cap02-Sun and radiation

Page 1

Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

Sun, earth and radiation


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

The sun and the earth

150.000.000 Km

SUN

EARTH R= 6.400 Km

R= 700.400 Km


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

EARTH

R= 6.400 Km

R= 700.400 Km


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

EARTH

R= 700.400 Km


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

R= 6.400 Km

R= 700.400 Km


by Moisès Morató

Architecture and solar energy Energy and environment

0,53º (2D)

0,00027 Sr (3D)

22.995 “suns” / hemisphere

The sky can be filled by near 23.000 suns.


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

Solar radiation.


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The power of sun: 570.000.000 ton de H2 a 560.000.000 ton de He per second = 400.000.000.000.000.000.000 de MW

R= 6.400 Km

1.400 W/m2 of power at 150 milions of Km

R= 700.400 Km


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Absolut radiation of the estratosferic radiation in the earth:

1. 4 0 0 W / m2

of power


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The movement of earth around the sun.


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Inclination of axis of rotation

N

W

E

1 rev. at day

S

Source: M. Morat贸.


by Moisès Morató

Architecture and solar energy Energy and environment

Inclination of axis of rotation Inclination of axis:

1 rev. at day

Constant = 23,45º

N W E

23,45º

Source: M. Morató.

S Ecliptic plane


by Moisès Morató

Architecture and solar energy Energy and environment

day/night 1 revolution every day

Ecliptic plane

1 revolution every 365’25 days The seasons Image: M. Morató.


by Moisès Morató

Architecture and solar energy Energy and environment

Declination

Summer

Winter

N

+ 23,45º

N Ecliptic plane

S

Source: M. Morató.

S

- 23,45º


by Moisès Morató

Architecture and solar energy Energy and environment

Declination

+ 23,45 º

+ 23,45 º

- 23,45 º

Source: M. Morató.


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The seasons

summer (north hemispheri)

Source: M. Morat贸.

winter (north hemispheri)


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The seasons

Position in summer (north hemispheri) at 12:00 at noon Source: M. Morat贸.


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The seasons

Position in summer (north hemispheri) 12:00 midnight Source: M. Morat贸.


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The seasons

Position in winter (north hemispheri) in the 12:00 at noon Source: M. Morat贸.


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The seasons

Position in winter (north hemispheri) at 12:00 midnight Source: M. Morat贸.


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

Which is the movement of the Sun from the Earth ?

Source: M. Morat贸.


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

The movement of the Sun from the earth

The Cercasol tool (findsun)

Source: M. Morat贸.


Architecture and solar energy Energy and environment

ex: How to follow the sun in BCN ?

Source: M. Morat贸.

by Mois猫s Morat贸


Architecture and solar energy Energy and environment

1.- Put the axis in direction North

Source: M. Morat贸.

by Mois猫s Morat贸


Architecture and solar energy Energy and environment

2.- Inclinate the axis = latitude of place = 41潞

Source: M. Morat贸.

by Mois猫s Morat贸


Architecture and solar energy Energy and environment

3.- Incline the arrow = declination of the day

N= day of year (N =1 of January) Source: M. Morat贸.

by Mois猫s Morat贸


by Moisès Morató

Architecture and solar energy Energy and environment

The 3 special positions of the year declination (+ 23,45º)

Soltice of summer (21 June)

Source: M. Morató.

declination (0º)

Equinox spring and autumn (21 March/ 22 September)

declination (- 23,45º)

Soltice of winter (21 december)


Architecture and solar energy Energy and environment

4.- Rotate (left rotation): 1 revolution at day.

Source: M. Morat贸.

by Mois猫s Morat贸


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Polar

springautumn

summer

winter

latitude South 1 turn at day

Source: M. Morat贸.


by Moisès Morató

Architecture and solar energy Energy and environment

declination (- 23,45º)

12:00 solar (Noon)

Ex: Track on solstice of winter (41 º lat North)

South West

Est

North Source: M. Morató.


by Moisès Morató

Architecture and solar energy Energy and environment

declination (0º)

12:00 solar (Noon)

Ex: Track on equinocces (41º Lat North)

South West

Est North Source: M. Morató.


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

12:00 solar (Noon)

Ex: Track on solstice of summer (41 潞 lat North) South West

Est North Source: M. Morat贸.


by Moisès Morató

Architecture and solar energy Energy and environment

N

S

N

S

N

S

N

S

Ex: Position of the “Cercasol” at 23 of December in others places on the earth Source: M. Morató.

