¸c tr¹m quan tr¾c khÝ hËu ®Þa ph¬ng ®îc lÊy ®ång thêi c¶ nhiÖt ®é kh«ng khÝ vµ ®é Èm theo mçi giê/ mçi ngµy trong 20 n¨m (1981-2000) ®îc ph©n tÝch trªn B§SKHXD ®Ó x¸c ®Þnh tÇn suÊt/n¨m xuÊt hiÖn theo c¸c vïng SKH. §· tiÕn hµnh ph©n tÝch SKH cho 10 ®« thÞ ViÖt Nam. Trªn h×nh 4 giíi thiÖu lµm vÝ dô c¸c B§ ph©n tÝch SKH cña thµnh phè §µ N½ng theo % sè giê xuÊt hiÖn/ n¨m vµ ®êng biÕn thiªn trung b×nh mçi th¸ng.

4

H×nh 4. Ph©n tÝch SKH §µ N½ng (vÜ ®é 16,02oB;kinh ®é 108,12o§; cao ®é 3 m)KÕt qu¶ ph©n tÝch so s¸nh SKH x©y dùng 10 ®Þa ph¬ng ViÖt Nam giíi thiÖu trªn b¶ng 1. Tõ kÕt qu¶ nµy cã thÓ rót ra nh÷ng ®¸nh gi¸ chÝnh x¸c c¸c d¹ng thêi tiÕt sinh häc kh¸c nhau cña mçi ®Þa ph¬ng. B¶ng 1. Ph©n tÝch SKH 10 ®Þa ph¬ng ViÖt Nam Vïng SKH 1:RL 2:L 3:LV 4:TN 5:M

K6:M

A7:N 8:RN

A9:RNK

Hµ Giang 0 9,00

24,88

41,29

0 24,21

0,62 0 0

§iÖn Biªn 0 11,05

21,15

45,51

0 22,29

0 0 0

H¹ Long 0,6 8,23

19,27

49,21

0 20,27

2,42 0 0

Hµ Néi 0,6 8,6 18 44,6 0 23,4 4,5 0,3 0Vinh 0,2 5,4 18,7 42,0

10 28,6

44,9 0,15 0

§µ N½ng 0 0 4,53 85,42

0 8,85 1,20 0 0

Bu«n ma thuét

0 0,3 10,7 59,1 0 29,3 0,6 0 0

Nha Trang 0 0 0 99,08

0 0,58 0,34 0 0

Hå ChÝ Minh

0 0 0,2 79,5 0 16,7 3,5 0,1 0

CÇn Th¬ 0 0 0 61,45

0 38,53

0,02 0 0

X¸c ®Þnh c¸c chiÕn lîc thiÕt kÕ kiÕn tróc thÝch øng khÝ hËuChiÕn lîc thiÕt kÕ kiÕn tróc thÝch øng khÝ hËu lµ ph¬ng híng chung ®Ó chØ dÉn thiÕt kÕ vÒ quy ho¹ch ®« thÞ vµ kiÕn tróc c«ng tr×nh, dùa trªn c¸c c¬ së khoa häc cña kiÕn tróc – khÝ hËu – con ngêi. Tõ mçi chiÕn lîc

5

cã thÓ ®Ò xuÊt nhiÒu gi¶i ph¸p cô thÓ vÒ vÞ trÝ c«ng tr×nh, tæ hîp mÆt b»ng, mÆt ®øng, cÊu t¹o kiÕn tróc, vËt liÖu… ®Ó c«ng tr×nh phï hîp nhÊt víi khÝ hËu ®Þa ph¬ng. TiÕp thu c¸c kiÕn thøc vÒ kiÕn tróc khÝ hËu trªn thÕ giíi, chóng t«i tæng kÕt thµnh 15 chiÕn lîc thiÕt kÕ kiÕn tróc thÝch øng khÝ hËu nh trong b¶ng 2. Mçi chiÕn lîc sÏ thÝch hîp nhÊt víi mét vµi vïng SKH, ®îc ghi ë cét cuèi (®¸nh sè tõ 1 ®Õn 9). B¶ng 2. C¸c chiÕn lîc thiÕt kÕ kiÕn tróc thÝch øng khÝ hËu

