Architecture Research

Ankita Arora School of Architecture, IPS Academy, Indore, Madhya Pradesh, India

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CONTENTS CONTENT NO.

TITLE

PAGE NO.

1. Introduction…………………………………………………..………..10 1.1 Need and concern of the topic 1.2 Aim 1.3 Objective 1.4 Scope and Importance 1.5 Limitations 2. Understanding the context………………………………………....13 2.1 Historical Background 2.2 Geography 2.3 Climate 2.4 Cities of Rajasthan 3. Introduction to Hot and Dry Climate……………………….……..22 3.1 Climatic Parameters 3.2 Methods to reduce heat gain in building 3.3 Factors of human comfort 3.4 Critical issues of the parameters 4. Settlement pattern of RajasthanA historical perspective………………………………………….…..25 4.1 Jaisalmer 4.1.1 City level 4.1.1.1

Historical Background

4.1.1.2

Architecture

4.1.1.3

Response to climate

4.1.2 Neighbourhood level 4.1.3 Cluster 4.2 Jodhpur 4.2.1 City Level

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4.2.1.1

Historical Background

4.2.1.2

Architecture

4.2.1.3

Response to climate

4.2.2 Cluster 4.3 Nagaur 4.3.1 City Level 4.3.1.1

Historical Background

4.3.1.2

Architecture

4.3.1.3

Response to climate

5. Case Studies (Dwellings)…………………………………………..….51 6. Introduction

to

building

problems

in

hot

and

dry

climate…………...78 7. Techniques for controlling temperature, wind and glare in Rajasthan……………………………………………………….…….79 7.1 Temperature control 7.1.1 Orientation 7.1.2 Built Form 7.1.3 Building Envelope 7.1.3.1

Roofs

7.1.3.2

Walls

7.1.4 Shading Devices 7.1.4.1

Shading through texture on walls

7.1.4.2

Shading devices

7.1.5 Open Spaces 7.1.5.1

Courtyard

7.1.5.2

Outdoor Spaces

7.2 Wind Control (outdoors) 7.2.1 Plan Form 7.2.2 Surrounding Landscape 7.2.2.1

Landform

7.2.2.2

Vegetation

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7.2.3 Wind Catcher 7.2.4 Openings 7.3 Glare 7.3.1 Albedo 8. Summary……………………………………………………………….96 9. Conclusion……………………………………………………………..98 10. Bibliography……………………………………………………..…...102 11. Webliography………………………………………………….…….103 12. Glossary………………………………………………………………..104 13. Appendices…………………………………………………….…….106

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LIST OF TABLES TABLE NO.

TITLE

PAGE NO.

1. Table 1- Climatic features for hot and dry climate………….……23 2. Table 2 -Critical Parameters and Human Comfort………….……24 3. Table 3-Percentage of openings to floor of Jaisalmer Haveli……………………………………………………………….…..….51 4. Table 4-Mapping of climatic elements v/s design parameters…………………………………………………………….....52 5. Table 5-Mapping of climatic elements v/s design parameters of Roopsi House, Jaisalmer……………………...…….55 6. Table 6- Percentage of openings to floor of Haveli 2…………....58 7. Table 7-Mapping of climatic elements v/s design parameters of Haveli 2, Jaisalmer…………………………………...59 8. Table 8- Mapping of climatic elements v/s design parameters of a house in mathuron ki pol, Jodhpur……….……64 9. Table 9-Mapping of climatic elements v/s design parameters of a haveli in Jodhpur……………………………….....67 10. Table 10- Mapping of climatic elements v/s design parameters of Palana district, Bikaner………………………..…...70 11. Table 11- Mapping of climatic elements v/s design parameters of Tejiavyas district, Barmer……………………….......73 12. Table 12- Techniques used in the case studies…………………...75 13. Table 13-Summary showing the materials and techniques used in the case studies…………………………….....76 14. Table 14- Merits and demerits of forms: Urban level………….....80 15. Table 15-Merits and demerits of forms: Rural level……………….81 16. Table 16-Techniques for lowering down the temperature through roof………………………………………………………….....85 17. Table 17- Merits and demerits of techniques for walls………….87

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18. Table 18- Merits and of shading on walls through texture………88 19. Table 19- Merits and demerits of shading devices…………….…89 20. Table 20- Merits and demerits of courtyard………………………..90 21. Table 21- Merits and demerits of street layouts……………………92 22. Table 22-Merits and demerits of plan form………………………...92 23. Table 23- Merits of landform…………………………………….….…93 24. Table 24- Merits and demerits of vegetation in controlling wind…………………………………………………….……93 25. Table 25- Merits and demerits of wind catcher……………………93 26. Table 26-Merits of openings…………………………………………...94 27. Table 27- Albedo values of certain materials……………………...94 28. Table 28- Role of an Architect in providing comfortable indoor environment…………………………….……...98 29. Table number 29-Comfort requirements and physical manifestation………………………………………………....99

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LIST OF FIGURES Figure No.

Title

Page No.

1. Figure 1: A courtyard of a house in Rajasthan…………….11 2. Figure 2: A façade of a building in Rajasthan……………..11 3. Figure 3 - World Map showing location of Rajasthan……13 4. Figure 4 - India map showing Rajasthan…………………...14 5. Figure 5- Map of India showing climatic zones with climatic classification of Rajasthan (Based on Rainfall Distribution)……………………………....19 6. Figure 6 – Jaisalmer city………………………………………..20 7. Figure 7–Jodhpur city…………………………………………..20 8. Figure 8– Nagaur city…………………………………………...21 9. Figure 9- Bioclimatic Chart…………………………………....22 10. Figure 10- Spatial zoning of Jaisalmer…………………...….25 11. Figure 11- Façade of Jaisalmer ‘haveli’…………………....26 12. Figure 12- Jaisalmer city built entirely of yellow sandstone………………………………………………..27 13. Figure 13- Section showing carved elements on the streets of Jaisalmer…………………………………...28 14. Figure 14- Schematic plan of the central area of Jaisalmer……………………………………………….29 15. Figure 15- Street elevation…………………………………....29 16. Figure 16(a), (b) Streets of Jaisalmer…………………….....30 17. Figure 17- A façade of Jaisalmer.…………………………...30 18. Figure 18-House form- Small houses………………………...31 19. Figure 19-House form- Middle income people………………………………………………....31 20. Figure 20-House form- Haveli……………………………..….32 21. Figure 21- Schematic sketch of orientation of streets and direction of wind storms………………..……32 22. Figure 22-Street section of Jaisalmer……………………......33 23. Street section of Jaisalmer……………………………...…..…33 24. Figure 24-Town plan of Jaisalmer city……………………….33 25. Figure 25-Neighbourhood plan of Jaisalmer city………………………………………………….....34

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26. Figure 26- West elevation of the street…………………...…35 27. Figure 27-Plan of a Jaisalmer cluster………………………...36 28. Figure 28-Schematic section of the street in the cluster………………………………………………37 29. Figure 29-Schematic section showing heat ingress inside a building …………………………………..…..37 30. Figure 30- Shadow analysis of Jaisalmer cluster from 7:00 A.M. to 12:00 P.M……………………………….…38 31. Figure 31- Shadow analysis of Jaisalmer cluster from 1:00 P.M. to 06:00 P.M ………………………...39 32. Figure 32-Narrow compact streets, with fairly high buildings provide shade ………………………………..39 33. Figure 33- Schematic plan of Jodhpur……………………..40 34. Figure 34- Built Forms in Jodhpur………………………….…42 35. Figure 35-Fort overlooking the blue city of Jodhpur……………………………………………………….43 36. Figure 36- Town Plan of Jodhpur…………………………….44 37. Figure 37- Cluster1: Jodhpur……………………………….…45 38. Figure 38- Cluster 2: Jodhpur…………………………….…...46 39. Figure 39-Shadow analysis of cluster of Jodhpur from morning 6:00 A.M. to 2:00 P.M……….…..…46 40. Figure 40-Shadow analysis of cluster of Jodhpur from morning 3:00 P.M. to 6:00 P.M………….…..47 41. Figure 41- Street section: Jodhpur………………………….......47 42. Figure 42-Schematic town plan of Nagaur…………………...48 43. Figure 43-Town plan of Nagaur……………………………........49 44. Figure 44: Plan and section of Haveli 1 of Jaisalmer………..50 45. Figure 45-Plan and section of Roopsi house, Jaisalmer……………………………………………..........54 46. Figure 46- Plan and section of Haveli 2………………………..56 47. Figure 47- Plan and section of Patwa Haveli…………………60 48. Figure 48-Plan of a house in Mathuron ki Pol, Jodhpur………………………………………………………62

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49. Figure 49 Plan and section of a haveli in Jodhpur…………..65 50. Figure 50-Plan and section of a house in Palana district…………………………………………………….68 51. Figure 51- Plan and section of a house in Tejiavas, Barmer………………………………………………… 71 52. Figure 52-Stack effect of courtyard in day and nightimr…..74 53. Figure 53- Gradations of light and heat in verandahs next to courtyard………………………………....74 54. Figure 54- Showing shading by jharookhas in the havelis………………………………………………………...74 55. Figure 55- Section of Jharookha…………………………….......74 56. Figure 56-Section showing the street and carved façade of the building……………………………….....74 57. Figure 57- Detail of a building façade…………………………74 58. Figure 58-Stone wall………………………………………………..75 59. Figure 59- Mud wall………………………………………………...75 60. Figure 60-Section of a shading device above window……………………………………………………...75 61. Figure 61- Schematic section of Jaali…………………………..75 62. Figure 62- Solar radiation on sides of the building………..….78 63. Figure 63- Building orientation…………………………………...79 64. Figure 64-The surface area to volume ratio of various building layouts………………………………...............79 65. Figure 65- Cube…………………………………………….….…..80 66. Figure 66- Cuboid………………………………………………....80 67. Figure 67-Cylinder………………………………………….….…..81 68. Figure 68-Cone…………………………………………………….82 69. Figure 69-Double roof…………………………………………....82 70. Figure 70-Section of roof ponds (a) Summer; (b) Winter…………………………………….….…83 71. Figure 71- Inclined roof……………………………………...…...83 72. Figure 72- Section showing reflective roof surface……………………………………………….……….83 73. Figure 73- Section showing inverted earthen pots…….…..84 74. Figure 74- Domical roof……………………………………..…..84 75. Figure 75- Section showing plant cover on roof………..….85 76. Figure 76-Solid Wall: Brick…………………………………….…85 77. Figure 77-Solid Wall: Stone……………………………..………86 78. Figure 78- Section showing cavity wall………………….…..86 79. Figure 79- Section showing mud wall…………………..……87

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80. Figure 80- Section showing lime plastered brick wall………………………………………………………….87 81. Figure 81-Shading by texture on walls……………………...88 82. Figure 82- Horizontal Shading Device………………………89 83. Figure 83- Vertical Shading Device…………………………89 84. Figure 84- Egg-crate shading Device…………………..…..89 85. Figure 85-Courtyard effect……………………………….…...90 86. Figure 86- Street: Grid diagonal to east-west axis…….…..90 87. Figure 87-Section showing shading on the street…….......90 88. Figure 88- Zigzagging alleys………………………………......91 89. Figure 89-Blocked streets………………………………….…...91 90. Figure 90- Circular Planform……………………………….....92 91. Figure 91-Square planform……………………………….….92 92. Figure 92-Landform …………………………………………...93 93. Figure 93- Vegetation helping in lowering down the temperature……………………………………….93 94. Figure 94-Working of wind tower………………………..….93 95. Figure 95- Section showing jaali…………………….……....94

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1. INTRODUCTION

Rajasthan is indeed the most colourful state in India. It has a unique architecture and is renowned for it all over the world. The stupendous

forts,

the

intricately

carved

temples

and

the

grand ‘havelis’ of the state are integral parts of the architectural heritage of the state. The Rajputs were prolific builders. Some of the most imposing and magnificent forts and palaces in the world dot the arid Aravali landscape and tell the tales of their glorious legacy.

