Shsce Term Paper

7/24/2019 Shsce Term Paper

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SUSTAINABLE

HABITAT AND

SOCIO-CULTURAL

ENVIRONMENT

TERM PAPER

TOPIC- EMBODIED ENERGY

OF BUILDING MATERIALS

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SUBMITTED BY:-

SHUBHANI AGARWAL

M.SC. RMDA (P)

CONTENTS

1) Introduction2) What is embodied energy?

3) Why is embodied energy important?

) !e" and recyc#ing o$ bui#ding materia#s

%) &o' 'ou#d the study o$ embodied energy he#p to

#o'er the energy consumption in the bui#ding

industry?() rimary consumption o$ energy

*) +o' embodied energy materia#s

,) +i$e cyc#e assessment

-) Embodied energy . e/amp#es

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10) Conc#usion

11) Case study

INT!OCTION

Think about the wide range of materials and products used in constructing our buildings today.

They are made by extraction of raw materials, processed, manufactured, transported to site, and

constructed as the finished building the energy associated with all these steps and processes is

what makes up the embodied energy of the building and its materials. This can also be

expressed in terms of the carbon dioxide emissions associated with this embodied energy,

defining the term embodied carbon

The other energy usage associated with our buildings is that used in running the building services

and other equipment in the building over its lifetime this is known as the operationa# energy

consumption for the building. The associated operational carbon emissions from the building

services are the basis of Building Regulations art ! "see TB# $%&. The embodied energy, and

the operational energy for the building over its whole life, can be added together to create a

'ho#e"#i$e carbon $ootprint for the building, perhaps the most comprehensive way to look at the

environmental impact of the energy and carbon associated with our buildings.

W&4T IS E56OIE EN!E78?

'mbodied energy is defined as the total energy inputs consumed throughout a product(s life)

cycle. *nitial embodied energy represents energy used for the extraction of raw materials,

transportation to factory, processing and manufacturing, transportation to site, and construction.

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+nce the material is installed, recurring embodied energy represents the energy used to maintain,

replace, and recycle materials and components of a building throughout its life.

'mbodied energy is typically expressed in -kg, where a mega /oule "-& is equal to 0.%12

kBtu or 0.342 k5h. The embodied energy values in aterial !*6' have been converted to -

per construction unit "i.e. ft3 for flooring, !6 for studs, etc.& and are listed for the cradle)to)gate

portion of the product(s life cycle, as highlighted in green in the diagram below

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C!4+E"TO "74T E

!a' materia# e/traction

Energy used to operate machinery

Transportation o$ ra' materia# to $actory

Type of vehicle used and distance traveled

affect embodied energy

roduct manu$acturing

Using raw materials and recycled materials

Transportation o$ $inished product to site

Type of vehicle used and distance traveled affect embodied energy

6ui#ding construction

Energy used to operate machinery

6ui#ding #i$e"cyc#e

Energy associated with maintaining and cleaning materials

5ateria# disposa#

Removal and disposal at end of material life-cycle


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7ssessments of embodied energy levels for common building materials have to also take into

account other factors including the energy used in transporting materials from production point

to construction site and, as energy savings with recycling can be significant, whether source

materials are raw or recycled. aterials with the lowest embodied energy levels such as

concrete, bricks and timber, are usually consumed in large quantities, whereas those with higher

embodied energy content levels such as stainless steel are often used in much smaller amounts.

'mbodied energy has been researched for decades and its main goal is to define the connection

between construction materials, the process of building and after coming impact on the

environment. The embodied energy itself can be separated in two categories8

*nitial embodied energy

Recurring embodied energy

5here the initia# embodied energy represents the energy used in extracting raw materials, their

manufacturing and their processing. +n the other hand a big part of the initial embodied energy

is consumed due to transportation to site and constructing the building. Therefore, the initial

embodied energy could be divided in two sub chapters, which would be 9irect and *ndirect

energy. The direct energy is used for transportation and the indirect energy is used to acquire

process and manufacture the building materials. The recurring embodied energy is actually the

energy used during the life cycle of the building, used to maintain, repair and restore or replace

materials. 7 building becomes more energy efficient, when the embodied energy of the building

is decreasing due to the long lifespan.

W&8 IS E56OIE ENE!78 I5O!T4NT?

5ith much tighter Building Regulations, and improvements in construction standards such as

air)tightness and increased insulation, new buildings are becoming more and more energy

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efficient. :se of low and ;ero carbon energy supply on)site, such as < panels and solar thermal

hot water systems, further reduces the operational carbon emissions associated with new

buildings. This means that, in terms of the total whole)life carbon footprint of our buildings, the

embodied energy and carbon emissions are becoming much more important in relative terms.

