DESI
GN
OF
NAT
URA
L VE
NTI
LATI
ON
WIT
H C
FD
Qin
gyan
Che
n
INTR
ODU
CTIO
N
As t
he p
revi
ous
chap
ter
dem
onst
rate
d, if
a b
uild
ing
ispr
oper
ly d
esig
ned,
nat
ural
ven
tilat
ion
can
prov
ide
both
a co
mfo
rtab
le a
nd h
ealth
y in
door
env
ironm
ent
as w
ell
as e
nerg
y sa
ving
s. M
ost
arch
itect
s an
d de
sign
ers
know
abou
t th
e pr
inci
ples
of
pass
ive
sola
r he
atin
g an
d ca
nin
dica
te h
ow t
hey
desi
re s
mal
l bu
ildin
gs t
o al
so t
ake
adva
ntag
e of
nat
ural
ven
tilat
ion,
as
show
n in
Fig
ure
1.N
atur
al v
entil
atio
n an
d th
erm
al c
omfo
rt, h
owev
er, a
redi
ffic
ult
to u
nder
stan
d an
d m
odel
, ev
en f
or s
impl
ebu
ildin
gs. It
is im
port
ant t
hat t
he a
rchi
tect
s and
eng
inee
rsco
llabo
rate
ear
ly in
the
desig
n pr
oces
s whe
n ke
y de
cisio
nsab
out m
aste
r pla
nnin
g an
d bu
ildin
g ge
omet
ry a
re m
ade.
The
pres
ent c
hapt
er il
lust
rate
s, us
ing
exam
ples
from
the
Sust
aina
ble
Urb
an H
ousi
ng i
n Ch
ina
case
stu
dies
,ho
w a
rchi
tect
s ca
n w
ork
with
eng
inee
rs t
o de
sign
asu
stai
nabl
e bu
ildin
g. W
ith th
e he
lp o
f the
com
puta
tiona
lflu
id d
ynam
ics
(CFD
) te
chni
que,
we
sugg
est
a de
sign
proc
edur
e as
follo
ws:
Firs
t, an
arc
hite
ct p
rodu
ces a
n in
itial
desi
gn. N
ext,
an e
ngin
eer
uses
the
CFD
tec
hniq
ue t
oca
lcul
ate
airf
low
s in
and
arou
nd th
e bu
ildin
gs. B
ased
on
the
calc
ulat
ed re
sults
, the
arc
hite
ct m
odifi
es th
e de
sign
.Se
vera
l it
erat
ions
are
oft
en n
eces
sary
to
achi
eve
satis
fact
ory
indo
or a
nd o
utdo
or e
nviro
nmen
t fo
r th
ebu
ildin
g. S
ince
an
arch
itect
gen
eral
ly d
oes
not
have
suff
icie
nt kn
owle
dge
of fl
uid
dyna
mic
s or n
umer
ical
skill
s,th
e en
gine
er p
lays
an
esse
ntia
l ro
le i
n he
lpin
g th
e
CHAP
TER
SEVE
N
L. G
licks
man
and
J. L
in (e
ds),
Sust
aina
ble
Urb
an H
ousin
g in
Chi
na, 1
16-1
23©
2006
Spr
inge
r. Pr
inte
d in
the
Net
herla
nds.
117
Chap
ter S
even
- D
esig
n of
Nat
ural
Ven
tilat
ion
with
CFD
arch
itec
t ob
tain
the
det
aile
d fl
ow i
nfor
mat
ion.
The
engi
neer
, in
turn
, rel
ies
on t
he a
rchi
tect
to
mak
e th
ebu
ildin
g co
mfo
rtab
le a
nd h
ealth
y.Th
is c
hapt
er i
llust
rate
s th
is p
roce
ss t
hrou
gh t
hede
sign
of a
smal
l, na
tura
lly v
entil
ated
bui
ldin
g in
Bei
jing
(Bei
jing
City
Gar
den)
and
the
ana
lysi
s of
a b
uild
ing
site
in B
eijin
g fo
r ou
tdoo
r th
erm
al c
omfo
rt a
nd n
atur
alve
ntila
tion
(Bei
jing
Star
Gar
den)
.
