Geographic coordinates of Leh, IndiaLatitude: 34°10′00″ N Longitude: 77°34′59″ E Elevation above sea level: 3599 m

LOCATION

COLD AND DRY

The cold and sunny type of climate is experienced in Leh (Ladakh).

The region is mountainous, has little vegetation, and is considered to be a cold desert.

The solar radiation is generally intense with a very low percentage of diffuse radiation.

In summer, the temperature reaches 17 – 24 ºC during the day and 4 – 11 ºC at night.

In winter, the values range from -7 to 8 ºC during the day and -14 to 0 ºC at night. Winters thus, are extremely cold.

The relative humidity is consistently low ranging from about 10 – 50 %.

precipitation is generally less than 200 mm per year. Winds are occasionally intense.

The sky is fairly clear throughout the year with a cloud cover of less than 50%.

As this region experiences cold desert climatic conditions, the design criteria are to resist heat loss by insulation and controlling infiltration.

Simultaneously, heat gain needs to be promoted by admitting and trapping solar radiation within the living space.

AVERAGE HIGH AND LOW TEMPERATURE

RELATIVE HUMIDITY

Rainfall

SOLAR CHART

INFERENCE

. South face receives the maximum sun radiation. Therefore maximum fenestration in this climate are given on the south façade

North Face receives almost zero sunlight , so this face has no fenestrations

WIND CHART

BIOCLIMATIC CHARTLeh (Latitude: 34.15o N,

Longitude: 77.57° E, Elevation:3514 MASL)

The chart (Fig. 2.23) shows that Leh is predominantly cold throughout the year. Outside

conditions are rarely within the comfort zone except during daytime in the months of July and

August. In fact, the months of December, January and February experience sub-zero temperatures

almost throughout the day and night.

MAHONEY'S TABLE

GENERAL INFERENCES

O R I E N TAT I O N N O R T H A N D S O U T H ( L O N G A X I S E - W )

C O M PA C T L AY O U T O F E S TAT E S

N O A I R M O V E M E N T R E Q U I R E D , V E R Y S M A L L O P E N I N G S , 1 0 - 2 0 %

H E A V I E X T E R N A L A N D I N T E R N A L W A L L S , H E A V Y R O O F S , O V E R 8 H T I M E L A G

Objectives: Resist heat loss

Decrese exposed surface area

Increse thermal resistance

Increase thermal capacity

Increase buffer space Decrease air exchange

rate Increase surface

absorbtivityMAHONEY’S INFERFERENCES

Promote Heat Gain• Reduce shading• Utilize heat from appliances• Trapping heat

PHYSICAL MANIFESTATION

Orientation and shape of building

Use of trees as wind barriers

Roof insulation wall insulation and double glazing

Thicker walls

Air locks/lobbies

Weather stripping

Darker kolors

Walls and glass surface

Sun spaces/green house/trombe wall etc.

PASSIVE STRATEGIES

INTRODUCTION:Generally building design should be passive as far as possible

to minimize the need for energy input. If this solution is not satisfactory complementary hybrid or active system may be used. However, these systems should be simple and cheap and should meet system requirements.• The various criteria's for which passive heating are used

while designing a building are:

• Heating/Cooling• Orientation• Thermal mass of material• Shading devices• Natural ventilation• Water strategies• Building form

PASSIVE HEATING

Twin wall material should be used for roofing and a layer of exterior glass with inner layer of acrylic to maximise the heat gain by solar light dur to green house effect.

Materials• Materials with high thermal mass such as concrete can maintain a temperature by absorbing heat from the day and then radiating it in night

• Roofs should be insulated by materials such as rock wool , wood fibre etc. and should be externally be covered by corrugated aluminum sheets.

• Timber frame should be used

DESIGN IMPLICATIONS

OrientationBuilding in this type of klimate should have North-South

orientation

Maximum windows should be on the South side since it receives maximum sunlight.

Location• Building a pit style building is appropriate for prevention of winds.By moving the building 2-3 feet down, the exposure to wind is reduced and also the temperature of the floor is maintained since ground temperature is high.

• The building should be located away from the river since cold winds flow along it.

• The building should always be made down the slope or valleys in hilly terrain and to top of it should be covered with thick vegetation to prevent damage from the chilly winds.

STREET LAYOUT

In cold climate, wide streets especially the east west streets allow buildings to receive the south sun.

North-South streets should be narrow and buildings should be low in height

Internal Layout

• The layout of the building is highly compact so as to maximize heat loss.

• Bedrooms and living rooms areas have to be warmer than the store rooms and can be used as a buffer between warm living and cold outdoor.

VENTILATION AND OPENINGS

FENESTRATIONS

Fenestrations should be large, unshaded but sealed.This would enable the heat gain but reduce cool breeze.

Fenestration should be on the south façade of the building.

Surface Area/Volume Ratio• In cold-dry climate the s/v ratio should be as low as

possible to minimise heat losses.• Greater the surface area more heat gain/loss

Shading Devices• In cold and dry climate no shading for fenesration is

required.• Optimum glazing in desireable, hence to avoid glare

vertical shading devices with low projections can be provided.

PLANTING TREES IN COLD AND DRY REGION

• It saves life by preventing and slowing down of mud slides and avalanches.

• Protects water qualities by capturing rainfall.

• Improves the air quality.

• Lower summer temperatures

• Serves as wildlife habitat.

• Raises awareness of global climate change in most fragile region on earth.

Tree Height Girth

Apple tree 3-12 meters 6 meters

Apricot tree 8-12 meters 7.5 meters

Walnut tree 30-40 meters 1.5 meters

Mulberry tree 8-10 meters 21 meters

VERNACULAR ARCHITECTURE IN LEH

Traditional tibetian architecture is well suited to the climate and geography of Leh.

Sun-dried mud bricks can be made on site without specialized skills . They are the cheapest building material but also have very good insulation qualities.

Roofing is done by placing willow joists over the rafters, then applying the traditional layering of mud and clays. If done correctly, the traditional roofing method is very efficient and can last for a long time. This provides a good insulation and does not allow heat to escape easily

Thick mud plaster is used to create

Additional insulation layers. Walls are

sometimes fitted with partly-timbered

frames for structural stabilization.

Mud plaster absorb heat from strong

sunshine during day and slowly radiate it

during cold night.

Mud is used in many layers to provide

insulation for walls, floors and ceilings.

Some houses are built at the downward slope of the hill.

Such houses have practically no openings except a door for light and

ventilation.

Such houses are well equipped to retain heat.

Such houses are also built from mud and timber.

SOLARIUM

A solarium refers to a sun room built largely of glass to afford exposure to the sun.

It also provides the view of the adjoining landscape with providing shelter from cold winds.

It traps sunlight and heat by the green house effect mechanism.

TROMBEY WALLS

A trombey wall is a sun facing wall separated from the outdoors by glass and an air space.

It absorbs solar energy and releases it selectively towards the interior at night.

Modern trombey walls have vents added to top and bottom to allow the heated air to flow via convection into the building interior.

The vent have one way flaps to prevent the convection in opposite direction.