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Daylighting slideshare

Daylighting for sustaianable Design Buildings

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Daylighting slideshare

  1. 1. Outline
  2. 2. Daylighting:  Source of heating and lighting.  Daylight enters a building via four primary mechanisms; Direct sunlight - Clear sky - Clouds (diffuse light) - Reflections from ground and nearby objects.  Daylight elements such as good lighting, window size and view out have a pivotal role in emotional satisfaction (Hourani and Hammad, 2012).  Crucial factor in determining sustainable architectural design and give a sense of pleasure in the architectural spaces. Figure 1
  3. 3. The Basic Principles of Effective Daylight Design  The orientation of buildings is important, if the length of the building is oriented in an east-west axis, it will allow penetration of passive heating or cooling within the building on a seasonal basis (Guzowski, 2000).  A north-south facade is better as it allows penetrating a good daylight by avoiding glare and overheating.  Designers could define which rooms need direct or indirect sunlight and require the quantity of heat or heat loss.
  4. 4.  Identifies the quality of daylight.  Different shapes, thin linear, L- shape, U-shape and doughnut need enough natural light through the courtyard and thin building  Courtyard and thin building, increase the nature light and heat distribution to the sides of building. Figure 2
  5. 5.  Glazing provides natural daylight but also allows unwanted summer solar gains and winter heat losses.  The larger the windows the more daylight and solar gain will enter - but the larger the heat losses will be.  Recommended glazing ratios are generally between 25- 50% of the external wall of the daylight space (Duxbury, 2013).  The optimum glazing ratio may vary due to individual factors such as orientation, location, obstructions (View of sky) and activity/user requirements.
  6. 6.  The type of glazing has a direct influence on thermal performance and daylight levels.  Triple glazing gives greater thermal comfort because its internal temperature is closer to the internal air conditions.  Triple glazing, tinted or reflective glass can result in reduced daylight levels.
  7. 7. Window specifications Daylight transmission Solar transmission = direct heat from the sun Single glazing 88% 83% Double glazing 77-80% 65-70% Double glazing - tinted 29% 39% Triple glazing 70% 40-60% Table1 shows Window Specification and Light Transmittance
  8. 8.  Windows should be high on the wall, widely distributed and of an optimum area to achieve adequate daylighting. Figure 4: show Light and shadow distribution produced by different windows positions, directions and sizes in a room. Figure 3
  9. 9.  Horizontal rooflights admit more daylight per square metre of glazed area than do vertical windows, a horizontal rooflight is proportionately three times more effective as a source of daylight than a vertical window. Roof Lighting: Skylights:  Skylights are domed, horizontal or slightly sloping glazed openings in the roof. Figure 5  Roof light areas should be limited to a maximum of 12% of the floor area to reduce excessive heat losses and gains.
  10. 10. Monitor Lighting  Monitor lighting can be used to reduce glare, heat gains, and protect internal spaces from direct sunlight, by providing an opaque roof and overhang above the glazing. Saw Tooth Lighting  Heat gains can be reduced by tilting roof lights towards the North in order to utilise diffuse north lighting. Figure 6 Figure 7
  11. 11. Clerestory Windows  Clerestory windows are usually situated at a high level (near the ceiling of the room) - always above eye level.  They provide an effective source of natural light and ventilation whilst reducing glare. Figure 8
  12. 12. Conclusion  In architectural design, natural daylight is a crucial component in determining sustainable building and the quality of an indoor environment.  Many significant factors determine the quality and quantity of daylight; site orientation, form of building and type, size, location of the glazing space.  The successful design of healthy building is controlling the natural lighting and distribute in spaces according to their needs.  Using appropriate glazing specification for buildings can result in reduce daylight levels and decrease in energy use for artificial lighting.
  13. 13.  DUXBURY, Liane (2013). Daylight and Modeling Case Studies (2013)  GUZOWSKI, Mary. (2000). Daylighting for sustainable design. New York, McGraw-Hill.  HOURANI, May, and HAMMAD, Rizeq (2012). Impact of daylight quality on architectural space dynamics: Case study: City Mall--Amman, Jordan. Renewable and Sustainable Energy Reviews, 16 (6), 3579-3585.  LECHNE, Norbert. (2009). Heating, cooling, lighting: sustainable design methods for architects. 3rd ed., Canada, John Wiley, Hoboken and NJ.  PHILLIPS, Derek. (2004). Daylighting: natural light in architecture. Oxford, Architectural Press.  SMITH, Peter F. (2005). Architecture in a climate of change: A guide to sustainable design. 2nd ed., Oxford, Architectural Press.  YAO, J. and ZHU, N. (2012). Evaluation of indoor thermal environmental, energy and daylighting performance of thermotropic windows. [online]. Building and Environment, 49, 283-29. Article from Science Direct last accessed 21 August 2013 at: http://www.sciencedirect.c. References