Nat
ural
Ven
tilat
ion
Desi
gnFi
gure
2 s
how
s th
e lo
catio
n of
the
six-
stor
y (2
0 m
eter
s)de
mon
stra
tion
build
ing
and
its s
urro
undi
ngs
in B
eijin
gCi
ty G
arde
n, B
eijin
g. T
here
is a
long
, mid
-ris
e bu
ildin
g,40
met
ers
high
, to
the
nor
th a
nd l
ow-r
ise
six-
stor
ybu
ildin
gs to
the
east
and
sout
h. A
wid
e st
reet
runs
alo
ngth
e w
est
of t
he d
emon
stra
tion
build
ing.
Our
des
ign
inth
is c
ase
focu
sed
on n
atur
al v
entil
atio
n.Th
e de
sign
of n
atur
al v
entil
atio
n in
the
dem
onst
ratio
nbu
ildin
g re
quire
d da
ta o
n in
door
and
out
door
airf
low
dist
ribut
ions
. The
win
d ro
se in
Bei
jing,
as s
how
n in
Figu
re3,
indi
cate
d th
at in
the
sum
mer
the
pre
vaili
ng w
ind
isfr
om n
orth
and
sou
th. T
he c
orre
spon
ding
mea
n w
ind
spee
d is
1.9
m/s
. Fig
ure
4 br
eaks
the
ref
eren
ce w
eath
erda
ta i
n Be
ijing
int
o di
ffer
ent
com
fort
cat
egor
ies.
Alth
ough
hea
ting
is
an i
mpo
rtan
t is
sue
in B
eijin
g,bu
ildin
gs t
here
als
o re
quire
coo
ling
from
Jun
e th
roug
hAu
gust
. How
ever
, the
fig
ure
illus
trat
es t
hat
the
perio
dof
com
fort
can
be
incr
ease
d su
bsta
ntia
lly, a
nd th
e le
vel
of m
echa
nica
l coo
ling
redu
ced,
if m
ean
air s
peed
in th
ebu
ildin
g is
at l
east
2 m
/s th
roug
h na
tura
l ven
tilat
ion
orin
tern
al o
verh
ead
fans
. Ind
eed,
air-
cond
ition
ing
may
not
be n
eces
sary
in B
eijin
g if
natu
ral v
entil
atio
n is
com
bine
dw
ith
nigh
t co
olin
g. E
xces
s w
ind
spee
d, h
owev
er,
isde
trim
enta
l, cau
sing
disc
omfo
rt to
ped
estr
ians
. In
Beiji
ng,
win
ter
win
ds a
roun
d so
me
build
ings
can
rea
ch s
peed
sof
14
m/s
. Con
side
ring
the
low
air
tem
pera
ture
in t
he
Figu
re 1
Sm
art a
rrow
s us
ed b
y ar
chite
cts
(Sou
rce:
ada
pted
from
Moo
re 1
993)
Figu
re 2
The
dem
onst
ratio
n bu
ildin
g (s
hade
d) a
nd it
s si
te(B
eijin
g Ci
ty G
arde
n)
Figu
re 3
Win
d ro
se fo
r Bei
jing.
Thi
ck s
olid
line
: who
le y
ear;
thin
sol
id li
ne: w
inte
r (D
ecem
ber,
Janu
ary,
and
Feb
ruar
y);
dash
ed li
ne: s
umm
er (J
une,
Jul
y, a
nd A
ugus
t).
Figu
re 4
Com
fort
zon
es fo
r dev
elop
ing
coun
trie
s (S
ourc
e: C
arril
ho d
a G
raça
et a
l 200
2)
Hours per Month (Year)
118
Part
Thr
ee -
Tec
hnic
al F
indi
ngs
win
ter,
the
chi
lling
eff
ect
of t
his
win
d pr
even
tspe
dest
rians
from
wal
king
com
fort
ably
and
saf
ely.
Usi
ng th
e w
ind
info
rmat
ion
and
build
ing
site
, a C
FDpr
ogra
m
calc
ulat
ed
the
airf
low
ar
ound
th
ede
mon
stra
tion
build
ing,
as s
how
n in
Figu
re 5
. Whe
n w
ind
was
fro
m t
he n
orth
, the
air
spee
d ar
ound
the
bui
ldin
gw
as a
bout
0.1
m/s
~ 0
.4 m
/s, w
hich
is to
o lo
w to
supp
ort
natu
ral v
entil
atio
n of
uni
ts. T
his r
educ
tion
in a
ir ve
loci
tyoc
curs
bec
ause
the
build
ing
site
is in
a re
circ
ulat
ion
zone
,cr
eate
d by
the
tall
build
ing
to th
e no
rth.
