Thesis on building energy by abdelwehab yehya Bsc. in architecture

EiT-M
Energy Efficiency in Buildings
Energy Conservation and Energy Wastage Reduction in High-rise Buildings
of Addis Ababa
A BSc. thesis Submitted to the School of Architecture and urban planning, in partial fulfillment for the
award of a Bachelor degree in Architecture
Author: Abdelwehab Yahya
Advisor: Andrej Dosen (March)
Academic year 2014/15
February 2015
Ethiopian institute of Technology – Mekelle
የኢትዮጵያ ቴክኖሎጂ ኢኒስቲትዩት - መቀለ
Mekelle University
መቀለ ዩኒቨርስቲ

Energy Efficiency in Buildings
In the case of Addis Ababa High-Rise Buildings
By
Abdelwehab yahya Mohammed
A thesis submitted in partial fulfillment of
The requirement for the degree of
BACHLOR OF SCIENCE IN ARCHITECTURE
Ethiopian Institute of Technology – Mekelle
School of Architecture
Feb.13, 2015 GC

This thesis project; submitted to the School of Architecture and urban planning; Ethiopian Institute of
Technology – Mekelle (EiT-M); Mekelle University in partial fulfillment of the requirements for the
Bachlor degree in architecture.
Title of Thesis: Energy Efficiency in Buildings
Author: Abdelwehab Yahya Mohammed
Date: Feb 13 2015
Approved by Board of Examiners:
_______________ _______________ ________________
Advisor Signature Date
_______________ _______________ ________________
Examiner 1 Signature Date
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Examiner 2 Signature Date
_______________ _______________ ________________
Thesis Coordinator Signature Date

Enhancement of energy consumption and energy wastage of high rise buildings
[i] Student: Abdelwehab Yahya
Advisor: Andrej Dosen, MArch
School of Architecture and Urban Planning
TABLE OF CONTENTS
ACKNOWLEDGEMENTSI
ABSTRACT II
I
TABLE OF CONTENTS III
CHAPTER ONE - INTRODUCTION
1.1 The Study Overview 1
1.2 High-rise Buildings in Addis Ababa 1
1.3 Challenges of High-rise buildings in Addis 1
1.4 Objectives of the Research 2
1.5 Research /Hypothesis 3
1.6 Over View of the Research Process/Methodology 4
CHAPTER TWO - LITERATURE REVIEW
2.1 General 5
2.2 6
2.3 7
2.4 Benefits of Energy Efficiency in Buildings 9
2.5 The Effect of Urban Heat Island effect in Addis Ababa (case study) 11
2.6 Urban Expansion in Addis Ababa 12
CHAPTER THREE – THE RESEARCH DESIGN AND METHODOLOGY
3.1 The Study Approach 14
3.2 The Research Type 14
3.3 14
3.4 14
3.5 Research Methodology of Analysis 15
3.6 15
3.7 15

[ii] Student: Abdelwehab Yahya
CHAPTER FOUR – ANALYSIS AND FINDINGS
4.1 17
4.2 Results 19
4.3 Discussion 25
CHAPTER FIVE – CONCLUSION AND RECOMMENDATION
5.1 Principles of energy conservation in high-rise buildings 27
5.2 Conceptual design recommendations 28
5.3 Municipality rules re on 39
5.4 Conclusion 40
REFERENCES 41

[iii] Student: Abdelwehab Yahya
Acknowledgement
Reducing energy wastage in cities helps to have healthy environment. Conserving energy used by high-rise
buildings helps to have comfortable environment for the community and positively contribute for the country
development. As the aim of this research is creating comfortable environment with the help of architectural
design of our buildings this research was in need of cooperation from different ministries and experts.
For the success of this research based thesis there are a lot of ministries and professional experts who
positively contributed, gave accurate data and provided quantitative information from their sector. Their
contribution was very significant to come up with realistic and applicable solutions for identified problems.
Below are the lists of ministries and professional experts to be greatly acknowledged for their contribution:
National Meteorology Agency, Central Statistics Agency, Addis Ababa city Administration, Ministry of Urban
Development, National Energy Authority, Mekelle University School of Architecture and Urban Planning.
Appreciation and thanks to Mr. Andrej Dosen (MArch) advisor of the research, Mr. Semere Zeru, coordinator
of the study, Miss Sara Amare, head of the School of Architecture, Mr. Birhane Weldegebriel, manager of the
Central Statistics Agency Shire Branch, and of all whom showed their willingness to help during the study.

[iv] Student: Abdelwehab Yahya
Abstract
This study mainly focuses on the influences of high-rise buildings and the relationship between buildings and
environmental issues. This study’s main aim is the preservation of energy and minimizing the energy wastage.
The wastage in energy and the consumption of energy entirely studied. The interconnection of energy and
buildings indicates that buildings are responsible for the change in climate and embarrassment of the urban
areas. Studying the energy consumption and energy wastage leads to the design and building regulation
proposals of the study.
The more detailed study was made on the consequences of energy wastage and energy consumption of high-
rise buildings analysis. The analysis result and discussion give a clue for the proposal of the study more on the
architectural design solutions.
This study focuses in the city of Addis Ababa as the capital city the country with fastest urbanization rate
comparing to the regional metropolitan cities. The study tries to make reasonable architectural solutions for
the urban challenges which Addis Ababa faced now. This study mainly focuses on the architectural part of the
buildings to conserve energy and minimize energy wastage, but also some engineering solutions proposed as
alternative solutions for the challenges.
Finally the study provides proposals and recommendations on the enhancement of the energy consumption
and techniques to reduce the energy wastage and its consequences. Design approaches proposed for healthy
and productive working environment design. Improving the energy sustainability of high-rise buildings of
Addis Ababa in general addressed.
Key words; Energy Wastage, Energy Consumption, Energy Efficiency, Urban Heat Island Effect, Urbanization

[1] Student: Abdelwehab Yahya
CHAPTER ONE - INTRODUCTION
1.1 The Study Overview
Ethiopia is one of the developing countries in the horn of Africa region, which aims to achieve middle-income
status by 2025 while developing a greenery economy. Following the conventional development path would,
among other adverse effects, result in a sharp increase in GHG emissions and unsustainable use of natural
resources (URAdapt: Managing water in the urban-rural interface for climate change resilient cities). To avoid such negative
effects, the government has developed a strategy to build a green economy. In this proposal, the energy
consumption and wastage level of the high rise buildings of Addis Ababa will be analyzed. One of the needs
for the green economy strategy is the sustainability of energy, which needs buildings to be not only energy
consumers but also should be sources of energy generating.
1.2 High-rise Buildings in Addis Ababa
Addis Ababa as a capital city of the country and the center for big continental institutions like AU, having
embassies of different countries of the globe, Addis has numerous high rise buildings; this study goes towards
these high rise buildings. The speed of construction of high rise buildings in Addis Ababa is very fast, for
example in 2000 e.c about 123 high rise buildings(above g+6) have got the construction permit ion from the
Addis Ababa administration only excluding the permit ions from the 10 sub-city administrations. This data
from the Central Statistics Agency was done before 6 years and the construction period estimated for these
building is that maximum of 5 years, this data makes the conclusion that there are a lot of high-rise buildings
simple. The fast increase in number of high-rise buildings is also a reason for the study.
There are also considerations which help for further study on the energy consumption and energy waste of
high rise buildings of Addis Ababa such as the ratio of land use (in Addis about 57% of land use is built area)
as a result the climatic effect of the buildings will influence the city negatively.
In order to solve the above high rise buildings related issues, more studies on the buildings and work on the
architectural design of buildings, engineering techniques and engineering alternatives, thinking on the
sustainability of buildings will be help full.
1.3 Challenges of High-rise Buildings in Addis Ababa
From the data given by the Central Statistics Agency, more than 70% of the permitted high-rise buildings to
be constructed by the year of 2008 are commercial use including private offices and public buildings. The
amount of energy consumption of the buildings depends on their functions. The following energy related
challenges observed in the high-rise buildings of Addis Ababa.

