A short introduction about Hot and dry climatic study with case study ..........

1. HOT
N
DRY
SUBBMITTED BY-
PRAKHAR SINGH
SUBBMITTED TO-
AR. SONAL SINGH

2. PRAKHAR SINGH
3RD SEMESTER 2ND YEAR
BARN1AR19005
SOA ITM UNIVERSITY GWALIOR

3. • The hot and dry zone lies in the western
and the central part of India; Jaisalmer,
Jodhpur and Sholapur are some of the
towns that experience this type of climate.
• In such a climate, it is imperative to control
solar radiation and movement of hot winds.
• The design criteria should therefore aim at
resisting heat gain by providing shading,
reducing exposed area, controlling and
scheduling ventilation, and increasing
thermal capacity.
• The presence of “water bodies” is desirable
as they can help increase the humidity,
thereby leading to lower air temperatures.
• The ground and surrounding objects emit a
lot of heat in the afternoons and evenings.

4. • Appropriate orientation and shape of building.
• Insulation of building envelope.
• Massive structure.
• Air locks, lobbies, balconies, and verandas.
• Weather stripping and scheduling air changes.
• External surfaces protected by overhangs, fins,
and trees.
• Pale colours and glazed china mosaic tiles.
• Windows and exhausts.
• Courtyards, wind towers,and arrangement of
openings.
• Trees, ponds, and evaporative cooling.
Some of the design features for buildings in this climate
are:

5. Building Design Details
• Detailing building fenestration
design and construction details to
promote shading, insulation and
heat loss.
Materials
• Choosing materials which are
local, durable, utilize waste, have
low embodied energy content,
use less water for processing and
help insulate the building.

13. SHADING STRATEGIES
• Shading from the sun and well
designed shading devices are a
primary need in the hot-dry
climate. It is well established
that a majority of the solar heat
gain comes from radiation
through openings. When
designing shading devices for
windows, the required
horizontal and vertical shadow
angles need to be established.
They are dependent on both the
orientation of the window plane
and the sun path.

14. Horizontal shadow angle (HSA: characterizes
the vertical shading device)
• This is the horizontal angle between the
normal of the window plane or the wall
surface and the current sun azimuth angle.
It is relevant for designing vertical shading
devices such as fins.
Vertical shadow angle (VSA: characterizes the
horizontal shading device)
• This is the angle that a virtual plane
containing the bottom two points of the
wall/window and the centre of the Sun
makes with the ground when measured
normal to the window plane. It is required
when designing horizontal shading devices
such as overhangs.

15. Shading by single vertical shade
is not feasible as the shade
depth becomes prohibitive.
Hence the width is subdivided
and several louvers are
designed. If 6 divisions are
created, i.e. effective width to
be shaded is 250mm
Calculate HSA
and VSA at
different times
during
designated
period for each
facade. We
need to design
a shading
device for the
lowest possible
VSA (horizontal
shade) and the
lowest possible
HSA (vertical
shade)

16. Azimuth line (the sun’s position
vis-a-vis the north direction
Altitude lines (shows the sun’s
elevation over the horizon)
Lines showing the sun’s
movement on a certain day of
the year
Lines showing the hour of the
day on the day’s sun path

18. Wind-Rose Diagram-

19. Passive cooling-techniques-
Natural ventilation-
• Outdoor breezes create air movement through the house interior by the 'push-
pull' effect of positive air pressure on the windward side and negative pressure
(suction) on the leeward side.
•In order to have a good natural ventilation, openings must be placed at
opposite pressure zones.
•Also, designers often choose to enhance natural ventilation using tall spaces
called stacks in buildings.
•With openings near the top of stacks,
warm air can escape whereas cooler air
enters the building from openings near
the ground.
•The windows, play a dominant role in
inducing indoor ventilation due to wind
forces.

20. Wind tower-
•In a wind tower, the hot air enters
the tower through the openings in
the tower, gets cooled, and thus
becomes heavier and sinks down.
•The inlet and outlet of rooms
induce cool air movement.
•In the presence of wind, air is
cooled more effectively and flows
faster down the tower and into the
living area.
•After a whole day of air exchanges,
the tower becomes warm in the
evenings.
•During the night, cooler ambient air
comes in contact with the bottom of
the tower through the rooms.

21. EARTH AIR TUNNELS-
•Daily and annual temperature fluctuations
decrease with the increase in depth below the
ground surface.
•At a depth of about 4 m below ground, the
temperature inside the earth remains nearly
constant round the year and is nearly equal to
the annual average temperature of the place.
•A tunnel in the form of a pipe or otherwise
embedded at a depth of about 4 m below the
ground will acquire the same temperature as
the surrounding earth at its surface.
•Therefore, the ambient air ventilated
through this tunnel will get cooled in summer
and warmed in winter and this air can be used
for cooling in summer and heating in winter.

