TECHNICAL REPORT ON

RECOMMENDED SUN-SHADING OF EASTERN ELEVATION IN AKURE

BY ADANIKIN OLUMIDE AYODEJI

(ARC/05/5570) SUBMITTED TO

The Department of Architecture School of Post-Graduate studies

Federal University of Technology Akure, Ondo State

Nigeria

Lecturer, Prof.O.O Ogunsote

AUGUST2011

TABLE OF CONTENT

Abstract 2

1.0 Introduction 3

1.1 Importance of Akure Town 4

1.2 Geographical Location of Akure 4

1.3 Geology and Vegetation 5

1.4 Description of process of Data collection 6

1.4.1 Source 6

1.4.2 Time

2.0 Sunshine in Akure 7

2.1 Solar radiation 7

2.2 Long wave radiation heat loss 8

2.3 Design of sun shading devices 8

2.4 How to shade eastern elevation 9

2.5 Sun control 9

3.0 Sun-shading and design recommendations for eastern elevation in akure. 10

3.1 Landscaping 10

3.2 Roof overhangs 10

3.3 Interior and exterior shading. 11

4.0 Conclusion 13

References 14

LIST OF TABLE

Table 1.0 Climatic data sheet

Table 2.0 sunshine graph

ABSTRACT

Historically architectural forms have largely resulted from man struggle with adverse climatic

condition. Today, in our technological age, we have been able to make any area of planet

habitable since interior and exterior climatic control can be achieved by way of natural/ artificial

heating and cooling system. This advancement in construction technology has contributed to

worldwide uniformity of architectural and disappearances of district/ regional types of housing.

The need for better environmental condition is one of the major reasons for the existence of the

building. The apparent human environmental requirements are for lights, air and warmth in

addition, sound must be considered since it is indispensable in every activity. For comfort and

efficiency, the human body requires a moderate rate of environment condition.

This report contains a detailed recommendation of sun shading for eastern elevation Akure; the

primary data was collected from the Ondo State Government Agro-climatological. The data was

use as bases for analyzing the architectural problems and design recommendation for eastern

elevation in Akure.

Keywords: Sun-shading, Eastern elevation, Sunshine, Akure, Nigeria

CHAPTER ONE.

1.0 INTRODUCTION

Akure lies in the tropical zone; solar heat, glare and humidity are its characteristics. The

area is particularly noted for dry and wet season, a tropical climate characteristically defined by

the wet Southwest and dry Northeast trade wind

There is need to control the amount of sunlight that is admitted into a building, in warm,

sunny climates excess of heat gain may result to high cooling energy consumption. Well

designed sun shading devices can considerable reduce building peak heat gain and requirement

and improve the natural lighting quality of building interior depending on the amount and

location of fenestration. It can also improve user visual comfort by reducing contrast ratios.

Shading devices offer the opportunity of differentiating one building facade from another.

1.1 IMPORTANCE OF AKURE TOWN

Akure is the capital city of Ondo State in Nigeria. A state with an area of 20. 555 square

kilometer. Osun, Ogun and Ekiti states at the west, Kwara and Kogi at the North, Edo and Delta

at the East and at the southern part by the Atlantic Ocean, bound it.

Topographically, the land rises steadily from the shores of the Atlantics Ocean to the

giant highlands of the Akoko’s in the North. These highlands which are part of the famous

Yoruba highlands of western Nigeria constitutes a great water shed from where most of the

notable rivers draining Ondo state take their source. River Owena, which supplies water for

domestic use to one – third of the inhabitants of the states, is the most prominent amongst the

rivers. The importance of this river is seen in its usage in the various government establishments

and enterprises which includes, Owena motel, e t c. The latest national population census in 2006

but the figure at 360268 people (Information bulletin Ondo state, Dec 2006). The current

population of the city according to GeoNames geographical database 420594 people.

The federal ministry of communication, the police headquarters, the federal ministry of

trades and industries, the water corporation and the Power Holding Company of Nigeria

(PHCN). The establishment of Ondo State in February 1976 has since led to the establishment of

many ministries and statutory co- corporations as well as quasi-governmental institutions that

had greatly influenced the demographic structure of the city. Religious wise, the city serves the

headquarters for many Christian denomination inducing the Catholic Diocese of Ondo, the

Anglican Diocese of Akure, a district headquarters for the C.A.C church and the General

Headquarter for Agape Christian Assembly etc.

