The document discusses principles of solar control and shading in building design. It explains that insolation, or solar radiation, has direct, diffuse, and reflected components that impact heat gain. Proper shading methods include orientation, trees/plants, building shapes, and exterior devices. Solar charts and shadow charts can be used to understand the sun's changing position and design effective shading. Techniques involve blocking solar rays during overheated periods while admitting them when additional heat is needed. Building typologies and exterior elements like overhangs, fins, and trees can provide strategic shading. Urban design also impacts shading through street orientation, compact forms, and landscaping.

1. Solar ControlSolar Control
Principles of Shading

2. InsolationInsolation
– The total Solar radiation/ Solar force/
– Components:
• Direct radiation from the sun
Diff d di ti f th k ( t h )• Diffused radiation from the sky (atmosphere)
• Reflected radiation from the ground & nearby
buildings.g
– The intensity of Insolation depends on
• The atmosphere and solar altitude (angle in degree)
• Trees/Vegetation
• Nature of the ground near the reference point
( fl ti )(reflective )

3. Paths of solar force (Insolation)Paths of solar force (Insolation)
• Through structure (materials)
– Indirect transmission (emission)
• Through glasses
– Direct transmission and emission (needs much
protection)
– green house effectgreen house effect

4. Solar ControlSolar Control
• Protecting the solar force away from building
surfacesurface
[Protecting solar force during overheated
i d/ i h f ]period/ in the afternoon]
• Admitting it during under‐heated period /
morning

5. Methods in solar controlMethods in solar control
• ShadingShading
– Shading external walls of buildings
– Shading glazed partsShading glazed parts
– Shading outdoor spaces

6. Ways of Achieving ShadingWays of Achieving Shading
1. Proper orientation (using sun chart)p ( g )
2. Trees/plants (types, distance)
3. Design of building volumes or shapes (Typology:
Zigzag, Court yard, protruding and recess forms)g g, y , p g )
4. Design of screens and shading devices (sun‐
breakers overhangs)breakers, overhangs)

7. Sun Control requires:Sun Control requires:
• Understanding the dynamic and seasonalUnderstanding the dynamic and seasonal
pattern of sunlight and shadow for the
purpose of annual shading
• Checking sun light penetration andChecking sun light penetration and
effectiveness of required sun controls using
graphic projections (sun path diagrams or sun
shadow chart)

8. Knowing how exactly the sun strikes a building helps
t i l l l tto precisely calculate:
– Proper orientation of a buildingProper orientation of a building
– Orientation, size and shape of individual windows
– The length of the effective overhang of a sun shadeThe length of the effective overhang of a sun shade
(horizontal)
– Depth of a fin (vertical shading elements)Depth of a fin (vertical shading elements)
– Angle of a solar collector
– The placement of treesThe placement of trees
– The placement of a court yard
– The length of the shadows cast by near by buildingsThe length of the shadows cast by near by buildings

9. Locating Sun’s Position and Angle of Radiationg g
Knowing the sun’s position for any time of the dayKnowing the sun s position for any time of the day
and any day of the year, to determine:
fThe over heated period of the year
The under heated period and
The over heated hours of the day
Th d h t d h f th dThe under heated hours of the day

10. Astronomer’s concept about earth‐sun
l i hirelationship
O th t t /24 h it i• Our earth rotates once/24 hours on its axis
• Our earth revolves once/year around the sunOur earth revolves once/year around the sun
• The earth’s axis of rotation is not
di lperpendicular
• As the earth orbits the sun, its axis always
remains tipped in the same direction

14. Designer’s ConceptDesigner s Concept
• Unlike astronomers designers think that theUnlike astronomers, designers think that the
sun moves about a fixed earth‐
Apparent sun motion

15. Change in seasons:Change in seasons:
• Equinox: Here the sun stands directly over the q y
equator, days and nights are exactly twelve hours
long
• Summer solstice: When the earth’s axis tipped
toward the sun (the sun is high in the sky)toward the sun (the sun is high in the sky)
• Winter Solstice: When the earth’s axis leans awayWinter Solstice: When the earth s axis leans away
from the sun (the sun daily path lowers and stops)

