Noyan Ulusarac Final Year Project

Noyan Ulusarac 1134280
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Critical Assessment of Sustainable Buildings in Terms of Energy
Consumptions and 𝐂𝐎 𝟐
Emissions
Noyan Ulusarac
1134280
Individual Dissertation submitted to the Department of Civil Engineering
School of Engineering and Design, Brunel University

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ABSTRACT
Over the decades, world’s population is reached to its limit. Nowadays, environmental sources are not
enough for the requirements of the human kind. Eco-system is changing day by day, earth is getting old.
Therefore, precautions have to be taken. For civil engineering, buildings have to be built according to
the regulations which require specific details in order to lower the damage of the structures on the
environment. This project is about the critical assessment of the sustainable (eco-friendly) buildings in
terms of energy consumptions and CO2 emissions in order to show that they are necessary for the
future.

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ACKNOWLEDGEMENTS
This research was supported by Brunel University, Alarko Holding, Koray Holding, Varlıbas Holding
(VARYAP), GAP Holding, Mehmet Ulusarac, Mustafa Ulusarac, Ahmet Serpil, Yüce Demirseren,
Nusrettin Isık, Laila Mouakko, Sana El Hachadı, Adem Koray Parlar, Gökhan Girgin, Mohamed
Elazzouzi, Youssef El Haoudar and Azzeddin Harache. The author is grateful to the companies and
people involved for their support and contribution.

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TABLE OF CONTENTS
Page Number
List of Notation............................................................................................................................. 5
Definitions ................................................................................................................................ 5
Terms....................................................................................................................................... 5
Introduction.................................................................................................................................. 6
Traditional (non-sustainable) Buildings....................................................................................... 8
Retrofit of Traditional Buildings in Terms of Energy Consumption .............................................. 9
Literature Review.........................................................................................................................17
What is Sustainable Building?...................................................................................................17
Benefits of Sustainable Buildings ..............................................................................................18
Limitations of Sustainable Buildings .........................................................................................19
Cost in Sustainable Buildings....................................................................................................20
Relationship Between Sustainable Buildings and CO2 Emission.................................................20
Relationship Between Energy Consumptions of Sustainable Buildings and CO2 Emission ............22
Information About Sustainable Building Regulations..................................................................28
Sustainability in Today’s World ................................................................................................31
Research Methodology.................................................................................................................32
Results and Discussion .................................................................................................................35
Awareness on Key Sustainability Issues in Buildings..................................................................35
Energy Consumptions and CO2 Emissions of Both Sustainable Buildings and Traditional Buildings
...............................................................................................................................................36
CO2 Emissions of The Traditional (Non-sustainable) Buildings...................................................37
CO2 Emissions of The Sustainable Buildings .............................................................................38
Energy Consumption of The Traditional (Non-sustainable) Buildings..........................................39
Energy Consumption of The Sustainable Buildings ....................................................................41
Energy Consumption of The Sustainable Buildings versus Traditional Buildings..........................42
Energy Efficiency Materials at The Sustainable Buildings...........................................................42
Future of The Sustainable Buildings ..........................................................................................43
Conclusions .................................................................................................................................44
References...................................................................................................................................46
Appendices..................................................................................................................................49

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LIST OF NOTATION
Definitions
BTUs - British thermal units - a traditional unit of energy equal to about 1055 joules.
GWh – Giga Watts hours - a unit of energy representing one billion (1,000,000,000) watt hours and is
equivalent to one million kilowatt hours.
KWh – Kilowatt hours.
CO2 – Carbon dioxide gas – chemical formula of the combination of 1 carbon atom and 2 oxygen
atoms.
Grey water – waste water from showers, baths and washbasins.
Greenhouse gases (GHGs) - a gas in an atmosphere that absorbs and emits radiation within the thermal
infrared range.
GDP – Gross domestic product.
USD – United States Dollar.
Gt – Giga tonnes - 1 billion tonnes or 1 trillion kilograms.
PV – Photovoltaic.
ST – Solar thermal.
Therm - One British therm is a non-SI unit of heat energy equal to 100,000 British thermal units (BTU).
RES – Renewable energy sources.
Terms
IRENA – International Renewable Energy Agency
HVAC – Heating, ventilation and air conditioning
USGBC - United States Green Building Council
USEPA – United States Environmental Protection Agency
LEED - Leadership in Energy and Environmental Design
BREEAM - Building Research Establishment Environmental Assessment Methodology
ASME - American Society of Mechanical Engineers
UNEP SBCI - United Nations Environment Programme Sustainable Buildings and Climate Initiative
IPCC - Intergovernmental Panel on Climate Change
USGBC - U.S Green Building Council
OECD Pacific - Organisation for Economic Co-operation and Development

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INTRODUCTION
In today’s world, technology is far more essential in many aspects than predicted in 1960’s or 1970’s.
Thanks to those technologies, we are living our life more efficient, easy and joyful. Almost every
technological device uses energy (electricity) which is gained from world’s electricity and that
electricity is being produced by electric centrals. According to the Central Intelligence Agency of
the United States (2009); in 2008 there were 6,785 million people living and their electric consumption
was 20,279,640 Gwh/yr which costs $70,048 billion (USD). Therefore, world’s average productivity
per electricity consumption was $3.5 production/kWh. To sum up, energy consumption was high and as
a result of that people needed more energy and started building more electric centrals, hydroelectric
centrals etc. However, these electric centrals are producing carbon dioxide gases when they are
producing electricity and these carbon dioxides gases are harming the nature and the health conditions
of the environment. As a result of these effects, global warming (increases in average temperature of
the air and sea at earth's surface) occurs. According to the Figure 1 which is shown below and also
according to Thomas F.S et al. (2013), since 1971, 90% of the warming has occurred in the oceans. Ices
started melting at the poles therefore level of the sea started increasing. According to the National
Academies Press (2011) “The average temperature of the Earth’s surface increased by about 0.8 °C
(1.4 °F) over the past 100 years, with about 0.6 °C (1.0 °F) of this warming occurring over just the past
three decades.” AllCO2consumptions were affecting the atmosphere and therefore our life. According
to the Pachauri R.K et al. (2007), scientists were certain that most of the global warming was being
caused due to the increase at the level of the concentrations of the greenhouse gases which are produced
by human activities. Main reasons were energy consumptions and CO2 emission.
Figure 1 – Temperature, CO2 and Sunspots change, Stanford Solar Centre website
(http://solar-center.stanford.edu/sun-on-earth/glob-warm.html)
For example industries, they have a major effect on the global warming. According to Pijush K. B.
(2010) “Most of the times residue of industries which are generally composed of different poisonous
materials in gaseous form causing global warming, are either thrown out or burnt in open air after being
exhausted through openings of a long heighten chimney. In manufacturing industry, oil-refineries,
petrochemical, chemical industries and heavy industries etc, the last residue is consisting of some sort
of oil, acid, bases, hydrocarbon cycles etc which are highly poisonous and furiously affected in contact
of human and biological living bodies” According to R. Chandrappa et al. (2011) “With industrial
revolution, a series of environmental impacts appeared – air pollution, water pollution, thermal
pollution, noise pollution and degradation of forest and other ecosystems. Increase in carbon dioxide led
to global warming due to green house effect. Industrialized countries have accumulated ‘historical’

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emissions, in the atmosphere since the beginning of the industrial revolution. Very recently, developing
countries are only adding to this carbon pool already created in the atmosphere.” Moreover; each year
the UK construction industry uses 6 tonnes of building materials per head of pollution and 151 million
tonnes of waste; 35% of UK total waste, comes from materials production and construction (Mizi
F.,2011). According to Levine et al. (2007) “Carbon dioxide emissions, including through the use of
electricity in buildings, grew from 1971 to 2004 at an annual rate of 2%. The largest regional increases
in CO2 emissions (including through the use of electricity) for commercial buildings were from
developing Asia (30%), North America (29%) and OECD Pacific (18%). The largest regional increase
in CO2 emissions for residential buildings was from Developing Asia accounting for 42% and Middle
East/North Africa with 19%.” According to Michael Dore (2011) “Humans are producing 29 gigatons
of CO2 in a year and atmospheric CO2 is at its highest level in 15 to 20 million years. Atmospheric
concentration of CO2 has increased by 35% since the beginning of the age of industrialization.”
Figure 2 - Carbon dioxide emissions from energy, (IPCC, 2004)
As shown in the Figure 2, according to the website of IPCC “The bar at the left represents emissions of
CO2 from all energy end-uses in buildings. The bar at the right represents only those emissions from
direct combustion of fossil fuels.” In both cases, they have an impact on CO2, but emissions from
electricity usage and district heating in buildings have more impact than direct combustion in buildings.
In order to save energy people could do some stuff like turning off the electricity when it was not
necessary, unplugging their electronic devices when they were not using them instead of leaving them
on the standby mode or turn of the taps when they were brushing their teeth etc. But these types of
precautions were not enough for energy saving or reducing the carbon dioxide emission. As cities can
play a major role in climate change, some serious precautions have to be taken about structures. When
buildings are located on hazardous sites, they are exposed to high climatic risks. Non-sustainable
buildings are mostly located in cities and most of them have impact on environment from their building
stage to demolishment stage. According to Osman Balaban (2013); “Buildings are among the major
sources of excessive resource and energy consumption, and thereby carbon emissions in cities. Along
with one-third of global energy end use, the building sector is responsible for more than a third of
global resource consumption, including 12 per cent of all fresh water use, and generates approximately
40 per cent of the total volume of solid wastes in the world.” Therefore, there was a need for structural
change which was building sustainable (green) buildings. As Sir Winston Churchill said “We shape our
buildings; thereafter they shape us.” By changing the construction methods, construction materials,
systems that are used in the constructions etc., people can decrease the amount of CO2 emission and
energy consumption. There are two ways of doing that retrofitting traditional buildings or building
sustainable buildings.