Also, Akure is the host city of educational institutions like, the federal University of

Technology, State school of Nursing and school of Midwifery as well as the school of Health

Technology.

1.2 GEOGRAPHICAL LOCATION OF AKURE

Akure lies on latitude 70 151 North of the Equator and on longitude 50 151 east of the

Greenwich meridian. It stands on the altitude of about 396 meters above the sea level. The land

towards Ado-Ekiti is hilly and studded with granite formations believed to be of volcanic origin

spreading over an area of 99,287 square kilometers, Akure is situated 210 kilometers east of

Ibadan, the capital of city of Oyo state, 168 kilometers west of Benin the capital of Edo state,

311 kilometers north east of Lagos, capital of Lagos, 189 south East of Ilorin the, capital of

Kwara state.

In relation to all big towns in state, Akure is centrally located, being surrounded with a

48-kilometer radius by those important towns. It is bounded by Ondo and Idanre to the south,

Owo to the east, Iju / Itaogbolu to the north and Ile-oluji to west.

1.3 GEOLOGY AND VEGETATION

Geologically, Akure falls into the pre-Cambrian exposed order granite belt. Its formation

dates back to as for as 600 to 3500 million years ago. Topographically, the site is generally flat

and soil area generally falls into large quantity of red laterite and very little of mangrove swamp

soil of Humid tropical Equatorial area.

Climatically, Ondo state has a tropical climate and belongs to the equatorial rain forest

belts. There are several attractive varieties of vegetations in Ondo state. Numerous creaks and

lagoons, bordering the Atlantic Ocean, are naturally separated one from another by mangrove

swamps of raffia swamps.

After this lies the well-drained rain forest region, which stretchers to about two hundred

kilometers inland. This zone provides that most fertile agricultural lands. The major cash is

cocoa, which provides about 90% of the annual revenue of Ondo state,

Timber is another important source of wealth of the rainforest belt and includes Iroko,

Mahogany, Obeche, Danta, and Opepe etc.

Lastly there is the Guinea savannah forest, which fringes the northern part of the state.

Farmers in this area concentrate more on the cultivation of subsistence crops such as cassava,

yams, maize, rice, cocoyam etc.

Akure town and neighboring ones like Idanre, Ondo, Ile-Oluji and Owo falls into second group

i.e. the equatorial rainforest.

1.4 DESCRIPTION OF PROCESS OF DATA COLLECTION

1.4.1 SOURCE

The information in this write up was collected from the Ondo state government Agro

climatological and ecological monitoring unit (PMU), Akure. Also other sources of data include

textbooks, Journal and Internet.

1.4.2 TIME

The data was collected at Automatic weather station of PMU unit Akure. The data was

recorded automatic recordable machine at appropriate time interval depending on the sensors

setting.

CHAPTER TWO

2.0 SUNSHINE IN AKURE

Akure being located in the equatorial zone has predominant climatic characteristics of being

warn humid, with little seasonal variation with sunshine among the climatic features that affects

human comfort others include rainfall, temperature, Relative Humidity and wind.

The effect of sunshine is in influenced by the humid-south west trade wind with rate of

cloud coverage. Akure lies in latitude 7’14N and Longitude 5, 17’E, the latitude is the factor that

determines the level of sunshine. Akure the state capital of Ondo state justifies her name being

called the sunshine state, it is called the sunshine capital, the sunshine duration in Akure

sometimes spans for almost 8 hours per day, as at last year dry season, the sun rises at 10:00am

and sets at 4:50pm, in 2010, this shows clearly that the level of solar radiation in Akure has

increased over the years.

