city and wind
climate as an architectural instrument
Mareike Krautheim Ralf Pasel Sven Pfeiffer Joachim Schultz-Granberg
contentS 6 10
POSITION – Climate as an Architectural Instrument The invisible beaut y – Wind
14 18
Kees Christia anse: Wind Fritz Reusswig: Urban Winds of Change
Experiencing the invisible 26 SENSATION – Experiencing the Elements 32 ART – Wind, The Invisible Beauty 36 THE power of wind – The Importance of Wind in Dutch History 40 Dots, gusts and MOLECULES – A Technical Introduction and a Little More 46 mapping wind – Wind Roses 48 protection – Strategies of Shielding 52 What if ...? – Predictions on Wind 56 vulnerabilit y – Global Impact of Wind 58 my ths – A Metaphor for Life and Death 62 Urban CLIMATE – Impact of Cities on Climate 66 World map of AIR FLOW
METHODS and instruments 70 Wind effects – A Handful of Principles 80 MEASURING THE UNMEASURABLE – A Short History of Measuring Wind 88 Wind and cit y – Towards a Methodology 114 118 122 124
Hans-Arno Jantzen: Fluidmechanics & Urban Space Peter Mensinga: Designing a Comfortable Breeze Christophe BARLIEB: In the Nature of Flow Ot to KlemM: Let Air In, Let Air Out
Designing with wind 134 Masdar Cit y, Abu Dhabi 138 Xeritown, Dubai 142 Vill a el Salvador, Peru 144 Windscape Cit y, The Netherlands 148 Flowmorphology, Germany 152 Sensational Cit y, The Netherlands 156 Through & Beyond, Germany 158 Jätk äsa ari, Finland 162 Mangh, Pakistan 164 Badgir, Iran 166 Malquaf + Dur Qa’a, Egypt 168 Druk White LOTUS School, India 172 LyceÉ Charles de Gaulle, Syria 174 School Complex, Burkina Faso 176 Semiramis, Morocco 178 Space Block, Vietnam 182 Climate Campus, The Netherlands 186 Tjibaou Center, New Caledonia 190 AIrtree, Spain 192 Wind SCALES, Saudi Arabia 196 Interactive FaCade, China 200 Interior Gulf Stream, France 203 Author BIOGRAPHIES 204 ADDENDUM
POSITION
CLIMATE AS AN ARCHITECTURAL INSTRUMENT
Architecture is generally considered an opponent of climate, which represents both a physical and a psychological threat. Architecture is often referred to as protection against rain, heat and wind. An alternative view, however, shows the significance and importance of climate for architecture. Climate 'localises' architecture and makes it complex, multi-layered and unpredictable. The effects of climate change are clearly visible worldwide. Within architecture and related fields, the focus of the current debate on building sustainable and energy-efficient responses to climate change is shifting to an increasingly global competition in outstanding high-tech applications. Irrespective of the global race for energy saving, the demand for meaningful energy alternatives is increasing, and the solution lies in dealing with specific and regional conditions in an intelligent way. The availability of technological means to negotiate climatological effects has replaced the skills needed to design with the climate. Climate has been of major influence on architecture for centuries. Orientation, form and materials were, for a long time, the logical consequence of local conditions. This has generated the many different traditional styles of architecture, each with its own regional characteristics and resources. Good examples of these are the Badgirs in the Middle East, the Manghs in India and, closer to home, the different inclinations of roofs in the Alps. These are all intelligent architectural expressions, with architecture deployed to exploit particular local climatological aspects. That said, globalisation, urbanisation and technological advances have caused architecture to abandon the role played by climate as a form- defining instrument. These days climate is mainly seen as something we need to protect ourselves against. This is a premise that automatically rules out many opportunities to achieve a richer and more sustainable architecture. In City and Wind – Climate as an Architectural Instrument, climate is once again deployed as an architectural instrument, so as to arrive at a design in which climate and sensory experience can function freely again.
