CLIMATE RESPONSIVE ARCHITECTURE
Rethinking tradition: Passive housing in the desert, Jaisalmer, Rajasthan, India
Archana Prasad SEMESTER - 3
Jaisalmer is situated towards the western portion of Thar desert at latitude 26 degree 54 minutes N and longitude 70 degree 55 minutes E. The climate is influenced by its position amidst the great Indian desert. The region experiences arid climate throughout the year. The surrounding region is rocky and barren, relieved by sparse, scrubby weeds, but no trees. Jaisalmer falls at more extreme end of hot dry climate, within which can be identified four different seasons, pre-monsoon, monsoon, post-monsoon and winter. Pre-monsoon, which is the hottest season, extends from April to June, with the daytime temperature often exceeding 45 degree C, cooling down to a minimum of 26 degree C at night. Monsoon arrives in mid-July. The daytime temperature reaches a peak value of around 36 degree C, and during night time conditions have minimum temperature of around 28 degree C. The third season is post monsoon, starting early to mid September, daily temperatures range from about 20 degree C at night to over 35 degree C in daytime. The final season is winter, which extends from December to March, January being the coldest month. The daytime temperatures for this period peak in middle twenties, dropping to less than 10 degree C at night. Solar radiation is intense throughout the year – 800-950 W/m^2. Apart from very short monsoon season, relative humidity is very low (25-40%), with precipitation generally less than 500mm/year. The prevailing wind direction is south westerly but for four months of the year, November through to February, the wind blows from North-East.
Hot winds blow during the day in summers and sand storms are also experienced. The night is usually cool and pleasant. A generally clear sky, with high solar radiation causing an uncomfortable glare, is typical of this zone. As the sky is clear at night, the heat absorbed by the ground during the day is quickly dissipated to the atmosphere. Hence, the air is much cooler at night than during the day. In such a climate, it is imperative to control solar radiation and movement of hot winds. The design criteria should therefore aim at resisting heat gain by providing shading, reducing exposed area, controlling and scheduling ventilation, and increasing thermal capacity. The presence of water bodies is desirable as they can help increase the humidity, thereby leading to lower air temperatures. SOIL AND VEGETATON Jaisalmer region has sand that varies from sandy to sandy loam. The soil is dusty and very dry. Soil dries quickly after the rain and generally the soil can be fertile if irrigated. Vegetation is sparse and difficult to maintain because of the lack of rain and low humidity. Due to lack of availability, vegetation comprises of only thorny bushes and cacti. There is only seasonal vegetation such as few grass species, shrubs and dwarf trees.
Rethinking tradition: Passive housing in the desert, Jaisalmer, Rajasthan, India.
CLIMATE RESPONSIVE ARCHITECTURE
Dense clustering is seen in this street view of Jaisalmer. Streets are narrow and are mostly E-W oriented. Dense construction is observed on both sides of the road. These streets are shaded through orientation and structural projections.
The height of the building id generally 3 times the width of the road. The “Jharokhas“ (a type of overhanging balcony seen in Havelis in Jaisalmer) shade the street. “Compartmentalization ” is done in the building to restrict the harsh sunlight reach the interiors.
The facades of the buildings are finely carved into various geometrical patterns giving the appearance of latticework (jali); creating a rough texture. The sandstone walls and the limestone used for carving are light in colour and provide a permanent natural finish.
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ARCHANA PRASAD Prasad Archana USN 01FA16BAT013 USN 01FA16BAT013 SEMESTER 3 Semester – 3 KLETU
KLETU
Depending upon the socio economic status of the inhabitant, there are three types of houses in Jaisalmer. The simplest town house consists f a single room, a verandah and a courtyard. Larger houses of this type have another verandah over the entrance and some houses have an additional room on one side of the courtyard. Three single storey structures are owned by the poorest people and have been built in the Small houses in Jaisalmer peripheral areas of the town. The second type of house belongs to the middle-income people. A two or thee-storey structure, this house type can be considered the typical house of Jaisalmer. It is similar to the first house type in plan, with the only difference that additional rooms and small enclosed terraces are located at the upper floors. The front part of the first floor has a balcony projecting onto the street.
The houses have small openings for visual connectivity.
AIR DUCT
COURTYARD
Jali walls
The windows are placed at lower level so that the cool air enters the building and the hot air rises and exits the building through the ventilators placed above the sill level.