Akure experience a vertical solar insolative mid day sun with a much concentrated solar

insolative, from the table, the month of September records the highest duration of sunshine for

8.7 hours, the implication of this is that the heat during the day is absorbed during the day and

during the night there will be emission of heat, the interior becomes unbearable, there is a need

for sun shading devices to exclude sun throughout the year and also utilizing landscape

design(use of landscaping vegetation, use of building fabric and design in the interior, and the

use of passive technologies for cooling,heating,ventilation and lighting)

2.1 SOLAR RADIATION

Solar radiation is an electromagnetic radiation from the sun. The wavelength of the solar

spectrum on the earth surface ranges from 0.28 microns to 3.0 microns; where a micron is a

thousand of a millimeter. The solar spectrum is divided into three;

i. The Ultra Violet (U.V)

ii. The Visible

iii. The Infra – Red (I.R)

Only the small section of the spectrum between 0.4 and 0.7 microns is light visible to the

eye; waves shorter than 0.4 microns are ultra violet radiation and waves longer than 0.76 microns

are infra red. Although the peak intensity of solar radiation is in the visible range, over one half

of the energy is emitted as infra red radiation.

2.2 LONGWAVE RADIATION HEAT LOSS

Longwave radiation is emitted by the surface of the earth to the atmosphere and to the

outer space. According to the Stefan Boltzmann law, the intensity of emitted radiation is

proportional to the difference between the fourth powers of the absolute temperature, zero Kelvin

of the emitting absorbing points.

It therefore depends on the difference between the temperature of the earth’s surface and

the absorbing medium atmosphere and outer space. Long wave radiation is also emitted in all

direction by the gases in the atmosphere; of this the earth absorbs the downward component

2.3 Design of sun shading devices

When are designing shading devices for a structure, especially in the eastern elevation (this is

been referred to the side at which sunrise). Therefore in designing the shading device for this

elevation, the following steps needs to be put into consideration;

We determine the time when shading is required in the year.

Position of the sun at the times shading is required must be established.

Also the dimension and the proportion of the shading device that will provide shading

during the period of shading are also determined.

Also the design of the device in terms of its geometry, aesthetics and structural

factors is also to be done

2.4 How to shade eastern elevation

Since the sun angle in the morning starts at 0 degrees (sunrise), we will be unable to block all

sunrise entering the building without blocking the view of the occupants. The best way is to

block the sun from 10:00 am – noon in the cooling season, while admitting this sun during the

heating season. Use interior blinds or shades to blocks glare for the occupants. This will allow

the heat gain to enter the interior space during the heating season thereby gaining the energy

benefits.

2.5 SUN CONTROL

Sun control or shading is the process of controlling the sunlight entering the building

which can be accomplished through a number of methods this depends on the use of space and

the climate. The use of sun control and shading devices is an important aspect of many energy

efficient building design strategies. In particular, building that employ passive solar heating or

daylight often depend on well designed sun control and shading devices. The sun shading

includes; vertical, horizontal e.t.c and they perform the following function; ventilation, allowing

a view out, protection from rain, protection from direct solar radiation and also from sky glare.

CHAPTER THREE

3.0 SUN-SHADING AND DESIGN RECOMMENDATIONS FOR EASTERN

ELEVATION IN AKURE.

Sun control or shading is the process of controlling the sunlight entering the building which can

be accomplished through a number of methods this depends on the use of space and the climate

For this technical report, the categories of shading am going to recommend include;

Landscaping

Roof overhangs

Interior and exterior shading.

3.1 Landscaping

In cooling and heating climate, deciduous trees works best on the east elevation of the

structure. Effective on this location, when they are well placed at a distance from the building

and with low crown. Evergreens are also effective in shielding the building from hot winds in the

eastern part of the building. Also, deciduous trees with long lasting foliage can be used to shade

all windows from direct sun penetration in the east elevation. Also ground covers around the

building will helps to reduce glare. All this are useful in the eastern part of the building not only

for their geometric form but they are also aesthetically pleasing and can create usable outdoor

spaces for occupants.

3.2 Roof overhangs

They are more reliable and less expensive form of shading because of they are part of the

building shell. They are to be designed to block the sun in heating climates, overhang, when

wants to be used to shade the eastern elevation must be designed for the orientation in each

months and also when the sun is lower in the sky.(that is when the temperature is higher ) to

provide shading on the eastern elevation.