Whe
n th
e w
ind
was
fro
m t
he s
outh
, th
e ai
r sp
eed
arou
nd t
hede
mon
stra
tion
build
ing
was
hig
her b
ut st
ill lo
w, b
etw
een
0.3
and
0.8
m/s
. Th
e sm
all
dist
ance
bet
wee
n th
ede
mon
stra
tion
build
ing
site
and
adj
acen
t bu
ildin
gs t
oth
e so
uth
defle
cts
win
d be
fore
it re
ache
s th
e bu
ildin
g.D
espi
te t
hese
con
ditio
ns, t
he d
esig
n te
am c
hose
to
use
the
avai
labl
e, a
lbei
t lo
w-v
eloc
ity, w
ind
to p
rovi
dena
tura
l ven
tilat
ion
to t
he b
uild
ing.
Sin
ce t
he d
esig
n of
natu
ral
vent
ilatio
n do
es n
ot u
sual
ly i
ncre
ase
build
ing
cons
truc
tion
and
oper
atio
n co
sts,
it is
alw
ays w
orth
whi
leto
try
to
inco
rpor
ate
such
sys
tem
s, w
hen
basi
c cl
imat
icco
nditi
ons
will
per
mit
ther
mal
ly c
omfo
rtab
le t
hrou
gh-
vent
ilatio
n. F
igur
e 6
show
s tw
o de
sign
sch
emes
for
aty
pica
l fl
oor
of t
he d
emon
stra
tion
bui
ldin
g, b
oth
desi
gned
to
allo
w f
ree
pass
age
of w
ind.
Thi
s ch
apte
rde
mon
stra
tes
how
the
CFD
tec
hniq
ue i
s us
ed t
ode
term
ine
the
nece
ssar
y si
ze o
f the
cou
rt t
o th
e so
uth.
The
proj
ect
team
exp
ects
tha
t th
e co
urt
will
inc
reas
ena
tura
l lig
ht in
the
build
ing,
cre
ate
a so
cial
spac
e fo
r the
build
ing
resi
dent
s, an
d ch
anne
l win
d fr
om th
e so
uth
for
vent
ilatio
n.Fi
gure
7 sh
ows t
he a
irflo
w d
istrib
utio
n in
and
aro
und
the
dem
onst
ratio
n bu
ildin
g w
hen
the
win
d co
mes
from
the
sout
h. Th
e se
para
tion
of d
etai
led
airf
low
info
rmat
ion
with
in t
he d
emon
stra
tion
build
ing
from
the
airf
low
arou
nd B
eijin
g Ci
ty G
arde
n (F
igur
e 5b
) re
duce
dco
mpu
ting
time
sign
ifica
ntly
. Bec
ause
win
d sp
eed
from
the
sout
h ar
ound
the
dem
onst
rati
on b
uild
ing
is0.
3 ~
0.8
m/s
, CFD
mod
els o
f airf
low
with
in th
e bu
ildin
gas
sum
ed w
ind
from
the
sou
th a
t a
unifo
rm s
peed
of
0.5
m/s
. The
mod
el sh
ows t
hat t
he b
uild
ing
layo
ut p
erm
itsfr
ee, e
asy
vent
ilatio
n of
the
uni
ts. H
owev
er, c
ourt
siz
eha
s no
signi
fican
t im
pact
on
the
airf
low
pat
tern
and
flow
rate
. Fur
ther
mor
e, t
he r
esul
ts s
ugge
st t
hat
mec
hani
cal
vent
ilatio
n or
stac
k ve
ntila
tion
mig
ht b
e ne
eded
in o
rder
to e
nhan
ce t
he v
entil
atio
n in
the
bui
ldin
g. C
hapt
er 5
docu
men
ts th
e im
pact
on
ther
mal
com
fort
of s
peci
fied
air c
hang
e ra
tes a
ssist
ed b
y m
echa
nica
l ven
tilat
ion.
With
an o
pen
inte
rior d
esig
n fo
r nat
ural
ven
tilat
ion,
fan
pow
erfo
r ade
quat
e st
ack
vent
ilatio
n w
ill b
e ke
pt to
a m
inim
um.
