VERNACULAR ARCHITECTURE IN COLD AND SUNNY CLIMATE

Indian vernacular architecture is the informal, functional architecture of structures, often in rural areas of India build of local material to meet local requirements

The builders involved are basically unschooled in informal architectural design and their work reflects the rich diversity of India's climate, locally available building material.

METHODOLOGY

Architects can achieve energy efficiency in the buildings they design by studying the macro and microclimate of the site, applying bioclimatic architectural principles to combat the adverse conditions, and taking advantage of the desirable conditions. A few common design elements that directly or indirectly affect thermal comfort conditions and thereby the energy consumption in a building are listed below:1.Site (a) Landform (b) Open Spaces And Built Forms (c) Street Width And Orientation2.Orientation And Planform3.Building Envelope (a) Roof (b) Walls (c) Fenestration (d) Colour And Texture4.Techniques (a) Glazing (b) Trombe Wall (c) Waterwall (d) Roof Based Air Heating System (e) Sunspaces

SITELandform

a) In cold climates, heat gain is desirable. Hence, buildings should be located on the south slope of a hill or mountain for better access to solar radiation

b) Exposure to cold winds can be minimized by locating the building on the leeward side.

c) In case the southern side is the windward side. The building should be glazed in such a manner that minimum wind enters the building. Parts of the site which offer natural wind barrier can be chosen for constructing a building

(b(c) Street Width And Orientation In cold climates, the street orientation should be east-west to allow formaximum south sun to enter the building. The street should be wide enough to ensure that the buildings on oneside do not shade those on the other side (i.e. solar access should beensured)

Open Spaces And Built Form

a) Buildings can be clustered together to minimize exposure to cold winds.

b) Open spaces between buildings must be such that they allow maximum solar rays to be incident on the building.

c) They should be treated with a halt and reflective surface so that day reflect solar radiation onto the building.

ORIENTATION AND PLANFORM

1. Buildings must be compact with small surface to volume ratios to reduce heat loss.

2. Windows should face south to facilitate direct gain3. The north side of the building should be well-insulated4. Living areas can be located on the southern side while utility are as

such as stores can be on the northern side.5. Air-lock lobbies at the entrance and exit points of the building

reduce heat loss. Heat generated by appliances in rooms such as kitchens may be used to heat the other parts of the building.

Street Width And Orientation

a) In cold climates, the street orientation should be east-west to allow for maximum south sun to enter the building.

b) The street should be wide enough to ensure that the buildings on one side do not shade those on the other side (i.e. solar access

should been sured)

BUILDING ENVELOPE

(a) Roof False ceilings with internal insulation such as polyurethane foam (PUF), thermocol , wood wool, etc. are feasible for houses in cold climates.

(b) Aluminium foil is generally used between the insulation layer and the roof to reduce heat loss to the exterior.

(c) A sufficiently sloping roof enables quick drainage of rain water and snow.

(d) A solar air collector can be incorporated on the south facing slope of the roof and hot air from it can be used for space heating purposes.

(a)Skylights on the roofs admit heat as well as light in winters. Skylights can be provided with shutters to avoid over heating in summers

(b) Walls should be made of materials that lose heat slowly.(c) The south-facing walls (exposed to solar radiation) could be of high

thermal capacity (such as Trombe wall) to store day time heat for later used.

(d) The walls should also be insulated. The insulation should have sufficient vapour barrier (such as two coats of bitumen, 300 to 600 gauge polyethylene sheet or aluminium foil) on the warm side to avoid condensation.

(e) Hollow and lightweight concrete blocks are also quite suitable.(f) Skylights can be provided with shutters to avoid over heating in

summers(g) On the windward or north side, a cavity wall type of construction

maybe adopted.

Fenestration

a) It is advisable to have the maximum window area on the southern side of the building to facilitate direct heat gain.

b) They should be sealed and preferably double glazed to avoid heat losses during winter nights. Condensation in the air space between the panes should be prevented,

c) Movable shades should be provided to prevent overheating in summers.

d) Colour And Texturee) The external surfaces of the walls should be dark in colour so that

day absorb heat from the sun.

 TECHNIQUES

(a)Glazing South facing glazing is ideal for cool temperate climates. It allows maximum solar access in winter and can be easily shaded in summer. In cool temperate climates:

(b) Maximize South facing glazing with solar exposure (especially in living areas).

(c) Minimize east & west facing glazing(d).• Use adjustable shading. Insulating glass unit with low-e(e)• Use insulating glass and frames and/or snug fitting insulating

drapes with sealed pelmets.