16. The term Solstice literally means the place where the
sun stands still. (Solar noon)
Dec Jan Feb Mar Apr May June
OVERHEA
D IN
ADDIS
WINTER
Dec Jan Feb Mar Apr May June
Dec Nov Oct Sep Aug July June
WINTER
SOLISTIC
E
EQUINO
X
SUMER
SOLISTIC
E

17. SUN’S POSITIONSUN S POSITION
• It is possible to locate sun’s position for everyIt is possible to locate sun s position for every
time of the day and every month of the year
using the following two angles:using the following two angles:
A = angle of altitude above the horizonA = angle of altitude above the horizon
B angle of bearing from the southB = angle of bearing from the south

18. Sun charts (solar charts)Sun charts (solar charts)
• Altitude (A) and Bearing (B) angles for everyAltitude (A) and Bearing (B) angles for every
time of a day and every month of a year
• Daily path of the sun for every month(21st)
• Also called sun‐path diagrams
• For a given latitude

20. ‘Solar noon’ in solar chart:Solar noon in solar chart:
• It is where the sun is exactly due south orIt is where the sun is exactly due south or
north. In this position it is easier to compute
the sun’s altitude The upper and lower curvesthe sun s altitude. The upper and lower curves
in solar chart show Sun path (cone of
revolution) at “solar noon”revolution) at solar noon .

21. Shadow ChartShadow Chart
A “Flag pole” Shadow paths taken at “solarA Flag pole Shadow paths taken at solar
noon” will give the same cone of revolution
but reversed for the sun position at the southbut reversed, for the sun position at the south
we will have shadow of “Flag Pole” at the
northnorth.

22. Orientation of buildings for shadingOrientation of buildings for shading
Optimum orientation gives:
• Maximum radiation (under heated period)
• Reduced radiation (overheated period)

23. Orientation…Orientation…
– East and west ‐‐‐least advantageousEast and west least advantageous
– South‐east and south‐west ‐‐‐reasonably
satisfactory
– South‐‐‐ the most advantageous
• Warming (winter)
• Cooling (summer)
h h– North‐South

24. Building typology for shadingBuilding typology for shading
• zigzag forms recessed verandaszigzag forms, recessed verandas
• Courtyards:
Shaded outdoor space for hot areasShaded outdoor space for hot areas,
patios with pool (trees, plants and water in the enclosed
space will cool the air by evaporation)p y p )
• Inward‐ looking house – smaller or few openings,
Solid forms
• Protruding forms

26. Shading DevicesShading Devices
• Overhangs
i l fi / b k• Vertical fins /sun breakers
• Sun‐breakers
– The most efficient
– Have got visual effects
– Various types

27. Sun‐breakersSun breakers
• Fixed sun breakers horizontal/vertical/ eggFixed sun breakers horizontal/vertical/ egg
crate
• Movable (shutter)
• Adjustable exterior lovers (metal/plastics)
• Curtain, Venetian blinds,

33. Trees for shadingTrees for shading
• Their type and distance
id• Deciduous trees
• Maximum shade during summer (hot)
D i h i l h i i l i i• Dropping their leaves when maximum insolation is
needed‐ during cold winter months

36. It i thIt i thIt is theIt is the
utilityutilityyy
polespoles
whichwhichwhichwhich
givesgives
charactercharacter
to mostto mosto oo o
streetsstreets

37. P lP lPeople arePeople are
waitingwaiting
for busfor bus
in thein the
hot sunhot sun
with nowith nowith nowith no
shadeshade

41. Shading requirement at Urban design
l llevel
• designing buildings to shade each other (compact
morphology)
• north – south residential streets are mostly shaded if
they are designed narrow and defined by storied
buildingsbuildings.
• Urban trees and plants have big importance for
shading, cooling and aesthetic value.shading, cooling and aesthetic value.