The graphs below shows typical data for the embodied and operational energy for two different

levels of typical construction for new homes over a lifetime of =0 years.

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Diagram 1:Energy Consumption for a Typical Three-Bed house

Total energy

Energy

consumption

Energy in use

Embodied energy

5 10 15 20 25 0 !0 !5 50 55 "0 years

Diagram 2:Energy Consumption for a Low Energy house


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6or the >typical( house embodied energy is ?$0@ of the total over its life, whereas for the >low

energy( house the embodied energy is A0)10@ of the total. 6or non)domestic buildings is has

been estimated that the embodied carbon in a distribution warehouse was =0@ of its total

lifetime carbon footprint, whereas a supermarket, which uses a lot more energy, has an embodied

carbon content of 30@ 3.

!E"SE 4N !EC8C+IN7 O9 6I+IN7 54TE!I4+S

Re)use of building materials commonly saves about % per cent of embodied energy that would

otherwise be wasted. There are significant energy savings to be made by recycling of materials,

though this is variable C for example, recycling of aluminum can save up to % per cent of energy

used in full production but only per cent of energy can be saved in recycling glass due to the

energy used in its reprocessing.

otential energy sa!ings of some recycled materials

5ateria# Energy re:uired to produce

$rom ;irgin

Energy sa;ed by using

recyc#ed

4#uminum 2%0 -%

#astics -, ,,

Ne'sprint 2-, 3

Corrugated

Cardboard 2(% 2

7#ass 1%( %

"ource: #$ome Energy 2%1%&

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Total energyEnergy

consumption

Energy in use

Embodied ener

5 10 15 20 25 0 !0 !5 50 55 "0 years


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W&4T C4N WE O TO !ECE E56OIE ENE!78?

Source< Co#e and =ernan study >1--()

7rchitects, interior designers, and engineers need to be conscious of the embodied energy of the

materials specified on pro/ects so that they can select products that help reduce the overall energy

footprint of buildings.

Diven that the envelope and structure alone account for approximately 0@ of a building(s total

embodied energy, we can reduce the footprint of our designs by selecting existing buildings for

interior build)outs, renovations, or adaptive reuse pro/ects.

*nterior finishes account for approximately $A@ of a building(s embodied energy, so adaptive

reuse or interior build)out pro/ects have an overall smaller energy footprint that new

construction.

7 study conducted by reservation Dreen !ab examined the impacts on climate, resource,

human, and ecosystem associated with renovation and reuse pro/ects. The study found that a

building that is A0@ more efficient than an average)performing existing building will take $0)20

years to overcome the negative climate change impacts related to the construction process.

Eowever, selecting a renovationreuse pro/ect is not enoughF the quantity and type of materials

used in the pro/ect is also important. 6or the most positive impact, we need to select materialswith lower embodied energy, higher durability, lower levels of toxicity, and overall favorable

life)cycle impacts.

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SALES

ENVELOPE

STRUCTURE

FINISHES

CONSTRUCTION

SERVICE

SITEWORK

4;erage initia# embodied energy o$ an o$$ice bui#ding

&OW WO+ T&E ST8 O9 E56OIE ENE!78 &E+ TO +OWE!

T&E ENE!78 CONS5TION IN T&E 6I+IN7 INST!8?

The most common problem of the world and the most recently discussed topic is how to save

energy. There are many researches done on providing new sources of energy such as wind, water

or solar power. *f we lower the energy consumption for domestic purposes it would be only a

small part of world(s in total. Therefore, we have to think globally. 5e have to think of new

solutions to lower the energy consumption in the industry ;one.

!ow embodied energy analysis would be a great solution to the world known problem and the

construction sector. 7 big part of the energy consumption can be reduced by planning and

predicting the process of constructing a building and all the activities in connection with that. 6or

example, a research on where would it be most appropriate to get the materials for the

construction can lead us to lowering the embodied energy of the building in means of

transportation.

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7nother efficient way to drastically lower the energy consumption is by using raw materials

located on the site instead of using manufactured materials from a factory located away from the

area of building. 6or example, a great choice of material will be using stones found on the site

while digging the foundation of a building and manufacture them on the site by hand or by the

usage of very low)consuming energy equipment. Ganadian scientists calculated that the

embodied energy of stones is 0.4% -kg, which is three times less the embodied energy of

bricks "3. -kg&.

The great amounts of construction waste in the world are reaching a disturbing level and many

manufacturers are starting to use the waste into producing new materials that could be as

efficient as the one(s manufactured from raw materials. This process could be defined as

recycling materials and it allows us to lower the energy consumption in the construction industry

drastically.