STT

Tªn chiÕn lîc thiÕt kÕ

Gi¶i ph¸pVïng SKH ¸p

dông1 C¸ch nhiÖt b»ng khèi

nhiÖtDïng kÕt cÊu cã chiÒu dµy lín ®Ó t¨ng trë nhiÖt b¶n th©n R

1, 2, 3, 9

2 C¸ch nhiÖt tèt, th¶i nhiÖt nhanh

Dïng kÕt cÊu máng, nhiÒu líp, cã líp kh«ng khÝ, dïng vËt liÖu bøc x¹ m¹nh, vËt liÖu c¸ch nhiÖt ®Ó t¨ng trë nhiÖt b¶n th©n R

4, 6,7, 8

3 Thu nhiÖt BXMT VËt liÖu kÕt cÊu thu nhËn BXMT ®Ó sëi Êm phßng (ban ®ªm, mïa l¹nh)

1, 2, 5, 9

4 Gi¶m nhËn nhiÖt BXMT

Dïng vËt liÖu ph¶n x¹, bøc x¹ m¹nh, t¹o bãng, che n¾ng, híng nhµ thÝch hîp ®Ó gi¶m trùc x¹ chiÕu lªn kÕt cÊu

4, 6, 7, 8

5 Th«ng giã tù nhiªn Më réng cöa ®ãn giã, híng nhµ ®ãn giã m¸t, quy ho¹ch ®a giã vµo thµnh phè, khu nhµ, c«ng tr×nh

3*, 4 , 5*, 6*, 7, 8

6 Th«ng giã c¬ khÝ (qu¹t)

T¨ng v©n tèc giã b»ng thiÕt bÞ n¨ng lîng thÊp (qu¹t trÇn, qu¹t têng…)

4, 5, 6, 7, 8, 9*

7 Lµm m¸t b»ng bay h¬i níc

Sö dông nhiÖt Èn bay h¬i cña níc ®Ó lµm m¸t kh«ng khÝ chung quanh, t¨ng ®é Èm

5, 7, 9

8 Gi¶m BXMT trùc tiÕp vµo phßng

Che n¾ng cho cöa sæ, sö dông kÝnh ph¶n quang, kÝnh hót nhiÖt, kÝnh nhiÒu líp.

4, 5, 6, 7, 8, 9

9 Lîi dông nhiÖt ®é m«i trêng chung quanh (®Êt, níc, c©y xanh)

Gi¶m (mïa hÌ) hoÆc t¨ng (mïa ®«ng) nhiÖt ®é bªn ngoµi nhê lîi dông sù che chë hoÆc tÝnh chÊt lý ho¸ cña m«i tr-êng tù nhiªn, c©y xanh, s«ng níc

1, 2, 3, 7, 8, 9

10 §iÒu khiÓn ®é trÔ cña dßng nhiÖt

B»ng cÊu t¹o kÕt cÊu cã thÓ ®iÒu khiÓn thêi ®iÓm xuÊt hiÖn nhiÖt ®é cùc ®¹i trong nhµ lóc thÝch hîp

4, 5, 6, 7, 8, 9

11 Tr¸nh mÊt hoÆc nhËn nhiÖt qua khe hë, têng hoa

Tr¸nh giã l¹nh mïa ®«ng hoÆc mÊt nhiÖt khi sëi Êm hay ®iÒu hoµ nhiÖt ®é

1, 2, 3, 8*, 9*

12 Chèng ®äng s¬ng trªn T¨ng nhiÖt ®é mÆt trong kÕt cÊu cao 4, 6, 7,

6

bÒ mÆt trong nhµ (chèng nåm)

