Autodesk速 Ecotect速 Analysis 2011 3. Sustainable Sites and Green Urban Planning Emanuele Naboni MArch, PhD Building Science, LEED AP, EU licensed architect, Associate Professor in Climate Architecture / Royal Danish Academy Sustainable Design Consultant / www.e3lab.org email: emanuele.naboni@gmail.com
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速 Emanuele Naboni
Speaker: Emanuele Naboni Current - Associate Professor in Climate Architecture, Royal Danish Academy – Copenhagen 2005-09 Lawrence Berkeley National Laboratory (Researcher) 2007-09 Skidmore, Owings and Merril (Performative Design) 2006 LEED AP 2003-2006 PhD in Building Science, Politecnico di Milano & University of California 2002 Master in Architecture emanuele.naboni@gmail.com
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® Emanuele Naboni
Architectural design for a comfortable microclimate – the Earth The Earth's major source of heat and light, the sun, also creates the secondary climatic elements of wind and humidity that affect physiological comfort. These are caused by the configuration and nature of the local surface, such as the mountains, plains, oceans, deserts, and forests. The interplay between this astronomical source of energy with the effects it causes and the landscape creates the microclimate, which is the concern of the science of meteorology. Hassan Fathy
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Architectural design for a comfortable microclimate – the Built Environment However, the built environment produces changes in the microclimate. The configuration of buildings, their orientations, and their arrangement in space create a specific microclimate for each site. To this must be added the building materials, surface textures and colors of exposed surfaces of the buildings, and the design of open spaces, such as streets, courtyards, gardens, and squares. These man-made elements interact with the natural microclimate to determine the factors affecting comfort in the built environment: light, heat, wind, and humidity. Hassan Fathy
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Green Urban Planning Million+ cities today
336
cities worldwide with more than 1 million residents
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Green Urban Planning World’s 10 largest cities
Tokyo 35m Jakarta 22m New York 20m Seoul 20m Mumbai 19.5m São Paulo 19.2m Mexico City 18.5m Delhi 18m Osaka 17.3m Shanghai 16m
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Green Urban Planning Megalopolises
amalgamations of multiple cities into one
50m
population of the pearl river delta
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Green Urban Planning and Climate
From “Design with Climate”, Olgyay, 1963
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® Emanuele Naboni
Sustainable city A sustainable city, or eco-city is a city designed with consideration of environmental impact, inhabited by people dedicated to minimization of required inputs of energy, water and food, and waste output of heat, air pollution - CO2, and water pollution. Although the process of growing of the cities can’t be stopped the measures must be taken to minimize the energy consumption. Architecture and town planning must become instruments for creating harmony between cities and natural environment.
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Green Urban Planning water
environment
low carbon urgency
energy Form and fabric
materials
sustainability
daylighting Outdoor comfort Building perfomances
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Ecotect: Building Performance at Urban Scale §
Use shadows to protect building when needed to avoid overheating (Ecotect shadows calculations)
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Consider Energy Implications in Site Selection and Building Orientation (Ecotect calculated best orientation)
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Optimize building compactness (Ecotect thermal calculations)
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Orient building massing to be able to integrate passive and active solar strategies in buildings (Ecotect solar radiation studies)
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If renovating/retrofitting an existing structure (i.e. when employing passive solar strategies is not possible), consider planting trees to shade areas of the building that get more sunshine.
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Take advantage of natural ventilation and prevailing wind patterns, or protect form them depending on the climate (Ecotect Weather Tool)
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Maximize dayllight use. (Ecotect daylighting Analysis)
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Use reflected light to increase daylighing levels when needed (Radiance calculations)
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Investigate the potential impact of future adjacent developments to the site (e.g., solar and wind exposure, daylighting, ventilation, etc.).
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Ecotect: Outdoor Spaces Performances §
Control DIRECT SOLAR GAIN in the streets. (Ecotect shadows diagrams) This will mean calibrate street openings, shading or expose the streets
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Provide oravoid ventilation (Ecotect Weather Analysis Tool)
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Achieve daylighting by reflectance
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Balance material properties, thermal absorbtion and light reflectance (Ecotect Daylighting Analysis)
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Reduce Heat Islands Using Landscaping and Building Design Methods, use opposite strategies for cold climates(Ecotect absorbed radiation analysis)
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Maximize the use of existing trees and other vegetation to shade walkways, parking lots, and other open areas. (Ecotect absorbed radiation analysis)
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In hot-dry climates, compact planning with little or no open spaces would minimize heat gain This is how traditional settlements were often planned.
