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Familua O. S. ARC/05/5609 Page 1
AN
ASSIGNMENT
ON
TYPES OF SUN SHADING DEVICES IN
NIGERIA
PREPARED BY
FAMILUA O.S.
ARC/05/5609
SUBMITTED TO
DEPARTMENT OF ARCHITECTURE
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR
THE AWARD M.TECH IN ARCHITECTURE
FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE.
AUG, 2011
Familua O. S. ARC/05/5609 Page 2
INTRODUCTION
Well planned external shading is the most effective method of reducing solar heat gain. In
addition, it offers possibilities for incorporating day lighting and passive heating. Some types of
external shading interfere with view, while other types make it possible to exploit view that
would otherwise be impossible because of solar glare.
External shading is much easier to integrate into the design of a new building than it is to
retrofit. External shading has a major effect on the appearance of the building, and it must be
anchored strongly to the building structure to resist wind loads. In retrofit, both of these factors
are serious challenges.
Each face of a building requires a different shading treatment because sunlight strikes each
side from different angles. A south face is best shaded with horizontal shading. East and west
faces require shading that blocks sunlight entering at low angles. A north face can often be left
unshaded.
Shading can be adapted to virtually all sizes of windows and skylights. The most common
limitations are high cost and the effect on the building’s appearance.
Effective external shading blocks all or most direct sunlight, although it admits indirect light
from the sky. It typically reduces solar heat input by 80% to 90%. In buildings where solar load
dominates the cooling requirement, shading may reduce a building’s total cooling load by as
much as half.
All interior systems are less effective than a good exterior system because they allow the sun’s
heat to enter the building. They also depend on user behavior, which can’t be relied upon.
LIMITATION
This study seeks to identify various types of sun-shading devices available in Nigeria.
Shading and daylighting.
East, west and south building facades call for a different approach to solar control. The high
summer sun is partially blocked by horizontal aluminum shading device on the south façade
(Figures 1).
Familua O. S. ARC/05/5609 Page 3
Shading on the south façade prevents direct solar radiation from high altitude sun from
penetrating the building envelope during critical times of the day.
East and west facades use a perforated Venetian blind within the glazing cavity to provide
needed shading.
The shading device also serves as an external lightshelf by reflecting light onto the ceiling near
the window. The standard ceiling height is 9 ft [2.8 m] and the ceiling in office areas near the
window angles up toward the window to maximize daylight in the work zone. The low altitude
of the sun on the east and west facades during the early morning and late afternoon demands
almost 100% blockage. In response, motorized blinds are installed within the triple-glazing
system on the east and west facades and are controlled by light sensors.
Familua O. S. ARC/05/5609 Page 4
Types of Sun-Shading Devices
Basically there are three type of sun-shading devices in Nigeria, viz;
Horizontal devices
Vertical devices
Egg crate devices
Horizontal devices: This is the most suitable for overhead sun. They are best suited southern
and northern elevation and their performance is measured by vertical shadow angle. The simplest
form is a roof overhang, a projecting floor,or a projected balcony.
Shading Methods
Sun-Shading is a general technique that you can accomplish with many different types of
architectural features. Shading may be fixed or movable.
Familua O. S. ARC/05/5609 Page 5
Projecting horizontal shelves.
These can be a primary method of shading south faces. They must be built into the building’s
structure, and hence they are limited to new construction. To be effective, they must be much
wider than the windows, in the direction along the wall, to account for the sun’s motion from
east to west. Typically, they are installed above the level of the windows, If the windows are
closely spaced, shelves typically are installed along the full width of the south face. Smaller
shelves can also be built into tall windows at various levels.
Adun House Ilorin kwara state
Familua O. S. ARC/05/5609 Page 6
Balconies.
These have the same effect as horizontal shelves, but more so. They are deep enough to provide
significant shading even if they do not face in a southerly direction. They provide major
additional value as usable space and as an ambiance feature.
Private Hospital Ilorin kwara state
Familua O. S. ARC/05/5609 Page 7
Eaves and overhangs,
Which can provide effective shading for the floor level directly under the eave. They merit
strong consideration as shading devices, and they can provide major additional value in
protecting the wall finish and reducing below-grade moisture problems.
Staff Quarter Kwara Poly, Ilorin kwara state
Familua O. S. ARC/05/5609 Page 8
Awnings
Awning which project downward over the windows. These may be fully effective on south faces,
and provide partial shading of windows on east and west faces. A common mistake is making
awnings to fit the width of the window. Such awnings are too narrow, allowing an excessive
amount of sunlight to enter from the sides.
Residential Building Ilorin kwara state
Familua O. S. ARC/05/5609 Page 9
Horizontal shelves integrated with windows
These are effective cooling load control devices on a south face. Otherwise, they are mainly a
decorative touch. This building must be at southerly latitude for shelves this shallow to provide
much benefit.