6
TORONTO
NEW YORK
LOS ANGELES
DALLAS
CASABLANCA
RIO DE JANEIRO
ROTTERDAM
ANTARTICA
[Fig. 1.] Local wind directions as generator for forms and typologies of buildings and cities.
DUBAI
TOKYO
PORT ELIZABETH
SYDNEY
Climate in architecture is enlisted not only for protection from severe weather and to reduce the need for energy but also to reduce the distance between people and their surroundings. In this way, climate can be seen, felt and experienced in architectural spaces. It stimulates peoples’ senses – the cooling effect of the wind, the warmth of the sun, the silence and coolness of the underground or the smell of algae at low tide. Sensory experiences typical of the outdoors are key to this idea. These experiences in particular are those that enable that make architecture to stimulate and surprise, as well as to become a source of unprecedented depth. City and Wind – Climate as an Architectural Instrument, therefore, is a call to see architecture not just as a means to protect us against the climate, but also as an instrument to bring us back to it. Mareike Krautheim, Ralf Pasel, Sven Pfeiffer, Joachim Schultz-Granberg
7
Introduction [Fig. 2.] Mitch Dobrowner, Arm of God, Galatia, Kansas 2009.
We can’t change the wind, but we can adjust the sails. ascribed to Aristotle
The invisible beauty
WIND – A WIDE FIELD FOR ARCHITECTS AND URBAN PLANNERS YET TO BE EXPLORED
In the globalised world, architecture in its physical appearance, but also in its climatic sense, has become increasingly generic over the last decades. Notably since the 1960s a growing number of buildings became typologically identical, irrespective of their geographical location. The same applies to cities. Whereas the majority of medieval cities followed regional and climate specific conditions, many of the so-called “new towns� generate their own (ir)rational lay-out. Rational principles like optimising an infrastructural network, or irrational designs that create an allegorical image of the city rather than spatially programmed entities, seem to have long superseded a contextual urbanism.
The rising awareness of climatological issues in design processes has the potential to yet again make architecture more site specific and give it back its regional relevancy. In the course of the last fifteen years, the debate on sustainable architecture and ecological urbanism has risen like a phoenix from the ashes, since architects and urban planners, together with administrative bodies and developers, face a new responsibility regarding the complexity of their conventional design and planning methods. Spatial production today is inevitably linked to climate issues. Traditional ways of city development correlate with environmental issues, such as the use of solar irradiation, natural ventilation and precipitation, the reduction of emissions (notably CO2 and particular matter), bringing down the ecological footprint, minimising the energy consumption (etc.), up to the point of introducing complex recycling processes. All this is leading to an increasing complexity in the design process and also to an augmenting responsibility of the planning profession as a whole. Interesting enough, the research carried out so far in this field has been broadly developed into two directions:
10
ACTIVE
al Applic
n ic
Te c h
ns
tions
Desi
od s
Condi
Climate Design
renewable energy heating cooling ventilation water usage
gn Meth
wind temperature solar radiation precipitation air quality
tio
PASSIVE
C li m a
Design Process
Senso ry Ex p e
form appearence orientation materialisation programme layout green areas integrating environment building underground
te
y Based
rg
CLIMATE e ELEMENTS Fossile E n
HARD FACTORS using climate
ppli c a
ation
solar thermal energy heat exchange Tech. A solar cells wind turbine concrete core temp. control geothermal energy fermentation plant cogeneration
r
i e nce
ventilation renewable energy heat accumulation capacity cooling and heating water reuse/conservation moisturise daylight and shading
climate oriented architecture interior comfort building form reduction of mechanical transport optimisation of structure, form and infrastrukture
INTEGRATED DESIGN PROCESS
conventional energy generation central heating air-conditioning warm water production mechanical ventilation
experience of space in relation to climate experience atmosphere, incidence of light wind, temperature, solar radiation, precipitation, air quality taste, smell, sight, touch, hearing
SOFT FACTORS experiencing climate
• the formulation of generic principles for entities like eco-cities, neighbourhoods, infrastructure and individual buildings1, and • case studies on specific topics related to environmental performance, such as material research, insulation performativity or building integrated PV.2 Both areas of research leave one focus point largely untouched: the design with climate elements – solar radiation, temperature, wind, precipitation – as such. This is a wide field for architects and urban planners yet to be explored! In research by design, integrating climatological parameters into the design process defines the interface between research and design – and consequently between research and (spatial) production. As mediators of innovative, climate adaptive design strategies, architects can play a predominant role in the future: as scientists we strive to comprehend the world; as designers we strive to improve it.
