It is a literature case study, which consist of two parts. 1st half covers the introduction of hot and dry climate and design factors that we consider while designing in hot and dry areas. And 2nd part consist of litrature case study of building "SANGATH - An Architect’s Studio, Ahmedabad By B.V. Doshi".

1. LITRATURE CASE STUDY

2. SUBMITTED BY:
CHETANA BHANWAL
1532781029
ARCHITECTURE DESIGN - IV

3. General remarks
Hot-arid zones or desert regions with scarce
vegetation and saline soils are distributed
throughout the world.
15% percent of the world’s population lives in
arid zones.
1/3 of the world’s land mass and 22% of all
potential arable land lies in the arid zone.
Most of the world’s energy reserves (oil) are
within or adjacent to these zones.
INTRODUCTION

4. Deserts with hot and dry climates are
warm all year round, and are extremely
hot in the summer. Usually, they have very
little rainfall, making the climate extremely
dry, and hard for plants and animals to
survive.
Animals in the hot and dry desert also
have special adaptations that allow
them to survive.
There are very few plants in hot and dry
deserts. Often, the only things that can
survive are short shrubs and trees. Plants
that live in the desert have special abilities
that allow them to live in such a hot and
dry place.
For ex : animals, like the camel, store fat in
one particular area (such as their hump),
providing surface area to dissipate heat.
Many animals are also light in color.

5. LOCATION

6. HOT AND DRY REGION IN INDIA
HOT AND DRY
REGION
•The hot and dry climate
in India prevails in north-
western region of the
country mainly from April
to June and in the rest of
the country from March to
May .
• Jaisalmer, Jodhpur
,Ahmedabad and Sholapur
are some of the city that
experience this type of
climate.
Ahmedabad
Jodhpur
Jaisalmer
Sholapur

7. HOT AND DRY REGION IN THE WORLD
Hot & Dry regions: Kutch, Algeria ,Peru ,Egypt ,Libya, Coober
Pedy SA, Ahmedabad, Rajasthan, North Africa, Pakistan etc.
kutch
Egypt
Libya
Peru
Coober pedy

8. Characteristics

9. • A typical hot and dry region is usually
flat with sandy or rocky ground
conditions, and sparse vegetation
comprising cacti, thorny trees and
bushes.
• The mean monthly temperature
remains 30 degree .
• Due to intense solar radiation (values
as high as 800-950 W/m2), the ground
and the surroundings of this region are
heated up very quickly during day
time.
i. In summer, the maximum ambient
temperatures are as high as 40-45 C
during the day and 20-30 C at night.
ii. In winter, the values are between 5 and
25 C during the day and 0 to 10 C at
night.
iii. It may be noted that the diurnal
variation in temperature is quite high,
that is, more than 10 C.

10. •The climate is described as dry because the
relative humidity is generally very low,
ranging from 25 to 40 %,
• The hot and dry regions receive less
rainfall – the annual precipitation being less
than 500 mm.
•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.
• 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.

11. DESIGN GUIDELINES

12. Objective
Resist
Heat
Gain
Promote
Heat
Loss
1. Decrease exposed
surface area.
2. Increase thermal
resistance.
3. Increase thermal capacity.
4. Increase buffer space.
5. Decrease air exchange
rate.
6. Increase shading.
7. Increase surface
reflectivity
1. Ventilation of
appliances.
2. Increase air
exchange rate.
3. Increase humidity
level.

13. PHYSICAL MANIFESTATION
Various Methods to reduce heat gain
in a building
• Building orientation
• Shading by neighboring buildings
• Shading by vegetation
• Roof ponds and garden
•Solar chimney
• Courtyard effect
• Air vent and wind tower
• Sensible and evaporative cooling
•Shading by overhangs, louvers and
awnings etc.
• Air cooling by tunnels
•Earth berming
•Thermal storage
•Opening and windows
•Orientation of opening
•Walls
•Roofs
•Shading of roof

14. •Building orientation
Maximum solar radiation is interrupted by the roof
(horizontal surface) followed by the east and west
walls and then the north wall during the summer
period, when the south oriented wall receives
minimum radiation. It is therefore desirable that the
building is oriented with the longest walls facing
north and south, so that only short walls face east and
west. Thus only the smallest wall areas are exposed
to intense morning and evening sun.
•Shading by Neighboring
Buildings
The buildings in a cluster can be spaced such that
they shade each other mutually. The amount and
effectiveness of the shading, however, depends on
the type of building clusters.