1- The Huge Energy Consumption by the commercial buildings in Addis Ababa and their energy wastage,
this problem is the most dreadful, the buildings consume large amount of energy for
 Lighting including the energy use for office machines and appliances,
 Cooking (kitchens for cafeterias and restaurants, water heating and cooling)
 Ventilation (heating and cooling of a building, building fans…
 Circulation (vertical circulation)
But none of the buildings generate energy.
2- Weak Life Cycle Cost/ Turnover – most of the buildings in Addis Ababa are weak on their turn over
cost due to huge energy consumption and maintenance cost. The energy consumption and
maintenance costs large amount of financial cost which directly influences the general turnover cost
of the building. The lower in building life also cause for weak turnover cost of a building. Such kind of
challenges effect for both investors and government at a time.
3- Cause for Urban Heat Island effect – The urban heat island (UHI) refers to the generally warm urban
temperatures compared to those over surrounding, non-urban, areas. Urban heat island effect of
Addis Ababa becomes visible due to lack of proper surface treatment and site treatment of built up
areas. High-rise buildings mainly considered the primary causes for the effect due to their surface
treatment and verticality.
4- Economical Cost – Public and large scale construction projects in Ethiopia are parts of the
country’s development initiative. It shared considerable amount of the country’s scarce financial
resources. In Ethiopia, the construction industry is the highest recipient of government budget
in terms of government development program. Consequently, public and large scale construction
projects consume an average annual rate of nearly 60%, according to MoWUD, (2006), and
58.2% according to Wubishet, (2004), of the government’s capital budget. The cost for energy
consumption and energy wastage of the buildings directly influence the economic development of the
country.
5- Negative environmental impacts – the pollutions and gas emissions also the challenges of high-rise
buildings due to lack of proper consideration of energy efficiency in buildings.
1.4 Objectives of the Research
Objectives of this project are a wide range on the solutions of energy consumptions and energy wastage
reduction. But to set clearly the objectives can be stated as follows depending on the potential which the
thesis can solve the problems on the high rise buildings:-
A. Enhancing the Energy Consumption of High-Rise Buildings: - as the data from the CSA shows about
95% of all commercial and residential buildings of Addis Ababa use electric city for their energy
demands. This consumption has negative impact on the national energy need of the country because
buildings in Addis Ababa starts to compete with industries and manufacturing plants for energy and

rather than being self-efficient buildings and provide alternative sustainable energy source using their
part of structure.
B. Reduction of Energy Wastage: - now a day every part of a building becomes more important for
energy source. Especially the outer surfaces of a building are more important for energy production
but vice versa of this idea in Addis Ababa the outer surfaces of a building observed being a cause for
energy wastage by prioritize the aesthetic value of the surfaces. One of the objectives of this project is
to use these surfaces as energy sources and also treat them to reduce the probability of being a cause
for energy wastage.
C. Maximizing the Turnover Cost of buildings: - in the commercial sector money is the leading factor for
the expansion of commercial buildings and to improve their quality. It is obvious that clients need
faster cost turnover of their building, to realize this buildings expected to be more economical on their
expenditure specially on the cost of energy and maintenance, recent study in the USA shows only 20%
of the total building life cycle cost is invested in the initial construction of the building, about 67% cost
invested on the energy and maintenance of the building life cycle. As a result working on the energy
consumption will help for the client to save more money and being profitable from the building.
D. Environmental Comfort: - also this research aimed to own safe environment and comfortable climate
for the users of the building and for the whole surrounding community. Reducing the emission of CO2
and reducing the wastage of energy will help to improve the climate of the environment.
E. Care for the health of the Community: - this study also aims for protection of reflections from the
glazing of the building surfaces which is very harmful for the visual comfort of the users of the area.
1.5 The Research Motivations
To assess the objectives, beneficiaries, and methodology of the research work it is diagnosed using a
question and answer approach as shown below;
 Why has the research been established?
ANS. Most High-rise buildings in Addis Ababa suffer energy wastage challenge and over cost for energy.
 What does the research try to achieve?
ANS. To contribute knowledge on problems of energy wastage and their causes and provide conceptual
design principles and design guide lines.
 What are the important issues for the research?
ANS. Methodology and literature review together with professional interviews and desk study on
energy efficiency in buildings.
 Who will benefit from or affected by this research?
ANS. Stake holders in construction industry and myself.

 How can the research be done?
ANS. Literature review, interviews with professionals, desk study and analysis on energy efficiency and
energy wastage reduction of high-rise buildings.
The initiation for the study of this research is largely due to personal observation and low
performance of high-rise buildings of Addis Ababa in terms of energy efficiency and energy wastage
reduction. These include high-rise buildings owned by the government and the private sectors.
1.6 Over View of the Research Process/Methodology
This thesis will have the following broad categories.
Chapter One: Introduction/The research background
Chapter Two: Literature review
Chapter Three: The research design and methodology
Chapter Four: The research analysis and findings
Chapter Five: The research conclusions and recommendations
Each of the above chapters will contain the following contents as stipulated below.
Chapter One describes the research overview, its initiation and purposes. It also indicates the research
objectives, how the research process is conducted and the contents of the research.
Chapter Two covers the literature review part of the thesis; the literature review will include general
information about energy, causes for wastage of energy and their overall effects.
Chapter Three covers the research methodology. The methodological approach consists of the overall
research strategy; the research design, the analysis of the data and writing of the research paper.
Chapter Four contains the discussion and analysis part. It contains the findings on causes and effects of
energy wastage and consumption; the rate of energy consumption in buildings.
Chapter Five in this part, the research conclusions and recommendations are presented. This will serve
as an action guideline to stakeholders in the construction industry.

CHAPTER TWO - LITERATURE REVIEW
2.1 General
Energy is critical for economic development. Its importance stems from the fact that energy is a basic input in
all productive activities, including the household sector. Energy is a necessary input to meet basic survival
needs.
As the main goal of this thesis is addressing the issue related with energy conservation and energy wastage of
high-rise buildings in Ethiopia, it is important to understand the basic sources of energy in Ethiopia.
Ethiopia is a land locked country in the horn of Africa which endowed with natural resources like the
geothermal energy potential, wind energy, solar radiation energy potential, and with important land feature
for hydropower production and comfortable climate. For brief descriptions of the potentials of the country in
the energy sector there are literatures from the national energy policy. (The Ethiopian Economy, by Mengistu
Teferra)
Energy background in Ethiopia
Ethiopia's Energy consumption is predominantly based on biomass energy sources. An overwhelming
proportion (94%) of the country's energy demand is met by traditional energy sources such as fuel wood,
charcoal, branches, dung cakes and agricultural residues. The balance is met by commercial energy sources
such as electricity and petroleum. The most important issue in the energy sector is the supply of household
fuels, which is associated with massive deforestation and the resultant land degradation. The increasing
scarcity of fuel wood is compounded by Ethiopia's high population growth rate.
Though Ethiopia is endowed with vast energy resources 30,000 MW hydropower resources, 1387 million TOE
biomass resources, 17.5 million TOE agricultural residue, over 100 billion cubic meter of natural gas, 4000MW
geothermal energy, 40.3 million tons of coal and oil shale and vast resources of solar and wind energy, it has
not been able to develop, transform and utilize these resources for optimal economic development. (The
Ethiopian Economy, by Mengistu Teferra)

2.2 Energy potentials in Ethiopia
Hydro-energy
The gross hydro-energy potential of the whole Ethiopian territory is in the order of 650 Twh/year which is
estimated to be 8 per cent of Africa's potential. More than three-quarters of this potential is available from
mountain reservoirs with flow regulation. About one-fifth of the hydro-energy is available as river plain flow.
Between one-third and one-half of the total potential is due to the Blue Nile basin (280 Twh/year). The Blue
Nile and the Omo basins taken together contribute close to 400 Twh/year to the gross potential. If exploited
at 15 to 30 per cent of potential, the Blue Nile and the Omo basins could provide 70 to 120Twh/year or about
fifty times the present installed capacity in the hydro grid. (The Ethiopian Economy, by Mengistu Teferra)
Geothermal
Practically all of the geothermal potential in Ethiopia is contained in the Rift Valley extending along the thin
(60 km wide) main Ethiopian rift. Based on the geotectonic environment, the nature and extent of the
hydrothermal manifestations, the chemical composition of the fluids and geothermometric calculations, etc.
available resources suitable for power production have been estimated at about 700 MW. (The Ethiopian
Economy, by Mengistu Teferra)
Solar Energy
The yearly average daily radiation reaching the ground is 5.20kwh/m2. Throughout Ethiopia, the annual
distribution of mean global daily radiation is quite narrow, allowing the most efficient use of solar systems.
The total primary solar radiation reaching the ground may be estimated at about 1,953million Tcals/year.
(The Ethiopian Economy, by Mengistu Teferra)
Natural Gas
Significant natural gas resources have been discovered in the Ogaden region of eastern Ethiopia to the extent
of at least 30 to 60 billion m3, giving rise to considerable expectations of oil and gas potential, thereby
spurring exploration activity in the area. For the country as a whole, however, the available information is
insufficient to make even rough guesses of oil and gas resources and reserves. The level of exploration
activities has been very low compared to other areas of the world with similar prospective potential as
indicated by geological evidence. (The Ethiopian Economy, by Mengistu Teferra)