11
1. Nikky Fleurke, “Sustainable Urban Design Approaches An Overview,” in The New Urban Question – Urbanism beyond Neo-Liberalism, 469–477. The 4th International Conference of the International Forum on Urbanism, 2009. 2. Jian Ge et al., “Potential of Energy Conservation through Renovation of Existing Residential Buildings in China, The Case of Hangzhou City.” In The New Urban Question – Urbanism beyond Neo-Liberalism, 425–435. Amsterdam Delft: The 4th International Conference of the International Forum on Urbanism, 2009.
Designing with climate is a practice that has been central to many forms of vernacular architecture. Whether this concerns traditional houses in the Alps, wooden houses in Scandinavia, pole houses in Bangladesh or adobe houses in the Arabic world, climate elements have for a long time played a significant role in the choice of materials, construction, morphology and replicability. Often, these regional adaptations to the climate are integral to the building’s layout and construction.
Today the availability of technological means to negotiate climatological effects has replaced the skills needed to design with the climate. Naturally, there are strong interdependencies between the climatological parameters: sun, temperature, wind and precipitation. Whereas most of these parameters are clearly defined, predictable and therefore rather reliable to work with, wind as the fastest changing and most dynamic one, is the most difficult to understand, a fact that makes wind almost impossible to work with. In a design process, however, wind as a dynamic medium is a highly interesting phenomenon. On one side the limited scientific predictability makes it hard to anticipate it, on the other side, this “knowledge vacuum” offers an enormous potential and freedom to break new ground in developing new designs and innovative climatological strategies. Designing with climate in architecture is highly complex and sometimes a paradox endeavour. Next to functional issues, sensory aspects play an important role, too. Architecture has to meet both requirements: first, the full exploitation of the climatic conditions in a technical and practical sense within a building process – hard-factors – and, second, the integration of climate related emotional experiences and sensory qualities – soft-factors.
Designing with climate means striking a balance between technical issues [optimisation] and emotional experience [realisation], between hard-factors and soft-factors.
12
In order to increase the awareness of climatological aspects as an integrated and indispensable part of the architectural design process, this book aims both give inspiration on how to deal with wind and provide a selected overview over specific case studies. It contributes to augmenting the knowledge in the field of sustainability and suggests how climate can be applied in architectural practice.
The research integrates wind as a substantial climatological parameter into the architectural design process. It supports the development of innovative design strategies that go beyond the usual spatial-programmatic performances of urban development. While the issues explored in this volume enhance the awareness of a climatological relevancy in architecture, the proposed design strategies can be pre-assigned and applied to spatial planning frameworks at a communal and also at a European level. As well as professional architects, urban planners and students of the field, it addresses planning institutions, policy makers, administrative bodies and developers in order to bridge the gap between the disciplines of spatial design, climatology and aerodynamic engineering. In doing so, it brings research closer to architectural practice and simultaneously manifests an important contribution to the debate of research in architecture. Hence the book consists of three parts. The first section comprises a selection of social, cultural, mythological and phenomenological issues relating to wind. The second develops a methodology how wind can be implemented in an architectural and urban design process. And the third provides an overview of case studies from best practice wind projects to exceptional unbuilt wind concepts. The book is written from the perspective of architects that understand (research by) design as an experimental discipline. As the focus lies in particular on the interaction between wind, architecture and the city, it was part of the experiment to closely collaborate with urban designers, climatologists and aerodynamic engineers. It is only due to this trans-足 disciplinary approach that the design results of the research could be understood, assessed and applied to a broader context.
13
Dots, gusts and molecules
a technical introduction and a little more
[Fig. 44.] Molecular representation of air at different temperatures (top: Hot air, below: Cold air).