Rajasthan having mostly hot-dry climate zone & partly composite climate zone needs to have an integrated approach towards planning & designing of affordable, sustainable & eco-friendly buildings.

Climate is an important aspect of life particularly in areas with hot and dry climate such as Rajasthan, where people face variety of problems related to climate especially in housing. Traditional built environment of Rajasthan is considered appropriate for both the climate as well as for social conditions. The modern architecture of international style which has dominated the new developments generally considered inappropriate,

particularly

because

it

was

introduced

without

consideration for the local climate or for the cultural need of the population.

Traditional built environment in Rajasthan have evolved in response to climate, reducing the effect of hostile desert climate conditions. To modify extremes of air temperature, and to protect the inhabitants from solar radiation and glare as well as from sand and dust.

In hot and dry climate the most significant problems are those caused by solar radiation and UV rays. Thus a need for eco-friendly building materials and climate responsive techniques are to be adopted for comfortable indoor environment.

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Figure 1: A courtyard of a house in Rajasthan

Figure 2: A façade of a building in Rajasthan

1.1 Need and concern for the topic Energy use being the number one contributor to global warming, an obvious way to mitigate climate change is to design low or no-energy use buildings.

To do so means going back to basics and looking carefully at how the design of a building is optimized to the particular features of a specific site in order to minimize the potential of extreme energy use.

Climate is an important aspect of life particularly in areas with hot and dry climate such as Rajasthan, where people face variety of problems related to climate especially in housing.

The great temperature difference of 45°C in summer and cold winter

nights

with

temperature

below

freezing

point,

impose

considerable strain on the construction and material in the form of swelling and contraction. Sand bearing winds have a damaging effect on the surface finishes, such as sand blasting surfaces. Although the choice of the building material is essentially determined by local availability, their economy, durability and suitability for the particular climate.

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The main concern arises to modify extremes of air temperature, and to protect the inhabitants from solar radiation and glare.

1.2

Aim

1. To analyse the architectural design of the individual dwelling units

as manifestation of various techniques with respect to climate.

2. To understand the spatial planning parameters of various macro

and micro settlements climatically.

1.3

Objective

 To find out the morphological growth pattern of the settlement,  To understand the Climatic planning pattern of the settlement,



To analyse the architectural design of the individual dwelling units as manifestation of various design parameters, such as local climate conditions,



To find out the architectural details of various building elements, motifs, symbols, etc., used by them to build climate responsive city.

 Study of climate responsive materials, their properties and coordination with respect to the local climate.

 Study of precedents in the genre  Literature study of ancient forts (materials, heat control) 1.4 Scope & Importance 

Prevailing climatic techniques in Rajasthan.



Building in response to climate and reducing the impact of heat.



Basic fundamental factors behind climatic designing.



General techniques involved in reducing heat gain inside the building.

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1.5 Limitations 

The study area would remain to Rajasthan and all the techniques that have been observed in the state.



The study would be limited to architectural aspects of building construction and not structural/mechanical aspects.

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2. UNDERSTANDING THE CONTEXT

Figure 3 - World Map showing location of Rajasthan

Rajasthan



Area 342,236 km² (132,138 sq mi)



Capital: Jaipur



Largest city: Jaipur



Districts: 32



Population approximately: 58 million



Language(s) : Hindi, Rajasthani

Mother

India, the vast Subcontinent constituting the world's

largest democracy, an intriguingly complex religious and cultural tapestry with her great mercantile classes, sprawling bureaucracies and exploding economy, remains one of the most visually memorable and bewitching journeys ever.

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Of all her states, Rajasthan is perhaps the most tribally diverse, artistically decorative, architecturally magnificent and regal in India. It is impossible to experience and absorb in a single trip the magnitude of what India offers: 

The incredible light,



The austere and atmospheric landscapes of desert and ancient Aravali mountains,



The romance of Rajasthan’s heritage and chivalry,



The hospitality and humor of the people whether from regal lineage or simple,



Dignified desert-dwellers, and their arts and crafts.

2.1 Historical Background The history of the Indian state of Rajasthan is about 5000 years old. The history of Rajasthan can be classified into three parts owing to the different epochs- Ancient, Medieval and Modern.

Ancient Period, up to 1200 AD Rajput clans emerged and held their sway over different parts of Rajasthan from about 700 AD.

Figure 4 - India map showing Rajasthan

Before that, Rajasthan was a part of several republics. It was a part of the Mauryan Empire. Other major republics that dominated this region include the Malavas, Arjunyas, Yaudhyas, Kushans, Saka Satraps, Guptas and Hunas.

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The Rajput clans ascendancy in Indian history was during the period from the eighth to the twelfth century AD. The Pratihars ruled Rajasthan and most of northern India during 750-1000 AD. Between 1000-1200 AD, Rajasthan witnessed the struggle for supremacy between Chalukyas, Parmars and Chauhans.

Medieval Period, 1201 - 1707 Around 1200 AD a part of Rajasthan came under Muslim rulers. The principal centers of their powers were Nagaur and Ajmer. Ranthambore was also under their suzerainty. At the beginning of the 13th century AD, the most prominent and powerful state of Rajasthan was Mewar.

Modern Period, 1707 - 1947 Rajasthan had never been united politically until its domination by Mughal Emperor - Akbar. Akbar created a unified province of Rajasthan.

Mughal power started to decline after 1707. The political disintegration of Rajasthan was caused by the dismemberment of the Mughal Empire.

The Marathas penetrated Rajasthan upon the decline of the Mughal Empire. In 1755 they occupied Ajmer. The beginning of the 19th Century was marked by the onslaught of the Pindaris.1

2.2 Geography Rajasthan is the largest state of the Republic of India in terms of area. It encompasses most of the area of the large, inhospitable Great Indian Desert (Thar Desert), which has an edge paralleling the SutlejIndus river valley along its border with Pakistan. The region borders Pakistan to the west, Gujarat to the southwest, Madhya Pradesh to the southeast, Uttar Pradesh and Haryana to the northeast and Punjab to the north. Rajasthan covers an area of 342,239 km² (132,139 mi²).

1

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The Thar Desert covers the western half of Rajasthan. The main geographic features of Rajasthan are the Thar Desert and the Aravalli Range, which runs through the state from southwest to northeast, almost from one end to the other, for more than 850 km. Mount Abu is at the southwestern end of the range, separated from the main ranges by the West Banas River, although a series of broken ridges continues into Haryana in the direction of Delhi where it can be seen as outcrops in the form of the Raisina Hill and the ridges farther north. About three-fifths of Rajasthan lies northwest of the Aravallis, leaving two-fifths on the east and south.

The northwestern portion of Rajasthan is generally sandy and dry.

Most of the region is covered by the Thar Desert, which extends into adjoining portions of Pakistan. The Aravalli Range intercepts the moisture-giving southwest monsoon winds off the Arabian Sea, leaving the northwestern region in a rain shadow. The Thar Desert is thinly populated; the town of Bikaner is the largest city in the desert. The Northwestern thorn scrub forests lie in a band around the Thar Desert, between the desert and the Aravallis.

The Godwar, Marwar, and Shekhawati regions lie in the thorn scrub forest zone, along with the city of Jodhpur. The Luni River and its tributaries are the major river system of Godwar and Marwar regions, draining the western slopes of the Aravallis and emptying southwest into the great Rann of Kutch wetland in neighboring Gujarat. This river is saline in the lower reaches and remains potable only up to Balotara in Barmer district. The Ghaggar River, which originates in Haryana, is an intermittent stream that disappears into the sands of the Thar Desert in the northern corner of the state and is seen as a remnant of the primitive Saraswati River.

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The Aravalli Range adds diversity to the landscape of Rajasthan.

The Aravalli Range and the lands to the east and southeast of the range are generally more fertile and better watered. The hilly Vagad region lies in southernmost Rajasthan, on the border with Gujarat. With the exception of Mount Abu, Vagad is the wettest region in Rajasthan, and the most heavily forested. North of Vagad lies the Mewar region, home to the cities of Udaipur and Chittaurgarh. The Hadoti region lies to the southeast, on the border with Madhya Pradesh. North of Hadoti and Mewar is the Dhundhar region, home to the state capital of Jaipur.

Mewat, the easternmost region of Rajasthan, borders Haryana and Uttar Pradesh. Eastern and southeastern Rajasthan is drained by the Banas and Chambal rivers, tributaries of the Ganges.

The Aravalli Range runs across the state from the southwest peak Guru Shikhar (Mount Abu), which is 1,722 m in height, to Khetri in the northeast. This divides the state into 60% in the northwest of the range and 40% in the southeast. The northwest tract is sandy and unproductive with little water but improves gradually from desert land in the far west and northwest to comparatively fertile and habitable land towards the east. The area includes the Thar Desert. The south-eastern area, higher in elevation (100 to 350 m above sea level) and more fertile, has a very diversified topography. In the south lies the hilly tract of Mewar. In the southeast, a large area within the districts of Kota and Bundi forms a tableland. To the northeast of these districts is a rugged region (badlands) following the line of the Chambal River. Farther north the country levels out; the flat plains of the northeastern Bharatpur district are part of an alluvial basin.2

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2.3 Climate The climate of Rajasthan state has varied contrasts and the presence of Aravallis is the greatest influencing factor. The state can broadly be divided into Arid, Semi-Arid and Sub-Humid Regions, on the basis of rainfall intensities. The Western Rajasthan i.e. in the arid region consist of the districts of Hanumangarh, Jaisalmer, Barmer, Ganganagar, Churu, Jhunjhunu, Sikar, Nagaur, Jodhpur, Pali and Jalore covering an area of nearly 1,43,842 sq.km. The region is characterized by low and highly variable rainfall years creating inhospitable living condition to both human and livestock population. An area of 9,290 sq km in extreme western parts of the state has true desert conditions. With an improvement in rainfall pattern from the west towards the east Rajasthan semi-arid conditions are created in an area of about 66,830 sq km in the districts of Alwar, Jaipur, Bharatpur, Ajmer, Tonk, Sawai Madhopur, Bhilwara, Bundi, Kota, Chittorgarh, Udaipur, Sirohi, Dungarpur and parts of Jhalawar and Banswara. The distribution of climatic regions of Rajasthan on the basis of rainfall and temperature variations is divided into the following categories: (1) Arid Region: The Arid region includes Jaisalmer district, northern parts of Barmer, western of the Phalodi Tehsil of Jodhpur, western parts of Bikaner and southern parts of Ganganagar district.

