Environmental Sustainability in Construction

This report discusses the importance of environmental sustainability in construction and how to achieve net zero carbon emissions. It covers topics such as low carbon materials, innovative construction processes, renewable energy, and recycling. The report also includes a case study of a 3-bedroom bungalow and its construction materials and process, along with design strategies to meet net zero energy goals.

ENVIORNMENTAL SUSTAINABILITY IN CONSTRUCTION
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Introduction
A net zero carbon emission building is often achieved under circumstances the cumulative
amount of energy used per year by the structure is nearly similar to the amount of renewable
energy that a specific house generates on its real boundaries. This may be attained mainly
through the minimization of use of fossil fuel as well as any process which result in greenhouse
gases emissions in a structure of a home or construction materials, maintenance as well as repairs
of the structure. there are numerous technologies that are used in zero carbon design as will be
extensively elaborated in this report among them material selection that may be grouped as low
carbon emitting, the use of modern as well as more effective methods of construction through the
use of appliances that are good at saving energy, supplementing the supply of power through the
use of renewable energy sources alongside recycling or reusing different produces. It is of great
importance to note that homes that attain zero carbon energy emission use energy which is
mostly derived from the national electrical grid system and ought to on another hand kickback
nearly the same amount of energy in most of the cases.
Energy is not the sole aspect that needs to be taken into consideration in attaining net zero carbon
emission as it encompasses numerous interdependent connections of different parameters that are
as well inclusive of control of the emissions linked to disposals and wastes alongside embodied
carbon of materials for construction. The phrase embodied energy may be described as the
highest measurable energy used that is usable in the manufacture as well as transport of a
specific production all the way from the raw material forms to finished and consumable product.
On the other hand, embodied carbon refers to the maximum amount of emissions of carbon in
the process of production of a specific material. These should be kept to the lowest possible
levels during the construction of buildings to attain net zero carbon emission.

Another factor taken into consideration to significant levels in this study is cost. All the
techniques and techniques adopted in a construction of the homes that are aimed at zero net
carbon emission ought to result in lower overall costs as compared to those that are not. This
encompasses rough projection of costs which is inclusive of future repairs as well as
maintenance costs. The report in its entirety demonstrates the required changes that are to be
done to a current home to render it a home having zero net carbon emission.
Background
The construction industry and sector has a significant impact on the lives of the occupants of the
various spaces as well as the environment such that to the tune of about 45% of the energy
generated on the earth goes to residential habitats. Such energy and its consumption as well have
an impact on the environment as it results in change in climate alongside air pollution within
region where non-renewable energy which are polluting in nature remain to be dominant. More
insight continues to find its way into the world of the built environment as well as its impacts on
the surrounding thus measures are adopted by different stakeholder to come up with buildings
that are environmentally friendly through legislation as well as review of the existing building
codes in lowering the effects of climate change on the surrounding. Some of the main effects are
such as climate change and global warming that are already posing the worst hazards to the
planet including floods, increase in the ocean water levels and droughts in various regions of the
world.
An excellent illustration of a government taking necessary measures can be note in California in
which a detailed goal as well as mission alongside vision has been stated which demands all
current alongside future residential buildings to be changed to net zero emisions by the end of
2020. The vision as well provides that all commercial structures in the state are to meet the same

standards by the close of the year 2030. Such a vision is in conformity with the Energy
Independence and Security Act that came into action in 2007. The bill advocates for total
elimination of significant reduction in fossil fuel usage in new projects in the federation by 2030.
As a result of such actions, the contractors have been noted to be adapting and making the
necessary adjustments to ensure their construction work are as per the goals and with time zero
net certified homes would begin becoming the order of the day.
Investigation from the energy department of the USA indicates that building that has attained net
zero carbon emission status is defined by a building that is can significantly lower its energy
needed via maximizing energy effect via balancing the common energy needs with the
renewable energy available. Vigorous as well as articulate planning is not a choice in attaining a
home bearing such types of standards of energy usage. All the stakeholders must abide by the
regulations to enable setting the consumption of energy to the minimum levels and the extra
energy systems must be installed to facilitate production of energy by the homes.
The development of net zero energy emisions homes began as early as 2000 as a result of the
need to operate the economy on activities deemed to be environmentally friendly as well as to
lower the causes of changes in the climate. In the recent past, the government of the American
people has been can finish development of research facility located in Colorado which carried
out research on net zero emisions. The project managed to attain threshold of net zero carbon
emission through changing the process of design during construction. Numerous policies were
adopted during the construction all of which were aimed at energy saving that were inclusive of
additional energy sources for instance 16 MGW photovoltaic power through purchase
agreement. They as well incorporated natural day lighting, 100% natural ventilation as well as
creation of a data center that ascertained conservation as well as efficiency of energy.