22. Evoporating cooling-
•Evaporative cooling lowers indoor air temperature by evaporating water.
•It is effective in hot and dry climate where the atmospheric humidity is low.
•In evaporative cooling, the sensible heat of air is used to evaporate water,
thereby cooling the air, which, in turn, cools the living space of the building.
•Increase in contact between water and air increases the rate of evaporation.
•The presence of a water body such as a pond, lake, and sea near the building
or a fountain in a courtyard can provide a cooling effect. A TYPICAL SECTION
SHOWING PASSIVE SOLAR FEATURES OF WALMI BUILDING,BHOPAL
•The most commonly used system is a desert cooler, which comprises water,
evaporative pads, a fan, and pump.

24. SANGATH ARCHITECTS STUDIO
Balkrishna Doshi's own studio, Sangath,
features a series of sunken vaults
sheathed in china mosaic as well as a
small grassy terraced amphitheater and
flowing water details. Having been
considered the building that fully
describes himself, Sangath is a complete
combination of Doshi's architectural
themes from his previous work including
complex interiors and structures,
ambiguous edges, vaults and terraces.
More about Sangath after the break.

25. PROJECT DETAILS-
• SANGATH means “moving together through participation.”
• It is an architect studio.
• Location- Thaltej road, Ahmedabad.
• Clint- Balkrishna Doshi sir.
• Period of construction- 1979-1981.
• Site area- 2346 meter square.
• Total build-up area- 585 meter square.
• Project cost- Rs. 0.6 Million (1981).

26. • The architectural studio comprising reception areas, a design studio, office
spaces, workshop, library, conference room, and other ancillary spaces has been
designed to naturally manage the forces of nature. •There are spatial,
constructional, and landscape responses to combat the vagaries of nature in the
hot dry climate.
• In Ahmedabad, the summer
temperature reaches 45 °C and the
heat is very intense.
• It is the heat rather than the
breeze that becomes critical.
• Natural comfort conditions can be
achieved by protecting spaces from
the heat and glare of the sun

27. DESIGN CONCEPT AND FEATURES-
•Design concerns of climate ( hot n dry).
•Extensive use of vaults.
•Main studio partly bellow the ground (sunken).
•Very less use of mechanical instrument.
•Special materials are used resulting in a low cost building costing it.
•Lot of vegetation & water bodies.
•Continuity of Spaces.
•Use of lot of diffused sunlight.
•Complete passive design.
•Grassy steps which Doshi uses as informal Amphitheatre.

28. Sandwiched construction of vault -
•With the help of movable formwork,
the vaults of “Sangath” were
constructed with hollow clay tiles
sandwiched into walls.
•Inexpensively purchased, the outer
skin is covered with broken glazed tile
pieces from a manufacturer’s waste
material.
•This procedure has a precedent in the
great Catalan architect Antoni Gaudi’s
benches of his Park Guell in Barcelona.
• Doshi’s use of this traditional
technique reduces the heat inside the
building

29. • So, not only is the re-use of waste material an important element
of Third World methodology, it is also one of the most efficient ways
to reduce the large percentage of sunrays.

30. Vaulted roof form -
• The roof form creates an efficient
surface/volume ratio optimizing
material quantities.
• The higher space volume thus
created provides for hot air pockets
due to convective currents that keep
lower volumes relatively cool.
• The ventilating window at upper
volume releases the accumulated hot
air through pressure differences.

32. SECTION-
PLAN-

33. Subterranean spaces -
•The building is largely
buried under the
ground to use earth
masses for natural
insulation.

34. Indirect/diffused light -
•Sun light brings heat and haze with it.
•To maximize daylight (intensity of illumination) and to
diffuse heat and glare, the light is received in indirect
manner by diffusing it.
•There are three ways by which natural light is drawn
within.
•By upper-level large openings towards north direction,
which is cool, and consistent light is reflected off the
clouds.
•Skylights, which are projected masses from the roof,
reflect the light on the white inner wall surface, which
further radiates light into the room.
•Innermost spaces are lit up through small cut outs in
the roof slab, which are then filled with hollow glass
blocks that take away the glare and transmit diffused
light .

35. LANDSCAPING-
• Lawns and vegetative
cover all around create a
favourable microclimate
by absorbing solar
radiation and providing a
cooler passage of air
through humidity.

36. Water channels
• Rainwater 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.

37. Use of secondary waste material -
• Paving material is a stone
chip waste while the roof
surface is glazed tiles waste,
both available as waste
material from factories at no
cost.
• These have been creatively
hand-crafted and integrated
into the design by fully using
waste material.
• The application is also skill-
oriented and involves as well
as promotes craftsmen and
our traditional heritage.

38. Performance -
•The above measures have ensured excellent climate control in terms of keeping
the inside cool and increasing the time-lag for heat transfer.
•There is a difference of about 8 degree C between the interior and exterior roof
skin temperatures. The time-lag for heat transfer is nearly six hours.
•The natural elements are harmoniously blended with the built environment, and
water recycling and waste material reuse have ensured cost economy as well as
environmental consciousness.