CLIMATOLOGY

CLIMATIC ZONE OF INDIA

“COMPOSITE”

1. HOT AND DRY

2. HOT AND HUMID

3. COMPOSITE

4. COLD

5. MODERATE

• NEW DELHI • HIMACHAL PRADESH• PUNJAB• HARYANA• UTTAR PRADESH• MOST OF MADHYA PRADESH & CHATTISGARH• PARTS OF HIMACHAL PRADESH, RAJASTHAN, MAHARSHTRA, KARNATAKA, ANDHRA PRADESH, GUJARAT, JHARKHAND, UTTARANCHAL, WEST BENGAL AND ORISSA

SUMMERS IN COMPOSITE CLIMATE

WINTERS IN COMPOSITE CLIMATE

MONSOON IN COMPOSITE CLIMATE

TALKING ABOUT DELHI’S CLIMATE

THE DISTANCE FROM THE SEA GIVES SOUTH WEST DISTRICT OF DELHI AN EXTREME TYPE OF CONTINENTAL CLIMATE. THE SUMMERS IN EAST-DELHI

ARE VERY HOT AND WINTERS VERY COLD. THE TEMPERATURE RANGE VARIES FROM 45 DEGREES IN SUMMERS TO 4 DEGREES IN WINTERS. THE WINTERS ARE MARKED BY MIST AND FOG IN THE MORNINGS AND OFTEN

SUN IS SEEN IN THE AFTERNOONS. THE COLD WAVE FROM THE HIMALAYAN REGION MAKES WINTERS VERY CHILLY. IN SUMMERS THE

HEAT WAVE IS IMMENSE AND ADEQUATE PRECAUTION HAS TO BE TAKEN BEFORE GOING OUT IN THE HOT SUMMER AFTERNOONS.

THE BEST SEASON TO VISIT SOUTH WEST DISTRICT OF DELHI IS DURING THE SPRING SEASONS OF FEBRUARY TO APRIL AND AUGUST TO

NOVEMBER. THE BLOOM SEASON OF FEBRUARY AND MARCH MAKE SOUTH WEST DISTRICT OF DELHI COLORFUL. THIS TIME OF THE YEAR

BRINGS GREENERY ON THE FACE OF SOUTH WEST DISTRICT OF DELHI.

OBJECTIVE OF BUILDING IN THESE REGIONS(A) RESISTING HEAT GAIN UNWANTED HEAT GAIN CAN BE REDUCED BY• DECREASING THE SURFACE AREA OF THE BUILDING EXPOSED TO THE OUTSIDE.• USING MATERIALS THAT ABSORB HEAT SLOWLY.• PROVIDING BUFFER SPACES.• PROVIDING ADEQUATE SHADING DEVICES.

(B) PROMOTING HEAT LOSS TO PROMOTE HEAT LOSS, THE FOLLOWING MEASURES NEED TO BE UNDERTAKEN:1. VENTILATING APPLIANCES USED.2. PROVIDING EVAPORATIVE COOLING SYSTEMS LIKE ROOF SURFACE.3. EVAPORATIVE COOLING.4. USING EARTH COUPLING SYSTEMS LIKE EARTH AIR PIPE SYSTEM.

(C) PROMOTING VENTILATIONINCREASING THE RATE OF VENTILATION DURING COOLER PARTS OF THE DAY OR NIGHT-TIME AND DURING THE HUMID PERIODS IS A NECESSITY IN COMPOSITE CLIMATIC AREAS.

GENERAL RECOMMENDATIONS FOR THE CLIMATE ARE: (1) SITE (A) LANDFORM REGIONS IN THIS ZONE ARE GENERALLY FLAT AND HEAT UP UNIFORMLY. (B) WATERBODIES LIKE PONDS AND LAKES ACT AS HEAT SINKS AND CAN ALSO BE USED FOR EVAPORATIVE COOLING.

FOUNTAINS AND WATER CASCADES IN THE VICINITY OF A BUILDING ALSO AID IN COOLING.