Works Department Kwara Poly, Ilorin kwara state
Familua O. S. ARC/05/5609 Page 10
Vertical devices:
This is the best shading for low sun. They are commonly referred to as fins and are most
effective on western and eastern elevation. Their performance is measured by the horizontal
shadow.
Vertical array of louvers
These provide effective shading of full-height windows across a narrow walkway. They are high
enough to avoid obstructing the view.
Sterling Bank Building Ilorin kwara state
Familua O. S. ARC/05/5609 Page 11
Inset windows.
In effect, the entire wall acts as a shading device around the window. This is obviously a feature
that is limited to new construction. It is usually done as a stylistic element, rather than as a
rational approach to controlling sunlight. As a method of shading, it is very expensive and
wasteful of occupiable space. However, it can be effective if it is used properly, namely, on
southerly exposures at low geographic latitudes.
Lecture Theatre Kwara Poly, Ilorin kwara state
Familua O. S. ARC/05/5609 Page 12
Fixed louvers
It may be useful on any exposure of a building, except north. The best orientation for the louver
blades depends on the direction that the glazing faces. On the south side, the blades should be
horizontal. For the north side, louvers are vertical. For other directions, they may be tilted.
Louvers can be arranged in a horizontal array, like a shelf. Or, they can be arranged in a vertical
array, like a venetian blind. Or, they can be installed at an angle, like an awning. Louvers
interfere with the view if they are installed in the line of sight, but they may not block the view
entirely. For example, a vertical stack of horizontal louvers in front of a window interferes with
the view upward and horizontally, but they are not too bad when viewing downward.
Obafemi Awolowo University Health Center Ile Ife
Familua O. S. ARC/05/5609 Page 13
Vertical fins
Fins are useful for shading north faces from summer sunlight early and late in the day. Figure
below shows a building with fins molded into the wall surface.
Computer Centre Kwara Poly, Ilorin kwara state
Familua O. S. ARC/05/5609 Page 14
Miniature fixed-louver materials
These are supported in frames and installed directly over glazing. They are useful on all faces.
One product is made from aluminum sheet punched to create tiny louvers. Another product
consists of tiny bronze strips woven into a louver with wires. Within limits dictated by the
manufacturing process, the manufacturer may offer a variety of louver spacings and tilt angles.
Some fixed louver materials can be oriented vertically for use in east-west shading, or to any
other angle.
Kwara Hotel Ilorin kwara state
Egg crate devices:
Familua O. S. ARC/05/5609 Page 15
This is the combination of vertical and horizontal devices. This type exclude more radiation than
either vertical or horizontal element alone. They are usually in the form of grill blocks or
decorative screens. Their performance is determined by both the horizontal and vertical shadow
angle.
Egg crate decorative Screen
The egg crates block sunlight from all directions. They are attached to the wall. This rather
massive construction and the irregular placement of the screen may have been motivated by an
appearance concept as much as by sunlight control.
University of Ibadan Health Centre, Ibadan
DESIGN STRATEGIES
• Use exterior shading, either a device attached to the building skin or an extension of the skin
itself, to keep out unwanted solar heat. Exterior systems are typically more effective than interior
systems in blocking solar heat gain.
• Design the building to shade itself.
If shading attachments are not aesthetically acceptable, use the building form itself for exterior
shading.
Set the window back in a deeper wall section or extend elements of the skin to visually blend
with envelope structural features.
• Use a horizontal form for south windows.
Familua O. S. ARC/05/5609 Page 16
For example, awnings, overhangs, recessed windows .Also somewhat useful on the east and
west. Serves no function on the north.
• Use a vertical form on east and west windows.
For example, vertical fins or recessed windows. Also useful on north to block early morning and
late afternoon low sun.
• Give west and south windows shading priority.
Morning sun is usually not a serious heat gain problem. If your budget is tight, invest in west and
south shading only.
• Design shading for glare relief as well
Use exterior shading to reduce glare by partially blocking occupants’ view of the too-bright sky.
Exterior surfaces also help smooth out interior daylight distribution.
• If interior devices are the only shading, specify light colors
In order to reflect the sun’s heat back out. Light-colored blinds or louvers are best. Light-colored
woven or translucent shades are acceptable, but may not control glare under bright summer
conditions.
• Use devices that still allow daylight in
Blinds and openweave shades are good choices for filtering but not blocking all light.
• Interior shading alone has limited ability to control solar gain.
REFERENCES
D. R. Wulfinghoff, 1991 Reducing Cooling Load: Window and Skylight
Familua O. S. ARC/05/5609 Page 17
Laouadi, A. 2010, Guildlines for Effective Residential Solar Shading Devices. National Research
Council Canada
K. O. Kadari and J. Okosun 2006 Thermal Performance in Building Without Shading Devices,
Journal of Applied Science
Ogunsote O.O. 1991 Introduction to Building Climatology. A basic course for Architecture
students. First Edition, Ahmadu Bellow University Press Limited Zaria Nigeria
Olufowobi M. B. 1987, A Simple Approach to the design of effective horizontal shading device.
Nigeria Institute Of Architect