Arno Smets

Introduction to Solar EnergySolar Light II

Week 1.6.2

`

(Source: NASA)

Atmosphere~ 8,000km

Atmosphere

Earth’s Diameter12,800km

Solar Constant:Entry point into atmosphereIntensity ~ 1,350 W/m2

Wavelength (nm)

250 500 750 1000 1250 1500 1750 2000 2250 2500

5800 K Blackbody Spectrum

0

0.5

1

1.5

2

2.5

Sunlight Top of the Atmosphere

InfraredVisible

UV

Spe

ctra

l Po

wer

Den

sity

(W/m

2/n

m)

Extraterrestrial solar spectrum

Extraterrestrial and terrestrial solar spectrum

Wavelength (nm)

250 500 750 1000 1250 1500 1750 2000 2250 2500

5800 K Blackbody Spectrum

Radiation at Sea Level

Absorption Bands

H2OCO2H2O

H2O

H2O

0

0.5

1

1.5

2

2.5

Sunlight Top of the Atmosphere

InfraredVisible

UV

Spe

ctra

lIrr

adia

nce

(W/m

2/n

m)

H2O

O2

O3

4% 20% 6%Incoming SolarRadiation 100%

19% Absorbedby Atmosphereand Clouds

Reflected byAtmosphere

Reflected byClouds

51% Absorbed at Surface

Reflected fromSurface

Losses in Solar Radiation

Sunlight

Atmosphere

Sunlight

Air mass

YX

q

1

cAM

osq

Irradiance and spectral power density for AM1.5 2.00

1.75

1.50

1.25

1.00

0.75

0.50

0.25

0.00 00 500 1000 35001500

AM1.5

Irra

dia

nce

I (W

m-2

)

Wavelength (nm)

P(l

) (W

m-2

nm

-1)

2000 2500 3000 4000

200

400

600

800

1000

hc)(P)(l

ll

Spectral Photon Flux and Spectral PowerDensity

Photon Flux and Spectral Photon Flux

l

ll0

d)(

Relation Irradiance and spectral power density for AM1.5

5

4

3

2

1

00 500 1000 350

01500

AM1.5

Ph

oto

n flu

x (1

02

1s-1m

-2)

Wavelength (nm)

Spec

tral

ph

oto

n f

lux

(10

18s-1

m-2

nm

-1)

2000 2500 3000 4000

5

4

3

2

1

0

1 sun hour = 1 kWh/m2 = 1000 W/m2 x 1 hour

Solar irradiation on Earth

Nominal power Module 100 Wp

(power generated under 1000 W/m2, AM1.5)

Solar irradiation on Earth

The Netherlands: 2.7 sun hours/day/year

Solar irradiation on Earth

Output per day:

100 Wp x 2.7 sunhours =270 Wh Per year: 98.6 kWh

Solar irradiation on Earth

40003000200010005004003002001000.0

0.2

0.4

0.6

0.8

1.0

Res

po

nse

[ar

bit

rary

un

its]

Wavelength [nm]

Clear Hazy Cloudy

figure 3: spectral shift in diffuse irradiance with sky type

UVB UVA Visible Infrared

Diffu

se R

adiatio

n

Glo

bal

, Dif

fuse

, Dir

ect,

Atm

osp

her

ic[W

/m2]

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 230

100

200

300

400

500

600

700

800

900

1000

BSRN-Station Lindenberg, 05-03-2004

Source: DWD, Meteorologisches Observatorium Lindenberg

diurnal variation of irriadiance on 05-03-2004

Global Diffuse Direct Atmosphere

Hour [UTC]

UoutThermopile

Heatsink

Black Coating

Dome

Glo

bal

, Dif

fuse

, Dir

ect,

Atm

osp

her

ic[W

/m2]

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 230

100

200

300

400

500

600

700

800

900

1000

BSRN-Station Lindenberg, 05-03-2004

Source: DWD, Meteorologisches Observatorium Lindenberg

diurnal variation of irriadiance on 05-03-2004

Global Diffuse Direct Atmosphere

Hour [UTC]

Glo

bal

, Dif

fuse

, Dir

ect,

Atm

osp

her

ic[W

/m2]

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 230

100

200

300

400

500

600

700

800

900

1000

BSRN-Station Lindenberg, 06-03-2004

Source: DWD, Meteorologisches Observatorium Lindenberg

diurnal variation of irriadiance on 06-03-2004

Global Diffuse Direct Atmosphere

Hour [UTC]

`

(Source: NASA)