Biomass
Wood biomass resources in Ethiopia amount to about 13.8 million Tcals in terms of standing stock and 930
thousand Tcals in terms of annual yield. The figure for the annual consumption is several times lower. Three
regions, Kefa, Illubabor, and Bale, occupying less than one-fifth of the land area, account for over half of the
wood biomass resources. Almost three-quarters of the total resource base are contained on one-third of the
land surface. Nine regions, with about two-thirds of the land area, contribute a little over one quarter of the
total wood biomass resource.
A major feature of the fuel-wood problem is the strong mismatch between the location of forest resources
and the concentration of the population, largely occupying currently deforested land or areas which are being
rapidly deforested. Thus, most of the exploitable resource, located in areas with relatively low population
density, remains unutilized or is lost in the life cycle process, while over vast expanses of the country;
excessive exploitation by the bulk of Ethiopia's population is leading to critical levels of deforestation. (The
Ethiopian Economy, by Mengistu Teferra)
Coal
Coal resources appear to be quite widespread in Ethiopia, with occurrences in at least one-half of the
country's administrative regions. With the possible exception of a recent discovery at Dilbi in the south-west,
the hitherto known deposits are of lignite category with relatively low heating value, often as low as 1,000 to
2,000 Kcal/kg. Other basic problems with currently known Ethiopian coal resources are the high ash content
and occasionally high sulphur content. Moreover, the deposits exist in small patches. (The Ethiopian Economy, by
Mengistu Teferra)
Wind
The total wind resource may be estimated at 4.8million Tcals/yr. Only a small part of this potential may be
considered exploitable. Environmental constraints such as the disruption ‘of land systems in the case of heavy
concentration of wind machines limit the exploitable potential to around 240 Tcals/year or about 192
Mcals/km2 /year over broad areas of land. (Ministry of mine and energy)
2.3 Energy consumption rate in Ethiopia
The energy sector in Ethiopia can indeed be looked upon as an asset rather than a liability to development.
Several sectors can take advantage of the energy resources and, in fact, hinge their development on the
availability of a wide range of energy forms to meet their needs at low costs. There are constraints in the

development of the energy resources, but these constraints are expected to diminish with growth in the
other sectors. Economic growth in the other sectors will generate increased demand for energy. The
increased energy demand will mean economies of scale for energy projects and the resulting increases in
energy sales will mean greater capability for investment in the energy sector.
Energy Consumption Diagram in Billion kw-h

2.4 Benefits of Energy Efficiency
Takings steps to be more energy efficient is about using less energy to do the things we need. Improving
energy efficiency can deliver a range of benefits to the economy and society. Below is a list of benefits, using
the afore‐mentioned typology regarding the levels of benefits:
 Health and wellbeing impacts - This mainly relates to the public health improvements observed as a
result of improved heating and cooling of buildings and air quality from more efficient transport and
power generation and less demand for both.
 Poverty alleviation: Energy affordability and access - As energy demand and bills are reduced for the
poor, these households have the ability to acquire more and better energy services, as well as free up
income to spend on satisfying other critical needs. In addition, as utilities (notably in developing
countries) improve their supply‐side efficiency, they can provide more electricity to more households,
thereby supporting increased access initiatives which is often an important stated objective of supply‐
side energy efficiency activities in developing countries.
 Increased disposable income - Across all income levels, when energy efficiency improves, reduced
energy bills provide increased disposable income for households, individuals, and enterprises. The
effect of increased spending and investment can in turn result in positive macroeconomic effects
described below.
 Industrial productivity and competitiveness - Benefits for industrial firms from improvements in
energy efficiency improvements include reductions in resource use and pollution, improved
production and capacity utilization, and less operation and maintenance, which leads to improved
productivity and competitiveness.
 Energy provider and infrastructure benefits
Improved energy efficiency can help energy providers provide better energy services for their
customers, reducing operating costs and improving profit margins.
 Increased asset values
There is evidence that investors are willing to pay a rental and sales premium for property with better
energy performance. Some values of this premium have been estimated for commercial property.
 Job creation
Investment in energy efficiency and the increased disposable income can lead to direct and indirect
job creation in energy and other sectors. This makes energy efficiency an important part of
governments’ green growth strategy.
 Reduced energy‐related public expenditures
The public budgetary position can be improved through lower expenditures on energy in the public
sector (including by government agencies on energy consumption and state‐owned utilities on
fuel purchases). In countries where fuels are imported there is a related likely positive impact on
currency reserves, and in energy‐exporting countries domestic energy efficiency can free up more

fuels for export. In addition, for countries with energy consumption subsidies, reduced consumption
means lowered government budgetary outlays to finance these subsidies.
 Energy security - Improvements in energy efficiency leading to reduced demand for energy can
improve the security of energy systems across the four dimensions of risk: fuel availability
(geological), accessibility (geopolitical), affordability (economic) and acceptability (environmental and
social) (APERC, 2007; Kruyt et al., 2009). The IEA’s existing work on energy security underlines the
contribution that energy efficiency improvement can make to energy security. While policy makers
are alert to this connection, the multidimensional nature of energy security makes it difficult to
quantify and few studies have attempted this on a comprehensive, economy‐wide scale.
 Macroeconomic effects - Energy efficiency can have positive macroeconomic impacts, including
increases in GDP, and the cumulative benefits of the above‐mentioned impacts of improved trade
balance (for fuel‐importing countries), national competitiveness, and employment support.
These are mainly indirect effects resulting from increased consumer spending and economy‐wide
investment in energy efficiency, as well as from lower energy expenditures.
 Reduced GHG emissions - Greenhouse gas (GHG) emissions are reduced when energy efficiency
improvements result in reduced demand for fossil fuel energy. Many climate change mitigation
strategies put energy efficiency measures at their core as the most cost‐effective way to reduce
greenhouse gas emissions.
 Natural resource management -At an aggregated international level, less demand can reduce
pressure on resources, with potential beneficial impacts on prices (at least for importing
countries), as well as overall resource management. For example, in the context of peak oil and
related supply constraints, energy efficiency can help to relieve pressure on a scarce resource.
Similarly, expanding demand for oil etc., is pushing industry to increasingly challenging contexts for
extraction (such as deep off‐shore and shale oil extraction), with related incremental investment costs
and technological and environmental uncertainties.
 Moderating energy prices - If energy demand is reduced significantly across several markets, energy
prices can be reduced, particularly relative to the impact of the counter‐factual of increased energy
demand. This can have implications on economic competitiveness of countries, and, for individuals
across borders, improves the affordability of energy services and the availability of resources for
other expenditures. (Lisa Ryan and Nina Campbell)