Climate of the region is very severe and arid. Rainfall less than 10 cm in extreme west parts of regions and rest areas record less than 20 cm rainfall. The average temperature during summer is recorded more than 34°C and during winters it ranges in between 12° C to 16° C. (2) Semi-arid Region: The average temperature during winter season ranges between 10° C and 17° C and the summer season temperature range 32° C to 36° C. As the region has erratic as well

20

as torrential rainfall it brings floods too each time. Rainfall ranges 20 to 40 cm. This region comprises the western parts of Ganganagar, Hanumangarh, Jodhpur and Barmer districts. The winter season is very short and arid in the northern parts of this region.

(3) Sub-humid Region: In the semi arid humid region, rainfall is meager and the amount of rainfall is limited to a few monsoon months only. The rainfall is between 40 to 60 cm and the average temperature during summer season ranges from 28째 to 34째 C whereas it is recorded 12째 C in northern parts and 18째 C in the southern parts. Alwar, Jaipur, Dausa and Ajmer, eastern parts of Jhunjhunu, Sikar, Pali and Jalore districts, north-western parts of Tonk, Bhilwara and Sirohi districts are included in this category. This region has steppe type of vegetation.

(4) Humid Region: this region receives winter rainfall associated with cyclones along with monsoon season rainfall which varies from 60 to 80 cm. Deciduous trees dominate the region. Humid region is found at the districts of Bharatpur, Dholpur, Sawai Madhopur, Bundi, Kota, Barmer and Rajsamand and the north-eastern parts of Udaipur.

(5) Very Humid Region: Very Humid Region includes south-east Kota, Baran, Jhalawar, Banswara, south-west Udaipur and adjacent areas of Mt. Abu. Here, the summers are very hot and winters are cold and dry. Rainfall received is between 80 cm to 150 cm, which is mostly during the rainy season. Monsoon savanna type of vegetation is present in the region3

3

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21

Figure 5- Map of India showing climatic zones with climate classification of Rajasthan (based on rainfall distribution) (Source: Energy Conservation Code, 2007; Source: Contemporary Rajasthan, 2009, by L.R. Bhalla)

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2.4 Cities of Rajasthan 1. Jaisalmer: A city in the Indian state of Rajasthan, located 575 kilometres west of the state capital Jaipur. The town stands on a ridge of yellowish sandstone, crowned by a fort, which contains the palace and several ornate Jain temples.

Many of the houses and temples are finely sculptured. It lies in the heart of the Thar Desert (the Great Indian Desert) and has a population of about 78,000. Jaisalmer, being an arid desert region, is prone to extremes

Figure 6 – Jaisalmer city

in terms of temperature.

2. Jodhpur:

The

second

the Indian state of Rajasthan and

largest officially

city the

in second

metropolitan city of the state. The city is known as the "Sun City" for the bright and sunny weather it enjoys all the year round. The old city circles the fort and is bounded by a wall with several gates.

Jodhpur is also known as the "Blue City" because of the blue colours that decorate many of the houses in the old city area. The climate of Jodhpur is hot and semiarid during its nearly yearlong dry season, but contains a brief rainy season from late June to September (KĂśppen BSh).1

Figure 7–Jodhpur city

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3. Nagaur: The ancient city of Nagaur in the Marwar region of central Rajasthan was one of the first strongholds of Muslim power (12th– 16th century) in northern India.

The

district

lies

in

the Marwar region

of

Rajasthan,

in

the Northwestern thorn scrub forests belt

surrounding

the Thar Desert. Nagaur has a tropical

desert

climate,

Figure 8– Nagaur city

extremely cold from October to February and scorching hot 4. Barmer: A todistrict in Rajasthan state of India. It is located in the from March September. western part of Rajasthan state forming a part of the Thar Desert.

Partially being a desert, this district has a large variation in temperature.

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3. INTRODUCTION TO HOT AND DRY CLIMATE 3.1 Climatic Parameters CLIMATIC

SITUATION IN HOT AND GENERIC

PARAMETERS

DRY CLIMATE

CORRESPONDING STRATEGY

Typical landscape Sandy/rocky ground with -Preserve vegetation and vegetation

little vegetation

and conserve water

Low water level Solar Radiation

Intense (800-950 W/m)

-Shade building especially openings as they admit maximum solar radiation Solar energy generation

Summer midday

40º - 45º C

Mean

Summer

temperature

night Winter midday

20º - 30º C

5º - 25º C

- Prevent solar access in summer but allow in winters - Insulate building to prevent conduction of heat indoors during the day time - Passive measures to reduce heat gain and promote heat loss through vegetation & water bodies.

- Prevent solar access in summer but allow in winters - Insulate building to prevent

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Winter

0º - 10º C

night Diurnal variations

Mean relative humidity

15 - 20º C

Very low (25%- 40%)

conduction of heat indoors during the day time - Passive measures to reduce heat gain and promote heat loss through vegetation & water bodies.

-Can use evaporative cooling where water is available

Annual rainfall

Low < 500mm / year

-Harvest rainwater for use in dry spells

Winds

Dust laden local winds often developing into sandstorms

-Prevent wind infi ltration; Avoid wind-induced ventilation during overheated times

Sky conditions

Cloudless skies with high solar radiation causing glare

-Prevent direct radiation ingress and glare into rooms

Table 1- Climatic features for hot and dry climate (Source: CPWD- Integrated Green Design for rural and urban buildings in Hot and dry climatic zones)

3.2 Methods to reduce heat gain in hot and dry climate Various Methods to reduce heat gain in a building 

Building orientation



Building surface cooling



Shading by neighbouring



Roof ponds and garden

buildings



Solar chimney



Shading by vegetation



Courtyard effect



Reflecting surfaces



Air vent and wind tower

26



Sensible and evaporative



Air cooling by tunnels

cooling



Thermal storage

3.3 Factors of human comfort The comfort zone is established by analysing the relationship between air temperature and three climatic variables: 

Mean radiant temperature

Figure 9- Bioclimatic Chart

(the temperature of the surrounding surfaces)  

Humidity

Temperature

Physiological indoor comfort in summer under still- air conditions (rooms with closed windows), for persons acclimatized to hot-dry climate, can be maintained as long as the indoor temperature is kept below 27° -28° C (80.6-82.4 F). This seemingly high comfort limit is possible in desert regions because discomfort due to clamminess and wet skin is minimized by the low humidity. 4 Parameters

Climatic

Human comfort

features Maximum

day

time

summer 45°C

32° C

temperature Relative humidity

20%

25 - 60%

Table 2 -Critical Parameters and Human Comfort

4

Baruch, Givoni; Climate considerations in building and urban design, 1998

27

3.4 Critical issues of the parameters 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 â&#x20AC;&#x153;water bodiesâ&#x20AC;? is desirable as they can help increase the humidity, thereby leading to lower air temperatures. The ground and surrounding objects emit a lot of heat in the afternoons and evenings. As far as possible, this heat should be avoided by appropriate design features.

28

4. SETTLEMENT PATTERN OF RAJASTHAN- A HISTORICAL PERSPECTIVE 4.1 Jaisalmer 4.1.1 City Level 4.1.1.1 Historical Background

In the year 1156 AD, the place Jaisalmer was established by Maharawal Jaisal. The word “Jaisalmer" means the Hill Fort of Jaisal.

Because the yellow sandstone and the yellow sand used in almost in all architecture of the city, it is also called as “The Golden City”. In 1293, the Bhattis so infuriated the king Ala-ud-din Khilji that his army sacked the fort and city of Jaisalmer, for this reason the place was deserted for quite some time. Many Bhatti's from the Royal family shifted to Jaisal which falls under Pakistan now and some moved to Talwandi which falls under Nankana Sahib Distt. The major enemies of the Bhati Rajputs were the influential and powerful Rathor family of Bikaner and Jodhpur. Jaisalmer was one of the last states to sign an agreement with the British 5.

4.1.1.2 Architecture Jaisalmer developed into one of the most interesting cities dominated by the trading

community.

Compactly

built

entirely of stone, on top of a hillock and its Figure 11- Spatial zoning of Jaisalmer

5

http://www.discoveredindia.com/rajasthan/culture-in-rajasthan/architecture-in-rajasthan.htm

29

slopes with nothing else in the vicinity, the city gives little sense of scale when viewed from a distance. One feels that the city is a piece of sculpture carved out of solid stone rather than constructed piece by piece. It has many tall buildings, upto seven storeys high, giving it a vertical effect.

Figure 11- Façade of Jaisalmer â&#x20AC;&#x2DC;haveliâ&#x20AC;&#x2122;

Cluster Cluster space is quite frequently found, particularly in the upper city. It is either a space which connects streets on two or four sides or it is made by widening a street at a particular point. In any case, each space serves a group of houses for their immediate activities.

The architecture of the city displays a strong sense of anonymity which is essentially a cultural trait. In some of the oriental cultures it is a part of life and comes naturally to people. This found expression, especially, in domestic architecture. The spaces acquire non- specific character. They change in their use as the morning changes into noon and noon changes into evening. They are also used differently in summer and winter. Interior open spaces like courtyards, terraces and balconies have special significance under such situations. They accommodate a variety of activities during different seasons or different parts of the day.

30

Grown out of a modulation at the domestic scale, dictated by the limitation of stone construction, the town presents a picture of unique order. Yet, it is not regimented. The smallest house is generally a two bay house with one of the bays having the courtyard. It is the number of bays that increase as the houses become larger. The houses built on the periphery of the upper as well as the lower city show some differences in character. There are major streets oriented almost E-W and minor streets at right angles to these. The famous decorative house-fronts are located mainly on the E-W streets which are relatively wider, the height of the buildings being one to two times the width of the street. The N-S streets, on the other hand, are only about one fourth the height of the buildings on the sides.

An aerial view of the city gives an impression of cubical grains arranged in close proximity. Courts and terraces expose the sides of these grains. Though very solid looking, the city has porosity, somewhat comparable to a honeycomb due to a certain uniformity and fineness of the textural quality. This is because of the constancy of building modules used.

Figure 12- Jaisalmer city built entirely of yellow sandstone

Streets of Jaisalmer Jaisalmer is a compact network of short streets. In negotiating the terrain, the streets have become quite interesting. With fairly high buildings and the streets rarely more than four meters wide and the latter

31

are almost always in cool shade. There is some difference in the street pattern of the upper and lower city though the general ambience is similar. The radial pattern found above is contrasted by the grid iron pattern in the city below, though the streets do not run in exact straight lines nor do they meet at right angles.

Location of certain squares in strategic places along with a welldeveloped and definite order of streets and buildings makes the city well organized. The major part of the lower city is divided into somewhat rectangular blocks with closely built buildings. These blocks show continuous facades of exquisitely carved elements behind which are the open courts and terraces making them fairly porous in plan. Streets have at times strong pauses but, are on the whole modulated with subtle curves enhancing the view of the richly ornamented buildings; at the same time not exposing the entire view of the facades all at once. In general, the variations for any hierarchical order are too little to be of any consequence.

Figure 13- Section showing carved elements on the streets of Jaisalmer (Image source: https://architexturez.net/doc/az-cf-123687)

Jaisalmer streets are more than mere paths- they are public spaces too. Although they harbour activities which are comparable to cluster spaces, the street as a space has a different character. Not only is the composition more linear, it is also limited in terms of activities. ď&#x201A;ˇ

Narrow winding streets with densely built construction on both sides.