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Traditional (non-sustainable) buildings
20 years ago, very few people had idea and knowledge about sustainable buildings. Global warming
was not a serious issue and almost no one had an idea about the impact of the buildings on the global
warming. Today; if you look around, you can easily see traditional buildings. Some people think that
buildings are dead steel or concrete bulks and they do not have any impact on the environment.
However this is not true. It is obvious that there are many other effects on climate change or air
pollution like vehicle gases, people’s garbage, chemical wastes etc. but people do not know that energy
consumptions of buildings have more impact on the environment than those factors.
For example; according to the website of State Environmental Resource Centre (2004), traditional
buildings consume or are responsible for:
• 45% of the world’s total energy use;
• 50% of all materials and resources;
• 50% of wood use in North America;
• 35% of the world’s CO2 emissions;
• 80% of potable water use;
• 25% of freshwater withdrawal (including power plants);
• 40% of municipal solid waste destined for local landfills;
• 50% of ozone-depleting Chlorofluorocarbons still in use.
Effects that are mentioned above can be lowered by using sustainable materials (systems) at traditional
buildings as they are buildings which have no technological system to lower the impact of the buildings
on the environment. These systems are electric systems, heating systems or water recycling systems and
as mentioned before, they have remarkable effect on energy consumption and CO2 emission values of
buildings.
Figure 3- Heat loss values of an uninsulated house
(http://www.sustainability.vic.gov.au/services-and-advice/households/energy-
efficiency/heating/retain-heat-in-your-home)
For heating energy of traditional houses, as they do not have any sustainable heating systems, they have
to be insulated well. Otherwise; as shown in Figure 3, heat loss will be very high compare to well
insulated houses. As a result, energy consumption values will be high as high heat loss means high
energy consumption for heating. Sometimes even high insulation may not be enough to lower heating
energy consumption. For example, in a very cold place outside temperature can be -15°C and as a

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healthy inside temperature of a building is 23°C for humankind, only isolation may not keep inside
temperature around 23°C. In that case, there is a need for powerful heating system and this system will
probably produce high CO2 emission than usual. However, if that building has a geothermal sustainable
system then by using water which has a ground temperature (lower than over ground temperature) for
heating, house holders can heat the area more easily and spend less energy with less CO2 emission. So,
this shows that long term energy consumption of a building depends on the materials and the systems
are used in the construction. Moreover, sustainable systems are good solutions in order to achieve good
results for energy consumptions.
Retrofit of traditional buildings in terms of energy consumption
People do not need to build sustainable buildings or demolish traditional ones in order to build
sustainable building. They can retrofit traditional buildings in order to convert them into a sustainable
building. There are different ways of lowering the energy consumption of traditional buildings.
Walls
As shown in Figure 3, walls cause 15-25% heat loss. In order to lower that value, isolation of the walls
has to be retrofitted well. First, heat loss values of the walls have to be checked. If values are acceptable
or appropriate for sustainable building regulations then there is no need for doing retrofit and spending
extra money. However, if heat loss values are not appropriate then required heat loss values of the walls
have to be calculated and according to that calculations walls have to be isolated again and if possible
high quality paints have to be used. As shown in Figure 4, thickest part of the wall is cavity insulation
part which has the highest effect on reduction of heat loss. Sometimes it may not be enough to examine
thermal processes in isolation particularly as the behaviour of moisture content of the traditional
buildings are different than modern buildings (Neil M. et al., 2012). Therefore, moisture content of
structure has to be known well in order to obtain maximum efficiency.
Figure 4 – Isolated wall sample
(http://web.ornl.gov/sci/roofs+walls/insulation/ins_05.html)

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Windows and doors
Windows and doors cause 10-20% of the heat loss of a building. For windows, three different types of
windows can be used single glazed (4.8-5.7𝑊/𝑚2 𝐾), double glazed (2.7𝑊/𝑚2 𝐾) or triple glazed
(1.6𝑊/𝑚2 𝐾) windows (Mizi F., 2011). From single glazed to triple glazed, insulation values increase
due to layers of the windows. As shown in Figure 5, gaps between windows act like isolation materials
and they reduce the heat loss of the structure. Also, if high quality plastic; like abs, is used then it can
decrease the heat loss more.
Figure 5 – Double glazed window sample
(http://britanniawindows.co.uk/triple-glazed-windows-in-somerset/)
Old windows have only frames and glass that is why their heat loss values are high. When outside
temperature is; let us say, 5°C and inside temperature is 20°C then as windows transfer the heat, outside
temperature will start to lower inside temperature around the windows (Mizi F., 2011). Probably
everyone have experienced before that during winter while heating is working and inside temperature is
in normal conditions, corners of the window frames and windows are colder than the inside
temperature. This is all about heat transfer of the windows. Therefore; in order to retrofit traditional
buildings, old windows can be changed. However; sometimes it may not be the most efficient way as
Neil M. et al. (2012) mentioned in Responsible Retrofit of Traditional Buildings academic paper.
According to Neil M. et al. (2012) “A secondary glazed historic window can reduce heat loss more
effectively than a replacement double glazed window. However, the effectiveness of secondary glazing
for traditional windows does not seem to have made its way into more mainstream refurbishment
literature which frequently only provides the message that replacing windows will save energy.” As
shown in Figure 6, secondary glazed windows are two single glazed windows that are built together
with two window frames. As they have more windows in total, they have more effect on heat loss.
However, most people do not prefer to use them as double glazed windows look better and easier to
use. To sum up, old windows can be retrofitted or converted into secondary glazed windows in order to
obtain high insulation.
Figure 6 – Secondary glazed window sample
(http://secondaryglazing.ie/images/secondary.gif)

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Floors
Floors have almost same heat loss values with windows and doors but there is not much to do about
heat loss throw floors. There are some heating systems which take place underneath the floor and work
as radiators. Those systems may be used as a radiator instead of using heaters and in that case energy
usage can be lowered. As shown in Figure 7, tubes are passing underneath the flooring and they include
hot water inside of them like normal radiator pipes. Also, there is an isolation material in order to reflect
the heat to the floor instead of letting it pass throw ground.
Figure 7 – Floor heating systems sample
(http://mcgrathplumbing.com/images/PexRadiant.jpg)
Day light saving and lighting
In order to lower the energy consumption of lighting systems, sustainable materials can be used and if
positions of the windows are not appropriate then in order to obtain maximum day light, they have to be
repositioned. For sustainable lighting, fluorescent bulb can be used instead of old bulbs or lamps. By
using fluorescent bulbs, energy consumption of the lights can be lowered around 40-60% depending on
the type of the bulb. Also; they are adjustable, in other words; user can adjust the level of the light and
therefore use less energy during day time. Fluorescent bulbs are also recyclable and eco-friendly. For
the positions of the windows; in order to obtain maximum day light during the day and to lower the
energy consumption, they have to be replaced according to the position of the building and sun. This
method is both beneficial for energy consumption and heating. When there is shadow inside the room,
room gets cold and dark. According to Mizi F. (2011) “Sunlight incident upon an internal building
surface and absorbed will raise the temperature of the surface. If the heat absorbed cannot be conducted
into the structure then it will further increase the surface temperature. This will increase the radiant
temperature of the room and also promote convection of heat into the room and increase the air
temperature.” To sum up; by calculating the position of the sun during day time, windows can be re-
positioned and maximum efficiency can be obtained.
There is a research done by Noyan Ulusarac in 2012 about the comparison of Brunel University’s
Lecture Centre building (traditional building) and Brunel University’s Eastern Gateway building
(sustainable building) with regards to their materials and system:
The two buildings constructed in different times with be examined with regards to discussing their
structures in terms of sustainability. Sustainability in both buildings will be addressed with regards to
their facade, frames, windows, isolation systems and benefit of daylight.

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Facade system:
Looking at the traditional building, one sees a building that is far from a sustainable building with
regards to its facade. The building’s facade is not present as finishing is only left with a concrete
surface. Hence, crucial damages could be observed as the concrete surface has worn over time causing
the reinforcing steel in the concrete to be exposed. This over time will cause the corrosion of the
exposed steel as it comes into contact with oxygen, which will then cause further rust and corrosion to
other steel elements in the concrete. Corrosion of reinforcing elements means the weakening of the
reinforcement which in turn leads to the building’s insufficiency to bear loads, thus decreasing its
operational life. In addition, the heat losses will increase in due course (See Fig. 13).
Whilst the traditional building is observed to be very inefficient in terms of sustainability, the
sustainable building is constructed with cladding as facade system or stucco-works to prevent corrosion.
Isolation materials are placed in between the cladding and the concrete surface behind in order to form a
system that prevents heat loss (Fig. 15-16-20)
Briefly:
 The traditional building does not have cladding over the concrete surface. It is vulnerable to
weathering action thus causing the building’s operational life to decrease through corrosion.
 The internal heat loss of the traditional building is at a maximum level due to the lack of
cladding on the concrete surface. The exchange of warm air to flow outside and cold air to flow
inside is therefore very easy which in turn means there has to be maximum energy consumption
in order to heat the building.
Frame, windows and isolation systems:
When the traditional building is examined with regards to frame, window and isolation systems, it is
evident that there is a poor heat isolation system as the walls are thin and the window frames are single
glazed (See Fig. 12 and 14). Thus, the lack of internal heat isolation is mainly due to major heat loss
through the frames. As the windows are single glazed, it is observed that there is a considerable heat
loss through the surface of windows.
Whilst poor isolation is observed in the traditional building, the sustainable building is far more
sustainable with regards to its frame, window and isolation system (See Fig. 16-17-19-20). The
isolation system here involves an aluminium frame with isolation material within. This enables a longer
operational life span and the heat loss is almost negligible. A quick observation on the windows shows
that the windows are double glazed. Double glazed windows prevent heat losses to a minimum. In
addition, the types of windows chosen are reflective which prevents internal heat loss through heat flow
from inside the building to outside during the winter months with regards to heat transfer coefficient.
This means that extreme radiation is prevented in the summer months which decrease the use of cooling
systems.
Briefly:
 As simple frame system is used in the traditional building, heat losses and heat transfers are at a
maximum level.
 Heat is lost and transferred easily in the traditional building as the windows are flat and single
glazed. This will cause the warm air to easily flow out and the cold air to easy flow in the
building during the winter months and the building will require an extensive cooling during the
summer months when the sunlight hits the windows directly. Overall, this will increase the
energy consumption for heating and cooling systems.
 The isolated frames in the sustainable building prevent these flows.

