lec7 - Sky type Clear Milky-white Partly cloudy Whitish...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Sky type Clear Milky-white Partly cloudy Whitish Light grey Dark grey Dark Sun Shiny Clear Partly veiled Veiled Still visible Barely visible Invisible Global radiation [W/m 2 ] 800 to 900 600 to 800 300 to 700 250 to 400 200 to 300 100 to 200 20 to 100 Diffuse component 10 to 20% 20 to 40% 20 to 50% 40 to 80% 50 to 100% 75 to 100% 100% Direct and diffuse components of daylight Direct and diffuse components of daylight Sky models for diffuse component 3 4 5 2 1 0.5 1 1 1.5 2 2.5 3 N N N N S S S S E E E E O O O O Z Figure by MIT OCW. Sky models Overcast sky 7000 (winter) to 20000 (summer) lux on ground uniform L( )=L z 1 1 Sky models Overcast sky 7000 (winter) to 20000 (summer) lux on ground CIE overcast L( )=L z (1+2sin )/3 1 80 70 60 50 40 30 20 10 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 80 70 60 50 40 30 20 10 3 Sky models Clear sky 30000 (winter) to 100000 (summer) lux on ground Sky models Clear sky CIE clear sky model L = fction of zenith luminance and sun position 3 4 5 2 1 0.5 1 N S E O Figure by MIT OCW. Sky models Clear sky CIE clear sky model L = fction of zenith luminance and sun position Perez All Weather sky model (generalization of CIE clear sky) L = fction of date, time, direct and diffuse illuminances, and 5 coefficients L fully defined if diffuse and direct irradiance are known Daylighting metrics Static metrics Daylight Factor DF [%] DF = (E point /E outside horizontal ) * 100% (only defined for overcast skies!) E outside horizontal E point Figure by MIT OCW. Daylighting metrics Static metrics Daylight Factor DF [%] DF = (E point /E outside horizontal ) * 100% (only for overcast skies!)) * 100% (only for overcast skies!...
View Full Document

Page1 / 25

lec7 - Sky type Clear Milky-white Partly cloudy Whitish...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online