32



All major streets were oriented in the east-west direction at right angles to the direction of dust storms.



The height of the building compared to the width of streets is large to create shaded cool environment for the pedestrian and other social activities on the streets.



The street orientation ensures that the building facades are either shaded by jharokhas or chajjas projections.



An e-w street orientation, in summer the sun would be shining on the south facade from 9.30am

to

2.30pm. 

The corresponding solar altitudes during this time are 54° to 86° and even small horizontal projections are sufficient to shade the southfacing building.



Figure 14- Schematic plan of the central area of Jaisalmer

The north face of the building

(Image source: Gupta, Vinod; Natural

receives solar radiation before 8 am

Cooling Systems of Jaisalmer

and after 4pm with solar altitude

Assistant Professor of Architecture,

being less than 35°.

School of Planning and Architecture, New Delhi 110002, India.)

At this time the building opposite shades the northern facade even if the street is relatively wide.

Figure 15- Street elevation

33

Image source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India.

(a)

(b) Figure 16(a), (b) Streets of Jaisalmer

House The whole idea of a house is developed around the concept of â&#x20AC;&#x2DC;privacyâ&#x20AC;&#x2122; thereby generating very specific expressions and elements.

The ground floor has no openings on the street except the entrance door approached by some steps; the houses are on a plinth. These plinths became informal interactive spaces in front of those houses where people do not have a strong notion of privacy. The house starts opening up as one moves up from the street. The need for privacy from the house across the street is much less as compared to from the strangers passing through the street. 6

6

Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre,

Ahmedabad, India.

34

Figure 17- A façade of Jaisalmer

Depending upon the socio-economic status of the inhabitant, There are three types of houses in Jaisalmer: 1. Small Houses 

Undressed stone



Mud mortar finished with mud plaster.



Single storey house

Figure 18-House form- Small houses (Image source: Gupta, Vinod; Natural Cooling Systems of Jaisalmer

35

Assistant Professor of Architecture, School of Planning and Architecture, New Delhi 110002, India)

2. Middle Income People 

Two Storey



The front part of the first floor has a balcony projecting onto the street.

Figure 19-House form- Middle income people (Image source: Gupta, Vinod; Natural Cooling Systems of Jaisalmer Assistant Professor of Architecture, School of Planning and Architecture, New Delhi 110002, India)

3. Haveli 

3-5 Storey



Projecting balconies and carved

element

like

jharookhas on the upper floors

Figure 20-House form- Haveli (Image source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India.)

36

4.1.1.3 Response to climate 1. Town The town is protected by the dust storms entering from the southwest into the city. The major streets aligned at 90 degrees from the dust storms. The topography of the fort is at a higher level, protecting the city from major dust storms and heat.

Figure 21- Schematic sketch of orientation of streets and direction of wind storms (Image Source: Gupta, Vinod; Natural Cooling Systems of Jaisalmer Assistant Professor of Architecture, School of Planning and Architecture, New Delhi 110002, India)

37

The general street orientation is south-east to north-west axis. Most of the havelis buildings are oriented towards east and west axis longer walls are facing towards north and south direction and shorter walls

(a)

facing towards east and west direct to avoid the direct solar radiation.

(b) Figure 23-Street section of Jaisalmer; Figure 22 Streets of Jaisalmer

(a) Summer Solstice, (b) Winter Solstice

Figure 24- Town plan of Jaisalmer city (Image source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India ; https://architexturez.net/doc/az-cf-123687)

38

2. Clusters: The clusters are arranged in a compact manner. The width of the streets also being narrow and compacted so as to get mutual shading from the surrounding buildings.

3. Dwelling: With compact organization, the house and streets become very close to each other, so the most natural thing was to close the house to the exterior and open it to the interior, thus the courtyard became essential. This idea is reinforced by climatic needs. The courtyard acts as a heat sink in summer day time and is used for sleeping at night. (Courtyard effect)

4.2.1 Neighbourhood Level

The plan at neighbourhood level is predominant in the city.

Figure 25-Neighbourhood plan of Jaisalmer city (Image Source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India)

39



The streets are compact and radial in nature and the height of the buildings vary, which diverts the direction of wind.



The streets of Jaisalmer spends most of the day in shade because of tall buildings on either side, the air that passes through the facade from the street is much cooler than the air exposed to the sun. The cool air enters through the haveli's front facade, circulates through the rooms and then escapes through one of the courtyards taking out the hot air along with it.



With compact organization, the house and the streets become very close to each other, so the most natural thing was to close the house to the exterior and open it to the interior thus making the courtyard an extremely important feature of the house. This court the focus of haveli, is surrounded by interior rooms and passageways which lead via otla in front of each house to the neighbourhood street.



The idea of an inward looking house is also reinforced because of climatic reasons. Almost every house is built of yellow sand stone in dry masonry within an order that prevails over the entire settlement.

4.2.2 Clusters

The cluster plan of Jaisalmer is predominant in the city and shows the existing patterns of street and arrangement of the houses in the cluster.

40

Figure 26- West elevation of the street (Image Source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India)

Figure 27-Plan of a Jaisalmer cluster (Image Source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India)

ď&#x201A;ˇ

The streets are running north-south in figure 28. The width of the street is 12 meters in the north direction and tapers up to 4 meters in the south direction.

ď&#x201A;ˇ

The two long faces of building are joined by the neighbouring building i.e. the building are compactly placed, the long walls are shared walls so that there is less intake of heat inside the building.

41



Every house has a courtyard which is a major source of heat sink into buildings.



They will have better shading conditions in summer and better light conditions in winter.



The elevation shows the build structures are double and triple storeyed which will help in shading the street as well as otlas which is a becomes an interactive space for the neighbouring houses.



The neighbourhood buildings that are low heighted, are shaded by the double or triple storeyed houses.



Every house (as shown in the Figure 27) has balconies and jharookas which shade the lower floors and is also a source of light and ventilation.



The façades of the building are carved (textured) which helps in shading by texture.

The street section of the

cluster shows the shadow pattern of the of the buildings on the street on June 21 (summer solstice) and December 21 (winter solstice).

Figure 28-Schematic section of the street in the cluster (Section showing the altitude angle of sun at 12:00 P.M.)

42

Figure 29-Schematic section showing heat ingress inside a building

43

Figure 30- Shadow analysis of Jaisalmer cluster as on June 21 from 7:00 A.M. to 12:00 P.M.

44

Figure 31- Shadow analysis of Jaisalmer cluster as on June 21 from 1:00 P.M. to 06:00 P.M

Figure 32-Narrow compact streets, with fairly high buildings provide shade.

45

4.2 Jodhpur 4.2.1 City level

4.2.1.1 Historical Background

The second largest city in the Indian state of Rajasthan, this â&#x20AC;&#x153;Blue Cityâ&#x20AC;? is a mesmerizing collection of azure abodes that soothes and delights anyone that beholds it. Jodhpur is a prominent city of Rajasthan and is a reservoir of magnificent palaces and majestic forts. It is referred to as the Blue City due to the indigo tinge of the whitewashed houses around the Mehrangarh Fort. The old city of Jodhpur is surrounded by a stone wall and the new city is on the other side of the railway tracks, in the southeastern direction. Situated about 600 kms southwest of New Delhi, the origins of Jodhpur date back to 1459 when the foundations were laid by the famous Rao Jodha of the Rathore dynasty. It has since been the capital of Marwar and an oasis in that arid country.

The old city of Jodhpur was a fortified town ringed on all sides by massive sturdy walls and bastions with seven impressive gateways, each named after the other major towns in Marwar, they happen to face.

Rising in the middle, high above the city, is the daunting citadel of The built environment

Mehrangarh, an invincible fortress within

of the city is actually typical of

which are juxtaposed exquisitely carved

the traditional architecture of Rajasthan.

It

buildings

with

consists

of

exquisitely

carved stone facades, beautiful courtyards, zharookhas, narrow meandering streets perfectly negotiating the terrain,

46

stone palaces. Spread out between Mehrangarh and the city gates lies the historic city.

Figure 33- Schematic plan of Jodhpur

terrain compact bazaars, community spaces and religious buildings, all put together harmoniously. Yet the topography gives it a distinct built environment compared to other cities of Rajasthan. Taken together with the strong community structuring it has resulted in a very interesting organic character.

The topography and the climate needs of the arid zone made compact organization essential. This resulted in the development of a densely built city.

4.2.1.2 Architecture

The walled city of Jodhpur is sited on a natural sloping ground, where the undulating terrains end and the plains begin. The walled city is fenced by 10 km long wall with eight Gates leading out of it. The entire region on the north and north-west, due to the topography, is difficult for habitation. Responding to the topography and the climatic needs have resulted in a compact organization of spaces. However, the forces of nature have resulted in a development of dense built fabric with narrow meandering streets, going up and down in order to negotiate the topography, making space for socio-cultural and socio-religious activities in the form of open Chowks. Planning in such climatic region is typical, where the layout is very compact and the only open space seen in such areas are Chowks, varying in scale from the large one in the Mohallas to the one within the house.

47

The traditional Mohallas in Jodhpur have evolved over a period of 500 years, starting from the foothills; the Brahmpuri, Gundika Mohalla, and growing southwards, towards Bamba Mohalla. The Mohallas were caste or profession based, for E.g. Sonaronkighati, Bohronki pol, Muthonka

bas,

Joshiyon

ka

bas.

The

Mohalla

comprised

of

houses/Havelis, religious buildings, community spaces and circulation area. The bazaars, traditions, crafts and products, culture and value systems have also been reflected in the built form, existing in the walled city.

Most of the houses are planned in typical Rajasthani style with flat terraces and open

courtyard,

windows

and

with

decorated

doors,

balconies

having

elegant

balustrades or perforated screens. Main roads have double storied houses built of stone with shops at lower levels and residences above

Figure 34- Built Forms in

Jodhpur

The houses have high plinth with projects platform facing the street, which is used as interaction spaces. The houses had narrow openings in form of jharookhas, and a small gateway for entry.

Courtyard remained the central focus of the house in response to the climatic consideration. Away from the fort, on plain terrain, the streets are wider making vehicular movement possible. The stone paved streets run up and down, following the course of the natural water runoff. The variety and quality of the space-light relationships in these streets are almost ethereal. As in any traditional city of India the streets of Jodhpur are dynamic; interesting places for interaction and various

48

socio- economic, socio-cultural and socio- religious activities. They possess a very rich and intimate architectural vocabulary.

The residential areas have been expanded radially with the fort as their symbolic and physical centre. Housing grew, changed and improved until it reached a high level of sensitive design, both spatially and climatically. These areas present a very strong and closely- knit physical and social structure. The built structures are two and three storey houses with terraces, courtyards and ottas. They have raised platforms at the entrance of a house, immediately adjacent to the street. As one walks along the narrow streets, one feels the houses growing higher and higher. The built mass seems to rise towards the fort.

Figure 35-Fort overlooking the blue city of Jodhpur

The play of stone mass and terraces is strongly revealed by the sharp sunlight playing on the houses. The houses are painted blue or white, giving the city a unique character and identity. The residential clusters are formed on the basis of the residentsâ&#x20AC;&#x2122; profession. Therefore Brahimns live in Brahmapuri, goldsmiths in Sunaraon Ki Ghati, and moneylenders in Bohron Ki Pol. Each of these areas is entered through a gate which marks the beginning of its territory.