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 Reflective double glazed windows in the sustainable building prevent heat loss during winter
and the excess sunlight is blocked during the summer thus making the building cost-efficient in
terms of energy-grade.
Benefiting from Day Light
Upon observation of the architectural design of shared spaces and corridors of the traditional building
(Fig. 8-9-10), these areas are constantly in the lack of daylight and there is a constant need of lighting
system. This connotes inefficiency of energy use increasing costs as the users of the building are not
able to benefit from daylight.
However, it is observed that the shared spaces give a sense of integrity with the floor above and below
which enables maximum benefit of daylight (See Fig. 17). Thus, as the benefit from daylight is
maximised, the use of lighting systems is minimised which in turn saves the costs incurred for
electricity consumption.
Briefly:
 The traditional building is isolated from benefiting of daylight especially in shared spaces and
corridors. These areas are entirely surrounded by walls which prevent the benefit of daylight
and thus need constant lighting sources that consume a lot of energy.
 The architectural planning of the sustainable building is laid out in a way that the building can
benefit from daylight on a maximum level. This enables energy saving and less costs incurred
from electricity consumption.
Electric system:
As discussed earlier, the traditional building is inefficient in terms of benefiting from daylight as a
result of its architectural design. There is a manual use of electricity (switches) in order to provide
lighting to shared spaces and corridors. This means that these lights will remain on as long as someone
switches it off and when left on, the electricity consumption increases thus causing high electricity costs
(See Fig 8-9-10). This is an uncontrolled method of energy and requires a lot of energy and incurs a lot
of costs.
However, this is not the case in the sustainable building. The architectural design enables maximum
benefit of daylight in shared spaces, as energy is saved. In addition, motion and light sensors within the
building enables a controlled use of the electricity i.e. the lights turn on only when the sensors sense
activity in the area. This method enables a controlled manner of using energy, thus being cost-efficient
and also the light sources used are human friendly which works for human health.
Briefly:
 Energy saving is not considered in the traditional building as all lighting sources are turned on
and off manually.
 The light sources selected for the traditional building consume a lot of energy and harm human
vision.
 Energy saving in the sustainable building is thoroughly considered as sensors are present to
detect motion and light-dark changes.
 The lighting sources in the new building both consume low levels of energy and provide
maximum amount of light.

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Recommendations for the refurbishment of the traditional building
The refurbishment recommendations put forward for the traditional building with reference to the
comparison between the traditional and sustainable building with regards to materials, methods and
systems to be used are as follows:
 Firstly, the old facade, walls inside the building that are not load bearing structures, lights and
all mechanical infrastructure should be removed and cleaned until the main structural frame is
left with.
 An architectural plan should be carried out especially in shared spaces to enable maximum
daylight benefit.
 The reinforced concrete facade should be coated/covered/cladded with insulation material
against heat loss.
 Where windows exist, the frames should be of aluminium of that carry insulation properties.
 The windows should be double glazed with reflective properties. This will save the costs
incurred on cooling systems during summer months.
 HVAC system should be used i.e. a central heating and cooling system should be used which
also decreases carbon releases.
 Use of lighting systems that are sensitive to motion and daylight and time of day which will add
a lot to energy saving.
 A partial energy support could be acquired by the use of solar panels to benefit from the
daylight.
To sum up, there are lots of different ways to refurbish a traditional building. These refurbishment
methods are highly efficient in terms of energy consumption and heating. However, sustainable
buildings which are built directly as sustainable buildings are more efficient than both traditional
buildings and refurbished traditional buildings.
Traditional Building’s Photos: Brunel University’s Lecture Centre building
Figure 8 – Corridor of traditional building Figure 9- Lecture room of traditional building

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Figure 10- Ceiling of corridor Figure 11- Radiator in traditional building
Figure 12- Wall of traditional building Figure 13- Side wall of traditional building
Figure 14- Façade of traditional building

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Sustainable Building’s Photos: Eastern Gateway building
Figure 15- Outside of sustainable building Figure 16- Entrance of sustainable building
Figure 17- Windows of sustainable building Figure 18- Lighting of sustainable building
Figure 19- Windows of sustainable building Figure 20 – Windows of sustainable building

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In parallel to the previous research done by author, this academic research paper is carried out about the
critical assessment of the sustainable buildings in terms of energy consumptions and CO2 emissions.
The following section includes the previous researches done and information about them. After that;
research methodology section includes how necessary data is collected and how it is assessed. Then in
the results and discussion section collected data is assessed and their relationship between data in the
literature review is evaluated. In the last section which is conclusion all the parts are evaluated and main
conclusions are mentioned.
Main aim of this academic research paper is critical assessment of sustainable buildings in terms of
energy consumptions and CO2 emissions. Moreover, objectives of the academic research paper are:
 Assessment of benefits and limitations of sustainable building;
 Assessment of sustainable energy systems with their benefits and limitations;
 Assessment of differences between sustainable and traditional (non-sustainable) building;
 To prove that sustainable buildings are necessary for future.
LITERATURE REVIEW
What is sustainable building?
Green buildings are eco-friendly buildings; in other words, they have low impact on the environment
compare to the traditional buildings. They are an environmentally sustainable building, designed,
constructed and operated to minimise the total environmental impact. According to J. Cullen Howe
(2010), green building involves “The practice of increasing the efficiency with which buildings and
their sites use energy, water, and materials, and reducing building impacts on human health and the
environment, through better siting, design, construction, operation, maintenance, and removal—the
complete building life cycle.” The Governor’s Green Government Council (2005) defines a green
building as a building, “Whose construction and lifetime of operation assure the healthiest possible
environment while representing the most efficient and least disruptive use of land, water, energy and
resources.” John Smiciklas et al. (2012); in “Go Green” document, describes a green building as,
“Sustainable building refers to both the structure and a process that is more environmentally responsible
during the entire life cycle of a building.” The USEPA definition of a green building is “Green building
is the practice of creating structures and using processes that are environmentally responsible and
resource-efficient throughout a building's life-cycle from siting to design, construction, operation,
maintenance, renovation and deconstruction. This practice expands and complements the classical
building design concerns of economy, utility, durability, and comfort. Green building is also known as a
sustainable or high performance building.” Green or sustainable building is the practice of designing,
constructing, operating, maintaining, and removing buildings in ways that conserve natural resources
and reduce pollution.
There are four key principles that a green building has to achieve (Mizi F., 2011):
 Reducing embodied energy and resource depletion
 Reducing energy in use
 Minimising external pollution and environmental damage
 Minimising internal pollution and damage to health

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Application properties (Governor’s Green Government Council, 2005):
 Planning in accordance with green building standards in design stage and optimising costs
through basic and innovative solutions;
 Design that enables minimum earthworks and the use of waste materials;
 Energy saving through the development of sound and heat isolation through effective isolation
systems;
 Development of concepts through architectural methods that enables maximum natural light
into the building;
 Effective solutions for HVAC (heating, cooling and ventilation) systems;
 Use of cheap construction materials such as VOC (volatile organic compound) and decoration
products;
 Use of solar energy through photovoltaic panel systems i.e. producing electricity under the
influence of light or radiation and landscaping with trees;
 Use of motion detective sensors for ventilation and lighting systems;
 Development of buildings that can self-generate electricity;
 Use of Ground Source Heat Pump System – GSHP;
 Use of trombe wall in south end of building in order to obtain half of the heat energy required
during winter months from the sun.
Benefits of sustainable buildings
Economic: As sustainable buildings conserve resources and reuse or store them efficiently, they save
money. This efficiency is enhanced by (State Environmental Resource Centre, 2004):
 Using natural daylight and ventilation therefore minimizing energy consumption and
maximizing efficiency;
 Using sustainable systems for energy such as photovoltaic panels, solar panels, geothermal
heating systems;
 Using good (preferably natural) materials for insulation;
 Using sustainable systems like rain water harvesting systems or grey water recycling systems in
order to storage or reuse water and lower the consumption;
 Using geothermal systems or water heating system for heating both air and water.
Energy: Sustainable buildings have to be designed in order to use less energy than traditional buildings
and it is possible by using renewable energy sources and reducing both embodied and operating energy
consumption. Some ways of achieving that is (Governor’s Green Government Council, 2005):
 Using good isolation materials and high-performance windows in order to lower heat loss and
decrease the energy consumption for heating;
 Using solar panels, photovoltaic panels etc. in order to use the solar energy;
 Using wind turbines in order to convert mechanical energy into a kinetic energy and use or
store it;
 Placing the windows in the correct positions in order to obtain light from outside and lower
the necessity of the light usage.
Environment: As sustainable buildings use/reuse the natural sources efficiently and eco-friendly, they
have low impact on the environment. This impact is related with (State Environmental Resource Centre,
2004):
 Minimizing the use of the construction materials and reusing them;
 Lowering the CO2 emissions
 Reducing the chemical wastes carefully;
 Using recycling systems for wastes and used waters including rain water and grey water.