h¬n nhiÖt ®é ®iÓm s¬ng cña kh«ng khÝ trong phßng

8

13 Bøc x¹ m¸t Sö dông bÒ mÆt cã nhiÖt ®é thÊp ®Ó gi¶m nhiÖt c¬ thÓ, lµm m¸t

7, 8, 9

14 Bøc x¹ nãng Sëi Êm phßng b»ng bøc x¹ nhiÖt (lß sëi) 1, 2, 315 §iÒu hoµ khÝ hËu

nh©n t¹oDïng thiÕt bÞ nh©n t¹o gi¶m nhiÖt ®é, ®é Èm phßng

8,9

Ghi chó: DÊu (*) biÓu hiÖn chiÕn lîc ¸p dông cã ®iÒu kiÖn CÇn chó ý r»ng trong mét lo¹i khÝ hËu cã thÓ xuÊt hiÖn nhiÒu (hoÆc Ýt) vïng SKH kh¸c nhau vÒ tÇn suÊt. Do ®ã mét kiÓu khÝ hËu cã thÓ ¸p dông ®ång thêi mét sè chiÕn lîc thiÕt kÕ, nhng trong ®ã ph¶i cã c¸c chiÕn lîc ®îc u tiªn hµng ®Çu, t¬ng øng víi vïng SKH chiÕm u thÕ nhÊt. Chóng t«i ®· giíi thiÖu “ph¬ng ph¸p ma trËn lùa chän chiÕn lîc tèi -u” cho mçi kiÓu khÝ hËu. Tr×nh tù tiÕn hµnh ph¬ng ph¸p ma trËn nh sau:(1) Phèi hîp b¶ng 1 vµ 2, lËp b¶ng kh¶ n¨ng ¸p dông c¸c chiÕn lîc thiÕt kÕ sinh khÝ hËu cho ®Þa ph¬ng nghiªn cøu.

VÝ dô, b¶ng 3 lËp cho §µ N½ng. B¶ng 3. Kh¶ n¨ng ¸p dông c¸c chiÕn lîc thiÕt kÕ sinh khÝ hËu t¹i §µ n½ng

Vïng c¶m gi¸c nhiÖt

% thêi gian xuÊt hiÖn trong mét n¨m Gi¶i ph¸p kiÕn tróc khÝ hËu

1- RL 0 -2- L 0 -3- LV 4,53 5*, 9, 12 4- TN 85,42 2, 4, 5, 6, 8, 10, 5- MK 0 -6- MA 8,85 2, 4, 5*, 6, 8, 10, 13*7- N 1,2 2, 4, 5, 6, 8, 9, 10, 13 8- RNA 0 -9- RNK 0 -

(2) LËp b¶ng ma trËn: ph¬ng ngang ®Æt 9 vïng sinh khÝ hËu, ph¬ng däc xÕp 15 chiÕn lîc theo thø tù trong b¶ng 2. VÝ dô ë b¶ng 4 lËp cho TP §µ N½ng.(3) TÝnh ®iÓm cho c¸c chiÕn lîc cã thÓ ¸p dông: C¸c « trong b¶ng 4 (n¬i gÆp cña vïng SKH vµ chiÕn lîc ¸p dông) lµ sè ®iÓm tÝnh cho mçi chiÕn lîc cã thÓ ¸p dông, t¬ng øng víi tÇn suÊt xuÊt hiÖn trong b¶ng 1. C¸ch tÝnh ®iÓm: Mçi 1% tÇn suÊt ®îc tÝnh 1 ®iÓm, Khi chiÕn lîc ¸p dông cã kiÓm so¸t, chØ tÝnh 50% sè ®iÓm. ¤ kh«ng cã ®iÓm lµ chiÕn lîc kh«ng thÓ ¸p dông.

7

(4) X¸c ®Þnh chiÕn lîc u tiªn b»ng c¸ch tÝnh tæng sè ®iÓm cho mçi chiÕn lîc (tæng ®iÓm theo ph¬ng ngang). Sau ®ã xÕp thø tù u tiªn theo sè ®iÓm, tõ cao ®Õn thÊp. VÝ dô trong b¶ng 4 lµ lËp cho khÝ hËu TP §µ N½ng. B¶ng 4. X¸c ®Þnh c¸c chiÕn lîc thiÕt kÕ kiÕn tróc u tiªn cho TP §µ n½ng