7 big part of the waste is also reinforcement used in concrete and is extremely easy to recycle or

reuse into new buildings. *n this way we could save energy and lower the embodied energy of a

lot of buildings and also prolong the life span of raw material resources. 7 great example of

recycling materials is the recycling of bricks. Hcientists say that seven recycled bricks are equal

to $lof oil.

etals such as steel have a rather high embodied energy, but if recycled we can save from 10 up

to %0 per cent of the energy used for extracting ore.

Recycling also has its disadvantagesF it has to be done in a local facility or in other words a

factory close to the demolished building, if the construction waste has to be transported to distant

location the consumption of energy for oil changes everything.

!I54!8 CONS5TION O9 ENE!78

The primary consumption of energy in producing materials is actually the energy needed to

manufacture the building product. 5hen calculating the primary energy consumption the most

important factor is the combustion value, which is the amount of energy produced by the certain

material if burned as fuel and it is mainly included in the primary energy source. *f we don(t

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include the combustion value this can lead to wrong results. The primary energy consumption is

around 20@ of the total energy input in a material and is separated as it follows8

The energy used in the extraction of raw materials and the production process are defined

as the direct energy consumption +f course this depends on the type of machinery used

during the process of extraction and the machinery(s energy consumption.

9uring the process of manufacturing the energy consumed is called secondary energy

consumption which refers to the energy used for heating, ventilating or maintenance of

the given factory.

!ast but not the least is the energy consumed for transportation

+OW E56OIE ENE!78 54TE!I4+S

There are many factors that need to be considered when we are defining low embodied energy

materials. ainly in consideration is taken the energy used to produce the certain material, the

energy used to deliver it and build with it on site and the energy used to maintain it after words.

*n the past many of the products used into a construction were found and manufactured on site.

Huch materials as stone, timber and mud have been the most common to be used in building

structure. #owadays these materials are to be replaced by concrete, steel and bricks. The newly

developed techniques of building, consume greater amounts of energy due to the usage of heavy

machinery. *n the past most of the construction materials were manufactured by hand or used in a

raw form, which means no energy was used to build a house. 7 material with low embodied

energy can be defined by the following factors8

Eow far the materials have to travel "local materials are better&.

The amount of raw materials used.

Eow difficult it is to actually manufacture the product "the more complex the processes is

the more energy is being used&.

The si;e of the building should be connected with the needs it has to fulfill, the waste of

space leads to higher usage of energy due to extra materials needed.

Eow much waste do you have during production and if the waste could be reused.

Recycling possibilities of the given material

'fficiently design the building so the use of energy and materials is lowered.

The most common types of low embodied energy building materials are8

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ud bricks

Htabili;ed earth

7ir dried timber

Goncrete blocks

recast concrete

Recycled materials that don(t require the usage of raw materials as they are already

manufactured once.

9ON4TIONS 64SIC ST!CT!E 4N C+4IN7

I54CT

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!E"!OCTION

"eg. mineral extraction&

water pollution

air pollution

9amage to ecology and landscape

Transport

Hocial impacts

5aste

!OCTION

"eg. manufacturing of components&

5ater pollution

ollution

5aste

CONST!CTION water pollution

air pollution

9amage to ecology and landscape

Transport

Hocial impacts

5aste

IN SE 4N 54INTEN4NCE water pollution

!ocal air pollution

Traffic generation

*ndoor environmenthealth

considerations 'nvironmental aspects of paint

removal and

Repainting

EN O9 +I9E

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ecological and landscape

implications

5ater pollution

air pollution from incineration

Hcope for recyclingamount

actually recycled

9isposal of demolition waste

E56OIE ENE!78 . EA45+ES

The following examples show how the embodied energy of alternative materials compares for

some typical construction alternatives, based on an !G7 which covers >cradlegate( processes

which excludes transportation and construction process impacts.

54SON!8 W4++S . EA!ESSE IN 54SS TE!5S

54TE!I4+ E56OIE ENE!78 >5D=g)

Bricks "common& A.00

Goncrete block"$0mm medium

weight&

0.4$

7erated block A.0

Rammed earth 0.1

TI56E! !OCTS " EA!ESSE IN 54SS TE!5S


Timber "general& 2.

Dlue laminated timber $3.00

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Hawn hardwood 4.1

lywood $.00

ST!CT!4+ E+E5ENTS . EA!ESSE IN BO+5E TE!5S


Dlue laminated timber %=00

Hteel $%0A30

Goncrete"$8$88A eg in)situ floor

slab, structure&

3==1

CONC+SION

5e can conclude the following points8

Ieep embodied energy down ) but without compromising efficiency in use or overall

environmental impact. inimi;e energy in use through high standards of insulation and any other practical

means. 9esign for long life "at least =0 years and preferably more&.

*f possible, specify a high proportion of recycled or recyclable materials.

urchase locally produced materials to minimi;e transport energy.