Thes
e re
sult
s w
ere
impo
rtan
t in
ref
inin
g th
e fi
nal
vent
ilatio
n de
sign
. See
Cha
pter
10,
Cas
e St
udy
One
–Be
ijing
Pro
toty
pe H
ousi
ng fo
r mor
e in
form
atio
n.
Out
door
Com
fort
and
Site
Pla
nnin
gA
seco
nd e
xam
ple
dem
onst
rate
s ho
w a
rchi
tect
s an
den
gine
ers
can
wor
k to
geth
er t
o de
sign
a c
omfo
rtab
leou
tdoo
r and
indo
or e
nviro
nmen
t. Ac
cele
ratio
n of
airf
low
amon
g hi
gh-r
ise
build
ings
may
cre
ate
outd
oor c
omfo
rtpr
oble
ms.
This
stud
y us
es th
e Be
ijing
Sta
r Gar
den
Proj
ect
as a
n ex
ampl
e of
how
to d
esig
n a
com
fort
able
out
door
envi
ronm
ent.
Beca
use
it is
mai
nly
the
chill
ing
effe
ct o
f the
win
d in
the
win
ter t
hat c
ause
s the
out
door
dis
com
fort
pro
blem
,th
e de
sign
ana
lyze
d th
e ai
rflo
w d
istr
ibut
ion
on a
win
ter
day.
The
win
d ro
se f
or B
eijin
g (F
igur
e 3)
illu
stra
tes
that
in t
he w
inte
r th
e pr
evai
ling
win
d is
fro
m t
he n
orth
(5° i
nclin
ed to
the
wes
t). I
n a
typi
cal y
ear,
ther
e ar
e ni
neda
ys d
urin
g w
hich
the
win
d sp
eed
is h
ighe
r th
an7.
6 m
/s in
Bei
jing
(ASH
RAE
1997
), an
d hi
gh w
ind
days
gene
rally
occ
ur in
the
win
ter.
The
pres
ent i
nves
tigat
ion
stud
ied
a sc
enar
io w
ith a
nor
th w
ind
of 7
.6 m
/s f
orou
tdoo
r the
rmal
com
fort
con
side
ratio
n.
119
Chap
ter S
even
- D
esig
n of
Nat
ural
Ven
tilat
ion
with
CFD
Figu
re 5
aTh
e ai
rflo
w d
istr
ibut
ion
arou
nd th
e de
mon
stra
tion
build
ing
sect
ion
with
ano
rth
win
d; e
xist
ing
tall
build
ings
sho
wn
on th
e le
ft-h
and
side
of t
he fi
gure
Figu
re 5
bTh
e ai
rflo
w d
istr
ibut
ion
arou
nd th
e de
mon
stra
tion
build
ing
sect
ion
with
aso
uth
win
d; e
xist
ing
tall
build
ings
are
sho
wn
on th
e le
ft-h
and
side
of t
he fi
gure
Figu
re 6
A ty
pica
l flo
or p
lan
of th
e de
mon
stra
tion
build
ing
with
diff
eren
t cou
rt s
izes
Figu
re 7
The
air
velo
city
in a
nd a
roun
d th
e de
mon
stra
tion
build
ing
at a
hei
ght o
f 1.2
met
ers
abov
e th
e flo
or: (
a) s
how
s ai
r vel
ocity
in th
e pl
an w
ith th
e la
rge
cour
t, an
d (b
) sho
ws
a si
mila
rpl
an w
ith a
sm
alle
r cou
rt
(a)
(b)
dem
onst
ratio
nbu
ildin
g
dem
onst
ratio
nbu
ildin
g
120
Part
Thr
ee -
Tec
hnic
al F
indi
ngs
Figu
re 8
a O
rigin
al d
esig
n fo
r Bei
jing
Star
Gar
den
by a
nar
chite
ctur
al fi
rm (s
chem
e I)
Figu
re 8
b P
relim
inar
y re
desi
gn fo
r Bei
jing
Star
Gar
den
by M
ITpr
ojec
t tea
m (s
chem
e II)
Figu
re 8
c S
econ
d re
desi
gn fo
r Bei
jing
Star
Gar
den
by M
IT p
roje
ctte
am (s
chem
e III
)
Figu
re 9
Win
d ve
loci
ty d
istr
ibut
ion
at th
e he
ight
of 1
.5 m
abo
veth
e gr
ound
aro
und
the
build
ings
for s
chem
e I w
ith a
nor
th w
ind
(blu
e -
low
vel
ocity
, gre
en -
mod
erat
e ve