CL TÝnh ®iÓm cho mçi CL theo vïng SKH Céng

®iÓmXÕp lo¹iRL L LV TN MA N RNA

1 0 0 0 0 0 0 0 0 -2 0 0 0 85,4

28,85 1,2 0 95,47 2

3 0 0 0 0 0 0 0 0 -4 0 0 0 85,4

28,85 1,2 0 95,47 2

5 0 0 4,53

85,42

4,42 1,2 0 95,57 1

6 0 0 0 85,42

8,85 1,2 0 95,47 2

7 0 0 0 0 0 0 0 0 -8 0 0 0 85,4

28,85 1,2 0 95,47 2

9 0 0 4,53

0 0 1,2 0 5,73 7

10 0 0 0 85,42

8,85 1,2 0 95,47 2

11 0 0 0 0 0 0 0 0 -12 0 0 4,5

30 0 0 0 4,53 9

13 0 0 0 0 4,42 1,2 0 5,62 814 0 0 0 0 0 0 0 0 -15 0 0 0 0 0 0 0 0 -

Tõ b¶ng 4 x¸c ®Þnh ®îc c¸c chiÕn lîc u tiªn trong thiÕt kÕ kiÕn tróc sinh khÝ hËu §µ N½ng nh sau:- u tiªn sè 1: ChiÕn lîc 5 (th«ng giã tù nhiªn)- u tiªn sè 2: C¸c chiÕn lîc 2, 4, 6, 8 vµ 10 (ngang nhau).C¸c chiÕn lîc kh¸c cã sè ®iÓm thÊp h¬n ®¸ng kÓ, nªn kh«ng quan t©m. Ph¬ng ph¸p ma trËn lùa chän chiÕn lîc u tiªn nªu trªn ®Æc biÖt cã gi¸ trÞ khi ¸p dông cho c¸c quèc gia cã nhiÒu kiÓu sinh khÝ hËu kh¸c nhau râ rÖt.

KÕt luËnCon ngêi sèng víi thêi tiÕt, cßn c«ng tr×nh kiÕn tróc tån t¹i trong khÝ hËu. Thêi tiÕt lu«n lu«n thay ®æi vµ t¸c ®éng trùc tiÕp tíi con ngêi. Nh-ng con ngêi lµ mét c¬ thÓ sèng, cã kh¶ n¨ng tù ®iÒu chØnh ®Ó thÝch

8

øng trong mét giíi h¹n thêi tiÕt kh¸ réng. C«ng tr×nh kiÕn tróc kh«ng thÓ lu«n lu«n thay ®æi (hoÆc chØ cã thÓ thay ®æi rÊt Ýt) ®Ó thÝch øng víi mçi d¹ng thêi tiÕt, nªn ph¶i phï hîp víi mét quy luËt chung cña thêi tiÕt t¹i khu vùc, nghÜa lµ thÝch øng víi khÝ hËu ®Þa ph¬ng. Ph¬ng ph¸p tiÕp cËn sinh khÝ hËu gióp ngêi thiÕt kÕ x¸c ®Þnh ®îc c¸c chiÕn lîc u tiªn ®óng ®¾n vµ thÝch øng nhÊt víi khÝ hËu. Tõ ®ã, b»ng kinh nghiÖm vµ tµi n¨ng s¸ng t¹o, ngêi thiÕt kÕ sÏ ®Ò xuÊt c¸c gi¶i ph¸p thiÕt kÕ quy ho¹ch vµ kiÕn tróc cô thÓ phï hîp nhÊt, b¶o ®¶m cho c«ng tr×nh hoµ hîp víi tù nhiªn, b¶o vÖ m«i trêng sinh th¸i khu vùc.

Tµi liÖu tham kh¶o chÝnh1- Donald Watson & Kenneth Labs. Climatic building Design - Energy-efficient building principles and practice.1992.2- B¸o c¸o ®Ò tµi “X©y dùng ng©n hµng d÷ liÖu phôc vô thiÕt kÕ kiÕn tróc nhiÖt ®íi”. RD 25-02. §Ò tµi NCKH Bé X©y dùng, n¨m 2002- 2003. Ph¹m §øc Nguyªn vµ céng sù.3- B¸o c¸o ®Ò tµi “ X©y dùng ng©n hµng d÷ liÖu khÝ hËu phôc vô thiÕt kÕ kiÕn tróc nhiÖt ®íi”. RD 42-04. §Ò tµi NCKH Bé X©y dùng, n¨m 2004- 2005. Ph¹m §øc Nguyªn vµ céng sù.

9

Climate-adaptive Architecture for country and region sustainable development:

Bioclimate approach method in Architectural Design Arch. Pham Duc Nguyen, Hanoi University of civil engineering

Arch. Tran Dinh Ha,VIFCEAAbstract Bioclimatic approach method helps designer to define strategies of architectural design most adapting local climate on the basics of understanding deeply influence of diverse forms of weather to the man.