Middle income houses in Jaisalmer
PATWA HAVELI This haveli is a six floor building consisting of three main floors, two wind pavilions and a basement floor. The courtyard at the ground is surrounded by verandah on all sides with additional row of rooms in front and the back of the haveli.
AIR DUCT COURTYARD To facilitate the moment of cool air into the house, The air enters the building through the air ducts. parapets are not built towards the courtyard
The hot air exits the building through the courtyard
Rethinking tradition: Passive housing in the desert, Jaisalmer, Rajasthan, India.
CLIMATE RESPONSIVE ARCHITECTURE
The building projects out on every floor both towards the street and the courtyard. The two connecting staircases act as a wind shafts. Also, the entire street facade is covered with stone carved finned surfaces, balconies and sun shade
The dense construction around the street completely shades it. SHEET NO. SHEET NO.
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ARCHANA PRASAD Prasad Archana USN 01FA16BAT013 USN 01FA16BAT013 SEMESTER 3 Semester – 3 KLETU
KLETU
TYPES OF SHADING DEVICES IN HAVELI JHAROKHAS : a type of overhanging balcony CHATRI : elevated dome shaped pavilions CHAJJA : projecting eaves or cover usually supported on large brackets. JALIS : perforated stone or lattice screen used for ventilation. In Jaisalmer it is ensured that individual buildings were not exposed to sun. Dense clustering not only prevents heat gain but it also keeps hot winds out while ensuring movement of cooler air through the buildings and open areas. To avoid the heating of interior space it is essential to treat air before it enters the building. A great deal of attention was given to pretreatment of ventilation in traditional building. The air enters the building only after travelling through a tall tower with thick walls and sometimes even through an underground tunnel where it cooled down due to contact with cool walls of the duct. The courtyard effect was used to ventilate the building surfaces in the street. Measured airflow in Jaisalmer shows how the courtyard plan regulates air movement, bringing in fresh air only when it is cooler than the building.
BUILDING CONSTRUCTION The common building material used in Jaisalmer is stone. Light yellowish sandstone is used for walls, which are 0.45m or more in thickness. In better quality construction the stone is dressed and joints are made accurately without any mortar. In poorer people’s houses the stone is undressed and the walls are built in mud-mortar and finished with mud plaster. At upper floor level, where the building façade projects out, 50mm thick panels of limestone are used as wall elements.
Also the buildings had a plinth of 0.9m or more to prevent the sandy winds entering the building. In havelis the plinth was also finely carved and decorated.
Shadow pattern in N-S orientation
ROOF CONSTRUCTION
Traditional method was to lay closely spaced timber beams and cover them with a layer of reed or grass matting and a thick layer (0.45. to 0.6m) of earth on top. Because of the difficulty of finding timber in the desert, later in some housed timber was replaced by stone slabs. In all cases the roof and the floor was finished only with mud plaster. The roofs were very thick to avoid the penetration of harsh sunlight into the building. And all the buildings had flat roofs so that rainwater harvesting can be practised as the region receives very less rainfall throughout the year.
The natural cooling systems used at Jaisalmer include: ➢ Dense clustering of building. ➢ Sun control through orientation and structural projections. ➢ Cooling of surfaces by use of fins. ➢ Massive construction for roofs and walls. ➢ Courtyards and other air ducts for ventilation.
Rethinking tradition: Passive housing in the desert, Jaisalmer, Rajasthan, India.
CLIMATE RESPONSIVE ARCHITECTURE
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ARCHANA PRASAD Prasad Archana USN 01FA16BAT013 USN 01FA16BAT013 SEMESTER 3 Semester – 3 KLETU
KLETU
STUDIOS 18 / SANJAY PURI ARCHITECTS In response to hot arid climate prevalent in the location of 8 months of summer and LOCATION : RAS, RAJASTHAN temperatures in excess of 35 degree C, the apartments are all oriented towards the north, north-east and north-west with no apartment facing the south. The low rise design allows the residents of studios 18 to be close to the ground level akin to living in individual houses.
The linear corridors provide a cool ventilated sheltered walkway between the apartments allowing the residents to glimpse landscaped spaces on either side while walking through and making the circulation an interesting experience. Each apartment too is cross ventilated with deep recessed windows and open to sky terraces.