Wind is the movement of atmospheric gases caused by differences in atmospheric pressure. It is strongly influenced by the rotation of the earth and friction with the earth’s surface. The atmospheric pressure differs due to varying exposure to solar radiation around the globe. Air consist of a mixture of gases, mainly nitrogen and oxygen. In gases the molecules move rather freely and are not firmly bond onto each other. Temperature influences the molecular behaviour: at high temperatures the molecules move more quickly, with a longer mean free path, which results in fewer molecules per cubic metre compared to at low temperatures. Wind and weather are inextricably connected with pressure patterns. The near-surface air pressure is a measure of the “weight” of the air that exerts pressure on the earth's surface.
[Fig. 45.] Natural colour image of Super Typhoon Haiyan as it moved west toward the coast of the Philippines. The image was acquired at 1:25 p.m. local time (4:25 Universal Time) on November 7, 2013.
40
In a low pressure area (Low) the atmospheric pressure is lower than it’s surrounding. Air masses flow into the “Low” region, converge, and move upward. Areas of high pressure (anticyclones) are characterised by a higher near-surface atmospheric pressure than in the surrounding area. Air masses diverge and flow out to areas of lower pressure. Correspondingly, air masses subside in the centre of the High.
For every action there is always an equal and opposite reaction 1
[Fig. 46.] Weather chart of Europe, December 6, 2013. air rises and cools down
L
As the total mass of the earth’s atmosphere stays more or less the same, variations in air pressure have to be equalised. Balancing out atmospheric pressure differences produces wind: air flows from areas of high pressure at the earth’s surface towards areas of low pressure.
air subsides and heats up
H
[Fig. 47.] High- and a low-pressure area at the L H From a high-pressure northern hemisphere. N area air flows clockwise towards the area of low-pressure (wind); in an area of low pressure air spirals upwards counter-clockwise. S 1. 3rd law of Newton's laws of motion, Isaac Newton (1643–1727), English physicist and mathematician.
15° per hour
41
H
L
L
H
H
L
L
H
N
NS
High pressure areas are characterised by stable weather conditions and light winds. Unsettled weather conditions are the characteristics of low pressure areas, where the condensing water vapour in the ascending and cooling air causes the formation of clouds and eventually leads to precipitation.
[Fig. 48.] Above: Air-flow around a high- and a lowpressure area caused by the Coriolis force (at the northen and southern hemisphere). S
The highest reported wind gust on earth: 408 km/h 2
15° per hour
[Fig. 49.] Below: Effect of the Coriolis force on a moving object, causing a deflection. actual intended 15° per hour path path
actual intended path path
The velocity of wind is determined by differences in air pressure. The greater the gradient, the faster the air flows. The wind direction is subject to the position of the different pressure areas. It is influenced by friction with the earth’s surface and the Coriolis force. The Coriolis effect is based on the eastward rotation of the Earth (1,670 km/h at the equator) and causes a sideways deflection of moving objects.3 In the northern hemisphere this means that the air flowing from the core of a high presvelocity of wind sure50% area 75% is deflected towards a clockwise rotation. Correspondingly, 50% 75% 100% 50% 75% 100% 100% 100% the air flowing around a low pressure area is deflected towards a coun500 ter-clockwise rotation. 400
100%
300 100%
200 100
height [m] city core
500
94% 400
300
90
Height [m]
[Fig. 50.] Decrease of wind speed caused by the friction with different surface conditions at the example of Berlin.
98%
90
75
open land 95%
200
2. The highest reported wind speed on earth was during the passage of tropical cyclone Olivia on the 10th of April 1996, Barrow Island, Australia. The Australian Bureau Of Meteorology, “Tropical Cyclone Extremes.” 3. The Coriolis effect is an inertial force described by the 19th-century French engineer-mathematician Gustave- Gaspard de Coriolis in 1835.