49

Once a year, all their houses are painted with a tint of blue. This colour, a strong reflector of sunlight, helps to keep the interiors cool by day and also lends a strong identity and character to the area.7

4.2.1.3 Response to climate

The city of Jodhpur has a traditional urban character that comes out as a response to the climate, the site conditions and the culture.

Buildings of blue colour, carved stone facades, jharookhas, meandering streets, courtyard houses, Bazaars, open Chowks, community spaces, temples and water structures make the blue fabric of the city. These

7

Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre,

Ahmedabad, India.

50

open spaces are quite significant in the social lifestyle of the people forming the meeting spaces and are centre of activities.

The water bodies helps in keeping the climate cool, and act as a node for the social and cultural activities. The topography and the climate made compact organization essential. This resulted in the development of a densely built city.

Figure 36- Town Plan of Jodhpur Image source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India; https://architexturez.net/doc/az-cf-123687

51

4.2.2 Cluster

Figure 37- Cluster1: Jodhpur (Image Source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India)



The street is oriented E-W. The west face of the street is blocked by the houses and a perpendicular street (orienting N-S) has some front faces of house.



Narrow and winding streets make airflow slow.



The streets would be shaded till 10:00 A.M. in the morning.



The orientation E-W is privileged because of its high potential of solar access indoors and outdoors needed in wind.



There is an easier seasonal solar control for the buildings walls oriented N-S (i.e. E-W streets) as the walls are protected in the summer and exposed in the winter.



For the pedestrian, the orientation hardly affects the irradiations.

For higher latitudes, the sun position is lower in the winter and creates strong obstacles. Thus, the irradiances reduce for high latitudes and this is especially obvious for the E-W orientation.

52

The irregular pattern of streets helps in diverting the wind pattern in the city. Here is an example of the cluster in which streets are cutting in irregular pattern. Almost every house has a courtyard which helps in cutting down the heat.

Figure 38- Cluster 2: Jodhpur

Below is the shadow analysis of the cluster showing the patterns on the streets as well as neighbouring buildings:

53

Figure 39-Shadow analysis of cluster of Jodhpur as on June 21 from morning 6:00 A.M. to 2:00 P.M.

Figure 40-Shadow analysis of cluster of Jodhpur as on June 21 from morning 3:00 P.M. to 6:00 P.M.

Figure 41-Street section â&#x20AC;&#x201C;Jodhpur

54

4.3 Nagaur 4.3.1 City level 4.3.1.1 Historical Background The ancient city of Nagaur in the Marwar region of central Rajasthan was one of the first strongholds of Muslim power (12th–16th century) in northern India. Located on a major caravan route, it was also an important centre of Sufism and, at its height, the presence of celebrated Sufi sheikhs made it a place of learning and pilgrimage, with its many fine mosques, tombs and other monuments associated with this period of Muslim rule. At its heart, Ahhichatragarh (translated as “cobra-hood fort”), the Fort of Nagaur, with its palaces and Mughal water gardens, once stood proud, where its walls rose high above the low-rise historic crossroads town in the centre of the region.

4.3.1.2 Architecture Built on a small hillock, the topography of the Fort’s plinth itself is generally flat. The rest of the city is

also

relatively

flat

and

unexceptional in terms of contours.

Figure 42-Schematic town plan of Nagaur

Nagaur is characterised by several features that are comparable to features in other towns of that region. In its overall organisation the street pattern conforms to an organically evolved layout where the geometric grid is located by the meandering structure of the streets. The oldest part of the town occupies the northern part of the hill and the fort thereby getting protection against the sandstorms. The large temple in

55

the south-west of the town also helps in cooling as the winds in the summer blow over the tank before passing over the town.

The arid hostile climate of Nagaur has brought about the development of a particular kind of building response in the region.

These buildings are introverted-turned towards internal controlled spaces and gardens. The gardens also contain water bodies which cool the environment. There is an extensive use of semi-open spaces either in front of a water body to catch the cooled breeze, or on the terraces.

Terraces serve as a good climatic element.8

4.3.1.3 Response to climate

The fort at Nagaur, called Ahichattragarh, is also set atop a hillock occupying the highest topographical location in the town. It provides protection against sandstorms and strong winds. This is a very significant aspect of the development of an urban settlement in the region.

8

https://archnet.org/system/publications/contents/8736/original/DTP101235.pdf?1391602913

56

Figure 43-Town plan of Nagaur Image Source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India; https://architexturez.net/doc/az-cf-123687

57

5. CAE STUDIES (DWELLINGS) CASE STUDY 1: HAVELI

Figure 44: Plan and section of Haveli of Jaisalmer (Section showing the altitude angle of sun is at 12:00 P.M.) (Image Source: https://architexturez.net/doc/az-cf-123687)



ORIENTATION: The longer axis of the ‘haveli’ is oriented in the eastwest direction giving less exposure to solar radiation.



BUILT FORM: The plan form of the ‘haveli’ is in the shape of trapezium, giving two long walls exposed.

58



ZONING: The entrance is through the east face through a semi covered space called ‘otla’. The ‘otla’ is covered by the projections of the first floor making it a comfortable space.



OPEN SPACES: There are two courtyards in the ‘haveli’ measuring 3.5 meters by 4.7 meters. One courtyard cuts through and through from the ground floor to the terrace. The other courtyard is on the second floor to the terrace. The width to height ratio is 1:3 approximately. The street is completely in shade because of the width (street) and height (haveli) ratio 1:3.5 approximately.



WALL: The west and south walls are blank walls blocking the heat into the ‘haveli’ by sun. Another build structure of two storey is attached to the west face of the ‘haveli’ which gets shaded in day time. The east façade is intricately carved with stone to shade the building façade through texture. The wall thickness is 600mm and is made of stone.



ROOF: The thickness of the roof is 300mm and is also made of stone.



SHADING

DEVICES:

The

projections

of

the

balcony

and

‘jharookhas’ are on the east and the north façade allowing natural light to enter through openings. Less number of openings open to external face of the wall. The altitude angle of the sun in summer solstice is 72 degrees and in winter is 39 degrees. The shadow forming through the shading devices is shown in the section above.

Percentage of openings to floor:

59

FLOORS

PERCENTAGE

OF

OPENINGS

ON FLOORS Ground Floor

7%

First Floor

20%

Second Floor

20%

Third Floor

10% Table 3: Percentage of openings to floor of Jaisalmer Haveli

Table 4-Mapping of climatic elements v/s design parameters of haveli 1 60

61

RURAL LEVEL CASE STUDY 2: THE ROOPSI HOUSE, JAISALMER Roopsi is a village of about 2000 people, located about 20 kilometres west of Jaisalmer town. Although in the desert region, its immediate surroundings have patches of cultivable land and rocky mounds, the climate is hot and dry with moderate to server sandstorms in the summer.

The winters are cold.

The central courtyard is the key element of the house. All the surrounding rooms open only into the court. 

It is a typical example of stone house which is mud plastered to get insulation from the heat.



The entrance is from the west and there is equal distribution of floor area on the x-axis and y-axis.



Squarish in shape it has rooms placed around an open court on side and on the other side a high compound wall.



Stone ‘chajjas’ on the periphery of the wall keeps the wall shaded from the sun. The ratio of built to open spaces is almost equal. This signifies the extensive use and importance of open spaces. These open spaces have mud plastered surfaces.



The rooms are spanned with stone slabs and there are stone columns in rooms having longer spans.



Room 1 has the longer axis towards the east-west façade, allowing the natural light to enter through the north. The orientation of room 1 helps in minimising the heat inside.



Room 2 has the longer axis towards the north-south façade. Wind enters through the entrance and west façade is heated up the most. There is a buffer space (open court) in front of the room 2.

62

Openings, which are very few in number are also very small in size



to keep the sun away.





The walls of the room are made of solid stone wall along with mud plastering, absorbing the maximum heat.

Use of shading devices to cover the openings from the sun. (walls and doors)

Figure 45-Plan and section of Roopsi house, Jaisalmer (Section showing the altitude angle of sun is at 12:00 P.M.) Image source: Jain, Kulbhushan and Minakshi; Typology and Mapping of Housing

Zones ,Western Arid Region,

School of Architecture, C.E.P.T., Navrangpura, Ahmedabad June 1988.

Table 5-Mapping of climatic elements v/s design parameters of Roopsi House, Jaisalmer 63

CASE STUDY 3: HAVELI 2

Thermal Comfort in the havelis of Jaisalmer, June, 2000, London, by Jane Matthews, School of Architecture, University of East London

(Section showing the altitude angle of sun is at 12:00 P.M.)

Figure 46- Plan and section of Haveli 2

64

65



ORIENTATION: The ‘haveli’ is oriented in north-west to south east direction.



BUILT FORM: The plan form of the ‘haveli’ is in the shape of rectangular, giving two long walls exposed.



ZONING: The entrance is through the east face through a semi covered space called ‘otla’. The ‘otla’ is covered by the projections of the first floor making it a comfortable space. The courtyard is placed in the centre, providing light and ventilation to the rooms placed around it.



OPEN SPACES: There is one courtyard measuring 5m x 3.5m. The height of the ‘haveli’ is 12 meters. The shading in the courtyard is shown in the section above. There is open space outside the winter room on the second floor.



WALL: The thickness of the wall is 400 mm built entirely of stone. On the ground floor, 3 wall faces are solid walls. There are openings on the NW and SE façade on the first and second floor. The walls are extensively carved which provides shading through the texture.

Use of parapet walls to create shade on the roof.



ROOF: The roof is also made of stone.

66



SHADING DEVICES: The projections of the ‘jharookhas’ are on the north-west and south-east façade. There are long projections above the openings for shading.

Percentage of openings to floor: FLOORS

PERCENTAGE OF OPENINGS ON FLOORS

Ground Floor

8%

First Floor

15%

Second Floor

12% Table 6- Percentage of openings to floor of Haveli 2



STREET: The street is completely in shade because of the width (street= 2 m) and height (haveli= 12 m) ratio 1:6.



The haveli also contains a basement room which remains cool than other rooms.



The second floor has a terrace space outside the room which can be used for sleeping in summer and for sitting under the sun in winters.

Table 7: Mapping of climatic elements v/s design parameters of Haveli 2, Jaisalmer 67

68

CASE STUDY 4: PATWA HAVELI

PLAN

SECTION SHOWING RADIATION CONTROL AND NIGHT VENTILATION

SECTION SHOWING WIND PAVILION AND SHAFT

Figure 47- Plan and section of Patwa Haveli (Image source- Rethinking tradition-Passive housing in the desert, Jaisalmer, Rajasthan, India by Kartikeya Rajput)

69

ORIENTATION: North-west to south east oriented building.

BUILT FORM: Rectangular form ZONING: The ‘haveli’ is a six floor building consisting of three main floors, two wind pavilions and a basement floor. The courtyard at ground is surrounded by ‘verandah’ on all sides with additional row of rooms in front and back of the ‘haveli’. The building projects out on every floor both towards the street and the courtyard. The two connecting staircases act as wind shafts.

WALL: Made of stone ROOF: Made of stone SHADING DEVICES: Projections like ‘jharookhas’, balconies and ‘chajjas’ shade the lower floors.

