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Urbant klimat & U ba t at &klimatanpassad urban design
Erik JohanssonBoende och Bostadsutveckling
Urbant klimat & klimatanpassadUrbant klimat & klimatanpassad urban design
• Urbant klimatTemperatur– Temperatur
– VindE empel• Exempel
– Fez (Marocko)Colombo (Sri Lanka)– Colombo (Sri Lanka)
• Inverkan av urbana normer
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Global, regional and localgclimate phenomena
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Urban climate
Source: Boundary Layer Climates by T R Oke
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Urban microclimate
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Characteristics of the urbanCharacteristics of the urban climate
Mean air temperature 1-3°C warmer (occasionally up to 12°C)12 C)
Pollution 10-25% higher concentrations
Cloudiness 5-10% more
Solar radiation 5-25% lessSolar radiation 5-25% less
Mean wind speed 20–50% of rural wind speed
Turbulence 10–50% greater
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Värmeön (the Urban Heat Island)Värmeön (the Urban Heat Island)
S B d L Cli b T R Ok
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Source: Boundary Layer Climates by T R Oke
Värmeön (the Urban Heat Island)
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Source: Boundary Layer Climates by T R Oke
Temperaturvariationer för stadTemperaturvariationer för stadoch landsbygd
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Fuente: Boundary Layer Climates por T R Oke
Maximum heat island effect
• 3–5 hours after sunset3 5 hours after sunset• Calm weather
Cl dl ki• Cloudless skies
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Causes ofCauses of the urban heat island
Geometry of the built environment• Geometry of the built environment• Thermal properties of building materials• Heat from traffic, buildings etc• Lack of vegetationac o ege a o• Air pollution
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Radiation balance – dayy
UrbanUrban
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Radiation balance – night
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
H/W ratio – sky view factor
Sky View Factor (SVF) = cos
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Heat island as a function of H/W
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Source: Boundary Layer Climates by T R Oke
Surface material properties
Reflection Thermal capacity Reflection (MJ/m3°C)
Dry soil 0.4 1.3Dry soil 0.4 1.3
Humid soil 0.05 3.0Grass 0 15 0 25Grass 0.15-0.25 --Asphalt 0.05–0.20 1.9
Concrete 0.10–0.35 2.1
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Andra orsakertill värmeön
• Värme från trafik, b dbyggnader
• Brist på vegetation
• Luftföroreningar
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Effect of water bodies
• Large water bodies (seas, big lakes andLarge water bodies (seas, big lakes and rivers) may cause cooling through the sea breeze effectbreeze effect
• Smaller water bodies may cause cooling through evaporationthrough evaporation
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
P k h ö ådParker och grönområden• Lägre temperatur på grund av skuggning och
evapotranspirationevapotranspiration• Större parker kan vara 1–4ºC svalare än
i d b b lomgivande bebyggelse• Fler träd ger större
effekt• Parkens klimat på-p
verkar angränsande bebyggda områden
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-1821
ygg
Fördelar med vegetationFördelar med vegetationG k• Ger skugga
• Evapotranspiration medför temperatursänkning
• Absorberar regnvatten
• Vindskydd (viktigt under• Vindskydd (viktigt under kalla årstider)
Filt l ftfö i• Filtrerar luftföroreningar
• Biologisk mångfald
• Estetiskt tilltalande
• Motverkar stress
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-1822
• Motverkar stress
Effect of shading treesEffect of shading trees
• Protection againstgdirect solar radiation
• Less reflectedLess reflectedradiation
• Lower surface• Lower surfacetemperatures
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
P bl fPermeable surfaces
• Increased infiltration • Increased evaporation (cooling)
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-1827 jan-10 Erik Johansson, HDM 24
Wind in urban areas
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Wi d d tWind data
Urban winds 25-50% of rural wind speeds
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-1827 jan-10 Erik Johansson, HDM 26
Urban wind more turbulent
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Wi d i bWind in urban areas
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Source: Boundary Layer Climates by T R Oke
Wi d ff t f hi h i b ildiWind: effect of highrise buildings
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Source: Boundary Layer Climates by T R Oke
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Point Hyllie, Malmö (30 våningar)
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Scandinavian Tower, Hotell, VästraScandinavian Tower, Hyllie (17 våningar)
Hotell, Västra Hamnen, Malmö (85 m)(85 m)
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Exempel på problem iExempel på problem i kallt klimat• Vindproblem
id hö b d– vid höga byggnader– Raka gator
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Ways to reduce wind speeds nearWays to reduce wind speeds near high-rise buildings
Use of podium
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Increased wind speeds betweenIncreased wind speeds between buildings
funnel effectfunnel effect
High Higher HighestHigh Higher HighestHigh Higher HighestHigh Higher Highest
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Urban climate field studiesUrban climate field studies
Fez
Colombo
Fez, Morocco: Colombo, Sri Lanka: 1 4 illi i h b
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
1 million inhab. 1.4 million inhab.