Factors considered achieving a design technology for zero carbon
Selection of low carbon materials for ruction
Embodied carbon defines the cumulative carbon gases including carbon dioxide as well as
carbon monoxide during the entire production process of a given substance. One of the most
possible easy of attaining net zero emisions homes is through reduction of embodied carbon
which may be attained through two major options available in the construction sector: using
carbon sink as well as low carbon material. Low carbon material is taken into consideration for
this study
Low carbon materials are mainly using materials that are often recycled thus lowering the
cumulative volume of embodied carbon. There are numerous examples of low carbon materials
that have been developed in the recent past including:
A) Green concrete is one of the ways though it is rarely used. Primary materials used to make
ordinary concrete may eliminated and replaced with by products from manufacturing stage of
cement and other recycled materials from different sources. A very good example is carbon
intensive Portland cement, which is usually reduce and then adding fly ash as a substitute and
granulated blast-furnace slag.
B) Recycled metals are commonly well utilized in the construction industry. The process of
manufacturing metals involves a lot of carbon emission but their life cycle can significantly
reduce their production energy consumption. Recycled metals retain their properties hence
reducing manufacturing embodied carbon. Reusing metals can be used for several uses such as in
steel splices and still maintaining their structural strength.

C) Green tiles are cheap and usually locally available. They are made from over 50% recycled
glass. Through this waste glass is turned into useful tiles for buildings floors. The glittering
recycled glass qualities provide aesthetic quality to the final end product.
D) Low carbon bricks-Using fly ash in a great way helps reduce embodied carbon found in
conventional bricks.
Innovative processes of construction
Innovative processes of construction would be among them modifications of numerous parts of
the building to the conditions of output which result in net zero emissions. Such will be inclusive
of altering the building design to take into consideration such factors as day lighting, natural
ventilation optimization, envelope airtightness, microclimate optimization, reduction of window
to wall ratio as well as under floor supply of air. For instance in case the winds blow in the east
west direction in a given home, the longer axis of the building should be on the north south
direction to attain proper ventilation
Renewable Energy
Renewable energy refers to energy often extracted from renewable sources that naturally and
infinitely exist within the surrounding. They are among them energy from the sun, wind, waves
as well as rides. Energy from the sun and wind are the renewable energy that may be adopted in
a home or building setup. Solar energy is often automatically tapped using an avalanche of
devices including photovoltaic, solar heaters as well as concentrated solar power among others.
Photovoltaic systems work on the principle of using photoelectric effects in the conversion of
light to electrical current. Running turbines of various capacities are used in running wind power.
Biomass energy may serve as another excellent source of renewable energy.

Reuse and recycle
There are numerous materials within the setting of a building which may be reused. The two
major parts are the construction materials as well as water. Purification of water may do for use
in such roles is flushing of the toilets or even irrigation. Wastes including plastic bags may be
used upon cleaning thus lowering the volumes of solid wastes. It is as well of importance to
classify solid wastes into different groups such that waste materials for instance plastics may be
recycled thus lowering the levels of carbon emissions
Consumption and consumption behavior
Consumption behavior will involve the following: the various differences of setting thermostats,
plug loads, varying levels of light intensity produced by bulbs and different temperature levels of
hot water and the measure of intake by electric devices (Nejat et al., 2015).This involves the
demand for power, which varies depending on different occupants of a home. In order to achieve
net zero emission ones behavior must be directed towards energy saving. This involves the use of
energy friendly/conserving devices like the common energy saving bulb. Behavior such as
switching off lights/devices when not in use should be encouraged. This reduces the amount of
power wastage reducing the amount of carbon emission.
2.2 YH Detail a& 2.3 combined

