Title: Instructor:
1Lighting design In Architecture
University of Palestine College of Applied Engineering Urban Planning Department of Architecture, Interior Design Planning
DAYLIGHT
- Instructor
- M Sc. Eng. Nagham Ali Hasan
2nd lecture- 2nd semester 2008/2009
2DAYLIGHT
- Importance Of The Daylight
- Daylight Sources
- Daylight Components
- Daylight Strategies
- Daylight Calculations
3Three Components of DaylightingDesign
- ?? Aesthetics (light and shadow, color, view)
- ?? Human performance (psychology and biology
benefits) - ?? Energy (sustainable design)
4Daylight for the beauty !
- How much daylight (footcandles- lux)
- Quality of light (glare and luminance ratios)
5Sky conditions
- Clear sky Sky that is less than 30 cloud cover.
Overcast sky Sky completely covered by clouds,
no sun visible
- Cloudy sky Sky having more than 70 cloud cover.
6Typical illuminances E and luminances under
daylight and electric light.
7Components of the Natural Light
- There are three separate components of the
natural light that reaches any point inside a
building
- Sky Component (SC) - Directly from the sky,
through an opening such as a window. - Sky Component (SC) depends on
- Width of the window
- Distance between the point and window
- SC varies from 0.01 to 15
Fig Components of the Natural Light
8- Externally Reflected Component (ERC) - Reflected
off the ground, trees or other buildings. - Externally Reflected Component (ERC) is small.
- The luminance of obstrction is taken as 10-20
that of the sky - Internally Reflected Component (IRC) - The
inter-reflection of 1 and 2 off surfaces within
the room. - Internally Reflected Component (IRC) is a half
of SC and is therefore significant
9Daylight Component
- Daylight factor defined as
- The ratio of daylighting illumination on a
horizontal point indoors to the horizontal
illumination outdoors, expressed as a percentage.
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11Key Architectural Issues
- The daylight factor in a particular building
space depends upon a number of design factors
including - size of daylight apertures (windows, skylights,
etc.) - location of daylight apertures (sidelighting,
toplighting, etc.) - access to daylight (considering the site,
building, and room - contexts)
- room geometry (height, width, and depth)
- location of the point of interest relative to
apertures - visible transmittance (VT) of glazing
- reflectances of room surfaces and contents
- reflectances of exterior surfaces affecting
daylight entering the aperture - the effects of daylighting enhancements (such
as light shelves).
12- The daylight illuminance at any given point in a
building depends upon the factors noted above
and - the buildings global location and prevailing
climate - the time of day/month/year
- the current sky conditions.
Daylight factor versus illuminance as a measure
of daylighting. The illuminance values will
change throughout the day, while the daylight
factors will be reasonably constant throughout
the day (under similar sky conditions).
13Daylight systems
- How redirect the daylight into spaces??
- Windows
- Saw-tooth
- Monitors
- Skylight
- Atrium
14Vertical windows
- Useful daylighting will only reach a distance of
2.5 times the height of the top of the window
above the work plane (usually taken at a desk
height of 60 cm - In a standard office building with a window
height of 2.5 m, this means a maximum of about
5-7 metres.
Cross section showing lighting distribution from
a single-sided window installation
15Windows
The Effect of Windows on Two Sides of a Room on DF
16- In overcast sky condition
- Long thin horizontal windows will not prvide as
much light per unit area as taller more vertical
windows
The Effect of Window Height on DF
17- Fig. shows how the DF varies across a room
using two types of windows, both having the some
total area - (a) is for three tall windows, and
- (b) is for one long, high-level window.
- Window (a) will give a good open view, but (b)
will provide more even daylight illumination.
The Effect of Window Shape on DF
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19- Cross section showing how illumination vectors
become more horizontal as sidelight travels
deeper into a space
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21Light shelf ceiling reflectors
22Minimum Reflectance Values
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24Skylight
Double-glazed units and a range of louvered
systems should be used wherever possible to
reduce conducted heat losses. Appropriate no. of
units is 5 of ceiling area
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27English court
28 29Saw-tooth
30Saw-tooth
- Saw-tooth preferred dimension
31Rooflights at Crookham Church School.
(Architects Edward Cullinan Architects.)
Mt. Airy Public Library
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33Kimbel Art Museum - Louis Kahn
Use light reflectors under the light system to
defuse the light through the internal space
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35Atrium
36Mashroom column. Frank loyd Write
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38Celestins Square (The Car Bark) Central Shaft
-Germany
39Artificial light Daylight factor
- The required quantity of artificial light input
is to achieve an illumance at the rear of the
room comparable to, but slightly less than, the
daylight illuminance near the window. For example
Artificial light (lux) Daylight factor
250 0.5
500 1.0
750 1.5
1,000 2.0
40Innovated Daylighting Systems
- Light Pipes
- The system consists of
- COLLECTOR /CONCENTRATOR
- TRANSPORT SYSTEM
- EMITTER
The Light Pipe Principle
41Light Pipes
42Representative measured light levels in tall
shafts at De Montfort Universitys Queens
Building.
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45London Art museum
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48 49The Heliostat System
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?????.
The Heliostat System
50The Heliostat System
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555-
(movable-orientable Glass Louvres)
56 The Glass Louvers may be installed as a movable
or fix system
57Daylighting calculations
Where, T is the diffuse light transmittance
of the glazing including the effects of dirt,
blinds, obstructions and coverings Aw is the
window area (m2) ? is the vertical angle
subtended at the centre of the window by
unobstructed sky A is the total area of
indoor surfaces (ceiling, walls and floor,
including glazing) R is the area-weighted
average reflectance of ceilings, walls and
windows.
58ExampleDaylighting calculations
- An office room with 43m , height 2.5m assume
that T 0.75 and - Reflectance of the ceiling 0.7
- Reflectance of the wall 0.5
- Reflectance of the window 0.1
- Reflectance of the floor 0.3
59- The total area of the room is 59 m2. The average
reflectance is area weighted in the following
way - (R side wall) (Area side wall) (0.5)(3)(2.5)
3.75 - (R side wall) (Area side wall) (0.5)(3)(2.5)
3.75 - (R back wall) (Area back wall) (0.5)(4)(2.5)
5.00 - (R front wall) (Area front wall) (0.5)(10 -
2.25) 3.88 - (R window) (Area window) (0.1)(2.25) 0.23
- (R ceiling) (Area ceiling) (0.7)(4)(3) 8.4
- (R floor) (Area floor) (0.3)(4)(3) 3.6
-
- Total 28.61
60Indicative daylight factors
.
61- (a) Sidelighting average
- DF 20(Ag/Af)
- (in the area adjacent to the window to about
2Hwin away). - (b) Horizontal skylight
- DF 50(Ag/Af),
- where DF is the daylight factor as a percentage,
Ag is the area of glazing (m2), Af is the area of
floor to be lighted (m2), - and Hwin is the window head height (m).