How Urban Spaces Can Adapt to Different Climates

Urban Spaces: Climatic
By Dr Mohammad Hussaini bin Wahab

Introduction

Living (germs, plants,
animals, people, etc)
Environment : what surrounds a
thing or an item
Non-living (land, water, air,
wind, sun)
Human-made surroundings that provide the setting
for human activities ranging in scale from personal shelter and
building to neighborhood and cities that can often
include their supporting infrastructures such as water supply or
energy networks
BUILT ENVIRONMENT

1 | Greece Word –
“Klima”
2 | The weather conditions of any place: air
temperature, air humidity, rain etc
3 | Scientifically: Combination of physical natural
conditions of a place that become characteristic
of that place, over time
Climate

1 | The state of the atmosphere at a particular time and place.
4 | Temporary condition of the natural environment of any place
– changing and dynamic
2 | Weather is described in terms of variable conditions such as
temperature, humidity, wind velocity, precipitation, and
barometric pressure.
3 | Weather on Earth occurs primarily in the troposphere, or lower
atmosphere, and is driven by energy from the Sun and the rotation of
the Earth.
Weather

a) Tropical climate– hot and humid throughout the year
b) Mild climate– warm and humid
c) Dry climate – High temperature during summer and a huge
night and day temperature difference, dry throughout the year –
desert and steppe
d) Continental climate – cold and humid
e) Polar climate – Dominated by winter season. Need to
maintain internal temperature for comfort

Understanding Climate
Classification of Climate
 Cold climates
• The main problem is the lack of heat (under heating), or an excessive heat
dissipation for all or most parts of the year.
• Requires indoor heating all year round. The thermal insulation of buildings is
important for comfort and to reduce the amount of energy used for heating.
The potential for solar heating may be limited.
 Temperate climates
• There is a seasonal variation between under-heating and overheating, but
neither is very severe.
• Temperate climates have average temperatures ranging from 0–18°C for the
coldest, and 10–22°C for the hottest month.
• Requires both heating and cooling of buildings. This means that there is a
need for both thermal insulation and some thermal storage capacity (heavy
mass).
• Correctly placed windows can take advantage of the sun for heating.

 Hot-dry (arid) climates
• The main problem is overheating, but the air is dry, so the evaporative
cooling mechanism of the body is not restricted. There is usually a large
diurnal (day - night) temperature variation.
• Compact, heavy structures with small openings are common in this
climate. Some thermal insulation is advantageous, particularly of the roof,
which receives the most solar radiation.
 Warm-humid climates
• The overheating is not as great as in hot-dry areas, but it is aggravated
by very high humidities, restricting the evaporation potential. The diurnal
temperature variation is small.
• Shading and ventilation are the most important factors for comfort.
Buildings should be light with large openings and roof overhangs or
verandas.

BUT….
These climate types are only a very rough simplification. Monsoon winds,
created by temperature differences between the air over water and over land,
also affect the climate. These winds have the greatest importance in Asia and
East Africa. There are many variations and combinations, such as a mountain
or coastal desert climate. It is important to consider the seasonal variations in
any climate.
Even if the desert makes one think of unbearable heat, desert temperatures
can drop below freezing during winter nights.
The outdoor environment is also important. With correct design of the
buildings and the site, it is possible to create a microclimate in streets and
open areas that is significantly different from the surrounding “free” climate.
Topography and the proximity of plants and water play a large role. This is not
only important when people are outdoors – the buildings themselves stand in
this microclimate and interact with it.

Air temperature
• Air temperature is the intensity aspect of sun's
energy that strikes the earth's surface.
• Because the amount of energy from the sun
reaching the earth varies from day to day, from
season to season, and from latitude to latitude,
temperatures also vary.
• The earth as a whole receives a constant flow of
radiant short-wave energy from the sun. The earth
also radiates long-wave energy to space.
• During the day, the flow of short-wave radiation
absorbed exceeds long -wave energy emitted, and
the surface temperature increases.
• At no short-wave radiation strikes the darkened
side of the earth. But, long-wave energy is still
emitted from the surface. Therefore, surface
temperatures decrease

Air Humidity
• The amount of water vapor in the air
• The amount of water vapor that air can
contain is strongly dependent on the
temperature. The warmer the air is, the
more water vapor it can contain without it
condensing into droplets.
• Because of the temperature dependence of
the maximal relative humidity, air in the tropics
can take up much more water vapor than
air at the poles.
• Almost everywhere in the troposphere,
temperature decreases with altitude, and
therefore the largest possible concentration of
water vapor is higher near the Earth's
surface than higher up in the troposphere.

