Download - Cap 2 the Solar Resource
-
8/17/2019 Cap 2 the Solar Resource
1/7
The
solar
resource
11,1)ll nn
Sf
,itln
Thc
Sun
is tl-rc'
cerrtlal
energl' producel of our solal
s-vstcm.
lt is
l
1,390.000 km
diamctcr- sphere
rvith
nuclel
fusion
taking
place
contiruously
in
its
centr-e.
A
snrall
fl'actior.r
of tlrc
encrgl' produced in the Sun hits the Earth
ancl urakes
life
posible
on our
pllrct.
Solal
radiation dlives
lll
narulaL c,vcles and processes sucli as raili,
g,ind,
photosynthesis, ocean
currents
and
sever: othe$ rvlich lr-e inlpoltait for
lifc. The rvorlcl's enelgl' need
has
been
based
fionr dre ver')'
beqinning on
solar
ener-gy. All
lossil iuels
(oil,
gas, coal) ar',: converted
solar enerst'.
The
solar radiation
is cmittcd
b,v
the
Sunls col-ona
at ur
ellLctive blackbocl,v
tcrrlpcr-atrlr-c ofapproxirratell.5ll(X)
K..virh
an
irradiance
(tt'r-nrs
ar-e delired
in
tlre
Appcndix) of 70,(X)0 8(l,0il0 kW/nrr.
Or-rr-planet
receives
only a
ver,v
smdl
por-tion
ofthis
er-rergy
Il
spite
ofdris, thc incoruing
soJar-radiation
energt'in
a
1c-rl
rs
sonre
1
5r
10r"
kWh: this
is
abour
15,000 timcs
thc
1-carly
cncrgJ.
nccd
of tl.rc rvholc
rvorld rn
2000
(10
r
kWh/a;
BPAnroco, 2002).
The
dur-atiou
ofthc sunshinc:s s.ell as
the solar
ilradi:rnce
is
cleperldent
on
the
tir11e
of
the
,vear,
wcithcr
.onditions and nattudly
also
on
thc
gcogirphical
location.
Thc
amourt ofycady
global
mdietion
(on
l
horizonul
surfaccJ
rn
the sunbclr
rcgronr rnrl-
cxceccl
2200
kWl-r/lnr.
In
trortheln
Eu]opc-,
the
rnarinrunr value
is
rbout
1100
kWh/mr.
2.1 SOLAR RADIATION
AND AMBIENT
TEMPERATURE
Thc'
climate
is
one
of
the
key
lactors influc'ricing the erlerll)-
yield
of
:r
solar
conrbisystenr.
This inter-action t:rkes pl:1cc on scvcral lcvcls:
.
Sol:rr collector:
The
absolbcl
tcmpclatllrc is
dcpendcnt
on
the
solar Lldietion
on
thc solar
collector.
Losscs
to
tl-re ambient
are
driven b,v the
tempc'1atulc
difli:rclcc bc' vcen the
,t,llccror
rbrorb.t'
.rnd
rlr.
.rrttbicrtr.
.
Heat
demand ofthe
building:
-
Heat
losses
to the :rnrbient
are
driven by the telrlpelatrile dilltrcncc
bcnvcc,n
the
house
and the ambielit
(air:rnd
ground).
-
Solar
ladiltion
th-ough
the
rvindorvs
can be seen as
inner-heat gains
in
thc
pcriod
ofthe
year.rvhen
sp:rce
hearing
is
effectively needed
(heating
scason).
.
Domcsric hot
rv:rtcr
(DHW)
demalid
-
The
cold
water-
terlperatule
fiom
the
ntrins
varies
over thc
ycar.This
variation
is
ruainly
dependerrr
on
the aver-agc- rlolrthly :11-ub1e11t telllpeliltures.
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THE SOLAR RESOURCE
11
Clinrate
varies
fiom
location to locatiorr
and
fiorn
year
to
year.
Figures
2.1 arLd
2.2
shorv
dre
rvodd's
yeally average
global irradiation
arid the Earth'.s surface
tenlperature.
In
Figure
2.3
thc
average
values
of
solar
irradiation
arrd outdoor
lemperatura:
y6ar
loCl
Figure
2.2.