Location map 1
Location map 2
YH DESIGN: 3 BEDROOM BUNGALOWS

BUILDING SURROUNDING OF YH
YHY
YH

YH Construction Materials
 Concrete blocks stone-used in wall construction
 Cement-used in finishes and in concrete making
 Fine and coarse aggregates (Lu et al., 2017)
 Timber-used in roof making and paneling
 Iron sheet-construction of the roof
 Steel-used in the case of reinforced concrete and in the making of steel doors, window
frames etc.
 Polystyrene- ceiling
YH Construction Process
Heating and cooling appliances include a central heating system for the house running on natural
gas, electric showerheads, electric kettles, water dispensers, and an electric heater. The selection
of construction materials for RH with minimum embodied carbon will include the replacement
of ordinary concrete with green concrete. Replacing concrete blocks with low carbon bricks.
Replace concrete floor with parquet floor. The polystyrene ceiling will be substituted using a
Bamboo ceiling. Construction material may be recycled in that waste construction aggregates
can be utilized to construct pavements (Asif, 2016).
Sawdust and timber waste can be recycled to form hardboards for the construction of flush doors.
Metals can be reused to make structural members. The construction process will change to
achieve minimum carbon emissions by redesigning the raft foundation into a strip foundation so
that the amount of concrete reduces (Heffernan et al., 2015). Shading of the building should be
done to avoid electric cooling during the day while a thicker wall with air pockets should be

constructed to avoid heating during cold periods. The floor should also be insulated using wood
or any other insulator. The design of windows should also be changed to make sure that the
house is well ventilated. All water-heating systems should be eliminated and replaced by the
solar water heater. On site renewable sources of energy will include harnessing power by the use
of solar panels and wind power with a wind turbine.
2.3. RH to meet net zero energy
Some of the design strategies of the redesigned house to meet net zero emission
 Eliminate double parking space to single to for the provision of more windows to allow
in more natural light
 The removal of this parking space allows for the changing of the position of the bedroom
window from the east-west axis to the north-south axis (Walker, Karvonen and Guy,

2015). This change of window location has an advantage to the space in that one will not
be experiencing direct sunlight rays, which are annoying at times, into the space.
 Increase windows sizes
 Building elevation by 1000mm since the site is sloppy. Elevation of the structure also
allows for ventilation naturally from beneath. This ensures the spaces are allows cool at
all times making them comfortable to stay in.
 Introduce roof vents. These vents will serve the purpose of cooling the attic space. A
well-ventilated attic also contributes to a good overall cooling of the structure. Good and
well-placed vents extend the life of the attic and roof structure in general. This saves one
a lot of cash that is needed for the repairs of the roof.
 Thermal chimney: This chimney assists with the vertical ventilation of the structure. This
chimney will make one not to rely on mechanical elements for ventilation. This will help
cut down power bills and we shall eliminate all the disadvantages that come with
ventilation devices. Such a disadvantage is emission of greenhouse gases to the
environment. By not using these devices, we shall have played a big role in the reduction
of the global warming that is caused by greenhouse gases (Kylili and Fokaides, 2015).
 Use of solar shading devices: windows that lie on the east-west axis, solar shading
devices should be incorporated during the fixing of the windows. Since this wing lies
along the sun-path, many sunlight rays may make their way into the building and excess
of the ray’s leads to a rise in the discomfort levels. In order to avoid this, the sun shading
devices are used since they can block some rays from getting into the building. However,
some of the design strategies may not be seen on plan.
TOTAL CARBON EMISSIONS

A) Construction materials establishment of constituent materials
YH RH
Concrete blocks bricks
Mortar
Tiles
-calculation of weights per m2
YH
The first step is to compute the concrete blocks area and multiply by mass to give mass per m2
1.08 m2 x 60.5 = 60.34kg
Mortar volume x density =mass per m2 (kg)
0.035 m3 x 1649.5 = 54.45 kg
It is then required that we apply the carbon factors
Mass in kgs x Embodied carbon factor = Embodied carbon (kg CO2e)
62.7 kg x 0.132 kg CO2e / kg = 8.379 kg CO2e
Mortar: Mass x carbon factor in (kg co2 / kg) = Embodied carbon (kg CO2e)
54.4486 x 0.174 = 9.474 kg co2
Overall embodied carbon YH
9.474 +8.379=17.853 kg CO2e