2.5 The Effect of Urban Heat Island effect in Addis Ababa (case study)
HEAT ISLAND
One of the fundamental components that set a city apart from its rural surroundings is the climate that
prevails over urban environment. In urban areas, buildings and paved surfaces have gradually replaced
preexisting natural landscapes; As a result, solar energy is absorbed into roads and rooftops, causing the
surface temperature of urban structures to become up to 11°C higher than the ambient air temperature
(Taha, Akbari & Sallor 1992).
The image shows albedo values for various urban surfaces. The albedo is a measure of amount of solar
energy reflected by the surface. As such, low albedo implies higher surface temperature since the large
amounts of energy are absorbed. As surface throughout an entire community or city become hotter overall
ambient air temperature increase. This phenomenon is known as Urban Heat Island (UHI). Air temperature in
a city could rise by about 3°C or higher because of the effects of UHI. The resulting higher temperature
caused by the urban heat island had the effect of increasing the demand for cooling energy in commercial
and residential buildings in some large cities. (Bisrat Kifle, National Meteorological Services Agency)
Results and discussion
Both Minimum and Maximum temperature trends examined together with urban population increase during
the period between late 1960s and 2000. The total population increase in the eighteen years (1967-1984)
was 739,581 and the annual mean maximum temperature in the same period became warmer by 1.7ºC. The

annual mean maximum temperature attained its pick in the year 2000. It is interesting to observe that the
urban population was also highest in the same year.
A transect observation taken on 29 November 1999. The value of dry-bulb temperature measured at 0600
UTC in rural parts of the city (Bole Airport) is smaller than the values observed in urban areas of the city at
the central observatory by 3°C. Similar observations were made at 0900 UTC also show the same result.
However, at this time the gap between dry bulb temperatures between the two stations is 1°C.
At 1200 UTC air temperature was 22°C at Bole, while 23.4C° was recorded at the central station, which means
the urban center is warmer by about 1.4 °C. The UHI at 1500 UTC was 2.2°C. This confirms the existence of
UHI throughout the day although it attained its pick value during early morning. It is apparent from this study
that the UHI phenomena became the feature of the weather of Addis Ababa partly in association with the
increase in population. It is expected that as the city expands further the magnitude of the UHI would
become stronger affecting the living condition of the urban population. (Bisrat Kifle, National Meteorological Services
Agency)
2.6 Urban Expansion in Addis Ababa
Given Ethiopia’s history of being generally politically stable, it has become one of the main diplomatic centers
of Africa. As such, the national government is essentially uprooting entire neighborhoods in favor of hotels,
commercial buildings, and high-rises, completely transforming the city’s image to better fit the model of a
globally competitive city and to bring in more revenue. This process of rapid urban development is a cause for
the present built up ratio which is about 57% of the land of Addis. Below there is a map shows the
urbanization character of the city of Addis Ababa. (Various)

CHAPTER THREE – THE RESEARCH DESIGN AND METHODOLOGY
3.1 The Study Approach
Kumar, (1999), considers research as a process of collecting, analyzing and interpreting information to
provide solutions to questions. For the purpose of this thesis, research is defined as a practical
investigation or exploration to find out new facts or assemble old facts by scientific ways for the purpose
of developing existing theory or its application for real problems. Research can either be a theory based
(deductive), or a problem initiated for theory contribution (inductive), or a mixed approach to research.
3.2 The Research Type
The research is a practical problem developed from the observation of energy consumption in high-rise
building and the research questions are oriented to investigate the cause of energy wastage and their effects.
This research can be categorized as applied, exploratory, descriptive and co-relational type. It is applied and
exploratory because the research was initiated from practical problems and finds whether there exists energy
wastage or not. It is also descriptive and co-relational because it tried to describe the actual energy
consumption and wastage in graph and tries to provide design alternatives and conceptual design guide lines
for high-rise buildings in Addis Ababa.
3.3 The Study Scope and Limitation
Energy wastage in buildings is caused by many factors. Each causes of energy wastage have different rates of
occurrences and their impact on the building performance and lifecycle cost. Therefore, it is important to
identify both key causes of energy wastage based on their occurrence and their impact on building
performance and turnover cost.
The effects of energy wastage on the stakeholders, on the construction industry, and on the national
economy of the country will be identified. The research work was not without its problems and limitations
which were encountered throughout the preparation of this research. Its limitation is the unavailability of
adequate documented information in the field of the study, and the reluctance of some stakeholders in the
construction industry to provide information related to energy efficiency and performance of high-rise
buildings.
3.4 Data Source and Collection
The study has used the data sources to produce the following basic documents: respondents’
documents and archival documents. The respondents’ documents were collected using interviews with
clients (project owners), contractors and consultants. Archival documents were mostly from completed
projects (existed high-rise building) and written documents and research studied (in the form of books) from

concerned institutions for the study title. In addition, case studies and observations of the study area helped
to judge how problems on causes of energy wastage and how they are solved.
Data collection part of the research is the most tiresome part; the most difficult one is the respondents’
reluctance to react as per their promised schedule. The time schedule that was allocated to the research
and respondents reluctance not to respond quickly made the research stressful for the period of data
collection.
3.5 Research Methodology of Analysis
Both descriptive and inferential statistics are employed in the data analysis. In the analysis the “simple
subtraction” method is adopted to know the energy wastage amount in high-rise buildings.
Energy production – Energy consumption = energy wastage
“Computer software “used for changing the numbers given by the concerning institutions in to chart for
better comparison and analysis.
Computer graphics software (Revit Architecture) used for visualization of the energy wastage effects and
three dimensional look of the conceptual design recommendations.
3.6 Research Population
The research samples for interview are taken from stakeholders in the construction industry which are clients
(high-rise building owners), contractors and consultants, that are selected depending on their direct exposure
to building construction activities. Consultants were selected based on their class categories, such as
consultants above category 4 are selected. Consultants were selected depending on their experience of
construction.
3.7 Writing of the Research
The research contains four main parts. These are the research proposal, the literature review part, the
research methodology and analysis, and the final research writing. The research proposal writing was already
taken place. The literature review part took the longest period of the research. During this period, different
documents were collected and tested against the research objectives and the relevant information was
taken. Finally all the notes taken down were linked to produce a document; the differences in perceptions
between authors being noted down. The final research part was written after analyzing all primary and other
support documents to test the actual existing situation of high-rise buildings towards the research objectives.
Finally, the conclusions and recommendations part was written.

The final research writing was classified into the following five major parts for final documentation.
Chapter I: Introduction
Chapter II: Literature Review
Chapter III: The Research Design and Methodology
Chapter IV: Data Analysis and Discussion
Chapter V: Conclusions and Recommendations
Books from the Central Statistics Agency, (Addis Ababa, Ethiopia) & (Shire, Tigray, Ethiopia)
“THE FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA, CENTRAL STATISTICS AGENCY, ADDIS ABABA
The 2011/12 ETHIOPIAN HOUSEHOLD CONSUMPTION – EXPENDITURE (HCE) SURVEY”
STASTISTICAL ABSTRACT 20011”
WELFARE MONITORING SURVEY 2011
ANALYTICAL REPORT “

CHAPTER FOUR – ANALYSIS AND FINDINGS
4.1 Introduction
Energy Wastage and Energy Consumption of high-rise buildings are the basic issues to be addressed by this
study. These issues cause a series Urban Climatic Challenges, decrease the productivity and environmental
discomfort.
Addis Ababa as a capital city of the country and the center for big continental institutions like AU, having
embassies of different countries of the globe, Addis has numerous high rise buildings; this study goes towards
these high rise buildings. The speed of construction of high rise buildings in Addis Ababa is very fast, for
example in 2000 e.c about 123 high rise buildings(above g+6) have got the construction permit ion from the
Addis Ababa city administration only excluding the permit ions from the 10 sub-city administrations.
There are also considerations which help for further study on the energy consumption and energy waste of
high rise buildings of Addis Ababa such as the ratio of land use (in Addis about 57% of land use is built area)
as a result the climatic effect of the buildings will influence the city negatively.
As the speed of construction and number of high-rise buildings increase the focus should be on the quality
and energy sustainability of the buildings. Analyzing the Energy related issue of high-rise buildings will drive
the following importance for the city;
 Decreasing the Urban Island effect – energy wastage of high rise building is the main cause for the
warming up of the surrounding air. The energy from their surface, back reflection of sun radiation,
energy waste from their lighting system, and their material selection are some of the causes for
increasing the UHI effect (The UHI refers to the generally warm urban temperatures compared to
those over surrounding, non-urban, areas). Working on the architectural design aspects of high-rise
buildings (Geometry) significantly provides the solution for the issue which is one of the proposals of
this research.
 Create comfortable work environment and increase worker’s productivity – concerning with the
energy consumption of high-rise buildings is thinking about use of natural lighting and ventilation
system for buildings effectively. Most buildings consume a large amount of energy to replace the
natural ventilation and lighting in buildings. Use of natural light and ventilation helps for creating
comfortable work environment which increases the productivity of workers inside the building, And
saving the energy wasted for the manmade energy sources.
 Formulating building regulations and rules – in our context the rule related to energy consumption
and its effect not yet entertained in our building regulations. The study on the energy consumption
and energy wastage of high-rise building encompasses the geometry of a building, material selection,