61 51
100
91
77
86 75
56 0
0
5
10
0
5
10
0
5
10
Wind Speeds [m/s]
42
The global circulation patterns of winds are a world-wide system by which a substantial part of the thermal energy from the equatorial region is distributed towards the poles. At the equator the radiation angle of the sun is rather perpendicular to the earth’s surface, which leads to a higher amount of incoming solar energy per square metre compared to the polar regions. These differences in solar heating cause global circulation of air in the troposphere. This circulation is translated into three types of cells girdling the planet in each hemisphere: the Hadley cells, the Ferrel cells and the Polar cells. The Hadley cells4 are the largest circulation patterns and extend from the equator to around 30° latitude north and south. The trade winds blow in the direction of the equator where the warm and moist air rises in the Inter-Tropical-Convergence Zone (ITCZ). Weather conditions at this band are determined by heavy cloud formations, thunderstorms and torrential rain. As the air rises by convection only, there is not much horizontal air movement. This is why this zone is also called the doldrums. Air masses ascend, cool down, produce rain, and flow towards north and south at altitudes of several kilometres. The air circulation closes up in the Subtropical Belt of High Pressure where the dry air subsides and flows back at surface level to the ITCZ.
Equator region
[Fig. 51.] Influence of the solar radiation angle on the available amount of solar energy per m2.
[Fig. 52.] Global circulation pattern, showing the three cells girdling the planet at each hemisphere.
Polar Cell 60°N Ferrel Cell
Polar region
Polar Easterlies
30°N
Subpolar Low (L)
Hardley Cell
Westerlies
Sub (H ) tropic al Belt of High Pressure
Equator
NorthEast Trade Winds Inter -Tropica ) l-Convergence Zone (L
Hardley Cell
SouthEast Trade Winds Sub ) tropic e (H al Belt of High Pressur
30°S
Westerlies Subpolar Low (L)
Ferrel Cell
60°S 4. Named after George Hadley, (1685–1768), English physicist and meteorologist.
Polar Cell
43
protection
strategies of shielding
1.
2.
3.
4.
[Fig. 59.] Different stages of protection.
Wind unites several specific and sometimes even contradictory forces: while some seem to work against, others seem to promote life on earth. Over the course of the centuries some astonishing and surprising adaptations have taken place, emerging out of the necessity to protect against strong winds. To meet the enormous forces of wind there are different strategies being developed: giving way (elastic and enduring structures that bend with the air flow like bamboo); on, in contrast opposing (resisting the forces of wind with a steady and strong material). In defiance of those two approaches there are some plants that rely strongly on wind incorporating it into their life cycle. Several grasses, for example, but also some crops like maize and wheat reproduce by wind pollination. Doing so enabled them to profit from the evolutionary advantages of cross-fertilisation despite their low evolutionary stage. For centuries mankind has tried to cope with the different properties of wind and, if possible, to make use of the potential it offers. Nevertheless, great and dangerous storms continue to cause huge damages every year. Tropical cyclones with enormous wind speeds of up to 315Â km/h and wind gusts of 380Â km/h1 create storm surges of several metre as they make landfall and extreme rainfall: despite all precautionary measures they pose severe threat to life and have devastating consequences. While the only concern under extreme conditions is to survive unscathed, under normal conditions the great power of wind is an important source of energy and is being used to ventilate houses and urban agglomerations.
Our skin is the most immediate means of protecting our body against wind and climatic conditions.
1. Caused by the Haiyan Cyclone on the Philippines on 8.11.2013, Royal Netherlands Meteorological Institute.
The skin is the first layer that protects mankind from external influences like wind. Further protective layers of clothing help to fulfil the requirements that the particular geographical location and climatological situation demands.
48
Protection against wind is offered by built structures like shelters or barriers that enlarge and improve the Lebensraum (biotope) of species and reduce the impact of wind. Wind shields can be made of either wind- impermeable / wind-proof materials that block off the wind or from (semi-)permeable materials that allow a portion of the wind to pass through them and, by doing so, slow down its velocity. Semi-permeable filters have the advantage that they reduce wind speeds without causing strong turbulence, which might well have a negative impact. Traditionally filters such as avenues of trees or hedges are planted along fields to prevent erosion by wind (deflation)1 and beside ship canals to reduce contrary winds.