Warld
map al
),early
avelage
amblent
temperaturc in
"C.
(Saurce.
METEOTESI
Bene,
Switzerland, http.
//wwwmeteanom.com).
See also calaur
plate
2
l3
6..0.
soo
:
ao.
loao
:
1050.. 1200
.
;
?1oo
.
23@
B&
>
?3oo
Glob6l lrradiation:
yoar
lkWhi
m7l
Fryure
2.7
.
Wold
map
of
yearly
average
global
irradlatian
(an
a horizantal surface) in
kwh/mta
lsource
METEOTESI Bernc, Swiae and, http
//www.meteanarm.cam).
See alsa calaut
plate
1
T
r
F
o
CO
il <
'r'
,l
in
''l
r-lI
nl,|LJ
)-,1
lo
.T
=
z
*
..ro
i:,
-2o..
ro
I
-ro.
"s
5.
O
. lo.
16
L:15.ro
[:
?0.
2.
I
ts
-
rr.s
&
>
17.6
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12
SOIAR
HEAT
NG
SYSTEIVS
FOR
HOUSES:
A DESIGN
HANDBOOK
tOR
SOLAR
COMBISYSTEMS
Monthly
values
of ambient
temperature'199'l
_
2000
-1991
1992
-
1993
1994
-
1995
-
1996
1997
*
't
998
'1999
2000
*Average
Monthly
values
ot
globalirradiation
1991
-
2000
,ru.trsf
,f+d
p*
9r$ro odsdo-i
0-
su .e
sf
"f
"d
s
,v
"9
,o
od
r.d
o(9
Fiqure
2.3.
fen
tear
manthtv
average
ambient
temperature
and
(harizantal) glabal
iradiation
far
.;-ontr"l
LLtaaearto.
dttan
/4\,4G.
./041)
temperAture
for
one
locirtlon
over
10 ye;rrs
are shorvD'
Despite
the
obvious
seasonal
t..rri,
"
wid.
range of
flucluations
be
veen
the
nlonths
can be
seen
ln
ordel
to
compare
the
p"r:forrrr"rtaa
of
different
con'tbisystems
under
ditTelcnt
climate
ao,rii,io,r,
on
tira
,"rrr"
basis,
average
data
for
each
location
alc
necded'
The orientation
ofthe
absorbers
(rvindorv,
collector)
is
also
signifrcant
Figrre
2'tr
shows
the
monthly
hemispherical
irradiation
on
difiercntly
orienteted
surfaces
fol
x
centnl
E.,rop."n
climate
lt
can
be
seen
that horizont:rl
surdtces
end surfaces
lrcing
south
rvirh
I
tilt
angle of'tSo
have
much
higher
sumluer
than r'r'inter
lTl
1S93
Ln.o
I
-
1995
1997
-
1998
I
1999
2ooo
5.0
0.0
-5.0
'150
E
=
loo
sofr
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4/7
THE
SOLAR RESOURCE
13
t
2oo
E^
:
150
=
3
roo
.g
.>50
z
E
0
JAN
FEB
I]/IAR
APR
MAY
JUN JUL
AUG SEP OCT NOV DEC
Figurc
2 4.
Hemisphe
cal
tradiatian
an surfaces af different arientatians
fot a central Eurapean
climate
(Streiche,
2002)
irradiation. The
r.ilrtc'r iucidcnt radiation ou thc south-facrng 45' tilted
suface
is
much
highel
than that
lbr
the horizonral suface.Vcrtical sulfices llcing south do
h:rve
l
ncarly
constant
irradiation
from
Marrh
to
Scptcmbcr, and
ncarlv
as mucl-r
irladiatron
in
rvinter-ls
surdrces
facing
south
rvith
a
45'tilt angle.Tivo-axis trackine
nrainly
increases
the
solar
yield in
sunrrrrer,
rvhile in whter
the
irr:rdiancc
is
sitnilar
to
a
45o slopc
flrcilg
south.
In
order
to
cover
the geographical
range
lor the
nuin
rnatkets
of solar-
conrbisystenrs,
it
rves decided
to
choose x
northern,
x
centr-:rl and
a southern
European
climatc for all iurther
investigations and simularions.
llcspectivel),,
thesc rverc:
.