STREET: the entire street façade is covered with stone carved finned surface, balconies and sun shade.

WIND SHAFTS: Narrow vertical ducts and staircase shafts for deflecting wind into the built form

70

CASE STUDY 5: A HOUSE IN MATHURON KI POL, JODHPUR

Figure 48-Plan of a house in Mathuron ki Pol, Jodhpur (Section showing the altitude angle of sun is at 12:00 P.M.)

71

(Image source: Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi

centre, Ahmedabad, India)



ORIENTATION: The longer axis is towards east west orientation.



BUILT FORM: The built form is rectangular. The floor area decreases on the first floor giving a terraced court and also providing shade on the roof of the lower floor.



ZONING: The habitable spaces are placed on the east facade, passing through gradations of light and heat.



OPEN SPACES: The courtyard measures 3m x 2.5m. The height of the building is 8.2 m.



WALL: The walls are 300 mm and is made of stone. Walls on the west, east and south facades are blank walls.



ROOF: The thickness of the roof is 150 mm and is also made of stone.



OPENINGS: The rooms get ventilation through courtyard. There are less number of openings.

Table 8: Mapping of climatic elements v/s design parameters of a house in mathuron ki pol, Jodhpur

72

the Indian desert, January 2000, Aadi

centre, Ahmedabad, India)

(Image source: Jain, Kulbhushan and Minakshi; Architecture of

Figure 49- Plan and section of Jodhpur Haveli

73

CASE STUDY 6: A HAVELI OF JODHPUR

74



ORIENTATION: Both the axis shows equal distribution for all the faces.



BUILT FORM: The plan form is in a shape of square and the haveli has two floors with a terrace.



ZONING: The entrance is through the south face through a semi covered space called ‘otla’. The courtyard is surrounded by ‘osari’, a semi covered space on east and west side and rooms are placed after ‘osari’.



OPEN SPACES: There is one courtyard measuring 5 m x 5 m. The width to height ratio of the courtyard is 1:2.6 approximately. The shadow pattern in summer and winter solstice is shown in the figure.



WALL: The walls are 200 mm and is made of stone.



ROOF: The thickness of the roof is 150 mm and is also made of stone.



OPENINGS: The rooms get ventilation through courtyard. There are no opening in the rooms.

Table 9: Mapping of climatic elements v/s design parameters of a Haveli in Jodhpur 75

76

CASE STUDY 7: PALANA DISTRICT, BIKANER

Figure 50-Plan and section of a house in Palana district (Section showing the altitude angle of sun is at 12:00 P.M.)

77

(Image source: Jain, Kulbhushan and Minakshi; Typology and Mapping of Housing

Zones ,Western Arid Region, School of Architecture,

C.E.P.T., Navrangpura, Ahmedabad, June 1988)



ORIENTATION: Both the axis shows equal distribution for all the faces.



BUILT FORM: The six rooms are rectangular in shape placed on the north, south and east side. One of the room, circular in shape is placed on the west side which helps in blocking the wind to enter.



ZONING: The entrance is through the east face through a semi covered space called otla. The inhabitable room is placed on the west side so that habitable rooms get cooler. There is a court in between the rooms which is oriented in east west direction.



OPEN SPACES: There is one courtyard which is surrounded by the rooms. The width to height ratio of the courtyard is 7:3. The shadow pattern in summer and winter solstice is shown in the figure 51.



WALL: The walls are 400 mm and is made of mud. Mud has thermal properties which cools down the interior of the house.



ROOF: The thickness of the roof is 200 mm and is also made of stone in case of rectangular blocks and thatch roof is formed for circular room.



OPENINGS: The rooms get ventilation through courtyard. There is no opening in the rooms. Only the kitchen has one window opening and is well ventilated.

78

ď&#x201A;ˇ

The long and narrow semi-public front yard also provides access to the open side yard, which has a rectangular room on the west face and a backyard. The open space forms about 75% of the built area.

Table 10: Mapping of climatic elements v/s design parameters of Palana district, Bikaner

79

80

CASE STUDY 8: TEJIAVAS DISTRICT, BARMER

Figure 51- Plan and section of a house in Tejiavas, Barmer (Image source: Jain, Kulbhushan and Minakshi; Typology and Mapping of Housing Zones,Western Arid Region, School of Architecture, C.E.P.T., Navrangpura, Ahmedabad, June 1988)

81



ORIENTATION: The house is made up of circular rooms, clustered into an open yard. Every circular room is placed in an irregular pattern.



BUILT FORM: The cylindrical hut takes less heat inside the house and doesn’t allow the wind to enter inside.



OPEN SPACES: There is an open yard which occupies 70% of the built area.



WALL: The wall is 300mm thick and is made up of mud, and painted white in colour.



ROOF: The roofs are conical in shape and are made up of thatch.



OPENINGS: There are no window openings and the rooms get ventilation only from the door openings.

Table 11: Mapping of climatic elements v/s design parameters of Tejiavyas district, Barmer 82

83

TECHNIQUES USED IN THE CASE STUDIES 1. Courtyard

Courtyard is the very important technique in cutting down the heat inside the house. Courtyard behaves

differently

in

summer

(day and night) and winter (day Figure 52- Stack effect of courtyard in

and night).

daytime and night-time.

Figure 53- Gradations of light and heat in verandahs next to courtyard

2. Jharookha

Figure

54-

Showing

shading

by

jharookhas in the havelis Figure 55- Section of Jharookha

84

3. Shading by wall texture The

walls

of

Jaisalmer

(as

mentioned earlier) are intricately carved. The carving helps in shading the lower floors. The section shows the shading on street by neighboring building and carved facades of buildings.

Figure 56Section showing the street and carved faรงade of the building

Figure 57- Detail of a building faรงade

4. Walls The walls studied in the dwelling are stone wall and mud wall. The thickness varies in the havelis and houses of urban and rural level.

Figure 58-Stone Wall wall

Figure 59- Mud

Urban level

Rural level

Surface:

Surface:

Textured

Smooth

5. Shading devices The shading devices like chajjas, help in reducing the intake of solar radiation in the houses. The illustration

of

solar

radiation

entering into the building on summer

solstice

and

winter

solstice is shown in the section.

Figure 60-Section of a shading device above window

85

6. Jaali The jali helps

in

lowering

the

temperature by compressing the air through the holes.

Figure 61- Schematic section of Jaali

Table 12: Techniques used in the case studies

SUMMARIZATION OF CASE STUDIES: The settlements are built responding to climate of Rajasthan. The materials and techniques used at rural and urban level differs as the activity pattern of the people differs and space allotment at rural and urban level is different. The materials and techniques of every settlement discussed above is summarized below:

CASE STUDY

MATERIAL DETAIL

TECHNIQUES

(WALL, ROOF) RURAL LEVEL



Wall:

wall,



Open yard

Stone

wall



Circular forms and

plastered

with

mud

Mud

conical roofs 

Rectangular forms and stone roofs



Orientation

86



Roof:

Conical

thatch roof, Flat stone wall roof URBAN LEVEL 1. House

2. Haveli



Wall: Stone



Courtyard



Roof: Stone



Orientation



Wall: Stone



Courtyard



Roof: Stone



Jharookhas



Shading

by

wall

texture 

Wind shaft



Wind pavilion

Table 13-Summary showing the materials and techniques used in the case studies

6. INTRODUCTION TO BUILDING PROBLEMS IN HOT AND DRY CLIMATE

“The primary purpose of a building is to shelter the occupants from unfavourable outdoor conditions such as heat, cold, wind and rain. Thus, the building should be designed to provide a desirable indoor climate.”

By worldwide concern on sources of energy and environmental issues, many factors should be considered altered at the design stage of buildings. Through those issues to be considered at is the suitability of the

87

building design and materials in terms of climate properties. According to a large number of research works in order to indicate the climatic suitability of the building design and building materials, designers and/or architects have to be aware of the climatic characteristics of their working environment. Moreover, based on the related climatic elements, they will be able to categorize the building problems and apply or suggest their solutions to avoid them. This progress is defined as climatic design, having taken into consideration the climatic parameters of the area. In order to have successful climatic design in hot climates, which is the main focus in this study, first of all, the factors of the hot and dry climate.

Three factors have been commonly identified, on the basis of which the studied is continued.

These factors are: 1. High temperature 2. Wind 3. Glare

88

7. TECHNIQUES FOR CONTROLLING TEMPERATURE, WIND AND GLARE IN RAJASTHAN 7.1 Temperature control In hot and dry climates, the most important factor is to cut down the heat gain inside the building. The main concern is to reduce the day time high temperatures and to provide a comfortable indoor environment.

Figure 62- Solar radiation on sides of the building (Source: Watson D., Kenneth Labs, Climatic building design â&#x20AC;&#x201C; energy efficient building principles and practice, McGraw Hill, New York, USA, 1983)

The dwellings are exposed to the harsh solar radiation throughout the day. The walls and roof gets heated up for several hours, which in turn heats up the interiors of the house. To reduce the impact of such heat depositing inside, temperature control is a foremost step.

Temperature control can be done from the following techniques: 1. Orientation 2. Built form 3. Building envelope

4. Openings

and

shading

devices 5. Open spaces- Courtyards and Outdoor space

89

Following design approaches & strategies have been formulated & drawn for hot & dry climate of Rajasthan.

7.1.1 Orientation The building is placed on the x-axis and y-axis; where the building shorter face should be on y-axis, reducing the heat gain inside the building.

Figure 63- Building orientation

7.1.2 Built Form For building form, according to few studies, it is recommended that in hot climates those forms, which have ratio of width/height equal to 1:2, are the most successful forms by considering that mostly cores should be located in south side with proper shading elements, because of high sun depth in this location. It should be noted that building form should be extended along east-west axis In addition to length-width ratio, the illustration above shows surface to volume ratio as another factor in order to have proper building form. The difference in percentage indicates the difference in heat gains and loss due to surface. to minimize east and west exposure.

Figure 64-The surface area to volume ratio of various building layouts (Source: Stay cool a design guide for the built environment in hot climates, Holger Koch-Nielsen Cromwell Press, UK, 2002)

90

Below there are some of the illustrations of the different types of building forms:

1. URBAN LEVEL: Cluster forms The built forms at urban level are clustered together which forms common open spaces and gets mutually shaded by neighbouring buildings.

CUBE

Merits

Demerits

- Heat sink through - All surfaces exposed shading devices.

-

Mutual

shading major parameter)

through

cluster -

formation Figure 65- Cube

to sun (roof being the Roof

being

by surfaces,

neighboring

more

to

buildings.

radiation.

flat

exposed the

solar

-Variety of windows can

be

which

added, increases

ventilation,

without

destabilizing

the

structure.

CUBOID

Merits Heat

sink

Demerits through Two

shading devices.

Mutual through formation

long

surfaces

exposed to the solar

shading radiation. cluster Roof surface area is by flat

and

hence,

91

Figure 66- Cuboid

neighboring

exposed more to the

buildings.

solar radiation.

Table 14- Merits and demerits of forms: Urban level

2. RURAL LEVEL: Detached houses The built forms at rural level are usually detached from each other, allowing wind to pass through the built forms. The common spaces and yards are used for domestic purposes and is planned according to climate.

