View
218
Download
1
Tags:
Embed Size (px)
Citation preview
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20021
The Design of Ecological Buildings: Shading and Lighting
Professor Yan ChenProfessor Les Norford
Department of ArchitectureMIT
Traditional shading technology New shading technology
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20022
What not to do - Beijing housing: vegetation but not much shading
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20023
What not to do - Balconies are enclosed and no longer provide shading
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20024
What not to do – worst case
Which way is south? Where is the window shading?
Can occupants possibly be comfortable without air conditioning?
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20025
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20026
Climate Zones: Architecture
Boston Beijing
Ice Caps
Tundra
Mountain
Continental
Marine-West coastal
Mediterranean
Subtropical
Rain Forest
Savannas
Steppes
Deserts
40-42 N
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20027
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20028
Shading by Buildings - Italy
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
20029
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200210
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200211
Solar Shading
Villa Shodhan, Ahmadabad Unite Building, Marsailles, France
•Shading devices and roof gardens provide excellent shade and comfort for south facing walls
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200212
Window shading inMumbai, India
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200213
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200214
Even newer buildings have at least some window shading
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200215
A school in Gujarat, India – note the depth of the facade
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200216
Solar Shading
•Protective shading in Brazil. Adjustable louvers between fixed vertical concrete fins
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200217
Housing in Zimbabwe – another deep façade and a good use of pre-
cast concrete
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200218
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200219
How about a very different type of high-rise building for a hot and humid tropical climate?
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200220
Back to Beijing - vegetation helps reduce indoor temperatures
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200221
Vegetation and shading from overhanging surfaces – looks cool and comfortable
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200222
Awnings and plants
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200223
Detailed View of Shading # 1:Osuna Housing, Seville, Spain
Notice strong solar orientation of the buildings on the site.
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200224
Shading – relatively few windows on the west facade
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200225
Winter sun for daylighting and solar heat
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200226
Summer sun is blocked
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200227
Detailed Look at Shading #2: Solar Village 3 Athens, Greece
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200228
Align most buildings to face North-South
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200229
Site orientation
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200230
Shading system
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200231
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200232
Note depth of south facing façade
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200233
Shading Design
1. Determine when shading is needed
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200234
2. Determine elevation and azimuth of sun when shading is needed
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200235
3. Choose a shading device – fixed ….
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200236
… or movable
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200237
In hot climates, south-facing windows are best because they bring in the least heat
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200238
4. Determine size of shading device
Example: movable south-facing shading
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200239
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200240
Assessing lighting inside a Shanghai apartment
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200241
Use simulation to estimate indoor illuminance
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200242
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200243
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200244
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
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200245
Trading off cost of windows and insulation against energy use – results of an automated search
Beijing - Pareto front [First and last generations]
0
1000
2000
3000
4000
5000
6000
2 3 4 5 6 7 8 9 10 11 12
MWh
Co
st
($)
Gen 1
Gen 100
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200246
What’s best? Construction details
• The most expensive but most efficient construction uses:– Large south-facing and small north-facing
windows– Lots of insulation in both walls, but more in the
north-facing wall
• All of the optimal trade-offs use double-glazed windows
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200247
Repeat for east-west apartment
Beijing East/West case- Pareto front [1st and last generations]
0
1000
2000
3000
4000
5000
6000
7000
2 3 4 5 6 7 8 9 10 11
MWh
Co
st
($)
Gen 100
Gen 1
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200248
East-west apartment
• Higher energy use than an apartment facing north-south, as expected
• The most energy-efficient solution has windows of about 2 m2 in the east and west walls, compared to about 8 m2 in the south wall and 0.8 m2 in the north wall
The Design of Ecological Buildings – Lighting and ShadingInternational Seminar on Green Housing, Guangzhou, China, June
200249
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.