Stockhohn.
Swcden
.
Zurich.
Sr,vitzerland
.
Carpcntras.
Fmncc.
Table 2.1
shorvs
the ch:rr acter istics of thc locations with respect
to
geographical
data,
design temperatures
(for
space
heating)
and
yearly
global
irradiation
(or.r
a
hor-izontal surlace).
Table
2 1.
Characteristics
of
the
lacatians
(Strcichet
et al.,
2A01)
Lonsitude
Helght
above
'ENt
ser level
Zurich
(CH)
Stockholm
(S)
5115
tl)5
8.5.13
-+
13
I 1
93lJ
.+1
1t)
t7
t+
r)5
11 31
59.3l
1a02
1088
981
Figure 2.5
shorvs the
global
solar irradiation and
arrbient
teulpemture o11 :r
long-
tetnl
a\rerage
nronlhly
basrs
lor the chosen
clinrates.
The
ditTcrences
bctrveen the
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14
SOLAR
HEATING
SYSTEIVS FOR HOUSES:
A DESTGN
HANDBOOK
FOR
SOrAR
COMB
SYSTEMS
9o
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6/7
THF SOIAR RFSOI]R'F 15
:
Globalsolarirradiance
_--''-
Ambient
lemperature
1000
900
800
700
600
500
400
300
200
100
0
4441
4465 4489
4513
4537
4561
4585
Hour of the
year
FigLlre 2.6. Haurly average values
at
glabal
trradtance and ambtent tempetature
far a summer
week in
Zurich,
generated
with
It4ETEONORM
(1999)
2.2 AVAILABILITY
OF CLIMATIC
DATA
Clinatic
data
lbr
anbient temperature and
global
solar uradiancc
(on
a
l-rotizontal
sut1ace)
is
ar-ailable
lor
a
rvide
range oflocrtions.
ln
Figur-e
2.3
it
nas shos,n that
both irradiation and tcnipcraturc
ditl,'r
Ii-om
placc
to
place
or,'er a rvide rarlge
o11
:r
lnonthly
basis
rnd
less o1r
a
,velrly
basis.
If
clillerent locations art
to
bc compaled,
it
is thcrefor-e necessxr-y
to
use
average
clinrate
d:rt:r.
For
simulating
solar combisysteurs
rvith onc to thrcc
days
ofrvatcr
storage, at least
hourl,v clini:rtic
dlta
is necessary
to
calculate
correctly thc behavioru ofthc storagc.
The
same
t),pe
of
data
is
needed
if the ctlect
of
the
ther-nul
lctive
m:rss of rhc
building
(the
storage ofexcc'ss er.rc'rgy during
the
day
fol
use at
night
to
reduce
rhe
heat
demand)
is
taken
into
considcration. One
ofthe
ploblerus
is
to find hourly
dara
that match lor-rg-term avcrages as rvell as
srandard
fluctuations (sunny
and
cloudy
wcather
situirtiolls
in
a
realistic statistical
disu ibutron, rvher-e irr-adiance.
lcnrpet:rtute. humidiq,,
u,ind spccd etc.
correspond rvith
each other).Tivo
mcthods
are
dcscribed in the literaturc.
2.2.1 fest Reference
Years
Tbst Rc-ll-lenceYears
iire
generated
by selecting tinlc
spans
(typically
one lllontl.r)
of
nleasrircd
climatic
data
liom
a
number
of
r-neasuled
yetrs
for
one
location
in
such
a rvay that
the
long
term
l]]oltthly
averages ofall
climatic data
for
tl-ris
location ate
matched.
Using
111easLrled
data
ensures that the
rveather
fluctuations
of
thc
regron
are
correctly rcplesented-
Of
course,
thc lirrks between
the
time
spans have
to
be
suroothed.
Llowever,
generating
TEst Rclelence Years
(TRY)
is
vcr-)
rinre
consl1rnillg.
Consequentll. rhey ate
olien
vely
expensive
(as
for.example
thc 12
available
Test RcGrenceYear-s for'()ermany).