[Fig. 60.] Fabrics such as wool keep the warmth of the source and form an insulating layer thanks to pockets of air between the individual fibres, which hardly let wind pass.
Wind protection as a part of the landscape Over the past few years a main focus has been on the development of wind proof fabrics. In technical terms a fabric can only be considered truly wind proof if its air permeability is 5 l/m2 sec or less2. Light membranes were developed that unite both wind- and water-proof qualities with vapour permeability.
[Fig. 61.] Above: Parachute canopies are made of a light strong material that is almost impermeable to air. [Fig. 62.] Left: Traditional protection of vines from the constant wind in the La Geria region of Lanzarote.
1. The Global Assessment of Soil Degradation (GLASOD) found 42 million hectares or 4 % of the European territory to be affected by wind erosion, EUSOILS - European Soil Portal Home Page, “Wind Erosion.” 2. GORE-TEX® fabric has over 9 billion pores per square inch.
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In the Port of Rotterdam the important but narrow water way of the of Nieuwe Waterweg (Caland Canal) between the North Sea and the industrial Brittaniehaven needs shielding by a wind barrier. Rough winds made navigation difficult, especially for large car-carrying ships, which encountered severe problems. The Rozenburg Wind Wall was designed to slow down strong gusts of wind and at the same time leave the typical Dutch landscape unaltered. The architect Martin Strujis and artist Frans de Wit designed a wind barrier that meets the requirements of letting only 25 % of the wind pass. The wind wall extends for 1.75 km and covers the particularly wind- susceptible stretches of the passageway with three different types of slabs.
The beauty of engineering: Wind barriers between land art and high tech. In the southern part of the canal where ships have to manoeuvre to and away from the quays have been placed the largest slabs, semi-circles about 18 m wide and 25 m high. At the Caland Bridge maximum wind protection is achieved by placing narrower semi-circle slabs (still 25 m high but only 4 m wide) close together. In the northern part of the canal the wind wall ends in a stretch of square-shaped slabs.
[Fig. 63.] Rozenburg Windwall of concrete slabs at the Port of Rotterdam, The Netherlands.
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In extreme Arctic and subarctic zones wind protection becomes a particularly important issue in architecture and urban planning. The architect Ralph Erskine has attempted to transfer the comforting and sheltered qualities of houses to open space. A street consisting of houses, trees, hedges and fences offers better protection than an open field. Groups of buildings or objects provide shelter from the wind. Buildings protect the inhabitants from climatic influences. Can buildings or clusters of buildings also be used to protect the surrounding open space? [Fig. 64.] Detail Ormen Långe by Ralph Erskine.
Erskine attempts to combine wind barriers and housing – the clothes of neighbourhoods. Erskine’s 1963 competition entry for Svappavaara, Sweden is not only a summing up of Arctic architectural studies but also a typical example of his own growing idealism during the early 1960s. The urban layout Erskine designed for Ormen Långe consists of a protective wall-building that encloses smaller neighbourhoods and allows both collective and individualistic ways of living. The public spaces were located along an indoor street at ground level and included such facilities as children’s playrooms and laundries. This inner street was meant as a sunlit meeting place with gathering places at either end, and it was also to be linked via roofed ways with schools, shops, bus stations and a health centre. The wind simulation illustrates the way the wall-building shelters the immediate neighbourhood of smaller houses, that have also been designed in such a way that they create small protected open spaces. On the whole it is fair to say that the living areas are protected but the huge open spaces between the different neighbourhoods remain rather unprotected.
[Fig. 65.] Ormen Långe, site plan of the wind protected neighbourhoods surrounded by the wall building.
[Fig. 66.] Wind simulation showing wind protected areas inside the development, causing a pattern of wind protected pathways.