Factors that affecting site climate :
1 | Land Topography: slope ,orientation,
hills or valley
2 |Earth surface : manmade or natural,
ground temperature; affect the plants and
the climate
3 | 3-dimensional objects : fencing,
walls, building etc : Influence the wind
movement, shadow casting

Urban Climate
The factors that affect the urban climate :
- Changes of earth surface quality :
pavement, tar road (a lot of trees had been
chopped down creates many open hot
surface ) will increase the absorption of solar
radiation on the surface and decrease the
condensation process
- Buildings : create shadows and obstruction
of the wind movement; and absorb the heat
during the day and release it during the night.
- Energy seepage / heat release : through
walls, building air vent, refrigeration plant, air-
conditioning, industrial

Air pollution
Industrial activities, vehicles that
release smoke, dust and CO2 :
- Reduce the solar radiation to the
earth surface and blocking the
radiation to escape from the earth.
- Acid rain
-Solid particles create haze and
visibility distance become shorter
and accidents might happened.
- Ozone layer depletion – CFC,
deforestation

Air movement
- Obstructions like trees, buildings will reduce the
wind velocity
- But it will increase when flowing parallel
with the buildings or in between building
- The wind velocity will reduce up to 50%
when pass through horizontal obstructions
that have 10 times height
- The air temperature in the urban is 8⁰C
higher than rural area and the humidity is
less than 5% - 10% because of the high
temperature.

We cannot compete against climate,
we have to adapt….

Tropical Climate : Hot and Humid
 Example : Malaysia
 High humidity : 75 – 100%
 High temperature : 22 – 35 C
 Low temperature range between day and night
 Main problem: Heat (need to reduce heat received)
 Ventilation for cooling

- Need to allow ventilation, to get rid
of sweat and heat – loose garment
- Maximum protection over the sun

Example : Natural ventilation in a traditional
mosque

TRADITIONAL CHINESE SHOP-HOUSE
• Internal Courtyards
• Multiple Air-wells.

• High Ceiling
• Corridor /porch around building
TRADITIONAL COLONIAL HOUSE

- Bedouin Tent
1. Tensile Structure.
2. Portable, transformable
– nomad lifestyle – dismantled for camel ride within one hour
3. Animal leather (goat) – can withstand the solar radiation
4. The leather opacity is much better than a tent in white color in
controling the heat transfer
- Adobe Construction
– Mud brick adobe (16 – 30 inch thickness)
thermal Storage capacity to control the
temperature range between day and night
- Courtyard House
Saudi Arabia – compact and packed, self-shading
and minimal exposure to the sun.
Courtyard acts as lightwell and airshaft.
HOT AND DRY CLIMATE

- Igloo – very effective in terms of shape and
building materials
- Dome shape – give minimal surface area to
maintain the internal temperature and also
very earodynamic to refract the cold wind
- Igloo internal temperature can reach up to
20⁰C higher than the external temperature.
- The heat from lighting and occupant will
increase the internal temperature
COLD CLIMATE

Thermal Comfort

Definition
‘thermal comfort’ describes a
person’s psychological state of
mind and is usually referred to
in terms of whether someone is
feeling too hot or too cold.

Definition
Thermal comfort is very difficult to
define because you need to take into
account a range of environmental and
personal factors when deciding what
will make people feel comfortable.
These factors make up what is known
as the ‘human thermal environment’.

Definition
The best that you can realistically hope to achieve is a
thermal environment that satisfies the majority of
people in the workplace, or put more simply,
‘reasonable comfort’.
HSE (Health Survey England) considers 80% of
occupants as a reasonable limit for the minimum
number of people who should be thermally
comfortable in an environment.

Because thermal comfort is psychological,
it may affect our overall morale. Employee
complaints may increase, productivity may
fall and in some cases people may refuse to
work in a particular environment. Some
aspects of the thermal environment, such
as air temperature, radiant heat, humidity
and air movement, may also contribute to
the symptoms of sick building syndrome.

