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.


2/7

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

.

[email protected]

;

?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


3/7

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


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


5/7

14

SOLAR

HEATING

SYSTEIVS FOR HOUSES:

A DESTGN

HANDBOOK

FOR

SOrAR

COMB

SYSTEMS

9o


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


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.

Cap 2 the Solar Resource

Documents