Trombe Wall• A Trombe wall is a thermally massive wall with vents provided at the top and bottom. It may be made of concrete, masonry, adobe, and is usually located on the southern side (in the northern hemisphere) of a building in order to maximize solar gains.• The outer surface of the wall is usually painted black for maximizing absorption and the wall is directly placed behind glazing with an air gap in between.• Solar radiation is absorbed by the wall during the day and stored as sensible heat. The air in the space between the glazing and the wall gets heated up and enters the living spaces by convection through the vents.• Cool air from the rooms replaces this air, thus setting up a convection current. The vents are closed during night, and heat stored in the wall during the day heats up the living space by conduction and radiation.• The trombe wall should be adequately shaded for reducing summer gains.

Water Wall

• A water wall is a thermal storage wall made up of drums of water stacked up behind glazing. It is usually painted black to increase heat absorption.• It is more effective in reducing temperature swings, but the time lag is less.•Heat transfer through water walls is much faster than that for trombe walls.• Buildings that work during the daytime, such as schools and offices, benefit from the rapid heat transfer in the water wall.• Overheating during summer may be prevented by using suitable shading devices.

Roof-Based Air Heating System

• In this technique, incident solar radiation is trapped by the roof and is used for heating interior spaces.• In the Northern Hemisphere, the system usually consists of an inclined south-facing glazing and a north-sloping insulated surface on the roof. Between the roof and the insulation, an air pocket is formed, which is heated by solar radiation.• A moveable insulation can be used to reduce heat loss through glazed panes during nights.• There can be variations in the detailing of the roof air heating systems. Climate Roof base air heating system for winter heating in Himachal Pradesh State Cooperative Building.• In the Himachal Pradesh State Cooperative Bank building, the south glazing is in the form of solar collectors warming the air and a blower fan circulating the air to the interior spaces.

Sunspace

• A sun space or solarium is the combination of direct and indirect gain systems.• The solar radiation heats up the sun space directly, which in turn heats up the living space(separated from the sun space by a mass wall)by convection and conduction through the mass wall. In the northern hemisphere, the basic requirements of buildings heated by sunspace are :(a) a glazed south facing collector space attached yet separated from

the building(b) (b) Living space separated from the sun space by a thermal storage

wall. Sunspaces may be used as winter gardens adjacent to the living space. The Himurja building in Shimla has well designed solarium as integral part of south wall to maximize solar gain.

LEH, LADAKHCOLD AND SUNNY CLIMATE

Mountainous region Little vegetation Considered to be a ‘Cold Desert’

LEH

COLD and SUNNY type of climate is experienced here.

TEMPERATURE VARIATIONS• Summer during day : 17 - 24°Cduring night : 4 - 11°C• Winterduring day : 7 - 9°Cduring night : -14 – 0 °C

Relative humidity – consistently low : 10-50% Winds – occasionally intense Sky is fairly clear throughout the year Cloud cover is less than 50%

CLIMATE

DESIGN CRITERIA AND FEATURESOBJECTIVES

PHYSICAL MANIFESTATION

Resist heat loss Decrease exposed surface area

Increase thermal resistance

Increase thermal capacity (Time lag)

Increase buffer spaces Decrease air exchange rate Increase surface absorptivity

Promote heat gain Reduce shading Utilize heat from appliances Trapping heat

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 colors

Walls and glass surfaces

Sun spaces/ green houses/ Trombe walls etc

TREES –wind barrier

Roof & wall insulation

Thick walls

Heavy walls (mud) and a well insulated roof (timber & mud) dampen the variations of indoor temperatures.

Use of glass and trombe wall – heat is stored in the building mass during the day and warm during the night

City of some 25,000 inhabitants

Population triples in size during summer tourist season

OLD LEH• 200 stone, mud and timber houses sandwiched between thick rammed earth walls

• Most well-preserved traditional Tibetan city in the world

• Most significant ensemble of historic Tibetan architecture

• One makes the walls for the first floor, piling up stone and sun-dried brick, • and then places wooden beams and floor joists across the walls to support the second floor walls above them, • and repeatedly adds more wooden beams across them. • Floors and roofs are made of mud treaded on wooden boards. • Roofs are basically flat, being unnecessary to waterproof, since it scarcely ever rains.• Columns are needed midway across larger spans

• First floor - used for stables • Second floor – for family rooms, such as a sitting room, a kitchen, bedrooms, and a Buddhist altar room • A larger house often consists of three floors. 

Porch

Kitchen

Dining

Bedroom