Deep Body Temperature
• Normal skin temperature is 37 °C
• If our body receive temperature :
40 °C = Heat Stroke
41 °C = Coma
43 °C = Death

Heat is continuously produced by the body. 20%
is used the remaining 80% needs to be
dissipated.
The human body loses heat to the environment
in three ways. Around the temperatures and
conditions associated with comfort, the
proportional contribution of each avenue of heat
loss is:
 radiation,55 %;
 evaporation through skin and lungs,30%
 convection and conduction, 15%.

Cool Biz Clothing

According to Koenigsberger Theory, the comfort zone for Tropical Climate would
be 22⁰C and 27⁰C with wind velocity of 0.15m/s to 1.5m/s

Ventilation

Ventilation
• The act of supplying fresh air and getting rid of foul air
1| Health
2| Comfort
3| Structural
cooling
Main purpose of ventilation
 Maintaining the air quality by having frequent
air changes
 Air changes in building is very necessary in all
type of climate
 Give thermal comfort by releasing heat from
human body
 Depriving the discomfort sticky and wet skin
condition
 Cooling down the building structure when the
internal temperature is lower then the external
temperature

1| HEALTH
FRESH AIR
 To supply oxygen for respiration
 To control smell
 To supply oxygen for human daily activities such as cooking
Water vapor /m3 air : 5-25gm/m3
AIR QUALITY

1 | HEALTH
AIR QUALITY
AIR AND RESPIRATION
Water vapour /m3 air : 45gm/m3
 During the respiration process, cough and sneeze will release
CO2 and water vapour
 The smoke from cigarettes will pollute the surrounding air and
damaging the human respiration system.

Different building require different rate of ventilation depending on
the purpose and function of the building.
There are 4 main categories :
a) RESIDENTIAL/COMMERCIAL
b) SCHOOL
c) HOSPITAL
d) TOILET
Residential/Commercial
Any spaces design for residential/commercial need to have openings
that allow for ventilation and lighting (10% from the total floor area and
5% can be opened)
MALAYSIA: UBBL (UNIFORM BUILDING BY-LAW)
PART III: SPACE, LIGHT AND VENTILATION
The architect has to comply the minimum ventilation rate requirement
stated in UBBL

School
Hospital
Any spaces used to accommodate patient need to have openings to
allow ventilation and lighting by the ratio of 15% from the total floor
area with 5% can be opened.
Classroom in schools need to have openings to allow ventilation and
lighting by the ratio of 20% from the total floor area with 20% can be
opened.
Malaysia: UBBL (Uniform Building By-Law)
PART III: SPACE, LIGHT AND VENTILATION
Toilet, WC, Urinal and Bathroom
Need to allow ventilation and lighting by the minimum ratio of 0.2sqm at
every openings.

 To achieve thermal comfort
Ventilation |THERMAL COMFORT
Depending on temperature and water vapour pressure at the building
surrounding
 Ventilation usually influenced by the air velocity, not the “air
supply” or “air exchange”
The relationship between flow rate and velocity depend on the space
geometrical and the position of the openings

a) Air has lower heat ability
b) If there is no ventilation, the air temperature can be equilibrium with the
external temperature
c) The temperature differences in the building depends on :
• Heat / temperature of building structure
• Thermal resistance
• External surface temperature rate
d) The air that flow into the building will mixed up together with the internal air
(heat exchange process)
Ventilation | STRUCTURAL COOLING

a) Heat exchange equation :
• Q =quantity of heat removed from or added to the indoor space in (K
cal /hr)
• V = ventilation rate in (m3/hr)
• 0.28 = volumetric heat capacity of air = 0.28 K cal/0C
• (ti – to) temperature differences between external and internal
temperature
Ventialtion STRUCTURAL COOLING
Q = 0.28 V ( ti – to )

AIR FLOW PRINCIPLES
It is important to understand 8 air flow principles before starting the
design process of a building.
Highpressure
Lowpressure
1st principle:
The air flow from higher pressure area to lower pressure

2nd principle :
Air has mass (momentum) and will be remained at the same
direction until being blocked by certain medium/obstruction

3rd principle :
The air velocity effects at the site is bigger when there are
obstructions such as trees or building which will caused the
changes of wind direction

4thprinciples
Big deflection of obstruction along the wind direction will
cause turbulent

5th principles
Bernoulli effects will reduce the pressure during the air flow on
the airplane wing surface and cause it to be lifted up

6th principles
Venturi effects will cause the air flow to accelerate when passing
through smaller opening
(plan)