loci
ty, a
nd y
ello
w/r
ed -
high
vel
ocity
)
Figu
re 1
0 W
ind
velo
city
dis
trib
utio
n at
the
heig
ht o
f 1.5
mab
ove
the
grou
nd a
roun
d th
e bu
ildin
gs fo
r sch
eme
II w
ith a
nor
thw
ind
(blu
e -
low
vel
ocity
, gre
en -
mod
erat
e ve
loci
ty, a
nd y
ello
w/
red
- hi
gh v
eloc
ity)
Figu
re 1
1 W
ind
velo
city
dis
trib
utio
n at
the
heig
ht o
f 1.5
mab
ove
the
grou
nd a
roun
d th
e bu
ildin
gs fo
r sch
eme
III w
ith a
nort
h w
ind
(7.6
m/s
) (b
lue
- lo
w v
eloc
ity, g
reen
- m
oder
ate
velo
city
, and
yel
low
/red
- h
igh
velo
city
)
Figu
re 1
2 W
ind
velo
city
dis
trib
utio
n at
the
heig
ht o
f 1.5
mab
ove
the
grou
nd a
roun
d th
e bu
ildin
gs fo
r sch
eme
III w
ith a
sout
h w
ind
(1.9
m/s
) (b
lue
- lo
w v
eloc
ity, g
reen
- m
oder
ate
velo
city
, and
yel
low
/red
- h
igh
velo
city
)
A B C
1 1
AB
121
Chap
ter S
even
- D
esig
n of
Nat
ural
Ven
tilat
ion
with
CFD
Figu
re 8
a sh
ows
the
deve
lope
r’s o
rigin
al s
ite d
esig
n(s
chem
e I).
The
des
ign
for s
chem
e I c
onsi
sted
of s
ixte
enhi
gh-r
ise
build
ings
ran
ging
fro
m 3
3 to
90
met
ers
high
.Th
is c
hapt
er p
rese
nts t
he w
ind
spee
d di
strib
utio
n at
the
heig
ht o
f 1.
5 m
eter
s ab
ove
the
grou
nd t
o ev
alua
tepe
dest
rian
com
fort
(Fig
ure
9). T
he w
ind
spee
d at
sect
ion
1-1
is a
roun
d 8~
9 m
/s (g
rade
5),
too
high
to b
e ac
cept
edev
en fo
r a sh
ort s
tay
in th
e w
inte
r. Th
e lin
ear a
rran
gem
ent
of t
he b
uild
ings
per
mits
win
d to
pas
s fr
eely
. The
CFD
calc
ulat
ion
also
show
s tha
t at a
hei
ght o
f 30
met
ers,
the
win
d sp
eed
amon
g m
ost
of t
he b
uild
ings
is 9
~10
m/s
,an
d at
a h
eigh
t of
70
met
ers,
the
win
d sp
eed
is a
bove
12 m
/s (g
rade
6).
The
high
win
d sp
eed
lead
s to
exce
ssiv
ein
filtr
atio
n in
the
win
ter a
nd d
iffic
ultie
s in
usin
g th
e w
ind
for n
atur
al v
entil
atio
n in
the
sum
mer
. The
refo
re, t
he M
ITte
am m
ade
reco
mm
enda
tions
to th
e de
velo
per t
hat t
hebu
ildin
g si
te s
houl
d be
red
esig
ned,
and
the
hei
ght
ofth
e bu
ildin
gs s
houl
d be
redu
ced.
Sinc
e th
e CF
D c
alcu
latio
ns s
how
ed t
hat
the
heig
htof
bui
ldin
gs i
n de
sign
I c
ause
s a
serio
us d
isco
mfo
rtpr
oble
m, t
he M
IT d
esig
n te
am p
rodu
ced
sche
mes
II a
ndIII
(Fig
ures
8b
and
8c) w
ith th
e fo
llow
ing
feat
ures
:
•lo
wer
ove
rall
build
ing
heig
ht (b
uild
ing
heig
hts r
ange
from
20
to 6
0 m
eter
s in
sche
me
II, a
nd fr
om 2
0 to
50
met
ers i
n sc
hem
e III
) to
redu
ce w
inte
r inf
iltra
tion
and
to p
rovi
de o
ppor
tuni
ty f
or s
umm
er n
atur
alve
ntila
tion,
with
out
com
prom
isin
g th
e po
pula
tion
dens
ity; a
nd•
prot
ectio
n fr
om th
e no
rth
win
d in
the
win
ter b
y us
ing
rela
tivel
y hi
gh b
uild
ings
in th
e no
rth.
