Transcript Climate and Architecture Geog310 Urban Climatology

Climate and Architecture
Geog310 Urban Climatology
Shelter with food, is one of mainstays of
human life on earth. The nature of shelter
required largely depends on the conditions
of the environment, with the climate
providing one base that determines the
type needed (in harmonic with
environment).
Climate Classifications
• Genetic classification: based on the
causes (air masses, atmospheric
circulation)
• Empirical classification: based on the
results (temperature and precipitation,
or vegetation patterns)
Generalized Climate Regions
Koppen’s Classification Categories
• Tropical (A): tropical wet (Af), tropical
Monsoon (Am), and tropical wet and dry (Aw
or Savanna).
• Mesothermal (C): humid subtropical (Cf),
Mediterranean (Cs), Mild humid subtropical
dry winter (Cw)
• Microthermal (D): humid continental and
subarctic
• Polar (E)
• Highland (H)
• Desert (B)
World Climate Classification
Climate and primitive constructions
1. In hot-wet tropics: latitudes 10°-15° from equator, mainly developing
countries, 40% population lives in the belt.
Small annual variation of temp, intense solar radiation, high humidity,
and heavy rainfall.
House should provide maximum ventilation and shades, roofs must
be waterproof, walls movable. House often stilted to prevent
frequent flooding near rivers that connect to outside world (or catch
sea breeze in island), movable shutters (or porous walls). Materials
have little or no heat storage capacity.
In tropical deserts (40°C daytime, and 10-15°C at night), intense solar
radiation and heat during the day and low temperatures at night.
Mud and straw are the basic materials. High heat capacity of these
materials help maintain even temp in the building; thick walls with
minimum window space. Grouped dwellings in dry area are often
built close together for maximum shade (narrow streets in many
Arab communities).
Valleys are parallel to prevailing winds (minimize wind exposure),
shaded side walk, short walking distance, courtyard with greenery,
compact geometry, use high albedo materials as building surfaces.
Dense and substantial thickness walls release heat during night,
block sun during day, indoor temp lag behind outdoor.
Polar region, Inuit Igloo: hemispheric shape minimizes hear
loss by providing maximum volume with a minimum of
surface area and effectively resists the strong Arctic wind
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Snow offers excellent insulating properties. Often several igloos are grouped closely
together and interior, protected passages connect one structure to another with only
one main entrance for that particular grouping of igloos.
The main entrance is protected by a snow wall that is perpendicular to the wind
direction and is usually oriented on the windward side of the structure, parallel to the
wind direction to avoid snow drifts found on the leeward of the structure.
The entrance on purposely lower than the surface of the snowpack and provides
access to a series of transitional spaces, called iglik. As one enters the igloo, through
the buried and curved tunnel, the floor rises until the iglik is reached through a low
bulkhead. The gradual rising floor elevation allows a pragmatic stratification of the air
mass within the igloo that collects the warmer indoor air within the iglik and confines
the cooler air to the natiq.
The hanging skins and the final low bulkhead, separating the main space, help
further to confine and tratify the air mass and block draughts from the exterior.
Outside Air is -50C, the top of dome can be as high as 15C, and close to zero in
natiq.
It is constructed of dry snow blocks that piled one on the other in an inward spiral,
snow has a low conductivity and help conserve interior temp. (59F or 15C). in
summer, they use turf, earth and driftwood to construct sod-roofed dugouts.
• A small window if ice that is curved from an available ice
pack and sealed within the hemispheric envelope facing
the sun. During summer, skins are hung on the interior
of the dome to create a relieving dark environment (long
daylight).
• Fig 17.6, Comparison of temp insides and outside of an
igloo (handout page 2).
• In Savanna (tropical wet and dry),
seasonal rains of varying intensities,
homes are dome or cone shaped to
facilitate drainage during wet spells,
constructed of grass, mud, branches,
animal skins (now replaced by cement
block types).
Mediterranean climate (dry in summer wet in
winter). Dual problem of seasonal climates.
Combination of arid regions with those of cool,
wet season.
Older dwellings in such region, ranging back to
Roman times, are identified by a central open
courtyard. These are shaded during the day, no
direct overhead in these latitudes. At night, they
are effective radiators, microclimate further
modified by fountains and pools in the
courtyards.
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Courtyard (figure 13.3b). perform cooling effect.
Keep daytime courtyard temp to a minimum by
shade and evaporation. Example, tall wide
canopy trees offer shade and provide thermal
transition zone insolating the courtyard climate
from the ambient air above it. However, it will
diminish radiation cooling at night. So build a
parapet on the buildings perimeter and sloping
the roofs inward to the courtyard. The periphery
parapet will reduce wind speed over the roof,
facilitate radiation heat loss and induce cooling
of the boundary-layer air next to the roof
surface, and allow cool air drain towards the
courtyard.
Water body: a fountain that sprays a fine mist
into a pool or sprinkling the large vegetative
canopy, or water sheeting down the surface of a
large wall. Psychological effect, make one feel
cooler.
Wind catcher or tower to harness the commonly
strong daytime wind. Openings at the top of the
tower are directed parallel to the wind, which is
funneled downward into the building and exits
across a pool of evaporating water. The effect
is an evaporative cooling process that
introduces cooler air into the building at the
lowest level and allows warm air to rise and exit
through a ventilation opening on the roof (stack
effect).
Climate and modern structures
• Construction of a home or business that uses its
background climatic environment as a resource
benefits in many ways: economic (decreased
energy costs), aesthetic (exhibited by landscape
design).
• Basic element: solar radiation.
Cold region welcomes direct solar radiation inside
house and on the walls;
hot climate avoid it.
• Two seasons, reduce ventilation and increase
insolation during winter, let in cooling breeze and
shield the insolation during summer.
How to calculate solar angle at give day of the year at a location?
• Solar altitude = 90 –
(latitude +/- declination
of sun (negative sign is
used when both in the
same hemisphere;
positive sign used if
they are on diff.
hemisphere).
• Ex, in winter solstice,
when sun is overhead
23.5S, the altitude of
the noon sun at 41N is
altitude=90(latitude+23.5)=90(41+23.5)=25.5
• In summer solstice,
overhead at 23.5N;
altitude=90-(4123.5)=72.5
Correct use of overhangs (climatology)
Example of house design in hot and arid climate
Fig 13.3, Applied Climat.
North/south oriented building-maximizing majority of wall surface of the structure facing
either east or west, the exposure to south or north is minimal, little wall to charge glaring
sun from south. Spacing between adjacent dwellings east-west of one another should
created mutual shading of the east-west wall to reduce intense morning and afternoon
solar radiation. Space should be 3 times the height of the buildings allowing sun to strike
east- and west-facing walls between 11:00and 13:00 hours
Solar protect of the walls at either end of the row of the adjacent dwelling can be
“shadowbelt” (for example, trees, for shading and noise and pollution barrier).
• Indoor
temperature has
smaller diurnal
variations
• The maximum
and minimum
temperature
occur later
indoor
Climate Zones
house design specific
for different climate
zones