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Consider incorporating green roofs or photovoltaics into the project. (Ecotect PV modules calculations and absorbed radiation analysis)
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Sustainable Sites and Green Urban Planning Green Urban Planning with Ecotect Sustainable City Design Case Study: Royal Danish Academy Campus Pattern and Outdoor Space Performance Pattern and Building Performances The Solar Enevelope concept with Ecotect Urban Shading Right to Light Analysis Surface / Volume Ratio optimization Visisbility calculation Active Design and Photovoltaic Studies 1
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ÂŽ Emanuele Naboni
Royal Danish Academy Campus © 2008 Autodesk
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Royal Danish Academy Campus Š 2008 Autodesk
Royal Danish Academy Campus Š 2008 Autodesk
Cold Areas Bio-Climatic Urban Design §
The general RULES that govern Cold Climate Design are:
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create a sheltered MICROCLIMATE to make it LESS cold. If you design the site to capture the sun and buffer it from winter winds, it will make the local temperatures and conditions easier for the building to respond to.
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Maximize daylighting for both urban spaces and buildings
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Material should be choose as a balance between heat collection and light reflectivity
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ORIENT AND SITE THE BUILDING PROPERLY FOR THE SUN. If the buildings cannot receive free heat from the sun due to the orientation of its glazing away from the sun, then this will be a problem.
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maximize south facing facades for easier control. When we look at solar angles in the Passive Design powerpoint, you will see that south facing windows are preferable, both for the amount of free energy that they can provide, as well as the ease of shading them in the summer months when we wish to exclude unwanted heat from our building interiors.
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East and West facing windows are more difficult to control for solar issues. North facing windows do not benefit from solar gain, and result mostly in heating losses through the envelope.
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Solar Access
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Solar Access
Better solar access is possible with east-west street sections as the south face of the building will get sun for most of the day. Street spacing is adjusted so that the buildings do not block each other’s south light when the angles are lowest in the winter (for good design).
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Solar Access When working with street layouts that have a dominant north-south street orientation, during the morning and afternoon hours, particularly in the winter months, the street level and lower levels of opposing buildings are often in the shade. This is only alleviated by making very wide streets.
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North-south canyon effect at Bain Avenue Coop, Toronto
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® Emanuele Naboni
Acoma Pueblo, New Mexico, looking northeast. Terraces, windows and doors face southward to capture the winter sun. (Drawing by Gary S. Shigemura in Energy and Form by Ralph L. Knowles.)
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Solar envelopes (left) replaced by design (right) copyright: Ralph L. Knowles, 1999
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Solar Access – Right to light
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Solar Envelope
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Solar Envelope
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Solar Envelope’s right to light
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Solar Envelope replaced by design
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Shadows – winter optimum
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Shadows – winter optimum
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Solar Envelope butterfly diagram December 21st
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Shadows – December 21 – Shadows at 12:00 01 RD solar envelope-right to light analysis
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Shadows – December 21 – Butterfly Diagram 01 RD solar envelope-right to light analysis
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Shadowing, overshadowing and Sunlight Hours
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Shadowing, overshadowing and Sunlight Hours
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Shadowing, overshadowing and Sunlight Hours
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Comfort zone The Comfort Zone refers to the range of temperature conditions of air movement, humidity and exposure to direct sunlight, under which a moderately clothed human feels “comfortable”. This will be different for Indoor versus Outdoor conditions. These will be different for different CLIMATE types. Image from MIT – Maryline Anderson
As Architects we use our buildings to not only create comfortable indoor environments, but also pleasing and useful spaces outside of our buildings.
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Comfort Zone This famous illustration is taken from “Design with Climate”, by Victor Olgyay, published in 1963.
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Carbon Reduction: The Tier Approach
Image: Norbert Lechner, “Heating, Cooling, Lighting” © 2008 Autodesk
Reduce loads: Passive Strategies The tiered approach to reducing carbon for HEATING: Mechanical Heating Tier 3
Passive Solar Heating
Tier 2
Tier 1
Maximize Heat Retention
Maximize the amount of energy required for mechanical heating that comes from renewable sources. Source: Lechner. Heating, Cooling, Lighting.
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Reduce loads: Passive Strategies The tiered approach to reducing carbon for COOLING: Mechanical Cooling Tier 3
Passive Cooling
Tier 2
Heat Avoidance Tier 1 Maximize the amount of energy required for mechanical cooling that comes from renewable sources. Source: Lechner. Heating, Cooling, Lighting.
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Reduce loads: Daylighting The tiered approach to reducing carbon with DAYLIGHTING: Efficient artificial Lighting w/ sensors Tier 3
Glare, color, reflectivity and material concerns
Tier 2
Tier 1
Orientation and planning of building to allow light to reach maximum no. of spaces
Use energy efficient fixtures! Maximize the amount of energy/electricity required for artificial lighting that comes from renewable sources. Source: Lechner. Heating, Cooling, Lighting.
