Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
INTRODUCTION
Sunlight passages into building impacts on the building energy utilization in a number of
ways and through hot and cold climates. In all seasons of the year, the sun improves
daylight quality and proper designed shading devices can appreciably lessen building cooling
load consumption and further enhance daylight utilization.
What type of shading device is best soothed for our buildings?
The shading requirements vary according to climate and building orientation. There is an
acceptable rule of thumb which suggests as shown below:
SUGGESTED SHADING TYPE
ORIENTATION
NORTH
fixed or adjustable shading placed horizontally above window
EAST & WEST adjustable vertical screens outside window
NE & NW
adjustable shading
SE & SW
Planting
Orientation is quite critical; some shading methods are extremely specific to compass
orientation (azimuth). For example, fixed horizontal shading may leak sunlight into the
building during the morning or afternoon unless it is used on a face that is oriented almost
exactly due south. The same is true of vertically oriented shading that is installed on east
and west faces.
Examples of Sun shading devices at the Oba Kekere Campus, Federal University of
Technology, Akure
The study area Oba kekere campus is located within Federal University of Technology,
Akure. It lies between latitudes 7o18′03′′N - 7o18′06′′N and Longitudes 5o08′02′′E - 5o08′05′′E.
The site is located within the sub-equatorial climatic belt with tropical rain-forest
vegetation. The mean annual temperature is 240C-270C, whiles the annual rainfall varies
between 1500mm and 3500mm (Adeleke and Goh Cheng Leong, 1978). The Federal
1
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
University of Technology, Akure is underlain by rocks of the Precambrian Basement Complex
of Southwestern Nigeria (Rahaman, 1989).
plate 1
Most building in Oba kekere campus are shaded using predominantly fixed shading devices.
Fixed, in this case, means attached to the building. It is acceptable for the shading device to
move and respond to solar angles, as louvers do.
The challenges with cost, energy generation and technology have made it impossible for the
designers of these buildings to specify such devices.
Installing fixed shading devices can be an efficient way to provide thermal and visual
comfort to building users. The design of fixed shading devices should depend on the daily
and yearly variation of solar position. This isn’t the case with most of the buildings in Oba
kekere campus.
2
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
The designers of these buildings have given proper consideration to their orientations; the
layout of most of them is North-South with the longer axis facing East-West. There are little
or no openings on the north-south elevations except for a few (Great Hall, etc).
A great number of these buildings are single bank with large fenestrations allowing for
adequate ventilation.
This exercise employed the use of Revit building information module to generate some of
the models (developing 3-dimensional blocks for the oba kekere buildings. See plate 2)
while subjecting them to the exact climatic conditions by in putting the latitude and
longitude for Federal University of Akure to generate the shading pattern at 12noon of 21
June 2011 for the various buildings.
Plate 2 (Please note the oval highlight)
3
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
Determining the azimuth for simulation is a big challenge! It will require knowing the actual
orientation of the building faces within an accuracy of about 10°. Therefore, all buildings
examined have been placed as shown in the location map in plate 1 and the latitude and
longitude applied as shown in Plate 2.
4
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
Oba Kekere buildings
1. Industrial Design Department Building
plate 3
The use of vertical fins, an “after thought” roof overhang and a projecting concrete canopy
at the entrance are the major shading element on this building.
plate 4
Revit simulation of IDD building showing the shading devices
Roof overhang: The shadow pattern shows that the “after thought” roof overhang of this
building is effective in keeping direct sunlight out of the windows. They can provide major
additional value in protecting the wall finish and reducing moisture problems
plate 5
Section through IDD building
5
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
2. The Post Graduate Hostel
plate 6
The design of the Post Graduate Hostel Oba Kekere employed the use of balconies and roof
eaves, doors and windows are set back deeper into wall sections while extending other
elements of the skin to visually blend with envelope structural features.
plate 7
Revit simulation of The Post Graduate Hostel building showing the effect of balcony as a
Shading device
plate 8
A section through the balcony
6
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
3. Prototype Staff Quarters
plate 9
The design of staff quarters in oba kekere employed varying combination of shading
devices. Vertical fins, eaves and insert of windows and entrance
Plate 10
Revit simulation of a prototype staff housing in Oba Kekere showing the effect of sunshading devices
plate 11
Section through the eaves
4. Oba Kekere bus-stop
7
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
plate 12
Oba kekere bus-stop. Shed concept have long been used as sun-shading devices.
plate 13
Revit simulation of sun-shading of the bus stop in Oba kekere
plate 14
Section through the bus-stop
8
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
5. Classroom Block at Oba kekere
plate 15
Inset windows of classrooms at Oba kekere
The shadow patterns show that deeply inserting windows are shaded from solar heat gain.
In effect, the roof acts as a shading device around the window. 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 useful space.
However, it can be effective if it is used properly, namely, on southerly exposures at low
geographic latitudes.
plate 16
Revit simulation of classroom in Oba Kekere
plate 17
Section of classroom
9
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
6. Laboratory Block at Oba Kekere
plate 18
Corridors and roof over-hangs are common shading techniques used in most Oba Kekere
buildings. Classrooms and Laboratories are designed in similar manner i.e. single banking,
cross ventilation and large fenestrations.
plate 19
Revit simulation of Laboratory building in Oba Kekere
plate 20
Section through the corridor
10
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
7. Electronic Test Centre
Plate 20
This building relies mainly on the eaves to provide sun-shading on the long side of the
building while the corridor provided shade for the entrance.
Plate 21
Revit simulation of Electronic Test Centre in Oba Kekere
plate 22
Section through the corridor
11
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
8. Great Hall
plate 23
Entrance into great Hall with concrete canopy, the roof eaves is not adequate to prevent
solar heat gain.
Plate 24
In the design of classrooms, laboratories and offices, it is well recognized that appropriate
solar shading devices can control indoor illumination from daylight, solar heat gains and
glare while maintaining the view out through windows, thus saving lighting and thermal
energy and maintaining visual comfort. Therefore, designers should have a thorough
understanding of the performance of shading devices to enhance the success of their
projects.
12
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
Nevertheless, the geometric aspects of shading design are rather complicated, especially if
one wishes to study alternatives or seasonal performance. A solid modeller like REVIT can
make things much easier.
13
Examples of Sun Shading devices at the Oba Kekere Campus, FUTA
REFRENCES
ISO. 2003a. Standard 15099: Thermal performance of windows, doors and shading devices detailed calculations. International Standard Organisation, Geneva, Switzerland.
ISO. 2003b. Standard 9050: Glass in building-determination of light transmittance, solar
direct transmittance, total solar energy transmittance, ultraviolet transmittance and related
glazing factors.
K.N. Agarwal* and V.V. Verma* (2003) Thermal characteristics of glazing and shading
materials
Laouadi A., Galasiu A.D. 2009. Window shadings reduce residential cooling energy. Solplan
Review; 144. pp. 18-19.
Laouadi A. 2009a. Thermal performance modelling of complex fenestration systems. Journal
of Building Performance Simulation, 2(3), pp. 189 — 207.
TPUB (2006 ) Example of architectural shading devices. Retrieved November, 2009
www.tpub.com
14