and environmental and health impacts of a building. Such studies will help to formulate building
regulations related with Urban Canyon, Building Line and Building Skyline rules.
 Improving the Urban quality of the city – unlike rural areas, urban areas are dominated by the building blocks
and have less green areas. Improving the high-rise building’s surface treatment and introducing green
technology helps to increase the quality of the area. As proposal this study focuses on the surface treatment
and provides sample design for both surface treatment and for parking surface treatment.
 Increase the profitability of investors in high-rise buildings – for investors and clients of any project profit is
most of the time primary goal; in our context cost of a building is the main concern of clients. As a result
buildings expected to have long building life and less maintenance cost. This study makes buildings to be more
sustainable and energy efficient (using building geometry and passive solar energy techniques).
In order to achieve the above importance, this research document passes through different techniques of data
analyzing. Mostly the analyses done based on scientific researches and studies because the identified problem of the
research is not an optional or dependent on the willing of users, clients or government. The problem is all about
survival and quality of life which entirely influences for all of the community.
As the process of urbanization is a continuous process and the assumption on increasing of number of population is
strong, the concern to the environment and wellbeing of the society is not optional.
The study started with global climatic analysis of the city of Addis Ababa. And this is to clearly identify the contribution
of the universal influences on the local climatic character of the city. At the same time this global analysis helps to
separate the local urban challenges that this study can address them. At first stage identifying of the energy types and
their consumption of the city was challenging due to the lack of modernity in data collecting and store system. After the
analysis of the energy sources and consumption, knowing the possibilities and capacities of renewable energies was
important. The result of the analysis on the renewable energy potentials gives for how to harvest and integrate to the
building. Considering the existing buildings in Addis and studying what they have missed was the next and important
step of the study.
The deep analysis on both qualitative and quantitative on the local issues of the city gives the clue for relating the
challenges with Architectural design aspects of high-rise building. The study on the role of high-rise buildings in the
rising of the urban challenges was fundamental for formulating conceptual design proposals as solution for the
challenges.

4.2 Results
From the study it was easily observable that the urban challenges and discomfort of the city of Addis Ababa
comes due to less care for the building regulations and less value for the energy consumption and wastage of
the city. City wise Addis Ababa has fast urbanization speed comparing to the regional metropolitan cities. The
climatic condition of Addis Ababa becomes hotter than before. The rapid growth on the ratio of built up area
of the city create its own problem on the change of the climate of the city.
Generally the following data shows what the results and observations of the study mean;
Energy
consumption in
billion kw-h
1.27 1.51 1.52 1.59 1.59 2 1.91 2.13 2.94 2.94 3.13 3.13 3.36
Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
(Numerical data, National Energy Authority)
 Energy consumption ( in billion kw-h)
(Graphical interpretation of the energy consumption)
The energy consumption diagram shows an increase pattern from the year 2000Gc which was about 1.27
billion kw-h to the consumption of 3.36billion kw-h in the year of 2012Gc. The general trend of the diagram
tells that there is a need to use alternative energy conservation system. High-rise buildings and public
buildings share about 35% of the total energy consumption. This means architects should give priority for
energy consumption and reduction of energy wastage inside buildings.

Energy
production in
billion kw-h
1.36 1.63 1.63 1.71 1.71 2.15 2.06 2.29 3.27 3.27 3.46 3.46 3.72
Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
(Numerical data, National Energy Authority)
 Energy production (in billion kw-h)
(Graphical interpretation of the energy production)
Nowadays energy production becomes more important as energy is important factor for all kinds of
Development. The above diagram is made based on the last 13 years energy production. As the diagram
shows there is an increase tendency on the energy production. Within 13 years there is a change of almost
double in the energy production. The more energy production is also a cause for more energy wastage if
proper energy conservation and energy wastage reduction approach is not taken or implemented.
None of the high-rise buildings in Addis Ababa consider using its building part for energy conservation or
energy generation. The above Diagram shows the central energy production of the country. Buildings in Addis
are only energy consumers. The way they designed is Building Aesthetics and cost oriented. But it is
important to think energy sustainability in buildings for both energy conservation and cost effectiveness.

Energy wastage
in billion kw-h
0.09 0.12 0.11 0.12 0.12 0.15 0.15 0.16 0.33 0.33 0.33 0.33 0.36
Year 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
(Numerical data found by simple formula)
Energy production – Energy consumption = energy wastage
 Energy Wastage (in billion kw-h)
(Graphical interpretation of the energy wastage)
Energy wastage is one of the big concerns of the globe. Energy as it is the basic for all kinds of development.
But also it needs serious care to be not wasted easily. Energy wastage causes in different ways, starting from
unaware end users up to less consideration in professionals. Energy wastage in our context is more and
visible. the above diagram shows the energy wastage in billion kw-h which is wasted per year for the last
consecutive years(2000-2012 Gc).It is remarkably increasing the rate of energy wastage, by the year 2000 the
wastage was about 0.09 billion Kw-h or 90 million kw-h. This wastage dramatically increased to 0.36billion
kw-h or 360 million kw-h energy wastage. If this trend continues the impact on the economic development
will be more. Architects must consider the energy wastage in buildings and they must try to solve the
problem using architectural and engineering solutions.

 Number of Buildings diagram (in number per year)
Number of high-
rise buildings
permitted for
construction
33 51 72 98 139 178
Year 2004/1996 2005/1997 2006/1998 2007/1999 2008/2000 2009/2001
(Numerical data, Central Statistics Agency)
(Graphical interpretation of the number of high-rise buildings permitted to be constructed)
One of the basic reasons for the increase of energy consumptions is an increase in the number of high-rise
buildings. The above diagram is made based on the data from Addis Ababa municipality for the permitted
high-rise buildings (above G+5). In Addis Ababa starting from the year 1996 E.c up to 2001 E.c there is a
radical change on the number of high-rise buildings permitted to be constructed. The above diagram shows
that the number of buildings permitted to be constructed is increasing from 33 per year to 198 buildings per
year. The data shows the built-up area of the city becomes more and the energy demand for these spaces is
also more, it is architect’s responsibility to build buildings that are self-sustain and less energy consumers.

Sub city Yeka Gulele Arada Bole Kirkos Nefas
silk
lafto
Kolfe
keranyo
Lideta Addis
ketema
Akaki
kality
Number
of high-
rise
building
/2008
31 5 58 164 123 24 6 25 7 5
(Numerical data, Central Statistics Agency)
 Number of buildings in sub cities of Addis Ababa
(Graphical interpretation of the number of high-rise buildings in sub-cities)
The above diagram shows the condensed sub city with numbers of high-rise buildings in Addis Ababa, from
the data the Bole sub city is the more condensed sub city with high-rise buildings by the year of 2001 E.c. And
the Akaki kality and the Gulelle sub cities are the least condensed sub cities having only 5 buildings per year.
 Urban Heat Island effect in Addis Ababa
Many urban and suburban areas experience elevated temperatures compared to their outlying rural
surroundings; this difference in temperature is what constitutes an urban heat islands. As urban areas
develop, changes occur in the landscape. Buildings, roads, and other infrastructure replace open land
and vegetation. Surfaces that were once permeable and moist generally become impermeable and
dry. This development leads to the formation of urban heat islands—the phenomenon whereby urban
regions experience warmer temperatures than their rural surrounding. The effect of UHI in Addis is
becoming more visible as shown in the analysis.