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Health & Safety: Sustainable buildings aim to reduce the impact of the construction sector on human
kind by (Governor’s Green Government Council, 2005):
 Eliminating harmful materials;
 Using low emission materials for example; for both internal and external walls zero VOC
paints, natural plasters (clay or hydraulic lime) and natural paints (lime paint, clay paint or milk
paint) etc.;
 Lowering CO2 consumption.
Value of the structure: Traditional buildings are expensive compare to the sustainable buildings which
is due to reduction at the usage of water, gas, energy etc. This is an advantage for both customer and
seller because for seller, she/he can earn more money and on the other hand for the customer, she/he
may pay too much money but in the end spending money will be earned back due to less spending on
water, gas or energy bills. In addition to that; if the sustainable buildings can be designed as a net zero
building which creates more energy than it spends, costumer can even earn money with the extra
energy.
Limitations of sustainable buildings
Cost: Sustainable materials or systems may cost too much and companies need to invest a lot of money.
The aim of the sustainable buildings is to regain the amount of money that is spent on those systems in
a certain time period. However, some companies are using Build-Operate-Transfer method for the
structures and sometimes they need to transfer the structure to another company before the estimated
time of regaining the spending on sustainable buildings. Therefore, they cannot regain their spending
back and sustainable systems can be considered as useless (Devin Saylor, 2012).
Time: Time is one of the main issues about a sustainable building. If construction is not completed on
time then this may cause additional fees and increase on the expenses. However, sometimes it can be
too difficult to find the proper material(s) for the sustainable building and this may cause delays and
therefore late penalties.
Roofs: Some sustainable structures have green roofs which include vegetation, isolation, drainage and
waterproofing membrane on them. Therefore; in order to support that heavy loading, roofs have to be
designed strong and this may cause extra expenses.
Materials: As mentioned before, sometimes it can be too difficult to find the proper material(s) and as a
result of this, materials have to be demand from other cities or countries. Transportation of those
materials may cause extra spending and extra time. Moreover, as materials are being transported by
trucks, planes or ships, it may cause extra CO2emissions.
Environment: Some sustainable buildings use recycled materials and recycle the materials being used.
These materials have to be collected and transferred to a recycling area each month and as it requires
trucks, it may cause traffic problems and air pollution if the construction area is in a city or a crowded
place (Governor’s Green Government Council, 2005).
Workers: In order to build a traditional building there is no need for highly qualified workers but on the
other hand in order to build a sustainable building there is a need for highly qualified workers who have
specific knowledge about sustainable systems, materials, regulation and management rules.
To sum up, sustainable buildings have lots of advantages and they are really efficient and eco-friendly.
They may have disadvantages besides advantages but disadvantages can be easily solved with a well
prepared project management plan (Devin Saylor, 2012).

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Cost in sustainable buildings
In order to count a building as a sustainable building, it should be selective in its design, structural
systems and construction materials which increase the cost. However, if the increase in value and
prestige of the building on top of the efficiency in energy consumption is considered then the cost loses
its substantiality against the benefits the green building provides. Accurate decisions and fundamentals
during the architectural design phase have high importance as those decisions and fundamentals will
change the building’s value. If possible, best way is to keep the cost at an optimum value. The increase
in the importance of green buildings put together with the widespread use will increase the preference
of this design. It is estimated that green buildings cumulate a cost increase of about 5-10% during the
construction phase. However, it has been observed that green buildings provide a cost-efficiency of up
to 25-30% (Gregory K., 2003). As mentioned before; on a long-term basis, green buildings present
important benefits as the operational costs are low.
Relationship between sustainable buildings and 𝐂𝐎 𝟐 emission
Global warming is a main issue in today’s world. It affects climate, atmosphere, temperature of the
earth and therefore our lives. One of the main reasons for global warming is CO2 emissions. It is being
caused by humans (their deodorants, materials etc.), transportation tools and their gasses (vehicles,
trains etc.), industries and buildings (materials being used, energy consumptions, demolitions etc.). This
part discusses CO2 emissions of the sustainable buildings and their relations with energy consumption.
Before that point brief information, examples and future plans about CO2 emission are going to be
given.
According to the Building and Climate Change article of the U.S Green Building Council (USGBC)
(2008), “Scientists predict that left unchecked, emissions of CO2 and other greenhouse gases from
human activities will raise global temperatures by 2.5ºF to 10ºF this century. The effects will be
profound, and may include rising sea levels, more frequent floods and droughts, and increased spread of
infectious diseases. To address the threat of climate change, greenhouse gas emissions must be slowed,
stopped, and reversed.” All these effects of the CO2 emission on climates called global warming as
temperature of the climate increases. It is because CO2 emissions are affecting the ozone layer which
prevents earth from negative effects of the Sun. If there was no ozone layer, Earth would be like Mars;
in other words, so hot and none of the creatures could survive as its CO2 amount is around 90% of its
atmosphere. Therefore, some precautions have to be taken in order to stop the global warming and save
our life and Earth.
Green buildings are really important about global warming as construction sector plays a huge role
about global warming. If effects of it can be changed, global warming can be slowed or even stopped.
For example, as it is mentioned by U.S Green Building Council (USGBC) (2008), “The commercial
and residential building sector accounts for 39% of carbon dioxide (CO2) emissions in the United States
per year, more than any other sector. Most of these emissions come from the combustion of fossil fuels
to provide heating, cooling and lighting, and to power appliances and electrical equipment. By
transforming the built environment to be more energy-efficient and climate-friendly, the building sector
can play a major role in reducing the threat of climate change.” Also; ASME (2009) mentioned that
“Since 1990, CO2 emissions have been increasing at almost 2 percent a year primarily due to sector
growth. Because buildings are one of the longest-lived assets, their initial design and construction
practices can long impact future energy consumption and efficiency options.” This shows that if
buildings are being built environmental friendly then as they stay for a long time they can have a good
effect on the atmosphere and CO2 emission as long as they stay.

21
There are some good examples about CO2 emission of the constructions and their amounts. For
example, as U.S Green Building Council (USGBC) (2008) mentioned, “In 2004, total emissions from
residential and commercial buildings were 2236 million metric tons of CO2, or 39% of total U.S. CO2
emissions which were more than either the transportation or industrial sectors.”
Gases that are being released from constructions are called Carbon Footprint. It is basically the total
amount of the greenhouse gases emissions caused by life-cycle of the construction from its material
transportation stage to the demolishment stage. There are four different types of greenhouse gases that
have to be controlled; carbon dioxide, methane, nitrous oxide and sulphur hexafluoride. The carbon
footprint is based on the mass of carbon dioxide (CO2) in kilograms or metric tons as carbon is the most
common of the greenhouse gases (GHGs) emitted by humans (Express Towers, 2010). As UNEP SBCI
(2009) mentioned that “The environmental footprint of the building sector includes; 40% of energy use,
30% raw materials use, 25% of solid waste, 25% water use, and 12% of land use.” Therefore, most of
the precautions have to be taken about energy usage of the buildings.
Some strict precautions have started to be taken from companies, governments, householders etc. Lots
of companies are founded just to heal the conditions of the building and/or building eco-friendly ones.
According to Diana V. et al., “The calculations suggest that, globally, by 2020, approximately 29% of
the business-as-usual CO2 equivalent emissions or about 3.2 billion tons of CO2 equivalents can be
avoided annually in a cost-effective way through mitigation measures in the residential and commercial
sectors.”
As mentioned before, electricity usage of the constructions are playing a major role at CO2 emission.
According to the ASME (2009), “Typically, over 80% of the life cycle energy use is associated with
operation of the building rather than construction or renovation (including material manufacturing and
transport).” Also; as International Energy Agency (2013) mentioned, “The buildings sector is the largest
energy-consuming sector, accounting for over one-third of final energy consumption globally and an
equally important source of carbon dioxide (CO2) emissions. In certain regions highly dependent on
traditional biomass, energy use in buildings represents as much as 80% of total final energy use.”
Moreover, according to Diana V. et al. (2007), “Energy use in the buildings sector was responsible for
7.85 Gt carbon dioxide (CO2) emissions in 2002, 33% of the global total of energy-related emissions.
Buildings were also responsible for approximately 1.5 Gt CO2 equivalent emissions from fluorinated
gases. The commonly used IPCC Special Report on Emissions Scenarios (SRES) scenarios project
growth of these emissions to 11 Gt and 15.6 Gt CO2 by 2030 (Nakic´enovic´ et al., 2000), with the
share of the sector remaining at approximately 34% of the total.” However, sustainable buildings can be
a good solution for this problem. For example, according to the U.S Green Building Council (USGBC)
(2008), “The average LEED certified building uses 32% less electricity and saves 350 metric tons of
CO2 emissions annually. The building sector consumed 40 quadrillion Btus of energy in 2005 at a cost
of over $300 billion. Energy use in the sector is projected to increase to 50 quadrillion Btus at a cost of
$430 billion by the year 2025.” This shows that sustainability can save both energy and money.
A case study which is shown in Figure 21 is based on a study done in 1999 and mentioned by Express
Towers (2010) shows that electricity generation and carbon emissions across 3 countries. According to
the graph, coal has the highest carbon emission per kg while hydroelectricity and nuclear energy have
the lowest. Therefore, systems which require coal have to be changed into solar PV, wind, nuclear or
hydroelectric systems in order to lower the CO2 emission. However, nuclear power can be dangerous
sometimes and not that applicable for sustainable buildings; therefore, other systems have to be used.