7th principle
‘stack effect’ occur
when hot air in the
building being
pushed up to the
upper part of the
building by the cool
air infiltrated from the
outside of the
building because of
the different pressure
of air
Hot air been
released
Cool air
infiltrate
Heated up
(section)

8th principle
Outlet opening as well as inlet opening are needed in order to
encourage air ventilation inside the building
(plan)

AIR FLOW PRINCIPLES (SECTION)
The configuration of building, spaces and openings give a huge
influence to the ventilation in the building.
1st principle
Building design
raised on stilts allow
air to flow underneath
through open space
below the building
(Section)

2nd principle
Poor ventilation will occur when there is no continuity of
openings.
(section)

Window’s Placement Principles
The position of wind outlet will affects the air flow
• If the window located opposite with the wind direction, the air flow will
be effective
• Otherwise, the air flow will be less effective but can be improved by
positioning wing wall at a suitable place
Opening at opposite wall (plan A
& B)
Wing wall
Side by side opening (plan C &
D)

WIND WALL EFFECTS (After Chandra et al.,1983)
The wind wall position will affect the air flow
 Located at the opposite wall (A1, A2, B1 & B2 )
plan (A1) plan (B1)
+
+ +
+
plan (A2) plan (B2)
-
+ +
-

The wind wall position will effect the air flow
 Located side by side (C1, C2, D1 & D2)
plan (C1)
- -
plan (D1)
+ -
plan (C2)
+-
plan (D2)
+-
WIND WALL EFFFECTS (After Chandra et al.,1983)

The inlet outlet opening: same size
The opening on
the opposite wall
will allow
maximum air
flow. The
changes of air
velocity will
create cooling
effects at the
internal spaces
(After Bowen,
1981)
(plan)
L1 L1

The inlet outlet opening:
from bigger size to smaller size
Minimum wind
velocity will
occur when the
inlet opening is
bigger than the
outlet opening.
This condition
will create
cooling effects at
the external
area such as
patio (After
Bowen,1981)
(plan)
L1L2

Wind inlet outlet opening
: from smaller size to bigger size
Maximum wind
velocity will
occur when the
inlet opening is
smaller than the
outlet opening
which create
cooling effects
especially to the
building interior
(After Bowen,
1981)
(plan)
L1 L2

Wind inlet outlet opening : baffle
Either it is wing
wall, door etc
that been placed
blocking the
opening, it will
change the wind
flow direction in
small
amount(After
Bowen,1981)
(plan)
L1 L1

(section A)
Wind inlet outlet opening (in section)
The vertical position of the opening is very important in allowing
maximum air flow into the building. The best position is, to have lower
inlet position then the outlet. (After Bowen,1981). Section A-D showing
various vertical position of openings :-
t1
t2
t1
t2

(Section B)
Section A-D showing various vertical position of openings :-
t1
t1
t2t2

Section A-D showing various vertical position of openings :-
(Section C)
t1
t2
t1
t2

(Section D)
Outlet
Height
(SectionD1)
t1
t2
t1
t2

Outlet Height
(Section D2)
Wind velocity is
higher at the inlet
opening compare
to outlet opening
depends on the
size
(Evans, 1989,)

(Section B1)
There are two effects of having overhang in directing the air flow into
the building (After Bowen,1981).
Overhang application
t1t1
t2t2

(Section B2)
Overhang at higher level will act as windscoop to the internal spaces of
building. The opposite orientation encourage stack effect and increase
the wind velocity. (After Bowen,1981).
t1t1
t2t2
Overhang application

 In the hot and humid climate, people like to
send time lingering outside. This requires
these spaces to be shaded from the sun.
 In the arrangement of groups of building
requirement for ventilation and shade
contradict each other.
 Shades requires building to be huddled
together while ventilation requires it to be
placed far apart – spaced out

 The following illustration
demonstrate maximum
wind shadow area. As
such the wind only
blows along the outside
boundary and kept away
from the building.
 It gives ventilation only
for the first building at
the expense of
sacrifizing the other
buildings that lay behind
Building arrangement in regular rows will
create wind shadow between each bldg,
wind will be channeled into spaces
between them

 Staggered
arrangement will
gives bigger
spaces between
first row and the
building behind
Jarakmelebihi6kalitinggibgnutkmengelakkesanbayanganangin

 The following illustration
demonstrate that when wind
blows on the façade of the first
building it has sufficient area to
converge (bertumpu) to its original
direction before encountering the
consecutive (berturutan) façade.
 When the frontier is staggered
(susuk tenggiling) it allows more
building to have access to better
natural ventilation
 When wind flows around a
building is assess (membantu) the
availability of wind to the following
building, thus the distance
between building can be reduced
 This can be improved further by
angling the building into the wind

 As a conclusion, as ventilation is more
important in hot humid climate it seems
to be more logical to place building far
apart.
 To obtain uniform wind flow, “checker
board” arrangement is recommended
with staggered arrangements (not rigid
rows).

