shelter for composite climate -...

SHELTER FOR COMPOSITE

CLIMATE

Nature of the climate

Neither consistently hot and dry , nor warm and

humid.

Characteristics change from season to season.

Significant differences in air temperature , humidity

, wind , sky and ground conditions

Physiological objectives

Set out for warm humid and hot dry climate apply

to the respective seasons of composite climate.

The designer tries to increase the heat dissipation in

warm season and vice-versa in cold season

according to the physical comfort.

Design Criteria

Average Temperature of Islamabad

Seasons Month Discomfort

level

Durati

on

Index Percentage

Hot dry May +3⁰C 1

month

3

June +5.5⁰C 1 5.5

Seasonal

total

8.5 13.5

Warm humid July +8⁰C 1 8

August +6.5⁰C 1 6.5

September +4.5⁰C 0.5 2.25

Seasonal

total

16.75 26.5

Cold dry November -8⁰C 0.3 02.4

December -11⁰C 1 11

January -11⁰C 1 11

February -10⁰C 1 10

March -6.5⁰C 0.5 3.25

Seasonal

total

37.65 60

Annual total 62.9 100

Discomfort Index = discomfort level x duration

Form And Planning

Compact internal

planning

Courtyard type

buildings

Dense low rise development for

o Mutual shading of external walls.

o Shelter from wind in cold season.

o Shelter from dust.

o Reduction of surfaces exposed to solar radiation.

Separate day and

night rooms are

preferable for the

hottest month.

EXTERNAL SPACES

Large projecting eaves and wide verandahs

o To reduce sky glare and provide shade

o To keep out the rain

Brise-soleils, louvers and

other sun breaks

o To protect openings

o Serve as protection

against rains

Pergolas

o To provide shade in hot season but admit the sun in

the winter

Roofs and walls

More time lag – Thick solid walls , concrete walls .

Thermal capacity is an advantage in both cold and try season .

In warm humid climate – low thermal capacity , good insulating wall and roof .

Thermal capacity in floors , partitions and ceiling .

Resistance insulation provided only in external walls .

Advantage of low rise development .

Low thermal capacity

More time lag

Thermal storage

Surface Treatment

In cold seasons – absorbing

surface .

Light color

• Surface exposed to sun –

in hot and warm seasons

Dark color

OPENINGS

Orientation

Towards breeze prevailing- warm humid season-for

cooling effect.

Towards sun-cold season-for heating effect

VENTILATION AND CONDENSATION

Best protection is to use to use porous and moisture

absorptive materials

Traditional Shelter

Relative predominance

of hot dry or warm

humid conditions.

An urban solution for

housing is ground floor

with massive walls with

large shuttered

openings, laid out

around a courtyard ,

and a first floor

structure of light

weight materials.

The walls of floors cool

quickly at night

because they are made

up of light weight

materials, to allow

fairly comfortable

sleeping condition .

SHELTER FOR TROPICAL

UPLAND CLIMATES

Nature of the climate

This climate is similar to composite climates , with its

distinct rainy seasons.

Strong solar radiation.

Temperature rarely reaches 30degC.

Maximum diurnal variation 20degC.

No excessive humidities.

Almost constant air movement , never very strong.

Physiological Objectives

Air temperature rarely

exceeds the upper

comfort limit.

Protection against

overheating-

o Adequate shading for

windows.

o By limiting heat

admission like

insulation of walls

By provision of adequate ventilation.

FORM AND PLANNING

Orientation of the building and its major openings

greatly influence the solar heat gain.

Solar radiation hierarchy :

West > east = south west = north west > south >

north

North and south : Longer walls and major openings.

West : openings should be avoided.

EXTERNAL SPACES

Adjustable shading devices : pergolas, awnings

Alternative external spaces for use in different

seasons where space is not a premium.

Shade can be provided by the building itself

Roofs and Walls

For offices – 5 hours of time lag

light weight walls in multi storage building .

Good insulation and shaded windows .

Limit heat during day time

Store heat during night time

For residency – time lag of 8 hours and high thermal capacity structure

-east and west facing walls should be massive

- north and south facing walls are light weighing

More time lag

Less time lag

Surface Treatment

For day time buildings – white and reflective

surfaces can be used .

For continuous – fabric is

used to store heat for night

and dark , more absorbent

surface finish .

Building with high thermal

capacity .

Roof – 8 hour time lag

Black bituminous or asphalt finish – absorbs solar heat during day and release after sunset

For light weigh roof –bituminous polished roof is covered with aluminum or marble chips .

At high altitudes well tested material should be used .

Polished with bituminous

OPENINGS

No need for physiological cooling by air movement

No need for cross ventilation-feeling of cold

discomfort

BUT where soar overheating does occur, cross

ventilation may provide relief

Closing of openings and less opening(20% of

elevational area)- easier to control solar heat gain

Traditional shelter

Traditional rural

shelter-

o Round huts.

o Mud and wattle walls.

o Thatched roof.

Plastered with mud.

Maximum thickness of

0.25m, for substantial

thermal capacity.

Urban areas-

o Stone masonry walling.

o Slate roofs.

Roof may be thatched

or of wood framework.

Plastered with mud.

Small openings.

THANK YOU!!!

Aabha 12SA101

Ankita 12SA104

Anmol 12SA105

Pratyashi 12SA127

Divyakshi 12SA152