Key words: microclimate approach method, bioclimatic approach method, Building bioclimatic chart, bioclimatic zones

Vietnam is one of 180 countries in the World participating the United Nations Framework Convention on climate change signed in United Nations Summit on Environment and Development in Rio de Janeiro, Brazil in June 1992. The Vietnam Government has also ratified the Kyoto Protocol approved by participating Convention parties and has had National action Programs to implement this Protocol. For exmples, greenhouses gases (GHG) inventories and forecast of GHG emissions in the future, formulating strategies, policies and action plans to decrease impacts of climate change, proposing projects of “Clean Development Mechanism”.GHG having the highest strenght in the atmosphere is carbon dioxide (CO2), which is derived mainly from giving fossil combustible to generate power energy for human life service. In Japan, according to Mr. Katashi Matsunawa, Nikken Sekkei Tokyo director, CO2 emissions from industry occupes 64%, the 36 % reminded of CO2 emissions are due to buidings, largely in the form of energy consumption. Energy used in construction works comprises of building materials production, building components production, execution and erection for completing project construction, including reparation, demolition, but the biggest one is energy for operation, exploitation during the building’s service life. According to Vietnam Electricity Corporation, the rate of power energy consumption in 2001 is as follows: Agriculture 1.8%, Industry 40.66%, Trade, Hotel 4.84%, living light 48.94%, traffic light 3.76%. Parts of building materials, building components production and project execution included in the part industrial consumption, therefore the energy used in construction work will occupe about 60% of country consumed total energy. The construction sector’s contribution responsibility in sustainble development of the country, the region and the world is have to build works, which have possibility of maximum utilization of natural energy, reducing fossil energy utilization. For reaching this goal, construction building has to adapt local climate. With this direction, we have set up a new approach method into climate during work design and building construction which is called “bioclimatic approach method”. By this method, it can propose strategies of architectural design most adapting local climate on the basic of understanding deeply influence of diverse forms of weather in climate to the man each locality.This method is not new one in the world, it has be studied in USA [1], but being the first time in Vietnam. This action can be see as a “project praticing clean development mechanism in construction” according to the direction of the Kyoto Protocol.

Bioclimatic approach method and building bioclimatic Chart for VietnameseTraditionally climate-architectural design method in Vietnam was:

(i) Standardizating average values of outdoor climate specifications (solar radiation, temperature, humidity, wind speed and direction …) in hot season and cold season .

(ii) Designing house skin by climate-architecture solutions.(iii) Defining indoor microclimate and evaluating its comfort condition.(iv) Adjusting house skin to reach the comfort condition of indoor microclimate.

This method called “microclimate approach method” and discribed in Figure 1.Although this microclimate approach method allow practicing architectural design rather easy, but its basic weakness is lacking basis to propose the adapted architectural design strategies to each climatic region. Therefore, we propose the following bioclimatic approach method (Figure 2).

(i) Analysing outdoor climate and its influence to man according to vietnamese heat sensation: Bioclimate Analysis.

10

(ii) Defining (by % hours/year) appearances of weather forms according to different heat sensation to classify bioclimate zone.

(iii) Defining architectural design strategies adapted kinds of weather forms which have the biggest appearance frequency in the locally.

(iv) Proposing concrete design solutions according to the each strategy.

Outdoor cl imateAver age val ues

Buil ding

micr ocl imate• Inside surface temperature• Humidity• Air temperature• Air flow speed

Cl imate-ar chitectur e sol utions--Insul ation – shading devices – natur al ventil at ion – radiant cool ing -

Microclimateapproach method

Bioclimatic approach method in architecture

Outdoor climate

Bioclimatic analisis

Architectural design

strategies Cold

Wet hot

Dry Hot

Climate-Architecture

adaptive solutions

Figure 1. Microclimate approach method Figure 2. Bioclimatic approach method

In order to create a basis of localities bioclimatic analysis, we have established “Building bioclimatic chart” for vietnamese (BBC), showed in figure 3 by assimilating studies of on human being heat sensation carried out in the past vietnamese authors (following microclimate method) and after carring out more verifitable experiments. The chart has examined parallel impact of temperature, humidity, wind speed, metabolism and clothes to human being heat sensation. This chart has been checked and taken over in the framework of scientific reseaching theme implemented at the grade of the Vietnam Ministry of Construction from 2002-2004 [2,3].

11

Figure 3. Building bioclimatic Chart for Vietnamese (1met)

Nine heat sensation zones – bioclimatic zones – of the BBC are as follows: zone 1: very cold (VC), zone 2: cold (C), zone 3: suited cold (SC), zone 4: comfort (CF), counting from rather cold sensation to rather hot sensation, zone 5: Dry- cool (DC)- it is cool but with very low humidity (under 20%), zone 6: wet - cool (WC) - it is cool but with very high humidity (over 90%), zone 7: Hot (H), zone 8: very wet- hot (VWH), and zone 9: very dry- hot (VDH). The weather of 3,4,5,6,7 zones it generally can open the window to receive natural air, when being needed it can utilize solution of supplementary treatment. 1, 2, 8, 9 zones need to make the climate equable artificially. According pratical survey in the whole Vietnam territorial there are no zones of heat sensation 5 and 9.

