Environmental Controls. Daylighting Design & Analysis. Orientation and Slope. Lecture 18

Transcription

1 Environmental Controls Lecture 18 Daylighting Design & Analysis Design Strategies Glazing and Reflectors Sidelighting Analysis Method Daylighting Design & Analysis Orientation and Slope Vertical vs. Horizontal Time of year Sun position DL-5 F p. 79 1

2 Daylighting Components SC=Sun + Sky IRC 1 IRC2 ERC S: F p. 598 Daylighting Factor (DF) The quantity of interior illuminance on a horizontal work plane expressed as a percentage of illuminance of an exterior unobstructed horizontal plane DF (%) = (E INT /E EXT ) x 100 Daylighting Factor (DF) If E INT is 20 foot-candles and E EXT is 1000 foot-candles, then what is the daylighting factor? DF(%)= (E INT /E EXT ) x 100 DF (%)=(20/1000) x 100 DF (%)=2.0% 2

3 Lines of similar lighting levels Expressed as DF Isolux Contours Darwin College Library, Cambridge, England Isolux Contours Example E EXT = 2000 fc 1: 20 fc 2: 60 fc 3: 100 fc 4: 40 fc 5: 80 fc 6: 140 fc 7: 20 fc 8: 60 fc 9: 100 fc DF(%)= (E INT /E EXT ) x 100 Isolux Contours Example E EXT = 2000 fc 1: 20 fc DF=1 % 2: 60 fc DF=3 % 3: 100 fc DF=5 % 4: 40 fc DF=2 % 5: 80 fc DF=4 % 6: 140 fc DF=7 % 7: 20 fc DF=1 % 8: 60 fc DF=3 % 9: 100 fc DF=5 %

4 Isolux Contours Example E EXT = 2000 fc 1: 20 fc DF=1 % 2: 60 fc DF=3 % 3: 100 fc DF=5 % 4: 40 fc DF=2 % 5: 80 fc DF=4 % 6: 140 fc DF=7 % 7: 20 fc DF=1 % 8: 60 fc DF=3 % 9: 100 fc DF=5 % Lines of similar lighting levels Expressed as DF Isolux Contours Darwin College Library, Cambridge, England Illumination Gradient Ludwig Museum, Koln, Germany An illumination gradient through a section 4

5 Design Strategies Selection Parameters Daylight availability Task orientation Space orientation 10 Ceiling 30 Work plane Daylighting Graphs DL-5: F10-2 p. 80 5

6 Solid Overhang South Facing Walls a: translucent glazing b: horizontal overhang c: 30º sloped clear glazing d: 45º sloped clear glazing DL-5: F10-5 p. 82 Diffusing Awnings South Facing Walls a: translucent glazing b: translucent awning clear glazing c: white vertical slatted awning, clear glazing d: white, horizontal slatted awning, clear glazing DL-5: F10-6 p. 82 Light Shelves W: With light shelf WO: Without light shelf DL-5: F10-18 p. 89 6

7 Effect of skylight above roof a: flat horizontal b: half-round barrel, white opaque ends c: steeply sloped A-frame, white opaque ends Skylights Typographic Error In Reading DL-5: F10-21 p. 91 Roof Monitors North-South Monitors a: translucent panel b: north monitor, clear glazing c: south monitor, translucent glazing DL-5: F10-30 p. 95 Roof Monitors Sun Control Baffles/Louvers Light Wells DL-5: F10-35 p. 97 7

8 Roof Monitors Graphic Design Approach DL-5: F10-37 p. 98 Glazing & Reflectors Fenestration Window or Fenestration? 8

9 Clear Glazing Maximum VLT DL-5: F11-1 p. 105 Gray/Bronze Glazing DL-5: F11-2 p. 106 Gray glass preferred where color rendition is important Heat Absorbing Glazing DL-5: F11-3 p. 107 Green is more common Blue is becoming more available 9

10 Solar IR Reflective Film DL-5: F 11-6 p. 109 Low-E Glass Multiple Glazing Combinations of individual paned glazing Mylar/Film layer Inert gas (argon or krypton) Superwindow Exotics LED Windows Aerogels Kalwall Prototype House and Studio Thomas Herzog 10

11 Sidelighting Method Subscripts w=window k=sky g=ground u=sun Parameters R g T g 11

12 Illumination (E) E kw E kg E uw E ug E kuw E kug Illumination from sky on window Illumination from sky on ground Illumination from sun on window Illumination from sun on ground Illumination from sky and sun on window Illumination from sky and sun on ground Illumination (E) E gw E kwp E gwp R g A g T g Illumination from ground on window Illumination from sky (and sun) on work plane Illumination from ground on work plane Reflectance of ground surface Window area of transmittance Transmittance of glass Coefficients of Utilization (C,K) C os and K os C cs and K cs C us and K us C sv and K sv C ug and K ug C gv and K gv overcast sky clear sky uniform sky sky with venetian blind uniform ground ground with venetian blind 12

13 Daylighting Components Illumination on window E kuw = E kw + E uw Illumination on ground E kug = E kg + E ug Daylighting Components Illumination from sky (and sun) on work plane E kwp = E kuw x A g x T g x C x K Daylighting Components Illumination from ground on window E gw = E kug x R g x 0.5 Illumination from ground on work plane E gwp = E gw x A g x T g x C x K 13

14 Total Daylighting Components Illumination from ground on window E TOT = E kwp + E gwp 14