Lecture_1_Daylight_in_Architecture_Source_and_Design_By_Yohannes.pptx

Lecture_1_Daylight_in_Architecture_Source_and_Design

1. Daylight in Architecture Lecture by- Yohannes Tsegay (Architect)

2. Daylight Light definition & Property of light Daylight Sources Daylight Components Daylight Strategies

3. Definition of Daylight

4. Light definition Light is the soul of architecture design. Light allow us to see, to know where we are and what around us. Light quality affects human behavior, health, comfort and mood. “Space, light and order. Those are the things that men need just as much as they need bread or a place to sleep.” Le Corbusier

5. Light definition… Light, space and human they effect and work with each other. Space needs light to illuminate; light needs space to receive it, light within the space changes human experience. Light work with some element like colors , can make space more dynamic and beautifier and it is a major natural element in design.

6. Light definition…

7. Property of light Intensity (Brightness) Frequency (Wave Length) Polarization (Direction of Wave Fluctuation) Speed of light The speed of light depends on the medium in which it is travelling. 299,792.458 m/s ≈ 3*10 6 m/s

8. Dayligh t Source The primary source of light for daylighting is the sun. The light received by the earth from the sun consists of two parts: Direct solar illumination Design Methods For the purpose of the daylighting design, direct solar illumination shall not be considered and only skylight shall be taken as a contributing factor to the illuminance of the building interiors during the day.

9. Advantage of Daylight The overall objective of daylight is to minimize the amount of artificial light and reduce electricity cost, but can also lower HVAC costs as well. The overall energy savings range from 15 – 40%. Reduce cooling loads by 10 – 20% Improve lighting conditions Color rendition, temperature and Sparkles.

10. Drawback of Daylight Increase heat gains. A high performance daylighting system may initially require a significant investment. Direct glare from sunlight may occur. Some architectural features, such as a building’s roof, atrium shapes can prevent daylight from illuminating a space.

11. Daylight Components

12. Three components of Daylight Design Aesthetics (Light and shadow, color, view…) Human performance (psychology and biology benefits) Energy (sustainable design)

13. Components of Natural Light There are three separate components of natural light that reaches any point inside a building. Sky component (SC) External reflected component (ERC) Internally Reflected Component (IRC)

14. Components of Natural Light 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%

15. Components of Natural Light 2. Externally Reflected Component (ERC) – reflected off the ground, trees or other buildings. ERC is small. The illuminance of ob. Is 10 – 20% that of the sky. 3. Internally Reflected Component (IRC) – the inter-reflection of 1 and 2 off surfaces within the room. IRC is half of the SC and is there for significant.

16. DF = ( Ei / Eo ) x 100% - FOR CLOUD SKY Where DF- Daylight Factor, Ei – interior illuminance & Eo - outside illuminance Components of Natural Light Daylight factor defined as: the ratio of daylighting illumination a horizontal point indoors to the horizontal illumination outdoors, expressed as a percentage. DF=SC+ERC+IRC – FOR CLEAR SKY Where SC- Sky Component, IRC – Internally Reflected Component & ERC – Externally Reflected Component

17. Daylight Strategies

18. Key Architectural Issues The DF in a particular building space depends upon a number of design factors including Size of daylight apertures (windows, skylights, etc..), Location of daylight (side lighting, top lighting, etc …), Access to daylight (Considering the site, building and room contexts), Room Geometry (height, width and depth), Reflectance's of room surfaces and contents, Reflectance’s of exterior surfaces affecting daylight entering the aperture………

19. Orientation of a building The orientation of a building is very important to achieve maximum daylight. 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. A North - South façade is better as it allows penetration of good daylight by avoiding glare and over heating. Architects should design based on the above.

20. Daylight Systems: How redirect the daylight into spaces? Windows Skylight Saw-tooth Clerestory Atria Light Pipes

21. Vertical Windows Useful daylighting will only reach a distance of 2.5 times to the height of the window from the floor. In a standard office building with a window height of 2.5 m, this means a maximum of about 5-7 meters.

22. Windows ... Window design in examples

23. Windows ... In overcast sky condition: Long thin horizontal windows will not provide as much light per unit area as taller more vertical windows. A) Is for three tall windows B) Is for one long, high level window.

24. Windows ... Light path from exterior to interior space.

25. Windows ... Light shelves – a light shelf is a horizontal surface that reflects daylight deep into a building. Light shelves are placed above eye-level and have high reflectance upper surfaces, which reflects daylight onto the ceiling and deeper into the space.

26. Windows ... Light shelves are typically used in high-rise and low-rise office buildings, as well as institutional buildings. This design is generally used on the equator- facing side of the building, which is where maximum sunlight is found, and as a result is most effective.

27. Windows ...

28. Windows ...

29. Windows ...

30. Daylight Strategies in different surfaces / roof

31. Skylight Skylight is a window set in a roof or ceiling at the same angle. Double glazed units and a range of louvered systems should be used wherever possible to reduce conducted heat losses. Appropriate no. of unit is 5% of ceiling area.

32. Skylight Skylight type can be different depending on the roof design and the interior space that are the major design factor.

33. Skylight Skylight placement as a function of building height.

34. Sawtooth They are apertures with vertical or angled glazing installed in a slopped roof plane. Sawtooth’s are most effective when used in series of three and were historically used in industrial and manufacturing buildings as the primary source of light source. Sawtooth slope is generally at a 45 degree angle.

35. Clerestory They are high windows with sill heights grater than 2.1 meter and excellent strategies for task illumination on horizontal and vertical surfaces. Glass higher on a wall generally provides deeper penetration into a room.

36. Clerestory Clerestory spacing as a function of a building height.

37. Atria They are central areas of a multi-storied building open to the sky. Atria can be glazed to create a controlled environment. Short and wide atria perform better than tall and narrow atria. Ex. Light wells, is dependent on aspect ratio.

38. Atria In order to use an atrium the farthest space should be far away in a minimum length of 2.5 x heigh of the building.

39. Atria Guggenheim Museum (Ceiling/Skylight) by Frank Lloyd Wright)

40. Atria Examples of Atria in different buildings.

41. Light Pipes One of the method which are simply tubular devices that are coated with reflective film that channel light from the roof of a building to the interior ceiling. There are also a number of mor experimental techniques being used in an attempt to direct light into buildings.

42. Light Pipes Different techniques to achieve the best light for interior space. Major 3 systems in light pipes Collector Transport system Emitter

43. Light Pipes It is more energy efficient than skylight since less energy escapes from the interior due to less surface area. DAY LIGHTING THROUGH LIGHT TUBES

44. Light Pipes Examples of light tubes in interior spaces.

45. The End Thank You!!!