Bioclimatic analisis of Vietnam territorialClimate data from local observatories which are taken paralelly all air temperature and humidity by each hour/each day during 20 years (1981-2000) being analysed on BBC to define frequence/year appearing in bioclimatic zones. Ten cities of Vietnam have been analyzed bioclimaticly. The figure 4 taken as exemple of chart analysing Danang city bioclimate by % hour number of appearance/year.

Figure4. Analysing Danang bioclimate (latitude 16.02oN, longitude 108.12 E, height 3m)

Results of building bioclimatic analysis and comparison of 10 Vietnam cities showed in Table 1. It can derive from these results exact evaluations of each city biological weather different forms.

Table 1. Building bioclimatic analysis of 10 Vietnam citiesCities VC C SC CF DC WC H VWH VDH

Hagiang 0 9,00 24,88 41,29 0 24,21 0,62 0 0§iebien 0 11,05 21,15 45,51 0 22,29 0 0 0Halong 0,6 8,23 19,27 49,21 0 20,27 2,42 0 0

12

Hanoi 0,6 8,6 18 44,6 0 23,4 4,5 0,3 0Vinh 0,2 5,4 18,7 42,01 0 28,64 4,9 0,15 0

§anang 0 0 4,53 85,42 0 8,85 1,20 0 0Buonmathuot 0 0,3 10,7 59,1 0 29,3 0,6 0 0

Nha Trang 0 0 0 99,08 0 0,58 0,34 0 0HoChiMinh 0 0 0,2 79,5 0 16,7 3,5 0,1 0

Cantho 0 0 0 61,45 0 38,53 0,02 0 0

Defining climate- adaptive architecture design strategies Architectural design strategy adapted climate is a general direction to guide designer on urban planning and building architecture based on scientific basis of architecture – climate – human being. From each strategy it can propose diverse concrete solutions of works site, plan, facade organization, architectural composition, materials … so as the work can be most suited with the locallity climate.Assimilating knowledges of climatic architecture in the world, we sump up in 15 strategies of architectural design adapted climate as showed in table 2. Each strategy will be most suited with some bioclimatic zones which is noted at the last column (numbering from 1 to 9).

Table 2. Strategies of architectural design adapted climateNo Name of design strategy Solution Bioclimatic

zone1 Minimize conductive flow by

thermal mass Using structure with big thickness to increase self-thermal resistance

1, 2, 3, 9

2 Minimize conductive flow by well thermal insulation and fast thermal emission

Using thin structure, multilayer, having air layer, using strong radiation material, thermal insulation material to increase self-thermal resistance

4, 6,7, 8

3 Promote solar gain Use high-capacitance materials to store solar heat gain (night, cold season)

1, 2, 5, 9

4 Minimize solar gain using strong reflextion radiation material, creating shadown, shape and orient the building shell to minimize exposure to summer sun

4, 6, 7, 8

5 Promote natural ventilation Shape and orient the building shell to maximize exposure to summer breezes, use “open plan” to promote air flow in building interior and in the city

3*, 4 , 5*, 6*, 7, 8

6 Use mechanical cooling ventilation

Increasing wind velocity by low energy equipment (ceiling fan, wall fan)

4, 5, 6, 7, 8, 9*

7 Promote evaporative cooling Utilizing water heat evaporation for cooling surrounding air, increasing humidity

5, 7, 9

8 Reducing solar derect radiation penetrating through the window in the room

Design of shading devices, utilizing glass of reflected light, glass of heat absorption, glass of multilayer

4, 5, 6, 7, 8, 9

9 Taking advantage of surrounding environment temperature (earth, water, verdure)

Decreasing (summer) or increasing (winter) outdoor temperature by taking advantage of natural environment, verdure, water surface, protection and physical – chemical nature

1, 2, 3, 7, 8, 9

10 Use high-capacitance materials for controlled heat flow through the building envelope

Lag time design: lag time of building materials provide a design tool, allowing the thermal response of house wall and roofs to be selected according to their respective solar orientations