 The influence of high rise must be
analysed and must always remember
that when placing a low rise in wind
shadow area of high rise, it can cause
the wind to reflect and enter the building
in opposite direction.

 Wind blowing over an obstacle will produce
slower velocity in layers near the obstacle,
resulting in low pressure or suction zone.
 Low pressure in turn causes boundary layer
of air to return to its original position. The
time it takes to return is a function of the
small dimension of the obstacle. For 5-7mph
wind, the time it takes to return to original will
be greater. For slower air speed it will be
lesser.

Brunelli principle
 When air flows over
a curve surface it gift
a “lift effect”
 So if a roof is a
curve shape it will
be lifted if not fasten
properly

 Air flowing around a
curve will follow the
curve temporarily and
then separate
 The point where it
separates depends
on the air speed
 Air stream where it
separates will cause
“addies”
 Eddies will cause
occillation. This will
cause structures to
vibrate (bergetar)

 Tall buildings causes strong
down draught (tiupan bawah
yg kencang). This causes high
wind velocity at street level.
Air flow separates at 2/3
above the ground. Here 2/3 of
the air flows downward and
1/3 flows upward.
 A low building in front of the
high rise causes stronger wind
flow at street level
comparatively.
 If a building is set on pilottis it
will experience a jet effect
(high wind velocity)
1/3
2/3

 Rain will be driven to the
building façade
 Eddies at the back of the
building can cause smog
to be blown downward to
the back façade.
 Sheltered in wind shadow
area of the high rise

 The wind direction is in reverse of the
prevailing wind when blowing through the low
back building.
 The highrise has to be significantly tall so as
to create strong (-) pressure zone so as to
have wind flow in reverse. If this forward
building is of the same height no windflow in
the leeward building thus creating “heat
island”.

 The study conducted in Garston Research
Centre shows the effect of highrise in
mixed development.
 The separation of wind flow at the surface
of a row of building

Urban Heat Island

 A metropolitan area which is
significantly warmer than its
surrounding rural areas.
 The temperature difference
usually is larger at night than
during the day and larger in
winter than in summer, and
is most apparent when
winds are weak.
 The air in an urban heat
island can be as much as
11°C higher than rural areas
surrounding the city.

_ varies based on city’s structure
_ Parks, greenbelts reduce the temperature
_ CBD, downtown areas, residential areas are areas of warmer
temperature

Climatic domes
» Used to describe the “DOME” of air
over a city - the upper levels of the
urban heat island
» Contains more dust, more CO2, more
pollutants, less water
» Caused by - the man made surfaces
which store and re-radiate heat later in
the day
» Most extreme example - Atlanta
» In general a year round difference of a
minimum of 3 to 5 degrees is seen

 Use of heat-absorbing materials (e.g stone, metal,
concrete and asphalt) for building of roads,
sidewalks, parking lots and rooftops in cities.
 Stone-like cities only slowly loose heat at night
 Concrete & asphalt decreases the evaporation rate.
 From vehicles, industrial activity & air conditioning.
 Lack of vegetation and soil moisture.
 Geometric effects: tall buildings – blocking of winds &
canyon effects (surfaces for absorption of sunlight)
 Pollution changes the radioactive properties of the
atmosphere.

 Direct influence the health and welfare of
urban residents.
 Requires more energy for cooling purposes
=> increases emissions and electric
consumption
 Increases precipitation in cities and areas
downwind of cities.
 Enhances photochemical reactions, which
increases the particles in the air and thus
contributes to the formation of smog and
clouds.
 Culprit for global warming.
 Affects rain pattern in summertime.