Sketch of the Addis Ababa Urban Island Profile
Addis and its Urban Heat Island Level
A transect observation taken on 29 November 1999. The value of dry-bulb temperature measured at 0600
UTC in rural parts of the city (Bole Airport) is smaller than the values observed in urban areas of the city at
the central observatory by 3°C. Similar observations were made at 0900 UTC also show the same result.
However, at this time the gap between dry bulb temperatures between the two stations is 1°C.
At 12.00 UTC air temperature was 22°C at Bole, while 23.4C° was recorded at the central station, which
means the urban center is warmer by about 1.4 °C. The UHI at 1500 UTC was 2.2°C. This confirms the
existence of UHI throughout the day although it attained its pick value during early morning. It is apparent
from this study that the UHI phenomena became the feature of the weather of Addis Ababa partly in
association with the increase in population. It is expected that as the city expands further the magnitude of
the UHI would become stronger affecting the living condition of the urban population. (Bisrat Kifle, National
Meteorological Services Agency)
High-rise buildings of Addis Ababa Becomes more visible in contributing for the energy consumption and
energy wastage of the city. Those buildings shares about 35% (calculated from the above graph)of energy
consumption of the city. But none of the buildings contribute positively in the energy production or
conservation. The urbanization speed of the city is going faster this shows there will be more built-up areas
and large amount of energy will consumed by those buildings.
From the above results, the contribution of high-rise buildings for the urban problems is visible. Focusing on
the quality and energy sustainability of high-rise buildings is important for the city.
The observations from the study shows our architectural design and urban planning style and knowledge
should be energy oriented rather than concerning for number of rooms and rental profits of the owner. The

value given to the building aesthetics and form should be secondary. All the results lead to the strong
recommendation for the municipality to focus on the building regulations and rules and follow up their
implementation. In the case of Addis the energy consumption and wastage is increasing every year, the
Urban Heat Island effect also becomes more visible and character of the city. The result of these changes will
cause in less comfort ability of the city for inhabits.
From the previous results and indicators we can draw the following conclusions for every aspect of the
problem;
 Increase the Urban Heat Islands effect – increase in energy wastage and the urban canyon causes for
the increase of Urban Heat Island in Addis. The less consideration of multiple reflections from surfaces,
less surface heating consideration during the glazing of high-rise buildings and less consideration of
building’s geometry causes increase in the Urban Heat Island effect. As expressed in the introduction,
the weakness of the municipality that the building regulations related to building geometry, building
line, building skyline and Urban Canyon (urban canyons, which can be illustrated by a relatively narrow
street lined by tall buildings) not have been entertained as a result our designers don’t give value for
the geometry of the building and urban canyon unless they faced difficulty in construction technique
or technology. In order to reduce the Urban Heat Island effect in Addis, Building regulations related to
the above challenges should be drafted.
 Increase in Energy Wastage – there is a large amount of energy is wasted in high-rise buildings due to
excess use of mechanical energy for lighting and ventilating of buildings. The possible cause may be
less consciousness of designers how to maximize natural ventilation and use of direct sun light. And
also may be from the dependency of designers on the mechanical techniques for design solutions. By
increasing the use of natural ventilation and direct gain of sun light, proper surface treatment like
pavements, parking lots and roofs, we can dramatically decrease the energy wasted by the buildings.
 Increase in Energy Consumption – high-rise buildings of Addis Ababa own a large amount of vertical
surface but none of them harvest solar energy or use its part in energy conservation. Inversely they
cause for surface heating and increasing of surrounding air temperature. Our buildings should try to
harvest solar energy and convert it to their energy demand. And our buildings orientation also needs
care for proper use of wind direction in reducing the Urban Heat Island effect in the city.
4.3 Discussion
At the beginning of this study there were different points of view from different professionals related to the
final output and implication of the study. There were some impressions for the emergence of this study. The
first impression was the report from the Central Statistics Agency which shows the consumption rate of
energy in the country and it was shocking to hear, the second impression was the amount of energy wasted
during the installation and distributing for commercial and high-rise building, the third impression was the
international certified green buildings and their energy efficiency. Those impressions made the focus of the

study to be on the energy efficiency and energy wastage reduction of high-rise building. But in the process
the facts and quantitate data of the energy sector made the study stronger on the energy conservation and
reduction of energy wastage.
In the process of the study there were some different points of views entertained as discussion in the process
of the study.
 Working on the energy conservation and reduction of energy wastage using the architectural design
may affect the freedom of the architects for building geometry and design imaginary. The focus
should be on the mass production of energy stations (hydro power plants, wind turbines, geothermal
energy plants.. etc.) but such kind of ideas did not consider the following points:
 Environmental impacts
 Building turnover cost
 Structural capability
 Reality situations and capacities
 Architecture dominated by rules and politics
From the discussion this study entertained, the above idea was the strongest defending idea which
deals with the political aspect of the urban settlement. It stated as ‘such studies will come up with
building regulations and rules which totally very influential in the creativity and of the architect. And
the architecture of the city also will influenced by the political aspects of the government.’
Of course such studies are bases for building rules and regulations but also provide design solutions
options as well. Such studies more focus on the public and environmental health and wellbeing. The
defending idea was failed due to the following miss considerations;
 Lack of environmental consideration
 Misunderstanding the significance of the building regulations
 Wrong political perception on architecture
 Less value for climatic change
 Less consideration for reality capacity and construction conditions.
Generally the above discussions were important inputs to make the study more valuable and reasonable. The
study negotiations the above ideas and provides reliable evidences that strengthen the title and the need for
it. Working on the energy conservation and energy wastage reduction in high-rise buildings will improve the
quality of the building and urban environment. Such kinds of studies mainly consider the creation of healthy
and comfortable environment for inhabits. This point of view is acceptable by any inhabits in any continent
and in any situation even it differ in its implementation.

CHAPTER FIVE – CONCLUSION AND RECOMMENDATION
5.1 Principles of Energy Conservation in High-rise Buildings
There are three basic principles in the methodology for carrying out energy conservation measures for high-
rise buildings. The first principle is to fully match the high-rise building planning to the land and natural
features of the region in which the building is constructed. The second is to develop all technologies currently
available' for creating artificial environments in the direction of the most efficient utilization of energy. The
third principle for energy conservation is to reduce wastage by reducing excess run times and excess capacity.
To elaborate, the first principle calls in a sense for the adoption of building plans and technologies which
permit maximum utilization of the natural and environmental conditions fully matched to the land and
natural features of building site. For example, the building plan should not indiscreetly pursue any prevailing
style and design. This is because any country or city has its own natural environments (or characteristic
weather), natural features and topography, and the conditions for the construction of buildings will differ
widely with each region. Therefore, the optimum methods to be adopted for energy conservation should
certainly exist among local traditional technologies, which are rooted in local living styles. By far the most
distinct characteristic of these technologies is that they are almost always naturally oriented toward the
maximum utilization of environmental conditions created by natural energy.
As for the second principle, two approaches are conceivable - the method of using electrical and mechanical
systems in a manner permitting the most efficient utilization of energy and adopting planning and
construction technologies enabling maximum reduction of energy-consuming loads, or maximum
suppression of energy consumption. Regarding energy conservation through the adoption of optimum
building methods, this method essentially consists of inhibiting factors which have the effect of increasing
energy-consuming loads when operating the building's installed facilities and of conversely preventing the
outflow or loss of interior air-conditioning energy wherever possible.
The third principle primarily concerns the method of managing the building and aims to achieve energy
conservation through some extent by controlling run times and excessive capacities. This may be
accomplished by designing the building from the outset for flexible changing of interior design conditioning
with an existing building. This may be achieved by lowering the interior conditions to a certain level at
certain parts of the building for fixed periods of time. Specifically, this primarily involves the period where
the air-conditioning system is operating, the number of lifts in operation, or the period of time of illumination
on the window side of the building. (K.S. Kannan Member ASHRAE)
This study mainly focus on the first and third principles of energy conservation, the recommendations are
related with the architectural and design approaches of the issue.

5.2 Conceptual Design Recommendations
Architects can achieve energy efficiency in the buildings they design by studying the macro-and micro-climate
of the site, applying bioclimatic architectural principles to combat the adverse conditions, and taking
advantage of the desirable conditions. Some common design elements that directly or indirectly affect
thermal comfort conditions and thereby the energy consumption in a building is
(1) Building Orientation, (2) Landscaping, (3) Core plan (4) Building form
(5) Building envelope and fenestration (6) opening/window (7) External walls
1, Building Orientation
Building orientation is a significant design consideration, mainly with regard to solar radiation and wind. In
predominantly cold regions, buildings should be oriented to maximize solar gain; the reverse is advisable for
hot regions. In regions where seasonal changes are very pronounced, both the situations may arise
periodically. As the orientation exposes the building to more morning than afternoon sun and enables the
building to begin to heat during the day.
As compared with three- or four-story buildings, high-rise buildings which project into the skyline are exposed
more directly to the full impacts of external temperatures and radiant heat. The orientation has a great
relation with the energy conservation when determining the arrangement of a high-rise building. In general,
arranging the building with its main opening facing north to south provides the greatest advantage with
respect to the building's interior air-conditioning load.
In comparing air-conditioning loads with respect to various building orientations, it is observed from different
studies that a building arranged longitudinally from north to south has to bear an air-conditioning load that is
about 10% more than that of a building arranged longitudinally from east to west, regardless of the building's
architectural mode.
Addis Ababa has moderate climate with average sunlight of 9.7 hours per day and average day length of 11.8
hours. High-rise buildings of Addis Ababa should be properly oriented for maximization of solar energy gain.
Natural ventilation system should be the primarily care of high-rise buildings. Arranging the buildings
longitudinally east to west axis helps to reduce the air-conditioning load of the building and minimize the
energy wastage of the surfaces.