15. • Shading by Vegetation
•Shading by trees and vegetation is a very effective method of
cooling the ambient hot air and protecting
the building from solar radiation.
• The solar radiation absorbed by the leaves is mainly utilized for
photosynthesis and evaporative heat losses. A part of the solar
radiation is stored as heat by the fluids in the plants or trees.
• The best place to plant shady trees is to be decided by observing
which windows admit the most sunshine during peak hours in a
single day in the hottest months.
• Usually east and west oriented windows and walls receive about
50% more Sunshine than the north and south oriented
windows/walls
• Reflecting Surfaces
If the external surfaces of the building are painted
with such colors that reflect solar radiation (in order
to have minimum absorption), but the emission in
the long wave region is high, then the heat flux
transmitted into the building is reduced
considerably.

16. This solar chimney draws air
through a geometrical heat
exchange to provide passive
home cooling.
•Solar Chimney
•A solar chimney utilizes the stack effect, but here the
air is deliberately heated by solar radiation in order to
create an exhaust effect.
•One should distinguish between the stack effect
ventilation due to the building itself, and that due to a
solar chimney.
• In the former case, one tries to keep the increment in
the building temperature as small as possible and
hence the stack effect is weak.
• In the case of a solar chimney, there is no limit to the
temperature increment within the chimney,since it is
isolated from the used spaces. The chimney can
therefore be designed to maximize solar gains and the
ventilation effects.
•Courtyard Effect
•Due to the incident solar radiation in the courtyard, the
air in the courtyard becomes warmer and rises up. To
replace it, cool air from the ground level flows through
the louvered openings of the room, thus producing the
air flow.

17. •Sensible and Evaporative Cooling
•The heat loss from air results in a decreased air temperature,
but no change in the water vapor content of the air. Air in the
upper part of a wind tower is sensibly cooled.
•When water is introduced into a system, evaporative
cooling occurs. Such cooling involves a change in
both the water-vapor content and the temperature of
the air. When unsaturated air comes in contact with
water, some water is evaporated, thus lowering the
temperature of the air and increasing its water-vapor
content.
Fountain
Air Vent or wind tower
•A typical vent is a hole cut in the apex of a domed or cylindrical
roof. Openings in the protective cap over the vent direct wind across
it. When air flows over a curved surface, its velocity increases
resulting in lowering of the pressure at the apex of the curved roof,
thereby, inducing the hot air under the roof to flow out through the
vent. In this way, air is kept circulating through the room under the
roof. Air vents are usually placed over living rooms, often with a
pool of water directly under the vent to cool the air, which is moving
up to the vent, by evaporation.

18. •Shading by overhangs, louvers and awnings
Well-designed sun control and shading devices, either as parts of a building or
separately placed from a building facade, can dramatically reduce building peak
heat gain and cooling requirements and improve the natural lighting quality of
building interiors. The design of effective shading devices will depend on the solar
orientation of a particular building facade. For example, simple fixed overhangs are
very effective at shading south-facing windows in the summer when sun angles are
high.
Different types of shading devices.

19. • Air Cooling by Tunnels
The use of earth as a heat sink or a source for cooling/heating air in buried pipes
or underground tunnels has been a testimony to Islamic and Persian
architecture. The air passing through a tunnel or a buried pipe at a depth of few
meters gets cooled in summers and heated in winters (Fig. 10). Parameters like
surface area of pipe, length and depth of the tunnel below ground, dampness of
the earth, humidity of inlet air velocity, affect the exchange of heat between air
and the surrounding soil.
Working principle of earth air tunnel.

20. •Earth berming
In an earth sheltered building or earth beamed structure the
reduced infiltration of outside air and the additional thermal
resistance of the surrounding earth considerably reduces the
average thermal load. Further the addition of earth mass of the
building acts like a large thermal mass and reduces the
fluctuations in the thermal load. Besides reducing solar and
convective heat gains, such buildings can also utilize the
cooler sub-surface ground as a heat sink. Hence with reference
to thermal comfort, an earth sheltered building presents a
significant passive approach.
Working principle of earth berming during summer and winter
conditions.