Solutions
» Plant trees!
» Installing highly
reflective roofing
» Using less
asphalt for
pavements -
brighter surfaces
reflect heat
» Air quality
legislation

Solutions

GREEN BUILDING
Green Building practices promote construction of
buildings that are healthier for the occupants and
healthier for the environment.
Benefits of Green Building
 lower electric and water utility costs
 environmentally effective use of building materials
 enhanced health and productivity
 long-term economic returns
 reduced environmental impact

Benefits of GREEN ROOFS
• Natural Habitat for
Animals and Plants
• Stormwater Retention
• Urban Heat Island
Effect
• Visual enhancement

Greenery seems to be taking over the roof of one building in lower Manhattan.

GREEN ROOFS
Chinatrust Bank's headquarters, Taiwan.
• Designed to take
advantage of natural site
and climate features
• Designed to optimize
passive solar
opportunities
• Green roof gardens
reduce rainwater runoff
and urban heat island
effect
• Office tower facades will
feature intelligent
curtainwall technology,
• A combination of
sustainable design
features will reduce
energy consumption

CAR FREE CITIES
• Carfree Cities are population centers that rely
primarily on mass transit, walking, and/or biking
for transportation within the city.
• Carfree cities greatly reduce dependency on
petroleum, greenhouse emissions, automobile
accidents, air pollution, noise pollution, and
traffic congestion.
• Some cities have one or more districts where
motorized vehicles are restricted, referred to as
carfree zones, districts or areas

River Front Development

Many rivers flowing in big cities in the world are
currently covered under the artificial urban
environment such as concrete block pitching and
underground structures.
Recently, many cities in the world including Tokyo,
Paris, Seoul and San Francisco have begun
movements to uncover the rivers and to expose
them into the open air and sunshine.

Cheonggye Stream Project, SEOUL
Transforming into green

Cheonggye cheon Stream Project, SEOUL

Cheonggyecheon Stream Project, SEOUL

Cheonggye Stream Project, SEOUL
Urban Spaces: Climatic s

Consideration

Water bodies absorb much heat during
the day and reradiate it at night
1. Water Bodies

Water absorbs relatively large amount of radiation. They also allow evaporative
cooling. As a result, during the daytime areas around water bodies are generally
cooler. At night, however, water bodies release relatively large amounts of heat to the
surroundings. This heat can be used for warming purposes.
BUT….
Hot-dry climates
Water/ water bodies can be used both for evaporative cooling as well as minimizing
heat gain. Taking into account wind patterns and vegetation they can be used to
direct cool breeze into the house. A roof pond minimizes heat gain through the roof.
Cold climates
water bodies are beneficial only if their heat gain and loss can be controlled. This
would happen only if the water body can be enclosed by the building. However, we
may be faced with a large water body in a cold region. The best thing to do then is to
stay away from it. The wind pattern would have to be studied and winds avoided
either by building location, vegetation pattern or both.
Humid climates
Water bodies are best avoided. The minimal benefit provided by evaporative cooling
would be offset by the heightened humidity levels.

Absorptive surfaces and smaller open spaces
radiate less heat to buildings around
Greater the exposure of the walls and
ground to the sky, the more the heat loss.
Compact planning in the modern context:
Large heat production of modern buildings
makes compact planning inappropriate in hot
regions due to the decrease in heat loss
capacity.
Compact planning in cold climates: while
heat gain is reduced by compact planning,
the decrease in heat loss is significant.
2. Open Spaces and Built Form

Open spaces have to be seen in conjunction with built form. Together they can
allow for freer air movement and increased heat loss or gain. The lack of open
spaces could reduce heat loss or gain. Thus they can make hot, cold or humid
conditions more bearable or more unbearable.
BUT….
Hot-dry climates
Compact planning with little or no open spaces would minimize heat gain as
well as heat loss. When heat production of the buildings is low, compact
planning minimizes heat gain and is desirable. This is how traditional
settlements were often planned.
Cold climates
Open spaces should be small. Surfaces could be hard and absorptive. Compact
planning is, of course, preferred. They should allow the south sun into buildings.
Humid climates buildings should preferably not be attached to one another.
Streets and the open spaces should be oriented with respect to wind patterns.
The open spaces and the funnel effect can be used to maximize airflow within
the complex.

