SHELTER FOR COMPOSITE CLIMATE

Transcription

1 SHELTER FOR COMPOSITE CLIMATE

2 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

3 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.

4 Design Criteria Average Temperature of Islamabad

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6 Seasons Month Discomfort level Durati on Index Percentage Hot dry May +3⁰C 1 month 3 June +5.5⁰C Seasonal total Warm humid July +8⁰C 1 8 August +6.5⁰C September +4.5⁰C Seasonal total

7 Cold dry November -8⁰C December -11⁰C 1 11 January -11⁰C 1 11 February -10⁰C 1 10 March -6.5⁰C Seasonal total Annual total Discomfort Index = discomfort level x duration

8 Form And Planning Compact internal planning Courtyard type buildings

9 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.

10 Separate day and night rooms are preferable for the hottest month.

11 EXTERNAL SPACES Large projecting eaves and wide verandahs o o To reduce sky glare and provide shade To keep out the rain

12 Brise-soleils, louvers and other sun breaks o o To protect openings Serve as protection against rains

13 Pergolas o To provide shade in hot season but admit the sun in the winter

14 Roofs and walls Low thermal capacity More time lag 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. Thermal storage

15 Surface Treatment Surface exposed to sun in hot and warm seasons In cold seasons absorbing surface. Light color Dark color

16 OPENINGS Orientation Towards breeze prevailing- warm humid season-for cooling effect. Towards sun-cold season-for heating effect

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18 VENTILATION AND CONDENSATION

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20 Best protection is to use to use porous and moisture absorptive materials

21 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.

22 The walls of floors cool quickly at night because they are made up of light weight materials, to allow fairly comfortable sleeping condition.

23 SHELTER FOR TROPICAL UPLAND CLIMATES

24 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.

25 Physiological Objectives Air temperature rarely exceeds the upper comfort limit. Protection against overheatingo o Adequate shading for windows. By limiting heat admission like insulation of walls

26 By provision of adequate ventilation.

27 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.

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29 EXTERNAL SPACES Adjustable shading devices : pergolas, awnings

30 Alternative external spaces for use in different seasons where space is not a premium. Shade can be provided by the building itself

31 Roofs and Walls For offices 5 hours of time lag light weight walls in multi storage building. Good insulation and shaded windows. More time lag Less time lag 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

32 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.

33 Polished with bituminous 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.

34 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

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36 Traditional shelter Traditional rural sheltero o o Round huts. Mud and wattle walls. Thatched roof. Plastered with mud. Maximum thickness of 0.25m, for substantial thermal capacity.

37 Urban areaso o Stone masonry walling. Slate roofs. Roof may be thatched or of wood framework. Plastered with mud. Small openings.

38 THANK YOU!!! Aabha 12SA101 Ankita 12SA104 Anmol 12SA105 Pratyashi 12SA127 Divyakshi 12SA152