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Types Built up territories AspectofRatio: what’s best?
Different types of buildings an the same territory to build the same 75 tenements (“R. Rogers and partners” studio)
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Aspect Ratio: what’s best?
London City Hall, studies, Norman Foster Š 2008 Autodesk
Aspect Ratio: What is best in Copenhagen?
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Solar Envelope Consumptions S/V = 0.30
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Solar Envelope Consumptions S/V = 0.30
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Solar Envelope Consumptions S/V = 0.45
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Solar Envelope Consumptions S/V = 1.75
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Webgis Comune di Laives
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0
Micro-climate Whatever the FOUND condition of the site upon which we are to consider building has a climate that is not only dependent upon the general climate of the REGION, but also, the specific climate of the site as affected by: - the surface or surfaces that cover the ground - available tree cover, size, height, biodiversity, species, etc. - nearness to water - amount of paving adjacent - height of adjacent buildings
Institute of Contemporary Art, Boston
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ÂŽ Emanuele Naboni
Micro-climate When we design WITH the specific local environmental characteristics in mind, we start to manipulate the relationship between the climate, the site and the building to create a local environment or MICROCLIMATE around the building. This “mini climate” that is created around the building can decrease the apparent severity of the climate (and hence the work the building must do to make for a comfortable interior AND exterior environment around the building) OR, if badly handled, can increase the severity of the local climate. St. Thomas University, Houston
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Temperature Guidelines: Cold City: How to make a site Warmer? 1. Use maximum solar exposures 2. Provide for paved and masonry surfaces on south side of site. 3. Provide vegetational canopies to reduce night cooling. 4. Encourage “sun pockets” on site. 5. Make windbreaks with vegetation or fence like enclosures. 6. Remove shading devices during the day (or winter). 7. Use heat-retaining materials such as concrete or masonry. 8. Locate outdoor terraces for afternoon in the south or southwest.
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Temperature Guidelines: Warm City: How to make a site Cooler? 1. Make extensive use of shade trees as an overhead canopy. 2. Use vines, on trellis, or canopies on south and west facing walls. 3. Use trellises, overhangs -- this also limits heat loss at night. 4. Use ground covers or turf on earth rather than paving. 5. Prune lower branches of trees and reduce close shrubs to encourage air circulation. 6. Provide for evaporative cooling from water elements. 7. Use areas on north and east of building for outdoor activities. 8. Remove windbreaks which would limit airflow during warmer months.
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Humidity Guidelines: Dry Climate: How to make a site more humid? 1. Allow standing water to stay on site and limit drainage. 2. Encourage overhead planting which slows evaporation and provides moisture from the plants. 3. Add water elements such as fountains. Also helps from sound of water. 4. Use turf or ground cover instead of paving. 5. Use low windbreaks (below 1.2m) to preserve moisture transpired by surf or ground cover. 6. Use natural wood chip or peat mulch under all plantings.
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Humidity Guidelines: Humid Climate: How to make a site drier? 1. Maximize solar radiation exposure on site and reduce shading devices. 2. Maximize airflow and ventilation across the site. 3. Provide an efficient water drainage system for groundwater and storm drainage. 4. Pave all horizontal ground surfaces. 5. Reduce planting, especially ground covers and turf. 6. Eliminate all water bodies, pools and fountains.
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Incident Insulation Analysis - Whole Year
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Incident Insulation Analysis § The precise condition of the sky is taken into account when determining the amount of solar radiation that is received by a building. § The clearer the sky, the more energy received.