21. •Thermal Storage
Thermal capacity effects in the materials result
in time delay as well as damping of the
parameters in the environment. As a result
temperature differences exist between the
materials and the environment around them
and this effect can be utilized for space cooling.
•Walls
•Good materials in hot-arid zones, combined with few openings and
light colored outer surface. Takes best advantages of time lag,
with heat emission at night.
In regions with large diurnal temperature ranges and nigh
especially in the absence of a ceiling - roofs should possess a large
thermal capacity with an appropriate time lag to balance
temperature variations. To achieve this they must be constructed
of heavy materials. The use of exterior or interior insulation has to
be considered carefully and its suitability depends on the
particular requirements and technical possibilities
•CAVITY WALLS
Has many advantages, especially in hot-arid zones. Reflective
surface in the cavity reduces radiant heat transfer. Ventilation
of the cavity takes the heat away and reduces conductive heat
transmission to the interior.

22. •Openings and windows are necessary for natural lighting and
ventilation, but heat gain in summer should be minimal.
During the daytime, the absence of openings would be
desirable, especially on the west side; or the openings should be
as small as possible and be shielded from direct radiation and
located high on the walls to protect from ground radiation . At
night, the openings should be large enough to provide
adequate ventilation for the dissipation of heat emitted by the
walls and the roof. Hence larger openings should be closed
during the day with insulated shutters and opened at night.
Such systems are not always reliable because they require the
attendance and readiness of the inhabitants. Other
considerations such as desired privacy and safety may prevent
the correct use of a system with shutters.
•Openings and windows
•Orientation and size of openings
•Main openings should face north and south, but the latter should be shaded either by
shading devices, roof overhangs or by deciduous trees. The size of the windows on the
west and east sides should be minimized in order to reduce heat gains into the house in
the early morning and late afternoon, or also be protected by particular shading devices.
A moderate, south-facing glass area catches the solar radiation during the cold season,
but should not be affected by direct radiation during the summer.

23. •Roofs
•In hot-arid regions the vault, the dome and the flat roof are the traditional
•The rounded form of a hemispherical vault (dome) has a larger surface area
than its base. Solar radiation is thus diluted and re-radiation during the
evenings is also greatly facilitated.
Example of dome and vault structure
•The flat roof is practical in areas where it seldom rains. It is also a good
reflector and re-radiates heat efficiently, especially if it consists of a solid, white
painted material. High solid parapet walls along the edge of the roof can on the
one hand provide daytime shade and privacy, but can have the disadvantage of
creating an undesired stagnant pool of hot air. The construction and exact
placement of parapet walls should therefore be carefully examined.
Example of flat roof

24. •Shading of roof
•Shading the roof is a very important method of reducing heat gain. Roofs can be shaded by
providing roof cover of concrete or plants or canvas or earthen pots etc.
•Shading provided by external means should not interfere with night-time cooling. A cover
over the roof, made of concrete or galvanized iron sheets, provides protection from direct
radiation. Disadvantage of this system is that it does not permit escaping of heat to the sky at
night-time .
•A cover of deciduous plants and creepers is a better
alternative. Evaporation from the leaf surfaces brings down
the temperature of the roof to a level than that of the daytime
air temperature. At night, it is even lower than the sky
temperature.
•Another inexpensive and effective device is a removable
canvas cover mounted close to the roof. During daytime it
prevents entry of heat and its removal at night, radiative
cooling. Fig. 5 shows the working principle of removable roof
shades. Painting of the canvas white minimizes the radiative
and conductive heat gain

25. SANGATH

26. Sangath
Thaltej Road,Ahmedabad
SANGATH means “moving together through participation”.
Ar. BALKRISHNA VITHALDAS
DOSHI

27. Location: Thaltej Road, Ahmedabad
380054
Client: Balkrishna Doshi
Architect: Balkrishna Doshi
Period of construction: 1979-1981(2yr.)
Project Engineer: B.S. Jethwa,
Y. Patel
Site area: 2346 m2
Total Built-up Area: 585 m2
Project Cost: Rs. 0.6 Million(6 crores )