CYLINDER

Merits

Demerits

- Half surface of the -No common walls shape

is

always -Limitation of roofing

shaded.

system

-Maximum volume Figure 67-Cylinder

(dome,

available inclined) with

the -Problem

smallest

structure, division

using

minimum

the

of

space

number of materials which

reduces

amount

of

surface

exposed obstruction

the and

to

high

winds.

Table 15-Merits and demerits of forms: Rural level

92

7.1.3 Building Envelope 7.1.3.1 Roofs In hot and dry climate, the buildings receive solar radiations throughout the year and to achieve thermal comfort indoors mechanisms are needed for cutting down the heat gain by the surfaces of the building. Roofs are in maximum contact with sun, thus affect the ambient temperature to a great extent. The solar radiation heats the roof which in turn reradiates the heat onto the ceiling and finally on to the room occupants. About a third of the unwanted heat that builds up in your home comes in through the roof. The table below shows the techniques of roof:

CONE

Merits

Demerits

- Absorbs less heat - Cannot be added than flat roofs.

onto

without

- Less exposure to removing solar radiation.

Figure 68-Cone

structural

elements that would

Maximum destabilize

available

volume dwelling.

with

smallest -

the

It

is

the not

structure, using the subdivided minimum number of compartments. materials

which

easily into

93

reduces the amount of surface exposed and obstruction to high winds DOUBLE ROOF

Merits

Demerits

- Acts as a heat - Cost of construction insulation

for

the

build block.

- Can be used as a storage space with Figure 69-Double roof

ROOF PONDS

heat sinker.

Merits Acts

Demerits as

a

heat - Possibility of leakage

source and heat sink into the building. in both winters and -Loss summers (a)

of

water

as

evaporation.

(Summers- Day time- -It is a technically the

reflecting demanding insulation keeps the

and

expensive solution.

solar

heat

away

from

the

water,

which

keeps

receiving through (b) Figure 70-Section of roof ponds (a) Summer; (b) Winter

from below

heat the

the it

cooling it.

It also requires the daily attention of the users and is not

roof very

suitable

space hot-arid regions thereby

for

94

Night

time-

the

insulation is removed and water, despite cooling

the

living

space below, gets cooler on account of heat losses by evaporation, convection

and

radiation.)

A

water

body

covering the roof functions similarly to a soil cover: it minimizes

the

diurnal temperature range.

INCLINED ROOF

Merits

Demerits

- Less exposure to -Cost of construction solar radiation due - Additional building to its shape.

material.

Figure 71- Inclined roof

REFLECTIVE SURFACE

ROOF Merits

Demerits

95

-Heat sink through -Glare coming from the

reflective buildings.

surface

(example-

waste white broken Figure 72- Section showing reflective roof surface

ceramic tiles, lime finish,

surface

coatings- paints) INVERTED

EARTHEN Merits

Demerits

POTS -Increased RADIATION TO SKY PART

SHADE

area

for

emission,

surface -Possibility of leakage radiative into and

the

an through the pots

insulating cover over the

roof

which

impedes the heat Figure 73- Section showing inverted earthen pots

flow into the building while still permitting upward heat flow at night.

DOMICAL ROOF

Merits

building

Demerits

96

-Curved roof has a -Further expansion for larger

convection upper floors in future is

heat transfer area not possible. and transfers heat more efficiently than Figure 74- Domical roof

a flat roof therefore, a

curved

roof

is

more easily cooled.

-During

the

day,

always some area of the

dome

shadow

is

in

while

at

night full hemisphere sees the night sky.

PLANT

COVER

ON Merits

Demerits

ROOF

-A

cover

deciduous

of -Initial cost of installing plants -Maintenance cost

and creepers is a -Place better alternative.

-Evaporation the brings

leaf

demands

higher on

the

from waterproofing system

surfaces of the structure.

down

the -May include insects

temperature of the

97

roof to a level than that of the daytime air temperature.

-At night, it is even lower than the sky Figure 75- Section showing plant cover on roof

temperature

Table 16: Techniques for lowering down the temperature through roof 7.1.3.2 Walls Walls are a major part of the building. Envelope receives large amounts of solar radiation. The heat storage capacity and heat conduction property of walls are key to meeting desired thermal comfort conditions.

The wall thickness, materials and finishes can be chosen based on the heating and cooling needs of the building. Appropriate thermal insulation and air cavities in walls reduce heat transmission into building which is the primary aim in a hot region.

SOLID WALLS

Merits

Demerits

-Solid walls with high - Solid stone wall thermal

capacities occupies

are common in hot space

than

arid climates, as they brick wall. transfer the absorbed heat to the interior Figure 76-Solid Wall : Brick

with a time lag, thus restraining the heat

more solid

98

when

external

temperatures

are

high, and releasing it when

temperatures

are low.

-Typical solid walls are made of stone, earth, Figure 77-Solid Wall : Stone

burnt clay bricks and concrete.

-Insulation

on

the

outside of a solid wall gives

a

four

times

greater time lag than if it were placed on the inside, but it also hinders

heat

dissipation during the night.

CAVITY WALLS

Merits -Cavity better

Demerits walls

give -A disadvantage of

thermal cavity walls is that

insulation than solid insects and vermin walls. It is because of may nest in them. the space provided between two leaves of cavity walls is full of air and reduces heat

99

Figure 78- Section

transmission into the

showing cavity wall

building from outside.

MUD WALL

Merits

Demerits

-Effective in cooling -Maintenance of the interiors

of

the wall

building.

-Termites

can

be

-High thermal mass is seen. very energy-efficient -Cannot take much in both summer and of the load, hence winter, and ideal for structure

height

is

passive solar heating limited. and cooling. Indoor -Roof construction is Figure 79- Section

temperatures

showing mud wall

only about 5 degrees wall between and

vary light in weight as the summer much load.

winter

(17-22

degrees), making it naturally

cannot

cool

in

take

100

summer and warm in winter.

LIME PLASTERED BRICK Merits

Demerits

WALL -It

reflects

solar - Techniques for lime

radiation hence less plaster brings trouble heat is absorbed by to labours. the wall.

Figure 80- Section showing lime plastered brick wall

Table 17: Merits and demerits of techniques for walls

7.1.4 Shading Devices

7.1.4.1 Shading through texture on walls The performance of solar passive cooling techniques such as solar shading, insulation of building components and air exchange rate was evaluated. A decrease in the indoor temperature by about 2.5째C to 4.5째C is noticed for solar shading. Results modified with insulation and controlled air exchange rate showed a further decrease of 4.4째C to 6.8째C in room temperature.

101

Although shading of the whole building is beneficial, shading of the window is crucial. The total solar load consists of three components; direct, diffuse and reflected radiation. To prevent passive solar heating, when it is not wanted, a window must always be shaded from the direct solar component and often so from the diffuse and reflected components. Decisions on where and when to include shading can greatly affect the comfort level inside a closed space.

TEXTURE ON WALLS

Merits Highly textured walls have a portion of their surface in shade The increased surface area of such a wall results in an increased outer surface coefficient, which permits the sunlit surface to stay cooler as well as to

Figure 81-Shading by texture on

cool down faster at night

walls

Table 18- Merits and of shading on walls through texture

7.1.4.2 Shading devices

HORIZONTAL DEVICES

Merits

102

-To shade a window during hot summer months -Allow sunlight to shine through window in winter, to help warm a building.

Figure 82- Horizontal Shading Device

VERTICAL DEVICES

Figure 83Device

Vertical

Merits -Vertical devices helps in shading east and west faรงade in afternoon sun.

Shading

EGG-CRATE DEVICES

Merits -High shading efficiencies -The horizontal elements control ground glare from reflected solar rays.

Figure 84- Egg-crate shading device Table 19- Merits and demerits of shading devices

103

7.1.5 Open Spaces 7.1.5.1 Courtyards COURTYARDS

Merits Acts

Demerits as

regulator

a

heat -Glare

as

will

be

hot present at the time

rises up and cool air of summer. enters the room.

Figure 85-Courtyard effect Table 20- Merits and demerits of courtyard

7.1.6.2 Outdoors CLUSTERS: OUTDOORS STREETS

Merits

Demerits

By orienting the Straight grid

pattern parallel

and streets

diagonally to the open the city to east-west Figure 86- Street: Grid diagonal to east-west axis.

axis, wind ventilation.

the sun exposure The grid pattern and

shade

is maximizes

better distributed radiation on

the

streets; throughout

such a grid still straight streets. supports

the

dynamic movement of air.

Figure

87-Section

shading on the street

showing

More important,

its

104

however, is the form of alleys and buildings.

Winding

or

zigzagging narrow

alleys

receive minimum radiation, reduce Figure 88- Zigzagging alleys

the

effect

stormy

of

winds,

establish shaded spaces throughout day

the which

provide a cool and comfortable microclimate Figure 89-Blocked streets

and

also

relatively

stay warm

during cold nights and in winter.

Storm effects can be reduced by blocking

streets.

105

Two-story buildings

with

closed

patios

open to the sky will

maximize

shade,

minimize

radiation, yet still retain ventilation and reduce the effects of stormy winds.

Buildings

should

be

attached (cluster)

to

reduce exposed surfaces.

Table 21- Merits and demerits of street layouts

7.2 Wind control (outdoors) 7.2.1 Plan form PLANFORMS

Merits

Demerits

Usually seen in rural Difficulty in forming areas

with clusters

detached

form level.

shapes,

forming

open spaces which allows wind to pass

at

urban

106

through the surface.

Due to the shape of the plan, the wind does not enter into the building.

Figure 90- Circular Planform

The

surface

is The surface is more

exposed to wind as it exposed

to

harsh

is flat and welcomes winds. wind

inside

the

building. a.

b.

Figure

91-Square

planform

In

(b),

the

orientation is tilted to 45 degrees which helps in reducing the effect.

Table 22-Merits and demerits of plan form

7.2.2 Surrounding Landscapes 7.2.2.1 Landform LANDFORM

Merits - In hot climates, a north slope would be preferable as it would receive the least direct radiation.

The building should be placed so

Figure 92- Planning on leeward side

as to maximize airflow.

helps in cutting the wind inside buildings Table 23- Merits of landform

107

7.2.2.2 Vegetation VEGETATION

Merits -Different

order

vegetation protect

used

building

of to from

undesirable breezes and solar radiation.

Figure 93- Vegetation helping in lowering down the temperature

Table 24- Merits and demerits of vegetation in controlling wind

7.2.3 Wind Catcher WIND CATCHER

Merits

Demerits

-The air taken from -Leakage of water elevated

tower

cooled

is and

down place

insects in

take such

through evaporative processes. cooling

and

is

allowed to enter in the Figure 94- Working of wind tower

house.

The

cooler air enters from a height and lowers the temperature.

Table 25- Merits and demerits of wind catcher

7.2.4 Openings JAALI

Merits

108

-The

wind entering into the building is controlled by the openings like â&#x20AC;&#x2DC;jaaliâ&#x20AC;&#x2122; which is perforated.