3.3 Interior and exterior shading.

Exterior shading provides more effective shading at reducing unwanted solar gain than

interior shading because it stops the sun from striking the building. It can be fixed or movable.

They include; solar screens, roll down blinds, horizontal louvers, shutters and vertical louvers.

Interior shading tends to be less effectives at reducing cooling loads because they allow the sun

to enter the building, trapping the heat between the window and the shading devices. The interior

are of low cost and easy to operate and design. It can also be effective if designed to provide both

sun-shading and insulation during the day in the cooling season and at night in the heating

season.

Also points to notes when recommending a sun-shading for eastern elevation include;

The use of the space

Location of the building

Orientation

Also, to minimize the east glazing of the building

Window to be used in the eastern elevation must be of low heat gain coefficient.

The heat capacity of the building should be as low as possible in order to prevent accumulation

of heat during the daytime, which would elevate the indoor temperature during the night when

the external wind speed is usually at its lowest.

Thermal resistance of the external walls is advantageous within certain limits in minimizing the

heat flow the external surface warmed by the sun.

Modern insulating material, which, combine very low weight and heat capacity together with

high thermal resistance, may provide the best indoor climatic conditions.

Lightweight roofs, covered with tiles or sheets of asbestos cement or aluminum, are preferable in

a warm –wet climate owning to their low heat capacity.

When concrete roofs of high heat capacity are constructed, it is preferable to provide an

insulating lager below the ceiling, thus reducing heat flow during the day and enabling rapid

lowering of the ceiling temperature during the night.

4.0 CONCLUSION

It is high time for the architects to pay adequate attention to shading; this will go along

way in helping to reduce the amount of sun entering into the building and also friendly

architectural design for the city of Akure which is the main focus in this term paper.

Understanding of the building orientation, the choice of material and when to shade will

improves structural stability and functionality of buildings and determines the comfort of the

occupants.

REFERENCES

Fadamiro, J. A. and Ogunsemi, D. R. (1996) “Fundamentals of Building

Design, Construction and Materials”. Fancy Publications Ltd. Ile-Ife.

Ogunsote O.O (2011), Lecture Note on Applied climatology for Masters Students, Federal

University of Technology, Akure.

The Nigerian Meteorological Agency Departments of Civil Aviation,

Federal Secretariat, Igbatoro, Akure, Ondo State.

www.google .com www.ask.com

Year ; Lat & Long Nomogram Normalcloting

ET or CET Comfort limitsLocationAkure

Lower ; 22 C Upper ; 27 C

Notes; air velocity assumed

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DECMean air velocity (m/s)

0.92 0.96 1.25 1.27 1.09 1.15 1.35 1.09 0.91 0.72 0.62 0.52

Mean maximum DBT ( C )

30.72 33.67 31.53 31.55

30.64 30.55 28.19 28.59 29.76 31.00 30.13 33.27

Mean min RH(%)

30.3 30.2 56.2 53.9 55.4 59.5 64.6 65.5 64.6 61 52.7 48.3

Mean max WBT ( C )

23.32 21.72 23.99 22.37

23.65 22.85 21.30 22.28 23.28 24.19 24.05 23.99

Maximum ET ( C )Mean min DBT ( C )

26.62 28.34 28.21 27.4 27.18 26.42 23.39 23.71 24.31 27.00 27.88 28.21

Mean max RH (% )

73.27 57.84 89.63 74.00

75.29 74.30 84.92 88.17 85.05 79.29 71.97 70.11

Mean min WBT ( C )

15.62 14.85 16.27 15.00

15.45 16.27 17.54 18.00 18.30 20.08 20.70 20.69

Minimum ET (C )Hours of sunshine

7.6 8.3 8.5 7.3 8.3 7.2 8.5 7.9 8.7 7.3 6.4 6.8

Shading stop

Table 1.0 CLIMATIC DATA SHEET FOR AKURE IN THE YEAR 2004

Sunshine hours

(h/day)

TABLE 2.0 SHOWING HOURS OF SUNSHINE IN GRAPH

Source: The Nigerian Meteorological Agency, Department of Civil Aviation Federal Secretariat, Igbataro, Akure, Ondo State.