Daylighting

Openings

Levente Filetóthfiletoth@egt.bme.hu

Dpt. of Building Energetics and ServicesK.231.

www.egt.bme.hu/filetoth

Daylighting Luminaires = OpeningsLight sources

• direct sunlight• diffused light of the sky• reflected light

Luminaires• Openings:‣ side-lights (such as

windows)‣ skylights• Special daylighting

systems

Openings

• Side lights (windows)

• Skylights

Openings

• Daylight enters through the transparent surfaces of the openings into the interior

• Openings are the those structural units that contains such transparent surfaces

Openings • Openings let the daylight in,

while also modify the characteristics of daylight

• Their orientation determines the part of the sky hemisphere that will provide daylight

• Their structure will effect the illuminance distribution in the interior

Openings • Integral part of the building

envelope and of the building structure

• Most comply with several disciplines (energy, structure, building construction) besides providing natural light

• Provide visual connection with the exterior

Openings

Structural aspects• Widows (side lights),• Skylights• Transparent walls• Transparent ceilings• Other transparent

elements of the building shell and structure

Openings

Main structural parts of openings (considering daylighting)

• Transparent surfaces• Obstructions (frame)• Reflecting surfaces

Openings

Main structural parts of openings (considering daylighting)

• Transparent surfaces• Obstructions (frame)• Reflecting surfaces

Translarent wallsTypical efficiency values:

single-layered, transparent glass: cca. 0,7double-layered, transparent glass: cca. 0,6glass blcoks: cca. 0,3

Further reduction of efficiency due to:

• dirt: 25-30%

Skylights

Linear   Spot

Skylights

• Located above the ceiling

• Inclination of transparent surface: 0-90°

• Arbitrary orientation• Layout:

• Linear • Spot

Linear skylights

Geometry:

• Saw-tooth• Horizontal• Monitor• Picthed

Saw-tooth

Saw-tooth (0-90°):• Efficiency:

90°: 0,1 … 0,260°: 0,2 … 0,2530°: 0,25 … 0,35

• Northern orientation ensures protection agains direct sunlight!

Horizontal

Horizontal:• Efficiency:

0,25 … 0,4

• Protection must be provided against direct sunlight!

Monitor

Monitor (60-90°):Efficiency:

symm. 90°: 0,1 - 0,2assymm. 90°: 0,15 - 0,2sloping gl.: 0,2 … 0,35

• Protection must be provided against direct sunlight!

Pitched

Pitched (cca. 45°):• Efficiency

0,3 … 0.4

• Protection must be provided against direct sunlight!

Spot skylights

Geometry:

• Dome• Pyramid• Prism

Dome

Dome:• Efficiency:

0,2 … 0.4

• Protection must be provided against direct sunlight!

Prism

Prism (cca. 45°):• Efficiency

0,25 … 0.35

• Protection must be provided against direct sunlight!

Spot Skylights

Spot Skylights

Spot Skylights

Spot Skylights

Geometry:

• Saw-tooth• Horizontal• Monitor• Picthed

Prisms Dayligh,ng  tubes

Dayligh,ng  systemsShading  devices,  Light-­‐shelves

Daylighting systems

Prisms, Light-selves, Shading devices

PrismsLight-selves

Prisms, Light-selves, Shading devices

Prisms, Light-selves, Shading devices

Prisms, Light-selves, Shading devices

Prisms, Light-selves, Shading devices

Daylighting tubes

Hybrid Daylighting Systems

Hybrid Daylighting Systems

Hybrid Daylighting Systems

The amount of daylight entering the interior changes constantly, the transparency of shading devices must adopt to this:

• dark exterior (night)

• adequate amount of daylight is present (eq. cloudy sky)

• intolerable amount of daylight is present (eq. clear sky)

Openings and Shading Devices

Openings - equipped with internal or external shading devices - must also ensure visual connection with the exterior, possibly at all times!

Openings and Shading Devices

Dark exteriorGlazed surfaces become “black holes” on the building envelope It is recommended to add “curtains” for the internal surfaces of the openings at night!

Shading devices

Shading devicesThe available amount of daylight constantly changes, the required amount of shading must be changed accordingly:

• manual control

• central - automated - control

The structure of the material of shading devices can be:

• homogeneous

Shading devices

Shading devices

The structure of the material of shading devices can be:

• inhomogeneous

Such materials might cause visual discomfort, glare in the interior!

Shading devices

The structure of the material of shading devices can be:

• inhomogeneousSuch materials might cause visual discomfort, glare in the interior!

Shading devices

The structure of the material of shading devices can be:

• homogeneous or

• inhomogeneousInhomogeneous materials might cause visual discomfort, glare in the interior!

Shading devices

The structure of the material of shading devices can be:

• homogeneous or

• inhomogeneousInhomogeneous materials might cause visual discomfort, glare in the interior!

Shading devices

The structure of the material of shading devices can be:

• homogeneous or

• inhomogeneousInhomogeneous materials might cause visual discomfort, glare in the interior!

Shading devices

The structure of the material of shading devices can be:

• homogeneous or

• inhomogeneousInhomogeneous materials might cause visual discomfort, glare in the interior!

Shading devices

The structure of the material of shading devices can be:

• homogeneous or

• inhomogeneousInhomogeneous materials might cause visual discomfort, glare in the interior!

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices

Color:it is recommended to use white or light gray colors to achieve maximal light reflectance

Light Diffusion:shiny materials ensure better light reflectance, but could also create glare (visual discomfort)it’s easier to clean the shiny surfaces

Shading devices