RH
Calculation of weights
Bricks: Quantity of bricks x Mass of a single brick (kg) = Mass per m² (kg) 60 x 2.3 kg = 138 kg
Mortar: Volume x Density (kg/m3) = Mass per m² (kg) 0.033 m3 x 1650 kg/m³ = 54.45 kg
Wall ties: Quantity x Mass of a single unit (kg) = Mass per m² (kg) 5x 0.04409 kg = 0.22045 kg
Apply embodied carbon factors
Bricks- Mass in kgs x Embodied carbon factors in kg CO2e / kg = Embodied carbon given in kg
CO2e
137.7 kg x 0.5513 kg CO2e / kg = 76.9 kg CO2e
Mortar-Mass in kg x Embodied carbon factor in kg CO2e / kg) = Embodied carbon in kg CO2e
54.4486 x 0.173kg = 9.420 kg CO2e
Wall ties- Mass in kgs x Embodied carbon factor in kg CO2e / kg = Embodied carbon in kg
CO2e
0.22034 x 6.509 = 1.437 kg CO2e
Overall embodied carbon RH
1.437+9.474+76.066=86.91kgCO2e
2.6 Estimate cost and benefit (e.g. energy saving) of RH in comparison with YH

The whole year energy consumption for the RH and YH was done separately. The
simulation result in the Energy Plus shows that there is a significant reduction of energy
consumption in RH compared to the one experienced in YH
.
Energy saving for RH and YH in a year
City YH RH Saving
percentage
Nairobi 102.39 72.87 28.83%
To analyze the cost benefit of the RH, energy conservation measures cost has to be first carried
out. This energy includes electricity, gas, heating price, and cost of insulation materials, lights,
and windows and so on.
Payback time calculation for RH and YH
RHYH

Payback period for YH and RH
Analysis done shows that the redesigned house can achieve good cost benefit
performance. Improved technology measured can influence the performance of a building.
Conclusions drawn from this analysis show that the energy savings of the redesigned house is
around 24% and cost benefit analysis shows a period of up to 4.1 years without any maintenance.
Figure 1: Homer site renewable energy supply
YH
RH

Challenges of implementing RH
Attaining a building with zero net energy remains quite a challenge and especially
bearing in mind the anticipation of the occupants of the structure. Attaining this requires the right
setting of the building as well as the right teams even though it is even harder coming up with a
net zero energy building of greater than four stories. Most of the materials used in construction
including PV are often costly. Attaining the most desired orientation for a building is as well yet
another challenge as upon attaining such an approach it is able to save to the tune of 50% of
heating and cooling energy.

References
Asif, M., 2016. Growth and sustainability trends in the buildings sector in the GCC region with
particular reference to the KSA and UAE. Renewable and Sustainable Energy Reviews, 55,
pp.1267-1273
Heffernan, E., Pan, W., Liang, X. and De Wilde, P., 2015. Zero carbon homes: Perceptions from
the UK construction industry. Energy policy, 79, pp.23-36
Kylili, A. and Fokaides, P.A., 2015. European smart cities: The role of zero energy
buildings. Sustainable Cities and Society, 15, pp.86-95
Lu, Y., Wang, S., Yan, C. and Huang, Z., 2017. Robust optimal design of renewable energy
system in nearly/net zero energy buildings under uncertainties. Applied energy, 187, pp.62-71
Nejat, P., Jomehzadeh, F., Taheri, M.M., Gohari, M. and Majid, M.Z.A., 2015. A global review
of energy consumption, CO2 emissions and policy in the residential sector (with an overview of
the top ten CO2 emitting countries). Renewable and sustainable energy reviews, 43, pp.843-862
Walker, G., Karvonen, A. and Guy, S., 2015. Zero carbon homes and zero carbon living:
sociomaterial interdependencies in carbon governance. Transactions of the Institute of British
Geographers, 40(4), pp.494-506