Figu
re 1
0 sh
ows
that
sch
eme
II r
educ
es t
hedi
scom
fort
pro
blem
gre
atly
, but
pro
blem
s rem
aine
d. F
orex
ampl
e, in
ent
ranc
es A
, B, a
nd C
, the
win
d sp
eed
was
very
hig
h be
caus
e of
the
linea
r arr
ange
men
t. St
agge
ring
the
entr
ance
s cou
ld e
asily
solv
e th
is p
robl
em. A
num
ber
of o
ther
iss
ues
need
ed t
o be
car
eful
ly e
xam
ined
. For
inst
ance
, nat
ural
ven
tilat
ion
in th
e su
mm
er m
ay n
ot b
eef
fect
ive
in sc
hem
e II.
As s
how
n in
Fig
ure
8b, m
ore
than
half
of th
e bu
ildin
gs h
ave
a lo
ng si
de fa
cing
eas
t or w
est.
Sinc
e th
e pr
evai
ling
win
d in
the
sum
mer
is fr
om th
e so
uth
in t
his
site
, the
bui
ldin
gs w
ith t
he lo
ng s
ide
faci
ng e
ast
or w
est
may
not
tak
e ad
vant
age
of n
atur
al c
ross
vent
ilatio
n. I
n ad
ditio
n, t
he o
rient
atio
n w
as n
ot g
ood
for p
assi
ve h
eatin
g de
sign
, and
it w
as d
iffic
ult t
o sh
ade
the
build
ing
from
the
str
ong
sola
r ra
diat
ion
in t
hesu
mm
er.
Base
d on
the
res
ults
for
sch
eme
II, t
he M
IT t
eam
desi
gned
sch
eme
III. T
he l
ow-r
ise
build
ings
wer
e no
wti
lted
45°
, w
ith
the
long
sid
e fa
cing
sou
thea
st a
ndno
rthw
est.
In sc
hem
e III
, bot
h ou
tdoo
r the
rmal
com
fort
and
natu
ral v
entil
atio
n w
ere
cons
ider
ed. W
hen
stud
ying
the
outd
oor
ther
mal
com
fort
, the
inco
min
g w
ind
was
set
to b
e 7.
6 m
/s f
rom
the
nor
th. F
igur
e 11
sho
ws
the
win
d di
strib
utio
n fo
r sch
eme
III fo
r eva
luat
ing
pede
stria
nco
mfo
rt. T
he h
igh-
rise
build
ings
on
the
nort
h si
de c
anbl
ock
the
high
win
d fr
om th
e no
rth.
As a
resu
lt, th
e w
ind
spee
d in
the
site
is lo
w. W
hile
win
d sp
eeds
at
poin
ts A
and
B w
ere
high
, the
se a
re v
ehic
ular
ent
ranc
es th
at w
illno
t aff
ect p
edes
tria
n co
mfo
rt.
Sinc
e th
e hi
gh-r
ise
build
ings
wer
e us
ed to
blo
ck th
ew
ind
in th
e w
inte
r, it
is ha
rd to
use
nor
th w
ind
for n
atur
alve
ntila
tion
in
the
sum
mer
. In
Bei
jing,
pro
tect
ing
pede
stri
ans
from
the
col
d w
inte
r w
ind
was
mor
eim
port
ant
than
uti
lizin
g na
tura
l ve
ntila
tion
in
the
sum
mer
. How
ever
, it w
as fe
asib
le to
use
sou
th w
ind
for
natu
ral v
entil
atio
n. Th
e m
ean
win
d sp
eed
in th
e su
mm
erfr
om th
e so
uth
is 1.
9 m
/s. W
ith su
ch a
win
d sp
eed,
Figu
re12
sho
ws
that
the
win
d sp
eed
arou
nd m
ost
of t
hebu
ildin
gs a
t 1.
