Design in warm humid climate

1. Warm Humid Climate Design

2. Climatic conditions
• In tropical and subtropical regions the daytime temperature is uncomfortably
high, particularly during the warmer seasons and in low altitude locations.
• Air temperature remains moderately high, between 21 and 32°C
• Air humidity influences the precipitation pattern and the amount of solar
radiation that reaches the earth's surface.
• The influence of a cloud , invisible humidity in the atmosphere also alters the
amount of radiation, rendering it diffuse.
• Winds are generally of low speed, variable in speed, but almost
constant in direction
• These factors result in mean temperatures that differ highly from place to place.
• Annual and diurnal fluctuations also vary sharply.

3. Design objectives and response/Physiological objectives
• The main objective of climatic design is to provide comfortable living conditions with a minimum and
meaningful input of artificial energy.
• This also reduces investment and running costs as well as ecological damage.
• Increase heat dissipation from the body to its environment, at least as much as the metabolic heat
production of the body.
• Saturated air envelope can be removed by air movement across the body surface of the occupants.
• Radiant heat gain from the sun and sky should, however, be prevented.
•

4. Settlement Planning
Topography, to benefit from microclimatic variations. Sun-orientation
Settlements are preferably placed on northern slopes to avoid
excessive sun exposure, using natural shade.
Valley bottoms are additionally heated by reflection of sun
radiation from the surrounding slopes .
Elevated sites are preferable.
Locations at higher altitude have lower temperatures
due to the adiabatic phenomenon.
The mean temperature decreases by 1°C with 100-m
altitude difference.
Valleys tend to have lower wind velocity and hence the
cooling effect by wind is reduced.
Wind - orientation
Air pollution
An air trap may result due to inversion, and with it, a dangerous
increase in air pollution.

5. Building design
The main points
 Orientation and room placement, for optimal response to sun and wind.
 Form, providing protection where required.
 Shade, as much as required.
 Ventilation, by excluding climatically adverse side-effects.
Orientation of buildings
To define the optimal orientation of a building, three factors have
to be considered:
• Solar radiation
• Prevailing wind
• Topography
What is the optimal orientation ?
Where are large openings, small or no openings desirable ?
What kind of structure and shading devices are appropriate for a
given surface ?
Optimal sun-orientation reduces radiation to a minimum in the hot periods, while
allowing adequate radiation during the cool months.
East and west facing walls receive the highest intensities of radiation, especially
during the hot periods.
These walls should thus normally be kept as small as possible and contain as few
and small openings as possible.

6. Advantages of vegetation
Landscaping using vegetation has many advantages:
• It improves the microclimate both outdoors and indoors
• It checks hot and dusty winds in arid regions
• Through the transpiration of leaves temperatures are lower
• Its shade lowers daytime temperatures and heat emission at night
is also reduced, thus resulting in more balanced temperatures.
• It balances the humidity. During precipitation much of the free
water is absorbed and during dry periods water is evaporated.
Plants offer long term energy saving free of cost, both in financial
and in ecological terms.

7. Topographical orientation
Where the solar heat form reflection and radiation is not desired, the orientation of the building should be
changed or the surface of the surroundings should be covered with greenery that improves the
microclimate.
The topography may also alter the prevailing wind and provide shade at certain time of the day. Such
elements should also be considered.
Shape and volume
The functional as well as socio-cultural requirements and particularly the climatic conditions define the
form of the buildings.
The heat exchange between the building and the environment depends greatly on the exposed surfaces.
A compact building gains less heat during the daytime and loses less heat at night.
Therefore, the ratio of surface to volume is an important factor.
Volume Surface Ratio
a) as individual
bungalows
1764 m³ 1596 m² 1:1.
b) as row
houses
1764 m³ 1134 m² 1:1.6
c) as compact
3-story building
1764 m³ 700 m² 1:2.5