22
Figure 21 – Carbon Emissions for Electricity Generation per Vattenfall 1999 (Express Towers, 2010)
If precautions were taken before, results could be different. For example; according to the U.S Green
Building Council (USGBC) (2008), “Buildings have a lifespan of 50-100 years during which they
continually consume energy and produce CO2emissions. If half of new commercial buildings were built
to use 50% less energy, it would save over 6 million metric tons of CO2 annually for the life of the
buildings, the equivalent of taking more than 1 million cars off the road every year.” Today, there are
different types of low-energy houses are being built which are passive houses, zero energy homes, self-
sufficient houses etc. Main aim of these types of houses is to minimize the final energy use (Leif
Gustavsson et al., 2009).
There are future plans about CO2 emissions. According to ASME (2009), “The U.S. Department of
Energy has estimated that by 2050, with advances in building envelopes, equipment, and systems
integration, it may be possible to achieve up to a 70 percent reduction in a building’s energy use,
compared with the average energy use in an equivalent building today.” So, it is not too late to lower
the energy consumption and CO2 emission and save the climate and planet Earth.
Relationship between energy consumptions of sustainable buildings and 𝐂𝐎 𝟐 emission
Nowadays people are using energy for almost everything but it is not easy to obtain energy from natural
or artificial sources. Most of this energy is being used in the structures for lights, elevators, radiators,
electric plugs, machines etc. However, sustainable buildings aim to reduce this usage. There are some
applications of renewable energy sources such as solar systems and geothermal systems.
1-Solar Systems: By using solar systems; such as photovoltaic devices or thermal collectors, solar
energy can be obtained and converted into electricity in order to heat water, to power lights, to use
electronic devices and to build a sustainable future. Moreover; electricity and heat can offset utility
costs and reduce, or even eliminate, the need for water heaters.
Photovoltaic (PV) energy
The word “photovoltaic” is a combination of two words “photo” and “voltaic” (Pacific Northwest
National Laboratory & Oak Ridge National Laboratory, 2007). Photo means light and voltaic means
voltage. Photovoltaic systems are using photovoltaic cells which convert sunlight into electricity
directly. These energy systems can be used on the ground or in the design of the structure. There are
some good examples for ground type photovoltaic energy systems in hot places like Las Vegas. There
are lots of buildings in Las Vegas and all the machines (hotel elevators, gamble machines etc.) are
working almost 24/7 and using lots of energy. Therefore; one of the world’s largest photovoltaic
systems are being built near Las Vegas. This project is called ‘Nevada Power 3.1MW Solar Project’.

23
According to the power-technology’s website (2005); “Over their 30-year operating life, the systems
will generate clean electricity and save the equivalent of 5.8 million barrels of oil. The project uses no
water, and is emission free. A key solar benefit is that maximum power is developed during summer,
when electricity use is at its highest and state transmission lines are the most constrained. By avoiding
hundreds of tons of carbon dioxide emissions, it is equivalent to planting 1,320 acres of trees or saving
on 350 million miles worth of car journeys.” As Las Vegas project requires lots of panels, they have to
be placed on the ground rather than top of the buildings. However, they were requiring an additional
space (land) and those systems are harming the birds which are flying around that area as panels
increase the temperature of the area by reflecting the light of the sun and sometimes that temperature
may reach more than 100 centigrade degrees. If there is not an extra space for systems then photovoltaic
systems which take place in the design of the structure can be used. They can be located at the terrace,
roof and facade or even at the parts of the structure. For example, as Tjerk H. Reijenga (2003)
mentioned, “In countries such as Denmark, the Netherlands and the United Kingdom, where public
housing is very common, serial production is strongly emphasized in housing projects. Professionals
such as project developers and architects implement the housing construction process, in which the
main opportunities are for PV roof integration in single-family terraced houses and for facade and roof
integration in apartment buildings.” Sometimes it is more efficient to integrate a PV system rather than
mounting it afterwards. It is because, when system is integrated while construction it has the advantage
of good calibration and good combination with the design of the structure. According to Tjerk H.
Reijenga (2003), “The aim of integrating PV systems into buildings is to reduce the requirement for
land and the costs. This could be the cost of the support construction and the cost of building elements,
such as tiles. It is more efficient to integrate a PV system when constructing the building, rather than
mounting it afterwards.” Moreover, according to IRENA (2012), photovoltaic panels have an efficiency
of 4-19% depending on the materials used at solar panels.
PV systems can also be used as heating material for space or water while being used for creating
energy. According to Tjerk H. Reijenga (2003), “At the project “Haus der Zukunft” in Linz (AT), an air
cavity has been created underneath the PV modules, through which warm air (heated by PV modules) is
exhausted. The hybrid collector provides warm air to the heating system in the home, which in this
case, makes it a cost-effective use of the collector.”
As shown in the Figure 22, PV systems can also be used as a shade systems if they can change position
(tilt) or replaced correctly according to the changes of the angles of the sun lights during the year.
Otherwise, it is not efficient during winter.
Figure 22: Shading system with high angle (summer) and low angle (winter), Tjerk H. Reijenga (2003)
Advantages of the grid-connected PV systems (Tjerk H. Reijenga (2003)):
• There is no additional requirement for land;
• The cost of the PV wall or roof can be offset against the cost of the building element it replaces;
• Power is generated on site and replaces electricity that would otherwise be purchased at commercial
rates;
• Connecting to the grid means that the high cost of storage is avoided and security of supply is ensured.

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Solar thermal energy
According to European Solar Thermal Technology Platform (2009); “During the coming years and
decades, fossil fuels and nuclear power will become increasingly scarce and expensive as a result of the
exhaustion of natural resources and the climate change mitigation policies. This process has obviously
already started. Therefore, using fossil fuels or electricity as the main resource to achieve the low
temperatures required for heating and cooling buildings will become too expensive for most people and
will be seen as an unacceptable squandering of resources. Certainly, the use of biomass and heat pumps
will rise significantly. However, scarce biomass resources are needed to fulfil the demand from other
energy and non-energy fields, while a wide deployment of heat pumps as a main source of heating
would imply a massive increase in electricity consumption, with strong economic and environmental
external costs. Therefore, solar thermal (ST) will become an indispensable and crucial pillar of the
future energy mix for heating and cooling.”
As William T. Guiney (2012) mentioned, “In the past 15 years, product research and development and
improved manufacturing have created a new generation of simple, reliable, efficient solar water heating
systems. Modelling tools are available to predict system performance, costs, energy savings and return
on investment based on local sun and weather conditions. In fact, solar water heating has the potential
to be the largest contributor in the next growth era of renewable energy and emission reductions.” Solar
thermal energy sources have high efficiency on the energy saving. In today’s world lots of sustainable
buildings are using solar thermal energy sources rather than using any other energy sources for
sustainability. Market of solar thermal energy sources growing day by day parallel to the usage of the
systems. According to William T. Guiney (2012) “Solar heating helps users diversify their energy
supplies and reduce dependence on imported fuels with volatile pricing. Solar systems can meet 50
percent of a typical facility’s hot-water heating load and may meet up to 80 percent. Even in northern
climates during winter, systems can provide 20 percent or more of water heating requirements.”
Moreover; according to European Solar Thermal Technology Platform (2009), “ST is becoming more
and more popular in a growing number of countries worldwide. The worldwide market for ST systems
has been growing continuously since the beginning of the 1990s. In Europe, the market size nearly
tripled between 2002 and 2006. Even in the leading European ST markets Austria, Greece and
Germany, only a minor part of the residential homes are using ST. In Germany, about 5% of one and
two family homes are using ST energy.”
In order to understand; why solar thermal energy sources are that much effective, than key reasons have
to be inspected. According to Gerhard F. (2010), “The products are reliable and have a high technical
standard. Key reasons for the utilisation of solar heat are: The energy need for heating and cooling, for
crop drying and for process heating is large and growing; the solar resource is large and inexhaustible;
the environmental benefits and the economic benefits are substantial.” Therefore; compare to the other
energy sources like photovoltaic panels, wind turbines etc., solar thermal energy sources are useful in
many activities. For example, difference between the solar thermal technology and solar photovoltaic
panels is that they are mainly producing heat energy whereas photovoltaic panels are producing
electricity. According to Solar Thermal Fact Sheet of Harvard Green Campus Initiative (2008), “Solar
thermal applications can provide energy for domestic hot water, space conditioning (heating or
cooling), or even electricity.” But they are mainly being used for heating water. As Gerhard Stryi-Hipp
et al. (2013) mentioned, “The primary solar thermal application is domestic hot water heating (DHW)
for residential homes, since the temperature level needed is moderate (45°C to 60°C) and DHW is
needed during throughout the year. Solar assisted space heating systems and process heat applications
for low temperature up to 95°C, as well as for medium temperatures up to 250°C or high temperature
up to 400°C, are later developments.”
For sustainable structures and systems CO2 emission has importance as much as being cost efficient or
even more. Therefore, materials are being used in the sustainable constructions have to effect on carbon
reduction. Solar thermal panels are really good at this point. As European Solar Thermal Technology
Platform (2009) mentioned in the “Solar Heating and Cooling for a Sustainable Energy Future in
Europe” document, “The independent Global Climate Decision Makers Survey (GCDMS, 2007)

