1. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 1 The Design of Ecological Buildings: Shading and Lighting Professor Yan Chen Professor Les Norford Department of Architecture MIT Traditional shading technology New shading technology

2. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 2 What not to do - Beijing housing: vegetation but not much shading

3. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 3 What not to do - Balconies are enclosed and no longer provide shading

4. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 4 What not to do – worst case Which way is south? Where is the window shading? Can occupants possibly be comfortable without air conditioning?

5. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 5 The Earth’s Comfort Zones Around the world people have developed energy- efficient building forms that are suited to the climate conditions of their particular location – a form of ‘solar vernacular’. They have developed simple solutions to the environmental challenges set before them: heat, cold, rain and wind. These solutions have been developed using a limited range of indigenous building materials, all of them renewable

6. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 6 Climate Zones: Architecture Boston Beijing Ice Caps Tundra Mountain Continental Marine-West coastal Mediterranean Subtropical Rain Forest Savannas Steppes Deserts 40-42 N

7. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 7 Mediterranean Climate Closest to the ideal climate - warm but dry with mild winters. People must protect themselves from the intense heat of summer and extreme light by shading and thermal mass. Life slows down in summer, as cooling is not always affordable. Arcades and verandahs create microclimates merging the bright outside with the cold dark indoors

8. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 8 Shading by Buildings - Italy

9. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 9 Marine West-coastal climate Not too hot, not too cold – the oceans have a calming influence on the temperature on land. The strong winds and rain that come with the cold winter make this a good environment for people to work in, as long as they have warmth and protection A balance is required between daylight and insulation – large windows allow natural lighting and ventilation. The low embodied energy of Georgian houses, using brick, wood and glass, has proved very sustainable for over 200 years

10. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 10 Subtropical Climate A pleasant climate for most of the year, but summers are humid so ventilation is a necessity. The Japanese and Chinese developed systems of dynamic walls to create buffer zones between inside and outside, providing more comfortable summer spaces. Houses in the southern US use the porch as a buffer zone. In Japan the sliding screens allow maximum cross ventilation. Chinese roundhouses contain a protected fully sustainable community

11. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 11 Solar Shading Villa Shodhan, AhmadabadUnite Building, Marsailles, France Shading devices and roof gardens provide excellent shade and comfort for south facing walls

12. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 12 Window shading in Mumbai, India

13. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 13

14. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 14 Even newer buildings have at least some window shading

15. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 15 A school in Gujarat, India – note the depth of the facade

16. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 16 Solar Shading Protective shading in Brazil. Adjustable louvers between fixed vertical concrete fins

17. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 17 Housing in Zimbabwe – another deep façade and a good use of pre- cast concrete

18. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 18 New facade technologies many new high rise buildings in Europe are experimenting using double skin wall technology- allowing natural ventilation and adjusting to summer and winter climate conditions

19. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 19 How about a very different type of high-rise building for a hot and humid tropical climate?

20. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 20 Back to Beijing - vegetation helps reduce indoor temperatures

21. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 21 Vegetation and shading from overhanging surfaces – looks cool and comfortable

22. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 22 Awnings and plants

23. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 23 Detailed View of Shading # 1: Osuna Housing, Seville, Spain Notice strong solar orientation of the buildings on the site.

24. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 24 Shading – relatively few windows on the west facade

25. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 25 Winter sun for daylighting and solar heat

26. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 26 Summer sun is blocked

27. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 27 Detailed Look at Shading #2: Solar Village 3 Athens, Greece

28. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 28 Align most buildings to face North- South

29. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 29 Site orientation

30. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 30 Shading system

31. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 31

32. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 32 Note depth of south facing façade

33. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 33 Shading Design 1. Determine when shading is needed

34. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 34 2. Determine elevation and azimuth of sun when shading is needed

35. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 35 3. Choose a shading device – fixed ….

36. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 36 … or movable

37. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 37 In hot climates, south- facing windows are best because they bring in the least heat

38. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 38 4. Determine size of shading device Example: movable south-facing shading

39. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 39 A word about lighting Relatively easy to do with houses because room sizes are small Still important –Reduces energy for lighting –May reduce energy for cooling –Meets human needs for sunlight and contact with nature

40. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 40 Assessing lighting inside a Shanghai apartment

41. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 41 Use simulation to estimate indoor illuminance

42. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 42 Developers and designers can get help from the research community Encourage and support research to find new ways of determining energy-efficient designs Conduct design competitions in which carefully documented estimates of energy use are a key part of submittals

43. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 43 A new technology: automatically trading off cost of windows and insulation against energy use Consider a Beijing apartment, with north and south exposures Vary window size, glazing type, and wall construction in each of the two walls Compute construction cost and operating energy Search for lowest operating energy for a given construction cost

44. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 44 Search procedure Use the DOE-2 energy calculation program to estimate yearly energy use for heating, cooling and lighting Use a genetic algorithm to automatically search for the best trade-offs between operating energy and construction cost

45. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 45 Trading off cost of windows and insulation against energy use – results of an automated search

46. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 46 What’s best? Construction details The most expensive but most efficient construction uses: –Large south-facing and small north-facing windows –Lots of insulation in both walls, but more in the north-facing wall All of the optimal trade-offs use double- glazed windows

47. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 47 Repeat for east-west apartment

48. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 48 East-west apartment Higher energy use than an apartment facing north-south, as expected The most energy-efficient solution has windows of about 2 m 2 in the east and west walls, compared to about 8 m 2 in the south wall and 0.8 m 2 in the north wall

49. The Design of Ecological Buildings – Lighting and Shading International Seminar on Green Housing, Guangzhou, China, June 2002 49 Conclusion Developers and designers can make buildings more comfortable and efficient, by setting high goals and working with government organizations and building scientists. Better control of sun and light need not be costly and can provide a distinctive and pleasing form to buildings as well as save energy for lighting and cooling. Researchers should be encouraged to generate new designs and to pin point trade-offs between energy use and cost.