S


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

The nature of the radiation on earth

Source: M. Morat贸.


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Meaning of power and energy radiation Radiation Power units

W / m2

mean

Instantaneous energy

Radiation Energy kWh / m2 captured energy in a interval of time

Power (W/m2) Power at time t2 is

Z (kWh/m2)

X (W/m2)

Energy captured between time t1 and t2 is

Time (s) t1 Source: M. Morat贸.

t2

t2


by Mois猫s Morat贸

Architecture and solar energy Energy Sun, earth andand environment radiation

The nature of the radiation on earth

1. 4 0 0 W / m2

Image: Google earth.

of power


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Distribution of the solar radiation spectrum:

Intensity

1. 4 0 0 W / m2 UV

visible

of solar power

IR

Short

0,4

wave

0,7 0,5

1,0

1,5

2,0

2,5

3,0

位 (碌m)


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Stratospheric radiation and Radiation at level of the sea in a clear day 1. 4 0 0 W / m2

1.400 W/m2

of power

4%

9 0 0 W / m2

of power

48%

900 W/m2

2%

Image: Google earth.

48%

40%

58%


Architecture and solar energy Energy and environment

Source: www.oksolar.com.

by Mois猫s Morat贸


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

< 2 kWh/m2

2,5 kWh/m2

4,4 kWh/m2

3,9 kWh/m2

7,2 kWh/m2

4,8 kWh/m2

Average daily radiation on the earth: 170 W/m2/day = 4 kWh/m2/day Source: www.oksolar.com.


by Moisès Morató

Architecture and solar energy Energy and environment

Theoretical distribution of monthly radiation by latitude (kWh/m2/day) 8

+ 90º

4

0

+ 90º

8

+ 60º

4 0

+ 60º

8

+ 30º

4

+ 30º

0

8

+ 0º - 30º - 60º

+ 0º

4 0 8

- 30º

4 0 8

- 90º

- 60º

4 0 8

- 90º

4 0 J

Source: NASA.

F

M

A

M

J

J

A

S

O

N

D


Architecture and solar energy Energy and environment

Direct and diffuse radiation

Source: NASA.

by Mois猫s Morat贸


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

Direct and diffuse radiation Source of direct radiation (sun)

Source of diffuse radiation

Source of reflected radiation Source: Traimar


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Direct rad. + Diffuse rad. + Reflected rad. = Global radiation

Source: Traimar


by Moisès Morató

Architecture and solar energy Energy and environment

Usually reflected radiation is lower than direct and diffuse radiation then …

Global radiation = Direct rad. + Diffuse rad. + Reflected rad.

Source: Traimar


Architecture and solar energy Energy and environment

Diffuse radiation

In the atmosphere appears the diffuse radiation Source: Google.

by Mois猫s Morat贸


Architecture and solar energy Energy and environment

Direct and diffuse radiation

Diffuse radiation appears by interaction of direct radiation against atmosphere molecules Source: Google

by Mois猫s Morat贸


by Moisès Morató

Architecture and solar energy Energy and environment

Direct and diffuse radiation in a homogeneous clouded sky

100 %

Source: Moisès Morato.

www.cercasol.com


by Moisès Morató

Architecture and solar energy Energy and environment

Direct and diffuse radiation (W/m2) in homogeneous clouded skies 100 %

A

80 %

B

D Source: Moisès Morato.

www.cercasol.com

C 20 %

40 %

E

60 %


Architecture and solar energy

by Mois猫s Morat贸

Energy and environment

Evolution of direct and diffuse radiation (kWh/m2/day) in homogeneous clouded skies 9

Irradiation (kWh/m2/day)

8 7 6 5 4 3 2 1 0 A (100 %) B (80 %) C (60 %) D (40 %) E (20 %)

Source: M. Morat贸. www.cercasol.com.


by Moisès Morató

Architecture and solar energy Energy and environment

Real graphs of direct and difusse radiation

Source: UAB (Universitat de Física)

A fully clear day (june 2006 BCN)


by Moisès Morató

Architecture and solar energy Energy and environment

Real graphs of direct and difusse radiation

clear day cloudy day Source: UAB (Universitat de Física)


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Diffuse radiation

Intensity of diffuse radiation in sky can be higher o lower than the sky without clouds. Source: M. Morat贸.


by Mois猫s Morat贸

Architecture and solar energy Energy and environment

Diffuse radiation

Intensity of diffuse radiation in sky can be higher o lower than the sky without clouds. Source: M. Morat贸.


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