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Urban Heat Island
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Albedo "Albedo" or reflectivity is the ratio of the amount of light reflected from a material to the amount of light shone on the material. § In the case of pavements, a lower Albedo suggests that more sunlight in absorbed by the pavement. § This sunlight is converted into thermal energy and the pavement gets hotter. § Pavements with higher albedo collect less energy and are thus cooler. §
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Albedo Ranges
Albedo ranges of various surfaces typical to urban areas. [Sources: NASA, Akbari, and Thayer]
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Materiality and Site
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Microclimate and Site Materials Microclimate is the “mini climate zone” around your building as modified by local conditions. Things that naturally change your microclimate are: § amount of sun received over the day § wind and natural breezes § The natural materials of the site Things that YOU select also change the microclimate: § material choices: paving, roofing, wall materials and planting § colour of materials i.e.: In a cold climate select materials to: INCREASE HEAT in the WINTER DECREASE HEAT ABSORPTION in the SUMMER
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® Emanuele Naboni
Solar Radiation
[kWh/m2]
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Solar Radiation: Mapping Materials
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Incident Solar Radiation on Buildings
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Incident Solar Radiation
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Absorbed Radiation by Material - Summer
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Absorbed Radiation by Material - Summer
WITH GRASS
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ALL ASPHALT
Absorbed Radiation by Material – Winter
WITH GRASS
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ALL ASPHALT
Urban reflections
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Urban reflections § § §
§ §
URBAN REFLECTANCES of a space are governed by two primary surface characteristics of the building materials – COLOR AND TEXTURE. Color determines the quantity of light reflected by a surface. Dark-colored materials absorb light while light-color materials reflect light. Texture determines the quality of light leaving the surface after the reflection. Rough textured surfaces, referred to as matte, create diffused reflected light. Smooth or glossy surfaces create specular reflected light. When lighting a urban space, diffuse light is preferable because specular surfaces can lead to glare. A larger space has more opportunity for interreflections (losses) than a smaller space
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Reflectance of Materials
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Urban Daylighting: Reflectance
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External Reflection
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Private – Local - Global
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Daylighting Factor
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Daylighting Levels
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Internally Reflected
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Sky Component
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Reflectance Comparison
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Glare issue - Glass Envelope December 21st – 10:00
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Glare issue – Glass Envelope December 21st – 12:00
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Glare issue – Glass Envelope December 21st – 14:00
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Site Visibility
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Site Visibility
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Site Visibility
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Ecotect: Wind Flows in Copenhagen
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Wind Flows and Pressures Image from MIT – Maryline Anderson
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Form: ventilation §
the form of the building has a significant impact on the ability to ventilate a building using natural means
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natural ventilation is achieved by two mechanisms: wind driven pressure and stack effect when considering natural ventilation it is important to remember that the ventilation level is dependent upon wind speed and/or temperature and is therefore variable
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Wind Guidelines: Windy Climate: How to make a site less windy? 1. Use extensive windbreaks (plants, landforms, structures). 2. Use outdoor living areas that are semi-enclosed by building or landscape. 3. Do not prune or thin lower branches on tall trees. 4. Locate outdoor activities in areas protected by natural windbreaks. 5. Excavate and place activities partly below ground level in order to use the earth to block winds and require lower windbreaks.
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Wind Guidelines: How to increase wind flow and cooling? 1. Remove all obstructions to prevailing and predictable wind sources. 2. Use plants and landforms to funnel and accelerate breezes. 3. Prune all lower branches of taller trees. 4. Curtail and limit low plant growth between 1 and 10 feet high which would obstruct wind flow. 5. Locate outdoor activities in areas with maximum exposure to prevailing breezes. 6. Build decks or platforms in areas exposed to breezes. 7. Locate evening activities in cool air puddles or in sloped valleys to take advantage of airflow.
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Form: natural ventilation § § § §
in low energy buildings the form is often engineered to make best use of stack and/or wind driven ventilation shallow plan (low driving force resistance) atrium (high/low openings + high low pressure) ventilation chimney (high/low openings + high low pressure)
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Form: wind driven ventilation §
air flowing over a building gives rise to natural pressure differences low pressure
high pressure
§ §
low pressure
creates pressure difference across the building façade – this is the driving force for air flow judicious placement of ventilation opening creates a natural ventilation scheme
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Form: wind driven ventilation §
the available pressure difference between two surfaces of a façade is given by
1 2 ΔP = (c pa − c pb ) ρVf 2
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Form: stack ventilation § § §
this is driven by internal and external temperature differences occurs between openings at different heights as with wind pressure ventilation schemes the amount of ventilation is variable
& 1 1 # ΔP = − ρg 273h $ − ! % Text Tint "
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h
Ecotect: Photovoltaic collection optimization
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Royal Danish Academy Campus Photovoltaic © 2008 Autodesk
® Emanuele Naboni
Royal Danish Campus´ Roofs Ecotect Photovoltaic Potential PV crystal 250000000
10%
Wh
200000000 34%
PV Est
150000000
PV Sud 100000000
PV Ovest
50000000
PV Nord
44%
0 Jan Feb Mar Apr May Jun
Jul Aug Sep Oct Nov Dec
month
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12%
Royal Danish Campus’ Roofs Ecotect Shading Coefficients
100
%
80 60
Winter
40
Summer
20 0 PV Est
PV Sud
PV Ovest Roof
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PV Nord
KWh
Form and Photovoltaic Collection 350000 300000 250000 200000 150000 100000 50000 0 solar envelope
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court
court+green house
tower
Solar Envelope’s Roof Ecotect Shading Coefficients
100
%
80 60
Winter
40
Summer
20 0 PV Est
PV Sud
PV Ovest -
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PV Nord
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Emanuele Naboni
MArch, PhD Building Science, LEED AP, EU licensed architect, Associate Professor in Climate Architecture / Royal Danish Academy Autodesk Sustainable Design Consultant email: emanuele.naboni@gmail.com
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