4, 5, 6, 7, 8, 9

11 Minimize infiltration Avoiding winter cold wind or lossing heat when warming or conditioning temperature

1, 2, 3, 8*, 9*

12 Opposing stagnant dew on floor, interiore surface in the room

Increasing inside surface temperature be higher than dew point temperature of indoor air flow

4, 6, 7, 8

13 Promote radiant cooling Utilizing surface which has low- temperature to decrease heat of human body, cooling

7, 8, 9

13

14 Hot radiation Warming the room by heat radiation (heater) 1, 2, 315 Artificial climatical conditioner Utilizing artificial device to reduce temperature and

humidity in the room8,9

(*) – strategy controlly applied It needs to pay attention that in a kind of climate can appear more or less bioclimatic zones of different frequency. Therefore a kind of climate can paralelly apply in the same time some design strategies, but there are strategies of first range, which are correlative with bioclimatic zone occuping the strongest position have to be included. We have introduced “matrix method selecting optimum strategy” for each locality.The order of carring out matrix method is as follows :(1) Combining table 1 and 2, establishing the table of possibility applying bioclimatic design strategies for locality reseaching. Example, table 3 established for Danang city

Table 3. Possibility applying bioclimatic design strategies for DanangHeat sensation zone % time appearing/year Climate-architecture strategies1- VC 0 -2- C 0 -3- SC 4,53 5*, 9, 12 4- CF 85,42 2, 4, 5, 6, 8, 10, 5- DC 0 -6- WC 8,85 2, 4, 5*, 6, 8, 10, 13*7- H 1,2 2, 4, 5, 6, 8, 9, 10, 13 8- VWH 0 -9- VDH 0 -

(2) Establishing matrix table: transverse direction putting 9 bioclimatic zones, vertical direction arranging 15 strategies in table 2 order. Exemple in table 4 for Danang city. (3) Giving mark for strategies being able to apply: Compartments in table 4 (where bioclimatic zone and applied strategy meet with) are mark number counted for each strategy being able to apply, correlative with frequency appeared in table 1.Giving mark method: - Each 1% frequency counted 1 mark - For strategy controlly applied, counted only 50% of mark number. - Compartments having no mark are strategy being not able apply. (4) Defining priority strategies by counting total mark for each strategy (total mark in transverse direction). Then arranging priority order in mark number, from high to low level.Exemple in table 4 is established for climate of Danang city.From table 4, it can define priority strategies in bioclimatic architecture design of Danang city as follows:- Priority No1: strategy 5 (natural ventilation)- Priority No2: strategies 2,4,8 and 10 (equal)Other strategies having considerably low mark number are not paid attention.The about mentioned matrix method of priority selection strategy has value specially when applied for countries having many kinds of considerable different bioclimatic zones.

Table 4. Defining priority architecture design strategies for Danang city

Strat.Giving marks for each strategy in bioclimatic zones Mark

additionCategory

VC C SC CF WC H VWH1 0 0 0 0 0 0 0 0 -2 0 0 0 85,42 8,85 1,2 0 95,47 23 0 0 0 0 0 0 0 0 -4 0 0 0 85,42 8,85 1,2 0 95,47 25 0 0 4,53 85,42 4,42 1,2 0 95,57 16 0 0 0 85,42 8,85 1,2 0 95,47 27 0 0 0 0 0 0 0 0 -

14

8 0 0 0 85,42 8,85 1,2 0 95,47 29 0 0 4,53 0 0 1,2 0 5,73 710 0 0 0 85,42 8,85 1,2 0 95,47 211 0 0 0 0 0 0 0 0 -12 0 0 4,53 0 0 0 0 4,53 913 0 0 0 0 4,42 1,2 0 5,62 814 0 0 0 0 0 0 0 0 -15 0 0 0 0 0 0 0 0 -

ConclusionThe man living with weather, but building staying in the climate. The weather is always change and directly impacts to the man. But the man is living body having ability of self-adjustment to adapt in the rather wide limitation of weather condition. Building cannot always change (or only change very few) to adapt every kind of weather, so it has to suit with a common law of climate at the locality that means adapting local climate. Bioclimatic approach method helps designer to define correct and adaptablest priority strategies with the climate. From then, designer with his experience and creative talent will propose concrete planning and architecture design solution which are the most suitable, ensuring works to harmonize with the nature, protect regional ecological environment.

15