HOWEVER, IT HAS TO BE ENSURED THAT THESE WATER BODIES DO NOT INCREASE THE RELATIVE HUMIDITY DURING THE HUMID SEASONS.

(C) STREET WIDTH AND ORIENTATION STREETS MUST BE NARROW SO THAT BUILDINGS MUTUALLY SHADE EACH OTHER. THEY NEED TO BE ORIENTED IN THE NORTH-SOUTH DIRECTION TO BLOCK SOLAR RADIATION.

(D) OPEN SPACES AND BUILT FORMOPEN SPACES SUCH AS COURTYARDS AND ATRIA PROMOTE VENTILATION. COURTYARDS ACT AS HEAT SINKS DURING THE DAY AND RADIATE THE HEAT BACK AT NIGHT.

GRASS CAN BE USED AS GROUND COVER TO ABSORB SOLAR RADIATION AND AID EVAPORATIVE COOLING.EARTH BERMING CAN HELP LOWER THE TEMPERATURE AND ALSO DEFLECT HOT SUMMER WINDS.

(2) ORIENTATION AND PLANFORM AN EAST-WEST ORIENTATION IS PREFERRED AS NORTHERN AND SOUTHERN WALLS ARE EASIER TO SHADE. CROSS-VENTILATION MUST BE ENSURED AT NIGHT AS AMBIENT TEMPERATURES DURING THIS PERIOD ARE LOW.

(3) BUILDING ENVELOPE (A) ROOF 1. FLAT ROOFS MAY BE USED IN THIS CLIMATE. 2. A MASSIVE ROOF STRUCTURE LIKE A REINFORCED CEMENT CONCRETE RCC SLAB IS PREFERABLE OVER AN ASBESTOS CEMENT AC SHEET ROOF. 3. A FALSE CEILING IN ROOMS HAVING EXPOSED ROOFS CAN HELP IN REDUCING THE DISCOMFORT LEVEL. 4. EVAPORATIVE COOLING OF THE ROOF SURFACE AND NIGHT-TIME RADIATIVE COOLING ARE MEASURES THAT CAN ALSO BE EMPLOYED TO IMPROVE COMFORT LEVELS. 5. THE SURFACE OF THE ROOF CAN BE OF WHITE BROKEN GLAZED TILES.

HOW THE EVAPORATIVE COOLING ROOFS WORK?

(B) WALLS 1. IN MULTI-STOREYED BUILDINGS, WALLS AND GLAZING ACCOUNT FOR MOST OF THE HEAT GAIN. SO, THE CONTROL OF HEAT GAIN THROUGH THE WALLS BY SHADING IS AN IMPORTANT CONSIDERATION IN BUILDING DESIGN. 2. A WALL THAT TAKES A LONGER TIME TO HEAT UP REDUCES THE HEAT GAIN.

CONCLUSION

AS THE WINTERS IN THIS REGION ARE UNCOMFORTABLY COLD, WINDOWS SHOULD BE DESIGNED SUCH THAT THEY ENCOURAGE DIRECT GAIN OF

SOLAR HEAT DURING THIS PERIOD.

DECIDUOUS TREES CAN BE USED TO SHADE THE BUILDING DURING SUMMER AND ADMIT SUNLIGHT DURING WINTER.

WELL-INSULATED AND VERY THICK WALLS GIVE A GOOD THERMAL PERFORMANCE IF THE GLAZING IS KEPT TO A MINIMUM AND WINDOWS ARE

WELL SHADED.

IN CASE OF NON-CONDITIONED BUILDINGS, A COMBINATION OF INSULATED WALLS AND HIGH PERCENTAGE OF GLAZING WILL LEAD TO

VERY UNCOMFORTABLE INDOOR CONDITIONS.

INDOOR PLANTS CAN BE PROVIDED NEAR THE WINDOW, AS THEY HELP IN EVAPORATIVE COOLING AND IN ABSORBING SOLAR RADIATION.