Situated on undulating site in the deserts of Ras, Studios 18 Apartments are a part of an entire layout spread over 36 acres. Taking a cue from the organic layouts of the neighbouring villages near the site, the residential units are interspersed within the existing contours along organic streets that weave through the site.
The apartments follow the organic nature of old Indian cities with houses stepping back and creating interlocked built volumes across three levels.
Rethinking tradition: Passive
Most cities in Rajasthan state are identified by a colour. Jaisalmer is known as the yellow city for its traditional houses being built in yellow The circulation spaces connecting the house sandstone. The colour palette used is the most significant part of its Colour acts as an integral parameter in blocks are naturally ventilated with an abstract visual impact. The deconstructed cubes sport varied hues of the sandy composition of square punctures on either side differentiating volumes as well as identifying region, at different times of the day – visually differentiating the stepped, facilitating air to move through. The harsh glare circulation spaces interestingly while alluding to recessed volumes as well as identifying circulation spaces. With lighter the colours of the region. In Rajasthan colour of the sun is cut off; yet allowing natural light hues on external walls to reflect heat off the surfaces, and darker tones within the linear corridors, and creating different plays an important role in the lives of the people indoors to create a cooler feel, they add impact to the highly who wear bright colours daily. patterns at different times of the day. ‘responsive’ design solution. SHEET NO. ARCHANA PRASAD Prasad SHEET NO. Archana USN 01FA16BAT013 housing in the desert, Jaisalmer, Rajasthan, India. USN 01FA16BAT013 SEMESTER 3 Semester – 3 KLETU KLETU
CLIMATE RESPONSIVE ARCHITECTURE
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Built form, materials and design principles has played has played a decisive role in providing comfortable conditions against the adversities of prevailing climatic conditions.
Rethinking tradition: Passive housing in the desert, Jaisalmer, Rajasthan, India.
CLIMATE RESPONSIVE ARCHITECTURE
Studios 18 has contextually designed housing project that is sustainable by its design adhering to the existing contours, its orientation to reduce heat gain, its facilitation of natural light and ventilation and its low rise design. SHEET NO. SHEET NO.
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ARCHANA PRASAD Prasad Archana USN 01FA16BAT013 USN 01FA16BAT013 SEMESTER 3 Semester – 3 KLETU
KLETU
DESIGN CONSIDERATIONS ➢ Landscape features should be added to protect the building from harsh strong and dry winds. ➢ The control of microclimate can be achieved by clustering. Clustering prevents heat gain, ensures movement of cooler air through the building and open courtyards. ➢ The design should incorporate courtyards so that the air circulates among the cool shaded surfaces. ➢ Horizontal overhangs / projections should be installed as they control the internal climate of the courtyard efficiently by controlling the quality of light, wind circulation and angle of sunlight on surfaces. ➢ The roofs should be thick enough to be able to withstand the incident solar radiation.
➢ Carving the building facade exposed to sun also helps in cooling the wall faster as it increases the heat transfer to the air. These rough surfaces create internal granular shading and are more beneficial than smooth surface even with lighter colour. ➢ The site can have water body to increase the humidity. ➢ The building can be compartmentalized so that minimum sunlight reaches the interior and zoning of the areas can be done accordingly by placing the most utilized area in the interior and giving corridors, verandah or balconies in the exterior parts of the building. The building envelope can have openings or perforated walls and the interior roos can have comparatively smaller openings; thus increasing wind
Rethinking tradition: Passive housing in the desert, Jaisalmer, Rajasthan, India.
CLIMATE RESPONSIVE ARCHITECTURE
speed in the building. ➢ The width between two building should be one-third (or less) of the height of the buildings. ➢ A cantilevered structure is preferable in a place like Jaisalmer. ➢ Air ducts on the either side of the building and courtyard at the centre and creating the “courtyard effect” is the ideal way of dealing with the climatic issues. ➢ The building should have flat roof so that rainwater harvesting can be practised. ➢ Interconnected vertical shafts can be used for ventilation. ➢ Staircases can also acts as the vertical shafts in the design. SHEET NO. SHEET NO.
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ARCHANA PRASAD Prasad Archana USN 01FA16BAT013 USN 01FA16BAT013 SEMESTER 3 Semester – 3 KLETU
KLETU