5 m
eter
s ab
ove
the
grou
nd i
s ab
ove
1.0
m/s
. Thi
s w
ind
spee
d is
suf
ficie
ntly
hig
h fo
r na
tura
lve
ntila
tion.
The
tilt
ed b
uild
ing
arra
ngem
ent
help
ed t
oin
trod
uce
mor
e w
ind
into
the
site
. Fur
ther
mor
e, t
he
122
Part
Thr
ee -
Tec
hnic
al F
indi
ngs
stag
gere
d ar
rang
emen
t pr
even
ted
the
fron
t bu
ildin
gsfr
om b
lock
ing
win
ds. T
here
fore
, sch
eme
III p
rovi
ded
good
outd
oor
ther
mal
com
fort
and
pot
entia
l to
use
natu
ral
vent
ilatio
n. N
ote
that
sche
me
III w
as n
ot th
e fin
al d
esig
n.In
add
itio
n to
the
ven
tila
tion
stu
dies
sho
wn
in t
his
chap
ter,
the
desig
n te
am st
udie
d ot
her i
mpo
rtan
t iss
ues,
such
as
sun
avai
labi
lity,
nat
ural
ligh
ting,
and
ene
rgy
inbu
ildin
gs. S
ee C
hapt
er 1
1, C
ase
Stud
y Tw
o –
Beiji
ng S
tar
Gar
den
for m
ore
info
rmat
ion.
SUM
MAR
Y
This
cha
pter
sho
ws
how
eng
inee
rs c
an u
se C
FD t
o he
lpar
chite
cts
desi
gn n
atur
al v
entil
atio
n in
bui
ldin
gs a
ndzo
nes o
f the
rmal
com
fort
aro
und
build
ings
. With
the
help
of th
e CF
D te
chni
que,
eng
inee
rs c
an c
alcu
late
the
airf
low
dist
ribut
ions
in a
nd a
roun
d bu
ildin
gs, a
nd a
rchi
tect
s can
use
the
resu
lting
info
rmat
ion
to m
odify
thei
r des
igns
.Th
e CF
D t
echn
ique
allo
ws
engi
neer
s to
qui
ckly
and
inex
pens
ivel
y an
alyz
e ai
rflo
w in
and
aro
und
build
ings
.Th
e in
form
atio
n ca
n he
lp a
rchi
tect
s to
des
ign
build
ings
that
can
be
mor
e ef
fect
ivel
y ve
ntila
ted
in s
umm
er a
ndth
at c
an a
void
stro
ng o
utdo
or w
ind
in w
inte
r to
achi
eve
bett
er t
herm
al c
omfo
rt.
This
cha
pter
des
crib
es t
wo
exam
ples
of
build
ing
desi
gn w
ith C
FD, o
ne f
or n
atur
alve
ntila
tion
and
anot
her
for
outd
oor
ther
mal
com
fort
.Th
e st
ep-b
y-st
ep d
esig
n pr
oced
ure
show
s the
use
fuln
ess
of C
FD a
nd h
ow e
ngin
eers
and
arc
hite
cts
can
wor
kto
geth
er to
ach
ieve
bet
ter b
uild
ing
desi
gn.
In th
e na
tura
l ven
tilat
ion
desi
gn, t
he re
sults
show
edth
at t
he w
ind
dire
ctio
n an
d bu
ildin
g si
te i
nfor
mat
ion
wer
e m
ost c
ruci
al fo
r the
ven
tilat
ion
rate
, whi
le th
e co
urt
size
was
not
as i
mpo
rtan
t. In
the
case
of o
utdo
or th
erm
alco
mfo
rt d
esig
n an
d si
te p
lann
ing,
the
res
ults
indi
cate
that
one
can
impr
ove
the
desi
gn b
y bu
ildin
g sh
ape
and
orie
ntat
ion.
