Environmental Controls I/IG
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. 10-1 p. 79
1
Daylighting Components
SC=Sun + Sky
IRC1
IRC2
ERC
S: F.14.18 p. 590
Daylighting Factor (DF)
The quantity of interior illuminance on a
horizontal work plane expressed as a
percentage of illuminance of an exterior
unobstructed
b t
t d horizontal
h i
t l plane
l
DF (%) = (EINT/EEXT) x 100
Daylighting Factor (DF)
If EINT is 20 foot-candles
and EEXT is 1000 foot-candles,
then what is the daylighting
y g
g factor?
DF(%)= (EINT/EEXT) x 100
DF (%)=(20/1000) x 100
DF (%)=2.0%
2
Isolux Contours
„
„
Lines of similar
lighting levels
Expressed as DF
Darwin College Library, Cambridge, England
Isolux Contours Example
EEXT= 2000 fc
1+
1: 20 fc
2: 60 fc
3 100 fc
3:
f
4: 40 fc
5: 80 fc
6: 140 fc
7: 20 fc
8: 60 fc
9: 100 fc
2+
3+
4+
5+
6+
7+
8+
9+
DF(%)= (EINT/EEXT) x 100
Isolux Contours Example
EEXT= 2000 fc
1: 20 fc
2: 60 fc
3 100 fc
3:
f
4: 40 fc
5: 80 fc
6: 140 fc
7: 20 fc
8: 60 fc
9: 100 fc
DF=1 %
DF=3 %
DF 5 %
DF=5
DF=2 %
DF=4 %
DF=7 %
DF=1 %
DF=3 %
DF=5 %
1+
2+
3+
4+
5+
6+
7+
8+
9+
3
Isolux Contours Example
EEXT= 2000 fc
1: 20 fc
2: 60 fc
3 100 fc
3:
f
4: 40 fc
5: 80 fc
6: 140 fc
7: 20 fc
8: 60 fc
9: 100 fc
DF=1 %
DF=3 %
DF 5 %
DF=5
DF=2 %
DF=4 %
DF=7 %
DF=1 %
DF=3 %
DF=5 %
1
3
5
2
4
7
1
3
5
2
6
4
Isolux Contours
„
„
Lines of similar
lighting levels
Expressed as DF
Darwin College Library, Cambridge, England
Illumination
Gradient
Ludwig Museum, Koln, Germany
An illumination
gradient through
a section
4
Design Strategies
Selection Parameters
Daylight availability
Task orientation
Space orientation
Daylighting Graphs
10’ Ceiling
30” Work plane
DL-5: F10-2 p. 80
5
South Facing Walls
Solid Overhang
a: translucent glazing
b: horizontal overhang
c: 30º sloped clear
glazing
d: 45º sloped clear
glazing
DL-5: F10-5 p. 82
South Facing Walls
Diffusing Awnings
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
Skylights
Effect of skylight
above roof
a: flat horizontal
b: half
half-round
round barrel
barrel,
white opaque ends
c: steeply sloped
A-frame, white
opaque ends
Typographic Error In ReadingÆ 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
Roof Monitors
Graphic Design Approach
DL-5: F10-37 p. 98
Glazing & Reflectors
Fenestration
Window or Fenestration?
8
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
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
Sidelighting Method
Subscripts
w=window
k=sky
g g
g=ground
u=sun
Parameters
Rg
Tg
11
Illumination (E)
Ekw
Ekg
Euw
Eug
Ekuw
Ekug
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)
Egw
Ekwpp
Egwp
Rg
Ag
Tg
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)
Cos and Kos
Ccs and Kcs
Cus and Kus
Csv and Ksv
Cug and Kug
Cgv and Kgv
overcast sky
clear sky
uniform sky
y
sky with venetian blind
uniform ground
ground with venetian blind
12
Daylighting Components
Illumination on window
Ekuw = Ekw + Euw
Illumination on ground
Ekug = Ekg + Eug
Daylighting Components
Illumination from sky (and sun) on
work plane
Ekwp = Ekuw x Ag x Tg x C x K
Daylighting Components
Illumination from ground on window
Egw = Ekug x Rg x 0.5
Illumination from ground on work
plane
Egwp = Egw x Ag x Tg x C x K
13
Total Daylighting Components
Illumination from ground on window
ETOT = Ekwp + Egwp
14