25
presented in December, 2007 at the UN Climate Change conference in Bali showed that, among
approximately 20 carbon reduction technology options, solar thermal and passive solar are considered
over the next 25 years to be technologies with the highest carbon reduction potential without
unacceptable side effects.” There is a good example for that in William T. Guiney’s White Paper Solar
Thermal Energy (2012) document “A commercial solar water heating system with 500 square feet of
collector will displace the hot water generated by a small natural-gas-fired boiler, generating 2,281
therms per year and offsetting more than 26,825 pounds of CO2.”
Heating water, a place or a space cost lots of money. Almost every structure which includes people
inside needs heating. Therefore, there is a huge demand on the world’s total energy and money for
heating. As mentioned at European Solar Thermal Technology Platform (2009), “Heating accounts for a
significant proportion of the world’s total energy demand. The building sector alone consumes 35.3%,
of which 75% is for space heating and domestic water heating (IEA, 2006). Besides buildings, there is
substantial heat consumption for industrial processes and heat-intensive services. In Europe, the final
energy demand for heating and cooling (49%) is higher than for electricity (20%) or transport (31%)
(EREC, 2006).”
Figure 23 – In Europe Final Energy Demand, European Solar Thermal Technology Platform (2009)
Within the RES portfolio, ST has unique and specific benefits (European Solar Thermal Technology
Platform, 2009):
• ST always leads to a direct reduction of primary energy consumption;
• ST can be combined with nearly all kinds of back-up heat sources;
• ST has the highest potential under the RES-H/C-technologies and does not rely on finite resources,
needed also for other energy and non-energy purposes;
• ST does not lead to a significant increase in electricity demand, which could imply substantial
investments to increase power generation and transmission capacities;
• ST prices are highly predictable, since the largest part of them occur at the moment of investment, and
therefore does not depend on future oil, gas, biomass, or electricity prices;
• The life-cycle environmental impact of ST systems is extremely low.
Geothermal systems
Geothermal systems use the natural warmth of the ground to heat and cool the building. Nearly half of
the solar energy that reaches the earth remains stored in the ground at a constant about 13°C to 27°C
depending on the location of the structure. These systems provide heat in the winter and cooling in the
summer. According to J. Lund et al. (2004), “Geothermal heat pumps use the relatively constant
temperature of the earth to provide heating, cooling and domestic hot water for homes, schools,
government buildings and commercial buildings. A small amount of electricity input is required to run a
compressor; however, the energy output is of the order of four times this input.” Earth has an important
role on geothermal systems. For example, during summer when upper part of the earth’s surface is hot,
underneath of the surface is cold. As U.S Department of Energy (2011) mentioned, “While many parts
of the country experience seasonal temperature extremes – from scorching heat in the summer to sub-

26
zero cold in the winter – a few feet below the earth’s surface the ground remains a relatively constant
temperature. The natural ground temperature is cooler than the natural air temperature in summer and
warmer than the natural air temperature in winter.” When it gets hot outside, thermal heat pumps collect
heat from building and pumps it to the cool earth then turns that into the building in order to cool the
building. Geothermal pump is twice as efficient as air conditioner or air to air heat pumps. As
geothermal heat pumps pump the heat to or from the earth and it does not contain any chemicals, it has
no impact on the environment. Moreover, it is easy to transport and operate.
Geothermal systems consists three main parts heat exchanger (loop of pipes which is located at the
outside), heat pipe (mostly located in the building) and forced air system or radiant flow hydraulic
heating system. As shown in the Figure 24, loops take place under the ground and they can be replaced
in three different ways according to the ground conditions and location of the structure vertical to the
ground, horizontal to the ground or it can be replaced in a pond.
Figure 24 – Geothermal System, Website of the Popular Mechanics
(http://www.popularmechanics.com/science/energy/hydropower-geothermal/4331401)
Therefore, geothermal systems are durable and highly reliable as they are highly isolated from the
outside effects like dirt, particles and any effect that can damage the system. As Office of Geothermal
Technologies (1999) mentioned, “The underground piping used in the system often has 25- to 50- year
warranties, and the GHPs themselves typically last 20 years or more.” Therefore, they require low
maintenance which means less extra expense.
Usage of geothermal systems for structures is increasing day by day as systems easily retrieve the
amount that is being paid for system and they need less extra expenses because of less maintenance
requirements. According to J. Lund et al. (2004), “Geothermal (ground-source) heat pumps (GHPs) are
one of the fastest growing applications of renewable energy in the world, with annual increases of 10%
in about 30 countries over the past 10 years. Its main advantage is that it uses normal ground or
groundwater temperatures (between about 5 and 30 Celsius), which are available in all countries of the
world. Most of this growth has occurred in the United States and Europe, though interest is developing
in other countries such as Japan and Turkey. The present worldwide installed capacity is estimated at
almost 12,000 MWt (thermal) and the annual energy use is about 72,000 TJ (20,000 GWh). The actual
number of installed units is around 1,100,000, but the data are incomplete.” According to Office of
Geothermal Technologies (1999), “Ground-source (geothermal) heat pumps provide many benefits to
the homeowner in both new and retrofit situations. Surveys by utilities illustrate a high level of
satisfaction with GHPs compared to conventional systems. In fact, more than 95% of all GHP users
would recommend a similar system to their friends and family.”
Today many buildings are using these systems and it is worldwide. For example, according to J. Lund
et al. (2004), “In the United States, GHP installations have steadily increased over the past 10 years
with an annual growth rate of about 12%, mostly in the mid-western and eastern states from North
Dakota to Florida. Today, approximately 80,000 units are installed annually, of which 46% are vertical

27
closed loop systems, 38% horizontal closed loops systems and 15% open loop systems. Over 600
schools have installed these units for heating and cooling, especially in Texas. It should be noted at this
point, that in the United States, heat pumps are rated on tonnage and is equal to 12,000 Btu/hr or 3.51
kW (Kavanaugh and Rafferty, 1997). A unit for a typical residential requirement would be around three
tons or 10.5 kW installed capacity. One of the largest GHP installations in the United States is at the
Galt House East Hotel in Louisville, Kentucky. Heat and air conditioning is provided by GHPs for 600
hotel rooms, 100 apartments,and 89,000 square meters of office space for a total area of 161,650 square
meters. The GHPs use 177 L/s from four wells at 14EC, providing 15.8 MW of cooling and 19.6 MW
of heating capacity. The energy consumed is approximately 53% of an adjacent similar non-GHP
building, saving $25,000 per month.”
Some case studies being done about geothermal heating systems in U.S. of America (Office of
Geothermal Technologies, 1999):
Case Study—Minnesota
“Located in the middle of Minnesota—where temperatures can range from 90°F (32.2°C) with 95%
humidity in the summer to -18°F (-27.8°C) in the winter—Dennis Eichinger’s 3,400-square-foot home
averages a little over $44 per month in electricity bills. The owner has been very satisfied with the
unit’s quietness, high quality, reliability, and low maintenance. House guests also marvel at the comfort
level of the house—they don’t feel any drafts, just an even temperature throughout the house. The five-
ton ground source heat exchanger connects to five horizontal Slinky™ loops, totalling 3,000 feet of
pipe, buried next to the home at a depth of eight feet (2.4 meters). GHP technology heats and cools as
well as, or better than, conventional systems, even in Minnesota’s extreme temperatures.”
Case Study—Florida
“Panama City, Florida, homeowner Keith Swilley partnered with his builder and local electric utility to
create a 2,000- square-foot home that’s a model of efficiency. It saves so much energy that the home
won the 1997 Energy Value Housing Award for the custom home category for hot/humid climates at
the National Association of Home Builders Conference in Houston. Mr. Swilley used energy-efficient
features from ceiling to floor, with cellulose insulation in the walls and attics, sealed ductwork, and
efficient doors, windows, and lighting. However, the feature that saves the most energy is the
GeoExchange system. The geothermal heat pump heats and cools the house and provides hot water for
the residents with a desuperheater, which takes waste heat from the air-conditioning process and uses it
in the water heater. The desuperheater actually helps the GeoExchange unit reach heightened levels of
efficiency. The system was metered separately and has proven to be a valuable investment, as the
home’s total energy bill for 1996 was $906. Amazingly, only $253 of the total annual energy bill was
used for heating and cooling the 2,000 square feet of conditioned space. “The energy bills are even
lower than I anticipated,” said Mr. Swilley, “and the comfort level in the winter and summer is much
greater than expected. I never dreamed I could heat and cool my home for 69 cents a day”.
Wind turbines
Wind turbines basically turn wind energy (kinetic energy) into an electrical energy (static energy). They
do not emit any CO2 as they are not using fossil fuels. Also, they recover their total energy use to build,
operate and dismantle within the first few months of operation (World Steel Association, 2012). Most
of the wind turbines are being used in windy places to obtain high efficiency. There are two ways of
using wind turbines. One method is on an actual design of a building as shown in Figure 25. Other
method is placing wind turbines on the ground of the site area if building’s architecture (design) is not
suitable to place wind turbines. Some wind turbines may be big and heavy; therefore, they have to be
placed to the ground. On the other hand, it is possible to build them by using carbon fibre or alloys in
order to decrease their weight and increase their strength for strong winds (World Steel Association,
2012). However; in that case they may be more expensive than normal; therefore, they may not as
preferable as other energy systems.

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Figure 25 – Mechanism of a wind turbine, Alternative Energy Tutorials website
(http://www.alternative-energy-tutorials.com/images/stories/wind/alt53.gif)
Figure 25 shown above represents the mechanism of a wind turbine. As mentioned before it turns wind
energy (kinetic energy) into a static energy. Wind turns the rotor blades and this rotation drives the shaft
which is connected to the main gearbox. This gearbox is like gear box of a car. It includes gears inside
with various sizes. When rotor blades turn, they turn gears. Therefore, it charges the generator. Today’s
largest wind turbines can supply enough electricity to power 5,000 household (Alstom, 2014) and have
an average life span around 20 years (URS Group, 2010). However; wind turbines are not working with
a wind which is lower than 10 km/h. In order to obtain the maximum efficiency, wind turbines rotate to
the wind’s direction. Modern wind turbines operate with efficiency in the range of 20 to 50% (Alstom,
2014).
Figure 26 – The Bahrain World Trade Centre, My Modern Met website
(http://www.mymodernmet.com/profiles/blogs/what-big-wind-turbines-you)
A good examples of sustainable wind turbines is the one used at Bahrain World Trade Centre; shown in
the Figure 26, has three massive wind-turbines between twin towers. According to the Alternative
Energy News website “The buildings are the tallest in Manama and the turbines officially make it the
world’s first wind-powered mega structure. The three wind turbines are horizontally supported between
the towers by three bridges weighing substantial 65-tonnes each, and will provide 11-15% of the
electricity needs of both towers. ” Compare to Alstom’s (2014) claim, this wind turbines are not
efficient enough.
Information about sustainable building regulations
There are some regulations about green (sustainable) buildings like BREEAM, LEED etc. Each country
has its own regulation about buildings. These regulations stipulate different rules about materials,
equipment, systems and other issues. Around the world there are more than 35 countries using these
regulations for green buildings, which shows that global awareness is arising.