Horvever, they
a,:e somctimes :rvailable
ficc
of charsc, :rs
lor
esarnple
the Typic:r1
MeteorologicalYears (TMY)
fot the
USA
E
=
o
2sE
209
t-
10
.lR
'i'r
+
'l
I * r ir i i i
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8/17/2019 Cap 2 the Solar Resource
7/7
'16
SOIAR
HEAT
NG
SYSTElvlS
FOR HOUSES:
A DES GN HANDBOOK
FOR SOTAR
COMB
SYSTEMS
lor
23.1
sites
(scc
l.rttp: / /rrcdc. nr e1.gov/sohr'/o1d
data/r'rsrdb/tmy2/).
In order to
have data available
for':r
rvhole countr-y,
it
has
to
be divrded
into
typical
rveather
zones,
fol rvhich
Test
RefelenccYeals
have
to be
developed.
2.2.2
Wealher data
generators
T}re second option is the use
ofrveather data
gencrator s. These
plogram
use lotrg-
terul
average
lnonthly data of
some kcy values
(norurally
l.llonthly aveuge
daily
global irradiation
and
ambienr
teDrperature)
and
gencrrte
hour-ly data,
using phvsical
and
statistical
approaches.
Well
knorvn
are
the
weathel
dat:r
geuerators
of
rhe
simulation
toolTRNSYS
(K1eir.r
ct a/., 1998) and
of
the Srviss
tool
METEONOM
(1999).The lancr
rvas
used
inTask
26.
Long-term monthly
averAge
rcnlpemtrues
can
be found at http://wwwtop-wetter.de/klinmdiagramme/rvelt.htt'u.
Worldrvide
irradiation
data can
be
found at http://rvrdc
mgo.nrel.gov/htln1/get-data-ap.html.
All
of
the
conlbisystenl sit'uulations
per-lbrmed
within
Task
26
needed
cr,'en
smaller
tirle steps
(dor,vn
to
one
ninulc) to
model the behaviottr
of
the
systerlls
correctl)'-
Thercfor ' the
hourly
values
rvere lineatly
interpo].ated, cnsuring
thar no
irradiance occurs
before or after sunset.
The
simulatior-rs
were set
up
in such a way that
othel
locatrons c:rn
be
easily
includcd
ifhourly
weather
data are available
in
the proper forrnar.
REFERENCES
BPAnroco.2002,
BPl,ro.d
.Sid/aJiir.rl R(rilrr ofiMvLl
Entrgy 20A1,BPAnoco.
London
METEONORM, 1999, Weathcr
I)ata
Generator.
METEOTEST,
Fabrikstr.rse
1'+,
CLI-3012
Bcrn, Srvitzerland;
n rv\r.meteonorrr1.cor11.
Streicher
W
2002, Lecture
book Sortacarrrrr;qicrrrt.-rr,r,g,
lnstitutc ofTherrml
Engineerin 1, Grlz
Univenity of
Teclmology.
Xlein,
SA,
Ilcckm:url
WA,
Mitchcll JW
Dufie
JA,
Duflie
NA,
Freeulan
TL, Mitchell
JC,
Braun
JE,
El.:rns BL, Kumner
JII
Urban
RE, Fiksel
A, Thornton
JWI
Ilhir
NJ, 1998,
7RAISYS,,4
Tintjicnt
Syltetn Sil
idtialr Prolra t
-
I:crsr,rrr
14.2
(as
used
in
prqect),
Soler
Energy Lrboretory,
University
of Wisconsin,
Mrdison,
USA.
ZAMG,
Zentrdirostalt
fiir Meteorologie ;rnd Geoclynarnik,Viennl,
Austrix, 2002.
INTERNET
SITES
FOR CLIMATE DATA
http://rredc.nrcl.gov/solar/o1d
data/nsrdb/nrU,2/:
flee TMY datr
sets
lor the USA.
http://1\,u,-$:rop-wetter.de/kliuracliaglramrre/telt.htrt: long
terrl
worid{,ide
uronthly
rve,-'rge
http:/,zrvrdc-ngo.nrel.gov/lrtrrrl/get
dara-ap.htni: rlorldu'ide irradirrion
data.