9o not install ultra)high)tech equipment that offers only marginal energy savings in use.

7void systems with high maintenance requirements or which need frequent replacement.

7void systems which rely heavily on user regulation to achieve energy savings "e.g. use

intelligent, self)regulating passive stack ventilation rather than user)controlled systems&. inimi;e embodied energy costs by including features from the outset rather than

retrofitting. :se natural materials, as these tend to have lower embodied energy and fewer

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'nvironmental impacts than heavily processed ones.

C4SE ST8

Gole and Iernan studied the embodied energy of a typical Ganadian office building constructed

from three different structural systems8 wood, steel, and concrete. The case study building was a

1=30m3, three)storey office building located in Ganada. The following figures were produced

from the findings.

*n 6igure $, the distribution of the total initial embodied energy for the building averaged over

steel, wood, and concrete construction. *t was found that the building services, envelope, and

structure each account for roughly one quarter of the initial embodied energy in the average

Ganadian office building.

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Total nitial Embodied Energy of a Typical Canadian .ffice Building '!eraged .!er

"teel, /ood, and Concrete Construction #Cole 0 ernan, 13&*


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In Figure 2, a comparison was made between the initial embodied energy and the

recurring embodied energy for the case study building over 100 years. The results for

the wood building type were plotted; however, the results for the steel and concrete

buildings would exhibit a similar overall trend.

The results show that over any significant life-cycle, the recurring embodied energy

associated with the building outweighs the initial embodied energy. Also, there is no

recurring embodied energy associated with the structural system. Therefore, after the

structure of the building is erected at time zero, its assumed no major maintenance or

repair has to be done to the structural system over the buildings life span. Thus, any

differences in embodied energy between a wood, steel, or concrete structural system

occur initially. The initial embodied energy of the structural system varies depending on

whether wood, steel, or concrete are used, plus there is no recurring embodied energy

associated with the structural system.

Results of this study show that beyond 50+ years the recurring embodied energy

associated with the finishes, envelope, and services completely dominate the embodied

energy of the overall building. Therefore, the focus should be on reducing the recurring

embodied energy of these three components as a first step in reducing the embodied

energy of the overall building.

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nitial Embodied Energy !s* 4ecurring Embodied Energy of a Typical Canadian .ffice

Building Constructed from /ood o!er a 1%%-5ear Lifespan #Cole 0 ernan, 13&*


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6igure A compares the total initial embodied energy of a typical Ganadian office building vs.

material type. Gole and Iernan found there to be a difference in the initial embodied energy of

the three structural systems8 wood, steel, and concrete.

The initial embodied energy for the wood structural system was found to be about @ of the

initial embodied energy of steel structural system and about 43@ of the initial embodied energy

of the concrete structural system. Gole and Iernan found very little difference in the initial

embodied energy for the other parameters8 site work, construction, finishes, envelope, and

services depending on which structural system was chosen. 7lso, the initial embodied energy

that(s associated with the choice in structural system is a fraction of the total initial embodied

energy for the entire building. *t was found that the combined effect of the non)structural

components such as8 building finishes, envelope, services, etc. outweigh the initial embodied

energy of the structural system. Thus, although there is a difference in the initial embodied

energy of the structural system depending on which material is chosen, these discrepancies are

minor in the greater picture.

Things such as the building envelope, services, finishes, etc., which are common across all

structural systems, often contain greater proportions of materials with very high embodied

energies like copper and plastic, which tend to dominate from the standpoint of embodied energy.

-ustification for using one structural system over another cannot be made based on initial

embodied energy figures alone, rather it must be based on a holistic life)cycle assessment of the

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greater goals. 6urther, examining the typical operational energy for a building, the embodied

energy in a typical building is less than $@ of the overall energy consumption in a building.

Glaims of using one material over another based on initial embodied energy arguments should be

made in consideration of the fact that embodied energy is a relatively small component of the

overall energy use in a typical building.

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Total nitial Embodied Energy of a Typical Canadian .ffice Building !s* 6aterial Type

#Cole 0 ernan, 13&*


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!E9E!ENCES

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http8www.willmottdixongroup.co.ukassetsbrbriefing)

note)$1)embodied)energy.pdf

https8www.ucviden.dkstudent)

portalfiles$0A%%4==!owJembodiedJenergyJmaterials

JinJsustainableJdesignJbyJ!a;arJetrov.pdf http8www.arcom.ac.uk)docsproceedingsar30$3)$10$)

$1$$JHattaryJThorpe.pdf

http8media.cannondesign.comuploadsfilesaterial!if

e)%)=.pdf

http8www.sustainablehomes.co.ukortals=A$22docs

'mbodied@30'nergy.pdf

http8cn)sbs.cssbi.caembodied)energy)case)study

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