Dr. Niki Gaitani, Prof. Mattheos Santamouris Group of Buildings Environmental Studies Physics Department National & Kapodstrian University of Athens

1. INTEGRATED BIOCLIMATIC DESIGN AT URBAN SCALE
Dr. Niki Gaitani, Prof. Mattheos Santamouris
Group of Buildings Environmental Studies
Physics Department
National & Kapodstrian University of Athens

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Climate Change
Projections of extreme temperatures as represented by the combined number of hot summer (June-August)
days (Tmax>35C) & tropical nights (Tmin>20C)
Source: Fischer and Schär, 2010

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Key Observed & Projected Impacts from Climate Change for the main regions in Europe
Source: European Environment Agency (EEA), 2012c

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Potential Impact
IN GREECE:
A. Changes in annual mean temperature of
more than 3.5 degrees Celsius
B. The number of sunny days exhibit increases
of more than 40 days per year on average
C. Decrease in summer precipitation of up to
40%
Hot spots are mostly in the South of Europe
The annual number of days above 37C and 40C is increasing

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Heat waves
Source: The European Environment Agency, 2012. Heat waves - both a low share of green & blue urban areas &
high population densities contribute potentially to the urban heat island in cities

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Urban Heat Island
•City size & Urban Polulation
•Climate, Topography, Physical Layout
Modification by urban areas:
•Radiative
•Thermal
•Moisture
•Aerodynamic characteristics
http://www.ides-edu.eu/ Copyright 2014 IDES-EDU
Factors determining the strength of the UHI & its
impacts
Source: European Environment Agency (EEA), 2012c

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Urban Adaptation to Climate Change
Adaptation & Mitigation  the way towards a more
sustainable & resilient future for people & nature
Adaptation also relates strongly to using & expanding
green infrastructure such as parks, forests, wetlands,
green walls and roofs, wherever feasible &
sustainable  serves to provide a cooling effect on
cities as well as playing a role in managing floods
Support from a
national and European
framework is crucial in
assisting cities to adapt
Traditional
measures
Innovative
solutions
¾ of the population of Europe live in urban areas & this is
where climate change will be most apparent in everyday life

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Bioclimatic Design
Knowledge of prevailing climate conditions
Analysis & understanding of landscape data
Methods for applying this knowledge, through landscape design, to create
microclimate that are comfortable for people & minimize the energy use
of buildings

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Microclimatic Modifications
http://www.ides-edu.eu/ Copyright 2014 IDES-EDU

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Thermal Comfort
http://www.ides-edu.eu/
Copyright 2014 IDES-EDU

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Techniques to Mitigate Urban Heat Problems
1
•Reduce solar radiation using shading techniques
2
•Increase reflected radiation using light colors
3
•Use cool materials with high reflectivity and
emissivity
4
•Change inclination of surfaces
http://www.ides-edu.eu/ Copyright 2014 IDES-EDU

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Microclimatic Design
Parks & Green Spaces Permeable Surfaces
MaterialsTrees
http://www.ides-edu.eu/ Copyright 2014 IDES-EDU

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Adaptation Measures
cool cool
standard standard
25 30 35 40 45 50 55 60 65 70
(x 0.67 km)
10
15
20
25
30
35
40
45
50
(x0.67km)
ΔΤ(oC)
-3.0to-1.5
-1.5to0.0
0.0to0.5
0.5to1.0
1.0to1.5
1.5to2.0
2.0to2.5
2.5to3.0
“Cool” materials characterized by high reflectance to short wave radiation & high emissivity
to long wave radiation
The use of cool materials at city scale can contribute to the
reduction of air temperature

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Integrated Approach
A. Field measurements
microclimatic data (Tair,
Wind, Humidity, Tsurf)
B. Study the role of the
materials used in the
urban fabric (IR)
C. Investigation of
thermal comfort in
outdoor spaces
(Bioclimatic indices)
D. Integration of
microclimatic
information in the
design of open spaces
E. Evaluation of
proposed solutions with
bioclimatic CFD models

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Case study: Historic center of Tirana (1)

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Case study: Historic center of Tirana (2)
The use of passive cooling techniques involving cool materials,
solar control and additional vegetation as well as earth to air
heat exchangers can reduce the peak summer ambient
temperature up to 3 degrees, while surface temperatures are
decreased up to 6-8ºC
Bioclimatic design of open public spaces in the historic centre of Tirana,
Albania (2011) SUSTAINABLE CITIES & SOCIETY, 1 (1), pp. 54-62. Fintikakis,
N., Gaitani, N., Santamouris, M., Assimakopoulos, M., Assimakopoulos,
D.N., Fintikaki, M., Albanis, G., Papadimitriou, K., Chryssochoides, E.,
Katopodi, K., Doumas, P

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Case study: Marousi (1)
3rd Palenc, 5th EPIC & 1st Cool Roofs Conference, 29 Sept-1 Oct, 2010, Rhodes, Greece, Strategies for microclimatic modifications in the urban spaces-Marousi center, Greece, N. Gaitani,
A. Spanou, M. Saliari, M. Santamouris , F. Xyrafi

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Case study: Marousi (2)
3rd Palenc, 5th EPIC & 1st Cool Roofs Conference, 29 Sept-1 Oct, 2010, Rhodes, Greece, Strategies for microclimatic modifications in the urban spaces-Marousi center, Greece, N. Gaitani,
A. Spanou, M. Saliari, M. Santamouris , F. Xyrafi

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Challenges & Opportunities for Cities
•Local city characteristics tend to be highly important in terms of sensitivity to heat
•The results suggest that cities designed in such a way that makes them susceptible
to heat are not unique to one particular region
•It is highly likely that the length, frequency and/or intensity of heat waves will
increase
• Present day design of many cities with few green urban areas but many artificial
surfaces aggravates the impact of heat waves within cities, in particular by
increasing night-time temperatures
• City governments have a range of options at their disposal to be better prepared
for future heat conditions, including 'grey', 'green' and variety of 'soft' solutions

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Thank you!
Photos: Dimitris Messinis
ngaitani@phys.uoa.gr