2, Landscaping
Landscaping is an important element in altering the microclimate of a place. Proper landscaping reduces
direct sun from striking and heating up of building surfaces. It prevents reflected light carrying heat into a
building from the ground (create Urban Heat Island effect) or other surfaces. Landscaping creates different
airflow patterns and can be used to direct or divert the wind advantageously by causing a pressure
difference. Additionally, the shade created by trees and the effect of grass and Shrubs reduce air
temperatures adjoining the building and provide evaporative cooling. Specially landscaping the southwest
side of the building is helpful in reducing the reflections from the facades of the tower.

Trees are the primary elements of an energy-conserving landscape. Landscaping include surface treatments
like the pavements and parking area cover. Some design recommendations are listed below;
A, parking surface design
All the data related with the number of vehicles in Addis Ababa shows increasing. For example in Addis there
are 450,000 vehicles according the estimation of the Central Statistics Agency in the end of 2013 GC. This
means the need for parking space is also dramatically increasing. As high-rise buildings are public buildings
they have a lot of workers inside, providing parking spaces for the workers and users will increase the
functionality of the building and volubility. But at the same time the quality of parking also has the power to
affect the users and building performance.
For Addis integrating greenery concept with the parking system is very important and highly recommended
because of the amount of land used for parking and the way it paved.
As shown in the picture, such kinds of green integrated parking spaces are recommended. The research study
shows parking surfaces are one of the factors in contributing for surface heating which causes for the Urban
Heat Island effect. Generally such kinds of parking design recommendations are important for the reason:
 Decreasing surface heating - Decreasing the amount of surfaces covered with asphalt or concrete.
Swapping the pavements with grassland directly decreasing the surface heating and lowering the
contribution for the Urban Heat Island effect.

 Improve parking use system – as shown in the picture the green lands used as standards of parking
marks. And simply guide the driver to a proper parking space. Such kind of design proposals offers
efficiency in the use of parking spaces.
 Environmental benefit – such parking has positive contribution for the environment. Generally they
are eco-friendly designs. Also they are positive contributors in cooling the car’s engine.
B, Open ground spaces and Pavement design
Making the ground floor of high-rise buildings open and making the floor of the ground sustainable (covering
with green integrated flooring) is highly recommended for the buildings of Addis Ababa. The main benefits of
the recommendations are:
 Improve interior space quality – as the air of a room follows the ‘stack effect’ the upper floors have
warmer air than the ground floor by the concept of denser air moves down and warmer air goes
up(less denser). Increasing the amount of cold (denser) air in the ground using greenery and open
spaces will bring a balance between the warmer and cooler air. The openness of the ground increasing
the speed of air exchange.
 Importance for decreasing UHI effect – open ground floor increase the speed of air exchange and
create the chance for exchanging of the warmer air of the urban area with the cooler air of the
surrounding areas(open and countryside). This exchange of air decreases the rise in temperature of an
urban settlement.
 Improve public activity – open ground spaces are preferable by the peoples living in a city. And such
open spaces with entertainment and street side activities attract peoples and user to the space and
make the place more active. The main importance of the making open ground and attractive is that it
rises the land use value of the area and the building as well. Increasing the land use value and rental

value of the upper floors of the building generate income and improve the turnover cost of the
building.
 Environmental benefit – such design approaches are more significant in making the building zero
energy building and reducing the energy wastage of the building. Open ground floors
recommendation for high-rise buildings is preferable to make the upper floor rooms more
comfortable and prized.
3, Core Plan of a building
Giving due thought to the core is a vital matter when designing the typical floor plan of a high-rise building.
This is because the core plan's specific position in the building determines what parts of the peripheral walls
will become the openings and what parts will comprise the building's external walls.
The core of the building has to be designed by giving due thought to various factors such as the method of
using the building's plans, the disaster prevention system, and the structural plan. Here, the core mode is
classified into three types - center core, double core, and single-sided core.
The core type providing the minimum air-conditioning load is the double core, in which the opening runs
from north to south and the core runs from east to west. Conversely, the core type characterized by
maximum air-conditioning load is the center core in which the main lighting opening lies in the southeast and
northwest directions.
A survey of the core types of existing high-rise buildings in Addis Ababa shows that there are few double-
core-type buildings. The center-core design is adopted primarily for rental buildings and the double-core
design is primarily for own-use buildings (e.g., government or private corporate uses) since wide spaces can
be obtained flexibly.

This difference stems from the fact that with the center-core-type building the office spaces are rented out to
tenants without providing a special corridor, whereas the double-core type building requires the provision of
a special corridor that results in poorer rental efficiency. However, it goes without saying that the plan of
high-rise buildings, inclusive of its core plan, should be designed not merely from this economic consideration
but from the aspect of energy conservation as well.
4, Building form /Geometry
The volume of space inside a building that needs to be heated or cooled and its relationship with the area of
the envelope enclosing the volume affects the thermal performance of the building. This parameter, known
as the S/V
(surface-to-volume) ratio is determined by the building form. For any given building volume, the more
compacts the shape, the less wasteful it is in gaining/losing heat. Hence, in hot, dry, regions and cold
climates, buildings are compact in form with a low S/V ratio to reduce heat gain and losses respectively. Also,
the building form determines the airflow pattern around the building, directly affecting its ventilation. The
depth of a building also determines the requirements for artificial lighting - greater more the depth, higher
the need for artificial lighting. Some Building geometry findings shows the following result;
a. For high-rise, the vertical wall is most critical, 86.6% of the annual total insolation is received from its
vertical wall surfaces.
b. Circular shape with W/L ratio 1:1 is the optimum geometric shape (receiving the lowest amounts of annual
total solar insolation) among all high-rise building shapes.

c. The highest level of daily average solar insolation is received on the east wall, followed by the south, west
and north walls.
With appropriate attentions given to the geometric shapes and solar shading strategies, the impact of solar
radiation on high-rise building envelopes can be reduced. Hence, it can be assumed that the energy
consumption for cooling/heating load in such high-rise building will be minimized.
Based on the above facts the following design categories for the geometry of high rise buildings of Addis
Ababa are proposed;
A, Vertical Building geometry proposal
In this category the aim of this proposal is to increase the use of natural light and ventilation system, to
reduce the reflections reaching the ground, and to create a building geometry comfortable for green
integration. This building geometry proposal will reduce the Urban Heat Island effect of the city by reducing
the reflections and surface volume of the building. As the geometry implies decreasing in surface –volume
ratio of buildings when they raise stories up, all the above goals can easily achieved.
The above building geometry is recommended based on the following facts on geometry:
A- Decreasing the surface volume of a building – as shown in the diagram the surface volume of the
building decreasing when it goes up floors. This mainly helps to increasing the probability of the
rooms to get direct sunlight and fresh air. If the probability of rooms to get natural ventilation and
fresh air is increased just the building is capable of decreasing energy wastage and consumption. Also

the building geometry helps to reduce multiple reflections of glazed facades of buildings which is the
most important for decreasing the Urban Heat Island effect.
B- Improve productivity – such kind of geometry increase the direct connection through visual
connection with environment and greenery areas which definitely increase the productivity of the
workers inside the building. Visual connections with outside makes the workers to stay more time in
their office and improve their work motivation psychologically.
C- Greenery Integration – the geometry of a building helps to integrate easily greenery parts with less
cost of construction and treatment. Also such kind of building geometries preferable for use of passive
energy systems (photovoltaic solar panels); this helps to easily produce alternative energy source.
D- Construction cost – the above kind of building geometries have less construction cost comparing with
the other geometries due to their construction technique. In other hand being easy in construction
helps to reduce the construction period and increase the turn over cost of the building.
E- Maintenance cost and structural stability – geometry of a building has great impact on the stability
and structural feasibility of a building. Such kind of building geometry helps to create stable and safe
building because such building geometries are capable of resisting natural disaster.
B, Urban Canyon geometry
Urban canyon geometry proposal is mainly deals with spaces in between towers of high-rise buildings. The
spatial relationship of towers of high-rise buildings should be considered in the perspectives of wind blocking,
the smock stack effect of the urban area, and the multiple reflection of sun radiation and surface heating of
the surrounding.
This proposal states that there will not be connection between towers of high-rise buildings. The space
between the towers is very fundamental for wind transfer and enables the urban hot air to be exchanged
with surrounding rural area which has cooler air temperature. The second deal is with the ground space of
high-rise buildings it is advisable to be more open for air transfer and building quality by introducing functions
dominated by outdoor activities. This will help the hot air of the surface easily goes up and side to exchange
with the cooler and denser air in the upper atmosphere.