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World map of air flow
Global impact of Wind
NJÖDR
ARICTIC ZONE
VOLCANO DUST EYJAFJALLAJÖKULL 20 MARCH 2010
SUBARCTIC ZONE MILD TEMPERATURE ZONE
STIBOG
SUBTROPICAL ZONE
FUKUSHIMA IMPACT
NEW AMSTERDAM AUG 31 AUG 30
TROPICAL ZONE
A
KATRINA
VOC TRADING ROUTES
SAHARAN DUST FERTILIZES AMAZON RAINFOREST
AUG 29 AUG 28 AUG 27
TROPICAL CYCLONES
HURRICANES AUG 26
HURRICANES CURACAO QUETZALCOATL
SURINAME
LOANGO SAHARAN DUST FERTILIZES AMAZON RAINFOREST RECIFE
HURRICANE CATARINA
1st RECORDED HURRICAN IN SOUTH AMERICA
TROPICAL ZONE
WIC TRADING ROUTES
LUANDA
CAPE TOWN
SUBTROPICAL ZONE MILD TEMPERATURE ZONE ARICTIC ZONE
66
TSCHERNOBYL TSCHERNOBYL IMPACT IMPACT 26 APRIL 26 APRIL 1986 1986
Dutch Trading Routes during Golden Age
FUJINFUJIN
FUKUSHIMA FUKUSHIMA IMPACT IMPACT 11 MARCH 11 MARCH 2011 2011
AEOLUS AEOLUS
Prevailing Winds
PAZUZU PAZUZU
DESHIMA DESHIMA FEI-LIAN FEI-LIAN
FORMOSA FORMOSA 09/18Z 09/18Z SETHSETH
TYPHOONS TYPHOONS
EN-LIL EN-LIL
CYCLONES CYCLONES DJIBOUTI DJIBOUTI
Tropical Cyclones
08/18Z 08/18Z 07/18Z 07/18Z 06/18Z 06/18Z
CEYLON CEYLON MALAKKA MALAKKA
Intensity Tropical Cyclones
HAYAN HAYAN 06/06Z 06/06Z 05/18Z 05/18Z
04/18Z 04/18Z 05/06Z 05/06Z
Dust Clouds
AMBON AMBON
CYCLONES CYCLONES
BATAVIA BATAVIA
CYCLONES CYCLONES
Intensity of Tropical Cyclones Tracks
TAWHIRI TAWHIRI
Nuclear Clouds
Wind gods
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Villa el salvador location
5+ 4-5
3-4
12.1째 S
urban project
m/s 22%
Lima, Peru project type
N
76 . 6 째 W
2-3
year
1-2
1971
0-1
urban design
Migual Romero Sotelo
N
climate
subtropical, dry
N 26%
26%
annual average temperature
19.2째C
annual precipitation
15 mm altitude
160 m sunshine
1447 hrs April
channelling effect channeling effect
evaporation on green
evaporation on water
September
Villa el Salvador is an urban district in the outskirts of Lima which arose out of housing shortage in the 1970s. Although it is a mainly deprived, simple and partly self-built area, here the orientation of the urban grid coincides with a steady prevailing wind from southwest. As air conditioning was not an affordable solution, the inhabitants were forced to draw on traditional opportunities. The strategy was to rely on natural ventilation in combination with evapotranspiration along adjacent green agricultural fields and green corridors. A steady sea breeze is cooled down and charged with humidity before it enters the urban fabric.
142
Cooling with green corridors Wide street profiles of about 50 m qualify the section for the channelling of wind. The urban fabric is penetrated; fresh air is able to circulate deep into the structure, improving the micro-climate and reduce the heat island effect. ›› pattern: 8 aligned buildings
[Fig. 180.] Exemplary site plan for a part of the development.
[Fig. 181.] Transversal section green corridor / street.
[Fig. 182.] Expected wind behaviour for a small sector.