M th dMethods
1. Microclimate measurements and calculation of thermal comfortcalculation of thermal comfort
2 Simulations of how urban design2. Simulations of how urban design influences microclimate and comfort
3. Analysis of urban regulations and interviews with urban planners andinterviews with urban planners and designers
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Climate measurementsClimate measurements in street canyonsy
• Air and surface temperaturesH idit• Humidity
• Wind speed
H
W
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
W
Calculation of outdoor thermalCalculation of outdoor thermal comfort
• Air temperatureh i l i ll • Mean radiant
temperaturePhysiologically Equivalent
• HumidityTemperature(PET)
• Wind
Assumed upper comfort limit: PET = 33°C
Assumed lower comfort limit: PET = 18°C
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Climate of Fez, ,Morocco
40
Temp. (°C)
Max. temp. Min. temp
30
20
10
Relative humidity: 40 – 70%
0J F M A M J J A S O N D
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
40 70%Month
M t it FMeasurement sites Fez
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Plot coverage of thePlot coverage of the neighbourhoods
Compact, traditional Dispersed, modern (deep canyon) (shallow canyon)
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Measured air temperature inMeasured air temperature in Fez – Summer
36
38°C
Old city Height/Width ratio:
32
34 New city
Rural
Height/Width ratio:
Old city 10
26
28
30
22
24 New City 0.6
16
18
20
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
1600:00 06:00 12:00 18:00 24:00
Measured air temperature inMeasured air temperature in Fez – Winter
Height/Width ratio:18°C Height/Width ratio:
Old city 1016
18
Old city
New city
12
14 Rural
New City 0.6 8
10
4
6
00 00 03 00 06 00 09 00 12 00 15 00 18 00 21 00 24 00
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 24:00
PET fysiologiskt ekvivalentaPET – fysiologiskt ekvivalentatemperaturen
• PET inkluderar kyleffekt från vinden och värmetillskott från solstrålningvärmetillskott från solstrålning.
T S lfö håll d Vi dfö håll d PETTemp. Solförhållanden Vindförhållanden PET
20°C molnigt vindstilla 20°C20 C molnigt vindstilla 20 C
20°C soligt vindstilla 30°C
20°C molnigt blåsigt 10°C
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Comfort comparison –Summer (PET)
°C
45
50°C
Old city
40
New city
30
35
25
15
20
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
00:00 06:00 12:00 18:00 00:00
Comfort comparison – Winterp(PET)
°C25
Deep
15
20Shallow
10
15
5
000:00 06:00 12:00 18:00 00:00
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
00:00 06:00 12:00 18:00 00:00
Conclusion from measurementsConclusion from measurements in Fez• Urban areas were found to be both
warmer (heat island) and cooler (cool island) than the rural surroundings
• There are big variations in thermal comfort within the city, both in summercomfort within the city, both in summer and winter
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Climate ofClimate of Colombo
40
Temp. (°C)
Temp. max Temp. min
30
40
20
30
10
Relative humidity: 75–90%0
J F M A M J J A S O N D
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
J F M A M J J A S O N DMonth
Measurement sites: Colombo
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Measured air38°C
DayMeasured air temperature, 34
36
38
p ,Colombo30
32
24
26
28
36
38°C
CBD - high rise
2407:00 10:00 13:00 16:00 19:00
Night32
34
36
Old city (dense)
30
32°C Night
26
28
30Centre - big avenue
Suburb (inland)
24
26
2824
07:0
010
:00
13:0
016
:00
19:0
0
Rural
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
20:00 23:00 02:00 05:00
Sea breeze
• Sunny afternoons
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18Erik Johansson, HDM 52
Results from measurements in Colombo
• Large climate variations within the city• Max. PET decreases with increasing
height-to-width (H/W) ratio of urban g ( )canyons
• Lower PET near the coast due to the sea-Lower PET near the coast due to the seabreeze
• Lower PET under colonnades and• Lower PET under colonnades and shading trees
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Results from interviews
• Climate is rarely considered in urban planning d d iand design
• Lack of knowledge about climate-conscious design
• Lack of tools and guidelinesg
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Current urban codes in Fez andCurrent urban codes in Fez and Colombo
• Introduced during the colonial timetime
• Based on principles from western countrieswestern countries
• low density to encourage solar access and fresh airsolar access and fresh air as well as daylight in buildingsbuildings
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
Lack of shadefor pedestriansfor pedestrians
• Wide streets• Low buildingsg• No shade trees,
arcades or otherarcades or other overhead shading
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
How to promote a climate-pconscious urban design
• Improvements of urban codes:– Allow higher H/W ratios– Allow ventilation around buildings (hot humid)– Prescriptions for shading
• Development of design guidelines• Training of urban planners/designers in
climate-conscious design• Development of design tools
Lund University / Dept. of Architecture & Built Environment / Housing Development & Management / 2012-01-18
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