29
Some examples of sustainability regulations:
LEED
According to the U.S. Green Building Council (USGBC); LEED (Leadership in Energy &
Environmental Design) is “a green building tool that addresses the entire building lifecycle recognizing
best-in-class building strategies.” LEED has some criterions about structures and if those structures
fulfil the requirements of the LEED criterions they can be called as sustainable buildings and they can
have the LEED certificate. There are four certification levels: Certified, Silver, Gold, and Platinum.
Table 1: LEED certificate levels and points
Certification Levels LEED for Non-home
Structures
LEED for Homes
(*These point thresholds may
change based on home size.)
Certified: 40-49 points earned 45+ points earned
Silver: 50-59 points earned 60+ points earned
Gold: 60-79 points earned 75+ points earned
Platinum: 80+ points earned 90+ points earned
The LEED possible rating is as follows:
 Water Efficiency (10 possible points)
 Energy and Atmosphere (35 possible points)
 Materials and Resources (14 possible points)
 Innovation and Design Process (6 possible points)
 Indoor Environmental Quality (15 possible points)
 Sustainable sites (26 possible points)
According to Alireza et al. (2013), in order to obtain the LEED certificate “At first, to commence the
process of certification review, the required documents shall be submitted to the relevant regional Green
Building Council. Thereafter, six or eight credits will be selected to perform the audit. The council then
asks for submission of a report with special information on the selected credits. The final decision will
be made by the council to award the LEED certification.”
BREEAM
According to the BREEAM New Construction technical manual book (2011), “BREEAM (Building
Research Establishment’s Environmental Assessment Method) is the world’s leading and most widely
used environmental assessment method for buildings. BREEAM has certified over 200,000 buildings
since it was first launched in 1990.”

30
Aims of BREEAM according to the BREEAM New Construction Non-Domestic Buildings Technical
Manual (2011);
1. To mitigate the life cycle impacts of buildings on the environment;
2. To enable buildings to be recognised according to their environmental benefits;
3. To provide a credible, environmental label for buildings;
4. To stimulate demand for sustainable buildings.
Objectives of BREEAM according to the BREEAM New Construction Non-Domestic Buildings
Technical Manual (2011);
1. To provide market recognition of buildings with a low environmental impact;
2. To ensure best environmental practice is incorporated in building planning, design,
construction and operation;
3. To define a robust, cost-effective performance standard surpassing that required by
regulations;
4. To challenge the markettoprovide innovative,costeffective solutions that minimise the
environmental impact of buildings;
5. To raise the awareness amongst owners, occupants, designers and operators of the
benefits of buildings with a reduced life cycle impact on the environment;
6. To allow organisations to demonstrate progress towards corporate environmental
objectives.
Table 2: BREEAM certification levels
BREEAM benchmarks for new constructions
( According to the 2011 version of BREEAM)
% score
OUTSTANDING ≥85
EXCELLENT ≥70
VERY GOOD ≥55
GOOD ≥45
PASS ≥30
UNCLASSIFIED <30
The BREEAM possible rating is as follows:
 Management (12%)
 Health & Wellbeing (15%)
 Energy (19%)
 Transport (8%)
 Water (6%)
 Materials (12.5%)
 Waste (7.5%)
 Land Use & Ecology (10%)
 Pollution (10%)
In total it is 100% and also there is an additional weighting which is innovation (10%). The credit of the
building is being designated according to specifications of the building regarding to the rating given
above.

31
Sustainability in today’s world
Today, sustainability is more than being a must. It is kind of competition as a business for some firms.
They are trying to improve it as much as they can and find new sustainable ways, materials and systems
for buildings. Levels of green building activity by firms around the world between 2009 and 2015 and
also percentage of firms with more than 60% of work green between 2012 and 2015 bar graphs are
shown below.
Figure 27- Levels of Green Building Activity Figure 28- Percentage of More Than 60 of Work Green
Source: Harvey M. Bernstein (2013), ‘McGraw-Hill Construction Smart Market Report’
Moreover, according to Diana V. et al. (2007), “Implementing carbon mitigation options in buildings is
associated with a wide range of ancillary benefits. These include the creation of jobs and business
opportunities, increased economic competitiveness and energy security, social welfare benefits for low
income households, increased access to energy services, improved indoor and outdoor air quality, as
well as increased comfort, health and quality of life.”
To sum up, sustainable buildings are changing our life and our world. Day by day parallel to the
technology and demands, sustainable materials are improving. Global awareness about global warming
and energy consumption is increasing. Even if there is a long way to go about sustainability, today’s
and previous achievements are pretty good and useful. In the next chapter, interviews and questionnaire
results will be assessed.

32
RESEARCH METHODOLOGY
There are some research methods:
 Self-completionquestionnaire (multiple choice,commentsetc.)
 Structuredinterviewswithquestions(face toface)
 Structuredobservations
 In-depthinterviews(recordingthe interviews)
 Focusgroups (several participantsinonce byusingmoderator)
 Participantobservations
This research aims to critically assess sustainable buildings in terms of energy efficiency and CO2
emissions. Research is descriptive including some numerical data. Data were being collected by
structured interviews and self-completion questionnaires; as they are good for collecting data on topics
and for gaining a general overview of issues, in order to obtain the needed information. Moreover, 7
traditional (non-sustainable) and 5 sustainable buildings were assessed in terms of CO2 emission values,
energy consumptions and energy efficiency materials which are being used. Collected data were both
qualitative and quantitative. Other methods were not useful or not appropriate for this research.
More than 20 questions were asked to the participants (see appendix for sample). Questions are
prepared according to the topics of the literature review. They were mostly related with sustainable
building materials, management issues, effects of the sustainable buildings, regulations and
certifications. Participants were informed about the topic of the research to focus on energy
consumption and CO2 emission parts. Extra questions were asked in order to understand the awareness
of the sustainable buildings and future of the sustainable buildings. 3 weeks were given to the
participants to complete the questionnaires as there were more than 20 questions.
Of the 15 people asked to fill the questionnaires, 12 of them completed fully, 2 of them did not attempt
to fill at all and 1 of them couldn’t finish filling the questionnaire. 6 of the participants were project
managers, 3 of them were technicians and 3 of them were construction site controllers.
For sustainable buildings, energy consumption data, sustainable energy systems which are used in the
buildings and CO2 emissions of the buildings are directly obtained from the companies which
constructed the buildings and the data is used with the permission by informing the companies about
this paper. For traditional (non-sustainable) buildings data were obtained from the certifications of the
buildings. Those certifications were given by Department for Communities and Local Government
(DCLG) and they include both energy consumption values and CO2 emissions of the buildings.
The collected data was organised according to the questions. Topic related questions were separated and
rest of them which were about sustainability materials, regulations and certification were organised in
order to understand the awareness of the participants about sustainable buildings and their ideas about
future of the sustainable buildings.
Results were presented according to the responses from participants on 5 major topics; awareness of the
sustainable buildings, energy consumption results of the sustainable buildings, energy efficiency
materials at the sustainable buildings, CO2 emissions of the sustainable buildings and future of the
sustainable buildings. Assessments of these are shown in tables in the next chapter and explanations of
the values were given before each table.
In order to improve the results, more participants could take part and more people from other nations
could answer the questionnaire in order to make results more global. Moreover, more than 12 buildings
could be assessed. However; as there were a limit on time and page amount, those mentioned
improvements could not be achieved.

33
Critical assessment of research methods
Questionnaires:
Advantages (John M., 1998)
 The responses are gathered in a standardized way, so questionnaires are more objective,
certainly more so than interviews.
 Generally it is relatively quick to collect information using a questionnaire. However in some
situations they can take a long time not only to design but also to apply and analyze (see
disadvantages for more information).
 Potentially information can be collected from a large portion of a group. This potential is not
often realized, as returns from questionnaires are usually low. However return rates can be
dramatically improved if the questionnaire is delivered and responded to in class time.
Disadvantages (John M., 1998)
 Questionnaires, like many evaluation methods occur after the event, so participants may forget
important issues.
 Questionnaires are standardized so it is not possible to explain any points in the questions that
participants might misinterpret. This could be partially solved by piloting the questions on a
small group of students or at least friends and colleagues. It is advisable to do this anyway.
 Open-ended questions can generate large amounts of data that can take a long time to process
and analyze. One way of limiting this would be to limit the space available to students so their
responses are concise or to sample the students and survey only a portion of them.
 Respondents may answer superficially especially if the questionnaire takes a long time to
complete. The common mistake of asking too many questions should be avoided.
 Students may not be willing to answer the questions. They might not wish to reveal the
information or they might think that they will not benefit from responding perhaps even be
penalized by giving their real opinion. Students should be told why the information is being
collected and how the results will be beneficial. They should be asked to reply honestly and told
that if their response is negative this is just as useful as a more positive opinion. If possible the
questionnaire should be anonymous.
In addition to the above information, for this academic paper as time was limited to collect the data,
questionnaires are prepared before the writing stage; however, at the end author decided to change the
topic of the thesis little bit but this happened after questionnaires are sent to the participants. Therefore,
participants have answered all the questions are given to them and author had to ignore unrelated
questions with the new topic. As at the beginning there were lots of questions about sustainable
buildings, some of the participants decided to give up as they had no time to answer the questions. To
sum up, as it is not possible to change the questions after sending the questionnaires to the participants
and this is one of the biggest difference between interview and questionnaires. That is why in addition
to the questionnaires some interviews are arranged with the participants who had time and questions of
the questionnaires are asked at the interviews.
Interviews:
Advantages (WBI Evaluation Group, 2007)
 Interviews typically allow for more focused discussions and follow‐up questions;
 Individuals may offer information in interviews that they wouldn’t offer in a group context;
 Interviews can be an excellent source for stories and context;
 The interviewer can observe the non‐verbal behaviors of an interviewee.