143
Windscape City
9+ 8-9
6-8
51.9°N
urban study
m/s 14%
Rotterdam, Netherlands project type
N
4. 3° E
location
5-6
year
4-5
2011
3-4
design
1-3
Studio 51.9°N Franse, Zoet
0-1
N
climate
moderate, oceanic
N 18%
18%
annual average temperature
10.3°C
annual precipitation
825 mm altitude
4m
sunshine
1542 hrs June - August
wake interference flow
skimming effect
turbulent skyline effect
funnel effect
December - February
The wind conditions in Rotterdam are characterised by a moderate to fresh breeze from a prevailing southwest wind. Especially in winter easterly winds bring extremely low temperatures. Windscape City is a design scenario for the Maashaven docks that are part of the city-port of Rotterdam and located in the immediate vicinity of the expanding city centre. At the moment the site is a working harbour. With the upcoming completion of the new mega-port Maasvlakte II, the area will change its current use and will undergo an intense urban transformation.
144
[Fig. 183.] Top: Optimisation of the design process: There is a clear difference between the open “windy”parts and the dense “protected” areas, resulting from the ratio between the height and distance of the buildings. Wake interference flow and skimming flow principles apply.
[Fig. 184.] Left: A parametric pattern study reveals a gradual capability of controlling the wind speed. Dark areas with a reduced wind speed have a higher urban comfort, but less air circulation. [Fig. 185.] Bottom: The wind speed is gradually reduced by a varying ratio of buildings to open space.
145
[Fig. 186.] High and dense urban patterns divert wind over the site.
[Fig. 189.] Section.
[Fig. 187.] Ad-hoc pathways let the wind in and out.
[Fig. 188.] The diversified density of the urban pattern creates a varying intensity of the wind.
All buildings have the same volume but differ in height and ground coverage. This leads to an urban layout which presents a homogeneous density and continuously changing wind patterns, depending on the gradually varying porosity of the urban fabric. This project scenario plays with the different attributes of the prevalent wind in order to create specific wind related conditions within an urban fabric. In areas of low-rise buildings and higher ground coverage, the stepping effect applies and the wind is directed over the buildings. In areas with high-rise buildings and a low ground coverage, the funnelling effect is deployed. Through the variation in the urban topography, different wind conditions are present that allow a wide range of architectural possibilities regarding different programs and functions in the urban plan. The porosity of the urban layout is converted into the physical shape of the architecture too. The low-rise housing blocks are designed to optimise natural ventilation in the buildings by means of courtyards, patios and loggias, whereas the higher and thinner buildings that are predominantly programmed for public facilities and offices have an enhanced ventilation provided by the roughness of the facade.
146
Porosit y PoLicy With density-related parameters, the porosity of the urban fabric can be adjusted specifically. The tall buildings with a small ground-coverage give way to the wind, the lower buildings with a larger ground-Âcoverage force the heavy winds over the urban fabric, with slow winds between the buildings. ›› pattern: 9 porous buildings
[Fig. 190.] Openings in the facades positioned at different heights enhance turbulences and encourage interior ventilation.
[Fig. 191.] Schematic air flow.
147
Flowmorphology
8+ 7-8
6-7
51.9°N
urban study
m/s 18%
Münster, Germany project type
N
7.4°E
location
5-6
year
3-5
2011
2-3
design
1-2
Studio 51.9°N Holstein, Schiferli, Slot
0-1
N
climate
moderate, oceanic
N 16%
18% 16%
annual average temperature
9.4°C
annual precipitation
758 mm altitude
65.4 m sunshine
1593 hrs July
channelling effect channeling effect
diverting effect
funnel effect
wake interference flow
September - February
The proposal for the transformation of the city port area in Münster, Germany,investigates the relation of air flow, building geometry and aerodynamic effects on urban climate. Flowmorphology is a scenario that focuses on the interference between the urban fabric and wind. It provides a strategy to promote air circulation and the continuity of wind flow on all scales, the city, the street network and the building. In order to guarantee a continuous wind flow on all urban and architectural scales, parametric guidelines are developed that assure homogeneous wind conditions in a constantly changing city. Besides providing the fresh air supply and a continuous ventilation, the project aims to prevent flow disturbances in the city’s fabric.
148
[Fig. 192.] Aerial view.
Basic model: effect: turbulence result: disturbance in the airflow usage: slow down wind
Distorted model: effect: diverting result: acceleration usage: bypass
Curved model: effect: diverting result: turbulence reduction usage: canalise airflow
149