How
ever
, ot
her
fact
ors,
suc
h as
sol
ar
avai
labi
lity,
sho
uld
also
be
cons
ider
ed t
o ob
tain
asu
stai
nabl
e de
sign
.Se
vera
l it
erat
ions
may
be
nece
ssar
y to
des
ign
abu
ildin
g w
ith s
atis
fact
ory
indo
or a
nd o
utdo
or c
omfo
rten
viro
nmen
t. Th
is d
esig
n pr
oced
ure,
und
erta
ken
by a
team
of a
rchi
tect
s and
eng
inee
rs a
t MIT
, sho
ws t
hat t
heCF
D t
echn
ique
is a
ver
y us
eful
too
l for
bui
ldin
g de
sign
.Th
is k
ind
of c
oope
rati
on b
etw
een
arch
itec
ts a
nden
gine
ers
is n
eces
sary
to d
esig
n go
od b
uild
ings
.Al
thou
gh t
he C
FD t
echn
ique
has
gre
at p
oten
tial f
orbu
ildin
g de
sign
, it
is t
ime
cons
umin
g. T
o m
itiga
te t
his,
the
arch
itect
s an
d en
gine
ers
on a
pro
ject
sho
uld
revi
ewin
itial
des
igns
bas
ed o
n th
eir e
xper
ienc
e an
d kn
owle
dge.
This
dis
cuss
ion
will
red
uce
the
requ
ired
num
ber
ofite
ratio
ns s
igni
fican
tly a
nd c
an s
peed
up
the
desi
gnpr
oces
s. Th
e CF
D t
echn
ique
sho
uld
be u
sed
only
to
eval
uate
a fe
w, f
inal
des
ign
alte
rnat
ives
bec
ause
of t
hedi
ffic
ulty
of p
erfo
rmin
g th
e an
alys
is.
REFE
REN
CES
ASH
RAE.
199
7. H
andb
ook
of F
unda
men
tals
. Am
eric
anSo
ciet
y of
Hea
ting
, R
efri
gera
ting
, an
d A
ir-
Cond
ition
ing
Engi
neer
s, At
lant
a, G
A.Ca
rrilh
o da
Gra
ça, G
., Q. C
hen,
L. G
licks
man
and
L. N
orfo
rd.
2002
. Sim
ulat
ion
of W
ind-
Driv
en V
entil
ativ
e Co
olin
gSy
stem
s fo
r an
Apa
rtm
ent
Build
ing
in B
eijin
g an
dSh
angh
ai.E
nerg
y an
d Bu
ildin
gs, 3
4(1)
: 1-1
1.Ch
en, D
. and
J. C
ai. 1
994.
Doc
umen
ts C
olle
ctio
n fo
rBu
ildin
g D
esig
n, v
ol.
1(i
n C
hine
se).
Chi
nese
Cons
truc
tion
Indu
stry
Pub
licat
ion
Inc.
, Bei
jing.
Chen
, Q. 1
997.
Com
puta
tiona
l Flu
id D
ynam
ics f
or H
VAC:
Succ
esse
s and
Fai
lure
s. Am
eric
an S
ocie
ty o
f Hea
ting,
Ref
rige
rati
ng a
nd A
ir-C
ondi
tion
ing
Engi
neer
sTr
ansa
ctio
ns, 1
03 (1
): 17
8-18
7.
123
Chap
ter S
even
- D
esig
n of
Nat
ural
Ven
tilat
ion
with
CFD
Giv
oni,
B. 1
997
Clim
ate
Cons
ider
atio
ns in
Bui
ldin
g an
dU
rban
Des
ign.
Van
Nos
tran
d Re
inho
ld ,
New
Yor
k.M
oore
, F. 1
993
Envi
ronm
ent
Cont
rol S
yste
ms:
Hea
ting
Cool
ing
Ligh
ting.
McG
raw
-Hill
, Inc
., N
ew Y
ork.
Mur
akam
i, S.
199
8. O
verv
iew
of
Turb
ulen
ce M
odel
sAp
plie
d in
CW
E-19
97. J
ourn
al o
f W
ind
Engi
neer
ing
and
Indu
stria
l Aer
odyn
amic
s, 74
-76:
1-2
4.Vi
cker
y, B
. and
C. K
arak
atsa
nis.
1987
. Ext
erna
l Pre
ssur
eD
istr
ibut
ions
and
Indu
ced
Inte
rnal
Ven
tilat
ion
Flow
in L
ow-R
ise
Indu
stri
al a
nd D
omes
tic
Stru
ctur
es,
Amer
ican
Soc
iety
of H
eatin
g, R
efrig
erat
ing,
and
Air-
Cond
itio
ning
Eng
inee
rs T
rans
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ons,
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3.
