Christina McHugh Building Services Engineering Dublin Institute of Technology Designing for Natural Light Benefits of Natural Light Type of Daylight Available Daylight Factor Room Dimensions ID: 256039
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Slide1
Natural Lighting
Christina McHugh
Building Services Engineering Dublin Institute of TechnologySlide2
Designing for Natural Light
Benefits of Natural Light
Type of Daylight Available
Daylight Factor
Room Dimensions
Thermal ImpactSlide3
Benefits of Natural Light
Savings in electricity
Electric Lighting 12W/m
2
Mood and productivity
General well-being
Improved visual performance
Enhances building aestheticsSlide4
Direct -
Light shining
directly from the sun.
Diffuse -
Light given off by the sky.
Clouds + Pollutants
Direct
Diffuse
Daylight Available Slide5
Daylight Factor
– ratio of daylight inside to daylight outside
Greater than 5 %
Between 2% and 5 %
Less than 2 %
Gloomy appearance
Electric lighting needed
Predominantly daylit appearance
Some supplementary electric lights needed
Strongly daylit, no electric lighting needed
High risk of overheating
AppearanceSlide6
IRC
SC
ERC
SC = Sky Component
ERC = Externally Reflected Component
IRC = Internally Reflected Component
P
Daylight Factor = SC + ERC + IRC
Daylight FactorSlide7
Overall Reflectance, R
Total Surface Areas, A
Transmittance of Glazing, T
Window Area,
A
w
(%)
(m
2
)
Angle of Visible Sky,
θ
Daylight FactorSlide8
Room Dimensions
Window height
∝
Depth of light
Room depth
≤
6
metresSlide9
Thermal Impact of Windows
Size and Type of Glazing
Summer
Low daylight factor
Overheating
Low solar gain, Low DF
Thermal barrier, Prevents overheating and glare
Winter
Low daylight factor
Excessive heat loss
Insufficient daylight
Low heat loss,
Good daylight factor
Reflective
Low emissivity
Large area
Small areaSlide10
Thermal Impact of Windows
Shading Devices
Summer
Shield high angle summer sun
Prevent glare and overheating
Internal Blinds
External Shading
Winter
Admit low angle winter sun
Fully retractable for maximum daylightSlide11
Windows provide entrance hall with side lighting
Placed behind a large glass wall to overlook Trafalgar Square
Sainsbury Wing
National Gallery
LondonSlide12
Sainsbury Wing
National Gallery
London
Automatically adjusting louvres
Combination of the artificial and natural light
650,000
kilolux
hours in a yearSlide13
Conclusion
Savings in electricity
Improved mood
Aesthetically pleasing
Type of Natural Light
Direct & Diffuse
Daylight Factor
2% - 5%
Room Dimensions
Thermal Impact
30% Glazing, Low emissivitySlide14
Thank You for Listening.
Natural Lighting
Christina McHugh
Building Services Engineering
Dublin Institute of Technology