Urban Spaces: ClimaticUrban Spaces: Climatic
3. Ground Character
Different ground materials reflect, store and absorb heat to different degrees

Depending on the ground surface, incident radiation can be absorbed, reflected
or stored and re-radiated later. In other words, radiative heat gain could either
be decreased, increased during the daytime or increased during the night time.
Depending on the climatic context this could be used to our advantage.
BUT….
Hot climates
Ground surfaces preferably should be green in order to minimize heat gain.
Where hard surfaces and paving are unavoidable they should be rough but not
very dark. This would make the ground less reflective but not highly absorptive.
Cold climates
Heat gain would be maximized by reflecting the heat or storing it. Ground
surfaces should preferably be paved dark but smooth. This would increase
absorbtivity and reflectivity.

Urban Spaces: ClimaticUrban Spaces: Climatic
4. Vegetation Patterns
Vegetation increasing, decreasing and directing
airflow
Vegetation causes pressure differences which
shifts the air path

Vegetation and trees in particular, very effectively shade and reduce heat gain. It also
causes pressure differences, thereby, increasing and decreasing air speed or directing
airflow. They can, therefore, direct air into a building or deflect it away.
BUT….
Hot-dry climates
Heat gain is to be minimized, trees can be used to cut off the east and west sun. Hot
breezes can be effectively cut off. Planting deciduous trees is very useful in hot dry
climates. They provide comforting shade in summer and shed their foliage in winters
allowing sun. Evergreen trees can be used in cold climates to cut off breezes.
However, they would also absorb solar radiation and, thereby, cool the place.
Cold climates
Evergreen trees can be used in cold climates to cut off breezes. However, they would
also absorb solar radiation and, thereby, cool the place.
Hot-humid climates
Vegetation can be employed to maximize airflow. However, if they are not planted
carefully they would end up reducing air speeds.

5. Street Widths and Orientation
Street widths in hot climates: narrow north-
south streets minimize eastern and western
radiation.
Arrangement of building blocks to maximize airflow.
Street widths in cold climates. Wide east-west streets
maximize the scope for south winter sun.
Other Parameters: Air movement

The amount of direct radiation received on the street (and to an extent, on the lower floors) is
determined by the street width. The orientation affects the time of the day when the radiation is
received. Modulating the street width and orientation can very effectively control solar radiation.
BUT….
Hot-dry climates
Small street width to building height ratio ensures narrow streets and , thereby, shading. In
particular, streets running north-south should be narrow. This would enable mutual shading from
the horizontal morning and evening sun. East-west streets are avoidable as they allow
uncomfortably low sun in the mornings and evenings. However, if unavoidable, they too should
be narrow. The exact orientation of streets can be determined by considering the solar geometry
in combination with building heights. This will enable us to orient the streets such that
comfortably low sun is shielded off by the buildings.
Cold climates
wide streets, especially the east-west streets allow buildings to receive the south sun. However,
the need here is not just to gain heat but also conserver that which is received. So settlements
should be compactly planned. North-south streets should be narrow. Low building heights are
preferred. This would enable heat gain from the roof to be maximized. However, heat loss also
has to be minimized. In warm-humid climates the primary need is for air movement. Streets,
should therefore, be oriented to utilize the natural wind patterns.

CONCLUSION:
Climate influences every aspects of human life and hence their design decision
Within cities urban spaces will also influence the climatic character of the place
Tropical climate
 Cross ventilation is welcomed - very important for cooling, hence urban
space design must consider air flow pattern
 Sun shading characteristic – narrow streets allows shading of the street
or other public spaces by buildings & trees
 Sun orientation – avoid heat (east & west orientation)
 Covered linkages welcomed
Temperate climate
 Limit wind flow
 Reduce shading effect
 Sun orientation very important – east & west facing (welcomed)
important for heat
Dry & Hot climate
 Wind and sun need protection from
 Enclosed space welcomed

REFERENCES:
1. Givoni, Barush (1998) Climate Considerations in Building and Urban
Design.
2. Evans, Martin (1980) Housing, Climate and Comfort. Architectural Press,
London.
3. Markus, T A and E N Morris (1980) Buildings, Climate and Energy.
Pitman, London.
4. BORCKE, CHRISTINA VON (2003), “Landscape and nature in the city”,
in Sustainable Urban Design: an environmental approach, Randall
Thomas, editor.
5. CARMONA M. , HEATH T. , TIESDELL S. (2003), “Public Places, Urban
Spaces: The Dimensions of Urban Design”, Architecture Press

THANK YOU FOR YOUR KIND ATTENTION

How Urban Spaces Can Adapt to Different Climates

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