28. •Cold northerly winds are
responsible for a mild chill in
January.
•Avg. Annual Rainfall: 800mm
•Highest temp. recorded: 48.5 °C
•The weather is hot from March to June
The avg. summer maximum is 43 °C
The avg. minimum is 24 °C
• From November to February,
The avg. maximum temperature is 30 °C
The avg. minimum is 13 °C
•Climate Type Hot and Dry

29. 1. Forecourt
2. Pond
3. Amphitheatre
4. Entrance court
5. Reception
6. Workshops
7. Conference
8. Toilets
9. Architects office
10. Subterranean
meeting room
11. Engineers
12. Design studio
13. Library
14. Studio
•Plan of studios

30. Ground floor plan
Library

31. FIRST FLOOR PLAN

32. SCEOND FLOOR PLAN

33. ROOF PLAN

34. ROAD
ENTRANCE COURATCOURATDESIGN STUDIOSERVICES
CONFEREN
CE
ACCOUNTS
SECTION AA
WEST ELEVATION

36. Sketch of “SANGATH “ by B.V Doshi
3D Modal of Sangath

37. •Design concept And Features:
1. Design concerns of climate ( temperature or sunlight).
2. Main studio partly bellow the ground (sunken).
3. Extensive use of vaults.
4. Very less use of mechanical instrument.
5. Special materials are used resulting in a low cost building
costing it.
6. Lot of vegetation & water bodies.
7. Continuity of Spaces.
8. Use of lot of diffused sunlight.
9. Complete passive design.
10. Grassy steps which Doshi uses as informal Amphitheatre.

38. •Earth berming
1. Main studio partly bellow the ground (sunken).
Section BB
Lounge Conference
2. Building is largely buried under ground to use earth masses for natural
insulation.
3. Earth sheltered structure reduced infiltration of outside air and the additional
thermal resistance of the surrounding earth considerably reduces the average
thermal load.

39. •Extensive use of vaults
•3.5 cm thick RCC
•8 cm ceramic fuses
•3.5 cm thick RCC
•6 cm thick water proofing
•1 cm thick broken China mosaic finish.
•Ceramics are temperature resistant.
•Broken China mosaic is insulative and
reflective surface.
•The rounded form of a hemispherical vault
(dome) has a larger surface area than its
base. Solar radiation is thus diluted and re-
radiation during the evenings is also greatly
facilitated.

40. Heat from the sun is reduced by grassy mounds and the
white reflective china mosaic that covers each vault.
•Reflecting outer surface

41. •Stack effect
Pressure
Pressure
• The warmer indoor air
rises up through the
building and escapes at
the top either through
open windows,
ventilation openings. The
rising warm air reduces
the pressure in the base of
the building, drawing cold
air in through either open
doors, windows, or other
openings and leakage.
•The greater the thermal
difference and the height of
the structure, the greater the
buoyancy force, and thus the
stack effect.

42. •Lighting
Indirect Lighting
oUpper Level Large
Openings-Facing
North.
oSkylights as projected
masses from the roof.
oSmall cut-outs on roof
slab filled with hollow
glass blocks.

43. •Design studios with smooth floors and rough textured vaulted ceiling interiors.
•The rough textured vaulted ceiling interiors in the main drafting room
dispersed natural light into the space(does not produce glare).

44. •Shading by vegetation
Minimizing Solar Radiation on South and West side : The structure is
closely integrated with the outdoor spaces. Vegetation on site is almost left
to grow into wilderness. The West and South façade is shaded by dense
trees.

45. •Maximizing Wind
Flow :
Wind from West and
South-West side is
taken in by just a
positioning structures
so as to create a
central open space
through which wind
can flow
unobstructed.
•Wind flow and building
form

46. Water Body:
• Water in the Sangath building is used as a major
modifier of the microclimate.
• Rainwaer and overflow of pumped water from the
roof tank are harnessed through roof channels that
run through a series of cascading tanks and water
channels to finally culminate in a pond from where it
is recycled back or used for irrigating vegetation.
•Water cascades also provide interesting visual
experiences.

47. Entry area fountain

48. Terraced court leading to main entrance areas; split level fountain

49.  A temperature difference of about 8°C
 Time lag for heat transfer is nearly 6 hours
 30% to 50% reduction in cooling energy
•Performance

50. THANKU YOU
PRESENTED BY:
CHETNA
4TH Sem