34
Disadvantages (WBI Evaluation Group, 2007)
 Time requirements for interviewers and interviewees can be significant;
 Interviews have the potential to reduce the scope and sample for data collection;
 The results of multiple interviews may contradict each other or be difficult to analyze;
 Interviewees may be biased or represent only a limited perspective on performance
issues/themes;
In addition to the advantages mentioned above, interviews are more precise and accurate compare to
questionnaires. If interviewer does not understand the given answer then s/he can ask it again or refer to
a different point to discuss that answer. However, in the questionnaires participants only answer the
questions on the questionnaire and person who has written that question has no option to ask to her/him
again if answer is not clear. Moreover, at the interview more questions can be added to the question list
or questions may be changed simultaneously related to the given answers. Towards those given reasons,
in addition to the questionnaires, interviews had arranged in order to obtain more accurate results.
However, as mentioned above, little amount of extra time (1 day) spent on interview and that caused
time consumption. Moreover, as some of the interviewees did not want the interviews to be recorded,
author had to memorise and write down their answers as fast as possible but at the end some of the
answers were missing and that was not an accurate solution for results.
Case Studies:
Advantages (Palena N. et al., 2006 & Dr. Don. C, 2011)
 Provides much more detailed information than other methods,
 Allow one to present data collected from multiple methods (i.e., surveys, interviews, document
review and observation) to provide the complete story;
 Good source of ideas about behaviour;
 Good opportunity for innovation;
 Good method to study rare phenomena;
 Good method to challenge theoretical assumptions.
Disadvantages (Palena N. et al., 2006 & Dr. Don. C, 2011)
 It can be long
 Not generalizable
 Hard to draw definite cause-effect conclusions
 Possible biases in data collection and interpretation
For this academic research case studies are not carried out but previous studies are used for both
sustainable and traditional buildings. For the benefits of using case studies, they were very detailed and
accurate. It was easy to conclude outcomes from the data. However, some of the required data, like
brands any specific types of the sustainable systems that are used in the buildings, were not mentioned
in the case studies. Therefore, all the necessary required data could not obtained.

35
RESULTS AND DISCUSSION
1-Awareness on key sustainability issues in buildings
Table 3 shown below represents the results of the interviews and questionnaires in terms of awareness
of sustainability in buildings. Results were interpreted from the given answers and combined with the
table 3. Explanation of the scaling values; 1= no idea about topic, 2= few knowledge about topic, 3=
enough knowledge about topic, 4= clear knowledge about topic, 5= highly sophisticated knowledge
about topic.
Table 3: Awareness on sustainability issues in buildings
Question
Topic
Response (%)
1 2 3 4 5 Mean
Score
Aim of the sustainable buildings 0 33.3 41.7 25 0 2.91
Importance and necessity of the sustainable
buildings
0 41.7 50 8.3 0 2.65
Sustainability issues and regulations 0 16.6 58.4 16.6 8.4 3.17
Difference between sustainable buildings and
traditional buildings
0 8.3 41.7 41.7 8.3 3.50
Energy consumptions of the sustainable
buildings and effects on the global warming
8.4 25 50 16.6 0 2.74
Energy consumption materials at sustainable
buildings
0 25 33.3 33.3 8.4 3.25
CO2 emissions of the sustainable buildings and
effects on the global warming
0 41.7 50 8.3 0 2.67
Average 2.98
Average value indicates that respondents have enough knowledge on sustainability in buildings.
However, it also indicates that they have to improve their knowledge about sustainability.
The majority of the respondents have enough knowledge about the aim of the sustainable buildings
whereas, there is 0% highly sophisticated knowledge about topic.
The majority of the respondents also indicate that they have enough knowledge about:
 Importance and necessity of the sustainable buildings (50%);
 Sustainability issues and regulations (58.4%);
 Energy consumptions of the sustainable buildings and effects on the global warming (50%);
 CO2 emissions of the sustainable buildings and effects on the global warming (50%);
Moreover, results shows that there is a good understanding and clear knowledge about the difference
between sustainable buildings and traditional buildings (41.7%) and the energy consumption materials
at sustainable buildings (33.3%).
The above results clearly indicate that most of the respondents have enough knowledge about
sustainability in buildings. However; they have to be more aware about sustainability. This shows that
some people are working at a sustainable building project by knowing the importance of the
sustainability and having a good knowledge about what is sustainability, what are the effects of it and
why it is necessary; whereas, some people are working at a sustainable building project just as it is
popular these days, interesting and sophisticated. Also, building a sustainable building without knowing

36
enough knowledge about sustainability may cause some economic problems or usage of wrong
materials.
2-Energy consumptions and CO2 emissions of both sustainable buildings and traditional buildings
Traditional buildings in this thesis were assessed with the conditions of the Department for
Communities and Local Government (DCLG). Certification criteria have started to be applied to the
buildings by Department for Communities and Local Government in order to lower the energy
consumption of the buildings in the UK and as DCLG has the responsibility to fulfil the requirements of
the EU’s Energy Performance of Buildings Directive about buildings.
According to the website of the UK Government, the Directive requires that:
 All properties (homes, commercial and public buildings) must have an Energy Performance
Certificate (EPC) when sold, built or rented
 Larger public buildings over 500m² must display a Display Energy Certificate (DEC)
 All air-conditioning systems over 12kW must be regularly inspected by an Energy Assessor
Energy consumptions are estimated by assumptions for buildings and those estimations can be used in
order to compare same types of buildings to understand the approximate energy consumption of the
building(s). Moreover, this certification requires and includes CO2 emission of the buildings.
In this thesis, certificates of the buildings are being used in order to obtain data about energy
consumptions and CO2 emissions of the traditional buildings.
Figure 29 – Certificate of Tower D
For sustainable buildings, energy consumption data, sustainable energy systems which are used in the
buildings and CO2 emissions of the buildings are directly obtained from the companies which
constructed the buildings and the data is used with the permission by informing the companies about
thesis.

37
2.1- CO2 emissions of the traditional (non-sustainable) buildings
Table 4 shown below represents the results of the assessments of the seven traditional buildings in
terms of CO2 emissions related with electricity and heating.
Table 4: 𝐂𝐎 𝟐 emissions tonnes per year of the traditional buildings between 2012 and 2014
Buildings Types of energy systems January 2012 January 2013 January 2014
Tower A* Electricity 575 550 620
Heating 220 215 205
Tower B Electricity 408 407 409
Heating 195 190 185
Tower C Electricity 313 310 313
Heating 154 150 145
Tower D Electricity 573 570 532
Heating 115 113 111
Lecture Centre Electricity 910 921 900
Heating 520 530 525
Howell Building Electricity 550 530 510
Heating 232 232 245
Halsbury Building Electricity 918 900 790
Heating 306 304 298
*indicates the building which has an increase at the 𝐶𝑂2 emission between 2012-2014
According to the results; total CO2 emission of Tower A has been increased 3.77% since 2012. This is
due to increase in the level of the electricity usage and decrease in the level of heating from 220 tonnes
per year to 205 tonnes per year. This shows that CO2 emission of the heating can easily be lowered than
electricity.
For Lecture Centre and Howell Building, there is a decrease in the total CO2 emission levels since 2012
and this is related with the CO2 emissions of the electricity usage because CO2 emissions for heating
usage have been increased since 2012 and it is related with the climate and the “outside temperature.
For Tower B, there is a 1.51% decrease at the total CO2 emission level since 2012 and this is related
with the CO2 emission of the electricity systems. It has increased 0.25% since 2012. However, results of
the last three years are kind of same. Therefore, this 0.25% increase can be ignored.
For Tower C, Tower D and Halsbury Building, total CO2 emission levels have been decreased; 196%
for Tower C, 7% for Tower D and 12.5% for Halsbury Building, since 2012.
To sum up, there is an increase at the total CO2 emissions of the two buildings out of seven and as
Tower B’s CO2 emission level has been increased slightly, it can be ignored. However, increase at the
level of the CO2 emission of Tower A is not negligible and this increase can be related with the
electricity usage. As mentioned before in the literature review, electricity is one of the major reasons for
CO2 emission and this is a good example for that. During the winter there is a need for heating but
during the summer there is no need for heating therefore heating level can be count as zero. On the
other hand, there is a need for electricity both during the summer and winter. That is why electricity has
a major role on CO2 emission and it causes too much CO2 emission compare to the heating as shown in
Table 5. Therefore, more importance has to be given to the electric consumptions in the buildings in
order to lower the electricity usage. As assessed building are traditional buildings in other words as they
have 0% renewable energy source, they have to be converted into a sustainable building by using
sustainable systems and materials in order to lower the energy usage and CO2 emission.

Noyan Ulusarac Final Year Project

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