Figure 95- Section showing jaali Table 26-Merits of openings

7.3 Glare 7.3.1 Albedo Typical approximate values of various surfaces are as under: CATEGORY

PERCENTAGE

1. Dark surfaces

10%-30%

2. White colored surfaces

70%-80%

3. High reflective paints

80%

4. White ceramic tiles

70%

5. Heat resistance terrace 70% tiles

Table 27- Albedo values of certain materials

109

8. SUMMARY The present study explores the city level (town), neighbourhood level, cluster arrangements and settlements of Rajasthan at rural and urban level in terms of climatic design. The need of climatic design in Rajasthan is important as the temperature rises up to 45° C in summer daytime and drops down to 5°C in winter daytime. Hence, there is a need of climate responsive buildings to keep comfortable conditions.

Understanding the climate and their geographical associations are important for understanding the architecture of Rajasthan. The cluster based planning of the building blocks resulting in more compact utilities of network and provides shading on the street and neighbouring buildings.

The settlement study included materials, techniques

and

proportions of areas with volume which help in controlling heat entering inside the building. The settlements of the town are protected from the wind storms by the fort. The major streets of Jaisalmer are oriented towards east-west direction and the minor streets are oriented towards north-south direction. The streets of Jodhpur and Nagaur are organic in character.

The points discussed below are summarize the whole study of the settlements of various parts of Rajasthan. 

The

architecture

of

Rajasthan

is

having

some

special

characteristics like having a central courtyard which acts as the main source of ventilation and most of the activities are also performed here. 

The heat inside of the building is controlled by the use of textures in Jaisalmer. The front part of the facade which remains exposed

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are controlled by creating deeply carved patterns. This minimizes the heat gain by providing shading due to texture. In summer in day time when the major heat source is sun the exposed textured surfaces will be cooler than plain surfaces. In evening when ambient conditions are cool the increase surface area helps in cooling it faster. However, an extended surface will warm up faster than a plain surface under winter conditions due to low solar altitude, therefore the location in context of these surfaces is very important. 

The walls are made of stone in urban areas and of mud in rural areas. Both stone and mud have thermal properties which cuts the heat down.



Rectangular plan forms were seen at urban level while circular plans were clustered at rural level.



Projecting elements like chajjas, jharookhas, balconies are shading devices for the fenestration and walls.



There are less number of openings on the exterior face of the build block. Most of the openings open into the courtyard.

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9. CONCLUSION

This study included settlement of different regions across Rajasthan like Jaisalmer, Jodhpur, Nagaur, Barmer, Bikaner. It was found at macro level that the settlements of the town are protected from the wind storms by the fort and at micro level responding to climate at both urban and rural level.

Settlement patterns at urban level presented more of circular forms and were different in materials (mud walls, thatch roofs) and techniques, while those in urban areas exhibited rectangular forms clustered closely built with stone. Moreover, urban settlement included some elements for shading of walls and windows (like ‘jharookhas’, ‘chajjas’, balconies). The settlement at rural level were usually single storeyed structures, while at urban level double storeyed or even 5 storeyed (‘haveli’) were observed.

To provide shelter with comfortable living conditions indoor for its occupants, designing a climate responsive settlement is essential. The main goal of climatic design, on a macro (settlement) and micro (building) level, is hence to reduce uncomfortable conditions created

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by extremes of heat and dryness. Buildings must be adapted to extreme summer / winter and day / night conditions to achieve a well-balanced indoor climate. To design a climate responsive building, the role of an architect not only related to planning but to maintain the proportion among the all the parameters (techniques and materials) for minimising the heat gain inside the building.

Mentioned below are certain building parameters on which an architect should work. The importance of each parameter in designing is concluded below:

Table 28- Role of an Architect in providing comfortable indoor environment 113

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COMFORT REQUIREMENTS AND PHYSICAL MANIFESTATION The table below shows the objectives and their physical manifestations on which an architect works for the comfortable indoor environment: OBJECTIVES

PHYSICAL MANIFESTATION

1)Resist heat gain • Decrease exposed surface Orientation and shape of building area • Increase thermal resistance

Insulation of building envelope

• Increase thermal capacity Massive structure (Time lag) • Increase buffer spaces

Air

locks/

lobbies/balconies/verandahs • Decrease air exchange rate Weather stripping and scheduling air (ventilation during day-time)

changes

• Increase shading

External

surfaces

protected

by

overhangs, fins and trees • Increase surface reflectivity

Pale color, glazed china mosaic tiles etc.

2)Promote heat loss • Increase air exchange rate Courtyards/

wind

(Ventilation during night-time)

arrangement of openings

• Increase humidity levels

Trees,

water

ponds,

towers/

evaporative

cooling

Table number 29-Comfort requirements and physical manifestation

The ideal situations for settlements in hot and dry climate like Rajasthan:

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1. Orientation: The best orientation is along the east-west axis.

Orienting along this direction minimises overheating.

2. Forms: Rectangular or circular buildings are preferred over irregular forms with greater wind exposure.

3. Walls: Solid walls, cavity walls can be used. The materials that can be used are: Mud, Stone, Brick, Burnt clay bricks, Unburnt clay bricks, Solid concrete blocks, Hollow concrete blocks, Timber.

Surfaces can be white washed and insulation sheets can be coated.

4. Roofs: Hip roofs reduces heat load. o A double roof reduces re-radiation to the interior.

5. Shading: Locating the deciduous trees outside the windows for summer shade and winter sun. o Minimising the percentage of openings on the exterior faรงade and planning it along the courtyard. o Use of Jaalis and Jharookhas on the upper floors also help in minimising heat gain. o In hot arid climates, shading can also be provided by placing buildings closely together. o Fenestrations having 15-20% of floor area should be used.

6. Courtyard: The width of the courtyard should be less than the height of the building for maximum shade in the courtyards. In a hot and dry climate like Rajasthan, the internal organisation of structure should allow free cross ventilation and stack effect.

7. Street: The width should be such that the buildings on both the sides should shade the street in the afternoon hours.

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10. BIBLIOGRAPHY 1. Jain, Kulbhushan and Minakshi; Architecture of the Indian desert, January 2000, Aadi centre, Ahmedabad, India.

2. Jain, Kulbhushan and Minakshi; Typology and Mapping of Housing ,Western

Arid

Region,

School

of

Architecture,

C.E.P.T.,

Zones

Navrangpura,

Ahmedabad, June 1988.

3. Sharma, Rajesh; Int. Journal of Engineering Research and Applications; Sustainable buildings in hot and dry climate of India ISSN: 2248-9622, Vol. 6, Issue 1, (Part - 4) January 2016, pp.134-144.

4. Krishnan, Arvind; Climate Responsive Architecture: A design handbook for energy efficient, 2001.

5. Gupta, Vinod; Natural Cooling Systems of Jaisalmer Assistant Professor of Architecture, School of Planning and Architecture, New Delhi 110002, India.

6. Rethinking tradition-Passive housing in the desert, Jaisalmer, Rajasthan, India by Kartikeya Rajput.

7. Nayak, J.K., Hazra R., Prajapati, J.; Manual on solar passive architecture, December 1999.

8. Subramanian, C. V. 1, Divya M. 2; International Research Journal of Engineering and Technology (IRJET); Solar Passive Architecture Cooling Techniques; e-ISSN: 2395 -0056 Volume: 03 Issue: 12 | Dec -2016 9. Thermal Comfort in the havelis of Jaisalmer, June, 2000, London, by Jane Matthews, School of Architecture, University of East London 10. Baruch, Givoni; Climate considerations in building and urban design, 1998

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11. WEBLIOGRAPHY 1. https://architexturez.net/doc/az-cf-123687 2. https://www.sunearthtools.com/dp/tools/pos_sun.php#top 3. http://www.discoveredindia.com/rajasthan/culture-inrajasthan/architecture-in-rajasthan.htm 4. http://www.webpages.uidaho.edu/arch499/Jaisalmer/jaisalmermain.htm 5. http://collections.infocollections.org/ukedu/en/d/Jsk01ae/4.3.html 6. http://shodhganga.inflibnet.ac.in/bitstream/10603/63640/8/08_chapter%201. pdf 7. http://www.nzdl.org/gsdlmod?e=d-00000-00---off-0envl--00-0----0-10-0---0--0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0--4----0-0-11-10-0utfZz8-00&a=d&cl=CL1.1&d=HASH7fb3fd71d302d3efdfe64e.4.4 8. https://archnet.org/system/publications/contents/8736/original/DTP101235.p df?1391602913

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12. GLOSSARY

1. Albedo: Albedo is the ratio of the amount of radiation reflected to the amount received on a surface. High-albedo materials can save cooling energy use by directly reducing the heat gain through a building's envelope (direct effect) and also by lowering the urban air temperature in the neighbourhood of the building (indirect effect).

2. Chajjas: A ‘chhajja’ is the projecting or overhanging eaves or cover of a roof, usually supported on large carved brackets.

3. Chowk: Open-to-sky space like a city square or cluster space; also referred to courtyard in a house.

4. Comfort Zone: On the bioclimatic chart, the area of combined temperatures and humidities that 80% of the people find comfortable.

5. Diurnal Range: It is the variation between a high temperature and a low temperature.

6. Haveli: Large houses in the city.

7. Horizontal shadow angle: The horizontal shadow angle (HSA) is relevant for vertical shading devices such as fins. It is easy to determine: It's the angle between the normal of the window pane and the azimuth of the sun. (HSA = azimuth – orientation) 8. Jharookha: A small projecting space in a house like a balcony or a bay-window.

9. Otla: Raised Platform 10. Solar Radiation: Radiation emitted by the sun, including infrared radiation, ultraviolet radiation, and visible light.

11. Solstice: The dates of the shortest and longest days of the year.

Winter solstice is on December 21; Summer solstice is on June 21.

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Sun altitude is lowest at winter solstice and higher at summer solstice.

12.

Stack effect: The movement of air into and out of buildings,

resulting from air buoyancy. Buoyancy occurs due to a difference in indoor-to-outdoor air density resulting from temperature and moisture differences.

13. Sun path diagram: A latitude specific chart mapping the apparent movement of the sun and used to determine solar altitude and azimuth angles for a given time and date.

14. Time lag: The period of time between the absorption of solar radiation by a material and its release into a space. Time lag is an important consideration in sizing a thermal storage wall.

15. U-value: The number of watts that flow through one square meter of building component (e.g. roof, wall, floor, glass), in one second, when there is a 1 degree C difference in temperature between inside and outside air, under steady state conditions.

16. Vertical shadow angle: The vertical shadow angle (VSA) is a little

bit more difficult. If we imagine a virtual plane between the bottom left-hand and right-hand corners of the window and the sun, then the VSA is the angle this plane forms with the ground plane. The VSA is required when designing horizontal shading devices such as overhangs.

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13. APPENDICES 1. Sun path of Jaisalmer

Image source: https://www.sunearthtools.com/dp/tools/pos_sun.php#top

2. Sun path diagram of Jodhpur

Image source: https://www.sunearthtools.com/dp/tools/pos_sun.php#top

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List of major plant species found in Rajasthan Trees 1. Acacia Nilotica 2. Azadirachta Indica 3. Albizia Lebbeck 4. Bauhinia Variegata 5. Butea Monosperma 6. Cassia Fistula 7. Delonix Regia 8. Erythrina Indica 9. Pongamia Glabara 10. Tamarindus Indica 11. Zizyphus Jujuba

Climber 1. Bugainvillea species

Shrubs 1. Nerium Oleander 2. Tecomaria Capensis