C, Building ventilation design / system
The most effective form of natural ventilation is cross ventilation, where air is able to pass from one side of a
building to the other. For this to work effectively it typically dictates that buildings are no morethan12-15m in
depth. However, in deeper plan spaces, natural ventilation can be achieved by introducing central Atria and
making use of the “stack effect” to draw air from the outer perimeter and up through the center of the
building. The energy requirements for ventilation can be reduced with proper building design to use the cross
ventilation and stack effect ventilation systems.

5, Building Envelope
A building envelope is the physical separators between the conditioned and unconditioned environment of a
building including the resistance to air, water, heat, light, and noise transfer. The three basic elements of a
building envelope are a weather barrier, air barrier, and thermal barrier.
The building envelope is all of the elements of the outer shell that maintain a dry, heated or cooled indoor
environment and facilitate its climate control. Building envelope design is a specialized area of architectural
and engineering practice that draws from all areas of building science and indoor climate control.
The many functions of the building envelope can be separated into three categories:
 Support (to resist and transfer mechanical loads)
 Control (the flow of matter and energy of all types)
 Finish (to meet human desires on the inside and outside)
In the case of Addis Ababa most of the building envelopes are mainly serve as finish (to meet human desires
and aesthetical values). Making the building envelope design based on the indoor and outdoor climatic
analysis helps to be the building energy efficient and zero energy building.
6, Opening/Windows
The location of openings for ventilation is determined by prevalent wind direction. Openings at higher levels
naturally aid in venting out hot air. Size, shape and orientation of openings moderate air velocity and flow in
the room; a small inlet and large outlet increase velocity and distribution of airflow through the room. When
possible, the building should be so positioned on the site that takes it advantage of prevailing winds.
Windows have a major effect on energy consumption of the building due to solar heat gain, heat
transmission, and infiltration. The percentage glass area, type of glass, single or double glazing, and the
presence of sun-shading devices determine the heat gain through windows.
For the high-rise buildings of Addis Ababa large glazed openings are preferable in order to use the sun
radiation for heating the interior climate of the building. Addis Ababa has moderate climate which is helpful
for maximization of solar gain but a special care must be taken to consideration in the orientation and kind of
opening. Introducing louvers and recessed windows are helpful in defusing the light which inters to the
building.

7, External Walls
The roofs and external walls of high-rise buildings play a vital role in the prevention of inflow of external heat.
However, heat insulation for limiting thermal infiltration through roofs and walls has the adverse effect of
obstructing the outflow of heat accumulated during the daytime into the exterior environment when the
external temperature falls below that of the interior-rooms (at night), with the result that the residual heat
acts as an additional air-conditioning load the following day. Thermal insulation is used not only to prevent
inflow of heat and interior cooling loads, but also to create room environments that are hardly influenced
fluctuations in external temperature. As for accomplishing thermal insulation, the method of treating the
exterior facing of the building provides a much greater effect than giving heat insulation treatment to the
building's interior facings. The greatest effect is provided by giving heat insulation treatment to the roof. The
surface color of the exterior walls is an important factor in reducing solar heat gain through opaque wall
sections. Light colors reflect solar radiation more than dark colors.
The external finish of a surface determines the amount of heat absorbed or reflected by it. For example, a
smooth and light color surface reflects more light and heat in comparison to a dark color surface. Lighter
color surfaces have higher emissivity and should be ideally used for warm climate.
High-rise buildings share large amount of exterior surface which exposed to sun radiation. The coloring and
finish treatment should be analyzed in the perspective of energy conservation and thermal comfort of the
building. In Addis Ababa more focus is given to the color composition and aesthetically harmony of the colors
but the coloring and finishing of exterior wall should be based on the climatic analysis of the area.

5.3 Municipality Related Recommendations
The general result of the study implies that the focus should be towards the building’s regulations and rules
in order to control the quality and energy efficiency of high-rise buildings. Buildings often have the power to
improve or downhill the well-being of a community. Designing a building is like treating a community both
psychologically and physically. There are some recommendations for better result in the study area;
 Building regulations and rules about energy consumption, energy wastage should be drafted. The
present building code directive of the federal democratic republic of Ethiopia “Council of Ministers
Building Regulation No. 243/2011” states that for approval of a design plan for high-rise buildings
needs structural and electro mechanical analysis in addition of the architectural, electrical and
sanitary plans, but it doesn’t ask analysis about energy and environmental issues. This study strongly
recommends being mandatory for energy analysis for the approval of high-rise buildings.
 According “Council of Ministers Building Regulation No. 243/2011” Building setbacks and building
skyline rules are stated related with the privacy and security, but they have to consider primarily the
concept of urban canyon.
 Building material properties, surface finishes and reflection patterns should be considered in the
regulations. Material and finishing analysis should be asked during plan approval, the “Council of
Ministers Building Regulation No. 243/2011” should made the analysis of materials and finishing
obligatory on the building code regulations.
 The existence of greenery area should be obligatory, improving the percentage of built-up ratio, the
building regulations and directives must give due to the percentage of greenery and its position.
 Special awards should be organized annually for green and energy efficient buildings of the city.

5.4 Conclusion
Energy aspect of a building is the basic need to be the building functional. All the facilities and functional units
of a building work out with the help of energy. As a result enabling the building to be energy efficient is
making Architecture alive. Buildings shouldn’t be only a shelter or work space which needs energy to be
functional but buildings should try to cover their energy demand /consumption or at least not to be a cause
for environmental challenge.
In urban settlement buildings cover large amount of land use, if buildings designed being energy efficient
they have the power to stabilize the city in both climatically and energy wisely. Increasing the workers’
productivity is also the fruit of well-designed and energy sustained buildings.
Making buildings energy efficient and zero energy wastage is the question of current architecture. In urban
areas buildings share the highest percentage of the land; proper design of high-rise buildings starting from
their orientation up to the material selection has great influence on their energy consumption. As capital city,
Addis Ababa faces the urban challenges like increase in temperature, uncomfortable working spaces inside
high-rise buildings, and environmental impacts and pollutions. All the design proposals will be effective if they
are integrated with buildings and recreational centers in the city. Building regulations are needed to be
drafted for effective implementation of the design proposals. Finally it is the architect’s duty to design energy
efficient and urban challenges responding building.

References
 Energy and Economic Growth in Ethiopia, by Mengistu Teferra
 Energy Policy of Ethiopia, by Melis Teka,
Ministry of Mines and Energy
 URBAN HEAT ISLAND and ITS FEATURE IN ADDIS ABABA, by Bisrat Kifle
National Meteorological Services Agency, Addis Ababa, Ethiopia
 Building Envelope Design Consideration For Energy Conserving High-rise Buildings
By K.S. Kannan, member ASHRAE
 Uses of Landscaping for Energy Conservation
Gianni, Florida; Department of physical sciences, Florida International University
 Socio-Economic profile of Addis Ababa for the year 2011/12
Policy Study and Analysis Sub-process
 Energy Efficiency in Architecture: an overview
 IUAC Teaching Resources
The Urban Canopy Layer Heat Island
 Books from the Central Statistics Agency, (Addis Ababa, Ethiopia) & (Shire, Tigray, Ethiopia)
The 2011/12 ETHIOPIAN HOUSEHOLD CONSUMPTION – EXPENDITURE (HCE) SURVEY”
STASTISTICAL ABSTRACT 20011”
WELFARE MONITORING SURVEY 2011, ANALYTICAL REPORT “

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